用于脉冲功率装置测量的混合式高压分压器

为准确测量脉冲放电电压,提出了固液混合式高压分压器的原理与结构,并进行了标定和实验测试。用简化模型分析了分压器系统的理想响应条件,讨论了两级分压的衰减特性,提出了控制误差的方法。通过负载标定,得到分压器脉冲电压频率响应大于2.9 MHz,最长脉冲宽度40 s,分压比(或衰减系数)为2.60 kV/V,测量误差小于5%。该高压分压器具有造价低、制作易,同时适于ns到s级脉冲电压的测量等优点,可以在实验室中得到应用。     

微弱电流高精度自动测量系统

为了实现辐射探测中对微弱电流信号的实时准确测量,设计了一套微弱电流测量系统。介绍了系统的工作原理,及I-V转换和放大单元的低噪声抗干扰设计、-△模数转换技术和单片机程序的设计。系统通过USB与计算机进行通信,计算机应用软件可以完成采集频率和量程控制、数据处理、显示和存储等功能。经过验证,该系统能满足10-13~10-3 A的大动态微弱电流测量,分辨力为四位半, 能自动量程判断,具有较高的精度和稳定性,已成功应用于辐射探测实验。     

激光烧蚀制备分布反馈式有机激光器件

采用激光烧蚀的方法结合激光全息技术,直接在高分子聚合物MEH-PPV薄膜表面烧蚀光栅结构,制备了分布反馈式有机激光器。这一方法具有工艺简单、光栅参数的可控性和重复性好等优点。器件MEH-PPV的膜厚是400 nm。利用波长为355 nm的Nd-YAG纳秒激光器进行单脉冲烧蚀,获得的光栅周期和光栅高度分别为370 nm和 100 nm。利用飞秒激光放大器作为泵浦源激射DFB激光器件,得到激射阈值约为182 μJ·cm^-2·pulse^-1,光谱的波峰约在609 nm处,半高宽为4.2 nm。通过改变两光束的夹角获得了周期为360, 370, 380, 390 nm的光栅,它们对应的激光波峰分别为602.91, 609.24, 613.26, 619.01 nm。     

字节全加器及其在无线电测控系统中的应用

对全加器概念进行了推广，并在此基础上给出了使用字节全加器网络的无线电抗干扰算法。通过在实际的无线电测控系统中的应用，结果表明该算法具有良好的无线电抗干扰效果。     

掺铒光纤激光器自混合理论与微振动位移测量

利用线形掺铒光纤激光器搭建了一种新型光纤传感测量系统来测量微振动位移.采用条纹计数法分析自混合干涉信号,实验显示扬声器的振幅与驱动电压成很好的线性关系.该实验装置结构简单、成本低.实验结果表明,用该传感系统来进行振动位移测量,信号稳定,方法简单、迅速.     

Facile Fabrication of PBS/CNTs Nanocomposite Foam for Electromagnetic Interference Shielding

In order to reduce the pollutants of environment and electromagnetic waves, environment friendly polymer foams with outstanding electromagnetic interference shielding are imminently required. In this paper, a kind of electromagnetic shielding, biodegradable nanocomposite foam was fabricated by blending poly (butylene succinate) (PBS) with carbon nanotubes (CNTs) followed by foaming with supercritical CO₂. The crystallization temperature and melting temperature of PBS/CNTs nanocomposites with 4 wt % of CNTs increased remarkably by 6 °C and 3.1 °C compared with that of pure PBS and a double crystal melting peak of various PBS samples appeared in DSC curves. Increasing the CNT content from 0 to 4 wt % leads to an increase of approximately 3 orders of magnitude in storage modulus and nearly 9 orders of magnitude in enhancement of electrical properties. Furthermore, CNTs endowed PBS nanocomposite foam with adjustable electromagnetic interference (EMI) shielding property, giving a specific EMI shielding effectiveness of 28.5 dB cm³/g. This study provides a promising methodology for preparing biodegradable, lightweight PBS/CNTs foam with outstanding electromagnetic shielding properties.     

分子信标用于p53 mRNA的体外定量检测

根据p53基因的序列设计并合成了能特异性检测p53 mRNA的分子信标(MB), 发展了一种快速定量测定细胞内总RNA提取物中p53 mRNA的方法. 采用鼻咽癌(CNE2)细胞系和经RNA干扰技术降低p53基因表达的CNE2-p53RNAi细胞系, 抽提总RNA并用MB检测, 验证了MB的检测对象是p53 mRNA. 将该方法应用于多种肿瘤细胞内p53基因表达水平的分析, 表达变化趋势与经典的mRNA分析方法RT-PCR检测结果相符. 在此基础上, 用MB对5-氟尿嘧啶(5-Fu)处理的肺腺癌细胞(A549)进行了p53 mRNA的体外定量检测, 结果表明采用MB能够快速地获知该药物对细胞内p53 mRNA表达影响的信息.     

ICP－AES中内标法的应用研究 Ⅲ．用内标法校正基体干扰

通过观测基体对分析元素发射强度的干扰情况，分析干扰机制，从而确定用来校正基体干扰的内标元素与分析元素的匹配条件。实验结果表明，只要选择合适的内标元素，可以校正基体干扰。     

Spectral and non-spectral interferences in inductively coupled plasma mass-spectrometry

Inductively coupled plasma mass spectrometry of environmental and biological samples is often hampered by spectral and non-spectral interferences. Spectral interferences, caused by the limited resolution of the quadrupole mass spectrometer, can be eliminated in a variety of ways. For their identification inspection of a signal versus carrier gas flowrate is useful. Anion exchange allows the removal of most S and Cl containing compounds, which are at the origin of the majority of spectral interferences. Matrix modification, for example the addition of ethanol and subsequent optimization of the gas flow rates in a number of cases enables the reduction of the interferences to insignificant values. Often a mathematical correction based on isotopic signal ratios can be applied. Non-spectral interferences can be divided in reversible, that is occurring while the sample is being measured, and irreversible matrix effects, that is clogging of the nebulizer and sampling orifices or deposition on the torch or in the ion lens stack. The errors associated with non-spectral interferences can be eliminated by appropriate calibration procedures, adapted sample preparation or limitation of the amount of sample delivered to nebulizer, plasma and sampling devices, for example by the application of flow injection. Applications of all the elimination procedures are described for the analysis of sea-water, estuarine water, soil and sewage extracts, percolate water, urine, serum and wine.     

Resolving the copper interference effect on the stripping chronopotentiometric response of lead(II) obtained at bismuth film screen-printed electrode

As copper(II) is a common ion in a variety of analytical samples, its effect on the stripping response of lead(II) at bismuth film screen-printed carbon electrode (BFSPCE) was investigated. The study was conducted using a screen-printed three-electrode system (working, counter and reference electrodes), with the carbon-working electrode plated in situ with bismuth film. Copper present at significant concentration level in samples was found to affect the sensitivity of the electrode by reducing the constant current stripping chronopotentiometric (CCSCP) response of lead(II). Recovery of the lead stripping response at the BFSPCE in the presence of copper was obtained when 0.1 mM ferricyanide was added to the test solution. The ferricyanide added circumvents the detrimental effect of copper(II) by selectively masking the copper ions by forming a complex. The analytical utility of the procedure is illustrated by the stripping chronopotentiometric determinations of lead(II) in soil extracts.