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41.
In this paper, we continue our investigation of polyharmonic mappings in the complex plane. First, we establish two Landau type theorems. We also show a three circles type theorem and an area version of the Schwarz lemma. Finally, we study Lipschitz continuity of polyharmonic mappings with respect to the distance ratio metric. 相似文献
42.
43.
将遥感技术应用到测绘当中是现代地质测绘技术的发展趋势,随着光学载荷分辨率的不断提高,遥感测绘已经成为社会发展和国民经济发展的重要保障。光学载荷决定了测绘空间遥感器的分辨率、测绘精度、卫星平台体积与重量,是遥感器的核心部分。本文对高成像质量透射光学系统、同轴三反光学系统、离轴三反系统等常用的空间遥感测绘光学系统的结构形式和光学性能分别进行了介绍,并对处于研发阶段的新型空间反射光学系统的结构形式和光学性能进行了展望。分析认为,根据不同的应用环境和技术指标,合理选用不同种类的遥感测绘光学系统,可以最大程度利用平台资源,满足遥感测绘需求。 相似文献
44.
Nazia Noor Joachim Koll Maryam Radjabian Clarissa Abetz Volker Abetz 《Macromolecular rapid communications》2016,37(5):414-419
A double‐layer hollow fiber is fabricated where an isoporous surface of polystyrene‐block‐poly(4‐vinylpyridine) is fixed on a support layer by co‐extrusion. Due to the sulfonation of the support layer material, delamination of the two layers is suppressed without increasing the number of subsequent processing steps for isoporous composite membrane formation. Electron microscope‐energy‐dispersive X‐ray spectroscopy images unveil the existence of a high sulfur concentration in the interfacial region by which in‐process H‐bond formation between the layers is evidenced. For the very first time, our study reports a facile method to fabricate a sturdy isoporous double‐layer hollow fiber.
45.
Turbulent drag reduction experienced by ribletted surfaces is the result of both (1) the interaction between riblet peaks and the coherent structures that characterize turbulent near-wall flows, and (2) the laminar sublayer flow modifications caused by the riblet shape, which can balance, under appropriate conditions, the drag penalty due to the increased wetted surface. The latter “viscous” mechanism is investigated by means of an analytical model of the laminar sublayer, which removes geometrical restrictions and allows us to take into account “real” shapes of riblet contours, affected by manufacturing inaccuracies, and to compute even for such cases a parameter, called protrusion height, related to the longitudinal mean flow. By considering real geometries, riblet effectiveness is clearly shown to be related to the difference between the longitudinal and the transversal protrusion heights. A simple method for the prediction of the performances of ribletted surfaces is then devised. The predicted and measured drag reduction data, for different riblet geometries and flow characteristics, are in close agreement with each other. The soundness of the physical interpretation underlying this prediction method is consequently confirmed. 相似文献
46.
A new model shift mapping was given in bilateral symbol space. It is topologically conjugate with the traditional shift mapping. Similar to Smale Horseshoe, a model was constructed correspondent to the model shift mapping, i.e., a class of mapping on Mbius strip was given. Its attractors’ structure and dynamical behaviour were described. 相似文献
47.
A GEOMETRIC THEORY IN INVESTIGATION ON MODE LOCALIZATION AND FREQUENCY LOCI VEERING PHENOMENA 总被引:1,自引:0,他引:1
Liu Jike Zhao Lingcheng Fang Tong 《Acta Mechanica Solida Sinica》1995,8(4):349-355
According to the mapping theory in complex plane,the geometric features of eigen fre-quency loci of systems undergoing free vibrations are investigated.It is concluded that the phenomenaof curve coalescence and veering can be described in a unified manner from the singularities of map-ping from the complex parameter plane onto the complex frequency plane.The formation of a branchpoint in the parameter space is the foundation of explaining localization and veering phenornena.Bythe use of condensation to reduce the dimension of a system,the scope of application of the geometrictheory is widely expanded.The theory is applied to examples to verify the validity of the proposed ap-proach.The present work is an improvement and extension of recent work by M.S.Traintafyllou etal., 相似文献
48.
由Hsu提出的利用胞映射进行最优控制的方法可以发展成实用的工程控制技术.本文以研究算法为出发点,利用胞映射的特性,结合实际的计算与可能,作了一系列旨在提高计算速度和节省内存的改进;并给出了简单有效的区分同耗最优控制对的统一的方法.使用平常的微型计算机也能有效地解决实际工程问题的最优控制. 相似文献
49.
非线性粘弹性梁在随动载荷作用下的混沌运动 总被引:2,自引:0,他引:2
计及材料的非线性弹性和粘性性质,研究了悬臂梁在自由端受随动载荷作用时的混沌运动,导出了相应的非线性动力方程,利用Melnikov函数法,结合Poincare映射、相平面轨迹和时程曲线判定系统是否处于混沌状态,并对系统通向混沌的道路进行了讨论. 相似文献
50.
云天铨 《应用数学和力学(英文版)》2001,22(10):1132-1139
IntroductionManystudieshavebeendoneoncontractivemappings,e .g .,Rhoades[1]madeacomparisonofvariousdefinitions (morethan 1 0 0typesvariedfrom 2 5basictypes)ofcontractivemappingoncompletemetricspacein 1 977.Anduptonow ,suchstudyisstillgoingon ,e .g .,[2 ] .Inthispaper,these… 相似文献