检索结果-南通市图书馆

Journal of Iron and Steel Research(International) 2020年第8期27卷 940-951页

作者： Wei-wei Guo Xiao-xin Zhang Ying-xue Chen Zhi-yuan Hong Qing-zhi Yan Institute of Nuclear Materials School of Materials Science and EngineeringUniversity of Science and Technology BeijingBeijing 100083China Advanced Energy Research Center Shenzhen UniversityShenzhen 518060GuangdongChina Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province College of Optoelectronic EngineeringShenzhen UniversityShenzhen 518060GuangdongChina

Advanced oxide metallurgy technique was adopted to produce 100-kg Y-bearing 12Cr ferritic/martensitic steel via vacuum induction melting and casting route. Subsequently, nine specimens at top, middle and bottom regions of the sheet were char-acterized to evaluate the homogeneity of chemical composition, microstructure and mechanical properties. The small vibra-tion of hardness (200–220 HBW), ultimate tensile strength (672–678 MPa), yield strength (468–480 MPa), total elongation (26.2%–30.5%) and Charpy energy at room temperature (98–133 J) and at ??40 ℃ (12–40 J) demonstrated that mechanical properties’ homogeneity of Y-bearing steel was acceptable although slight Y segregation and inhomogeneous microstructure occurred at the bottom. Furthermore, the effect of Y content on microstructure characteristics and mechanical properties was explained and the comparison of failure mechanism for the dual-phase steel between tensile test (i.e., quasi-static loading) and Charpy test (i.e., dynamic loading) was discussed in detail.

关键词： Y-bearing ferritic/martensitic steel Casting homogeneity Chemical composition Microstructure characteristics Mechanical property

A novel method of utilizing static mixer to obtain mixing homogeneity of multi-species powders in laser metal deposition

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 Journal of Aeronautics 2023年第1期36卷 423-433页

作者： Jipeng CHEN Shouchun XIE He HUANG School of Mechanical and Electronic Engineering Nanjing Forestry UniversityNanjing 210037China Nanjing Huirui Photoelectric Technology Co. LtdNanjing 211121China

Real-time mixing of multi-species powder challenges Laser Metal Deposition(LMD)of Functionally Graded Materials(FGMs).The current work proposes a novel method of using a static mixer to realize rapid,uniform multi-species powder mixing.Firstly,copper powder and 316L stainless steel powder are selected to complete the powder mixing observation experiment with Scanning Electron Microscope(SEM)and Energy Dispersive Spectrometer(EDS).Secondly,computational fluid dynamics and particle mixing simulation models are used to analyze the flow field and particle motion characteristics in the static mixer.Finally,LMD experiment and metallo-graphic observation are carried out with 316L stainless steel powder and WC powder to verify the feasibility of the static mixer.This study provides a theoretical and practical basis for powder mixing in laser processing with a static mixer.The conclusions can also be applied to other processing fields requiring real-time and uniform mixing of multi-species powders.

关键词： homogeneity Laser metal deposition Multi-species powder Mixing Static mixer

Improving ingot homogeneity by modified hot-top pulsed magneto-oscillation

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research(International) 2022年第12期29卷 1939-1950页

作者： Fan Zhang Hong-gang Zhong Yu-qian Yang Ming-xu Pan Ren-xing Li Qi-jie Zhai Center for Advanced Solidification Technology Shanghai UniversityShanghai 200444China Daye Special Steel Co. Ltd.Huangshi 214429HubeiChina

Heavy ingots,especially the ingot of more than 10 t,often contain detrimental heterogeneous defects,such as macrosegregation,shrinkage pipes,and cracks.Hot-top pulsed magneto-oscillation(HPMO)can refine the solidified structure of ingot and improve their homogeneity.However,it may exacerbate the positive segregation at the upper part of the ingot body.Thus,a round table HPMO riser with a feeding part was designed,and the microstructure and macrosegregation of Al–Si alloy ingots solidified with and without HPMO were investigated.The simulation and experimental results indicated that round table HPMO riser could enable fine and uniform solidified structures in the whole ingot body;in the meantime,feeding part allowed the melt with enriched solute to gather in the upper part of the riser until the last solidification stage of ingot.This provides an effective approach for obtaining highly homogenized ingots.

关键词： homogeneity Hot-top pulsed magneto-oscillation Heavy ingot Macrosegregation Simulation

The Contribution of United States Aircraft Reconnaissance Data to the China Meteorological Administration Tropical Cyclone Intensity Data:An Evaluation of homogeneity

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

Advances in Atmospheric Sciences 2024年第4期41卷 639-654页

作者： Ming YING Xiaoqin LU Shanghai Typhoon Institute China Meteorological AdministrationShanghai 200030China

This paper investigates the homogeneity of United States aircraft reconnaissance data and the impact of these data on the homogeneity of the tropical cyclone(TC)best track data for the seasons 1949-1987 generated by the China Meteorological Administration(CMA).The evaluation of the reconnaissance data shows that the minimum central sea level pressure(MCP)data are relatively homogeneous,whereas the maximum sustained wind(MSW)data show both overestimations and spurious abrupt changes.Statistical comparisons suggest that both the reconnaissance MCP and MSW were well incorporated into the CMA TC best track dataset.Although no spurious abrupt changes were evident in the reconnaissance-related best track MCP data,two spurious changepoints were identified in the remainder of the best-track MCP data.Furthermore,the influence of the reconnaissance MSWs seems to extend to the best track MSWs unrelated to reconnaissance,which might reflect the optimistic confidence in making higher estimates due to the overestimated extreme wind“observations”.In addition,the overestimation of either the reconnaissance MSWs or the best track MSWs was greater during the early decades compared to later decades,which reflects the important influence of reconnaissance data on the CMA TC best track dataset.The wind-pressure relationship(WPR)used in the CMA TC best track dataset is also evaluated and is found to overestimate the MSW,which may lead to inhomogeneity within the dataset between the aircraft reconnaissance era and the satellite era.

关键词： tropical cyclone intensity homogeneity best track aircraft reconnaissance

An investigation on improving the homogeneity of plasma generated by linear microwave plasma source with a length of 1550 mm

在线全文

学校读者我要写书评

暂无评论

Plasma Science and Technology 2021年第2期23卷 7-16页

作者：周继承徐伟陈特超 School of Energy Science and Engineering Central South UniversityChangsha 410083People's Republic of China Hunan Red Solar Photoelectricity Science and Technology Co. LtdChangsha 410083People's Republic of China

To develop a larger in-line plasma enhanced chemical vapor deposition(PECVD)device,the length of the linear microwave plasma source needs to be increased to 1550 mm.This paper proposes a solution to the problem of plasma inhomogeneity caused by increasing device length.Based on the COMSOL Multiphysics,a multi-physics field coupling model for in-line PECVD device is developed and validated.The effects of microwave power,chamber pressure,and magnetic flux density on the plasma distribution are investigated,respectively,and their corresponding optimized values are obtained.This paper also presents a new strategy to optimize the wafer position to achieve the balance between deposition rate and film quality.Numerical results have indicated that increasing microwave power and magnetic flux density or decreasing chamber pressure all play positive roles in improving plasma homogeneity,and among them,the microwave power is the most decisive influencing factor.It is found that the plasma homogeneity is optimal under the condition of microwave power at 2000 W,chamber pressure at 15 Pa,and magnetic field strength at 45 mT.The relative deviation is within−3.7%to 3.9%,which fully satisfies the process requirements of the equipment.The best position for the wafer is 88 mm from the copper antenna.The results are very valuable for improving the quality of the in-line PECVD device.

关键词： in-line PECVD linear microwave plasma source multi-physics field COMSOL simulation homogeneity

homogeneity of H_(cj) in Sintered Bulk Nd-Fe-B Magnets

在线全文

学校读者我要写书评

暂无评论

Journal of Rare Earths 2006年第z2期24卷 314-317页

作者：谈萍罗建军李增峰周济 Northwest Institute for Non-Ferrous Metal Research

High performance magnets not only have high magnetic properties, but also have good homogeneity. The homogeneous of Nd14.2DyxAl0.8Cu0.1B6.2Febal. bulk magnets was studied. The sizes of the samples produced by conventional sintering process were 53×50.5×25.3/40.2/50.4/61.0 mm. The magnetic character and microstructure of the samples were determined by NIM-10000H hysteresigraph, optical metaloscope, and SEM respectively. The results show that the Hcj reduces with increasing C content at the same process parameters. And the Hcj shows dependence not only on the ageing processing but also on the size of the bulk and loading capacity etc. The Hcj increases with prolonging ageing time and the ageing time should be different with different size of the bulk. With the increase of the loading capacity, the Hcj reduces promptly and is very inhomogeneous. The microstructure of the samples shows that the grain of the hard magnetic phase is finer and the neodymium-rich boundary is distributed homogeneously with prolonging ageing time. And so is the sample in a small amount of the bulks.

关键词： homogeneity Hcj sintered magnets rare earths

Effect of impeller design on homogeneity, size and strength of pharmaceutical granules produced by high-shear wet granulation

在线全文

学校读者我要写书评

暂无评论

Particuology 2015年第6期13卷 31-39页

作者： Zakaria Mirza Jiangtao Liu Yoann Glocheux Ahmad B. Albadarin Gavin M. Walker Chirangano Mangwandi School of Chemistry and Chemical Engineering Queen's University Belfast Belfast BT9 SAG Northern Ireland UK Synthesis & Solid State Pharmaceuticals Center (SSPC) Department of Chemical and Environmental Science. University of Limerick Ireland

Small mixer impeller design is not tailored for granulation because impellers are intended for a wide range of processes. The aim of this research was to evaluate the performances of several impellers to provide guidance on the selection and design for the purposes of granulation. Lactose granules were produced using wet granulation with water as a binder. A Kenwood KM070 mixer was used as a standard apparatus and five impeller designs with different shapes and surface areas were used. The efficacy of granulate for- mation was measured by adding an optically sensitive tracer to determine variations in active ingredient content across random samples of granules from the same size classes. It was found that impeller design influenced the homogeneity of the granules and therefore can affect final product performance. The vari- ation in active ingredient content across granules of differing size was also investigated. The results show that small granules were more potent than larger granules,

关键词： Granule strength Impeller design homogeneity High-shear granulation Lactose monohydrate

The Evolution of Hardness homogeneity in Commercially Pure Ti Processed by ECAP

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 Wuhan University of Technology(Materials Science) 2014年第3期29卷 578-584页

作者：刘晓燕 ZHAO Xicheng YANG Xirong JIA Jiangping QI Boli School of Metallurgical Engineering Xi'an University of Architecture and Technology Xi'an Shaangu Power Co. Ltd

The evolution of hardness homogeneity in commercially pure titanium processed by equal channel angular pressing （ECAP） for up to 4 passes following route C at room temperature using a die of 90° was investigated by recording the microhardness on the cross-sectional and longitudinal planes of each billet. The results show that the hardness increases significantly after the first pass although there is a region of lower hardness on the cross-section running in a band near the bottom surface of the billet, and then increases by very small amounts in subsequent passes. With increasing numbers of passes, the lower hardness region near the bottom surface disappears and the microhardness values are distributed homogeneously throughout the cross- sectional and longitudinal planes after 4 passes of ECAP. The microhardness values in the central regions of the billet are slightly lower than those of the top and bottom surfaces. The results show that good homogeneity may be achieved throughout the billets after 4 passes of ECAP following route C.

关键词： commercially pure titanium equal channel angular pressing hardness homogeneity

Relations among homogeneity, collapsibility and nonconfounding in distribution effects

在线全文

学校读者我要写书评

暂无评论

Applied Mathematics(A Journal of Chinese Universities) 2010年第3期25卷 291-296页

作者： WANG Xue-li GAO Li School of Science Beijing University of Posts and Telecommunications Beijing 100876 China Department of Mathematics Binzhou University Shandong 256600 China

In this paper, the concept of distribution effect is proposed without the causal diagram. Following the notation of Stone [11], we assume that the exposure treatment X is an unknown deterministic function of the confounder set Pa（X） and a random error ε. We discuss sufficient and necessary conditions for homogeneity, collapsibility and nonconfounding for distribution effects and discuss relations among them.

关键词： Collapsibility confounding homogeneity distribution effect.

Influence of the Compacts homogeneity on the Incidence of Cracks during Thermal Debinding in Ceramic Injection Molding

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2009年第2期25卷 264-268页

作者： Xianfeng Yang Zhipeng Xie Yong Huang State Key Laboratory of New Ceramics and Fine Processing Department of Materials Science and Engineering Tsinghua University Beijing 100084 China

During thermal debinding in ceramic injection molding, the inhomogeneity of green body is a key origin of cracks. In this study, the impact of low molecular weight binders on the homogeneity of the green body was investigated. Incidence of cracks during thermal debinding indicated that the volume ratio of wax to stearic acid should be out of high viscosity and incompletely wetting region. In these two formulation regions, typical inhomogeneous microstructures were observed. By mercury intrusion method, it was shown that pore size distribution of the debinded compacts was determined by thermal degradation of low molecular weight binders. A particle-rich region model was established to predict the nucleation of cracks caused by solid loading fluctuation. The criterion of cracks nucleation was that local capillary force from solid loading fluctuation was larger than the suction force from the surroundings. © 2009 by The Editorial Board of Journal of Materials Science and Technology.

关键词： Ceramic injection molding Cracks Debinding homogeneity