检索结果-南通市图书馆

PRECIPITATION BEHAVIOR Of M_(2)N IN A HIGH-NITROGEN AUSTENITIC STAINLESS STEEL DURING ISOTHERMAL AGING

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 2007年第2期20卷 95-101页

作者： f. Shi L.J. wang W.f. Cui C.M. Liu School of Materials ＆ Metallurgy Northeastern UniversityShenyang 110004 China

The precipitation behavior of M2N and the microstructural evolution in a Cr-Mn austenitic stainless steel with a high nitrogen content of 0.43mass% during isothermal aging has been investigated using optical microscopy （ OM）, scanning electron microscopy （SEM）, and transmission electron microscopy （TEM）. The aging treatments have led to the decomposition of nitrogen supersaturated austenitic matrix through discontinuous cellular precipitation. The precipitated cells comprise alternate lamellae of M2N precipitate and austenitic matrix. This kind of precipitate morphology is similar to that of pearlite. However, owing to the non-eutectoidic mechanism of the reaction, the growth characteristic of the cellular precipitates is different from that of pearlite in fe-C binary alloys. M2N precipitate in the cell possesses a hexagonal crystal structure with the parameters a = 0.4752nm and c = 0.4429nm, and the orientation relationship between the M2V precipitates and austenite determined from the SADP is [01^-10]M2N//[101]γ, [2^-1^-10]M2N//[010]γ.

关键词： austenitic stainless steel high nitrogen microstructureisothermal aging precipitation

Atomistic calculations of surface and interfacial energies of Mg_(17)Al_(12)-Mg system

在线全文

学校读者我要写书评

暂无评论

Journal of Magnesium and Alloys 2018年第4期6卷 375-383页

作者： f.X.wang B.Li Department of Chemical and Materials Engineering University of NevadaRenoNV 89557USA Nevada Institute for Sustainability University of NevadaRenoNV 89557USA

It is well known that precipitation hardening in magnesium(Mg)alloys is far less effective than in aluminum ***,it is important to understand the surface and interfacial structure and energetics between precipitates and *** upscale modeling of magnesium alloys,these energy data are of great *** this work,we calculated the surface and interfacial energies of Mg_(17)Al_(12)-Mg system by carefully selecting the surface or interface termination,using atomistic *** results show that,the higher fraction of Mg atoms on the surface,the lower the surface energy of Mg_(17)Al_(12).The interfacial energy of Mg/Mg_(17)Al_(12)was calculated in which the Burgers orientation relationship(OR)was *** was found that the(011)P|(0002)Mg interface has the lowest interfacial energy(248 mJ/m 2).Because the Burgers OR breaks when{10¯12}twin occurs,which reorients the matrix,the interfacial energy for Mg_(17)Al_(12)and a{10¯12}twin was also *** results show that after twinning,the lowest interfacial energy increases by 244 mJ/m^(2),and the interface becomes highly incoherent due to the change in orientation relationship between Mg_(17)Al_(12)and the matrix.

关键词： Mg_(17)Al_(12) Surface energy Interfacial energy Atomistic simulation

Lightning ablation suppression of aircraft carbon/epoxy composite laminates by metal mesh

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11期35卷 2693-2704页

作者： f.S.wang Y.Zhang X.T.Ma Z.Wei J.f.Gao School of Mechanics Civil Engineering and ArchitectureNorthwestern Polytechnical UniversityXi’an710129China The Research Institute for Special Structures of Aeronautical Composite Ji’nan250023China

Three-dimensional finite element(fE)models of carbon/epoxy composite laminates with copper mesh and aluminum mesh protection were established subjected to lightning strike,in which different mesh spacing was *** of numerical method was verified and impulse current waveforms with different current peaks were applied according to aircraft lightning ***-electrical material parameters varying with temperature were added into numerical *** deletion method was used to deal with lightning ablation elements of composite *** results show that ablation area and depth of composite laminates with metal mesh protection are significantly smaller,which proves good protection effectiveness of metal meshes on anti-lightning *** denser the mesh spacing,the better the anti-lightning strike will *** of composite laminates with copper mesh has better effects than that of aluminum *** the effect of mesh spacing variation on composite structural weight and anti-lightning strike,the ideal mesh spacing was obtained.

关键词： Lightning strike Carbon/epoxy composites Ablation Mesh protection

Voltage-induced penetration effect in liquid metals at room temperature

在线全文

学校读者我要写书评

暂无评论

National Science Review 2020年第2期7卷 366-372页

作者： frank f Yun Zhenwei Yu Yahua He Lei Jiang Zhao wang Haoshuang Gu Xiaolin wang Institute for Superconducting and Electronic Materials Australian Institute for Innovative Materials University of Wollongong Laboratory of Bioinspired Smart Interfacial Science Technical Institute of Physics and Chemistry Chinese Academy of Sciences Hubei Key Laboratory of ferro & Piezoelectric Materials and Devices Faculty of Physics and Electronic Sciences Hubei University ARC Centre of Excellence in future Low-Energy Electronics Technologies University of Wollongong

Room-temperature liquid metal is discovered to be capable of penetrating through macro-and microporous materials by applying a voltage. The liquid metal penetration effects are demonstrated in various porous materials such as tissue paper, thick and fine sponges, fabrics, and meshes. The underlying mechanism is that the high surface tension of liquid metal can be significantly reduced to near-zero due to the voltage-induced oxidation of the liquid metal surface in a solution. It is the extremely low surface tension and gravity that cause the liquid metal to superwet the solid surface, leading to the penetration phenomena. These findings offer new opportunities for novel microfluidic applications and could promote further discovery of more exotic fluid states of liquid metals.

关键词： penetration effects liquid metals surface tension porous materials superwet

Bowel preparation before colonoscopy: Consequences, mechanisms, and treatment of intestinal dysbiosis

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

World Journal of Gastroenterology 2025年第2期31卷 13-26页

作者： Ze-Long Zheng Qing-fan Zheng Li-Qiang wang Yi Liu Department of Gastroenterology(Endoscopy Center) China-Japan Union Hospital of Jilin UniversityChangchun 130033Jilin ProvinceChina

The term“gut microbiota”primarily refers to the ecological community of various microorganisms in the gut,which constitutes the largest microbial community in the human *** adequate bowel preparation can improve the results of colonoscopy,it may interfere with the gut *** preparation for colonoscopy can lead to transient changes in the gut microbiota,potentially affecting an individual’s health,especially in vulnerable populations,such as patients with inflammatory bowel ***,measures such as oral pro-biotics may ameliorate these adverse *** focused on the bowel prepa-ration-induced changes in the gut microbiota and host health status,hypothesized the factors influencing these changes,and attempted to identify measures that may reduce dysbiosis,thereby providing more information for individualized bowel preparation for colonoscopy in the future.

关键词： Bowel preparation Colonoscopy Microbiota Inflammatory bowel disease Probiotics

formation and aggregation number of sodium dodecyl sulphonate-polyvinylpyrrolidone aggregates

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 Science Bulletin 1997年第21期42卷 1810-1814页

作者： Li, f Li, GZ Xu, GY wang, HQ Shandong Univ State Educ Comm Key Lab Colloid & Interface Chem Jinan 250100 Peoples R China

THE interaction of surfactants with water-soluble polymers has been an active subject for manyyears. Early investigations were mainly concerned with the effect of synthetic detergents onnatural proteins, such as gel. These studies were motivated by observations of biologicalphenomena involving surfactants and proteins such as the inactivation of bacterial

关键词： aggregation number surface tension fluorescence sodium dodecyl sulphonate polyvinylpyrrolidone.

full-band error control and crack-free surface fabrication techniques for ultra-precision fly cutting of large-aperture KDP crystals

在线全文

学校读者我要写书评

暂无评论

frontiers of Mechanical Engineering 2017年第2期12卷 193-202页

作者： f. H. ZHANG S. f. wang C. H. AN J. wang Q. XU Department of Mechanical Engineering Harbin Institute of TechnologyHarbin 150001 China Chengdu fine Optical Engineering Research Center Chengdu 610041China

Large-aperture potassium dihydrogen phos- phate （KDP） crystals are widely used in the laser path of inertial confinement fusion （ICf） systems. The most common method of manufacturing half-meter KDP crystals is ultra-precision fly cutting. When processing KDP crystals by ultra-precision fly cutting, the dynamic characteristics of the fly cutting machine and fluctuations in the fly cutting environment are translated into surface errors at different spatial frequency bands. These machin- ing errors should be suppressed effectively to guarantee that KDP crystals meet the full-band machining accuracy specified in the evaluation index. In this study, the anisotropic machinability of KDP crystals and the causes of typical surface errors in ultra-precision fly cutting of the material are investigated. The structures of the fly cutting machine and existing processing parameters are optimized to improve the machined surface quality. The findings are theoretically and practically important in the development of high-energy laser systems in China.

关键词： ultra-precision fly cutting large-aperture KDP crystals spatial frequency processing error

Dynamic and ultrastructural study of sphincter of Oddi in early-stage cholelithiasis in rabbits with hypercholesterolemia

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

World Journal of Gastroenterology 2000年第1期6卷 102-106页

作者： Wei JG wang YC Du f Yu HJ Department of Radiology Tangdu Hospitalthe Fourth Military Medical UniversityXi'an 710038Shaanxi ProvinceChina

AIM To study the relationship between pre-formation of gallstone and the kinetics and ultra-structure of sphincter of *** Adult female rabbits were used anddivided into 3 groups,and fed with either normalor high cholesterol diet for four or eight *** group contained eight *** of sphincter of Oddi,biliarycineradiography,gallbladder volumemeasurement and ultrastructure observationunder electron microscope were *** In groups Ⅰ and Ⅱ,the basalpressure in low-pressure ampulla or highpressure zone of sphincter of Oddi waselevated,the amplitude of phasic contractionwas decreased and the volume of gallbladderwere increased,with a significant difference(Pfrom those of *** werefound in group Ⅱ rabbits(7/8).Undercineradiography,low-pressure ampulla showeda spasmodic status without apparent *** electron microscope,insidethe muscular cells of sphincter of Oddi,loosening of microfilament and swelling ofplasmosomes which congregated at the top *** amount showed no obviouschange under nitric oxide synthase(NOS)*** Twisting of the microfilamentand disarrangement of kink macula densa insidethe muscular ceils suggested that the sphincterof Oddi was under spasmodic *** diastolic function caused andaggravated the stasis of cystic *** plasmosome could be one of theimportant factors in elevating the tonic pressureof sphincter of Oddi.

关键词： Subject headings hypercholesterolemia cholithiasis sphincter of Oddi/ultrastructure

flowback and early-time production modeling of unconventional gas wells using an improved semi-analytical method

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Petroleum Science 2023年第6期20卷 3441-3449页

作者： Miao Zhang Kien Nguyen Zhi-Qiang wang Luis f.Ayala College of Petroleum Engineering China University of PetroleumBeijing102249China University of Tulsa USA The Pennsylvania State University USA

Multiple fractured horizontal wells (MfHWs) currently are the only possible means of commercial production from the low and ultra-low permeability unconventional gas reservoirs. In early production time, flowback fluid, which constitutes of hydraulic water and gas flow within fractures, is collected and analyzed. flowback analysis has been shown to be a useful tool to estimate key properties of the hydraulic fracture such as conductivity and pore volume. Until date, most tools of flowback analysis rely on empirical and approximate methods. This study presents an improved Green-function-based semi-analytical solution for performance analysis of horizontal gas wells during flowback and early production periods. The proposed solution is derived based on coupling the solutions of two domains: a rigorously derived Green’s function-based integral solution for single-phase gas flow in matrix, and a finite-difference, multiphase solution for gas–water two-phase flow in the fracture. The validity of proposed semi-analytical solution is verified by finely gridded numerical models built in a commercial simulator for a series of synthetic cases considering a variety of fluid and reservoir property combinations, as well as various different production constraints. Comparisons against available empirical and approximate methods are also provided for these cases.

关键词： Hydraulic fractures flowback Unconventional gas wells