Microlaser with Ramsey Separated Fields Cavity

In a novel microlaser configuration with Ramsey separated-field cavity, we investigate a two-level atomic beam interacting with a single-mode high-Q Ramsey cavity, which is composed by two separated resonators. By using the well-known Ramsey cavity, one can recover the characters of microlaser even with a high flux atomic beam.     

Evaluation of Influence of Multiple Scattering Effect in Light-Scattering-Based Applications

The extinction cross sections of a system containing two particles are calculated by the T-matrix method, and the results are compared with those of two single particles with single-scattering approximation. The necessity of the correction of the refractive indices of water and polystyrene for different incident wavelengths is particularly addressed in the calculation. By this means, the volume fractions allowed for certain accuracy requirements of single-scattering approximation in the light scattering experiment can be evaluated. The volume fractions calculated with corrected refractive indices are compared with those obtained with fixed refractive indices which have been rather commonly used, showing that fixed refractive indices may cause significant error in evaluating multiple scattering effect. The results also give a simple criterion for selecting the incident wavelength and particle size to avoid the ＇blind zone＇ in the turbidity measurement, where the turbidity change is insensitive to aggregation of two particles.     

尿中L-精氨酸及其甲基化产物的高效液相色谱法测定

用反相高效液相色谱邻苯二甲醛（OPA）柱前衍生荧光检测，可以直接同时分离和定量尿中的L－精氨酸（L－Arg),N^G,N^G－二甲基精氨酸（ADMA）和N^G,N^G-二甲基精氨酸（SDMA）。方法的平均回收率大于97％；含量的上对标准差低于4．6％；而保留时间的相对标准差低于0．32％；信噪比为3：1时，其检测限为0．3pmol.用该方法测定了正常人和肾肾衰者尿中L－Arg,ADMA和SDMA的含量。     

Incorporation Behaviour of Arsenic and Phosphorus in GaAsP／GaAs Grown by Solid Source Molecular Beam Epitaxy with a GaP Decomposition Source

The incorporation behaviour of arsenic and phosphorus in the GaAsP ternary alloy under phosphorus-rich conditions is studied based on the incorporation coefficient model and the growth diffusion model combined with the alloy composition data obtained by high resolution x-ray diffraction analysis. It is found that As adatoms have longer surface lifetime and longer migration length than those of P adatoms, which leads to an arsenic incorporation efficiency much higher than that of phosphorous. With the increase of arsenic flux, the surface lifetime of arsenic adatoms decreases due to the competition of As adatoms. The detailed analysis and discussion are given here.     

晚期HEMP作用下铁路牵引供电系统GIC算法研究

高空核爆电磁脉冲晚期效应（E₃）会引起地磁场剧烈变化并形成地面感应电场。感应电场等效为激励源与地面长距离导体和大地构成回路,产生地磁感应电流 （GIC）。GIC可引起牵引供电系统中变压器直流偏磁,从而严重威胁牵引供电系统的安全运行。本文基于平面波理论、分层大地电导率模型并结合牵引供电系统的电路模型,提出E₃作用下的牵引供电系统GIC算法,并以带回流线的直接供电方式的铁路牵引供电系统为例,首次计算了系统GIC情况。结果表明,该供电方式下牵引供电系统中的GIC远大于系统中变压器等设备的耐受值,为进一步研究E₃作用下牵引供电系统效应及我国铁路设备选型、灾害防治等提供支撑。     

振动时效的动应力判据

采用多元非线性回归分析方法，求得振动时效试验中动应力σｄ，载荷次数ｎ和残余应力当量ｋ对消应力效果εｖ的经验方程。从而实现用动应力现场速测来定量评定振动时效工艺效果。本文主要介绍动应力判据方程的建立方法及其应用。     

压电液相免疫传感信号放大技术研究进展

本文简要介绍了压电液相生物传感器的理论基础,并对近年来压电液相免疫传感技术中所采用的质量效应信号放大技术和非质量效应信号放大技术的研究进展作系统综合评述。引用文献46篇。     

天然黄酮类化合物清除羟基自由基的活性研究

采用分光光度法测定了黑沙蒿中黄酮类化合物清除羟基自由基的能力,以IC50值作为评价指标,初步探讨了黄酮类化合物清除羟基自由基的活性与结构之间的关系,为开发利用黑沙蒿提供了科学依据.     

红外光谱结合线阵列检测技术研究聚合物分散液晶膜分子取向

采用偏振红外光谱和变温红外光谱研究聚合物分散液晶膜中液晶分子取向随外加电场及温度的变化.利用线阵列检测技术表征了聚合物与液晶界面处的成分分布.结果表明,线阵列检测技术能够快速而直观地给出成分分布图,通过该成分分布图可以解释PDLC在温度场作用下分子取向的变化.