Nanofabrication of 1-D photonic bandgap structures along a photonic wire

A strongly-guided one-dimensional (1-D) waveguide called a photonic wire has high spontaneous emission coupling efficiency, enabling one to realize low-threshold lasers. Combined with the use of 1-D photonic bandgap structures consisting of arrays of holes etched within the photonic wire, novel microcavity lasers can be realized. We report the nanofabrication of a photonic bandgap structure for 1.5 /spl mu/m wavelength along a InGaAsP photonic wire, and discuss numerical simulations for its electrodynamics.     

Directional light output from photonic-wire microcavity semiconductor lasers

We have obtained directional light output from a recently realized InGaAsP photonic-wire microcavity ring lasers. The output was achieved by fabricating a 0.45-/spl mu/m-wide U-shape waveguide next to a 10-/spl mu/m diameter microcavity ring laser. The laser has a threshold pump power of around 124 /spl mu/W when optically pumped at 514 nm. It is comparable to the former structure without output coupling. The output coupling efficiency can be controlled carefully by choosing the spacing between the laser cavity and the waveguide.     

T6114天然气发动机的使用和维护

简要阐明了T6114天然气发动机使用过程中的注意事项,如CNG气质、机油及冷却液的选用,发动机的正确操作等,重点介绍电控燃气系统的维护保养及故障诊断,特别是如何检查与清除系统故障码。     

连杆形状优化设计的灵敏度分析

首先讨论了结构形状灵敏度分析的边界元摄动法，然后对柴油机连杆进行了灵敏度分析，得到了一些重要结论，为改进连杆设计提供了依据。     

Red photoluminescence BCNO synthesized from graphene oxide nanosheets

In this paper, we demonstrate the conversion of graphene oxide (GO) into boron carbon oxynitride (BCNO) hybrid nanosheets via a reaction with boric acid and urea, during which the boron and nitrogen atoms are incorporated into graphene nanosheets. The experimental results reveal that GO is important for the photoluminescence (PL) BCNO phosphor particles. More importantly, in this system, the prepared BCNO phosphors can be used to prepare the materials needed for red light emitting diodes (LEDs).     

太阳能级Si片清洗工艺分析

在实验基础上对太阳能级Si片碱性清洗工艺进行了分析,指出碱性清洗液在适宜的工艺环境下,配合超声清洗和表面活性剂的使用可以获得良好的清洗效果。结果表明,表面金属浓度分别达到Cu元素小于1.3×10~(14)atoms/cm~2,Fe元素小于5×10~(13)atoms/cm~2。碱性清洗液与Si晶体发生两步化学反应,平衡后OH~-离子浓度保持稳定,是以获得稳定的清洗效果同时提高清洗液的使用效率。     

Unsupervised Learning for Solving RSS Hardware Variance Problem in WiFi Localization

Hardware variance can significantly degrade the positional accuracy of RSS-based WiFi localization systems. Although manual adjustment can reduce positional error, this solution is not scalable as the number of new WiFi devices increases. We propose an unsupervised learning method to automatically solve the hardware variance problem in WiFi localization. This method was designed and implemented in a working WiFi positioning system and evaluated using different WiFi devices with diverse RSS signal patterns. Experimental results demonstrate that the proposed learning method improves positional accuracy within 100 s of learning time.     

Investigation of charge loss characteristics of HfO2 annealed in N2 or 02 ambient

The retention characteristics of electrons and holes in hafnium oxide with post-deposition annealing in a N2 or 02 ambient were investigated by Kelvin probe force microscopy. The KFM results show that compared with the N2 PDA process, the O2 PDA process can lead to a significant retention improvement. Vertical charge leakage and lateral charge spreading both played an important role in the charge loss mechanisms. The retention improvement is attributed to the deeper trap energy. For electrons, the trap energy of the HOS structure annealed in a N2 or 02 ambient were determined to be about 0.44 and 0.49 eV, respectively. For holes, these are about 0.34 and 0.36 eV, respectively. Finally, the electrical characteristics of the memory devices are demonstrated from the experiment, which agreed with our characterization results. The qualitative and quantitative determination of the charge retention properties, the possible charge decay mechanism and trap energy reported in this work can be very useful for the characterization of hafnium charge storage devices.     

相移迁移法在激光超声合成孔径聚焦技术中的应用

通过分析脉冲源激光辐照于工件表面激发的多模式、宽带超声体波信号并结合合成孔径聚焦技术(SAFT),实现了对工件内部微小缺陷的检测、定位和成像。首先基于有限元仿真模拟了激光激发超声波在含缺陷样品中的传播过程,编写了基于相移迁移法(PSM)的SAFT成像算法,然后在实验中使用激光在含缺陷样品表面激发超声波,使用激光测振仪探测超声波,并基于已有算法和探测结果对样品内缺陷进行了检测和定位,以验证算法的正确性。有限元仿真以及实验结果均表明,将激光超声技术与频域SAFT-PSM结合,能够有效地对微小缺陷进行检测和定位,且其图像重构速度快于时域SAFT,可为激光超声无损检测提供更快速的实时技术方案。     

基于改进的ResNet手指静脉识别

针对指静脉提取困难和识别精度不够高等问题,提出了一种基于ResNet改进的手指静脉识别方法.首先,使用深度超参数化卷积(DO-Cony)代替网络中的传统卷积,在减少模型参数的同时提高了网络识别率.然后,将空间注意力模型(SAM)和挤压激励块(SE-Block)融合,应用于改进的残差网络(ResNet)提取图像在通道和空...