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Efficient linear and unconditionally energy stable schemes for the modified phase field crystal equation

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Science China Mathematics 2022年第10期65卷 2201-2218页

作者： Xiaoli li Jie shen School of Mathematics Shandong UniversityJinan 250100China Department of Mathematics Purdue UniversityWest LafayetteIN 47907USA

In this paper,we construct efficient schemes based on the scalar auxiliary variable block-centered finite difference method for the modified phase field crystal equation,which is a sixth-order nonlinear damped wave *** schemes are linear,conserve mass and unconditionally dissipate a pseudo *** prove rigorously second-order error estimates in both time and space for the phase field variable in discrete *** also present some numerical experiments to verify our theoretical results and demonstrate the robustness and accuracy.

关键词： modified phase field crystal scalar auxiliary variable energy stability error estimate numerical experiments

Delay-dependent Robust Stability Analysis of Power Systems with PID Controller

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Chinese Journal of Electrical Engineering 2019年第2期5卷 79-86页

作者： li shen Huiqin Xiao School of Electrical and Information Engineering Hunan University of TechnologyZhuzhou 412007China

This study examines the robust stability of a power system,which is based on proportional-integral-derivative load frequency control and involves uncertain parameters and time *** model of the system is firstly established,following which the system is transformed into a closed-loop system with feedback *** this basis,a new augmented Lyapunov-Krasovskii(LK)functional is established for using the new Bessel-Legendre inequality to estimate the derivative of the functional,which can provide a maximum lower bound.A stability criterion is then derived by employing the LK functional and Bessel-Legendre ***,numerical examples are used to demonstrate the validity and superiority of the proposed method.

关键词： Power systems time delay systems load frequency control PID control robust stability

Numerical simulation of the impacts of water level variation on water age in Dahuofang Reservoir

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Frontiers of Earth Science 2015年第2期9卷 209-224页

作者： Xinwen li Yongming shen State Key Laboratory of Coastal and Offshore Engineering Dalian University of Technology Dalian 116023 China

The transport timescales were investigated in response to water level variation under different constant flow rates in Dahuofang Reservoir. The concept of water age was applied to quantifY the transport timescales. A three-dimensional hydrodynamic model was developed based on the Environmental Fluid Dynamics Code （EFDC）. The model was calibrated for water surface elevation and temperature profiles from April 1, 2008 to October 31, 2008. Comparisons of observed and modeled data showed that the model reproduced the water level fluctuation and thermal stratification during warm season and vertical mixing during cold season fairly well. The calibrated model was then applied to investigate the response of water age to water level changes in Dahuofang Reservoir. Model results showed that water age increases from confluence toward dam zone. In the vertical direction, the water age is relatively uniform at upstream and stratifies further downstream, with a larger value at bottom layer than at surface layer. Comparisons demonstrated that water level variation has a significant impact on transport timescales in the reservoir. The impact of water level drawdown on water age is stronger at bottom layer than at surface layer. Under high flow conditions, the water age decreases 0-20days at surface layer and 15-25 days at bottom layer. Under mean flow conditions, the water age decreases 20-30 days at surface layer and 30-50 days at bottom layer. Furthermore, the impact is minor in the upstream and increases further downstream. The vertical stratification of water age weakens as the water level decreases. This study provides a numerical tool to quantify the transport timescale in Dahuofang Reservoir and supports adaptive management of regional water resources by local authorities.

关键词： water age EFDC Dahuofang Reservoir,numerical simulation water level

On Local Spectral Properties of Hamilton Type Operators

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Acta Mathematicae Applicatae Sinica 2018年第1期34卷 173-182页

作者： Jun-li shen Alatancang College of Computer and Information Technology Henan Normal University Xinxiang 453007 China School of Mathematical Sciences Inner Mongolia University Hohhot 010021China Department of Mathematics Hohhot Minzu College Hohhot 010051 China

In this paper, we introduce the class of Hamilton type operators and study various properties of this class. We show that every Hamilton type operator with property（β） or（δ） is decomposable. In addition,we prove that a Hamilton type operator T satisfies property（β）, Dunford＇s property（C） and Weyl＇s theorem if and only if its adjoint does.

关键词： Hamilton type operators property (β) property (C) decomposability Weyl's theorem

Transcriptome sequencing and metabolome analysis reveal the mechanism of Shuanghua Baihe Tablet in the treatment of oral mucositis

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Chinese Journal of Natural Medicines 2021年第12期19卷 930-943页

作者： GENG Qi-shun liU Rui-Juan shen Zhi-Bo WEI Qian ZHENG Yuan-Yuan JIA Lan-Qi WANG Long-Hao li li-Feng li Jun XUE Wen-Hua Department of Pharmacy the First Affiliated Hospital of Zhengzhou UniversityZhengzhou 450052China Engineering Laboratory for Digital Telemedicine Service The first Affiliated Hospital of Zhengzhou UniversityZhengzhou 450052China

Oral mucositis(OM) caused by cancer therapy is the most common adverse reaction in the radiotherapy of head and neck tumors. In severe cases, it can lead to the interruption of treatment, which affects the control of the disease and the quality of *** Baihe Tablet(SBT) is a traditional Chinese medicine(TCM) formula, which is administerd to treat OM in China. It has been clinically effective for more than 30 years, but the underlying mechanism is not completely understood. With the development of multiple omics, it is possible to explore the mechanism of Chinese herbal compound prescriptions. Based on transcriptomics and metabolomics, we explored the underlying mechanism of SBT in the treatment of OM. An OM model of rats was established by 5-FU induction, and SBT was orally administered at dosages of 0.75 and 3 g·kg;·d;. In order to search for SBT targets and related metabolites, the dysregulated genes and metabolites were detected by transcriptomics and metabolomics. Immune related indicators such as interleukin-17(IL-17) and tumor necrosis factor-α(TNF-α) were detected by EliSA. Treg cell disorders was analyzed by flow cytometry. Our results showed that SBT significantly alleviated the symptoms of OM rats and the inflammatory infiltration of ulcer *** SBT administration, inflammatory related metabolic pathways including linoleic acid metabolism, valine, leucine and isoleucine biosynthesis were significantly altered. Furthermore, the production of proinflammatory factors like IL-17 and TNF-α, were also dramatically reduced after SBT administration. Besides, the infiltration degree of Treg cells in the spleen of OM modeling rats was significantly improved by SBT administration, thus maintaining the immune balance of the body. The current study demonstrates that SBT regulates inoleic acid metabolism, glycerophospholipid metabolism and amino acid metabolism, and inhibits IL-17/TNF signal transduction to restore Treg and Th17 cell homeostasis in OM

关键词： Oral mucositis Shuanghua Baihe tablet Transcriptomics Metabolomics IL-17/TNF signal pathway

The seamless model for three-dimensional datum transformation

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Science China Earth Sciences 2012年第12期55卷 2099-2108页

作者： li BoFeng shen YunZhong li WeiXiao GNSS Research Centre Department of Spatial SciencesCurtin University of TechnologyGPO Box U1987PerthWA 6845Australia Department of Surveying and Geo-informatics Engineering Tongji UniversityShanghai 200092China Centre for Spatial Information Science and Sustainable Development Tongji UniversityShanghai 200092China

With extensive applications of space geodesy, three-dimensional datum transformation model has been necessarily used to transform the coordinates in the different coordinate *** essence is to predict the coordinates of non-common points in the second coordinate system based on their coordinates in the first coordinate system and the coordinates of common points in two coordinate ***, the computation of seven transformation parameters and the transformation of noncommon points are individually implemented, in which the errors of coordinates are taken into account only in the second system although the coordinates in both two systems are inevitably contaminated by the random ***, the coordinate errors of non-common points are disregarded when they are transformed using the solved transformation *** we propose the seamless (rigorous) datum transformation model to compute the transformation parameters and transform the non-common points integratively, considering the errors of all coordinates in both coordinate *** a result, a nonlinear coordinate transformation model is *** on the Gauss-Newton algorithm and the numerical characteristics of transformation parameters, two linear versions of the established nonlinear model are individually *** the least-squares collocation (prediction) method is employed to trivially solve these linear ***, the simulation experiment is carried out to demonstrate the performance and benefits of the presented *** results show that the presented method can significantly improve the precision of the coordinate transformation, especially when the non-common points are strongly correlated with the common points used to compute the transformation parameters.

关键词： coordinate transformation collocation total least squares Bursa model Gauss-Newton method

Effects of cerium doping position on physicochemical properties and catalytic performance in methanol total oxidation

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Journal of Rare Earths 2018年第8期36卷 811-818页

作者： shen Zhang Yuyu Guo Xingying li Zhe li College of Chemistry and Chemical Engineering Taiyuan University of Technology

The physicochemical properties of Pd and Pd-Pt catalysts which possess different Ce doping position were investigated by techniques of TEM, XRD, N2 adsorption-desorption, XPS and FT-IR. The catalytic performance for methanol total oxidation was examined to study the effects of Ce adding ***2-Al2 O3-TiO2（CAT） catalysts that Ce is directly introduced into support show higher reactivity and CO2 selectivity than CeO2/Al2 O3-TiO2（Ce/AT） samples in which Ce is loaded by impregnation *** characterization results reveal that the Ce doping position does not cause obvious otherness of basic crystalline phase and mesoporous structure of support. However, the Ce doping position affects the pore shapes of support and then influences the pore diameter. CAT catalysts possess more abundant adsorbed oxygen and more Ti3＋ can transform the more gaseous oxygen into the active oxygen species on the catalyst surface, which is beneficial to the reaction. The Al-O-Ti bridges in CAT facilitate the cooperation of Al and Ti species, which further speeds up the reaction rate.

关键词： Ce doping position Methanol total oxidation Adsorbed oxygen Al-O-Ti bridges Rare earths

Numerical investigation on the flow and thermal behaviors of the volumetric solar receivers with different morphologies

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Science China(Technological Sciences) 2024年第9期67卷 2749-2757页

作者： DU shen li Dong li MengJie HE Yaling National Innovation Platform(Center)for Industry-Education Integration of Energy Storage Technology Key Laboratory of Thermo-Fluid Science and Engineering of Ministry of EducationXi’an Jiaotong UniversityXi’an 710049China

Morphologies of the porous materials influence the processes of solar radiation transport, flow, and thermal behaviors within volumetric solar receivers. A comprehensive comparative study is conducted by applying pore scale numerical simulations on volumetric solar receivers featuring various morphologies, including Kelvin, Weaire-Phelan, and foam configurations. The idealized unit cell and X-ray computed tomography scan approaches are employed to reconstruct pore scale porous *** Carlo ray tracing and pore scale numerical simulations are implemented to elucidate the radiative, flow, and thermal behaviors of distinct receivers exposed to varying thermal boundary conditions and real irradiation situations. The findings demonstrate that the foam structure exhibits greater solar radiation absorptivity, while Kelvin and Weaire-Phelan structures enhance the penetration depth under non-perpendicular solar irradiation. In comparison with Kelvin and Weaire-Phelan configurations, the foam structure presents efficient convective heat transfer, with the Weaire-Phelan structure showing pronounced thermal non-equilibrium phenomena. The variance in convective heat transfer coefficient between Kelvin and Weaire-Phelan configurations is approximately 8.4%. The foam structure exhibits higher thermal efficiency and flow resistance under nonperpendicular irradiation compared to Kelvin and Weaire-Phelan structures, attributed to its smaller pore size and intricate flow channels. An increase of 1.3% in thermal efficiency is observed with a substantial rise in pressure drop of 32.2%.

关键词： volumetric solar receiver porous morphology pore scale method solar radiation absorption thermal performance flow resistance

Preparation of LaFe_(0.95)Pd_(0.05)O_3 perovskites and their catalytic performances in methane combustion

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Journal of Natural Gas Chemistry 2012年第2期21卷 113-118页

作者： Xiaojing Zhang Yong li Huaju li Wenjie shen State Key Laboratory of Catalysis Dalian Institute of Chemical PhysicsChinese Academy of SciencesDalian 116023LiaoningChina

The physic-chemical properties of LaFe0.95Pd0.05O3 perovskites were strongly dependent on the temperature of calcination. Most of the organic substances and inorganic impurities were readily removed at 723 K but single-phase and well crystallized perovskite structure was formed at 873 K. With further raising the calcination temperature, the crystallite size of LaFe0.95Pd0.05O3 increased considerably. The LaFe0.95Pd0.05O3 sample that calcined at 1073 K showed only comparable activity as the reference LaFeO3 catalyst, in particular below 923 K, but pre-treatment with the reaction gas at 1223 K resulted in significantly enhanced activity due to the generation of active PdO species on the surface. The hysteresis feature upon heating-cooling cycle further confirmed the strong interaction between Pd and LaFeO3 in the perovskite structure.

关键词： perovskite LaFe0.95Pd0.05O3 calcination temperature pre-treatment methane combustion