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Analytical solution of ground-borne vibration due to a spatially periodic harmonic moving load in a tunnel embedded in layered soil

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2023年第7期24卷 637-652页

作者： Lihui XU meng MA Key Laboratory of Urban Underground Engineering of Ministry of Education Beijing Jiaotong UniversityBeijing 100044China School of Civil Engineering Beijing Jiaotong UniversityBeijing 100044China

In this study,we propose a novel coupled periodic tunnel–soil analytical model for predicting ground-borne vibrations caused by vibration sources in *** problem of a multilayered soil overlying a semi-infinite half-space was solved using the transfer matrix *** account for the interactions between the soil layer and tunnel structure,the transformation characteristics between cylindrical waves and plane waves were considered and used to convert the corresponding wave potentials into forms in terms of the Cartesian or cylindrical coordinate *** induced ground-borne vibration was obtained analytically by applying a spatially periodic harmonic moving load to the tunnel *** accuracy and efficiency of the proposed model were verified by comparing the results under a moving constant and harmonic load with those from previous ***,the response characteristics under a spatially periodic harmonic moving load were identified,and the effects of a wide range of factors on the responses were systematically *** numerical results showed that moving and Doppler effects can be caused by a spatially periodic harmonic moving *** critical frequency and frequency bandwidth of the response are affected by the load type,frequency,velocity,and wavenumber in one periodicity *** the tunnel depth is an efficient way to reduce ground-borne *** effect of vibration amplification on the free surface should be considered to avoid excessive vibration levels that disturb residents.

关键词： Coupled tunnel-soil model Spatially periodic load Transfer matrix method Wave transformation Parametric analysis

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DGMRES Method Augmented with Eigenvectors for Computing the Drazin-inverse Solution of Singular Linear Systems

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Acta Mathematicae Applicatae Sinica 2016年第2期32卷 549-558页

作者： Bin meng College of Science Nanjing University of Aeronautics and Astronautics

The DGMRES method for solving Drazin-inverse solution of singular linear systems is generally used with restarting. But the restarting often slows down the convergence and DGMRES often stagnates. We show that adding some eigenvectors to the subspace can improve the convergence just like the method proposed by R. Morgan in [R. Morgan, A restarted GMRES method augmented with eigenvectors, SIAM J. Matrix Anal App1., 16： 1154-1171, 1995. We derive the implementation of this method and present some numerical examples to show the advantages of this method.

关键词： Drazin-inverse DGMRES Krylov subspace iterative method eigenvector

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DYNAMIC PORTFOLIO CHOICE UNDER THE TIME-VARYING,JUMPS,AND KNIGHT UNCERTAINTY OF ASSET RETURN PROCESS

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Journal of Systems Science & Complexity 2012年第5期25卷 896-908页

作者： Chaolin HE Weidong meng School of Management Engineering Anhui Polytechnic University College of Economics and Business Administration Chongqing University

By introducing a stochastic element to the double-jump diffusion framework to measure the Knight uncertainty of asset return process, this paper builds the model of dynamic portfolio choice, which maximizes the expected utility of terminal portfolio wealth. Through specifying the state function of uncertainty-aversion, it utilizes the max-min method to derive the analytical solution of the model to study the effect of the time-varying, jumps, and Knight uncertainty of asset return process on dynamic portfolio choice and their interactions. Results of comparative analysis show： The time-varying results in positive or negative intertemporal hedging demand of portfolio, which depends on the coefficient of investor＇s risk aversion and the correlation coefficient between return shift and volatility shift; the jumps in asset return overall reduce investor＇s demand for the risky asset, which can be enhanced or weakened by the jumps in volatility; due to the existing of the Knight uncertainty, the investor avoids taking large position on risky asset, and the resulting is the improving of portfolio＇s steady and immunity. At last, an empirical study is done based on the samples of Shanghai Exchange Composite Index monthly return data from January 1997 to December 2009, which not only tests the theoretical analysis but also demonstrates that the proposed method in the paper is useful from the aspect of portfotio＇s equivalent utility.

关键词： Conditional characteristic function dynamic portfolio jumps Knight uncertainty spec-tral generalized method of moments time-varying.

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Development of a Poly(vinyl chloride)-based Nitrate Ion-selective Electrode

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Chemical Research in Chinese Universities 2012年第6期28卷 957-962页

作者： HE meng-meng YANG Hui-zhong Key Laboratory of Advanced Control in Light Industry Process Ministry of Education Jiangnan University Wuxi 214122 P. R. China

The authors developed a nitrate ion-selective electrode（ISE） based on poly（vinyl chloride）（PVC） membrane with methyltrioctylammonium nitrate as a carrier and 1-decanol as a *** performance of the nitrate-sensitive membranes was optimized by tuning the composition of *** electrode exhibits a linear response with a Nernstian slope of（52±1.0） mV per decade for the nitrate ion concentration ranging from 5.8×10-5 mol/L to 1.0 mol/*** electrode can be used to detect a low concentration of nitrate ions down to 3×10-5 mol/L in a pH range of 2.1―11.5 without any *** advantage of the electrode includes simple preparation,short response time and good *** detection performance of the novel electrode on nitrate ions has been tested for water samples.

关键词： Poly(vinyl chloride)(PVC) Methyltrioctylammonium nitrate Nitrate-selective electrode Potentiometric sensor

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An Angle Structure Descriptor for Image Retrieval

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China Communications 2016年第8期13卷 222-230页

作者： meng Zhao Huaxiang Zhang Lili meng School of Information Science and Engineering Shandong Normal University Institute of Data Science and Technology Shandong Normal University

This paper presents an efficient image feature representation method, namely angle structure descriptor(ASD), which is built based on the angle structures of images. According to the diversity in directions, angle structures are defined in local blocks. Combining color information in HSV color space, we use angle structures to detect images. The internal correlations between neighboring pixels in angle structures are explored to form a feature vector. With angle structures as bridges, ASD extracts image features by integrating multiple information as a whole, such as color, texture, shape and spatial layout information. In addition, the proposed algorithm is efficient for image retrieval without any clustering implementation or model training. Experimental results demonstrate that ASD outperforms the other related algorithms.

关键词： image retrieval angle structure descriptor HSV color space local descriptor

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Nested Saturated Control of Uncertain Complex Cascade Systems Using Mixed Saturation Levels

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IEEE/CAA Journal of Automatica Sinica 2024年第5期11卷 1163-1174页

作者： meng Li Zhigang Zeng Wuhan National Laboratory for Optoelectronics Wuhan 430074 School of Artificial Intelligence and Automation Huazhong University of Science and TechnologyWuhan 430074China School of Artificial Intelligence and Automation Huazhong University of Science and TechnologyWuhan 430074 Key Laboratory of Image Processing and Intelligent Control of Education Ministry of China Wuhan 430074China

This study addresses the problem of global asymptotic stability for uncertain complex cascade systems composed of multiple integrator systems and non-strict feedforward nonlinear systems. To tackle the complexity inherent in such structures, a novel nested saturated control design is proposed that incorporates both constant saturation levels and state-dependent saturation levels. Specifically, a modified differentiable saturation function is proposed to facilitate the saturation reduction analysis of the uncertain complex cascade systems under the presence of mixed saturation levels. In addition, the design of modified differentiable saturation function will help to construct a hierarchical global convergence strategy to improve the robustness of control design scheme. Through calculation of relevant inequalities, time derivative of boundary surface and simple Lyapunov function,saturation reduction analysis and convergence analysis are carried out, and then a set of explicit parameter conditions are provided to ensure global asymptotic stability in the closed-loop systems. Finally, a simplified system of the mechanical model is presented to validate the effectiveness of the proposed method.

关键词： method saturation differentiable

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Enrichment of topographic road database for the purpose of routing and navigation

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International Journal of Digital Earth 2014年第5期7卷 411-431页

作者： meng Zhang Wei Yao Liqiu meng Department of Earth and Environmental Sciences Xi’an Jiaotong UniversityXi’anChina Department of Photogrammetry and Remote Sensing Technische Universitaet MuenchenMunichGermany Department of Cartography Technische Universitaet MuenchenMunichGermany

With growing demand on multi-purpose or multi-modal navigation,the route calculation needs to traverse semantically enriched road networks for different transportation ***,operational route planning algorithms reveal rather limited performances or their potential for comprehensive applications are constrained by the unavailable or insufficient interoperation among the under-lying geo-data that are separately maintained in different spatial *** overcome this limitation,a novel approach has been proposed to integrate the routing-relevant information from different data sources,which involves three processes:(1)automatic matching to identify the corresponding road objects between different datasets;(2)interaction to refine the automatic matching result;and(3)transferring the routing-relevant information from one data-set to *** process(1),the Delimited Stroke Oriented algorithm is employed to achieve the automatic data matching between different datasets,which has revealed a high matching rate and *** uncertain matching problems occur in areas where topological conditions are too complicated or *** remaining unmatched or wrongly matched objects are treated in process(2),with the help of a series of interaction *** the basis of refined matching results after the interaction,process(3)is dedicated to automatic integration of the routing-relevant information from different data sources.

关键词： data matching data integration routing-relevant geospatial data-set road network

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Core activated sludge communities are influenced little by immigration:Case study of a membrane bioreactor plant

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Journal of Environmental Sciences 2021年第4期33卷 244-255页

作者： Shaoqing Zhang Fangang meng School of Civil Engineering Guangzhou UniversityGuangzhou 510006China School of Environmental Science and Engineering Sun Yat-sen UniversityGuangzhou 510275China Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology Sun Yat-sen UniversityGuangzhou 510275China

Microbial immigrants arriving with influent wastewater may influence activated sludge(AS)***,the extent to which immigration impacts AS communities is still *** explore the intensity of immigration impact,we used sequencing technology to track the raw wastewater and AS communities from a membrane bioreactor plant over a 12-month *** first distinguished core populations from peripheral ones in both raw wastewater and AS based on their occurrence frequency and *** results showed that core OTUs(≥80%occurrence frequency)made up a large fraction(>90%)of total sequences,while peripheral OTUs composed the majority of all detected OTUs but merely occupied a few sequences.A significant difference in core communities between the influent and AS was found,as well as between the compositions of core and peripheral ***,the persistent functional bacteria of AS,although not numerically dominant,accounted for 96.24%of the total sequences related to nutrient turnover,suggesting the presence of a small number of longstanding and core functional bacteria in the AS ***,64%of the 5188 OTUs in AS,which accounted for 91.51%of the sequences,exhibited positive growth rates,which suggested that their apparent abundances were due to growth within the plant,not from *** together,these results demonstrated that the impact of influent populations on core AS communities was ***,this work provides quantitative insights into the impact of immigration,which is expected to advance our understanding of the AS community assembly.

关键词： Membrane bioreactor Activated sludge Core community Active population Immigration impact

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On Sums of a Prime and Four Prime Squares in Short Intervals

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Acta Mathematica Sinica,English Series 2008年第8期24卷 1291-1302页

作者： Guang Shi LU Xian meng meng Department of Mathematics Shandong University Ji'nan 250100 P. R. China Department of Statistics and Mathematics Shandong Finance Institute Ji'nan 250014 P. R. China

In this paper, we prove that each sufficiently large integer N ≠1（mod 3） can be written as N=p＋p1^2＋p2^2＋p3^2＋p4^2, with｜p-N/5｜≤U,｜pj-√N/5｜≤U,j=1,2,3,4,where U=N^2/20＋c and p,pj are primes.

关键词： exponential sums over primes circle method prime

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Design of structure and control system of semiconductor refrigeration box

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Chinese Journal of Chemical Engineering 2020年第11期28卷 2792-2798页

作者： meng Yu Zhiyun Zou Academy of Military Sciences Beijing 102205China

In order to create low temperature environment for the valve testing,a new type of semiconductor refrigeration box based on semiconductor refrigeration chip and programmable logic controller(PLC)control system is *** power of the semiconductor refrigeration chip is determined by calculating the heat dissipation characteristics of the semiconductor refrigeration *** natural convection heat dissipation with forced air cooling,the heat sink of semiconductor refrigeration chip is *** the control strategy,switch control is combined with an intelligent control *** single neuron optimization algorithm based on quadratic optimization is adopted to adjust and optimize the parameters of the proportional-integral-derivative(PID)controllers in real *** into account the limited hardware capabilities of the PLC,the Jacobian information in parameter adjustment is redesigned into a simplified form of *** actual test results of refrigeration box show good control performance.

关键词： Semiconductor refrigeration Structure design PLC Optimization algorithm

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