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乌玛高速沙漠段风沙环境特征及格状沙丘移动规律

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水土保持研究 2025年第1期32卷 160-171页

作者：李良英王振强王旭辛国伟李琦吕乐乐兰州交通大学土木工程学院

[目的]沙丘移动与风沙环境特征和沙丘形态具有直接关系，探究多种因素作用下的格状沙丘移动规律，能为沙区公路风沙防治提供科学依据。[方法]以乌玛高速沙漠段格状沙丘为研究对象，基于当地气象数据、Google Earth卫星影像，研究了2019... 详细信息

[目的]沙丘移动与风沙环境特征和沙丘形态具有直接关系，探究多种因素作用下的格状沙丘移动规律，能为沙区公路风沙防治提供科学依据。[方法]以乌玛高速沙漠段格状沙丘为研究对象，基于当地气象数据、Google Earth卫星影像，研究了2019—2021年乌玛高速沙漠段K167+300,K172+300,K177+300里程处风沙环境及格状沙丘的形态演变和移动规律。[结果](1)研究区年平均起沙风速介于6.07～6.84 m/s,春夏为主要输沙季节，主风向为西北风，次风向为东南风；年输沙势介于31.77～38.89 VU,方向变率指数(RDP/DP)介于0.73～0.78,属于低风能环境、中变率风况。(2)研究区自东北向西南方向，格状沙丘主梁向东偏移，副梁向南偏移，主副梁走向几乎保持垂直，沙丘形态整体上变化较小；格状沙丘的主副梁长度、主副梁间距、沙丘高度均呈现出增加的趋势，主副梁长度增长率、主副梁偏移率呈减小趋势。(3)沙丘移动方向介于140.43°～152.64°,与年RDD变化基本一致，即向东南偏移；沙丘平均高度介于5.24～8.31 m,沙丘移动速率介于2.31～2.86 m/a,两者表现为负相关关系。(4)输沙势、年均温度与沙丘移动速率为正相关关系，相较而言，年均温度对沙丘移动速率的影响更为显著；年均降水量、植被覆盖度与沙丘移动速率为负相关关系，其中年均降水量对移动速率的影响尤为重要。[结论]格状沙丘的移动与当地风况、降水量、温度、植被覆盖度及沙丘自身形态息息相关，其中输沙势及温度增加会加速沙丘前移，不利于对风沙的防治，而提高降水量及植被覆盖度，对防治沙丘移动引起的公路风沙灾害具有积极作用。

关键词：格状沙丘输沙势空间插值沙丘移动形态演变

Three-dimensional electric potential induced by a point singularity in a multilayered dielectric medium

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Applied Mathematics and Mechanics(English Edition) 2019年第9期40卷 1327-1334页

作者： xu wang P. SCHIAVONE School of Mechanical and Power Engineering East China University of Science and Technology Shanghai 200237 China Department of Mechanical Engineering University of Alberta 10-203 Donadeo Innovation Centre for Engineering Edmonton Alberta T6G 1H9 Canada

A simple and effective method is proposed to derive the three-dimensional electric potential induced by a point singularity of any type in an N-phase dielectric medium composed of N-2 intermediate dielectric layers of equal thickness encased in two semi-infinite dielectric media. The point singularity can include a point charge or a point electric dipole. The original boundary value problem for the N-phase medium is reduced to the determination of a single unknown three-dimensional harmonic function through satisfaction of the continuity conditions across all of the N-1 perfect planar interfaces. The single harmonic function can be completely determined after analytically solving the resulting linear recurrence relations, which are independent of the type and the specific location of the singularity. When the singularity is a point charge, we obtain the self-energy of the point charge expressed in terms of a single function and the Coulomb force on the point charge expressed in terms of the negative derivative of this function.

关键词： multilayered dielectric medium point charge point electric dipole linear recurrence relation analytical solution

Multistate circularly polarized luminescence switches based on dual stimuli-responsive chiral[2]rotaxanes

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Science China Chemistry 2024年第12期67卷 4202-4211页

作者： Wei-Tao xu xue Li Xiao-Qin xu xu-Qing wang Hai-Bo Yang Wei wang Wuhu Hospital East China Normal University(The Second People’s HospitalWuhu)Wuhu 241001China Shanghai Key Laboratory of Green Chemistry and Chemical Processes State Key Laboratory of Petroleum Molecular and Process EngineeringSchool of Chemistry and Molecular EngineeringEast China Normal UniversityShanghai 200062China Shanghai Center of Brain-inspired Intelligent Materials and Devices East China Normal UniversityShanghai 200241China

Aiming at the construction of novel multistate circularly polarized luminescence(CPL)switches,dual stimuli-responsive chiral[2]rotaxanes towards anions and light have been designed and *** the light-controlled on/off F?rster resonance energy transfer(FRET)switching between the emissive stoppers and anion-induced controllable motions of the chiral wheel for the precise regulations of chirality information transfer from the chiral wheel to the emissive stoppers,precisely switching between four CPL emission states with varied emission wavelengths and dissymmetry factors has been successfully realized,making them a promising platform for practical uses such as information storage and *** proof-of-concept study not only provides a novel design strategy for multistate CPL switching but also contributes excellent candidates for the construction of novel smart chiral luminescent materials.

关键词： mechanically interlocked molecules Förster resonance energy transfer aggregation-induced emission pillararene spiropyran

Dual Interval Optimization Based Trading Strategy for ESCO in Day-ahead Market with Bilateral Contracts

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Journal of Modern Power Systems and Clean Energy 2020年第3期8卷 582-590页

作者： Shengmin Tan xu wang Chuanwen Jiang Key Laboratory of Control of Power Transmission and Conversion Ministry of EducationShanghai Jiao Tong UniversityShanghai 200240China

Being capable of aggregating multiple energy resources, the energy service company(ESCO) has been regarded as a promising alternative for improving power system flexibility and facilitating the consumption of renewable resources in the electricity market. Considering the uncertain variables in day-ahead(DA) market trading, an ESCO can hardly determine their accurate probability distribution functions. Traditional interval optimization methods are used to process these uncertain variables without specific probability distribution ***, the lower and upper bounds of the intervals may change due to extreme weather conditions and other emergent events. Hence, a dual interval optimization based trading strategy(DIOTS) for ESCO in a DA market with bilateral contracts(BCs) is proposed. First, we transfer the dual interval optimization model into a simple model consisting of several interval optimization models. Then, a pessimistic preference ordering method is applied to solve the derived model. Case studies illustrating an actual test system corroborate the validity and the robustness of the proposed model, and also reveal that ECSO is critical in improving power system flexibility and facilitating the ability of absorbing renewable resources.

关键词： Dual interval optimization energy service company(ESCO) day-ahead market bilateral contract market

Hydrodynamic scaling and wave force estimation of offshore structures

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Acta Mechanica Sinica 2020年第6期36卷 1228-1237,I0002页

作者： Jifu Zho Ling Chen xu wang CAS Key Laboratory for Mechanics in Fluid Solid Coupling Systems Institute of MechanicsChinese Academy of SciencesBeijing100190China School of Engineering Sciences University of Chinese Academy of SciencesBeijing100049China

Offshore structures are generally classified as small-scale structures or large-scale *** wave forces are then estimated by Morison equation and diffraction/radiation theories,***,the classification criterion is not well *** the present paper,a numerical wave flume is established to simulate the wave forces acting on a fixed and vertical surface-piercing circular cylinder under linear *** solving Navier–Stokes equation and Euler equation with free surface involved,respectively,the viscous force and inertia force are separated *** variation of viscous force and inertia force with the cylinder diameter to wave length ratio is discussed in *** scale intervals for significant viscous and diffraction effects are *** error caused by neglecting viscous and diffraction forces is quantitatively *** on these analysis,the concept of medium-scale structure is proposed and the classification criteria for small-,medium-and large-scale structures are *** the meantime,the estimation methods of wave forces for different scales of structures are suggested.

关键词： Wave force Viscous effect Diffraction effect Medium-scale structure Numerical wave flume

Shear-wave velocity structures of the shallow crust beneath the Ordos and Sichuan Basins from multi-frequency direct P-wave amplitudes in receiver functions

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Science China Earth Sciences 2022年第5期65卷 810-823页

作者： Chenxiao TANG Ling CHEN xu wang State Key Laboratory of Lithospheric Evolution Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029China Deep Earth Science Excellence and Innovation Center Chinese Academy of SciencesGuangzhou 510640China College of Earth and Planetary Sciences University of Chinese Academy of SciencesBeijing 100049China

As the two largest cratonic basins in China,the Ordos Basin and the Sichuan Basin are of key importance for understanding the evolutionary history of the Chinese *** this study,the shear-wave velocity(V_(S))structures of the shallow crust(depth up to 10 km)beneath the two basins are imaged based on the frequency-dependence of direct P-wave amplitudes in receiver *** teleseismic data used in the study came from 160 broadband seismic stations,including permanent and temporary *** results show that the V_(S) and the thickness of the sediments in the Ordos Basin and the Sichuan Basin are respectively lower and thicker in the west than in the *** the Ordos Basin,the shallow crustal V_(S) increases gradually from 2.10 km s^(−1)in the northwest to 2.65 km s^(−1)in the southeast and the thickest sediments are 7–8 km in the northwest and 5 km in the *** the Sichuan Basin,the shallow crustal V_(S) increases from 2.4 km s^(−1) in the west to 2.7 km s^(−1)in the east and the thickness of the sediments decreases from>7 km in the west to 6 km in the *** east-west difference of the shallow crustal structures of the two basins may have been controlled by the Cenozoic India-Eurasia *** western parts of the basins near the collision have a higher deposition rate,while in the parts inside the basins far from the collision,the V_(S) slowly increases with depth,indicating that these areas have experienced a more uniform deposition *** addition,both basins are characterized by velocity structures that are higher along the edges and lower inside of the *** edges of the basins suffered strong denudation due to the uplifting and deformation influenced by tectonic *** downward gradient of the shear-wave velocity beneath the Ordos Basin is twice that of the Sichuan Basin,which may be caused by the different deposition and denudation rates of the two basins resulting from differences in structural evolution and thermal

关键词： Shallow crustal velocity structures Receiver function Frequency dependence Ordos Basin Sichuan Basin Tectonic evolution

Multi-Attribute Preferences Mining Method for Group Users with the Process of Noise Reduction

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Journal of Computer Science & Technology 2021年第4期36卷 944-960页

作者： Qing-Mei Tan xu-Na wang College of Economic and Management Nanjing University of Aeronautics and AstronauticsNanjing 211106China Research Base for Civilian-Military Integration Development in Jiangsu Province Nanjing 211106China

Traditional researches on user preferences mining mainly explore the user’s overall preferences on the project,but ignore that the fundamental motivation of user preferences comes from their attitudes on some attributes of the *** addition,traditional researches seldom consider the typical preferences combination of group users,which may have influence on the personalized service for group *** solve this problem,a method with noise reduction for group user preferences mining is proposed,which focuses on mining the multi-attribute preference tendency of group ***,both the availability of data and the noise interference on preferences mining are considered in the algorithm *** the process of generating group user preferences,a new path is used to generate preference keywords so as to reduce the noise ***,the Gibbs sampling algorithm is used to estimate the parameters of the ***,using the user comment data of several online shopping websites as experimental objects,the method is used to mine the multi-attribute preferences of different *** proposed method is compared with other methods from three aspects of predictive ability,preference mining ability and preference topic *** results show that the method is significantly better thap other existing methods.

关键词： preferences mining group user multi-attribute noise reduction noise interference

Combined effects of topography and bottom friction on shoaling internal solitary waves in the South China Sea

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Applied Mathematics and Mechanics(English Edition) 2019年第4期40卷 421-434页

作者： Dalin TAN Jifu ZHOU xu wang Zhan wang Key Laboratory for Mechanics in Fluid Solid Coupling Systems Institute of MechanicsChinese Academy of Sciences School of Engineering Sciences University of Chinese Academy of Sciences

A numerical study to a generalized Korteweg-de Vries (KdV) equation is adopted to model the propagation and disintegration of large-amplitude internal solitary waves (ISWs) in the South China Sea (SCS). Based on theoretical analysis and in situ measurements, the drag coefficient of the Chezy friction is regarded as inversely proportional to the initial amplitude of an ISW, rather than a constant as assumed in the previous studies. Numerical simulations of ISWs propagating from a deep basin to a continental shelf are performed with the generalized KdV model. It is found that the depression waves are disintegrated into several solitons on the continental shelf due to the variable topography. It turns out that the amplitude of the leading ISW reaches a maximum at the shelf break, which is consistent with the field observation in the ***, a dimensionless parameter defining the relative importance of the variable topography and friction is presented.

关键词： internal solitary wave(ISW) South China Sea(SCS) Chezy friction vari-able topography

SIMULATION RESEARCH ON THE AFTERBURNING DYNAMIC CHARACTERISTICS OF ENGINE CONTROL SYSTEM

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Chinese Journal of Aeronautics 1990年第1期5卷 23-33页

作者： Kejiu, Mao xu, wang Beijing Univ of Aeronautics and Astronautics Beijing China

Static and dynamic mathematical models for a new type of engine and its actual hydraulic control system are proposed. A nonlinear mathematical model is used for the engine and afterburner fuel control system. With programs formed on the basis of these models, the static and dynamic close loop characteristics of this engine control system under afterburning condition have been analyzed in detail. Satisfactory results and valuable conclusions have been obtained. The results are useful for solving many practical problems of the engine control system.

关键词： Control Systems Hydraulic Drive Dynamics Mathematical Models