酵母菌最适生长条件和自溶条件研究

采用正交实验设计,研究了酿酒酵母和扣囊拟内孢霉混合培养的最适条件和菌体的自溶作 用,得到了最佳的条件组合.实验结果表明,酿酒酵母和扣囊拟内孢霉混合培养的最适条件为: 1.5％豆饼,2％玉米粉,28℃,pH 5.0,0.2％酵母膏;酿酒酵母和扣囊拟内孢霉混合菌体的自溶条 件为:pH 5.0醋酸-醋酸钠缓冲液,55℃,0.5％NaCl.     

基于信息熵识别油气层和水层的聚类方法

简要地介绍了不确定性、信息熵、联合熵、条件熵、互信息的基本概念。将地层含有某种流体属性(如油层)的特征参数的概率分布应用于联合熵中,提出其概率分布是特征参数X与流体的特征参数Y的距离函数,再用熵与条件熵之差计算得到的互信息去识别地层的流体属性,即提出了基于信息熵识别油气层和水层的聚类方法。利用实际测井资料提取了油气层和水层的特征参数,并利用聚类方法识别出油气层和水层。识别结果与试油结论相符。该聚类方法不仅可用于识别油气层和水层,还可推广应用于划分地层岩性等领域。     

Testing and Evaluation for Web Usability Based on Extended Markov Chain Model

As the increasing popularity and complexity of Web applications and the emergence of their new characteristics. the testing and maintenance of large, complex Web applications are becoming more complex and difficult. Web applications generally contain lots of pages and are used by enormous users. Statistical testing is an effective way of ensuring their quality. Web usage can be accurately described by Markov chain which has been proved to be an ideal model for software statistical testing. The results of unit testing can b eutilized in the latter stages, wbich is an important strategy for bottom-to-top integration testing, and the other improvement of extended Markov chain model (FMM) is to present the error type vector which is treated as a part of page node. This paper also proposes the algorithm for generating test cases of usage paths. Finally, optional usage reliability evaluation methods and an incremental usability regression testing model for testing and evaluation are presented.     

Ionospheric eclipse factor method (IEFM) for determining the ionospheric delay using GPS data

By establishing the ionospheric eclipse factor (IEF) λ of the ionospheric pierce point (IPP) and its ionospheric influence factor (IFF) λ, and combining λ, λ with t of IPP, a new method of modeling high-precision ionospheric delay using GPS data-ionospheric eclipse factor method (IEFM)-is presented in this paper. The IEFM can effectively select the proper ionospheric models to model the total electron content (TEC) with different changes corresponding to annual, seasonal and diurnal variations. Initial experimental results show that the correction precision of ionospheric delay modeled by the IEFM seems to be close to that of using L3 GPS observations to directly correct the corresponding ionospheric delay.     

钢管混凝土拱极限承载力计算及相关参数分析

采用考虑材料非线性的钢管混凝土拱极限承载力计算方法,对两个模型拱进行了极限承载力计算及相关参数分析.在该方法中,对钢管混凝土拱结构采用纤维单元模型,该模型假定钢管与混凝土完全粘接,钢管对核心混凝土的套箍作用体现在以一维形式表达的核心混凝土的应力-应变关系曲线之中.针对材料非线性分析中单元内各点刚度参差不齐的特点,采用单元内设小元的方法(相当于子结构),编制了非线性有限元程序.在该程序中,计算模型完全是基于小元层次进行的,比如:单元刚度矩阵由小元刚度矩阵凝聚而成,单元节点的残余力由小元节点的残余力构成,故只需改变单元内小元个数这一个参数,就可实现对结构的重新划分,极大地降低了非线性方程组的阶数,且方便实用.在程序计算结果得到模型试验结果验证的基础上,还分析了套箍系数、截面含筋率及混凝土强度对结构极限承载力的影响.     

The Intelligent Decision Support System Model of SARS

Based on the intelligent decision support system, a new method was presented to defense the catastrophic infectious disease such as SARS, Bird Flu, etc.. By using All Set theory, the decision support system (DSS) model can be built to analyze the noise information and forecast the trend of the catastrophe then to give the method or policy to defend the disease. The model system is composed of four subsystems: the noise analysis subsystem, forecast and simulation subsystem, diagnosis subsystem and second recovery subsystem. They are discussed briefly in this paper. This model can be used not only for SARS but also for other paroxysmal accidences.     

Research ＆ Development of Grade X70 LSAW Steel Pipes for West-East Gas Pipeline

In this article the research and development of X70 large diameter longitudinal seam submerged arc welded (LSAW) steel pipes for West-East Gas Transportation Pipeline project (WEGTP) in China are introduced, including the key technique, fabrication of pipe production line, mass production and the latest progress of LSAW steel pipe technique.     

CIMS环境下SD-PDM系统设计

根据对企业生产和需求的调研,基于现代集成制造系统应用集成平台环境,设计并建立了沈阳电机股份有限公司产品数据管理(SD PDM)系统·确定了SD PDM的功能需求,主要包括项目管理、任务管理、过程管理及产品结构和配置管理·建立了由应用层、数据库层、网络层和系统层组成的4层开放式体系结构,进行了系统的功能设计,给出了SD PDM系统的操作流程·最后分析了系统技术平台选择、编码规则设计和用户权限限制等几点关键技术·SD PDM系统已在企业投入使用,提高了企业管理水平,缩短了制造和供货周期·     

基于银薄膜/荷叶SERS效应直接检测婴儿配方奶粉中三聚氰胺

以天然荷叶为衬底,结合真空磁控溅射法沉积银薄膜,制备出了一种高效的表面增强拉曼散射(SERS)活性基底.研究发现银/荷叶基底对婴儿配方奶粉中掺杂的三聚氰胺(MA)表现出良好的识别能力,而不需作额外的样品预处理.对掺杂不同浓度三聚氰胺的奶粉溶液进行定量分析,在5~50 mg/L质量浓度范围内获得了较好的线性关系(线性相关系数R20.99).根据3σ准则,检测极限估计为1 mg/L.此外,银/荷叶基底具有良好的均匀性和重复性(相对标准偏差为7.64%和10.54%).该方法对婴儿配方奶粉中三聚氰胺的检测具有简单快速、成本低且无损等优点.     

新的f(R)黑洞

f（R）引力是一个直接拓展广义相对论的修正引力理论,它的拉格朗日量是一个仅含曲率标量R的任意函数f（R）.在F（r）=1+αr的条件下（F（r）≡（df（R（r）））/（dr）和αr是一个对广义相对论小的修正量）,导出了度规f（R）引力理论中场方程的精确球对称真空解.此外,考虑了这个黑洞背景时空中的标量场扰动.用六阶WKB （Wentzel-Kramers-Brillouin）方法,讨论了拟正则模和这个黑洞的参数之间的关系,得出这个黑洞是稳定的结论.