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Preparation of Ultrafine Tungsten Powder by Sol-Gel Method

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Journal of Materials Science & Technology 2008年第5期24卷 816-818页

作者： Yuxian HAN Tai qiu tao SONG College of Materials Science and Engineering Nanjing University of Technology Nanjing 210009 China

Sol-gel method was employed for the preparation of nanoscale tungsten powder. The effects of different preparation conditions on particle size were discussed and the optimum preparation condition was found. The products were characterized by X-ray diffraction, scan electron microscopy and so on. The results show that the intermediate is monoclinic WO3, its particle shape is approximately spherical, and the particle size distribution is narrow. The average particle size is about 60 nm. After deoxidization, WO3 turns into cubic tungsten powder with small particle size （average particle size about 120 nm） and narrow size distribution.

关键词： Sol-gel method Tungsten trioxide Deoxidize Ultra-fine tungsten powder

Growth kinetics and mechanism of microarc oxidation coating on Ti-6Al-4V alloy in phosphate/silicate electrolyte

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International Journal of Minerals,Metallurgy and Materials 2022年第11期29卷 1991-1999页

作者： Dajun Zhai tao qiu Jun Shen Keqin Feng College of Materials Science and Engineering Chongqing UniversityChongqing 400044China School of Mechanical Engineering Sichuan UniversityChengdu 610065China

Microarc oxidation(MAO)is an effective surface treatment method for Ti alloys to allow their application in extreme ***,binary electrolytes consisting of different amounts of sodium phosphate and sodium silicate were designed for *** surface morphology,composition,and properties of MAO coatings on Ti-6Al-4V alloy treated in 0.10 mol/L electrolyte were investigated to reveal the effect of PO_(4)^(3-)and SiO_(3)^(2-)ray diffraction,and potentiodynamic *** results showed that PO_(4)^(3-)is beneficial for generating microarcs and forming pores within the coating,resulting in a thick but porous ***_(3)^(2-)eration of microarcs,resulting in a thin dense *** thickness,density,phases content,and polarization resistance of the MAO coatings are primarily affected by the intensity of microarcs for low SiO_(3)^(2-)ciently *** thickness of MAO coatings obtained in P/Si electrolytes shows a piecewise linear increase with increasing process time during the three stages of microarc ***_(3)^(2-)discharge,but slows down the growth of the coating formed in the next stage.

关键词： microarc oxidation titanium alloy phosphate silicate growth kinetics growth mechanism

基于PCA-BPNN的桥梁爆炸荷载时程预测

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爆炸与冲击 2025年第03期45卷 79-93页

作者：杜晓庆何益平邱涛程帅张德志上海大学力学与工程科学学院西北核技术研究所

人工智能方法是预测爆炸荷载的新手段，但现有方法主要用于预测爆炸冲击波的超压峰值或冲量，而用于预测反射超压时程的研究不多。针对这一问题，以平面冲击波绕射桥梁主梁为对象，提出了一种基于主成分分析（principal components anal... 详细信息

人工智能方法是预测爆炸荷载的新手段，但现有方法主要用于预测爆炸冲击波的超压峰值或冲量，而用于预测反射超压时程的研究不多。针对这一问题，以平面冲击波绕射桥梁主梁为对象，提出了一种基于主成分分析（principal components analysis, PCA）和误差反向传播神经网络（backpropagation neural network, BPNN）的桥梁爆炸冲击波反射超压时程预测模型。该预测模型利用PCA降维处理时程数据，基于多任务学习的BPNN算法，提出了考虑超压峰值和冲量峰值影响的损失函数，使模型能有效预测不同入射超压下的桥梁冲击波荷载时程。通过分析多任务学习模型、多输入单输出模型和多输入多输出模型等3种BPNN模型，发现多任务学习模型的预测精度最高，而多输入多输出模型难以有效适应当前预测任务需求。采用多任务学习模型预测得到的桥梁表面各测点位置的反射超压时程、超压峰值精度较高，决定系数R2分别为0.792和0.987，作用在箱梁上的合力时程和扭矩时程预测值也与数值模拟值较为吻合。同时，该模型对内插值预测的表现优于外推值预测，但其在预测外推值方面同样展现出了一定的能力。

关键词：爆炸荷载预测反射超压时程误差反向传播神经网络主成分分析多任务学习

FINITE ELEMENT ANALYSIS OF CARDIAC MYOCYTE DEBONDING AND REORIENTATION DURING CYCLIC SUBSTRATE STRETCH EXPERIMENTS

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Acta Mechanica Solida Sinica 2009年第4期22卷 307-319页

作者： tao Tang Jun qiu Meng Zhang Zhuo Zhuang School of Aerospace Tsinghua University Beijing 10084 China

The substrate stretch experiment, which is carried out on several kinds of adherent cells, is usually used to catch the physiological variation and morphological response to cyclic substrate deformation. In this paper, stretch loading was exerted on cardiac myocytes cultured on silica substrates using a custom-made substrate stretch device. The effect of stretch on the alignment orientation of cardiac myocytes was studied through morphocytological statistics. Under cyclic stretch stimulus, the long axes of cardiac myocytes oriented perpendicularly to the stretch direction for continuous stretch acting. However, the mechanism underlying these behaviors is not well understood from such in vitro tests. Finite element （FE） model was developed in the analysis to investigate these behaviors. Xu-Needleman formulation was used to define the interaction behavior for contact surfaces between cell and substrate. The role of cell viscoelasticity nature is studied in adherent cell debonding with the substrate and aligning perpendicular to the stretch direction during long time cyclic stretch stimulation. There were four different strain magnitudes considered in the simulation to find out the cell debonding affected by the cyclic strains. The potential role of cyclic strain frequency in regulating cell debonding and alignment was also studied using FE analysis.

关键词： cardiac myocyte cyclic substrate stretch cell adhesion finite element

Surface microstructure control of microalloyed steel during slab casting

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Journal of Iron and Steel Research International 2017年第8期24卷 803-810页

作者： Li-jun Xu Shu-lan Zhang Chun-gen qiu Sheng-tao qiu Xing-zhong Zhang Central Iron and Steel Research Institute Beijing 100081China

Lots of work has been done to investigate slab surface microstructure evolution during continuous casting in order to improve hot ductility and avoid transverse *** slab surface microstructure after continuous casting was characterized by optical microscopy,and the precipitation behavior was investigated by transmission electron *** the same time,the mechanical properties of the slabs were measured using a Gleeble 1500 Dthermal simulator and the transformation temperatures were examined by means of a thermal *** experimental results show that homogeneous microstructure without film-like ferrites and chain-like precipitates at grain boundary can be obtained through surface intensive cooling and transverse cracks do not occur on the slab *** the experimental steel,fine ferrite can form at slab surface when the water flow rate is larger than 1560L/min at vertical *** the distance to surface increases,microstructure turned to ferrite and ***,nano-size carbonitrides precipitated in the ferrite grain and the size was larger at the junction of the *** mechanical experiment results show that the hot ductility of the sample deformed at 650°C was better than that of the sample deformed at 750°*** reason is that filmlike ferrite formed at the grain boundary in the sample deformed at 750°***,the slab must be cooled quickly below Ar3 to prevent the occurrence of film-like ferrite and transverse cracks on the slab surface during casting.

关键词： Microalloyed steel Surface intensive cooling Ferrite Carbonitride Crack

Empirical Likelihood for Response Differences in Two Linear Regression Models with Missing Data

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Acta Mathematicae Applicatae Sinica 2015年第4期31卷 963-976页

作者： Yong-song QIN tao qiu Qing-zhu LEI Department of Mathematics Guangxi Normal University Guilin

Oonsider two linear models Xi = U＇β ＋ ei, Yj = V1/2y ＋ ηj with response variables missing at random. In this paper, we assume that X, Y are missing at random （MAR） and use the inverse probability weighted imputation to produce ＇complete＇ data sets for X and Y. Based on these data sets, we construct an empirical likelihood （EL） statistic for the difference of X and Y （denoted as A）, and show that the EL statistic has the limiting distribution of X~, which is used to construct a confidence interval for A. Results of a simulation study on the finite sample performance of EL-based confidence intervals on A are reported.

关键词： linear model inverse probability weighted imputation empirical likelihood missing at random confidence interval

Numerical simulation of fluid flow and alloy melting in RH process for electrical steels

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Journal of Iron and Steel Research International 2022年第9期29卷 1423-1433页

作者： Haijun Wang Rui Xu Hai-tao Ling Wei Zhong Li-zhong Chang Sheng-tao qiu Anhui Province Key Laboratory of Metallurgical Engineering and Resources Reeyeling Anhui University of TechnologyMa'anshan 243002AnhuiChina School of Metalurgical Engineering Anhui University of Technology.Ma'anshan 243002AnhuiChina State Key Laboratory of Advanced Metallurgy University of Science and Technology BeijingBeijing 100083China Xinyu Iron and Steel Co. Ltd.Xinyu 338001JiangxiChina National Engineering and Research Centerfor Continuous Casting Technology Central Iron and Steel Research InstituteBeijing 100081China

Based on the Eulerian-Lagrangian approach,a mathematical model was established to describe the gas-liquid flow behavior in the Ruhrstahl-Heraeus(RH)*** momentum source and the turbulent kinetic energy source due to the motion of gas bubbles were considered for the liquid *** effect of the expansion of gas bubbles on the liquid velocity,recirculation rate,and mixing time was quantitatively *** the fluid flow reached the steady state,the melting and mixing processes of aluminum alloys in the RH degasser were also *** results indicate that the expansion of gas bubbles has a significant infuence on the recirculation rate and the mixing time in the RH *** the superheat of liquid steel and decreasing the initial diameter of alloy particles are beneficial to promote the melting and mixing of alloy *** to the existence of solidified steel shells,the maximum diameter of the alloy particle is about 1.5 times its initial diameter.

关键词： Discrete particle model Multiphase flow Gas expansion-Mixing time Alloy melting Numerical simulation

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基于5G和融合通信技术的应急指挥调度系统

长江信息通信 2025年第1期38卷 234-237页

作者：张聚明杨光任燕邱涛广州广哈通信股份有限公司广东广州510663

在充分理解应急场景需求和智慧应急管理新格局发展趋势的情况下,文章基于5G和多制式一体化融合通信的应急组网技术,采用分离部署设计,将系统分为后方应急指挥中心业务调度处理系统、前方指挥部通信系统和应急现场。系统支持5G高清音视... 详细信息

在充分理解应急场景需求和智慧应急管理新格局发展趋势的情况下,文章基于5G和多制式一体化融合通信的应急组网技术,采用分离部署设计,将系统分为后方应急指挥中心业务调度处理系统、前方指挥部通信系统和应急现场。系统支持5G高清音视频通话,基于边缘智能计算框架支持边云一体协同,支持“一张图”可视化展示、全面感知预警风险隐患,实现音视频调度、会议会商、视频融合、GIS地图定位等多媒体指挥调度,可以多级部署、协同调度,解决应急救援现场各种通信手段互联互通差、缺乏联动机制、资源共享欠缺等弊端,全面提高应急指挥调度响应效率。

关键词：智慧应急 5G 融合通信应急指挥调度

Epigenetic regulation of mesenchymal stem cell aging through histone modifications

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Genes & Diseases 2023年第6期10卷 2443-2456页

作者： Yanping Sun Haoyu Zhang tao qiu Li Liao Xiaoxia Su State Key Laboratory of Oral Diseases&National Clinical Research Center for Oral Diseases&Department of Pediatrics&Engineering Research Center of Oral Translational Medicine Ministry of EducationWest China Hospital of StomatologySichuan UniversityChengduSichuan 610041China

Stem cell senescence and exhaustion,a hallmark of aging,lead to declines in tissue repair and regeneration in aged *** evidence has revealed that epigenetic regulation plays critical roles in the self-renew,lineage-commitment,survival,and function of stem ***,epigenetic alterations are considered important drivers of stem cell dysfunction during *** this review,we focused on current knowledge of the histone modifications in the aging of mesenchymal stem cells(MSCs).The aberrant epigenetic modifications on histones,including methylation and acetylation,have been found in aging *** disturbing the expression of specific genes,these epigenetic modifications affect the self-renew,survival,and differentiation of MSCs.A set of epigenetic enzymes that write or erase these modifications are critical in regulating the aging of ***,we discussed the rejuvenation strategies based on epigenetics to prevent stem cell aging and/or rejuvenate senescent MSCs.

关键词： Aging Epigenetic Histone acetylation Histone methylation Mesenchymal stem cell