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81.
S.T. Chui 《Solid State Communications》1979,29(6):491-493
Recent experiments on the (100) face of W with and without H is interpreted. The significance of large thermal fluctuation in low dimensionality situation and their observation in the present system is pointed out. A thermal impurity depinning transition is discussed. The existence of a commensurate-incommensurate transition as hydrogen coverage is changed is speculated. 相似文献
82.
Lifetimes of high spin states up to {
}=22+ in the yrast positive parity bands have been measured to investigate the shape evolution with increasing spin in 72, 74Se. The Q
t values derived from these measurements indicate that prolate shape stabilizes for 72Se, while a triaxial shape develops for 74Se at higher spins. Comparison of the observed trend in Q
t with spin for 72, 74Se with that of the corresponding kryptones isotones emphasizes the stability provided by N=38 prolate shell gap even at high rotational frequency. 相似文献
83.
K. Esfarjani S.T. Chui V. Kumar Y. Kamazoe 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2002,21(2):181-189
We investigate the statics and dynamics of spatial phase segregation process of a mixture of fermion atoms in a harmonic trap
using the density functional theory. The kinetic energy of the fermion gas is written in terms of the density and its gradients.
Several cases have been studied by neglecting the gradient terms (the Thomas-Fermi limit) which are then compared with the
Monte-Carlo results using the full gradient corrected kinetic energy. A linear instability analysis has been performed using
the random-phase approximation. Near the onset of instability, the fastest unstable mode for spinodal decomposition is found
to occur at q = 0. However, in the strong coupling limit, many more modes with q ≈ K
F decay with comparable time scales.
Received 12 September 2001 Published online 24 September 2002
RID="a"
ID="a"e-mail: k1@sharif.edu
RID="b"
ID="b"Permanent address: Dr. Vijay Kumar Foundation, 45 Bazaar Street, K.K. Nagar (West), Chennai 600 078, India. 相似文献
84.
The notion of bi-inner product functionals
generated by two Bessel sequences {f
n
} and {g
n
} of functions from L
2
was introduced in our earlier work as a vehicle to identify dual frames and bi-orthogonal Riesz bases of L
2. The objective was to find conditions under which P is a constant mu<iple of the inner product <f,g> of L
2. A necessary and suffici condition derived in is that P is both spatial shift-invariant and phase shift-invariant. A<hough these two shift-invariance properties are, in general, unrelated, it could happen that one is a consequence of the other for certain clases of Bessel sequences {f
n
} and {g
n
}. In this paper, we show that, indeed, for localized cosines with two-overlapping windoes (i.e., only adjacent window functions are allowed to overlap), spatial shift-invariance of P is already sufficient to guarantee that P is a constant mu<iple of the inner product, while phase shift-invariance is not. Hence, phase shift-invariance of P for two-overlapping localized cosine Bessel sequences is a consequence of spatial shift-invariance, but the converse is not valid. As an application, we also show that two families of localized cosines with uniformly bounded and two-overlapping windows are bi-orthogonal Riesz bases of L
2, if and only if P is spatial shift-invariant. In addition, we apply this resu< to generalize a resu< on characterization of dual localized cosine bases in our earlier work in to the mu<ivariate setting. A method for computing the dual windows is also given in this paper. 相似文献
85.
86.
Understanding the Origins of Nucleophilic Hydride Reactivity of a Sodium Hydride–Iodide Composite 下载免费PDF全文
Zonghan Hong Derek Yiren Ong Dr. Subas Kumar Muduli Dr. Pei Chui Too Guo Hao Chan Dr. Ya Lin Tnay Prof. Shunsuke Chiba Dr. Yusuke Nishiyama Prof. Hajime Hirao Prof. Han Sen Soo 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(21):7108-7114
Sodium hydride (NaH) has been commonly used as a Brønsted base in chemical syntheses, while it has rarely been employed to add hydride (H?) to unsaturated electrophiles. We previously developed a procedure to activate NaH through the addition of a soluble iodide source and found that the new NaH–NaI composite can effect even stereoselective nucleophilic hydride reductions of nitriles, imines, and carbonyl compounds. In this work, we report that mixing NaH with NaI or LiI in tetrahydrofuran (THF) as a solvent provides a new inorganic composite, which consists of NaI interspersed with activated NaH, as revealed by powder X‐ray diffraction, and both solid‐state NMR and X‐ray photoelectron spectroscopies. DFT calculations imply that this remarkably simple inorganic composite, which is comprised of NaH and NaI, gains nucleophilic hydridic character similar to covalent hydrides, resulting in unprecedented and unique hydride donor chemical reactivity. 相似文献
87.
Chui‐Peng Kong Zeng‐Xia Zhao Hong‐Xing Zhang 《International journal of quantum chemistry》2013,113(8):1162-1170
Mechanisms for hydroxide radicals reacting with 2,3‐epoxy‐1,4‐butanediol (BEPOX) and 2‐methyl‐2,3‐epoxy‐1,4‐butanediol (β‐IEPOX) in the gas phase are investigated using quantum chemistry computations. Geometries of all the structures are optimized at the X3LYP/6‐31+g(d,p) level. The ground‐state energy for each structure is then refined at the CCSD(T)/6‐31+g(d,p) level. All possible reaction paths for BEPOX and β‐IEPOX are analyzed. The results show that during BEPOX and β‐IEPOX gas phase reactions, hydrogen abstractions on Cchain? H are the most energetically favorable reaction paths (S3, S7) while the addition reactions (S6, S9) are not likely to occur. The present theoretical study is consistent with previous experimental results. © 2013 Wiley Periodicals, Inc. 相似文献
88.
Summary We present a general framework for the construction of local interpolation methods with a given approximation order. Some applications to multivariate spline spaces are presented.Supported by the National Science Foundation, Contract Nos. DMS-8602337 and DMS-8701190Sponsored by Defense Advanced Research Projects Agency (DARPA), under contract No. MDA 972-88-C-0047 for DARPA Initiative in Concurrent Engineering (DICE) 相似文献
89.
In this paper we study the characterization of the solution to the extremal problem inf{‖x‖x ∈C ∩M}, wherex is in a Hilbert spaceH, C is a convex cone, andM is a translate of a subspace ofH determined by interpolation conditions. We introduce a simple geometric property called the “conical hull intersection property” that provides a unifying framework for most of the basic results in the subject of optimal constrained approximation. Our approach naturally lends itself to considering the data cone as opposed to the constraint cone. A nice characterization of the solution occurs, for example, if the data vector associated withM is an interior point of the data cone. 相似文献
90.
Chui Lin RONG Xin Cheng LIAO Jian Chen ZHANG Shu Xia CAO Lun LIU Yu Fen ZHAO 《中国化学快报》2005,16(9):1140-1142
Different hydroxy substituted coumarins were successfully phosphorylated with diisopropylphophite (DIPPH) by the Atherton-Todd reaction in 76-89% yields. Moreover, the reaction activities of different hydroxys of the coumarins in the Atherton-Todd reaction were studied. 相似文献