基于平板电脑和STM32的多波长自动旋光仪软件设计

旋光度是反映物质旋光性质的指标,通过测定旋光度,可分析物质的浓度、含量、纯度等。SGW-5多波长自动旋光仪利用平面偏振光和法拉弟磁光效应测量旋光物质在特定检测波长和温度下的旋光度。为了满足SGW-5的功能需要,采用了带WINCE嵌入式系统的平板电脑和STM32单片机相结合的硬件系统,并对该系统进行软件设计。该软件设计在几个方面有一定特点,达到了仪器的性能指标要求。     

新型激光旋光仪测量方法的研究与实现

旋光仪多用于制糖业中含糖量的测定,它在食品医药、生命科学、有机化工和高等院校教学实验等领域也有广泛的应用。近年来,基于光学旋光法的无创血糖检测技术也得到了不断地发展。现设计了一种新型激光旋光仪,采用曲线拟合的方法确定起偏器和检偏器的正交位置,与传统旋光仪中采用电子检测部分驱动反馈机制调整电机转角控制系统来寻找正交位置相比,理论上能提高测量精度。搭建了实验装置,采用白砂糖溶液作为样品对整个装置的效果进行了测试,并进行了性能分析。实验结果表明,所设计的新型激光旋光仪测量系统能够实现旋光度的测量。     

地磁线圈对陀螺的修正技术

针对陀螺作为惯性测量系统测量飞行体姿态的重要器件存在零点漂移误差的问题,本文提出使用地磁线圈测量飞行体的旋转角速度,根据磁线圈输出信号的特征点或变化周期对陀螺测得的信号进行修正.详述了利用线圈的磁通量变化测量飞行体飞行姿态的原理,并由法拉第电磁感应定律推导出飞行体旋转角速度的计算公式.     

基于锁相技术和磁光调制的旋光角度检测

根据法拉第磁光效应和锁相基本原理,研究了经磁光调制后的偏振光通过旋光物质后的偏转情况,分析了透射光信号中的与调制频率相同的基频信号和二倍于调制频率的倍频信号。通过对基频幅值和倍频幅值进行比较,提出了一种测量旋光角度的计算方法,根据旋光角和磁偏角两者之间的关系,提出了一种用标准石英管来标定法拉第磁光效应中磁偏角大小的方法,并对其进行了实验研究,证明了这种测量方法的可行性。     

基于小波分析的单个线圈靶速度测量

小波变换具有空间局部化性质，因此可利用小波变换的模极大值点检测动态测量信号的突变点。提出了用单个线圈靶测量水下弹丸初速的原理及方法，由实弹射击实验获得的线圈靶信号，利用小波变换分析了弹丸穿越线圈靶时产生的电动势，建立了弹丸穿越线圈靶时的时间间隔t及运动弹丸速度的计算方法，并与双线圈靶弹丸初速测试结果进行了比对，证明了该方法的可行性。     

Wzz—1S数字式自动旋光仪的校正与修理

<正> 1.概述 旋光仪是测定物质旋光度(角度)的仪器,通过旋光度的测定,可分析物质的浓度、含量和纯度。如果将旋光度值转换成国际糖度,仪器便成了糖度旋光仪,或叫旋光糖量计。因此,仪器广泛应用于制糖、制药、石油、食品、化工、医疗等生产、检验和科研部门。 上海物理光学仪器厂新生产的Wzz—lS数字式自动旋光仪和Wzz—lSS数字式自动糖度旋光仪,便是这一类仪器。     

一种提高容积式油耗仪可靠性的新方法

针对传统容积式油耗仪可靠性差、测量精度低的问题,提出了一种利用浮球遮光来检测油面信号的新方法,并介绍了该方法的测量原理和液面信号检测原理。     

基于DSP的偏振光位移传感器

提出了一种新型偏振光直线位移传感器的DSP实现。基于光的偏振特性、马吕斯定理和法拉第旋光效应，采用同光源双光路检测，实现了大量程直线位移的测量。     

金属涂覆多模光纤小电流传感器设计

常见的光纤电流传感器是基于法拉第旋光效应，主要用于高压大电流的测量且所用传感光纤为单模保偏光纤。利用多模光纤的微弯效应设计一种强制型小电流光纤传感器，通过检测光纤末端输出光束的光能量的变化 来实现小电流的检测。     

基于SIPM的旋光色散波长测量方法

提出了一种利用旋光色散进行波长测量的方法。采用高灵敏度的硅光电倍增管(SIPM)探测线偏振光通过旋光物质和无旋光物质时的输出光强随步进电机旋转而发生的变化,由此测出旋光物质的比旋光度,从而根据比旋光度的色散特征方程求出对应光源波长。大量实验证明,该波长测量装置的精度为1nm,标准差为0.06nm,该波长检测方法具有良好的可行性与稳定性,并且该测量装置具有结构简单、易于调节等特点。     

Evaluation of the Faraday angle by numerical methods and comparison with the Tore Supra and JET polarimeter electronics

On the Tore Supra tokamak, a far infrared polarimeter diagnostic has been routinely used for diagnosing the current density by measuring the Faraday rotation angle. A high precision of measurement is needed to correctly reconstruct the current profile. To reach this precision, electronics used to compute the phase and the amplitude of the detected signals must have a good resilience to the noise in the measurement. In this article, the analogue card's response to the noise coming from the detectors and their impact on the Faraday angle measurements are analyzed, and we present numerical methods to calculate the phase and the amplitude. These validations have been done using real signals acquired by Tore Supra and JET experiments. These methods have been developed to be used in real-time in the future numerical cards that will replace the Tore Supra present analogue ones.     

Faraday cup with nanosecond response and adjustable impedance for fast electron beam characterization

A movable Faraday cup design with simple structure and adjustable impedance is described in this work. This Faraday cup has external adjustable shunt resistance for self-biased measurement setup and 50 Ω characteristic impedance to match with 50 Ω standard BNC coaxial cable and vacuum feedthroughs for nanosecond-level pulse signal measurements. Adjustable shunt resistance allows self-biased measurements to be quickly acquired to determine the electron energy distribution function. The performance of the Faraday cup is validated by tests of response time and amplitude of output signal. When compared with a reference source, the percent difference of the Faraday cup signal fall time is less than 10% for fall times greater than 10 ns. The percent difference of the Faraday cup signal pulse width is below 6.7% for pulse widths greater than 10 ns. A pseudospark-generated electron beam is used to compare the amplitude of the Faraday cup signal with a calibrated F-70 commercial current transformer. The error of the Faraday cup output amplitude is below 10% for the 4-14 kV tested pseudospark voltages. The main benefit of this Faraday cup is demonstrated by adjusting the external shunt resistance and performing the self-biased method for obtaining the electron energy distribution function. Results from a 4 kV pseudospark discharge indicate a "double-humped" energy distribution.     

方波磁光调制测量在航天器对接中的应用

为了精确测量航天器对接过程中最终逼近段航天器间的滚转角,设计了基于方波磁光调制的滚转角测量系统。利用法拉第磁致旋光效应并结合马吕斯定律,建立了方波磁光调制后输出信号的模型;通过分析输出信号的特点,推导了输出信号与滚转角之间的关系方程;利用滚转角变化过程中输出信号的增减性组合去除了方程的增根,最终得到了基于方波磁光调制的滚转角测量模型。仿真结果表明:文中提出的方法理论测量精度高,可测量-90～90°间的滚转角,优于传统方法。此外,利用方波信号调制具有数据采集简单、信号处理难度低等优势,是实现高精度大范围测量航天器间滚转角的一种新方案。     

Design of far-infrared three-wave polarimeter-interferometer system for the J-TEXT tokamak

A multichannel three-wave far-infrared polarimeter-interferometer will be constructed on the J-TEXT tokamak (R=1.05?m, a=0.27?m, B(T)≤3?T, and I(P)≤350?kA) for current density profile and electron density profile measurements. The system will adopt the three-wave polarimeter configuration which was first introduced on RTP. Three 432.5?μm HCOOH lasers pumped by three CO(2) lasers separately will be adopted, which could generate high output power, nearly 50 mW at each cavity. Two of them will be counter-rotating circularly polarized to probe the Faraday angle, while the third laser will be used as a local oscillator to get the phase shift caused by electron density. Excellent port access (600×76?mm(2)) and high laser power would promise a profile measurement across the whole plasma section with good signal quality. A high-speed digital phase comparator with a few (～2)?μs temporal resolution will be developed, so that fast changes of current or density profile could be measured. Six channels will be installed in the first stage.     

Charge measurement using an array of Faraday’s Cups on a printed circuit board

An absolute method of measuring charge is to use a Faraday Cup (FC) principle. This study relates to a novel method of measuring charge on a flat substrate, which is coated with charged powder particles. The substrate consists of an array of FC with different dimensions. The sensor is manufactured using flame-retardant printed circuit board (PCB) technology. The objective of this work is to reduce the charge sharing by developing a grounded shield cup around each conductive cup in the array and accordingly increase cup-to-ground capacitance. The results have confirmed that the improved well shielding would provide a more accurate quantitative charge measurement.     

用于高场非对称波形离子迁移谱系统的阵列式微法拉第筒离子检测器

提出了一种可减小高场非对称波形离子迁移谱(FAIMS)系统体积的阵列式微法拉第筒离子检测器,该检测器具有结构简单、稳定性好、噪声小、量程大、可在大气压条件下工作等优点。阵列式微法拉第筒包括栅电极、敏感电极、屏蔽电极3部分,其中敏感电极由数十个直径为200μm的硅圆柱交错排列而成。通过典型的MEMS工艺制作,法拉第筒与平板型FAI MS系统的MEMS工艺完全兼容。Fluent仿真结果表明,这种阵列式的设计,气体运动阻力较小,流场分布有助于载气中离子被充分吸收。与KEITHLEY237电流表级联后,测得阵列式微法拉第筒的噪声水平在0.5 pA以下。对丙酮样本进行了实验测试,结果显示其输出信号为210 pA左右,表明该阵列式微法拉第筒满足FAIMS系统的要求。     

集磁式光纤电流传感器

以法拉第磁光效应为原理的光纤电流传感器因其无爆炸危险、抗高电磁干扰、绝缘性好、价格便宜、结构简单、质量轻等优点,将成为传统电磁式互感器的替代产品。文中介绍一种集磁式光纤电流传感器,说明该传感器的工作原理,并且给出传感头的结构、信号处理电路,最后对其测试性能进行了必要的讨论,证明此类传感器具有成本低、稳定性高、使用灵活等特点。     

Calibration system with cryogenically-cooled loads for cosmic microwave background polarization detectors

We present a novel system to calibrate millimeter-wave polarimeters for cosmic microwave background (CMB) polarization measurements. This technique is an extension of the conventional metal mirror rotation approach, however, it employs cryogenically-cooled blackbody absorbers. The primary advantage of this system is that it can generate a slightly polarized signal (～100 mK) in the laboratory; this is at a similar level to that measured by ground-based CMB polarization experiments observing a ～10 K sky. It is important to reproduce the observing condition in the laboratory for reliable characterization of polarimeters before deployment. In this paper, we present the design and principle of the system and demonstrate its use with a coherent-type polarimeter used for an actual CMB polarization experiment. This technique can also be applied to incoherent-type polarimeters and it is very promising for the next-generation CMB polarization experiments.