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Imaginary Modules over the Affine Nappi-Witten Algebra

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Acta Mathematica Sinica,English Series 2022年第6期38卷 1041-1053页

作者： Yi xin bao Yan An CAI School of Sciences Harbin Institute of Technology(Shenzhen)Shenzhen 518055P.R.China Department of Mathematics Soochow UniversitySuzhou 215006P.R.China

In this paper,we consider the imaginary highest weight modules and the imaginary Whittaker modules for the affine Nappi-Witten *** show that simple singular imaginary Whittaker modules at level(κ、c)(κ∈C~*)are simple imaginary highest weight *** necessary and sufficient conditions for these imaginary modules to be simple are *** simple imaginary modules are classified.

关键词： Affine Nappi-Witten algebra imaginary Verma modules imaginary highest weight modules imaginary Whittaker modules simple modules

Magneto-Optic Fiber Gratings Useful for Dynamic Dispersion Management and Tunable Comb Filtering

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Chinese Physics Letters 2010年第6期27卷 225-228页

作者： WU bao-Jian LU xin QIU Kun Key Lab of Broadband Optical Fiber Transmission and Communication Networks of the Ministry of Education University of Electronic Science and Technology of China Chengdu 611 731

Intelligent control of dispersion management and tunable comb filtering in optical network appfications can be performed by using magneto-optic fiber Bragg gratings （MFBGs）. When a nonuniform magnetic field is applied to the MFBG with a constant grating period, the resulting grating response is equivalent to that of a conventional chirped grating. Under a linearly nonuniform magnetic field along the grating, a linear dispersion is achieved in the grating bandgap and the maximal dispersion slope can come to 1260ps/nm2 for a l0-mm-long fiber grating at 1550nm window. Similarly, a Gaussian-apodizing sarnpled MFBG is also useful for magnetically tunable comb filtering, with potential application to clock recovery from return-to-zero optical signals and optical carrier tracking.

关键词： Filters Filtration Dispersions Spraying Dispersants Magnetic field Fields Uses Fibres Comminution

Stability conditions of explicit integration algorithms when using 3D viscoelastic artificial boundaries

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Earthquake Engineering and Engineering Vibration 2022年第4期21卷 929-945页

作者： bao xin Liu Jingbo Li Shutao Wang Fei Lu Xihuan Department of Civil Engineering Tsinghua UniversityBeijing 100084China Institute of Defence Engineering AMSPLABeijing 100036China College of Defense Engineering Army Engineering University of PLANanjing 210007China

Viscoelastic artificial boundaries are widely adopted in numerical simulations of wave propagation *** explicit time-domain integration algorithms are used,the stability condition of the boundary domain is stricter than that of the internal region due to the influence of the damping and stiffness of an viscoelastic artificial *** lack of a clear and practical stability criterion for this problem,however,affects the reasonable selection of an integral time step when using viscoelastic artificial *** this study,we investigate the stability conditions of explicit integration algorithms when using three-dimensional(3D)viscoelastic artificial boundaries through an analysis method based on a local *** boundary subsystems that can represent localized characteristics of a complete numerical model are established,and their analytical stability conditions are derived from and further compared to one *** stability of the complete model is controlled by the corner regions,and thus,the global stability criterion for the numerical model with viscoelastic artificial boundaries is ***,by analyzing the impact of different factors on stability conditions,we recommend a stability coefficient for practically estimating the maximum stable integral time step in the dynamic analysis when using 3D viscoelastic artificial boundaries.

关键词： explicit time domain integration viscoelastic artificial boundary numerical stability local subsystem transfer matrix

Seismic wave input method for three-dimensional soil-structure dynamic interaction analysis based on the substructure of artificial boundaries

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Earthquake Engineering and Engineering Vibration 2019年第4期18卷 747-758页

作者： Liu Jingbo Tan Hui bao xin Wang Dongyang Li Shutao Department of Civil Engineering Tsinghua University

The method of inputting the seismic wave determines the accuracy of the simulation of soil-structure dynamic interaction. The wave method is a commonly used approach for seismic wave input, which converts the incident wave into equivalent loads on the cutoff boundaries. The wave method has high precision, but the implementation is complicated, especially for three-dimensional models. By deducing another form of equivalent input seismic loads in the fi nite element model, a new seismic wave input method is proposed. In the new method, by imposing the displacements of the free wave fi eld on the nodes of the substructure composed of elements that contain artifi cial boundaries, the equivalent input seismic loads are obtained through dynamic analysis of the substructure. Subsequently, the equivalent input seismic loads are imposed on the artifi cial boundary nodes to complete the seismic wave input and perform seismic analysis of the soil-structure dynamic interaction model. Compared with the wave method, the new method is simplifi ed by avoiding the complex processes of calculating the equivalent input seismic loads. The validity of the new method is verifi ed by the dynamic analysis numerical examples of the homogeneous and layered half space under vertical and oblique incident seismic waves.

关键词： soil-structure dynamic interaction seismic wave input wave method equivalent input seismic loads substructure of artifi cial boundaries

On Universally Left-stability of ε-Isometry

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Acta Mathematica Sinica,English Series 2013年第11期29卷 2037-2046页

作者： Ling xin bao Li xin CHENG Qing Jin CHENG Duan Xu DAI School of Mathematical Sciences Xiamen University

Let X, Y be two real Banach spaces and ε≥0. A map f ： X → Y is said to be a standard ε-isometry if│││f/（x） - f（y）││ - ]ix - Y││x-y││ ε for all x,y C X and with f（O） = O. We say that a pair of Ban... 详细信息

Let X, Y be two real Banach spaces and ε≥0. A map f ： X → Y is said to be a standard ε-isometry if│││f/（x） - f（y）││ - ]ix - Y││x-y││ ε for all x,y C X and with f（O） = O. We say that a pair of Banach spaces （X, Y） is stable if there exists γ〉 0 such that, for every such ε and every standard v-isometry f ： X → Y, there is a bounded linear operator T ： L（f） → f（X） → X so that ││Tf（x） - x││ ≤γε for all x E X. X（Y） is said to be universally left-stable if （X, Y） is always stable for every Y（X）. In this paper, we show that if a dual Banach space X is universally left-stable, then it is isometric to a complemented w＊-closed subspace of ∞ （1） for some set F, hence, an injective space; and that a Banach space is universally left-stable if and only if it is a cardinality injective space; and universally left-stability spaces are invariant.

关键词： ε-Isometry linear isometry stability injective space Banach space

Electrodeposited Sn-based Catalysts for CO2 Electroreduction

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Chinese Journal of Structural Chemistry 2020年第2期39卷 206-213,183页

作者： YE Ke WANG Guo-Xiong bao xin-He State Key Laboratory of Catalysis Dalian National Laboratory for Clean EnergyDalian Institute of Chemical PhysicsChinese Academy of SciencesDalian 116023China Key Laboratory of Superlight Materials and Surface Technology of Ministry of Education College of Materials Science and Chemical EngineeringHarbin Engineering UniversityHarbin 150001China

Electrochemical CO2 reduction reaction(CO2RR) has been considered as a feasible avenue for simultaneous conversion of renewable energy and CO2. Economic and technical analysis suggests that the production of valuable C1 chemicals such as formic acid and CO is the most economically practicable route for CO2RR. This perspective summarizes the performance of electrodeposited Sn-based catalysts for C1 chemicals production and the relative mechanism of CO2RR. Further fundamental understanding and industrial applications of electrodeposited Sn-based catalysts in CO2 electrolyzer device are also discussed.

关键词： tin-based catalysts electrodeposition technology alloy interface electrochemical carbon dioxide reduction reaction

Reductive recovery of manganese from low-grade manganese dioxide ore using toxic nitrocellulose acid wastewater as reductant

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International Journal of Minerals,Metallurgy and Materials 2018年第9期25卷 990-999页

作者： Yong-tao Zhang Zhi-gang Dan Ning Duan bao-ping xin School of Petroleum and Environment Engineering Yan'an University School of Materials Science & Engineering Beijing Institute of Technology Technology Center for Heavy Metal Cleaner Production Engineering Chinese Research Academy of Environmental Sciences

The hydrometallurgical strategy of extracting Mn from low-grade Mn ores has attracted attention for the production of electrolytic manganese metal(EMM). In this work, the reductive dissolution of low-grade Mn O2 ores using toxic nitrocellulose acidic wastewater(NAW) as a reductant was investigated for the first time. Under the optimized conditions of an Mn O2 ore dosage of 100 g·L-1, an ore particle size of-200 mesh, concentrated H2 SO4-to-NAW volume ratio of 0.12, reaction temperature of 90°C, stirring speed at 160 r·min-1, and a contact time of 120 min, the reductive leaching efficiency of Mn and the total organic carbon(TOC) removal efficiency of NAW reached 97.4% and 98.5%, respectively. The residual TOC of 31.6 mg·L-1 did not adversely affect the preparation of EMM. The current process offers a feasible route for the concurrent realization of the reductive leaching of Mn and the treatment of toxic wastewater via a simple one-step process.

关键词： low-grade manganese dioxide ore nitrocellulose acid wastewater sulfuric acid leaching Mn reductive dissolution electrolytic manganese metal

Impact of vegetation restoration on hydrological processes in the middle reaches of the Yellow River,China

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Forestry Studies in China 2009年第4期11卷 209-218页

作者： xin Zhong-bao YU xin-xiao Key Laboratory of Soil and Water Conservation and Desertification Combating of the Ministry of Education Beijing Forest Univer-sity 100083 P. R. China

Sediment discharge from the Yellow River originates mainly from the drainage area between Hekouzhen and Longmen, i.e., the Helong area. Spatial-temporal variations of the vegetation cover in this area during the 1981-2007 period have been investigated using GIMMS and SPOT VGT NDVI data. We have also analyzed the interannual variations in vegetation cover and changes in annual runoff and sediment discharge, the consequences from precipitation change and the Grain for Green Project （GGP）. The results show that vegetation cover of the Helong area has increased during the 1981-2007 period. The northwestern part the Helong area, where the flat sandy lands are covered by grass, has experienced the largest increase. The region where the vegetation cover has declined is largely found in the southern and southeastern Helong area, which is a gullied hilly area or forested. Although precipitation was relatively low during the 1999-2007 period, the vegetation cover showed a significant increase in the Helong area, due to the implementation of the GGP. During this period, the most significant improvement in the vegetation cover occurred mainly in the gullied hilly areas of the Loess Plateau, such as the drainage basins of the Kuyehe and Tuweihe rivers and the middle and lower reaches of the Wudinghe and Yanhe rivers. A comparison of the average annual maximum NDVI between the earlier （1998-2002） stage and the next five years （2003-2007） of the GGP indicates that the areas with increases of 10% and 20% in NDVI account for 72.5% and 36.4% of the total area, respectively. Interannual variation of annual runoff and sediment discharge shows a declining trend, especially since the 1980s, when the decrease became very obvious. Compared with the 1950-1969 period, the average runoff during the 1980-2007 period was reduced by 34.8 × 10^8 m3 and the sediment discharge by 6.4 ×10^8 t, accounting for 49.4% and 64.9% of that in the 1950-1969 period, respectively. There is a positive correlati

关键词： middle reaches of the Yellow River Hekouzhen to Longmen area (Helong area) vegetation restoration Grain forGreen Project (GGP) runoff and sediment

Estimation of future water resources of Xiangjiang River Basin with VIC model under multiple climate scenarios

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Water Science and Engineering 2017年第2期10卷 87-96页

作者： Guo-qing Wang Jian-yun Zhang Yue-ping Xu Zhen-xin bao xin-yue Yang State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering Nanjing Hydraulic Research Institute Research Center for Climate Change Ministry of Water Resources Institute of Hydrology and Water Resources Civil EngineeringZhejiang University College of Hydrology and Water Resources Hohai University

Variation trends of water resources in the Xiangjiang River Basin over the coming decades have been investigated using the variable infiltration capacity(VIC) model and 14 general circulation models'(GCMs') projections under the representative concentration pathway(RCP4.5) scenario. Results show that the Xiangjiang River Basin will probably experience temperature rises during the period from 2021 to2050, with precipitation decrease in the 2020 s and increase in the 2030 s. The VIC model performs well for monthly discharge simulations with better performance for hydrometric stations on the main stream of the Xiangjiang River than for tributary catchments. The simulated annual discharges are significantly correlated to the recorded annual discharges for all the eight selected target stations. The Xiangjiang River Basin may experience water shortages induced by climate change. Annual water resources of the Xiangjiang River Basin over the period from 2021 to 2050 are projected to decrease by 2.76% on average within the range from-7.81% to 7.40%. It is essential to consider the potential impact of climate change on water resources in future planning for sustainable utilization of water resources.

关键词： Water resources Climate change VIC model Xiangjiang River Basin Climate scenarios Hydrological modeling