一种组稀疏信道估计中的信号重构优化方法

针对正交频分复用(OFDM)系统信道的稀疏性,同时考虑信道的时间选择性和频率选择性,运用压缩感知理论研究了基于组稀疏压缩感知(GSCS)的时变信道估计方法。该方法通过信道系数和基扩展系数的稀疏表示,提出了组稀疏概念以测量、重构信号。在GSCS信号重构过程中,提出了一种新的优化方法,引入一个纠正过程,剔除错误的原子,提高了组稀疏估计方法的信号重构性能。分别在单天线和多天线系统中进行仿真实验,结果验证了本文方法的优越性。     

鸡源致病性大肠杆菌的分离鉴定及药敏试验

为了解鸡源致病性大肠杆菌的生物学特性和耐药性,试验通过采集病料、细菌分离培养、16S rRNA基因鉴定、致病性试验、药敏试验等方法。结果表明:分离出的20株细菌的培养特征、镜检特征均符合大肠杆菌特征;16S rRNA基因序列经BLAST比对与大肠杆菌同源性达99.9%～100%,确定20株分离菌为鸡源大肠杆菌;20株大肠杆菌的致病力为40%～100%;10株鸡源致病性大肠杆菌对15种抗菌药物均呈现多重耐药,耐药率为33.3%～93.3%,耐药情况较严重和复杂。     

基于知识管理的知识服务探析

探讨了知识管理与图书馆知识服务的内在联系,提出了图书馆开展基于知识管理的知识服务的对策。     

纺织基人工血管的水渗透性

选用丝素和涤纶(PET)材料,分别制备了平纹和斜纹人工血管,测试并分析了在16kPa条件下,材料性质、组织结构、水浸润时间对人工血管水渗透性的影响.结果表明,在16kPa压强下,连续测量60min,无浸润丝素平纹人工血管的水渗透性呈现先快速下降而后平稳的变化趋势,而无浸润涤纶平纹人工血管的水渗透性变化不明显;两种斜纹人工血管的水渗透性远远高于平纹组织;随着浸润时间的延长,丝素平纹人工血管首分钟水渗透量显著降低,而涤纶平纹人工血管变化不明显.     

Promoted Cytocompatibility of Silk Fibroin Fiber Vascular Graft through Chemical Grafting with Bioactive Molecules

Natural silk from Bombyx mori has been used as medical sutures for several decades,and regenerated silk fibroin( RSF)based biomaterials have been increasingly studied in the past thirty years. However,vascular graft derived from silk fibroin fiber has been explored in recent several years with development of textile science and engineering. Moreover,endothelialization of vascular graft has been seen as an ideal strategy for preventing thrombosis and getting higher patency in a long term. Therefore,in the present work silk fibroin fiber vascular graft( SF) was chemically grafted with bioactive molecules such as heparin and RSF to improve the cytocompatibility. 3-aminopropyl-triethoxysilane(APTES),1-ethyl-3-(3-dimethylaminopropyl) carbodiie hydrochlide( EDC · HCl),and N-hydroxysuccinimide( NHS) have been employed as coupling agent and crosslinking agents,respectively. Microscopy and ATRFTIR were used to characterize the surface changes and the structure of the grafts after treatment,respectively. Cell culture in vitro and MTT assay were conducted to determine the improvement of cell affinity to the graft. Furthermore,mechanical properties of the grafts before and after treatment were compared. The results showed that the chemical grafting was an effective method for improving the cytocompatibility of SF without significant loss of mechanical properties.     

深亚微米工艺EEPROM单元加固设计及辐照性能

当普通EEPROM单元在太空中应用时,会受到辐照效应的影响,导致单元可靠性降低,寿命缩短,为此,基于0.18 μm工艺,设计出一种新型抗辐照EEPROM单元.新单元采用环形栅和场区隔离管加固结构.加固后,单元面积为9.56 μm2,抗总剂量效应能力大于1 500 Gy,抗辐照能力明显优于普通结构.为明确失效机制,基于新...     

浅谈网络电子期刊的利用

介绍了网络电子期刊的定义和特点,论述了网络电子期刊的获取途径,探讨了网络电子期刊对图书馆等信息服务机构的影响。     

关于高校师资队伍建设的几点思考

本文根据高校教育系统师资队伍建设现状,从队伍建设改革的需要出发、从教师成长过程出发,浅析如何重新规划对高校教师的人员选择,以及如何对高校师资人员进行管理。     

K1,n—free图的（a,b）—因子

一个图称为Ｋ１，ｎ－ｆｒｅｅ图如何它不含Ｋ１，ｎ作为其导出子图，文中讨论了Ｋ１，ｎ－ｆｒｅｅ图有（ａ，ｂ）－因子有一些充分条件。     

以体验式旅游促进民族地区旅游商品可持发展——以凉山彝族自治州为例

目前民族地区旅游商品的开发及销售状况不尽人意,因此寻找一种积极有效的旅游方式,对于挖掘地方和民族文化内涵,加强旅游商品深度开发以及促进旅游商品的可持续发展等方面都具有极其重要的意义.本文就此进行了详细分析与论述.