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New formula for predicting the plastic buckling pressure of steel torispherical heads under internal pressure

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2024年第8期25卷 618-630页

作者： Sheng YE Keming LI jinyang zheng Shan SUN Institute of Process Equipment Zhejiang UniversityHangzhou 310027China Engineering Research Center for High Pressure Process Equipment and Safety of Ministry of Education Hangzhou 310027China State Key Laboratory of Fluid Power and Mechatronic Systems Hangzhou 310058China

Thin-walled torispherical heads under internal pressure can fail by plastic buckling because of compressive circumferential stresses in the head ***,existing formulas still have limitations,such as complicated expressions and low accuracy,in determining buckling *** this paper,we propose a new formula for calculating the buckling pressure of torispherical heads based on elastic-plastic analysis and experimental ***,a finite element(FE)method based on the arc-length method is established to calculate the plastic buckling pressure of torispherical heads,considering the effects of material strain hardening and geometrical *** buckling pressure results calculated by the FE method in this paper have good consistency with those of BOSOR5,which is a program for calculating the elastic-plastic bifurcation buckling pressure based on the finite difference energy ***,the effects of geometric parameters,material parameters,and restraint form of head edge on buckling pressure are ***,a new formula for calculating plastic buckling pressure is developed by fitting the curve of FE results and introducing a reduction factor determined from experimental ***,based on the experimental results,we compare the predictions of the new formula with those of existing *** is shown that the new formula has a higher accuracy than the existing ones.

关键词： Torispherical head Plastic buckling Elastic-plastic analysis Prediction formula Finite element method

Liquid bridge force between two unequal-sized spheres or a sphere and a plane

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Particuology 2011年第4期9卷 374-380页

作者： Youchuan Chen Yongzhi Zhao Hongli Gao jinyang zheng Institute of Chemical Process Equipment Department of Chemical and Biochemical Engineering Zhejiang University Hangzhou 310027 China Maoming University Maoming Guangdong 525000 China

Liquid bridge force acting between wet particles is an important property in particle characterization. This paper deals with liquid bridge force between either two unequal-sized spherical particles or a sphere and a flat plate under conditions where gravitational effect arising from bridge distortion is negligible. In order to calculate the force of the liquid bridge efficiently and accurately, expressions of liquid configuration and liquid bridge force were derived by building a mechanical model, which assumes the liquid bridge to be circular in shape between either two unequal-sized spheres or a sphere and a plane. To assess the accuracy of the numerical results of the calculated liquid bridge forces, they were compared to the nuhlished experimental data.

关键词： Liquid bridge force Filling angle Nonzero contact angle Discrete element method

An erosion model for the discrete element method

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Particuology 2017年第5期15卷 81-88页

作者： Yongzhi Zhao Huacling Ma Lei Xu jinyang zheng Institute of Process Equipment College of Energy Engineering Zhejiang University Hangzhou 310027 China

A shear impact energy model （SIEM） of erosion suitable for both dilute and dense particle flows is pro- posed based on the shear impact energy of particles in discrete element method （DEM） simulations. A number of DEM simulations are performed to determine the relationship between the shear impact energy predicted by the DEM model and the theoretical erosion energy. Simulation results show that nearly one-quarter of the shear impact energy will be converted to erosion during an impingement. According to the ratio of the shear impact energy to the erosion energy, it is feasible to predict erosion from the shear impact energy, which can be accumulated at each time step for each impingement during the DEM simulation. The total erosion of the target surface can be obtained by summing the volume of material removed from each impingement. The proposed erosion model is validated against experiment and results show that the SIEM combined with DEM accurately predicts abrasive erosions.

关键词： Discrete element method Erosion Wear Impact angle Shear impact energy mode

Transition of axial segregation patterns in a long rotating drum

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Particuology 2014年第2期12卷 128-133页

作者： Zequn Cui Yongzhi Zhao Youchuan Chen Xiao Liu zhengli Hua Chilou Zhou jinyang zheng State Key Laboratory of Chemical Engineering Institute of Process EquipmentDepartment of Chemical and Biochemical EngineeringZhejiang University Institute of Coal Chemistry Chinese Academy of Sciences

Axial segreganon or a bidisperse mixture of particles in a long rotating drum is studied using the discrete element method. Simulation results show that particle interaction is responsible for axial segregation, the patterns of which are influenced by the end wall effect. Axial segregation patterns transform under competing influences of the end walls and the particle interaction forces. The two influential factors vary with various rotational speeds and end wall friction levels. The result is the transition of different axial segregation patterns： two large-particle bands at both ends, two small-particle bands at both ends, or a random segregation pattern where either a large-particle band or small-particle band may appear at either end.

关键词： Long rotating drumDiscrete element methodAxial segregation patternEnd wall effectRotational speed

Rarefaction and Temperature Gradient Effect on the Performance of the Knudsen Pump

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Chinese Journal of Mechanical Engineering 2012年第4期25卷 745-752页

作者： YE Jianjun YANG Jian zheng jinyang DING Xianting WONG Ieong LI Weizhong CHEN Cong Institute of Process Equipment Zhejiang University Hangzhou 310027 China Engineering Research Center of High Pressure Process Equipment and SaJety oJ Mini'~try oJ l~ctucatton Zhejiang University Hangzhou 310027 China Department of Mechanical andAerospace Engineering University of California Los Angeles 90095 U.S.A School of Energy and Power Engineering Dalian University of Technology Dalian 116024 China

The prediction of the multiscale flow in the Knudsen pump is important for understanding its pumping ***,there is little research on such interesting multiscale phenomenon in the Knudsen *** this paper,a novel numerical analysis method combining the direct simulation Monte Carlo（DSMC） method with the smoothed particle hydrodynamics（SPH） method is presented for simulating the multiscale flow,which is often encountered in the application of the Knudsen *** and accuracy of the new method are given by comparing its results with that of the previous *** the coupled multiscale approach,the rarefaction and the temperature drive are studied,which are two main factors on the performance of the Knudsen *** investigate the effect of rarefaction on the performance of the Knudsen pump,various pump operation pressures are *** flow characteristics and pumping ability at different rarefaction are analyzed,and the phenomenon of the multiscale flow is also *** cases with different linear or nonlinear temperature gradients are set to investigate the effect of temperature gradient on the performance of the Knudsen *** flow characteristics of the Knudsen pump such as the velocity,pressure increase,and the mass flowrate are presented.A unique phenomenon,the reverse transpiration effect caused by the nonlinear temperature gradient is studied,and the reason of the significant pressure increase in the pump channel is also *** the multiscale gas flow is widely encountered in the microflow systems,the above method and its results can also be greatly beneficial and provide significant insights for the design of the MEMS devices.

关键词： thermal transpiration Knudsen pump mass flowrate rarefaction temperature gradient-driven

Circulating tumor cells: Biological features and survival mechanisms

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BIOCELL 2023年第8期47卷 1771-1781页

作者： XIAOFENG LI jinyang zheng JINFENG ZHU XIN HUANG HUANHUAN ZHU BINGDI CHEN Department of Oncology Affiliated Quanzhou First Hospital of Fujian Medical UniversityQuanzhouChina Department of Pathology Affiliated Quanzhou First Hospital of Fujian Medical UniversityQuanzhouChina Department of Medical Oncology Affiliated Quanzhou First Hospital of Fujian Medical UniversityQuanzhouChina Department of Dermatology School of MedicineTongji HospitalTongji UniversityShanghaiChina Department of Central Laboratory Shanghai Tenth People’s HospitalShanghaiChina Shanghai East Hospital The Institute for Biomedical Engineering&Nano ScienceTongji University School of MedicineShanghaiChina

Circulating tumor cells(CTCs)are neoplastic cells that are detached from primary tumors and enter *** and characterization of CTCs are of significance in cancer diagnosis,prognosis,and treatment *** survival in the bloodstream is a limiting step for the development of metastases in distant *** technological advances,especially in single-cell molecular analyses have uncovered heterogeneous CTC survival *** epithelial-to-mesenchymal transition(EMT),increasing stem cell-like properties,and forming cell clusters enable CTCs to adapt to the harsh microenvironment of the *** and releasing several immunosuppressive molecules help CTCs escape from anti-cancer immune *** review article summarizes the biological characteristics of CTCs and focuses on the recent understanding of the mechanisms by which CTCs survive in ***,the clinical and therapeutic implications of CTCs are discussed.

关键词： Anoikis Circulating tumor cells Heterogeneity Immune evasion Plasticity

A review of nondestructive examination technology for polyethylene pipe in nuclear power plant

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Frontiers of Mechanical Engineering 2018年第4期13卷 535-545页

作者： jinyang zheng Yue ZHANG Dongsheng HOU Yinkang QIN Weican GUO Chuck ZHANG Jianfeng SHI Institute of Process Equipment Zhejiang University Hangzhou 310027 China Zhejiang Provincial Special Equipment Inspection and Research Institute Hangzhou 310027 China Georgia Tech Manufacturing Institute Georgia Institute of TechnologyAtlanta GA 30332 USA

Polyethylene （PE） pipe, particularly high- density polyethylene （HDPE） pipe, has been successfully utilized to transport cooling water for both non-safety- and safety-related applications in nuclear power plant （NPP）. Though ASME Code Case N755, which is the first code case related to NPP HDPE pipe, requires a thorough nondestructive examination （NDE） of HDPE joints. However, no executable regulations presently exist because of the lack of a feasible NDE technique for HDPE pipe in NPP. This work presents a review of current developments in NDE technology for both HDPE pipe in NPP with a diameter of less than 400 mm and that of a larger size. For the former category, phased array ultrasonic technique is proven effective for inspecting typical defects in HDPE pipe, and is thus used in Chinese national standards GB/T 29460 and GB/T 29461. A defect- recognition technique is developed based on pattern recognition, and a safety assessment principle is summa- rized from the database of destructive testing. On the other hand, recent research and practical studies reveal that in current ultrasonic-inspection technology, the absence of effective ultrasonic inspection for large size was lack of consideration of the viscoelasticity effect of PE on acoustic wave propagation in current ultrasonic inspection technology. Furthermore, main technical problems were analyzed in the paper to achieve an effective ultrasonic test method in accordance to the safety and efficiency requirements of related regulations and standards. Finally, the development trend and challenges of NDE test technology for HDPE in NPP are discussed.

关键词： polyethylene pipe nuclear power plant ultrasonic inspection nondestructive testing safety assessment

Enhancing mixing of particles by baffies in a rotating drum mixer

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Particuology 2011年第3期9卷 270-278页

作者： Maoqiang Jiang Yongzhi Zhao Gesi Liu jinyang zheng State Key Laboratory of Chemical Engineering Institute of Chemical Process Equipment Department of Chemical and Biochemical Engineering Zhejiang University Hangzhou 310027China

Baffles with shape of ＂-＂（single baffle）, ＂＋＂（cross-baffles with four arms） and （baffles with 6 arms） are used to enhance the mixing of particles in a rotating drum mixer. A micro-dynamics study of mixing and segregation ofa bi-disperse system of two particle sizes in the rotating drum with these three kinds of baffles is carried out using the discrete element method （DEM）. The effect of the baffles on mixing, and the mechanisms of mixing enhancement by the baffles are discussed and analyzed. Simulation results show that in an unbaffled drum mixer, particle convection, particle diffusion, and size segregation of hi- disperse particles, all play important roles in the mixing process; whereas size segregation will be largely restrained when the drum mixer has a baffle, regardless of its shape, and the degree of mixing is higher than that in an unbaffled drum mixer. The different mixing characteristics for ＂-＂ shaped baffle, ＂＋＂ baffle, and baffle are revealed by the simulation results. For ＂＋＂ or style baffles, there is an optimal size of baffles for the mixing of particles, and the ootimal mixing efficiency is higher than that for ＂-＂ baffle.

关键词： Particle mixing Size segregation Baffle Drum mixer Discrete element method (DEM)

Pd@Ir-LOD multienzyme utilizing endogenous lactate consumption cooperates with photothermal for tumor therapy

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Nano Research 2024年第1期17卷 270-281页

作者： Zichen Ye Yun Li Jingchao Li Xinyan Hu jinyang zheng Gongxin Zhang Sijin Xiang Tianbao Zhu Zhide Guo Xiaolan Chen State Key Laboratory for Physical Chemistry of Solid Surfaces Collaborative Innovation Center of Chemistry for Energy Materials and Engineering Research Center for Nano-Preparation Technology of Fujian ProvinceCollege of Chemistry and Chemical EngineeringXiamen UniversityXiamen 361005China State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics&Center for Molecular Imaging and Translational Medicine School of Public Health Xiamen UniversityXiamen 361102China The High Educational Key Laboratory for Biomedical Engineering&Key Laboratory of Fire Retardant Materials of Fujian Province Department of BiomaterialsCollege of MaterialsXiamen UniversityXiamen 361102China

Lactic acid(LA)plays a major role in the occurrence,development,and spread of *** by its high accumulation in tumor site,a novel lactate oxidase(LOD)conjugated two-dimensional Pd@Ir nanoplatform(Pd@Ir-LOD,PIL)was fabricated to combine cascade reaction with photothermal for tumor *** detail,the overexpressed LA in tumor microenvironment(TME)was a key factor to activate the PIL-based cascade reaction:(1)Plenty of H_(2)O_(2)could be generated from LA by the catalysis of LOD with O_(2);(2)potent·OH was produced from H_(2)O_(2)due to the peroxidase(POD)-like activity of PIL;(3)meantime,PIL’s catalase(CAT)-like activity could decompose part H_(2)O_(2)into O_(2)to achieve the purpose of LA cyclic ***,the reduced glutathione(GSH)scavenging capability of PIL might protect the produced reactive oxygen species(ROS)from being cleared to further improve the cascade therapeutic *** importantly,PIL had excellent photothermal conversion efficiency(37.35%)and manifested a surprising temperature rising effect in *** together,the decreasing LA concentration,accumulation of high-toxic ROS,the depletion of GSH together with the higher intra-tumoral temperature potently enhanced in vivo antitumor ***,a promising therapeutic tactic based on PIL integrating endogenous LA consumption,chemodynamic therapy(CDT),and photothermal therapy(PTT)has been put forward.

关键词： lactate oxidase chemodynamic therapy photothermal therapy cascade reaction tumor microenvironment