检索结果-南通市图书馆

Particuology 2024年第5期88卷 116-127页

作者： Zhilong Wang Zhenzhen Zhao ye Yang An Zhang Xiayi liu Tong Zhao Yahui Cui School of Mechanical and Precision Instrument Engineering Xi'an University of TechnologyXi'an 710048China

This paper presents the effects of both poly vinylidene fluoride(PVDF)/carbon black(CB)ratio(m PVDF:m CB)and mixing time t on the dispersion mechanism of the cathode slurry of lithium-ion battery(LIB).The dispersion mechanism is deduced from the electrochemical,morphological and rheological properties of the cathode slurry by using electrical impedance spectroscopy(EIS),scanning electron microscopy and rheology methods,respectively.From the perspective of EIS method,static simulation models are established in the COMSOL Multiphysics software;meanwhile,the simulated results are used to verify the correctness of the electrochemical properties of the cathode slurry.As a result,the following conclusions are able to be obtained.Firstly,in the case of the mass ratio m PVDF:m CB=5:10,LiCoO2 particles are completely coated by the mixture of CB and PVDF to form a stable polymer gel structure.Higher or lower m PVDF:m CB leads to the larger impedance and worse dispersion status for the cathode slurry.Secondly,when t=6 min,a good gel-like conductive network structure is formed by coating the thinner evenly dispersed CB–PVDF double layer around LiCoO2 particles.Finally,a strategy regarding to both m PVDF:m CB and t in experimental scale is proposed,which has the capability of improving the performance of LIB.

关键词： Cathode slurry Dispersion mechanism Lithium-ion battery(LIB)

980 nm Near-Infrared Light-Emitting Diode Using All-Inorganic Perovskite Nanocrystals Doped with Ytterbium Ions

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Tsinghua Science and Technology 2024年第1期29卷 207-215页

作者： Zhenglan ye Taoran liu Dan Chen Yazhou Yang Jiayi Li Yaqing Pang Xiangquan liu Yuhua Zuo Jun Zheng Zhi liu Buwen Cheng State Key Laboratory on Integrated Optoelectronics Institute of SemiconductorsChinese Academy of SciencesBeijing 100083China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049China Intelligent Network Research Institute Zhejiang LabHangzhou 311100China

All-inorganic perovskite(CsPbX3)nanocrystals(NCs)have recently been widely investigated as versatile solution-processable light-emitting materials.Due to its wide-bandgap nature,the all-inorganic perovskite NC Light-Emitting Diode(LED)is limited to the visible region(400-700 nm).A particularly difficult challenge lies in the practical application of perovskite NCs in the infrared-spectrum region.In this work,a 980 nm NIR all-inorganic perovskite NC LED is demonstrated,which is based on an efficient energy transfer from wide-bandgap materials(CsPbCl3 NCs)to ytterbium ions(Yb3+)as an NIR emitter doped in perovskite NCs.The optimized CsPbCl3 NC with 15 mol%Yb3+doping concentration has the strongest 980 nm photoluminescence(PL)peak,with a PL quantum yield of 63%.An inverted perovskite NC LED is fabricated with the structure of ITO/PEDOT:PSS/poly-TPD/CsPbCl3:15 mol%Yb3+NCs/TPBi/LiF/Al.The LED has an External Quantum Efficiency(EQE)of 0.2%,a Full Width at Half Maximum(FWHM)of 47 nm,and a maximum luminescence of 182 cd/m?.The introduction of Yb3+doping in perovskite NCs makes it possible to expand its working wavelength to near-infrared band for next-generation light sources and shows potential applications for optoelectronic integration.

关键词： perovskite nanocrystals rare-earth doping Light-Emitting Diode(LED) near-infrared optical interconnection

Effect of Sintering Temperature on the Microstructure and Mechanical Properties of Nanocrystalline Cemented Carbide

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Wuhan University of Technology(Materials Science) 2024年第3期39卷 664-672页

作者：陈先富刘颖 ye Jinwen WANG Lu School of Materials Science and Engineering Sichuan UniversityChengdu 610065China Key Laboratory of Advanced Special Ma-terial&Technology Ministry of EducationChengdu 610065China

WC-Co nanocrystalline nitrogen-containing cemented carbides were prepared by vacuum sintering and low pressure sintering.The sintering processes of Cr_(2)(C,N)doped nano WC-Co powders were studied by using thermogravimetric analysis(TGA)and differential scanning calorimetry(DSC).The effect of sintering temperature on the microstructure and mechanical properties of nanocrystalline cemented carbide was studied by scanning electron microscope(SEM),high resolution transmission electron microscope(HRTEM)and mechanical property test.The results showed that the nano WC grains began to grow in the solid phase sintering stage.A high-performance nano-nitrogen-containing cemented carbide with uniform microstructure and good interfacial bonding can be obtained by increasing the sintering temperature to 1380℃.It has a transverse rupture strength(TRS)of 5057 MPa and a hardness of 1956 HV30.

关键词： nano nitrogen cemented carbide sintering temperature microstructure mechanical properties

维普期刊数据库

Strong Antiferromagnetic Exchange-Coupling Observed in Hydride-Bridged Dimeric Dysprosium(Ⅲ)Single-Molecule Magnet

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemistry 2024年第4期42卷 391-396页

作者： Qian-Cheng Luo Ke-Xin Yu Peng-Bo Jin ye-ye liu Yuan-Qi Zhai Yan-Zhen Zheng Frontier Institute of Science and Technology State Key Laboratory of Electrical Insulation and Power EquipmentXi'an Key Laboratory of Electronic Devices and Materials ChemistrySchool of Chemistry and School of PhysicsXi'an Jiaotong University99 Yanxiang RoadXi'anShaanxi710054 China

One dihydride-bridged dimeric Dy(Ⅲ)guanidinate complex,formulated as[{(Me_(3)Si)_(2)NC(NiPr)_(2)}_(2)Dy(μ-H)]_(2)(1Dy),was successfully isolated and the introduction of hydride bridges significantly reduces the intramolecular Dy(Ⅲ)…Dy(Ⅲ)distance to only 3.688(1)Å.To investigate the effect of such a short Dy(Ⅲ)…Dy(Ⅲ)distance on magnetism,we also prepared its dibromide-bridged analogue[{(Me_(3)Si)_(2)NC(NiPr)_(2)}_(2)Dy(μ-Br)]_(2)(2Dy),which has a much longer Dy(Ⅲ)…Dy(Ⅲ)distance of 4.605(4)Å.Surprisingly,2Dy demonstrates much larger effective energy barrier for magnetization reversal(U_(eff))and higher blocking temperature(T_(B)).The worse performance of 1Dy is attributed to the concerted effect of strong antiferromagnetic interactions between Dy(Ⅲ)ions(J_(total)=–2.683 cm^(–1))and the unparallel arrangement of magnetic principle axes of the Dy(Ⅲ)ions for 1Dy.

关键词： Single-molecule magnets Lanthanides Guanidinate ligand Hydride bridge Magnetic properties Ab initio calculations

Flow characterization of macroporous W-4.8 vol.%ZrO2 alloy during hot deformation with improved constitutive equation and processing maps

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Tungsten 2024年第3期6卷 610-620页

作者： Jia-Hao ye liu-Jie Xu Ji-Kang Hu School of Materials Science and Engineering Henan University of Science and Technology National Joint Engineering Research Center for Abrasion Control and Molding of Metal Materials Henan University of Science and Technology

In this work,isothermal compression experiments of macroporous W-4.8 vol.%ZrO2（W-4.8ZrO2） at 1300-1600℃ and strain rate of 0.005-1 s-1were carried out on a Gleeble-1500D thermo-mechanical simulator.The dynamic recovery of W-4.8ZrO2is the main "softening" mechanism.On the basis of Arrhenius model,the initial constitutive equation is established by exploring the influence of temperature,strain rate and rheological stress.Based on Arrhenius model,the relationship between flow stress,strain rate and deformation temperature is established.Considering the influence of strain,the improved constitutive equation and the law of material constant changing with the strain are obtained.After that,the hot processing maps were drawn on the basis of the dynamic material model,which is used to analyze the instability mechanism of the W-4.8ZrO2,and determine the appropriate hot working process parameters(temperature:1350-1450℃,strain rate:0.1-1 s-1).

关键词： Tungsten alloy Flow characteristics Constitutive equation Hot processing maps

Study on preparation,characterization and application of mixed-colorants thermochromic microcapsules

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Particuology 2024年第5期88卷 89-97页

作者： Lan Zhou Jingpeng ye Qinze Cai Guojin liu Mehran Dadgar Guocheng Zhu Guoqing Zhang College of Textile Science and Engineering (International Institute of Silk) Zhejiang Sci-Tech UniversityHangzhou310018China School of Materials Science& Engineering Zhejiang Sci-Tech UniversityHangzhou310018China Department of Textile University of NeyshaburAdib BoulevardKhorasan Razavi ProvinceIran Zhejiang Charming Dyeing and Finishing Co. LtdJiaxing314500China Zhejiang Provincial Innovation Center of Advanced Textile Technology Shaoxing312000China

In order to expand the color-change range and make the discoloration temperature suitable for the daily textiles,a new formulation of mixed-colorants thermochromic core material is designed,in which crystal violet lactone(CVL)is the basic color former,bisphenol A(BPA)is the developer,especially the solvent-based dye and dodecyl dedecanoate are used as the extended dye and the solvent,respectively.Scanning electron microscope(SEM),differential scanning calorimeter(DSC)and thermogravimetric analyzer(TGA)were applied to study the morphology,encapsulation rate,non-isothermal crystallization behavior and thermal stability of the mixed-colorant thermochromic microcapsules(MCTMs)prepared by in-situ polymerization.The results show that MCTMs have good sphericity,uniform particle size,good thermal stability and the encapsulation rate can reach 86.73%.Under the non-isothermal conditions,the encapsulation of formaldehyde-melamine resin wall material can slightly reduce the crystallization rate of the solvent,but does not affect the relative crystallinity,thermal properties and discoloration sensitivity of the core materials.With the variety of ambient temperatures in the range of 20–35°C,the printed cotton fabrics with MCTMs could change color reversibly between different tones with good reliability and durability,and exhibit more gorgeous colors than the common thermochromic materials.

关键词： Thermochromic microcapsule Color-change range Phase-change material Crystallization behavior

Mechanical properties and thermal deformation behavior of low-cost titanium matrix composites prepared by a structure-optimized Y_(2)O_(3) crucible

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research(International) 2024年第3期31卷 738-751页

作者： Qian Dang Gang Huang ye Wang Chi Zhang Guo-huai liu Zhao-dong Wang The State Key Laboratory of Rolling and Automation Northeastern UniversityShenyang 110819LiaoningChina School of Materials Science and Chemical Engineering Harbin University of Science and TechnologyHarbin 150004HeilongjiangChina School of Materials Science and Engineering Shenyang University of TechnologyShenyang 110870LiaoningChina

A porous yttrium oxide crucible with both thermal shock resistance and erosion resistance was developed by structural optimization.The structure-optimized yttrium oxide crucible was proved to be suitable for melting highly reactive titanium alloys.Low-cost(TiB+Y2O_(3))-reinforced titanium matrix composites were prepared by vacuum induction melting using the prepared crucible.The thermal deformation behavior and microstructure evolution of(TiB+Y2O_(3))-reinforced tita-nium matrix composites were investigated at deformation temperatures of 900-1100℃with strain rates of 0.001-1 s-1.The results showed that the prepared yttrium oxide crucible had both thermal shock and erosion resistance,the low-cost titanium matrix composites could be prepared by the developed yttrium oxide crucibles which were homogeneous in composition and highly sensitive to strain rate and deformation temperature,and the peak and theological stresses decreased with increasing deformation temperature or decreasing strain rate.In addition,the average thermal deformation activation energy of the composites was calculated to be 574.6 kJ/mol by establishing the Arrhenius constitutive equation in consideration of the strain variables,and the fitting goodness between the predicted stress value and the measured value was 97.624%.The calculated analysis of the hot processing map showed that the best stable thermal deformation zone was located in the deformation temperature range of 1000-1100℃and strain rate range of 0.001-0.01 s^(-1),where the peak dissipation coefficient wasη=71%.In this zone,the deformation of the reinforcement and matrix was harmonious,the reinforcement was less likely to fracture,dynamic recrystallization occurred more fully and the alloy exhibited near steady rheological characteristics.

关键词： Yttrium oxide crucible Titanium matrix composite Thermal deformation behavior Constitutive equation Hot processing map Microstructure evolution

Dynamic Effect of Landslides Triggered by Earthquake:A Case Study in Moxi Town of Luding County,China

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Earth Science 2024年第1期35卷 221-234页

作者： Hongfu Zhou Fei ye Wenxi Fu Bin liu Tian Fang Rui Li Chengdu Center China Geological SurveyChengdu 610081China State Key Laboratory of Hydraulics and Mountain Rivers Protection Sichuan UniversityChengdu 610065China Sichuan Geological Survey Chengdu610081China Shandong University of Science and Technology Qingdao 266590China

The dynamic effect is a very important issue widely debated by scholars when studying the genetic and disaster-causing mechanisms of earthquake-triggered landslides.First,the dynamic effect mechanism and phenomena of earthquake-triggered landslides were summarized in this paper.Then,the primary types of dynamic effects were further used to interpret the Mogangling landslide in Moxi Town of Luding County,China.A field investigation,remote sensing,numerical calculation and theoretical analysis were carried out to illustrate the failure mechanism of slope rock masses affected by earthquakes.The interaction between seismic waves and slope rock masses and the induced dynamic effect of slope rock masses were primarily accounted for in the analysis.The slope topography,rock mass weathering and unloading characteristics,river erosion,regional seismogenic structure,and rock mass structure characteristics were also discussed.The results showed that the formation of the Mogangling landslide was mainly related to the high amplification effect of seismic acceleration and back slope effects,interface dynamic stress effects,and double-sided slope effects of seismic waves caused by the catastrophic Ms 7.75 Moxi Earthquake in 1786.The principles for the site and route selection of large-scale infrastructure in the planning stage and the scientific prevention of seismic geological disasters were proposed on the basis of the dynamic effect of earthquake-induced landslides.

关键词： dynamic effect coupling of endogenic and exogenic processes landslides earthquakes disaster prevention

维普期刊数据库

Chemical composition and pharmacological activity of seco-prezizaane-type sesquiterpenes

在线全文

学校读者我要写书评

暂无评论

Chinese Herbal Medicines 2024年第1期16卷 70-81页

作者： ye Jin Yanqing Xie Peng Zhang Afsar Khan Zhihong Zhou Lu liu Yunnan Yunzhong Institute of Nutrition and Health Yunnan University of Chinese MedicineKunming 650500China Department of Chemistry COMSATS University IslamabadAbbottabad CampusAbbottabad 22060Pakistan

The seco-prezizaane-type sesquiterpenes(SPS),as a special class of sesquiterpenes with a highly oxidative five-ring cage structure and seven consecutive chiral centers,are isolated from the genus Illicium,which have a variety of biological activities,including neurotoxicity and neurotrophic effects,etc.This review summarizes the chemical constituents and pharmacological effects of SPS,and discusses the potential trend and scope of future research.

关键词： anisatin chemical composition Illicium genus majucin pharmacological activity seco-prezizaane-type sesquiterpenes

维普期刊数据库

Investigation of the block toppling evolution of a layered model slope by centrifuge test and discrete element modeling

在线全文

学校读者我要写书评

暂无评论

Journal of Rock Mechanics and Geotechnical Engineering 2024年第1期16卷 112-122页

作者： Leilei Jin Hongkai Dong Fei ye Yufeng Wei Jianfeng liu Changkui Wang State Key Laboratory of Hydraulic and Mountain River Engineering College of Water Resource and HydropowerSichuan UniversityChengdu610065China State Key Laboratory of Geohazard Prevention and Geoenvironment Protection Chengdu University of TechnologyChengdu610059China

Primary toppling usually occurs in layered rock slopes with large anti-dip angles.In this paper,the block toppling evolution was explored using a large-scale centrifuge system.Each block column in the layered model slope was made of cement mortar.Some artificial cracks perpendicular to the block column were prefabricated.Strain gages,displacement gages,and high-speed camera measurements were employed to monitor the deformation and failure processes of the model slope.The centrifuge test results show that the block toppling evolution can be divided into seven stages,i.***.layer compression,formation of major tensile crack,reverse bending of the block column,closure of major tensile crack,strong bending of the block column,formation of failure zone,and complete failure.Block toppling is characterized by sudden large deformation and occurs in stages.The wedge-shaped cracks in the model incline towards the slope.Experimental observations show that block toppling is mainly caused by bending failure rather than by shear failure.The tensile strength also plays a key factor in the evolution of block toppling.The simulation results from discrete element method(DEM)is in line with the testing results.Tensile stress exists at the backside of rock column during toppling deformation.Stress concentration results in the fragmented rock column and its degree is the most significant at the slope toe.

关键词： Block toppling Centrifuge Anti-dip slope Failure mechanism Discrete element method