Numerical studies for a model describing complexity

ＮＵＭＥＲＩＣＡＬＳＴＵＤＩＥＳＦＯＲＡＭＯＤＥＬＤＥＳＣＲＩＢＩＮＧＣＯＭＰＬＥＸＩＴＹＨｕａｎｇＸｉｎ（黄欣）ＬｉｕＺｅｎｇ－ｒｏｎｇ（刘曾荣）（Ｄｅｐｔ．ｏｆＭａｔｈ．ＳｕｚｈｏｕＵｎｉｖｅｒｓｉｔｙ,Ｓｕｚｈｏｕ,Ｊｉａｎｇｓｕ）（ＬＮＭ,Ｉ...     

A CONDENSED METHOD FOR LINEAR COMPLEMENTARY EQUATION OF ELASTO－PLASTIC PROBLEMS

ＡＣＯＮＤＥＮＳＥＤＭＥＴＨＯＤＦＯＲＬＩＮＥＡＲＣＯＭＰＬＥＭＥＮＴＡＲＹＥＱＵＡＴＩＯＮＳＯＦＥＬＡＳＴＯ－ＰＬＡＳＴＩＣＰＲＯＢＬＥＭＳＹｉｎＦｕｘｉｎ（殷福新），ＳｕｎＨｕａｎｃｈｕｎ（孙焕纯）（ＲｅｃｅｉｎｅｄＪｕｌｙ２５．１９９４）ＡＣＯ...     

Sampling formulae of higher order

ＳＡＭＰＬＩＮＧＦＯＲＭＵＬＡＥＯＦＨＩＧＨＥＲＯＲＤＥＲＣｈｅｎＤａ－ｄｕａｎ（陈达段）ＬｉｕＸｉａｏ－ｍｉｎｇ（刘晓明）（ＳｈａｎｇｈａｉＵｎｉｖｅｒｓｉｔｙ,Ｓｈａｎｇｈａｉ２０００７２）（ＲｅｃｅｉｖｅｄＪｕｌｙ３０．１９９４,Ｃｏｍｍｕｎｉ...     

TRANSFER OPEN OR CLOSED SETVALUED MAPPING AND GENERALIZ－ATION OF H－KKM THEOREM WITH APPLICATIONS

ＴＲＡＮＳＦＥＲＯＰＥＮＯＲＣＬＯＳＥＤＳＥＴＶＡＬＵＥＤＭＡＰＰＩＮＧＡＮＤＧＥＮＥＲＡＬＩＺ－ＡＴＩＯＮＯＦＨ－ＫＫＭＴＨＥＯＲＥＭＷＩＴＨＡＰＰＬＩＣＡＴＩＯＮＳＬｉＢｉｎｇ－ｙｏｕ（李秉友）;ＳｕＪｉａ－ｂａｏ（苏家宝）（Ｄｅｐａｒｔｍｅｎｔ...     

INVARIANT MANIFOLDS AND THEIR STABILITY IN A THREE－DIMENSIONAL MEASURE－PRESERVING MAPPING SYSTEMS

ＩＮＶＡＲＩＡＮＴＭＡＮＩＦＯＬＤＳＡＮＤＴＨＥＩＲＳＴＡＢＩＬＩＴＹＩＮＡＴＨＲＥＥ－ＤＩＭＥＮＳＩＯＮＡＬＭＥＡＳＵＲＥ－ＰＲＥＳＥＲＶＩＮＧＭＡＰＰＩＮＧＳＹＳＴＥＭＳＬｉｕＪｉｅ（刘杰）（ＲｅｃｅｉｖｅｄＤｅｃ．１．１９９４;Ｃｏｍｍｕｎｉｃ...     

（Φ，△）－TYPE PROBABILISTIC CONTRACTOR AND SOLUTIONS FOR A NONLINEAR OPERATOR EQUATIONS IN MENGER PN－SPACES

（Φ，△）－ＴＹＰＥＰＲＯＢＡＢＩＬＩＳＴＩＣＣＯＮＴＲＡＣＴＯＲＡＮＤＳＯＬＵＴＩＯＮＳＦＯＲＡＮＯＮＬＩＮＥＡＲＯＰＥＲＡＴＯＲＥＱＵＡＴＩＯＮＳＩＮＭＥＮＧＥＲＰＮ－ＳＰＡＣＥＳ￥ＦａｎｇＪｉｎｘｕａｎ（方锦暄）（ＤｅｐａｒｔｍｅｎｔｏｆＭａｔ...     

ELEMENT－BY－ELEMENT MATRIX DECOMPOSITION ANDSTEP－BY－STEP INTEGRATION METHOD FOR TRANSIENTDYNAMIC PROBLEMS

ＥＬＥＭＥＮＴ－ＢＹ－ＥＬＥＭＥＮＴＭＡＴＲＩＸＤＥＣＯＭＰＯＳＩＴＩＯＮＡＮＤＳＴＥＰ－ＢＹ－ＳＴＥＰＩＮＴＥＧＲＡＴＩＯＮＭＥＴＨＯＤＦＯＲＴＲＡＮＳＩＥＮＴＤＹＮＡＭＩＣＰＲＯＢＬＥＭＳＷａｎｇＨｕａｉｚｈｏｎｇ（王怀忠）（ＲｅｃｅｉｖｅｄＪｕ...     

PRINCIPAL AXIS INTRINSIC METHOD AND THE HIGH DIMENSIONAL TENSOR EQUATION AX－XA＝C

ＰＲＩＮＣＩＰＡＬＡＸＩＳＩＮＴＲＩＮＳＩＣＭＥＴＨＯＤＡＮＤＴＨＥＨＩＧＨＤＩＭＥＮＳＩＯＮＡＬＴＥＮＳＯＲＥＱＵＡＴＩＯＮＡＸ－ＸＡ＝ＣＬｉａｎｇＨａｏｙｕｎ（梁浩云）（ＷｕｙｉＵｎｉｖｅｒｓｉｔｙ，Ｊｉａｎｇｍｅｎ５２９０２０，Ｐ．Ｒ．Ｃｈｉｎ...     

On completeness for a 3-D linear theory of composite laminate

ＯＮＣＯＭＰＬＥＴＥＮＥＳＳＦＯＲＡ３－ＤＬＩＮＥＡＲＴＨＥＯＲＹＯＦＣＯＭＰＯＳＩＴＥＬＡＭＩＮＡＴＥＪｉａｎｇＹｏｕ－ｌｉａｎｇ（蒋友谅）（ＤｅｐａｒｔｍｅｎｔｏｆＡｐｐｌｉｅｄＭｅｃｈａｎｉｅｓ．ＰｅｋｉｎｇＩｎｓｔｉｔｕｔｅｏｆＴｅｃｈｎｏｌ...     

THE BOUNDED EXTERMINATION AND STABILITY OF MUTUAL INTERFERENCE SYSTEM OF FOUR－DIMENSIONAL SPECIES

ＴＨＥＢＯＵＮＤＥＤＥＸＴＥＲＭＩＮＡＴＩＯＮＡＮＤＳＴＡＢＩＬＩＴＹＯＦＭＵＴＵＡＬＩＮＴＥＲＦＥＲＥＮＣＥＳＹＳＴＥＭＯＦＦＯＵＲ－ＤＩＭＥＮＳＩＯＮＡＬＳＰＥＣＩＥＳＨｏｕＧａｎ－ｓｈｅｎｇ（侯赣生）（Ｄｅｐｌ．ｏｆＰｈｙｓｉｃｓ,Ｊｉａｎｇｘ...     

A COMPARATIVE STUDY OF THE OPENING AND CLOSING PROCESS OF TWO TYPES OF MECHANICAL HEART VALVES USING ALE FINITE ELEMENT METHOD

ＡＣＯＭＰＡＲＡＴＩＶＥＳＴＵＤＹＯＦＴＨＥＯＰＥＮＩＮＧＡＮＤＣＬＯＳＩＮＧＰＲＯＣＥＳＳＯＦＴＷＯＴＹＰＥＳＯＦＭＥＣＨＡＮＩＣＡＬＨＥＡＲＴＶＡＬＶＥＳＵＳＩＮＧＡＬＥＦＩＮＩＴＥＥＬＥＭＥＮＴＭＥＴＨＯＤＡＣＯＭＰＡＲＡＴＩＶＥＳＴＵＤＹＯＦ...     

ALE FINITE ELEMENT ANALYSIS OF THE OPENING AND CLOSING PROCESS OF THE ARTIFICIAL MECHANICAL VALVE

ＡＬＥＦＩＮＩＴＥＥＬＥＭＥＮＴＡＮＡＬＹＳＩＳＯＦＴＨＥＯＰＥＮＩＮＧＡＮＤＣＬＯＳＩＮＧＰＲＯＣＥＳＳＯＦＴＨＥＡＲＴＩＦＩＣＩＡＬＭＥＣＨＡＮＩＣＡＬＶＡＬＶＥ（张建海）（陈大鹏）（邹盛铨）ＡＬＥＦＩＮＩＴＥＥＬＥＭＥＮＴＡＮＡＬＹＳＩＳＯＦＴ...     

改进的特征线方法及过载对水锤效应影响分析

传统特征线方法对过载作用下的水锤计算具有局限性，无法为水锤防护提供可靠性指导。本文在考虑过载效应和动态摩阻的基础上，提出了改进的特征线方法，该方法能准确模拟过载作用下水锤最大压力峰值及水锤波的衰减特性。基于该方法，建立了过载作用下水锤效应数学模型，通过分析结果与CFD数值仿真及实验数据对比，验证了改进特征线方法的正确性。分析结果表明，在恒定过载作用时，阀门位置的流体压力随过载量的增加而增大，且管轴向过载的影响大于横向过载；关阀过程受到瞬时过载作用时，过载效应对水锤最大压力峰值影响显著，而对关阀后水锤波的传播和衰减影响较小；同时，分析了过载效应下关阀特性和流体密度等参数对水锤效应的影响规律。     

主动脉瓣倾斜角度血流动力学的 PIV 实验研究

瓣叶血栓是主动脉瓣置换术后典型的继发性瓣膜疾病,血流动力学特征异常在其发展过程中至关重要.本文利用粒子图像测速 (particle image velocimetry,PIV) 系统,实验研究了主动脉瓣开口纵向轴线与升主动脉纵向轴线之间倾斜角度 ($\alpha =0^\circ$, $\alpha=5^\circ$,$\alpha =10^\circ$ 和 $\alpha =15^\circ$) 对速度、涡度和黏性剪应力分布等血流动力学特性的影响.研究结果表明:当 $\alpha =0^\circ$ 时,主动脉根部跨瓣血液流动为中心对称流动,而 $\alpha =5^\circ$,$\alpha=10^\circ$ 和 $\alpha =15^\circ$ 时跨瓣血液流动向升主动脉的左冠状动脉一侧倾斜.随着倾斜角度增大,跨瓣血液流动方向倾斜程度增加,血液流动冲击升主动脉壁,损伤内皮细胞导致血栓形成.主动脉瓣倾斜时主动脉窦血液流动速度增大,涡旋也更向主动脉窦底部运动,不利于血液从冠状动脉口流出向心肌供血.同时,主动脉根部的高涡度和高黏性剪应力区域也向升主动脉的左冠状动脉一侧倾斜,主动脉窦的高涡度区域位于主动脉窦底部、高黏性剪应力区域分布于主动脉窦壁面处.主动脉瓣存在倾斜角度时,涡度和黏性剪应力较大,特别是 $\alpha =10^\circ$ 和 $\alpha=15^\circ$,为血栓形成提供了有利环境.研究结果可为临床主动脉瓣置换术参数选择以及继发性瓣膜疾病的避免提供理论依据和技术参考.      

Study of the closing mechanism of natural heart valves

At present, there are still some controversial considerations on the closing mechanismof natural heart valves. In this area. a lot of phenomena still remain mysterious.particularlyfor the mechanism of earlier partial closure of the valve white the blood ejection is still in itsacceleration phase. It is the purpose of this study to focus on the problem of earlier closuremechanism of heart valves by using both theoretical analysis and experimentalverifications. A certain two-dimensional mathematical model of closure with allcontributing factors and the whole operating process being considered is investigated with anew analytical method Several new conclusions were found. The main points are asfollows:I. During the opening phase, the main factor of motion of the valve is the acceleratingflow, and the decelerating flow plays a main role during most the of time of the decelerationphase. But during the quasi-steady phase of blood ejection. it is the vortex in the sinus thatcontrols the valve closure.2. For Ih     

PIV EXPERIMENTAL STUDY ON THE HEMODYNAMICS OF AORTIC VALVE UNDER VARIED TILTED ANGLES 1)

瓣叶血栓是主动脉瓣置换术后典型的继发性瓣膜疾病,血流动力学特征异常在其发展过程中至关重要.本文利用粒子图像测速 (particle image velocimetry,PIV) 系统,实验研究了主动脉瓣开口纵向轴线与升主动脉纵向轴线之间倾斜角度 ($\alpha =0^\circ$, $\alpha=5^\circ$,$\alpha =10^\circ$ 和 $\alpha =15^\circ$) 对速度、涡度和黏性剪应力分布等血流动力学特性的影响.研究结果表明：当 $\alpha =0^\circ$ 时,主动脉根部跨瓣血液流动为中心对称流动,而 $\alpha =5^\circ$,$\alpha=10^\circ$ 和 $\alpha =15^\circ$ 时跨瓣血液流动向升主动脉的左冠状动脉一侧倾斜.随着倾斜角度增大,跨瓣血液流动方向倾斜程度增加,血液流动冲击升主动脉壁,损伤内皮细胞导致血栓形成.主动脉瓣倾斜时主动脉窦血液流动速度增大,涡旋也更向主动脉窦底部运动,不利于血液从冠状动脉口流出向心肌供血.同时,主动脉根部的高涡度和高黏性剪应力区域也向升主动脉的左冠状动脉一侧倾斜,主动脉窦的高涡度区域位于主动脉窦底部、高黏性剪应力区域分布于主动脉窦壁面处.主动脉瓣存在倾斜角度时,涡度和黏性剪应力较大,特别是 $\alpha =10^\circ$ 和 $\alpha=15^\circ$,为血栓形成提供了有利环境.研究结果可为临床主动脉瓣置换术参数选择以及继发性瓣膜疾病的避免提供理论依据和技术参考.     

Development of a novel passive top–down uniflow scavenged two-stroke GDI engine

The design and performance characteristics of a novel top–down uniflow scavenged gasoline direct-injection two-stroke engine are presented. The novelty of the engine lies in the cylinder head that contains multiple check valves that control scavenging airflow into the cylinder from a supercharged air plenum. When the cylinder pressure drops below the intake plenum pressure during the expansion stroke, air flows into the cylinder through the check valves. During compression the cylinder pressure increases to a level above the intake plenum pressure and the check valves close preventing back-flow into the intake plenum. The engine head design provides asymmetrical intake valve timing without the use of poppet valves and the associated valve-train. In combination with an external Roots-type supercharger that supplies the plenum and exhaust ports at the bottom of the cylinder wall, the novel head provides top–down uniflow air scavenging. Motoring tests indicated that the check valves seal and the peak pressure is governed by the compression ratio. The only drawback observed is that valve closing is delayed as the engine speed increases. In order to investigate the valve dynamics, additional tests were performed in an optically-accessible cold flow test rig that enabled the direct measurement of valve opening and closing time under various conditions.     

含微裂纹弹性体的应力应变关系

本义建立了考虑裂纹闭合和裂纹表面摩擦影响的含微裂纹弹性体的应力应变关系，给出了柔度张量增量的显式表达式。对于二维平面应力和平面应变状态，给出了等效工程弹性系数。数值计算结果表明，裂纹闭合和裂纹面摩擦对裂纹体的应力应变关系和等效工程弹性系数有重要影响。     

含微裂纹弹性体的应力应变关系

本义建立了考虑裂纹闭合和裂纹表面摩擦影响的含微裂纹弹性体的应力应变关系，给出了柔度张量增量的显式表达式。对于二维平面应力和平面应变状态，给出了等效工程弹性系数。数值计算结果表明，裂纹闭合和裂纹面摩擦对裂纹体的应力应变关系和等效工程弹性系数有重要影响。