检索结果-南通市图书馆

BGP in Nigeria--25 Years of Staying true to Our Original Aspirations Through Thick and Thin

在线全文

学校读者我要写书评

暂无评论

China Oil & Gas 2024年第1期31卷 52-56页

作者： Yang Tao Bureau of Geophysical Prospecting INC

Aspan of twenty-five years,for a company,constitutes a engthy and eventful journey.Twenty-five years ago,a group of oil professionals from the Bureau of Geophysical Prospecting INC (hereinafter referred to as BGP),set foot on the land of Nigeria and embarked on a legendary journey.This is a narrative of resilience,commitment,and heartfelt passion,an inspiring saga that touches the soul.

关键词： constitute true Geophysical

All Voices Should Be Heard and Heeded in a true Democracy

在线全文

学校读者我要写书评

暂无评论

China Today 2024年第5期73卷 46-49页

作者： ZHANG HUI 不详

For all its different forms,democracy is expected to promote people’s well-being,instead of being weaponized to justify hegemony,as democracy is also a principle of global governance.

关键词： true Voice Should

An anisotropic constitutive model of geomaterials based on true triaxial testing and its application

维普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

Journal of Central South University 2017年第6期24卷 1430-1442页

作者：张坤勇 Frederick Nai Charkley Key Laboratory of Ministry of Education for Geomechanics and Embankment Engineering Nanjing 210098China Geotechnical Research Institute Hohai UniversityNanjing 210098China

Series of testing on coarse grained soils were carried out with a true triaxial testing apparatus. The loads were applied from the major principal and minor principal directions, respectively, to simulate the construction and water impounding process of a rock fill dam. The stress and strain relationships induced by the different loading methods were investigated. A remarkable stress-induced anisotropy under complex stress state was observed. Contrary to popular assumptions in traditional numerical analysis and constitutive models, it was found that different elastic modulus and Poisson ratio exist in different principal directions in rock fill dams. From the testing results, an anisotropic constitutive model based on Duncan-Chang nonlinear model is presented to overcome the limitations of axi-symmetric assumptions in conventional triaxial experiments and constitutive models. Both models were then applied in FEM analysis of an under-construction earth core high rock soil filled dam with the focus on hydraulic fracturing. The study reveals the major biases that exist when numerical analysis and constitutive models do not give serious consideration to the intermediate principal stress and anisotropy effects in soil rock built structures.

关键词： true triaxial test stress induced anisotropy constitutive model complex stress state finite element method (FEM)

Rockburst characteristics of several hard brittle rocks:A true triaxial experimental study

在线全文

学校读者我要写书评

暂无评论

Journal of Rock Mechanics and Geotechnical Engineering 2020年第2期12卷 279-296页

作者： Shaobin Zhai Guoshao Su Shunde Yin Bin Zhao Liubin Yan Key Laboratory of Disaster Prevention and Structural Safety of Ministry of Education School of Civil and Architecture EngineeringGuangxi UniversityNanning530004China Department of Civil and Environmental Engineering University of WaterlooWaterlooON N2L 3G1Canada State Key Laboratory of Geohazard Prevention and Geoenvironment Protection Chengdu University of TechnologyChengdu610059China

Rockburst is a typical rock failure which frequently threatens both human life and construction equipment during highly stressed underground excavation.Rock lithology is a control factor of rockburst.In this paper,rockburst tests were conducted on rectangular prismatic specimens of six types of intact hard brittle rocks,i.***.granodiorite,granite,marble,basalt,sandstone and limestone,under one-free-face true triaxial loading conditions.With the use of high-speed cameras,an acoustic emission(AE)system and a scanning electron microscope(SEM),rockburst of different rocks was investigated.The results show that the strainbursts of granodiorite,granite and marble were accompanied by tensile splitting near the free face,and consequently were relatively strong with a large amount of fragment ejection and kinetic energy release.For basalt,sandstone and limestone,failure was primarily dominated by shear rupture.The strainbursts of basalt and sandstone were relatively small with minor fragment ejection and kinetic energy release;while no burst failure occurred on limestone due to its relatively low peak strength.Rock strength,fracturing and fragmentation characteristics,and failure modes of different rocks can significantly affect rockburst proneness and magnitude.The AE evolution coupled with SEM analysis reveals that the differences in the inhe rent microstructures and fracture evolution under loading are the primary factors accounting for different rockbursts in various rock types.

关键词： Rockburst Strainburst Hard brittle rocks true triaxial test Acoustic emission(AE)

Conceptual design,data model and key techniques of“3D Assistant”

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 692-698页

作者： LI Qing-yuan1, ZHANG Xuan2, JIN Yang2, ZHOU Hui3, WANG Qian-jin3,WEI Zhan-yin1 1. Key Laboratory of Geo-Informatics, Chinese Academy of Surveying and Mapping, Beijing 100830, China 2. School of Geo-Science and Surveying Engineering, China University of Mining and Technology, Beijing 100083, China 3. School of Geomatics, Liaoning Technical University, Fuxin 123000, China Key Laboratory of Geo-Informatics Chinese Academy of Surveying and Mapping Beijing 100830 China School of Geo-Science and Surveying Engineering China University of Mining and Technology Beijing 100083 China School of Geomatics Liaoning Technical University Fuxin 123000 China

Conceptual design, data model and key techniques of "Geo-engineer 3D assistant", an underground 3D GIS oriented to geology and mine application, were discussed. In particular, the importance of high-order smoothing triangular pieces to surface's fine expression in geological modeling was emphasized. The contour mode is the most favorite mode of the three modes about surface expression: DEM, TIN and contour. Topology in underground 3D modeling with CAGD was compared. From the view of boundary and coboundary, which is soul of IS 19107 (Geographic information spatial schema), 3D underground topology was re-examined.

关键词： 3D assistant true 3D GIS fine expression of surface contour mode 3D topology

The spatial scaling effect of continuous canopy Leaves Area Index retrieved by remote sensing

在线全文

学校读者我要写书评

暂无评论

Science China Earth Sciences 2009年第3期52卷 393-401页

作者： XU XiRu FAN WenJie TAO Xin Institute of Remote Sensing and GIS Peking UniversityBeijing 100871China

Leave Area Index (LAI) is one of the most basic parameters to describe the geometric structure of plant canopies. It is also important input data for climatic model and interaction model between Earth surface and atmosphere, and some other things. The spatial scaling of retrieved LAI has been widely studied in recent years. Based on the new canopy reflectance model, the mechanism of the scaling effect of con- tinuous canopy Leaf Area Index is studied, and the scaling transform formula among different scales is found. Both the numerical simulation and the field validation show that the scale transform formula is reliable.

关键词： spatial scaling effect remotely sensed LAI the true LAI the reflectance model of continuous canopy

A new approach on necking constitutive relationships of ductile materials at elevated temperatures

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2016年第6期29卷 1626-1634页

作者： Yao Di Cai Lixun Bao Chen School of Mechanics and Engineering Southwest Jiaotong University

A new method is presented to determine the full-range, uniaxial constitutive relationship of materials by tensile tests on funnel specimens with small curvature radius and finite element analysis(FEA). An iteration method using FEA APDL(ANSYS parametric design language) programming has been developed to approach the necking constitutive relationship of materials. Test results from SAE 304 stainless steel at room temperature show that simulated load vs displacement curve,diameter at funnel root vs displacement curve, and funnel deformation contours are close to modeled results. Due to this new method, full-range constitutive relationships and true stress and effective true strain at failure are found for 316 L stainless steel, TA17 titanium alloy and A508-III stainless steel at room temperature, and 316 L stainless steel at various elevated temperatures.

关键词： Ductile material Elevated temperatures Finite element aided testing(FAT) method Fracture stress-strain true stress-strain

Pre-cecal phosphorus digestibility for corn, wheat, soybean meal,and corn gluten meal in growing Japanese quails from 28 to 32 d of age

在线全文

学校读者我要写书评

暂无评论

Animal Nutrition 2019年第2期5卷 148-151页

作者： Mahmoud Ghazaghi Ahmad Hassanabadi Mehran Mehri Department of Animal Science Faculty of AgricultureFerdowsi University of MashhadMshhad 91775-1163Iran Department of Animal Sciences University of ZabolZabol 98661-5538Iran

The optimization of dietary phosphorus(P) depends on precise details of the P availability in feed ingredients to avoid excess or deficient P in a mixed diet. This study was carried out to measure the apparent ileal digestibility of P for corn, wheat, soybean meal, and corn gluten meal in growing Japanese quails from 28 to 32 d posthatch, A total of 400 quail chicks were randomly distributed across 5 treatments with 4 replicates and 20 birds in each floor pen. The P-free diet(PFD) was formulated based on cornstarch to measure the basal endogenous P losses(EPL). Digestibility coefficients were determined by ileal digesta sampling using TiO2 as an indigestible marker. The EPL was estimated at 384 mg/kg DMI. The apparent ileal P digestibility(AIPD) for corn, soybean meal, wheat, and corn gluten meal were determined to be 0.***.0.53, 0.38, and 0.78, respectively. The corresponding values for true ileal P digestibility(TIPD) were 0.***.0.61, 0.50, and 0.83, respectively. The t-test analysis showed that the difference of AIPD and TIPD values for corn(P = 0.031) and wheat(P = 0.015) were statistically significant, however, no significant differences were observed for corn gluten meal(P = 0.318) and soybean meal(P = 0.104). In conclusion, the correction of AIPD coefficients for EPL in low-P ingredients such as corn and wheat may be much more important than that in high-P feedstuffs such as corn gluten meal and soybean meal in growing quails.

关键词： Quail chicks Phosphorus true digestibility Basal endogenous losses P-free diet

true Democracy Shown in Democratic System with Chinese Characteristics

在线全文

学校读者我要写书评

暂无评论

Contemporary World 2023年第2期 44-48页

作者： Jean-Christophe Iseux the UK based Institute for East-West Strategic Studies Emmanuel College University of Cambridge

Alexis de Tocqueville wrote De la Democratie en Amerique a brilliant analysis of the NorthAmerican democratic system, and in the process conducted a thorough critique of the European democratic system of his time. I w... 详细信息

关键词： true Demo brilliant