支持向量分类算法在5-HT3受体拮抗剂的构效关系研究中的应用

In this work, support vector classification （SVC） algorithm was used to build structure-activity relationship （SAR） model of the 5-hydroxytryptamine type 3 （5-HT3 ） receptor antagonists with 26 compounds. In a benchmark test, SVC was compared with several techniques of machine learning currently used in the field. The prediction performance of the model was discussed on the basis of the leave-one-out cross-validation. The results show that the accuracy of prediction of SVC model was higher than those of back propagation artificial neural network （BP ANN）, K-nearest neighbor （KNN） and Fisher methods.     

L-ficolin突变体原核表达载体的构建及表达产物的鉴定

目的构建L-ficolin突变体的原核表达载体，为研究L-ficolin的糖结合位点奠定基础。方法设计L-ficolin突变体基因上、下游引物，分别引入EcoRⅠ和XhoⅠ酶切位点。以插入L—ficolin M2（Val144Phe）和M6（Glu 307Asp）点突变的完整编码区基因的质粒pCDNA3-L-ficolin为模板，通过PCR扩增获得突变体的基因片段，将其克隆入原核表达载体pGEX—KG．然后通过酶切和序列测定对其进行鉴定；将此表达载体转化入表达菌BL21（DE3）pLvSs诱导表达。并采用SDS—PAGE对表达产物进行鉴定。结果经酶切及序列分析表明．成功地构建了重组原核表达载体pGEX-KG—L—ficolin—M2、pGEX-KG-L-ficolin—M6，SDS—PAGE显示目的蛋白大量表达。结论L—ficolin突变体融合蛋白可以在大肠杆菌中大量表达。为研究L-ficolin的糖结合位点打下基础。     

基于神经网络的垃圾邮件过滤

垃圾邮件的过滤是一个具有重要现实意义的课题．将交叉覆盖学习算法和向量空间模型等技术相结合可得到一种新的垃圾邮件过滤方法．实验结果表明该方法识别率较高，具有较强的实用价值．     

浅析俄语主从复合句中的分解型（复）句

本文就俄语主从复合句中分解型(复)句进行了整理、归纳和分析,以便学生更好地掌握与理解。     

Domain Coloring and the Argument Principle

Abstract

The domain-coloring algorithm allows us to visualize complex-valued functions on the plane in a single image—an alternative to before-and-after mapping diagrams. It helps us see when a function is analytic and aids in understanding contour integrals. The culmination of this article is a visual discovery and subsequent proof of the Argument Principle, which relates the count of poles and zeros of a meromorphic function inside a contour to the accumulated change in argument of the function around the contour. Throughout, I offer connections to standard learning goals of courses in complex variables.     

空间曲线的切线向量的求解方法

一个一般方程表示的曲面与一个参数方程表示的曲面的交线一般是一条空间曲线,根据两曲面方程的具体数学表示形式和难易程度,求其交线的切线向量的方法也要灵活。本文指出了切线向量的三种求法。     

Splicing-site recognition of rice (Oryza sativa L.)DNA sequences

INTRODUCTIONCorrectlypinpointingsplicing sitesingenomicDNAsequencesisnotaneasytask ,whichisofgreatimportancetothegenomeannotationandgenefinding .Intronsaregenerallydividedinto3classes,namelycalssI,classIIandcommonnu cleuspre mRNA .IntronofclassIandIIcango…     

基于SVPWM的异步电机矢量控制系统仿真

介绍了电压空间矢量脉宽调制(SVPWM)的基本原理,基本感应电机理论和坐标变换关系,给出转子磁场定向控制确定定向磁场在两相静止坐标系中位置角的算法,分析了基于SVPWM的感应电机转子磁场定向控制系统原理,并实现了SVPWM算法。通过MATLAB仿真软件对系统进行了仿真,给出了仿真结果。     

FDI、贸易开放与CO_2排放:以山东省为例

基于向量误差修正模型(VECM),利用山东省1995-2012年时间序列数据,实证分析了外商直接投资(FDI)和对外贸易开放水平对碳排放强度的影响,研究发现:FDI对碳排放强度具有抑制效应,对外贸易开放度对碳排放强度具有助长效应,且后者的弹性系数为前者的1.5倍。论文给出的政策建议:升级外商投资的能耗准入标准;创造良好外部条件利用外商直接投资技术溢出效应以加快山东省低碳技术发展步伐;及时淘汰内资企业中的落后产能,避免内资企业成为"污染天堂"的替罪羊;发挥山东省的示范和借鉴价值、挖掘区域经济的发展潜力,须建立和落实生态补偿制度等。     

Differences of math anxiety groups based on two measurements,MASS and EEG

This article investigated how mathematic anxiety (MA) of Korean middle school students could be reduced by comparing analytically their cognitive neuroscience and questionnaire results. We developed a three-hour Complex Treatment Program (CTP) on quadratic functions for the study. In the summer of 2016, we collected data of the pre and post MA questionnaires by Mathematics Anxiety Scale for Students (MASS), the percent of correct answers (PCA) and reaction time (RT) by E-prime program, and also brain-imaging data of the event related potentials (ERP) by Electroencephalograph (EEG) using computer-based functional F-G model. The result indicated the CTP to be effective with the group with higher math anxiety and the group with higher achievement respectively. The MASS result was verified with the better performance of PCA on type G, which was measured by E-prime program. Some interesting patterns were revealed on brain-imaging data by EEG, indicating more brain activities with the MA groups.