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Symmetries and solutions to geometrical flows

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Science China Mathematics 2013年第8期56卷 1689-1704页

作者： wang jinhua Center of Mathematical Sciences Zhejiang University

In this paper,we investigate group-invariant solutions to the hyperbolic geometric flow on Riemann surfaces,which include solutions of separation variables,traveling wave solutions,self-similar solutions and radial *** the proceeding of reduction,there are elliptic,hyperbolic and mixed types of *** the first kind of equation,some exact solutions are found;while for the last two kinds,with implicit solutions found,we furthermore investigate whether there will be a global solution or blowing *** to the work of Kong et al.(2009),the results come out perfectly.

关键词： geometrical flow exact solution symmetry blow up

EMBEDDINGS OF SIMPLE TWO-FOLD BALANCED INCOMPLETE BLOCK DESIGNS WITH BLOCK SIZE FOUR

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Chinese Annals of Mathematics,Series B 2005年第4期26卷 643-650页

作者： wang jinhua SHEN HAO School of Sciences Nantong University Nantong 226007 Jiangsu China. Department of Mathematics Shanghai Jiao Tong University Shanghai 200030 China.

The necessary and sufficient conditions for the existence of simple incomplete block design （v, ω; 4, 2）-IPBDs are determined. As a consequence, the necessary and sufficient conditions for the embeddings of simple ... 详细信息

关键词： Block design Simple Embedding

Convergence of the Newton method and uniqueness of zeros of vector fields on Riemannian manifolds

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Science China Mathematics 2005年第11期48卷 1465-1478页

作者： LI Chong wang jinhua Department of Mathematics Zhejiang University Hangzhou 310027 China Department of Mathematics Zhejiang University Hangzhou 310027 China

The estimates of the radii of convergence balls of the Newton method and uniqueness balls of zeroes of vector fields on the Riemannian manifolds are given under the assumption that the covariant derivatives of the vector fields satisfy some kind of general Lipschitz conditions. Some classical results such as the Kantorovich's type theorem and the Smale's γ-theory are extended.

关键词： Riemannian manifold,Newton method,convergence ball,uniqueness ball

The Recent Technological Development of Intelligent Mining in China

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Engineering 2017年第4期3卷 439-444页

作者： jinhua wang Zenghua Huang China Coal Technology and Engineering Group Beijing 100013 China

In the last five years, China has seen the technological development of intelligent mining and the application of the longwall automation technology developed by the Longwall Automation Steering Committee. This paper summarizes this great achievement, which occurred during the 12th Five-Year Plan （2011-2015）, and which included the development of a set of intelligent equipment for hydraulic-powered supports, information transfers, dynamic decision-making, performance coordination, and the achievement of a high level of reliability despite difficult conditions. Within China, the intelligent system of a set of hydraulic-powered supports was completed, with our own intellectual property rights. An intelligent mining model was developed that permitted unmanned operation and single-person inspection on the work face. With these technologies, the number of miners on the work face can now be significantly reduced. Miners are only required to monitor mining machines on the roadway or at the surface control center, since intelligent mining can be applied to extract middle-thick or thick coal seams. As a result, miners＇ safety has been improved. Finally, this Darter discusses theprospects and challenges of intelligent mining over the next ten years.

关键词： Coal mineIntelligent mining Mechanized mining work face Longwall Automation Steering CommitteeIntelligent service center

Development and validation of a three-dimensional,wave-current coupled model on unstructured meshes

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Science China(Physics,Mechanics & Astronomy) 2011年第1期54卷 42-58页

作者： wang jinhua SHEN YongMing State Key Laboratory of Coastal and Offshore Engineering Dalian University of Technology Dalian 116023 China

Using unstructured meshes provides great flexibility for modeling the flow in complex geomorphology of tidal creeks,barriers and islands,with refined grid resolution in regions of interest and not *** this paper,an unstructured three-dimensional fully coupled wave-current model is ***,a parallel,unstructured wave module is *** in wave properties are governed by a wave energy equation that includes wave-current interactions and dissipation representative of wave ***,the existing Finite-Volume Coastal Ocean Model(FVCOM) is modified to couple with the wave *** couple procedure includes depth dependent wave radiation stress terms,Stokes drift,vertical transfer of wave-generated pressure transfer to the mean momentum equation,wave dissipation as a source term in the turbulence kinetic energy equation,and mean current advection and refraction of wave *** applications are presented to evaluate the developed *** particular the wind and wave-induced storm surge generated by Hurricane Katrina is *** obtained results have been compared to the in situ measurements with respect to the wave heights and water level elevations revealing good accuracy of the model in reproduction of the investigated *** a comparison to water level measurements at Dauphin Island,inclusion of the wave induced water level setup reduced the normalized root mean square error from 0.301 to 0.257 m and increased the correlation coefficient from 0.860 to *** runs were carried out to analyze the effects of *** experiments show that among the processes that represent wave effects,radiation stress and wave-induced surface stress are more important than wave-induced bottom stress in affecting the water *** Hurricane Katrina simulations showed the importance of the inclusion of the wave effects for the hindcast of the water levels during the storm surge.

关键词： wave-current interactions three-dimensional model unstructured meshes radiation stress

A positively charged silver nanowire membrane for rapid on-site swabbing extraction and detection of trace inorganic explosives using a portable Raman spectrometer

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Nano Research 2016年第8期9卷 2487-2497页

作者： Yu-e Shi Wenshou wang jinhua Zhan National Engineering Research Center for Colloidal Materials and Key Laboratory of Colloid and Interface Chemistry of Ministry ofEducation Department of Chemistry Shandong University Jinan 250100 China

The sensitive and on-site detection of inorganic explosives has raised serious concerns regarding public safety. However, high stability and non-volatility features currently limit their rapid on-site detection. Surface-enhanced Raman spectroscopy （SERS） is emerging as a powerful technique for the trace-level detection of different molecules. Plasmonic Ag nanowires were produced by a hydrothermal synthesis method using polyvinylpyrrolidone （PVP） as a negatively charged stabilizer. Here, we report a rapid detection method for inorganic explosives based on a simple surface swab with a positively charged diethyldithiocarbamate-modified Ag nanowire membrane coupled with SERS. This membrane, serving as an excellent SERS substrate with high uniformity, stability, and reusability, can capture both typical oxidizers in inorganic explosives and organic nitro-explosives, via electrostatic interaction. The detection level of perchlorates （ClO4-）, chlorates （ClO3-）, nitrates （NO3）-, picric acid, and 2,4- dinitrophenol is as high as 2.0, 1.7, 0.1, 45.8, and 36.6 ng, respectively. In addition, simulated typical inorganic explosives such as black powders, firecrackers, and match heads could also be detected. We believe that this membrane represents an attractive alternative for rapid on-site detection of inorganic explosives with high efficiency.

关键词： Ag explosives nanowire surface-enhanced Ramanscattering on-site detection

Large Eddy Simulation Study on the Turbulence and Flame Characteristics under Analogical Integral Scale and Turbulence Intensity of Turbulent Premixed Flames

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Journal of Thermal Science 2023年第1期32卷 488-501页

作者： WEI Xutao wang jinhua ZHANG Meng HUANG Zuohua State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong UniversityXi'an 710049China

Bunsen burner is a typical geometry for investigating the turbulence-flame *** most experimental studies,only turbulence intensity u′and integral scale l0 are used to characterize the turbulent flow field,regardless of the perforation geometry of perforated ***,since the geometry influences the developing process and vortex broken,the plate geometry has to be considered when discussing the flame-turbulence *** order to investigate conditions at the same l0 and u′using different geometries,large eddy simulation of CH_(4)/air flames with dynamic TF combustion model was *** model validation shows good agreement between Large Eddy Simulation(LES)and experimental *** the non-reacting flows,the Vortex Stretching of circular-perforated plate condition is always larger than that of slot-perforated plate condition,which comes from the stresses in the flow fields to stretch the vorticity *** reacting flows,at the root of the flame,the Vortex Stretching plays a major role,and the total vorticity here of circular-perforated plate condition is still larger(53.8%and 300%larger than that of the slot-perforated plate at x/D=0 and x/D=2.5,respectively).More small-scale vortex in circular-perforated plate condition can affect and wrinkle the flame front to increase the Probability Density Function(PDF)at large *** 3D curvature distributions of both cases bias to negative *** negative trend of curvatures at the instant flame front results from the Dilatation ***,the value of the Vortex Stretching and the Dilatation at the flame front of circular-perforated plate condition is obviously larger.

关键词： large eddy simulation integral scale turbulence intensity vorticity flame curvature

Development and prospect on fully mechanized mining in Chinese coal mines

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International Journal of Coal Science & Technology 2014年第3期1卷 253-260页

作者： jinhua wang China Coal Technology&Engineering Group Corp. Beijing 100013China

Fully mechanized mining(FMM)technology has been applied in Chinese coal mines for more than 40 *** present,the output of a FMM face has reached 10-million tons with Chinese-made *** this study,the new developments in FMM technology and equipment in Chinese coal mines during past decades are *** automatic FMM technology for thin seams,complete sets of FMM technology with ultra large shear height of 7 m for thick seams,complete sets of fully mechanized top coal caving technology with large shear height for ultra-thick seams of 20 m,complete sets of FMM technology for complex and difficult seams,including steeply inclined seams,soft coal seams with large inclination angle,and the mechanized filling mining technology and equipment are *** typical case studies are also ***,the existing problems with the FMM technology are discussed,and prospect of FMM technology and equipment applied in Chinese coal mines is put forward.

关键词： Fully mechanized mining Mining with large shear height Fully mechanized top coal caving Steeply inclined seam Back filling mining Prospect

A review of engine application and fundamental study on turbulent premixed combustion of hydrogen enriched natural gas

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Science China(Technological Sciences) 2014年第3期57卷 445-451页

作者： wang jinhua WEI ZhiLong ZHANG Meng HUANG ZuoHua State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University

The application and fundamental study on turbulent premixed combustion of hydrogen enriched natural gas is reviewed in this *** include the combustion characteristics of direct injection engine fueled with hydrogen enriched natural gas,visualization study of direct injection combustion of hydrogen enriched natural gas using a constant volume vessel,and the fundamental study of turbulent premixed combustion of hydrogen enriched natural *** effect of additional hydrogen on the combustion process of natural gas engine is investigated from the fundamental view of the interaction between combustion reaction and turbulent flow.

关键词： natural gas hydrogen direct injection combustion turbulent premixed combustion OH-PLIF engine