潜艇磁场建模方法的分析与比较

对潜艇进行磁探仪探测,需了解潜艇的磁特性模型.潜艇磁性物质分布复杂,直接用解析方法求解其磁场相当困难.经过近几十年的发展,目前已经得到了多种有效的潜艇磁场建模方法.本文分析了目前潜艇磁场建模的几种方法,对各种方法的基本原理进行阐述,并对其适用范围进行分析.最后对潜艇磁场数学模型的选择进行了说明.     

水面目标合成孔径雷达图像识别系统研究

从现代战争全天时、全天候、大范围和远距离探测的需要出发,提出了水面目标SAR图像识别系统的设想,阐述了部分问题的解决方法.     

Weak correlation dictionary construction method for sparse coding

For sparse coding, the weaker the correlation of dictionary atoms is, the better the representation capacity of dictionary will be. A weak correlation dictionary construction method for sparse coding has been proposed in this paper. Firstly, a new dictionary atom initialization is proposed in which data samples with weak correlation are selected as the initial dictionary atoms in order to effectively reduce the correlation among them. Then, in the process of dictionary learning, the correlation between atoms has been measured by correlation coefficient, and strong correlation atoms have been eliminated and replaced by weak correlation atoms in order to improve the representation capacity of the dictionary. An image classification scheme has been achieved by applying the weak correlation dictionary construction method proposed in this paper. Experimental results show that, the proposed method averagely improves image classification accuracy by more than 2%, compared to sparse coding spatial pyramid matching (ScSPM) and other existing methods for image classification on the datasets of Caltech-101, Scene-15, etc.     

桥梁典型减隔震装置性能对比研究

减隔震支座的选择是减隔震设计的关键环节,然而目前研究多针对单一类型减隔震支座而没有对不同类型减隔震支座的适用性进行比较。通过对比几种桥梁典型减隔震支座的减震原理和关键力学性能,提出桥梁典型减隔震支座的适用范围。结合某一工程实例对两种典型减隔震支座的减震效果进行对比。分析结果表明,采用减隔震支座会大大降低传到结构上的地震力,但同时引起较大的震后位移。结论表明结构减隔震设计应合理选择减隔震支座,优化其力学参数,改善结构的自振周期,平衡地震力与地震位移的关系,最终实现结构的抗震设防目标。     

Operating costs in Norwegian toll companies: a panel data analysis

The objective of this paper is to ease the planning of new toll projects by providing estimates of operating costs, and to help us make better informed decisions about the design of toll collection systems. To do so we use panel data for Norwegian toll companies to estimate average cost functions. The main results can be summarised as follows. We provide evidence of very important unexploited economies of scale. The estimated cost curves are very steep for traffic levels below the sample mean, and become almost entirely flat over a wide range above the sample mean. A higher share of vehicles using on board units will significantly reduce average costs. Competitive tendering will significantly reduce average operating costs by as much as 25%. Our results also suggest that increased number of lanes, higher debt and passenger charging will increase average operating costs whereas average operating costs are lower for toll cordons compared with other projects.

基于霍尔位置传感器的永磁同步电机方波启动问题研究

针对基于霍尔位置传感器的永磁同步电机启动不稳定的情况,本文提出了永磁同步电机180°方波电流启动,高速后切换到正弦波电流方法。以STM32F103为核心主控芯片,搭建硬件系统和软件算法,实验结果表明本控制策略能够实现满载启动和加速过程,电机运行平稳。     

安全探测装置在屏蔽门系统中的应用

讨论安全探测装置设置的必要性,阐述安全探测装置的组成结构和功能,分析安全探测装置的工作原理以及电源、电气控制和通信接口设计;通过工程现场的安装及测试,完全达到预期效果,能够有效避免人身事故的发生.     

用ERA法建立计及传动系扭振的整车振动模型

运用动态子结构综合原理建立了整车振动方程，用特征系统实现（ＥＲＡ）算法辨识子结构与动力学参数，从而建立了计及车体弹性，发动机支承刚度和传动系扭振的整车振动分析模型。利用该模型可更全面，真实地分析，预测和控制整车的异常振动。分析表明，计及传动系扭振与否，对整车频率及振动特性有明显影响。     

TDI-FP法检测宫颈癌组织中人乳头瘤病毒16、18型别感染

目的通过模板介导的染料终止子掺入-荧光偏振技术(TDI-FP)检测宫颈癌组织中人乳头瘤病毒(HPV)16、18感染情况,以初步探讨本地区HPV流行特点。方法基于TDI-FP的基本原理,以HPV16、18 L1克隆重组质粒为模板,用HPV通用引物GP5+/6+PCR扩增,再通过检测探针杂交后掺入的特异荧光素标记碱基的不同来判断病毒的类型。结果在宫颈癌组织中HPV16和18型阳性率分别为61.8%及32.7%,高危型HPV占宫颈癌HPV的98.1%,宫颈癌组高危型HPV阳性率显著高于癌前病变组和慢性宫颈炎组。结论初步提示宫颈癌患者HPV感染以高危型为主,其中有超过一半的患者以HPV16型感染为主。TDI-FP是一新兴的高通量基因检测技术,快速、可靠、敏感、特异并且操作简便,更适合于大规模临床筛查及在临床上广泛推广应用。     

成年大鼠液压冲击脑损伤诱导室下区Nestin和GFAP的表达

目的　应用免疫组织化学和免疫荧光双标技术结合激光共聚焦显微镜 ,观察脑损伤后不同时期室下区巢蛋白(Nestin)和胶质酸性纤维蛋白 (GFAP)的表达及其细胞类型。方法　用动液压冲击法建立动物模型 ,用LeicaQ5 0 0IW图像处理系统及免疫组化和免疫荧光双标法分析和显示不同时期 (1、3、5d ,1、2、3、4、6、8周 )Nestin和GFAP的表达变化。结果　损伤 2 4h后 ,室下区有大量Nestin和GFAP的表达 ,且激光共聚焦显微镜观察到有Nestin阳性突起与GFAP共存现象 ,7d左右达到高峰 ,然后随着时间的推移其表达逐渐下降。正常组和假手术组 ,室下区也可见到Nestin和GFAP的表达 ,但与脑损伤组相比较低 (P <0 .0 5 )。结论　脑损伤可诱导室下区Nestin和GFAP的表达 ,Nestin阳性突起与GFAP共存细胞可能具有干细胞特性 ,与神经元的修复有关。