检索结果-南通市图书馆

Dynamic response characteristics of a circular lined tunnel under anisotropy frost heave of overlying soil at the tunnel portal section in cold regions

引用

Journal of Mountain Science 2023年第5期20卷 1424-1440页

作者： ZHANG Shuo-cheng chen wen-hua School of Civil Engineering Beijing Jiaotong UniversityBeijing 100044China

The rapid development of traffic engineering in cold regions and its consequent problems need to be *** this paper,the dynamic response characteristics of the tunnel portal section in cold regions with harmonic load acting on the lining were studied in the frequency *** lining is in close contact with the frozen soil,and there is relative movement between the frozen and unfrozen soil due to the phase *** analytical solution of the vibration of tunnel portal section caused by the harmonic load acting on the lining was derived under the consideration of the anisotropy frost heave of overlying *** on the continuity conditions and boundary conditions,the undetermined coefficients were obtained,and the analytical solutions for different medium displacements and stresses of the cold-region tunnel system were *** vertical pressure coefficient was equivalently simplified as a variable that could be used to replace the thickness of the overlying soil above the *** analysis of the parameter model shows that the change of the medium parameters(lining,frozen,and unfrozen soil)affects the circumferential stresses,the radial displacements and their peak frequencies of the *** example,the increase of density ratio of tunnel lining to frozen soil decreases the radial stresses of the frozen and unfrozen soil;the increase of volumetric frost heaving strain of the frozen soil increases the radial displacements of the frozen surface and decreases the stability of the frozen surface;the increasing of thickness of the frozen soil significantly reduces the radial displacement of unfrozen soil at dimensionless radius η=4.5 compared with that of frozen soil at η=1.5.

关键词： Frost heave Tunnel portal section Relative movement Dynamic response characteristics Cold region

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Variations and trends of trans-boundary runoff in the longitudinal range-gorge region

引用

Journal of Mountain Science 2017年第2期14卷 316-324页

作者： YU Yan-ling PAN Feng LIU Xin-you chen wen-hua HE Da-ming Water Conservancy College Yunnan Agricultural UniversityKunming 650201China Key Laboratory of International River and Transboundary Eco-security Yunnan UniversityKunming 650091China Electric power engineering college Kunming University of Science and TechnologyKunming 650093China State Key Laboratory of hydrology water resources and hydraulic engineering Hohai UniversityNanjing 210098China Hydrology and water resources Bureau Yunnan ProvinceKunming 650106China Baoshan College Baoshan 678000China

The mountainous hydrological process usually shows high variation to climate change and human action. In the Longitudinal Range-Gorge Region（LRGR）, Southwestern China and Southeast Asian, the transboundary runoff variations are much more sensitive and complex under the interaction of climate change, ＂corridor-barrier＂ functions in LRGR,and dams building. In this paper, based on the long hydrological records（1956-2013） from three mainstream hydrological stations in Nu River,Lancang River, and Red River, the region runoff variations were analyzed. The results show out： i） the regional runoff changes were strongly influenced by the ＂Corridor-Barrier＂ functions in LRGR from west to east, the variability extent of annual runoff increased, but tended to decrease after 2009 and the reduced extents also increased; ii） the annual runoff change in the three rivers had high concentration degrees; iii） there were periodicities of 33 years of runoff change in Nu River and Lancang River, and 30 years in Red River, and the lower flow period would continue for 8-9 years in Nu River and Lancang River but only for 4 years in Red River; iv） since 2010, as the two mega dams of Xiaowan and Nuozhadu built in Lancang River mainstream, their variations of annual runoff were quite different. The research results could offer a scientific base for sustainable utilization,conservation, and management of the regional water resources

关键词： Runoff variations Climate change "Corridor-barrier" functions Longitudinal rangegorge region Transboundary rivers

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Toward Acetylcholine Sensor Devices: Facile Synthesis of 2-Cyanoresorcin[4 ] arene and Its High Affinity toward Acetylcholine

引用

有机化学 2003年第Z1期23卷 400-401页

作者： TAN Song-De WEI Ying WANG Bo XU Zun-Le chen wen-hua School of Chemistry and Chemical Engineering Sun Yat-Sen University Guangzhou 510275 School of Chemistry and Chemical Engineering Sun Yat-Sen University Guangzhou 510275 School of Chemistry and Chemical Engineering Sun Yat-Sen University Guangzhou 510275 School of Chemistry and Chemical Engineering Sun Yat-Sen University Guangzhou 510275 School of Chemistry and Chemical Engineering Sun Yat-Sen University Guangzhou 510275 CREST Japan Science and Technology Corporation (JST) Japan

　　The biological importance of acetylcholine spurs the efforts to construct its synthetic receptors with the aims to develop acetylcholine sensor devices. Among the various building blocks used to synthesize artificial acetylcholine receptors, resorcin [4 ]arenes, [1] which can be conveniently obtained from the acid-catalyzed condensation of resorcinol with aldehyde, were shown to serve as one of the most strongest synthetic receptors for choline type guests.……

关键词： building blocks

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Multi-slice spiral CT angiography in evaluating donors of living-related liver transplantation

引用

Hepatobiliary & Pancreatic Diseases International 2007年第4期6卷 364-369页

作者： chen, wen-hua Xin, Wei Wang, Jie huang, Qing-Juan Sun, Yi-Fang Xu, Qing Yu, Sheng-Nan Suzhou Univ Affiliated Hosp 3 Dept Radiol Changzhou 213003 Peoples R China Nanjing Med Univ Affiliated Hosp 1 Dept Radiol Nanjing 210029 Peoples R China

BACKGROUND: During the past years, the number of liver transplantation has increased greatly, but the number of available organs has not increased. In view of the critical shortage of organs, the indications for living-related liver transplantation (LRLT) have broadened since experience with the procedure has been achieved. This study was undertaken to assess the value of multi-slice spiral CT (MSCT) angiography in evaluating the hepatic arterial and veinous anatomy of potential donors for LRLT. METHODS: MSCT was performed after intravenous injection of contrast material at 3 ml/s. The total dose was calculated as 2 ml/kg. Twenty LRLT donors (2 men and 18 women) were subjected to MSCT angiography of hepatic blood vessels. These were generated by volume rendering and maximum intensity projection, while curved planar reformation was added in 5 patients. RESULTS: We identified 10 important hepatic vascular variants in 9 of the 20 donors (4 arterial, 4 venous, and 2 portal venous variants). In hepatic arterial variants, two had a replaced right hepatic artery arising from the superior mesenteric artery, an accessory right hepatic artery from the superior mesenteric artery and a replaced left hepatic artery arising from the left gastric artery. In hepatic venous variants, three had an accessory inferior right hepatic vein and one had two accessory inferior right hepatic veins. In hepatic portal venous variants, two had trifurcation of the main portal vein. CONCLUSIONS: As a non-invasive and reliable method, MSCT angiography is of value in the clinical evaluation of LRLT donors. MSCT angiography should be recommended as a routine preoperative examination for potential LRLT donors.

关键词： multi-slice spiral CT living-related liver transplantation donor angiography

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

高温高湿环境下高铁隧道洞口段热湿病害分析

引用

铁道工程学报 2016年第11期33卷 102-105,119页

作者：陈文化北京交通大学北京100044

研究目的:南方铁路隧道的洞口段长期处于高温高湿环境,受热湿反复作用,衬砌及围岩发生劣化,进而产生裂纹或裂纹扩张,影响隧道结构的寿命与安全。本文通过理论和模型分析,结合现场测试研究,得到隧道洞口段热湿病害产生机制,为高温高湿环... 详细信息

研究目的:南方铁路隧道的洞口段长期处于高温高湿环境,受热湿反复作用,衬砌及围岩发生劣化,进而产生裂纹或裂纹扩张,影响隧道结构的寿命与安全。本文通过理论和模型分析,结合现场测试研究,得到隧道洞口段热湿病害产生机制,为高温高湿环境下洞口段隧道病害整治提供理论依据,目前此研究国内外仍处空白状态。研究结论:(1)基于增量理论及湿度应力场理论建立了湿度和温度影响下岩体的增量型弹塑性体胀本构方程,推导了热湿应力表达式;(2)依据某隧道现场监测数据,计算了围岩温度场、湿度场与热湿应力及季节性变化情况,分析了不同衬砌和岩石导热系数、厚度对热湿应力的影响;(3)研究发现热湿应力纵向影响深度在3 m以上,给出了热湿应力在隧道洞口段分布与发展规律以及累积效应;(4)本研究成果可为高温高湿地区高铁洞口结构设计和病害整治提供依据。

关键词：高温高湿环境热湿破坏铁路隧道洞口段围岩与衬砌

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

复合热处理对CrWMn钢组织的影响

引用

金属热处理 2000年第2期25卷 40-41,49页

作者：陈文华南京航空航天大学南京210016

研究了CrWMn钢经复合热处理后的组织变化。结果表明,采用790℃/680℃循环球化退火可代替常规等温球化退火,并能缩短球化退火周期,节约能源。采用高温固溶处理加790℃/680℃循环球化退火,可获得高弥散度碳化物,使CrWnMn钢的最终组织得到... 详细信息

研究了CrWMn钢经复合热处理后的组织变化。结果表明,采用790℃/680℃循环球化退火可代替常规等温球化退火,并能缩短球化退火周期,节约能源。采用高温固溶处理加790℃/680℃循环球化退火,可获得高弥散度碳化物,使CrWnMn钢的最终组织得到改善,强韧性明显提高。

关键词：复合热处理球化退火显微组织模具钢

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

重载铁路盐渍土路基中土工布使用寿命评估

引用

铁道工程学报 2015年第9期32卷 55-59页

作者：陈文化北京交通大学北京100044

研究目的:欲使土工布大规模地应用于工程,对其寿命的影响需进一步研究。针对土工布多为出厂预期寿命,缺乏工程最关心的现场使用寿命判定依据,且国内、外研究成果不多,本文通过现场和室内研究,以期确定其使用寿命并获得土工布保护技术,... 详细信息

研究目的:欲使土工布大规模地应用于工程,对其寿命的影响需进一步研究。针对土工布多为出厂预期寿命,缺乏工程最关心的现场使用寿命判定依据,且国内、外研究成果不多,本文通过现场和室内研究,以期确定其使用寿命并获得土工布保护技术,为重载铁路路基中土工布使用设计与施工提供参考。研究结论:(1)结合现场埋置土工布跟踪分析,初步估计盐渍土路基中两布一膜土工布现场使用寿命在80年以内;(2)两布一膜土工布的老化因素影响程度由大到小依次为紫外线、高拉应力、盐池水、海水等;(3)基于现场取样试验和运营线路调查分析,建议工程抽检周期为10年;(4)该研究成果可为盐渍土铁路、公路和民航工程的设计与施工提供依据。

关键词：两布一膜土工布盐渍土路基老化系数现场寿命

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Effect of Soy Isoflavone Crude Extract Supplementation on High Fat Diet-induced Insulin Resistance in Ovariectomized Rats

引用

Biomedical and Environmental Sciences 2014年第1期27卷 49-51页

作者： ZHANG Yun Bo LI Li Na ZHAO Xin Yu chen wen hua GUO Jing Jing FU Zheng Hai YANG Yang NA Xiao Lin Department of Environmental Hygiene School of Public HealthHarbin Medical University Human Resources School of Public HealthHarbin Medical University

Female Wister rats aged 8 weeks were randomly divided into sham operation group, ovariectomized （OVX） control group, and 20VX groups fed with soy isoflavone crude extract supplementation. The rats had free access to high fat diet and water for 9 weeks. No significant difference was found in body weight （BW）, total abdominal fat, food intake and food utilization rate between OVX control group and 20VX groups. However, the fasting blood glucose and blood lipid levels were significantly higher in 20VX groups than in OVX control group （P〈0.05）. Intraperitoneal glucose tolerance test （IGTI＂） showed that the area under AUC was smaller in 20VX groups than in OVX control group （P〈0.05）. These findings showed that soy isoflavone crude extract supplementation can improve glucose tolerance and prevent high fat diet-induced insulin resistance in ovariectomized rats.

关键词： Effect of Soy Isoflavone Crude Extract Supplementation on High Fat Diet-induced Insulin Resistance in Ovariectomized Rats than

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

地埋梁与横观各向同性层状地基相互作用的广义Vesic解答

引用

岩土工程学报 2018年第12期40卷 2241-2248页

作者：王雨陈文化北京交通大学土木建筑工程学院

根据横观各向同性弹性理论和传递矩阵法,考虑梁底埋深、地基的横观各向同性及成层性,推导得到基床系数的广义Vesic解答。数值算例验证了基床系数取值方法的合理性和准确性,分析了各个参数变化对基床系数取值的影响。结果表明,基床系数k... 详细信息

根据横观各向同性弹性理论和传递矩阵法,考虑梁底埋深、地基的横观各向同性及成层性,推导得到基床系数的广义Vesic解答。数值算例验证了基床系数取值方法的合理性和准确性,分析了各个参数变化对基床系数取值的影响。结果表明,基床系数k随梁底埋深h的增加而不断增大至最大值,约为地表时的2.05~2.25倍;k随着地基总厚H的增大而减小,而随横观各向同性参数r的增大而增大;当h为0或H超过100b或r为1时,本文解退化为Vesic解;土层加权平均弹性模量相同且首层土体越硬时,k值越大,且广义Vesic解用于有限长梁分析时的计算误差越小。

关键词：基床系数横观各向同性层状地基地埋梁广义Vesic解

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

地铁列车进站引起场地柱面纵向振动

引用

振动工程学报 2017年第3期30卷 442-448页

作者：张谦陈文化北京交通大学土木工程学院北京100044

地铁列车进站时引起的地层反应较为特殊与复杂,波源特性也非常丰富,为描述这种特殊的波动,探讨其振动响应规律,将列车进站制动动力行为视为对地层一种特殊的轴向激励方式,为此,建立了制动过程动力表达式,根据波函数展开法和大圆弧假定法... 详细信息

地铁列车进站时引起的地层反应较为特殊与复杂,波源特性也非常丰富,为描述这种特殊的波动,探讨其振动响应规律,将列车进站制动动力行为视为对地层一种特殊的轴向激励方式,为此,建立了制动过程动力表达式,根据波函数展开法和大圆弧假定法,对进站时引起的柱面纵向振动和振源特性进行分析,在上述动力分析中进一步考虑轨道不平顺影响。通过波动分析得到土层柱面波波场,重点研究列车在进站方向上振动响应的变化规律,并对地铁列车制动初速度、土层模量、泊松比、隧道尺寸和埋深等参数进行系统分析。结果表明:列车进站时,距离隧道10m左右,竖向振动加速度、速度达到峰值,之后迅速衰减。同时还对北京地铁宣武门车站列车进站时特殊动力响应进行现场测试分析,现场测试得到的振动规律与上述理论分析和计算结果较为接近。

关键词：地铁地基减速进站柱面纵向振动参数分析现场测试

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：