光吸收的物理学基础 本文是Brian Wardle: Principles and Applications of Photochemistry 翻译计划的一部分。本文选自第二章，为原文的2.3节。 可以吸收光的分子中含有天线基团，被称为 发色团 （ chromophores 或 chromophoric groups ），分子吸收光的过程主要由发色团完成。当振荡电磁辐射与合适的发色团相遇时，发色团中的一个电子可以跃迁到能量更高的激发态，发生这一过程的前提是光子的能量与电子跃迁前后两个量子化能级的能量差相匹配。发生电子转移时，吸收光的发色团发生 电子偶极跃迁 （ electric dipole transition ），光子的能量变成整个激发态分子的一部分。 跃迁偶极矩 （ transition dipole moment ）只存在于跃迁发生的过程中，跃迁偶极矩产生于电子的移位。吸收的强度与跃迁偶极矩的平方成正比。 研究分子的光吸收过程时，首先应探讨电子状态之间的转变。然而，不考虑到核的运动就不能完整地讨论电子激发效应。 因此，分子的总能量包括电子的能量和核运动（振动和转动）的能量： E t = E e + E v + E r 其中下标分别表示总能量、电子能、振动能和转动能。由于电子能、振动能和转动能有较大的差别，因此假设可以把它们分开讨论。这个假设被称为 玻恩-奥本海默近似 （ Born–Oppenheimer approximation ）。 电子状态能级之间的能隙比振动能级之间的能隙大得多，而振动能级之间的能隙又比转动能级之间的能隙大很多。因此，在研究分子内电子转移效应时只考虑量子化电子状态能级和振动能级。 分子吸收紫外和可见光后引起电子跃迁，同时涉及电子能级改变和振动能级改变。这种跃迁称为 振动跃迁 （ vibronic transition ）。 在热平衡条件下，各个能级的数量服从 波尔兹曼分配定律 （ Boltzmann distribution law ）。如果基态分子数为 N 0 ，那么较高能级分子数 N 1 可按照如下公式计算： N 1 / N 0 = exp( -Δ E / RT ) 其中exp为指数函数（计算器上的 e x ），Δ E 为两个能级间的能量差， R 是气态常数（值为8.314 J K -1 mol -1 ）， T 为温度。 波尔兹曼分配定律的计算结果说明：在室温下，大多数分子处于电子基态的 v = 0振动能级，因此分子的光吸收多从 S 0 ( v = 0)态开始。（图2.2） 图2.2 有机分子基态、最低激发态及其量子化振动能级示意图。竖直箭头代表光吸收引起的振动跃迁 图2.3给出了双原子分子的势能曲线，通常称为 莫尔斯曲线 （ Morse curve ），该曲线描述了随着分子内键长的改变，分子势能的变化情况。 图2.3 双原子分子的莫尔斯曲线，其中水平线表示量子化振动能级。曲线最低点为平衡键长， r e 水平线与莫尔斯曲线交点处，能量全部为势能。而在点和点之间，能量部分为动能，部分为势能。 每个振动能级都有对应的波函数。给定一个振动量子数 v ，波函数的平方则可表征该振动能级与核间最可能的距离。图2.4为一系列振动量子数的振动概率函数。在 v = 0能级下，波函数的平方说明分子最可能处于平衡构形下。然而，对于激发振动能级来说， ψ 2 函数的大小最接近振动能级的转折点，这说明键最可能处于全扁平构形或者全伸展构形。 图2.4 一系列振动量子数的振动概率函数。请注意v越高，分子键长越可能在莫尔斯曲线附近的两个极限处；另外，对于任一 v 值，都有 v + 1个极大值点 核比电子重得多，运动也慢得多，电子跃迁到另一个能态的过程花费的时间很短，可以认为在这一过程中，原子核为固定不动的。这一假设称为 弗兰克-科顿原理 （ Franck-Condon principle ），因此，电子跃迁的过程可以用图2.5中的垂直箭头表示。也就是说，电子跃迁过程中，原子核框架体系是“不变的”。所以，分子吸收光子引发的电子跃迁也称为 垂直跃迁 （ vertical transition ）或 弗兰克-科顿跃迁 （ Franck-Condon transition ）。 当两个相邻电子能级的核间分离程度类似时，其振动能级的跃迁强度最大。也就是说，相邻电子能级的振动能级的 ψ 2 函数重叠越大，越容易发生电子跃迁。该重叠叫做 弗兰克-科顿因子 （ Franck-Condon factor ），如图2.5所示。 图2.5 S 0 ( v = 0)态吸收光子后最可能发生的跃迁：（a）两个电子状态几何构型相近时，曲线的最低点位置一致；（b）激发态的核间距大于基态
光吸收概述，朗伯-比耳定律 本文是Brian Wardle: Principles and Applications of Photochemistry 翻译计划的一部分。本文选自第二章，为原文的2.1和2.2节。 光吸收概述 所有的光化学和光物理过程都开始于对紫外、可见光的吸收从而产生激发态的过程。 R + hν → R* 高效的光吸收过程有如下特点： 光子的能量与吸收光子的材料的能级差匹配。 当初始波函数和最终波函数（ ψ 和 ψ * ）最相近时，吸收最强。 朗伯-比尔定律（Beer-Lambert Law） 不同物质吸收光的能力相差很大，吸收光的能力用 摩尔消光系数 （ molar absorption coefficient , ε ）表征。发生光吸收过程时，入射光的强度 I in 比出射光强度 I out 要强。光的相对吸收率（ I out / I in ）与吸收光的物质的浓度（ c ）和光程（ l ）成指数关系： I out / I in = 10 - εcl 两边同时取对数得： log ( I out / I in ) = - εcl 即： log ( I in / I out ) = εcl 等式的左侧称为吸光率 A 。吸光率，浓度，光程之间的线性关系称为 朗伯-比尔定律 （ Beer-Lambert Law ）： A = εcl 除非使用高强度入射光（如激光），朗伯-比尔定律是广泛适用的。光吸收过程中，相当比例的受照射粒子处于激发态而非基态。 由于历史原因，光谱学中使用的ε的单位通常为非SI单位。 浓度 c ，通常使用摩尔每升mol l -1 。 光程 l ，通常使用厘米cm。 A 是一个没有单位的对数量。 由于 A = εcl ，有： ε = A / cl 因此 ε 的单位通常为：cm -1 ×(mol l -1 ) -1 = l mol -1 cm -1 。 对给定物质来说，改变入射光波长，则摩尔消光系数也随之改变。用 ε （或log ε ）对波长（或波数）做直方图，得到的曲线叫做物质的 吸收光谱 （图2.1）。对光化学工作者来说，吸收光谱的首要作用是给出了某种化合物的最大吸收波长（ λ max ）以及在该波长处得到的最大摩尔吸光系数（ ε max ）。因此，在 λ max 处激发化合物可以得到最佳的激发效果。此外，朗伯-比尔定律被广泛用于测量物质的浓度。 图2.1 丙酮的吸收光谱
分子轨道 本文是Brian Wardle: Principles and Applications of Photochemistry 翻译计划的一部分。本文选自第一章，为原文的1.3节。 分子中的键合作用可以用一种叫做 分子轨道理论 的模型来解释。与原子轨道理论类似，量子力学模型也要求分子中电子的能量是量子化的。一类特定的波函数，即 分子轨道 ，可以描述这些分子的量子化能级。 为了最简便地检验分子轨道理论，我们可以仅考虑双原子分子。两个原子的原子轨道的波函数相互作用，产生两个新的分子轨道的波函数。（图1.4） 图1.4 两个独立的原子轨道（AO）相互作用生成分子轨道的过程（MO） 若原子核之间原子轨道波函数增强，则可得到能量较低的 成键轨道 。原子由于原子核和成键轨道中的电子互相吸引而连在一起，并且 ψ AB = ψ A + ψ B 。 若原子核之间原子轨道波函数减弱，则可得到能量较高的 反键轨道 ，反键轨道排斥电子， ψ * AB = ψ A - ψ B 。 如果形成分子轨道的两个原子轨道都是s轨道，那么生成的轨道分别称为 σ （ sigma ）成键轨道和 σ *（ sigma星，sigma star ）反键轨道（如图1.5）。 图1.5 σ （成键）和 σ *（反键）分子轨道的边界表面 如果形成分子轨道的是两个平行的p轨道，那么生成轨道分别称为 π （ pi ）成键轨道和 π *（ pi星，pi star ）反键轨道（如图1.6）。 图1.6 π （成键）和 π *（反键）分子轨道的边界表面 分子轨道的 相位 （表示为+/-）是波函数的符号。+表示在这一区域的波函数为正值，-表示这一区域的波函数为负值。 除了成键轨道和反键轨道之外，还有一种 非键轨道 （n）。这些轨道中通常包含着孤对电子，在原子形成分子过程中既不起成键作用，也不起反键作用，只存在于分子中一个原子中。非键轨道的能量通常比成键轨道要高。 图1.7所示为有机分子中量子化能级的简图。 图1.7 有机分子中分子轨道示意图 分子轨道模型也可以用来解释 d 区元素的络合物。与自由状态的金属不同，在八面体复合物中金属原子的 d 轨道并非是简并的，这是由配体和金属轨道间的相互作用造成的。五个 d 轨道分裂成三个 t 2 g （非键）轨道和两个 e g *（反键）轨道，即： d 区金属八面体复合物ML 6 的分子轨道如图1.8所示。这些分子轨道被分为成键轨道（ σ L 和 π L ）、非键轨道（ π M ）以及反键轨道（ σ L *、 π L *和 σ M*）。 d n 区金属的八面体复合物基态电子构型中， σ L 和 π L 轨道是全满的，同时， n 个 d 电子在 π M 非键轨道中以 t 2 g 对称的模式排列，在 σ M *反键轨道中以 e g 对称的模式排列。 图1.8 d 区金属八面体复合物ML 6 的分子轨道示意图。竖直箭头表示复合物吸收光子后可能引发的不同的电子构型转换过程。 分子吸收光子可使一个电子从已排布的轨道跃迁至空轨道，从而形成激发态构型。这些构型转换过程可分为如下几种： 金属中心（metal-certred, MC）构型转换，又称 d - d 转换，指的是金属中心的非键轨道和反键轨道之间发生的构型转换。这种转换通常发生在d区第一族元素之中。 配体中心（ligand-centred, LC）构型转换，指的是配体中心的成键轨道和反键轨道之间发生的构型转换。这种转换常发生在带有扩展 π 和 π *轨道的芳香配体之中。 配体向金属电荷转移（ligand-to-metal charge transfer, LMCT）机理的构型转换，指的是发生于配体中心分子轨道的成键轨道和金属中心分子轨道的反键轨道之间的构型转换。如果复合物的配体易被氧化，金属易被还原，则可发生此类构型转换。 金属向配体电荷转移（metal-to-ligand charge transfer, MLCT）机理的构型转换，指的是发生于金属中心分子轨道的非键轨道和配体中心分子轨道的反键轨道之间的构型转换。如果复合物的金属易被氧化，配体易被还原，则可发生此类构型转换。
A judgment experimental design about ofthe basic principles of Newtonian mechanics or the second law of thermodynamics LI WeiGang (Binjiang school, Ankang 725011, China) Abstract ： This article describesa similar Maxwell's demon experimental design. However, comparedwith the Maxwell's demon program, which does not requireMaxwell's demon that wisdom can work. Moreover, the program isn’t anideal experiment that can be performed only in thought; but can berealistic implementation of the experimental design. The design full compliancewith the basic principles of Newtonian mechanics, but can breakthrough thesecond law of thermodynamics. The experimental design reveals the existence ofa logical contradiction, between the basic principles of Newtonian mechanicsand the second law of thermodynamics. Keywords ： Maxwell's demon,The basic principles of Newtonian mechanics ，The Second Law of Thermodynamics，Logicalcontradiction. PACS ： 05.20.-Y, 05.20.Dd, 05.65.+B INTRODUCTION Since Boltzmann built up a bridge between the Newtonianmechanics and thermodynamics, the thermodynamics is reset to the Newtonianmechanics, after hundreds of years, people have become accustomed to think: theNewtonian mechanics and the second law of thermodynamics is logically self-consistent. But, really between Newtonian mechanics and the second lawof thermodynamics, it is always logically self-consistent? In this regard, Maxwell was skeptical. In order to discuss thelogical contradictions that may exist between the both, Maxwell design -Maxwell's demon - such a famous thought experiment. However, thisdemon need to work according to the information of molecular motion. Get information needsadditional energy consumption. Accordingto the modern point of view, Maxwell ideal experimental design, does notconstitute a challenge to the second law of thermodynamics. Can not be used asevidence there is a logical contradiction between the basic principles ofNewtonian mechanics and the second law of thermodynamics. Recent studies have found: There are an experimental design which do not need thatkind of wisdom of the demon. On the design, the conclusions that thereis a logical contradiction between the basic principles of Newtonian mechanicsand the second law of thermodynamics can be derived. The program, constitute ajudgment experiment on - Basic principles of Newtonian mechanics iscorrect, or correct second law of thermodynamics?. It has importanttheoretical and practical significance. If the judgment result of this experiment is that the basicprinciples of Newtonian mechanics is higher than the truth of the second law ofthermodynamics, thenthe design itself constitutes a human long-awaited first successful perpetualmotion machine of the second kind; Else if the judgment result of theexperiment is that the truth of the second law of thermodynamics is higher thanthe basic principles of Newtonian mechanics, then, in the field of physicsconcepts lead to a huge change. No matter how the final results, t heoretical studies and research on the implementationdetails of the program are required to vigorously promote. 1.Experimental Design As we all know – 1. The ball from one endof the U-shaped pipe injection can be emitted from the other end, ignoringfriction losses, ball momentum diminished; 2. Photons incident on oneend of the fiber, the photon can be emitted from the other end, the samefrequency (energy unabated); 3. As analogy, if there isa Narrow tube, one end of the molecule from a Narrow tube into the goal, themolecule can be emitted from the other end of the Narrow tube (kineticunabated, in theory, need only a Narrow tube close to the ideal rigid body); Then, when the Narrow tube sufficiently narrow (such ascarbon nanotubes), only allow a fluid around one molecule, as shown in Figapparatus In the initial state, although a fluid molecules 1, intheory, have the same probability of either end into the Narrow tubes 2, fromthe other side out; system can not generate macro kinetic energy. However, if applied an initial start-up process to thesystem, the system will be continuouslyproduce macroscopic kinetic energy (jet), from a single heat source; After theboot process, enter the work status, working status can be self-sustaining. Boot process can be: Pumping the fluid molecules into themain chamber, from confluence-tube spout 4, until the formation of the macrojet. Since we can choose a single atom of inert argon gasmolecules as working fluid; choose, rigidity can be comparable tothat of diamond, carbon nanotubes as Narrow tubes （Tsinghua University can already make up half a meter of carbonnanotubes）. So that the experimental design, be not an idealexperiment as if Maxwell's demon, but can actuallybe carried out. 2. A proof of the jet can beself-sustaining , based on the principles of Newtonian mechanics 2.1 A biasedcollision off-axis theorem proof , and consequence. Definition 1 : Any one of the moleculeA, before the collision centroid drift motion path called axis (of molecules A) ; The molecule A, theforward direction of the axis is called axialdirection (of the molecule A) ; Definition 2: Molecule A,along the axis of molecules A, collided with another molecule B, and the bothcentroid-connection in the axis of the molecule A, called the molecular A, bymolecular B positive collided; All other collisions, called biased collision. Theorem: When any molecule A, are biased collision by anothermolecule B, both two molecules A, B, will deviate from the axis of molecule A. Proof of the theoremfollows: ∵When biased collision, two molecules centroid-connection isnot on the axis of molecules A; ∴When biased collision, two molecules interacting impulsef *t，outside of the direction of the axisof the molecule A is not zero; ∴After the biased collision occurs, both two molecules A, B, willdeviate from the axis of molecule A. QED. Consequence: Because biasedcollision is much greater probability than positive collision, the moleculesout of the Narrow tubes, all is almost encountered biased collision. Makingbiased collision two molecules will deviate from the axis of the molecule whichleave out of Narrow tubes, have no chance to reverse into the Narrow tubes;Therefore, after the start, the probability, of molecules going into a Narrow tube from the two port, can be locked inan unbalanced state. 2.2 It is significant that Confluence Pipe locked at imbalance In the Confluence Pipe inside as shown, Thereare Narrow tubes outlet be setted. There are the consistency in the Narrow tube outletdirection and the Confluence Pipe outlet direction. Therefore, when the Confluence Pipe large aspect ratio to acertain extent, can be done – 1. The cross-sectionalarea of the outlet Confluence Pipe is smaller than the accumulate of allcross-sectional area of the Narrow tubes outlet. 2. In the vast majority ofcases, each molecular out from the narrow tube, into the Confluence Pipe space,collision will suffer from the other molecules being out from the narrow tube,into the Confluence Pipe space. 3. Collision, based on theNo.2 conditions, Bothsides have a momentum component pointing to the direction of outlet ofConfluence Pipe, therefore,such a collision, will not result in molecules going adversely into the narrowtube. 4. Based on the No.3conditions, it is possiblebeing a high density gas in the Confluence Pipe. However, it will be not formation of a negative pressuredifference, to deter automatic flow. 5. Based on the (No.1 toNo.4) conditions, it is a jet directed and high-density molecular flow out ofthe Confluence Pipe. Alarge number of biased collision, make it reduce to almost zero chance of, thatthe molecule reverse into the Confluence Pipe. 6. That is, the systemonce formed Auto Flow, which can never stop. 7. Particularlyinteresting is: If you set the impeller near the outlet of confluencepipe, make the jet acting on the impeller, so, after doing work, reducing the average kinetic energyof molecules. The “low kinetic energy of the molecules” concentrated relativelynear the confluence tube outlet, forming a relatively low temperature region. So that, in theory, acommon heat engine can work also where there is no condition making a commonheat engine work initially. 8. When the jet acting onthe impeller, the impeller driven generator, the energy output to the outsideof the system, the system temperature is reduced, the system can absorb heatfrom the environment. Means: a system which work in accordance with the basicprinciples of Newtonian mechanics, due to play a specialself-organization roles in the narrow tube and the Confluence Pipe,the system can continue to absorb heat from the environment, and theenergy with random motion ofmolecules can be poured into macroscopickinetic energy (constitute the second category perpetual motion ). Obviously,this is a direct violation of the second law of thermodynamics. 3 Conclusion The experimental design reveals the existence of a logicalcontradiction, between the basic principles of Newtonian mechanics and thesecond law of thermodynamics. References Tsung-Dao Lee,Statistical Mechanics Shanghai: Shanghai Science andTechnology Press, 2006.11 Lin Z H..Thermodynamics and Statistical Physics . Beijing UniversityPress, 2007
题目是Peter Schweizer的一本书的名字，异常的正确。作者通过研究很多知名政治家、社会活动家等等（如the Clintons, Nancy Pelosi, the Kennedys, and Ralph Nader; commentators Michael Moore, Al Franken, Noam Chomsky, and Cornel West; entertainers or philanthropists Barbra Streisand and George Soros）的私人生活和公开讲话发现： They adopt one pose in public, but when it comes to what matters most in their own lives their property, their privacy, and their children--they jettison their liberal principles and adopt conservative ones.
The Olympic Games provides a valuable opportunity for an exchange between cultures and the IOC has taken on the responsibility of highlighting this within the Olympic Movement. The Commission for Culture and Olympic Education was created in 2000 to advise the IOC on the best policies and programmes to help the promotion of culture and Olympic education. Working with the Commission, the IOC developed an Olympic education policy that seeks to provide greater resources to help promote culture and education through sport at national, regional and international level, and particularly at the Olympic Games. Activities related to the education of youth through sport play a key role within the programme. The IOC also worked closely with the London Organising Committee of the Olympic and Paralympic Games (LOCOG) to establish the London 2012 International Education Programme. The team behind the programme provides schools around the world with resources that encourage young people to learn about the London 2012 Games and the Olympic Movement’s values. Later this year, the 8th edition of the IOC World Conference on Sport, Education and Culture will take place in Amsterdam, in partnership with the United Nations Educational, Scientific and Cultural Organization (UNESCO) and in collaboration with the National Olympic Committee of the Netherlands (NOC*NSF). Delegates from 177 different nations will convene to learn more about the importance of sport as a mediator for social and economic development within the context of a sporting, educational and cultural framework. Another of the IOC’s initiatives is the Olympic Values Education Programme (OVEP), which aims to maintain young people’s interest in sport and encourage them to practise sport, while also promoting the Olympic values. For IOC President Jacques Rogge, sport helps to facilitate key social benefits: “Sport is a powerful tool for reaching out to today’s young people on all continents and for educating them early on about healthy and responsible behaviour.” In 2010, the first summer Youth Olympic Games (YOG) took place in Singapore, followed by a winter edition in Innsbruck in 2012. The Games are designed to inspire young people around the world to participate in sport, and to live by the Olympic values. They not only provide an opportunity to participate in sporting competitions at the highest level, they also act as a catalyst for sporting, educational and cultural initiatives thanks to the Cultural Educational Programme (CEP) that runs throughout the Games. The programme introduces young athletes to Olympism and the Olympic values and raises awareness of important issues such as the benefits of a healthy lifestyle and global challenges. 原文见 http://www.olympic.org/news/education-is-key-to-ioc-principles/171840
上次写了一点 Surface dipole moment and work function change , 下面再谈一点相关的问题，即表面计算中的偶极修正. 在第一原理计算建模中，表面通常是由一个若干层的slab加上一定厚度的真空层来模拟。真空层的存在是周期性边界条件决定的。周期性边界条件决意味着slab的images 会周期性的重复，而真空层的作用就是保证这一artificial的重复不会对真正模拟的表面产生影响。当真空层厚度大于10Å时，总能一般已经收敛。不过work function远没有收敛，原则上也不会收敛(周期性边界条件决定的)。很多计算中work function是很重要的，为了得到"收敛"的work function, 就要使用偶极修正. 原理是在真空层中央引入一个artificail偶极子（与表面偶极大小相同，符号相反) 来抵消表面偶极引起的势能梯度. 原则上，知道表面偶极的大小后，可以不做偶极修正就可以得到表面两侧work function 的大小, 即: phi_m_axis = -d_phi/2 - efermi # 负轴侧表面work function phi_p_axis = d_phi/2 - efermi # 正轴侧表面work function efermi 为fermi level d_phi的计算见 Surface dipole moment and work function change
Lutz Bornmann在Scientometrics (2011) 86:173–177发表了一篇题为“Mimicry in science?”的文章。这篇文章涉及了一些科研评价、科研人员的行为等有关话题。正好这几天在与几位前辈探讨中涉及到了这方面的内容。下面对这篇文章的主要内容做了一些翻译，与大家分享，从中也许可以获得一些感兴趣的研究主题。 Abstract： Since bibliometric indicators have obtained a general acceptance in science policy and attained applied relevance in research evaluation, feedback effects on scientists’ behaviour resulting from the use of these indicators for science funding decisions have been reported. These adaptation strategies could be called mimicry in science. Scientists apply strategies that should enable them to comply to bibliometric accountability and to secure funds to their own research. Keywords： Research evaluation Mimicry Scientific progress Bibliometric data are being used by leading and fast-growing countries in science for research evaluation purposes. In UK the allocation of public funds to the universities will be mainly carried out according to these data. “The Government has a firm presumption that after the 2008 RAE the system for assessing research quality and allocating “quality-related” (QR) research funding to universities from the Department for Education and Skills will be mainly metrics-based (UK Office of Science and Technology 2006)“. Due to this development “the death of peer review” in the allocation of research funds is being discussed (Gilbert 2006). The reason for the popularity of bibliometrics compared to peer review is seen in lower costs and criticism of the peer review system (Weingart 2005). In an ever more complex science system, bibliometric analysis should allow for evaluation of mass-data no longer understandable to the single reviewer (Butler 2004). 科研人员行为的耦合 Back coupling on scientists’behaviour Since science funding has become more and more determined by principles of ‘publish or perish,’ the following changes of publication behaviour have been reported in the literature (see here Lawrence 2003; Research Evaluation and Policy Project 2005): (1) To increase probability of acceptance of their papers by a journal, scientists tend to do research in accordance with the mainstream in their fields and avoid unusual research (e.g. risky, interdisciplinary or long-term); (2) To be able to come to publishable results more quickly, scientists pursue short-term rather than longterm research; (3) Scientists attempt to provide their paper to low-quality journals as long as these journals are indexed by literature data bases used for bibliometric analyses in research evaluation; (4) To boost the number of publications, scientists slice their findings as thin as salami and submit these to different journals even though findings could be presented in a single paper. 当科学基金越来越被"出版或出局"这个规则所决定时，科研人员的发文行为就会出现下面一些特点： （1）为了增加自己论文被一个期刊录用，科研人员的研究会更加遵循所在领域的主流研究，而放弃一些冒险、跨学科、长期研究等“不太规矩”的研究。 （2）为了能够尽快发表其研究成果，科研人员更趋向于一些短期研究。 （3）科学家会尝试在一些质量相对较低，但是又科研评价中被确定的期刊上发表论文。 （4）有的时候，一篇文章本来就可以把一项研究成果一次性发表，但科研人员会象切香肠一样，把一项研究内容有意识地拆开，然后在不同期刊上发表。 这种现象在生物学上叫“仿生”（mimicry，Patent 1978） Fraser and Martin (2009)研究发现，在科学论文中经常会出现关键的、决定性的、重要的（e.g. pivotal, crucial, and essential）等词汇。这个发现是科研人员想通过这些词汇的运用来增加其论文被录用的可能性。Merton (1938)认为，在这种极端的“仿生”会导致一个混乱的状态。Merton (1938)研究了社会结构如何影响对特定的人群，这种影响是鼓励这些人群去遵守规则，还是不守规范。如果“赢得比赛”超过了“在一定规则下赢得比赛”，那么破坏规则的现象就会发生(Martinson et al. 2006)。如果科研人员去迎合基于评价指标的目标，科学不端行为的现象就会出现。很多情况下，发文的压力会导致学术不端行为的出现。中国一些大学的高质量成果与奖金、房子、津贴等挂钩的同时，也在面临着不少学术失范行为（Qiu 2010）。 Increase in productivity as an effect of national research evaluation systems 发文量增加对国家科研评价系统的影响 在过去一些年，除英国外，象澳大利亚、芬兰等国家利用评价系统来分配科研资金的做法被不断完善 (see an overview in Macilwain 2010; Schneider 2009)。一些调杳表明，这些评价系统对科研人员的行为产生了一定的影响。在澳大利亚(Butler 2003, 2004)，自从“发文等于基金”（formula based funding）的制度实施之后，科研人员每年的发文量有了很大的提升 (如发文的与基金分配的关系），虽然这些文章被发表在WOS收录的期刊上，但多数是在低影响因子的期刊上。 Glaser and Laudel (2007)的5位访谈者表示，他们改变了他们的发文策略：发更多的论文、独立发表论文、在高影响力的期刊上发文。而且被采访对象更倾向于一些应用性和热点研究主题的论文。在西班牙，科研人员根据the National Commission for the Evaluation of Research Activity (CNEAI, Madrid)的规定在高水平的期刊发表其成果。一项对科研政策影响的测度表明：首先，这种政策导致了西班牙科研人员发文习惯的变化，其次，科研人员在ISI收录的西班牙期刊上发文的数据在增加；第三，西班牙文献计量数据库的source items趋于稳定(Jimenez-Contreras et al. 2002)。同样的影响也其它的研究中被发现（Rey et al. 1998）。UK RAE Moed (2008) 发现，三种明显的文献计量模式可以来解释科研人员对RAE标准的适应。RAE1992强调发文总数时，英国科研人员的发文量就出现一个确定的增长。当RAE1996注重由数量向质量转变时，英国科研人员的发文和被引次数都有了提高。在1997–2000年之间，机构增加了其科研人员的数量，并鼓励研究人员之间紧密合作，即使论文并不是真正合作的产物。 Possibilities of increasing citation impact 提高引用影响的可能性 与发文量相比，被引次数对科研人员似乎是不敏感的。但是Bornmann and Daniel (2007)研究结论正好相反。......只有少数研究人员能够看较多的所在领域的文献，因此，写越多的论文，其被引用的可能性越大。 Do behavioural changes contribute to scientific advancements in science? 科研人员的行为变化对科学发展是否有益？ 世界各中政府要求科研人员有更多的产出才能获得持续的支持 (Mervis 2007)。评价体系的引入希望能够提升科研人员产出的数量与质量。这种系统导致科研人员行为的变化正是政府想要的结果。数量是指在同行评审期刊上发表的论文数量，研究的影响和重要性是通过被引次数来衡量的(National Science Board 2010)。一些研究表明，这种适应过程在实际中被观察到。不管这种科学中的“仿生现象”如何解释，没有对科研起步产生正面影响而被科研人员人为操纵是错误的。Evidence Ltd（2007）：一个与基金分配相关的指标，它一开始就失去了最初扮演某个角色的信息内容。有了一所可操纵的房子，就可能会导致在些意外行为只是去获得部分研究过程和它的利益。 这种行为的适应性也可以对科技进行有正面的影响。一方面，科研人员在SCI收录的低影响因子上发文是负面的，另一方面，这些期刊能够作为来源刊，它们也是要达到一定标准的。低影响因子期刊比高影响因子期刊的质量相对较差，但还是要好于那些没有被作为来源刊的期刊。一方面，好多研究人员都倾向于主流的研究是有问题的，但这些主流是一个领域最重要的研究内容。追求短期影响就真的比长期的研究会影响科学的进步吗（(Laloe¨ and Mosseri 2009)?）在大科学时代，短期影响会不会影响规则？要回答这些类似的“科学仿生问题“，要深入研究评价系统、发文行为和引用行为的适应性和科学知识生产需要之间的联系是非常必要的。 （In times of big science (de Solla Price 1965), isn’t short-term impact the rule? To be able to answer these and similar questions concerning mimicry in science satisfyingly, the results of in-depth analysis on the relationship between an evaluation-based research system, adaptation of the publication and citation behaviour and scientific knowledge production are needed.） 原文可以从： http://www.lutz-bornmann.de/icons/Mimicry.pdf 下载 一点感受：一个评价系统，一个评价指标，总有其局限。系统、指标并无严格的好坏之分，更多的应该是如何合理去应用。应用得当，扬长避短，就有可能事半功倍。
http://www.mdbbs.org/thread-5696-1-1.html 简单的第一性原理介绍 什么是第一性原理计算(What are first principles calculations?) 1。What are first principles calculations? A material is simply a collection of atoms that are bound by chemical reactions. Chemical reactions, in turn, are simply interactions between electrons . These interactions are described by the laws of quantum physics. This means that all material properties (chemical, mechanical, electrical, magnetic, optical, thermal,…) can, in principle, be predicted from nothing more than the atomic number and mass of the atomic species involved , with the aid of quantum physics. This is precisely what first principles calculations attempt to do. One of the joys of first principles calculations is that a few atomic numbers make abstract quantum concepts come to life in the form of quantitatively accurate, experimentally verifiable predictions- for quantities ranging from the Young modulus of diamond to the absorption spectra of conjugated polymers . 2。How do we do first principles calculations? Solving the Schrouml;dinger equation by brute mathematical force is extremely demanding computationally and not practical for all but tiny systems. Instead, we use a combination of two physical approximations : 1. We use density functional theory (DFT) , for which Prof. Walter Kohn was awarded the 1998 Nobel prize in chemistry . DFT maps the original many-electron problem into an equivalent single-electron problem. It does so by lumping all the many-body quantum phenomena (such as Pauli’s exclusion principle and electron correlation) into a single additive “exchange-correlation” potential , which is a functional of the charge density alone . In principle, this mapping is exact. In practice, the exact functional is unknown and people use approximate forms for the functional , usually (but not always) derived from properties of a uniform electron gas . 2. We use first principles pseudopotential theory . The periodic table tells us that chemical reactivity is governed by valence electrons, with core electrons being chemically inert . Pseudopotentials make use of this basic fact by replacing the inert core electrons with an effective potential . This reduces, sometimes drastically, the number of electrons we need to solve for. Even more importantly, this results in much smoother wave functions for the remaining valence electrons , making the problem much easier to solve numerically. For the calculation of excited state properties (notably optical ones), we have to move beyond DFT , which is a ground state theory . Our favorite tool is time-dependent DFT –an extension of the original method. Doesn’t the use of physical approximations mean that we’re not really doing first principles work? No! Our approximations are systematic. All “hidden parameters” within them are determined objectively from theoretical results for properties of the electron gas (DFT) or the isolated atom (pseudopotentials), and not by fitting experiments. 百度的解释： 第一性原理通常是跟计算联系在一起的，是指在进行计算的时候除了告诉 程序 你所使用的 原子 和他们的位置外，没有其他的实验的，经验的或者半经验的参量，且具有很好的移植性。作为评价事物的依据，第一性原理和经验 参数 是两个极端。第一性原理是某些硬性规定或推演得出的结论，而经验参数则是通过大量实例得出的规律性的数据，这些数据可以来自第一性原理(称为理论统计数据)，也可以来自实验(称为实验统计数据)。 但是就某个特定的问题，第一性原理和经验参数没有明显的界限，必须特别界定。如果某些原理或数据来源于第一性原理，但推演过程中加入了一些 假设 (这些假设当然是很有说服力的)，那么这些原理或数据就称为“半经验的”。 其他解释： 第一性原理，英文First Principle，是一个计算 物理 或计算 化学 专业名词，广义的第一性原理计算指的是一切基于量子力学原理的计算。 我们知道物质由 分子 组成，分子由原子组成，原子由原子核和电子组成。量子力学计算就是根据原子核和电子的 相互作用 原理去计算分子 结构 和分子 能量 （或离子），然后就能计算物质的各种性质。 从 头算（ab initio） 是狭义的第一性原理计算 ，它是指 不使用经验参数，只用电子质量，光速，质子中子质量等少数实验数据去做量子计算。但是这个计算很慢，所以就加入一些 经验参数 ，可以大大加快计算速度，当然也会不可避免的牺牲计算 结果 精度 。 那为什么使用“第一性原理”这个字眼呢？据说这是来源于“第一推动力”这个宗教词汇。第一推动力是牛顿创立的，因为牛顿第一定律说明了物质在不受外力的作用下保持静止或匀速直线运动。如果宇宙诞生之初万事万物应该是静止的，后来却都在运动，是怎么动起来的呢？牛顿相信这是由于上帝推了一把，并且牛顿晚年致力于神学研究。现代科学认为宇宙起源于大爆炸，那么大爆炸也是有原因的吧。所有这些说不清的东西，都归结为宇宙“第一推动力”问题。 科学不相信上帝，我们不清楚“第一推动力”问题只是因为我们科学知识不完善。第一推动一定由某种原理决定。这个可以成为“第一原理”。爱因斯坦晚年致力与“大统一场理论”研究，也是希望找到统概一切物理定律的“第一原理”，可惜，这是当时科学水平所不能及的。现在也远没有答案。 但是为什么称量子力学计算为 第一性原理计算 ？大概是因为 这种计算能够从根本上计算出来分子结构和物质的性质，这样的理论很接近于反映宇宙本质的原理，就称为第一原理了 。 广义的第一原理包括两大类 ，以 Hartree-Fork自洽场计算为基础的ab initio从头算 ，和 密度泛函理论（DFT）计算 。也有人主张，ab initio专指从头算，而第一性原理和所谓量子化学计算特指密度泛函理论计算。
标签: Principles
