汽车动力总成悬置骨架的拓扑优化设计

以某商用车动力总成的悬置骨架为分析对象,基于变密度法建立拓扑优化的数学模型及其求解方法;运用有限元软件Hyperworks中的Optistruct模块将拓扑优化方法应用到该商用车动力总成的悬置骨架结构设计中,对单工况下的骨架结构进行优化设计。根据优化的结果并结合生产经验,设计出新悬置骨架的结构。最后用ABAQUS软件对悬置总成进行应力、变形和体积的计算。结果表明,经过优化的悬置骨架安全性能得到提高,重量减轻。     

“Noah’s Ark”: its relationship to the Telçeker earthflow,Mount Ararat,Eastern Turkey

The southern slopes of Mount Ararat are formed of an interbedded sequence of limestones and mudrocks in which a 1,000 m deep valley has been eroded. During the glacial/periglacial climates of the past, mass movements took place in this mountainous area, resulting in a debris mantle on the slopes and a blocky colluvium in the valley floor. The 150 m × 50 m × 4 m high ship-like feature, sometimes referred to as “Noah’s Ark”, is considered to be a large discontinuity-bounded block of Miocene limestone which has slumped and crept downslope on the weak Eocene clays. The shape of the feature has been modified by abrasion caused by passing earthflow material as well as ice melt and limestone dissolution processes.      

宁夏贺兰山东麓葡萄卷叶病病原鉴定研究

宁夏贺兰山东麓，7月中旬在酿酒葡萄红色品种(赤霞株)的基部叶片上出现红色斑点，8月份进入发病高峰期。病株叶片变为暗红色、并变脆、增厚、叶缘下卷，浆果可溶性固形物降低2～4度。采用负染电镜法和双抗体夹心酶联免疫吸附试验法鉴定，为葡萄卷叶病毒病。     

基于3D-GIS的智慧泰山景区信息集成平台

论述了在智慧地球框架下构建智慧泰山景区信息集成平台总体方案.该方案从网络化感知、专业化规则和智能化服务3个方面将包括GPS、视频监控、门禁票务、遥感监测等实时数据有机地融合到一起,形成了一个智慧化的泰山景区综合服务体系.智慧泰山景区信息集成平台建成后已经成功地应用于泰山景区的虚拟旅游服务、客流监控与管理、病虫害监测等多...     

典型火炮静刚度分析与改进设计

炮架是火炮的支撑部件,其静刚度对火炮的射击精度有重要影响。基于典型火炮结构的相似性,首先建立适用于典型火炮炮架的简化力学模型,提出检验典型炮架静刚度的评估方法。根据火炮力学模型建立典型火炮初始设计的有限元模型,进行多工况下的静力计算,获得了炮架的刚度性能、位移云图及应力云图,讨论了火炮炮架在不同工况下的变形特征和薄弱环节;其次,根据炮架的变形特征和薄弱环节,采用“改进-评估-再改进”的不断改进优化的策略,最终给出一个较为满意的设计方案。与原设计方案相比,新方案在重量略有增加的条件下,刚度有较大幅度提高,对火炮性能提升有很明显的作用。该研究对火炮炮架的静刚度分析与设计具有一定的参考意义。     

一种观察细胞骨架的简易整装电镜制样方法

本文介绍一种显示细胞骨架的简易有效的整装电镜制样方法。24孔培养板上钻以直径为2.5mm的圆孔,覆上0.25%的Formvar膜后,成为培养细胞的良好支撑物,然后在原位对培养的细胞进行抽提、固定和二氧化碳临界点干燥,相差显微镜下观察、选择和定位,再以浸湿的单目铜网置于圆孔上,自然干燥后取上已覆有Formvar膜的铜网,即可进行标本的观察。该方法材料来源容易、经济,操作简便,成功率较高,并可减少盲目的电镜观察及人工假象,所得的细胞骨架图像清晰。     

从郊天与封禅看玉器在古代国家宗法政治中的地位

为了进一步了解中国远古玉文化在古代国家宗法政治中的作用和地位，从历代礼祭活动中遴选出两个重要礼典——郊天和封禅，详细阐述了郊天与封禅礼祭中的用玉礼制，并分析了玉器在宗法政治中发挥的重要作用．指出中国远古玉文化与中国古代国家统治理论有着不可分割的依存关系，在中华民族文化中占有重要的历史地位。     

INVESTIGATION OF ACID DEPOSITION EFFECTS ON SOUTHERN APPALACHIAN RED SPRUCE (Picea rubens) BY DETERMINATION OF CALCIUM,MAGNESIUM, AND ALUMINUM IN FOLIAGE AND SURROUNDING SOIL USING ICP-OES

Red spruce (Picea rubens) are conifers found at high elevations (above 1370 m) sites in the Southern Appalachian Mountains. A decline of red spruce forests in the Southern Appalachian Mountains caused by atmospheric acid deposition has been reported since the 1970s. Acid deposition leaches essential nutrients (calcium and magnesium) out of the soil and increases the availability of toxic metals (aluminum) to plants. Acid deposition effects on red spruce forests were investigated by determining aluminum, calcium, and magnesium in foliage and surrounding soils using inductively coupled plasma optical emission spectrometry (ICP-OES). There was some correlation in nutrient or toxic metal concentrations found in the foliage or surrounding soils of red spruce trees with respect to elevation and geography of red spruce forests located in the Southern Appalachian Mountains. The majority of the results indicated that foliar nutrient or toxic metal concentrations from red spruce trees did not correlate with soil metal concentrations. Life stage of red spruces trees were independent of foliar or soil metal concentrations. A previously developed model using soil calcium/aluminum molar ratios suggested that almost all sample sites located in the Southern Appalachian Mountains are at high risk of adverse forests health effects. A comparison of red spruce sapling foliar calcium/aluminum ratios at Clingman's Dome, North Carolina/Tennessee, suggested a possible improvement since the 1980s in red spruce forest health. A comparison of sapling red spruce foliar calcium and magnesium concentrations with previous studies, which spanned 40 years, at Richland Balsam, North Carolina, suggested an improvement in red spruce health since 1994.     

Escalating commitment in the death zone: New insights from the 1996 Mount Everest disaster

The procession of people and organisations that pour resources into evidently failing causes is surprising and seemingly never-ending. This phenomenon, which is called “escalating commitment” (Staw, 1976), refers to situations in which people are incapable of turning future disasters into sound current decisions. The purpose of this paper is to use the, in project management literature (Kloppenborg and Opfer, 2002), non-traditional case of the 1996 Mt Everest disaster to explain and analyse escalating commitment determinants and processes. Not only does the paper identify and add a determinant to escalation but it also treats determinants and processes in a novel and intertwined fashion. The conceptual developments and findings suggest that escalating commitment strives on conditions that are inherent to any project, which consequently project managers should be aware of. Based on the results project failures could be better explained and understood by examining several explanatory levels simultaneously.     

基于混合精度模型的城市山体视觉分析研究——以南京紫金山为例

随着中国城市化进程的不断推进与深入,城市空间中的自然山水景观视觉价值与重要性受到更多关注.以城市山体为研究对象,构建了一种基于混合精度模型的定量视觉分析框架,从"观"与"被观"2个方面提出了若干视觉量化指标.结合南京紫金山案例研究,从客观角度深入分析紫金山在南京老城中的空间视觉特征,利用基于混合精度模型的定量分析方法获...