Supercontinuum light

is produced by a single frequency laser going through a fiber with non-linear interation.  the interesting part is the intensity modulated refractive index that changes the pulse phase and introduces the continuum.  See this article for details.  The efficiency is likely low enough and can not be used for LCD panel lighting. But may be useful for communication if the size can reduce from showbox to a mini card.  But it is an interesting reading anyway.

test

this is a test

Yang's 8g

not about him, but about other physicists.

projective geometry

read a nice talk by Dirac on projective geometry. Get the basic idea, but not sure why it is better than Euclidean Geometry.

Why does mirror flip the left and right, but not the top and bottom ?

The answer is it does not !

What mirror does is to change the longitudinal coordinate, but not the lateral ones. Let's say the mirror is place in x-y place, at origin z=0. Then any point at coordinate (x,y,z) will be mapped to (x,y,-z). Only the longitudinal coordinate z is changed. If you stand facing a mirror and place an object between you and the mirror. The closer to you the object is, the further away is the image. The object to the left is still to the left, same goes with right, top and bottom.

Now, if you wear a T-shirt, with a word on it, let's say, it is "TOYOTA", in the mirror, you will read "ATOYOT" on your shirt. And that is where the "rumor" of "flipping" comes :-) In fact, the mirror did not change the left to right. When you wear the T-shirt, from your perspective, the letters are indeed ATOYOT, reading from left to right; only that you can not see it easily without a mirror. One can verify it by pulling the T-shirt up by the collar, when the letters are at the eye level and the T-shirt fabric is thin enough, you will see it. What the mirror did is to move the letters longitudinally, so you can read it easily.

Advil

The thanksgiving holiday proved to be a mixed blessing. While Yan came over, we have to spend most time in the lab debugging the microcode. Worst yet, I caught a flu bug, as confirmed by how fast my doctor walked me out of the office today. He is prearmed with a standard pamphlet on flu FAQ when he walked in, and returned all my questions with a reference to the sheet. like what I should eat drink etc. To be fair, he did looked at my throat and listen to the lung. He suggested that I rest at home for 3-4 days. When I left, he did mention "it is highly contagious".

After the confirmation of the bad news and seeing the temperature soaring to 103.6 later, I went out shopping for chicken soup and advil, the standard flu supply. The Walgreen's advil range from 24 tablet to 100 tablet with various additives, but the main ingridient is the 200mg ibuprofen. the expriation date are all around 09/09. That probably means the bottle of Advil I had at home was bought about 1 year ago. I pick up a generic brand and quickly swallowed 2 tablets.

Then I went to Costco to pile up on the energy supply. For 3 days of liquid intake, I am budgeting 6 liters total, one gallon juice (there is a half-gallon at home) and another package (2 cups) of shrimp soup. To keep a steady supply of the protein, a 24 pack of yogurt is added to the shopping cart. Before leaving, I stopped by the medicine counter, found the Advil rack, the bottle contains 700 tablets and good till 03/11.

After carrying all the supplies up the stair, I felt the sweat and relief. That is only 1 hour after I pop in the Advil. Curious on the drug effect, I searched the ibuprofen drug data. Sure enough, the peak serum concentration is reached in 1 hour and the half life is about 2 hours. That is probably why the directions says every 4-6 hours.

by 4:30 pm, my temperature is already normal. And I am feeling much much better. Long live the Advil!

this is a test

Here is a test blog, i.e. the "Hello World" program.