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两参数马氏链的标准三点转移函数的密度族 被引量:4
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作者 刘韶跃 《湘潭大学自然科学学报》 CAS CSCD 1993年第3期26-27,共2页
简化了密度族的定义,并讨论它与4个偏微分方程组成立之间的关系。
关键词 转移函数 密度函数 马氏链 密度族
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一类随机游动上确界的密度的渐近性
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作者 程东亚 王岳宝 《数学物理学报(A辑)》 CSCD 北大核心 2009年第5期1206-1212,共7页
Kl(u|¨)ppelberg,Asmussen等研究了增量有有限负均值的随机游动上确界的密度的渐近性.该文则在Denisov等,程东亚和王岳宝的基础上,进一步研究了增量均值为负无穷的随机游动上确界的密度的渐近性.最后,为了说明常见重尾分布大多满... Kl(u|¨)ppelberg,Asmussen等研究了增量有有限负均值的随机游动上确界的密度的渐近性.该文则在Denisov等,程东亚和王岳宝的基础上,进一步研究了增量均值为负无穷的随机游动上确界的密度的渐近性.最后,为了说明常见重尾分布大多满足上述结果的条件,该文给出了一些分布族的性质. 展开更多
关键词 随机游动 上确界 负无穷均值 次指数密度族 渐近性
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两参数Markov链标准三点转移函数的几个结论 被引量:1
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作者 刘韶跃 李以泉 《湘潭大学自然科学学报》 CAS CSCD 1996年第4期15-16,共2页
本文对标准三点转移函数族及其密度族进行了简化,并得到向左、向下偏微分方程组成立的一个充分条件.
关键词 转移函数 密度族 马氏链 偏微分方程
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交联密度对脂肪族聚氨酯弹性体结构与性能的影响 被引量:26
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作者 朱广超 王贵友 胡春圃 《高分子学报》 SCIE CAS CSCD 北大核心 2011年第3期274-280,共7页
采用异佛尔酮二异氰酸酯(IPDI)与聚醚二元醇、三羟甲基丙烷(TMP)和1,4-丁二醇反应制备了具有不同交联密度的脂肪族聚氨酯弹性体.研究结果表明,当聚氨酯弹性体的硬段含量为40 wt%时,随着TMP含量的增加,聚氨酯弹性体的交联密度线性增加.... 采用异佛尔酮二异氰酸酯(IPDI)与聚醚二元醇、三羟甲基丙烷(TMP)和1,4-丁二醇反应制备了具有不同交联密度的脂肪族聚氨酯弹性体.研究结果表明,当聚氨酯弹性体的硬段含量为40 wt%时,随着TMP含量的增加,聚氨酯弹性体的交联密度线性增加.随着聚氨酯弹性体交联密度的提高,聚氨酯中硬段相的玻璃化转变温度由32℃降为21℃,聚氨酯中氨酯羰基的氢键化程度由83%降至63%,这个结果说明聚氨酯中软硬相的微相混合程度增加.聚氨酯弹性体的耐热性能随交联密度的提高而得到明显改善.力学实验结果表明,交联结构使弹性体的杨氏模量、100%定伸应力和硬度明显提高,断裂伸长率减小. 展开更多
关键词 脂肪聚氨酯 交联密度 形态结构 力学性能
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一类UMP检验及特性
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作者 李洪明 《呼伦贝尔学院学报》 2004年第4期23-24,35,共3页
密度函数为f(x,⊙)=exp|⊙T(x)+d(⊙)+s(x)|的子样,证明了:当T关于x严格递增且可微时,对每一个0≤⊙≤1存在一个UMP的水平α的检验,及相关特性。
关键词 UMP检验 密度函数 指数密度 单参数指数 充分统计量
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MODIFIED CLASSIC RISK FACTORS FOR CORONARY ARTERY DISEASE IN CHINESE HAN POPULATION 被引量:2
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作者 Han-bin Cui Sheng-huang Wang +7 位作者 Dong-qi Wang Chang-cong Cui Xin-yi Chen Xiao-min Chen Zheng Zhang Hong-kao Zhang Feng Bai Joseph B Muhlestein 《Chinese Medical Sciences Journal》 CAS CSCD 2007年第4期216-223,共8页
Objective To investigate the levels of cardiovascular disease risk factors and their relations to clinical phenotype associated with coronary artery disease(CAD).Methods The subjects were recruited from five independe... Objective To investigate the levels of cardiovascular disease risk factors and their relations to clinical phenotype associated with coronary artery disease(CAD).Methods The subjects were recruited from five independent cardiovascular centers.Coronary angiography was employed to define the CAD with stenosis in each major vessel ≥70% and control with stenosis <10% in every lesion.The classic risk factors including family history,body mass index,smoking habits,hypertension,diabetes mellitus,and serum lipid levels were surveyed according to established criteria.Associations between risk levels and clinical phenotypes were assessed by case control and correlation analysis.Results A total of 762 individuals were collected,including 481 men and 281 women,aged from 17 to 81(mean 60±10) years.The patients with CAD accounted for 55.5% of all participants,and controls 44.5%,respectively.Compared with the pattern in published data,our study showed that mean serum high density lipoprotein cholesterol(HDL-C) level was significantly lower(P<0.001) and triglycerides was significantly higher(P<0.001),while total cholesterol(TC) and low density lipoprotein cholesterol levels were comparative(both P>0.05).The prevalence of low HDL-C(<40 g/L) and hypertriglyceridemia(>150 g/L) were 27.2% and 41.4%,respectively.Mean serum levels of HDL-C and apolipoprotein A1 were significantly higher in female subjects than in male(P<0.001).Lower HDL-C functioned as an independent risk factor for CAD only in men(RR=2.8,95%CI:1.5-4.2,P<0.001),yet increased non-HDL cholesterol combined with diabetes mellitus and obesity seemed to play a key role in the development ofCAD in women.Similarity in risk association with CAD was found for hypertension and TC/HDL ratio in male and female subjects,while family history had no relationship with the presence of CAD.Conclusion It is remarkable that emphasis of intervention in future should be given on the prevalent low serum HDL-C and its strong risk correlation with the presence of CAD in male subjects of Chinese Han population. 展开更多
关键词 classic risk factors coronary artery disease high density lipoprotein cholesterol Chinese Han population
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