检索结果-南通市图书馆

Preparation of nano-sized tungsten carbide via fluidized bed

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 Chemical Engineering 2020年第3期28卷 923-932页

作者： Feng Pan Zhan Du Shaofu li Jun li Meiju Zhang Maoqiao Xiang Qingshan Zhu State Key Laboratory of Multiphase Complex Systems Institute of Process EngineeringChinese Academy of Sciences(CAS)Beijing 100190China Information Research Institute of Emergency Management Department Beijing 100084China University of Chinese Academy of Sciences Beijing 100049.China

Ultrafine or nano-sized of tungsten carbide(wc)is the key material to prepare ultrafine grained cemented *** this paper,nano-sized wc powders were directly prepared by using industrial nano-needle violet tungsten oxide(WO2.72)as the raw material,a fluidized bed as the reactor,and CO as the carbonization *** relationship between particle sizes and reaction temperatures,residence times,atmospheres has been investigated *** addition,the physical–chemical indexes(such as residual oxygen,total carbon and free carbon)of the products were *** results indicated that the particle size of wc increased with the increase of temperature from 800 to 950°*** the residence time increased,the particle size decreased gradually,and then increased due to slight *** introduction of hydrogen reduced the carbonization rate,and is not beneficial to obtaining nano-sized *** that satisfy the standard were obtained when WO2.72 reacted with CO at 850°C,900°C and 950°C for 3.0 h,2.5 h and 2.0 h,*** particle sizes of the three samples calculated from the specific surface area were 46.4 nm,53.2 nm and 52.1 nm,respectively.

关键词： Nanoparticles Violet tungsten oxide Nano tungsten carbide Fluidized-bed Reduction-carbonization Process control

Use of glycated albumin for the identification of diabetes in subjects from northeast China

在线全文

学校读者我要写书评

暂无评论

World Journal of Diabetes 2021年第2期12卷 149-157页

作者： Guo-Yan li Hao-Yu li Qiang li Department of Endocrinology and Metabolism The Second Affiliated Hospital of Harbin Medical UniversityHarbin 150080Heilongjiang ProvinceChina Faculty of Population Health Sciences University College LondonLondon WC1E 6BTUnited Kingdom

BACKGROUND Metabolic memory is important for the diagnosis and treatment of diabetes in the early stage,and in maintaining blood glucose concentrations within the normal *** clinical diagnosis of diabetes mellitus is currently made using fasting plasma glucose,2 h-plasma glucose(2h-PG)during a 75 g oral glucose tolerance test,and hemoglobin A1c(HbA1c)***,the fasting plasma glucose test requires fasting,which is a barrier to screening,and reproducibility of the 2h-PG level is ***1c is affected by a shortened red blood cell *** patients with anemia and hemoglobinopathies,the measured HbA1c levels may be *** with HbA1c,glycated albumin(GA)is characterized by more rapid and greater changes,and can be used to diagnose new-onset diabetes especially if urgent early treatment is required,for example in gestational *** this study,we provided cutoff values for GA and evaluated its utility as a screening and diagnostic tool for diabetes in a large high-risk group *** To evaluate the utility of GA in identifying subjects with diabetes in northeast China,and to assess the diagnostic accuracy of the proposed GA cutoff in the diagnosis of diabetes *** This cross-sectional study included 1935 subjects,with suspected diabetes or in high-risk groups,from 2014 to 2015 in the Second Affiliated Hospital of Harbin Medical University(Harbin,China).The use of GA to identify diabetes was investigated using the area under the receiver operating characteristic curve(AUC).The GA cutoffs were derived from different 2h-PG values with hemoglobin A1c cutoffs used as a calibration *** The GA cutoff for the diagnosis of diabetes mellitus was 15.15%from the receiver operating characteristic(ROC)*** analysis demonstrated that GA was an efficient marker for detecting diabetes,with an AUC of 90.3%.CONCLUSION Our study supports the use of GA as a biomarker for the diagnosis of diabetes.

关键词： Glycated albumin Receiver operating characteristic Cut-off Hemoglobin A1c Diagnosis Diabetes mellitus

Preparation of wc/CoCrFeNiAl0.2 high-entropy-alloy composites by high-gravity combustion synthesis

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

International Journal of Minerals,Metallurgy and Materials 2020年第2期27卷 244-251页

作者： Guan-nan Zhang Xiao Yang Zeng-chao Yang Yong li Gang He Jiang-tao li Key Laboratory of Cryogenics Technical Institute of Physics and ChemistryChinese Academy of SciencesBeijing 100190China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049China

The wc/CoCrFeNiAl0.2 high-entropy alloy(HEA)composites were prepared through high-gravity combustion *** preparation method is presented ***,using a designed suitable multiphase thermite system,the molten CoCrFeNiAl0.2 HEA was fabricated using low-cost metal *** molten HEA was subsequently infiltrated into the wc layer to fabricate wc/CoCrFeNiAl0.2 composites in a highgravity *** porosity of the wc/CoCrFeNiAl0.2 composites was down-regulated,and their compressive yield strength was up-regulated when the high-gravity field was increased from 600g to 1500g because this infiltration process of a HEA melt into the wc layer is driven by centrifugal *** wc particles in the composites exhibited a gradient distribution along the direction of the centrifugal force,which was attributed to the combined action of the high-gravity field and the temperature gradient *** Vickers hardness of the sample was down-regulated from 9.53 to 7.41 GPa along the direction of the centrifugal force.

关键词： composites high-entropy alloy high-gravity combustion synthesis gradient material

Adhesion Wear on Tool Rake and Flank Faces in Dry Cutting of Ti-6Al-4V

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Mechanical Engineering 2011年第6期24卷 1089-1094页

作者： DENG Jianxin li Yousheng ZHANG Hui Department of Mechanical Engineering Shandong UniversityJinan 250061China

Titanium alloys are very chemically reactive and,therefore,have a tendency to weld to the cutting tool during *** deterioration in the tool life caused by adhesion is a serious problem when titanium alloys are cut using carbide *** chemical reactivity of titanium alloys with carbide tool materials and their consequent welding by adhesion onto the cutting tool during dry cutting leads to excessive chipping,premature tool failure,and poor surface *** the present study,dry turning and milling tests were carried out on Ti-6Al-4V alloys with wc?Co carbide *** adhesion on the tool rake and flank face was explored,the adhesive joint interface between the workpiece materials and tools were *** observation showed that adhesion can be observed both on the rake and the flank face,and was more pronounced in rake face than in flank *** was evidence of element diffusion from the tool rake face to the adhering layer(vice versa) through the adhesive joint interface,which leads to the tool element loss and microstructure *** the adhering materials at the flank face can be easily separated from the joint interface owing to the lower temperature and less pressure at the flank face,the adhesive wear attack results in an abrasive wear in the flank ***,adhesion is more notable in turning than in *** proposed research provides references for studying the adhesion between the workpiece materials and the tools,the adhesion mechanisms and their effect on the tool wear.

关键词： adhesion wear dry cutting carbide tools Ti-6Al-4V alloy

Phase Evolution during the Sintering of Submicron Ti(C,N)-Based Cermets

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2001年第4期20卷 248-254页

作者： li, CH Xiong, WH Yu, LX Huazhong Univ Sci & Technol State Key Lab Plast Forming Simulat & Die & Mould Wuhan 430074 Peoples R China

The submicron powder mixtures of TiC-TiN-wc-Mo-C-Ni sintered at 1400degreesC or below in vacuum were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analyses. The results showed that Mo2C formed at 800degreesC or below. Both wc and Mo2C disappeared at 1200degreesC, and TiN disappeared at 1250degreesC. In addition, the variations of lattice constants of the titanium carbonitride and nickel binder phase with sintering temperature were experimentally obtained, and the reason was analyzed.

关键词： submicron cermet phase sintering

Rare Earth Doped New Cemented Carbide with Ni-Co Binder for Mining

在线全文

学校读者我要写书评

暂无评论

Journal of Central South University 2000年第3期12卷 143-145页

作者： ZHANG li CHEN Shu Powder Metallurgy Factory Central South UniversityChangsha 410083China Changsha Research Institute of Mining and Metallurgy Changsha 410012China

A method, doping wc with La(NO 3) 3, of producing cemented carbide with rare earth was introduced. The effects of lanthanum on the mechanical properties and microstructure of wc 9(Co 75%Ni) cemented carbide were studied and a rock drilling experiment was carried *** experimental results show that both transverse rupture strength (TRS) and hardness of wc 9(Co 75%Ni) rare earth cemented carbides can match that of wc 9Co cemented carbide, when La 2O 3 / (Co+Ni) ratio is 0.3%, the abnormal growth of wc grain in the cemented carbide can be restrained effectively, the homogeneity of grain size in microstructure and the wear resistance are improved, which can be matchable to that of wc 9Co cemented carbide for mining.

关键词： cemented carbide rare earth cobalt substitution application

Ab Initio Molecular Dynamic Simulation on the Elasticity of Mg_3Al_2Si_3O_(12) Pyrope

在线全文

学校读者我要写书评

暂无评论

Journal of Earth Science 2011年第2期22卷 169-175页

作者： li li Donald J Weidner John Brodholt Dario Alfe G David Price Mineral Physics Institute Department of Geosciences University of New York at Stony Brook Stony Brook NY 11790 USA Department of Earth Sciences University College London Gower Street London WC1E6BT UK

We calculated thermo-elastic properties of pyrope（Mg3Al2Si3O12） at mantle pressures and temperatures using Ab initio molecular dynamic simulation.A third-order Birch-Murnaghan equation at a reference temperature of 2 000 K fits the calculations with bulk modulus,K0=159.5 GPa,K0＇=4.3,V0=785.89 A3,Grüneisen parameter,γ0=1.15,q=0.80,Anderson Grüneisen parameter δT=3.76 and thermal expansion,α0=2.93×10^-5 K^-*** to room temperature,where V0=750.80 A3,γ0 and α0 become 1.11 and 2.47×10^-5 K^-*** elastic properties of pyrope are found to be nearly isotropic at transition zone conditions.

关键词： AIMD thermo-elasticity pyrope high pressure.

A bioinspired bubble removal method in microchannels based on angiosperm xylem embolism repair

在线全文

学校读者我要写书评

暂无评论

Microsystems & Nanoengineering 2022年第2期8卷 237-247页

作者： lihua Guo Yuanchang liu Penghui Ran Gang Wang Jie Shan Xudong li Chong liu Jingmin li Key Laboratory for Micro/Nano Technology and System of liaoning Province Dalian University of TechnologyDalianChina Department of Mechanical Engineering University College LondonTorrington PlaceLondon WC1E 7JEUK

It is difficult to remove and eliminate bubbles in microchannels in many devices used in various biomedical fields,such as those needed for microfluidic immunoassays,point-of-care testing,and cell biology *** bubbles are associated with a number of negative outcomes,including a decrease in device sensitivity,inaccuracy of analysis results,and even functional *** conduits of angiosperm have the ability to remove bubbles in obstructed *** by such an embolism repair mechanism,this paper proposes a bioinspired bubble removal method,which exhibits a prominent ability to dissolve bubbles continuously within a large range of flow rates(2μL/min-850 plVmin)while retaining the stability and continuity of the flow without auxiliary *** a method also shows significant bubble removal stability in dealing with Newtonian liquids and non-Newtonian fluids,especially with high viscosity(6.76 Pa s)and low velocity(152 nL/min).Such advantages associated with the proposed bioinspired method reveal promising application prospects in macro/microfluidic fields ranging from 3D printing,implantable devices,virus detection,and biomedical fluid processing to microscale reactor operation and beyond.

关键词： bubble remove method

Advances in particulate matter filtration:Materials,performance,and application

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

Green Energy & Environment 2023年第3期8卷 673-697页

作者： Xuzheng Ji Jianying Huang lin Teng Shuhui li Xiao li Weilong Cai Zhong Chen Yuekun Lai College of Chemical Engineering Fuzhou UniversityFuzhou350116China b Qingyuan Innovation Laboratory Quanzhou362801China Department of Chemistry University College LondonLondonWC1H 0AJUK School of Materials Science and Engineering Nanyang Technological University50 Nanyang AvenueSingapore

Air-borne pollutants in particulate matter(PM)form,produced either physically during industrial processes or certain biological routes,have posed a great threat to human *** during the current COVID-19 pandemic,effective filtration of the virus is an urgent matter *** this review,we first introduce some fundamentals about PM,including its source and classification,filtration mechanisms,and evaluation *** filtration materials and their functions are then summarized,among which polymers and MOFs are discussed in detail together with their antibacterial *** discussion on the application is divided into end-of-pipe treatment and source ***,we conclude this review with our prospective view on future research in this area.

关键词： Air filtration PM capture End-of-pipe treatment Source control COVID-19