对电动向心力定量分析演示仪的改进

针对现有"向心力演示仪"实验的不足,对电动向心力定量分析演示仪进行改进,新仪器保留了电动向心力演示仪的部分元件,改进了转动半径测量和向心力测量装置.通过改变电动机转速、圆周运动半径、金属球质量等参量,该装置可定性演示向心力和定量研究向心力表达式.     

定量探究向心力实验仪

针对以往向心力实验装置存在的若干问题,尝试利用废旧电器、测力传感器、降压稳压模块、处理传感器信号的AD转换模块以及蓝牙信号发送模块等器材制作向心力实验仪.该实验装置既可以进行向心力的探究性实验,也可以进行向心力的验证性实验.     

改进型向心力探究仪

针对传统“ D I S向心力实验器”的不足, 设计了改进型向心力探究仪. 新仪器保留了传统向心力实验器 的部分元件, 改进了转动半径测量和向心力测量装置. 通过改变电动机转速、 圆周半径和砝码质量等参量, 可定量 研究向心力表达式     

自制向心力表达式验证仪

对"圆锥摆粗略验证向心力表达式"实验进行改进,采用减速电动机通过轻杆带动大钢球做匀速圆周运动,形成圆锥摆.改进后的装置运行稳定,操作简单.     

生活化的向心力演示教具

利用小型风扇设计并制作了低成本的向心力演示教具,该装置使得教学用具更加生活化,并具有原理简单、操作简易、定量探究、现象明显等优点.在“探究影响向心力大小因素”的实验中使用,有利于加深学生对向心力的理解.     

用转速表测向心力

本实验装置用转速表来测出物体作圆周运动的转速,得出角速度ω的数值,用测力计测出向心力F的数据,用米尺量出半径R,能定量地找出向心力F、角速度ω、半径R之间的关系:R一定,F∝ω;ω一定,F∝R。从而得出F=mω~2R的公式。实验装置:如下图所示。     

改进DIS装置测量物体转动时所受杆支持力的方向

利用大学物理知识及原理,改进DIS-向心力研究装置,测量在非惯性转动参照系下物体运动所受杆支持力的方向,从而精确判断物体在转动过程中所处状态,如加速（或减速）或匀速等。     

用传感器探究影响向心力大小因素的实验装置研究

实验探究向心力F的大小与质量m、角速度ω和半径r之间的关系是高中物理的一个重要实验。针对传统实验装置存在的不足,新设计的实验装置利用PASCO力传感器测向心力的大小,用调速电机来改变金属小球作圆周运动的角速度,并用霍尔传感器测量电机的转速,金属小球的质量和小球的旋转半径则定量改变。新的实验装置能定量地探究向心力的大小F与质量m、角速度ω和半径r之间的关系,实验结果精确度高,演示效果明显,方便师生使用和操作,值得推广。     

用传感器探究影响向心力大小的因素

针对传统探究向心力 F大小与质量m、角速度ω和半径r之间关系的实验存在的不足,重新设计了实验装置,该实验装置利用PASCO力传感器测向心力的大小,用调速电机来改变金属小球作圆周运动的角速度,并用霍尔传感器测量电机的转速,而金属小球的质量和小球的旋转半径则可以定量改变,由此可定量探究向心力的大小 F与质量m、角速度ω和半径r之间的关系。     

关于向心力公式验证和物态变化实验的改进

一、在向心力公式验证实验中,我们把实验装置略作改进,效果较好。实验装置如图1。     

Development of a Unique, High Precision Linear Motor Integrated Air Slide Table, and Its Application to Laser Beam Writers

This paper reports on the development of a unique, high precision linear motor integrated air slide table for precise positioning and its application to laser beam writers for photo-mask pattern-making. The air slide table takes advantage of the balance between the air bearing’s levitating and magnetic forces. A brushless linear motor and a high resolution linear encoder are integrated into the table. The unique construction of the device results in a very compact package with excellent accuracy. The basic characteristics of the air slide table are evaluated. The device is applied to a laser beam writer, which must be capable of rendering minute and precise patterns for photo-masking equipment. Examples are given including optical devices such as wave guides and Fresnel zone plates which were fabricated and evaluated. Experimental data is given to show that the Fresnel zone plate fabricated here can be used to focus a laser beam to the theoretical limit, just like a standard refractive lens.     

New optical devices for surface roughness measurements

This paper describes two optical devices: one device is capable of measuring real-time the surface roughness of the magnetic coating in the production process in the range of 5 to 40 nm (RMS) and the other device is designed for table measurements. Both devices are easy-to-install and easy-to-use.     

The role of multielectrode geometry in the generation of pulsedintense electron beams in preionization-controlled open-endedhollow-cathode transient discharges

High-voltage hollow-cathode glow discharges are used more and more to generate intense, pulsed electron beams. Such intense electron beams can be produced with high efficiency in preionization-controlled open-ended hollow-cathode transient discharges (PCOHC). This novel discharge is initiated by a low-current dc preionization discharge. The beam parameters are similar to those of the electron beam generated in pseudospark discharges. In this work, we present some measurements of the parameters for the electron beam generated by using a multielectrode (multigap) system instead of the single-gap device in this PCOHC configuration. This kind of multielectrode device was already used in pseudosparks to improve the intensity and collimation of the extracted beam. By using the multigap instead of the single gap, the total beam current (100-120 A) and the energetic part of the beam current (peak current 60-90 A and electron energies higher than approximately 3 keV) were substantially increased. However, the energy spectrum of the fast component has a large fraction of electrons at lower energies (4-10 keV for 26 kV breakdown voltage) when a multigap device is used instead of the single-gap configuration. A comparison between the single-gap and multigap PCOHC-produced pulsed intense electron beam is made too. The differences between the high-power pulsed electron beams produced in single-gap and multigap PCOHC configurations seem to be due to different developments of beam generation phases     

Temperature-controllable spin-polarized current and spin polarization in a Rashba three-terminal double-quantum-dot device

We propose a Rashba three-terminal double-quantum-dot device to generate a spin-polarized current and manipulate the electron spin in each quantum dot by utilizing the temperature gradient instead of the electric bias voltage. This device possesses a nonresonant tunneling channel and two resonant tunneling channels. The Keldysh nonequilibrium Green's function techniques are employed to determinate the spin-polarized current flowing from the electrodes and the spin accumulation in each quantum dot. We find that their signs and magnitudes are well controllable by the gate voltage or the temperature gradient. This result is attributed to the change in the slope of the transmission probability at the Fermi levels in the low-temperature region. Importantly, an obviously pure spin current can be injected into or extracted from one of the three electrodes by properly choosing the temperature gradient and the gate voltages. Therefore, the device can be used as an ideal thermal generator to produce a pure spin current and manipulate the electron spin in the quantum dot.     

法拉第电磁转动实验装置的改进

对法拉第电磁转动实验进行了改进,用铜盘代替水银并设计了转子,制作单根导线电动机,该电动机适宜在中学物理课堂教学中使用.     

Virtual long-period gratings

A theoretical prediction of a new fiber grating structure is presented. This new device is achieved when a high-birefringence fiber is heavily twisted. It behaves like a long-period grating, but its spectral response can be controlled with the input state of polarization of the light. Since there is no permanent index change, but the index change is instead a product of the polarization evolution along the fiber, this device is called a virtual long-period grating.     

空气密度与气体普适常量测量实验的改进

对测量空气密度和气体普适常量实验装置进行改进,用圆柱形有机玻璃密度瓶代替玻璃密度瓶,用高精度指针式真空表代替热偶真空规式真空计,利用橡胶管和密度瓶接口处的缓慢增气特性来改变空气压强,用电子物理天平称量气体质量,改进后的装置较适合学生实验.     

HL-2A装置YAG激光汤姆逊散射测量电子温度的初步结果

 叙述了激光汤姆逊散射的实验原理,介绍了HL-2A装置上改进后的激光汤姆逊散射系统。高脉冲功率Nd：YAG激光光源发出的1 064 nm的激光能很好地满足测量等离子体电子散射光的要求,硅雪崩光电二极管和窄带干涉滤波片组成的多色仪的使用,大大提高了散射光的测量效率。数据处理方法采用按测量误差进行权重分析的查表法,提高了数据处理的速度。最后介绍了各种放电条件下的单空间点电子温度的测量结果。     

基于数字微镜技术的阿达玛变换近红外光谱仪

构建了一个基于数字微镜技术的新型阿达玛变换近红外光谱仪.光学信号采用光纤引入,以光栅作为分光元件,利用数字微镜代替传统的机械式阿达玛模板进行光学编码调制,使用单点InGaAs红外探测器检测调制后的光信号,通过快速阿达玛解码还原出原始光谱.通过实验检验了光谱仪的分辨率、信噪比、稳定性以及谱图获取速度等指标.实验结果表明,...     

Trinary signed-digit arithmetic using an efficient encoding scheme

The trinary signed-digit (TSD) number system is of interest for ultrafast optoelectronic computing systems since it permits parallel carry-free addition and borrow-free subtraction of two arbitrary length numbers in constant time. In this paper, a simple coding scheme is proposed to encode the decimal number directly into the TSD form. The coding scheme enables one to perform parallel one-step TSD arithmetic operation. The proposed coding scheme uses only a 5-combination coding table instead of the 625-combination table reported recently for recoded TSD arithmetic technique.