张学良官邸从权力主义到人文主义的近代建筑转型

张学良官邸是沈阳规模最大的国家级近代建筑遗产之一,由张学良将军和其父奉系军阀张作霖在沈阳老城内营建.张学良官邸建筑风格多样,建筑类型丰富,其设计和施工代表了20世纪20年代本国工匠和建筑师的最高水平.该文通过对官邸的分析和研究,寻找其多种风格形成的主要原因,阐述了由于父子不同的人生观和价值观其官邸建筑形式的不同,剖析了...     

Trace element concentrations in hair of healthy Chinese centenarians

Trace element concentrations, as indicators of micronutrient status of healthy centenarians, have not been widely analyzed. This study aimed to assess trace element concentrations in the hair of healthy centenarians. The effects of gender and age on element concentrations were also investigated. Eleven trace elements (Al, Ba, Cd, Cr, Cu, Fe, Mo, Pb, Se, Sr and Zn) in the scalp hair of 107 healthy Chinese centenarians were examined. The overall reference values (RVs) in mg/kg for the hair concentrations of trace elements in centenarians were as follows: Al, 14.95; Ba, 2.68; Cd, 0.06; Cr, 0.59; Cu, 6.21); Fe, 19.37; Mo, 0.50; Pb, 4.64; Se, 0.37; Sr, 4.84; and Zn, 154.37. Data analysis found that only Cu and Zn concentrations show a normal distribution, and there is no significant difference between males and females in any element except Zn. However, the levels of Al, Cd, Cr, Fe, Mo, Pb decrease and the levels of Ba, Cu, Se, Sr, Zn increase with age in the centenarian cohort. Results also revealed that sufficient Zn and Se concentrations as well as low exposure to heavy metals pollution contribute to the longevity of centenarians. The results imply the possibility of manipulating trace element concentrations, especially Zn and Se concentrations in tissues, as a means for therapeutic modality in geriatric disease.     

2D数字阀阀芯受力分析及研究

介绍了2D数字阀的基本结构及工作原理,提出了2D流量控制概念。研究了由径向力引起的液压卡紧现象。通过Fluent软件对数字阀内部进行流场分析,得出2D阀芯弓形槽处壁面所受的压力分布,并对阀芯受到径向力的原因进行了分析,提出了减小2D阀阀芯卡紧力的一些措施。     

一次耐人寻味的招聘会

经过几年的打拼,天瑞羊业公司已由一个业务名不见经传的小养殖场成长为叱咤风云的大集团了.随着企业的发展壮大,人才日益匮乏起来,公司高层准备招聘一些本专业的高端人才,学历拟定在本科以上.为了结合实践,将招聘地点定在公司麾下的一个核心种羊场,而为了吸引优秀人才,公司不仅承诺提供优厚的待遇,还利用媒体大肆渲染,在有关报刊、网络上都浓墨重彩地宣传了一番.     

人行走引起的楼板振动舒适度设计

由于现代建筑的楼板结构跨度越来越大、刚度越来越小,人正常行走引起的楼板振动舒适度问题日益突出,目前国内尚无统一的舒适度标准和设计方法,本文在国内外相关研究基础上,提出了楼板振动的舒适度设计标准,由动力方程推导出了楼板振动的加速度计算公式,并针对楼板振动的特点,对舒适度设计应采用的荷载取值、分析工况进行了详细说明,可为实...     

楼板振动舒适度控制的标准研究

由于新技术、新材料等的发展和应用,现代楼板结构跨度越来越大、刚度越来越小,楼板振动舒适度问题目益突出,但目前国内尚无统一的楼板振动标准。本文在国内外大量舒适度实验研究的基础上,对不同活动状态和建筑使用类别,提出了振动加速度的限值规定,以满足人们对建筑使用舒适性的要求,为工程设计中的楼板振动舒适度设计提供参考。     

不同竖向荷载下PHC管桩水平承载性能研究

在桩基设计中通常分别确定单桩的竖向和水平向承载力,而不考虑竖向荷载与水平荷载之间的相互作用对桩承载力的影响,这显然不能反映桩的真实受力状况。本文通过现场的载荷试验,分析了PHC管桩在不同竖向荷载下的水平承载性能,利用有限元软件ANSYS对该实例进行数值模拟,结果表明：在先施加竖向荷载再施加水平荷载时,存在一个最优的竖向...     

A safety assessment of the new Xiangyun phosphogypsum tailings pond

Phosphogypsum tailings are piled up to form a phosphogypsum tailings pond. In the design and operation stages of a tailings project, the stability of the tailings pond, the control capacity for flood, and the reliability of the drainage and safety monitoring facilities should be fully evaluated. Key contents of the safety assessment are analyzed in view of the new Xiangyun phosphogypsum tailings pond, which is currently in the design stage. Flood routing calculation results show that the pond cannot meet the requirements of the China National Standards Safety Code in the condition of a 500-year flood even if the drainage facilities operate normally. Seepage and static stability of the tailings pond are investigated through numerical and limit equilibrium methods. The results indicate that the sliding stability can meet the requirements along the starter dike profile. Dynamic calculation results show that the liquefied area is at the top of the dam slope and it cannot influence the dam safety. The aspects of safety monitoring design that require attention are also proposed.     

行走城市:旧金山

旧金山属于旧金山海湾大都市区的一部分,西濒太平洋,北临金门海峡,东部是旧金山湾,人口约有80万人.作为美国第一座制定涉及整个城市的城市设计政策(1971年)的城市,旧金山在城市设计发展史上具有特殊的地位.     

“上软下硬”地层条件下地铁车站合理埋深确定

以青岛地铁工程为实例,确定敦化路车站的合理埋深和最佳埋深.青岛地层呈“上软下硬”的特点,传统的覆跨比理论不能很好的确定暗挖车站埋深.通过对不同埋深条件下车站的围岩第一主应力、竖向位移、安全系数的数值模拟分析和研究,发现微风化岩层的位置对埋深确定有决定影响,通过综合分析,确定敦化路地铁车站最佳埋深即埋深为14.5 m,且...