检索结果-南通市图书馆

Simultaneously improved the strength and ductility of laser powder bed fused Al-Cr-Fe-Ni-V high-entropy alloy by hot isostatic pressing:Microcrack closure and precipitation strengthening

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 2024年第13期180卷 55-68页

作者： Ziwei Liu zhen Tan Dingyong he zheng Zhou Xingye Guo Wei Shao Haihua Yao Yunfei xue Li Cui Faculty of Materials and Manufacturing Beijing University of TechnologyBeijing 100124China Beijing Engineering Research Center of Eco-materials and LCA Beijing 100124China School of Materials Science and Engineering Beijing Institute of TechnologyBeijing 100081China

Hot isostatic pressing(HIP)is usually applied to reduce the defects including cracks and pores in the materials prepared by laser powder bed fusion(LPBF).In the present research,in order to improve the relative density and mechanical property,HIP was employed on the LPBF-processed Al-Cr-Fe-Ni-V high-entropy alloy(heA)with microcracks and *** microstructure evolution and property improvement induced by HIP were *** the LPBF-processed heA,the microcracks were caused by residual stress and element segregation,and these microcracks as well as the pores reduced significantly after HIP ***,HIP temperature has a more critical effect on the microcrack closure than the holding time,thus,microcracks and pores still existed after HIP-1 treatment(1273 K,8 h),while HIP-2 treatment(1473 K,4 h)could close the microcracks *** crack closure was attributed to the interfacial diffusion of the alloying element under high temperature accompanied by high pressure,and the degree of element diffusion at both interfaces of the cracks determined the bonding strength after crack *** temperatures at high pressure induced more adequate element diffusion and higher bonding *** above high temperature and high pressure also induced the growth of the L1_(2) phase and the precipitation of the B2 phase in ***,the tensile strength and elonga-tion of the LPBF-processed heA after HIP-2 treatment were simultaneously enhanced(80.7%and 222.5%higher than that of LPBF-processed heA,respectively).This could be attributed to the combined effect of microcrack/pore closure and precipitation *** strengthening effect of the B2 phase and L1_(2) phase accounted for 53%(dislocation by-pass mechanism)and 47%(dislocation shearing mechanism)of the total precipitation strengthening,respectively.

关键词： High-entropy alloy Laser powder bed fusion Hot isostatic pressing Crack closure Precipitation strengthening

Quantum anomalous Hall heterostructures

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

National Science Review 2019年第2期6卷 202-204页

作者： Ke he Qi-Kun xue State Key Laboratory of Low Dimensional Quantum Physics Department of Physics Tsinghua University Beijing Academy of Quantum Information Sciences

The discoveries of the integer and fractional quantum Hall effects in the early 1980s unveiled an exotic world of topological quantum matter [1]. This fascinating world, however, remains largely Platonic in the sense that most of the predicted topological quantum phases are still far away from experimental realization. For a time, almost the only way to find a new topological quantum phase was to search for

关键词： Quantum anomalous Hall heterostructures FMI TME

Nutrient exchange and release experiment and its simulation study in lake water-sediment interface

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2006年第3期18卷 591-595页

作者： xue Lian-qing HAO zhen-chun State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering College of Water Resources and Environment Hohai UniversityNanjing 210098 China

The sediment distributed and insolated under lake was collected for experiments. The nutrient layer distribution conditions of sampled sediment and its physical and chemical characteristics were analyzed to simulate and assess the influence degree to lake water quality. Based on the dynamic water exchanging experiments the nutrient release process in sediment and influence mechanism to substance exchanging on water-sediment interface was studied, and the correlation between the changing content of total phosphors and total nitrogen in sediment and covered water were analyzed for setting up a simulation model. At the same time the influence degree is explained in detail. The experimental results indicated that even if clean water without nutrient contents was used for water exchangement so as to decrease pollution or prevent eutrophication, however owing to the vertical nutrient distribution in lake sediment, it will lead to the increasing release amount greatly especially when the organic nutrient contained in sediment turns into inorganic status because of isolation. Besides the release process of total phosphate （TP） and total nitrogen （TN） were modeled and each nutrient＇s exchanging equation at interface caused by covered water nutrient concentration changing was set up. According to the simulating prediction, TP and TN content of cover water will also sustain a steady higher level in a long period. The nutrient release amount of sediment is not only affected by the covered water concentration but also connects with accumulative time. The experiments provide the fundamental theoretical and practical basis for taking ecological restoration project. And research is helpful to prevent or restore lake eutrophication.

关键词： phosphate and nitrogen release water-sediment interface experiments simulation model

Compound Sophorae Decoction:treating ulcerative colitis by affecting multiple metabolic pathways

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Natural Medicines 2021年第4期19卷 267-283页

作者： HONG Zong-Chao CAI Quan WU he-zhen YANG Yan-Fang FAN heng DUAN xue-Yun Hubei University of Chinese Medicine Wuhan 430065China Hubei Provincial Hospital of Traditional Chinese Medicine Wuhan 430061China Hubei Province Academy of Traditional Chinese Medicine Wuhan 430074China Department of Integrated Traditional Chinese and Western Medicine Union HospitalTongji Medical CollegeHuazhong University of Science and TechnologyWuhan 430022China Huangshi No.5 Hospital Huangshi 435005China

Ulcerative colitis(UC)is a chronic refractory non-specific intestinal inflammatory disease that is difficult to be *** discovery of new ulcerative colitis-related metabolite biomarkers may help further understand UC and facilitate early *** may also provide a basis for explaining the mechanism of drug action in the treatment of *** Sophorae Decoction(CSD)is an empirical formula used in the clinical treatment of *** it is known to be efficacious,its mechanism of action in the treatment of UC is *** purpose of this study was to investigate the changes in endogenous substances in UC rats and the effects of CSD on metabolic pathways using the metabonomics *** studies in rats with UC and normal rats were performed using LC-MS/*** with UC induced using TNBS enema were used as the study *** profiling and pathway analysis of biomarkers was performed using statistical and pathway enrichment analyses.36 screened potential biomarkers were found to be significantly different between the UC and the normal groups;it was also found that CSD could modulate the levels of these potential *** was found to be efficacious in UC by regulating multiple metabolic pathways.

关键词： Compound Sophorae Decoction Ulcerative colitis LC-MS/MS Biomarker Metabolomics

Ultrastrong room-temperature phosphorescence in cucurbit[8]uril-mediated crystalline supramolecules for ratiometric detection of phenethylamine

在线全文

学校读者我要写书评

暂无评论

Science China Chemistry 2025年

作者： Qingyu Niu Yingxiang Ye Lingna Su Xu he Zhiqiang Li Yu Liu School of Chemical Engineering and Technology Hebei University of Technology Fujian Provincial Key Laboratory of Polymer Materials College of Chemistry and Materials Science Fujian Normal University Key Laboratory of Advanced Energy Materials Chemistry (Ministry of Education) Nankai University College of Chemistry State Key Laboratory of Elemento-Organic Chemistry Nankai University

It is a great challenge to modulate purely organic fluorescence-phosphorescence dual emission in aqueous solution because the excited singlet and triplet states are in competition with each other. herein, we report a crystalline 1:2 host-guest formed by selfassembly of 4-(4-bromophenyl)-pyridinium derivatives and cucurbit[8]uril, in which a rigid environment rich in weak interactions is directly demonstrated. Due to the inhibition of non-radiative transition and stabilization of triplet exciton in the crystalline environment, the crystalline inclusion complex exhibits ultralong room-temperature phosphorescence lifetime of 3.21 ms with an room-temperature phosphorescence(RTP) quantum yield up to 16.29%. Interestingly, the crystalline 1:2 hostguest complex demonstrates the ability of rapid identification and sensitive fluorescence-phosphorescence ratiometric detection behavior toward phenethylamine, a drug analogue, with a limit of detection as low as 27.5 nM. We believe that this study will undoubtedly broaden the utilizing scopes of RTP and offer a novel avenue for psychoactive substances monitoring.

关键词：

EVchain: An Anonymous Blockchain-Based System for Charging–Connected Electric Vehicles

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Tsinghua Science and Technology 2021年第6期26卷 845-856页

作者： Shiyuan Xu xue Chen Yunhua he North China University of Technology Beijing 100144China Beijing Key Laboratory of Internet of Things Security Institute of Information EngineeringChinese Academy of Sciences(CAS)Beijing 100093China

Purchases of electric vehicles have been increasing in recent years. These vehicles differ from traditional fossil-fuel-based vehicles especially in the time consumed to keep them running. Electric-Vehicle-charging Service Providers(EVSPs) must arrange reasonable charging times for users in advance. Most EVSP services are based on third-party platforms, but reliance on third-party platforms creates a lack of security, leaving users vulnerable to attacks and user-privacy leakages. In this paper, we propose an anonymous blockchain-based system for charging-connected electric vehicles that eliminates third-party platforms through blockchain technology and the establishment of a multi-party security system between electric vehicles and EVSPs. In our proposed system, digital certificates are obtained by completing distributed Public Key Infrastructure(distributed-PKI) identity registration,with the user registration kept separate from the verification process, which eliminates dependence on the EVSP for information security. In the verification process, we adopt smart contracts to solve problems associated with centralized verification and opaque services. Furthermore, we utilize zero-knowledge proof and ring-signature superposition to realize completely anonymous verification, which ensures undeniability and unforgeability with no detriment to anonymity. The evaluation results show that the user anonymity, information authenticity, and system security of our system fulfill the necessary requirements.

关键词： blockchain Electric Vehicles(EV) zero knowledge proof distributed Public Key Infrastructure(distributed-PKI) ring signature smart contract

Preparation, characterization and antibacterial properties of cobalt doped titania nanomaterials

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemical Engineering 2020年第5期28卷 1474-1482页

作者： Dai Shi he Yang Xiangxin xue Institute of Resources and Environment School of MetallurgyNortheastern UniversityShenyang 110819China The Faculty of Mechanical Engineering Shenyang Polytechnic CollegeShenyang 110045China

Cobalt-doped titania(Co-TiO2)nanomaterials were synthesized by the sol–gel method at different calcination *** Escherichia coli(a),Staphylococcus aureus(b)and Candida albicans(c)as target strains,the antibacterial activity in visible light of the nanomaterials were ***-TiO2 nanomaterials were characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM),transmission electron microscopy(TEM),UV–Vis diffuse reflectance spectroscopy(DRS),Fourier transform infrared spectrum(FT-IR)and X-ray photoelectron spectroscopy(XPS).The Co ions in the Co-TiO2 nanomaterial exist in the form of CoTiO3 *** antibacterial properties of Co-TiO2 nanomaterials on ***(a),***(b)and ***(c)were investigated with the oscillating flask method and the inhibition zone *** nanomaterials calcined at 600°C exhibit excellent antibacterial *** bacteriostatic rates for ***,*** and *** reached 99.5%,91.3%and 93.4%*** diameters of the antibacterial rings were up to 36 mm,37 mm,30 mm respectively,and the clarity of the ring was *** antibacterial properties of Co-TiO2 nanomaterials were compared with those of traditional silver sol,zinc oxide sol and Zn-doped TiO2 nanomaterials The mechanism of the influences of Co ions doping on the antibacterial activity of TiO2 nanomaterials was also *** doping of Co ions inhibits the particle size of the antibacterial agent and extends the photocatalytic response range,thereby improving the photocatalytic performance of the antibacterial agent.

关键词： Antibactenal activity Co-doped Visible light TiO2 CoTiO3

Poly(ethylene carbonate)-based electrolytes with high concentration Li salt for all-solid-state lithium batteries

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2018年第6期37卷 488-496页

作者： Zi-Jian he Li-zhen Fan Beijing Advanced Innovation Center for Materials Genome Engineering Institute of Advanced Materials and Technology University of Science and Technology Beijing

High-performance solid polymer electrolyte （SPE） has long been desired for the next-generation high energy density and safe rechargeable lithium batteries. A SPE composed of 80 wt% lithium bis（trifluo-romethanesulfonyl）imide （LiTFSI）, 20% poly（ethylene carbonate）（PEC） and a polyamide （PA） fiber membrane backbone was prepared by solution-casting method. This solid electrolyte exhibits quite high ionic conductivity and lithium ion transference number （t＋）, and excellent mechanical strength. The as-prepared solid electrolyte shows good wettability to porous electrodes during cycles, which is beneficial to form ionically conductive phase throughout porous electrodes. All-solid-state LiFePO4lLi cells assembled with the as-prepared solid electrolyte deliver a high initial discharge specific capacity of 125.7 mAh·g^-1 and good cycling stability at 55 ℃ （93.4% retention at 1C after 200 cycles）, and superior cycle performance. Outstanding electrochemical performance can be mainly ascribed to the improved ionic conductivity in the entire porous electrodes due to the good wettability of SPE.

关键词： Solid polymer electrolyte All-solid-state lithium batteries Poly(ethylene carbonate) Wettability Porous electrodes

Parametric Resonance Analyses for Spar Platform in Irregular Waves

在线全文

学校读者我要写书评

暂无评论

China Ocean Engineering 2018年第2期32卷 236-244页

作者： YANG he-zhen XU Pei-ji School of Engineering University of GlasgowGlasgow G128QQUnited Kingdom School of Naval Architecture Ocean and Civil EngineeringShanghai Jiao Tong UniversityShanghai 200240China

The parametric instability of a spar platform in irregular waves is analyzed. Parametric resonance is a phenomenon that may occur when a mechanical system parameter varies over time. When it occurs, a spar platform will have excessive pitch motion and may capsize. Therefore, avoiding parametric resonance is an important design requirement. The traditional methodology includes only a prediction of the Mathieu stability with harmonic excitation in regular waves. However, real sea conditions are irregular, and it has been observed that parametric resonance also occurs in non-harmonic excitations. Thus, it is imperative to predict the parametric resonance of a spar platform in irregular waves. A Hill equation is derived in this work, which can be used to analyze the parametric resonance under multi-frequency excitations. The derived Hill equation for predicting the instability of a spar can include non-harmonic excitation and random phases. The stability charts for multi-frequency excitation in irregular waves are given and compared with that for single frequency excitation in regular waves. Simulations of the pitch dynamic responses are carried out to check the stability. Three-dimensional stability charts with various damping coefficients for irregular waves are also investigated. The results show that the stability property in irregular waves has notable differences compared with that in case of regular waves. In addition, using the Hill equation to obtain the stability chart is an effective method to predict the parametric instability of spar platforms. Moreover, some suggestions for designing spar platforms to avoid parametric resonance are presented, such as increasing the damping coefficient, using an appropriate RAO and increasing the metacentric height.

关键词： spar platform instability parametric resonance Mathieu equation irregular waves dynamic responses