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Aging resistance and mechanical properties of Sn3.0Ag0.5Cu solder bump joints with different bump shapes

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Rare Metals 2021年第1期40卷 225-230页

作者： Ping chen Xiu-chen Zhao Ying Liu Hong Li yong wang School of Materials Science and Engineering Beijing Institute of TechnologyBeijing 100081China Center of Packaging and Testing Beijing Microelectronics Technology InstituteBeijing 100076China

The effects of bump shape on the aging resistance and mechanical properties of Sn3.0 Ag0.5 Cu(SAC)solder bump joints were investigated by high-temperature aging test and shear test.Three different SAC solder bump joints with barrel type,cylinder type,and hourglass type,respectively,were provided by controlling solder process.The results indicate that as the bump volume decreases from barrel bump to hourglass bump in the reflow,the thickness growth rate of intermetallic compounds(IMCs)between different solder joints and Cu substrates in the isothermal aging of 150℃decreases.And the change of shear strength of hourglass interconnection solder joint with the increase in temperature is the minimum in the three interconnection solder joints.Thus,as the solder dosage decreases properly,hourglass interconnection solder joint is obtained,which is avail to enhance the solder joint reliability at the high-temperature aging and the ability to adapt to the change of environment temperature suddenly.

关键词： Bump shape Lead-free solder Intermetallic compounds Mechanical properties

Microstructure,Mechanical Properties,and Corrosion Behavior of Mg-Al-Ca Alloy Prepared by Friction Stir Processing

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Acta Metallurgica Sinica(English Letters) 2022年第5期35卷 703-713页

作者： Wen wang Shan-yong chen Ke Qiao Pai Peng Peng Han Bing Wu chen-Xi wang Jia wang Yu-Hao wang Kuai-She wang School of Metallurgical Engineering National and Local Joint Engineering Research Center for Functional Materials ProcessingXi’an University of Architecture and TechnologyXi’an710055China

Friction stir processing(FSP)was used to modify the microstructure and improve the mechanical properties and corrosion resistance of an Mg-Al-Ca alloy.The results demonstrated that,after FSP,the grain size of the Mg-Al-Ca alloy was decreased from 13.3 to 6.7μm.Meanwhile,the Al_(8)Mn_(5) phase was broken and dispersed,and its amount was increased.The yield strength and ultimate tensile strength of the Mg-Al-Ca alloy were increased by 17.0%and 10.1%,respectively,due to the combination of fine grain,second phase,and orientation strengthening,while the elongation was slightly decreased.The immersion and electrochemical corrosion rates in 3.5 wt%NaCl solution decreased by 18.4%and 37.5%,respectively,which contributed to grain refinement.However,the stress corrosion cracking(SCC)resistance of the modified Mg-Al-Ca alloy decreased significantly,which was mainly due to the filiform corrosion induced by the Al_(8)Mn_(5) phase.SCC was mainly controlled by anodic dissolution,while the cathodic hydrogen evolution accelerated the SCC process.

关键词： Friction stir processing Mg-Al-Ca alloy Second phase Mechanical properties Stress corrosion cracking

Seismic airgun exploration of continental crust structures

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Science China Earth Sciences 2017年第10期60卷 1739-1751页

作者： chen yong wang BaoShan YAO HuaJian School of Earth Sciences and Engineering Nanjing University Nanjing 210046 China Institute of Earthquake Science China Earthquake Administration Beijing 100036 China Key Laboratory of Seismic Observation and Geophysical Imaging Institute of Geophysics China Earthquake Administration Beijing 100081 China Laboratory of Seismology and Physics of Earth's Interior School of Earth and Space Sciences University of Science and Technology of China Hefei 230026 China National Geophysical Observatory at Mengcheng University of Science and Technology of China Hefei 230026 China

The active sources generate seismic waves transmitting appropriate through the deep is underground key and can be used to image Abstract high-resolution subsurface structures.Therefore,an seismic source the factor to active source exploration.In order to study the structure of continental crust and its temporal variations,we selected an artificial seismic source generated from releasing air bubbles in water(airgun source hereinafter)out of a variety and of artificial sources like the is explosion,new electronic sparkers,source hammering,eccentric proven vibration,be heavy-duty train vibration,vibroseis etc.Airgun Three source Fixed a type of artificial that have been to environmentally friendly,safe,and highly efficient.Airgun western Signal China Transmission and Stations(FASTS)have been for built a few years ago in Yunnan,Xinjiang,and Gansu provinces in have been continuously them running several years.Seismic waves generated away by the the airgun sources are highly seismic reproducible waves and stacking in of can produce can good seismograms on 1300 stations km far from source,for instance,an produced Xinjiang FASTS be well about recorded 60 nearly away after 5000 stacking,China covering area of 6 million km2 and penetrating down to of a depth of km.Establishing about 10 FASTSs in would enable long-term illuminate continuous subsurface underground structures,monitoring can all 9.6 million km2 of land area.Treating from airgun sky active sources as lanterns to we achieve the situation with"Beidou surveys the and lantern illuminates underground".

关键词：气枪震源地壳结构地震波探测大陆地下结构人工震源土地面积

Hydrothermal-treated Pt/Al_(2)O_(3) as an excellent catalyst for toluene total oxidation

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Journal of Environmental Sciences 2022年第6期34卷 114-124页

作者： Xiao chen yong wang Jianyu Li Zhongheng Hu Ying Zhou Huayan Liu Hanfeng Lu Institute of Catalytic Reaction Engineering College of Chemical EngineeringZhejiang University of TechnologyHangzhou 310014China

The preparation of highly active supported noble metal catalysts with a low noble metal loading has always been the ultimate goal of researchers working on catalysis.Hydrothermally treated Pt/Al_(2)O_(3)(Pt/Al_(2)O_(3)-H)exhibits better catalytic activity than that(Pt/Al_(2)O_(3)-C)treated via the conventional calcination approach.At the high space velocity of100,000 m L/(g·hr),the temperature that correspond to 50%toluene conversion(T50)of Pt/Al_(2)O_(3)-H is 115℃ lower than that of Pt/Al_(2)O_(3)-C,and the turnover frequency(TOF)value can reach 0.0756 sec-1.The mechanism by which the hydrothermal approach enhances Pt/Al_(2)O_(3) activity has been investigated.The structure associated with the high catalytic activity of Pt nanoparticles(NPs)can be retained via hydrothermal treatment.Furthermore,the support is transformed to AlO(OH)with numerous surface hydroxyl groups,which in turn can facilitate the adsorption of toluene.And the synergistic effects of Pt NPs and AlO(OH)increases the contents of Pt in oxidation state and active oxygen,which are beneficial for toluene oxidation.

关键词： Pt/Al_(2)O_(3) Calcination activation Hydrothermal activation AlO(OH) Catalytic combustion of toluene

Alkyl-modified nucleobases with 6/5/7/5 ring systems from the insect Cyclopelta parva

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Organic Chemistry Frontiers 2022年第1期9卷 75-80页

作者： yong-Ming Yan Heng chen Wen-Long chen Dai-Wei wang Li Liao Qing Lu yong-Xian cheng Institute for Inheritance-Based Innovation of Chinese Medicine Marshall Laboratory of Biomedical EngineeringSchool of Pharmaceutical SciencesHealth Science CenterShenzhen UniversityShenzhen 518060PR China Guangdong Key Laboratory for Functional Substances in Medicinal Edible Resources and Healthcare Products School of Life Sciences and Food EngineeringHanshan Normal UniversityChaozhou 521041PR China

(±)-Cyclopeltains A and B(1 and 2),two pairs of unusual alkylated adenine derivatives,were isolated from the insect Cyclopelta parva and structurally characterized.1 and 2 both possess a 6/5/7/5 ring system arising from the alkylation of N^(7) and N^(10) by a C6 unit and the formation of a furan ring.A plausible biosynthetic pathway for 1 and 2 was proposed.Biological evaluation of the enantiomers of 1 and 2 revealed that(−)-1 and(+)-2 could inhibit the production of TNF-αand IL-6 and the expression of iNOS,COX-2,and p-NF-κB.

关键词： ring bases structurally

Phase/size dual controlled 2D semiconductor In_(2)X_(3)(X=S,Se,Te)for saturable absorption modulation

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Nano Research 2022年第6期15卷 5633-5639页

作者： Weibiao wang Zhexue chen Xinyu Sui Yueqi Li Xinfeng Liu yong Zhang CAS Key Laboratory of Nanosystem and Hierarchical Fabrication CAS Center for Excellence in NanoscienceNational Center for Nanoscience and TechnologyBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China CAS Key Laboratory of Standardization and Measurement for Nanotechnology CAS Center for Excellence in NanoscienceNational Center for Nanoscience and TechnologyBeijing 100190China

The production of two-dimensional nanosheets(2D NSs)with all sizes(1-100 nm)and few(<10)layers is highly desired but far from satisfactory.Herein,we report an all-physical top-down method to produce indium chalcogenide(In2X3(X=S,Se,Te))NSs with wide-range(150-3.0 nm)controlled sizes.The method combines silica-assisted ball-milling and sonication-assisted solvent exfoliation to fabricate multiscale NSs with varying distributions,which are then precisely separated by cascade centrifugation.Multiple characterization techniques reveal that the as-produced In2X3 NSs are intrinsic and defect-free and remainβ-phase during the whole process.The redispersions of In2X3 NSs exhibit prominent excitation wavelength-,solvent-,concentration-,and size-dependent photoluminescence.The NSs-poly(methyl methacrylate)(PMMA)hybrid thin films demonstrate strong size effects in nonlinear saturation absorption.The absolute modulation depths of 35.4%,43.3%,47.2%and saturation intensities of 1.63,1.05,0.83 MW·cm^(−2)(i.e.,163,105,and 83 nJ·cm^(−2))are derived for the In_(2)S_(3),In_(2)Se_(3),and In2Te3 quantum sheets,respectively.Our method paves the way for mass production and full exploration of full-scale 2D NSs.

关键词： semiconductor quantum sheets intrinsic photoluminescence nonlinear saturation absorption

Density Calculation for NaCl-H_2O Solutions in the Liquid-Solid TwoPhase Field in NaCI-H_2O Three-Phase Inclusions

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Acta Geologica Sinica(English Edition) 2015年第3期89卷 911-917页

作者： chen Wenming wang yong chen Weishi Institute of Mineral Resources Chinese Academy of Geological Sciences

Three-phase NaCl-H_2O fluid inclusions featuring halite dissolution temperature（Tm）higher than vapor bubble disappearance temperature（T_h） are commonly observed in porphyry copper/molybdenum deposits,skarn-type deposits and other magmatic- hydrothermal ore deposits.Based on ｜ΔV_1｜（the absolute value of volume variation of NaCl-H_2O solution in a heating or cooling process of inclusions）= ｜ΔV_s｜（the absolute value of volume variation of the halite crystal in a heating or cooling process of inclusions） and on the principle of conservation of the mass of NaCl and H_2O,we systematically calculated the densities of NaCl-H_2O solutions in the solid-liquid two-phase field for temperatures（T_h） from 0.1℃ to 800℃ and salinities from 26.3 wt%to 99.2wt%.Consequently for the first time we obtained the upper limit of the density of NaCI-H_2O solutions in the solid-liquid twophase field for T_b〈T_m inclusions with variant salinities.The results indicate that for inclusions of the T_h〈T_m type with the same T_h,the higher the T_m or salinity is,the higher the density of the NaClsaturated solution will be.If a group of fluid inclusions were homogeneously trapped,they must have the same T_h value and the same T_m or salinity value.This may be used to distinguish homogeneous,inhomogeneous,and multiple entrapments of fluid inclusions.

关键词： Density calculation NaCl-H2O three-phase inclusions Th〈Tm homogeneous trapping,solid-liquid two-phase field

Replanting of broadleaved trees alters internal nutrient cycles of native and exotic pines in subtropical plantations of China

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Forest Ecosystems 2022年第5期9卷 701-709页

作者： yong Lin chengkang Xia Gaoyang Wu Fangchao wang Shengnan wang Yuanqiu Liu Fusheng chen Key Laboratory of National Forestry and Grassland Administration on Forest Ecosystem Protection and Restoration of Poyang Lake Watershed Jiangxi Agricultural UniversityNanchang330045China Jiangxi Forestry Resources Monitoring Center Nanchang330045China Postdoctoral Research Station of Management Science and Engineering Nanchang UniversityNanchang330031China Jiangxi Provincial Key Laboratory of Silviculture College of ForestryJiangxi Agricultural UniversityNanchang330045China

Background:The replanting of broadleaved trees in pure coniferous plantations is widely implemented,as mixed plantations are generally more stable and functional.However,the effect of interspecific interactions between broadleaved and coniferous trees on internal nutrient cycles of conifers remains unclear.Methods:We selected pure coniferous plantations of a native(Pinus massoniana)and an exotic(P.elliottii)pine species and their corresponding mixed plantations with broadleaved trees(Schima superba)in subtropical China,and measured the nitrogen(N)and phosphorus(P)contents in the rhizosphere soils,fine roots,twigs,needles and needle litter of pines.We calculated the root capture,needle resorption and translocation of N and P by pines to determine the mobility of nutrients in trees.Results:Although the N and P in the rhizosphere soils increased due to the replanting of broadleaved trees,the N and P contents in the aboveground tissues of the two pine species did not increase in mixed plantations.Mixed planting had a negative effect on the N and P capture of native pine and a positive effect on that of exotic pine.The N and P resorption efficiencies increased in native pine but were unchanged in exotic pine after the replanting of S.superba.Native pine preferentially employed an aboveground nutrient resorption strategy,whereas exotic pine tended to adopt a belowground nutrient capture strategy after replanting.Translocation of N and P in trees was detected,which reflected the trade-offs between root nutrient capture and needle nutrient resorption.Conclusions:The effect of mixed planting varied between the species of native and exotic pines,and the internal nutrient cycles of both pine species might be dominated by interspecific interaction effects on nutrients rather than soil nutrients.Our study highlights the importance of selecting suitable broadleaved species for replanting in coniferous plantations.

关键词： Interspecific interaction Mixture effect Needle resorption N and P translocation Root capture

Nanocellulose/nitrogen and fluorine co-doped graphene composite hydrogels for high-performance supercapacitors

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Nano Research 2023年第7期16卷 9519-9529页

作者： yong Zhang Qingyun Zhou Wenhui Ma Chaohui wang Xuefeng wang Jiajun chen Tiantian Yu Shan Fan College of Materials Science and Engineering Graphene Functional Materials Research LaboratoryQiqihar UniversityQiqihar 161006China College of Materials Science and Engineering Heilongjiang Province Key Laboratory of Polymeric Composition MaterialQiqihar UniversityQiqihar 161006China School of Chemistry and Chemical Engineering Qiqihar UniversityQiqihar 161006China Department of Practice Teaching and Equipment Management Qiqihar UniversityQiqihar 161006China

Three-dimensional graphene materials have been studied as typical supercapacitors electrode materials by virtue of their ultrahigh specific surface area and good ion transport capacity.However,improvement of the poor volumetric electrochemical performance of these graphene materials has been required although they have high gravimetric energy density.In this work,nanocellulose/nitrogen and fluorine co-doped graphene composite hydrogels(NC-NFGHs)were prepared through a convenient hydrothermal approach utilizing ammonium fluoride as the heteroatom source.Nanocellulose(NC)and high concentration of graphene oxide(GO)were utilized to adjust the structure of NC-NFGHs and increase their packing density.Subsequently,the aqueous symmetric supercapacitor based on NC-NFGH-80 exhibits remarkable gravimetric(286.6 F·g^(-1))and volumetric(421.3 F·cm^(-3))specific capacitance at 0.3 A·g^(-1),good rate performance,and remarkable cycle stability up to 10,000 cycles.Besides,the all-solid-state flexible symmetric supercapacitors(ASSC)fabricated by NC-NFGH-80 also delivered a large specific capacitance of 117.1 F·g^(-1)at 0.3 A·g^(-1)and long service life over 10,000 cycles at 10 A·g^(-1).This compact porous structure and heteroatom co-doped graphene material supply a favorable strategy for high-performance supercapacitors.

关键词： compact graphene composite hydrogel high packing density N/F co-doping gravimetric/volumetric performances supercapacitors