高中学生对曲线运动类题目的分类方法研究

题目分类方法研究是物理教育研究领域中的一项重要内容,可以揭示学生对于物理概念的建立过程.本文运用物理问题表征分类的研究方法,通过对高中3个年级的学生进行测试,总结了高中学生对曲线运动类题目的分类特点,分析了不同年级学生的分类差异,并研究了图示对于学生分类方式的影响.结果显示,高一学生中有较高比例会按照所求解的未知量等表面特征对问题进行分类,且容易受到示意图的干扰;高三学生则较多按照题目涉及的核心概念与原理对题目进行分类,且在分类时能够较好地排除题目中的干扰因素.     

浮区区熔生长的单晶光纤形状稳定问题

本文用晶体区熔生长理论对激光加热基座法生长的单晶光纤形状稳定问题作了研究.说明了稳定生长的熔区长度与晶纤直径、源棒直径的关系.讨论了影响晶纤直径波动的干扰因素.指出了干扰因素中激光功率的稳定和源棒直径的均匀是主要的.理论推出的结论得到实验证实.     

全息照相实验中各种振动对系统稳定性影响的研究

通过设计一个简单的马赫-曾德干涉光路,得到合适的干涉条纹。通过演示实验者倚靠实验平台、在光路附近说话、在平台附近走动以及楼层振动等干扰条件,利用光强传感器实时监控条纹的变化,表征了上述振动干扰对条纹漂移的影响。上述结果对于学生直观理解全息照相过程条纹漂移的干扰因素将有一定帮助,同时有利于学生在实验过程中避免上述问题,提高全息照相实验成功率。     

对干扰学生学习物理心理的研究

初中学生普遍感到物理有趣,但很多学生感觉不好学,原因是多方面的,但心理因素是主要的.本文主要从生活经验,思维定势,情境,情绪,隐形条件,逆反心理等方面来分析干扰学生学习物理的主要的心理因素.     

信息题的结构特征与建模途径探讨

近年来,高考物理试卷中出现了一种新题型--信息给予题,简称信息题.这类考题立意高、选材活,具有鲜明的时代气息,对学生的能力与素质,尤其是阅读理解能力、分析推理能力、理论联系实际的能力、心理适应和承受能力均提出了较高的要求.深刻分析这类考题,虽然题设情境充满了时代气息,题目的载体却离不开基本的物理模型,解题的成败往往取决于学生是否能透过纷繁的背景材料,排除干扰因素,捕捉有用信息,构建物理模型.     

调强连续波激光测距系统中的电子交调干扰

在调强连续波激光测距系统中,调制激光器的高频电流源产生的泄漏干扰是影响测距精度的主要因素。本文对此泄漏干扰进行了系统研究,分析了干扰产生的原因,干扰与测距精度的关系,给出了干扰误差的计算公式以及补偿方法。     

壁内测温热偶对瞬态温度场干扰的模拟分析

用19×25个结点的电阻——电容二维网络模拟插入了热电偶的半无限大物体.计算了热偶孔对温度场的干扰,得出了孔区平均导热率、比热以及孔底形状、孔端接触面积等因素对干扰的影响.     

基于水声信道传播时延排序的分层空时信号检测

基于分层空时编码的多输入多输出技术是一种极具潜力的高速水声通信技术, 但要实现这种潜力需要复杂的空时信号处理方法, 以抵消来自水声信道的多径干扰和异步到达干扰, 以及叠加在接收端的各层信号之间的干扰. 对低复杂度的空时信号处理方案进行了研究, 提出了一种基于子信道传播时延排序的有序连续干扰抵消信号检测算法, 利用子信道间的传播时延差, 实现可使差错概率最小的最佳检测排序; 给出了利用信道估计, 以极低的计算量确定排序的方法, 从而可以大幅降低信号检测的计算复杂度. 采用低复杂度的单载波频域均衡来抵消水声信道中的码间干扰和异步到达干扰. 仿真结果表明, 基于时延排序的信号处理算法可以获得检测性能的改善, 而且性能增益在高数据率时更加显著. 研究结果表明, 采用有效的信号处理方法可使水声信道中造成信号检测干扰的传播时延成为改善系统性能的有利因素.     

高中物理习题错解常见的思维障碍诊断

物理习题教学是帮助学生深化理解基础知识和认知过程,发展认知结构,熟练运用和巩固知识及培养技能的过程,又是帮助学生树立物理思维方法,进行思维训练的过程.但在实际习题教学中,学生常会出现思维上的障碍.本文从研究学生解题心理人手,分析学生在解答物理习题时的几种思维障碍,以便教师能准确地掌握学生的解题心理,采取相应的教学措施,尽量避免学生解题时不当的心理干扰,以提高教学质量.     

光声光谱多组分气体分析仪的交叉干扰特性研究

设计了一套基于红外热辐射光源的光声光谱多组分气体分析仪.通过分析多组分气体间交叉干扰的主要因素以及特征气体的红外吸收谱线,确定了中红外带通滤光片的参数.利用标准气体对设计的光声光谱仪进行标定,研究了待测气体之间交叉干扰的定量关系,并利用湿度发生器对装置受到水气干扰情况进行分析.实验结果表明,C2H2对CH4、CH4对C...     

关于"太阳在银河系中所受引力与到银心距离r的关系"的讨论

讨论了银道面内的引力场强分布和太阳在银河系中所受引力与到银心距离r的关系，指出引力场强g并不是与r的平方成反比，这是由于银河系的大小和形状不能忽略造成的．强调了万有引力定律的适用条件．     

On the predictability of the positions of the convergence zones in the ocean

The disagreement between the experimental and calculated positions of the first convergence zone are known from many publications. The most probable cause for such a disagreement, namely, the incorrect specification of the input data for the calculations, is considered. The lack of simultaneity between the hydrological surveys of the region and the acoustic experiments is emphasized. The experimental data obtained by the author in five ocean regions are presented. These data characterize the diurnal variability of the distance from the source to the nearest boundary of the convergence zone. The relations proposed by different researchers for calculating the sound speed from the temperature, salinity, and hydrostatic pressure are analyzed. It is shown that these relations lead to a substantial difference in the estimated depth dependence of the hydrostatic gradient of the sound speed. The position of the first convergence zone is calculated for the propagation conditions determined by vertical temperature and salinity profiles with the subsequent recalculation of these profiles into sound speed profiles by using eight different formulas known from the literature. It is shown that different formulas lead to different values of the distance to the first zone; this difference is substantially greater than that between the calculations and experiment. The necessity of improving the recalculation relations in view of the experimental data on sound propagation in natural oceanic waveguides, including the data on the actual positions of the convergence zones, is emphasized.     

On the calculation of the bremsstrahlung in the region of the plasma frequency

On the basis of the classical theory of radiation produced in incomplete Coulomb interaction, a formula is derived for the coefficient of the bremsstrahlung of fully ionized plasma. In the region of rectilinear approximation a comparison is made with the results of the quantum formula derived from the Born approximation. Furthermore, the influence of dispersion upon the emission coefficient is taken into account; some relations for the region of dispersion are given.     

Dependence of the Intensity of the Spectral Lines and the Composition of the Sample and the Plasma Parameters of the Unipolar Arc

The investigation was made of the dependence of the intensity of Tl, Ga, Mo, Mg, Mn, Sn, Bi, Ni, Zn, Pt and Au spectral lines and the plasma parameters (temperature T, electron concentration n_e, degree of 6 ionnization α) from concentration of lithium additive.     

Extracting the wavefunction of the LSP at the LHC

We consider associated production of squarks and gluinos with the lightest supersymmetric particle (LSP), or states nearly degenerate in mass with it. Though sub-dominant to pair production of color SU(3)-charged superpartners, these processes are directly sensitive to the wavefunction composition of the lightest neutralinos. Exploiting event-shape variables - including some introduced here for the first time - we are able to identify the composition of the LSP by selecting events involving a single high-pT jet recoiling against missing transverse energy. We illustrate the proposed technique on a set of benchmark cases and propose methods for applying these results in more realistic experimental environments.     

Set the controls for the heart of the Sun

In this paper we describe experiments conducted with high-power lasers that are attempting to replicate, for a very short time and in miniature, conditions found in the Sun. Experiments to date have reached conditions in the outer part of the Sun. To reach the Sun's centre requires compression of material to very much greater than solid density and heating to over ten million degrees. To achieve this, a new class of experiments and a new generation of high-power lasers are required.     

On the Question of the Source of the Apokamp

Technical Physics - The object of this work is the apokamp—a new type of plasma jet, which is formed from a bright offshoot emerging at the bending point of a channel of a high-voltage...