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1.
The numerical solution of Dirichlet's problem for a second-orderelliptic operator in divergence form with arbitrary nonlinearitiesin the first- and zero-order terms is considered. The mixedfinite-element method is used. Existence and uniqueness of theapproximation are proved and optimal error estimates in L2 aredemonstrated for the relevant functions. Error estimates arealso derived in Lq, 2q+ 相似文献
2.
燃气流量低频脉动下的火焰结构特征 总被引:1,自引:0,他引:1
针对一种可降低天然气高温燃烧过程中NOx生成量的脉动供燃料燃烧技术,研究了一个采用燃气流量脉动燃烧方式的射流扩散火焰。采用纹影和直接摄像手段观察了在燃气流量低频率(10Hz以下)脉动工况下的火焰特征及其变化,分析了火焰长度脉动特征和火焰内部结构的周期发展过程。研究发现:火焰内部结构的周期发展过程包括高速(波峰流量)燃气脉冲冲出、增长、燃气惯性冲出、回吸、低速(波谷流量)和高速燃气脉冲的分离、低速脉冲的增长等阶段。其中低速和高速燃气脉冲的分离是单火焰燃烧不稳定的原因。 相似文献
3.
阐述一种LQR控制器设计的新方法。根据哈密尔顿系统理论,深入研究了系统特征方程的闭环极点和加权矩阵的关系,给出了希望加权矩阵的确定方法。通过Matlab仿真实验,证明了根据极点的移动范围来确定LQR控制器的方法是可行的。 相似文献
4.
ABSTRACT Superporous hydrogels, hydrogels with pore sizes in the range of 100 μm and larger, were synthesized using N-isopropyl-acrylamide (NIPAM) and acrylamide (AM). The superporous hydrogels were synthesized by crosslinking polymerization of monomers in the presence of gas bubbles. The pores of superporous hydrogels were connected to each other to form open capillary channels, which provided fast response to the changes in the environmental temperature. Upon increase in temperature from 10°C to 65°C, the superporous hydrogel made from a monomer solution of NIPAM:AM = 9:1 shrank from the fully swollen state (volume of 36 cm3) to the fully collapsed state (volume of 6.5 cm3) in 72±14 sec. When the temperature was changed back to 10°C, the superporous hydrogel swelled to 36 cm3 in 78±15 sec. This deswelling-swelling cycle was repeated many times without changes in the thermo-reversible property of the superporous hydrogel. The response time of the superporous hydrogels was thousand times faster than that of conventional hydrogels. The fast response of the superporous hydrogels is due to the rapid uptake or exclusion of water molecules through the extensive capillary channels. Because superporous hydrogels still maintain the open capillary structure even after drying, the dried superporous hydrogels can also swell to the equilibrium swelling state within minutes. These fast responsive hydrogels can find many pharmaceutical and medical applications. 相似文献
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Hanchul PARK 《数学年刊B辑(英文版)》2017,38(6):1321-1334
This paper deals with two things.First,the cohomology of canonical extensions of real topological toric manifolds is computed when coefficient ring G is a commutative ring in which 2 is unit in G.Second,the author focuses on a specific canonical extensions called doublings and presents their various properties.They include existence of infinitely many real topological toric manifolds admitting complex structures,and a way to construct infinitely many real toric manifolds which have an odd torsion in their cohomology groups.Moreover,some questions about real topological toric manifolds related to Halperin's toral rank conjecture are presented. 相似文献
7.
Sun-Hye PARK 《数学物理学报(B辑英文版)》2017,37(4):965-973
In this paper, we consider a von Karman equation with infinite memory. For von Karman equations with finite memory, there is a lot of literature concerning on existence of the solutions, decay of the energy, and existence of the attractors. However, there are few results on existence and energy decay rate of the solutions for von Karman equations with infinite memory. The main goal of the present paper is to generalize previous results by treating infinite history instead of finite history. 相似文献
8.
AHN Yang-Keun PARK Young-Choong CHOI Kwang-Soon PARK Woo-Chool SEO Hae-Moon JUNG Kwang-Mo 《重庆邮电大学学报(自然科学版)》2009,21(2):222-227
Recently developed timeofflight principle based depthsensing video camera technologies provide precise perpixel range data in addition to color video. Such cameras will find application in robotics and visionbased human computer interaction scenarios such as games and gesture input systems. Timeofflight principle range cameras are becoming more and more available. They promise to make the 3D reconstruction of scenes easier, avoiding the practical issues resulting from 3D imaging techniques based on triangulation or disparity estimation. A spatial touch system was presented which uses a depthsensing camera to touch spatial objects and details on its implementation, and how this technology will enable new spatial interactions was speculated. 相似文献
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Optical Properties of Zinc-Blende InGaN/GaN Quantum Well Structures and Comparison with Experiment 下载免费PDF全文
Optical properties of zinc-blende InGaN/GaN Q W structures are investigated using the multiband effective-mass theory. The transition wavelength values at 300 K ranged from 440 to 570nm in the investigated range of the In composition and the well width. The theoretical wavelengths show reasonable agreement with the experimental results. The optical gain decreases with the increasing well width. This is mainly due to the reduction in the quasi-Fermi-level separation because the optical matrix element increases with the well width. 相似文献