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Augmented virtual environment: fusion of real-time video and 3D models in the digital earth system

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International Journal of Digital Earth 2017年第12期10卷 1177-1196页

作者： Hongdeng jian Jingjuan liao Xiangtao Fan Zhuxin Xue Key Laboratory of Digital Earth Science Institute of Remote Sensing and Digital EarthChinese Academy of SciencesBeijingPeople’s Republic of China University of Chinese Academy of Sciences BeijingPeople’s Republic of China Key Laboratory for Earth Observation of Hainan Province Sanya Institute of Remote SensingHainanPeople’s Republic of China

An Augmented virtual environment(AVE)is concerned with the fusion of real-time video with 3D models or scenes so as to augment the virtual *** this paper,a new approach to establish an AVE with a wide field of view is proposed,including real-time video projection,multiple video texture fusion and 3D visualization of moving objects.A new diagonally weighted algorithm is proposed to smooth the apparent gaps within the overlapping area between the two adjacent videos.A visualization method for the location and trajectory of a moving virtual object is proposed to display the moving object and its trajectory in the 3D virtual *** experimental results showed that the proposed set of algorithms are able to fuse multiple real-time videos with 3D models efficiently,and the experiment runs a 3D scene containing two million triangles and six real-time videos at around 55 frames per second on a laptop with 1GB of graphics card *** addition,a realistic AVE with a wide field of view was created based on the Digital Earth Science Platform by fusing three videos with a complex indoor virtual scene,visualizing a moving object and drawing its trajectory in the real time.

关键词： Augmented virtual environment Digital Earth Science Platform real-time video multiple video texture mapping and fusion moving object visualization

A compact streamfunction-velocity scheme for the 2-D unsteady incompressible Navier-Stokes equations in arbitrary curvilinear coordinates

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Journal of Hydrodynamics 2019年第4期31卷 827-839页

作者： jian-xin Qiu bo Peng Zhen-fu Tian Department of Mechanics and Engineering Science Fudan University Shanghai 200433 China

A streamfunction-velocity formulation-based compact difference method is suggested for solving the unsteady incompressible Navier-Stokes equations in the arbitrary curvilinear coordinates, in which the stream function and its first derivatives as the unknown variables are utilized. Numerical examples, involving the boundary layer problem, a constricted channel flow, driven polar cavity flow and trapezoidal cavity flow problem, are solved by the present method. Numerical results demonstrate the accuracy of the proposed scheme and exhibit the numerical capability to simulate the flow problems on geometries beyond rectangular. For driven polar cavity flow problem, the results show that the flow for Re = 5 000 is not steady but time-periodic, and the critical Reynold number (Rec) for the occurrence of a Hopf bifurcation is given.

关键词： Streamfunction-velocity formulation arbitrary curvilinear coordinates compact scheme unsteady incompressible flow

Application of biomonitoring and support vector machine in water quality assessment

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Journal of Zhejiang University-Science B(Biomedicine & Biotechnology) 2012年第4期13卷 327-334页

作者： Yue liao jian-yu XU Zhu-wei WANG Institute of Information Science and Technology Ningbo UniversityNingbo 315211China Cisco Systems(China)Research and Development Company Limited Hangzhou 310012China

The behavior of schools of zebrafish （Danio rerio） was studied in acute toxicity environments. Behavioral features were extracted and a method for water quality assessment using support vector machine （SVM） was de- veloped. The behavioral parameters of fish were recorded and analyzed during one hour in an environment of a 24-h half-lethal concentration （LC50） of a pollutant. The data were used to develop a method to evaluate water quality, so as 6＋ 2＋ to give an early indication of toxicity. Four kinds of metal ions （Cu2~, Hg2~, Cr , and Cd ） were used for toxicity testing. To enhance the efficiency and accuracy of assessment, a method combining SVM and a genetic algorithm （GA） was used. The results showed that the average prediction accuracy of the method was over 80% and the time cost was acceptable. The method gave satisfactory results for a variety of metal pollutants, demonstrating that this is an effective approach to the classification of water quality.

关键词： Water assessment Behavioral feature parameter Support vector machine (SVM) Genetic algorithm (GA) Water quality classification

Thermal analysis of walls in a new-type billet caster tundish with a vacuum shell

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Journal of Iron and Steel Research International 2017年第5期24卷 501-507页

作者： jian-bo Xie jian-an Zhou Lan-hua Zhou Bao Wang Hua Zhang State Key Laboratory of Refractories & Metallurgy Wuhan University of Science & Technology Wuhan 430081 Hubei China Key Laboratory of Ferrous Metallurgy and Resources Utilization Ministry of Education Wuhan University of Science & Technology Wuhan 430081 Hubei China School of Resources and Environmental Engineering Panzhihua University Panzhihua 617000 Sichuan China

To reduce thermal loss from molten steel in a tundish during continuous casting production, a new tundish fabricated by welding radiation-proof steel plates onto the steel plates of the exterior walls of a billet caster tundish was proposed. This new tundish was used to investigate the effect of pressures inside the vacuum chamber on the uniformity of the temperature of molten steel and the thermal conditions of the vacuum layer. The results show that the conversion radiation coefficient is not sensitive to pressure and its value at high temperatures is merely 1.5 times greater than that at low temperatures. Pressure is the key factor af- fecting additional factor of conversion convection. This factor is more than 100 times greater at 10-5 Pa than at 10-2 Pa, and the temperature at inner points at 10-2 Pa is, on average, 4 K higher than that at 10-5 Pa. Meanwhile, the local temperature difference of the inlet at 10-2 Pa is 1 K higher than that at 10-5 Pa. Thus, the proposed vacuum billet caster tundish can achieve low superheat teeming of steel because of the ther- mal preservation capability of the vacuum, which helps to reduce the tapping temperature and improve the uniformity of the temperature of steel.

关键词： Tundish Vacuum chamber Pressure Thermal preservation Superheat

Formation of interlayer gap and control of interlayer burr in dry drilling of stacked aluminum alloy plates

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Chinese Journal of Aeronautics 2016年第1期29卷 283-291页

作者： Tian Wei Hu jian liao Wenhe Bu Yin Zhang Lin College of Mechanical and Electronical Engineering Nanjing University of Aeronautics and Astronautics

In aircraft assembly, interlayer burr formation in dry drilling of stacked metal materials is a common problem. Traditional manual deburring operation seriously affects the assembly qual- ity and assembly efficiency, is time-consuming and costly, and is not conducive to aircraft automatic assembly based on industrial robot. In this paper, the formation of drilling exit burr and the influ- ence of interlayer gap on interlayer burr formation were studied, and the mechanism of interlayer gap formation in drilling stacked aluminum alloy plates was investigated, a simplified mathematical model of interlayer gap based on the theory of plates and shells and finite element method was established. The relationship between interlayer gap and interlayer burr, as well as the effect of feed rate and pressing force on interlayer burr height and interlayer gap was discussed. The result shows that theoretical interlayer gap has a positive correlation with interlayer burr height and preloading nressing force is an effective method to control interlaver burr formation.

关键词： Aircraft assembly Drilling Gap formation Interlayer burr Pressing force Stacked metal materials Thrust force

Experimental and analytical studies on the deformability of a precast RC shear wall involving bolted connections

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Science China(Technological Sciences) 2015年第8期58卷 1439-1448页

作者： SUN jian QIU HongXing YANG Yuan LU bo Key Laboratory of Concrete and Prestressed Concrete Structures of Ministry of Education Southeast University Suzhou Institute of Architectural Design Co.Ltd.

To study the deformability and ductility of an innovative precast shear wall joined by bolted connections,experimental tests were conducted on two test walls under monotonic and cyclic loading,respectively;subsequently,theoretical analysis was performed on the deformation performance of the shear wall *** test results confirmed the favorable deformability and ductility of the *** top displacement of the shear wall assembly was analytically decomposed into several constituent parts,the theoretical formulae of which were subsequently *** compositional analysis demonstrated that the top displacement of the test wall was primarily induced by the elastic deformation of the upper wall panel(UWP),the relative slippages within the bolted connections,and the flexural deformation within the plastic region of the UWP,while the constituent part contributed by the deformation in the connecting steel frame can be neglected.

关键词： precast shear wall bolted connections deformability analytical formulae

Development of Mixed Insulation Oil as Alternative Liquid Dielectric:A Review

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CSEE Journal of Power and Energy Systems 2024年第3期10卷 1242-1258页

作者： jian Hao Jingwen Zhang Wenyu Ye Ruijing liao Lijun Yang State Key Laboratory of Power Transmission Equipment Technology School of Electrical EngineeringChongqing UniversityChongqing 400044China IEEE CSEE

Use of traditional mineral oil(MO)as a liquid insulation in transformers has spanned more than 130 ***,MO has poor heat resistance,a low ignition point,and is a non-renewable resource,which does not meet development requirements for high-performance and environmentally friendly insulation ***,researchers have explored alternatives such as natural ester(NE)and synthetic ester(SE)oils,as well as mixed insulation *** insulating oil is a blend of diverse insulating oil types,with optimal performance achieved by adjusting proportions of base *** article summarizes the innovative achievements and development of mixed insulation oil in terms of development of mixed ratio,basic physical chemical properties,electrical properties,thermal stability,and application including operation and maintenance *** these efforts,this article aims to provide recommendations for future development of mixed insulating oils to advance liquid dielectric research based on enhancement mechanisms.

关键词： Environmentally friendly insulation oil ester oils high-performance mineral oil mixed insulation oils

Analysis of precipitation behavior of MnS in sulfur-bearing steel system with finite-difference segregation model

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Journal of Iron and Steel Research International 2018年第8期25卷 803-812页

作者： De-lin Hu Hui Liu jian-bo Xie Juan Cheng jian Li jian-xun Fu State Key Laboratory of Advanced Special Steel and Shanghai Key Laboratory of Advanced Ferrometallurgy and School of Materials Science and Engineering Shanghai University Shanghai 200444 China

To further reveal the influence of micro-segregation on the precipitation behavior of MnS in sulfur-bearing steel system, a coupled model of micro-segregation and MnS precipitation was established by the finite-difference method based on various calculation domains and the solid diffusion degrees, and a new controlled diffusion equation with more stable convergence was also used. 49MnVS3 and 1215 steels were used to analyze the influence of calculation domain, segregation model and S content on the precipitation behavior of MnS. The calculation results were verified by a high- temperature confocal laser scanning microscope （HT-CLSM）. The results show that the domain has little effect on the precipitation temperature, precipitation solid fraction and precipitation amount of MnS, but affects the precipitation location and segregation of the solutes. For low- and medium-sulfur steels, the temperatures calculated by the diffusion control growth （DCG） model and the Lever model were nearly identical, whereas the temperature calculated by the Scheil model was lower. However, for high-sulfur steels, the precipitation temperatures calculated by three segregation models were nearly same. The precipitation solid fraction is more reasonable to describe the precipitation behavior of MnS. The precipitation behavior of MnS, observed by the HT-CLSM, matches well with that in the DCG model.

关键词： MnS precipitation Micro-segregation Mathematical model Solidification In situ observation

Microstructure-ionisation potential relationship analysis for understanding the molecular ionisation difference of natural esters during the impulse discharge via DFT calculation

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High Voltage 2024年第4期9卷 920-929页

作者： Jingwen Zhang jian Hao Wenyu Ye Junyi Zhang Ruijin liao State Key Laboratory of Power Transmission Equipment Technology School of Electrical/EngineeringChongqing UniversityChongqingChina

Understanding the impulse discharge behaviour of natural ester(NE)is crucial for its safe application in high-voltage *** ionisation potential(IP)of triglycerides plays a significant role in the process of molecular ionisation during impulse discharge for *** correlation coefficients between molecular size,frontier orbital,electrostatic potential,polarity,and IP were *** the quantitative microstructure-IP model for triglycerides were built,which revealed that IP is strongly related to the highest occupied molecular orbital(HOMO)energy EHM,as well as the average value of positive electrostatic potential V_(p)(t),the average value of negative electrostatic potential V_(p)(-),and the surface area of negative electrostatic potential S(-).The HOMO and negative electrostatic potentials of saturated triglycerides are predominantly linked to the carbonyl O ***,in unsaturated triglycerides,the influence of C=C double bonds on HOMO and negative electrostatic potentials is more ***,the IP of unsaturated NE with C=C bonds is lower than that of saturated NE,rendering it more susceptible to ionisation under a strong electric field which is unfavourable for impulse breakdown *** structure-property correlation analysis is valuable for understanding ionisation mechanism during the impulse discharge breakdown of NE at the microscopic level.

关键词： electrostatic potential bonds