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Chinese Physics B 2016年第12期25卷 144-152页

作者：乔要宾齐宏赵方舟阮立明 School of Energy Science and Engineering Harbin Institute of Technology

Reconstructing the distribution of optical parameters in the participating medium based on the frequency-domain radiative transfer equation （FD-RTE） to probe the internal structure of the medium is investigated in the present work. The forward model of FD-RTE is solved via the finite volume method （FVM）. The regularization term formatted by the generalized Gaussian Markov random field model is used in the objective function to overcome the ill-posed nature of the inverse problem. The multi-start conjugate gradient （MCG） method is employed to search the minimum of the objective function and increase the efficiency of convergence. A modified adjoint differentiation technique using the collimated radiative intensity is developed to calculate the gradient of the objective function with respect to the optical parameters. All simulation results show that the proposed reconstruction algorithm based on FD-RTE can obtain the accurate distributions of absorption and scattering coefficients. The reconstructed images of the scattering coefficient have less errors than those of the absorption coefficient, which indicates the former are more suitable to probing the inner structure.

关键词： inverse problem adjoint differentiation multi-start conjugate gradient method frequency-domainradiative transfer equation

A seventh-order model for dynamic response of an electro-hydraulic servo valve

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Chinese Journal of Aeronautics 2014年第6期27卷 1605-1611页

作者： Liu Changhai Jiang Hongzhou Department of Fluid Control and Automation Harbin Institute of Technology

In this paper, taking two degrees of freedom on the armature–flapper assembly into account, a seventh-order model is deduced and proposed for the dynamic response of a two-stage electro-hydraulic servo valve from nonlinear equations. These deductions are based on fundamental laws of electromagnetism, fluid, and general mechanics. The coefficients of the proposed seventhorder model are derived in terms of servo valve physical parameters and fluid properties *** validating the results of the proposed model, an AMESim simulation model based on physical laws and the existing low-order models validated by other researchers through experiments are used to compare with the seventh-order model. The results show that the seventh-order model can reflect the physical behavior of the servo valve more explicitly than the existing low-order models and it could provide guidance more easily for a linear control design approach and sensitivity analysis than the AMESim simulation model.

关键词： Hydraulic control systems Nozzle–flapper Servo valve Torque motor Transfer function

High activity in catalytic cracking of large molecules over micro-mesoporous silicoaluminophosphate with controlled morphology

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Science China Chemistry 2010年第11期53卷 2279-2284页

作者： QI Jian ZHAO TianBo XU Xin LI FengYan SUN GuiDa institute for Chemical Physics Beijing Institute of TechnologyBeijing 100081China Department of Applied Chemistry Beijing Institute of Petrochemical TechnologyBeijing 102617China

A novel micro-mesoporous silicoaluminophosphate(MUS-5) with controlled morphology has been first synthesized in a two-step *** physical properties of the silicoaluminophosphate were characterized using XRD,SEM,TEM,nitrogen adsorption-desorption and NH3-TPD *** the pH value of the solution system was varied in the range from 2.0 to 5.0,three different morphologies of silicoaluminophosphate including chain-like,flower-like and barrel-like morphology were *** tests showed that the silicoaluminophosphate exhibited higher catalytic activity compared with the conventional microporous SAPO-5 under the same conditions for catalytic cracking of 1,3,5-triisopropylbenzene heavy *** remarkable catalytic reactivity was mainly attributed to the presence of the hierarchical porosity in the silicoaluminophosphate catalyst.

关键词： micro-mesoporous silicoaluminophosphate controlled morphology catalytic cracking large molecule

The binocular neural mechanism: disparity coding schemes and population coding

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Science China(Information Sciences) 2015年第9期58卷 69-82页

作者： ZHAO Li Information Engineering institute Henan University of Science and Technology

Stereoacuity thresholds measured on disparity pedestals are generally found to increase exponentially as the pedestals move away from horopters. However, Farell et al. recently found that for sinusoidal stimuli this threshold function had a dip—a pedestal effect. This paper examines the underlying neural *** suggest a general disparity coding scheme with two position parameters, which are necessary to account for the phenomenon that the response of the energy model depends on the absolute phase of the stimulus. This scheme was implemented to simulate the responses, calculated from an energy model, of the neurons of a full V1 cortical column. To explain the stereo pedestal effect, we propose a decoding mechanism, which is first processed along the phase dimension and then along the orientation dimension. The final step of the decoding mechanism, probability summation over the outputs of spatial frequency channels, yields the dip, producing a disparity increment threshold function similar to the psychophysical result.

关键词： stereopsis disparity discrimination disparity coding increment thresholds neural integration

Phase-field simulation of dendritic growth for binary alloys with complicate solution models

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中国有色金属学会会刊：英文版 2005年第4期15卷 769-776页

作者：李新中郭景杰苏彦庆吴士平傅恒志 School of Materials Science and Engineering Harbin Institute of Technology

A phase-field method for simulation of dendritic growth in binary alloys with complicate solution models was studied. The free energy densities of solid and liquid used to construct the free energy of a solidification system in the phase-field model were derived from the Calphad thermodynamic modeling of phase diagram. The dendritic growth of Ti-Al alloy with a quasi-sub regular solution model was simulated in both an isothermal and a non-isothermal regime. In the isothermal one, different initial solute compositions and melt temperatures were chosen. And in the non-isothermal one, release of latent heat during solidification was considered. Realistic growth patterns of dendrite are derived. Both the initial compositions and melt temperatures affect isothermal dendritic morphology and solute distributions much, especially the latter. Release of latent heat will cause a less developed structure of dendrite and a lower interfacial composition.

关键词：合金铸造工艺浇注工艺金属加工

Synthesis and Characterization of Fe_(50)Cr_(14)Mo_(14)C_(14)B_6Gd_2 Bulk Amorphous Steel

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Journal of Materials Science & technology 2010年第9期26卷 783-786页

作者： M. Iqbal J.I. Akhter H.F. Zhang Z.Q. Hu Physics Division Pakistan Institute of Nuclear Science &: Technology P.O. Nilore Islamabad Pakistan Shenyang national Laboratory for Materials Science Institute of Metal Research Chinese Academy of SciencesShenyang 110016 China

Bulk amorphous steel having 7 mm thickness was synthesized to evaluate its thermal stability and mechanical *** steel was synthesized by Cu mold casting technique using 1-2N pure *** of the material was done by X-ray diffraction,differential scanning calorimetry and scanning electron *** activation energies were calculated by Kissinger equation and it was found that the steel had better stability against *** properties like Vicker s hardness,nanohardness,elastic modulus and elastic recovery of as-cast and annealed samples were *** was concluded that the present steel had good glass-forming ability（GFA） and mechanical properties.

关键词： Bulk amorphous steels Activation energy Glass-forming ability Mechanical properties

Entropy squeezing for a two-level atom in two-mode Raman coupled model with intrinsic decoherence

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Chinese Physics B 2009年第4期18卷 1517-1527页

作者：张剑邵彬邹健 Department of Physics School of Science Beijing Institute of Technology

In this paper, we investigate the entropy squeezing for a two-level atom interacting with two quantized fields through Raman coupling. We obtain the dynamical evolution of the total system under the influence of intrinsic decoherence when the two quantized fields are prepared in a two-mode squeezing vacuum state initially. The effects of the field squeezing factor, the two-level atomic transition frequency, the second field frequency and the intrinsic decoherence on the entropy squeezing are discussed. Without intrinsic decoherence, the increase of field squeezing factor can break the entropy squeezing. The two-level atomic transition frequency changes only the period of oscillation but not the strength of entropy squeezing. The influence of the second field frequency is complicated. With the intrinsic decoherence taken into consideration, the results show that the stronger the intrinsic decoherence is, the more quickly the entropy squeezing will disappear. The increase of the atomic transition frequency can hasten the disappearance of entropy squeezing.

关键词： entropy squeezing intrinsic decoherence two-mode Raman coupled model

Generating Time-Series Data Using Generative Adversarial Networks for Mobility Demand Prediction

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Computers, Materials & Continua 2023年第3期74卷 5507-5525页

作者： Subhajit Chatterjee Yung-Cheol Byun Department of Computer Engineering Jeju National UniversityJeju-si63243Korea Department of Computer Engineering Major of Electronic EngineeringJeju National UniversityInstitute of Information Science&TechnologyJeju63243Korea

The increasing penetration rate of electric kickboard vehicles has been popularized and promoted primarily because of its clean and efficient *** kickboards are gradually growing in popularity in tourist and education-centric *** the upcoming arrival of electric kickboard vehicles,deploying a customer rental service is *** to its freefloating nature,the shared electric kickboard is a common and practical means of *** plans for shared electric kickboards are required to increase the quality of service,and forecasting demand for their use in a specific region is *** demand accurately with small data is *** data is necessary for training machine learning algorithms for effective *** generation is a method for expanding the amount of data that will be further accessible for *** this work,we proposed a model that takes time-series customers’electric kickboard demand data as input,pre-processes it,and generates synthetic data according to the original data distribution using generative adversarial networks(GAN).The electric kickboard mobility demand prediction error was reduced when we combined synthetic data with the original *** proposed Tabular-GAN-Modified-WGAN-GP for generating synthetic data for better prediction *** modified The Wasserstein GAN-gradient penalty(GP)with the RMSprop optimizer and then employed Spectral Normalization(SN)to improve training stability and faster ***,we applied a regression-based blending ensemble technique that can help us to improve performance of demand *** used various evaluation criteria and visual representations to compare our proposed model’s *** data generated by our suggested GAN model is also *** TGAN-Modified-WGAN-GP model mitigates the overfitting and mode collapse problem,and it also converges faster than previous GAN models for synthetic data creation.

关键词： Machine learning generative adversarial networks electric vehicle time-series TGAN WGAN-GP blend model demand prediction regression

Density-functional study of CO adsorbed on Rh_N (N=2-19) clusters

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Chinese Physics B 2011年第12期20卷 192-199页

作者：田付阳申江 institute for Applied Physics University of Science and Technology Beijing

We investigate the structural, electronic and adsorption properties of one single CO molecule adsorbed on RhN （N = 2-19） clusters, using the density-functional theory in the spin-polarized generalized gradient approximation. It is found that the structural growth model of the RhN clusters transforms from double layers （N = 12-16） to three layers （N ： 17-19）. Three different adsorption types are the atop site adsorption for N = 6, 8, 9, 11, 12, the bridge site adsorption for N ： 2-5, 7, 10, 13-15, 17 and the face adsorption for N = 16, 18, 19. The adsorption abilities of RhN clusters are related to C-O bond length, vibrational frequency, adsorption energy and the charge transfer between CO and Rh clusters as well as the electronic density of state. With the increase of Rh cluster size, the adsorption energy of CO adsorbed on RhN clusters tends to be 2.2 eV-2.3 eV, which is 0.2 eV-0.3 eV larger than the theoretical value （about 2.0 eV） of CO molecule adsorption on clean Rh （111） surface.

关键词： CO-RhN compounds adsorption energy vibrational frequency electronic density ofstate

Rayleigh-type wave propagation through liquid layer over corrugated substrate

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Applied Mathematics and Mechanics(English Edition) 2017年第6期38卷 851-866页

作者： A.K.SINGH A.DAS A.RAY Department of Applied Mathematics Indian Institute of Technology(ISM)

The propagation of the Rayleigh-type wave in a fluid layer overlying a corrugated substrate is studied. The corrugated substrate is considered as a fluid satu- rated poroelastic substrate and a quadratically heterogeneous isotropic elastic substrate in Case I and Case II, respectively. Closed form expressions of dispersion relation for Case I and Case II ave obtained. The influence of corrugation, porosity, and hetero- geneity on the phase velocity of Rayleigh-type wave, for both cases, is highlighted and demonstrated through numerical computation and graphical discussion. Neglecting cor- rugation at the common interface, expressions of phase velocity of the Rayleigh-type wave for both cases ave derived in a closed form as a special case of the problem. Comparison between the presence and the absence of both heterogeneity and poroelasticity in the substrate of the composite structure is a key in the present study.

关键词： Rayleigh-type wave porosity heterogeneity corrugation