Monday, June 3rd, 2002
It's the first day of summer research, there are 6 people working in
the lab, two of them are here for the REU physics program. Basically,
we talked general things about doing research here, and I have to
finish up my incomplete WISE187 report, so I have to take a look at
what I wrote on the report, and change it to make it perfect. Besides
that, I was reading the book called "LINUX in 10 Minutes", it's very
easy to understand, and I read about 4 chapters. About 4:00PM I left
Tuesday, June 4th, 2002
Second day of research, again, I was reading the book about LINUX, I
think it's a great book, and then I started to think about what I have
to do for the WISE report and learning the LINUX command, also HTML
commands. I like to work with computers, so I enjoyed learning
those. Also I decided to come here in the morning and after classes,
oh well...I think I "have to" come after classes anyway, otherwise I
will be delaying so much on my project while everyone else has a great
result already. Well...I guess I really have to sacrifice my sleep
Wednesday, June 5th, 2002
Today I first started to edit my WISE report. When I wrote the report
last semester, I had less knowledge about this topic than I do
now. Therefore, there were things I wrote in the report that reflects
my misunderstanding. It mainly was on the the explanation on my graph
and the data. I did few search on the web about the laws we found out
and things relates to my topic. I found the general function for Power
Law and Zipf's Law:
Power Law ==> Y= CX^n
Zipf's Law ==> Pn ~ 1/(^a)
After discussing with Dr. Noe, we found out that even Zipf's law has
the similar graph like power law does, it's mostly for statistical
use, which is irrelevant for my graph and data. On the other hand,
Power Law is most likely the right function I should look up; I also
need to find some informations about hyperbolic graphs.
Dr. Noe also found a book talking about 80/20 rules, which mentioned
power law in their data distribution for network linking. It's very
interesting, but this book didn't mention much useful
information.There was one thing mentioned in the book that their data
is "scale free", and it means that any segment of data selected to be
looked at obeys the functionality(??) of the graph or any laws the
graphs implies to.
I'm getting used to the LINUX system more and more everyday. Also, I
have learned more about emacs commands, and am getting used to them more
and more.(I think it took me months to be familiar with the system
photoluminescence => The excitation is caused by
electromagnetic radiation.(From the book "Luminescence Screens.")
- Read "Glow and Behold" article again to get more information, and
learn more about it.
- Look up web for information about
photoluminescence, try to find books in the library about it.
Thursday, June 6th, 2002
Today, while I was here this morning, I was surfing on the web and in
the school library system trying to find information about
"photoluminescence", "luminescence", "phosphorescence", "Power Law",
and etc. In the school library system I found few books that might be
useful for myself as reference, but 4 out of 6 books are stored in the
Chemistry library...made me think about if I am looking into the wrong
direction(field), but it's better to know more.
After I came back from classes, I read the whole article of "Glow and
Behold" by Ian Ashdown, and took notes from it. The last time I read
it, I was just scanning through the article, trying to find useful
things to put in my abstract. This time, I learned a lot from this
article, it's very interesting, I have more ideas about
photoluminescence, especially phosphorescence. However, the author
also mentioned about the content of the material, which is the
chemical part, which is also the part I don't like, because I don't
like chemistry, and I never did well in it. The question
raised(actually, it raised long time ago): Should I go deeper find out
what's inside the materials(samples) and knowing the reason why it's
trapping the light and which substances put together would have the
best effect? Or I should just perform similar experiments with
different conditions, like I stated in the abstract?
If I also go into the chemistry direction, actually, a lot of
things have been explained in this article already, and the contents
of the materials are mostly known, since most phosphorescent material
are made of similar substance. However, it should be intersting....I
should think about what I really want to do, and how to make the
project not to be boring and too simple....
Friday, June 7th, 2002
This morning, I borrowed some books from library: "Luminescence in
Chemistry", "Photoluminescence of Solutions" and "Theory and
Interpretation of Fluorescence and Phosphorescence". I read a few
pages of two of the books, but I haven't quite understood the things
mentioned in the books. Maybe I need to read over and over again to
get something out of the books.
I read the book "Luminescence in Chemistry", and this book mentioned
that phosphorescence is in a triplet-triplet excited state, so that
the electrons are trapped in the state, and that's the basic idea
about how the light can be stored and emitted even after the excitation
source is gone. A long-lived luminescence lifetime is 10^-4 second,
and phosphorescence's lifetime is usually longer than that, therefore,
it has the ability to emit light after minutes, hours or days.
* Phosphorescence are referred emissions from the phosphors where
electrons are slowly released from traps.
* Phosphorescence is radiative transition between states of different
* Fluorescence is reserved for light emitted as result of a
transition between states on like multiplicities.
* Triplet-triplet excited states:
1. Trapping electrons(energy is lower)
2. Two electrons with unpaired spin.
3. Return from triplet state to the ground state is forbidden.(Why??)
4. May last 10^3 seconds, which is called "metastable".
Monday, June 10th, 2002
* Copy and reorganize the note book to the scientific notebook(I finally have the notebook with me ^_^).
* Continue reading the book "Luminescence in Chemistry", and taking notes on it.
* Thought about starting to plan about new experiments....
* Going to borrow some more books about phosphorescence in solid
state, and the life time of it.
* It turns out the books that I borrowed so far, only the book
"Fluorescence and Phophorescence" by Peter Pringsheim is very
useful. Hopefully, I can get some other information about
phosphorescence in other books, even if they only have a little
portion about phosphors.
* Today's work: Went to the libraries trying to find books, and read a
little about the chapters that might be useful. Copied the notes I had
written on the notebook. I remembered the function I learned in
Calculus about growth and decay: Y=Yo*e^kt, as I look into it, , it
still leads me to the power law. Therefore, the growth and decay
function is not too useful either.
Wednesday, June 12th, 2002
I have drawn down some experiment ideas and setups (refer to my lab
book), which hopefully would be helpful for later use. I like my ideas
very much, but the more important thing to do right now is to learn
how to use the equipments, how do the equipments function, what
specialties do they have. Also, I should learn more about hyperbolic
graphs, and power law graphs. There are so much to learn, and time is
so limited, I am a little discouraged on doing the project
now. However, I have been trying to convince myself not to be
discouraged, but learn more. Hopefully, I will really learn a lot this
Thursday, June 13th, 2002
This morning, Dr. Noe gave a talk about some of the equipments that we
are going to use in the lab, such as the photodetector, Radio Shack
meter, and, the oscilloscope. It's interesting that the lasers have a
frequency of 5 kHz, which it produces a barely audible sound, but I
didn't hear it. Everyone in the group heard the sound, but I
didn't...I guess I have to get my ears checked. We also found out that
the computer screen flashes, and blanks for a very tiny fraction of
time. It was an interesting talk, and there are so much more than what
I wrote here, but I will just go straight to my little discovery
I did a little experiment on the light intensity at the first 2 or 3
seconds of samples after it's activated, and the intensity of light
source. I assumed that the intensity of light source and the first few
seconds on the sample should be the same, but they are not the same. I
tested both samples, and did a lot trails, so I assume my experiment
is very accurate. I was activating the samples while I measure the
light of the lamp at the same time, and hold the detector very close
to the sample, so it can reduce the intensity lost over the missing
second, and quickly go against the photocell. Taking down the data for
both samples over 5 times to take make sure it's accurate. Result
The light intensities are different, even if the samples were under
the same light source with the photodetector, it can't "trap" as much
light as photocell does. because the voltage I detected for the lamp
was 12.67 ~ 12.68, while the intensity of the sample B-330 after
activated was about 0.80 volts ~ 0.96 volts; and the intensity of the
sample B-901 after activated was about 1.028 volts ~ 1.557
volts. Which is about 11.3 volts difference from the lamp and the
samples. Therefore, my assumption at the beginning failed was
Another little note is that the time of activation is relatively
important, too, because when I activate the samples for longer time,
the intensity is higher, and when I activate the sample for only about
10 seconds, it doesn't have much voltage. Therefore, I assume that the
samples contains materials that can only hold a certain amount of
electrons, even if the light intensity is very high, and then the
electrons emit after all.
* When putting the detector in a distance from the light source, it
absorbs less light from it than putting it right against the light
bulb.SO, I assume (again) that the photodetector works better, in
another words, detects more light when it's held right against the
light source in an OPEN area; it should be held in a distance from
the light source in a CLOSED reflective surrounding.
Friday, June 14th, 2002
I have tried to connect the electronic night light, to measure the the
intensity of it, and then I found out(assume) that the
electronic night light, which contains similar substance like the
samples(I think), doesn't have a afterglow when it's unplugged,
besides, it holds less intensity than the stronger sample does. The
intensity is about 246.69 mV for the electric night light, but the
samples can hold at least 1 volt after it's activate, yet it takes
time to decay for the sample.
Why does the sample takes longer time to decay completely?
assumption is that the electric night light is kept activated by the
current when it's plugged, and the substance inside acts like a
"tranfer," which let the electron running through and shining, it
doesn't hold the light for any second. On the other hand, the samples
is not being activated by current, instead it's activated by the light
source, in my case, it's the lamp, so it doesn't keep glowing. In
addition, we can't see the glow light when the light is still on,
while the light is taken away, the intensity decays in the
samples. yet because of the electrons are trapped inside, it takes
longer time for the sample to emit the light afterward.
Few questions raised:
1.Why does the light light act like a "transfer", instead of acting
like a "trap"?
2.If they have similar materials to glow in the dark, why not both
taking time to decay?
3.Why can't the electric night light be activated by light, but the
4.The electro night light can charge up the samples for a
***The more questions I have for the comparison, the more I think the
electro night light is a fluorescent material.***
I think the night light is a fluorescent material, not a
phosphorescent material, even though the light it emits looks like a
phosphorescent light with a small amount of light intensity. However,
is that true? It's a very interesting question....
* Found a website about "blackbody radiation", a lot information
Monday, June 17th, 2002
I made a very BIG mistake by assuming the electronic Limelite to be
a fluorescent or phosphorescent material. It's a electroluminescent
material, which emit lights when the electricity comes through; and
the light shuts off when the current stopped. The LIMELITE I was
working on, electroluminescent material rather then photoluminescent
material, but it has a screen which shines like a phosphorescent
material. I went on a web page to read about the information of
electroluminescence, it's a very simple and helpful, and interesting
website, explaining about photonic devices. It also has explanation
for optic fibers. The website is actually a visual lab, which
interacts with users. It's at Photonic
I also learns about different types of detectors, semiconductors, how
does a semiconductor work, and etc. There is a lot information of the
page, which simplifies the explanation of some terms. It's easier for
me to understand the terms I read on other books.
There is one thing which I think it's a little hard for me to learn
about things, or communicate with others. Since I spent 4/5 of my life
in Taiwan, I learned most things in Chinese, knowing the terms in
Chinese, sometimes, it's hard for me when I don't know the vocabulary
when people talk about new things, which I know, yet I have no idea
about the English term. In addition, it also makes it harder to
explain to others about what I know. Of cause there are things that I
learned here, and I should be able to explain, but it's a little hard
for me to be able to talk in a professional way, which I should, with
others. However, I will try to overcome this new found obstacle, which
already exist for a long time. Hopefully, I will know more, and
gaining more knowledge in a way that I can easily understand.
It was just a little tiny feel about doing research, and trying to find
out things I am interested in, yet not knowing too much or not able to
comprehend as fast as others. If cause a little frustration comes
along, but hopefully, it will get over soon!
As I surf around on the web, I found something interesting in Uselessknowledge.com
(which the name of the webpage doesn't sound too convincing) about the
often-appeared green emitting light for glow in the dark
material. This webpages says that the original emitting light should
be pale blue for phosphorescence, but the green light, which is
brighter and more stimulating visually, is resulted from "fluorescent
dye". By adding different types of fluorescent dye, the color of
phosphorescent material can be varied to red, orange, or yellow.
In the afternoon, I spent sometime to set up the equipment for the
Limelite intensity v.s. distance. It's a very easy setup, yet I still
encountered a few problems.
Tuesday, June 18th, 2002
1.Abstract: To measure the light intensity of
electroluminescent material at various distances, and compare the
result with phosphorescent materials at time decay.
- Radio Shack meter.
- A 1 meter meter-stick.
- Limelite(Electroluminescent material used in this measurement).
Starting the LimeLite from the position of photocell,
measuring the intensity gradually till the intensity is equaled to
the background intensity, and record the data.
- Setup the steady position of photodetector, and the meter stick.
- Measure the background light intensity = 6.7 mV.
- Initial position reading = 2 cm.
- Place the LimeLite right in front of the detector to get the
initial intensity. Initial Intensity : 183.3 mV.
- Start to measure the intensity every one centimeter.(refer to the
chart in notebook)
- On the distance column, deduct the 2 cm from each distance to get
the actual distance.
- On the intensity column, deduct the 6.7 mV from each data entry to
get the actual intensity from the LimeLite.
- In addition to the data, at 49 cm, it turns to 7.2 mV; at 58 cm,
it turns to 7.1 mV; at 66 cm, it agrees with the background intensity,
which is 6.7 mV.
- Plot the data to the graphing paper.
- convert and plot the data to log to log scale and semi-log scale to compare.(refer to notebook)
After the LimeLite is positioned at 20 cm(Actual
distance from the photodetector is 18 cm), light intensity decreases
very slowly, it's about 0.1 ~ 0.2 mV every time it changes. Also, the
light intensity appears to be exponential, just like the graph we
obtained for the regular phosphor-luminescent samples.
Electroluminescence has similar property as
phosphorescence, that's why they are both decreases are
- Activated by LIGHT.
- Light decays exponentially v.s TIME.
- Afterglow exists.
- electrons are trapped inside the sample for a period of time.
- Activated by ELECTRICITY.
- Light decays exponentially v.s. DISTANCE.
- No afterglow.
- Electrons are not trapped inside the substance, they emit
immediately after it's excited.
Wednesday, June 19th, 2002
I am trying to read about how to program using Qbasic language in DOS
format, so I can measure the intensity of eletroluminescent material
according to the changing distances without concerning recording the
data timely, which is a function existing in the Radio Shack meter. I
will also be able to plot the data more precisely using the
* Didn't do much about anything today, just reading the book of Crash
Course in Qbasic.
* Went to see the metastable state helium lab
around the corner, and reminds me to read about the triplet
state. Actually, it's very interesting to hear about those things. I
will take a closer look at the triplet states and some other relevant
topics after my midterm tomorrow.
Thursday, June 20th, 2002
Today I was reading the materials Dr. Noe found on the web. I am not a
fast reader, so I read those webpages, and the paper very slowly,
trying my best to understand what they are talking about. I have more
understanding about the metastable helium, and the Bose Einstein
Condensation of neon. I have also encountered a lot of new vocabulary
in physics terms, and I also looked up the meaning of those. There are
still 4 more websites, and two papers that I have to read. but it's
very good, because the things I learned today are very interesting,
such as magneto-optical traps, and ionization(Not very sure
about it, but I think I get most of what's on the web.) So far while I
am reading about all these fascinating stuff, I almost forgot why I
have to read. In one of the webpages I read today, it mentioned the
lifetime of the helium about 7200 seconds(which Dr. Noe mentioned to
me yesterday already), most of the long lived atoms are the noble
gases(which I learned and have a clearer idea about it today, too). I
am trying to find the connection of all these long lived atoms with my
experiment, too. Maybe there are some connections and some properties
that phosphors have which are similar to the noble gases.
After my midterm, I felt more relieved, so I right now till my final
comes, I can concentrate more on phosphorescence and all these cool
and interesting facts found on the web.
I also put another temporary section of related websites Dr. Noe
found at the bottom of this webpage, and I will try to organize all
the websites I found which I have read through and I feel it's helpful
and understandable, to put on the link of "related website". Also, I
will put the websites one by one as I finished reading. I will bring
the Qbasic book back, and trying to read more about it, and writing a
Friday, June 21, 2002
This morning, I have been reading about the QBASIC book, it's very
interesting, because the commands are easy, and since I have learned
the C programming language, and Visual Basic language before, I am
very used to the commands, and getting the steps very easily. It might
also be because I am just reading about the commands that I will need
for writing the program to take readings from the meter not by time,
but manually. However, a big question if in my head all morning log,
that is: How can I convert the data reading RS meter takes to the data
in the basic program? How should I connect the RS meter and the
program I convert to something I want? I am keeping reading the book,
but so far, it doesn't say anything about connecting the QBASIC
program with other equipments. I hope I can find it soon. My goal for
today is to finish writing a program taking readings from the meter
without concerning the time.
I forgot to put other links that Dr. Noe gave to me the other day, I
don't think I would be able to read anything about those webpages
Another question: Do I want to write a program that record the data
directly from the RS meter OR do I want to write a program which just
put the data in a array and plot my data in many different possible
If I want to write a program with only the second type that I
mentioned, then what's the difference if I just use the spreadsheet
program inside the computer?Therefore, my question is solved....Yet,
the first question still hangs around there laughing at me....I better
find a way quick to write a program recording the data directly from
the Radio Shack meter.
After lunch, Dr. Noe had taught me how to connect the RS meter with
the QBasic program to take readings on it. The commands of connecting
it to a Basic program are on the owner's manual of the Radio Shack
meter. We successfully took readings to the program after experiencing
some minor problems. The only thing left is for me to write the whole
program out, and insert the commands to be part of my program so it
can take readings when I hit some key on the keyboard. I hope I will
finish the programming on Monday, so I can take the reading with the
RS meter again for a more precise measurements.
The last thing we did was to put my data, which I took by hand, into
the spreadsheet program. We plot the data in a log to log scale, and
it looks very straight(A very pretty graph, looks like the graph we
obtained earlier for the light intensity of phosphorescent sheets.) if
we ignore the first few positions( which the intensity drops
enormously.) We plot another line according to the hyperbolic formula,
which is L(t) = L(o) [b^a/(b+x)^a], where a, b and L(o) control the
curvature and the position of the plot. We tried to put in various
numbers of the three variables to obtain the best fit-in
curve. Besides the straight line part, we also tried to plot the first
few positions of the line, to see if that really fits the hyperbolic
formula. However, we found out it's hard to fit the first few
positions of the curve with the hyperbolic formula. We thought maybe
it's not a hyperbolic curve as we thought. On Monday, I should play
around with the numbers and to see if there will be any new discovery on
Monday, June 24th, 2002
Today, I was mainly reading on the webpages about Spin, and trying to
find out the definitions of a lot physics-related vocabulary. I
learned more about the relations in spins and triplet states. I also
learned about what does the symbols mean by J, it's the total angular
momentum in the states. Spin means a quantum-mechanical system
processes angular momentum,and the angular momentum is always a
multiple of h/2, where h indicates Planck's constant, which is 6.26 *
10^-34 J/s. I also read about the eigenvalues that relates to the
directions of molecules in spin states, but I don't really understand
what that really mean. I have learned eigenvalue and eigenvector in
introduction of linear algebra course, but it didn't say anything
about how eigenvalues are related to quantum physics. I will read more
about it, because I think it will help me to understand more about
There is one question about triplet-singlet states. If I remember
correctly, electrons can't go from the triplet state to singlet state,
because it's forbidden. However. on the webpage I read, it mentioned
that the molecules' energy consists many parts, and the energy
stored in triplet states may eventually decay back to the singlet
state. Does that mean that electrons can go back to singlet state
along with the energy decay?
I read too much physics related webpages and information in one day, so I decided to continue on reading the Qbasic book. I had a little talk with Alex and Owen about programming languages while I was reading the book, and I learned about different types of computer programming language have different usage, and each one of them is better to serve at certain kind of applications.
About my basic programming learning....Well, I am still reading the
book, because I have a little problem on how to use the array part. I
know it should be easy, but I don't quite understand the dimensional
array. Therefore, I was taking my time reading and interpreting
between the lines.
The lab is a little busy today, there are a lot people working in the
lab today, and I saw the guys taking some of the equipments the
hospital donated to their lab. I remember the last time I went to
their lab, I was fascinated by the setup. I don't know when will I have
enough knowledge to work on physics projects like those physics major
do. Hope it will be soon.
Tuesday, June 25th, 2002
Today, I was reading about the Qbasic book, because everyone else has
to use the computer, I can't keep on reading the webpages. I tried to
do a practice program on the computer, but it didn't work, I haven't
found out where the bug is, but I will try tomorrow. Sometimes, when I
read the program layout, it's like Latin for me; sometimes, it's very
easy to understand. I think I need to read more and do more hands on
practice on programming; or I think I should just start to write the
program. According to my speed writing a C program last semester, I
think I need to take about two days to sit there and program and
debug...Well...I like programming, just sometimes my logical sense is
off...Therefore...it will take more time for me to write a program. I
hope this one doesn't take too long, yet can run properly, and be
Wednesday, June 26th, 2002
This morning, I was reading on the websites of the students who are
working in this lab this summer, too. They all have a very descent,
well written, and very organized websites on their project, and they
all have a good explanation, and show a depth of their knowledge on
their project. Comparing their projects with my own, I feel shamed
that I haven't found anything that's quite interesting for people to
surf around and go "Oh, this is interesting, and very informative, I
should take a deep look on it." I am trying to understand and absorb
physics knowledge related to my project, since I barely learned
anything deep in this field. I hope I can catch up with other people
in this lab faster. I am actually waiting for my summer session 1 to
end, because my classes in the afternoon takes too much time for me
from the the lab, yet even if I come back from the class, I don't have
much time to stay in the lab. I am waiting for summer session 2 to
come soon, because by then, I can stay in the lab for a longer time
and hopefully I will get more things done in that month. Now that I
think about it, the regular REU students have to do a presentation on
July 26th, and if I don't have any major work done by then, how can I
present? Gee...Time really flies....@_@
In the afternoon, I was basically reading online about the Inverse
Square Law, which the formula of it looks like it fits to the graph we
obtained on Friday, on the data of intensity v.s. distance on
electroluminescent material. The formula for inverse square law is E =
I/r^2, where E is the illuminescence, and I is pointance, which the
unit is lumen, or steradian candela(
). To be more precise, the function should be E = I *
cos(angle)/ r^2, if considering the angle measurement in the
experiment. However, the inverse square law for light is under the
condition that assuming the light source is a point source, such as
light from the sun, or lights that's coming from beyond the double
focus length if a mirror is used as the object. If we assume the point
source is the shape of a sphere, the intensity at he surface of the
sphere is I = S/(4 * pi * r^2) (where Pi is the value of
3.14159....). If the energy is I at the distance r from the source S,
the energy at twice as far from the source is spread over 4 times the
area, so the intensity is reduce by a fact of 1/4. For more
information,check out the site
Inverse Square Law
Thursday, June 27th, 2002
I found out what the unit cd/m^2, which is mentioned in Ian Ashdown's
Glow and Behold article, means in the luminescent term. It's describe
in the link above. Candela per meter square is the standard unit of
luminescence. It's the luminous intensity of one candela radiating
from a surface whose area is one meter square. What does candela
mean? It's defined as the magnitude of an electromagnetic field, in a
specific direction, which has a power level of 1/683 watts, which is
equivalent to 1.46 * 10 ^ -3 w, per steradian at a frequency of 540
tera-herts(THz), which lies in the range of visible light spectrum.
Also, the unit puzzled me for a while is steradian, which I found out
that it's the unit of solid angular measure, that area A of subtended
portion of the sphere is r^2, r is the radius of the sphere. You can
refer to the graph on
I found webpages talking about inverse square law. The formula
provided by one of them is exactly the same like what Dr. Noe said: 1/
r^2. It's very interesting, because on the other pages talking about
inverse square law, the formula take the Intensity in account, and the
angles, too. One difference on this webpage The Inverse
talks about the brightness of the light is proportional
to the radius(distance). It shouldn't be any difference, but why is
there two different formulas even though they are very similar to each
I also found this website describing an experiment that
verifies that inverse square law, which is exactly the measurement I
did, except for the light source, they used a 60 watts light bulb, and
I used the electroluminescent LimeLite. The principle should be the
same, despite of the what the light source is.
From the link of Inverse Square Law in Astronomy, I came across this
vocabulary of Cephid Variables, which is a class of stars that their
brightness is varying over time period. By measuring the variation of
the brightness, we know how bright the star really is, and we can also
determine how far it is by measuring how bright it appears to be. It's
very interesting. Moreover, we can determine the age of the universe
by using Cephid Variables. It has a nickname of
. For more information about it, check out the
explaining the Cephid Variables. Also check out this website on
, it talks a little bit about the stars also, and
by clicking on the links they provide, there are also stories of
stars. If you want to see the graph on how it's related to inverse
As you scroll down, you will see the pretty graph
Friday, June 28th, 2002
On my page, there is a link of related weblinks, which Dr. Noe just
tranfered Peter's page to my page few days ago. I haven't modified the
page until this morning, which right now is pretty descent looking and
put together the links that I scatterly put on other pages. Now I have
put them onto one page, it looks much more descent and well
organized(I think). Moreover, it's easier for me to look up reference
from it, too. I also added few links and deleted few links that's not
useful, I will continue on modify it from now on. Hopefully, it will
be a useful page for myself, and people who are trying to look for
information on my webpage.
I was searching for reference on the history of phosphorescence, and I
found a page on the American Museum of Natural History. It's about the
nature of diamonds, and it mentioned that some diamonds have
fluorescent qualities, and some have phoshorescent qualities, which
they store the high energy of light, and emitting it for a period of
time, just like all other phsphorescent materials do. I thought it
would be inetersting because they have the pictures
of the shines of diamonds under different conditions . However, it's
just a comparison of diamonds when the fluorescent light shines on it,
and it's regular shine with daylight.
Prof. Metcalf came in today, and he told me that he read over my
journal and saw a lot things that I have misunderstanding or confusion
about on spin, triplet states, singlet states, and etc. Therefore, he
decided to give a talk in the lab, talking about the quantum physics
part, so that we can understand the basic of it, and have a idea about
what it is. I think it's very nice that he went over the stuff I wrote
on my journal, and I know I just wrote everything I did everyday, so
the jourmal is a little messy, and not well-organized. However, I
think, since it's a journal, I am not really concerned about
presenting things that I don't know on the web, because that's what I
don't know, and it will remind myself to work on it everyday. For now,
since I know that people would read over my page, I will be more
careful about what I put on the web, and learn more things everyday,
to show some real progress.
Monday July 1st, 2002
Today's goal for myself is to write the program out to remeasure the
light intensity of the limelite that I used before. I want to have a
more precise measurement, so I will be working on it today mainly, and
I think Professor Metcalf will give a talk sometime today, I am
looking forward to it.
Professor Metcalf's talk was very useful, even thought it was only
about the history of the physics, but it helped me to clear out some
confusions on the information I wrote in the journal. His talked about
the "what's wrong in the clasical physics" today, and he said that
there are some mysteries about physics. Ther are some phenomenons that
scientists couldn't explain in the 19th century and the early 20th
century. I found it very helpful today, the only I was still confused
about was the Bohr's statement about he could solve both Rutherford
and also the mystery of the dark spots of the sunlight...I think I
have to ask Prof. Metcalf to explain from that point on agian
tomorrow, because I found that there are so many things he mentioned
today were related to my little research on spins and triplet
states. So...Things should go smoothly from now on! ^_^
The high school students came, they all look very intellegent, and I
think they ARE intellegent. Dr Noe asked us to introduce ourselves
like when the high school WISE came, and talking a little about our
projects. I felt a little embarassed, I guess I am not confident
enough to talk in front of people about what I did, because I still
think that I didn't do much on my measurement, and I have to organize
my thoughts well on the projects. I mean, when people ask me to
describe orally about my projects, I feel shy and not confident, but I
can talk a lot when I write on my journal. I guess I need to practice
more on public speaking, and maybe take a course like "confidence 101"
to build up my confidence.
I am trying to write a program to measure the intensity accoording to
the distance using the limelite. I have a little lay out of the source
code, but I have problem about storing the data in a file so it can be
displayed later on regarding to the distance I input when the
measurment is done. However, I am totally stucked in this part. I want
to try on the c program first about storing data in a file, I think i
forgot how on the C program, so I am lost on the steps right now on
programming in the Qbasic...@_@
* Stuff to do tomorrow! Bleaching! why when shining the laswer light
to an activated sample, it creates a dark spot on the sample, and it
returns to the priginal glow again very soon?
I put in the command that I wrote so far in Qbasic, it's not perfect,
but I am just trying to put it in line by line, so I can read more
clearly, and easier to debug.So far, I have written down the basic
source codes, I guess I won't have too much problems on writing a
program taking the reading, but I am thinking about how to out the
data in a file, such that when I open the qbasic, it can just read from
the data file.
Tuesday, July 2nd, 2002
Just like yesterday, Professor Metcalf gave a talk about quantum
mechanics this morning. Everything was fine till the horrible wave
equation came out with theSchrodinger's explanation. Ironically, this
horrible wave equation can solve the mystery about blackbody
radiation, mm...I don't know what to say about it now actually.
After the talk, we had some visitors in out lab from the REU physics
group. We were basically describing to them about our projects, and I
was the second one to describe my project. I felt I am more
comfortable today to talk about my project, yet I forgot to mention
the most interesting part on my graph that the data appears to be
linear when poltting on a log-log scale.
Didn't do much this afternoon, I just simply made my webpages looking
prettier using the pictures I like. I am thinking writing a longer
"about me" part, but maybe not soon, because I am still thinking about
how should I make the meter take readings and convert to a
spreadsheet. Today, my mind is full of Qbasic programming, my programs
due tomorrow and my CSE113 final next tuesday.
Wednesday, July 3rd, 2002
Simply didn't do much today, just attended prof. Metcalf's talk, and
understood more about triplet state and singlet state. Hopefully I
will get the program done this weekend when I am not studying for my
final. I guess I need A LOT luck this time@_@
During the July 4th weekend....
I went to a BBQ on July 4th with my suitemates and people from REU
mineral physics and geology. It was alright, I don't know most of
people there, so I was bored, but they are all nice people, mostly
graduate students or junior and seniors in undergraduate.
I ran into my friend, who lived across the hall from me last year, we
hung out on Friday in the mall. I guess it's not a good idea to hang
out in the mall with friends, because I wanted to buy everything I saw
in the mall. @_@ Gotta control my urge of buying clothes....=P
I also created a personal website using one of the webhosting tools,
it's not complicated, but it's not done yet, when it's done, I will
post it up on the about me link. I also want to create another website
on school wegpage which I have requested. I want to start from
scratch, type in all the commands that I need. Hopefully I will get it
done by the end of the summer.
Othertimes, I was studying for my CSE 113 final. I hope I can get a
good grade on it...*Hope Hard*...
Monday, July 8th, 2002
I worked on my programming today, which I got the meter taking the
reading repeatedly, and recording the distance, too. However, I
couldn't get all the data converting to the spreedsheet format when I
attempted to read the file from the data. I think I have to work on
Tuesday, July 9th, 2002
Finally, my first summer session is over, but I don't think my final
was too good to pull my grade up too much, but anyway, it's
Yesterday, I have worked on the debugging with Dr. Noe(Actually,
Dr. Noe debugged it). Therefore, I cantake a more precised
measurement on the limelite, and also it would be helpful for many
things as Dr. Noe said (But so far I haven't thought of any good idea
to use the program with.) I am going to put my program on the webpage,
too. Hopefully it will help people who needs similar program to use. I
haven't decided which section I want to put the source code on, but it
will be on my page somewhere.
Today I'm exhausted already, but I am going to set up the computer to
my little setup for the lime light tomorrow, and work on it. I will
also reanalysing the data, and compare the data I will record
tomorrow. Hm....Let's call this paragraph of "goals for tomorrow". I
will also try to get more information about the inverse aquare law,
because I don't think I understand too well on the applications for
this law. I would also visit the website Dr. Noe showed me yesterday
about the 1 / f, which is the same as the power law. Since I will
have more time to be in the lab from now on, I will try to get more
Wednesday, July 10th, 2002
I have my setup on the back to work on the limelite reading taking
again, but as I was running my program, I found that the program
having a little problem on taking readings when there is no distance
value entered. I am working on it to it can go back to take the
reading while I do the measurement. So far, everything is working, and
if I can solve this little tiny problem, it would be perfect for my
Okay I solved the little problem by adding an IF statement in the
loop, so it would test if the distance added in is valid (Not a
negative number, and also not no-entry) It's working fine, I got
another set of data which I think it would be more precise. However, I
found out something tiny about the program that the program doesn't
recognize if there is two exactly the same entries. Well, I am not
going to worry about it, because I could always convert the data to
the spreadsheet format and modify the file to a readable format, and
also analyze the data from the spreadsheet.
So I have another set of data, which is mostly looking the same as the
one I took by hand. I haven't plug in the dat in the light intensity
function yet I don't know what would it come out like. It should be
the same because it's not a big difference. I will not spend too much
time on this measurement, which is basicly the same one like I did on
The next thing I want to do is to use the monochrometer to activate
the samples and take readings. Maybe I will see something
Thursday, July 11th, 2002
Alright, so my measurement on limelite is finished today, my program
is working well with the RS meter if following the instructions
well.(Make a note on the "if") I got few more data and tried to make
the background as dark as it can get, but I didn't take the
measurement on the background for each readlings separately. The
graphs look nice, and I think it fits the inverse square law pretty
much, all the floating datas were probably effected by the
noises. Therefore, my little project on the limelite is practically
done. I have learne how to program with Qbasic program, and I
connected the meter and the computer well. Starting tomorrow, I will
start on something else, setting up another measurement, and doing as
what Dr. Noe suggested to do measurements on the samples, which are
activated by sunlight. The only thing I have to concern is the timing
that I start the measurement, since I have run from outside to the lab
to start the whole thing.
I want to put the graph of limelight on the web, too, and also the
coding, but I guess I will just worry about it later, I haven't really
thought about how I want to organize my website to a better looking
format, and also a easier to find sources. Maybe I will work on it
during this weekend.
For the new experiment, as Dr. Noe suggested, I should improve the
setup of the equipments...but I think I will worry about it tomorrow,
too. I am being lazy now...After a whole day of thinking about why the
graph looked ugly before, and also trying to fix little problems in
the porgram I wrote to make it a better program....Hm...I need energy
supply to stay awake in my class later. @_@
Friday, July 12th, 2002
Another week has passed. This week, I was mainly focus on writting the
program to take a more precise measurement on LimeLite, but since I
already have a nice data on that limelite, I just took another few
readings on the limelite to test if the program work well with the RS
meter. Like I analyzed earlier, after plotting the data to the graph,
it tends to fit the hyperbolic formula. However, it's not 100% fitting
into it, the constants should be varied to certain combination that it
would fit mostly perfectly. I will do more research on it later,
because now, I should work on something new, like activate the samples
under sunlihgtm and produce the same experienment like what I did
The experiment: LimeLite Intensity Second
Abstract and objective are the same as the previous one.
- Meter stick.
- RS meter.
- QBasic Program - Trial.bas.
Experiment procedures are the same as the previous one.
- Initial position is 2cm, uncertainty is 2 mm.
- Initial background intensity is 0.3 mV, but the uncertainty is about
.05 mV, because the accurate reading on the RS meter is 0.1 mV, if the
meter reads 0.15, it may be round off to 2 mV, or 1 mV, therefore,
when analyzing the data, the uncertainty was taken into account. In
general, the reading was precise enough for plotting the
- Initial LimeLite intensity is 183.9 mV
observation is the same, I have gotten a very similar yet longer data up to the
distance = 100cm.
Only thng left for this program is to try to fit in a proper fuction in it.
Qbasic Program - Trial Source Code:
'Program taking reading from RS meter
'"Trial" created by Chungchi Chen, last modified July 11th, 2002
PRINT "Distance V.S. Light Intensity Measurement"
OPEN "reading.dat" FOR OUTPUT as #1 'Open(create) file for data recording.
PRINT "Please input a distance value"
Input "Distance="; Dist$ 'taking reading from keyboard.
IF (dist$ <= "0") OR (dist$ = "ent$") THEN
PRINT "Please give a valid input"
'take reading from RS meter
'open meter for reading
OPEN "com2:600, N, 7, 2, RS, CS, DS, CD" FOR RANDOM AS #2
'give the "D" command to activate meter
A$ = "D"
PRINT #2, A$
intensity$ = INPUT$ (14, #2) 'take reading from meter
PRINT "Distance = ", dist$, " ", "Intensity = ", intensity$
PRINT #1, "Distance = ", dist$, " ", "Intensity = ", intensity$
LOOP UNTIL(dist$= "999")
'print and store data on screen and print when the file is called
'print all data
The graph for the data I took with program is to be displayed as followed:
On the graph, the blue line is the data taken from the meter, and the
red one is the best fitting line, which we originally thought it
should be a hyperbolic function of I(x) = I(0) * (a^2/(a+x)^2), but it
turned out to be a variation of the hyperbolic curve, such that the
denonimator is not (a + x)^2, but it's (a + x^2). Therefore, the
formula of this graph actually fits much better to the function I(x) =
I(o) * (a^2/(a+x^2)), or the formula can be written as I(x) = I(0) *
(a^2 / ((a + x)^2 - 2ax)) as a functions that's more like hyperbolic
Values of parameters:
- a = 1
- x = distance (varies)
- I(o) = 183.9 mV (initial light intensity of LimeLite)
I took out the first reading on the data, because the first data is
the intensity of the limelite when it's held right against the
photodetector, such that when plotting the graph, it has a enormous
change from 0 distance to the first position, which is 1 cm away from
the meter, it doesn't fit with the rest of the graph..
Monday, July 15th, 2002
Today, I am working on figuring out to to improve the setup on the
next measurement that I am going to do with the sample activated by
sunlight. Now I know I can use RS meter program to take reading and
create a file, but I don't have a complete thought on how to make a
setup to take reading right against the photodetector. I am still
thinking a best way to make my equipment.
I am also thinking about my presentation on July 26th. I want to do a good presentation using existing datas and file I have, and maybe if I can finish the sunlight experiment and analyze it on time, I can present that, too.
* Had a headache for the passed whole weekend, and still having it
now, so my brain is not functionalling too well (when did my brain
function normally anyway? O_o). Therefore, I do everything so slowly
I have made a black box from paper board, which it's a completely dark
environment, and the photodetector positioned facing down. I have
tested the light intensity for thw whole blackbox setup, the meter
reads 0.00 mV and sometimes -0.01 mV in the black box. There wouldn't
be any light leaking in in the black box. The only that has to be
controlled is the starting time of data reacording, which I have to
work on it....by running up and down stairs to where the measurement
takes place to see the approximate time I get to it.
I started the sunlight-activated-sample measurement about 5:05 pm. I
activated the sample with sunlight for 2 minutes, and the running time
was 45 seconds. Dr. Noe will stop the reading taking in 2 hours, which
will be about 7:05 pm. I will then compare the datas between this one
and the very first measurement I did tomorrow.
I prefer to take a
thorough measurement again tomorrow though, with a actual timing and
longer activation time.
9:20 pm, I came back from my class, and I saw thr RS meter is still
running. I guess the sunlight is really a better source to activate
the sample. However, what cause it to have a longer glowtime, though?
what property does the sun have to make the glow last longer? Another
question is...Is there a maximum intensity for the sample hold or the
sample can hold as much intensity as the sunlight can give...I guess I
have to find out.
The meter reading is 1.4 mV now. I don't know if I should terminate
the reading, because I was stupid enough to forget to check the
initial background light the meter reads before slide the sample
I was trying to look for information about the characteristics of an
incandescent light and the sunlight. So far, I only learned about that
incandescent light is produced by a tungsten filament which glows in a
visible light when it has a very high temperature caused by the
electricity going through. Hm...Just realized...maybe everyone knows
what a incandescent light means except me... By doing research here, I
am also learning English a lot. I think it's helpful even though it
may appear to look like that I am stupid. It's not I don't know...it's
just I don't know the English vocabulary for certain
things. Anyway...I guess it's gettinglate, and I am too tired after a
whole day of class and working....@_@ I will take another reading, and
open another file at 1:00 am and then I will leave it on, maybe I will
come back in the early morning to check on it.
Tuesday, July 16th, 2002
I am working on analyzing the data I took with the
sunlight-activated-sample today. I have several very large files to
work on...I guess I won't be able to sleep tonight. Also I have to
write out an abstract, too...Hm...I am tired...
Wednesday, July 17th, 2002
I have worked on my 6 files of data, which contains thousnads of
readings that I took in the 18 hours. I have fixed the bad data, and
take the data average over time interval. The time interval I took for
averaging the data is for the first 10 seconds, I record the data
exactly; for the data between 11 - 100 seconds, I average evrey 10
seconds; for data between 101 - 1001, I took average every 100
seconds, and so on. Every time interval, I took 1/10 of the maximum
data number to average to get a best fitting line. Luckly, I got a
graph of the averaged data that fits perfectly well to the actual data
for each file. I am working on my 4th file of data now. I haven't
check on the last file, which contains almost 1 mg of data.... Since
it's too big,. I have to break it down to smaller files, and then do
the same analysis on the break-down files. Hopefully, I will finish
everything by tonight, so I will have time to work on my abstract
I accidentally changed the intensity of one of the data file this
morning, so I ended up spanding extra time fixing the file to what it
sould be. It was because I forgor to deduct the background light
intensity from the readings, and I wanted to subtract the value. As I
copied down the cell to the who sheet, I forgot that I didn't have a
formula for the intensity, so it ended up to cope the first cell to
the whole columnm and it was a straight line on the graph. Therefore,
I fixed that file, and still two more files to go...Hope my nearsight
doesn't get worse by staring at the computer screen all day long!
Problem raised when I was trying to average the data with a larger
interval. The data couldn't possibly show 10000 data in one file since
we cut the experiment to several files, one file contains data that
belongs to other file as well. Maybe I will try to separate the
interval to a smaller one.
I have finished the averaging work on the first 5 files, and I have
copied the last file, which is the largest one onto a floppy disk. I
will come back tonight and work on the splitting file, and also my
abstract. The graphs for the first 5 files look very neat. Since the
time interval can't be cut into 10000 intervals because of the data, I
used 1000 second intervals to average after 100 seconds, and it worked
out very well. I will print them out so I have a sense how the whole
graph look like. I will also put them on the web after splitting the
files into smaller pieces. and organize it.
Thursday, July 18th, 2002
In the morning, the files were splited to t smaller size files, and
the smaller files could be imported to the spreadsheet. Basically,
what I am doing now is to average the data over a time interval on the
spreadsheets again. This wouldn't take too long I think.
I have finished fixing and prganizing and averaging the data over
1000s time interval. So right now I have 10 files of data, and I will
be working on my abstract tonight. I will probably coming back from my
class later to finish up everything I am doing. I don't think I will
get a good analysis on the sunlight-activated-sample graph, but I iwll
do my best and thinking of a way to explain it.
Friday, July 20th, 2002
I was working on writing my abstract this morning. I think I didn't do
a good job on that, though....As always, my writing skill is
terrible. I couldn't quite organize my thoughts today...I think it's
the weather...Anyway...I will be working on my report as well this
I am thinking about how to write my report, but I don't know how to
organize my thought in a way that's coherent and logical...Considering
me taking a class about logics for a month...maybe that should help a
little. I saw Brendon is writing his report almost to the end...Hm...I
have to work on it as well...Hopefully I will write out a descent
report without missing anything, or talking about too much detail on
some irrelavent things....
Monday, July 22nd, 2002
The deadline of abstract is today, so I was rewriting and discussing
my abstract with Dr. Noe today for a very long time. I came in the lab
about 8:00pm again, because I didn't want to be in my calc 2 class,
the instructor is boring, and I took the quiz, which I am confident to
get 100 on it. Therefore, I rather to be in the lab working on my
abstract than staying in the boring class. Anyway, I have also ploted
the modified hyperbolic formula to my very first graph, it fits very
well. I have also plotted the averaged data on a new spreadsheet,
called sunlight.wq1. I plotted the function of 1/t^n, but I found out
the exponent n in this graph is not 1, it's 1.08. I don't know if it's
a good or bad result on this measurement. Since there are new things
coming out, I guess there will be a little change on my abstract,
too. In addition, I still have to prepare my presentation, and a
report for the REU talk...Time really flies....
Alright...it's very late now, almost 11:00pm at night, I better get
back to my room....so I can wake up early for the Brookhaven trip
Tuesday, July 23rd, 2002
It's the Brookhaven trip today, so we didn't come in to the lab until
After coming back from BNL, I was working on the
spreadsheet to get the graphs to be clearer, and fits better. I found
out that if I changed the numbers of constant values a little, I can
get a better-fitting graph. For the sunlight measurement, I plug in
the fitting line as a function of 1/(a+t^n), where a = 0, and n =
1.21. The exponent is a little bit high. The initial graph, I use the
same hyperblic format of formula, and its a value is 1, and the
exponent n is .96, which is .04 off from 1. Mm...I haven't discussed
with Dr. Noe yet, but data should be fine to present on Thursday.
Friday, July 26th, 2002
Today is Friday, but Dr. Noes said that we can have a day off. Its helpful
to have this day off, because I was sort of sleepless this passed week. I
have been worked on the REU presentation like eveyone else in the lab, and
presented on Thursday, July 25th, to the whole summer REU group. I think
it was fine, well....I guess it had to be fine, because I even worked till
2:30 am the night before with Jen. It's the latest I have stayed at work
for the entire life so far. I guess it's a usual routine for most of
scientists to work late, which means I will have to get used to it if I
want to be a scientist. Hm...sleep is very important though...tough
decision..."To be or not to be, that's the question." (Haha...=P) The
presentation went well, even though I was so nervious about, especially my
speech, thank God no one asked any tough questions that I didn't know how
to answer. First show in Ameriaca...That was good! Quite an experience
I have also put the links up on the web, so people can check out my
Monday, July 29, 2002
kids are all excited and active (well..maybe they are everyday, just
that I didn't notice...=P). I am looking for information about why the
sun light can make the phosphorescent sheet decay longer, and I am
also thinking about how to take another measurement on the
temperature. If using the cup-warmer, I will need a thing to measure
the temperatures, too. Well, even after the presentation, there are
still a lot of things to do. Hopefully, I will find something new and
cool in the next 3 weeks.
The high school intellegent kids were giving a talk and demonstration
to their Simon's Fellowship group in the center today. It went well, I
think. Hillary's thin film didn't work too well when she was
demonstrating. I was trying to help her with it, too. I think it's a
very interesting topic that she is doing, and I found out it take the
water dripping speed and the concentration of the soap to control the
quality of the thin film, it's very interesting. She should make t he
thing shorter though, it would be easier for her to add soap on the
The bleaching effect is still a mistery for us, and I don't know if
Evan is going to do a project on it, but I certainly will look into
the reasoning of it. It's very interesting that I thought that
stronger sample would show the bleaching effect more, but it was
actually the weaker sample, which is the one containing zinc
sulfide. In addition, it's more obvious if a red laser is shining on
it. I guess it has something to do with the wavelength and the
properties of the laser and the phosphorescent sheet. I will look into
it if I have time after I figure out the procedure and take another 2
measurements on the samples with the ideas Dr Noe and I came up
July 31st, 2002
I am trying to figure out how the spreadsheet program works so I can
analyze the data faster and more organized. The format of how to
average the data is the same as the method I used in the sunlight
data, which is to average the data over a time interval. However, this
time, I will average the meter reading for every 1/2 of the
interval. For example, if I can a 10 second reading, I will average
every 5 seconds.
The RS meter program allows data taking for a long time, but the
spreadsheet doesn't, it can only hold up to 8000 rows of
data. According to the discussion yesterday, we should take the
reading every 10 seconds, however, is that necessary to take the
reading every 10 seconds or so and then average them again? Will the
data analysis be accurate this way?
To adjust the resistance changes the sensitivity of the meter reading,
so I guess that's also the reason the sunlight data took a much longer
time to decay, because the sensitivity of the meter is higher.
Before trying out the new measurements, I want to have a good setup on
the side somehow, so that I can repeat my measurements faster and more
accurate. It would be good for my measurement on different
activations. The only thing that I am concerning about right now is
the decay time of the samples. If the samples take a very long time to
decay after activation, and I need 5 different set of measurements,
it's going to be time-consuming. I wonder if there is a way to make
the samples decaying faster....
The other question Dr. Noe thought about the other day was that what
if there is still light in side the sample before it's activation,
what effects will it have on the sample? Well, this is a simple
question I think. It's only effecting the activation time for the
samples. Let's say if the sample takes 2 minutes to activate fully
under sunlight, but it will be 1 minute and 30 seconds to activate the
sample assuming there is still light trapped inside. Plus, we came to
the conclusion that the sample never stops glowing, so there will
always be light in the sample, just the amount of light matters.
I was playing with the equipments this afternoon, and trying to make
sure everything is working so I can do another set of measurement as
soon as possible. I also read about the RS meter user's manual, and
how to change the time interval that the meter takes readings. There
is a problem about the resistor, it's not a stable resistor that I am
using, and I couldn't find any stable resistor for 10 mega ohm
resistor. If the resistor problem is sloved and I have gathered
the light sources well, I can start my measurement as soon as
possible. The light sources that I am thinking about right now would be:
- Incandescent light.
- Fluorescent light.
- blacklight(ultraviolet light).
- Laser light.
- sunlight(which will take a much longer time to decay)
These are the ideas of light source I have so far, I think I will
perform the sunlight measurement at the very end, since it's hard for
the samples to decay back to ~1 intensity. Since the triplet-singlet
state is "forbidden", I guess I will just have to wait for the light
decay back for every measurement. Otherwise there won't be any other
that I can think of to make the samples decay faster.
Just had a feeling that the hard part of being a scientist is the
preparation and the analysis of the experiments. The experiments is
the easier part of being a scientist. No wonder why a lot of
scientists have white hair even when they are still in their 30 or
40's, because they use too much brain power....(Will I have white hair
soon? Haha....hope not...I will try not to think too much
Thursday, August 1st, 2002
I was working on the resistor part, testing if the resisitance will
have a big effect on the sensitivity of the meter. I tested the
sensitivity on a unactivated sample for both 10 mega ohm and 1 mega
ohm resistor. The meter reads 0.1 mV on the 1 mega ohm while it reads
1.7 to 1.8 mV on the 10 mega ohm, it's about 20 times difference on
the intensity of the sample.
My questions comes up again, should I use a smaller resistance for the
measurements or should I use a larger one? The benefit of using the
larger resistance is that the meter is more sensitive, but it takes
much longer time to decay back, and it's the reverse for the 1 mega
I guess I will use the 1 mega ohm for different light sources
measurements, it will take a faster reading; and 10 mega ohm for the
longer experiement, which gives more sensitivity.
I was working on making a series connection of the resistors to get
the most accurate resistance for 10 mega ohm. It was about .30 mega
ohm off from the 10 mega ohm resistance on the sunlight
experiment. This time, I am able to make a 9.99 ~ 10.01 mega ohm
resistance, which will be a little more accurate on the
I don't know when is Ken going to be done with the DOS computer, so I can start mine soon....
Little thing on the side....
Last night I was talking to my friends online and I sent my webpage to
them to read about. As soon as they enter my page, they made comments
on the picture on my homepage, which Dr.Noe took for me long time
ago. They said: "Jill, change the picture on your homepage, you look
so fat on this picture!" I was so upset when I hear this...maybe I
should ask Dr. Noe to retake a nice picture for me and change the one
on my page now...=(...sigh....
Friday, August 2nd, 2002
The high school kids went to the Brookhaven Lab this morning, I guess
they had fun there, too.
I talked to Dr. Noe about the resistance, and also the light problem
that I have, but yet solved when I came in. I had a misconception on
the resistance and the speed of light duration. The resistance doesn't
change the speed of light decay. Changing the resistance is only to
change the light intensity(the voltage), and the sensitivity of the
meter taking readings. Dr. Noe suggested me that I can just stop the
meter whenever I want to. I decided to stop the meter at 30 minutes,
so the intensity reading will be about 1% of the original reading.
Today, I was working on the setup for the measurement on comparison of
the 10 mega ohm resistor, and the 1 mega ohm resistor. It's a sudden
idea to do this measurement though, I think it would be interesting to
see if the intensity is really 10 times larger. The set up is hard to
make this time, because I want to make a mounting base that's stablely
holding the limelite, which is attached to a cord. I used tape to tight the photo detector and the limelite with the mounting base, I think if we can get thouse plato toy things to form a mounting base will be much easier and more stable. I will try to go to the mall, and look for it today I guess.
I also did a test run on the 10 mega ohm resistor and 1 mega ohm
resistor, I got the readings, but it doesn't look like that the 10
mega ohms one would produce a 10 times larger resistance than the 1
mega ohm resistor. The reading for 10 mega ohm resistor is 0.921 V,
and it's 187 mV for the 1 mega ohm resistor. It's kind of strange, but
I will work on it later, when I have a more stable setup.
Monday, August 5th, 2002
I worked on taking measurements today, I was comparing the intensity
on the 10 mega ohm resistor and the 1 mega ohm resistor. I found out
something interesting, which I don't understand though. I thought the
intensity I detect on the the 10 mega ohm resistor would be 10 times
larger than the one on 1 mega ohm, but surprisingly, it's not. It's
actually only about 5 times larger than the 1 mega ohm resistor. I
calculated, and recalculated, it's still 5 times larger. It happens
both on single readings and average readings. I don't know why yet,
but in t he mean time, I am taking measurements on the incandescent
light with the sample being activated about 5 minutes under light
source, and reading will last for 30 minutes. I will do the same
measurements with different lights for these few days. I will probably
take the longer reading next week.
I recorded the light till the intensity is about 1/10 of the initial
light intensity. However, I found out there is a problem with the RS
mter program such that it doesn't record from the very first second of
the sample. The RS meter program usually flips so many pages because
of "OL" message it shows the "OL" message so many times, that when it
finally stabllized, the light intensity it record for the first is
about 20 seconds later than the activation.
Tuesday, August 6th, 2002
I am starting the second measurement on the various-light-sources
experiement. The sample was exposed under blacklight for about 5
minutes, and then I take the readings with the RS meter program. Black
light is actually a ultraviolet light(UV light
), and it
has longer wavelength, which is at the the visible end of blue
light. Like the measurement I took yesterday, I activate the sample
for 5 minutes, and then tuck under the photodetector with a black
cover on the top. This measurement will also last for 30 minutes.
The set up for this experiment was described in my earlier journal
dates. The variable for this set of measurement is the light
source. There are still 2 or 3 more light sources I will have to work
with. I will analyze the data later on in the afternoon.
I found out something interesting, the sample is activated very fast
with blacklight, it turns to bright shining green emitting light in
less then 10 seconds. It may also be that since the black light is a
violet color, so it's visible when I activate the light in a dark
room, because green and violet lights are not too similar. Yet by
using the incandescent light or the fluorescent light, since it
brightens up a larger area of the room, the speed of the sample
charging up is not that obivious.
Another interesting phenomenon, for little pink alien key chain
changed color after it's exposed to the blacklight. The color changes
from light pink to dark purplish color. It also emits a very tiny
yellowish light. The green alien only emits a very bright green light
after it's exposed under the black light, but it doesn't change colors
like the pink one. It's very weird, but interesting...I will ask
Dr. Noe about it later.
So the little pink alien toy emits light (it fluorescences) when it's
exposed to a blacklight, it probably is because it's absorbing some
other substance from being exposed to light. The other toy has the
same effect, too, but it brightens up, which the light emission is
much more visible.
I also did the measurement on fluorescent light, it's very obvious
that for the same amount of time of light exposure, the sample doesn't
get as much light as other light sources at the initial reading. It
might the the reason that the sample was not put directly on the top
of the light tube, such that it doesn't get as much light, according
to the inverse square law. I will try to see if I can get one light
tube down so I can put the sample on top of it.
I decided to add one more light source, which is the sodium light to
activate the sample before taking readings. Sodium light is a very
strong light, I think it would give the sample more energy, too
Wednesday, August 7th, 2002
Tina Shih came to visit, and gave a good talk with the delicious
pizzas =) Mm...Yummy! I was working on the measurements again, which I
used the sodium light to activate the sample. However, I didn't take
the cover off the sodium light, so the light intensity was very
little. Therefore, I redo it again with the sodium lamp cover off, and
activated the sample for another 5 minutes, and the initial intensity
is 300 something mV, and I think it's more reasonable.
I will work on laser light and probably sunlight also tomorrow, if it
doesn't rain. So far, the light intensity starts off the best by using
the blacklight and the incandescent light. That was Hillary's question
when I finished my activation with sodium light.
Thursday, August 8th, 2002
Today is the Father's Day in Taiwan!
Happy Father's Day, Dad!
I am looking for informations about sodium light on the web this
morning. I kinda get the idea what's going on in the lamp, but I want
to know more about it. I think I should talk to Evan about our
projects sometimes, because our projects are very similar. I also
think his project is interesting, if he is coming back, I am thinking
doing a project with him.
Monday, August 12th, 2002
It's the last week of the summer research. I don't think I did much this
summer, well...there are still some measurements that I need to
take. Towards to the end of this summer, I feel like I am in a rush of
doing everything, I have to finish the measurements, and I have to prepare
my final, and also moving back home...feeling a little tired...about
everything, and I am so lucky that I got a cold now in a hot summer
weather....Actually, I don't know how far my project can lead me to....
I talked to my dad and my friends about my project, they all said that
it's a very good project that I am doing, and they always gave me
suggestions and being very suportive.
A little bit tired, it's probably because of the cold. Even Jen asked me
if I am OK when she saw me today, I guess my voice really sounds horrible
or something...haha...Just kind of don't understand how a person can catch
a cold in the summer.
About the sodium light...Actually, about every kind of light source that I
used for my measurements, I don't really understand the difference between
each one of them. Incandescent light, sodium light, ultra violet light,
sunlight, fluorescent light...as I was doing my measurements, they all did
one thing, which is charge up the samples to the sample's maximum
strength(I guess)...I haven't done the analysis of different light
sources, but I think they should all look the same(similar)....
I will read more information different light sources today...Also trying
to find of anyone did similar project as I am doing now.
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