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Closed form solutions for free vibrations of rectangular Mindlin plates

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Acta Mechanica Sinica 2009年第5期25卷 689-698页

作者： yufeng xing bo liu The Solid Mechanics Research Center, Beihang University,100191 Beijing, China The Solid Mechanics Research Center Beihang University Beijing China

A new two-eigenfunctions theory, using the amplitude deflection and the generalized curvature as two fundamental eigenfunctions, is proposed for the free vibration solutions of a rectangular Mindlin plate. The three classical eigenvalue differential equations of a Mindlin plate are reformulated to arrive at two new eigenvalue differential equations for the proposed theory. The closed form eigensolutions, which are solved from the two differential equations by means of the method of separation of variables are identical with those via Kirchhoff plate theory for thin plate, and can be employed to predict frequencies for any combinations of simply supported and clamped edge conditions. The free edges can also be dealt with if the other pair of opposite edges are simply supported. Some of the solutions were not available before. The frequency parameters agree closely with the available ones through pb-2 Rayleigh-Ritz method for different aspect ratios and relative thickness of plate.

关键词： Mindlin plate Free vibration Closed form solution Separation of variable

Solution‑Processed Thin Film Transparent Photovoltaics:Present Challenges and Future Development

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Nano-Micro Letters 2025年第2期17卷 566-600页

作者： Tianle liu Munerah M.S.Almutairi Jie Ma Aisling Stewart Zhaohui xing Mengxia liu bo Hou Yuljae Cho UM-SJTU Joint Institute Shanghai Jiao Tong UniversityShanghai 200240People’s Republic of China School of Physics and Astronomy Cardiff UniversityCardiff CF243AAWalesUK Department of Electrical and Computer Engineering Yale UniversityNew HavenCT 06511USA Energy Sciences Institute Yale UniversityWest HavenCT 06516USA Future Photovoltaics Research Center Global Institute of Future TechnologyShanghai Jiao Tong UniversityShanghai 200240People’s Republic of China

Electrical energy is essential for modern society to sustain economic *** soaring demand for the electrical energy,together with an awareness of the environmental impact of fossil fuels,has been driving a shift towards the utilization of solar ***,traditional solar energy solutions often require extensive spaces for a panel installation,limiting their practicality in a dense urban *** overcome the spatial constraint,researchers have developed transparent photovoltaics(TPV),enabling windows and facades in vehicles and buildings to generate electric *** TPV advancements are focused on improving both transparency and power output to rival commercially available silicon solar *** this review,we first briefly introduce wavelength-and non-wavelengthselective strategies to achieve *** of merit and theoretical limits of TPVs are discussed to comprehensively understand the status of current TPV *** we highlight recent progress in different types of TPVs,with a particular focus on solution-processed thin-film photovoltaics(PVs),including colloidal quantum dot PVs,metal halide perovskite PVs and organic *** applications of TPVs are also reviewed,with emphasis on agrivoltaics,smart windows and ***,current challenges and future opportunities in TPV research are pointed out.

关键词： Transparent semiconductors Solution-processable transparent solar cell Emerging solar cell materials Buildingintegrated photovoltaics

Deep learning-based software engineering: progress,challenges, and opportunities

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Science China(Information Sciences) 2025年第1期68卷 57-144页

作者： Xiangping CHEN xing HU Yuan HUANG He JIANG Weixing JI Yanjie JIANG Yanyan JIANG bo liu Hui liu Xiaochen LI Xiaoli LIAN Guozhu MENG Xin PENG Hailong SUN Lin SHI bo WANG Chong WANG Jiayi WANG Tiantian WANG Jifeng XUAN Xin XIA Yibiao YANG Yixin YANG Li ZHANG Yuming ZHOU Lu ZHANG School of Journalism and Communication Sun Yat-sen University School of Software Technology Zhejiang University School of Software Engineering Sun Yat-sen University School of Software Dalian University of Technology School of Computer Science and Technology Beijing Institute of Technology Key Laboratory of High Confidence Software Technologies (Peking University) Ministry of EducationSchool of Computer Science Peking University State Key Laboratory for Novel Software Technology Nanjing University School of Computer Science and Engineering Beihang University Institute of Information Engineering Chinese Academy of Sciences School of Computer Science Fudan University State Key Laboratory of Complex & Critical Software Environment (CCSE) School of Software Beihang University School of Computer and Information Technology Beijing Jiaotong University School of Computer Science and Technology Harbin Institute of Technology School of Computer Science Wuhan University Huawei Technologies

Researchers have recently achieved significant advances in deep learning techniques, which in turn has substantially advanced other research disciplines, such as natural language processing, image processing, speech recognition, and software engineering. Various deep learning techniques have been successfully employed to facilitate software engineering tasks, including code generation, software refactoring, and fault localization. Many studies have also been presented in top conferences and journals, demonstrating the applications of deep learning techniques in resolving various software engineering tasks. However,although several surveys have provided overall pictures of the application of deep learning techniques in software engineering,they focus more on learning techniques, that is, what kind of deep learning techniques are employed and how deep models are trained or fine-tuned for software engineering tasks. We still lack surveys explaining the advances of subareas in software engineering driven by deep learning techniques, as well as challenges and opportunities in each subarea. To this end, in this study, we present the first task-oriented survey on deep learning-based software engineering. It covers twelve major software engineering subareas significantly impacted by deep learning techniques. Such subareas spread out through the whole lifecycle of software development and maintenance, including requirements engineering, software development, testing, maintenance, and developer collaboration. As we believe that deep learning may provide an opportunity to revolutionize the whole discipline of software engineering, providing one survey covering as many subareas as possible in software engineering can help future research push forward the frontier of deep learning-based software engineering more systematically. For each of the selected subareas,we highlight the major advances achieved by applying deep learning techniques with pointers to the available datasets i

关键词： deep learning software engineering software benchmark software artifact representation survey

C^1 conforming quadrilateral finite elements with complete secondorder derivatives on vertices and its application to Kirchhoff plates

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Science China(Technological Sciences) 2020年第6期63卷 1066-1084页

作者： WU Yang xing yufeng liu bo Institute of Solid Mechanics Beihang UniversityBeijing 100191China

The classical problem of the construction of C^1 conforming single-patch quadrilateral finite elements has been solved in this investigation by using the blending function interpolation *** order to achieve the C^1 conformity on the interfaces of quadrilateral elements,complete second-order derivatives are used at the element vertices,and the information of geometrical mapping is also considered into the construction of shape *** is found that the shape functions and the polynomial spaces of the present elements vary with element ***,the developed quadrilateral elements are at least third order for general quadrilateral shapes and fifth order for rectangular ***,very fast convergence can be achieved.A promising feature of the present elements is that they can be used in cooperation with those high-precision rectangular and triangular *** the present elements are over conforming on element vertices,an approach for handling problems of material discontinuity is also *** examples of Kirchhoff plates are employed to demonstrate the computational performance of the present elements.

关键词： finite element method quadrilateral elements C^1 conforming Kirchhoff plates

EXACT SOLUTIONS FOR FREE IN-PLANE VIBRATIONS OF RECTANGULAR PLATES

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Acta Mechanica Solida Sinica 2011年第6期24卷 556-567页

作者： bo liu yufeng xing The Solid Mechanics Research Center Beijing University of Aeronautics and Astronautics Beijing 100191 China

All possible exact solutions are successfully obtained in terms of 10 sets of distinct eigensolutions for the free in-plane vibration of isotropic rectangular plates. The plates have simply supported condition at two opposite edges and any combination of classical boundary conditions at the other two edges. The exact solutions are validated through both mathematical proof and comparisons with the solutions of differential quadrature method. Some unusual phenomena are revealed in free in-plane vibrations of rectangular plates due to one of the eigenvalues being zero. This work constitutes an improved version of very recent corresponding work by the same authors lint. J. Mech. Sci., 2009, 51： 246-255]. both the solution forms and solving procedures in the previous work are substantially simplified. Some new results are also given, which are useful for validation purpose in future.

关键词： rectangular plate in-pane free vibration frequency mode shape exact solution

Accurate closed-form eigensolutions of three-dimensional panel flutter with arbitrary homogeneous boundary conditions

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Chinese Journal of Aeronautics 2023年第1期36卷 266-289页

作者： Qiaozhen SUN yufeng xing bo liu bocheng ZHANG Zekun WANG COMAC Beijing Aircraft Technology Research Institute Beijing 102211China Institute of Solid Mechanics Beihang UniversityBeijing 100191China

Highly accurate closed-form eigensolutions for flutter of three-dimensional(3D)panel with arbitrary combinations of simply supported(S),glide(G),clamped(C)and free(F)boundary conditions(BCs),such as cantilever panels,are achieved according to the linear thin plate theory and the first-order piston theory as well as the complex modal analysis,and all solutions are in a simple and explicit *** iterative Separation-of-Variable(iSOV)method proposed by the pre-sent authors is employed to obtain the highly accurate *** flutter mechanism is studied with the benefit of eigenvalue properties from mathematical *** effects of boundary conditions,chord-thickness ratios,aerodynamic damping,aspect ratios and in-plane loads on flut-ter properties are *** results are compared with those of Kantorovich method and Galerkin method,and also coincide well with analytical solutions in literature,verifying the accu-racy of the present closed-form *** is revealed that,(A)the flutter characteristics are domi-nated by the cross section properties of panels in the direction of stream flow;(B)two types of flutter,called coupled-mode flutter and zero-frequency flutter which includes zero-frequency single-mode flutter and buckling,are observed;(C)boundary conditions and in-plane loads can affect both flutter boundary and flutter type;(D)the flutter behavior of 3D panel is similar to that of the two-dimensional(2D)panel if the aspect ratio is up to a certain value;(E)four to six modes should be used in the Galerkin method for accurate eigensolutions,and the results converge to that of Kantorovich method which uses the same mode functions in the direction perpendicular to the stream *** present analysis method can be used as a reference for other stability issues characterized by complex eigenvalues,and the highly closed-form solutions are useful in parameter designs and can also be taken as benchmarks for the validation of numerical methods.

关键词： Analytical Closed-form Eigenvalues Flutter Three-dimensional

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利用mtDNA信息分析陶寺古牛的起源驯化

农业生物技术学报 2025年第1期33卷 92-103页

作者：张兴杨柳侯凌云凌飞向海赵兴波华南理工大学生物科学与工程学院佛山大学动物科技学院/广东省动物分子设计与精准育种重点实验室中国农业大学动物科学技术学院/畜禽生物育种全国重点实验室

作为最重要的家畜之一，普通牛（bos taurus）在中国的起源和传播模式受到广泛关注。本研究收集了来自黄河中游3个考古遗址的9个古代牛遗骸，提取古DNA进行PCR测序和系统发生分析，以探索中国家养牛的起源和传播。经2轮PCR实验获得4个... 详细信息

作为最重要的家畜之一，普通牛（bos taurus）在中国的起源和传播模式受到广泛关注。本研究收集了来自黄河中游3个考古遗址的9个古代牛遗骸，提取古DNA进行PCR测序和系统发生分析，以探索中国家养牛的起源和传播。经2轮PCR实验获得4个陶寺（距今4100年前）古牛527 bp的线粒体DNA（mitochondrial DNA, mtDNA）序列。单倍型划分结果显示，陶寺古牛存在4种单倍型，都属于家养普通牛T3和T4单倍群，证实中国普通牛起源于近东地区，4 100年前就已经被华北人群利用。此外，陶寺遗址丰富的单倍型数量提示陶寺遗址古代牛群体具有较高的母系遗传多样性。群体间遗传分化指数FST（Fstatistics）分析和Median-Joining网络图表明，中国古代牛与现代东亚(FST=0.0164)及中国普通牛(FST=0.0066)均有密切的遗传关系，提示陶寺遗址古代牛群体可能是现代东亚和中国普通牛的重要母系祖先群体之一。本研究为解析我国的家牛起源和传播提供了分子遗传证据。

关键词：古代DNA 陶寺遗址普通牛起源

A Random Fusion of Mix 3D and Polar Mix to Improve Semantic Segmentation Performance in 3D Lidar Point Cloud

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Computer Modeling in Engineering & Sciences 2024年第7期140卷 845-862页

作者： bo liu Li Feng yufeng Chen School of Computer Science and Engineering Macao University of Science and TechnologyMacao999078China School of Computer Science and Artificial Intelligence Chaohu UniversityChaohu238000China Institute of Vehicle Information Control and Network Technology Hubei University of Automotive TechnologyShiyan442002China

This paper focuses on the effective utilization of data augmentation techniques for 3Dlidar point clouds to enhance the performance of neural network *** point clouds,which represent spatial information through a collection of 3D coordinates,have found wide-ranging *** augmentation has emerged as a potent solution to the challenges posed by limited labeled data and the need to enhance model generalization *** of the existing research is devoted to crafting novel data augmentation methods specifically for 3D lidar point ***,there has been a lack of focus on making the most of the numerous existing augmentation *** this deficiency,this research investigates the possibility of combining two fundamental data augmentation *** paper introduces PolarMix andMix3D,two commonly employed augmentation techniques,and presents a new approach,named *** of using a fixed or predetermined combination of augmentation methods,RandomFusion randomly chooses one method from a pool of options for each instance or *** innovative data augmentation technique randomly augments each point in the point cloud with either PolarMix or *** crux of this strategy is the random choice between PolarMix and Mix3Dfor the augmentation of each point within the point cloud data *** results of the experiments conducted validate the efficacy of the RandomFusion strategy in enhancing the performance of neural network models for 3D lidar point cloud semantic segmentation *** is achieved without compromising computational *** examining the potential of merging different augmentation techniques,the research contributes significantly to a more comprehensive understanding of how to utilize existing augmentation methods for 3D lidar point *** data augmentation technique offers a simple yet effective method to leverage the diversity of augmentation techniques and boost the ro

关键词： 3D lidar point cloud data augmentation RandomFusion semantic segmentation

Distribution prediction of moisture content of dead fuel on the forest floor of Maoershan national forest, China using a LoRa wireless network

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Journal of Forestry Research 2022年第3期33卷 899-909页

作者： bo Peng Jiawei Zhang Jian xing Jiuqing liu Northeast Forestry University Harbin150040People’s Republic of China

The moisture content of dead forest fuel is an important indicator of risk levels of forest fires and prediction of fire spread. Moisture distribution is important to determine wild fire rating. However, it is often difficult to predict moisture distribution because of a complex terrain, changeable environments and low cover of commercial communication signals inside the forest. This study proposes a moisture content prediction system composed of environmental data collected using a long range radio frequency band 433 MHz wireless sensor network and data processing for moisture prediction based on a BP (back-propagation) neural network. In the fall of 2019, twenty nodes for the collection of environmental data were placed in four forest stands of Maoershan National Forest for a month;7440 sets of data including temperature, humidity, wind speed and air pressure were obtained. Half the data were used as a training set, the other as a testing set for a BP neural network. The results show that the average absolute error between the predicted value and the real value of moisture content of fuels of Larix gmelini, Betula platyphylla, Juglans mandshurica, and Quercus mongolica stands was 0.94%, 0.21%, 0.86%, 0.97%, respectively. The prediction accuracy was relatively high. The proposed distributed moisture content prediction method has the advantages of wide coverage and good real-time performance;at the same time, it is not limited by commercial signals and so it is especially suitable for forest fire prediction in remote mountainous areas.

关键词： Distributed moisture content prediction Dead fuel BP neural network