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An Improved Approach for Interaction of Wave with Floating Spheres and Its Applications

China Ocean Engineering 2023年第1期37卷 115-130页

作者： LIU Can dong zhi-yong PAN Yun TONG Huan-huan YANG li-jing College of Civil Engineering Zhejiang University of TechnologyHangzhou 310023China School of Naval Architecture and Maritime Zhejiang Ocean UniversityZhoushan 316022China School of Marine Engineering Equipments Zhejiang Ocean UniversityZhoushan 316022China

To develop and utilize marine resources in the deep sea, the higher requirements for floating structures, which are operated in marine environment for a long term, have been put forward. Reasonable structure type and accurate force analysis are favorable guarantees to improve the survival performance and working performance of the floating structures. Floating spheres fastened by mooring cable were widely used in floating structures. In this paper, the wave forces of the floating sphere are efficiently and accurately calculated by solving the geometric relationship between the non-submerged floating sphere and wave surface. Combined with the hydrodynamic calculation of mooring cables based on the lumped mass method, the coupled motion model of multi-floating spheres fastened by multi-mooring cable was established under wave action. Furthermore, according to the floating structures fastened by mooring cable in the actual ocean engineering, the topological method of multi-mooring cables fastening the multifloating spheres was expounded from simple to complex. Finally, the modeling method and preliminarily hydrodynamic characteristics of the fastened floating structures, including the mooring system of renewable energy devices, ocean buoy, and coral nursery, were presented and analyzed in detail. The obtained results showed that the method for calculating the wave force on the floating sphere developed in this paper can accurately describe the motion process of the floating mooring sphere and the force on the mooring cable. Also, the topological method of multiple buoys and multiple mooring cables could efficiently establish various numerical hydrodynamic models of fastened buoys in ocean engineering.

关键词： floating sphere mooring cable wave forces hydrodynamic model ocean engineering

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CAVITATION CONTROL BY AERATION AND ITS COMPRESSIBLE CHARACTERISTICS

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Journal of Hydrodynamics 2006年第4期18卷 499-504页

作者： dong zhi-yong SU Pei-lan School of Civil Engineering and Architecture Zhejiang University of Technology Hangzhou 310032 China School of Forestry Shanxi Agricultural University Taigu 030801 China

This paper presents an experimental investigation and a theoretical analysis of cavitation control by aeration and its compressible characteristics at the flow velocity V=20m/s-50m/s. Pressure waveforms with and without aeration in cavitation region were measured. The variation of compression ratio with air concentration was described, and the relation between the least air concentration to prevent cavitation erosion and flow velocity proposed based on our experimental study. The experimental results show that aeration remarkably increases the pressure in cavitation region, and the corresponding pressure wave exhibits a compression wave/shock wave. The pressure increase in cavitation region of high-velocity flow with aeration is due to the fact that the compression waves/shock wave after the flow is aerated. The compression ratio increases with air concentration rising. The relation between flow velocity and least air concentration to prevent cavitation erosion follows a semi-cubical parabola. Also, the speed of sound and Mach number of high-velocity aerated flow were analyzed.

关键词： cavitation control by aeration compression wave/shock wave least air concentration speed of sound compression ratio

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NUMERICAL SIMULATION OF SKIMMING FLOW OVER MILD STEPPED CHANNEL

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Journal of Hydrodynamics 2006年第3期18卷 367-371页

作者： dong zhi-yong LEE Joseph Hun-wei School of Civil and Architecture Engineering Zhejiang University of Technology Hangzhou 310014 China Department of Civil Engineering The University of Hong Kong Hong Kong China

Numerical simulation of stepped channel flow was conducted using turbulence models based on the VOF technique. Stepped channel flow is a complicated air-water two-phase flow with free surface, which can be divided into three flow regimes： skimming flow, nappe flow and transition flow. The characteristics of skimming flow over mild stepped channel was investigated, including friction factors, air concentration profiles velocity field, clear-water and bulked depths, static pressure, etc. Smooth channel flow was also simulated to compare the hydraulic characteristics of the stepped channel flow with the smooth one. Comparisons between the computed and the measured were made. Furthermore, comparison of the computed air concentration with Straub and Anderson＇s data was also performed. The Fluent 6.1 software was employed to conduct this numerical simulation work.

关键词： numerical simulation skimming flow stepped channel Volume Of Fluid （VOF） technique

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AN EXPERIMENTAL INVESTIGATION OF PRESSURE AND CAVITATION CHARACTERISTICS OF HIGH VELOCITY FLOW OVER A CYLINDRICAL PROTRUSION IN THE PRESENCE AND ABSENCE OF AERATION

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Journal of Hydrodynamics 2008年第1期20卷 60-66页

作者： dong zhi-yong LIU zhi-ping WU Yi-hong ZHANG dong China Hydraulic and Municipal Engineering Research Institute Zhejiang University of Technology Hangzhou 310014 China Institute of Water Resources and Hydroelectric Power Research Beijing 100038 China

This article experimentally investigated the pressure and cavitation characteristics of high velocity flow over a surface irregularity with and without aeration in a non-circulating water tunnel system. The surface irregularity is a cylindrical protrusion made of stainless steel of 6 mm diameter and 2 mm height. Pressures with and without aeration were measured with MPX400D pressure transducers and real-timely acquired by a SINOCERA YE6263 data acquisition system. Variations in flow regimes with and without aeration were observed. Pressure profiles and their variations with air concentration upper and lower cylindrical protrusion on the invert and obvert walls were determined. Variations of cavitation number with air concentration lower cylindrical protrusion were analyzed. Also, cavitation numbers in the presence and absence of aeration were compared.

关键词： cylindrical protrusion aeration pressure cavitation number high velocity flow

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SiGe BiCMOS低噪声放大器激光单粒子效应研究

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物理学报 2024年第4期73卷 200-208页

作者：李培董志勇郭红霞张凤祁郭亚鑫彭治钢贺朝会西安交通大学核科学与技术学院西安710049 西北核技术研究院强脉冲辐射环境模拟与效应国家重点实验室西安710024

随着CMOS工艺的日益成熟和SiGe外延技术水平的不断提高,SiGe BiCMOS低噪声放大器(LNA)广泛应用于空间射频收发系统的第一级模块.SiGe HBT作为SiGe BiCMOS LNA的核心器件,天然具有优异的低温特性、抗总剂量效应和抗位移损伤效应的能力,然... 详细信息

随着CMOS工艺的日益成熟和SiGe外延技术水平的不断提高,SiGe BiCMOS低噪声放大器(LNA)广泛应用于空间射频收发系统的第一级模块.SiGe HBT作为SiGe BiCMOS LNA的核心器件,天然具有优异的低温特性、抗总剂量效应和抗位移损伤效应的能力,然而,其瞬态电荷收集引起的空间单粒子效应是制约其空间应用的瓶颈问题.本文基于SiGe BiCMOS工艺低噪声放大器开展了单粒子效应激光微束实验,并定位了激光单粒子效应敏感区域.实验结果表明,SiGe HBT瞬态电荷收集是引起SiGe BiCMOS LNA单粒子效应的主要原因.TCAD模拟表明,离子在CMOS区域入射时,电离径迹会越过深沟槽隔离结构,进入SiGe HBT区域产生电子空穴对并引起瞬态电荷收集.ADS电路模拟分析表明,单粒子脉冲瞬态电压在越过第1级与第2级之间的电容时,瞬态电压峰值骤降,这表明电容在传递单粒子效应产生的瞬态脉冲过程中起着重要作用.本文实验和模拟工作为SiGe BiCMOS LNA单粒子效应抗辐射设计加固提供了技术支持.

关键词： SiGe BiCMOS工艺低噪声放大器单粒子效应激光模拟实验 TCAD数值模拟 ADS电路模拟

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替奈普酶静脉溶栓序贯替罗非班静脉泵入治疗急性脑梗死的效果分析

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中国现代药物应用 2024年第13期18卷 6-9页

作者：董智勇河北省香河县人民医院神经内科 065400

目的探究替奈普酶静脉溶栓序贯替罗非班静脉泵入治疗急性脑梗死的效果。方法68例急性脑梗死患者作为研究对象,将其按照随机分配法分为研究组和对照组,每组34例。两组患者入院后均予以替奈普酶静脉溶栓治疗,对照组患者在静脉溶栓后24 h... 详细信息

目的探究替奈普酶静脉溶栓序贯替罗非班静脉泵入治疗急性脑梗死的效果。方法68例急性脑梗死患者作为研究对象,将其按照随机分配法分为研究组和对照组,每组34例。两组患者入院后均予以替奈普酶静脉溶栓治疗,对照组患者在静脉溶栓后24 h采用阿司匹林治疗,研究组在静脉溶栓后随即静脉泵入替罗非班。对比两组患者的神经元特异性烯醇化酶水平、S100β蛋白水平、神经功能缺损程度评分和不良事件发生率。结果研究组患者的神经元特异性烯醇化酶水平、S100β蛋白水平、神经功能缺损程度评分分别为(16.24±2.41)ng/ml、(1.25±0.27)μg/L、(3.25±1.26)分,明显低于对照组的(18.75±1.43)ng/ml、(1.68±0.39)μg/L、(6.26±1.85)分,差异具有统计学意义(P<0.05)。研究组患者的不良事件发生率5.88%明显低于对照组的23.53%,差异具有统计学意义(P<0.05)。结论对于急性脑梗死患者来说,采用替奈普酶静脉溶栓序贯替罗非班静脉泵入治疗能够有效降低患者神经元特异性烯醇化酶、S100β蛋白水平及神经功能缺损程度、不良事件发生率,值得广泛应用。

关键词：急性脑梗死替奈普酶静脉溶栓替罗非班

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Preliminary clinical outcomes of percutaneous kyphoplasty with Sky-bone expander

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Chinese Medical Journal 2007年第9期120卷 761-766页

作者： ZHENG Zhao-min KUANG Guan-ming dong zhi-yong K.M.C. Cheung William W. Lu LI Fo-bao Department of Spine Surgery First Affiliated Hospital of Sun Yat-sen University Guangzhou 510080 China Department of Orthopaedics and Traumatology University of Hong Kong Hong Kong China

Background Percutaneous kyphoplasty （PKP） using balloon expander has been proved to be effective in the treatment of painful vertebral compression fractures. Recently, Sky-bone expander, an alternative bone expander for PKP has been developed. The purpose of this study was to show our preliminary clinical outcomes of PKP with Sky-bone expander. Methods PKP with Sky-bone expander was performed in 25 patients （30 vertebrae）. The operation time, bleeding volume, cement volume injected were recorded. The pain and functional activities of the patients before and after the operation were compared using Wilcoxon signed-rank test. The cement distribution in the vertebrae, vertebral height restoration, and kyphosis correction after the procedure were evaluated by radiography. The pre- and post-operative absolute values of the vertebral height and kyphotic angle were compared by paired-sample t test. All the patients were followed up by telephone or clinic consulting after being discharged from our hospital. Results The procedure was performed successfully in all the patients. Bipedicular injection was used in 2 of the patients, and unipedicular injection was made in the others. The operation time ranged from 25 to 120 minutes （45 minutes per vertebra on average）. The average bleeding volume was about 20 ml. Polymethylmethacrylate 1.5-5.0 ml （mean, （3.15±0.78） ml） was injected through each pedicle into all the patients except one, who received calcium sulphate 3.5 ml instead. The patients were followed up for 12-15 months （13.5 months on average）. The mean visual analogue scale （VAS） score, Oswestry Disability Index, anterior, midline, and posterior vertebral height, and kyphotic angle of the patients were improved significantly at the end of the follow-up compared with those before the operation. （2.5± 1.3, 35.1%, （20.94±6.15） mm, （20.26±4.59） mm, （26.72±3.49） mm, and 8.2 degrees vs. 8.5±1.9, 61.2%, （19.11±6.72） mm, （15.88±5.73） mm, （25.78±3.67） mm, and 17.3 degrees; all P〈0.05）. The cement distribution with unipedicu

关键词： kyphoplasty fracture, compression osteoporosis

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Enhanced memristor performance via coupling effect of oxygen vacancy and ferroelectric polarization

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Journal of Materials Science & Technology 2024年第4期171卷 139-146页

作者： zhi Yun Yue zhi dong Zhang Zhan Jie Wang Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China School of Materials Science and Engineering University of Science and Technology of ChinaShenyang 110016China School of Materials Science and Engineering Shenyang University of TechnologyShenyang 110870China

As a new type of nonvolatile memory,the resistive memristor has broad application prospects in in-formation storage and neural computing based on its excellent resistive switching(RS)performance.At present,it is still a great challenge to improve both ferroelectric polarization and leakage current to achieve a high RS on/offratio of ferroelectric memristors.Herein,epitaxial Pb(Zr_(0.40)Ti_(0.60))O_(3)(PZT)thin films with low content Ca doping were deposited on the Nb:SrTiO_(3)substrate to prepare PCZT/NSTO het-erostructures and their RS behaviors were studied.The research findings show that compared with pure PZT film,the ferroelectric polarization of 1-mol%-Ca-doped PZT film is slightly improved,while the leak-age current is increased by three orders of magnitude.Therefore,the RS on/offratio reaches 2.5×10^(5),about three orders of magnitude higher than pure PZT films.The theoretical analysis reveals that the RS behavior of PCZT/NSTO heterostructures is controlled by the PCZT/NSTO interfacial barrier and the space charge-limited current mechanism.Our results demonstrate that the ferroelectricity and electricity of ferroelectric thin films can be improved simultaneously by doping low-content Ca ions to increase the RS performance,which provides a good reference for the development of high-performance ferroelectric memristor devices.

关键词： Ferroelectric memristor Ca-doped PZT Ferroelectric polarization Oxygen vacancies Resistive switching

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A New Method for Solving Nonlinear Partial Differential Equations Based on Liquid Time-Constant Networks

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Journal of Systems Science & Complexity 2024年第2期37卷 480-493页

作者： SUN Jiuyun dong Huanhe FANG yong College of Mathematics and Systems Science Shandong University of Science and TechnologyQingdao 266590China

In this paper,physics-informed liquid networks(PILNs)are proposed based on liquid time-constant networks(LTC)for solving nonlinear partial differential equations(PDEs).In this approach,the network state is controlled via ordinary differential equations(ODEs).The significant advantage is that neurons controlled by ODEs are more expressive compared to simple activation functions.In addition,the PILNs use difference schemes instead of automatic differentiation to construct the residuals of PDEs,which avoid information loss in the neighborhood of sampling points.As this method draws on both the traveling wave method and physics-informed neural networks(PINNs),it has a better physical interpretation.Finally,the KdV equation and the nonlinear Schr¨odinger equation are solved to test the generalization ability of the PILNs.To the best of the authors’knowledge,this is the first deep learning method that uses ODEs to simulate the numerical solutions of PDEs.

关键词： Nonlinear partial differential equations numerical solutions physics-informed liquid networks physics-informed neural networks

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CAVITATION CHARACTERISTICS OF HIGH VELOCITY FLOW WITH AND WITHOUT AERATION ON THE ORDER OF 50m/s

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Journal of Hydrodynamics 2007年第4期19卷 429-433页

作者： dong zhi-yong CHEN Lei JU Wen-jie School of Civil Engineering and Architecture Zhejiang University of Technology Hangzhou 310032 China

Experimental study of cavitation characteristics with and without aeration was conducted at the flow velocity 50m/s in the non-circulating type water tunnel in the Hydraulics Laboratory at Zhejiang University of Technology. Variations of pressure and cavitation number with air concentration, pressure waveforms as well as cavitation erosion level of concrete specimen with and without aeration were obtained. The effects of cavitation control by aeration were analyzed.

关键词： cavitation erosion aeration pressure change cavitation number the order of 50 m/s

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