基于虚拟仪器技术和网络的综合实验控制系统设计

为实现大型物理实验现场复杂多样的仪器控制,分析了物理实验的特点、过程、环境及仪器控制功能需求,利用虚拟仪器技术、计算机网络技术和数据库技术,建立了一套集成硬件和软件的综合控制管理信息系统,实现记录系统中示波器状态远程批量设置及波形数据自动采集、控制探测系统的高压电源并发加压或退压、保障各测试项目间测试仪器之间时间关联、监控UPS电量和远端现场图片或视频状态。给出了系统的关键的设计思路,列举了某型示波器控制的通用控制代码。结果表明,系统达到了一人总控或多人分权控制实验过程中多种多台仪器的目标,方便快捷地实现不同品牌不同类型示波器的相同功能。     

Thermodynamical behavior of E′ centers in quartz from sediments: Potential for paleothermometry and geochronometry

The thermodynamical behaviors of E′ centers in 8 quartz samples from core XJ33-2-1 recovered in the Zhujiang Mouth Basin were measured by electron spin resonance (ESR) technique. The E′ ESR spectral intensity of samples before any laboratory treatment was measured and expressed asI ₁. The samples were then annealed at 300°C or 350°C for 60 min. The E′ ESR spectral intensity measured after this procedure is expressed asI ₂. The ratios ofI ₁, toI ₂ for the samples increase with the sample depth (from 320 to 3972 m), showing that there is a correlation between this ratio and the storage temperature of samples. Therefore the ratio ofI ₁/I ₂ can be used as an ESR paleothermometer. Besides the temperature, we must take into account the period of time for which the samples have been buried since their deposition, because we find that the ratiosI ₁/I ₂ (from 0.293 to 0.941) are closely related to the sediment ages (from 1.5 to 27.5 Ma), with a correlation coefficient of 0.98 or 0.99 obtained by linear or exponential regression, respectively. This relation can be explained by the increase of E′ center concentration in quartz samples with the sedimentation age.     

LD-pumped passively Q-switched Nd:YVO4 infrared and green lasers

A laser diode directly end-pumped, passively Q-switched Nd:YVO₄/Cr:YAG laser is presented in this paper. With 600 mW incident pump laser, Q-switched 1064 nm laser with an average power of 138 mW, pulse width of 19.8 ns, repetition rate of 170.1 kHz and peak power of 40.96 W is obtained. When a KTP crystal was inserted into the cavity, Q-switched 532 nm laser with an average power of 56 mW, pulse width of 28.4 ns, repetition rate of 118.2 kHz and peak power of 16.7 W is obtained at last.     

Data Offline Calibration for the BES-Ⅱ TOF System

Data offline calibration and reconstruction for the BES-Ⅱ TOF system are reported in this paper. After applying calibration constants to correct the measured raw data, a the resolution of 180 ps is obtained for the new TOF system. The power of charged particle identification is improved. The momentum for the 3σπ/K separation goes up to 0.93 GeV/c.     

β－环糊精对Pb（Ⅱ）－四（－3溴－4－磺酸基苯基）卟啉显色反应增敏作用的研究

本文研究了β－环糊槽（β－ＣＤ）对Ｐｂ（Ⅱ）－四（－３溴－４－磺酸基苯基）卟啉（ｍ－Ｂｒ－ＴｐｐＳ４）显色体系的增敏作用，提出了高灵敏度测定痕量铅的分光光度新方法。显色体系的表观摩尔吸光系数为２．５×１０５Ｌ·ｍｏｌ－１·ｃｍ－１。铅在０－１０μｇ／２５ｍＬ范围内符合比耳定律。稳定性好，操作简便，快速。本方法适用于人发和白酒等试样中铅的测定。回收率在９４％－１０３％。     

衍射光学元件的解析分析方法

从波动光学传播的菲涅尔衍射出发，探讨一次光学转换形成任意要求的图形的问题。导得两平行传播平面的函数关系，从而在确定像面分布的条件下可以逆求出原始面的振幅与倍相分布。文中给出了几个实例，充分表明这是有实用价值的一种衍射光学元件设计方法。     

Laser-induced etching of polycrystalline Al2O3TiC in KOH aqueous solution

Laser-induced etching of polycrystalline Al₂O₃TiC material by a tightly-focused cw Ar ion laser has been investigated in a KOH solution with different concentrations. It is found that the KOH concentration can strongly affect the etching quality where low KOH concentration can result in rough and irregular patterns. Laser-induced etching of polycrystalline Al₂O₃TiC in a KOH solution is found to be a photothermal reaction in which a threshold laser power exists. With an appropriate set of etching parameters, well-defined grooves can be obtained with clean side walls and with an etching rate up to several hundred micrometers per second. The etching behavior is also found to depend on laser scanning direction. It is also found that the grains in the polycrystalline Al₂O₃TiC material play an important role in the etching dynamics and etching quality. This etching process is believed to be applicable to the formation of a slider surface of magnetic heads in the future.     

Study of synthetic diamonds by dynamic nuclear polarization-enhanced13C nuclear magnetic resonance spectroscopy

Four I_b-type synthetic diamond crystals were studied by dynamic nuclear polarization (DNP)-enhanced high resolution solid state¹³C nuclear magnetic resonance (NMR) spectroscopy. The home built DNP magic-angle-spinning (MAS) NMR spectrometer operates at a field strength of 1.9 T and the highest DNP enhancement factor of synthetic diamonds came near to 10³. Comparing with I_b-type natural diamonds, the¹³C NMR linewidths of synthetic diamonds in static spectra are broader. The¹³C spin-lattice relaxation time and DNP polarization time of synthetic diamond are shorter than those of I_b-type natural diamond. From the hyperfine structure of the DNP enhancement curve, four kinds of nitrogen-centred free radicals could be identified in synthetic diamond.     

傅里叶红外光谱法鉴别部分胡椒属生药的研究

利用共有峰率和变异峰率双指标,以胡椒属七种药用植物的红外指纹图谱为依据,计算出所测样品的共有峰率和变异峰率。建立了胡椒属七种药用植物共有峰率和变异峰率双指标序列,结果揭示了胡椒属七种药用植物的亲缘关系。中药海风藤与石南藤、大叶蒟根茎的共有峰率均在77%以上,变异峰率均在30%以下,此三种胡椒属药用植物亲缘关系较近;海风藤与胡椒根茎、十八症根的共有峰率在61%左右,亲缘关系稍远;海风藤与蒌叶根茎的共有峰率仅为44%。亲缘关系较远。利用红外二阶导数谱图,可以鉴别中药海风藤及其伪品石南藤、十八症根、大叶蒟根茎、胡椒根茎等品种。傅里叶红外光谱法可以对样品进行无损处理,不需要对药材进行复杂的提取分离过程即可提供化合物的官能团、类别、氢键等信息。该法能从整体水平分析谱图特征峰,具有分析速度快,重现性好,非破坏性和样品量小,制样简单,专属性强,节约成本,保护环境等优点。可以解决中药海风藤因资源短缺,伪品较多,鉴别困难等问题,也可为临床用药的安全、有效提供保障。傅里叶红外光谱法为胡椒属药用植物亲缘关系的探讨和真伪鉴别提供了一种新方法。符合中药向综合分析和整体分析发展的趋势。     

基于半导体光放大器的干涉型器件中噪声特性的分析

分析了基于半导体光放大器(SOA)的干涉仪分别处于“开”、“关”两种工作状态时的输出信噪比及噪声指数,发现当干涉仪处于“开”态时输出信噪比有所恶化,并导出了附加噪声因子的表达式。实验结果进一步证明了理论分析的正确性。