Daily Archives: February 7, 2011

Fermions and bosons 2

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Composite particles (such as hadrons, nuclei, and atoms) can be bosons or fermions depending on their constituents. More precisely, because of the relation between spin and statistics, a particle containing an odd number of fermions is itself a fermion: it will have half-integer spin.

Fermionic or bosonic behavior of a composite particle (or system) is only seen at large (compared to size of the system) distance. At proximity, where spatial structure begins to be important, a composite particle (or system) behaves according to its constituent makeup.

— Wikipedia on Fermion

2011.02.07 Monday ACHK

Job: Marketing

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Ever wonder what the difference is between sales and marketing?

The official definition is that marketing creates demand, while sales fulfils demand.

– Joel Spolsky

— Me@2008.03.26

— Me@2011.01.31

2011.02.07 Monday ACHK

Aircraft

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One of the mistakes novice pilots make is overcontrolling the aircraft: applying corrections too vigorously, so the aircraft oscillates about the desired configuration instead of approaching it asymptotically. It seems probable that investors have till now on average been overcontrolling their portfolio companies. In a lot of startups, the biggest source of stress for the founders is not competitors but investors.

— Paul Graham

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2011.02.07 Monday ACHK

CKY 2.1

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這段改篇自 2010 年 4 月 30 日的對話。

每題對應應該用多少時間，你要知道。一分的分數，價值多少分鐘的時間？

…

整份卷有兩個半小時，即是多少分鐘？

（CKY：150 分鐘。）

分數就共有 110 分。

150 分鐘 / 110 分 = 1.36 分鐘 / 分

即是每一分價值 1.36 分鐘。方便起見，我們假設每一分價值 1 分鐘。

（CKY：哈哈。老師，你說得很理想。 1 分鐘又怎能完成 1.36 分鐘的題目呢？）

有什麼問題？「1.36 分鐘」不是很難思考嗎？例如，某一題的分數是 4 分，對應的時間是多少分鐘？

如果用「1.36 分鐘 / 分」的話，你不能馬上知道答案。考試的時間非常緊密，不應製造任何令自己分神的事情。還有，當正式的時間分配是「1.36 分鐘 / 分」，而你卻用「1 分鐘 / 分」來盤算計劃的話，你就不知不覺地儲存了很多後備時間。

— Me@2011.02.07

2011.02.07 Monday (c) All rights reserved by ACHK