全光纤光子集成器件及系统

本对全光纤光子集成器件与系统进行了较为全面地综述,结合我们的工作,对目前的研究热点：光纤光栅,光纤激光器,光纤放大器,光纤光栅分插器与传感器等诸多光子器件以及由这些器件组成的波分复用通信系统进行了介绍和评述,一些新成果和新进展表明,这些光子器件与系统在当今和未来的光通信中将发挥重要作用。     

Dual-wavelength distributed Bragg reflector semiconductor laser based on a composite resonant cavity

We report a monolithic integrated dual-wavelength laser diode based on a distributed Bragg reflector (DBR) composite resonant cavity. The device consists of three sections, a DBR grating section, a passive phase section, and an active gain section. The gain section facet is cleaved to work as a laser cavity mirror. The other laser mirror is the DBR grating, which also functions as a wavelength filter and can control the number of wavelengths involved in the laser action. The reflection bandwidth of the DBR grating is fabricated to have an appropriate value to make the device work at the dual-wavelength lasing state. We adopt the quantum well intermixing (QWI) technique to provide low-absorption loss grating and passive phase section in the fabrication process. By tuning the injection currents on the DBR and the gain sections, the device can generate 0.596 nm-spaced dual-wavelength lasing at room temperature.     

基于低相干光的阵列透镜束匀滑技术研究

基于激光加载的材料状态方程的实验研究对靶面光强分布的均匀性及稳定性提出了极高的要求,靶面光强的上述两大特性在很大程度上决定了实验结果的精度和可重复性.本文针对传统窄带高相干激光装置在激光加载材料状态方程实验中表现出的靶面光强均匀性和光强分布稳定性两方面可能存在的问题,提出了基于宽带低相干激光,利用消衍射阵列透镜联合诱导非相干技术的束匀滑方案,并重点分析了波前相位畸变对靶面不均匀性及稳定性的影响.模拟结果表明,该方法明显降低了靶面不均匀性,提高了对波前相位畸变的包容度,获得了均匀、稳定的光强分布.统计分析显示,焦斑强度分布极差和不均匀性与波前相位畸变均方根梯度相关性较强.因此,可以根据统计结果以及实验对焦斑强度分布的要求,给出波前相位畸变的容差范围,对状态方程实验中激光驱动器参数的设计与优化具有指导意义.     

Novel delay-distribution-dependent stability analysis for continuous-time recurrent neural networks with stochastic delay

<正>In this paper,the problem of delay-distribution-dependent stability is investigated for continuous-time recurrent neural networks(CRNNs) with stochastic delay.Different from the common assumptions on time delays,it is assumed that the probability distribution of the delay taking values in some intervals is known a priori.By making full use of the information concerning the probability distribution of the delay and by using a tighter bounding technique(the reciprocally convex combination method),less conservative asymptotic mean-square stable sufficient conditions are derived in terms of linear matrix inequalities(LMIs).Two numerical examples show that our results are better than the existing ones.     

129I加速器质谱分析研究

通过对129I加速器质谱(AMS)分析中影响敏度和准确度各种参数的研究,如靶电极制备、压样、靶样中辅助介质（Matrix）的选择及使用比例等,优化了用于3 MV加速器质谱仪的SO-110型离子源的条件参数,确定129I-AMS测量的最佳靶电极材料为Cu,最佳的辅助介质为Nb粉末,Nb与AgI样品的最佳体积比为3∶1。在此条件下可以获得稳定且持续的I-束流进行测量129I/127I原子比值,实验测得西安加速器质谱仪的129I/127I本底值为1.5210-14。     

Dosimetry in sonochemistry: the use of aqueous terephthalate ion as a fluorescence monitor

The generation of HO radicals by acoustic cavitation in water was monitored by their reaction with terephthalic acid (TA) anion to produce fluorescent hydroxyterephthalate ions using a cleaning bath (38kHz) and a probe system (20, 40 and 60 kHz) as different sources of ultrasound. When using the ultrasonic bath as a source of energy for sonochemical studies, the shape of the reaction vessel is important. In the case of HO production from water (50 cm³), reaction in a conical flask (100 cm³) produces 2.75 times more radicals than a round-bottomed flask of the same capacity. The fluorescence yield (fluorescence intensity/ultrasound dosage) obtained using the conical flask and ultrasonic bath was similar to that for a probe operating at 40 kHz on the same volume of solution. For a probe system operating at 20, 40 and 60 kHz the greatest sonochemical efficiency was attained at the highest of these frequencies (60 kHz). For the probe system the fluorescence yield is directly proportional to power input and the concentration of TA. The fluorescence yield decreases as the temperature is increased.     

磁场中多原子极性晶体中体极化子的基态能量

研究磁场中多原子极性晶体中体极化子的性质,采用线性组合算符法,分别导出强,弱耦合情形下体极化子的基态能量。     

Monoterpenoid Indole Alkaloids with Promoting Neurite Growth from Tabernaemontana divaricata

Main observation and conclusion Phytochemical investigations on Tabernaemontana divaricata led to the isolation of seven undescribed monoterpenoid indole alka-l...     

高温吸热管内超临界CO2传热特性的数值模拟

研究超临界CO2在高温吸热管内的传热特性是将其应用于聚光太阳能热发电技术中的基础.本文对此进行了数值模拟研究,分析了流体温度、流动方向、系统压力、质量流率和热流密度对对流传热系数和Nu数的影响.结果表明:高温区(800—1050 K)的对流传热系数和Nu数受流动方向和系统压力的影响均很小,但都随着质量流率的增大以及热流...