PSD对称性检测在车牌和人脸识别中的应用探索

车牌和人脸识别是实现现代智能化的重要步骤,对车牌和人脸的识别具有重要的意义。对称性是车牌和人脸的重要特征,本文针对PSD对称性检测算法提取的对称性特征,探索了这些特征对车牌和人脸识别的重要作用。     

一款800V VDMOS终端结构的设计

设计了一款800 V VDMOS终端结构,采用场限环(FLR)与场板(FP)相结合的方式,在场限环上添加多晶硅场板与金属场板,有效地降低了表面电场峰值。通过调整终端结构,在135μm的有效终端长度上实现了848 V的击穿电压,最大表面电场为2.34×105 V/cm,小于工业界判断器件击穿场强标准(2.5×105 V/cm),且电场分布比较均匀,终端结构的稳定性和可靠性高。     

HSV空间和形态学处理相结合的车牌定位方法

车牌定位是实现车牌自动识别的前提.在传统的基于RGB彩色空间的形态学定位方法的基础上进行改进,提出了一种HSV彩色空间和图像形态学处理相结合的车牌定位方法.在HSV彩色空间中将车牌图像分割为H,S,V这3个单通道灰度图像,分别进行去噪和二值化处理,然后将这3幅二值图像做“与”运算得到一幅能有效去除背景干扰的二值图像,再运用形态学的闭运算和开运算进行处理,得到车牌候选区域,最后利用车牌宽高比属性进行验证以确定真实的车牌位置.实验结果表明,该方法相对传统方法实现简单,车牌定位准确、高效.     

一种基于TRIAC调光LED驱动中的相角测量技术

基于TRIAC调光,提出了一种用于LED驱动芯片中,测量经TRIAC调光器斩波后AC线电压导通角的技术,并给出了其具体电路实现方式.此方法具有测量精度可调、负载LED亮度范围可调等诸多优点,能够很好地满足实际应用的需求.基于0.5 μm BCD工艺,用Hspice进行仿真,结果表明:本文提出的相角测量技术能准确测量AC线电压导通角的大小,从而精确控制流过负载LED的电流.     

Long‐time behavior of a nonlinear viscoelastic beam equation with past history

This paper is concerned with the existence of a global attractor for the nonlinear viscoelastic beam equation with past history memory where g(u_t) is a damping like | u_t | ^ru_t and f(u) is a source term like | u | ^αu ? | u | ^βu, by considering 0 ≤ β < α and r > 0. Copyright © 2014 John Wiley & Sons, Ltd.     

Thermal radiation impact on magneto-hydrodynamic heat transfer micropolar fluid flow over a vertical moving porous plate: A finite difference approach

For this research, an examination on the magnetohydrodynamic flow of a micropolar fluid across a moving vertical porous plate for the presence of thermal radiation is achieved. It is necessary to translate the partial differential equations regulating the flow, heat, & mass transfer into dimensionless form employing proper non-dimensional variables, which are then cracked numerically by utilizing the Finite difference approach. Graphs are used to represent numerical values of various flow profiles; however, tables are used to represent the simulated values of rate coefficients. The velocity rises when the value of Grashof number, dimensionless viscosity ratio is raised, and the opposite effect is seen when the value of magnetic parameter, micro-gyration factor is raised. The result in skin friction coefficient improves when the values of magnetic parameter, micro-gyration factor, Prandtl number, and radiation are raised higher.     

Sonocatalytic injury of cancer cells attached on the surface of a nickel–titanium dioxide alloy plate

The present study demonstrates ultrasound-induced cell injury using a nickel–titanium dioxide (Ni–TiO₂) alloy plate as a sonocatalyst and a cell culture surface. Ultrasound irradiation of cell-free Ni–TiO₂ alloy plates with 1 MHz ultrasound at 0.5 W/cm² for 30 s led to an increased generation of hydroxyl (OH) radicals compared to nickel–titanium (Ni–Ti) control alloy plates with and without ultrasound irradiation. When human breast cancer cells (MCF-7 cells) cultured on the Ni–TiO₂ alloy plates were irradiated with 1 MHz ultrasound at 0.5 W/cm² for 30 s and then incubated for 48 h, cell density on the alloy plate was reduced to approximately 50% of the controls on the Ni–Ti alloy plates with and without ultrasound irradiation. These results indicate the injury of MCF-7 cells following sonocatalytic OH radical generation by Ni–TiO₂. Further experiments demonstrated cell shrinkage and chromatin condensation after ultrasound irradiation of MCF-7 cells attached on the Ni–TiO₂ alloy plates, indicating induction of apoptosis.     

In situ X‐ray data collection and structure phasing of protein crystals at Structural Biology Center 19‐ID

A prototype of a 96‐well plate scanner for in situ data collection has been developed at the Structural Biology Center (SBC) beamline 19‐ID, located at the Advanced Photon Source, USA. The applicability of this instrument for protein crystal diffraction screening and data collection at ambient temperature has been demonstrated. Several different protein crystals, including selenium‐labeled, were used for data collection and successful SAD phasing. Without the common procedure of crystal handling and subsequent cryo‐cooling for data collection at T = 100 K, crystals in a crystallization buffer show remarkably low mosaicity (<0.1°) until deterioration by radiation damage occurs. Data presented here show that cryo‐cooling can cause some unexpected structural changes. Based on the results of this study, the integration of the plate scanner into the 19‐ID end‐station with automated controls is being prepared. With improvement of hardware and software, in situ data collection will become available for the SBC user program including remote access.     

高超声速平板边界层流动显示的试验研究

本文在高超声速脉冲式风洞内对基于纳米示踪的平面激光散射技术(nano-based planar laser scattering, NPLS)的应用进行了探索, 并在此基础上对平板边界层流动结构的精细测量进行了研究. 试验来流Ma=7.3, 总压4.8 MPa, 总温680 K. 通过时序的分析和调试, 对各分系统实现了高精度的同步控制; 定量的粒子注入及混合, 实现了粒子的均匀撒播, 对主流获得了均匀的显示效果; 对于边界层流动, 获得了精细的瞬态流动结构图像, 显示了层流到湍流的转捩过程, 并分析了其时空演化特性.     

Conservative numerical methods for the Full von Kármán plate equations

This article is concerned with the numerical solution of the full dynamical von Kármán plate equations for geometrically nonlinear (large‐amplitude) vibration in the simple case of a rectangular plate under periodic boundary conditions. This system is composed of three equations describing the time evolution of the transverse displacement field, as well as the two longitudinal displacements. Particular emphasis is put on developing a family of numerical schemes which, when losses are absent, are exactly energy conserving. The methodology thus extends previous work on the simple von Kármán system, for which longitudinal inertia effects are neglected, resulting in a set of two equations for the transverse displacement and an Airy stress function. Both the semidiscrete (in time) and fully discrete schemes are developed. From the numerical energy conservation property, it is possible to arrive at sufficient conditions for numerical stability, under strongly nonlinear conditions. Simulation results are presented, illustrating various features of plate vibration at high amplitudes, as well as the numerical energy conservation property, using both simple finite difference as well as Fourier spectral discretizations. © 2015 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 31: 1948–1970, 2015