高效FTP搜索引擎的设计与实现

为了解决传统FTP搜索引擎对检索结果优化程度不够而造成的检索质量低的问题,在对FTP用户查询日志进行统计分析的基础上,采用双字节倒排索引、检索结果自动分类以及查询自动纠错等技术设计了一种高性能的智能化FTP搜索引擎.双字节倒排是对文件名中每两个字节建立倒排索引表,自动分类是对检索结果按主题划分为层次结构,查询自动纠错是以用户查询日志中的高频查询词为数据源构建拼写错误词典.试验结果表明,该方案能够有效地提高FTP搜索引擎的文件检索效率与质量.     

水泥工业生态产业链构建的理论研究与实证分析

水泥工业是典型的资源消耗型产业,同时具有消纳自身和其他行业废弃物的巨大潜力.在分析水泥生产特点的基础上,探讨了水泥工业构建生态产业链的可拓展性,并对其生态产业链进行了设计,旨在为水泥工业的建设和发展提供参考.     

基于Wilson-θ法的动荷载识别

在Wilson-θ法求解运动平衡方程的基础上,推导了时域内动荷载识别基本公式,并通过算例说明了方法的正确性.算例表明,该方法具有较高的识别精度,并具有一定的抗噪声能力,为动荷载识别提供了一种新的思路.     

防崩裂皮环在高强混凝土抗压强度实验中的应用

为防止高强混凝土在抗压强度试验中的崩射伤害作用,在实验的基础上,发明了防崩皮环,从而避免了高强混凝土在试验时向外崩射现象的发生,对实验人员的操作安全,起到了较好的防护作用．     

一次同余式组的两种求解方法

运用矩阵的初等变换法和不定方程求解法,给出了求解同余式组的两种简便方法.     

基于Petri网的语义Web服务过程模型匹配算法研究

为了在服务发现中提高效率及准确率,在服务匹配过程中引入了服务执行状态的变迁等因素即服务的过程模型。而Petri网能够把Web服务的过程模型进行形式化描述．在服务发现中引入Petri网,通过Petri网描述web服务的过程模型,再对Petri网进行语义标注,最后通过计算过程模型的相似度来实现基于Petri网的语义Web服务发现匹配．这种方法结合现有采用功能性参数匹配的语义web服务发现对提高服务发现率,尤其对改善服务发现准确率起到了一定的作用．     

煤矿区煤尘污染遥感监测研究

在相关研究的基础上,提出了基于SPOT5图像提取煤尘污染的技术方法,并进行了实例研究．研究表明,该煤尘污染监测技术可行、操作性强,对于煤矿区煤尘污染监测具有重要意义．     

样品厚度误差对THz波段样品折射率的影响

本文用THz时域光谱技术对不同厚度的同种维生素进行了探测,并得到了它们在0.2-2.5 THz波段范围的折射率谱.通过对比实验结果发现：厚度不同的同种样品在相同的频率下具有不同的折射率;样品越厚,折射率的误差就越小.这一实验结果与理论推导相一致.本文的研究结果可以作为利用THz时域光谱技术依据折射率鉴别物质的参考因素.     

Effect of B2O3 on the aqueous tape casting and microwave properties of Li2O–Nb2O5–TiO2 ceramics

The effect of B2O3 addition on the aqueous tape casting, sintering, microstructure and microwave dielectric properties of Li2O-Nb2O5-TiO2 ceramics has been investigated. The tape casting slurries exhibit a typical shear-thinning behavior without thixotropy, but the addition of B2O3 increases the viscosity of the slurries significantly. It was found that doping of B2O3 can decrease the tensile strength, strain to failure and density of the green tapes. The sintering temperature could be lowed down to 900℃ with the addition of 2 wt% B2O3 due to the liquid phase effect. No secondary phase is observed. The addition of B2O3 does not induce much degradation on the microwave dielectric properties. Optimum microwave dielectric properties of εr 67, Q×f 6560 GHz are obtained for Li2O-Nb2O5-TiO2 ceramics containing 2 wt% B2O3 sintered at 900 1C. It represents that the ceramics could be promising for multilayer low-temperature co-fired ceramics (LTCC) application.     

Construction and expression of retroviruses encoding dual drug resistance genes in human umbilical cord blood CD34+ cells

A series of retro viral vectors encoding humanmdr1 gene alone as wetl as in combination with either humanmgmt gene or human mutantSer ³¹-dhfr gene are engineered. The resultant retroviruses are used to transduce human umbilical cord blood CD34⁺ cetls. It has been shown that expression of dual drug resistance genes in transduced cetls confers a broad range of resistance to both kinds of corresponding drugs. These data suggest a rationale for the use of such double chemoresistance gene constructs in anin vivo model in which transduced hematopoietic cetls will acquire multiple protection against the cytotoxic side effects of combination chemotherapy and may have future application in chemoprotection of normal tissues, thus killing tumor cetls more effectivety.