# S-duality

In theoretical physics, S-duality (also a strong-weak duality) is an equivalence of two quantum field theories, string theories, or M-theory. An S-duality transformation maps the states and vacua with coupling constant g in one theory to states and vacua with coupling constant 1 / g in the dual theory. This has permitted the use of perturbation theory, normally useful only for “weakly coupled” theories with g less than 1, to also describe the “strongly coupled” (g greater than 1) regimes of string theory, by mapping them onto dual, weakly coupled regimes.

— Wikipedia on S-duality

2010.07.01 Thursday ACHK

# Rinus Michels

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Marinus (“Rinus”) Jacobus Hendricus Michels (9 February 1928 – 3 March 2005) was a Dutch football player and coach who was named “coach of the century” by FIFA in 1999. He played his entire career for the club Ajax Amsterdam, whom he later coached, and was a member of the Netherlands national team both as a player and as manager.

Michels became most notable for his coaching achievements, having won the European Cup with Ajax and the Spanish league with Barcelona, and having had four tenures as coach of the Netherlands national team, whom he led to reach the final match of the 1974 World Cup and to win the 1988 European Championship. He is credited with the invention of a major football tactic known as “Total Football” in the 1970s.

— Wikipedia on Rinus Michels

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2010.07.01 Thursday $ACHK$

# 選圖三部曲

Choosing a graph 3

1991-CE-PHY II-7 b

Constant force –> constant acceleration –> kinematic equations

1. 寫下一條方程式，連繫起 x-軸 和 y-軸 的 variables（變量）。

3.1 如果是直線的話（），看看 m 是正還是負，就可以知道那條直線的斜率（slope）是正還是負，因為 m 本身就是代表斜率。

3.11 m 正的話，那條直線就是向右上發展的。

3.12 m = 0 的話，那條直線就是一條平線。

3.13 m 負的話，那條直線就是向右下發展的。

3.2 如果是拋物線的話（），看看 a 是正還是負。

3.21 a 正的話，那條拋物線就是向上張開的（open upwards）。

3.22 a 負的話，那條拋物線就是向下張開的（open downwards）。

— Me@2010.07.01