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Establishment of a pig model with enteric and portal venous drainage of pancreatoduodenal transplantation

World Journal of Gastroenterology 2005年第35期11卷 5475-5479页

作者： Zhao-da zhang Fang-hai Han Ling-Xiang Meng Third GeneralDepartment West China Hospital of Sichuan University Chengdu610041 Sichuan Province China

AIM： To establish the pig model of pancreatoduodena transplantation with enteric drainage （ED） and porta venous drainage （PVD）. METHODS： Forty-six hybrid Landrace pigs were divided into two groups （donors and recipients） randomly, and pancreatoduodenal allotransplantation was performed. Donors were perfused via abdominal aorta without clamping the portal venous outflow with UW solution at 80-100 cm H2O after heparinization. Whole pancreatoduodenal grafts were harvested with segments of abdominal aorta and portal vein, and shaped under 4℃ UW solution. Then, end-to-end anastomosis was performed with the donor iliac artery bifurcation Y graft to the recipient superior mesenteric artery and celiac artery. Furthermore, type I diabetes model was made by removal of the recipient pancreas. The venous anastomosis was reconstructed between the donor portal vein and the recipient superior mesentery vein. Meanwhile, end-toside anastomosis was performed with the donor common iliac artery bifurcation Y graft to the recipient abdominal aorta, and side-to-side intestinal anastomosis was performed between the donor duodenum and the recipient jejunum. External jugular vein was intubated for transfusion. Levels of plasma glucose, insulin and glucagon were measured during the operation and on the 1^st 3^rd 5^th and 7^th d after operation. RESULTS： Pancreatoduodenal allotransplantation was performed on 23 pigs of which 1 died of complication of anesthesia. The success rate of operation was 95.6%. Complications of operation occurred in two cases in which one was phlebothrombosis with an incidence of 4.6%, and the other was duodenojejunal anastomotic leak with an incidence of 4.6%. The level of plasma glucose decreased within 30 min, after removal of pancreas and recovered on the 2^nd after operation. The level of plasmainsulin and glucagon increased within 30 min after removal of pancreas and recovered on the 2^nd d after operation. Rejection occurred on the 1^st and reached the worst le

关键词： Pancreatoduodenal transplantation Entericdrainage Portal venous drainage

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A Novel Approach for the Effective Thermal Conductivity of Porous Ceramics

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Chinese Journal of Aeronautics 2006年第B12期19卷 244-247页

作者： ZHU Qiang zhang Fan-wei zhang Yue zhang da-hai LI Zhong-ping School of Materials Science and Engineering Beijing University of .4eronautics and Astronautics Beijing 100083 China National Key Laboratory of Advanced Functional Composite Materials Aerospace Research Institute of Materials and Processing Technology Beijing 100076China

A new approach in combination of the effective medium theory with the equivalent unit in numerical simulation was developed to study the effective thermal conductivity of porous ceramics. The finite element method was used to simulate the heat transfer process which enables to acquire accurate results through highly complicated modeling and intensive computation. An alternative approach to mesh the material into small cells was also presented. The effective medium theory accounts for the effective thermal conductivity of cells while the equivalent unit is subsequently applied in numerical simulation to analyze the effective thermal conductivity of the porous ceramics. A new expression for the effective thermal conductivity, allowing for some structure factors such as volume fraction of pores and thermal conductivity, was put forward, and the results of its application was proved to be close to those of the mathematical simulation.

关键词： effective thermal conductivity porous ceramics equivalent unit numerical simulation

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Optimization Study on the Blade Profiles of A Horizontal Axis Tidal Turbine Based on BEM-CFD Model

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China Ocean Engineering 2019年第4期33卷 436-445页

作者： zhang da-hai DING Lan HUANG Bin CHEN Xue-meng LIU Jin-tao Ocean College Zhejiang University Zhoushan 316021 China Beijing Institute of Control Engineering Beijing 100190 China

In order to increase the performance of horizontal tidal turbines, a multi-objective optimization model was proposed in this study. Firstly, the prediction model for horizontal tidal turbines was built, which coupled the blade element momentum (BEM) theory and the CFD calculation. Secondly, a multi-objective optimization method coupled the response surface method (RSM) with the multi-objective genetic algorithm NSGA-II was applied to obtain the optimal blade profiles. The pitch angle and the chord length distribution were chosen as the design variables, while the mean power coefficient and the variance of power coefficient were chosen as the objective functions. With the mean power coefficient improved by 4.1% and the variance of power coefficient decreased by 46.7%, results showed that both objective functions could be improved.

关键词： tidal turbine BEM-CFD multi-objective optimization power coefficient

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Explicit Expression of Seniority Particle Operator and Its Properties in Quasi-spin Theory

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Communications in Theoretical Physics 2006年第5X期46卷 909-913页

作者： zhang Bo LU da-hai DENG Wei-Zhen CHEN Xiao-Lin Institute of Theoretical Physics Peking University Beijing 100871 China

The explicit expression of the seniority particle operator and its properties in the quasi-spin theory of nuclear physics is presented in this paper. The seniority particle operator can be used to construct D-pair in ... 详细信息

关键词： quasi-spin seniority particle seniority mixing problem

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Design,Optimization and Numerical Modelling of A Novel Floating Pendulum Wave Energy Converter with Tide Adaptation

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China Ocean Engineering 2017年第5期31卷 578-588页

作者： YANG Jing zhang da-hai CHEN Ying LIANG Hui TAN Ming LI Wei MA Xian-dong Ocean College Zhejiang University The State Key Laboratory of Fluid Power and Mechatronic Systems Zhejiang University Engineering Department Lancaster University

A novel floating pendulum wave energy converter （WEC） with the ability of tide adaptation is designed and presented in this paper. Aiming to a high efficiency, the buoy＇s hydrodynamic shape is optimized by enumeration and comparison. Furthermore, in order to keep the buoy＇s well-designed leading edge always facing the incoming wave straightly, a novel transmission mechanism is then adopted, which is called the tidal adaptation mechanism in this paper. Time domain numerical models of a floating pendulum WEC with or without tide adaptation mechanism are built to compare their performance on various water levels. When comparing these two WECs in terms of their average output based on the linear passive control strategy, the output power of WEC with the tide adaptation mechanism is much steadier with the change of the water level and always larger than that without the tide adaptation mechanism.

关键词： wave energy simulation model analysis tide adaptation

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Robust and Non-fragile H_∞ Control for a Class of Uncertain Jump Linear Systems

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自动化学报 2006年第3期32卷 438-443页

作者： KANG Yu XI Hong-Sheng zhang da-Li JI hai-Bo Department of Automation University of Science and Technology of China Hefei Anhui 230026

This paper describes the synthesis of robust and non-fragile H∞ state feedback controllers for a class of uncertain jump linear systems with Markovian jumping parameters and state multiplicative noises. Under the assumption of a complete access to the norm-bounds of the system uncertainties and controller gain variations, sufficient conditions on the existence of robust stochastic stability and γ-disturbance attenuation H∞ property are presented. A key feature of this scheme is that the gain matrices of controller are only based on It, the observed projection of the current regime rt.

关键词：鲁棒控制 Markovian过程跳跃参数稳定性

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Design of A Hydraulic Power Take-off System for the Wave Energy Device with An Inverse Pendulum

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China Ocean Engineering 2014年第2期28卷 283-292页

作者：张大海李伟赵海涛鲍经纬林勇刚 Ocean College Zhejiang University State Key Laboratory of Fluid Power Transmission and Control Zhejiang University Key Laboratory of Engineering Oceanography The Second Institute of OceanographySOA

This paper describes a dual-stroke acting hydraulic power take-off （PTO） system employed in the wave energy converter （WEC） with an inverse pendulum. The hydraulic PTO converts slow irregular reciprocating wave motions to relatively smooth, fast rotation of an electrical generator. The design of the hydraulic PTO system and its control are critical to maximize the generated power. A time domain simulation study and the laboratory experiment of the full-scale beach test are presented. The results of the simulation and laboratory experiments including their comparison at full-scale are also presented, which have validated the rationality of the design and the reliability of some key components of the prototype of the WEC with an inverse pendulum with the dual-stroke acting hydraulic PTO system.

关键词： simulation dual-stoke acting power take-off (PTO) laboratory experiment inverse pendulum wave energy converter

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用于在线签名认证的特征提取和个性化特征选择方法

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模式识别与人工智能 2009年第4期22卷 619-623页

作者：张大海汪增福中国科学技术大学自动化系合肥230027

提出一种在线签名认证中的特征提取和特征选择的方法.采用一种F-Tablet手写板采集签名数据.该手写板的特点是不仅可记录签名时的字形信息(x,y)序列,还可记录签名时的五维力信息(Fx,Fy,Fz,Mx,My)序列.从每个签名中提取3个等级共188个特征... 详细信息

提出一种在线签名认证中的特征提取和特征选择的方法.采用一种F-Tablet手写板采集签名数据.该手写板的特点是不仅可记录签名时的字形信息(x,y)序列,还可记录签名时的五维力信息(Fx,Fy,Fz,Mx,My)序列.从每个签名中提取3个等级共188个特征,接着定义特征重要性函数F,然后根据特征的重要性函数F的值对选取的188个特征进行排序,对F设不同的阈值就可完成不同的特征选择.在认证过程中使用SVM算法对选取的特征进行训练,然后用训练所得的模型进行验证.该方法的错误拒绝率为1.2%,错误接受率为3.7%.

关键词：在线签名认证特征提取特征选择特征重要性五维力支持向量机(SVM)

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基于多特征的在线签名认证方法

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模式识别与人工智能 2009年第6期22卷 903-907页

作者：张大海汪增福中国科学技术大学自动化系合肥230027

提出一种多特征的在线签名认证方法.该方法综合利用全局特征、笔段特征和签名的力序列和字形序列.采用一种F_Tablet手写板采集签名数据,该手写板可以记录签名时的字形序列和三维力序列.首先提取签名的全局特征,并定义特征重要性函数对... 详细信息

提出一种多特征的在线签名认证方法.该方法综合利用全局特征、笔段特征和签名的力序列和字形序列.采用一种F_Tablet手写板采集签名数据,该手写板可以记录签名时的字形序列和三维力序列.首先提取签名的全局特征,并定义特征重要性函数对特征进行选择,选取有利于正确区分真伪签名的个性全局特征,用基于概率的方法训练签名.接着将签名分段,提取每一笔段的笔段特征,建立基于笔段特征的隐马尔可夫模型.然后用动态时间规整的方法匹配签名的力信息和字形信息序列.最后综合利用多种特征来验证待测签名.该方法的等错误率为1.5%.

关键词：在线签名认证全局特征特征选择笔段特征三维力隐马尔可夫模型(HMM) 动态时间规整

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间谐波相序特性的研究

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中国电机工程学报 2005年第12期25卷 29-34页

作者：张大海徐文远山东大学电气工程学院山东省济南市250061

相序是三相电力系统中电压和电流的重要特性。为了认识间谐波的相序特性,文中以两种典型的间谐波源(变频驱动装置和电动机)为例,通过理论分析和实验探讨了它们产生的间谐波的相序。研究表明间谐波可以表现为正序或负序。但是间谐波的相... 详细信息

相序是三相电力系统中电压和电流的重要特性。为了认识间谐波的相序特性,文中以两种典型的间谐波源(变频驱动装置和电动机)为例,通过理论分析和实验探讨了它们产生的间谐波的相序。研究表明间谐波可以表现为正序或负序。但是间谐波的相序特性不同于谐波,同一频率的间谐波可以具有不同的相序。一般规律是:间谐波的相序与被调制的系统基波(或谐波)分量的相序相同。如果调制后得到的频率为负值,则间谐波信号的相序将变反,即由正序变负序或由负序变正序。文中的研究成果有助于深入认识间谐波的特性和发展间谐波仿真软件。

关键词：间谐波相序三相电力系统变频驱动装置谐波信号仿真软件研究成果电动机谐波源负序频率调制电流电压基波

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