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FREE VIBRATION ANALYSIS OF LATTICE SANDWICH BEAMS UNDER SEVERAL TYPICAL BOUNDARY CONDITIONS

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Acta Mechanica Solida Sinica 2013年第5期26卷 458-467页

作者： Jia lou bing Wang Li Ma Linzhi Wu Center for Composite Materials and Structures Harbin Institute of Technology

Free vibration problems of lattice sandwich beams under several typical boundary conditions are investigated in the present paper. The lattice sandwich beam is transformed to an equivalent homogeneous three-layered sandwich beam. Unlike the traditional analytical model in which the rotation angles of the face sheets and the core are assumed the same, different rotation angles are considered in this paper to characterize the real response of sandwich beams. The analytical solutions of the natural frequencies for several typical boundary conditions are obtained. The effects of material properties and geometric parameters on the natural frequencies are also investigated.

关键词： vibration composites lattice materials beam analytical method

Noise Reduction of an Axial Piston Pump by Valve Plate Optimization

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Chinese Journal of Mechanical Engineering 2018年第3期31卷 85-100页

作者： Shao-gan Ye Jun-Hui Zhang bing Xu State Key Laboratory of Fluid Power and Mechatronics Systems Zhejiang University Ocean College Zhejiang University

Current researches mainly focus on the investigations of the valve plate utilizing pressure relief grooves. However,air?release and cavitation can occur near the grooves. The valve plate utilizing damping holes show excellent perfor?mance in avoiding air?release and cavitation. This study aims to reduce the noise emitted from an axial piston pump using a novel valve plate utilizing damping holes. A dynamic pump model is developed,in which the fluid properties are carefully modeled to capture the phenomena of air release and cavitation. The causes of di erent noise sources are investigated using the model. A comprehensive parametric analysis is conducted to enhance the understanding of the e ects of the valve plate parameters on the noise sources. A multi?objective genetic algorithm optimization method is proposed to optimize the parameters of valve plate. The amplitudes of the swash plate moment and flow rates in the inlet and outlet ports are defined as the objective functions. The pressure overshoot and undershoot in the piston chamber are limited by properly constraining the highest and lowest pressure values. A comparison of the various noise sources between the original and optimized designs over a wide range of pressure levels shows that the noise sources are reduced at high pressures. The results of the sound pressure level measurements show that the optimized valve plate reduces the noise level by 1.6 d B(A) at the rated working condition. The proposed method is e ective in reducing the noise of axial piston pumps and contributes to the development of quieter axial piston machines.

关键词： Axial piston pump Noise reduction Fluid?borne noise Structure?borne noise Parametric analysis Multi?objective optimization

Bipartite double cover and perfect 2-matching covered graph with its algorithm

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Frontiers of Mathematics in China 2015年第3期10卷 621-634页

作者： Zhiyong gan Dingjun lou Zanbo ZHANG Xuelian WEN Department of Computer Science Sun Yat-sen University Guangzhou 510275 China Department of Computer Engineering Guangdong Industry Technical College Guangzhou 510300 China School of Economics and Management South China Normal University Guangzhou 510006 China

Let B（G） denote the bipartite double cover of a non-bipartite graph G with v ≥ 2 vertices and s edges. We prove that G is a perfect 2-matching covered graph if and only if B（G） is a 1-extendable graph. Furthermore, we prove that B（G） is a minimally l-extendable graph if and only if G is a minimally perfect 2-matching covered graph and for each e = xy ∈ E（G）, there is an independent set S in G such that ｜ГG（S）｜ = ｜S｜＋ 1, x ∈ S and ｜ГG-xy（S）｜ = ｜S｜ Then, we construct a digraph D from B（G） or G and show that D is a strongly connected digraph if and only if G is a perfect 2-matching covered graph. So we design an algorithm in O（x√vε） time that determines whether G is a perfect 2-matching covered graph or not.

关键词： Bipartite double cover perfect 2-matching covered graph 1-extendable graph minimally perfect 2-matching covered graph minimally 1-extendable graph algorithm

Mechanical Properties Study of Reinforced Thermoplastic Pipes Under A Tensile Load

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China Ocean Engineering 2020年第6期34卷 806-816页

作者： WANG Yang-yang lou Min TONG bing WANG Sen School of Petroleum Engineering China University of Petroleum(East China)Qingdao 266580China Key Laboratory of Unconventional Oil&Gas Development(China University of Petroleum(East China)) Ministry of EducationQingdao 266580China Hoisting Machinery Business Division Xuzhou Construction Machinery Group(XCMG)Xuzhou 221000China Weihai Nacheon Pipeline Co. Ltd.Weihai 264400China

This paper presents a study on the tensile properties of reinforced thermoplastic pipes(RTPs). A mechanical model of RTPs with an arbitrary number of reinforced layers under tensile action is constructed by combining the constitutive relationship of elastoplastic materials with the continuous displacement condition. On this basis, the effects of various parameters such as the winding angle, the number of structurally reinforced layers, and the inner polyethylene(PE) liner thickness on the tensile properties of the RTPs were analyzed, and a tensile test was carried out for validation. The results showed that the winding angle of the structurally reinforced layers was the main factor affecting an RTP's tensile performance— decreases in the winding angle significantly improved its tensile ability,especially the longitudinal strength. With ±45° as the demarcation point, the winding angle smaller than ±45° will result in higher strength in longitudinal direction, and the lifting effect on RTP's mechanical properties of the increasing number of reinforcement layers was better than that of the increasing thickness of the lining layer;when the winding angle was larger than ±45°, the opposite results were obtained. The fibre load was more sensitive to the winding angle than the PE load.

关键词： reinforced thermoplastic pipes tensile properties winding angle polyethylene

Wind-induced internal pressure response for structure with single windward opening and background leakage

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2008年第3期9卷 313-321页

作者： Shi-ce YU Wen-juan lou bing-nan SUN College of Civil Engineering and Architecture Zhejiang University Hangzhou 310027 China Department of Architecture Engineering Ningbo College of Technology Zhejiang University Ningbo 315100 China

Theoretical analysis and wind tunnel tests were carried out to study wind-induced intemal pressure response for the structure with single windward opening and background leakage. Its goveming differential equation was derived by the Bemoulli equation in an unsteady-isentropic form. Numerical examples were provided to study the additive damping caused by background leakage in laminar and turbulent flow, and the influence of background leakage on fluctuating internal pressure response was quantized. A series of models for low-rise building with various opening ratios and background leakage were designed and wind tunnel tests were conducted. It is shown that the fluctuating intemal pressure reduces when the background leakage are considered and that the effect of background leakage can be predicted accurately by the governing differential equation deduced in this paper.

关键词： Single windward opening Internal pressure Background leakage Governing equation Time-history analysis

Pyogenic discitis with an epidural abscess after cervical analgesic discography:A case report

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World Journal of Clinical Cases 2020年第11期8卷 2318-2324页

作者： bing Wu Xin He Bao-gan Peng Department of Spinal Surgery the Third Medical CenterPLA General HospitalBeijing 100039China Department of Orthopedics the First Hospital of QiqiharQiqihar 161000Heilongjiang ProvinceChina

BACKGROUND Chronic neck pain is a common clinical *** has long been considered that degenerative cervical disc is an important source of chronic neck *** the clinic,cervical discography is thought to be a useful and safe method to distinguish aging discs from pathological discs,and the probability of complications caused by it is really ***,once complication occurs,it is likely to cause fatal consequences to ***,accurate judgment and effective treatment are *** SUMMARY A 45-year-old female was admitted to the department with a 5-year history of severe neck pain,dizziness,and *** order to find the diseased disc,analgesic discography was performed on C4/5 and 6/7 discs ***,Discitis with an epidural abscess was caused during the *** the help of magnetic resonance imaging,an accurate diagnosis was made and an urgent anterior cervical operation was given *** patient ultimately recovered *** Discitis with epidural abscess is a rare complication after cervical discography,which needs accurate diagnosis and effective antibiotic treatment.

关键词： Discography Discitis Epidural abscess Diagnosis Treatment Magnetic resonance imaging

VPFL:A verifiable privacy-preserving federated learning scheme for edge computing systems

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Digital Communications and Networks 2023年第4期9卷 981-989页

作者： Jiale Zhang Yue Liu Di Wu Shuai lou bing Chen Shui Yu School of Information Engineering Yangzhou UniversityYangzhou225009China Water Conservancy and Civil Engineering College Inner Mongolia Agricultural UniversityHohhot010018China Deakin Blockchain Innovation Lab School of Information TechnologyDeakin UniversityMelbourneVIC3125Australia College of Computer Science and Technology Nanjing University of Aeronautics and AstronauticsNanjing211106China School of Computer Science University of Technology SydneySydney2007Australia

Federated learning for edge computing is a promising solution in the data booming era,which leverages the computation ability of each edge device to train local models and only shares the model gradients to the central ***,the frequently transmitted local gradients could also leak the participants’private *** protect the privacy of local training data,lots of cryptographic-based Privacy-Preserving Federated Learning(PPFL)schemes have been ***,due to the constrained resource nature of mobile devices and complex cryptographic operations,traditional PPFL schemes fail to provide efficient data confidentiality and lightweight integrity verification *** tackle this problem,we propose a Verifiable Privacypreserving Federated Learning scheme(VPFL)for edge computing systems to prevent local gradients from leaking over the transmission ***,we combine the Distributed Selective Stochastic Gradient Descent(DSSGD)method with Paillier homomorphic cryptosystem to achieve the distributed encryption functionality,so as to reduce the computation cost of the complex ***,we further present an online/offline signature method to realize the lightweight gradients integrity verification,where the offline part can be securely outsourced to the edge *** security analysis demonstrates the proposed VPFL can achieve data confidentiality,authentication,and *** last,we evaluate both communication overhead and computation cost of the proposed VPFL scheme,the experimental results have shown VPFL has low computation costs and communication overheads while maintaining high training accuracy.

关键词： Federated learning Edge computing Privacy-preserving Verifiable aggregation Homomorphic cryptosystem

Environmental impacts of a large-scale incinerator with mixed MSW of high water content from a LCA perspective

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Journal of Environmental Sciences 2015年第4期27卷 173-179页

作者： Ziyang lou Bernd Bilitewski Nanwen Zhu Xiaoli Chai bing Li Youcai Zhao School of Environmental Science and Engineering Shanghai Jiaotong University Institute for Waste Management and Contaminated Sites Treatment TU Dresden Faculty of Forestry Geo and Hydro Sciences State Key Laboratory of Pollution Control and Resource Reuse School of Environmental Science and Engineering Tongji University

Large-scale incinerators are applied widely as a result of the heavy burden of municipal solid waste（MSW） generated, while strong opposition is arising from the public living nearby. A large-scale working incineration plant of 1500 ton/day was chosen for evaluation using life cycle assessment. It was found that the corresponding human toxicity impacts via soil（HTs）, human toxicity impacts via water（HTw） and human toxicity impacts via air（HTa）categories are 0.213, 2.171, and 0.012 personal equivalents（PE）, and global warming（GW100）and nutrient enrichment（NE） impacts are 0.002 and 0.001 PE per ton of waste burned for this plant. Heavy metals in flue gas, such as Hg and Pb, are the two dominant contributors to the toxicity impact categories, and energy recovery could reduce the GW100 and NE greatly. The corresponding HTs, HTw and HTa decrease to 0.087, 0.911 and 0.008 PE, and GW100 turns into savings of- 0.007 PE due to the increase of the heating value from 3935 to5811 k J/kg, if a trommel screener of 40 mm mesh size is used to pre-separate MSW. MSW sorting and the reduction of water content by physical pressure might be two promising pre-treatment methods to improve the combustion performance, and the application of stricter standards for leachate discharge and the flue gas purification process are two critical factors for improvement of the environmental profile identified in this work.

关键词： Large scale incinerator Life cycle assessment Environmental impact MSW Sorting system China

Chemically recyclable polyesters from CO_(2),H_(2),and 1,3-butadiene

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The Innovation 2022年第2期3卷 119-125页

作者： Yongjia lou Luyan Xu Ninglin gan Yunyan Sun Bo-Lin Lin School of Physical Science and Technology ShanghaiTech UniversityShanghai 201210China

Chemically recyclable solid polymeric materials with commercializable properties only using CO_(2)and inexpensive bulk chemicals as chemical feedstock can open a brand-new avenue to economically viable,large-scale fixation of CO_(2)over a long period of *** previous great advancements,development of such a kind of CO_(2)-based polymers remains a longterm unsolved research challenge of great significance.

关键词： polyester butadiene Chemically