检索结果-南通市图书馆

OUT-OF-PLANE COMPRESSIVE PROPERTIES OF HEXAGONAL PAPER HONEYCOMBS

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Mechanical Engineering 2007年第2期20卷 115-119页

作者： wang Dongmei wang zhiwei Media and Communication School Shenzhen Polytechnic Shenzhen 518055 China Modem Mechanical and Packaging Institute Southern Yangtze University Wuxi 214122 China Packaging Engineering Institute Jinan University Guangzhou 519070 China

The compressive behaviour of paper honeycombs is studied by means of an experimental analysis. Experiment results show how geometry aspects of hexagonal paper honeycombs, e.g. the height of paper honeycomb, the thickness and length of honeycomb cell-wall, the drawing ratio of hexagonal honeycomb, affect the compressive properties of the paper honeycombs. It is in good agreement with the theory model. The constraint factor K of the critical buckling stress is mainly determined by the length of honeycomb cell-wail. It can be described as K=1.54 for B type paper honeycombs and K=3.32 for D type paper honeycombs. The plateau stress is the power exponent function of the thickness to length ratio of honeycomb cell-wall, and the experiment results show that the constant is 13.2 and the power exponent is 1.77. The research results can be used to characterize and improve efficiently the compressive properties of paper honeycombs.

关键词： Paper honeycombs Compressive behaviour Geometry structure Constraint factor

Efficiently constructing collision-free regions of tool orientations for holder in five-axis machining of blisk

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2020年第10期33卷 2743-2756页

作者： zhiwei wang Xiaojun LIN Yaoyao SHI School of Mechanical Engineering Northwestern Polytechnical UniversityXi’anShaanxi 710072China

Blisks with the integral structure are key parts used in new jet engines to promote the performance of aircrafts,which also increases the complexity of tool orientation planning in the five-axis *** is an essential task to find the collision-free tool orientation when the tool holder is pushed deep into the channel of blisk to increase rigidity and reduce *** the radius of the holder varies with the height,the line-visibility is no longer applicable when constructing collision-free regions of tool *** this paper,a method of constructing collisionfree regions without interference checking is *** work of finding collision-free regions resorts to solving the local contact curves on the checking surfaces of *** it further transforms into searching the locally tangent points(named critical points)between the holder and *** a tracking-based algorithm is proposed to search the sample critical points on these local contact *** the corresponding critical vectors are also calculated ***,the safety allowance,discrete precision and acceptable deviation are introduced in the algorithm to ensure accuracy by controlling the angle between two adjacent critical vectors *** that,the searched critical vectors are mapped orderly to two-dimensional space and the collisionfree regions are *** method is finally verified and compared with a referenced *** results show that the proposed method can efficiently construct collision-free regions for holder under the given accuracy.

关键词： Blisk Collision-free region Five-axis Interference detection Machining Tool holder

Enhanced Privacy-Preserving WiFi Fingerprint Localization from CL Encryption

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Electronics 2024年第6期33卷 1435-1446页

作者： zhiwei wang Qiuchi ZHU Zhenqi ZHANG School of Computer Nanjing University of Posts and Telecommunications State Key Laboratory of Public Big Data Guizhou University Advanced Cryptography and System Security Key Laboratory of Sichuan Province Chengdu University of Information Engineering Key Laboratory of Computational Science and Application of Hainan Province Hainan Normal University

The WiFi fingerprint-based localization method is considered one of the most popular techniques for indoor localization. In INFOCOM'14, Li et al. proposed a wireless fidelity(WiFi) fingerprint localization system based on Paillier encryption, which is claimed to protect both client C 's location privacy and service provider S's database privacy. However, Yang et al. presented a practical data privacy attack in INFOCOM'18, which allows a polynomial time attacker to obtain S's database. We propose a novel WiFi fingerprint localization system based on CastagnosLaguillaumie(CL) encryption, which has a trustless setup and is efficient due to the excellent properties of CL encryption. To prevent Yang et al.'s attack, the system requires that S selects only the locations from its database that can receive the nonzero signals from all the available access points in C 's nonzero fingerprint in order to determine C's location. Security analysis shows that our scheme is secure under Li et al.'s threat model. Furthermore, to enhance the security level of privacy-preserving WiFi fingerprint localization scheme based on CL encryption, we propose a secure and efficient zero-knowledge proof protocol for the discrete logarithm relations in C's encrypted localization queries.

关键词： Location awareness Threat modeling Data privacy Protocols Databases Fingerprint recognition Trustless services Encryption Servers Wireless fidelity

Ozonation of aromatic monomer compounds in water: factors determining reaction outcomes

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Frontiers of Environmental Science & Engineering 2023年第5期17卷 13-25页

作者： Zhe wang Wenjuan Zhang zhiwei wang Jing Chang School of Environmental Science and Safety Engineering Tianjin University of TechnologyTianjin 300384China School of Environmental and Municipal Engineering Tianjin Key Laboratory of Aquatic Science and TechnologyTianjin Chengjian UniversityTianjin 300384China Tianjin Municipal Engineering Design&Research Institute Co. Ltd.Tianjin 300384China

For aromatic monomer compounds (AMCs), ozonation outcomes were usually predicted by the substituents of the benzene ring based on the electron inductive effect. However, the predicted results were occasionally unreliable for complex substituents, and other factors caused concern. In this study, p-chloronitrobenzene (p-CNB) and ibuprofen (IBP) were selected for ozonation. According to the electron inductive theory, p-CNB should be less oxidizable, but the opposite was true. The higher rates of p-CNB were due to various sources of assistance. First, the hydroxyl radical (•OH) contributed 90 % to p-CNB removal at pH 7.0, while its contribution to IBP removal was 50 %. Other contributions came from molecular O3 oxidation. Second, p-CNB achieved 40 % of the total organic carbon (TOC) removal and fewer by-product types and quantities, when compared to the results for IBP. Third, the oxidation of p-CNB started with hydroxyl substitution reactions on the benzene ring;then, the ring opened. However, IBP was initially oxidized mainly on the butane branched chain, with a chain-shortening process occurring before the ring opened. Finally, the degradation pathway of p-CNB was single and consumed fewer oxidants. However, both branches of IBP were attacked simultaneously, and three degradation pathways that relied on more oxidants were proposed. All of these factors were determinants of the rapid removal of p-CNB.

关键词： Ozonation Aromatic compound Oxidizing specie By-product Initial reaction position Degradation pathway

A Kahlerness criterion for real (1,1)-classes on projective manifolds through extendibility of singular potentials

在线全文

学校读者我要写书评

暂无评论

Science China Mathematics 2022年第9期65卷 1795-1802页

作者： Xiankui Meng zhiwei wang School of Science Beijing University of Posts and TelecommunicationsBeijing 100876China Laboratory of Mathematics and Complex Systems(Ministry of Education) School of Mathematical SciencesBeijing Normal UniversityBeijing 100875China

Let X be a projective manifold and let{θ}∈H 1,1(X,R)be a nonzero pseudo-effective(transcendental)class,where θ is a smooth closed real(1,1)-*** prove that if for any one-dimensional complex submanifold C⊂X and φ∈SPsh(C,θ|C)with a single analytic singularity at some point p∈C,there exists a function φ∈Psh(X,θ)such that φ|C=φ and φ is continuous at points of C∖{p},then{θ}is a Kahler class.

关键词： transcendental class quasi-psh function Kahler class

Characterizations of plurisubharmonic functions

在线全文

学校读者我要写书评

暂无评论

Science China Mathematics 2021年第9期64卷 1959-1970页

作者： Fusheng Deng Jiafu Ning zhiwei wang School of Mathematical Sciences University of Chinese Academy of SciencesBeijing100049China School of Mathematics and Statistics HNP-LAMA Central South UniversityChangsha410083China Laboratory of Mathematics and Complex Systems(Ministry of Education) School of Mathematical SciencesBeijing Normal UniversityBeijing100875China

We give characterizations of(quasi-)plurisubharmonic functions in terms of L^(p)-estimates of■and Lp-extensions of holomorphic functions.

关键词： plurisubharmonic function H?rmander’s L2-estimate Ohsawa-Takegoshi extension theorem characterization of plurisubharmonicity

A hybrid membrane process for simultaneous thickening and digestion of waste activated sludge

在线全文

学校读者我要写书评

暂无评论

Frontiers of Environmental Science & Engineering 2010年第3期4卷 272-279页

作者： zhiwei wang Qiaoying wang Zhichao WU Xinhua wang State Key Laboratory of Pollution Control and Resource Reuse School of Environmental Science and EngineeringTongji UniversityShanghai 200092China

A hybrid membrane process for simultaneous sludge thickening and digestion(MSTD)was *** one cycle(15 d)of operation under a hydraulic retention time of 1 d,the concentration of mixed liquor suspended solids(MLSS)continuously increased from about 4 g·L^(–1)to 34 g·L^(–1),and the mixed liquor volatile suspended solids(MLVSS)increased from about 3 g·L^(–1)to over 22 g·L^(–1).About 42%of the MLVSS and 39%of the MLSS reduction were *** thickening and digestion effects in the MSTD were further analyzed based on a mass balance *** results showed that biopolymers and cations of biomass were gradually released to the bulk solution during the *** was also found that the capillary suction time,colloidal chemical oxygen demand,soluble microbial products,viscosity,and MLSS had significant positive correlations with the membrane fouling rate,whereas extracellular polymeric substances,polysaccharides,and proteins extracted from biomass had negative impacts on membrane fouling.

关键词： membrane filtration sludge digestion sludge thickening waste activated sludge

Tuning the primary selective nanochannels of MOF thin-film nanocomposite nanofiltration membranes for efficient removal of hydrophobic endocrine disrupting compounds

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Frontiers of Environmental Science & Engineering 2022年第4期16卷 1-13页

作者： Ruobin Dai Hongyi Han Yuting Zhu Xi wang zhiwei wang State Key Laboratory of Pollution Control and Resource Reuse Shanghai Institute of Pollution Control and Ecological SecuritySchool of Environmental Science and EngineeringTongji UniversityShanghai 200092China Tongji Architectural Design(Group)Co. Ltd.Environmental Engineering BranchShanghai 200092China

Metal organic framework(MOF)incorporated thin-film nanocomposite(TFN)membranes have the potential to enhance the removal of endocrine disrupting compounds(EDCs).In MOF-TFN membranes,water transport nanochannels include(i)pores of polyamide layer,(ii)pores in MOFs and(iii)channels around MOFs(polyamide-MOF interface).However,information on how to tune the nanochannels to enhance EDCs rejection is scarce,impeding the refinement of TFN membranes toward efficient removal of *** this study,by changing the polyamide properties,the water transport nanochannels could be confined primarily in pores of MOFs when the polyamide layer became ***,the improved rejection of EDCs was dependent on the water transport channels of the TFN *** low monomer concentration(i.e.,loose polyamide structure),the hydrophilic nanochannels of MIL-101(Cr)in the polyamide layer could not dominate the membrane separation performance,and hence the extent of improvement in EDCs rejection was relatively *** contrast,at high monomer concentration(i.e.,dense polyamide structure),the hydrophilic nanochannels of MIL-101(Cr)were responsible for the selective removal of hydrophobic EDCs,demonstrating that the manipulation of water transport nanochannels in the TFN membrane could successfully overcome the permeability and EDCs rejection *** results highlight the potential of tuning primary selective nanochannels of MOF-TFN membranes for the efficient removal of EDCs.

关键词： Porous metal organic framework Thin-film nanocomposite membrane Primary selective nanochannels Nanofiltration Endocrine disrupting compounds

Implications of Stahl's Theorems to Holomorphic Embedding Part I: Theoretical Convergence

在线全文

学校读者我要写书评

暂无评论

CSEE Journal of Power and Energy Systems 2021年第4期7卷 761-772页

作者： Songyan Li Daniel Tylavsky Di Shi zhiwei wang School of Electrical Computer and Energy Engineering in Arizona State University TempeAZ 85287USA AINERGY LLC Santa ClaraCA 95051 State Grid Jiangsu Electric Power Company Nanjing 210024China

What is known as StahPs Theorem in power engineering circles is used to justify a convergence guarantee of the Holomorphic Embedding Method(HEM)as it applies to powerflow(PF)*** this two-part paper,we examine in more detail the implications of Stahl's theorems to both theoretical and numerical convergence for a wider range of problems to which these theorems are now being *** show that the difference between StahPs extremal domain and the function's domain is responsible for theoretical nonconvergence and that the fundamental cause of numerical nonconvergence is the magnitude of logarithmic capacity of the branch cut,a concept central to understanding *** introduce theorems using the necessary mathematical parlance and then translate the language to show its implications to convergence of nonlinear problems in general and specifically to the PF *** show that,among other possibilities,the existence of Chebotarev points,which are embedding specific,are a possible theoretical impediment to convergence・The theoretical foundation of Part I is necessary for understanding the numerical behavior of HEM discussed in Part II.

关键词： Analytic continuation holomorphic embedding method power flow Pade approximants HEM Stahl's theorems