线性啁啾变迹及均匀光纤光栅的反射谱分析

该文从理论上研究了线性啁啾变迹光纤光栅及均匀光纤光栅的反射谱，经分析发现，高斯分布的耦合系数具有平滑反射谱，消除旁瓣的作用，啁啾系数的增大使得光栅的反射谱明显变宽，最大反射率降低，利用这个规律，可选择恰当的参量，制作出符合工程要求的光纤光栅，同时也发现均匀“弱”光纤光栅的反射谱具有sa(x)函数的分布特性，在此基础上提出用“弱”光纤光栅做匹配光滤波器的设想。     

基于P-OTDR分布式光纤传感中信息提取的研究

在介绍了P＿OTDR分布式传感基本原理的基础上,深入研究了从测得的背向散射信号中提取出偏振态演化信息的方法.通过数字平均和解卷积提高了信号的信噪比和系统分辨率,为P＿OTDR分布式光纤传感系统的实用化提供了一定的基础.     

差分吸收光谱技术及在大气监测领域中的应用

差分吸收光谱技术(DOAS：Differential Optical Absorption Spectroscopy)是一种光谱监测技术，其基本原理就是利用空气中的气体分子的窄带吸收特性来鉴别气体成分，并根据窄带吸收强度来推演出微量气体的浓度。凭借其低廉且简单的设备装置和出色的监测能力，DOAS技术在大气监测领域内在国外已经被广泛应用。鉴于国内的污染形势的日益严峻及对此新兴技术知识的匮乏。对于DOAS技术的工作原理、浓度反演方法及其在大气研究领域内的应用与发展前景做了较为详细的介绍，为今后在大气监测领域里研究和应用DOAS技术提供了必要的理论知识。     

平面锥形光波导模斑转换器的研究

基于三维有限差分束传输法（FD－BPM）对平面光波导器件中的关键元件之一－平面锥形模斑转换器作了深入的研究，对线性和数种非线性侧面边界的模斑转换器进行了数值仿真和对比，分析了平面锥形模斑转换器侧面边界函数对耦合损耗的影响，以及模斑转换器中模场分布随传输距离的变化，确定了不同长度的平面锥形模斑转换器的最佳侧面边界，指出长度在200－1000μm范围内具有余弦边界的平面锥形模斑转换器性能最佳，并且发现，光纤中的出射光进入模斑转换器以后，光波模式会逐渐发生变化，并最终转化为单模。     

弹流拖动力试验系统关键技术的研究

介绍了弹流拖动力试验系统中的几个关键技术及实施．     

Lightning activity on the central Tibetan Plateau and its response to convective available potential energy

Lightning flash activities on the central Tibetan Plateau have been studied by using the satellite-based Lightning Imaging Sensor(LIS)database from January 1998 to July 2002.The lightning activity shows a clear diurnal variation on the central Plateau.The peak lightning activity appears at about 17:00 which is 3 h earlier than that in Jingxhou,Hubei in the same latitude belt nearby,indicating that the lightning activity is a sensitive indicator of solar heating on the Plateau.The lightning discharge is weaker on the Plateau than Jingzhou.Hubei and other low-altitude continental regions because of the lower convective available potential energy(CAPE)on the Plateau.The CAPE on the Plateau is 12 times lower than that in Jingzhou,Hubei,and 20 times lower than that in the sea-level region,such as Guangzhou and Florida.However,the sensitivity of lightning activity to CAPE changes on the Plateau is up to 30 times more sensitive than other prominent low-altitude regions.     

Measurements of leucocyte membrane elasticity based on the optical tweezers

A 1-μm in diameter polystyrene bead coated with lectin is trapped by optical tweezers whics is formed by a focused laser beam (740nm).A leucocyte adhered to the bottom of sample cell is chosen to close to the trapped bead.When their stable combination is confirmed,the leucocyte is displaced by moving the sample stage.A“tether”is then formed between the trapped bead and the membrane.The force acting on the tether is measured by a detector equipped on the optical tweezers system.The deformation of the membrane is diverse in different contact conditions.When the contact area is small,the tether is very thin and the force on it is 7.4pN(10^-12N),while the tether is much thicker under a larger contact area and its corresponding force is about 14pN.It is presumed that the latter is related to the deformation of cytoskeleton.     

Land vehicle positioning using GPS and dead reckoning

To ensure reliable land vehicle positioning, the Global Positioning System (GPS) is one of the best techniques commonly used in present-day positioning systems. However, GPS signals are not available if line of sight with the satellites is lost. In this respect, the addition of the Dead Reckoning (DR) method to complement the GPS unit would enhance the reliability of land vehicle positioning system. For implementing the DR method, the magnetic sensor and accelerometer are used for obtaining heading and velocity or distance information. Calibration of two sensors' dynamic model and DR algorithm are also introduced in this paper. The test result utilizing the GPS and DR methods is analyzed in this paper. It utilize spositioning information from GPS receiver when GPSsignal is available, otherwise DR is started to compensate GPS outage with the GPS output as the original point. The results showed that the error in east and north produced by the DR algorithm for a short time interval can be limitedwithin an acceptable range.     

液体饱和蒸气压力和温度关系测定仪的研制

用特定材料和巧妙的方法设计制作了安全可靠和密封性好的微型锅炉 ,理论分析和实验证实压力容器(微型锅炉 )的上述性能 .以微型锅炉为基础 ,配以压力、温度传感器及控制电路制成了液体饱和蒸气压力和温度关系测定仪 ,通过对水、无水乙醇的饱和蒸气压力和温度关系的测定 ,证明该仪器在设计压力及温度范围内测得的数据与公认值吻合 ,具有一定的实用价值     

基于Turbo编码和二进制脉冲位置调制的快跳频光码分多址系统

在不考虑噪声和仅考虑散粒噪声两种情况下，分析了Turbo码对二进制脉冲位置调制(BPPM)的快跳频光码分多址(FFH OCDMA)系统性能的影响，并对该系统进行了数值模拟。结果表明，Turbo码对BPPM调制的FFH OCDMA系统性能有明显的改善。