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Effects of Al addition on bainite transformation and properties of high-strength carbide-free bainitic steels

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Journal of Iron and Steel Research International 2019年第8期26卷 846-855页

作者： jun-yu Tian Guang Xu Ming-xing Zhou hai-jiang hu Zheng-liang Xue The State Key Laboratory of Refractories and Metallurgy Hubei Collaborative Innovation Center for Advanced Steels Wuhan University of Science and Technology Wuhan 430081 Hubei China

The effects of aluminum addition on bainite transformation and properties of carbide-free bainitic steels containing 0.22 wt.% carbon were investigated by two different types of heat treatment processes: continuous cooling process (CCP) and isothermal transformation process (ITP). The results indicate that for the CCP treatment, Al addition significantly promoted the ferrite and bainite transformation;however, it did not significantly increase the product of tensile strength and total elongation (PSE). For the ITP treatment, Al addition significantly promoted the kinetics of bainite transformation, and thus, more bainite was formed with Al addition;however, it was found that Al addition resulted in a decrease in tensile strength and an increase in elongation of the tested bainitic steels. Moreover, the effects of Al addition on comprehensive property were profoundly dependent on austempering temperatures. When the austempering temperature was higher (430℃), PSE significantly increased with Al addition, whereas it decreased at the lower austempering temperature (400℃). Therefore, it can be concluded that the effects of Al on properties of bainitic steels were more significant at higher austempering temperatures.

关键词： Aluminum Bainite transformation Continuous cooling Isothermal transformation Mechanical property

Proppant transport in rough fracture networks using supercritical CO_(2)

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Petroleum Science 2024年第3期21卷 1852-1864页

作者： Yong Zheng Meng-Meng Zhou Ergun Kuru Bin Wang jun Ni Bing Yang Ke hu hai huang hai-Zhu Wang School of Petroleum Engineering Xi'an Shiyou UniversityXian710065ShaanxiChina Shaanxi Key Laboratory of Carbon Dioxide Sequestration and Enhanced Oil Recovery Xi'an710075ShaanxiChina State Key Laboratory of Petroleum Resources and Engineering China University of Petroleum(Beijing)Beijing2249China School of Mining and Petroleum Engineering University of AlbertaEdmontonTG2W2AlbertaCanad Shaanxi Yanchang Petroleum(Group)Co. Ltd.Xi'an710075ShaanxiChina

Proppant transport within fractures is one of the most critical tasks in oil,gas and geothermal reservoir stimulation,as it largely determines the ultimate performance of the operating *** transport in rough fracture networks is still a relatively new area of research and the associated transport mechanisms are still *** this study,representative parameters of rough fracture surfaces formed by supercritical CO_(2) fracturing were used to generate a rough fracture network model based on a spectral synthesis *** fluid dynamics(CFD)coupled with the discrete element method(DEM)was used to study proppant transport in this rough fracture *** reveal the turning transport mechanism of proppants into branching fractures at the intersections of rough fracture networks,a comparison was made with the behavior within smooth fracture networks,and the effect of key pumping parameters on the proppant placement in a secondary fracture was *** results show that the transport behavior of proppant in rough fracture networks is very different from that of the one in the smooth fracture *** turning transport mechanisms of proppant into secondary fractures in rough fracture networks are gravity-driven sliding,high velocity fluid suspension,and fracture structure *** the same injection conditions,supercritical CO_(2)with high flow Reynolds number still has a weaker ability to transport proppant into secondary fractures than *** of the supercritical CO_(2)needs to be increased beyond a certain value to have a significant effect on proppant carrying,and under the temperature and pressure conditions of this paper,it needs to be increased more than 20 times(about 0.94 m Pa s).Increasing the injection velocity and decreasing the proppant concentration facilitates the entry of proppant into the branching fractures,which in turn results in a larger stimulated reservoir *** results help to understand the pro

关键词： Reservoir stimulation CCUS Rough fracture network Supercritical CO_(2) Proppanttransport

Effects of a novel refiner Al-3Ti-4.35La combined with Sr on microstructure and mechanical properties of as-cast A356 alloy

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China Foundry 2024年第6期21卷 641-650页

作者： Mei Xu Wan-wu Ding Li-wen hu Shi-hao Chen hai-xia Zhang hai-cun Yu Wen-jun Zhao School of Materials Science and Engineering Lanzhou University of TechnologyLanzhou 730050China State Key Laboratory of Advanced Processing and Recycling of Nonferrous Metals Lanzhou University of TechnologyLanzhou 730050China

It is a practically significant issue to refine and modify industrial Al-Si casting alloy to improve its *** the present study,a novel refiner Al-3Ti-4.35La alloy,prepared by a melt-reaction method,was used,combined with Sr to refine the as-cast A356 *** effects on the as-cast microstructures and mechanical properties of A356 alloy were *** results indicate that the combined addition of Al-3Ti-4.35La intermediate alloy and Sr can improve the microstructure and enhance the mechanical properties of A356 *** adding 0.3wt.%Al-3Ti-4.35La and 0.03wt.%Sr to the as-cast A356 alloy,the average grain size ofα-Al decreases from 693.47μm to 264.13μm(a decrease of 61.91%),the secondary dendrite arm spacing(SDAS)is decreased by 47.8%from 32.09μm to 16.75μm,and the eutectic Si is transformed from an acicular structure to short rods and a granular *** ultimate tensile strength(UTS)and elongation(EL)of the as-cast A356 alloy modified by Al-3Ti-4.35La and Sr reach 216.3 MPa and 10.6%,which are enhanced by 29.54%and 134.66%compared with the unmodified alloy,*** fracture mode is transformed from transgranular fracture to intergranular fracture,and the ductile toughness of the alloy is *** adding the Al-3Ti-4.35La and Sr,the undercooling for the nucleation ofα-Al and eutectic Si increases,leading to an accelerated nucleation rate and an increased number of nuclei,which shortens the duration of the eutectic reaction and consequently inhibits grain growth.

关键词： A356 alloy Al-3Ti-4.35La Sr refiner grain refinement microstructure mechanical properties

Experimental investigation of flow past a circular cylinder with hydrophobic coating

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Journal of Hydrodynamics 2018年第6期30卷 992-1000页

作者： jun Wen hai-bao hu Zhuang-zhu Luo Zhao-zhu Zhang School of Marine Science and Technology Northwestern Polytechnical University Chongqing Institute of Green and Intelligent Technology Chinese Academy of Sciences State Key Laboratory of Solid Lubrication Lanzhou Institute of Chemical Physics Chinese Academy of Sciences

A series of experiments are performed in a gravitational low-speed water tunnel to investigate the influence of the hydrophobic coating on the flow past a circular cylinder. The mean velocity and turbulence intensity profiles behind the cylinders are measured using the hot-film anemometer while the separation angles are obtained with the flow visualization technology. For the Reynolds number lower than 3 800, the hydrophobic coatings are in the Cassie state, the velocity deficit and the turbulence intensity in the wake of the hydrophobic cylinders are lower than those of the smooth cylinders which implies the drag reduction effect of the hydrophobic coatings. When the Reynolds number becomes higher than 6 600, the hydrophobic coatings turn into the Wenzel state. Through decomposing the velocity data in the turbulent wake into different scales based on the orthogonal wavelet transform, it is found that the total turbulence intensity in the wake of the hydrophobic cylinders becomes almost the same as in the wake of the smooth cylinders while the intensity of the large scales of vortex components in the wake of the hydrophobic cylinders is still lower. Furthermore, the separation angles show the same trend as a function of the Reynolds number but always take smaller values for the hydrophobic cylinders.

关键词： Hydrophobic coating drag reduction vortex structures separated flows

Preparation, Crystal Structure and Thermal Decomposition Process of Dysprosium Benzoate Complex with 1,10-Phenanthroline

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Chinese Journal of Structural Chemistry 2008年第2期27卷 233-237页

作者： XU Su-Ling ZHANG Jian-jun REN Ning ZHANG hai-Yan hu Rui-Sheng Experimental Center Hebei Normal UJziversity Shijiazhuang 050016 China Department of Engineering Shijiazhuang Foreign Economy and Trade Vocational College Shijiazhuang 050061 China Department of Chemistry Handan College Handan 056005 China School of Chemical Engineering Shijiazhuang College Shijiazhuang 050035 China

A dinuclear dysprosium（III） complex with benzoic acid and 1,10-phenanthroline, [Dy（BA）3phen]2 （BA = benzoate, PHEN = 1,10-phenanthroline）（C66H46Dy2NaO12, Mr = 1412.07） was synthesized and characterized by elemental analysis, UV, IR, X-ray diffraction, molar conductance and TG-DTG techniques. It crystallizes in triclinic, space group P1 with a = 10.773（2）, b = 11.933（3）, c = 12.417（5） A, α= 105.226（3）,β= 93.470（3）, γ= 113.475（2）°, V= 1388.0（7）, Z = 1, Dc = 1.689 g/cm3, μ（MoKa） = 2.742 mm-1 and F（000） = 698. R = 0.0210, wR = 0.0538. In the crystal, each Dy（III） ion is eight-coordinated by one bidentate chelating carboxylate group, four bidentate bridging carboxylate groups and one 1,10-phenanthroline molecule. The thermal decomposition process of [Dy（BA）3phen]2 has been determined by thermal analysis.

关键词： benzoic acid crystal structure 1,10-phenanthroline dysprosium complex thermal analysis

Synthesis and Characteristics of Electrodeposited CoxZn1-x Nanorods

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Chinese Physics Letters 2010年第6期27卷 203-205页

作者： LIU Li-hu GU Jian-jun LI hai-Tao CAI Ning SUN hui-Yuan College of Physics Science and Information Engineering Hebei Normal University Shijiazhuang 050016 Key Laboratory of Advanced Films of Hebei Province Shijiazhuang 050016 Department of Physics Hebei Chengde Teachers College Chengde 067000

CoxZn1-x nanorod arrays were fabricated by electrodeposition in porous anodic aluminum oxide templates at different electric potentials. X-ray diffraction and transmission electron microscopy indicate that highly-ordered and uniform nanorods have been fabricated. The amounts of Co and Zn contents are investigated using energy dispersive spectroscopy, which demonstrates that the atom ratio of the alloy nanorods changes with the deposition potential. In addition, magnetic measurements show that the magnetic isotropy Co-rich CoZn nanorods will change to magnetic anisotropy nanorods with the easy axis parallel to the rod long axis with decreasing Co content.

关键词： ELECTROFORMING MICROFABRICATION COBALT compounds POROUS materials ALUMINUM oxide X-ray diffraction MAGNETIC measurements ANISOTROPY

Global and regional burdens of oral cancer from 1990 to 2017:Results from the global burden of disease study

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Cancer Communications 2020年第2期40卷 81-92页

作者： Zhen-hu Ren Chuan-Yu hu hai-Rong He Yuan-Jie Li jun Lyu Department of Clinical Research The First Affiliated Hospital of Jinan UniversityGuangzhouGuangdong510632P.R.China Department of Oral and Maxillofacial&Head and Neck Oncology Shanghai Ninth People’s HospitalShanghai Jiao Tong University School of MedicineShanghai200011P.R.China Department of Oral and Maxillofacial Surgery Hainan West Central HospitalDanzhouHainan571700P.R.China Stomatology Center Tongji HospitalTongji Medical CollegeHuazhong University of Science and TechnologyWuhanHubei430030P.R.China School of Public Health Xi’an Jiaotong University Health Science CenterXi’anShaanxi710061P.R.China Department of human Anatomy Histology and EmbryologySchool of Basic Medical SciencesXi’an Jiaotong University Health Science CenterXi’anShaanxi710061P.R.China

Background:Data on the incidence,mortality,and other burden of oral cancer as well as their secular trends are necessary to provide policy-makers with the information needed to allocate resources *** purpose of this study was to use the Global Burden of Disease(GBD)2017 results to estimate the incidence,mortality,and disability-adjusted life years(DALYs)for oral cancer from 1990 to ***:We collected detailed data on oral cancer from 1990 to 2017 from the GBD *** global incidence,mortality,and DALYs attributable to oral cancer as well as the corresponding age-standardized rates(ASRs)were *** estimated annual percentage changes in the ASRs of incidence(ASRI)and mortality(ASRM)and age-standardized DALYs of oral cancer were also calculated according to regions and countries to quantify the secular trends in these ***:We tracked the incidence,mortality,and DALYs of oral cancer in 195 countries/territories over 28 ***,the incidence,mortality,and DALYs of oral cancer increased by about 1.0-fold from 1990 to *** ASRI of oral cancer showed a similar trend,increasing from 4.41 to 4.84 per 100,000 person-years during the study *** ASRM remained approximately stable at about 2.4 per 100,000 from 1990 to 2017,as did the age-standardized DALYs,at about 64.0 per 100,000 *** was highest in Pakistan(27.03/100,000,95%CI=22.13-32.75/100,000),followed by Taiwan China,and lowest in Iraq(0.96/100,000,95%CI=0.86-1.06/100,000).ASRM was highest in Pakistan(16.85/100,000,95%CI=13.92-20.17/100,000)and lowest in Kuwait(0.51/100,000,95%CI=0.45-0.58/100,000).Conclusions:The ASRI of oral cancer has increased slightly worldwide,while the ASRM and age-standardized DALY have remained ***,these characteristics vary between countries,suggesting that current prevention strategies should be reoriented,and much more targeted and specific strategies should be established in some countries to forestall the incre

关键词： Age-standardized rates Disability-adjusted life years Global Burden of Disease study Incidence Mortality Oral cancer

Research progress of slippage characteristic and gas film stability enhancement methods on biomimetic hydrophobic surfaces

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Journal of Hydrodynamics 2024年第1期36卷 87-101页

作者： Meng-zhuo Zhang hai-bao hu Liu-zhen Ren Lu-yao Bao jun Wen Luo Xie School of Marine Science and Technology Northwestern Polytechnical UniversityXi’an710072China Research and Development Institute of Northwestern Polytechnical University in Shenzhen Shenzhen518063China

The biomimetic hydrophobic surface is a potentially efficient underwater drag reduction method and the drag reduction mechanism of this kind of surface comes from the interfacial *** now,it is a hotspot to grasp the slippage characteristic and explore slippage enhancement *** paper not only summarizes our numerical simulation and experimental results of slippage characteristic at the solid-liquid interface(SLI)of hydrophobic surfaces(HS)and the gas-liquid interface(GLI)of superhydrophobic surfaces(SHS)in recent years,but also introduces some innovative methods that can effectively improve the gas film stability and drag reduction effect of ***,we used the molecular dynamics(MD)simulation method to figure out the effect of the solid-liquid interaction strength,the system temperature and the shear rate on the slippage of SLI,and expound their action mechanism from molecular ***,by MD and multibody dissipative particle dynamics(MDPD)method,the slippage behavior at the GLI was studied under the influence of the microstructure size and the flow driving *** proposed a new kind of hybrid slip boundary condition model to describe the slippage characteristic on *** addition,we found through experiment that a three-dimensional backflow will appear on the GLI under the interfacial adsorption of surfactants,and the backflow direction will reverse with the change of GLI ***,we put forward the wettability step structure and gas injection method to enhance the stability and drag reduction effect of the gas film on SHS.

关键词： Hydrophobic surface superhydrophobic surface interfacial slip underwater drag reduction

Data Bucket-Based Fragment Management for Solid State Drive Storage System

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Journal of Electronic Science and Technology 2020年第4期18卷 330-340页

作者： Wei Jiang jun-Long Wang Jin-Yu Zhan Jing-huan Yu hai-Bo hu School of Information and Software Engineering University of Electronic Science and Technology of ChinaChengdu 610054 Computer Science Department City University of Hong KongHong Kong 999077

The current storage mechanism considered little in data’s keeping *** can produce fragments of various sizes among data *** some cases,these fragments may be serious and harm system *** this paper,we manage to modify the current storage *** introduce an extra storage unit called data bucket into the classical data manage ***,we modify the data manage mechanism to improve our *** keeping data according to their visited information,both the number of fragments and the fragment size are greatly *** different data features and storage device conditions,we also improve the solid state drive(SSD)lifetime by keeping data into different *** show that our designs have a positive influence on the SSD storage density and actual service time.

关键词： Data structure erasing time fragment solid state driver(SSD)