高速俯冲SAR多模式实时信号处理系统

针对高速俯冲SAR多模式实时信号处理系统的特殊性,提出了一种设计与实现方案.对高速俯冲SAR应用背景及工作模式进行介绍,并说明了本系统所使用的SAR成像算法.在此基础上,提出了可包容单通道多子图的扫描SAR处理和三通道单脉冲处理的系统架构设计方法,并对其中的关键技术如原始数据流方式、高效率数据共享方法、快速模式切换方法和低功耗休眠功能进行具体描述.挂飞试验的实时处理结果验证了本系统的正确性和有效性.     

CRTSⅡ型板式无砟轨道精调施工技术

随着国家高速铁路建设的快速发展,CRTSⅡ型板式无砟轨道得到了广泛应用,是直接关系到工程质量和运行寿命的关键技术。通过对现场的实践摸索和提炼,使轨道板在准备、粗铺、精调与人机结合效率方面有了显著提高,为以后的施工积累了经验。     

LPG喷雾特性的试验及数值模拟

在定容室内,采用高速摄影技术对液态LPG喷雾的宏观特性进行了研究,并与柴油进行了对比.试验结果发现,在相同喷射条件下,由于LPG较好的蒸发和雾化特性,其喷雾贯穿距离较柴油的短,喷雾锥角较柴油的小.采用KIVA3V2和KHRT破碎模型对LPG和柴油的喷雾特性进行的模拟计算结果表明,在喷雾初期贯穿距离的计算值和试验值符合较好,而在喷雾后期,由于高速摄影不能记录喷雾前端细微油粒的运动,喷雾贯穿距离的计算值和试验值之间存在一定的偏差.通过计算还发现,LPG喷雾的索特平均半径rSMR比柴油的要小;喷雾体外围液滴的rSMR比喷雾体中心的要小.     

基于模糊原理与频率分组的G函数算法

针对CHESS系统核心技术差分调频算法中G函数存在的缺点,提出一种新的G函数算法,其中频率转移函数采用了模糊算法、选择算法和复杂的分组算法.分组算法中的频率组作为调频状态量,组内再确定频率点.模糊算法和选择算法保证了转移函数的复杂度,改善了跳频序列的随机性和均匀性,增强了系统的隐蔽性和抗跟踪性.     

一种多级迭代干扰消除多用户检测算法

提出了快跳频多址通信多级迭代干扰消除多用户检测算法.该算法首先使用传统检测器对只有惟一最大行的用户做出正确译码,对于有多个最大行的用户进行迭代干扰消除.在迭代干扰消除中,对干扰数据信干功率比进行估计,若干扰频点没有受到其他信号的重叠干扰,则在迭代中被消除,否则继续迭代,直到所有用户译码完成.该算法具有线性的复杂度,消除了Fiebig多级干扰消除算法的错误传播,仿真结果表明提出的多级迭代干扰消除算法性能优于其他多用户算法.     

GPS软件接收机中C/A码信号捕获的圆周相关算法

采用圆周相关算法实现全球卫星定位系统(GPS)C/A码信号的捕获. 该算法用快速傅立叶变换将输入数据和本地产生的数据变换到频率域, 在频率域进行二者的圆周相关处理, 对相关结果反变换并找到其最大绝对值, 将该值与预先设定的门限值比较, 如果大于门限值, 则信号捕获成功. 圆周相关算法可实现快速获取GPS C/A码信号, 且灵敏度较高.     

电液比例控制技术在快速深拉伸液压机中的应用

目前快速深拉伸液压机大多采用液压开关式控制系统,它存在着响应速度低、冲击振动大及拉伸件废品率高等问题。文章在比较了3种液压控制技术性能及特点的基础上,设计了一种快速深拉伸液压机的电液比例控制系统,使压边力的变化符合了拉伸工艺要求,滑块速度转变平稳,较好地解决了上述问题。     

Mating behaviour and maternal care in the tropical savanna funnel-web spider Aglaoctenus lagotis Holmberg (Araneae: Lycosidae)

Despite their abundance and diversity, Neotropical spiders have been the subject of relatively few studies of behavioural ecology. The sexual behaviour and maternal care of the spider Aglaoctenus lagotis (Lycosidae) is described here. We performed experimental manipulations to test the hypothesis that males are attracted by female cues in the web. Two predictions were tested: (a) webs used by a virgin female will attract more males than webs used by an inseminated female; (b) the main cue in the web is chemical, so webs recently used by virgin females will attract more males than those that are not recently used. Additionally, we tested the hypothesis that maternal care increases offspring survivorship. Results showed that males are attracted by recently used webs (z = 0.0015; p = 0.037; z-test) and webs of virgin females (z = 0.041; p = 0.036, z-test). Male sexual behaviour presented three different categories: court, pre-mate and mate. After the mating, the females built a cocoon that was transported adhered to the spinnerets and held by the last pair of legs. After the hatching of the eggs, the young migrated to the dorsal region of the mother's body for 5 days. During maternal care the mother eliminates a yellowish drop from its oral cavity, which is collected by the young. During the development of the young until adulthood, the offspring that have their mother present in the first stages of life have greater survival compared with those without maternal care. Our results make it possible to perform comparative analyses between a South American Lycosidae species and other species distributed worldwide.     

应用动力学模型的高速主轴无试重动平衡方法

为解决高速主轴由于不平衡导致的振动问题,提出了一种基于动力学模型的高速主轴动平衡方法,其仅需在工作转速下采集振动响应数据,且无需停机试重.该方法通过对连续分布的不平衡量进行集中化处理,缩减不平衡响应与不平衡量之间的关系矩阵,可以在高速主轴的任意2个位置上实现双面平衡.研究结果表明,该方法能够准确地识别出等效集中的不平衡量,且所识别的由等效不平衡量引起的振动响应与原始振动响应基本一致.因此,添加配重后可使主轴各位置不平衡振动得到有效地抑制.     

基于主模型CAD/CAE集成的卷绕锭轴结构参数优化

高速卷绕头是化纤长丝纺丝机的重要单元机,国内之前研究相对较少。采用虚拟产品开发技术进行高速卷绕头新产品开发的技术创新,提高卷绕头产品开发效率。与同类研究类似,在高速卷绕头产品的虚拟开发过程中,集成CAD/CAE系统存在若干技术瓶颈。基于CAD/CAE系统集成方法的对比分析,建立了主模型CAD/CAE集成框架,并在该框架下进行了高速卷绕头锭轴结构参数优化设计,其优化设计的动力性能分析结果验证了基于主模型CAD/CAE集成框架进行高速卷绕锭轴部件虚拟开发的有效性。

Abstract：

Researches based on the high speed winder, which is a key unit machine for filaments treatment, are relatively rare in China. The techniques of virtual product development （VPD） were applied to improve the new product development of the high speed winder, which would raise the product development efficiency of the high speed winder. Similarly to the research of this kind, in the procedure of developing the virtual product for the high speed winder, there were several key technical problems in the CAD/CAE integrated system. The contrast analysis of the CAD/CAE integrated methods was given; furthermore, the CAD/CAE integrated framework based on master model was built, in which the structural parameters of the high-speed winder chuck was optimized for design. The dynamic characteristics analysis for the optimization design was done; consequently, the result indicates that in the CAD/CAE integrated framework based on master model, the structural parameter optimization of high-speed winder chuck is available.