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Monotonic triaxial testing and hypoplastic modelling of calcareous sand:A focus on particle breakage and initial relative density 认领 引用
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作者 Jiarui Chen Yaolan Tang +4 位作者 Shun Wang Chunshun Zhang Wei Wei Jie Dong Congying Li 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2026年第2期1504-1525,共22页
The stress-strain behavior of calcareous sand is significantly influencedby particle breakage(B)and initial relative density(Dri),but few constitutive models consider their combined effects.To bridge this gap,we condu... The stress-strain behavior of calcareous sand is significantly influencedby particle breakage(B)and initial relative density(Dri),but few constitutive models consider their combined effects.To bridge this gap,we conducted a series of triaxial tests on calcareous sand with varying Dri and stress paths,examining particle breakage and critical state behavior.Key findingsinclude:(1)At a constant stress ratio(η),B follows a hyperbolic relationship with mean effective stress(p'),and for a given p',B increases proportionally withη;(2)The critical state line(CSL)moves downward with increasing Dri,whereas the critical state friction angle(φcs)decreases with increasing B.Based on these findings,we propose a unifiedbreakage evolution model to quantify particle breakage in calcareous sand under various loading conditions.Integrating this model with the Normal Consolidation Line(NCL)and CSL equations,we successfully simulate the steepening of NCL and CSL slopes as B increases with the onset of particle breakage.Furthermore,we quantitatively evaluate the effect of B onφcs.Finally,within the framework of Critical State Soil Mechanics and Hypoplasticity theory,we develop a hypoplastic model incorporating B and Dri.The model is validated through strong agreement with experimental results across various initial relative densities,stress paths and drainage conditions. 展开更多
关键词 Calcareous sand Constitutive model Hypoplasticity Particle breakage Initial relative density Triaxial test
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Change in relative density of WC-Co cemented carbides in spark plasma sintering process 认领 引用 被引量：4
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作者 SUN Lan LIN Chenguang +2 位作者 JIA Chengchang JIA Xian XIAN Mina 《Rare Metals》 SCIE EI CAS 2008年第1期74-77,共4页
The relative density of WC-Co cemented carbides during spark plasma sintering（SPS） was analyzed.Based on the change in displacement of the ram in the SPS system,the relative densities in the sintering process can be... The relative density of WC-Co cemented carbides during spark plasma sintering（SPS） was analyzed.Based on the change in displacement of the ram in the SPS system,the relative densities in the sintering process can be achieved at different temperatures.The results indicated that densification of the samples started at near 900°C,the density rapidly reached its maximum at the increasing temperature stage,in which the temperature was lower than the sintering temperature of 1200°C,and most of the densification took place in the stage.Besides,the theoretical values were consistent with the experimental results. 展开更多
关键词 spark plasma sintering relative density WC-Co cemented carbides
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Role of processing parameters on relative density,microstructure and mechanical properties of selective laser melted titanium alloy 认领 引用 被引量：3
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作者 Tian-yu Liu Bo-liang Liu +4 位作者 Jiao-jiao Cheng Shi-bing Liu Kun Shi Hong-yu Liu Jun Zhao 《China Foundry》 SCIE EI CAS CSCD 2024年第6期676-684,共9页
The relationships between the selective laser melting(SLM)processing parameters including laser power,scanning speed and hatch space,the relative density,the microstructure,and resulting mechanical properties of Ti-6A... The relationships between the selective laser melting(SLM)processing parameters including laser power,scanning speed and hatch space,the relative density,the microstructure,and resulting mechanical properties of Ti-6Al-2Zr-1Mo-1V alloy were investigated in this work.The result shows that laser power acts a dominant role in determining the relative density in comparison with scanning speed and hatch space.The optimal SLM process window for fabricating relative density>99%samples is located in the energy density range of 34.72 J·mm-3to 52.08 J·mm-3,where the laser power range is between 125 W and 175 W.An upward trend is found in the micro-hardness as the energy density is increased.The optimum SLM processing parameters of Ti-6Al-2Zr-1Mo-1V alloy are:laser power of 150 W,scanning speed of 1,600 mm·s-1,hatch space of 0.08 mm,and layer thickness of 0.03 mm.The highest ultimate tensile strength,yield strength,and ductility under the optimum processing parameter are achieved,which are 1,205 MPa,1,099 MPa,and 8%,respectively.The results of this study can be used to guide SLM production Ti-6Al-2Zr-1Mo-1V alloy parts. 展开更多
关键词 selective laser melting processing parameter Ti-6Al-2Zr-1Mo-1V titanium alloy relative density microstructure mechanical properties
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Effect of sintering on the relative density of Cr-coated diamond/Cu composites prepared by spark plasma sintering 认领 引用 被引量：11
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作者 Wei Cui Hui Xu +3 位作者 Jian-hao Chen Shu-bin Ren Xin-bo He Xuan-hui Qu 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2016年第6期716-722,共7页
Cr-coated diamond/Cu composites were prepared by spark plasma sintering. The effects of sintering pressure, sintering temperature, sintering duration, and Cu powder particle size on the relative density and thermal co... Cr-coated diamond/Cu composites were prepared by spark plasma sintering. The effects of sintering pressure, sintering temperature, sintering duration, and Cu powder particle size on the relative density and thermal conductivity of the composites were investigated in this paper. The influence of these parameters on the properties and microstructures of the composites was also discussed. The results show that the relative density of Cr-coated diamond/Cu reaches ~100% when the composite is gradually compressed to 30 MPa during the heating process. The densification temperature increases from 880 to 915℃ when the diamond content is increased from 45vol% to 60vol%. The densification temperature does not increase further when the content reaches 65vol%. Cu powder particles in larger size are beneficial for increasing the relative density of the composite. 展开更多
关键词 metal matrix composites copper diamond relative density spark plasma sintering
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Design of Lattice Structures Using Local Relative Density Mapping Method 认领 引用 被引量：1
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作者 Guo-Hua Song Shi-Kai Jing +3 位作者 Fang-Lei Zhao Ye-Dong Wang Hao Xing Long-Fei Qie 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2018年第5期110-118,共9页
In order to solve the problem of substantial computational resources of lattice structure during optimization, a local relative density mapping(LRDM) method is proposed. The proposed method uses solid isotropic micros... In order to solve the problem of substantial computational resources of lattice structure during optimization, a local relative density mapping(LRDM) method is proposed. The proposed method uses solid isotropic microstructures with penalization to optimize a model at the macroscopic scale. The local relative density information is obtained from the topology optimization result. The contour lines of an optimized model are extracted using a density contour approach, and the triangular mesh is generated using a mesh generator. A local mapping relationship between the elements’ relative density and the struts’ relative cross?sectional area is established to automatically determine the diameter of each individual strut in the lattice structures. The proposed LRDM method can be applied to local finite element meshes and local density elements, but it is also suitable for global ones. In addition, some cases are con?sidered in order to test the e ectiveness of the LRDM method. The results show that the solution time of the LRDM is lower than the RDM method by approximately 50%. The proposed method provides instructions for the design of more complex lattice structures. 展开更多
关键词 Lattice structures Local relative density mapping Topology optimization Additive manufacturing
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Effect of relative density on cyclic oxidation resistance properties of MoSi_2 认领 引用
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作者 颜建辉 李益民 张厚安 《Journal of Central South University of Technology》 2008年第3期301-304,共4页
MoSi2 powders were fabricated respectively by mechanical alloying technique and sintering at different temperatures to prepare materials with different relative densities. The relative oxidation behavior of all MoSi2 ... MoSi2 powders were fabricated respectively by mechanical alloying technique and sintering at different temperatures to prepare materials with different relative densities. The relative oxidation behavior of all MoSi2 materials at 1 473 K was investigated by TGA,SEM and XRD. The results show that the "pesting" is not found in all materials after being oxidized for 480 h. The density has no essential relation to the "pesting". The oxidation curve of specimens with lower density shows two-step oxidation kinetics. Both the first stage (0-1 h) and the second stage (1-480 h) nearly obey linear kinetics,but the oxidation rates are obviously different. The oxidation kinetics of MoSi2 with higher relative density nearly follows parabolic law. The mass gains of MoSi2 with the lowest relative density (78.6%) and the highest relative density (94.8%) are increased by 10.390 and 0.135 mg/cm2,respectively. The oxide scale of materials with lower densities is non-protective and makes the oxygen diffusion easy. A dense scale in the material with higher density is formed,which acts as a diffusion barrier to the oxygen atoms to penetrate into the matrix,showing much better high temperature oxidation resistance. The phases distribution of oxidation scale from the outside to the inside is SiO2→Mo5Si3→MoSi2. 展开更多
关键词 MoSi2 relative density diffusion oxidation resistance
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Cyclic Oxidation Behaviors of MoSi_2 with Different Relative Density 认领 引用 被引量：2
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作者 YAN Jianhui ZHANG Houan +1 位作者 TANG Siwen XU Jianguang 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2008年第5期699-703,共5页
The influence of different relative density on the cyclic oxidation behaviors of MoSi2 at 1273 K were studied."Pesting"was not found in all MoSi2 materials after being oxidized for 480 h.All samples exhibite... The influence of different relative density on the cyclic oxidation behaviors of MoSi2 at 1273 K were studied."Pesting"was not found in all MoSi2 materials after being oxidized for 480 h.All samples exhibited continuous mass gain during the oxidation process.The mass gains of MoSi2 with the lowest relative density(78.6%)and the highest relative density(94.8%)are increased by 8.15 mg·cm^-2 and 3.48 mg·cm^-2,respectively.The surface of the material with lower relative density formed a loose,porous and discontinuous oxidation scale,which accelerated oxygen diffusion and aggravated the oxidation process.However,a dense scale in the material with higher relative density is formed,which acts a diffusion barrier to the oxygen atoms penetrating into the matrix.The high temperature oxidation resistance of MoSi2 can be improved by increasing its relative density. 展开更多
关键词 molybdenum disilicide relative density cyclic oxidation
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Unified Approach to Assess Engineering Performance of Fill Improved by Shallow to Deep Compaction Based Techniques Using Relative Density 认领 引用
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作者 Ahmed Alaaeldin Emmanouil Spyropoulos Anas Orabi 《Open Journal of Civil Engineering》 2020年第3期239-249,共11页
The setting of pre assessment criteria for soil compaction is hardly determined, especially, in case of undecided structure locations. Different design guidelines recommend achieving a specific value of relative densi... The setting of pre assessment criteria for soil compaction is hardly determined, especially, in case of undecided structure locations. Different design guidelines recommend achieving a specific value of relative density for the compaction of fill placement works. Alternatives were discussed through the literature to predict the value of relative density based on soil field tests (e.g. cone and standard penetration tests). This paper presents the weakness of using the Over Consolidation Ratio (OCR) as guidance to assess the value of cone tip resistance using the soil relative density. The variation of OCR (from 1 to 10) has a significant effect on the qc value up to 110% when compared to the normally consolidated state. Then normally consolidated state can logically cover the compaction process with variation of 20%, 33%, and 4% for relative density values 85%, 70%, and 60%, respectively. A unified approach is recommended to predict the compaction qc-performance line using normally consolidated condition and sand relative density. 展开更多
关键词 Compaction Relative Density Performance Specifications
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Influence Mechanism of Process Parameters on Relative Density, Influence Mechanism of Process Parameters on Relative Density, Microstructure, and Mechanical Properties of Low Sc-Content Al-Mg-Sc-Zr Alloy Fabricated by Selective Laser Melting 认领 引用 被引量：5
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作者 Di Wang Yongwei Feng +6 位作者 Linqing Liu Xiongmian Wei Yongqiang Yang Pan Yuan Yang Liu Changjun Han Yuchao Bai 《Chinese Journal of Mechanical Engineering(Additive Manufacturing Frontiers)》 2022年第4期3-15,共13页
Additive manufacturing of Al-Mg-Sc-Zr alloys is a promising technique for the fabrication of lightweight components with complex shapes.In this study,the effect of the process parameters of selective laser melting(SLM... Additive manufacturing of Al-Mg-Sc-Zr alloys is a promising technique for the fabrication of lightweight components with complex shapes.In this study,the effect of the process parameters of selective laser melting(SLM)on the surface morphology,relative density,microstructure,and mechanical properties of Al-Mg-Sc-Zr high-strength aluminum alloys with low Sc content was systematically investigated.The results show that the energy density has an important effect on the surface quality and densification behavior of the Al-Mg-Sc-Zr alloy during the SLM process.As the energy density increased,the surface quality and the number of internal pores increased.However,the area of the fine-grained region at the boundary of the molten pool gradually decreased.When the laser energy density was set to 151.52 J/mm3,a low-defect sample with a relative density of 99.2%was obtained.After heat treatment,the area of the fine grains at the boundary increased significantly,thereby contributing to the excellent mechanical properties.The microstructure was characterized by a unique“fan-shaped”heterogeneous structure.As the energy density increased,the microhardness first increased and then decreased,reaching a maximum value of 122 HV0.3.With the optimized process parameters,the yield strength(YS),ultimate tensile strength(UTS),and elongation of the as-built Al-Mg-Sc-Zr alloys were 346.8±3.0 MPa,451.1±5.2 MPa,14.6%±0.8%,respectively.After heat treatment at 325°C for 8 h,the hardness increased by 38.5%to 169 HV0.3,and the YS and UTS increased by 41.3%and 18.1%,respectively,to 490.0±9.0 MPa and 532.7±7.8 MPa,respectively,while the elongation slightly decreased to 13.1%±0.7%. 展开更多
关键词 Selective laser melting Al-Mg-Sc-Zr alloy Process parameter Relative density Microstructure Mechanical property Surface morphology
Preparation of indium tin oxide targets with a high density and single phase structure by normal pressure sintering process 认领 引用 被引量：11
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作者 LIU Chen LIU Jiaxiang WANG Yue 《Rare Metals》 SCIE EI CAS CSCD 2011年第2期126-130,共5页
The present work mainly describes the technology for preparing indium-tin oxide(ITO)targets by cold isostatic pressing(CIP)and normal pressure sintering process.ITO powders were produced by chemical co-precipitation a... The present work mainly describes the technology for preparing indium-tin oxide(ITO)targets by cold isostatic pressing(CIP)and normal pressure sintering process.ITO powders were produced by chemical co-precipitation and shaped into an ITO green compact with a relative density of 60%by CIP under 300 MPa.Then,an ITO target with a relative density larger than 99.6%was obtained by sintering this green compact at 1550℃for 8 h.The effects of forming pressure,sintering temperature and sintering time on the density of the target were inves-tigated.Also,a discussion was made on the sintering atmosphere. 展开更多
关键词 thin films indium tin oxide(ITO) isostatic pressing sintering relative density microstructure
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Species Richness, Diversity and Density of Understory Vegetation along Disturbance Gradients in the Himalayan Conifer Forest 认领 引用 被引量：4
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作者 Kesang WANGCHUK András DARABANT +3 位作者 Prem Bahadur RAI Maria WURZINGER Werner ZOLLITSCH Georg GRATZER 《Journal of Mountain Science》 SCIE CSCD 2014年第5期1182-1191,共10页
We investigated whether species richness, diversity and density of understory herbaceous plants differed along logging(gap) and grazing(primarily by cattle) disturbance gradients, and sought to identify drivers of ric... We investigated whether species richness, diversity and density of understory herbaceous plants differed along logging(gap) and grazing(primarily by cattle) disturbance gradients, and sought to identify drivers of richness, diversity and density of understory vegetation of logged sites. A factorial experiment was conducted in the mixed conifer forest of Gidakom in Western Bhutan. Levels of the logging treatment included small(0.15 – 0.24 ha), medium(0.25 – 0.35 ha) and large(0.36 – 1.31 ha) gaps. The grazing treatment included grazed(primarily by cattle) and ungrazed(where herbivores were excluded by a fence) plots nested within each gap. Data were collected from 12 gaps(4 replicates at each level of logging) using the point intercept method. Shannon Weaver Diversity and Margalef's indices were used to estimate species diversity and describe species richness, respectively. Soil samples were analyzed for pH and nutrients. The interaction effect of logging and grazing was significant(p≤0.001) only on species diversity. Relative to ungrazed areas, species diversity was significantly higher(0.01≤p≤0.05) in medium grazed gaps. Under grazed conditions, soil P was negatively correlated with gap size and species diversity. While species diversity was positivelycorrelated(0.01≤p≤0.05) with soil N in grazed plots species richness was positively correlated(0.001≤p≤0.01) with soil N in ungrazed plots. Relative density of Yushania microphylla and Carex nubigena were higher under ungrazed conditions. Our study suggests that the combined effect of cattle grazing and logging results in higher species diversity of understory vegetation in medium and grazed gaps in mixed conifer forests of Bhutan,whereas increase or decrease in relative density of major species is determined primarily by the independent effects of grazing and logging. From management perspective, forest managers must refrain from creating large gaps to avoid loss of nutrients(mainly P and N), which may eventually affect tree regeneration. Managers intending to maintain understory vegetation diversity must consider the combined effects of grazing and logging, ensuring low to moderate grazing pressure. 展开更多
关键词 Forest gap Grazing Relative density Soil nutrients Species diversity Species richness
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ASSOCIATION BETWEEN LOW- DENSITY LIPOPROTEIN RECEPTOR- RELATED PROTEIN GENE, BUTYRYLCHOLINESTERASE GENE AND ALZHEIMER'S DISEASE IN CHINESE 认领 引用 被引量：8
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作者 毕胜 张昱 +2 位作者 吴江 王德生 赵庆杰 《Chinese Medical Sciences Journal》 CAS 2001年第2期71-75,共5页
Objective. To research the relations between low- density lipoprotein receptor- related protein gene (LRP) polymorphism, butyrylcholinesterase gene (BchE) polymorphism and Alzheimer’s disease (AD) in Chinese. Methods... Objective. To research the relations between low- density lipoprotein receptor- related protein gene (LRP) polymorphism, butyrylcholinesterase gene (BchE) polymorphism and Alzheimer’s disease (AD) in Chinese. Methods. The gene polymorphisms of LRP and BchE were genotyped in 38 AD cases and 40 controls with polymerase chain reaction- restriction fragment length polymorphism (PCR- RFLP) methods. AD groups were classified according to the LRP C/C genotype and compared with matched controls. Results. AD group had higher frequencies of C/C homozygote (81.6％ vs 60.0％ , P< 0.05) and of C allele (89.5％ vs 76.3％ , P< 0.05),with no significant difference between any of these LRP genotypes classified AD groups and their respective control groups. Conclusions. A positive correlation was found between LRP gene polymorphism and AD, but not between BchE gene polymorphism and AD in Chinese AD cases. 展开更多
关键词 Alzheimer's disease low- density lipoprotein receptor- related protein gene butyrylcholinesterase gene
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Dose Calculation Accuracy of Individualized Bulk Electron Density Assignment Approaches for Simulated MRI-only Planning of Thoracic Tumors 认领 引用
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作者 Shuxu Zhang Qingxing Zeng +7 位作者 Yuliang Liao Shengqu Lin Guoquan Zhang Huaiyu Lei Ruihao Wang Hui Yu Quanbin Zhang Ping Li 《Chinese Journal of Biomedical Engineering(English Edition)》 CAS 2020年第3期40-46,共7页
Objective This study aimed to investigate the dose calculation accuracy of individualized bulk electron density(IBED)assignment approaches for simulated magnetic resonance imaging(MRI)-only planning of thoracic tumors... Objective This study aimed to investigate the dose calculation accuracy of individualized bulk electron density(IBED)assignment approaches for simulated magnetic resonance imaging(MRI)-only planning of thoracic tumors via the use of a 3 DVH system.Methods 8 patients with thoracic cancer were included in this study.Based on standard planning CT,single-arc dynamic conformal therapy(DCT)and double-arc volumetric modulated arc therapy(VMAT)plans with a6 MV photon beam were generated as a baseline plan(Plan-CT)for each patient.The simulated MRI-only planning(Plan-IBED)was implemented by copying the Plan-CT and forcing the electron density of each region of interest to its average value and recalculating the dose distribution.A 3 DVH system was used to visualize and compare the dosimetric differences between Plan-CT and Plan-IBED,and the criteria of the 3 D-Gamma pass rate were set to 1.0%/1.0 mm.Results The maximum percentage relative deviation(MPRD)of the dosimetric parameters D2,D95,D98,and Dmean of planning tumor volumes(PTVs)between Plan-CT and Plan-IBED was less than 1.3%.The MPRD of the average dose for organs at risk(OARs)was less than 1.5%.The MPRDs of the lung V5,V20,and V30 were 1.29%,3.26%,and 2.78%,respectively.Gamma analysis revealed an averaged pass rate of>95.0%for the body,as well as between 91.9%and 98.2%for OARs.Conclusion The proposed IBED assignment in simulated MRI-only treatment planning allows for dose calculation with comparable accuracy to the baseline plan and is appropriate for thoracic tumors. 展开更多
关键词 Individualized bulk electron density(IBED) Relative electron density(RED) Thoracic cancer 3DVH software MRI-only planning
Low density lipoprotein receptor-related protein 8:a critical receptor for tick-borne encephalitis virus entry 认领 引用
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作者 Pengtao Jiao Lin Du Yan Zeng 《Signal Transduction and Targeted Therapy》 SCIE CSCD 2026年第1期16-18,共3页
Recently,two groups identified low-density lipoprotein receptorrelated protein 8(LRP8)as a functional entry receptor for tickborne encephalitis virus(TBEV)in Nature1 and PNAS2 respectively.These two studies shed cruci... Recently,two groups identified low-density lipoprotein receptorrelated protein 8(LRP8)as a functional entry receptor for tickborne encephalitis virus(TBEV)in Nature1 and PNAS2 respectively.These two studies shed crucial light on the role of LRP8 in the neuropathogenesis of TBEV and lay a solid foundation for the development of LRP8-targeted antiviral therapeutics and vaccines.Tick-borne encephalitis virus(TBEV)is a clinically significant orthoflavivirus transmitted to humans predominantly via the bite of infected ticks.It targets the central nervous system(CNS),leading to neurological complications and potentially fatal outcomes in severe cases across Europe and Asia.3 With the expansion of TBE-endemic areas,vaccines are available,but no specific antiviral drugs exist for TBEV infection,highlighting the urgent need for in-depth research into TBEV pathogenic mechanisms and the development of effective preventive and therapeutic strategies.4 TBEV entry into host cells relies on host factors,particularly cellular receptors,which have not been definitively identified before,hindering the advancement of antiviral strategies. 展开更多
关键词 orthoflavivirus central nervous system low density lipoprotein receptor related protein antiviral therapeutics vaccines neuropathogenesis host factors tickborne encephalitis virus tbev
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Understanding the extrusion microstructures in Mg alloys due to solute segregation 认领 引用 被引量：1
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作者 Dongfang Shi Ziliang Lu +3 位作者 Yunhao Fan Yinghang Liu Xiaoqin Zeng Leyun Wang 《Journal of Magnesium and Alloys》 SCIE EI CAS CSCD 2025年第6期2670-2679,共10页
Grain boundary segregation(GBS)of solutes influences the grain size,texture,and strength of Mg wrought alloys.So far,solutes'GBS in Mg has mostly been investigated by qualitative experimental observations.In this ... Grain boundary segregation(GBS)of solutes influences the grain size,texture,and strength of Mg wrought alloys.So far,solutes'GBS in Mg has mostly been investigated by qualitative experimental observations.In this work,we develop a quantitative model to compute the grain boundary segregation energy(ΔEseg)in binary Mg based alloys that takes the relative atomic density of GB into account.The model is utilized to computeΔEsegof Al,Zn,Ca,Sn,Y,Gd,and Nd solutes in Mg.The result suggests that rare earth elements and Ca are more prone to GBS than Al,Zn,and Sn.Segregation of Gd solutes can explain the smaller grain size and slower grain growth in Mg-Gd extruded alloys than Mg-Al and Mg-Zn counterparts.It also provides an explanation for the weak extrusion texture in Mg-Gd. 展开更多
关键词 Mg alloys solute segregation grain boundary segregation gbs grain boundary segregation qualitative experimental observationsin rare earth elemen relative atomic density quantitative model
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Properties and microstructure of Cu/diamond composites prepared by spark plasma sintering method 认领 引用 被引量：11
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作者 陶静梅 朱心昆 +2 位作者 田维维 杨鹏 杨浩 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2014年第10期3210-3214,共5页
Cu/diamond composites have been considered as the next generation of thermal management material for electronic packages and heat sinks applications. Cu/diamond composites with different volume fractions of diamond we... Cu/diamond composites have been considered as the next generation of thermal management material for electronic packages and heat sinks applications. Cu/diamond composites with different volume fractions of diamond were successfully prepared by spark plasma sintering（SPS） method. The sintering temperatures and volume fractions（50%, 60% and 70%） of diamond were changed to investigate their effects on the relative density, homogeneity of the microstructure and thermal conductivity of the composites. The results show that the relative density, homogeneity of the microstructure and thermal conductivity of the composites increase with decreasing the diamond volume fraction; the relative density and thermal conductivity of the composites increase with increasing the sintering temperature. The thermal conductivity of the composites is a result of the combined effect of the volume fraction of diamond, the homogeneity and relative density of the composites. 展开更多
关键词 Cu/diamond composites spark plasma sintering relative density thermal conductivity
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Compressive properties and energy absorption characteristics of open-cell nickel foams 认领 引用 被引量：7
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作者 范素峰 张涛 +6 位作者 余琨 房宏杰 熊汉青 戴翌龙 马家骥 姜大越 朱化龙 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2017年第1期117-124,共8页
Open-cell nickel foams with different relative densities and pre-stretching degrees were subjected to room temperature quasi-static compressive tests to explore their compressive properties. The compressive properties... Open-cell nickel foams with different relative densities and pre-stretching degrees were subjected to room temperature quasi-static compressive tests to explore their compressive properties. The compressive properties of the nickel foams including yield strength, elastic modulus, energy absorption density and energy absorption efficiency were calculated accurately. The results show that the compressive properties of yield strength, elastic modulus and energy absorption density increase with the increase of relative density of nickel foams. The compressive properties are sensitive to the pre-stretching degree, and the values of yield strength, elastic modulus and energy absorption density decrease with the increase of pre-stretching degree. However, the energy absorption efficiency at the densification strain state exhibits the independence of relative density and pre-stretching degree. The value of energy absorption efficiency reaches its peak when the strain is at the end of the collapse plateau region. 展开更多
关键词 nickel foam compressive property relative density pre-stretching degree
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Effects of Nd3+on the microstructure and magnetic properties of Ni-Zn ferrites 认领 引用 被引量：8
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作者 FAN Xiufeng REN Huiping +2 位作者 ZHANG Yanghuan GUO Shihai WANG Xinlin 《Rare Metals》 SCIE EI CAS 2008年第3期287-291,共5页
Ni0.4Zn0.6Fe2-xNdxO4（x = 0-0.07） ferrites doped with different amounts of Nd2O3 were prepared using standard ceramic technique. The samples were uniaxially pressed and sintered at 1250℃ for 4 h in air. The phase st... Ni0.4Zn0.6Fe2-xNdxO4（x = 0-0.07） ferrites doped with different amounts of Nd2O3 were prepared using standard ceramic technique. The samples were uniaxially pressed and sintered at 1250℃ for 4 h in air. The phase structure and microstructure of the samples were investigated using X-ray diffraction and scanning electron microscope, respectively. The complex permeability was measured using the impedance analyzer in the range of 1-100 MHz. The results indicate that with increasing Nd^3＋ content, the relative density and lattice parameter a of the sintered samples increase, whereas the real part of permeability （μ′） and the magnetic loss tangent （tan δ） decrease. The substitution of Nd^3＋ for Fe^3＋ forms a secondary phase on the grain boundary of the matrix, which strongly restrains the grain growth of the matrix. 展开更多
关键词 Ni-Zn ferrite microstructure complex permeability relative density
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Demographic changes in China’s forests from 1998 to 2018 认领 引用 被引量：4
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作者 Yanli Dong Evgenios Agathokleous +1 位作者 Shirong Liu Zhen Yu 《Forest Ecosystems》 SCIE CSCD 2023年第1期82-91,共10页
Background: Tree demography is an essential indicator of various forest ecosystem services, and understanding its changes is critical for the sustainable management of forests. During the past four decades, China impl... Background: Tree demography is an essential indicator of various forest ecosystem services, and understanding its changes is critical for the sustainable management of forests. During the past four decades, China implemented unprecedented forest restoration projects, which altered tree demography by increasing the number of trees and introducing new species. However, it remains unclear how species composition has changed in China in response to the past forest restoration and demographical processes.Methods: We applied Forest Stability Index(FSI) and the relative change of FSI(%FSI) to describe the population dynamics of tree species and structure in China since 1998, using field-survey data collected from over 200,000plot-records from the 6th to 9th National Forest Inventories(NFIs).Results: The overall populations of both natural and planted forests have grown rapidly from 1998 to 2018, while the range of changes in the relative tree density was more variable for natural forests(ranging from-8.53% to42.46%) than for planted forests(ranging from-1.01% to 13.31%). The populations declined only in some of the tree species, including Betula platyphylla, Ulmus pumila, and Robinia pseudoacacia. In contrast, the populations of trees in the largest size-class either remained stable or expanded.Conclusions: Tree density of China?s forests(both natural and planted forests) generally expanded and the overall populations increased in most size classes, with greater increases occurred in planted forests. In contrasting to the global decline trends of large diameter trees, here we found no apparent decline for trees in the largest size-class in China, highlighting China?s success in improving forest health and forest adaptations to climate change. We advocate for more studies to reveal the mechanisms of the changes in tree demography, which will help to improve forest ecosystem services such as the carbon sequestration capacity. 展开更多
关键词 Tree demography Forest stability index(FSI) Relative change of FSI(%FSI) Relative density Tree species Tree size-class
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Effect of Particle Size on Target Sintering Behavior of Cubic ITO Nanopowders 认领 引用 被引量：3
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作者 ZHAI Xiaoyu PENG Xiang +2 位作者 MA Yunqian LIU Ting LIU Jiaxiang 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2020年第6期1098-1103,共6页
The effect of particle size on the density and resistivity of ITO green bodies and targets was systematically investigated.The experimental results show that the relative density of ITO green bodies decreases with the... The effect of particle size on the density and resistivity of ITO green bodies and targets was systematically investigated.The experimental results show that the relative density of ITO green bodies decreases with the increase of ITO particle size.When the particle size is 10.7 nm,the relative density of ITO green bodies rises to the maximum value of 56.6%.The resistivity declines exponentially with the increase of particle size,which satisfies the exponential equation of R=exp(-41.823 × d).When the particle size is 41.6 nm,the resistivity reaches the minimum value of 0.8 Ω·cm.The relative density of ITO target decreases with the increase of particle size.Fine particles can increase the driving force of densification in initial stage.Electron mobility,caused by grain boundary scattering,will increase due to the increase of particle size or the decrease of grain boundary potential.When the particle size is 10.7 nm,the target with compact grain stacking and low porosity shows a maximum relative density of 99.25%,and the resistivity reaches the minimum value of 0.34×10^-3 Ω·cm. 展开更多
关键词 indium tin oxide nanoparticles particle size indium tin oxide target relative density resistivity
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