检索结果-南通市图书馆

Pressure-induced hydride superconductors above 200 K

在线全文

学校读者我要写书评

暂无评论

Matter and Radiation at Extremes 2021年第6期6卷 58-66页

作者： Xiaohua Zhang Yaping Zhao Fei Li Guochun Yang State key laboratory of Metastable materials Science and Technology and key laboratory for Microstructural material Physics of Hebei Province School of ScienceYanshan UniversityQinhuangdao 066004China Centre for Advanced Optoelectronic Functional materials Research and key laboratory for UV Light-Emitting materials and Technology of Ministry of Education Northeast Normal UniversityChangchun 130024China

Although it was proposedmany years ago that compressed hydrogen should be a high-temperature superconductor,the goal of room-temperature superconductivity has so far remained out of ***,the successful synthesis of the theoretically predicted hydrides H3S and LaH10 with high superconducting transition temperatures TC provides clear guidance for achieving this *** existence of these superconducting hydrides also confirms the utility of theoretical predictions in finding high-TC *** date,numerous hydrideshave been studied theoretically or experimentally,especially binary ***,some of them exhibit superconductivity above 200 *** gain insight into these high-TC hydrides(>200 K)and facilitate further research,we summarize their crystal structures,bonding features,and electronic properties,as well as their *** on hydrogen structuralmotifs,covalentH3Swith isolated hydrogen and several clathrate superhydrides(LaH10,YH9,and CaH6)are *** predicted hydrides with various H-cages and two-dimensional H motifs are also ***,we present a systematic discussion of the common features,current problems,and future challenges of these high-TC hydrides.

关键词： hydride superconductor bonding

Distribution pattern of acoustic and streaming field during multi-source ultrasonic melt treatment process

在线全文

学校读者我要写书评

暂无评论

China Foundry 2023年第5期20卷 452-460页

作者： Xiao-gang Fang Qi Wei Tian-yang Zhang Ji-guang Liu You-wen Yang Shu-lin Lü Shu-sen Wu Yi-qing Chen School of materials Science and Engineering Hefei University of TechnologyHefei 230009China Engineering Research Center of High-Performance Copper Alloy materials and Processing Ministry of EducationHefei 230009China State key laboratory of material Processing and Die&Mould Technology Huazhong University of Science and TechnologyWuhan 430074China

The ultrasonic melt treatment(UMT)is widely used in the fields of casting and ***,there are certain drawbacks associated with the conventional process of single-source ultrasonic(SSU)treatment,such as the fast attenuation of energy and limited range of *** this study,the propagation models of SSU and four-source ultrasonic(FSU)in Al melt were respectively established,and the distribution patterns of acoustic and streaming field during the ultrasonic treatment process were investigated by numerical simulation and physical *** simulated results show that the effective cavitation zone is mainly located in a small spherical region surrounding the end of ultrasonic horn during the SSU treatment *** the FSU is applied,the effective cavitation zone is obviously expanded in the *** increases at first and then decreases with increasing the vibration-source spacing(Lv)from 30 mm to 100 ***,when the Lv is 80 mm,the area of effective cavitation zone reaches the largest,indicating the best effect of ***,the acoustic streaming level and flow pattern in the melt also change with the increase of *** the Lv is 80 mm,both the average flow rate and maximum flow rate of the melt reach the highest,and the flow structure is more stable and uniform,with the typical morphological characteristics of angular vortex,thus significantly expanding the range of acoustic *** accuracy of the simulation results was verified by physical experiments of glycerol aqueous solution and tracer particles.

关键词： four-source ultrasound acoustic cavitation streaming field vibration-source spacing

Highly flexible ceramic nanofibrous membranes for superior thermal insulation and fire retardancy

在线全文

学校读者我要写书评

暂无评论

Nano Research 2022年第3期15卷 2592-2598页

作者： Xue Mao Li Zhao Kun Zhang Yao-Yu Wang Bin Ding School of Textile Science and Engineering Key Laboratory of Functional Textile Material and Product(Ministry of Education)Xi’an Polytechnic UniversityXi’an 710048China College of Chemistry&materials Science Northwest UniversityXi'an 710127China Innovation Center for Textile Science and Technology College of TextilesDonghua UniversityShanghai 201602China

Ceramic membranes are attractive for thermal management applications due to its lightweight and ultralow thermal conductivity,while it is indispensable to address the long-standing obstacle of its poor mechanical stability and degradation under thermal *** this work,a series of the organic polymer template-modulated yttria doped zirconia(YDZ)nanofibrous membranes with lightweight,superior mechanical and thermal stability are developed through a cost-effective,scalable sol-gel electrospinning and subsequent calcination *** YDZ membranes demonstrate excellent flexibility and foldability,which can be attributed to the tetragonal phase and small crystallite size of the YDZ fibers due to the presence of ***,the fibrous size,grain size,mechanical and thermal stability of YDZ nanofibrous membranes could be tailored by varying the species and molecular weight of polymer *** remarkable performances are obtained through the poly(vinyl pyrrolidone)(PVP)template YDZ nanofibrous membranes,featuring the superior tensile strength up to~4.82 MPa,excellent flexibility with bending rigidity~26 mN,robust thermal stability up to 1,200℃,ultra-low thermal conductivity of 0.008–0.023 W·m^(−1)·K^(−1)(25–1,000℃),and excellent flame retardancy with tolerance of flame up to 1,000℃.The remarkable properties can be attributed to the smaller fibrous size,and higher grain size resulting from PVP *** robust material system is ideal for thermal superinsulation with a wide range of uses from energy saving building applications to spacecraft.

关键词： ceramic nanofibrous membranes flexibility robust mechanical stability ultralow thermal conductivity high-temperature thermal insulation

Epitaxial growth and oxidation behavior of an overlay coating on a Ni-base single-crystal superalloy by laser cladding

维普期刊数据库评论

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 materials Science & Technology 2019年第2期35卷 344-350页

作者： Jingjing Liang Yongsheng Liu Jinguo Li Yizhou Zhou Xiaofeng Sun Institute of Metal Research Chinese Academy of Sciences State key laboratory of Solidification Processing Northwestern Polytechnical University Space Manufacturing Technology (CAS key Lab)

An overlay coating material was deposited on a single crystal superalloy SRR99 by laser *** microstructure and oxidation behavior of this coating was investigated through scanning electron microscopy(SEM) and X-ray diffraction(XRD). The results indicated that although the composition of the coating was chosen based on the γ' composition in René N5 superalloy, the primary solidification phase of this coating during laser cladding was γ-Ni. Furthermore, under the laser cladding condition, fine parallel dendrites grew epitaxially in the coating from the substrate, indicating the single crystal structure of the substrate was reproduced. When the single crystal MCrAlY coating was oxidized at 1000?, both Al_2O_3 and Al_2O_3 formed during initial oxidation process. As the oxidation time proceeded, the presence of Al_2O_3 facilitated the formation of NiAl_2O_4 spinel oxide. Once the spinel was observed, it flourished and induced some porosity in the scale. When the scale thickness increased to 6–7 μm, large area spallation of the scale began.

关键词： Laser cladding Single crystal growth Epitaxy Overlay coating

Microstructure and mechanical properties of Al-10Si alloy modified with Al-5Ti

在线全文

学校读者我要写书评

暂无评论

China Foundry 2018年第6期15卷 405-410页

作者： Ya-ling Liu Chang-jun Wu Hao Tu Xiao-wang Lu Jian-hua Wang Xu-ping Su Jiangsu key laboratory of material Surface Science and Technology School of Materials Science and Engineering Changzhou University National Experimental Teaching Demonstration Center of materials Science and Engineering Changzhou University Jiangsu Collaborative Innovation Center of Photovoltaic Science and Engineering Changzhou University

The microstructure, fracture morphology and mechanical properties of Al-10 Si alloy modified with Al-5 Ti were analyzed and tested by optical microscopy, scanning electron microscopy, and universal electronic testing machine. Compared with unmodified Al-10 Si alloy, the area fraction of α-Al phase in Al-10 Si alloy modified at 740 °C increased first and then decreased with the increase of added amounts of Al-5 Ti, and reached the maximum when the added amount of Al-5 Ti was 0.5 wt.%. When the modification temperature increased from 700 to 740 °C with Al-5 Ti being fixed at 0.5 wt.%, α-Al dendrites were refined obviously and the area fraction remarkably increased. Compared with unmodified Al-10 Si alloy, the ultimate tensile strength and elongation of the alloy modified at 740 °C with 0.5 wt.% Al-5 Ti increased by 9% and 49%, respectively. The fracture surface of modified alloy predominantly exhibited ductile fracture.

关键词： Al-10Si modification microstructure mechanical properties

Synthesis and thermal polymerization of perylene bisimide containing benzocyclobutene groups

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2014年第10期25卷 1367-1370页

作者： Zhi-Jun Wei Ye-Wei Xu Lin Zhang Mei-Ming Luo key laboratory of Green Chemistry and Technology of Ministry of Education College of ChemistrySichuan University Research Center of Laser Fusion China Academy of Engineering Physics Engineering Research Center of Biomass materials Ministry of EducationSchool of Material Science and EngineeringSouthwest University of Science and Technology

Fourfold benzocyclobutene-functionalized perylene bisimide（PBI 4） has been synthesized and its structure was characterized by FTIR,MS and *** 4 can react either with itself,or the appropriate dienophiles to form the corresponding products under appropriate *** polymer film obtained from the reaction of PBI 4 with methyl vinyl silicone rubber possessed excellent film forming properties including *** optical properties of PBI 4 and polymer film obtained from the reaction of PBI 4 and methyl vinyl silicone rubber have been determined by UV/vis and fluorescence spectroscopy.

关键词： Perylene bisimide Benzocyclobutene Thermopolymerization Optical properties

Hierarchical CuO-ZnO/SiO_(2) Fibrous Membranes for Efficient Removal of Congo Red and 4‑Nitrophenol from Water

在线全文

学校读者我要写书评

暂无评论

Advanced Fiber materials 2022年第5期4卷 1069-1080页

作者： Caihong Wang Ke Liu Dong Wang Guomin Wang Paul KChu Zheyi Meng Xuefen Wang State key laboratory for Modification of Chemical Fibers and Polymer materials College of Material Science and EngineeringDonghua UniversityShanghai 201620China key laboratory of Textile Fiber and Products Ministry of EducationHubei International Scientific and Technological Cooperation Base of Intelligent Textile Materials and ApplicationWuhan Textile UniversityWuhan 430200China Department of Physics Department of Materials Science and Engineeringand Department of Biomedical EngineeringCity University of Hong KongHong Kong 999077China

Hierarchical CuO-ZnO/SiO_(2)(CZS)nanofibrous membranes are designed and fabricated to remove Congo red and 4-nitro-phenol two common small molecular pollutants in *** electrospun SiO_(2) fibrous membrane is serves as the substrate for hydrothermal depositing CuO-ZnO *** CZS nanofibrous membrane shows good adsorption characteristics for Congo red due to the hierarchical morphology and the adsorption kinetics where isotherm follows the pseudo-second-order model and Langmuir model,*** maximum adsorption capacity for Congo red is 141.8 mg/***,the membrane exhibits excellent catalytic reduction activity for 4-nitrophenol under mild conditions and over 96%of the pollut-ants are degraded within 90 *** CZS nanofibrous membrane has promising prospects in applications in water treatment and environmental protection because of the good flexibility,easy fabrication,excellent adsorption,and catalytic activity.

关键词： Hierarchical nanofibrous membranes Hydrothermal deposition Electrospun inorganic membranes Pollutant adsorption Catalytic degradation

Electron-impact single ionizaiton for W^(4+) and W^(5+)

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Physics B 2018年第5期27卷 172-178页

作者： Denghong Zhang Luyou Xie Jun Jiang Zhongwen Wu Chenzhong Dong Yinglong Shi Yizhi Qu key laboratory of Atomic and Molecular Physics ＆ Functional materials of Gansu Province College of Physics and Electronic Engineering Northwest Normal University Lanzhou 730070 China Department of physics Tianshui Normal University Tianshui 741000 China College of material Sciences and Opto-electronic Technology University of Chinese Academy of Sciences Beijing 100049 China

Electron-impact single ionization cross sections for W^q＋（q = 4–5） were calculated using the flexible atomic code（FAC） in the level-to-level distorted-wave method, considering the explicit branching ratio. The calculated cross sections are compared with the available theoretical and experiment results in detail. In the case of the contribution from the same channles as the available theoretical results, all of the calculated ionization cross sections agree with the experimental measured cross sections. But the present calculated results are larger than the experimental measurement when all channels contributions are included. Some important channels excitation autoionization（EA） contributions, such as the excitation to higher higher nl subshell from 4 f and 5[s,p], were not included into the available theoretical calculation. In general, the distorted-wave（DW） results are overestimated.

关键词： tungsten ions electron-impact ionization cross section

Improved mechanical properties and strengthening mechanism with the altered precipitate orientation in magnesium alloys

在线全文

学校读者我要写书评

暂无评论

Journal of Magnesium and Alloys 2022年第5期10卷 1256-1267页

作者： Y.J.Wan Y.Zeng Y.C.Dou D.C.Hu X.Y.Qian Q.Zeng K.X.Sun G.F.Quan key laboratory of Advanced Technologies of materials Ministry of EducationSchool of Material Science and EngineeringSouthwest Jiaotong UniversityChengdu 610031China College of materials Science and Engineering Sichuan University of Science and EngineeringZigong 643000China Department of materials The University of ManchesterOxford RoadManchester M139PLUnited Kingdom

Aging prior to twinning deformation was proposed to alter the precipitate orientation of the plate-shapedβ-MgAlfrom(0002)basal planes(named basal plates)to■prismatic planes(named prismatic plates)in AZ31 Mg *** experimental results showed that the compressive yield strength(CYS)of the sample containing prismatic plates increased 40 MPa and the compression ratio raised by 22%compared to that containing basal *** underlying strengthening mechanism was analyzed via a yield strengthen(YS)model with a function of grain size,precipitate characters(size,oritention,fraction)and Schmid factor(SF).It revealed that the improvement of CYS was mainly attributed to the altered precipitate orientation and refined grain size produced by twinning ***,the prismatic plates always have a stronger hardening effect on basal slip than basal plates under the same varites of precipitate diameter and ***,the decreased CRSS ratio of prismatic slip to basal slip revealed that the activity of non-basal slip in Mg alloy might be *** activated slip systems provided more mobile dislocations,contributing to the large compression ratio of the Mg rolled sheet with prismatic plates.

关键词： Precipitate orientation Precipitation strengthening Grain boundary strengthening Yield strength model