检索结果-南通市图书馆

The Compatibility of Polycarboxylate-Type Superplasticizers with Cement

在线全文

学校读者我要写书评

暂无评论

Journal of Wuhan University of technology(Materials Science) 2005年第3期20卷 95-98页

作者：李崇智 Department of Civil Engineering Beijing Institute of Civil Engineering and Architecture

Four polycarboxylate- type （ PC ） superplasticizers of different functional groups were used ; their dispersing and retaining behaviors were analyzed through ZETA potential measurement, mini-slump test of cement paste and performance test of concrete. The experimental results show that the dispersing and flow-retaining ability of PC was determined by two factors of anionic groups and nonionic groups ： the density of anionic groups - COO^- or - SO3^- acted on the electronic repulsive force. and the length and proportion of nonionic graft groups of PEO in PC chemical stracture affected the steric effect. The compatibility between PC superplasticizers and cement mainly depended on the type of PEO groups ; furtlwrmore, adding mineral powders is good to the compatibility for high performance concretes （ HPCs ）.

关键词： PC superplasticizers cement compatibility

Quantitative analysis on soil erosion based on 3S technology

在线全文

学校读者我要写书评

暂无评论

中国有色金属学会会刊：英文版 2005年第S1期15卷 82-85页

作者： JING Hai-tao~1, XIE Hong-quan~(2. 3), FU Mei-chen~2. FENG Zhong-ke~4 (1. Xuzhou Normal University, Xuzhou 2.1009, china 2. china University of mining and technology(beijing Campus), beijing 100083, china 3. Hebei Polytechnic University, Tangshan 063009, china 4. beijing Forestry University, beijing 100083, china Xuzhou Normal Univ Xuzhou 221009 Peoples R China china Univ Min & Technol Beijing 100083 Peoples R China Hebei Polytech Univ Tangshan 063009 Peoples R China beijing Forestry Univ Beijing 100083 Peoples R China

The quantitative analysis on soil erosion is very significant for macro-decision of soil loss, for quick control of natural disasters and for system of periodical report. Based on the research of 3S(GPS, GIS and RS), the special information can be obtained by GPS or RS. Digital elevation model can be formed by GIS software, and at the same time, we can get some vector graph, such as landuse, vegetation type and soil type. Then the soil erosion of research area was calculated by USLE. The methods and techniques were discussed, including how to carve up polygons, how to capture the values of factors and how to differentiate the erosion intensity.

关键词： soil erosion USLE GPS GIS RS

Resistance to chemical attack of bittern-resisting cement in high-bittern environment

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2005年第5期 87-93页

作者： Yunbing Hou, Bingwen Wang, Yu chen, Botao Zhang, and Lin Yu School of Resource & Safety Engineering, china University of {2. & technology (beijing), beijing 100083, china

A new kind of bittern-resisting cement (BRC) was introduced. This material is based on the ternary cementitious system of clinker containing C4A3 S phase, high-activity ground granulated blast-furnace slag (GGBFS) and fly ash (FA). The hydration proc- ess and the hydrated products of BRC were studied by means of XRD, TG-DTA and SEM, and the resistance to chemical attack of BRC in high-bittern environment was also examined. The corrosion experiment in seven kinds of brines proved that BRC exhibits an excellent resistance to chemical attack of bittern. The corrosion resistance factors were calculated and all of them were greater than 0.96. It showed that BRC totally controls the cement-based material corrosion in brines from four aspects: (1) making full use of the dominant complementation effect of mineral materials; (2. diminishing the hydrated products easy to be attacked; (3) improving the microstructure of hardened cement mortar; (4) degrading the chemical attack of bittern.

关键词： bittern-resisting cement ternary cementitious system high-activity mineral materials resistance to chemical attack bit- tern corrosion resistance factor corrosion mechanism

Abnormal gradient microstructure in Cr_3C_2.based cemented carbide

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Central South University of technology 2001年第4期8卷 224-227页

作者： ZHANG Li 1,chen Shu 2.(1. Powder Metallurgy Factory, Central South University, Changsha 410083, china 2. Changsha Research Institute of {2. and Metallurgy, Changsha 410012. china) 1. Powder Metallurgy Factory Central South University 410083 Changsha China 2. Changsha Research Institute of mining and Metallurgy 410012 Changsha China

With OLYMPUS PMG3 metallograph, an abnormal three-layer gradient structure, i. e. coarse grain zone, binder enrichment zone and normal structure zone from surface to inner, was observed in Cr3C2.based cemented carbide. In the binder enrichment zone, three different shapes of anomalous coarse carbides were observed. It is shown that the transverse rupture strength can be raised remarkably, up 2..7%from the alloy with abnormal gradient structure by removing the abnormal gradient structure. The results suggested that the abnormal gradient structure in the surface, especially the anomalous coarse carbides in the binder enrichment zone is the main reason for the lower strength

关键词： Cr3C2.based cermet cemented carbide gradient structure microstructure

Real-time emergency route generating algorithm in tunnel

在线全文

学校读者我要写书评

暂无评论

中国有色金属学会会刊：英文版 2011年第S3期21卷 637-641页

作者： FANG Yuan-min1, chen Jie1, AI Chun-long2. ZHANG Chun-liang2. ZHOU Shi-yong2. FU Xia-jiang2. GU De-mao2.1. Faculty of Land Resource Engineering, Kunming University of Science and technology, Kunming 650093,{2. 2. Dahongshan Copper Ore Mine of Yuxi mining Co. Ltd., Xinping 653405,{2. [a] Faculty of Land Resource Engineering Kunming University of Science and Technology Kunming 650093 China [b] Dahongshan Copper Ore Mine of Yuxi mining Co. Ltd. Xinping 653405 China

As part of the digital mine system, a real time emergency route generating algorithm for a large scale metal mine is studied. The tunnel is abstracted and mathematically described by the center line model. A series of definitions are made and the center lines are regularized. In order to improve the quality of the final routes, a center line dataset preprocessing is done according to the factors including the slope threshold and the tunnel closed state information, etc. While in preprocessing, the mineshaft and shaft with the steep slope are excluded implicitly. The interface is preserved for point-like objects (e.g. blowers), directions (e.g. wind direction of blowers) and so on. The final path finding algorithm is optimized by the filter operation that the calculation is only performed at the endpoints and hub points, which can further reduce computing data amount. In our experiment, 3 368 nodes out of 2. 401 nodes are selected as key nodes, therefore, the data processing amount of the algorithm is reduced to 1/7 and the routes can be found in real time. The algorithm is implemented and integrated into the final digital mine system.

关键词： digital mine tunnel path finding problem DIJKSTRA algorithm adjacency list

Characterization of diamond MWCNTs composite fiber synthesized under high pressure and high temperature

在线全文

学校读者我要写书评

暂无评论

金刚石与磨料磨具工程 2008年第S1期28卷 62-67页

作者： Deng Fuming~(1,2. Lu Xuejun~(1,3) Liu Ruiping~1 Xu Guojun~3 chen Quwu~1 Li Wenzhu~2.(1.Department of Materials Science and Engineering,china University of {2. and technology,beijing Campus,beijing 100083,china) (2.Department of Physics,Zhejiang University,Hangzhou 31002.,china) (3.beijing Institute of Electro-machining,beijing 100083,china)

A regrown composite fiber was synthesized during the sintering of diamond under high pressure 5.8 GPa and high temperature 1500℃for 1 min,using 3wt%MWCNTs as *** observation of the fiber after alkali and acid treatment revealed that the outer layer of the fiber is composed of nano-polycrystalline ***,XPS,XRD and Raman spectrum analysis further identified that the fiber is composed of MWCNTs in the inner part and nano-polycrystalline diamond in the out *** is proposed that the untransformed MWCNTs may act as a template for the regrown outer layer of nano diamond fiber under high pressure and high temperature.

关键词： Mullti-walled carbon nanotubes(MWCNTs) Nano-polycrystalline diamond fiber High pressure/high temperature(HP-HT) Sintering

Microstructure and properties of the sintered diamond reinforced by diamond-MWCNTs composite fibers

在线全文

学校读者我要写书评

暂无评论

金刚石与磨料磨具工程 2008年第S1期28卷 56-61页

作者： Deng Fuming~(1,2. Lu Xuejun~(1,3) Liu Ruiping~1 Xu Guojun~3 chen Quwu~1 Li Wenzhu~2.(1.Department of Materials Science and Engineering,china University of {2. and technology,beijing Campus,beijing,100083,china) (2.Department of Physics,Zhejiang University,Hangzhou,31002.,china) (3.beijing Institute of Electro-machining,beijing,100083,china)

A new type of sintered diamond reinforced by diamond MWCNTs composite fibers which were randomly orientated and even distributed in the diamond matrix was synthesized by using 3wt%mullti-walled carbon nanotubes（MWCNTs） as starting additive under high pressure of 5.8 GPa at temperature of 1500℃for 1 min.A special polycrystalline diamond structure of direct bonding of both diamond to diamond and diamond to diamond-MWCNTs composite fiber was *** testing results show that it possesses not only high hardness（49～52.GPa） and Young’s modulus（878 GPa） but also high bending strength（132.～1540 GPa） and fracture toughness(9.0～9.2.MPa·m1/2./sup>) as it was theoretically *** high performances of the composite were contributed by the fiber strengthening effect and the special structure which can offer more extensive diamond to diamond bonding.

关键词： mullti-walled carbon nanotubes(MWCNTs) nano-polycrystalline diamond fiber high pressure high temperature(HP-HT) properties

Spatio-temporal model for soil characteristic of reclamation land

在线全文

学校读者我要写书评

暂无评论

中国有色金属学会会刊：英文版 2005年第S1期15卷 45-48页

作者： chen Qiu-ji~(1, 2., HU Zhen-qi~1, FU Mei-chen~3, XIE Hong-quan~4, HAO Hai-fu~5 (1.{2. University of mining and technology(beijing Campus), beijing 100083,{2. 2. Henan Polytechnic University, Jiaozuo 454000,{2. 3.{2. University of Geosciences, beijing 100083,{2. 4. Hebei Polytechnic University, Tangshan 063009,{2. 5.{2. Railway Shiqiju Group Corporation, Taiyuan 030600,{2.) china Univ Min & Technol Beijing 100083 Peoples R China Henen Polytech Univ Jiaozuo 45400 Peoples R China china Univ Geosci Beijing 100083 Peoples R China Hebei Polytech Univ Tangshan 063009 Peoples R China china Railway Shiqiju Grp Corp Taiyuan 030600 Peoples R China

The development of spatio-temporal data model is introduced. According to the soil characteristic of reclamation land, we adopt the base state with amendments model of multi-layer raster to organize the spatio-temporal data, using the combined data structure on linear quadtree and linear octree to code. The advantage of this model is that it can easily obtain the information of certain layer and integratedly analyze the data with other methods. Then, the methods of obtain and analyses are introduced. The method can provide a tool for the research of the soil characteristic change and spatial distribution in reclamation land.

关键词： reclamation soil spatio-temporal data model linear quad-tree linear octree

FRACTAL GEOMETRY AND FRACTURE OF ROCK

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica Sinica 1988年第3期4卷 255-264页

作者： Xie Heping chen Zhida china Institute of {2. & technology 1. china Institute of mining & {2. China

The irregular and rough profile of fracture surfaces of rock can be regarded as havingself-similarity statistically. The authors apply a new geometry----fractal geometry to describe thisirregularity. Fractal models of the transgranular fracture and the combined intergranular andtransgranular fracture are established. The fractal character of fracture surface of rock is examined byelectron scanning and optical fractographic analyses. Finally, the relation between fractal dimensionand macromechanics quantities of rock fracture is obtained.

关键词： fractal dimension fractal model transgranular brittle fracture intergranular brittle fracture rock fractography