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Multi-dimensional Backward Stochastic Differential Equations of Diagonally Quadratic Generators with a Special Structure

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Chinese Annals of Mathematics,Series B 2024年第6期45卷 855-868页

作者： guang yang Shanghai Center for Mathematical Sciences Fudan University

The present paper is devoted to the well-posedness of a type of multi-dimensional backward stochastic differential equations（BSDE for short） with a diagonally quadratic generator. The author gives a new priori estimate, and prove that the BSDE admits a unique solution on a given interval when the generator has a sufficiently small growth of the off-diagonal elements（i.e., for each i, the i-th component of the generator has a small growth of the j-th row zjof the variable z for each j ≠ i）. Finally, a solvability result is given when the diagonally quadratic generator is triangular.

关键词： 60H10 BMO martingale Diagonally quadratic generator Multi-dimensional BSDE

Blockage robust millimeter-wave networks

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Science China(Information Sciences) 2017年第8期60卷 77-79页

作者： guang yang Ming XIAO KTH Royal Institute of Technology

Millimeter-wave(mm Wave)technique(from around 24 GHz to 300 GHz)becomes a key enabler of high date rates for future mobile communications[1].In spite of many appealing benefits,mm Wave communications also encounter several critical challenges,i.e.,very weak capability in penetration,diffraction and high-order reflections,due to the short wavelength[2].That indicates,the transmission in mm Wave bands can be blocked easily if any obstacle,e.g.,human body or vehicle in motion,occurs on the propagation path.

关键词： Wave work in AP of as link TDMA Blockage robust millimeter-wave networks is or MBS MAC wave that

An Interior-Point Algorithm for Linear Programming with Optimal Selection of Centering Parameter and Step Size

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Journal of the Operations Research Society of China 2021年第3期9卷 659-671页

作者： Ya-guang yang Nuclear Regulatory Commission Office of ResearchRockville 20850USA

For interior-point algorithms in linear programming,it is well known that the selection of the centering parameter is crucial for proving polynomiality in theory and for efficiency in ***,the selection of the centering parameter is usually by heuristics and separated from the selection of the line-search step *** heuristics are quite different while developing practically efficient algorithms,such as Mehrotra’s predictor–corrector(MPC)algorithm,and theoretically efficient algorithms,such as short-step path-following *** introduces a dilemma that some algorithms with the best-known polynomial bound are least efficient in practice,and some most efficient algorithms may not be convergent in polynomial ***,in this paper,we propose a systematic way to optimally select the centering parameter and linesearch step size at the same time,and we show that the algorithm based on this strategy has the best-known polynomial bound and may be very efficient in computation for real problems.

关键词： Interior-point method Convergence Polynomial algorithm Linear programming

A sol-gel transition induced by dilution

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Science China Chemistry 2022年第9期65卷 1681-1682页

作者： guang yang Guosong Chen Biomass Molecular Engineering Center Anhui Agricultural UniversityHefei 230036China Department of Macromolecular Sciences Fudan UniversityShanghai 200433China

Shaped by multiple noncovalent interactions,the interwoven fibrous network consisting of several components(collagen,laminin and proteoglycans etc.)is a unique feature reserved by the natural extracellular matrix(ECM).Recently,great attention of scientists has been aroused to mimic ECM through constructing the synthetic supramolecular systems[1,2].

关键词： constructing matrix fibrous

Numerical Simulation of Heat and Momentum Transport at the Coupled Interface between a Rectangular Channel and Porous Media

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Journal of Thermal Science 2022年第2期31卷 332-343页

作者： WANG Ye WU Jingyi yang guang Institute of Refrigeration and Cryogenics Shanghai Jiao Tong UniversityShanghai 200240China

Porous media have been extensively used for the enhancement of heat transfer,due to their large specific surface *** many cases,the flow and heat transfer in porous media are also coupled with other flow patterns,such as the channel *** work investigates numerically a non-isothermal three-dimensional mixing process from a rectangular channel and a porous medium to reveal the influence of the structural parameters on the flow and heat transfer characteristics in the coupled *** detailed heat and momentum transport behavior at the coupled interface are analyzed at the *** of the friction factor and the Nusselt number within the porous media are proposed as functions of the Reynolds number,porosity,velocity ratio,and pore *** from the pore-scale simulations are also used to improve the less-cost representative-elementary-volume-scale numerical model,which can be further used for the modeling of relevant engineering problems.

关键词： porous media cross-flow pore-scale simulation structural effect convective heat transfer

Vertical Diffusion Coefficient with Stratification Effect for Silty Sediment Suspension Under Waves

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China Ocean Engineering 2023年第2期37卷 323-332页

作者： yang guang-yao ZHANG Qing-he State Key Laboratory of Hydraulic Engineering Simulation and Safety Tianjin UniversityTianjin 300072China

To analyze previous experimental data of suspended sediment concentration for silty sediment with different sediment particle sizes due to waves, a new stratification correction coefficient is presented. The suspended sediment concentration gradient and sediment particle diameter are selected as parameters. Furthermore, a diffusion coefficient model with a stratification effect over the whole water depth for silty sediment suspension under waves is developed. The comparison between the suspended sediment concentration calculated by the presented model and several groups of experimental data shows that the model can reasonably reflect the vertical distribution of silty sediment *** stratification effect calculated by the present model decreases with an increase in the sediment particle diameter,which indicates that the model can be extended to describe the suspended sediment concentration of fine to medium sand when the near-bottom sediment concentration is not very high. Although the original model needs to be iteratively solved, the approximate method without iteration is recommended for applications when the near bottom sediment concentration is between 10 and 20 kg/m~3 due to the small difference between the non-iterative and iterative solution for near bed layer suspended sediment concentration, which plays a major role in sediment transport.

关键词： stratification silty sediment suspension diffusion coefficient wave

Conduction-convection coupled heat transfer around a hollow cylinder under different buoyancy forces

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Chinese Journal of Aeronautics 2024年第4期37卷 216-228页

作者： Wanyu ZHANG Jingyi WU guang yang Institute of Refrigeration and Cryogenics Shanghai Jiao Tong UniversityShanghai 200240China

In order to clarify the effect of a buoyancy force on conduction–convection coupled heat transfer in a hollow cylinder, the flow and thermal characteristics were analyzed using an RNG k-ε turbulence model. The Reynolds number was fixed at 1.014 × 10^(6), and the Rayleigh number varied from 1.122 × 10^(10)to 1.088 × 10^(11). Results have shown that, when considering the effect of an opposed buoyancy force, increasing the Rayleigh number has a positive impact on the rate of change and uniformity of the cylinder temperature. The temperature distributions along the axial and circumferential directions are similar for different Rayleigh numbers, but extreme values *** the axial direction, the maximum temperature is obtained at the interface between the variable-diameter part and the constant-diameter part. The maximum dimensionless temperature value decreases to 0.12 when the Rayleigh number increases to 1.088 × 10^(11). Along the circumferential direction, the temperature distribution is affected by the buoyancy force, which results in the temperature of the upper part being higher than that of the lower part. After nondimensionalization of the temperature and time, a correlation was proposed to illustrate the transient heat transfer process quantitatively. The standard deviation of the maximum relative temperature, representing the temperature uniformity, was also calculated. It was found that the difference in the direction of the buoyancy force made a huge difference. Compared with the opposed buoyancy force, the maximum dimensionless temperature is almost two times higher with an assisted buoyancy force. Similarly, the heat transfer coefficient with an assisted buoyancy force is half of that with an opposed buoyancy force. Overall, an assisted buoyancy force plays a negative role in terms of thermal characteristics. The flow field around the hollow cylinder was also illustrated to reveal the mechanism of the buoyancy force on magnitude and direction aspects

关键词： Buoyancy Conduction-convection heat transfer Transient analysis Hollow cylinder Non-dimensionalization

Halide ion-induced formation of single crystalline mesoporous PtPd bimetallic nanoparticles with hollow interiors for electrochemical methanol and ethanol oxidation reaction

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Nano Research 2017年第3期10卷 1064-1077页

作者： Pengtao Qiu Shaomin Lian guang yang Shengchun yang School of Science Key Laboratory of Shaanxi for Advanced Materials and Mesoscopic Physics State Key Laboratory for Mechanical Behavior of Materials Xi'an 2iaotong University Xi'an 710049 China Electronic Materials Research Laboratory Key Laboratory of the Ministry of Education & International Center for Dielectric Research Xi' an Jiaotong University Xi'an 710049 China Collaborative Innovation Center of Suzhou Nano Science and Technology Suzhou Academy of Xi'an Jiaotong University Suzhou 215000 China

We demonstrate a facile hydrothermal one-pot synthesis method for producing single crystalline mesoporous PtPd bimetallic nanoparticles with a hollow interior and porous surface structure in the presence of Br- and F ions. The formation process analysis indicated that the coexistence of Br- and I- ions is responsible for the formation of the novel bimetallic nanoparticles. The changes in the reduction potential of Pt and Pd metal ions achieved by the coordination with different halide ions resulted in the formation of hollow interiors as a galvanic reaction between Pd2~ and Pt4. ions occurred. In addition, the size of the mesoporous PtPd nanoparticles can be well controlled by slightly changing the amount of I- ions used. The electrochemical tests indicated that the as- synthesized single crystalline mesoporous PtPd hollow nanoparticles exhibited enhanced catalytic properties toward methanol and ethanol oxidation reactions as compared with the commercial Pt black and Pt/C materials.

关键词： noble metalmesoporous single crystal hollow interior electrocatalysis

An improvement to the reciprocating gait orthosis for aiding paraplegic patients in walking

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Science China(Technological Sciences) 2015年第4期58卷 727-737页

作者： CHEN Dian Sheng NING Meng ZHANG Ben guang yang guang Robotic Institute Beihang University

As the conventional reciprocating gait orthosis(RGO)has been deemed incapable of facilitating the patients’passive movement with significant gait discrepancies and distortion,in addition to characteristics such as poor stability,and negligible knee joint rehabilitation,a power assisted reciprocating gait orthosis(PARGO)was *** devices were added to the hip and knee joints of the *** efficient implementation of structural components,the number of the required motors was reduced,therefore decreasing the weight of the *** PARGO knee joint’s structural principle was analyzed to characterize the effect of the PARGO’s single-axis knee joint design on wear comfort,thereby providing a basis for the wear of the *** analyzing the sagittal movement patterns of the hip and knee joints during normal human gait,kinematic analysis was carried out to obtain the input patterns of the PARGO hip and knee joint drive motors,enabling the patients to more accurately reproduce the normal gaits of hip and knee joints during the rehabilitation training with the aid of the PARGO,and the control process of the PARGO was ***,a prototype of the PARGO was developed,and experimentation was carried out to demonstrate the feasibility of the improved orthosis.

关键词： reciprocating gait orthosis kinematics analysis stability study position control experimental validation