新型紫外吸收光谱法测量化学需氧量的实验研究

采样系统在使用紫外吸收(UV)光谱法测量水质化学需氧量(COD)的仪器中是非常重要的组成部分。目前采样系统中普遍地使用样品池,但其窗片上附着的污染物难以完全去除,导致测量误差较大。介绍一种UV法检测COD的新型实验装置,该装置的取样系统中使用了一种新设计的喷嘴,它可以形成厚度为9 mm的稳定的水柱,克服样品池的缺点。在水质成分相对稳定的情况下,应用该装置检测实际废水并与标准方法比对,相对误差不超过10％,获得较好的一致性。     

表面处理对FED薄膜型金属电极性能的影响

针对场致发射显示器（FED）金属薄膜与玻璃附着力的特性,提出一种超声清洗和UV清洗相结合技术应用于薄膜型金属电极表面清洁处理。本文分析了超声清洗和UV清洗的基本原理．利用绿灯观测装置和大面积视频显微镜检测不同超声清洗时间和频率以及UV清洗对金属电极质量的影响,利用场发射测试系统测试经表面处理前后的金属薄膜电极性能。实验结果表明,FED金属薄膜电极在32kHz超声清洗10min,Uv光清洗5min后,电极表面干净,无尘埃和有机污物,金属膜层不脱落。显示器场发射性能稳定。     

基于SPA-SVR的紫外光谱水质污染物含量解耦预测方法

快速、精准地实现水体中多种污染物的耦合干扰解析及含量检测对野外水质实时监测具有重要意义。针对紫外光谱法同步检测化学需氧量（COD）和浊度时存在特征耦合及谱峰重叠干扰，进而严重影响检测精度的问题，提出了一种连续投影算法结合支持向量回归的水质污染物含量解耦预测方法。采用连续投影算法对水质样本的紫外吸收光谱特征波长进行筛选，消除无关冗余数据以提高模型迭代速率和精度。基于多分类支持向量机思想对支持向量回归算法进行多回归拟合改进，实现COD和浊度的紫外光谱耦合解析和含量的同步预测。通过实际水样检测验证，结果表明：耦合解析前的预测均方根误差改进率达到76%，最大相对误差均降低至4%以内，优于同类方法的检测精度，该研究对紫外光谱法水质多耦合参数检测应用具有参考价值。     

激光诱导荧光探测气溶胶装置的研制及实验研究

基于激光诱导荧光原理研制出一套激光诱导荧光探测气溶胶的装置。该装置采用Nd:YAG脉冲激光器产生355 nm波长脉冲激光,经过引导后进入样品池,激发出的荧光被系统收集后进入高分辨率光栅光谱仪,得到样品的荧光光谱图。选用还原型辅酶I（NADH）和核黄素两种典型的生物荧光物质对系统的性能进行测试,在355 nm激光激发下,获取了还原型辅酶I（NADH）、核黄素荧光光谱图;研究了样品浓度对于荧光光谱强度的影响,结果表明在低浓度范围荧光强度与浓度呈线性关系;考查了激光能量对荧光强度的影响,在一定能量范围荧光强度与激光能量呈线性关系,但当激光能量达到一定值后荧光强度会发生饱和。该装置所建立的生物性物质荧光数据库有利于了解和掌握生物荧光特性,对于进一步实现生物气溶胶远距离探测具有重要意义。     

差动式光声检测及其应用

本文介绍了差动式光声检测技赤，设计出了适于这种检测的光声池。差动式光声检测就是采用两个性能基本一致的光声池串联地放在同一光路上进行检测.前面的光声池称为B池（参考池），后面的光声池称为A池（样品池）。为了消陈光声池的本底信号，利用A池本底信号减去B池本底信号，通过调节电路的差动式方法，使（A～B）池本底信号趋于零. 利用差功式检删技术，在CO2激光发射波长内测定了各种红外窗口材料及某些气体的吸收系数、硅烷磷烷的激光光声光谱及缓冲气体对光声信号的影响等。     

预（光）刻伺服录写装置中基于计算机控制的激光声光调制系统

预（光）刻伺服录写装置是我们正在开发的用于提高硬盘存储器容量的一种高技术设备。论述了该装置所使用的激光声光调制系统，提出并实现了基于计算机控制的，采用单一声光调制器在该装置上进行光功率稳定、光强控制及光脉冲控制的系统，给出了一种有效的数字滤波算法。     

基于生物发光技术的细菌总数快速检测仪

针对细菌总数现场检测需求，设计了一种基于ATP（三磷酸腺苷）生物发光技术的细菌总数现场快速检测仪。传统方法检测细菌总数需要2-3天，而利用ATP生物发光技术可在30min之内完成检测，大大提高了检测速度。本检测仪选取H5773-02型光电倍增管作为光电转换器件以检测微弱光信号，该光电倍增管的工作波长范围为330-850nm，峰值检测波长为500nm，ATP生物发光波长为550nm，两者基本一致，使检测仪具有较高的测量灵敏度。采用流动注射技术，在加入被测样品后分别向样品池中加入检测试剂。由于样品池被密闭在检测腔中，因此可有效减小外界光对测量结果的影响，同时也减小了人为加样对检测重复性的影响，提高检测重复性。利用本检测仪对浓度在10^-6-10^-14mol/L内的ATP样品进行了检测。实验表明，测量结果具有明显梯度，测试时间小于400s时，与标准样品浓度间的线性相关系数达到0.986。设计的细菌总数快速检测仪具有检测速度快、重复性高、操作简单等优点，可适用于食品卫生与安全、环境检测等领域。     

激光多普勒电泳应用于淋巴细胞分析的研究

激光多普勒电泳是利用激光的多普勒效应与医学中的电泳方法相结合发展起来的一种新技术。该装置主要由激光器、电极、样品池、光电倍增管和信号处理机等部分组成。当光束聚焦在样品池两电极间时,由于带电颗粒在电场作用下的运动,使入射激光频率产生频移。发生频移的激光由光电倍增管接收,并送入信号处理机,从而获取与样品有关的信息。 我们观测到,正常人淋巴细胞的激光多普勒光     

插入式超声化学反应器的设计与仿真研究

超声辅助水样消解技术实现了水质多参数检测的快速性、准确性,而声化学反应器在超声消解法中起到了关键性作用。从理论方面分析了影响超声波在声化学反应器中能量传播的主要因素是反应器结构和几何尺寸;采用ANSYS软件仿真,设计了一种变幅杆插入式声化学反应器。通过MATLAB软件进行声场仿真分析,与槽式相比,插入式具有降低能量损耗,提高传播效率的优势。设计实验证明,基于插入式化学反应器的超声辅助快速检测方法测得标准邻苯二甲酸氢钾(KHP)溶液的化学需氧量(COD)值同国标法测得的COD值非常接近,准确度在-9.2%~4.4%,且测量重复性好,周期较短。该方法更有利于水质在线检测技术。     

基于多次反射样品池的TDLAS逃逸NH3检测研究

时域激光吸收光谱(TDLAS)技术具有高选择性、 高准确性优点,为逃逸NH₃的在线检测提供了可靠的技术手段。本文利用TDLAS 系统分别在White和Herriott 两种样品池中对浓度为(10～100)×10－6的NH₃进行检测, 采集得到其二次谐波光谱,比较 了两种样品池测量结果,分析对比两种样品池的优缺点。实验显示,Herriott样品池的噪声 要大,根据光谱曲线的标准偏差得到White样品池最低检出限为1.21×10－6 ,Herriott样品池 的检测限为1.61×10－6。结果表明,Herriott样品池更适合 恶劣环境现场应用,能够满足逃逸NH₃的痕量检测要求,适合在线监测。     

Resolution Enhancement Technology:Integrated Process Solutions using OPC

DUV lithography, using the 248 nm wavelength, is a viable manufacturing option for devices with features at 130 nm and less. Given the low kl value of the lithography, integrated process development is a necessary method for achieving acceptable process latitude. The application of assist features for rule based OPC requires the simultaneous optimization of the mask, illumination optics and the resist.Described in this paper are the details involved in optimizing each of these aspects for line and space imaging.A reference pitch is first chosen to determine how the optics will be set. The ideal sigma setting is determined by a simple geometrically derived expression. The inner and outer machine settings are determined, in turn,with the simulation of a figure of merit. The maximum value of the response surface of this FOM occurs at the optimal sigma settings. Experimental confirmation of this is shown in the paper.Assist features are used to modify the aerial image of the more isolated images on the mask. The effect that the diffraction of the scattering bars (SBs) has on the image intensity distribution is explained. Rules for determining the size and placement of SBs are also given.Resist is optimized for use with off-axis illumination and assist features. A general explanation of the material' s effect is discussed along with the affect on the through-pitch bias. The paper culminates with the showing of the lithographic results from the fully optimized system.     

Cost-effective test solutions for smart card and other integrated flash applications

From its emergence in the late 1980s as a lower cost alternative to early EEPROM technologies, flash memory has evolved to higher densities and speedsand rapidly growing acceptance in mobile applications.In the process, flash memory devices have placed increased test requirements on manufacturers. Today, as flash device test grows in importance in China, manufacturers face growing pressure for reduced cost-oftest, increased throughput and greater return on investment for test equipment. At the same time, the move to integrated flash packages for contactless smart card applications adds a significant further challenge to manufacturers seeking rapid, low-cost test.     

An improved parallel thinning algorithm with two subiterations

The parallel thinning algorithm with two subiterations is improved in this paper. By analyzing the notions of connected components and passes, a conclusion is drawn that the number of passes and the number of eight-connected components are equal. Then the expression of the number of eight-connected components is obtained which replaces the old one in the algorithm. And a reserving condition is proposed by experiments, which alleviates the excess deletion where a diagonal line and a beeline intersect. The experimental results demonstrate that the thinned curve is almost located in the middle of the original curve connectivelv with single pixel width and the processing speed is high.     

Theoretical analysis of the relationship between the Brillouin gain coefficient and the strain in the optical-fiber sensors

The relation between the power of the Brillouin signal and the strain is one of the bases of the distributed fiber sensors of temperature and strain. The coefficient of the Bfillouin gain can be changed by the temperature and the strain that will affect the power of the Brillouin scattering. The relation between the change of the Brillouin gain coefficient and the strain is thought to be linear by many researchers. However, it is not always linear based on the theoretical analysis and numerical simulation. Therefore, errors will be caused if the relation between the change of the Brillouin gain coefficient and the strain is regarded as to be linear approximately for measuring the temperature and the strain. For this reason, the influence of the parameters on the Brillouin gain coefficient is proposed through theoretical analysis and numerical simulation.     

Novel fiber-optical interferometer with miniaturized probe for in-hole measurements

Today, micro-system technology and the development of new MEMS （Micro-Electro-Mechanical Systems） are emerging rapidly. In order for this development to become a success in the long run, measurement systems have to ensure product quality. Most often, MEMS have to be tested by means of functionality or destructive tests. One reason for this is that there are no suitable systems or sensing probes available which can be used for the measurement of quasi inaccessible features like small holes or cavities. We present a measurement system that could be used for these kinds of measurements. The system combines a fiber optical, miniaturized sensing probe with low-coherence interferometry, so that absolute distance measurements with nanometer accuracy are possible.     

Study of waveguide coupling efficiency in hybrid silicon lasers

This paper presents a new method to increase the waveguide coupling efficiency in hybrid silicon lasers. We find that the propagation constant of the InGaAsP emitting layer can be equal to that of the Si resonant layer through improving the design size of the InP waveguide. The coupling power achieves 42% of the total power in the hybrid lasers when the thickness of the bonding layer is 100 nm. Our result is very close to 50% of the total power reported by Intel when the thickness of the thin bonding layer is less than 5 nm. Therefore, our invariable coupling power technique is simpler than Intel＇s.     

Curved crystal spectrometer for the measurement of X-ray lines from laser-produced plasmas

In order to diagnose the laser-produced plasmas, a focusing curved crystal spectrometer has been developed for measuring the X-ray lines radiated from a laser-produced plasmas. The design is based on the fact that the ray emitted from a source located at one focus of an ellipse will converge on the other focus by the reflection of the elliptical surface. The focal length and the eccentricity of the ellipse are 1350 mm and 0.9586, respectively. The spectrometer can be used to measure the X- ray lines in the wavelength range of 0.2-0.37 nm, and a LiF crystal （200） （2d = 0.4027 nm） is used as dispersive element covering Bragg angle from 30° to 67.5°. The spectrometer was tested on Shengnang- Ⅱ which can deliver laser energy of 60-80 J/pulse and the laser wavelength is 0.35 μm. Photographs of spectra including the 1 s2p ^1P1-1s^2 ^1S0 resonance line（w）, the 1s2p ^3P2-1s^2 1S0 magnetic quadrupole line（x）, the 1s2p ^3P1-1 s^2 ^1S0 intercombination lines（y）, the 1 s2p ^3S~1-1 s^2 ^1S0 forbidden line（z） in helium-like Ti Ⅹ Ⅺ and the 1 s2s2p ^2P3/2-1 s622s ^2S1/2 line（q） in lithium-like Ti Ⅹ Ⅹhave been recorded with a X-ray CCD camera. The experimental result shows that the wavelength resolution（λ/△ 2） is above 1000 and the elliptical crystal spectrometer is suitable for X-ray spectroscopy.     

Preparation and Characterization of TaN ALD Precursors

High purity organic-tantalum precursors for thin film ALD TaN were synthesized and characterized.Vapor pressure and thermal stability of these precursors were studied.From the vapor pressure analysis,it was found that TBTEMT has a higher vapor pressure than any other published liquid TaN precursor,including TBTDET,TAITMATA,and IPTDET.Thermal stability of the alkyl groups on the precursors was investigated using a 1H NMR technique.The results indicated that the tertbutylimino group is the most stable group on TBTDET and TBTEMT as compared to the dialkylamido groups.Thermal stability of TaN precursors decreased in the following order:TBTDET ＞ PDMAT ＞ TBTEMT.In conclusion,precursor vapor pressure and thermal stability were tuned by making slight variations in the ligand sphere around the metal center.     

Electronic Structure of Semiconductor Nanocrystals

This paper reviews our recent development of the use of the large-scale pseudopotential method to calculate the electronic structure of semiconductor nanocrystals, such as quantum dots and wires, which often contain tens of thousands of atoms. The calculated size-dependent exciton energies and absorption spectra of quantum dots and wires are in good agreement with experiments. We show that the electronic structure of a nanocrystal can be tuned not only by its size,but also by its shape. Finally,we show that defect properties in quantum dots can be significantly different from those in bulk semiconductors.     

A rigorous proof of MIMO channel capacity’s increase with antenna number

It is well known that adding more antennas at the transmitter or at the receiver may offer larger channel capacity in the multiple-input multiple-output（MIMO） communication systems. In this letter, a simple proof is presented for the fact that the channel capacity increases with an increase in the number of receiving antennas. The proof is based on the famous capacity formula of Foschini and Gans with matrix theory.