基于有限内存Broyden-Fletcher-Goldfarb-Shanno优化算法的图像非刚性配准方法

图像配准可以分为刚性配准和非刚性配准两类,图像非刚性配准是图像处理研究的热点和难点,其中的参数模型往往转化为无约束优化问题的求解,当参数数目较大时求解比较费时,提高此类算法效率的关键之一是减少迭代算法中矩阵的计算量和存储量.本文研究了一种非刚性配准方法,该方法应用Basic样条自由变形模型,此模型改变控制点只影响其附近...     

三跨与单跨护栏系统的抗冲击性能比较

为了解波形梁护栏系统的冲击响应及各跨之间的相互作用对护栏系统变形和受力的影响,设计和实施了半刚性三跨缩比护栏系统冲击试验,各试件尺寸与实际尺寸的缩比比例为1 ：3．75,对三跨护栏系统与单跨护栏系统的变形、冲击力、速度、能量吸收等特性进行了比较,计算各部件对护栏系统能量吸收的贡献。结果表明：三跨护栏系统吸收了较多的能量,整体的能量吸收更加均匀、合理、试验方法和所得结论为进一步开展工程护栏的优化设计奠定了基础。     

单片机控制的光电测速仪

提出了一个用８０３１单片机和光电编码器组成的转速与转角测试方案,介绍其实现的基本原理和结构特点,给出了接口电路和软件设计方法。由于采用了单片机和光电传感器,该系统具有硬件电路简单、测量精度高、性能稳定可靠等优点,其适用于自动控制、自动检测及各种转速与方位角的测量与控制等领域。     

平纹编织复合材料层板维修的挖补角度优化分析与试验验证

鉴于平纹编织复合材料的广泛应用与该类型层板维修研究的缺失性,研究针对一系列不同修补角度的平纹编织复合材料层板维修工况,进行了三维有限元模型分析计算与试验验证,得到结论如下:修补角度的选取对于恢复强度的影响极为明显。研究使用的平纹编织复合材料层板结构最佳修补角度为4°,最大强度修复率达到了66.98%;分析采用的三维有限元修补模型得到的强度计算值与试验数据基本吻合,说明该计算模型能够满足维修设计的需求,为实际修理提供较好的维修指导。     

基于图像信息处理的车辆自动驾驶控制方法

在分析驾驶员利用图像信息进行驾驶的一般规律基础上,提出了利用图像信息处理技术实现车辆路迹追踪自动行驶的控制方法和规则,并进行了模拟计算和试验．结果表明,所提出的控制方法和规则用于进行车辆的自动驾驶是可行的．     

树木元素富集与树种及土壤类型关系的初步研究

用富集系数研究了相同土壤类型上生长的不同树种,不同土壤类型上生长的同一树种,及不同土壤类型上生长的不同树种对１８种元素的富集情况．结果表明,黄棕壤上生长的悬铃木对元素Ｐ的富集系数最大,而马尾松对元素Ｃｄ的富集系数最大;对于生长在不同土壤类型上的马尾松,则由于土壤本身偏酸性而造成黄棕壤和红壤上生长的马尾松对大部分元素有较高的富集系数;从不同土壤类型上生长的不同树种对元素的富集系数来看,元素Ｐ的差异最大,红壤、黄棕壤上生长的马尾松对元素Ｃｄ的富集系数远远大于其它土壤类型上生长的各树种（本文所讨论范围内）,过渡元素及原子序数较大的Ｂａ、Ｐｂ两个元素的富集系数则无明显差异     

RNA interference-mediated inhibition of Hepatitis B Virus replication

Persistent and recurrent infection of hepatitis B virus (HBV) represents one of the most common and severe viral infections of humans, and has caused a formidable health problem in the affected countries. Currently used antiviral drugs have a very limited success on controlling HBV replication and infection. RNA interference (RNAi), a process by which double-stranded RNA (dsRNA) directs sequence-specific degradation of target mRNA in mammalian and plant cells, has recently been used to knockdown gene expression in various species. In this study, we sought to determine whether RNAi-mediated silencing of HBV viral gene expression could lead to the effective inhibition of HBV replication. We first developed RNAi vectors that expressed small interfering RNA (siRNA) and targeted the HBV core or surface gene sequence. Our results demonstrated that these specific siRNAs efficiently reduced the levels of corresponding viral RNAs and proteins, and thus suppressed viral replication. Treatment with siRNA gave the greatest reduction in the levels of HBsAg (92%) and in HBeAg (85%) respectively in the cultured cell medium. Our findings further demonstrated that the RNAi-mediated antiviral effect was sequence-specific and dose-dependent. Therefore, our findings strongly suggest that RNAi-mediated silencing of HBV viral genes could effectively inhibit the replication of HBV, hence RNAi-based strategy should be further explored as a more efficacious antiviral therapy of HBV infection.     

A photovoltaic device structure based on internal electron emission

There has been an active search for cost-effective photovoltaic devices since the development of the first solar cells in the 1950s (refs 1-3). In conventional solid-state solar cells, electron-hole pairs are created by light absorption in a semiconductor, with charge separation and collection accomplished under the influence of electric fields within the semiconductor. Here we report a multilayer photovoltaic device structure in which photon absorption instead occurs in photoreceptors deposited on the surface of an ultrathin metal-semiconductor junction Schottky diode. Photoexcited electrons are transferred to the metal and travel ballistically to--and over--the Schottky barrier, so providing the photocurrent output. Low-energy (approximately 1 eV) electrons have surprisingly long ballistic path lengths in noble metals, allowing a large fraction of the electrons to be collected. Unlike conventional cells, the semiconductor in this device serves only for majority charge transport and separation. Devices fabricated using a fluorescein photoreceptor on an Au/TiO2/Ti multilayer structure had typical open-circuit photovoltages of 600-800 mV and short-circuit photocurrents of 10-18 micro A cm(-2) under 100 mW cm(-2) visible band illumination: the internal quantum efficiency (electrons measured per photon absorbed) was 10 per cent. This alternative approach to photovoltaic energy conversion might provide the basis for durable low-cost solar cells using a variety of materials.     

多台系统异步可靠性增长模型及其统计分析

在各单台系统Weibull过程的可靠性增长假设条件下,建立了一种多台系统异步可靠性增长模型,并给出了可靠性增长试验数据的统计分析方法,包括模型参数的点估计、区间估计、系统MTBF估计、增长趋势检验及模型拟合优度检验等.较好地解决了不同步可靠性增长试验数据的统计分析问题.     

曲线坐标系下哈密顿体系的建立

在任意曲线坐标系下建立了曲六面体区域的哈密顿体系，扩大了哈密顿体系的适用范围，并使系统方程具备了处理任意复杂边界条件的能力。