ichris.ws - Science

Chance for a finite Erdős number

chris — Sun, 21 Jun 2009 16:05:10 +0000

A Game Theoretic Approach to the Toilet Seat Problem

chris — Mon, 06 Mar 2006 10:06:22 +0000

Brilliant real-world analysis with sound axioms. Von Neumann would have been proud.

First, I thought it was similar to The Journal of Irreproducible Results, but The Science Creative Quarterly is actually solid in its sciences. Of course, it’s the applications that count. In this case, it boils down to this approximately optimal algorithm:

In the morning John leaves the seat up after performing #1.
In the evening he puts it down.

Hawking

chris — Thu, 05 Jan 2006 06:24:44 +0000

Last night I watched Hawking on Hallmark Channel. It was released in 2004, but I have never heard of it until now, not surprising for a british film in Bangkok.

People will see this and think of A Beautiful Mind. Hawking and Nash were both prodigy in their field, but to me that’s where the similarity ends. Nash’s mind was hardly beautiful, and his achievements were driven in a large part by his pursuit of glory. For Hawking, it was the excitement of understanding, and the beauty of structures that inspire.

And the cinematography and scores had done well to portrait this frail man whose inside burns with love of physics and one women. The part I like most is when it finally struck him that singularity and big bang can be the same thing. The young hawking jumped off a train and, on the platform’s ground, drew diagrams showing the idea to his friend Roger Penrose. When he finished writing the results up, he walk out of his Cambridge hall a triumphant man. It’s the feeling of achieving something important that grip me.

Talking about Penrose, he’s one very cool person. (And he still is the last time I caught a glimpse of him in Oxford in 2000.) Other notable physicists in the story are Sir Fred Hoyle and Penzias & Wilson. Thought I like how they tied in the CBR right from the beginning, unveiling it bit by bit, I’m not sure the general audience will share the same idea. It’s quite confusing if you don’t know why the story always jump to this german guy giving TV interview.

In conclusion, (as a good physicist should always make) it’s a good movie. I recommend it.

Journal Following with RSS

chris — Fri, 18 Nov 2005 08:40:14 +0000

Each IEEE journals and conference proceedings now has RSS feeds that you can subscribe to. The feeds contain titles and abstracts, and are going to make my life that little bit easier.

Example: IEEE Photonics Technology Letters

IEEEXplore: Guide

Quantum Dot LED for Efficient White Light Source

chris — Wed, 26 Oct 2005 16:19:46 +0000

The finding at Vanderbilt University has got many publicity this week, in the wake of global high energy price.

The technique is based on a certain specie of quantum dot called magic-sized quantum dots. What this means is the dot size is naturally preferred, and thus easy and fast to grow. (In the case of Cadmium Selenide, it is 33-34 atoms in a dot.)

Taking in radiation from a blue LED, these quantum dots emit light in the 420-710 nm range, which cover a large portion of the visible spectrum. (Source other than blue LED will not change the output spectrum, a nice feature) More importantly, the energy distribution is not too different from sunlight, which means it better suits our eyes compared to fluorescence. The fact that it doesn’t emit infrared means the ‘bulb’ can be cool when operated, and we get more visibility per energy unit. (read: cheaper lighting)

What If Dragons are Real?

chris — Mon, 03 Oct 2005 07:47:48 +0000

No, it’s not that kind of what if? question. I’m talking about a technical exploration of the features and evolution trails of dragons, on the hypothesis that they did exists. (It’s not that much different to many real life science, mind you.)

I just finished watching Dragons: Fantasy made Real on pay-per-view in my hotel room, and it was worth the money.

It was very well made, and not surprisingly nominated for this year’s Emmy in outstanding animated program category, only to be pipped to it by Clone Wars Volume 2.

In this imaginary scenario, dragons belong to a line of dinosaur with a special feature. Hydrogen deposit lungs that both enable them to be light enough to fly and breath fire. It’s far fetch, but not by that much. The gap with reality only widened when the program depicts the last survival dragon who lived until less than a millenium ago and died by humans hand in Romanian’s Carpathian mountain. But it’s insightful and entertaining nonetheless. And I don’t have to shut down the rational part of my brain like for 95% of the sci-fi stories out there.

A Quantum Love Story

chris — Mon, 19 Sep 2005 14:26:25 +0000

I just sent out one of those funny fwd: e-mail. It’s not very deep and I hope people will get it. But quantum entanglement and Alice & Bob are necessary background for the joke. So, in the end I only sent it to 10 peoples and hope at least 7 will understand. The world is a cold and lonely place for us physicist. :)

The content of the e-mail is this powerpoint file by Charles Bennet.

[ via Node of Yan Feng ]

Trackbacks for papers

chris — Thu, 25 Aug 2005 03:45:43 +0000

On his blog, Jacques Distler wrote of how arXiv.org e-Print archive starts to support trackbacks for individual articles. Which I think is very cool. Of course, we have systems that track paper citations, but one doesn’t always want to write another paper just to express comments about one. I might just want to say it’s a fabulous find, or simply crack.

I don’t really know how many physicists keep a blog (it’s more than mathematician or other kind of sciences anyway, to my knowledge. But this could, in theory, be implemented in greater scale. Say, a course webpage for a graduate class in quantum field, which sends trackback to articles that it discussed.

What I disagree with is the system that only allow incoming pings from white listed sites. This is really backward and, of course, not scalable, and there exists many spam protection that doesn’t require more than an hour a week to keep accurate. And for the crackpots? I don’t see any difference in them compared to viagra or poker spams. Just mark them as spams and let the system blacklist the site in the usual way. If it takes more than a few second to decide whether one trackback is crazy, it’s probably worth keeping.

Or am I being naive about the last point? Crakpots’ determination to voice their theory is sometimes as strong as sex drive.

Dihydrogen Monoxide

chris — Mon, 04 Jul 2005 11:56:44 +0000

Found this link on Ajarn Ko’s blog. The very harzadous yet not well known substance called dihydrogen monoxide. Amongst its attributes are:

Death due to accidental inhalation of DHMO, even in small quantities.
DHMO overdose is not unheard of in patients undergoing dialysis treatments for kidney failure.

Exposure decreases effectiveness of automobile brakes.

How has the world’s governments managed to keep this a secret? This is outrageous!!

Funny Review at Amazon.com

chris — Sun, 23 Jan 2005 14:02:32 +0000

These are great reviews, one by Steven Worley is fantastic. :D (warning: geek jokes)

[ via mathematics weblog ]

World Year of Physics 2005

chris — Thu, 30 Dec 2004 14:31:40 +0000

[textile]

:D Hahaha, I can hear the screams, “year of what?!?” I suppose that is exactly the reaction they would like this project to fix.

Their official website is here. I’m too busy right now to read their plan in detail, but I whole-heartedly wish the project to become a success. You see, I’m a physicist by training and profession, and any attempts to make that sounded more cool is very welcomed. ;)

I truely, madly, deeply like the subject. And the decision I made not to switch to engineering on my 2nd year of uni is one of the best decision I have ever made in my life. Physics never bothered me much in high-school, but it didn’t get me very excited either. That was until I was exposed to real physics. It’s beautiful, and wonderful, and I was much entertained in my 3 years at Mahidol’s Physics Department.

I took a detour afterward to enter the photonics field. (and took a fair share of bitching from my purer peer) That was largely a financial decision, as nothing beats fundamental sciences in the sense of logic & simplicity that it conveys. It is like talking to mother nature herself.

I used to do tutoring for a few years, not just for the money, but also because I think I’m a farily good teacher. I believe most people hate it because high school science teachers are crap. Nobody should have to remember hundreds of formulae to understand Physics. And nobody should have to be forced to learn it. We are already curious about it since forever! What’s out there in the universe? Why’s the sky blue? How come we don’t fall down if the earth is round?

side note Stephen Hawking was born on January 8, 1942, exactly 300 years since the birth of Galileo Galileo. And they were both great scientist in their time.

Einstein was born March 14, 1879, and Chris came to earth March 12, 1979. Another 2 days and it will be exactly 100 years. Coincidence? I think not.

Discovery's Top 100 Science Story of 2004

chris — Wed, 29 Dec 2004 06:48:32 +0000

My highlight from the list would be quantum teleportation at no. 9 and organic compound in space at no. 26. Strangely, the black hole information paradox-no-more is not in the list.

[link]

นานๆ ที

chris — Wed, 04 Aug 2004 17:31:28 +0000

[textile]

ไม่ได้ใช้ vcharkarn cafe มานานมากแล้ว เพราะหลังๆ มีแต่เด็กถามการบ้าน จะเข้าไปประชดก็ดูจะไม่มีใครได้้ประโยชน์

เมื่อก่อนเคยตอบเยอะ เพราะรู้สึกสนุกอยู่ บางทีไม่ได้รู้เรื่องก็ไปหาๆ มาคุยกับเค้า ขอให้ได้เขียน ว่างั้นเหอะ

เหมือนวันนี้

คลอโรฟิลด์ a สีเขียว เพราะดูดกลืนแสงช่วงม่วงแดงเยอะสุด

คลอโรฟิลด์ b ดูกลืนสีเขียวด้วยนะครับ ดูกราฟ http://en.wikipedia.org/wiki/Chlorophyll

จะพูดว่าคลอโรฟิลด์ a มีสีเขียวเพราะไม่ดูด สีเขียว เป็นคำตอบคำถามที่ว่า “ทำไม” มันสีเขียว แต่ไม่ได้ตอบว่า “เพราะเหตุอันใด” : )

อาจจะเพราะแสงสีเขียวมันมีเยอะสุด พืชเลือกใช้ความยาวคลื่นนี้จึงมีประสิทธิภาพที่สุด

เคยได้ยินว่า สิ่งมีชีวิตเกิดขึ้นในทะเลเป็นที่แรก จึงพัฒนาขึ้นมาโดยพยายามใช้ประโยชน์จากความยาวคลื่นแสง ที่ส่องทะลุลึกลงไปใต้น้ำได้ แสงสีต่างๆ ในช่วงที่เรามองเห็น ก็ถูกดูดกลืน(ด้วยน้ำทะเล)ได้คล้ายๆ กัน

http://oceanworld.tamu.edu/resources/ocng_textbook/chapter06/chapter06_10.htm

แต่เพราะเริ่มแรกมีแสงสีอื่นน้อยอยู่แล้ว ลงไปใต้ทะเลยิ่งแทบไม่มีสีอื่นเลยนอกจากเขียว

http://www.oceansonline.com/light_in_the_sea.htm

ไม่ได้อ่านละเอียดนะครับ link ข้างบนสองสามอัน ถ้าไม่ถูกต้องขออภัย : )
Dubber

แต่ก็รู้สึกดีนะ จะพยายามตอบให้บ่อยขึ้น ยังไงที่นี่ก็มีเด็กนักเรียนมากกว่า หว้ากอ ถึงจะบ่นว่าเด็กไม่ได้เรื่อง ก็ต้องพยายามช่วยๆ ให้มันดีขึ้น

Durian and Alcohol

chris — Tue, 27 Jul 2004 19:34:53 +0000

[textile]

I have heard it many times before, that eating durian with alcohols could be fatal. I was buying it, but not completely.

Today a guy name s.suk at wahkor explained the process, and it sounds plausible.

Q: ทำไม ทุเรียนกับเหล้า เกิด ไซยาไนท์

A: ในทุเรียนมี แอนโธไซยานิน เป็นเม็ดสี ซึ่งแอนโธ ไซยานิน นี้ ดิบ จะมี สีขาว พอ สุก จะมี สีเหลืองอำพัน พืชที่จะมี แอนโธไซยานินอยู่มาก ก็คือ พืชเนื้อสีเหลือง หรือ ม่วงแดง หรือ มียางสีขาว
พืชที่พบมาก เช่น ในใบมันสำปะหลัง น้ำยางโป๊ยเซียน ทุเรียน ห่าม (สุกแล้ว กลับลดลง) และ น้ำยางพารา
เมื่อแอนโธไซยานิน ทำปฏิกิริยากับ แอลกอฮอล์ จะแตกตัว ได้ ไซยาไนดีไฮด์ หรือ ก๊าซพิษที่สามารถทำลายการรับอากาศเข้าเส้นเลืด ในปอดได้่ พูดง่าย ๆ ว่า ปอดตาย

เคยมี เกษตรกร ไปขุดหัวมันขาย พอพักเที่ยงก็เอาเหล้าขาวมาดื่มกัน กลับบังเอิญ ทำจุกหาย ก็เลยเอาใบมันสำปะหลัง ม้วน ๆ แล้ว ยัดอุดไว้ พอเย็น มาเปิดดื่มอีก

ตายเรียบ

อีกกรณีนึง น้ำยางพารา จะทำให้แห้งเร็ว และเป็นรูปที่ดี จะต้องใช้ สารโคแอ๊กคูแลนซ์ เพื่อให้มันมีแรงตึงผิวเพียงพอที่จะก่อรูปทรง มี การทดลองงานหนึ่ง แทนที่จะเอา น้ำ มาละลายโดแอกคูแลนซ์ ที่ว่านี้ (ในที่นี้ ใช้สารโปแตสเซียม ไนเตรท เป็นโคแอกคูแลนซ์) จะเอามือจริง ๆ ลงไปจุ่มแทนแม่พิมพ์ ด้วยฉลาดแต่ขาดเฉลียว จะให้ สารโคแอ๊ก แห้งเร็ว จึงเอาแอลกอฮอล์ เป็นเบส แทนน้ำเปล่า
สลบกันเป็นแถว ดีนะ ที่ แอลกอฮอล์ เปอร์เซ็นต่ำ ไม่งั้นได้ตายกันมั่ง

Black hole information paradox

chris — Thu, 15 Jul 2004 20:26:49 +0000

[textile]

It’s been years (5-6) since I was into cosmology. And the last few subjects I was looking at was Hawking’s radiation and information paradox. Well it seems that very soon the paradox is no more.

Began as just a fascinating idea, popularized with a catchy name , and brought to the masses via many science fictions. Black hole, as most people know, sucks everything into it. It just gets bigger and bigger as more things falls inside. And nothing ever escapes.It is black because light cannot travel away from it and onto our eyes. That was the original idea.

But then Stephen Hawking proposed his idea of how “something” can actually escape from a black hole. With a simple mechanism of virtual particle pairs created at the surface (called event horizon), it can happen that half of the pair (with negative mass) falls into the black hole, and the other half (with positive mass) escapses. To us outside this will just looked like the black hole “emit” a particle and lost some mass. We call the particles coming out “Hawking’s radiation”. And we can actually see black holes because of their radiations. Some of them are quite bright indeed.

This is good news. So black hole doesn’t just expand and end up eating the whole universe. Actually most of them will spew out lots and lots of things when they get big enough. This is all and well, except there is a something missing. According to the then theory (sometimes called the quasi-classical theory), Hawking’s radiation are totally random. In other words, you cannot tell what fell inside by looking at what comes out of it. This bugs many people. Something is loss. The information.

Well, as with many cases in the history of Sciences. The solution that is good, but not good enough, can be improved on by the advancement of the theory behind. It was in the 70’s that Hawking thought of black hole’s radiation. And at the time, the universe still consist of point particles.

Now it is made of String . And with String Theory-based model of the black hole. Scientists had come up with a proof that the information is, after all, not lost. Mystery solved.

According to this article in New Scientist , Hawking himself also has a few word on this matter. To quote:

I have solved the black hole information paradox and I want to talk about it.

This is what he said to the chairman of the GR17 (the 17th International Conference on General Relativity and Gravitation, to be held between 18th – 23rd July 2004 in Dublin, Ireland). Now how do you say no to that? The chairman admitted he just went with the reputation and accpeted it.

I think I will stop here, I have already went in over my head. But it is a very fascinating story. And you can find out more at this excellent web page which tell the story nicely, with the dirty details if you are so inclined.