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Design formulas of transmission coefficients for permeable breakwaters

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Water Science and Engineering 2014年第4期7卷 457-467页

作者： su-xiang ZHANG Xi LI Key Laboratory of Meteorological Disaster of Ministry of Education Nanjing University of Information Science and Technology Department of Civil Engineering and Applied Mechanics McGill University College of Harbor Coastal and Offshore EngineeringHohai University

New empirical formulas of the transmission coefficient for permeable breakwaters were suggested based on available experimental data regarding the low-crest structure （LCS）, including the permeable rubble mound breakwater and pile-type breakwater. The rationality of the present formulas was verified by their comparison with existing empirical and analytical formulas. Numerical flume results were obtained by solving the modified Boussinessq-type wave equations （MBEs）, and a new expression relating the friction coefficient of to the relative submerged depth Rt/H8 was also derived. Comparative analysis shows that the results of the present formulas agree with the numerical flume results as well as available experimental data, and the present formulas are superior to the existing empirical and analytical expressions in estimating the transmission coefficient. The present formulas can provide references for estimation of the transmission coefficient in engineering practice.

关键词： permeable breakwater transmission coefficient wave reflection nonlinear wave Boussinesq wave model low-crest structure

A numerical study of cavitating flows in high-pressure diesel injection nozzle holes using a two-fluid model

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Chinese Science Bulletin 2009年第10期54卷 1655-1662页

作者： WANG xiang su WanHua State Key Laboratory of Engines Tianjin University Tianjin 300072 China

Cavitating flows inside a diesel injection nozzle hole were simulated using a two-fluid model. Attention was focused on the complex cavitation processes and flow characteristics under constant inlet pressure and fluctuant inlet pressure modes. To validate the two-fluid model, model predictions were compared with the experimental data available in the literatures, and good agreement was achieved. The numerical results show that the appearance of supercavitation in the diesel nozzle hole induces obvious changes of flow field structures and exit flow conditions. The distributions of liquid phase turbulent kinetic energy and exit velocity profiles corresponding to the supercavitation regime indicate the potential for promoting the primary breakup of a diesel jet. Furthermore, the upstream pressure fluctuations significantly influence the cavitation processes. Both partial cavitation and supercavitation show unsteady behaviors as the rapid rise or fall of upstream pressure.

关键词：柴油机喷油规律换气过程做功原理

Convergence analysis of a nonlinear Lagrange algorithm for general nonlinear constrained optimization problems

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Applied Mathematics(A Journal of Chinese Universities) 2014年第3期29卷 352-366页

作者： HE su-xiang WU Li-xun School of Science Wuhan University of Technology

The convergence analysis of a nonlinear Lagrange algorithm for solving nonlinear constrained optimization problems with both inequality and equality constraints is explored in detail. The estimates for the derivatives of the multiplier mapping and the solution mapping of the proposed algorithm are discussed via the technique of the singular value decomposition of matrix. Based on the estimates, the local convergence results and the rate of convergence of the algorithm are presented when the penalty parameter is less than a threshold under a set of suitable conditions on problem functions. Furthermore, the condition number of the Hessian of the nonlinear Lagrange function with respect to the decision variables is analyzed, which is closely related to efficiency of the algorithm. Finally, the preliminary numericM results for several typical test problems are reported.

关键词： nonlinear Lagrange algorithm general nonlinear constrained optimization problem solutionmapping multiplier mapping condition number.

COMPARISON BETWEEN BOUSSINESQ EQUATIONS AND MILD-SLOPE EQUATIONS MODEL

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Journal of Hydrodynamics 2006年第1期18卷 40-47页

作者： LI Rui-jie ZHANG su-xiang ZHANG Yang Research Institute of Physical Oceanography Hohai University Nanjing 210098 China Research Institute of Physical Oceanography Hohai University Nanjing 210098 China Department of Civil and Coastal Engineering University of Florida USA

In this paper, the Poussinesq equations and mild-slope equation of wave transformation in near-shore shallow water were introduced and the characteristics of the two forms of equations were compared and analyzed. Meanwhile, a Boussinesq wave model which includes effects of bottom friction, wave breaking and subgrid turbulent mixing is established, slot technique dealing with moving boundary and damping layer dealing with absorbing boundary were estab lished. By adopting empirical nonlinear dispersion relation and including nonlinear term, the mild-slope equation model was modified to take nonlinear effects into account. The two types of models were validated with the experiment results given by Berkhoff and their accuracy was analysed and compared with that of correlated methods.

关键词： Boussinesq equations mild-slope equation,wave transformation correlative analysis

An Augmented Lagrangian based Semismooth Newton Method for a Class of Bilinear Programming Problems

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Applied Mathematics(A Journal of Chinese Universities) 2019年第4期34卷 446-459页

作者： HE su-xiang LIU Yan WANG Chuan-mei School of Science Wuhan University of Technology

This paper proposes a semismooth Newton method for a class of bilinear programming problems(BLPs)based on the augmented Lagrangian,in which the BLPs are reformulated as a system of nonlinear equations with original variables and Lagrange *** strict complementarity,the convergence of the method is studied by means of theories of semismooth analysis under the linear independence constraint qualification and strong second order sufficient *** last,numerical results are reported to show the performance of the proposed method.

关键词： semismooth Newton method constrained bilinear programming problems augmented Lagrangian strict complementarity

Separation and recovery of rare earth from waste nickel-metal hydride batteries by phosphate based extraction-precipitation

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Journal of Rare Earths 2022年第6期40卷 974-980,I0005页

作者： Hailan Zhi Shuainan Ni xiang su Wenqi Xie Hepeng Zhang Xiaoqi sun College of Chemistry and Materials Science Fujian Normal UniversityFuzhou 350007China Fujian CAS Key Laboratory of Design and Assembly of Functional Nanostructures and Fujian Key Laboratory of NanomaterialsFujian Institute of Research on the Structure of MatterChinese Academy of SciencesFuzhou 350002China Fujian Research Center for RE Engineering Technology Xiamen Institute of RE MaterialsHaixi InstituteChinese Academy of SciencesXiamen 36102JChina Jiangxi Province Key Laboratory of Cleaner Production of Rare Earths Ganjiang Innovation AcademyChinese Academy of SciencesGanzhou 341000China Ganzhou Rare Earth Group Co. Ltd.China Southern Rare EarthGanzhou 341000China

A novel type of extraction-precipitation strategy based on phosphate was developed to recover rare earth(RE,i.e.,La,Ce,Nd,and Pr)from waste nickel-metal hydride(NiMH)*** method does not require saponification and organic *** novel phosphates,i.e.,dibenzyl phosphate(DBP),diphenyl phosphate(DPP),triphenyl phosphate(TPP)were studied as *** has high precipitation efficiencies for RE^(3+),which can reach 97.84%,100%,100%and 99.77%,*** addition,the precipitation efficiencies of Mn^(2+),Co^(2+)and Ni^(2+)are less than 1.75%.DBP-RE has the largest particle size(D10=52.6μm,D50=135.35μm,D90=296.08μm),which is much larger than the precipitations formed by NH_(4)HCO_(3),H_(2)C2O_(4),CaO and *** larger precipitation particle sizes contribute to improving the solid-liquid separation *** 3 mol/L hydrochloric acid,the stripping efficiency of DBP-RE reaches 98.60%,and the purity of recovered RE is 99.85%.The regenerated DBP can be directly used for the recycling ***,the novel extraction-precipitation strategy is a green and sustainable separation method.

关键词： Waste nickel-metal hydride battery Rare earth Extraction-precipitation Phosphonic acid(ester)

Precipitating thermally reinforcement phase in aluminum alloys for enhanced strength at 400℃

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Journal of Materials Science & Technology 2024年第5期172卷 71-82页

作者： xiang su Yuan Lei Yang Chen Hongjie Qu Zhixiang Qi Gong Zheng Xu Liu Henggao xiang Guang Chen National Key Laboratory of Advanced Casting Technologies MIIT Key Laboratory of Advanced Metallic and Intermetallic Materials TechnologyEngineering Research Center of Materials Behavior and DesignMinistry of EducationNanjing University of Science and TechnologyNanjing 210094China School of Aviation and Mechanical Engineering Changzhou Institute of TechnologyChangzhou 213032China

Heat-resistant aluminum alloys are widely used in aerospace and automotive fields for manufacturing hot components due to their advantages in lightweight design and energy ***,the high-temperature strength of existing cast aluminum alloys is always limited to about 100 MPa at 350℃due to coarsening and transformation of strengthening ***,we reveal that the yield strength and ultimate tensile strength of the T6 state Al-8.4Cu-2.3Ce-1.0Mn-0.5Ni-0.2Zr alloy at 400◦C increase by 34%and 44%after re-aging at 300℃for 100 h,and its thermal strength exhibits distinguished ad-vantage over traditional heat-resistant aluminum *** enhanced elevated-temperature strength is attributed to the reprecipitation of the Ni-bearing T-Al_(20)Cu_(2)Mn_(3)phase,whose number density increases over one *** significant segregation of Ni,Ce,and Zr elements at the interfaces helps improve the thermal stability of the T *** thermostable T phase effectively strengthens the matrix by in-hibiting dislocation ***,a highly interconnected 3D intermetallic network along the grain boundaries can still remain after long-term re-aging at 300℃,which is conducive to imposing a drag on the grain boundaries at high *** finding offers a viable route for enhancing the elevated-temperature strength of heat-resistant aluminum alloys,which could provide expanded opportunities for higher-temperature applications.

关键词： Aluminum alloys Precipitation Thermally reinforcement phase Re-aging treatment High-temperature strength

Effect of cold rolling and annealing on microstructure and properties of a new resource-saving duplex stainless steel Fe–19Cr–0.6Al–12Mn

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Journal of Iron and Steel Research International 2020年第12期27卷 1420-1432页

作者： Ming-ming Pan Xiao-ming Zhang Yong Chen xiang-bin su Peng Chen State Key Laboratory of Rolling and Automation Northeastern UniversityShenyang 110819LiaoningChina

An Fe-19Cr-0.6Al-12Mn duplex stainless steel with an optimized alloy composition of Ni replaced by Mn and Cr partially replaced by Al was developed to avoid the edge cracking, which is a common defect in the hot rolling of traditional twophase stainless steels. The newly developed duplex stainless steel could be hot-rolled in the single-phase ferrite (α) region by controlling rolling temperature and the single-phase ferrite microstructure was retained on water cooling. To obtain the two-phase stainless steel product with ferrite and austenite (γ) microstructure, cold rolling and annealing were carried out,and appropriate cold rolling reduction and annealing process parameters were determined. The significant impact of annealing on microstructure, mechanical properties and pitting resistance of the experimental steel was studied. It was observed that with the increase in cold rolling reduction, the number of γ nucleation points was dramatically increased leading to the precipitation of more γ at α grain boundaries after annealing. During annealing at 800 ℃ and with the increase in annealing time, the austenite fraction was increased with a lower rate and remained almost constant when the annealing time was greater than 4 h. With the increase in annealing temperature, the austenite fraction decreased gradually in the temperature range of 750-860 ℃. Good combination of strength, ductility and excellent pitting resistance was obtained by cold rolling to 80% reduction and annealing at 800 ℃ for 4 h. Grain refinement and the existence of Σ3 boundaries played a vital role in improving the pitting resistance of the experimental steel. With good combination of strength, ductility and corrosion resistance, the newly developed duplex stainless steel is expected to be a new resource-saving dual-phase stainless steel.

关键词： Resource-saving duplex stainless steel Edge cracking Rolling reduction Annealing Tensile property Pitting corrosion

Dielectric Spectroscopy Study on Vesicles of CTAB/SDBS System

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Chinese Chemical Letters 2001年第1期12卷 91-94页

作者： su xiang WEI Ying LI Kong Shuang ZHAO Department of Chemistry South China Normal UniversityGuangzhou 510631

Amphiphilic molecules can form into different structures, such as micelle, microemulsion, vesicle, liposome, liquid crystals, and so on by self-associating. The Dielectric Spectroscopy (DS) method has been applied to the systems of micelle and microemulsion successfully. For the first time the author put the method to the system of vesicle of CTAB/SDBS. The experiments show clear dielectric relaxation and the results were discussed primarily.

关键词： Dielectric spectroscopy vesicle macroscopic relaxation time