"三个代表"重要思想的一脉相承性和与时俱进性

“三个代表”重要思想同马克思列宁主义、毛泽东思想和邓小平理论是一脉相承而又与时俱进的科学体系,一脉相承,体现在世界观和方法论、科学社会主义学说上,与时俱进,体现在进一步回答什么是社会主义、怎样建设社会主义和创造性地回答了建设什么样的党、怎样建设党的问题上。     

层次分析法在分析FDI影响因素中的应用

为降低对外投资的风险,投资者要对投资环境进行客观、全面的评价。对外直接投资环境的评估方法有很多,但层次分析法是一种定性分析与定量分析相结合的多目标决策方法。应用层次分析法分析影响FDI的因素,充分利用投资专家的个人经验和定量分析工具的优势,可以大大提高评估决策的科学性和准确性。     

Numerical simulation of a direct internal reforming solid oxide fuel cell using computational fluid dynamics method

A detailed mathematical model of a direct internal reforming solid oxide fuel cell （DIR-SOFC） incorporating with simulation of chemical and physical processes in the fuel cell is presented. The model is developed based on the reforming and electrochemical reaction mechanisms, mass and energy conservation, and heat transfer. A computational fluid dynamics （CFD） method is used for solving the complicated multiple partial differential equations （PDEs） to obtain the numerical approximations. The resulting distributions of chemical species concentrations, temperature and current density in a cross-flow DIR-SOFC are given and analyzed in detail. Further, the influence between distributions of chemical species concentrations, temperature and current density during the simulation is illustrated and discussed. The heat and mass transfer, and the kinetics of reforming and electrochemical reactions have significant effects on the parameter distributions within the cell. The results show the particular characteristics of the DIR-SOFC among fuel cells, and can aid in stack design and control.     

基于DDS技术构建信号发生器

介绍了一种基于51单片机和直接数字频率合成器(DDS)技术构建正弦信号发生器的设计。本设计具有信号带宽宽、频率转换时间短、可编程和全数字化、能够进行程序控制等优点。     

用DirectX实现地图3D展示及模拟行走

本文研究目的是为了找出从传统地图中获取三维信息并将其展现为真实三维立体图形的方法。研究运用了几何向量计算以及微软的Direct3D技术。本文主要阐述了用机器从地图采样三维信息,结合Direct3D及向量几何计算,构造出三维空间地形,然后实现模拟行走的技术,并提出优化方法。该研究取得成功,制作出了实现上述功能的软件。研究表明,采用现有地图作为信息源,运用了低价的硬件(扫描仪)和流行软件(Direct3D)技术制作出的三维展示工具,可节省地理研究成本。     

Isolation ofMycobacterium Tuberculosis 31 kDa antigen protein of diagnostic interest from culture filtrate using anti-ES-31 antibody by affinity chromatography

Proteins secreted into the culture medium byMycobacterium tuberculosis (M. tb) are shown to be source of antigens of immunodiagnostic interest. Anin vitro released 31 kDa antigen ESAS-7F isolated fromM.tb H₃₇Ra culture filtrate by salt precipitation, SDS-PAGE and cation exchange fast protein liquid chromatography (FPLC) was shown earlier to be a diagnostically important antigen fraction. In this report, we describe the isolation of ESAS-7F antigen using monospecific antibody coupled to sepharose CL-4B column. The percentage recovery of ESAS-7F antigen using affinity chromatography was approximately 8% of the total ES antigen proteins compared to 0.05% obtained by conventional purification steps using salt precipitation, SDS-PAGE and FPLC. Similar seroreactivity was observed by the antigen isolated by both the methods in indirect ELISA. Affinity chromatography helped in an increased recovery of ESAS-7F antigen and obviates the need for time consuming conventional purification steps.     

Comparison of two methods of estimation of low density lipoprotein cholesterol, the direct versus friedewald estimation

Current recommendations of the Adult Treatment Panel and Adolescents Treatment Panel of National Cholesterol Education Program make the low-density lipoprotein cholesterol (LDL-C) levels in serum the basis of classification and management of hypercholesterolemia. A number of direct homogenous assays based on surfactant/solubility principles have evolved in the recent past. This has made LDL-C estimation less cumbersome than the earlier used methods. Here we compared one of the direct homogenous assays with the widely used Friedewald’s method of estimation of LDL-C to see the differences and correlation. We used direct homogenous assay kit to estimate serum LDL-C and high-density lipoprotein cholesterol (HDL-C). Serum Triglyceride (TG) and Total Cholesterol (TC) was estimated and using Friedewald’s formula LDL-C was calculated. The LDL-C level obtained by both methods in 893 fasting serum samples were compared. The statistical methods used were paired t-test and Pearson’s correlation. There was significant difference in the mean LDL-C levels obtained by the two methods at the TG levels <200 mg/dl (p<0.02) and TC levels >150 mg% (p<0.001). The correlation coefficient (r) between Friedewald’s and direct assay estimation was 0.88. Friedewald’s method classified 23.5 % of patients as high cardiac risk whereas there were 17.58% by direct assay. Both had good correlation even though the serum triglyceride and total cholesterol levels affect the difference in LDL-C estimated by both methods. Taking into account the cost and performance, Friedewald’s method is as good or even better for classifying and managing patients.     

IEEE 802.11协议直扩技术的实现

802.11标准直扩技术主要是对网络的物理层(PH)和媒质访问控制层(MAC)进行了规定,其中对MAC层的规定是重点.同一物理层上可以互操作,逻辑链路控制层(LLC)是一致的,即MAC层以下对网络应用是透明的.这样就使得无线网的"(同网段内)多点接入"和"多网段互连",易于质优价廉地实现.     

求解弹塑性结构动力响应的变步距直接积分法

本文提出了一种适用于直接积分法的单步误差估计、步距自适应控制算法,并用于求解弹塑性结构的动力响应。本算法可以明显地提高直接积分法的计算精度和计算的过程收敛速度。     

琼脂糖固定化过氧化氢酶的电化学性能研究

利用琼脂糖（agarose）将过氧化氢酶（Cat）固定在热裂解石墨电极表面,制备Cat—agarose膜修饰电极．包埋在琼脂糖中妁过氧化氢酶与电极直接传递电子,在pH6．0的缓冲溶液中可得一对可逆的氧化还原峰,式电势为-0．343V（vs SCE）,这是过氧化氢酶辅基血红素Fe（Ⅲ）／Fe（Ⅱ）电对的氧化还原．其式电势随溶液的pH值增加而负移且成线性关系,直线斜率为-36．8mV／pH,说明过氧化氢酶的电子传递过程伴随有质子的转移．过氧化氢酶修饰电极．在16．5—278μmol／L的范围内,催化电流与过氧化氢浓度成线性关系．