期刊文献+
共找到65篇文章
< 1 2 4 >
每页显示 20 50 100
Method to measure tree-ring width,density,elemental composition,and stable carbon and oxygen isotopes using one sample 被引量:1
1
作者 Chenxi Xu Yaru Zhao +4 位作者 Wenling An Qingyu Zhao Yucheng Liu Masaki Sano Takeshi Nakatsuka 《Journal of Forestry Research》 SCIE EI CAS CSCD 2024年第3期167-174,共8页
Tree-ring width(RW),density,elemental com-position,and stable carbon and oxygen isotope(δ^(13)C,δ^(18)O)are widely used as proxies to assess climate change,ecology,and environmental pollution;however,a specific pret... Tree-ring width(RW),density,elemental com-position,and stable carbon and oxygen isotope(δ^(13)C,δ^(18)O)are widely used as proxies to assess climate change,ecology,and environmental pollution;however,a specific pretreat-ment has been needed for each proxy.Here,we developed a method by which each proxy can be measured in the same sample.First,the sample is polished for ring width meas-urement.After obtaining the ring width data,the sample is cut to form a 1-mm-thick wood plate.The sample is then mounted in a vertical sample holder,and gradually scanned by an X-ray beam.Simultaneously,the count rates of the fluorescent photons of elements(for chemical characteriza-tion)and a radiographic grayscale image(for wood density)are obtained,i.e.the density and the element content are obtained.Then,cellulose is isolated from the 1-mm wood plate by removal of lignin,and hemicellulose.After producing this cellulose plate,cellulose subsamples are separated by knife under the microscope for inter-annual and intra-annual stable carbon and oxygen isotope(δ^(13)C,δ^(18)O)analysis.Based on this method,RW,density,elemental composition,δ^(13)C,and δ^(18)O can be measured from the same sample,which reduces sample amount and treatment time,and is helpful for multi-proxy comparison and combination research. 展开更多
关键词 Tree-ring width Tree-ring density Tree-ring elemental composition Tree-ring stable carbon and oxygenisotopes
下载PDF
Elemental Composition of the Shell of the Testate Amoeba Difflugia tuberspinifera (Sarcodina:Rhizopoda) 被引量:4
2
作者 杨军 Louis BEYENS +1 位作者 沈韫芬 冯伟松 《Zoological Research》 CAS CSCD 北大核心 2004年第5期452-455,共4页
X-ray microanalysis was used to study the elemental composition of the shell of the freshwater testate amoeba Difflugia tuberspinifera Hu et al.,1997 collected from Mulan Lake,Hubei province,China in July 2003.The res... X-ray microanalysis was used to study the elemental composition of the shell of the freshwater testate amoeba Difflugia tuberspinifera Hu et al.,1997 collected from Mulan Lake,Hubei province,China in July 2003.The results show that the shell is composed of ten elements:Si in greater quantity;then Ca and Al;and traces of K,Na,Cl,Fe,Mg,S and P.The analysis of results suggests that D.tuberspinifera in elemental composition appears to occupy a middle position between marine and soil testate amoebae. 展开更多
关键词 Testate amoebae Difflugia tuberspinifera X-ray microanalysis elemental composition
下载PDF
Comparative Studies on the Fine Structure and Elemental Composition of Envelopes of Trachelomonas and Strombomonas (Euglenophyta) 被引量:1
3
作者 王全喜 刘洪家 +3 位作者 于晶 孙世琴 张大维 包文美 《Acta Botanica Sinica》 CSCD 2003年第5期601-607,共7页
Fine structure and elemental composition of envelopes of 10 taxa of Trachelomonas and Strombomonas from natural freshwater bodies in China were studied and phylogeny of both genera were discussed. The results indicate... Fine structure and elemental composition of envelopes of 10 taxa of Trachelomonas and Strombomonas from natural freshwater bodies in China were studied and phylogeny of both genera were discussed. The results indicate that iron (Fe) and silicon (Si) are the primary mineral elements of the envelopes. Composition of mineral elements was uncorrelated with envelope color, however, it was highly correlated with the microarchitecture of the envelopes. Content of Si was higher than that of Fe in all species of Strombomonas and some species of Trachelomonas with rough surface. In most species of Trachelomonas, especially those with dense and smoothy surface, content of Fe was higher than that of Si. Based on the above results, we propose to assign those species of Strombomonas into Trachelomonas and consider them as a group of the latter. These species were the most primitive among the group with envelopes in Euglenaceae. 展开更多
关键词 Trachelomonas Strombomonas ENVELOPE elemental composition fine structure
下载PDF
Rice Grains from Slightly Saline Field Exhibited Unchanged Starch Physicochemical Properties but Enhanced Nutritional Values
4
作者 Supranee SANTANOO Wichian SANGWONGCHAI +4 位作者 Maysaya THITISAKSAKUL Suphatta PHOTHISET Paweena PONGDONTRI Noppawan NOUNJAN Piyada THEERAKULPISUT 《Rice science》 SCIE CSCD 2024年第3期343-360,I0055-I0057,共21页
This study aims to investigate grain quality and nutritional values of rice(Pokkali,a salt-tolerant cultivar;RD73,a new cultivar improved from KDML105 introgressed with Saltol QTL from Pokkali,and KDML105,a moderately... This study aims to investigate grain quality and nutritional values of rice(Pokkali,a salt-tolerant cultivar;RD73,a new cultivar improved from KDML105 introgressed with Saltol QTL from Pokkali,and KDML105,a moderately salt-susceptible cultivar)grown under non-saline(0.04–0.87 dS/m)and slightly saline(1.08–4.83 dS/m)field conditions.The results revealed that salinity caused significant reduction in grain size but significant increments in reducing sugar and total protein contents in the grains.Nevertheless,the amounts of starch in the grains of KDML105 and Pokkali rice genotypes were unaffected by the stress.The starch granule size distribution was also unaffected by salinity.Interestingly,only starch from Pokkali was significantly diminished in amylose content,from 19.18%to 16.99%.Accordingly,parameters relating to starch gelatinization,retrogradation,and pasting properties of KDML105 and RD73 were unaffected by salinity;only Pokkali showed a significant increase in percentage of retrogradation along with a significant reduction in gelatinization enthalpy.In the saline field,total phenolic content and antioxidant capacity in the grains of all rice cultivars tended to increase,particularly in Pokkali.On average,essential element contents in grains from the saline-treated plants showed a 33%,32%,32%,22%,20%,11%,and 10%increase in total P,N,K,Mg,Zn,Fe,and Ca content,respectively.Interestingly,total Fe content exhibited the greatest percentage of increments in KDML105(187%).Taken together,cultivation of rice in the slightly saline field did not alter its eating and cooking qualities,while enhanced some nutritional properties such as proteins,minerals,and secondary metabolites like phenolic compounds. 展开更多
关键词 antioxidant capacity elemental composition GELATINIZATION grain morphology RETROGRADATION rice salt stress starch granule
下载PDF
Principles of Technology for Bottling Medicinal Mineral Waters of Sairme Using the Example of Source №3a
5
作者 Irina Nikolaishvili Giorgi Kvartskava 《American Journal of Analytical Chemistry》 CAS 2024年第4期135-138,共4页
Sairme mineral water, one of the famous mineral waters in Georgia, is renowned for its exceptional healing properties. The distinctiveness and therapeutic benefits of the naturally sourced mineral water, known as “Sa... Sairme mineral water, one of the famous mineral waters in Georgia, is renowned for its exceptional healing properties. The distinctiveness and therapeutic benefits of the naturally sourced mineral water, known as “Sairme”, stem from its rich array of microelements, notably including iron and manganese. Since 1948, the bottling of Sairme mineral water has been a prominent activity. Named after the Sairme deposit, this mineral water is packaged in various formats to cater to diverse consumer preferences. The bottling process involves transporting the mineral water from wells to the bottling plant through pipelines. Prior to bottling, the mineral water undergoes meticulous processing stages in adherence to current Georgian and international regulations. This process ensures that the concentration of trace elements in the bottled water is minimized, maintaining its purity and quality. Given the importance of preserving the microelements present in bottled mineral water, our research is dedicated to optimizing the technological process. Our objective is to safeguard the valuable microelements while ensuring the highest standards of quality and safety in the final product. 展开更多
关键词 Sairme Mineral Water Deposit Oxidation-Reduction Potential Trace elements Chemical Composition SEASONALITY
下载PDF
Elemental Composition and Geochemical Characteristics of Iron-Manganese Nodules in Main Soils of China 被引量:11
6
作者 TAN Wen-Feng LIU Fan +2 位作者 LI Yong-Hua HU Hong-Qing HUANG Qiao-Yun 《Pedosphere》 SCIE CAS CSCD 2006年第1期72-81,共10页
Elemental composition and geochemical characteristics of iron-manganese nodules from nine main soils in China were studied by chemical and multivariate statistical analyses to better understand the reactions and funct... Elemental composition and geochemical characteristics of iron-manganese nodules from nine main soils in China were studied by chemical and multivariate statistical analyses to better understand the reactions and functions of iron-manganese nodules in soils and sediment. Compared to the corresponding soils, Mn, Ba, Cd, Co and Pb had strong accumulation, Ni had moderate accumulation, while Ca, Cu, Fe, Na, P, Sr and Zn accumulated to a minor degree in the iron-manganese nodules. In contrast, Si, Al, K, Mg and Ti were reduced in the iron-manganese nodules. The contents of Ba, Cd, Co, Cu, Ni, Pb and Zn were positively and significantly correlated with that of MnO2 in the iron-manganese nodules, while the contents of Cr, Cu, Ni, Pb and Zn were positively and significantly correlated with that of Fe2O3 in soils. Based on a principle component analysis, the elements of iron-manganese nodules were divided into four groups: 1) Mn, Ba, Cd, Co, Cu, Li, Ni, Pb and Zn that were associated with Mn oxides, 2) Fe, Cr and P that were associated with Fe oxides, 3) Si, K, and Mg that were included in the elemental composition of phyllosilicate, and 4) Ca, Na, Al and Ti that existed in todorokite, birnessite, lithiophorite and phyllosilicate. It was suggested that accumulation, mineralization and specific adsorption were involved in the formation processes of soil iron-manganese nodules. 展开更多
关键词 elemental composition geochemical characteristics iron-manganese nodule soil
下载PDF
Characteristics of Elemental Composition of PM_(2.5) in the Spring Period at Tongyu in the Semi-arid Region of Northeast China 被引量:7
7
作者 张仁健 符淙斌 +1 位作者 韩志伟 朱崇抒 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2008年第6期922-931,共10页
Continuous observations of mass concentration and elemental composition of aerosol particles (PM2.5) were conducted at Tongyu, a semi-arid site in Northeast China in the spring of 2006. The average mass concentratio... Continuous observations of mass concentration and elemental composition of aerosol particles (PM2.5) were conducted at Tongyu, a semi-arid site in Northeast China in the spring of 2006. The average mass concentration of PM2.5 at Tongyu station was 260.9±274.4 μg m^-3 during the observation period. Nine dust events were monitored with a mean concentration of 528.0±302.7 μgm^-3. The PM2.5 level during non- dust storm (NDS) period was 111.65±63.37 μg m^-3. High mass concentration shows that fine-size particles pollution was very serious in the semi-arid area in Northeast China. The enrichment factor values for crust elements during the dust storm (DS) period are close to those in the NDS period, while the enrichment factor values for pollution elements during the NDS period are much higher than those in the DS period, showing these elements were from anthropogenic sources. The ratios of dust elements to Fe were relative constant during the DS period. The Ca/Fe ratio in dust aerosols at Tongyu is remarkably different from that observed in other source regions and downwind regions. Meteorological analysis shows that dust events at Tongyu are usually associated with dry, low pressure and high wind speed weather conditions. Air mass back-trajectory analysis identified three kinds of general pathways were associated with the aerosol particle transport to Tongyu, and the northwest direction pathway was the main transport route. 展开更多
关键词 dust aerosol mass concentration elemental composition transport pathway
下载PDF
Elemental Composition Method in Thermodynamics of Mul- tireaction Systems (I) Molar Number, Thermodynamic Properties and Partial Properties Relations 被引量:1
8
作者 林金清 李浩然 韩世钧 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2001年第1期100-104,共5页
When species in the solution undergo multiple chemical reactions, the solution may be treated as a solution of all species actually present or as a hypothetical solution composed of elemental species. Based on the fu... When species in the solution undergo multiple chemical reactions, the solution may be treated as a solution of all species actually present or as a hypothetical solution composed of elemental species. Based on the fundamental thermodynamic principle, the relationships of mole numbers, molar fractions, thermodynamic properties, partial molar properties, potential and fugacity between the hypothetical solution of elemental species and the equilibrated solution of actual species were derived. The hypothetical elemental solution provides a way of reducing the dimensionality of problem, simplifying the analysis and visualizing the phase behavior. 展开更多
关键词 elemental composition dimension reduction multireaction phase equilibrium THERMODYNAMICS
下载PDF
Siderophile Element Compositions of Pyroxenes in HED Meteorites: Implications for the Differentiation of Magma Ocean on Vesta 被引量:2
9
作者 CHEN Hongyi MIAO Bingkui +1 位作者 XIE Lanfang SHAO Huimin 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2017年第S1期267-268,共2页
1 Introduction The howardite,eucrite and diogenite(HED)meteorites are ultramafic and mafic igneous rocks and impact-engendered breccias derived from a thoroughly differentiated asteroid 4 Vesta.Diogenites include duni... 1 Introduction The howardite,eucrite and diogenite(HED)meteorites are ultramafic and mafic igneous rocks and impact-engendered breccias derived from a thoroughly differentiated asteroid 4 Vesta.Diogenites include dunites, 展开更多
关键词 Co Siderophile element Compositions of Pyroxenes in HED Meteorites Implications for the Differentiation of Magma Ocean on Vesta
下载PDF
Predictions of elemental composition of coal and biomass from their proximate analyses using ANFIS, ANN and MLR 被引量:1
10
作者 Abiodun Ismail Lawal Adeyemi Emman Aladejare +2 位作者 Moshood Onifade Samson Bada Musa Adebayo Idris 《International Journal of Coal Science & Technology》 EI CAS CSCD 2021年第1期124-140,共17页
The elemental composition of coal and biomass provides significant parameters used in the design of almost all energy conversion systems and projects.The laboratory tests to determine the elemental composition of coal... The elemental composition of coal and biomass provides significant parameters used in the design of almost all energy conversion systems and projects.The laboratory tests to determine the elemental composition of coal and biomass is time-consuming and costly.However,limited research has suggested that there is a correlation between parameters obtained from elemental and proximate analyses of these materials.In this study,some predictive models of the elemental composition of coal and biomass using soft computing and regression analyses have been developed.Thirty-one samples including parameters of elemental and proximate analyses were used during the analyses to develop multiple prediction models.Dependent variables for multiple prediction models were selected as carbon,hydrogen,and oxygen.Using volatile matter,fixed carbon,moisture and ash contents as independent variables,three different prediction models were developed for each dependent parameter using ANFIS,ANN,and MLR.In addition,a routine for selecting the best predictive model was suggested in the study.The reliability of the established models was tested by using various prediction performance indices and the models were found to be satisfactory.Therefore,the developed models can be used to determine the elemental composition of coal and biomass for practical purposes. 展开更多
关键词 BIOMASS COAL elemental composition Proximate analysis Soft computing Regression analysis
下载PDF
In-situ LA-ICP-MS trace element and oxygen isotope signatures of magnetite from the Yamansu deposit,NW China,and their significance 被引量:1
11
作者 Zhiyuan Sun Yuwang Wang Lingli Long 《Acta Geochimica》 EI CAS CSCD 2020年第5期599-615,共17页
The Yamansu iron deposit is hosted in submarine volcanic rocks in the Aqishan–Yamansu belt of Eastern Tianshan,NW China.A geological cross-section for the Carboniferous strata in the ore district shows that ore bodie... The Yamansu iron deposit is hosted in submarine volcanic rocks in the Aqishan–Yamansu belt of Eastern Tianshan,NW China.A geological cross-section for the Carboniferous strata in the ore district shows that ore bodies in the Yamansu deposit are hosted in andesitic crystal tuff of the third cycle of the Carboniferous Yamansu Formation.This indicates an association between mineralization and volcanism.The orebodies are strata bound and lensoid and generally share the occurrence state of the host rocks.Magnetite mineralization mainly occurs asbreccia ores,ores in the mineralized volcanic rocks,massive ores,and sulfide-rich ores according to their structures and sequences of formation.Trace element compositions of magnetite from various types of ores were determined by LA-ICP-MS.The dataset indicates thatdifferent types of magnetite havedistinct trace element contents correlated to their formation environments.Magnetite crystals from breccia ores have high Ti,Ni,V,Cr,and Co and low Si,Al,Ca,and Mg contents,indicating crystallization from a volcanic magmatic eruption,which is consistent with field evidence of coexisting altered volcanic breccia.Magnetite crystals from ores in the mineralized volcanic rocks have moderate Ti,Ni,V,Cr,and Co contents.In contrast,magnetite from massive ores and sulfide-rich ores have low concentrations of Ti,Cr,Ni,and V,high concentrations of Si,Al,Ca,and Mg,and evidence of hydrothermal magnetite.In-situ magnetite compositions imply a magmatic-hydrothermal process.Although d18 O values for magnetite grains from Yamansu vary(?1.3 to?7.0%),they all plot in the range field of volcanic iron deposits,and they also record a magmatic-hydrothermal process.The compositions of Yamansu magnetites are interpreted as controlled mainly by temperature,fluid,host rock buffering,oxygen fugacity,and sulfur fugacity.The metallogenic conditions of the Yamansu deposit changed from high temperature and low oxygen fugacity to low temperature and high oxygen fugacity.However,more fluid-rock reactions and higher sulfur fugacity were involved during the deposition of massive ores and sulfiderich ores. 展开更多
关键词 MAGNETITE Trace element composition LAICP-MS Oxygen isotope Yamansu iron deposit Eastern Tianshan
下载PDF
Determination of element composition of three lichens and their distribution in King George Island, Antarctica 被引量:1
12
作者 李永良 周云龙 张正旺 《Chinese Journal of Polar Science》 2000年第2期141-146,共6页
Cross-section slices of Usnea antarctica Du Rietz, Usnea aurantiaco-atra (Jacq.) Bory. and Cladonia sp. at upper, middle and basal positions were prepared, respectively. The element composition and relative... Cross-section slices of Usnea antarctica Du Rietz, Usnea aurantiaco-atra (Jacq.) Bory. and Cladonia sp. at upper, middle and basal positions were prepared, respectively. The element composition and relative content were determined by SEM and EDS at the surface, intermediate and inner layers in each slice, respectively. The result indicated that the composition of element is mostly same in these lichens. The relative content of Al, Si, K and Ca elements is high,and P is close at each position. The result is of benefit to study the structure and physiological characteristics of lichens, and to analyze geological environment in Antarctica. 展开更多
关键词 ANTARCTICA LICHEN element composition distribution.
下载PDF
Structural Performance of Light Weight Multicellular FRP Composite Bridge Deck Using Finite Element Analysis 被引量:1
13
作者 Woraphot Prachasaree Pongsak Sookmanee 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2012年第5期939-943,共5页
Fiber reinforced polymer (FRP) composite materials having advantages such as higher strength to weight than conventional engineering materials, non-corrosiveness and modularization, which should help engineers to ob... Fiber reinforced polymer (FRP) composite materials having advantages such as higher strength to weight than conventional engineering materials, non-corrosiveness and modularization, which should help engineers to obtain more efficient and cost effective structural materials and systems. Currently, FRP composites are becoming more popular in civil engineering applications. The objectives of this research are to study performance and behavior of light weight multi-cellular FRP composite bridge decks (both module and system levels) under various loading conditions through finite element modeling, and to validate analytical response of FRP composite bridge decks with data from laboratory evaluations. The relative deflection, equivalent flexural rigidity, failure load (mode) and load distribution factors (LDF) based on FE results have been compared with experimental data and discussed in detail. The finite element results showing good correlations with experimental data are presented in this work. 展开更多
关键词 fiber reinforced polymer (FRP) composites bridge deck finite element
下载PDF
GLOBAL COMPOSITE ELEMENT ITERATION FOR ANALYSIS OF SEEPAGE FREE SURFACE
14
作者 陈洪凯 唐红梅 肖盛燮 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 1999年第10期1121-1127,共7页
As one of the most difficult topics in rock mass hydromechanics, seepage free surface plays an important part in slope stability researches. Based on analysis of numerical methods to solve seepage free surface, global... As one of the most difficult topics in rock mass hydromechanics, seepage free surface plays an important part in slope stability researches. Based on analysis of numerical methods to solve seepage free surface, global composite element iteration (GCEI) is presented in this paper. FEM program is made by using GCEI. Calculation shows that not only the program is simple using GCEI, but also the tolerance is higher after 5 iterations. 展开更多
关键词 rock mass slope seepage free surface global composite element iteration verification
下载PDF
Elemental Composition Method in Thermodynamics of Multireaction Systems (II) Residual Properties, Property Changes of Mixing and Excess Properties Relations
15
作者 林金清 李浩然 韩世钧 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2002年第4期464-468,共5页
Based on the concept of “element” and the fundamental thermodynamic principle,the relationships of the residual properties,the property changes of mixing,excess properties,fugacity coefficients and activity coeffici... Based on the concept of “element” and the fundamental thermodynamic principle,the relationships of the residual properties,the property changes of mixing,excess properties,fugacity coefficients and activity coefficients between the hypothetical solution of elemental species and the equilibrated solution of actual species were established.The hypothetical solution of elemental species provides a way of reducing the dimensionality of problem, simplifying the analysis and visualizing the phase behavior. 展开更多
关键词 elemental composition dimension reduction multireaction phaseequilibrium
下载PDF
Zircon Mineralogy and Trace Elements Composition of the Metallogenic Granites in the Nanshankeng Mine,Eastern Nanling
16
作者 FAN Feipeng XIAO Huiliang +3 位作者 CHEN Lezhu LI Haili CAI Yitao ZHOU Yan 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2017年第S1期78-79,共2页
1 Introduction Nanshankeng tungsten-tin polymetallic mine,which is located in the eastern Nanling metallogenic belt,is newly discovered by geological investigation and evaluation with prospecting potential(Xiao et
关键词 Th Zircon Mineralogy and Trace elements Composition of the Metallogenic Granites in the Nanshankeng Mine Eastern Nanling BSE
下载PDF
A Study of Changes in the Element Composition and Structure of Surfaces under Irradiation of Dense Xenon Gas (270 bar) by y-Rays with a Maximum Energy of 10 MeV
17
作者 A. Yu. Didyk G. G. Gulbekian +1 位作者 G. V. Mishinskiy R.Wisniewski 《Journal of Physical Science and Application》 2016年第2期18-28,共11页
A high-pressure chamber filled with natural xenon (XeHPC) under initial pressure 270 bar was irradiated during 43 hours by braking γ-rays with a maximum energy of 10 MeV at the MT-25 electron accelerator at an aver... A high-pressure chamber filled with natural xenon (XeHPC) under initial pressure 270 bar was irradiated during 43 hours by braking γ-rays with a maximum energy of 10 MeV at the MT-25 electron accelerator at an average beam intensity of 20-22 μA. After about 14 hours of irradiation, the pressure in the XeHPC dropped to 185 bar and did not change till the end of the irradiation cycle. Upon completion of exposure, part of the gas from XeHPC was bypassed into a separate reservoir to measure the xenon composition by mass-analyzer QMA-200. After the opening of the XeHPC, an inner assembly without xenon was fixed at the Ge-detector for measurement of γ-spectra of radionuclides produced in the XeHPC and the background during 15 hours. A visual inspection of the inner assembly indicated that the surfaces of its elements were covered with a siskin green layer. Using SEM (scanning electron microscopy) studies and MPRA (microprobe roentgen analysis) , the element compositions of the synthesized micro-objects and micro-particles were determined. In order to explain the observed anomalies in the formation of new elements in the micro-particles and micro-objects, nuclear fission and synthesis reactions should be used. 展开更多
关键词 element composition structure IRRADIATION XENON γ-rays maximum energy.
下载PDF
Calibration of Discrete Element Heat Transfer Parameters by Central Composite Design 被引量:1
18
作者 Zongquan DENG Jinsheng CUI +1 位作者 Xuyan HOU Shengyuan JIANG 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2017年第2期419-427,共9页
The efficiency and precision of parameter calibration in discrete element method (DEM) are not satisfactory, and parameter calibration for granular heat transfer is rarely involved. Accordingly, parameter calibratio... The efficiency and precision of parameter calibration in discrete element method (DEM) are not satisfactory, and parameter calibration for granular heat transfer is rarely involved. Accordingly, parameter calibration for granular heat transfer with the DEM is studied. The heat transfer in granular assemblies is simulated with DEM, and the effective thermal conductivity (ETC) of these granular assemblies is measured with the transient method in simulations. The measurement testbed is designed to test the ETC of the granular assemblies under normal pressure and a vacuum based on the steady method. Central composite design (CCD) is used to simulate the impact of the DEM parameters on the ETC of granular assemblies, and the heat transfer parameters are calibrated and compared with experimental data. The results show that, within the scope of the considered parameters, the ETC of the granular assemblies increases with an increasing particle thermal conductivity and decreases with an increasing particle shear modulus and particle diameter. The particle thermal conductivity has the greatest impact on the ETC of granular assemblies followed by the particle shear modulus and then the particle diameter. The calibration results show good agreement with the experimental results. The error is less than 4%, which is within a reasonable range for the scope of the CCD parameters. The proposed research provides high efficiency and high accuracy parameter calibration for granular heat transfer in DEM. 展开更多
关键词 Granular assembly · Parameter calibration · Effective thermal conductivity (ETC) · Discrete element method (DEM) · Central composite design (CCD) · Vacuum
下载PDF
The finite element analysis of articular cartilage fiber-reinforced composite model under rolling load
19
作者 Qin Xiao-feng,Liu Hai-ying,Ye Jin-duo,Zhang Chun-qiu(School of Mechanical Engineering,Tianjin University of Technology,Tianjin 300384) 《医用生物力学》 EI CAS CSCD 2009年第S1期67-67,共1页
Articular cartilage is a layer of low-friction,load-bearing soft hydrated tissue covering bone-ends in diarthrosis,which plays an important role in spreading the load,reducing the joint contact stress,joint friction a... Articular cartilage is a layer of low-friction,load-bearing soft hydrated tissue covering bone-ends in diarthrosis,which plays an important role in spreading the load,reducing the joint contact stress,joint friction and wear during exercise.The vital mechanical function 展开更多
关键词 The finite element analysis of articular cartilage fiber-reinforced composite model under rolling load
下载PDF
Effect of Surface Treatment on Elemental Composition of Recast NiCr Alloy
20
作者 Tevfik Yavuz Asli Acar +1 位作者 Serhan Akman Atiye Nilgun Ozturk 《Materials Sciences and Applications》 2012年第3期163-167,共5页
Objective: The aim of this study was to compare the effects of different surface treatments on the elemental composition stability of as-received and recast types of NiCr casting alloys. Material and Methods: Six comm... Objective: The aim of this study was to compare the effects of different surface treatments on the elemental composition stability of as-received and recast types of NiCr casting alloys. Material and Methods: Six commercial NiCr dental casting alloys (Kera N, Nodelco, Bellabond, Wiron 99, Metaplus VK, and Tritech D) were used in this study. Seventy-two specimens (12 × 12 × 1.2 mm) were produced using the lost-wax casting process. Three casting protocols were established in relation to the proportion of as-received and recast alloys: Group A (100% as-received metal), Group B (50 wt% new metal, 50 wt% once-recast metal), and Group C (100% once-recast metal). Two specimens in every group received two different surface treatments: sandblasting with 110 μmm Al2O3 or oxidation firing. An elemental analysis was performed with x-ray energy-dispersive spectroscopy. Results were subjected to one-way analysis of variance and Tukey HSD tests. Results: The elemental composition was significantly different in the casting groups and treatment groups (p < 0.05). The lowest mean weight percentage Ni value was recorded for Group C and the highest for Group A. Aluminum-oxide sandblasting of the alloy surface reduced the mean weight percentage for Cr. Conclusion: Recasting metal alloys may adversely affect surface quality. 展开更多
关键词 Recasting elemental Composition NiCr Alloy
下载PDF
上一页 1 2 4 下一页 到第
使用帮助 返回顶部