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51.
Zhengjun Liu Lie XuChuang Lin Jingmin DaiShutian Liu 《Optics and Lasers in Engineering》2011,49(4):542-546
An image encryption is discussed based on the random phase encoding method in gyrator domains. An iterative structure of image encryption is designed for introducing more random phases to encrypt image. These random phase functions are generated by a two-dimensional chaotic mapping with the help of computer. The random phases are utilized for increasing the security of this encryption algorithm. In the chaotic mapping relation, the initial value and expression can serve as the key of algorithm. The mapping relation is considered secretly for storage and transmission in practical application in comparison to traditional algorithms. The angle parameter of gyrator transform is an additional key. Some numerical simulations have been given to validate the performance of the encryption scheme. 相似文献
52.
The TS-1 film on tubular mullite support was prepared by secondary growth via template-free route using tetraethyl orthosilicate (TEOS) and tetrabutyl orthotitanate (TBOT) as silica and titanium sources. The as-made films were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and ultraviolet-visible spectroscopy (UV-vis). Continuous TS-1 seed layer was bonded tightly to the mullite substrates. After secondary growth in the template-free synthesis solution, intergrown TS-1 zeolite film with the typical MFI-type structure was formed on the outer surface of support. The Si atoms in zeolitic lattice were found to be isomorphously substituted by Ti atoms which existed only in tetrahedral coordination. The thickness of the obtained TS-1 zeolite film was less than 20 μm. 相似文献
53.
用 R T P C R技术从 C S F V H C L V 株 F482 代感染兔脾的细胞总 R N A 中分段扩增出了 C S F V E2 基因特异的3 个部分重叠的 D N A 片段(大小分别为 499 bp、572 bp 和 245 bp),并将之分别克隆到p G E M T 载体上 经核苷酸序列测定和片段重叠完成了包含 E2 全长基因的 1 144 bp 序列的测定,其 G C含量为49.0% :核苷酸序列与国外报道的各株病毒的 E2 基因同源性分别为83.5% ~97.5% ;其推导的氨基酸序列的同源性也分别为89.3%~96.2% ,变异主要分布在 E2 蛋白的 N 半部分 相似文献
54.
The Kadomtsev-Petviashvili equation describes nonlinear dispersive waves which travel mainly in one direction, generalizing the Korteweg-de Vries equation for purely uni-directional waves. In this Letter we derive an improved KP-equation that has exact dispersion in the main propagation direction and that is accurate in second order of the wave height. Moreover, different from the KP-equation, this new equation is also valid for waves on deep water. These properties are inherited from the AB-equation (E. van Groesen, Andonowati, 2007 [1]) which is the unidirectional improvement of the KdV equation. The derivation of the equation uses the variational formulation of surface water waves, and inherits the basic Hamiltonian structure. 相似文献
55.
56.
Examples are presented of Doppler broadening measurements on singlet, doublet and triplet emission spectra from the following impurity ions found in the boundary layer of the TEXTOR tokamak: Cii, Ciii, Civ, Siii, and Siiii. The shapes of these spectral lines are significantly influenced by the confining magnetic field of some 2T, in some cases exhibiting an appreciable Paschen-Back effect which complicates their appearance. It is shown that reliable values for the particular ion temperature can be obtained from the Doppler widths of the various Zeeman components, when the presence of the magnetic field is properly accounted for. Such temperatures derived from partially ionised impurity species should, however, be cautiously interpreted, as the ions in question probably do not exist for long enough in the particular ionisation stage to achieve thermal equilibrium with the background deuterons and protons. This interpretation of our results is supported by a simple one-dimensional model of ionisation and collisional heating processes in the plasma boundary. 相似文献
57.
58.
本文以分析变深度螺旋槽止推轴承为例介绍了边界元法在润滑力学研究领域中的应用,以及相应的边界条件的处理方法,同时还讨论了轴承的尺寸参数对其性能参数的影响。 相似文献
59.
球形封闭容器内一个简单的煤粉燃烧爆炸模型 总被引:1,自引:0,他引:1
在分析了大量球形封闭容器内煤粉燃烧爆炸实验数据基础上,考虑了煤粉燃烧爆炸机理所涉及的湍流燃烧、相变、各种化学反应动力学过程等复杂因素,并且对球形封闭容器内由于煤粉混合不均匀造成的燃烧不充分给予了考虑,得到了球形封闭容器内煤粉燃烧爆炸特征的数值计算结果,计算的压力-时间曲线与实验结果符合较好。 相似文献
60.
Sebastian T. Le QuementMette Ishoey Mette T. PetersenPernille M. Simonsen Nanna S. HolckThomas E. Nielsen 《Tetrahedron letters》2011,52(52):7049-7053
An approach for the solid-phase synthesis of apoptosis-inducing Smac peptidomimetics is presented. Using a Rink linker strategy, tetrapeptides mimicking the N-4-terminal residue of the Smac protein [(N-Me)AVPF sequence] were synthesized on PEGA resin in excellent purities and yields. Following two synthetic routes, a known tetrapeptide, incorporating a substituted proline, previously shown to exhibit excellent biological activity in vitro as well as low toxicity, was synthesized effectively on a solid support. 相似文献