Disentangling proton connectivity networks in highly overlapped 1H-NMR spectra of polynuclear aromatics using 1D-HOHAHA

One-dimensional ( 1D ) variants of two-dimensional ( 2D ) nmr techniques can frequently provide the required information in a much shorter period of time than the 2D experiment from which they were derived. Application of the 1D homonuclear Hartmann-Hahn (1D-HOHAHA) experiment to establish proton-proton connectivity networks in highly overlapped four-spin systems in the proton nmr spectra of polynuclear aromatics is described. Selective subspectra are contrasted to the data obtained in a COSY experiment on the same molecule, benzo[f][l]benzothieno [2,3 -c]quinoline. Results from the 1D-HOHAHA technique are especially useful when component resonances from several spin systems are heavily overlapped. Relayed 1D-HOHAHA provides the means of exploiting small, long range coupling pathways of polynuclear aromatics.     

Laser Spectroscopy on the MgH A2Π - X2Σ+ Band System

The A²Π - X²Σ⁺ electronic transition of MgH has been studied by the laser excitation spectroscopy. Some new transitions have been observed for the first time. Rotational parameters of the X and A state have been derived and compared with other experimental values.     

A_(od)≠∞,r_(id)≠∞时比例运算电路的分析与计算

分析了两种比例运算电路在开环放大倍数Aod和差模输入电阻rid均为有限值时的闭环特性 ,导出了Avf,rif和rof的表达式     

Fixed points and exponential stability of mild solutions of stochastic partial differential equations with delays

The fixed-point theory is first used to consider the stability for stochastic partial differential equations with delays. Some conditions for the exponential stability in pth mean as well as in sample path of mild solutions are given. These conditions do not require the monotone decreasing behavior of the delays, which is necessary in [T. Caraballo, K. Liu, Exponential stability of mild solutions of stochastic partial differential equations with delays, Stoch. Anal. Appl. 17 (1999) 743-763; Ruhollan Jahanipur, Stability of stochastic delay evolution equations with monotone nonlinearity, Stoch. Anal. Appl. 21 (2003) 161-181]. Even in this special case, our results also improve the results in [T. Caraballo, K. Liu, Exponential stability of mild solutions of stochastic partial differential equations with delays, Stoch. Anal. Appl. 17 (1999) 743-763].     

一个带阻尼项Josephson振动的半经典模型

在双势阱模型的基础上考虑了Josephson流与凝聚体的相互作用而引起的阻尼效应,得出相对粒子数Z(t)的表达式,并用一个简单的碰撞模型得出Josephson振动的振幅和能量及随时间呈指数衰减,以及凝聚体的质量越大,衰减越慢。     

Nonlinear weighted best simultaneous approximation in Banach spaces

The present paper is concerned with the problem of weighted best simultaneous approximations in Banach spaces. The weighted best simultaneous approximations to sequences from S- and BS-suns in the Banach space are characterized in view of the Kolmogorov conditions. Applications are provided for weighted best simultaneous approximations from RS-sets and strict RS-sets. Our results obtained in the present paper extend and improve all earlier known results in this direction.     

Existence of positive periodic solutions for two kinds of neutral functional differential equations

In this work, we deal with a new existence theory for positive periodic solutions for two kinds of neutral functional differential equations by employing the Krasnoselskii fixed-point theorem. Applying our results to various mathematical models we improve some previous results.     

Optimal harvesting for an age-dependent <Emphasis Type="Italic">n</Emphasis>-dimensional food chain model

This paper is concerned with optimal harvesting policy for an age-dependent n-dimensional food chain model. The existence and uniqueness of non-negative solution of the system are proved using the fixed point theorem. By Mazur＇s theorem, the existence of optimal control strategy is demonstrated and optimality conditions derived by means of normal cone.