光谱法测定室内空气中甲醛浓度

为了对甲醛的浓度进行快速而有效的检测，设计了一套光栅式光谱检测系统。该系统主要包括光学系统、光电信号采集系统和计算机处理系统。系统硬件电路包括前置放大滤波电路、A/D转换电路及单片机的数据采集和发送电路。对酚试剂分光光度法测定空气中甲醛浓度的实验条件进行了研究，分析了影响实验结果的因素，得出了光谱检测实验的实验结果，并对相关结论进行了分析和论证。通过所设计的系统，可直接测出甲醛分析液的透射光光谱，从而得出相应的甲醛浓度。     

基于ODMR的高信噪比磁强计及荧光采集集成系统设计

为了解决传统的荧光光谱采集系统与光探测磁共振(optically detected magnetic resonance，后文简称ODMR)光谱采集系统存在的搭建繁琐、检测样品聚焦精度较低、采集系统之间转换困难以及ODMR光谱采集信号信噪比和采集精度较低的问题，设计了基于光纤传感的荧光采集与ODMR光谱采集转换系统。通过光纤将激发光源电路、微波传感天线、光纤传感器、显微聚焦光路、PD(photodetector)放大电路、信号处理模块以及荧光光谱仪各模块进行耦合集成，为信号处理的软件提供硬件部分支持。在软件部分，通过开源程序编写实现信号数据处理以及光谱成像功能，利用PD放大电路对数据进行初步处理之后，在软件部分通过信号处理模块进行进一步处理，数据以图谱形式呈现，并且最终磁灵敏度达到0.51 nT/Hz^1/2。     

宽光谱光源的功率因数校准及稳压电路设计

设计了宽光谱光源稳定电路,介绍了L6561功率因数校准电路和UC3843稳压电路的设计.将单端反激式电路与L6561功率因数校正器相结合设计PFC电路,改善了传统电路功率因数低、电流谐波大的问题.L6561功率因数校准电路输出稳定的直流电压作稳压电路的24V输入电压,UC3843和TLC271设计稳压电路,可以输出300mA高精度电流.     

基于红外吸收光谱的瓦斯气体浓度检测技术

针对现有矿井瓦斯传感器的缺点,基于红外光谱吸收原理,采用差分吸收技术设计了红外瓦斯气体浓度探测系统.该系统采用单光路吸收气室和单光路双波长探测技术,利用差动放大电路为核心的微弱信号处理电路实现瓦斯浓度输出信号的检测,并采用线性关系式拟合瓦斯浓度和输出电压的关系曲线,实现了对瓦斯浓度的全量程精确探测.实验表明,该系统的测...     

基于CPLD和单片机的多光谱数字相机下位机设计

介绍一种基于单片机和CPLD结合的多光谱CCD相机下位机系统的设计实现.利用CPLD扩展多光谱相机下位机的输出控制端口.分别用图形输入法和VHDL硬件编程语言作为CPLD的输入方式,使之成为一个多用途I/O端口扩展芯片,既简化了电路设计,减小了电路尺寸,降低了电路功耗,又便于修改配置,非常适合于多光谱遥感相机下位机系统应用.     

基于红外吸收光谱的瓦斯气体浓度检测技术

针对现有矿井瓦斯传感器的缺点,基于红外光谱吸收原理,采用差分吸收技术设计了红外瓦斯气体浓度探测系统。该系统采用单光路吸收气室和单光路双波长探测技术,利用差动放大电路为核心的微弱信号处理电路实现瓦斯浓度输出信号的检测,并采用线性关系式拟合瓦斯浓度和输出电压的关系曲线,实现了对瓦斯浓度的全量程精确探测。实验表明,该系统的测量误差小于2%,具有很高的测量精度,具备了煤矿应用的基础。     

基于SERS的食品中乌洛托品快速检测系统设计

基于表面增强拉曼光谱技术(surface enhanced Raman spectroscopy, SERS),研制出对食品中乌洛托品进行现场快速分析检测的系统。检测系统由多功能前处理模块、拉曼光学模块、嵌入式主控模块三部分组成,实现了待测样品的前处理,拉曼光谱数据的产生、收集、传输与处理。其中,多功能前处理模块将化学实验中经常用到的离心、超声、挥发三种功能集于一体,精简了前处理实验中需要用到的设备;拉曼光学模块采用探头光路与分光系统合为一体的整体式设计,并在探头光路中使用数值孔径为0.6的非球面透镜,同时利用交叉非对称Czerny-Turner结构对分光系统进行了设计;嵌入式主控模块采用自主研发的FPGA+ARM双核心主控电路,配合CCD的制冷电路与驱动电路,搭载μC/OS-Ⅲ操作系统,实现了对CCD上拉曼光谱数据的采集、传输与处理。利用柠檬酸钠制备纳米金(liquid colloidal gold nanoparticle,LCP-1)作为增强试剂对乌洛托品进行检测,将乌洛托品的拉曼特征峰选取在1 047 cm-1处,对乌洛托品标准品和含有乌洛托品的腐竹与米粉样品进行检测实验,实验结果表明所设计的检测系统可以实现对乌洛托品的准确识别,对乌洛托品标准品的检测限可达0.01 mg·L-1,对腐竹和米粉样品中乌洛托品的检出限可达0.5 mg·L-1,检测时间小于20 min,实现了食品中乌洛托品的现场快速检测。     

基于CCD器件的农药荧光检测系统的研究

根据一些有机农药受到紫外光激发能够发出荧光的光谱特性,设计了基于荧光分析的农药浓度检测装置。系统以脉冲氙灯为激发光源,采用光纤进行传输和探测荧光,利用CCD线阵实现了光电信号的转换,设计了相应的弱信号处理电路,并由微机进行存储和显示。利用该系统实现了对西维因农药的荧光光谱特性的检测。实验结果表明,在激发波长319nm、荧光波长647nm时,最小检测浓度为5×10-7μg/L,西维因浓度范围在0~120.0μg/L之间时系统具有较好线性关系,线性相关系数r为0.9996(S/N=5)。该系统能满足荧光测量的需要。     

光谱学 光谱仪器

TH744．1 2005020911 脉冲激光光谱测试仪的设计=Design of a pulse laser spec- trum testing system[刊,中]／曹益平(四川大学光电科学技 术系．四川,成都(610064)),刘晓丽…//光电工程．- 2004,31(8)．-41-44 设计了一种基于ISP技术的线阵CCD的驱动电路和 高速脉冲光谱数据采集卡,建立了一套智能化脉冲激光光 谱测试系统。该系统主要由分光系统、CCD传感器、光脉 冲同步信号发生器、数据采集卡及计算机等部分组成。     

基于HgCdTe红外探测器的微弱信号检测电路设计

 被动动态傅里叶变换红外光谱（FTIR）仪可用于周围环境红外辐射的光谱分析,其中红外信号检测是光谱仪中的重要组成部分。基于高信噪比、高灵敏度、温漂小和抗干扰能力强的电路设计原理,采用滤波电源供电,使用高速低噪声高精度的运算放大器,通过合理的电路布局和元器件选择来设计红外信号检测电路。在大气环境和室内气室的实验条件下,红外信号检测电路组成的红外光谱仪对目标气体进行红外遥感,并对实验结果进行了分析和探讨。实验结果表明：在系统中运行的检测电路具有较高的信噪比和较好的稳定性,测量精度高,可实现对大气环境的红外遥感。     

The voltage-current relationship and equivalent circuit implementation of parallel flux-controlled memristive circuits

A flux-controlled memristor characterized by smooth cubic nonlinearity is taken as an example, upon which the voltage-current relationships （VCRs） between two parallel memristive circuits - a parallel memristor and capacitor circuit （the parallel MC circuit）, and a parallel memristor and inductor circuit （the parallel ML circuit） - are investigated. The results indicate that the VCR between these two parallel memristive circuits is closely related to the circuit parameters, and the frequency and amplitude of the sinusoidal voltage stimulus. An equivalent circuit model of the memristor is built, upon which the circuit simulations and exper/mental measurements of both the parallel MC circuit and the parallel ML circuit are performed, and the results verify the theoretical analysis results.     

蔡氏电路的研究与制作

在非线性电路中蔡氏电路是迄今为止产生复杂动力学行为的最为有效和较为简单的电路之一。从软件仿真和电路制作两个角度分别对蔡氏电路的特性进行了研究,讨论蔡氏电路的工作原理,分别用PSPICE和MATLAB软件仿真出蔡氏电路的相关特性,并制作出硬件电路,给出观察蔡氏电路周期1、周期2极限环及单涡卷和双涡卷混沌吸引子的实验结果,得出了与理论分析一致的结果。对进一步研究和设计专用混沌集成电路及混沌在保密通信中的应用具有积极的意义。     

单相并联谐振变换器输出LC滤波器参数优化

采用在静止直角坐标系中构造虚拟正交电路的方法,推导了单相并联谐振变换器在直接正交(D-Q)旋转坐标系中的等效电路,求解了该等效电路的传递函数;通过仿真验证所推导的D-Q等效电路能够准确地代表原变换器电路。基于阻抗匹配的原则,通过D-Q等效电路的传递函数对单相并联谐振变换器的输出LC滤波器参数进行了优化,达到了输出脉冲电压上升沿时间小于50μs、过冲小于5%、调节时间小于100μs和纹波小于5%的预期指标,验证了采用该方法来优化并联谐振变换器输出LC滤波器参数的可行性。     

Chaotic memristive circuit: equivalent circuit realization and dynamical analysis

In this paper, a practical equivalent circuit of an active flux-controlled memristor characterized by smooth piecewise-quadratic nonlinearity is designed and an experimental chaotic memristive circuit is implemented. The chaotic memristive circuit has an equilibrium set and its stability is dependent on the initial state of the memristor. The initial state-dependent and the circuit parameter-dependent dynamics of the chaotic memristive circuit are investigated via phase portraits, bifurcation diagrams and Lyapunov exponents. Both experimental and simulation results validate the proposed equivalent circuit realization of the active flux-controlled memristor.     

Dynamical characteristics of an HP memristor based on an equivalent circuit model in a chaotic oscillator

To develop real world memristor application circuits,an equivalent circuit model which imitates memductance(memory conductance) of the HP memristor is presented.The equivalent circuit can be used for breadboard experiments for various application circuit designs of memristor.Based on memductance of the realistic HP memristor and Chua's circuit a new chaotic oscillator is designed.Some basic dynamical behaviors of the oscillator,including equilibrium set,Lyapunov exponent spectrum,and bifurcations with various circuit parameters are investigated theoretically and numerically.To confirm the correction of the proposed oscillator an analog circuit is designed using the proposed equivalent circuit model of an HP memristor,and the circuit simulations and the experimental results are given.     

Analysis of the effect of stray capacitance on a charge/discharge-based electrical capacitance tomography system

The measurement circuit of electrical capacitance tomography (ECT) system mainly includes CMOS switches, C/V conversion circuit and Data processing circuit. In order to improve the image reconstruction quality, conversion circuit is very necessary to the small capacitance measurement circuit. A charge/discharge measurement circuit is one of the most suitable for the C/V conversion circuit in ECT. The stray capacitance between the measurement electrodes and earth can be large and have an effect on the capacitance measurement. This paper analyzes this effect, taking into account the ON-resistance of the COMS switch, the unit gain frequency of op-amp, and gain error in the measurement circuit. Finally, it is shown that if the range of stray capacitance is 150 ± 60 pF, overall error would be estimated. Comparing the effects of the circuit parameters, this charge/discharge-based capacitance is effectively stray-immune. It is a more efficient analysis to C/V circuit in ECT and offers a great benefit to information processing.     

QUANTUM FLUCTUATIONS IN A MESOSCOPIC DAMPED LC PARALLEL CIRCUIT IN DISPLACED SQUEEZED FOCK STATE

We study the quantum effects of a damped LC parallel circuit considering its different performance from an RLC series circuit in classical physics. The damped LC parallel circuit with a source is quantized and the quantum fluctuations of magnetic flux and electric charge in the circuit in displaced squeezed Fock state are investigated. It is shown that, as in the RLC series circuit, the fluctuations only depend on the squeezing parameter and the parameters of the circuit components in the damped LC parallel circuit, but the effects of the circuit components on the fluctuations are different in the two circuits.     

基于电流反馈放大器的网格多涡卷混沌电路设计与实现

提出了一种仅用电流反馈放大器实现网格多涡卷混沌系统的方法.首先用电流反馈放大器设计非线性函数电路;再用电流反馈放大器设计网格多涡卷混沌电路,根据混沌吸引子参数确定电路参数,由于电流反馈放大器具有较好的频率特性和端口特性,使该电路的工作频率高、电路结构简单、使用元件少;最后,通过电路仿真验证该方法的可行性.     

Mapping equivalent approach to analysis and realization of memristor-based dynamical circuit

A novel mapping equivalent approach is proposed in this paper, which can be used for analyzing and realizing a memristor-based dynamical circuit equivalently by a nonlinear dynamical circuit with the same topologies and circuit parameters. A memristor-based chaotic circuit and the corresponding Chua’s chaotic circuit with two output differentiators are taken as examples to illustrate this approach. Equivalent dynamical analysis and realization of the memristor-based chaotic circuit are performed by using Chua’s chaotic circuit. The results indicate that the outputs of memristor-based chaotic circuit and the corresponding outputs of Chua’s chaotic circuit have identical dynamics. The proposed approach verified by numerical simulations and experimental observations is useful in designing and analyzing memristor-based dynamical circuits.     

一个新的五阶超混沌电路及其研究

提出一个新的五阶超混沌电路. 该电路由三个线性电感、两个线性电容、一个线性负电阻和二个非线性元件组成,并具有π形的电路结构. 其主要特征是,利用非线性元件的作用来切换电路中的时间常数,使其电压和电流发生急剧变化. 利用负电阻可满足电路局部发散的条件,并且这种电压和电流的急剧变化以及局部发散是该电路产生混沌与超混沌的两个前提条件. 分岔和李雅普诺夫指数计算结果表明,随着分岔参数的改变,电路的振荡机理由周期态演变为混沌态,再由混沌态演变为超混沌态. 设计了五阶超混沌电路,给出了硬件实验结果. 关键词： 超混沌电路 超混沌吸引子 电路实验