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The near-edge electronic and structural properties of 2H-NbS(2) were investigated using scanning tunneling microscopy (STM) and density-functional calculations. Geometry optimization of the near-edge structure using density-functional calculations was performed on [1010]- and [1010]-terminated layer edges. Ribbon model systems also included variation of the number of bound sulfur atoms at the edges. Atomic resolution STM data exhibit a pronounced electronic density of states at the outermost edge atomic sites but are otherwise bulk-like in the near-edge region. Optimized NbS2 ribbon structures confirm the STM results indicating that minimal reconstruction occurs and that the edge electronic structure exhibits a significant increase in local density of states compared to bulk. Simulated STM images using extended Hückel tight-binding calculations based on optimized ribbon structures successfully modeled the experimental STM results. The results indicate that the [1010] "Nb" edges are preferentially observed compared to the [1010] "S" edge possibly due to differences in stability. 相似文献
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本文研究了俘获于掺杂VO++离子的(NH4)2Zn(SO4)2·6H2O单晶中NH3+自由基离子的ESR.从实验上分别测出π电子自由基NH3+的14N和15N核超精细分裂.结果表明,氮核超精细偶合张量具有近似于圆柱形对称。对于15N来说,A11=44.8,A22=19.3,A33=17.8高斯.对于14N来说,A11=31.1,A22=12.5,A33=11.8高斯.在室温下,NH3+自由基绕A11方向作圆锥体运动.文中最后讨论了NH3+自由基离子的可能生成机理。 相似文献
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Auslender, Cominetti and Haddou have studied, in the convex case, a new family of penalty/barrier functions. In this paper, we analyze the asymptotic behavior of augmented penalty algorithms using those penalty functions under the usual second order sufficient optimality conditions, and present order of convergence results (superlinear convergence with order of convergence 4/3). Those results are related to the analysis of pure penalty algorithms, as well as augmented penalty using a quadratic penalty function. Limited numerical examples are presented to appreciate the practical impact of this local asymptotic analysis.This research was partially supported by NSERC grant OGP0005491 相似文献
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We introduce the set of bicomplex numbers
which is a commutative ring with zero divisors defined by
where
We present the conjugates and the moduli associated with the bicomplex numbers. Then we study the bicomplex Schr?dinger equation
and found the continuity equations. The discrete symmetries of the system of equations describing the bicomplex Schr?dinger
equation are obtained. Finally, we study the bicomplex Born formulas under the discrete symmetries. We obtain the standard
Born’s formula for the class of bicomplex wave functions having a null hyperbolic angle. 相似文献
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Background
Alpha-Synuclein (α-syn), a 140 amino acid protein associated with presynaptic membranes in brain, is a major constituent of Lewy bodies in Parkinson's disease (PD). Three missense mutations (A30P, A53T and E46K) in the α-syn gene are associated with rare autosomal dominant forms of familial PD. However, the regulation of α-syn's cellular localization in neurons and the effects of the PD-linked mutations are poorly understood.Results
In the present study, we analysed the ability of cytosolic factors to regulate α-syn binding to synaptic membranes. We show that co-incubation with brain cytosol significantly increases the membrane binding of normal and PD-linked mutant α-syn. To characterize cytosolic factor(s) that modulate α-syn binding properties, we investigated the ability of proteins, lipids, ATP and calcium to modulate α-syn membrane interactions. We report that lipids and ATP are two of the principal cytosolic components that modulate Wt and A53T α-syn binding to the synaptic membrane. We further show that 1-O-hexadecyl-2-acetyl-sn-glycero-3-phosphocholine (C16:0 PAF) is one of the principal lipids found in complex with cytosolic proteins and is required to enhance α-syn interaction with synaptic membrane. In addition, the impaired membrane binding observed for A30P α-syn was significantly mitigated by the presence of protease-sensitive factors in brain cytosol.Conclusion
These findings suggest that endogenous brain cytosolic factors regulate Wt and mutant α-syn membrane binding, and could represent potential targets to influence α-syn solubility in brain. 相似文献30.
使用含时密度泛函理论(TDDFT)B3LYP方法计算了IB, IIB, VIIIB过渡金属与8-羟基喹啉络合(MQ)后, 配合物的电子光谱以及二阶非线性光学性质. 结果表明, 掺杂过渡金属后, 形成络合物的能隙值减小100~150 kJ/mol, 最大吸收波长红移150~200 nm左右. 电子从基态到激发态的跃迁主要为p→p*, n→p*跃迁, 属于LLCT, MLCT过程. IB的络合物MQ以及VIIIB的络合物MQ3表现出良好的非线性光学性质. 相似文献