基于FPGA的自适应调节光栅光谱仪

采用FPGA作驱动和控制电路的核心,以简单的逻辑电路实现了CCD曝光时间和可编程放大器增益的自适应控制.在此基础上开发了能将信号幅度自动调节到合适范围的光栅光谱仪,采用USB总线实现系统与上位机的通讯,由LabVIEW平台开发出的应用程序进行光谱数据存储、谱图显示和处理.     

自制CCD光谱仪

根据多年教学经验，把传统光栅光谱仪用现代技术进行改造，自制了一套CCD光谱仪．此仪器克服了传统光谱研究的方法——照相法、光电法的缺点，并能同时采集各个波长点的数据，串行地传输给计算机．由计算机对这些数据进行图像处理，实现了光谱的快速分析．实践证明：该仪器比购买的多功能光栅光谱仪在教学中有更多的独特优点。     

宽谱段光纤光谱仪

为满足野外现场矿物分析、遥感地面验证光谱分析等的需要,研制了实现光谱覆盖范围在400～2 500 nm的宽谱段光纤光谱仪,介绍了仪器研制过程中的光学、机械与电子学设计。光学系统采用了光栅分光的水平反射式光路,对于不同的光谱探测谱段,采用了三路线阵探测器在光谱面的3个方向立体交错放置进行探测;用CPLD(complex programmable logic device)实现对三路线阵光电器件时序逻辑信号的发生与驱动;采用14位高速ADC进行数模转换;采用USB2.0实现通讯。仪器体积小、光谱分辨率高、信号质量和测量速度等方面均达到了满意效果,测试结果表明,仪器实现了宽谱测量,光谱数据理想。     

基于LabVIEW的光纤光栅自动检测及分析系统

为了便于光纤布喇格光栅传感系统的自动化测试及使用,利用光谱仪的远程控制端口,采用LabVIEW语言开发了具有友好界面的Q8384光谱仪远程应力自动化测试系统.将光纤布喇格光栅嵌入封装于钢梁中,并利用应力试验机进行应力加载,通过LabVIEW测试系统采集并处理实验数据,结果表明该系统功能与设计预期吻合,可以实现对被测量数据的实时监测及存储.测试设备易于操作,并且避免了对光谱仪的人为直接操作,可以延长光谱仪的使用寿命.     

透射式光栅光谱仪摄谱性质的研究

本文从理论和实验上探讨了透射光栅的光栅参数和实验几何条件对于光栅的衍射效率、色散、光谱对称性及散射本底的影响,对于这些摄谱性质的了解,将有助于实验数据的分析。     

组合式数显直读光栅光谱仪

常用光谱仪分为棱镜光谱仪、光栅光谱仪和傅立叶光谱仪。棱镜光谱仪自由光谱范围广,但角色散不大且非线性;傅氏光谱仪利用面光源,集光本领强,但完成傅氏变换需大量计算。光栅光谱为正弦光谱,谱线细,分辨本领高;配以滤波片,可扩大自由光谱范围,避免不同级次谱线重叠;改用闪耀光栅可提高光强利用率。目前教学科研多采用光栅作色散元件,但这些光谱仪结构复杂,均需通过繁琐计算或标准谱内插等方法读数。     

自制简易光谱仪测量护眼灯显色指数

利用狭缝、反射光栅和CCD自制了一台光谱仪,光线从狭缝入射,经过反射光栅,CCD采集衍射光谱,从而获得光源光谱数据,根据光源显色指数计算公式编写相应程序,导入光谱数据即可得出光源显色指数,实现了利用自制光谱仪测量光源显色指数的实验目的,拓展了光谱仪的实际应用。该实验装置简单,实验成本较低,适合公共课物理实验教学,有利于大学生深入了解光谱仪原理。     

针孔透射式光栅光谱仪衍射效率的理论模拟

本文介绍了最新建立的针孔式透射光栅光谱仪的性质,对其衍射效率进行了理论模拟和分析,并利用有关实验数据计算了光栅的重要结构参数.     

遮阳护肤品防紫外线性能实验开发

利用组合式多功能光栅光谱仪、澳钨灯和吸收池,对遮阳护肤品进行光谱特性分析,对样品的基线和透射谱进行对比,同时配合对样品透过率的分析,可以得到样品的防紫外线性能,从而开发出一个非常受学生欢迎的综合性应用性实验。     

遮阳品防紫外线性能的实验分析

利用组合式多功能光栅光谱仪、溴钨灯和吸收池,对遮阳品进行光谱特性分析.对3种样品的基线和透射谱进行了对比,并配合对样品透过率的分析,得到样品的防紫外线性能,从而开发出一个非常受学生欢迎的、将物理实验与实际生活联系起来的实验.     

Study of fully developed wind wave spectrum by application of quantum statistics

The spectrum of fully developed wind waves is studied by application of the method of quantum statistics. A particle picture of water waves is introduced as an analogy of wave–particle duality. “Water wave particles” are conceived which are similar to phonons for elastic waves in solids. However, due to the property of wave breaking, the number of “water wave particles” in a quantum state is restricted. The spectrum of fully developed wind waves is studied on the basis of the maximum entropy principle. The similarity law of fully developed wind wave spectrum is proved. In the high frequency range, the spectral form is in agreement with the result of observations. In the particle picture, a saturated spectrum is introduced which is in conceptual consistency with the saturated spectrum introduced by Phillips in the wave picture, and the form of which is the same as Phillips’. It is further shown that in the high frequency range the spectrum is only half saturated for fully developed wind waves. The frequency downshifting phenomenon which cannot be explained by wave theory is explained in the particle picture.     

Penning阱存储离子的高分辨分析

根据Penning阱中存储和探测离子的原理,研究改善离子谱分辨率的有效措施,发现离子谱的分辨率与LC振荡回路的Q值、阱中离子的密度及LC回路的谐振频率等因素有关.实验中,谐振频率为480千赫兹,Q在120左右,电子束流在40微安左右,真空度合适时,得到了较高分辨率的离子谱.最后对离子谱进行了辨认,离子分别是H+3,H+5,H+6,H+7.     

A program for the interactive analysis of positron lifetime spectra on personal computers with the aid of screen graphics

A personal computer program has been developed for use in the interactive analysis of positron lifetime spectra with the aid of a graphic display. The multi-exponential function model is used to fit a spectrum by the linear least-squares method. The spectrum displayed on the screen is altered simultaneously as the lifetime components are stripped one by one from the longest-lived to the shortest. The merit of this code is that it provides the user with a visual feedback at any stage of the analysis. Moreover, the obtained model parameters of the spectrum can be used as initial estimates for the POSITRONFIT program used for final analysis.     

Spectroscopy of persistent hole burning in the quantum dot-matrix system: Quantum-confined stark effect and electroabsorption

A theory of persistent spectral hole burning is developed. Within a simple, exactly solvable model (a cubic potential well with infinitely high walls in a uniform electric field), the energy spectrum and the rate of electron-hole pair generation are determined with due regard for the effect of the field induced in this case owing to the spatial separation of electrons and holes. The dependence of the energy spectrum on the field vector orientation relative to the symmetry axes of a quantum dot is studied. An expression describing the shape of the differential spectrum is derived.     

软X射线能谱定量测量技术研究

采用每毫米1000线的自支撑透射光栅配上背照射软X射线CCD(charge coupled device)组成了透射光栅谱仪,利用北京同步辐射装置(BSRF)3W1B光束线软X射线实验站上X射线源分别对透射光栅的衍射效率和软X射线CCD的响应灵敏度进行了准确的实验标定,获得了150eV到1500eV能区的绝对衍射效率和响应灵敏度的实验结果;同时在国内外研究工作的基础上,发展了自己的透射光栅衍射效率理论计算模型和X射线CCD响应灵敏度计算模型,开展了相应的理论计算和实验标定结果比对工作,理论和实验符合较好,     

Mössbauer spectra processing using neural networks

A Mössbauer spectrum can be understood as a sum of Lorentz functions. The aim of this work is to develop an automated algorithm for Mössbauer spectra processing. The required output of this algorithm is the number of Lorentz functions contained in the spectrum and the values of parameters of these functions, i.e. values of their amplitudes, positions and halfwidths. For this purpose a modified brute-force method was used. There are tested all possible combinations of parameters of the Lorentz functions whether they properly fit measured spectrum or not. A set of parameters having the best fit with the spectrum is the output of this method. Testing all possible combinations takes a huge computational power so an optimization process was developed to speed up the computational process. This is achieved by decreasing the number of tested combinations. The optimization process is based on a mathematical analysis and neural network processing. An evolutional algorithms were used for proper setting up of the neural weights.     

一种中药指纹图谱自适应提取方法及软件实现

基于VC++6.0和OpenCV1.0的自主开发界面,应用光谱图像检测原理,设计出了一套适用于中药光谱图像检测系统并能快速获取中药荧光指纹图谱的数据处理软件。同时,成功将该软件应用于自主研发的中药光谱图像检测系统中作为控制及处理模块,并利用其对鹿茸等中药材进行了实际检测,证明了系统的可靠性和准确性。该软件可以同时绘制多达8个中药样品或者8个样品间任意组合的光谱立方体在同一坐标中拟合的特征光谱曲线,从而对样品进行真伪鉴别和品种鉴定,具有操作简便,处理速度快,兼容性好等特点。     

一种宽能谱多球中子谱仪的研制

利用蒙特卡罗程序MCNPX模拟计算了纯聚乙烯球和加入辅助材料的聚乙烯球对不同能量中子的响应函数曲线,使用计算出来的响应函数作为U-M-G软件解谱所需输入文件。研发了一套专门为此多球谱仪进行数据采集的放大甄别一体化电路,该电路可为SP9管提供900 V的工作高压,甄别阈设为0.5 V,总的放大倍数为200倍。使用研制的Bonner球谱仪对已知源强的Pu-Be中子源进行能谱测量,测量结果显示解出的能谱数据与实际Pu-Be源中子能谱较为符合,实验结果验证了该套多球谱仪可用于测量Pu-Be能区的中子谱。Neutron response of Bonner spheres which include pure polyethylene and polyethylene with auxiliary material was calculated with Monte Carlo code MCNPx, the calculated response was used as the input le of U-M-G code for neutronspectrum unfolding. A special screening of ampli cation integrated circuits was developed, which can provides high voltage 900 V working for the SP9 tube, the screening threshold is set to 0.5 V and total magni cation is 200. Neutron energy spectrum of a Pu-Be source were measured with the developed Bonner spheres spectrometer,good agreement was found in the measured result of the spectrum datasolutionand the real spectrum, which indicated that the multi-sphere spectrometer was reliable in the neutron measurement at energy region of Pu-Be neutron source.     

用太阳光谱测量空气中NO2浓度的方法研究

根据Noxon方法 ,利用NO2 在 430— 45 0nm范围内的吸收特性 ,测量空气中NO2 的浓度 .介绍了一种利用光学差分吸收原理 ,以太阳光为光源 ,二极管阵列为探测器 ,黄山光明顶上的太阳光谱为参考光谱测量大气中NO2 浓度的新光学方法 .