第12届亚洲物理奥林匹克竞赛实验题介绍与解答

介绍了第12届亚洲物理奥林匹克竞赛所考的"导体在振荡磁场中的悬浮"和"光学‘黑盒子'"2个独立实验的试题及竞赛组织者给出的标准解答.     

第43届国际物理奥林匹克竞赛实验试题简介

第43届亚洲物理奥林匹克竞赛的两道实验试题为"水的磁导率"和"非线性黑盒子".本文较全面地介绍了试题内容,并做了解答,在必要时还结合中国学生的答题情况作出简短评论.     

反射法间接测量物体形状问题的分析--第六届亚洲物理奥林匹克竞赛实验试题之一

介绍了第六届亚洲物理奥林匹克竞赛实验试题中光学黑盒子实验,该题利用光反射方法,判断黑盒子里物体形状,其貌似简单,但要得到好的结果需要有创造性的思维.本文给出了该题实验分析及结果.     

“黑盒子”实验中的电容器

以物理竞赛实验试题为例,讲述了黑盒子实验中电容器元件的判断方法。     

〃黑盒子〃的设计与检测

重庆大学数理学院物理实验中心是全国中学生物理竞赛实验培训基地之一。在该中心开办的培训班中，根据全国中学生物理竞赛实验操作要求，围绕拓展参赛者的思维空间，提高参赛者动手解决实际问题的能力，开设了热学、光学、电学、力学等内容的实验。这些实验内容各具特色，激发了受训同学对物理实验的浓厚兴趣。本文就介绍该中心为竞赛参加者开设的一种电学实验——“黑盒子”实验。     

用示波器检测电磁学黑盒子实验I——物理奥林匹克选拔赛考题之一

介绍了可以用作物理奥林匹克实验培训的电学黑盒子实验的设计思想、实验内容和相应的参考答案 ,并对用该试题在中国物理奥林匹克集训队考试的结果进行了分析 .     

用示波器检测电磁学黑盒子实验Ⅰ--物理奥林匹克选拔赛考题之一

介绍了可以用作物理奥林匹克实验培训的电学黑盒子实验的设计思想、实验内容和相应的参考答案并对用该试题在中国物理奥林匹克集训队考试的结果进行了分析。     

第35届全国中学生物理竞赛决赛实验试题评析

介绍了第35届全国中学生物理竞赛决赛实验试题的实验内容,并给出了试题解析以及竞赛成绩分析.试题1为测量光学玻璃材料的杨氏模量和折射率,可分为3部分:利用洛埃法测量半导体激光器的波长,利用单缝衍射法测定光学玻璃条的杨氏模量,测量厚光学玻璃片的折射率.试题2为测量电学黑盒子,给出其中元件连接的结构和元件性质,利用黑盒子的电路和电容率测量仪等,测量真空电容率和给定介质的相对电容率.实验试题设计性较强,成绩区分度较好.建议学生平时注重基本实验仪器的使用训练,掌握实验技巧,并加强物理基本原理的灵活应用.     

C_(60)中波粒二相性的证据

“任何两个态或更多的态可以叠加成一个新态”,这被称为量子力学的叠加原理.叠加原理看上去显而易见,历史上却是许多量子力学论的起源.据说,谁杀死了猫,将会遭到鬼魂的报复.因此,应设法不让猫知道谁是杀手.为此,薛定谔设计了一套巧妙的装置:把猫关进黑盒子,盒内同时放有一小瓶氰化钾和一个能打破瓶子的α粒子源.将α粒子源的放射剂量设定到这种程序,以至于1小时的放射积累恰好能打破氰化钾小瓶.现在问:在黑盒子被关闭1小时后,猫是死了还是活着?α粒子的放射属于量子力学问题.量子力学只能给出放射剂量随时间累计的可能值,它不能准确地预言…     

第22届亚洲物理奥林匹克竞赛实验试题1的介绍与解答

第22届亚洲物理奥林匹克竞赛实验试题1为磁学黑盒子(Magnetic black box),试题利用智能手机中的磁力计测量磁感应强度随时间的变化,从而研究磁铁在无磁性空心管中的运动及空心管的材料.本文详细介绍了实验试题1的内容,并给出详细解答.     

General scales of community reaction to noise (dissatisfaction and perceived affectedness) are more reliable than scales of annoyance

General measures of reaction to noise, which assess the respondent's perceived affectedness or dissatisfaction, appear to be more valid and internally consistent than more narrow measures, such as specific assessment of noise annoyance. However, the test-retest reliability of general and specific measures has yet to be compared. As a part of the large-scale Sydney Airport Health Study, 97 respondents participated in the same interview twice, several weeks apart. Test-retest reliabilities were found to be significant (p < 0.001) for two general questions and three specific "annoyance" questions. The general measures were significantly more valid for four of the six correlations (with activity disturbance), and more stable than the annoyance scales for five of the six possible test-retest comparisons. Amongst 1,015 respondents at Time 1, the questions regarding general reaction were more internally consistent than the questions regarding annoyance. Taken together, these data indicate that general measures of reaction to noise have superior psychometric properties (validity, internal consistency, and stability) compared with measures of specific reactions such as annoyance.     

Polygonal Billiards with Small Obstacles

The technique of unfolding a polygonal billiard table is used to answer certain questions concerning the illumination problem. The main problem addressed is how many point obstacles would suffice to block any billiard path between two points of the polygon. The answer can then be generalized from point obstacles to small -neighborhoods of points.     

Perception and production boundaries between single and geminate stops in Japanese

The theory of relational acoustic invariance [Pickett, E. R., et al. (1999). Phonetica 56, 135-157] was tested with the Japanese stop quantity distinction in disyllables spoken at various rates. The questions were whether the perceptual boundary between the two phonemic categories of single and geminate stops is invariant across rates, and whether there is a close correspondence between the perception and production boundaries. The durational ratio of stop closure to word (where the "word" was defined as disyllables) was previously found to be an invariant parameter that classified the two categories in production, but the present study found that this ratio varied with different speaking rates in perception. However, regression and discriminant analyses of perception and production data showed that treating stop closure as a function of word duration with an intercept term represented the perception and production boundaries very well. This result indicated that the durational ratio of adjusted stop closure (i.e., closure with an added constant) to the word was invariant and distinguished the two phonemic categories clearly. Taken together, the results support the relational acoustic invariance theory, and help refine the theory with regard to exactly what form 'invariance' can take.     

Interpretation of the curious results of the new quantum formalism of pre- and post-selected systems

The analysis, with the use of two state vectors, of a quantum system, during the time interval between two measurements, leads to some amazing results, which seem to contradict our usual quantum common sense. We explore the questions of compatibility with the conventional quantum theory, uniqueness of pre- and post-selected ensembles, commutativity, simultaneity and reality of strong and weak values in the intermediate time, and the meaning of the weak value. Common criticisms are shown to be unfounded.     

光电信息工程实验教学的思考与改革

面对急剧变化的世界,工程知识本身的有效期变得越来越短,社会对学生各种素质的要求越来越高。如何定位大学工程教育本身的角色?如何在光电工程实验教学中培养社会对学生所提出的各种要求?结合对这些问题的思考,讨论了光电信息工程专业实验教学所面临的挑战,以及为应对这些挑战所进行的教学改革实践。     

首届全国大学生物理实验竞赛试题解答与考试评析(续)

本次全国大学生物理实验竞赛的综合性、研究性实验试题共两题,每道题目包括两部分.目的是综合考察考生对不同物理实验手段的理解掌握水平和综合分析应用能力.各代表队由2人合作在8h内完成两题.两道综合性、研究性试题分别为"用2种方法研究光在不同浓度罗丹明6G溶液中的传播速     

Confinement,deconfinement and freezing in lattice Yang-Mills theories with continuous time

In this paper I analyse lattice Yang-Mills theories with continuous time. After a short discussion of more conceptual questions, such as the existence of a Hamilton operator in the infinite volume limit, I study the phase diagram. The existence of a strong coupling/low temperature confinement phase (which was not proven up to now) is established for arbitrary compact groups, continuous or discrete. For discrete compact groups the deconfinement region decomposes into (at least) two phases, which are distinguished by the behaviour of spatial Wilson loops: a deconfinement phase where spatial Wilson loops still show area law behaviour, and a freezing phase with perimeter law behaviour for spatial Wilson loops. The methods to prove these results rely on cluster expansion methods, combined with renormalisation ideas.     

Axiomatic foundations of quantum physics: Critiques and misunderstandings. Piron's question-proposition system

Some of the most frequent misconceptions about axiomatic quantum physics are discussed with the aim of clarifying their true significance, taking Piron's approach as conceptual framework. In particular, we deal with the following topics: the wrong identification of Piron's questions and Mackey's questions, and some curious alleged empirical consequences; the role of propositions as suitable equivalence classes of questions, their partial order structure, and the paradoxical consequences of the erroneous assignment to questions of some lattice properties involving propositions; the logical and the empirical purport of some negative theorems; the standard Hilbert space model of the theory and the consequent metaphysical disasters related to some identifications, which are peculiar of this model. A controversy between Foulis-Piron-Randall and Hadjisavvas-Thieffine-Mugur-Schächter is analyzed on the basis of the proposed Hilbert space model (in which Piron's questions are realized by Hilbertian effects, i.e., linear bounded operatorsF such that which clarify the different point of views. As an example, we treat the unsharp localization operators inL ₂().     

Demystifying the Light Source Experience

How does a synchrotron work? What is an X-ray laser? How can light sources help solve research problems? How do X-rays interact with matter? What is X-ray Absorption Spectroscopy (XAS)? Transmission X-ray Microscopy (TXM)? Small Angle X-ray Scattering (SAXS)?

These may seem like odd questions for scientists who are already familiar with and rely on access to light source techniques and instrumentation as an essential part of their research. However, if you put yourself in the shoes of a new researcher, you would likely ask these same questions and find the whole topic rather mysterious. Recognizing these difficulties, a workshop was developed to lower the activation barrier for researchers wanting to incorporate light source science into their research. The talks were video recorded and are available online as a resource to the community (https://itunes.apple.com/itunes-u/slac-conferences/id511971711).     

Regularity in Quantum Logic

In 1996, Harding showed that the binarydecompositions of any algebraic, relational, ortopological structure X form an orthomodular poset FactX. Here, we begin an investigation of the structuralproperties of such orthomodular posets of decompositions.We show that a finite set S of binary decompositions inFact X is compatible if and only if all the binarydecompositions in S can be built from a common n-arydecomposition of X. This characterization ofcompatibility is used to show that for any algebraic,relational, or topological structure X, the orthomodularposet Fact X is regular. Special cases of this result include the known facts that theorthomodular posets of splitting subspaces of an innerproduct space are regular, and that the orthomodularposets constructed from the idempotents of a ring are regular. This result also establishes theregularity of the orthomodular posets that Mushtariconstructs from bounded modular lattices, theorthomodular posets one constructs from the subgroups ofa group, and the orthomodular posets oneconstructs from a normed group with operators. Moreover,all these orthomodular posets are regular for the samereason. The characterization of compatibility is also used to show that for any structure X, thefinite Boolean subalgebras of Fact X correspond tofinitary direct product decompositions of the structureX. For algebraic and relational structures X, this result is extended to show that the Booleansubalgebras of Fact X correspond to representations ofthe structure X as the global sections of a sheaf ofstructures over a Boolean space. The above results can be given a physical interpretation as well.Assume that the true or false questions of a quantum mechanical system correspond tobinary direct product decompositions of the state spaceof the system, as is the case with the usual von Neumanninterpretation of quantum mechanics. Suppose S is asubset of . Then a necessary andsufficient condition that all questions in S can beanswered simultaneously is that any two questions in S can be answeredsimultaneously. Thus, regularity in quantum mechanicsfollows from the assumption that questions correspond todecompositions.