提高女生短跑成绩的教法手段之研究

采用正交实验和教学实践相结合的研究方法,对提高初三女生短跑成绩的教法手段进行了研究;正交实验结果显示,影响女生50米跑成绩的因素其主次顺序为:绝时速度、速度力量、加速能力、速度耐力,最优搭配方案为A2B2C3D1;通过教学实践检验,新的搭配方案明显地提高学生的运动能力.     

Sequential design for nonparametric inference

The performance of nonparametric function estimates often depends on the choice of design points. Based on the mean integrated squared error criterion, we propose a sequential design procedure that updates the model knowledge and optimal design density sequentially. The methodology is developed under a general framework covering a wide range of nonparametric inference problems, such as conditional mean and variance functions, the conditional distribution function, the conditional quantile function in quantile regression, functional coefficients in varying coefficient models and semiparametric inferences. Based on our empirical studies, nonparametric inference based on the proposed sequential design is more efficient than the uniform design and its performance is close to the true but unknown optimal design. The Canadian Journal of Statistics 40: 362–377; 2012 © 2012 Statistical Society of Canada     

AgCl团簇结构及性质的研究

用HF/STO-3G方法优化了(AgCl)n(n≤5)团簇结构,并计算了能隙、电离势、电荷布局数、偶极钜、(AgCl)2和(AgCl)3的红外光谱。结果表明:(AgCl)3结构最稳定;平均结合能随着尺寸增大趋于平缓;(AgCl)n团簇具有很强的绝缘性;结构对称性越高,电荷布局数越均匀,偶极钜越小;最强的(AgCl)2和(AgCl)3的红外光谱线分别位于142cm-1和232cm-1处。     

Performance-Related Reliability Analysis Methodology of Computer Networks

Based on the bottlenecks in current performance-related network reliability (PRNR) research, this article selects network time delay as PRNR evaluation foundation, and defines PRNR measure as the probability that the actual network delay is no bigger than the required value during network long-term operating under the specified conditions of resource allocation and network operating environment. To obtain PRNR, a novel threshold-optimization-based network traffic model is proposed to model real network traffic. In this model, the actual network traffic is divided into two different parts—a-traffic with burst characteristic, and b-traffic with steady characteristic—according to the optimized threshold value obtained with Particle Swarm Optimization (PSO). Analysis to PRNR is carried out in two different time levels—macro-time level and micro-time level—to avoid the difficulties resulting from the great difference in reliability and performance dimension. In the macro-time level, the number of the operational network workstations varying with random failures is obtained. In the micro-time level, the packet delay is analyzed with the number of the operational workstations as a parameter. Combing the analysis in these two time levels together, the integrated PRNR model is established, and influences of different parameters are analyzed.     

车行横洞施工对隧道主洞变形的影响

针对隧道车行横洞施工对主洞结构产生影响，以运城 灵宝高速公路中条山隧道工程为依托，采用现场试验和三维有限元仿真的方法，对车行横洞施工阶段主洞的变形规律进行了研究。研究结果表明：车行横洞施工对主洞的影响，在时间上主要表现在交叉口初支拆除和横洞的第1个开挖步，随着横洞开挖深度的增加，主洞结构的变形逐步趋于稳定;车行横洞施工对隧道主洞围岩变形影响主要表现为主洞拱顶下沉量增加和开挖侧拱脚水平位移减小，主洞未开挖侧拱脚水平位移影响不大。     

Ti3+自掺杂纳米TiO2的制备、表征与可见光催化活性

以Ti H2和H2O2为原料,采用水热法制备了米粒状Ti3+自掺杂的TiO2纳米颗粒.采用X-射线衍射(XRD)、透射电子显微镜(TEM)、高分辨透射电子显微镜(HRTEM)和X-射线光电子能谱(XPS)对所制备样品的结构、结晶性、形貌和元素的存在状态进行了表征分析.电子顺磁共振谱(ESR)结果表明所制备的样品中含有晶格Ti3+和表面Ti3+.紫外—可见(UV-Vis)漫反射光谱表明这种Ti3+自掺杂的纳米TiO2在可见光区中有较强的吸收.在可见光辐射下,所制备的样品具有优于商业化P25 TiO2的光催化分解水和光催化降解次甲基蓝(MB)溶液的性能.其中160℃下水热处理27 h所得样品光催化降解MB的性能是P25 TiO2的9倍,而光催化分解水制氢的性能是P25 TiO2的12.5倍.     

美国早期教师教育培养方案及启示——以路易斯安那州立大学的pk-3项目为例

路易斯安纳州立大学（LSU）的一个教育工作团队创立了一个针对学前班(pre-kindergarten)至小学三年级的早期教师培养方案,简称pk-3项目,它是大学、小学及幼儿教师合作开发的。通过对该项目的背景、实施过程以及学生评价的分析,以期为我国幼儿教师培养提供有效借鉴。     

“第三只手”：一个边贸市场的民间权威及其成长

中、越、老边境线附近的滇村“三号街”是当地人自发形成的边境贸易市场,经由传统社会生活方式所确立的民间权威,是维系“三号街”市场运行的重要力量。在传统的乡村社会,无论行政权力还是市场本身,都无法凭借一己之力建构稳固的经济体系并维持其运行,而民间权威在地方社会的经济生活中是不可或缺的。