检索结果-南通市图书馆

Experimental study of dynamic mechanical properties of reactive powder concrete under high-strain-rate impacts

Science china(Technological Sciences) 2010年第9期53卷 2435-2449页

作者： ju yang1,2.liu hongbin1,sheng guohua1,3 & wang huijie1 1 state key laboratory of coal resources and safe mining,beijing key laboratory of fracture and damage mechanics of rocks and concrete,china university of mining and technology,beijing 100083,china 2 Department of Mechanical and Manufacturing Engineering,university of Calgary,2500 university Drive,AB T2N 1N4,Canada 3 School of resources and Civil Engineering,Northeastern university,Shenyang 110004,china 1. state key laboratory of coal resources and safe mining Beijing Key Laboratory of Fracture and Damage Mechanics of Rocks and Concrete China University of Mining and Technology Beijing 100083 China2. Department of Mechanical and Manufacturing Engineering University of Calgary 2500 University Drive AB T2N 1N4 Calgary Canada3. School of Resources and Civil Engineering Northeastern University Shenyang 110004 China

The dynamic mechanical properties of reactive powder concrete subjected to compressive impacts with high strain rates ranging from 10 to 1.1×102 s-1 were investigated by means of SHPB (split-Hopkinson-pressure-bar) tests of the cylindrical specimens with five different steel fiber volumetric *** properties of wave stress transmission,failure,strength,and energy consumption of RPC with varied fiber volumes and impact strain rates were *** influences of impact strain rates and fiber volumes on those properties were characterized as *** general forms of the dynamic stress-strain relationships of RPC were modeled based on the experimental *** investigations indicate that for the plain RPC the stress response is greater than the strain response,showing strong brittle *** RPC with a certain volume of fibers sustains higher strain rate impact and exhibits better deformability as compared with the plain *** a constant fiber fraction,the peak compressive strength,corresponding peak strain and the residual strain of the fiber-reinforced RPC rise by varying amounts when the impact strain rate increases,with the residual strain demonstrating the greatest *** the fiber content makes trivial contribution to improving the residual deformability of RPC when the impact strain rate is *** tests also show that the fiber content affects the peak compressive strength and the peak deformability of RPC in a different *** a constant impact strain rate and the fiber fraction less than 1.75%,the peak compressive strength rises with an increasing fiber *** peak compressive strength tends to decrease as the fiber volume exceeds 1.75%.The corresponding peak strain,however,incessantly rises with the increasing fiber *** total energy Edisp that RPC consumed during the period from the beginning of impacts to the time of residual strains elevates with the fiber volume increment as long as the fiber fraction

关键词： impact reactive powder concrete (RPC) high strain rate dynamic strength energy consumption dynamic stress-strain response

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

laboratory investigation on mechanisms of stress wave propagations in porous media

引用

Science china(Technological Sciences) 2009年第5期52卷 1374-1389页

作者： ju yang yang YongMing MAO YanZhe liu hongbin wang huijie state key laboratory of coal resources and safe mining China University of Mining&TechnologyBeijing 100083China Department of Mechanical and Manufacturing Engineering The University of Calgary2500 University Drive NW CalgaryAB T2N 1N4Canada university of Illinois at Urbana-Champaign 1110 West Green StreetUrbanaIL 61801USA beijing Tongchen Design of Architecture Ltd Beijing 100044China

A number of porous models having the similar statistical characteristics of pores and physical properties with natural sandstones have been produced using reactive powder concrete(RPC) and ***-Hopkinson-Pressure-Bar tests and CT scans have been carried out on the models with the various porosities to probe the performance of wave propagations and the responses of pores and the matrix during wave *** is shown that porosities significantly influence wave *** an identical impact strain rate,the greater the porosity is,the larger the amplitude of the reflected wave appears,the more the peak in the reflected wave presents,and the smaller the amplitude of the trans-mitted wave turns out.A single peak emerges in the reflected wave when the porosity falls down to 5%.The larger the impact strain rate,the much remarkable the *** energy-dissipated ratio of porous models,i.e.,WJ /WI,linearly increases with the increment of *** ratio is sensitive to the impact strain *** in the performance of wave propagations and energy dissipation result from the varied mechanisms that pores response to *** the porosity less than 10%,the mechanism appears to be a process fracturing the matrix to generate new surfaces or *** has primarily been dissipated in creating new surfaces or *** apparent pore deformation takes *** impact strain rate takes little effect on pore *** the porosity of 15% or more,the mechanism works depending on the impact strain *** a low impact strain rate applies,the mechanism still appears to crack the matrix to generate surfaces or pores,but the amount is lower as compared to the case with a low *** a large impact stain rate applies,the mechanism combines both fracturing the matrix and deforming the pores,with the deforming pores *** vast majority of energy has been dissipated to deform *** high porosity and impact strain rate c

关键词： stress wave porous media propagation mechanism sandstones pores CT scan

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

Toughness and characterization of reactive powder concrete with ultra-high strength

引用

Science china(Technological Sciences) 2009年第4期52卷 1000-1018页

作者： yang ju hongbin liu Jian Chen YuDan Jia PeiHuo Peng state key laboratory of coal resources and safe mining China University of Mining & Technology Beijing 100083 China Department of Mechanical & Manufacturing Engineering The University of Calgary 2500 University Drive NW Calgary AB T2N 1N4 Canada The university of Illinois at Urbana-Champaign 1110 West Green Street Urbana IL 61801 USA Building Design Division China Nuclear Power Engineering Co. Ltd Beijing 100840 China School of Civil Engineering University of Nottingham University Park Nottingham NG7 2RD UK

A number of three-point bending and fracture tests of 200 MPa-level reactive powder concrete (RPC) with the various fiber contents have been conducted to probe the nature and characteristics of toughness of RPC200. The contribution of the embedded fibers to improving the crack-resistant capacity, energy absorption capacity and toughness with various deformation mechanisms has been analyzed. Taking account of that the first-crack deformation, peak-load deformation and their improvement varied with the fiber contents and that the deformation mechanism affected differently the performance at the first crack and the peak load, we took the peak-load deformation of plain RPC200 as the reference deformation to measure the toughness of fibered RPC200. Two toughness indices T 2(n−1)(n) and FT 2(n−1)(n) have been formulated based on P-δ responses and P-CMOD responses. The indices quantify the toughness of RPC200 with the various deformation mechanisms relative to perfectly elastoplastic materials by setting the toughness level 2(n−1) as the initial reference. It is shown that the toughness index T 2(n−1)(n) reflects the function of fibers to improve the toughness of RPC with the deformation throughout specimens, but overestimates the contribution to enhancing the toughness in post-peak periods. It underestimates, on other hands, the contribution to improving the toughness in the period from the first crack to the peak load. In contrast, the toughness index FT 2(n−1)(n) properly presents the capability that fibers absorb energy and constrain crack propagation in the matrix when the deformation is concentrated on the open crack. The proposed index unveils the contribution of fibers to toughening RPC200 both in the period from the first-crack to the peak load and in the period of post peak. This characterization method not only reveals the nature of toughness but also levels the toughness of RPC200. I

关键词： reactive powder concrete toughness characterization index deformation mechanism flexure fracture

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

Mechanically flexible V_(3)S_(4)@carbon composite fiber as a high-capacity and fast-charging anode for sodium-ion capacitors

引用

稀有金属:英文版 2023年第8期42卷 2633-2642页

作者： Zhi-Fei Mao Xiao-jun Shi Tao-Qiu Zhang Peng-ju Liang Rui wang jun Jin Bei-Bei He Yan-sheng Gong Qiang wang Xi-Li Tong Huan-Wen wang Faculty of Material Science and Chemistry China University of GeosciencesWuhan 430074China Engineering laboratory of Chemical resources Utilization in South Xinjiang of XPCC Department of Chemistry and Chemical EngineeringCollege of LifeTarim UniversityAlar 843300China state key laboratory of coal Conversion Institute of Coal ChemistryChinese Academy of SciencesTaiyuan 030001China

Hybrid Na-ion capacitors(NICs)have received considerable interests owing to their low-cost,high-safety,and rapidly charging energy-storage *** NICs are composed of a capacitor-type cathode and a battery-type *** major challenge for NICs is to search for suitable electrode materials to overcome the sluggish diffusion of Na^(+)in the ***,ultrafine vanadium sulfide is encapsulated in carbon fiber(V_(3)S_(4)@CNF)as a self-supported electrode by electrospinning and in situ *** carbon cladding and one-dimensional(ID)nanofiber network-like structure could alleviate the volume expansion of V_(3)S_(4)during Na^(+)de-/intercalation ***,the V_(3)S_(4)@CNF anode exhibited a pseudocapacitive sodium storage in terms of large Na^(+)-storage capacity(476 mAh·g^(-1)at 0.1A·g^(-1)),high-rate capability(290 mAh·g^(-1)at 20.0 A·g^(-1))and excellent cycling stability(95%capacity retention for1500 cycles at 2.0 A·g^(-1))in Na *** employing V_(3)S_(4)@CNF as the anode and the activated carbon(AC)cathode,the as-assembled NICs could deliver a high energy density of 110 Wh·kg^(-1)at a power density of200 W·kg^(-1).Even at a high power of 10,000 W·kg^(-1),the specific energy is still up to 42 Wh·kg^(-1).

关键词： Electrospinning Na-ion capacitor(NIC) Nanofibers Vanadium sulfide Fast-charging

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

重庆市北碚城区气溶胶中有机碳和元素碳的污染特征

引用

环境科学 2018年第8期39卷 3502-3510页

作者：彭小乐郝庆菊温天雪吉东生刘子锐王跃思陈建博江长胜西南大学资源环境学院三峡库区生态环境教育部重点实验室重庆400715 中国科学院大气物理研究所大气边界层物理和大气化学国家重点实验室北京100029

为了研究重庆市北碚城区大气碳质气溶胶组分的污染特征,于2014年3月~2015年2月采用安德森采样器采集大气颗粒物样品,用DRI Model 2001 A热光碳分析仪测定其中有机碳(OC)和元素碳(EC)的质量浓度.结果表明,北碚城区PM_(2.1)和PM_(9.0)中OC... 详细信息

为了研究重庆市北碚城区大气碳质气溶胶组分的污染特征,于2014年3月~2015年2月采用安德森采样器采集大气颗粒物样品,用DRI Model 2001 A热光碳分析仪测定其中有机碳(OC)和元素碳(EC)的质量浓度.结果表明,北碚城区PM_(2.1)和PM_(9.0)中OC和EC的年平均浓度分别为(16.3±7.6)、(1.8±0.7)和(25.0±9.7)、(3.2±1.3)μg·m-3.在PM_(2.1)中,OC和EC均呈现出冬春季大于夏秋季的季节变化特征,而PM_(9.0)中OC呈现出夏春季大于冬秋季,EC呈现出冬春季大于夏秋季的季节变化特征.对全年OC和EC的粒径进行分析,发现OC在整个粒径上呈现"双峰型"分布,其中细粒子段峰值位于0.43~0.65μm粒径段,粗粒子段峰值位于4.7~5.8μm粒径段;EC呈现出"三峰型"分布,其中细粒子段峰值位于0.43~0.65μm粒径段,粗粒子段峰值位于4.7~5.8μm粒径段,同时2.1~3.3μm粒径段也出现一个明显峰值.对OC和EC进行相关性分析并对PM_(2.1)中的SOC进行估算,发现北碚城区全年SOC浓度为(6.3±5.9)μg·m-3,占全年OC的33.5%±22.6%,且OC和EC显著相关.最后对北碚城区大气气溶胶的污染来源进行分析,发现污染主要来源于汽油车尾气、生物质燃烧和燃煤排放.

关键词：有机碳(OC) 元素碳(EC) 粒径北碚大气气溶胶

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

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

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：