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Application of the quadrilateral area coordinate method:a new element for laminated composite plate bending problems 被引量:6
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作者 Song Cen Xiangrong Fu +2 位作者 Yuqiu Long Hongguang Li Zhenhan Yao 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2007年第5期561-575,共15页
Recently, some new quadrilateral finite elements were successfully developed by the Quadrilateral Area Coordinate (QAC) method. Compared with those traditional models using isoparametric coordinates, these new model... Recently, some new quadrilateral finite elements were successfully developed by the Quadrilateral Area Coordinate (QAC) method. Compared with those traditional models using isoparametric coordinates, these new models are less sensitive to mesh distortion. In this paper, a new displacement-based, 4-node 20-DOF (5-DOF per node) quadrilateral bending element based on the first-order shear deformation theory for analysis of arbitrary laminated composite plates is presented. Its bending part is based on the element AC-MQ4, a recent-developed high-performance Mindlin-Reissner plate element formulated by QAC method and the generalized conforming condition method; and its in-plane displacement fields are interpolated by bilinear shape functions in isoparametric coordinates. Furthermore, the hybrid post-rocessing procedure, which was firstly proposed by the authors, is employed again to improve the stress solutions, especially for the transverse shear stresses. The resulting element, denoted as AC-MQ4-LC, exhibits excellent performance in all linear static and dynamic numerical examples. It demonstrates again that the QAC method, the generalized conforming condition method, and the hybrid post-processing procedure are efficient tools for developing simple, effective and reliable finite element models. 展开更多
关键词 Quadrilateral area Coordinate (QAC) Finite element Laminated composite plate First-order shear deformation theory (FSDT) Hybrid post-processing procedure
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Quantitative analysis of biotechnical reinforcement for a steep slope consisting of composite coal-gangue-soil medium adjacent to a mined-out area 被引量:3
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作者 Xingping Lai Mowen Xie +1 位作者 Fenhua Ren Meifeng Cai 《Journal of University of Science and Technology Beijing》 CSCD 2005年第6期489-494,共6页
The engineering and geological characteristics of a steep slope consisting of coal gangue, rock and soil medium in Huating coal mine have been comprehensively investigated. Owing to humid weather, heavy rainfall, vege... The engineering and geological characteristics of a steep slope consisting of coal gangue, rock and soil medium in Huating coal mine have been comprehensively investigated. Owing to humid weather, heavy rainfall, vegetation and porous characteristics of the soil and rock mass, the steep slope will be destabilized and induce mud-rock flow or derive hazard easily. Firstly, based on the classical slope reinforcement theory, some regularity between the shear and displacement in the destabilized zone of the slope with or without root strength contribution is presented. Then, based on the experimental and statistical analysis of root strength, hydrological characteristics and stability status, etc., some possible biotechnical techniques for reinforcement of the steep slope have been suggested. These methods are important for quantitative analysis of destabilization of the slope and design of the biotechnical reinforcement. 展开更多
关键词 mined-out area coal-gangue-soil composite medium steep slope root-soil effect biotechnical reinforcement
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Study on the crustal stress fi eld of the Tengchong volcanic area using composite focal mechanism method 被引量:3
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作者 Sheng Shu-zhong Wan Yong-ge +4 位作者 Jiang Chang-sheng Wang Xiao-shan Liang Shan-shan Xiao Gen-ru Hu Xiao-hui 《Applied Geophysics》 SCIE CSCD 2021年第2期238-251,274,共15页
We calculated the crustal stress field using the composite focal mechanism method based on the P-wave initial motion polarity data of the Tengchong volcanic area from January 2011 to April 2019 obtained from the Bulle... We calculated the crustal stress field using the composite focal mechanism method based on the P-wave initial motion polarity data of the Tengchong volcanic area from January 2011 to April 2019 obtained from the Bulletin of Seismological Observations of Chinese stations.The magnitude range of earthquakes used in this study is 0–4,and their magnitudes are mainly approximately 1.0.To investigate the infl uence of the source location on the stress fi eld and obtain reliable stress fi elds of the study area,we applied the double-diff erence algorithm to relocate the seismic events,obtaining more accurate and reliable relative positions of seismic events with a clearer seismic belt.On the basis of relocation results,the study on the stress fi eld along the fault zone was conducted,and the infl uence of seismic event position on the stress fi eld was analyzed.Results show that,fi rst,the current stress regime in the shallow crust of the Tengchong volcanic area is strike-slip faulting,the orientation of the principal compressive stress axis is NE–SW,the orientation of the principal extension stress axis is SE–NW,the principal compressive and extension stress axes are nearly horizontal,and the dip angle of intermediate principal stress axis is relatively large.This reflects that the volcanic and seismic activities in the Tengchong volcanic area are mainly controlled by the collision and squeezing eff ect of the Indian–Eurasian plate.It also refl ects that the current tensile action caused by deep magma activity has little infl uence on the shallow crustal stress field.Second,the stress field along fault zones reveals that there exist local stress fi elds,such as the thrust stress regime at the strike-slip fault terminal area,which is consistent with the compressional area at the intersection of conjugate strike-slip faults indicated by previous study.Third,the stress fi eld results are consistent,regardless of using the original location in the bulletin or the relocated location,indicating that the infl uence of the event location error can be neglected when there are suffi cient data and refl ecting the stability of the composite focal mechanism method.The findings can serve as a reference for investigating geological structure movement,seismic activities,and volcanic activities in the Tengchong volcanic area. 展开更多
关键词 Tengchong volcanic area composite focal mechanism Stress fi eld Double-diff erence location Conjugate Fault
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The Calculation of Stress-Strain State of Anisotropic Composite Finite-Element Area with Different Boundary Conditions on the Surface
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作者 Bergulyov Anton 《World Journal of Mechanics》 2014年第1期31-36,共6页
The numerical analytic research approach of stress-strain state of anisotropic composite finite element area with different boundary conditions on the surface, is represented below. The problem is solved by using a sp... The numerical analytic research approach of stress-strain state of anisotropic composite finite element area with different boundary conditions on the surface, is represented below. The problem is solved by using a spatial model of the elasticity theory. Differential equation system in partial derivatives reduces to one-dimensional problem using spline collocation method in two coordinate directions. Boundary problem for the system of ordinary higher-order differential equation is solved by using the stable numerical technique of discrete orthogonalization. 展开更多
关键词 composite FINITE-ELEMENT areas Boundary Conditions ELASTICITY Theory SPLINE Approximation COLLOCATION Methods
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Novel Nanosized Adsorbing Composite Cathode Materials for the Next Generational Lithium Battery 被引量:1
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作者 张勇 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2007年第2期234-239,共6页
A novel carbon-sulfur nano-composite material was synthesized by heating sublimed sulfur and high surface area activated carbon (HSAAC) under certain conditions. The physical and chemical per- formances of the novel... A novel carbon-sulfur nano-composite material was synthesized by heating sublimed sulfur and high surface area activated carbon (HSAAC) under certain conditions. The physical and chemical per- formances of the novel carbon-sulfur nano-composite were characterized by scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET) and X-ray diffraction (XRD). The electrochemical performances of nano-composite were characterized by charge-discharge characteristic, cyclic voltammetry and electrochemical impendence spectroscopy (EIS). The experimental results indicate that the electrochemical capability of nano- composite material was superior to that of traditional S-containing composite material. The cathode made by carbon-sulfur nano-composite material shows a good cycle ability and a high specific charge-discharge capacity. The HSAAC shows a vital role in adsorbing sublimed sulfur and the polysulfides within the cathode and is an excellent electric conductor for a sulfur cathode and prevents the shuttle behavior of the lithium-sulfur battery. 展开更多
关键词 high surface area activated carbon sublimed sulfur lithium battery composite material: adsorbing composite
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The Background of Regional Lead Isotopic Compositions and Its Application in the Lower and Middle Reaches of the Yangtze River and Neighbouring Areas 被引量:1
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作者 Ma Zhendong and Shan Guangxiang Geochemistry Institute, China University of Geosciences, Wuhan, Hubei 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 1997年第2期158-170,共13页
The paper systematically deals with the background of regional isotopic compo-sitions in the lower and middle reaches of the Yangtze River and neighbouring areas. It isshown that the lead isotopic compositions of diff... The paper systematically deals with the background of regional isotopic compo-sitions in the lower and middle reaches of the Yangtze River and neighbouring areas. It isshown that the lead isotopic compositions of different geological formations and units are con-trolled by the primary mantle heterogeneity, dynamic process of crust-mantle interchange,abundances of uraninm, thorium and lead of various layers of the earth and timing. Studies onthe background of regional isotopic compositions may offer significant information forgeochemical regionalization, tracing of sources of ore-forming materials, and regionalprognosis of ore deposits. 展开更多
关键词 background of regional lead isotopic compositions tracing action lower and middle reaches of the Yangtze River and neighbouring areas
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Zircon U-Pb Chronology and Whole-rock Sr-Nd Isotope Compositions of Granite Porphyry in the Kaladaban Area of the Northern Altyn
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作者 JIA Wenbin LI Yongsheng +1 位作者 MI Kuifeng YU Xiaofei 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2020年第1期200-201,共2页
Objective The Altyn Tagh marks the northern margin of the Qinghai-Tibet Plateau and lies between the Tarim block to the north and the Qaidam block,Qilian Orogen,and Kunlun orogenic belt to the south.The Altyn Tagh reg... Objective The Altyn Tagh marks the northern margin of the Qinghai-Tibet Plateau and lies between the Tarim block to the north and the Qaidam block,Qilian Orogen,and Kunlun orogenic belt to the south.The Altyn Tagh region contains ophiolite,high-to ultrahigh-pressure metamorphic rocks,and igneous rocks.Previous research has virified the occurrence of continental rifting,subduction,slab roll-back,and collision between the Tarim block and Proto-Tethys oceanic plate.Moreover,Kaladaban volcanic rocks are mainly distributed in the north Altyn region.Studies of the magmatic evolution of this region have proposed that Altyn oceanic plate was subducted during the Ordovician(Han et al.,2012;Wang et al.,2017).However,the specific timing and other aspects of the subduction are debated,and an investigation of granite porphyry in the Kaladaban area would improve our understanding of this subduction event.In this study,we present new U-Pb zircon dating result and Sr-Nd isotope composition data for granite porphyry from the North Altyn region.The objective is to constrain the timing of subduction of the North Altyn oceanic plate and establish the petrogenesis and magma source of the granite porphyry. 展开更多
关键词 ZIRCON U-PB CHRONOLOGY and Whole-rock SR-ND Isotope compositions of Granite PORPHYRY in the Kaladaban area of the NORTHERN Altyn NORTHERN
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Chemical Composition of Sphyraena barracuda with Different Area, Size and Season, in Sudanese Red Sea Coast
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作者 Hala Gindeel A. Ahmadoon Abdall N. Elawad +1 位作者 Alamin M. Alamin Adam A. Babiker 《Food and Nutrition Sciences》 CAS 2023年第5期415-420,共6页
This study aims to determine the effect of area, size and season on chemical composition of Sphyraena barracuda from Sudanese Red Sea Coast. A total of 180 fish samples were collected from Port Sudan and Sawakin fishi... This study aims to determine the effect of area, size and season on chemical composition of Sphyraena barracuda from Sudanese Red Sea Coast. A total of 180 fish samples were collected from Port Sudan and Sawakin fishing sites during the winter and summer of 2020-2021. The fishes sample ranged between (30 - 50) cm in total length and (250 - 1000) gm in body weight of small size, and ranged between (60 - 90) cm in total length and (1250 - 250) gm in body weight for large size. Fish flesh was subject to gross chemical analysis. Moisture, protein, fat, ash, acidity and pH were determined. The results indicated a significant effect by area, season and size. The different areas had a significant effect on crude protein and ash;higher parameter value is found in Sawakin. Higher chemical parameters were showed in winter than in summer. Also, size had a significant effect in all parameters (except moisture), fat and ash were high in large size. The study has concluded that the large size fishes of S. barracuda with high nutritional value when caught in winter from the southern region of Sawakin. 展开更多
关键词 area Chemical composition Season and Size
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Effect of pyrolysis temperature on properties of ACF/CNT composites
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作者 王丽平 黄柱成 +1 位作者 张明瑜 廖兴盛 《Journal of Central South University》 SCIE EI CAS 2012年第10期2746-2750,共5页
Activated carbon fiber/carbon nanotube(ACF/CNT) composites were fabricated by chemical vapor deposition(CVD) process.The effects of pyrolysis temperature on properties of ACF/CNT composites,including BET specific surf... Activated carbon fiber/carbon nanotube(ACF/CNT) composites were fabricated by chemical vapor deposition(CVD) process.The effects of pyrolysis temperature on properties of ACF/CNT composites,including BET specific surface area,mass increment rate and adsorption efficiency for rhodamine B in solution,were investigated by scanning electron microscopy.The results show that the pyrolysis temperature is a key factor affecting the qualities of ACF/CNT composites.The mass increment rate and BET specific surface area sharply decrease with the increase of pyrolysis temperatures from 550 ℃ to 850 ℃ and the minimum diameter of CNTs appears at 750 ℃.The maximum adsorption efficiency of ACF/CNT composites for rhodamine B is obtained at 650 ℃.ACF/CNT composites are expected to be useful in adsorption field. 展开更多
关键词 ACF/CNT composites pyrolysis temperature chemical vapor deposition BET specific surface area ADSORPTION
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Application of Heterogeneous Composite Model with Consideration of Stress Sensitive in Low Permeability Gas Reservoir
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作者 Muwang Wu Hao Liang 《International Journal of Geosciences》 2020年第11期756-767,共12页
Stress sensitivity is a key factor affecting the productivity of single wells in low permeability gas reservoirs. A well test model for heterogeneous composite gas reservoirs under the influence of stress-sensitive ef... Stress sensitivity is a key factor affecting the productivity of single wells in low permeability gas reservoirs. A well test model for heterogeneous composite gas reservoirs under the influence of stress-sensitive effects was established. Based on the theoretical model, the well test was designed by gradually increasing the pressure difference. The relationship between abnormal high pressure and reservoir stress sensitivity was analyzed. Theoretical research shows that stress sensitivity will cause permeability damage during the production process, and the pressure drop test curve shows that the physical properties of the reservoir have gradually deteriorated. The pressure recovery test curve shows that the physical properties of the reservoir are getting better. Field practice shows that stress sensitivity is related to the formation of abnormally high pressure in the formation without considering the micro-cracks in the formation. Stress-sensitive reservoirs are generally unbalanced and compacted due to overpressure, for fluid expansion/conduction overpressure in Ledong Area. For these reservoirs, there is almost no stress sensitivity. The research results have significance for guiding the design and data interpretation of stress-sensitive reservoir. 展开更多
关键词 Ledong area Stress Sensitivity composite Gas Reservoir Well Test Model UNDERCOMPACTION Fluid Expansion/Conduction
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Composite Stable to Corrosive Media in SiC-AL<sub>2</sub>O<sub>3</sub>-Si<sub>2O</sub>N<sub>2</sub>System
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作者 Z. D. Kovziridze N. S. Nizharadze +3 位作者 G. Tabatadze M. Mshvildadze E. Nikoleishvili Z. Mestvirishvili 《Journal of Electronics Cooling and Thermal Control》 2013年第2期74-84,共11页
The object of the research was to study the composite received in impure nitrogen medium from silicon carbide, silicon and refractory clay mixture. With X-ray diffraction, petrographic and electron microscope methods ... The object of the research was to study the composite received in impure nitrogen medium from silicon carbide, silicon and refractory clay mixture. With X-ray diffraction, petrographic and electron microscope methods the chemical processes happening at burning of the mentioned mixture in technical nitrogen medium and the kind of received binder, phase composition and basic properties are studied. It is stated that silicon carbide composite with complex binder is received, the main phases being: Si2ON2, 3Al2O3· 2SiO2 and SiO2. SiC-Al2O3 composite is also received and studied. Water and acid resistance of composites (H2SO4, r—1.84 g/sm3) and resistance to nonferrous metals and slag are studied. The received composites can be used for production of protective envelope of thermocouple for measuring of temperature of ferrous and nonferrous metals at high temperatures. 展开更多
关键词 composite SILICON Carbide Nitrogen area SILICON OXYNITRIDE Resistance
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Change in the Pore Structure of Carbon-Carbon Composites during Successive Stages of High-Pressure Impregnation and Heat Treatment
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作者 Ekaterina V. Koganl Yury M. Volfkovich +3 位作者 Artem P. Malakho Valery V. Kulakov Anatoly M. Kenigfest Valentin E. Sosenkin 《Journal of Chemistry and Chemical Engineering》 2012年第12期1056-1060,共5页
Pore structure of C/C (Carbon-Carbon) composite after several stages of pitch impregnation under the high pressure and heat treatment was investigated by means of low temperature nitrogen adsorption and the standard... Pore structure of C/C (Carbon-Carbon) composite after several stages of pitch impregnation under the high pressure and heat treatment was investigated by means of low temperature nitrogen adsorption and the standard contact porosimetry. Total pore volume, pore size distribution and specific surface area were calculated for samples of composite after several successive stages of treatment. The radius of pores presented in the material changes from 1 nm to 90 tam. Total pore volume and specific surface area both decrease after successive stages of pitch impregnation under the pressure, whereas heat treatment up to 1,750 ℃ and 2,000 ℃ leads to creation of some porous space and pore volume expansion. The bulk porosity of C/C composite comes down from 33.7% to 13.7% after the serial stages of treatment and the specific surface area is reduced by half compared to the initial material. 展开更多
关键词 Carbon-carbon composite pore structure total pore volume specific surface area high-pressure impregnation heattreatment.
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Oxidation and Electrical Properties of Cu-Mn_(3)O_(4)Composite Coating Obtained by Electrodeposition on SOFC Interconnects
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作者 吕烨 LUO Shengyun 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS CSCD 2023年第1期72-78,共7页
Cu-Mn_(3)O_(4)composite coating was prepared on the SUS 430 ferritic stainless steel by electrodeposition and then exposed in air at 800℃corresponding to the cathode atmosphere of solid oxide fuel cell(SOFC).A dual-l... Cu-Mn_(3)O_(4)composite coating was prepared on the SUS 430 ferritic stainless steel by electrodeposition and then exposed in air at 800℃corresponding to the cathode atmosphere of solid oxide fuel cell(SOFC).A dual-layer oxide structure mainly comprising an external layer of CuO followed by(Cu,Mn,Fe)_(3)O_(4)spinel and an internal layer of Cr-rich oxide was thermally developed on the coated steel.The scale area-specific resistances(ASRs)of the coated steels were lower than the scale ASR of the uncoated steel after identical thermal exposure.The external layer of CuO/(Cu,Mn,Fe)_(3)O_(4)spinel not only served as a barrier to reduce the growth rate of Cr-rich oxide internal layer and to suppress the outward diffusion of Cr,but also lowered the surface scale ASRs considerably. 展开更多
关键词 solid oxide fuel cell steel interconnect Cu-Mn_(3)O_(4)composite coating area specific resistance
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复合材料易碎盖承压和顶破性能研究
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作者 王宇奇 徐志明 +5 位作者 徐澧明 苑晓旭 姜悦 李爽 蔡登安 周光明 《复合材料科学与工程》 北大核心 2025年第1期109-116,共8页
本文设计了一种通道尺寸为650 mm×650 mm的复合材料薄型易碎式发射箱盖,能够承载极大内压且顶破载荷较小,内压转换为集中力的大小是顶破载荷的7倍,并提出了薄弱区以及加强布的结构设计方案。制作了易碎盖并对其进行承压与顶破试验... 本文设计了一种通道尺寸为650 mm×650 mm的复合材料薄型易碎式发射箱盖,能够承载极大内压且顶破载荷较小,内压转换为集中力的大小是顶破载荷的7倍,并提出了薄弱区以及加强布的结构设计方案。制作了易碎盖并对其进行承压与顶破试验,试验结果表明,易碎盖的设计结构合理,能够承受0.055 MPa的内压,易碎盖中心点的最大变形为19.83 mm,而顶破易碎盖仅需要3.03 kN的载荷。本文分别建立了易碎盖承压试验和顶破试验的有限元模型,分析结果与试验结果的误差分别为12.7%和8.0%,可以较为准确地预测易碎盖的变形和强度。基于有限元模型,分析了不同位置的加强布层数变化和不同易碎盖厚度对易碎盖变形的影响,Ⅱ,Ⅲ区加强布层数和易碎盖厚度的增加会导致易碎盖变形减少。本文的研究内容可以为薄型易碎式发射箱盖的工程制作提供参考。 展开更多
关键词 复合材料 大尺寸易碎盖 薄弱区结构 有限元分析
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宁东煤炭基地矸石山生态修复技术模式评价
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作者 武春丽 侯晓磊 +7 位作者 杨建英 赵廷宁 邓雅元 麻文章 巩子涵 曾文杰 芦治源 吴国伟 《生态学报》 北大核心 2025年第1期461-474,共14页
针对西北干旱煤炭矿区生态环境问题识别不清,生态修复技术模式针对性不强,措施单一等问题,以宁东煤炭基地6座煤矸石山及周边自然地为研究对象,运用主成分分析法进行立地类型划分,运用复合模糊物元熵权法从土壤改良效果、植被恢复效果和... 针对西北干旱煤炭矿区生态环境问题识别不清,生态修复技术模式针对性不强,措施单一等问题,以宁东煤炭基地6座煤矸石山及周边自然地为研究对象,运用主成分分析法进行立地类型划分,运用复合模糊物元熵权法从土壤改良效果、植被恢复效果和技术措施状况(技术措施完整性和经济性)3个方面共19项指标构建评价体系,确定各指标权重及进行综合评价,筛选不同立地类型对位生态修复技术模式,旨在为西北干旱区生态修复提供技术支撑。结果表明:(1)坡向、坡度和土层厚度为立地类型划分主导因子,据此将矸石山分厚层急阴坡、中层斜阴坡、厚层斜阴坡、薄层急阳坡、中层斜阳坡、厚层斜阳坡、中层斜半阴半阳坡、厚层斜半阴半阳坡、薄层急半阴半阳坡及厚层平台9种立地类型;(2)中层斜半阴半阳坡立地类型,推荐“砾石沙障”模式或“活体沙障”模式;厚层急阴坡、薄层急阳坡立地类型,推荐“撒播草籽+挡矸墙+环保树脂网工程护坡+排水沟+微喷”模式;中层斜阴坡、中层斜阳坡立地类型,推荐“撒播草籽+挡矸墙+排水沟+草方格”模式;厚层平台立地类型,推荐“植苗造林+草方格+截水沟”模式。 展开更多
关键词 煤炭矿区 煤矸石山 立地类型 技术模式 复合模糊物元熵权法
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许昌烟区上六片烟叶原料质量的稳定性评价
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作者 范宇鑫 何冰 +8 位作者 白峰 葛梦龙 王红霞 和梦颖 李建华 申洪涛 王艳芳 刘领 邱建华 《江西农业学报》 2025年第1期51-59,共9页
对2020-2022年许昌烟区16个收购站点上六片烟叶原料的化学成分指标和感官评吸质量进行了取样分析,评价统计了各收购站点及年际间上六片烟叶质量的稳定性,以及上六片烟叶感官评吸质量与常规化学成分的相关性。结果表明:(1)许昌烟区上六... 对2020-2022年许昌烟区16个收购站点上六片烟叶原料的化学成分指标和感官评吸质量进行了取样分析,评价统计了各收购站点及年际间上六片烟叶质量的稳定性,以及上六片烟叶感官评吸质量与常规化学成分的相关性。结果表明:(1)许昌烟区上六片烟叶内在化学成分存在较高的空间异质性,总植物碱和总氮含量较高的站点主要分布在禹州南部和襄县南部,还原糖和总糖含量较高的站点分布在襄县东部,钾含量和氯含量较高的站点分布在襄县西部和中部。(2)化学成分指标在年际间变异均较大的站点为库庄、张庄、范坡;化学成分指标的总变异系数表现为钾氯比>氯>糖碱比>钾>还原糖>总糖>总植物碱>氮碱比>总氮。(3)上六片烟叶感官评吸总分表现较好的站点主要为汾陈、姜庄、张庄、王洛,且襄县收购站点的烟叶感官评吸质量总体优于禹州;感官质量总分与还原糖、钾氯比呈显著正相关,与钾含量呈极显著正相关,与氯含量呈显著负相关;烤后烟叶的还原糖含量、钾含量、钾氯比和氯含量是影响上六片烟叶感官评吸质量的主要因子。 展开更多
关键词 许昌烟区 上六片烟叶 化学成分 变异系数 感官评吸质量 稳定性
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湿陷性黄土地区复合土工膜人工湖防渗施工
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作者 王俊英 《科学技术创新》 2025年第3期173-176,共4页
复合土工膜具有强度高、延伸性能好、耐酸碱、耐老化、防渗性能好等特点,且有良好的耐热性和耐寒性,不受工程环境限制。通过对湿陷性黄土地区复合土工膜人工湖防渗施工的研究及实施,能够确保湖体无渗漏、无下沉,节约成本,提前工期。基于... 复合土工膜具有强度高、延伸性能好、耐酸碱、耐老化、防渗性能好等特点,且有良好的耐热性和耐寒性,不受工程环境限制。通过对湿陷性黄土地区复合土工膜人工湖防渗施工的研究及实施,能够确保湖体无渗漏、无下沉,节约成本,提前工期。基于此,本文以实际工程为例,对湿陷性黄土地区复合土工膜人工湖防渗施工的施工工艺流程及操作要点进行分析,并提出相应的质量控制措施,希望能为相关人员提供参考。 展开更多
关键词 湿陷性黄土地区 复合土工膜 人工湖 防渗施工
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一种改性三元光催化复合材料制备及制氢性能试验
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作者 黄六升 《粘接》 2025年第1期90-93,共4页
为提高光催化制氢效率,降低成本,以石墨相氮化碳为主要材料,负载硫化镍和硫化钴,制备了一种三元光催化复合材料,并对其性能进行研究。试验结果表明,由X射线衍射分析(XRD)和比表面积与孔隙分析(BET)可知,试验成功制备了三元光催化复合材... 为提高光催化制氢效率,降低成本,以石墨相氮化碳为主要材料,负载硫化镍和硫化钴,制备了一种三元光催化复合材料,并对其性能进行研究。试验结果表明,由X射线衍射分析(XRD)和比表面积与孔隙分析(BET)可知,试验成功制备了三元光催化复合材料,且该材料具备较大的比表面积和较小的孔径,分别是103.5 m^(2)/g、3.68 nm。电化学测试和光催化制氢试验表明,三元光催化复合材料的光催化性能较佳,在光辐照5 h时的氢气生成量达到11.37 mmol/g,氢气生成速率为2.274 mmol/(g×h)。综上,实验所制备的硫化镍/硫化钴/石墨相氮化碳三元光催化复合材料具备较好的光催化制氢性能。 展开更多
关键词 光催化制氢 石墨相氮化碳 硫化钴 复合材料 比表面积
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Diversity and structural composition of species in dipterocarp forests:a study from Fasiakhali Wildlife Sanctuary, Bangladesh 被引量:4
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作者 S.C.Das M.S.Alam M.A.Hossain 《Journal of Forestry Research》 SCIE CAS CSCD 2018年第5期1241-1249,共9页
Fasiakhali Wildlife Sanctuary is a protected area composed of tropical remnant rainforest that harbor substantial number of large,old Garjan(Dipterocarpus spp.)trees.The present study assessed composition,structure ... Fasiakhali Wildlife Sanctuary is a protected area composed of tropical remnant rainforest that harbor substantial number of large,old Garjan(Dipterocarpus spp.)trees.The present study assessed composition,structure and diversity of the species in this protected area.A total of 32 trees species were recorded with DBH ≥ 11 cm belonging to 24 genera and 19 families.The forest is low in plant diversity as represented by Shannon–Wiener diversity and Simpson Dominance indices.Dipterocarpus turbinatus was the most dominant species with maximum relative density,frequency,dominance,and importance value index.Syzygium firmum and Tectona grandis followed in terms of dominance.The structural composition indicated higher number of individuals in the medium growth classes(41 to 〈 511 cm DBH and 16–20 m height ranges),whereas D.turbinatus was the only species that dominated most of the growth classes.Poor stem density in lower growth classes indicated meager recruitment of regeneration which may be due to lower annual precipitation,increased grazing and encroachments.This study will help to understand the patterns of tree species composition and diversity in the remnant dipterocarp forests of Bangladesh.It will also contribute to identifying threatened plants to undertake D.turbinatus based conservation and sustainable management of the Fasiakhali Wildlife Sanctuary. 展开更多
关键词 Species diversity Structural composition Protected area Importance value index Cluster analysis
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Effects of vegetation strata and human disturbance on bird diversity in green areas in a city in southern Chile 被引量:2
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作者 Andrés Munoz-Pedreros Marilyn González-Urrutia +1 位作者 Francisco Encina-Montoya Heraldo V.Norambuena 《Avian Research》 CSCD 2018年第4期329-343,共15页
Background: Urbanisation is a dominant geographical trend and an important component of global change, with unprecedented implications for socio?economic, cultural and environmental characteristics. However, green are... Background: Urbanisation is a dominant geographical trend and an important component of global change, with unprecedented implications for socio?economic, cultural and environmental characteristics. However, green areas, including original fragments, can help to conserve native diversity, improving the functioning of these artificial systems in the long term. Urban areas can still provide habitats usable by wild birds, however the structural charac?teristics of the habitat formed by different types of green area differ, and therefore dissimilar bird diversities are to be expected. The object of this study was to characterise the α and β diversities of birds in different green areas and to analyse how diversity relates to ten variables that characterise the habitat.Methods: We studied the green areas in the city of Temuco, southern Chile(Park, Square and Median strips of main streets), evaluating the variables:(a) surface area,(b) vegetation,(c) estimated human impact as the proportions of vegetation and bare soil by area, and the vehicle traffic. The bird assemblage structures were characterised by α(intra?environment) diversity and β diversity(between environments) and the statistical analysis identified the environmen?tal variables related with the presence and abundance of birds. A statistical model was constructed to describe the contribution of the variables to bird diversity.Results: We found significant differences between the diversity of bird species in the three types of green area. The β showed medium to high similarity between the different study units. There was a negative correlation with bare soil areas; the correlations with vehicle flow, plant structure and tree and shrub cover were not significant, meaning that these variables did not explain the variation in the richness of bird species between the green areas. However the surface area did explain this variation presenting a positive potential relation. There was also a high correlation with the origin(native) of shrub species.Conclusions: The bird diversity varied significantly according to the type of urban green area. The environmental variables presenting significant correlations with bird diversity were: surface area, native species of shrub stratum, shrub cover, and bare soil area. The best multiple regression model showed that the three most important variables for bird diversity are the surface area of the green area, the cover of the shrub stratum and the presence of native shrub species. 展开更多
关键词 URBAN BIRDS URBAN green area VEGETATION structure BIRD compositION Chile
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