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31.
32.
Liondas CA; Chrissoulidis DP 《The Quarterly Journal of Mechanics and Applied Mathematics》2007,60(3):275-287
This paper is intended to clarify a misunderstanding concerningthe source singularity of the electric Green's tensor for aperfectly conducting semi-infinite cone of circular cross-section.Tai's series expansion of the Green's tensor is known to lacka singular term at the source region. Jones has reconstructedthe solution to this problem and has pointed out the differencebetween his result and that of Tai. The aim of our paper isto demonstrate that, although Jones's closed-form solution iscorrect, there is a mistake in his comparison with Tai's seriessolution. We conclude that one of the two additional singularterms that Jones claims as missing from Tai's formula must beomitted. Besides, we compare Jones's closed-form solution withSmyshlyaev's solution to the very same problem. We concludethat the magnetic field expressions given by Jones and Smyshlyaevcoincide, but a singular term is missing from Smyshlyaev's expressionfor the electric field. 相似文献
33.
Goodman TNT; Micchelli CA; Rodriguez G; Seatzu S 《IMA Journal of Numerical Analysis》1998,18(3):331-354
It is shown that, under certain conditions, orthonormalizingthe positive integer shifts of an exponentially decaying functionon the half line by the Gram-Schmidt process leads to a limitingprofile given by orthonormalizing all their integer shifts onthe whole line. These results derive from properties of Choleskyfactorization of bi-infinite and semi-infinite matrices. Anexample is provided by the negative exponential function andconjectures are given, supported by numerical evidence, forthe Gaussian and Lorentz function. 相似文献
34.
35.
Shunzhi Wang William Morris Yangyang Liu C. Michael McGuirk Yu Zhou Prof. Joseph T. Hupp Prof. Omar K. Farha Prof. Chad A. Mirkin 《Angewandte Chemie (International ed. in English)》2015,54(49):14738-14742
A method for modifying the external surfaces of a series of nanoscale metal–organic frameworks (MOFs) with 1,2‐dioleoyl‐sn‐glycero‐3‐phosphate (DOPA) is presented. A series of zirconium‐based nanoMOFs of the same topology (UiO‐66, UiO‐67, and BUT‐30) were synthesized, isolated as aggregates, and then conjugated with DOPA to create stably dispersed colloids. BET surface area analysis revealed that these structures maintain their porosity after surface functionalization, providing evidence that DOPA functionalization only occurs on the external surface. Additionally, dye‐labeled ligand loading studies revealed that the density of DOPA on the surface of the nanoscale MOF correlates to the density of metal nodes on the surface of each MOF. Importantly, the surface modification strategy described will allow for the general and divergent synthesis and study of a wide variety of nanoscale MOFs as stable colloidal materials. 相似文献
36.
Langille MR Personick ML Zhang J Mirkin CA 《Journal of the American Chemical Society》2011,133(27):10414-10417
Gold octahedra with hollow features have been synthesized in high yield via the controlled overgrowth of preformed concave cube seeds. This Ag(+)-assisted, seed-mediated synthesis allows for the average edge length of the octahedra and the size of the hollow features to be independently controlled. We propose that a high concentration of Ag(+) stabilizes the {111} facets of the octahedra through underpotential deposition while the rate of Au(+) reduction controls the dimensions of the hollow features. This synthesis represents a highly controllable bottom-up approach for the preparation of hollow gold nanostructures. 相似文献
37.
Mirkin MV Nogala W Velmurugan J Wang Y 《Physical chemistry chemical physics : PCCP》2011,13(48):21196-21212
This Perspective is an update to our more extensive survey of scanning electrochemical microscopy (SECM) published in 2007. During this time, the SECM field retained its momentum by expanding into new areas and meeting the emerging scientific and technological challenges. Here we focus on most prominent developments such as high-resolution imaging, investigation of structures and processes on the nanoscale, alternative energy applications, and new approaches to solving "real world" problems. The fabrication of novel SECM probes and related theoretical advances are also discussed. 相似文献
38.
从烟草(品种革新一号)单倍体花粉植株的叶和茎产生的愈伤组织,结合悬浮培养,获得的细胞分离出原生质体。在液体培养基中静置培养,12小时后原生质体开始变为卵圆形,细胞壁明显可见,24小时后完成第一次细胞分裂。以后继续分裂形成浅黄色的愈伤组织,在培养四星期后可达1毫米大小,再放到转床上进行旋转培养18天左右,愈伤组织可达3—4毫米大小。当转移到分化培养基后,分别分化出苗及根,长成完整的植株。 原生质体再生细胞的分裂与分化,不仅受不同器官来源的愈伤组织及其年龄的影响;还受分化培养基的基本成份及所用细胞分裂素的类型等的影响。 相似文献
39.
本文利用中心流面法的概念,指出叶轮机械的设计白变数在内、外环壁面上应有附加的限制条件,并导得其具体简明方程。同时,还定性地分析了S1流面的翘曲情况。 相似文献
40.
本文求出了Eliashberg方程在T=Tc时的解,得到了下面的临界温度级数表示式: 其中α0(μ*),α1(μ*)等系数是μ*的函数.此式表明,Tc不仅依赖于λ,〈ω2〉和μ*,而且依赖于有效声子谱α2F(ω)的各级矩〈ω2n〉.这是区别于前人的Tc公式最重要的一点。这说明像McMillan以及Allen和Dynes的Tc公式不仅是近似的,而主要是他们没有能正确地概括出α2F(ω)对Tc的影响. 相似文献