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General semi-analytical solutions to one-dimensional consolidation for unsaturated soils

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Applied Mathematics and Mechanics(English Edition) 2017年第6期38卷 831-850页

作者： Lei WANG De'an sun Aifang QIN Department of Civil Engineering Shanghai University

This paper presents general semi-analytical solutions to Fredlund and Hasan＇s one-dimensional （1D） consolidation equations for unsaturated soils subject to different initial conditions, homogeneous boundaries and time-dependent loadings. Two variables are introduced to transform the two-coupled governing equations of pore-water and poreair pressures into an equivalent set of partial differential equations （PDEs）, which are solved with the Laplace transform method. The pore-water and pore-air pressures and settlement are obtained in the Laplace transform domMn. The Crump＇s method is used to perform inverse Laplace transform to obtain the solutions in the time domain. The present solutions are more general in practical applications and show good agreement with the previous solutions in the literature.

关键词： semi-analytical solution unsaturated soil one-dimensional consolidation,homogeneous boundary condition time-dependent loading

FBFN-based adaptive repetitive control of nonlinearly parameterized systems

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Journal of Systems Engineering and Electronics 2013年第6期24卷 1003-1010页

作者： Wenli sun Hong Cai Fu Zhao School of Aerospace Science and Engineering National University of Defense Technology Beijing Aerospace Control Device Institute

An adaptive repetitive control scheme is presented for a class of nonlinearly parameterized systems based on the fuzzy basis function network （FBFN）. The parameters of the fuzzy rules are tuned with adaptive schemes. To attenuate chattering effectively, the discontinuous control term is approximated by an adaptive PI control structure. The bound of the discontinuous control term is assumed to be unknown and estimated by an adaptive mechanism. Based on the Lyapunov stability theory, an adaptive repetitive control law is proposed to guarantee the closed-loop stability and the tracking performance. By means of FBFNs, which avoid the nonlinear parameterization from entering into the adaptive repetitive control, the controller singularity problem is solved. The proposed approach does not require an exact structure of the system dynamics, and the proposed controller is utilized to control a model of permanent-magnet linear synchronous motor subject to significant disturbances and parameter uncertainties. The simulation results demonstrate the effectiveness of the proposed method.

关键词： adaptive control nonlinear parameterization repetitive control fuzzy basis function network (FBFN) permanentmagnet linear synchronous motor (PMLSM)

HyBar:high efficient barrier synchronization based on a hybrid packet-circuit switching Network-on-Chip

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Science China(Information Sciences) 2017年第6期60卷 237-248页

作者： Zhenqi WEI Peilin LIU Rongdi sun School of Electronic Information and Electrical Engineering Shanghai Jiao Tong University

Realizing barrier synchronization in multi-/many-core processors with high efficiency becomes more and more challenging as the number of cores integrated in a single chip keeps growing. Quite a few barrier solutions have been proposed, while they provide limited improvements for synchronizing large amounts of cores or incur unfavorable restrictions on performing concurrent barriers. This paper presents Hy Bar, a hardware barrier based on a hybrid switching No C which adopts packet switching and circuit switching methods in two sub-networks respectively. Dedicated channels in the circuit-switching sub-network are dynamically built and removed when barrier requests traverse the packet-switching sub-network according to a modified dimensionorder routing algorithm. The efficiency of inter-core communication for concurrent barriers is improved by merging barrier arrival requests and broadcasting release requests along the circuit channels. The execution time of synthetic cases, benchmark kernels and parallel applications using various barrier solutions are evaluated in an RTL-based simulation platform. Experimental results show that our proposal provides about 15%–50%performance improvement compared to previous solutions, while the hardware overhead is marginal under SMIC40 nm technology. Moreover, Hy Bar introduces a minor efficiency loss for concurrent barriers with no limitation on their layouts of participating cores in the on-chip network.

关键词： NoC barrier synchronization packet-circuit switching concurrent barriers routing algorithm

Hydrodynamics characterization of a choanoid fluidized bed bioreactor used in the bioartificial liver system： Fully resolved simulation with a fctitious domain method

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Particuology 2017年第3期15卷 39-48页

作者： Jingyuan sun Zhaosheng Yu Shangjun Ye Department of Mechanics State Key Laboratory of Fluid Power and Mechatronic Systems Zhejiang University Hangzhou 310027 China

Choanoid fluidized bed bioreactors （CFBBs） are newly developed core devices used in bioartificial liver- support systems to detoxify blood plasma of patients with microencapsulated liver cells. Direct numerical simulations （DNS） with a direct-forcing/fictitious domain （DF/FD） method were conducted to study the hydrodynamic performance of a CFBB. The effects of particle-fluid density ratio, particle number, and fil- ter screens preventing particles flowing out of the reactor were investigated. Depending on density ratio, two flow patterns are evident： the circulation mode in which the suspension rises along one sidewall and descends along the other sidewall, and the non-circulation mode in which the whole suspension roughly flows upward. The circulation mode takes place under non-neutral-buoyancy where the particle sedimentation dominates, whereas the non-circulation mode occurs under pure or near-neutral buoy- ancy with particle-fluid density ratios of unity or near unity. With particle-fluid density ratio of 1.01, the bioartificial liver reactor performs optimally as the significant particle accumulation existing in the non-circulation mode and the large shear forces on particles in the circulation mode are avoided. At higher particle volume fractions, more particles accumulate at the filter screens and a secondary counter circulation to the primary flow is observed at the top of the bed. Modelled as porous media, the filter screens play a negative role on particle fluidization velocities; without screens, particles are fluidized faster because of the higher fluid velocities in the jet center region. This work extends the DF/FD-based DNS to a fluidized bed and accounts for effects from inclined side walls and porous media, providing some hydrodynamics insight that is important for CFBB design and operation optimization.

关键词： Choanoid fluidized-bed bioreactor Particle-laden flows Direct numerical simulation Direct-forcing/fctitious domain method Hydrodynamic characteristics

Metabolism Kinetics of Glucose in Anchorage-dependent Cell Cultures

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过程工程学报 2001年第4期1卷 387-393页

作者：孙祥明张元兴华东理工大学生物反应器工程国家重点实验室上海 200237

The kinetic model of glucose metabolism was established and successfully applied to batch cultures of rCHO and rBHK cells. It was found that a large amount of glucose was utilized for cell maintenance, and the overwhelming majority of maintenance energy from glucose was by its anaerobic metabolism in both rBHK and rCHO cell cultures. The overall maintenance coefficients from aerobic metabolism were 1.910-13 mmol/(cell穐) for rCHO cells and 710-13 mmol/(cell穐) for rBHK cells. In addition, all GO/T and EO/T gradually increased with the same trend as the cell growth in the culture of both rCHO and rBHK cells. The overall molecule yield coefficients of lactate to glucose were 1.61 for rCHO cells and 1.38 for rBHK cells. The yield coefficients of cell to glucose were 4.5108 cells/mmol for rCHO cells and 1.9 108 cells/mmol for rBHK cells, respectively.

关键词：动物细胞细胞培养新陈代谢动力学葡萄糖

Dynamic modeling and simulation of a pressurized system used in flight vehicle

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Chinese Journal of Aeronautics 2018年第6期31卷 1232-1248页

作者： Bing sun Qi XU Yang CHEN School of Astronautics Beihang University

For a typical pressurized system with a novel dual-stage gas pressure reducing regulator,a system model is established with modular models of various typical components. The simulation study on the whole working period shows that the general trends and magnitudes of simulation curves are in agreement with experimental measured curves. As the key component in the pressurized system, the regulator is studied by a series of numerical simulations to reveal the influences of various structure parameters on its stability. Furthermore, the variable ranges which can guarantee the stability of regulator and system are obtained to provide guidance for design. The modeling and analysis approach can be applied to other systems and components.

关键词： Dual-stage gas pressure reducing regulator Dynamic characteristics Finite volume method Numerical simulation Pressurized system Stability

Comparative studies on phosphate ore flotation collectors prepared by hogwash oil from different regions

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International Journal of Mining Science and Technology 2018年第3期28卷 453-459页

作者： Yu Huimei Wang Huajun sun Chuanyao School of Civil and Resource Engineering University of Science and Technology Beijing Beijing 100083 China Key Laboratory of Metal Mine Efficient Mining and Safety Education Ministry University of Science and Technology Beijing Beijing 100083 China State Key Laboratory of Science and Technology of Mineral Processing Beijing General Research Institute of Mining and Metallurgy Beijing 100070 China

In order to compare the differences between variations of phosphate ore flotation collectors prepared by hogwash oils, JZQ-F collectors were prepared by the hydrolysis method using four types of hogwash oils from different regions in China. The components of the hogwash oils were determined using Fourier transform infrared spectroscopy(FIIR) spectra analysis, while the components of the JZQ-F were determined through gas chromatography–mass spectrometry(GC–MS). The flotation effects of the JZQ-F collectors were investigated by flotation experiments and the adsorption characteristics were determined through the quartz crystal microbalance(QCM-D). Results show that the JZQ-F collector from the Ordos area has 27.43% unsaturated fatty acids. JZQ-F collectors from Beijing, Qingdao, and Dongguan areas contain over 62% of unsaturated fatty acids, which can acquire phosphorous concentrates with a the grade of P_2O_5 above 31.96% and the recovery higher than 91.52%. These three collectors have a larger adsorption capacity, faster adsorption rate, and stronger adsorption structure on apatite surface, which contributed to a good adsorption performance and a favorable flotation effect.

关键词： Hogwash oil Flotation collector Saturated fatty acid Unsaturated fatty acid Adsorption

The sound and complete R-calculus for revising propositional theories

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Science China(Information Sciences) 2015年第9期58卷 5-16页

作者： LI Wei SUI YueFei sun MeiYing State Key Laboratory of Software Development Environment Beihang University Key Laboratory of Intelligent Information Processing Institute of Computing TechnologyChinese Academy of Sciences University of Chinese Academy of Sciences

The AGM postulates are for the belief revision(revision by a single belief), and the DP postulates for the iterated revision(revision by a finite sequence of beliefs). Li gave an R-calculus for R-configurations?|Γ,where ? is a set of atomic formulas or the negations of atomic formulas, and Γ is a finite set of formulas. In this paper, two deduction systems for the revision of a theory by another theory are given such that the systems are sound and complete, that is, if ?|Γ■Γ′ is provable then Γ′■ ? is consistent and Γ′- ? is a maximal subset of Γ such that(Γ′- ?) ∪ ? is consistent; and for any finite theories ? and Γ, there is a finite theoryΓ′ such that Γ′- ? is a maximal subset of Γ such that(Γ′- ?) ∪ ? is consistent, and ?|Γ ? Γ′ is ***, if?|Γ■Γ′ is provable then Γ′ satisfies the AGM and the DP postulates.

关键词： belief revision R-calculus minimal change the AGM postulates the DP postulates

Theoretical simulation of chromatographic separation based on random diffusion in the restricted space

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Science China Chemistry 2016年第7期59卷 824-829页

作者： Jianwei Zhao Yinlu sun Yajun Gao College of Materials and Textile Engineering Jiaxing UniversityJiaxing 314001China College of Chemistry Liaoning UniversityShenyang 110036China State Key Laboratory of Analytical Chemistry for Life Science School of Chemistry and Chemical Engineering Nanjing UniversityNanjing 210023China

The diffusion behavior of particles in the chromatography is a fundamental issue of chromatographic dynamics. The understanding of the diffusion behaviors is particularly critical to optimize the operation conditions, improve the chromatographic performance and design a new separation device. Many of the present simulations focus on chromatographic thermodynamics, and very few aim at the overall diffusion and separation process. In order to dynamically trace the trajectory of the diffusing particles and to perform simulations of the whole chromatographic process, we have developed a model based on the framework of random walk in the restricted space and performed the simulation of a single particle diffusion in the gas chromatography. The simulation parameters were determined by comparing with the experimental data. The elution profiles of n-alkanes under different flow rates were accurately simulated with the method. The results show that the relative difference between the measures and the simulations are less than 2% and 10% for the retention time and the peak width, respectively. The simulation method shows great significance for the optimization of separation conditions and the development of novel technologies of chromatographic separation.

关键词： random walk restricted space gas chromatography diffusion retention time peak width