即兴物理实验

论述了即兴物理实验的优越性，并列举了几个即兴物理实验。     

对实验课教学过程的思考

职业技术教育的特点是以培养学生动手能力为中心,以培养学生技能为目标,因此职业学校必须重视实验教学。通过实践,使学生认识、理解、验证基本概念和定律;训练学生基本操作技术;通过课程设计,生产经营实践,培养学生的职业能力。实验课的教学包括选题与准备、讲授与示范、操作与指导、评议与总结四个阶段。本文就这四个阶段的教学谈谈自己的一点思考心得。     

对"Aspect实验与量子力学解释"一文的折磨

简述了Ｂｏｈｍ思想实验和Ｂｅｌｌ不等式中存在的问题，指出Ａｓｐｅｃｔ实验同Ｂｏｈｒ与Ｅｉｎｓｔｅｉｎ之间的“巨人之争”完全无关。     

文科大学物理实验开设的实践与思考

为文科大学生开设大学物理实验，可培养他们的思维能力、科学观察能力，提高科学素养，拉近其与新科技的距离．本文具体介绍了文科大学物理实验的选题、课程安捧和考核方法．     

牛顿第二定律实验的改进

牛顿第二定律的验证是大学物理实验中的一个基础性实验．它是一个验证性实验，涉及到检验一个物理定律或规律的基本途径和方法．因此对于其实验精度往往有特殊的要求．本文先简要地分析一下现行高校中牛顿第二定律验证实验的方法，然后对其做了一些改进，改进后的实验精简了实验器材，提高了实验精度．     

"最美丽"的十大物理实验给我们的启示

美国纽约大学石溪分校哲学系的教员、布鲁克海文国家实验室的历史学家罗伯特·克瑞丝最近在物理学家中作了一次调查,要求他们提名历史上最美丽的实验,2002年9月份出版的《物理学世界》刊登了排名前10位的最美丽的物理实验.     

高考物理实验命题引领实验教学

高考物理实验题是近几年一直热门的,把握实验题的考查方向是高考物理得高分的利器.本文主要是从课堂实验教学中所设计的几种实验来阐述课堂实验教学对高考物理实验题的影响.     

"细致"与"创新"的整合--物理实验复习的新视角

近几年来物理实验内容在高考中的权重基本保持在13％～15％，实验内容涉及演示实验和设计实验等，试题的形式多样，面貌不断创新，越来越引人瞩目。从增强学生的实验意识，培养实验思维，提高实验能力出发，物理实验的复习策略必须注重“细致性”和“创新性”两个方面的整合。     

试探探索性物理实验课题的设计

1引言 探索性物理实验是这样一类实验，它是由教师给出实验课题，提供实验器材，提出实验要求，然后让学生自己拟定实验方案，制定实验步骤，主动收集有关信息，通过实验的观测和分析以及与他人的合作和交流去探索研究，从而发现“新”的物理现象，并通过提出猜想或假说，设计验证实验和按设计要求进行操作性实验，总结出他们原来并不知道的规律性的结论．整个探索过程包括提出问题、猜想与假设、制定计划与设计实验、进行实验与收集证据、分析与论证、评估、交流与合作几个基本要素．     

气垫导轨实验的拓展

针对传统的气垫导轨实验起点低，过于简单这一缺憾，提出了一种新的实验原理及实验方法，使其内容得以拓展。     

Guided-Wave Two-Dimensional Acousto-Optic Scanner Using Proton-Exchanged Lithium Niobate Waveguide

Two-dimensional scanning of a 0.6328 mum guided-light beam has been realized using noncolinear acousto-optic (AO) coplanar Bragg diffraction together with colinear AO guided-mode to substrate radiation-mode conversion in a Z-cut Xpropagation LiNbO3 proton-exchanged (PE) waveguide. The two surface acoustic (SAW) waves utilized are at the center frequencies of 500 and 200 MHz, propagating in the Y and X axes, respectively. Two-dimensional scanning of approximately 720 resolvable light beam spots, namely, 18 40 (horizontal vertical) scanning, has been demonstrated using a light beam of 1.0 mm aperture. The total number of resolvable beam spots can be greatly increased from 720 by simply utilizing SAW transducers of larger bandwidth and a light beam of greater aperture. It should also be possible to significantly increase the diffraction efficiency from 3 % by optimizing the parameters of the PE waveguide and the SAWs.     

Femtosecond Transform-Limited Pulse Generation by Compensating for the Linear Chirp of SPM Spectra in Dispersion Shifted Fibers

A simple technique of pulse compression, based on the linear chirp compensation of self-phase modulation (SPM) spectra in dispersion shifted fibers, is demonstrated. The optimization procedure is carried out, for a short span of a single-mode fiber, using a parabolic law, which describes the behavior of the squared output pulse width versus the pump peak power in the case of Gaussian pulses. The experimental results give a minimum pulse duration of 233 fs, which is in good agreement with the model. Shorter and coherent pulses, down to 90 fs, have been obtained by inserting an interference filter at the optical output.     

Effect ofγ-radiation on the spectral luminescence characteristics of impure cadmium tungstate crystals

Results of a study of the effect of γ-radiation on the spectral luminescence properties of cadmium tungstate crystals doped with silver, bismuth, and molybdenum cations are presented. Spectral characteristics of the nondnnnoped crystals are briefly described. Absorption and photo and X-ray luminescence spectra of the crystals taken before and after exposure to γ-radiation (5.5·10⁴ Gy) are compared. It is found that the spectral characteristics of the crystals doped with silver, bismuth, and molybdenum cations do not change markedly after the exposure. The relation between the type of impurity-induced defects, individual characteristics of the impurity cations, and the character of the effect of γ-radiation on the spectral luminescence properties of impure crystals is analyzed (preliminarily). Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 64, No. 1, pp. 55–60, January–February, 1997.     

Theoretical analysis and simulation of conjugate heights for dual-conjugate AO system in lidar

A multi-conjugate adaptive optics （MCAO） can offer a possibility of widening field of view （FOV） characterized by the isoplanatic angle, and the choose of conjugate height becomes a basic problem for MCAO, which influences the size of iosplanatic angle. Considering the application of lidar, the isoplanatic angle＇s expressions of two deformable mirrors （DMs） MCAO for uplink and downlink are deduced. The effects of conjugate heights for dual-conjugate AO are thoughtfully discussed, and the isoplanatic angles are further analyzed. The results show that the isopanatic angle varies with the conjugate height and reaches the maximum as the conjugate height is at the optimal altitude. Moreover, the optimal conjugate height changes with the propagation distance.     

Quick single-photon detector with many avalanche photo diodes working on the time division

Due to the limit of response speed of the present single-photon detector, the code rate is still too low to come into practical use for the present quantum key distribution (QKD) system.A new idea is put up to design a quick single-photon detector.This quick single-photon detector is composed of a multi-port optic-fiber splitter and many avalanche photo diodes (APDs).Au of the ports with APDs work on the time division and cooperate with a logic discriminating and deciding unit driven by the clock signal.The operation frequency lies on the number N of ports, and can reach N times of the conventional single-photon detector.The single-photon prompt detection can come true for high repetition-rate pulses.The applying of this detector will largely raise the code rate of the QKD, and boost the commercial use.     

Sorting of bending magnets for the SSRF booster

The Shanghai Synchrotron Radiation Facility(SSRF)booster ring,a full energy injector for the storage ring,is deigned to accelerate the electron beam energy from 150MeV to 3.5GeV that demands high extraction efficiency at the extraction energy with low beam loss rate when electrons are ramping.Closed orbit distortion(COD)caused by bending magnet field uniformity errors which affects the machine performance harmfully could be effectively reduced by bending magnet location sorting.Considering the affections of random errors in measurement,both ideal sorting and realistic sorting are studied based on measured bending magnet field uniformity errors and one reasonable combination of bending magnets which can reduce the horizontal COD by a factor of 5is given as the final installation sequence of the booster bending magnets in this paper.     

Improvement of four-wave mixing-based wavelength conversion efficiency in dispersion shifted fiber by 40-GHz clock pumping

40-GHz clock modulated signal as a pump to improve the efficiency of four-wave mixing (FWM)-based wavelength conversion in a 26.5-km dispersion shifted fiber (DSF) is investigated. The experimental results demonstrate that the conjugated FWM component has higher intensity with the clock pumping than that with the continuous-wave (CW) light pumping. The improvement of FWM-based wavelength conversion efficiency is negligible when the pump power is less than Brillouin threshold. But when the pump power is greater than Brillouin threshold, the improvement becomes significant and increases with the increment of pump power. The improvement can increase up to 9 dB if pump power reaches 17 dBm.     

Characterization of PolyA and PolyC mismatches by Raman spectroscopy

A.C mismatches are studied by Raman spectral characterization of PolyA, PolyC, and their equimolar complex in solution of 0.14 mol/L Na ,pH7.0.Experimental results show that A·C mismatches occur to be A/B (mainly A) conformers, and unlike Watson-Crick base pairing, this kind of mismatches is stabilized by only one hydrogen bond involving cytosine N4H2 and adenine N7.The formation of A·C complex makes the base stacking interactions much stronger, and conformation of the backbone more ordered, which leads to obvious Raman hypochromic effect with some shifts in corresponding bands.