物理黑箱习题的思维训练功能

物理黑箱习题的思维训练功能申探禄（广东湛江一中５２４０３８）黑箱习题是近几年来颇为流行的一种新型物理习题，和其他类型的习题相比较，黑箱习题具有以下十分显著的思维训练功能。１．逆向思维训练所谓“黑箱”（亦称黑盒，黑匣等），是指内部元件或结构不能直接看到...     

例谈解答物理习题的一般步骤

许多同学做了大量的物理习题，解题能力仍然没有多大提高，纠其原因，就是没有形成一般的解题方法．笔者通过对具体习题的求解过程，例谈解答物理习题的一般步骤．     

大学物理习题层次化设计与分析

本文讨论大学物理习题改革问题，举例介绍了习题的层次化设计．探讨层次化习题在培养学生运用不同层次的物理模型和数学工具，提高分析、解决实际问题能力，激发学习能动性方面的积极作用。     

整合习题资源实施有效复习教学

高三的习题教学是巩固学生的基本知识和技能，进一步领会物理的思想方法，提升解题能力和技巧的重要环节．如按照教材的编制顺序，按部就班进行教学，学生对概念和规律仍会按章节割裂来理解，知识是离散的、零碎的，这样的习题教学既费时又费力，效果也不理想．整合习题，本质上是提高物理知识的综合运用能力．通过对形式各异习题的重组和辨析，充分挖掘习题资源，这样不仅可在有限的时间内给学生搭建好较为完整的知识网络，渗透较为全面的物理方法，从而提高解题素养，而且还能向学生提供解题的框架，给学生解题进行正确定向，有效迁移，从而提高高三复习的效果．同时，在习题整合的过程中，教师必然会重新审视自己的习题教学，从而提高自身对教材、考纲的把握能力和解题水平，促进自身素质和教学水平的整体提高．     

真的是一回事吗？

电学的习题中，应用电流定义式I=q/t解题时，有这样一道常见的习题：     

检验物理习题答案是巩固知识和培养能力的重要途径

检验物理习题答案是巩固知识和培养能力的重要途径邹艳（山东省德州纺织工业学校２５３００８）物理习题的教学是整个物理教学的重要组成部分．学生通过解答物理习题，可以加深对基础知识的理解，培养运用数学知识解决物理问题的能力，并能激发学生的学习兴趣，调动学生学...     

习题教学如何进行格物致知——以一道音调题目的教学为例

习题教学的目的并不只是让学生学会解题，而是通过让学生分析解决问题，培养其科学探究意识与能力.将中国传统的格物致知精神与习题教学结合，还原题目中的“乐器”,并利用手机phyphox软件指导学生对玻璃水瓶的发声音调进行实验探究.通过这种习题教学方式，使学生格物致知.     

细绳是弹性体还是刚体──小议一道力学习题

细绳是弹性体还是刚体──小议一道力学习题李克坚（广西师大附中桂林５４１００１）在解与细绳有关的力学习题时，绳子是弹性体还是刚性体对解题有着明显的影响，为了弄清这一问题，让我们从一道习题开始。题目：一小球质量为ｍ，用两根悬挂于天花板的等长的细绳ＯＡ、Ｏ...     

教材选题应慎重

物理习题大多是实际问题在忽略了某些次要因素而抽象出的理想化模型，它是学生在学习了物理理论知识后的初步实践，通过练习可以达到巩固理论知识、消化课堂教学的目的，因此在习题的选择上应谨慎，虽说是理想化的问题，也不应远离实际，而是要贴近我们的生活，这样学生做题就比较有兴趣，通过习题也能学到一些生活知识。     

发掘与开拓新颖物理习题的教学设计

尝试从实际现象中发现、发掘和开拓新颖的习题，以改变习题脱离实际、僵化呆板的现状，以助于改变学生只会做题不会思考和解决实际问题的弊端。     

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.