检索结果-南通市图书馆

International Journal of Mining Science and Technology 2020年第3期30卷 293-301页

作者： Jiadong Qiu Lin luo Xibing Li Diyuan Li Ying Chen yong luo Shenzhen Key Laboratory of Deep Underground Engineering Sciences and Green Energy Shenzhen UniversityShenzhen 518060China Key Laboratory of Metallogenic Prediction of Nonferrous Metals and Geological Environment Monitoring Ministry of EducationCentral South UniversityChangsha 410083China School of Resources and Safety Engineering Central South UniversityChangsha 410083China Center of Rock Mechanics and Geohazards Shaoxing UniversityShaoxing 312000China

Four groups of numerical models of Brazilian tests on rock-shotcrete interfaces were successfully conducted by PFC2D. The tensile strength and Young’s modulus of shotcrete were considered. Six different undulations of rock-shotcrete interface were set up. The influences of multiple parameters on the bearing characteristics of the rock-shotcrete interface were studied. The results showed that a better support performance can be obtained by increasing the Young’s modulus of shotcrete rather than the tensile strength of shotcrete. For different tensile strength and Young’s modulus, the increase of sawtooth height has different effects on the support performance. The failure mechanism of the rock-shotcrete interfaces was analysed in detail. The stress shielding effect and stress concentration effect caused by the shape characteristics of rock-shotcrete interface were observed. The influence of these parameters on the overall support performance should be fully considered in a reasonable support design.

关键词： Tensile strength PFC Shotcrete Fracturing behavior Rock interface

An upgraded scheme of surface physics for Antarctic ice sheet and its implementation in the WRF model

在线全文

学校读者我要写书评

暂无评论

Science Bulletin 2016年第7期61卷 576-584页

作者： Yao Yao Jianbin Huang yong luo Zongci Zhao Ministry of Education Key Laboratory for Earth System Modeling Center for Earth System Science and Joint Center for Global Change Studies Tsinghua University

Regional climate models often lack detailed description of ice sheet surface and, as a result, are limited in their capability to provide useful information for Antarctic climate research and field campaigns. In this study, an upgraded scheme of surface physics for Antarctic ice sheet(IST) is developed to improve the surface temperature simulations in Antarctica. Through stand-alone simulations, IST shows advantages over the Noah glacial module, a commonly utilized scheme in the widely used Weather Research and Forecasting(WRF) model. These improvements are mainly attributed to the incorporation of detailed snow physics and optimized surface layer parameterization, which results in better simulations of both the surface albedo in summer and the turbulent sensible heat flux in winter. When coupled with IST instead of Noah,WRF models show improved simulation of surface temperatures throughout the year. The bias and root-meansquare-error of annual mean surface temperatures are reduced from 5.7 and 6.0 to 0.2 and 2.7 K.

关键词： WRF模式南极冰盖表面物理升级方案区域气候模型表面温度温度模拟模拟显示

在线全文

学校读者我要写书评

暂无评论

微纳尺度气液传质强化油品催化加氢反应

化工进展 2024年第1期43卷 19-33页

作者：王立华蔡苏杭江文涛罗倩罗勇陈建峰北京化工大学教育部超重力工程研究中心北京100029

相比于经典的滴流床加氢技术,液相加氢技术由于其一次性投资成本和运行能耗低,受到了企业界和学术界的广泛关注。但如何进一步强化氢油相界面的传质速率来提高液相加氢效率,仍是一个重要的难题。近年来快速发展的微纳尺度气泡或液滴的... 详细信息

相比于经典的滴流床加氢技术,液相加氢技术由于其一次性投资成本和运行能耗低,受到了企业界和学术界的广泛关注。但如何进一步强化氢油相界面的传质速率来提高液相加氢效率,仍是一个重要的难题。近年来快速发展的微纳尺度气泡或液滴的气液传质强化技术有助于油品催化加氢反应。本文以微纳气泡为例,首先总结了微纳气泡特点及产生方式,简述了微纳尺度气液传质强化液相加氢过程可行性判别,回顾了微纳尺度气液传质强化在油品液相加氢工艺中的相关研究及工业应用。最后分析了微纳尺度气液传质强化在油品液相加氢中面临的挑战以及发展方向,即微纳尺度传质与本征反应的匹配、工况条件微纳气泡在反应器中的流动以及含微纳气泡混合物的气液分离等。

关键词：微纳尺度气泡加氢传递过程过程强化

在线全文

学校读者我要写书评

暂无评论

特厚煤层低位双硬顶板破断失稳规律试验研究

矿业研究与开发 2024年第1期44卷 48-53页

作者：康志鹏罗勇段昌瑞淮南矿业(集团)有限责任公司深部煤碳安全开采与环境保护全国重点实验室安徽淮南市232001 淮河能源控股集团有限责任公司、深部煤炭开采耦合灾害防控国家矿山安全监察局重点实验室安徽淮南市232001

针对特厚煤层双硬顶板放顶煤开采覆岩冲击性破断问题以及宽煤柱沿空巷道变形较大、护巷困难、需反复刷扩等问题,以麻家梁矿14202工作面为工程背景,通过物理相似模拟试验,对特厚煤层低位双硬顶板结构破断的动载效应进行研究分析。结果表... 详细信息

针对特厚煤层双硬顶板放顶煤开采覆岩冲击性破断问题以及宽煤柱沿空巷道变形较大、护巷困难、需反复刷扩等问题,以麻家梁矿14202工作面为工程背景,通过物理相似模拟试验,对特厚煤层低位双硬顶板结构破断的动载效应进行研究分析。结果表明:下位坚硬顶板自离层萌生到全部垮落工作面累计推进36m,推进60m时发生初次失稳破断,垮落厚度为4.2m,破断角为60°,顶板断裂线距煤壁5.8m,周期垮落步距约为23~25m;上位坚硬顶板自下分层垮落到完全垮落工作面累计推进23m,破断步距约为55~65m,破断角与上位坚硬顶板一致;位移监测结果显示,下位坚硬顶板与软弱夹层中下部分、上位坚硬顶板与软弱夹层上分层以及其上覆软弱岩层运动规律保持一致;双硬顶板破断失稳在采空区侧形成一定范围的应力升高区,应力峰值为23MPa,应力集中系数为1.57,应力峰值距影响范围为20m;下位坚硬顶板破断形成“短悬臂梁”结构,该结构随工作面回采动态前移形成小周期来压,上位硬顶破断形成“长砌体梁”结构,该结构破断失稳动载作用于下部“短悬臂梁”,使得其提前破断而共同作用于工作面支护体,形成大周期来压。研究结果可为特厚煤层开采多层硬顶条件下的围岩控制提供理论依据。

关键词：特厚煤层双硬顶板相似模拟破断失稳

Effect of Carburization on the Mechanical Properties of Biomedical Grade Titanium Alloys

在线全文

学校读者我要写书评

暂无评论

Journal of Bionic Engineering 2011年第1期8卷 86-89页

作者： yong luo Haibo Jiang Gang Cheng Hongtao Liu Institute of Tribology and Reliability Engineering School of Material Science and Engineering China University of Mining and Technology Xuzhou 221116 P. R. China Mechanical and Electrical Engineering Institute Xuzhou Normal University Xuzhou 221116 P. R. China

Titanium cermets were successfully synthesized on the surface of biomedical grade titanium alloys by using sequential carburization method. The mechanical properties such as hardness, fracture toughness and plasticity were measured to estimate the potential application of titanium cermets. The results show that after carburization the surface hardness of titanium cermets was 778 HV, with a significant improvement of 128% compared with that of titanium alloys. In addition, the fracture toughness of titanium cermets was 21.5 × 10^6 Pa.m^1/2, much higher than that of other ceramics. Furthermore, the analysis of the loading-unloading curve in the nanoindentation test also indicates that the plasticity of titanium cermet reached 32.1%, a relatively high value which illustrates the combination of the metal and ceramics properties. The results suggest that sequential carburization should be an efficient way to produce titanium cermets with hard surface, high toughness and plasticity.

关键词： titanium alloys hardness surfaces ceramics sequential carburization

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

全球变暖与季风

气候变化研究进展 2024年第1期20卷 118-120页

作者：赵宗慈罗勇黄建斌清华大学地球系统科学系北京100084 中国气象局国家气候中心北京100081 中国科学院大学资源环境学院北京100049

全球很多地区是季风气候,季风带来风和雨对人类生产和生活以及社会与经济发展有明显影响,因此,长期以来,季风是热门研究课题。根据有关研究,本文简述观测到的全球和区域季风变化,人类活动的影响,以及预估未来全球变暖背景下,全球和区域... 详细信息

全球很多地区是季风气候,季风带来风和雨对人类生产和生活以及社会与经济发展有明显影响,因此,长期以来,季风是热门研究课题。根据有关研究,本文简述观测到的全球和区域季风变化,人类活动的影响,以及预估未来全球变暖背景下,全球和区域的季风变化。

关键词：全球变暖热门研究课题社会与经济发展季风

基于IPA方法的湖南省乡村民宿质量提升策略研究

在线全文

学校读者我要写书评

暂无评论

湖南工业职业技术学院学报 2024年第2期24卷 37-42页

作者：罗勇长沙民政职业技术学院湖南长沙410004

随着社会需求的转变,文化旅游产业迅速发展,人们越来越追求返璞归真的农村生活,乡村民宿得以快速发展。然而,在乡村民宿不断发展的过程中也出现了不少的问题。以湖南省长沙市周边30家乡村民宿为研究样本,从916名入住顾客的体验值和期望... 详细信息

随着社会需求的转变,文化旅游产业迅速发展,人们越来越追求返璞归真的农村生活,乡村民宿得以快速发展。然而,在乡村民宿不断发展的过程中也出现了不少的问题。以湖南省长沙市周边30家乡村民宿为研究样本,从916名入住顾客的体验值和期望值出发进行IPA分析,找出促进乡村民宿发展的动力、制约乡村民宿发展的内在决定因素,以期为民宿推动乡村振兴提供更为有用的精准信息,助推乡村民宿高质量发展,实现巩固拓展脱贫攻坚成果同乡村振兴有效衔接。

关键词： IPA方法乡村民宿民宿满意度

“三硬”薄煤层沿空留巷围岩破坏特征及控制技术研究

在线全文

学校读者我要写书评

暂无评论

矿业科学学报 2024年第3期9卷 446-454页

作者：康志鹏罗勇任波段昌瑞肖殿才淮南矿业(集团)有限责任公司深部煤炭安全开采与环境保护全国重点实验室安徽淮南232001 淮河能源控股集团有限责任公司深部煤炭开采耦合灾害防控国家矿山安全监察局重点实验室安徽淮南232001

为解决薄煤层沿空留巷应力条件复杂、留巷难度大以及巷道围岩长时稳定性的难题,以陕西汇森煤业凉水井煤矿4301工作面为研究对象,采用理论分析、数值模拟、工程实践等方法,对浅埋“三硬”薄煤层沿空留巷围岩破坏特征及控制对策进行研究,... 详细信息

为解决薄煤层沿空留巷应力条件复杂、留巷难度大以及巷道围岩长时稳定性的难题,以陕西汇森煤业凉水井煤矿4301工作面为研究对象,采用理论分析、数值模拟、工程实践等方法,对浅埋“三硬”薄煤层沿空留巷围岩破坏特征及控制对策进行研究,分析巷旁支护体结构参数对于巷道稳定性的影响。结果表明:给顶板提供充足的支护强度以及合适的可缩量,是巷旁充填体整体稳定的前提;高水充填材料单轴加压下的力学行为可分为“均匀压密、弹性变形、动态失稳、劣化破坏”4个阶段;在充填体宽度增加过程中,最大应力表现为先增后减再增的趋势,在充填体1.6 m宽时出现稳定承载应力核;理论计算的切顶最佳高度为10.7 m。工程实践表明,工作面后方60 m范围无大变形和明显应力集中,围岩整体控制效果良好、结构稳定,留巷效果达到设计要求。

关键词：薄煤层沿空留巷高水材料聚能爆破

Changes in synapse quantity and growth associated protein 43 expression in the motor cortex of focal cerebral ischemic rats following catalpol treatment

同方期刊数据库博看期刊评论

在线全文

学校读者我要写书评

暂无评论

Neural Regeneration Research 2011年第18期6卷 1380-1385页

作者： Dong Wan Huifeng Zhu yong luo Peng Xie Department of Emergency First Affiliated Hospital of Chongqing Medical University Chongqing 400016 China College of Pharmaceutical Sciences & College of Chinese Medicine Southwest University Chongqing 400715 China Department of Neurology First Affiliated Hospital of Chongqing Medical University Chongqing 400016 China

The present study investigated the effects of catalpol, the main constituent of the Chinese herb Rehmannia root, on neurons following brain ischemia, A rat model of focal permanent brain ischemia was established using electrocoagulation, The rats were intrapedtoneally injected with catalpol, at a dose of 5 mg/kg, daily for 1 week, Results showed that the number of neuronal synapses in the motor cortex and growth associated protein 43 expression were increased following catalpol treatment, indicating that catalpol might contribute to neuroplasticity and ameliorate functional neurological deficits induced by cerebral ischemia.

关键词： catalpol growth-associated protein 4：3 neurological function permanent middle cerebral artery occlusion behavioral assessment neurological deficit neuroplasticity neural regeneration

Improved decadal climate prediction in the North Atlantic using EnOI-assimilated initial condition

在线全文

学校读者我要写书评

暂无评论

Science Bulletin 2017年第16期62卷 1142-1147页

作者： Min Wei Qingquan Li Xiaoge Xin Wei Zhou Zhenyu Han yong luo Zongci Zhao Ministry of Education Key Laboratory for Earth System Modeling Department of Earth System ScienceTsinghua UniversityBeijing 100084China Joint Center for Global Change Studies Beijing 100875China National Meteorological Information Center China Meteorological AdministrationBeijing 100081China Laboratory for Climate Studies National Climate CenterChina Meteorological AdministrationBeijing 100081China Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters Nanjing University of Information Science and TechnologyNanjing 210044China State Key Laboratory of Tropical Oceanography South China Sea Institute of OceanologyChinese Academy of SciencesGuangzhou 510301China

Decadal prediction experiments of Beijing Climate Center climate system model version 1.1(BCCCSM1.1) participated in Coupled Model Intercomparison Project Phase 5(CMIP5) had poor skill in extratropics of the North Atlantic, the initialization of which was done by relaxing modeled ocean temperature to the Simple Ocean Data Assimilation(SODA) reanalysis data. This study aims to improve the prediction skill of this model by using the assimilation technique in the initialization. New ocean data are firstly generated by assimilating the sea surface temperature(SST) of the Hadley Centre Sea Ice and Sea Surface Temperature(Had ISST) dataset to the ocean model of BCC-CSM1.1 via Ensemble Optimum Interpolation(EnOI). Then a suite of decadal re-forecasts launched annually over the period 1961–2005 is carried out with simulated ocean temperature restored to the assimilated ocean data.Comparisons between the re-forecasts and previous CMIP5 forecasts show that the re-forecasts are more skillful in mid-to-high latitude SST of the North Atlantic. Improved prediction skill is also found for the Atlantic multi-decadal oscillation(AMO), which is consistent with the better skill of Atlantic meridional overturning circulation(AMOC) predicted by the re-forecasts. We conclude that the EnOI assimilation generates better ocean data than the SODA reanalysis for initializing decadal climate prediction of BCC-CSM1.1 model.

关键词：气候预测模型北大西洋数据同化年代际海洋温度初始化过程气候系统模式海洋表面温度