Research progress in terahertz quantum cascade lasers

The terahertz(THz)quantum cascade laser(QCL)is a coherent THz source based on intersubband transitions of unipolar carriers.As semiconductor lasers,THz QCLs are solid-state,electrically pumped,tunable,and can be easily integrated.This paper reviews the state of the art for the design,operation temperature,and output power of THz QCLs.Their applications in THz communication and imaging are also discussed.     

“三软”地层巷道支护方式探讨

三软地层巷道的支护方式主要有架棚支护、衬砌封闭支护、可缩性U型钢支护、置换支护、锚喷网支护、锚喷多体联合支护。     

Real-time estimation of hand gestures based on manifold learning from monocular videos

Object pose estimation by manifold learning has become a hot research area recently. In this paper, we propose an efficient method that can recover pose and viewpoints for numerous hand gestures from monocular videos based on Locality Preserving Projections. We first select some hand dynamic gestures as primitive hand motions and set a 3D-2D mapping table to relate 3D joint angles of sampling static pose with their projective silhouettes from arbitrary viewpoints. Then the embedding space and explicit mapping function are learnt for every primitive motion. In order to make classification and prediction among those embedding spaces, a Subspace Filtering Algorithm is also proposed which can recognize and recover numerous hand dynamic gestures by the combination of primitive gestures. At last, by using skin color cues and oriented k-Dops, multi-hands can be labeled and tracked separately and accurately. Extensive experimental results demonstrate qualitatively and quantitatively that 3D pose recovery of hands can be achieved by our method robustly and efficiently.     

Insights into the weep performance and modeling of perforated plates

Weeping is an important hydraulic parameter for the design and optimization of perforated plates because it determines the lower limit of the tray operation (vapor load). Therefore, an accurate prediction of the weep rate is very important. First, according to our theoretical analysis of the weeping phenomena of large-scale perforated trays, we proposed three weep modes on a perforated tray: (1) random weeping in the bubbling zone, (2) dumping in the nonbubbling zone, and (3) liquid fluctuation-induced weeping. Second, a weep rate model was developed, and the literature data were correlated to determine model parameters. Results showed the fractional hole area substantially affects the model parameters. We also examined the effects of the tray structure, flow parameter, and fluid physical properties on the weep rate. Finally, the developed model was used to predict the weep rate of different scale trays reported in references, and the prediction results showed good agreements.     

基于中间件技术的制造业需求管理的设计与实现

本文通过八个制造项目抽取出制造业需求管理系统模型,并且描述了如何运用中间件技术实现制造业需求管理.本文设计出系统的功能模块和数据库表结构以及表之间的关系;根据J2EE三层架构,给出了需求管理软件实现的静态技术框架和动态技术框架.     

富硒乳酸菌的筛选及其富硒能力的初步研究

从黄水中筛选到一株富硒乳酸菌，经鉴定为布氏乳杆菌（Lactobacillus buchneri）。通过亚硒酸钠抗性筛选和MRS液体培养基发酵培养，初步确定其富硒条件为：接种量10％（v／v），亚硒酸钠添加量46μg／mL，pH6．2，37℃，培养36h，富硒能力为56．52％。     

热处理对TLM钛合金管材组织及力学性能的影响

采用规格为Ф4.0 mm×0.3 mm冷轧TLM(Ti-25Nb-3Zr-3Mo-2Sn,TLM))合金细径薄壁管材,分别在660,720℃进行固溶处理以及对720℃固溶态管材在510℃进行时效处理,利用金相显微镜、XRD、室温拉伸及断口观察分析了固溶、时效对管材组织、力学性能的影响。不同固溶态管材均为等轴组织,随着固溶温度升高,平均晶粒尺寸增大。相变点以上的固溶组织由β相和α'相组成,相变点以下固溶组织还有少量α相。时效过程中,针状的α相在晶界析出更快,合金相变化过程为β+α'→β+α'+α→β+α,时效时间大于3 h时,α相的析出使应力-应变曲线的"双屈服"特征减弱;随着时效时间的延长,抗拉强度、屈服强度及弹性模量升高,而延伸率降低。综合分析表明:720℃+510℃,3 h时效态具有较好的综合力学性能。