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Experimental Study on Diesel Spray and Flame Asymmetry Characteristics of Dual-Orifice Nozzles for a Medium-Speed Engine

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Journal of Thermal Science 2025年第1期 303-322页

作者： JU Dehao LIU Rui ZHENG Liang DENG Jiahui zhang wenzheng HUO Jinlu HUANG Li Shanghai Marine Diesel Engine Research Institute National Key Laboratory of Marine Engine Science and Technology Key Laboratory for Power Machinery and Engineering Ministry of EducationShanghai Jiao Tong University

The asymmetry of the multi-orifice spray will cause uneven heat load of the marine diesel engine,thereby affecting its working performance and service ***,an in-depth understanding of the spray and flame characteristics of multi-orifice nozzles will guide the optimization of the nozzle structure,needle design and diesel atomization and combustion *** this reason,four groups of dual-orifice nozzles with different hole diameters(0.1-0.55 mm) and mass flow rates covering the typical marine medium-speed diesel injections are designed and customized,and the constant volume chamber(CVC) with high temperature and pressure is used to simulate the actual in-cylinder working conditions of the diesel engine for the spray visualization *** study the asymmetry of the fuel sprays discharged from a diesel injector,the multi-orifice nozzle is simplified as a dual-orifice nozzle in this *** with X-ray Computed Tomography(CT) imaging technology,the influences of the nozzle internal structure on the spray and flame asymmetry are studied in the constructed supercritical *** is found that the asymmetry of the inlet angle and the equivalent length-diameter ratio is positively correlated with the inconsistency of the dual *** an increase in the injection pressure and nozzle diameter,the asymmetry of the dual spray becomes more pronounced,resulting in greater disparities in the ignition delay times and ignition positions of the two ***,the increase in nozzle diameter also leads to combustion instability,resulting in a flame with a serrated *** the increase of ambient temperature,the proportion of liquid phase in the jet decreases and the relative density of spray front decreases.

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Identification of Secondary Dislocations by Singular Value Decomposition of the Nye Tensor

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Acta Metallurgica Sinica(English Letters) 2014年第6期27卷 1078-1082页

作者： Fuzhi Dai wenzheng zhang Key Laboratory of Advanced Materials (MOE) School of Materials Science and Engineering Tsinghua University

Recently, we proposed the use of singular values and singular vectors of the Nye tensor to specify the features of dislocations. To further validate the method in identifying dislocations, the algorithm is applied to detect secondary dislocations in this paper. Different from the perfect and partial dislocations where the reference state is a single crystal, the reference state for detecting secondary dislocations should be a bi-crystal in a coincident coherent state. It is demonstrated that the secondary dislocations in an interface can be correctly identified when the reference state is appropriately selected.

关键词： Nye tensor Singular value decomposition Secondary dislocation

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A systematic analysis of good matching sites between two lattices

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Science China(Technological Sciences) 2012年第5期55卷 1343-1352页

作者： YANG XiaoPeng zhang wenzheng Laboratory of Advanced Materials Department of Materials Science and EngineeringTsinghua UniversityBeijing 100084China

The geometrical matching/mismatching of lattices overlapped in 1, 2 and 3 dimensions have been analyzed systematically by variation of lattice misfit in a large range, far beyond the limits for semicoherent interfaces. In order to evaluate the degree of matching, the density of good matching site （GMS） between two lattices is calculated. The analysis shows that the GMS density remains approximately constant, irrespectively to the degree of lattice misfit. This constant, defined as the average GMS density, decreases exponentially with the increasing dimension of misfit. Typically, for 6 = 15%, the average GMS densities are approximately 30%, 7%, and 1.4% for 1D, 2D, and 3D lattice misfits, respectively. The GMS density deviates significantly if a CSL of small X can be defined. The relationship between the GMS distribution and O-lattice is investigated. It indicates that an abrupt increase in the GMS density in an interface parallel to a principal O-lattice plane is equivalent to a reduction of dimension of misfit. This shows the agreement between the selections of principal O-lattice planes as candidates of the preferred interfaces and the condition that interfaces with high GMS density are preferred.

关键词： good matching sites (GMS) O-lattice near-coincidence sites (NCS) structure ledge coincidence site lattice (CSL)

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Application of the O-line model to martensite crystallography

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Science China(Technological Sciences) 2012年第2期55卷 464-469页

作者： GU XinFu zhang wenzheng Laboratory of Advanced Materials Department of Materials Science and EngineeringTsinghua UniversityBeijing 100084China Grikin Advanced Materials Co. LtdBeijing 102200China

The O-line model is usually applied to precipitation *** application to investigation of martensite crystallography has received little *** this paper,the relationship between O-line model and the prism matching model for martensite crystallography is *** formulas in the O-line model are applicable to martensite *** solution of the habit plane corresponding to the minimum shape strain has been derived.A calculation example of {3 10 15}f martensite in a ferrous alloy is *** the results are in agreement with the former models for martensite crystallography,the advantage of O-line model is that it offers analytical solutions,facilitating further systematic investigations.

关键词： habit plane O-line model martensite crystallography PTMC

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Large-Amplitude Oscillations of Hyperelastic Cylindrical Membrane Under Thermal-Mechanical Fields

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Acta Mechanica Solida Sinica 2022年第2期35卷 303-315页

作者： wenzheng zhang Datian Niu Fengxia Zhao College of Science Dalian Minzu UniversityDalian 116600China Department of Information Engineering Qinhuangdao Vocational and Technical CollegeQinhuangdao 066100China

In this paper,the nonlinear dynamic behaviors of a hyperelastic cylindrical membrane composed of the incompressible Ogden material are examined,where the membrane is subjected to uniformly distributed radial periodic loads at the internal surface and surrounded by a thermal field.A second-order nonlinear differential equation describing the radially symmetric motion of the membrane is ***,the dynamic characteristics of the system are qualitatively analyzed in terms of different material parameter spaces and ambient ***,for a given constant load,the bifurcation phenomenon of equilibrium points is *** is shown that there exists a critical load,and the phase orbits may be the asymmetrie homoclinic orbits of the“oo”***,for the system with two centers and one saddle point,the dynamic behaviors of the system show softening phenomena at both centers,but the temperature has opposite effects on the stiffness of the *** a given periodically perturbed load superposed on the constant term,some complex dynamic behaviors such as quasiperiodic and chaotic oscillations are *** the Poincare section and the maximum Lyapunov characteristic exponent,it is found that the ambient temperature could lead to the irregularity and unpredictability of the nonlinear system,and also changes the threshold of chaos.

关键词： Cylindrical membrane Radial perturbed load Ambient temperature Bifurcation and chaos

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Threshold public key encryption scheme resilient against continual leakage without random oracles

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Frontiers of Computer Science 2013年第6期7卷 955-968页

作者： Xiujie zhang Chunxiang XU wenzheng zhang Wanpeng LI School of Computer Science and Engineering University of Electronic Science and Technology of China Chengdu 611731 China Science and Technology on Communication Security Laboratory The 30th Research Institute of China Electronics Technology Group Corporation Chengdu 610041 China

Threshold public key encryption allows a set of servers to decrypt a ciphertext if a given threshold of authorized servers cooperate. In the setting of threshold public key encryption, we consider the question of how to correctly decrypt a ciphertext where all servers continually leak information about their secret keys to an external attacker. Dodis et al. and Akavia et al. show two concrete schemes on how to store secrets on continually leaky servers. However, their construc- tions are only interactive between two servers. To achieve continual leakage security among more than two servers, we give the first threshold public key encryption scheme against adaptively chosen ciphertext attack in the continual leak- age model under three static assumptions. In our model, the servers update their keys individually and asynchronously, without any communication between two servers. Moreover, the update procedure is re-randomized and the randomness can leak as well.

关键词： leakage-resilient continual leakage Threshold Public Key Encryption adaptive chosen ciphertext security standard model

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A Distributed Self-Tallying Electronic Voting System Using the Smart Contract

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Chinese Journal of Electronics 2024年第4期33卷 1063-1076页

作者： Jingyu YAO Bo YANG Tao WANG wenzheng zhang School of Computer Science Shaanxi Normal University State Key Laboratory of Integrated Services Networks Xidian University Science and Technology on Communication Security Laboratory

For electronic voting(e-voting) with a trusted authority, the ballots may be discarded or tampered, so it is attractive to eliminate the dependence on the trusted party. An e-voting protocol, where the final voting result can be calculated by any entity, is known as self-tallying e-voting protocol. To the best of our knowledge, addressing both abortive issue and adaptive issue simultaneously is still an open problem in self-tallying e-voting *** Ethereum blockchain with cryptographic technologies, we present a decentralized self-tallying e-voting protocol. We solve the above problem efficiently by utilizing optimized Group Encryption Scheme and standard Exponential El Gamal Cryptosystem. We use zero-knowledge proof and homomorphic encryption to protect votes' secrecy and achieve self-tallying. All ballots can be verified by anyone and the final voting result can be calculated by any entity. In addition, using the paradigm of score voting and “1-out-of-k” proof, our e-voting system is suitable for a wide range of application scenarios. Experiments show that our protocol is more competitive and more suitable for large-scale voting.

关键词： Electronic voting systems Smart contracts Blockchains Cryptocurrency Electronic voting Homomorphic encryption Standards

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Dislocation-mediated migration of interphase boundaries

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Journal of Materials Science & Technology 2019年第11期35卷 2714-2726页

作者： Zhipeng Sun Fuzhi Dai Ben Xu wenzheng zhang School of Materials Science and Engineering Tsinghua UniversityBeijing 100084China Science and Technology of Advanced Functional Composite Laboratory Aerospace Research Institute of Materials and Processing TechnologyBeijing 100076China Key Laboratory of Advanced Materials(MOE) State Key Laboratory of New Ceramics and Fine ProcessingChina

Faceted interphase boundaries(IPBs)are commonly observed in lath-shaped precipitates in alloys consisting of simple face-centred cubic(fcc),body centred-cubic(bcc)or hexagonal closed packed(hcp)phases,which normally contain one or two sets of parallel *** influence of these dislocations on interface migration and possible accompanying long-range strain field remain *** elucidate this,we carried out atomistic simulations to investigate the dislocation-mediated migration processes of IPBs in a pure-iron *** results show that the migration of these IPBs is accompanied with the slip of interfacial dislocations,even in high-index slip planes,with two migration modes were observed:the first mode is the uniform migration mode that occurs only when all of the dislocations slip in a common slip plane.A shear-coupled interface migration was observed for this *** other interfaces propagate in the stick-slip migration mode that occurs when the dislocations glide on different slip planes,involving dislocation reaction or tangling.A quantitative relationship was established to link the atomic displacements with the dislocation structure,slip plane,and interface *** macroscopic shear deformation due to the effect of overall atomic displacement shows a good agreement with the results obtained based on the phenomenological theory of martensite *** findings have general implications for the understanding of phase transformations and the surface relief effect at the atomic scale.

关键词： Interphase boundary migration O-line interface Shear-coupled interface migration Dislocation gliding Atomic displacement

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FINITE DEFORMATION OF A CLASS OF RECTANGULAR RUBBER RINGS SUBJECTED TO END AXIAL LOADS

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Acta Mechanica Solida Sinica 2012年第2期25卷 144-151页

作者： wenzheng zhang Xuegang Yuan Hongwu zhang Jiusheng Ren State Key Laboratory of Structural Analysis for Industrial Equipment Department of Engineering MechanicsFaculty of Vehicle Engineering and MechanicDalian University of TechnologyDalian 116024China School of Science Dalian National UniversityDalian 116600China Shanghai Institute of Applied Mathematics and Mechanics Shanghai UniversityShanghai 200072China

The problem of finite deformation of an incompressible rectangular rubber ring with an internal rigid body, where the ring is subjected to equal axial loads at its two ends, is examined. A reasonable mathematical model is formulated by using the nonlinear field theory and the implicit analytical solutions are derived. Then numerical simulations are implemented to further illustrate the results and obtain some meaningful conclusions. The deformation of the lateral surface of the ring becomes larger with the increasing axial loads, the decreasing ratio of the inner and outer radii and the increasing height of the ring.

关键词： neo-Hookean material rectangular rubber ring axial load finite deformation implicit analytical solution

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New forward-secure signature schemes with untrusted update

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Frontiers of Computer Science 2013年第4期7卷 536-543页

作者： Wanpeng LI Chunxiang XU wenzheng zhang Shixiong ZHU Xiujie zhang School of Computer Science and Engineering University of Electronic Science and Technology of China Chengdu 611731 China Science and Technology on Communication Security Laboratory The 30th Research Institute of China Electronics Technology Group Corporation Chengdu 610041 China

In this paper, we present two forward-secure signature schemes （FSS） with untrusted update. Our constructions use ideas from the work of Abdalla et al. [1] and Kozlov and Reyzin [2] in their forward-secure digital signature schemes. Our schemes are proven to be forward-secure based on the hardness of factoring in the random oracle model. Both schemes use the same method to encrypt the private key and are more efficient than Libert scheme [3] without adding any burden to the original forward-secure schemes.

关键词： forward-secure digital signature untrusted update

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