一个集力学和光学实验于一体的综合物理实验

本简述了利用旋转液体测量重力加速度的原理，介绍了测量重力加速度的方法，给出旋转液体凹表面的焦距与旋转周期的关系以及利用其液面成像的方法。     

旋转液体实验装置的设计

对如何利用旋转液体这一有趣现象进行物理实验作了探索，设计出一套用于进行旋转液体实验的仪器，并介绍了该仪器的设计思路及特点。     

创新和改进实验仪器优化物理教学倡--用旋转的液体探究安培力实验

本文就如何创新和改进实验仪器，优化物理教学提出一些观点，针对通常（教科书所述）安培力实验的缺陷，设计了一个用旋转的液体进行安培力的实验。     

RL-1型旋转液体特性研究实验的改进方法

旋转液体特性研究实验是大学物理实验中典型的综合实验项目之一,本文通过进一步优化现有的RL-1型旋转液体实验仪的设计,解决了两种重力加速度测量方法中存在的旋转液面特征点高度测量不准和反射点位置判断不清的问题,较大地提高了测量精确度,达到了理想的实验效果。     

利用旋转液体特性测量液体折射率

在XY-1型旋转液体实验仪的圆柱形容器底部加装了圆形平面镜,利用旋转液体的几何特性和折射定律,即可测量液体的折射率.     

基于旋转液体特性实验的激光双次反射法测重力加速度

旋转液体特性实验是大学物理实验中典型的综合实验项目,本文利用激光束在旋转液体表面的双次反射时的特性,确定了测量重力加速度的新方法。通过对比实验发现,本设计减少了原有单次激光反射测量重力加速度时的物理量数目,并有效提高了测量结果的精确度。     

旋转液面的光学性质探究及应用

匀速旋转的圆柱形容器带动其中盛放的液体围绕容器中心轴匀速旋转时,液体的表面在离心力与重力的综合作用下会形成一个抛物面.该抛物面的光学焦距与重力加速度和转速有关,从而利用该装置测量了本地的重力加速度,并利用抛物面聚光的性质制成了一个简易的反射式牛顿焦点系统望远镜,还测定了望远镜的横向放大率与转速之间的关系.     

器壁旋转模式下液体平衡状态的分析

基于器壁带动液体旋转稳定后形成的抛物面,推导出器壁斜率为K(K≠0)时的恒等式.得出K→∞时,随着转速增加,液位的变化是无限的,液位的上升高度与下降深度恒相等,旋转抛物体与同底同高圆柱体积关系为定值;当K＞0时,容器为上大下小的圆筒,旋转抛物面导致的液位变化是有限的,存在的极限值为√3+1,当液体旋转角速度超过临界角速...     

基于改进的迈克尔逊干涉仪的液体折射率测量方法研究

液体折射率是重要光学参数之一，液体折射率参数测量在食品生产鉴定、光学加工等领域都具有重要意义。本文基于便携式迈克尔逊干涉仪，在光学减震台上加装旋转微调载物台，综合考虑旋转后容器器壁、待测液体、空气中光程差的改变量，得到液体折射率的计算公式，与阿贝折射仪测量液体折射率的值进行比较，实验测得水、不同浓度的葡萄糖溶液以及不同浓度的氯化钠溶液，平均相对误差分别为1.1%、3.3%、2.0%,实验过程中测量的最大误差为5.9%,为液体折射率测量提供了一种可行方法，实现液体折射率的测量。本文也可作为迈克尔逊干涉仪的拓展实验，对本科生的创新能力培养有重要意义。     

碳酸钙微粒光致旋转的实验和理论研究

理论分析了由于光束轨道角动量和自旋角动量传递以及微粒的特殊形状导致微粒旋转的机理.实验建立了单光束激光光镊装置,不仅可以捕获并移动直径为微米量级的微小粒子,而且利用圆偏振光与微粒之间角动量的传递,实现了对具有双折射特性的碳酸钙微粒的光致旋转.实验中发现微粒的旋转不仅取决于光束的偏振态,还与微粒本身的形状有关,解释了实验中观察到的几种旋转现象.碳酸钙微粒旋转的最高转速达到12转/秒,转速与激光功率成正比.     

The wrong kind of gravity

The KPZ formula [V.G. Knizhnik, A.M. Polyakov, and A.B. Zamolodchikov, Mod. Phys. Lett. A 3 (1988) 819] shows that coupling central charge c≤1 spin models to 2D quantum gravity dresses the conformal weights to get new critical exponents, where the relation between the original and dressed weights depends only on c. At the discrete level the coupling to 2D gravity is effected by putting the spin models on annealed ensembles of Φ³ planar random graphs or their dual triangulations, where the connectivity fluctuates on the same time-scale as the spins.Since the sole determining factor in the dressing is the central charge, one could contemplate putting a spin model on a quenched ensemble of 2D gravity graphs with the “wrong” c value. We might then expect to see the critical exponents appropriate to the c value used in generating the graphs. In such cases the KPZ formula could be interpreted as giving a continuous line of critical exponents which depend on this central charge. We note that rational exponents other than the KPZ values can be generated using this procedure for the Ising, tricritical Ising and 3-state Potts models.     

一类无奇点宇宙模型

按照Penrose-Hawking的奇点定理,在场源物质无旋、无加速且能量密度满足条件ρ+3p≥0的宇宙模型中一定存在奇点.本文研究了场源物质有旋时的无奇点宇宙模型,获得了几种无奇点的宇宙解.     

New Perspectives on the Relativistically Rotating Disk and Non-Time-Orthogonal Reference Frames

The rotating disk problem is analyzed on the premise that proper interpretation of experimental evidence leads to the conclusion that the postulates upon which relativity theory is based, particularly the invariance of the speed of light, are not applicable to rotating frames. Different postulates based on the Sagnac experiment are proposed, and from these postulates a new relativistic theory of rotating frames is developed following steps similar to those initially followed by Einstein for rectilinear motion. The resulting theory agrees with all experiments, resolves problems with the traditional approach to the rotating disk, and exhibits both traditionally relativistic and non-relativistic characteristics. Of particular note, no Lorentz contraction exists on the rotating disk circumference, and the disk surface, contrary to the assertions of Einstein and others, is found to be Riemann flat. The variable speed of light found in the Sagnac experiment is then shown to be characteristic of non-time-orthogonal reference frames, of which the rotating frame is one. In addition, the widely accepted postulate for the equivalence of inertial and non-inertial standard rods with zero relative velocity, used liberally in prior rotating disk analyses, is shown to be invalid for such frames. Further, the new theory stands alone in correctly predicting what was heretofore considered a spurious non-null effect on the order of 10^–13 found by Brillet and Hall in the most accurate Michelson-Morley type test to date. The presentation is simple and pedagogic in order to make it accessible to the non-specialist.     

Effect of Earth's Rotation on the Trajectories of Free-Fall Bodies in Equivalence Principle Experiment

Owing to Earth's rotation a free-fall body would move in an elliptical orbit rather than along a straight line forward to the center of the Earth. In this paper on the basis of the theory for spin-spin coupling between macroscopic rotating bodies we study violation of the equivalence principle from long-distance free-fall experiments by means of a rotating ball and a non-rotating shell. For the free-fall time of 40 s, the difference between the orbits of the two free-fall bodies is of the order of 10-9 cm which could be detected by an SQUID magnetometer because such a magnetometer can be used to measure displacements as small as 10-13 cm.     

一类类光测地线的加速度

类光测地线γ0(λ)与二维类空超曲面φ正交，λ为其仿射参量.假如在类光测地线γ0(λ)上存在一点r(r=γ0(λr))共轭于类空超曲面φ，则对于γ0(λ)上任一点q(q=γ0(λq))满足λq＞λr，一定能把γ0连续变形成一条从φ到q的类时曲线.当产生类时曲线的变分矢量场不是类光测地线上的广义Jacobi场时，这些类时曲线在趋于类光测地线时，它们的固有加速度趋于无穷大. 关键词： 类光测地线 共轭点 变分     

Saddle-point shapes and fission barriers of rotating nuclei

This article reviews the work relating to the development of a rotating liquid drop model together with a chronology of its confrontation with the experimental interpretation of data. It is brought out that the zero temperature rotating finite range model is quite successful in the interpretation of data obtained from heavy ion-induced reactions. Operated by Martin Marietta Energy Systems, Inc., under contract DE-AC05-840R21400 with the U.S. Department of Energy.     

Second kind integral equations for the first kind Dirichlet problem of the biharmonic equation in three dimensions

A Fredholm second kind integral equation (SKIE) formulation is constructed for the Dirichlet problem of the biharmonic equation in three dimensions. A fast numerical algorithm is developed based on the constructed SKIE. Its performance is illustrated via several numerical examples.     

一种可控纳米柱阵列的研制

在一次阳极氧化法制备多孔氧化铝(anodized aluminum oxide,AAO)的基础上,进行了二次、三次、四次氧化制备AAO,并对多次氧化制备多孔AAO的电流变化曲线和模板表面的形貌特点等进行了比较分析.二次、三次、四次氧化制备的AAO纳米孔孔径依次增大、孔间距减小,而模板表面的纳米孔有序性分布没有明显变化.控制一次氧化AAO模板的除膜时间,～10 min即可得到孔径规则、高度有序的AAO膜.最后,利用所制备的不同孔深和孔径的AAO为模板,通过热纳米压印复制技术制备了长度和直径等性质可控的PMMA纳米柱阵列. 关键词： 纳米柱阵列 聚甲基丙烯酸甲酯 多孔氧化铝模板 多次氧化法     

What kind of science is cosmology?

In recent years, by theory and observation cosmology has advanced substantially. Parameters of the concordance or ΛCDM cosmological model are given with unprecedented precision (“precision cosmology”). On the other hand, 95% of the matter content of the universe are of an unknown nature. This awkward situation motivates the present attempt to find cosmology's place among the (exact) natural sciences. Due to its epistemic and methodical particularities, e.g., as a mathematized historical science, cosmology occupies a very special place. After going through some of the highlights of cosmological modeling, the conclusion is reached that knowledge provided by cosmological modeling cannot be as explicative and secure as knowledge gained by laboratory physics.