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排序方式: 共有490条查询结果,搜索用时 46 毫秒
91.
We derive differential inequalities and difference inequalities for Riesz means of eigenvalues of the Dirichlet Laplacian,
92.
Raleigh W. Parrott II Christopher G. Hamaker Shawn R. Hitchcock 《Journal of heterocyclic chemistry》2008,45(3):873-878
93.
N. E. Sluchanko A. N. Azarevich M. A. Anisimov A. V. Bogach S. Yu. Gavrilkin V. V. Glushkov S. V. Demishev A. A. Maksimov I. I. Tartakovskii E. V. Filatov V. B. Filippov A. B. Lyashchenko 《JETP Letters》2016,103(11):674-679
High-precision measurements of the Hall effect and Raman scattering have been performed for single crystals of ZrB12 superconductor in the wide temperature range of 5–300 K. For ZrB12, the boson peak with ωmax ~ 100 cm–1 has been observed for the first time within the low-frequency range of the Raman spectrum I(ω). The sizes of vibrational clusters with the correlation length ranging from 25 to 35 Å are estimated. The relation between the renormalization of the low-frequency density of vibrational states accompanying the transition to the cage-glass phase (T* ~ 90 K) and the enhancement of superconductivity in ZrB12 is discussed. 相似文献
94.
Tesia V. Chciuk William R. Anderson Jr. Prof. Robert A. Flowers II 《Angewandte Chemie (International ed. in English)》2016,55(20):6033-6036
The relationship between proton‐donor affinity for SmII ions and the reduction of two substrates (anthracene and benzyl chloride) was examined. A combination of spectroscopic, thermochemical, and kinetic studies show that only those proton donors that coordinate or chelate strongly to SmII promote anthracene reduction through a PCET process. These studies demonstrate that the combination of SmII ions and water does not provide a unique reagent system for formal hydrogen atom transfer to substrates. 相似文献
95.
Miroshnichenko E. A. Kon’kova T. S. Pashchenko L. L. Matyushin Yu. N. Inozemtsev Ya. O. Tartakovskii V. A. 《Russian Chemical Bulletin》2016,65(7):1876-1878
Russian Chemical Bulletin - The standard molar enthalpies of combustion for three methyl and dimethyl nitrooxazolidine derivatives in the liquid and crystalline states were determined using a... 相似文献
96.
Pictet–Spengler Synthesis of Quinoline‐Fused Porphyrins and Phenanthroline‐Fused Diporphyrins
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Dr. Ke Gao Norihito Fukui Seok II Jung Prof. Dr. Hideki Yorimitsu Prof. Dr. Dongho Kim Prof. Dr. Atsuhiro Osuka 《Angewandte Chemie (International ed. in English)》2016,55(42):13038-13042
Doubly and quadruply quinoline‐fused porphyrins were effectively synthesized through a reaction sequence consisting of Suzuki–Miyaura coupling of β‐borylated porphyrins with 2‐iodoaniline and subsequent Pictet–Spengler cyclization. These quinoline‐fused porphyrins display red‐shifted absorption bands and higher electron‐accepting abilities. This synthetic protocol also allowed the synthesis of phenanthroline‐fused porphyrin dimers, which bound either a NiII or ZnII cation. The resultant metal complexes displayed further red shifted absorption spectra and molecular twists to effect an almost perpendicular arrangement of the two porphyrins. 相似文献
97.
We present EQCM study for the electrochemical behavior of various 1-methyl-1'-alkylvilogen (C1CnV:n=1, 7-10, 12, 14,16, 18). In some viologens, we discussed the mechanism of CD-induced comproportionation reaction as well as electrodeposition pathway based on the EQCM and the spectroelectrochemical experimental results. 相似文献
98.
Augustine O. Esogbue Warren E. Hearnes II 《Journal of Computational Analysis and Applications》1999,1(2):121-145
The convergence properties for reinforcement learning approaches, such as temporal differences and Q-learning, have been established under moderate assumptions for discrete state and action spaces. In practice, however, many systems have either continuous action spaces or a large number of discrete elements. This paper presents an approximate dynamic programming approach to reinforcement learning for continuous action set-point regulator problems, which learns near-optimal control policies based on scalar performance measures. The continuous-action space (CAS) algorithm uses derivative-free line search methods to obtain the optimal action in the continuous space. The theoretical convergence properties of the algorithm are presented. Several heuristic stopping criteria are investigated and practical application is illustrated by two example problems—the inverted pendulum balancing problem and the power system stabilization problem. 相似文献
99.
In computational intelligence, the term ‘memetic algorithm’ has come to be associated with the algorithmic pairing of a global search method with a local search method. In a sociological context, a ‘meme’ has been loosely defined as a unit of cultural information, the social analog of genes for individuals. Both of these definitions are inadequate, as ‘memetic algorithm’ is too specific, and ultimately a misnomer, as much as a ‘meme’ is defined too generally to be of scientific use. In this paper, we extend the notion of memes from a computational viewpoint and explore the purpose, definitions, design guidelines and architecture for effective memetic computing. Utilizing two conceptual case studies, we illustrate the power of high-order meme-based learning. With applications ranging from cognitive science to machine learning, memetic computing has the potential to provide much-needed stimulation to the field of computational intelligence by providing a framework for higher order learning. 相似文献
100.
Arthur Jaffe Christian D. Jäkel Roberto E. Martinez II 《Communications in Mathematical Physics》2014,329(1):1-28
We explore a framework for complex classical fields, appropriate for describing quantum field theories. Our fields are linear transformations on a Hilbert space, so they are more general than random variables for a probability measure. Our method generalizes Osterwalder and Schrader’s construction of Euclidean fields. We allow complex-valued classical fields in the case of quantum field theories that describe neutral particles. From an analytic point-of-view, the key to using our method is reflection positivity. We investigate conditions on the Fourier representation of the fields to ensure that reflection positivity holds. We also show how reflection positivity is preserved by various spacetime compactifications of ${\mathbb{R}^{d}}$ in different coordinate directions. 相似文献