Nonreciprocal Coupling in Asymmetric Dual-Core Photonic Crystal Fibres

The photonic crystal fibre with asymmetric dual cores is shown to attain strongly nonreciprocal coupling of the lightwave propagating along the fibre, for the first time to our knowledge. It is found that the coupling properties can be quite different when the incident position is changed. This kind of fibre could have potential for unidirectional coupler applications in fibre-optic local and metropolitan area networks. We also examine the polarization and wavelength dependence of the coupling nonreciprocity in the asymmetric dual-core photonic crystal fibres.     

基于光纤输出光斑旋转的位移传感器

实验设计了两个光纤环,减小光纤环1的半径使光纤发生宏弯损耗,获得两光斑。此时再压缩光纤环2,发现两光斑整体随光纤环2的受压位移在一定受压范围内表现出了很好的旋转性。通过两光斑旋转角度随光纤环2受压位移的一一对应关系,经实验数据处理获得了光斑角度与线圈受压位移存在一定范围的线性关系。同时实验分析了光纤环2的直径和光纤环2的紧绕圈数对压缩位移灵敏度的影响。     

基于模糊关系的DEM数据信息伪装技术研究

提出一种DEM数据的信息伪装技术。应用Rabin方法生成单向Hash函数，结合波动方程随机生成DEM数据。构造模糊矩阵，生成为伪装DEM数据。非法用户无法获取真实地形数据，但是合法用户使用密码K就可以将真实的地形数据还原。该算法在隐蔽通讯领域有广阔应用前景。算法可以完全公开。     

单向板与双向板的划分依据与设计中若干问题的讨论

仍采用简单条 带法, 通过分析载荷及弯矩在长、短跨方向的分配及随跨长比的变化情况, 明确提出当按弹 性理论分析时, 宜采用长短跨长比为3作为划分单、双向板的界限. 然后从塑性铰线法设计 双向板的基本方程入手, 经分析讨论后得出当按塑性理论设计时, 单双向板的分界实质上是 相对的, 矩形板甚至正方形板究竟是单向板还是双向板, 完全取决于配筋方式这一结论. 最 后给出了双向板按单向板设计的建议.     

动态粗信息粒度矩阵的关系讨论

在前面已讨论过的静态粗信息矩阵数量特征(粒度、精度)基础上,利用动态粗糙集理论,进一步给出动态粗信息粒度矩阵的三种形式,系统地讨论了静态、动态系统的粗信息粒度矩阵的特征及其关系定理,这一研究不仅完善了粗信息矩阵这一新的研究方向内容,而且为动态系统的知识挖掘提供了一个可靠的依据。     

铁磁共振法测磁各向异性

采用铁磁共振方法,研究了铁磁/反铁磁双层膜系统中,因交换耦合以及磁晶各向异性而产生的有效各向异性场.结果表明:被测系统有无交换偏置场以及其正负号性质等均能在共振谱中得到辨析.结果还显示:沿着不同结晶方向施加外磁场,共振场的行为与磁晶各向异性以及铁磁/反铁磁交换耦合作用而诱发的单向各向异性等密切相关.将共振频率的变化看成外磁场(包括其方向和大小)的函数,研究得到了单向各向异性,立方各向异性等对共振频率的影响,并同实验结果做了很好的比较. 关键词： 铁磁/反铁磁双层膜 交换耦合 铁磁共振 单向各向异性     

高温环境下T300/BMP350拉伸力学行为研究

对不同温度下的耐高温树脂基复合材料T300/BMP350的0°和90°单向层合板进行静载拉伸实验,得到材料在不同温度下的应力-应变响应,分析了温度对材料的力学性能影响。通过高温应变片采集到材料在高温环境下的热输出和破坏时的极限应变,分析了材料的热行为。通过分析材料的应力-应变曲线和失效模式,研究了材料的损伤和失效机理。研究结果表明:T300/BMP350树脂基复合材料具有很好的耐高温性能。高温下0°方向的拉伸强度和模量保持率达到80%以上,90°方向的拉伸强度和模量保持率可以达到50%以上。高温环境对材料的极限应变影响不大,材料破坏模式均为脆性破坏。基于实验结果,对材料的强度随温度的变化进行拟合,预测了该材料在350℃时0°和90°的拉伸强度。     

Development of a surface acoustic wave wireless and passive temperature sensor incorporating reflective delay line

based on optimal design on the core element of the sensor,a wireless and passive surface acoustic wave(SAW)temperature sensor integrated with ID Tag was presented.A reflective delay line,which consists of a transducer and eight reflectors on YZ LiNbO3 substrate.Was fabricated as the sensor element,in which,three reflectors were used for temperature sensing,and the other five were for the ID Tag using phase encoding.Single phase unidirectional transducers(SPUDTs)and shorted grating were used to structure the sAW device,leading to excellent signal to noise ratio(SNR).The performance of the SAW device was simulated by the coupling of modes(COM)prior to fabrication.Using the network analyzer,the response in time domain of the fabricated 434 MHz SAW sensor was characterized,the measured S11 agrees well with the simulated one,sharp reflection peaks,high signal/noise,and low spurious noise between the reflection peaks were observed.Using the radar system based on FSCW as the reader unit.the developed SAW temperature sensors were evaluated wirelessly.Excellent1 inearity and good resolution of士1℃ were observed.     

Low threshold voltage light-emitting diode in silicon-based standard CMOS technology

Low-voltage silicon(Si)-based light-emitting diode(LED) is designed based on the former research of LED in Si-based standard complementary metal oxide semiconductor(CMOS) technology.The low-voltage LED is designed under the research of cross-finger structure LEDs and sophisticated structure enhanced LEDs for high efficiency and stable light source of monolithic chip integration.The device size of low-voltage LED is 45.85×38.4(μm),threshold voltage is 2.2 V in common condition,and temperature is 27 ℃.The external quantum efficiency is about 10-6 at stable operating state of 5 V and 177 mA.