After a brief review of studies on artificial boundaries in dynamic soil-structure interaction, a three-dimensional viscous-spring artificial boundary （VSAB） in the time domain is developed in this paper. First, the...After a brief review of studies on artificial boundaries in dynamic soil-structure interaction, a three-dimensional viscous-spring artificial boundary （VSAB） in the time domain is developed in this paper. First, the 3D VSAB equations in the normal and tangential directions are derived based on the elastic wave motion theory. Secondly, a numerical simulation technique of wave motion equations along with the VSAB condition in the time domain is studied. Finally, numerical examples of some classical elastic wave motion problems are presented and the results are compared with the associated theoretical solutions, demonstrating that high precision and adequate stability can be achieved by using the proposed 3D VSAB. The proposed 3D VSAB can be conveniently incorporated in the general finite element program, which is commonly used to study dynamic soil-structure interaction problems.展开更多
A time domain prediction of wave-induced ship motions by a Rankine panel method is investigated. Linear boundary conditions on free surface and mean wetted body surface are adopted, while the numerical damping method ...A time domain prediction of wave-induced ship motions by a Rankine panel method is investigated. Linear boundary conditions on free surface and mean wetted body surface are adopted, while the numerical damping method is used for the radiation conditions. The motions of two ships in regular head waves are computed by the present method. The related numerical results are compared with the experiment data and those from linear strip theory. The comparison shows satisfactory agreements for pitch and heave transfer functions.展开更多
In this paper, we consider the local time and the self-intersection local time for a bifractional Brownian motion, and the collision local time for two independent bifractional Brownian motions. We mainly prove the ex...In this paper, we consider the local time and the self-intersection local time for a bifractional Brownian motion, and the collision local time for two independent bifractional Brownian motions. We mainly prove the existence and smoothness of the self-intersection local time and the collision local time, through the strong local nondeterminism of bifractional Brownian motion, L2 convergence and Chaos expansion.展开更多
Let B^Hi,Ki ={ Bt^Hi,Ki, t ≥ 0}, i= 1, 2 be two independent bifractional Brownian motions with respective indices Hi ∈ （0, 1） and K∈ E （0, 1]. One of the main motivations of this paper is to investigate f0^Tδ...Let B^Hi,Ki ={ Bt^Hi,Ki, t ≥ 0}, i= 1, 2 be two independent bifractional Brownian motions with respective indices Hi ∈ （0, 1） and K∈ E （0, 1]. One of the main motivations of this paper is to investigate f0^Tδ（Bs^H1 ,K1 - the smoothness of the collision local time, introduced by Jiang and Wang in 2009, IT = f0^T δ（Bs^H1,K1）ds, T 〉 0, where 6 denotes the Dirac delta function. By an elementary method, we show that iT is smooth in the sense of the Meyer-Watanabe if and only if min{H-1K1, H2K2} 〈-1/3.展开更多
Recently,‘Liquid crystal display(LCD)vs.organic light-emitting diode(OLED)display:who wins?’has become a topic of heated debate.In this review,we perform a systematic and comparative study of these two flat panel di...Recently,‘Liquid crystal display(LCD)vs.organic light-emitting diode(OLED)display:who wins?’has become a topic of heated debate.In this review,we perform a systematic and comparative study of these two flat panel display technologies.First,we review recent advances in LCDs and OLEDs,including material development,device configuration and system integration.Next we analyze and compare their performances by six key display metrics:response time,contrast ratio,color gamut,lifetime,power efficiency,and panel flexibility.In this section,we focus on two key parameters:motion picture response time(MPRT)and ambient contrast ratio(ACR),which dramatically affect image quality in practical application scenarios.MPRT determines the image blur of a moving picture,and ACR governs the perceived image contrast under ambient lighting conditions.It is intriguing that LCD can achieve comparable or even slightly better MPRT and ACR than OLED,although its response time and contrast ratio are generally perceived to be much inferior to those of OLED.Finally,three future trends are highlighted,including high dynamic range,virtual reality/augmented reality and smart displays with versatile functions.展开更多
基金National Natural Science Foundation of ChinaUnder Grant No.50478014Special Funds for Major State Basic Research Project Under Grant No.2002CB412706Research Funds from National Civil Defense Oficce of Chinafor the Tenth Five-year Plan。
文摘After a brief review of studies on artificial boundaries in dynamic soil-structure interaction, a three-dimensional viscous-spring artificial boundary （VSAB） in the time domain is developed in this paper. First, the 3D VSAB equations in the normal and tangential directions are derived based on the elastic wave motion theory. Secondly, a numerical simulation technique of wave motion equations along with the VSAB condition in the time domain is studied. Finally, numerical examples of some classical elastic wave motion problems are presented and the results are compared with the associated theoretical solutions, demonstrating that high precision and adequate stability can be achieved by using the proposed 3D VSAB. The proposed 3D VSAB can be conveniently incorporated in the general finite element program, which is commonly used to study dynamic soil-structure interaction problems.
文摘A time domain prediction of wave-induced ship motions by a Rankine panel method is investigated. Linear boundary conditions on free surface and mean wetted body surface are adopted, while the numerical damping method is used for the radiation conditions. The motions of two ships in regular head waves are computed by the present method. The related numerical results are compared with the experiment data and those from linear strip theory. The comparison shows satisfactory agreements for pitch and heave transfer functions.
基金supported by National Natural Science Foundation of China (Grant No.10871103)
文摘In this paper, we consider the local time and the self-intersection local time for a bifractional Brownian motion, and the collision local time for two independent bifractional Brownian motions. We mainly prove the existence and smoothness of the self-intersection local time and the collision local time, through the strong local nondeterminism of bifractional Brownian motion, L2 convergence and Chaos expansion.
基金supported by National Natural Science Foundation of China (Grant No.10871041)Key Natural Science Foundation of Anhui Educational Committee (Grant No. KJ2011A139)
文摘Let B^Hi,Ki ={ Bt^Hi,Ki, t ≥ 0}, i= 1, 2 be two independent bifractional Brownian motions with respective indices Hi ∈ （0, 1） and K∈ E （0, 1]. One of the main motivations of this paper is to investigate f0^Tδ（Bs^H1 ,K1 - the smoothness of the collision local time, introduced by Jiang and Wang in 2009, IT = f0^T δ（Bs^H1,K1）ds, T 〉 0, where 6 denotes the Dirac delta function. By an elementary method, we show that iT is smooth in the sense of the Meyer-Watanabe if and only if min{H-1K1, H2K2} 〈-1/3.
基金AFOSR for partial financial support under contract No.FA9550-14-1-0279.
文摘Recently,‘Liquid crystal display(LCD)vs.organic light-emitting diode(OLED)display:who wins?’has become a topic of heated debate.In this review,we perform a systematic and comparative study of these two flat panel display technologies.First,we review recent advances in LCDs and OLEDs,including material development,device configuration and system integration.Next we analyze and compare their performances by six key display metrics:response time,contrast ratio,color gamut,lifetime,power efficiency,and panel flexibility.In this section,we focus on two key parameters:motion picture response time(MPRT)and ambient contrast ratio(ACR),which dramatically affect image quality in practical application scenarios.MPRT determines the image blur of a moving picture,and ACR governs the perceived image contrast under ambient lighting conditions.It is intriguing that LCD can achieve comparable or even slightly better MPRT and ACR than OLED,although its response time and contrast ratio are generally perceived to be much inferior to those of OLED.Finally,three future trends are highlighted,including high dynamic range,virtual reality/augmented reality and smart displays with versatile functions.
