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Lateral Global Buckling of Submarine Pipelines Based on the Model of Nonlinear Pipe–Soil Interaction

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China Ocean Engineering 2018年第3期32卷 312-322页

作者： LIU run WANG Xiu-yan State Key Laboratory of Hydraulic Engineering Simulation and Safety Tianjin University

With the increasing development and utilization of offshore oil and gas resources, global buckling failures of pipelines subjected to high temperature and high pressure are becoming increasingly important. For unburied or semi-buried submarine pipelines, lateral global buckling represents the main form of global buckling. The pipe–soil interaction determines the deformation and stress distribution of buckling pipelines. In this paper, the nonlinear pipe–soil interaction model is introduced into the analysis of pipeline lateral global buckling, a coupling method of PSI elements and the modified RIKS algorithm is proposed to study the lateral global buckling of a pipeline, and the buckling characteristics of submarine pipeline with a single arch symmetric initial imperfection under different pipe–soil interaction models are studied. Research shows that, compared with the ideal elastic–plastic pipe–soil interaction model, when the DNV-RP-F109 model is adopted to simulate the lateral pipe–soil interactions in the lateral global buckling of a pipeline, the buckling amplitude increases, however, the critical buckling force and the initial buckling temperature difference decreases. In the DNV-RP-F109 pipe–soil interaction model, the maximum soil resistance, the residual soil resistance, and the displacement to reach the maximum soil resistance have significant effects on the analysis results of pipeline global buckling.

关键词： submarine pipeline lateral global buckling PSI element nonlinear pipe–soil interaction

Nonlinear Bifurcation and Post-buckling Analysis of Cylindrical Composite Stiffened Laminates Based on Weak Form Quadrature Element Method

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Acta Mechanica Solida Sinica 2023年第6期36卷 817-836页

作者： Xiang Ou Xiaohu Yao run Zhang School of Civil Engineering and Transportation South China University of TechnologyGuangzhouGuangdongChina

This paper presents a weak form quadrature element formulation in the analysis of nonlinear bifurcation and post-buckling of cylindrical composite stiffened laminates subjected to transverse loads.A total Lagrangian updating scheme is used in combination with arc-length method,and the branch-switching method is adopted to identify the whole post-buckling procedure of the *** formulation of the shell model and beam model are based on the basic concept of *** coincidence of discrete nodes and integration points in quadrature element endows it with compactness and conciseness in the nonlinear buckling analysis of the cylindrical stiffened *** numerical examples are firstly presented to verify the effectiveness and accuracy of present *** studies on the effects of the height-to-breadth ratio,lamination schemes,positions,distribution,number of the stiffeners on the bifurcation and post-buckling behavior are performed.

关键词： Cylindrical composite stiffened laminates Weak form quadrature element formulation Nonlinear bifurcation bucking Post-buckling analysis

Hall Algebras and Quantum Symmetric Pairs of Kac-Moody Type Ⅱ

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Acta Mathematica Sinica,English Series 2024年第3期40卷 806-822页

作者： Ming LU run Ze SHANG Department of Mathematics Sichuan UniversityChengdu 610064P.R.China

We extend the ■Hall algebra realization of ■quantum groups arising from quantum symmetric pairs,which establishes an injective homomorphism from the universal ■quantum group of Kac-Moody type to the ■Hall algebra ... 详细信息

关键词： Quantum symmetric pairs Hall algebras Quiver with involutions

Low working loss Si/4H-SiC heterojunction MOSFET with analysis of the gate-controlled tunneling effect

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Journal of Electronic Science and Technology 2023年第4期21卷 35-47页

作者： Hang Chen You-run Zhang State Key Laboratory of Electronic Thin Films and Integrated Devices School of Integrated Circuit Science and EngineeringUniversity of Electronic Science and Technology of ChinaChengdu610054China

A silicon (Si)/silicon carbide (4H-SiC) heterojunction double-trench metal-oxide-semiconductor field effect transistor (MOSFET) (HDT-MOS) with the gate-controlled tunneling effect is proposed for the first time based on simulations. In this structure, the channel regions are made of Si to take advantage of its high channel mobility and carrier density. The voltage-withstanding region is made of 4H-SiC so that HDT-MOS has a high breakdown voltage (BV) similar to pure 4H-SiC double-trench MOSFETs (DT-MOSs). The gate-controlled tunneling effect indicates that the gate voltage (V_(G)) has a remarkable influence on the tunneling current of the heterojunction. The accumulation layer formed with positive VG can reduce the width of the Si/SiC heterointerface barrier, similar to the heavily doped region in an Ohmic contact. This narrower barrier is easier for electrons to tunnel through, resulting in a lower heterointerface resistance. Thus, with similar BV (approximately 1770 V), the specific on-state resistance (R_(ON-SP)) of HDT-MOS is reduced by 0.77 mΩ·cm^(2) compared with that of DT-MOS. The gate-to-drain charge (Q_(GD)) and switching loss of HDT-MOS are 52.14% and 22.59% lower than those of DT-MOS, respectively, due to the lower gate platform voltage (V_(GP)) and the corresponding smaller variation (ΔV_(GP)). The figure of merit (Q_(GD)×R_(ON-SP)) of HDT-MOS decreases by 61.25%. Moreover, the heterointerface charges can reduce RON-SP of HDT-MOS due to trap-assisted tunneling while the heterointerface traps show the opposite effect. Therefore, the HDT-MOS structure can significantly reduce the working loss of SiC MOSFET, leading to a lower temperature rise when the devices are applied in the system.

关键词： Heterojunction On-state resistance Silicon carbide(4H-SiC)trench metal-oxide-semiconductor field effect transistors(MOSFETs) Switching loss

Characteristics of regional climate change and pattern analysis on Ordos Plateau

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Journal of Environmental Sciences 2002年第4期14卷 568-576页

作者： LI Guo qing ZHENG Yuan run Laboratory of Quantitative Vegetation Ecology Institute of BotanyChinese Academy of SciencesBeijing 100093China.

The characteristics of precipitation, temperature and their combination determine the special ecological environment pattern of Ordos Plateau. Analyzing its evolutionary trend attributes to understanding the succession process of the ecological environment of Ordos Plateau and has crucial instructional significance on the ecological restoration research being conducted in this region. Four time scales, arranging from ten days, one month, one season(growing season contrasting to non growing season)to one year were adopted to analyze the climate data which included nearly 30 years and were collected by eight weather stations on Ordos Plateau. The results indicated that the mean annual temperature and the mean monthly temperature of February, September and December, had increased significantly during the late 30 years. The annual precipitation did not show significant changes but its distribution pattern had changed obviously. The ratio of precipitation of major growing season (May October)to annual precipitation had increased distinctively,and five counties' precipitation reached statistically significant level. And the ratio of precipitation of latter growing season (September)to one year decreased significantly while the ratio of non growing season(November next April)to one year changed insignificantly. The results showed that maybe the interaction of increased mean temperature and insignificant change of precipitation in non growing season was one of the reasons why the desertification of the region was deteriorating in recent years. Using some factors closely relating to vegetation succession such as mean annual temperature, mean annual precipitation, distributive pattern of precipitation, mean temperature of the coldest month, mean temperature of the warmest month, precipitation of the warmest month, mean temperature of growing season, precipitation of growing season, potential evapotranspiration(PET)and radiative dryness index(RDI), to synthetically anal

关键词： climate change climatic synthetical regionalization restoration ecology Ordos Plateau

Design optimization for a launching system with novel structure

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Defence Technology（防务技术） 2019年第5期15卷 680-689页

作者： run-duo Cao Xiao-bing Zhang School of Energy and Power Engineering Nanjing University of Science and Technology

A launching system with novel structure using optimization method is investigated to improve the muzzle velocity of guns in this *** system has two tandem chambers of which the front one is ignited first and the other is ignited after a *** launching process of this novel system is modelled and a series of different schemes are simulated,to discover the interior ballistic performance of this novel launching *** order to obtain the optimal loading conditions,an optimization model combined with the combustion model is *** optimal schemes can improve the muzzle velocity by 20.6%without changing the parameters of *** means that this novel launch system could improve the interior ballistics performance significantly and it still has considerable potential to be ameliorated.

关键词： Interior ballistics Mobile chamber Design optimization

Bridging the Fabry–Perot cavity and asymmetric Berreman mode for long-wave infrared nonreciprocal thermal emitters

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Science China(Technological Sciences) 2024年第10期67卷 3285-3293页

作者： CHEN ZiHe YU ShiLv HU run School of Energy and Power Engineering Huazhong University of Science and TechnologyWuhan 430074China Wuhan National Laboratory for Optoelectronics Huazhong University of Science and TechnologyWuhan 430074China Department of Applied Physics Kyung Hee UniversityGyeonggi-do 17104Republic of Korea

The long-wave infrared band(8–14μm)is essential for several applications,such as infrared detection,radiative cooling,and near-field heat ***,according to Kirchhoff’s law,the intrinsic balance between thermal absorption and emission limits the further improvement of photon energy conversion and thermal ***,breaking Kirchhoff’s balance and achieving nonreciprocal thermal radiation in the long-wave infrared band are *** existing designs for nonreciprocal thermal emitters rely on grating or photonic crystal structures to achieve nonreciprocal thermal radiation at narrow peaks,which are relatively complex and typically realize bands larger than 14μ***,a sandwich structure consisting of an epsilon-nearzero(ENZ)magneto-optical layer(MOL),a dielectric layer(DL),and a metal layer is proposed to achieve a strong nonreciprocal effect in the long-wave infrared band,which is mainly attributed to the strengthening of the asymmetric Berreman mode by the Fabry–Perot *** addition,the impact of the incident angle,DL thickness,and DL refractive index on the nonreciprocal thermal radiation has been ***,by replacing the ENZ MOL with the gradient ENZ MOL,the existence of the DL can further improve the nonreciprocity of the broadband nonreciprocal thermal *** proposed work promotes the development and application of nonreciprocal energy devices.

关键词： long-wave infrared band nonreciprocal thermal radiation sandwich structure Fabry–Perot cavity asymmetric berreman mode

Nondegloving technique for Peyronie＇s disease with penile prosthesis implantation and double dorsal-ventral patch graft

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Asian Journal of Andrology 2018年第1期20卷 90-92页

作者： Andrew Fang run Wang Division of Urology University of Texas McGovern Medical School Houston Texas 77030 USA Department of Urology University of Texas MD Anderson Cancer Center Houston Texas 77030 USA

Acircumcising incision to deglove the penis for penile prosthesis （PP） implantation can increase the risk of ischemic injury to the glans penis. In order to avoid vascular complications, we describe a novel technique utilizing a ventral incision to perform the PP implantation and a double-dorsal patch graft, or ＂sliding technique＂（ST）, in patients with severe Peyronie＇s disease （PD）.＇Ihree patients with severe PD and erectile dysfunction at our institution underwent ST and PP implantation through a ventral incision. ＂[his new approach was not only successful in facilitating the ST and PP implantation in these patients but also allowed for adequate exposure of the penile shaft with no reported loss of sensation.

关键词： vascular complications erectile dysfunction

NUMERICAL SIMULATION OF THREE-DIMENSIONAL TURBULENT FLOW NEAR BODY SURFACE WITH LONGITUDINAL VORTICES

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Journal of Hydrodynamics 1991年第1期3卷 26-36页

作者： Gao, Gao Zhao, run-yuan Wuhan Inst of Water Transportation Engineering Wuhan China

A calculating model of generalized partially-parabolic approximation is adopted in the research of numerical simulation of 3-D turbulent flow near body surface with longitudinal vortices in this paper. An analytical solution for Poisson equation is presented to generate the 3-D body-fitted coordinate system. The finite analytic method, which introduces 'virtual' time variable, is used calculating examples. The partially-parabolic approximation is made in the transformed equations. Compared with that made in the physical domain, it allows the equations to retain more terms. In 'zero' equation turbulence model, longitudinal eddy-viscosity and transverse eddy-viscosity are determined by using empiric formulae appropriate to inner layer and outer layer respectively. Of three example calculations, the results of turbulent flow past a flat plate with longitudinal vortices are compared with that of available experimental data. The comparison is found to be satisfactory. The results of the others - turbulent flow along a long cylinder and that past an ellipsoid with longitudinal vortices, are qualitatively reasonable.

关键词： Computer Simulation Computers Applications Hydrodynamics Mathematical Models Mathematical Techniques Differential Equations