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Load laws of composite lining in mountain tunnel model tests and numerical simulation validation

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Journal of Mountain Science 2023年第7期20卷 2041-2057页

作者： ZHOU Jian YANG Xin-an chu zheng Department of Civil Engineering Hangzhou City UniversityHangzhou 310015China Key Laboratory of Safe Construction and Intelligent Maintenance for Urban Shield Tunnels of Zhejiang Province Hangzhou City UniversityHangzhou 310015China The Key Laboratory of Road and Traffic Engineering Ministry of EducationTongji UniversityShanghai 201804China School of Information and Electrical Engineering Hangzhou City UniversityHangzhou 310015China

Currently,model tests are increasingly being used to simulate the construction of mountain tunnels,but the support structure of the model tests does not show the composite lining,and the force laws of the composite lining are not yet *** this research,the force variation of composite lining under three cases in model tests of deep-buried tunnels were carried out with the surrounding rock grade and installation time as the variation *** test results reveal that:(1)The suitable method to reduce the contact load between the secondary lining and primary support is to enhance the primary support in the soft and weak surrounding ***,for ClassⅢsurrounding rock and better quality of surrounding rock,the primary support can lag behind the excavation face a certain distance.(2)The axial forces of the bolts tend to rise with concentration of 0.4 kN-0.7 kN after the secondary lining was installed.(3)With or without two to three excavation cycles delayed,the load sharing ratio of the secondary lining of the Class III surrounding rock is less than 10%.Finally,the numerical simulation verifies the feasibility of the model tests.

关键词： Mountain tunnel Composite lining Surrounding rock grade Force variation Primary support Secondary lining

Differentially private SGD with random features

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Applied Mathematics(A Journal of Chinese Universities) 2024年第1期39卷 1-23页

作者： WANG Yi-guang GUO zheng-chu Polytechnic Institute of Zhejiang University Zhejiang UniversityHangzhou 310015China School of Mathematical Sciences Zhejiang UniversityHangzhou 310058China

In the realm of large-scale machine learning,it is crucial to explore methods for reducing computational complexity and memory demands while maintaining generalization ***,since the collected data may contain some sensitive information,it is also of great significance to study privacy-preserving machine learning *** paper focuses on the performance of the differentially private stochastic gradient descent(SGD)algorithm based on random *** begin,the algorithm maps the original data into a lowdimensional space,thereby avoiding the traditional kernel method for large-scale data storage ***,the algorithm iteratively optimizes parameters using the stochastic gradient descent ***,the output perturbation mechanism is employed to introduce random noise,ensuring algorithmic *** prove that the proposed algorithm satisfies the differential privacy while achieving fast convergence rates under some mild conditions.

关键词： learning theory differential privacy stochastic gradient descent random features reproducing kernel Hilbert spaces

Microscopic phase-field simulation of L1_2 and D0_(22) phases during the early precipitation process of Ni-Cr-Al alloys

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Journal of University of Science and Technology Beijing 2006年第5期13卷 429-434页

作者： Zhong chu zheng Chen Yongxin Wang Yanli Lu Yongsheng Li State Key Laboratory for Solidification Processing Northwestern Polytechnical University Xi＇an 710072 China

The influence of temperature on the precipitation mechanism and sequence of L 12 and D022 phases during the early precipitation process of a ***%Cr-14at%Al alloy was simulated based on the microscopic phase-field model. In the range from 873 to 1373 K, the precipitation mechanism transformed from spinodal decomposition to non-classic nucleation and growth; the incubation period prolonged gradually with increasing temperature. The volume fraction of L12 phases increased and that of D022 phases decreased. D022 phases disappeared at 1373 K, and finally single-phase L12 phases were formed.

关键词： Ni-Cr-AI alloys microscope phase-field model precipitation ordering parameter simulation

Microscopic Phase-field Simulation of Competition Mechanism Between Ll_2 and D0_(22) Structure in Ni-Cr-Al Alloy

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Journal of Materials Science & Technology 2006年第3期22卷 315-320页

作者： Zhong chu zheng CHEN Yongxin WANG Yanli LU Yongsheng LI State Key Lab of Solidification Processing Northwestern Polytechnical University Xi＇an 710072 China

Simulations are performed on temporal evolution of atom morphology and ordering parameters of Ni-14.5 Cr-16.5 Al alloy during early precipitation process at different temperatures based on microscopic phase-field theory; the relationship between precipitation sequence and mechanism of L12 and D022 structure and precipitation temperature are illuminated. The nonstoichiometric ordered L12 phases appear first with congruent ordering＋spinodal decomposition mechanism which is then followed by precipitation of D022 phases at ordering domain boundaries of L12 phases by spinodal decomposition mechanism at 1073 K and 1223 K. The nonstoichiometric L12 phases transform to stoichiometric ordering phases gradually. The incubation period of L12 and D022 phases is shorter at 1073 K than that 1223 K, and growth speed is higher at 1073 K. At 1373 K, L12 and D022 phases appear simultaneously by non-classical nucleation and growth mechanism. After that the particles of D022 phases diminish and disappear gradually; L12 phases grow and single L12 phases are remained at last.

关键词： Ni-Cr-Al Microscopic phase-field model Precipitation Ordering parameter Simulation

Intelligent Reflecting Surfaces Enabled Cognitive Internet of Things Based on Practical Pathloss Model

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China Communications 2020年第12期17卷 1-16页

作者： zheng chu Pei Xiao De Mi Hongzhi Chen Wanming Hao Institute for Communication Systems University of SurreyGuildford GU27XHUK School of Information Engineering Zhengzhou UniversityZhengzhou 450001China

In this paper,we aim to unlock the potential of intelligent reflecting surfaces(IRSs)in cognitive internet of things(loT).Considering that the secondary IoT devices send messages to the secondary access point(SAP)by sharing the spectrum with the primary network,the interference is introduced by the IoT devices to the primary access point(PAP)which profits from the IoT devices by pricing the interference power charged by them.A practical path loss model is adopted such that the IRSs deployed between the IoT devices and SAP serve as diffuse scatterers,but each reflected signal can be aligned with its own desired ***,two transmission policies of the secondary network are investigated without/with a successive interference cancellation(SIC)*** signal-to-interference plus noise ratio(SINR)balancing is considered to overcome the nearfar effect of the IoT devices so as to allocate the resource fairly among *** propose a Stackelberg game strategy to characterize the interaction between primary and secondary *** the proposed game,the Stackelberg equilibrium is analytically derived to optimally obtain the closed-form solution of the power allocation and interference *** results are demonstrated to validate the performance of the theoretical derivations.

关键词： dedicated intelligent reflecting surfaces internet of things practical path loss cognitive network Stackelberg game

Aerial intelligent reflecting surface for secure wireless networks:Secrecy capacity and optimal trajectory strategy

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Intelligent and Converged Networks 2022年第1期3卷 119-133页

作者： Hehao Niu zheng chu zhengyu Zhu Fuhui Zhou Institute of Electronic Countermeasure National University of Defense TechnologyHefei 230037China. Institute for Communication Systems University of SurreyGuildfordGU27XHUK Shaanxi Key Laboratory of Information Communication Network and Security Xi’an University of Posts&TelecommunicationsXi’an 710121China School of Information Engineering Zhengzhou UniversityZhengzhou 450001China College of Electronic and Information Engineering Nanjing University of Aeronautics and Astronauticsand also with the Key Laboratory of Dynamic Cognitive System of Electromagnetic Spectrum SpaceNanjing University of Aeronautics and AstronauticsNanjing 210000China.

This work investigates the potential of the aerial intelligent reflecting surface(AIRS)in secure communication,where an intelligent reflecting surface(IRS)carried by an unmanned aerial vehicle(UAV)is utilized to help the communication between the ground ***,we formulate the joint design of the AIRS’s deployment and the phase shift to maximize the secrecy *** solve the non-convex objective,we develop an alternating optimization(AO)approach,where the phase shift optimization is solved by the Riemannian manifold optimization(RMO)method,while the deployment optimization is handled by the successive convex approximation(SCA)***,to reduce the computational complexity of the RMO method,an element-wise block coordinate descent(EBCD)based method is *** results verify the effect of AIRS in improving the communication security,as well as the importance of designing the deployment and phase shift properly.

关键词： aerial intelligent reflecting surface(AIRS) unmanned aerial vehicle(UAV) alternating optimization Riemannian manifold optimization(RMO) element-wise block coordinate descent(EBCD)

A NEW TECHNIQUE OF OIL TRANSPORTATION IN PIPELINE BY STEAM INJECTION

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Journal of Hydrodynamics 2002年第4期14卷 1-6页

作者： Lai, Ying-Xu zheng, Zhi-chu Shi, Zai-Hong Wu, Ying-Xiang Inst. of Mech. Chinese Acad. of Sci. Beijing 100080 China

The direct contact heating of crude oil with steam is a promising technique for improving crude oil transportation in pipelines. Crude oil temperature is increased greatly by a small quantity of steam due to the high steam latent heat and direct contact heat transfer. A jet pump was developed for injecting steam into oil in order to get a high efficiency by transferring momentum and energy from a high-velocity jet to ambient fluid. The jet pump was designed based on the free injection principle, which has no rotation parts and no converging mixing chamber, therefore it would not be blocked by the viscous crude oil. The technical feasibility of this method has been tested in the Liaohe Oilfield of China.

关键词： Crude petroleum Heat transfer Jet pumps Steam

Adult rhabdomyosarcoma originating in the temporal muscle,invading the skull and meninges:A case report

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World Journal of Clinical Cases 2021年第18期9卷 4866-4872页

作者： Geng-Huan Wang He-Ping Shen zheng-Min chu Jian Shen Department of Neurosurgery The Second Affiliated Hospital of Jiaxing UniversityJiaxing 314000Zhejiang ProvinceChina Department of Neurology The Second Affiliated Hospital of Jiaxing UniversityJiaxing 314000Zhejiang ProvinceChina

BACKGROUND Rhabdomyosarcoma(RMS)is a rare malignant tumor of mesenchymal origin that mainly affects *** cell/sclerosing RMS(SSRMS)is even *** is a new subtype that was added to the World Health Organization disease classification in *** the best of our knowledge,this is the first reported case of adult SSRMS disease classification originating in the temporal *** SUMMARY SSRMS originating in the temporal muscle of a male adult enlarged rapidly,destroyed the skull,and invaded the *** tumor was completely removed,and the postoperative pathological diagnosis was *** recovery was good and chemotherapy and radiotherapy were given after the *** up for 3 mo,no tumor *** RMS is one of the differential diagnoses for head soft tissue tumors with shortterm enlargement and skull *** computed tomography or magnetic resonance imaging is necessary for early detection of tumor invasion of the skull and brain tissue.

关键词： Rhabdomyosarcoma Temporal Muscle Skull Dura Mater Adult Case report

EXTERNAL BODY FORCEIN FINITE DIFFERENCE LATTICE BOLTZMANN METHOD

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Journal of Hydrodynamics 2005年第4期17卷 473-477页

作者： CHEN Sheng LIU Zhao-hui SHI Bao-chang zheng chu-guang State Key Laboratory of Coal Combustion Huazhong University of Science and Technology Wuhan 430074 China

A new finite difference lattice Boltzmann scheme is developed. Because of analyzing the influence of external body force roundly, the correct Navier-Stokes equations with the external body force are recovered, without any additional unphysical terms. And some numerical results are presented. The result which close agreement with analytical data shows the good performance of the model.

关键词： Finite Difference Lattice Boltzmann Method (FDLBM) body force