有限长高分子链特征标度对溶剂性质的依赖性

采用自洽平均场理论并结合蒙特卡洛方法考查不同溶剂中高分子单链回转半径与聚合度的标度关系。计算结果表明,在Θ溶剂中标度指数ν≈0.495,说明此时高分子链遵循理想链的行为;另一方面,在良溶剂中标度指数ν并非普适常数,而是随着溶剂性质的变化而改变,并且总是明显低于经典理论预测值0.6。分析指出,有限链长效应是造成这一偏差的重要原因。     

彩票的数学评判模型

对传统型彩票和乐透型彩票评奖方案的合理性问题进行研究.运用模糊数学理论建立模糊综合评判模型;通过构造吸引力效用函数建立吸引力效用评判模型;通过构造潜在购买量函数建立潜在购买量评判模型,评价得出比较合理的彩票销售方案.最后设计模型的优化方案并用蒙特卡洛优化法进行求解,给出改进评奖方案的建议.     

混合指数分布定数结尾时参数估计的Monte Carlo EM加速算法

应用Monte Carlo EM加速算法对于单参数混合指数分布在定数结尾场合的参数估计问题做了较深入的探讨,做出了模拟试验。     

Multispecies coalescent and its applications to infer species phylogenies and cross-species gene flow

Multispecies coalescent (MSC) is the extension of the single-population coalescent model to multiple species. It integrates the phylogenetic process of species divergences and the population genetic process of coalescent, and provides a powerful framework for a number of inference problems using genomic sequence data from multiple species, including estimation of species divergence times and population sizes, estimation of species trees accommodating discordant gene trees, inference of cross-species gene flow and species delimitation. In this review, we introduce the major features of the MSC model, discuss full-likelihood and heuristic methods of species tree estimation and summarize recent methodological advances in inference of cross-species gene flow. We discuss the statistical and computational challenges in the field and research directions where breakthroughs may be likely in the next few years.     

Numerical Simulation of Atomization due to Flood Discharges of Hydropower Stations

As a sanitary, reproducible and inexpensive en-ergy resource, the hydroelectric generation has beenincreasingly used in recent years. A great number ofhuge dams have been constructed in the narrow gor-ges, with the height of around 300 m and the flooddischarging powers ranging from10 billion to100 bil-lion W. The maximum unit discharges all exceed 200m3/(s·m). With the characteristics of flood dis-charge such as high head, large discharge, narrowgorges and high frequency, the existing dams ha…     

化学势和温度对储氢的影响

采用巨正则蒙特卡罗方法对碳钠米管的储氢过程做了模拟，分别讨论了化学势和温度对储氢的影响。     

Two dimensional potential mapping-Monte Carlo simulation

A very useful experiment of two dimensional potential mapping, namely electrolytic tank model, for graduate and post graduate level physics students is given here. Laplace's equation is solved for the above and the results are compared with the experiment. The agreement is so good that this is extended to complex problems. Monte Carlo simulation, an alternative to the above experiment, is developed for these complex problems and compared with the experimental results of electrolytic tank model.     

知识产权整体化风险管理的实证研究

首先,对广东自主创新型企业的知识产权风险进行分类与识别。其次,建立动态定量模型,发现广东自主创新型企业的知识产权风险主要集中在知识产权创造和运用环节,这两个流程环节中风险因素可解释变动百分比分别为35.75％和21.75％,相对而言知识产权管理和保护环节的风险较小,这两个流程环节中风险因素的可解释变动百分比分别为11.49％和6.43％。最后,对广东自主创新型企业的知识产权风险给出具体可操作的风险管理对策。     

The Poor Fit of Model Fit for Selecting Number of Factors in Exploratory Factor Analysis for Scale Evaluation

Model fit indices are being increasingly recommended and used to select the number of factors in an exploratory factor analysis. Growing evidence suggests that the recommended cutoff values for common model fit indices are not appropriate for use in an exploratory factor analysis context. A particularly prominent problem in scale evaluation is the ubiquity of correlated residuals and imperfect model specification. Our research focuses on a scale evaluation context and the performance of four standard model fit indices: root mean square error of approximate (RMSEA), standardized root mean square residual (SRMR), comparative fit index (CFI), and Tucker–Lewis index (TLI), and two equivalence test-based model fit indices: RMSEAt and CFIt. We use Monte Carlo simulation to generate and analyze data based on a substantive example using the positive and negative affective schedule (N = 1,000). We systematically vary the number and magnitude of correlated residuals as well as nonspecific misspecification, to evaluate the impact on model fit indices in fitting a two-factor exploratory factor analysis. Our results show that all fit indices, except SRMR, are overly sensitive to correlated residuals and nonspecific error, resulting in solutions that are overfactored. SRMR performed well, consistently selecting the correct number of factors; however, previous research suggests it does not perform well with categorical data. In general, we do not recommend using model fit indices to select number of factors in a scale evaluation framework.     

Alternative Monte Carlo Approach for General Global Illumination

Ithasbeenwellknownthatglobalilluminationsimu latesthelighttransportamongallthesurfacesandthelightsourcesinavirtualsceneconsideringdiffusereflection/refrac tionandspecularreflection/refraction .Duetosimplicity,generalityanddimensionalindependence,MonteCarlomethodorrandomwalkmethodisoneofthemostimportantmethodsforsolvingthedifficultglobalillumination .Inpartic ular,MonteCarloisthelastresortwhenallotheranalyticalornumericalmethodsfail[1 ] .　　Lighttransportormultiplelightinteractionsamongthesu…