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排序方式: 共有249条查询结果,搜索用时 11 毫秒
31.
A method to prepare 1H-indole-2-carbaldehydes and (E)-2-(iodomethylene)indolin-3-ols by gold(I)-catalyzed cycloisomerization of 1-(2-(tosylamino)phenyl)prop-2-yn-1-ols with N-iodosuccinimide (NIS) is reported. The reactions were shown to be operationally simplistic and proceed efficiently for a wide variety of substrates, affording the corresponding products in good to excellent yields (70-99%). The mechanism is suggested to involve activation of the alkyne moiety of the substrate by the gold(I) catalyst. This triggers intramolecular addition of the tethered aniline moiety to give a vinyl gold intermediate, which undergoes iododeauration with NIS to give the (E)-2-(iodomethylene)indolin-3-ol adduct. Subsequent 1,3-allylic alcohol isomerization (1,3-AAI) followed by formylation of this vinyl iodide intermediate then gives the 1H-indole-2-carbaldehyde. 相似文献
32.
H Kobayashi H Morita M Yamauchi R Ikeda H Kitagawa Y Kubota K Kato M Takata S Toh S Matsumura 《Journal of the American Chemical Society》2012,134(30):12390-12393
We have synthesized and characterized homogeneous solid-solution alloy nanoparticles of Pd and Rh, which are immiscible with each other in the equilibrium bulk state at around room temperature. The Pd-Rh alloy nanoparticles can absorb hydrogen at ambient pressure and the hydrogen pressure of Pd-Rh alloys for hydrogen storage is dramatically decreased by more than 4 orders of magnitude from the corresponding pressure in the metastable bulk state. The solid-solution state is still maintained in the nanoparticles even after hydrogen absorption/desorption, in contrast to the metastable bulks which are separated into Pd and Rh during the process. 相似文献
33.
Y. Hatsukawa Y. Miyamoto Y. Toh M. Oshima M. Hosein Mahmudy Gharaie K. Goto K. Toyoda 《Journal of Radioanalytical and Nuclear Chemistry》2007,272(2):273-276
In this study, using neutron activation analysis with multi-parameter coincidence method which was developed at Japan Atomic
Energy Agency (JAEA), a non-destructive, ultra-high sensitive multi-elemental determination has been realized. The multi-parameter
coincidence method is carried out with an array of 19 germanium detectors, GEMINI-II. Using this system, very weak γ-rays
emitted from trace amounts of elements can be detected. The iridium concentration has been determined by means of neutron
activation analysis with multi-parameter coincidence method for Cuban sediment samples across the K/T boundary strata. 相似文献
34.
35.
M. Sugawara Y. Toh T. Czosnyka M. Oshima T. Hayakawa H. Kusakari Y. Hatsukawa J. Katakura N. Shinohara M. Matsuda T. Morikawa A. Seki F. Sakata 《The European Physical Journal A - Hadrons and Nuclei》2003,16(3):409-414
Electromagnetic properties of the low-lying states in a 70Ge nucleus were studied through the multiple Coulomb excitation of a 70Ge beam with a natPb target. Relative γ-ray intensities were measured as a function of emission angle relative to the scattered projectile.
Sixteen E2 matrix elements, including diagonal ones, for 6 low-lying states have been determined using the least-squares search code
GOSIA. The expectation values 〈Q
2〉 of 01
+ and 02
+ states in 70Ge are compared with those in 72, 74, 76Ge. Simple mixing calculations indicate that the 02
+ states in 70Ge and 72Se can be treated as deformed intruder states. It is shown that the deformed intruder becomes the ground state in 74Kr. These interpretations of the 02
+ states in this region are compared with the potential-energy surface calculations by the Nilsson-Strutinsky model, which
allow to interpret the experimental results in a qualitative way from the theoretical point of view.
Received: 2 September 2002 / Accepted: 5 November 2002 / Published online: 25 February 2003
RID="a"
ID="a"e-mail: sugawara@pf.it-chiba.ac.jp
Communicated by D. Schwalm 相似文献
36.
利用在束γ谱学方法,通过反应144Sm(28Si,1p3n)169Re研究了169Re的激发态能级结构.实验进行了X-γ符合、γ-γ符合、DCO系数和带内B(M1)/B(E2)比率测量.基于这些测量,建立了组态为π9/2-[514]的强耦合带和组态为π1/2-[541]的退耦合带.通过比较169Re的转动带与邻近奇质子核已知转动带的结构和B(M1)/B(E2)比率,指定了169Re转动带的组态.实验观测到π9/2-[514]和π1/2-[541]转动带的中子AB带交叉的转动频率分别为0.23和0.27MeV.着重讨论了169Re转动带的中子AB带交叉频率、转动角动量顺排和旋称劈列等,并讨论了奇ARe核转动带结构的系统性 相似文献
37.
For the problem of minimizing the sum of Euclidean norms (MSN), most existing quadratically convergent algorithms require a strict complementarity assumption. However, this assumption is not satisfied for a number of MSN problems. In this paper, we present a globally and quadratically convergent algorithm for the MSN problem. In particular, the quadratic convergence result is obtained without assuming strict complementarity. Examples without strictly complementary solutions are given to show that our algorithm can indeed achieve quadratic convergence. Preliminary numerical results are reported. 相似文献
38.
利用重离子熔合蒸发反应149Sm(27Al,4nγ)172Re布居了形变双奇核172Re的高自旋态,用12套带有BGO反康普顿抑制的高纯锗探测器阵列进行了在束γ实验测量,首次建立了形变双奇核172Re由3个转动带构成的高自旋态能级纲图.研究和讨论了3个转动带的结构特征,基于已有的高自旋态核结构知识并通过系统学比较和分析指出它们的准粒子组态分别为πh11/2⊙νi13/2,πh9/2⊙νi13/2和π1/2-[541]⊙ν1/2-[521].发现前两个转动带在自旋小于18.5h时其转动能级呈现反常的旋称劈裂. 相似文献
39.
We consider the problem of finding solutions of systems of monotone equations. The Newton-type algorithm proposed in Ref. 1 has a very nice global convergence property in that the whole sequence of iterates generated by this algorithm converges to a solution, if it exists. Superlinear convergence of this algorithm is obtained under a standard nonsingularity assumption. The nonsingularity condition implies that the problem has a unique solution; thus, for a problem with more than one solution, such a nonsingularity condition cannot hold. In this paper, we show that the superlinear convergence of this algorithm still holds under a local error-bound assumption that is weaker than the standard nonsingularity condition. The local error-bound condition may hold even for problems with nonunique solutions. As an application, we obtain a Newton algorithm with very nice global and superlinear convergence for the minimum norm solution of linear programs.This research was supported by the Singapore-MIT Alliance and the Australian Research Council. 相似文献
40.
This paper presents an optical method which is based on speckle-shearing interferometry for the measurement of the slope at any point of an object. The object under study is illuminated by an expanded laser beam and its image is recorded on a photographic plate placed at the image plane of an image-shearing camera. A second exposure on the photographic film is made after the light source is moved slightly. The resulting photograph yields a fringe pattern which represents lines of constant displacement gradients. Theory of the method as well as some experimental results are presented. 相似文献