可摘局部义齿不同加载条件下的三维有限元分析

为分析对比3种可摘局部义齿修复重建肯氏I类缺失牙列的生物力学效果，对中国力学虚拟人数据库中现有模型进行改建，以此为基础形成三臂卡环固位、RPI卡环固位和种植体支持的RPI卡环固位3种不同方案的几何及有限元模型，导入ABAQUS6.5 1完成相应有限元分析，采用垂直载荷和斜向载荷，较好地模拟了口腔咀嚼过程.分析结果表明，RPI卡环固位义齿对抗垂直载荷与斜向载荷能力均优于三臂卡环固位义齿；有种植体支持的RPI卡环固位义齿对抗斜向载荷能力优于无种植体支持的RPI卡环固位义齿.     

速写中的衣纹线的表现

速写是以对形象敏锐的观察和简练、概括并迅速表现为特点的一种绘画种类.而衣纹线又是学好人物速写的关键.文章就衣纹线的分类、组织及特殊衣纹线的表现进行了阐述.     

On the Differences in Single- walled Carbon Nanotubes and Multi- walled Carbon Nanotubes

碳纳米管作为最重要的纳米材料之一,其研究越来越得到人们的重视.文章主要综述了单壁碳纳米管和多壁碳纳米管的差异.     

新时期高校党员领导干部加强党性修养研究

新时期党中央对党员领导干部加强党性修养提出了一系列新的要求。从高校党员领导干部加强自身党性修养和加强普通党员师生党性修养两个方面,分析了现阶段高校党员领导干部党性修养存在的问题;从更加注重坚定理想信念、更加注重严守党纪党规、更加注重坚持立德树人、更加注重提升能力水平四个方面,探讨了加强高校党员领导干部党性修养的对策和建议。     

Vegetation effects on mean daily maximum and minimum surface air temperatures over China

Changes in the daily maximum (Tmax) and minimum (Tmin) surface air temperatures and the associated temperature extremes have severe consequences on human society and the natural environment. In this study, we assess vegetation effects on mean Tmax and Tmin over China by computing a vegetation feedback parameter using the satellite-sensed Normalized Difference Vegetation Index (NDVI) and observed temperatures for the period 1982–2002. In all seasons, vegetation exerts a much stronger forcing on Tmax than on Tmin, and thus has a substantial effect on the diurnal temperature range (DTR) over China. Significant positive feedbacks on Tmax and the DTR occupy many areas of China with the feedback parameters exceeding 1°C (0.1 NDVI)–1, while significant negative effects only appear over the summertime climatic and ecological transition zone of northern China and some other isolated areas. Also, the vegetation feedbacks are found to vary with season. In areas where significant feedbacks occur, vegetation contributes to typically 10%–30% of the total variances in Tmax, Tmin, and the DTR. These findings suggest that vegetation memory offers the potential for improving monthly-to-seasonal forecasting of Tmax and Tmin, and the associated temperature extremes over China. Meanwhile, the limitations and uncertainties of the study should be recognized.     

一种创新的智能英语学习系统的设计

缺乏必要的语言学习环境,导致教学效率不高,这个问题多年来困扰着外语教学工作者。为此,提出一种低成本、高效率的解决方案,用以研发英语学习系统,引导英语教学体系改革,即借助人工智能(AI)和计算机网络技术,模拟实际生活,构建共享的多媒体语言教学环境。论证并设计了一种创新的智能英语学习系统(IELS),提出了系统目标,并就功能实现做出了详细的规划。     

Complete monotonicity of the probability of ruin and de Finetti’s dividend problem

This paper studies the complete monotonicity of the probability of ruinψin the the classical risk model and the classical risk model that is perturbed by a diffusion.As a byproduct,the authors give an alternative proof to a result on the optimal dividend problem due to LoefFen(2008).     

8G机车主断路器低压操纵机构改造

主断路器是电力机车的总保护、总开关,从2008—2010年主断路器运行情况调查结果分析得出：94的主断路器故障出现在低压操纵机构,而低压操纵机构故障的98发生在启动机构和电气连锁两部分。通过分析最近3年主断路器发生故障的原因,对其进行了技术改造。     

Temperature-induced fractionation of oxygen isotopes of diatom frustules and growth water in Lake Sihailongwan in Northeast China

Diatom oxygen isotopes have been widely applied in quantitative reconstruction of the paleoclimate and paleoenvironment, but have rarely been reported in China. In the present study, Lake Sihailongwan in Northeast China was selected for detailed investigation of oxygen isotopic fractionation between diatom frustules and lake water induced by growth temperature. This study involved a 2-year period of field monitoring of the lake water temperature at multiple depths and biweekly collections of traps for both sediment and water at shallow and bottom depths (7 and 49 m below the lake surface, respectively), diatom separation and purification of the trap sediments, and oxygen isotope measurement for diatom silica and lake water samples. The conditioned experiment conducted herein demonstrated that the laboratory device, methods and techniques used in this study were capable of generating reliable data for the typical oxygen isotope composition of diatom frustules. The data obtained revealed a prominent linear relationship between the oxygen isotope composition of the modern diatom and lake temperature during growth. The fractionation coefficient was about −0.185‰/°C−0.238‰/°C in the temperature range of 3.6–24°C, which is consistent with the observations from various aquatic environments and laboratory culture with different diatom taxa. These findings provide strong support for the dominant control of the growth temperature on the oxygen isotope fractionation between the diatom frustules and ambient water. A notable difference in the fractionation coefficient was observed between the surface and bottom diatom oxygen isotopes, suggesting that various depositional processes and taphonomic effects influenced the surface and bottom trap samples. Another factor leading to this difference may be that enrichment by evaporation and dilution by rainfall have a stronger influence on the surface. Overall, the results presented here demonstrate significant progress in evaluation of diatom oxygen isotopes in China and draw attention to the differences between surface and bottom diatom oxygen isotope compositions.     

浅谈节能环保建筑设计

文章介绍了建筑节能工作存在的问题,并提出了应采取的措施.