DFT study and vibrational spectra of the phoshorus-containing G0 generation dendrimer

The Raman (10–3500 cm⁻¹) and infrared (150–3500 cm⁻¹) spectra have been recorded for tris(4-oxibenzaldehyde)thiophosphate. This compound includes structural parts of elementoorganic dendrimers: a core and terminal aldehyde groups. The structural optimization and normal mode analysis are performed for elementoorganic dendrimer on the basis of the ab initio density functional theory. It is found that the dendrimer exist in a single stable conformation with planar C₆H₄CHO fragments. Our calculations show that conformer with one trans and two gauche 4-oxibenzaldehyde groups is realized. All these observations suggest that steric congestion does not disturb the construction of dendrimers even for the highest generations, and that terminal groups are readily available for further reactions. Relying on DFT calculations a complete vibrational assignment is proposed for different parts of the studied dendrimers.     

Probabilistic models for stochastic elliptic partial differential equations

Mathematical requirements that the random coefficients of stochastic elliptical partial differential equations must satisfy such that they have unique solutions have been studied extensively. Yet, additional constraints that these coefficients must satisfy to provide realistic representations for physical quantities, referred to as physical requirements, have not been examined systematically.     

Polychronous kinetics with nonstationary rate constants. Effect of a medium

Characteristic features of the kinetics of solid-state cage reactions with distributed parameters of the relaxing matrix were considered. Depending on the ratio of the constants of the reaction rate and relaxation of environment, the kinetics of chemical conversions can be either exponential or nonexponential. Plausible reasons for the unsteady-state character of the kinetics of the processes of two types,viz., the reactions of alkyl radicals in amorphous alcohol matrices and conversions in biological systems, were discussed. The main reason for the unsteady-state character of the reactions of the first type is a dispersion of the equilibrium distances between the reagents. Kinetics of the reactions of the second type, such as rebinding of the ligands in the heme-containing proteins (e.g., in myoglobin), is determined by the distances in the pairs of reagents and the relaxation transitions. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 469–476, March, 1997.     

参数法和非参数法估计组合样中被测组分含量的置信区间

本文以散装生铁块的随机样本分析结果为基础,应用Ｍｏｎｔｅ Ｃａｒｌｏ模拟法考察了组合样本中Ｓｉ、Ｍｎ,Ｃ,Ｓ,Ｐ含量（或份样平均值）的分布情况,研究了组分含量的置信区间,对参数法和非参数法的结果进行了比较。结果表明,对近似符合正态分布的原始总体或当组合样中的份样数目较多时,两种方法所估计的置信区间相近。但对偏离正态分布（或ｔ－分布）的总体且组合样中的份样数目较少时,非参数法较参数法的结果更符合实际     

Geometric Design of Anode-Supported Micro-Tubular Solid Oxide Fuel Cells by Multiphysics Simulations

High volumetric power density (VPD) is the basis for the commercial success of micro-tubular solid oxide fuel cells (mtSOFCs). To find maximal VPD (MVPD) for anode-supported mtSOFC (as-mtSOFC), the effects of geometric parameters on VPD are analyzed and the anode thickness, t_an, and the cathode length, l_ca, are identified as the key design parameters. Thermo-fluid electrochemical models were built to examine the dependence of the electrical output on the cell parameters. The multiphysics model is validated by reproducing the experimental I-V curves with no adjustable parameters. The optimal l_ca and the corresponding MVPDs are then determined by the multiphysics model for 20 combinations of r_in, the inner tube radius, and t_an. And all these optimization are made at 1073.15 K. The results show that:(i) significant performance improvement may be achieved by geometry optimization, (ii) the seemingly high MVPD of 11 and 14 W/cm³ can be easily realized for as-mtSOFC with single-and double-terminal anode current collection, respectively. Moreover, the variation of the area specific power density with l_ca2(2 mm, 40 mm) is determined for three representative (r_in, t_an) combinations. Besides, it is demonstrated that the current output of mtSOFC with proper geometric parameters is comparable to that of planar SOFC.     

Perturbed structures generated using coordinates derived from compliance constants in internal vibrations for QTAIM dual functional analysis: Intrinsic dynamic nature of interactions

Perturbed structures for QTAIM dual functional analysis (QTAIM‐DFA) are proposed to generate using the coordinates corresponding to the compliance force constants in internal vibrations (CIV). In QTAIM‐DFA, total electron energy densities H_b( r _c) are plotted versus H_b( r _c) – V_b( r _c)/2 at bond critical points (BCPs) of interactions in question, where V_b( r _c) are potential energy densities at BCPs. Each plot of an interaction based on the data from both perturbed structures and fully optimized one takes the form (θ_p, κ_p), where θ_p corresponds to the tangent line of the plot and κ_p is the curvature. The θ_p values evaluated with CIV are equal to those obtained by partial optimizations with the interaction distance in question being fixed suitably, within the calculation errors. Very high applicability of CIV is demonstrated to generate the perturbed structures for QTAIM‐DFA. Dynamic nature of interactions based on (θ_p, κ_p) with CIV is called “intrinsic dynamic nature of interactions.”     

Application of the Spherical Harmonic Model to the ν(CO) Vibrational Spectra of Some Fe(CO)4 and M(CO)5 (M=Cr, W) Transition Metal Cluster Carbonyl Species

When the Fe(CO)₄ and M(CO)₅ (M=Cr, W) groups are co-ordinated in C_3v and C_4v fashion, respectively, in transition metal carbonyl cluster species they contain two sets of non-symmetry related carbonyl groups. In the application of the spherical harmonic model (SHM) to the interpretation of the infrared spectra of these compounds it proves necessary first to treat these as for a normal, isolated, M(CO)₄ or M(CO)₅ group and then apply the SHM. This recognition gives insights into the general application of the SHM.     

Correlation receiver of below-noise pulsed signals based on parametric interactions of spin waves in magnetic films

A correlation receiver capable of receiving pulsed microwave signals having amplitudes substantially below the noise level is proposed and experimentally realized. The device is based on the parametric interaction of two contra-propagating spin waves excited by the received microwave signal and the reference pulsed signal, containing information about the received signal shape, in a ferrite film waveguide. The output nonlinear correlation signal having the doubled carrier frequency and the signal-to-noise ratio enhanced by several orders of magnitude is received by a dielectric resonator coupled to an output microwave transmission line.     

Nonlinear Dynamics of a Three‐Wave CO2 Laser with Loss Modulation

The nonlinear dynamics of a CO₂ laser having continuous electrical discharge pumping and loss modulation and generating in three vibrationalrotational lines of the same vibrational band is investigated theoretically. It is shown that it is possible to monitor the time and energy parameters of radiation in rather wide ranges by changing the depth and frequency of modulation and also the relationship between the constant components of losses. The character of the response of the threewave laser in loss modulation in one or two channels at certain parameters is similar to the response of a system with two degrees of freedom. In loss modulation simultaneously in three channels the response is equivalent to the response of a system with one degree of freedom.     

小波包分解及其参数模型

本文在小波包分析的基础之上，实现了适合于一维信号分析的小波分解算法，并将小波包分析理论和参数模型有机地结合了起来，构造了小波包参数模型。