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A three-dimensional numerical study on instability of sinusoidal flame induced by multiple shock waves

Acta Mechanica Sinica 2017年第2期33卷 316-326页

作者： xiao Chen Gang Dong hua Jiang Key Laboratory of Transient Physics Nanjing University of Science and Technology Nanjing 210094 China

The instabilities of a three-dimensional sinusoidally premixed flame induced by an incident shock wave with Mach = 1.7 and its reshock waves were studied by using the Navier-Stokes (NS) equations with a single-step chemical reaction and a high resolution, 9th-order weighted essentially non-oscillatory scheme. The computational results were validated by the grid independence test and the experimental results in the literature. The computational results show that after the passage of incident shock wave the flame interface develops in symmetric structure accompanied by large-scale transverse vortex structures. After the interactions by successive reshock waves, the flame interface is gradually destabilized and broken up, and the large-scale vortex structures are gradually transformed into small-scale vortex structures. The small-scale vortices tend to be isotropic later. The results also reveal that the evolution of the flame interface is affected by both mixing process and chemical reaction. In order to identify the relationship between the mixing and the chemical reaction, a dimensionless parameter, , that is defined as the ratio of mixing time scale to chemical reaction time scale, is introduced. It is found that at each interaction stage the effect of chemical reaction is enhanced with time. The enhanced effect of chemical reaction at the interaction stage by incident shock wave is greater than that at the interaction stages by reshock waves. The result suggests that the parameter can reasonably character the features of flame interface development induced by the multiple shock waves.

关键词： Shock wave Flame interface RM instability Chemical reaction Vortex structure

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Dilation and breakage dissipation of granular soils subjected to monotonic loading

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Acta Mechanica Sinica 2016年第6期32卷 1065-1074页

作者： Yifei Sun Yang xiao hua Ji Faculty of Engineering and Information Sciences University of Wollongong School of Civil and Transportation Engineering Hohai University College of Civil Engineering Chongqing University

Dilation and breakage energy dissipation of four different granular soils are investigated by using an energy balance equation. Due to particle breakage, the dilation curve does not necessarily pass through the origin of coordinates. Breakage energy dissipation is found to increase significantly at the initial loading stage and then gradually become stabilised. The incremental dissipation ratio between breakage energy and plastic work exhibits almost independence of the confining pressure. Accordingly, a plastic flow rule considering the effect of particle breakage is suggested. The critical state friction angle is found to be a combination of the basic friction between particles and the friction contributed by particle breakage.

关键词： Dilation Particle breakage Granular soil Energy dissipation

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Preparation and characterization of barium strontium titanate/silicon nanoporous pillar array composite thin films by a sol-gel method

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International Journal of Minerals,Metallurgy and Materials 2012年第8期19卷 762-767页

作者： Shun-hua xiao Wei-fen Jiang Co11ege of Chemistry and Bioengineering Key Laboratory of New Processing Technology for Nonferrous Metals and Materials (Ministry of Education) Guilin University of Technology Guilin 541004 China Department of Mathematics and Information Science North China Institute of Water Conservancy and Hydroelectric Power Zhengzhou 450011 China

Barium strontium titanate （Ba0.5Sr0.5TiO3, BST）/silicon nanoporous pillar array （Si-NPA） thin films were prepared by a spin-coating/annealing technique based on Si-NPA with micro/nano-structure. Both the isomer conversion of acetylacetone and the network structure combined by enol and Ti-alkoxide facilitate the formation of the BST sol and the subsequent crystallization. Before the perovskite BST begins to form, the intermediate phase （Ba, Sr）Ti2OsCO3 is found. The boundary between BST and Si-NPA is of clarity and little interface diffusion, disclosing that Si-NPA is an ideal template substrate in the preparation of multifunctional composite films.

关键词： barium strontium titanate silicon nanoporous materials composite films sol-gel process

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Molecular Dissection of Xylan Biosynthesis during Wood Formation in Poplar

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Molecular Plant 2011年第4期4卷 730-747页

作者： Chanhui Lee Quincy teng Ruiqin Zhong Zheng-hua Ye Department of Plant Biology University of Georgia Athens GA 30602 USA National Exposure Research Laboratory US Environmental Protection Agency Athens GA 30605 USA

Xylan, being the second most abundant polysaccharide in dicot wood, is considered to be one of the factors contributing to wood biomass recalcitrance for biofuel production. To better utilize wood as biofuel feedstock, it is crucial to functionally characterize all the genes involved in xylan biosynthesis during wood formation. In this report, we investigated roles of poplar families GT43 and GT8 glycosyltransferases in xylan biosynthesis during wood formation. There exist seven GT43 genes in the genome of poplar （Populus trichocarpa）, five of which, namely PtrGT43A, PtrGT43B, PtrGT43C, PtrGT43D, and PtrGT43E, were shown to be highly expressed in the developing wood and their encoded proteins were localized in the Golgi. Comprehensive genetic complementation coupled with chemical analyses demonstrated that overexpression of PtrGT43A/B/E but not PtrGT43C/D was able to rescue the xylan defects conferred by the Arabidopsis irx9 mutant, whereas overexpression of PtrGT43C/D but not PtrGT43A/B/E led to a complementation of the xylan defects in the Arabidopsis irx14 mutant. The essential roles of poplar GT43 members in xylan biosynthesis was further substantiated by RNAi down-regulation of GT43B in the hybrid poplar （Populus alba x tremula） leading to reductions in wall thickness and xylan content in wood, and an elevation in the abundance of the xylan reducing end sequence. Wood digestibility analysis revealed that cellulase digestion released more glucose from the wood of poplar GT43B RNAi lines than the control wood, indicating a decrease in wood biomass recalcitrance. Furthermore, RNAi down-regulation of another poplar wood-associated glycosyltransferase, PoGTSD, was shown to cause decreases in wall thickness and xylan content as well as in the abundance of the xylan reducing end sequence. Together, these findings demonstrate that the poplar GT43 members form two functionally non-redundant groups, namely PtrGT43A/B/E as functional orthologs of Arabidopsis IRX9 and PtrG

关键词： Glycosyltransferase GT8 family GT43 family poplar wood formation xylan.

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Assessment of bacterial biomass in the highly contaminated urban Nanming River,Guiyang,SW China

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Acta Geochimica 2017年第4期36卷 638-644页

作者： Hao xiao hua-Yun xiao Pan Wu Resource and Environmental Engineering College Guizhou University State Key Laboratory of Environmental Geochemistry Institute of GeochemistryChinese Academy of Sciences

High anthropogenic N loads and abundant bacteria are characteristic of highly contaminated urban *** better understand the dispersal and accumulation of bacteria, we determined contents and isotopic compositions of suspended particulate organic matter(SPOM) and bacteria in a highly contaminated urban river(the Nanming)and effluents in winter and summer of 2013. Relative to SPOM, bacterial biomass in the river was depleted in ^(13)C and ^(15)N and its C/N ratio was lower(δ^(13)C:-33.2% ± 3.1%; δ^(15)N:-1.5% ± 1.2%; C/N:4.8 ± 0.6), while effluents showed higher ^(13)C and ^(15)N contents and C/N ratios(δ^(13)C:-25% ± 2.1%; δ ^(15)N:-8.5% ± 1.1%; C/N: 8.1 ± 1.2). Source recognition of SPOM was based on carbon isotopes because they are conservative and distinct between end-members(effluent detritus and bacterial biomass). Using a mixing model,bacterial biomass in the river was calculated to account for <20% and <56% of bulk suspended particulate organic nitrogen in winter and summer, respectively. An N budget showed that bacterial N was a small proportion of total nitrogen(<7.4%) in the riverwater.

关键词： δ^13C δ^15C Bacterial biomass N budget Nanming River

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Study on Wave Dissipation of the Structure Combined by Baffle and Submerged Breakwater

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China Ocean Engineering 2017年第6期31卷 674-682页

作者： JU Lie-hong zuo Qi-hua teng Ling WANG Xing-gang Nanjing Hydraulic Research Institute Nanjing 210029 China College of Harbor Coastal and Offshore Engineering Hohai University Nanjing 210098 China Key Laboratory of Port Waterway and Sedimentation Engineering of the Ministry of Transport Nanjing 210029 China

This paper proposes a structure combined by baffle and submerged breakwater （abbreviated to SCBSB in the following texts）. Such a combined structure is conducive to the water exchange in the harbor, and has strong capability on wave dissipation. Our paper focuses on the discussion of two typical structures, i.e., the submerged baffle and rectangular breakwater combined with the upper baffle respectively, which are named as SCBSB 1 and SCBSB2 for short. The eigenfunction method corrected by experimental results is used to investigate the wave dissipation characteristics. It shows that the calculated results agree well with the experimental data and the minimum value of the wave transmission coefficient can be obtained when the distance between the front and rear structures is from 1/4 to 1/2 of the incident wave length.

关键词： combined wave dissipation structure eigenfunction method physical model experiment transmissioncoefficient correction wave dissipation effect

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Electrochemical deposition of Nd and Nd-Fe alloy from Cu6Nd alloy in a NaCl-KCl-NdCl3 melt

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International Journal of Minerals,Metallurgy and Materials 2020年第12期27卷 1650-1656页

作者： Chen-teng Sun Qian Xu Yan-ping xiao Yong-xiang Yang State Key Laboratory of Advanced Special Steel School of Material Science and EngineeringShanghai UniversityShanghai 200072China Department of Materials Science and Engineering Delft University of TechnologyDelft 2628 CDThe Netherlands Department of Metallurgical Engineering Anhui University of TechnologyMa'anshan 243002China

Electrorefining effectively separates metals from their corresponding *** obtain Nd from Cu6 Nd alloy,cyclic voltammetry and square wave voltammetry were used to investigate the reduction behavior of Nd^(3+) and the anode dissolution behavior of Cu6 Nd in the Na Cl-KCl-0.5 mol%Nd Cl3 melt at 1023 *** to the analysis of the electrochemical behavior,the cell voltage was determined to be between 0.3 and 1.2 V for separating Nd from Cu6 *** electrolysis at 0.6 V for 4 h,the Nd was found at the surface of the Mo cathode without any *** the Fe cathode,a deposition with an atom ratio of Nd:Fe=1:1 was formed on the ***,the low current density of separation remains a great experimental challenge that must be solved.

关键词： Cu6Nd alloy molten salt electrochemical separation NaCl-KCl-NdCl3

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Two-dimensional synthetic templates

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National Science Review 2015年第1期2卷 19-21页

作者： xiao huang hua Zhang Key Laboratory of Flexible Electronics (KLOFE) & Institute of Advanced Materials (IAM) Jiangsu National Synergistic Innovation Center for Advanced Materials (SICAM)Nanjing Tech University(Nanjing Tech) School of Materials Science and Engineering Nanyang Technological University

The isolation of atomic-thin graphene sheets from bulk graphite has led to the discovery of a number of novel properties of graphene that have enormously beneited the development of nanotechnology[1],which has inspired the exploration of other 2D materials,such as transition metal dichalcogenides(TMDs),hexagonal boron nitride(hBN),etc.[2].To exfoliate a layered bulk

关键词： Two-dimensional synthetic templates

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Vibration characteristics of multi-parametric excitations and multi-frequency external excitations of rolling mill under entry thickness fuctuation of strip

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Journal of Iron and Steel Research International 2020年第5期27卷 517-527页

作者： teng Xu Dong-xiao Hou Zheng-nan Sun Da-wu Guo School of Control Engineering Northeastern University at QinhuangdaoQinhuangdao 066004HebeiChina

A dynamic rolling force model with multi-parametric excitations and multi-frequency external excitations caused by entry thickness fuctuation of strip was *** on the dynamic rolling force,a nonlinear vertical vibration model with multi-parametric excitations and multi-frequency external excitations was *** method of multiple scales was used to solve the amplitude-frequency characteristic equation of primary resonance of the nonlinear vibration system of a rolling *** transition set and the topology structure of systematic global bifurcation were obtained by using the singularity ***,primary resonance characteristics of the system under entry thickness fuctuation of strip were analyzed by using actual parameters of the rolling *** global bifurcation curves with the change of amplitude and frequency of entry thickness fuctuation of strip were obtained by using numerical simulation,and many dynamic behaviors were found such as single-cycle motion,multi-cycle motion and chaotic motion,which can provide a theoretical reference for further restraining the vibration of a rolling mill.

关键词： Entry thickness fluctuation Dynamic rolling force Nonlinear vertical vibration Primary resonance Bifurcation

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Color control of the multi-color printing device

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2006年第7期7卷 1187-1192页

作者： WANG xiao-hua XIU xiao-jie ZHU Wen-hua TANG Hong-jun School of Computer Hangzhou Dianzi University Hangzhou 310018 China

Conventional color-printing systems often use inks of three hues, such as CMY, CMYK and CMYKLcLm, but in order to obtain more realistic color reproductions, the ink set of more than three hues has been adopted by some color-printing systems. It is difficult, however, to model the composed color with the multiple inks when the number of the output ink hues exceeds three due to the none-unique mapping between the color spaces of the CIE Lab and the multi-color printing device. In this paper, we propose a fine color-printing method for multi-color printing device with the ink set of more than three hues. The proposed approach has good color expression ability and provides fine control of the printed color. By dividing the output color space into several subspaces, our method allows one-to-one mapping between the standard color space and the multi-color output color space. It has been proved effective when applied to the digital inkjet printer—Mutoh8000.

关键词： Multi-color printing device Color gamut Color space Digital inkjet printer

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