Experimental and Theoretical Study of the Electronic States and Spectra of TeH and TeLi

Gas-phase emission spectra of the hitherto unknown free radical TeLi have been measured in the NIR range with a Fourier-transform spectrometer. The emissions were observed from a fast flow system in which tellurium vapor in argon carrier gas was passed through a microwave discharge and mixed with lithium vapor in an observation tube. Two systems of blue-degraded bands were measured at high spectral resolution in the ranges 8000-9000 and 5700-6700 cm(-1) and vibrational and rotational analyses were performed. In order to aid in the analysis of the experimental data, a series of relativistic configuration interaction calculations has been carried out to obtain potential curves for the low-lying states of TeLi and the isovalent TeH and also electric dipole transition moments connecting them. As in the TeH system, the ground state of TeLi is found to be X(2)Pi(i), but with a remarkably smaller spin-orbit splitting. The TeLi calculations indicate a strongly bound A(2)Sigma(+) state, while in TeH the analogous state is computed to lie significantly higher at approximately 32 000 cm(-1), and it is strongly predissociated. Based on the theoretical analysis, the observed TeLi band systems are assigned to the transitions A(2)Sigma(+)(A1/2)-->X(1)(2)Pi(3/2)(X(1)3/2) and A(2)Sigma(+)(A1/2)-->X(2)(2)Pi(1/2)(X(2)1/2). Analysis of the spectra has yielded the molecular constants (in cm(-1)) X(1)(2)Pi(3/2):omega(e)=457.49(3), omega(e)x(e)=2.482(9), B(0)=0.408908(8); X(2)(2)Pi(1/2): T(e)=2353.44(3), omega(e)=456.28(4), omega(e)x(e)=2.635(8), B(0)=0.414954(8), p(0)=1.00637(4); A(2)Sigma(+): T(e)=8574.64(2), omega(e)=437.81(3), omega(e)x(e)=2.581(8), B(0)=0.423903(8), p(0)=-0.19915(2), where the numbers in parentheses are the standard deviations of the parameters. Comparison of the isovalent TeLi and TeH systems emphasizes that the difference in bonding character (ionic in TeLi vs covalent in TeH) is responsible for qualitative differences in the electronic spectra of these two molecules. Copyright 2001 Academic Press.     

Geometry and Elasticity of Strips and Flowers

We solve several problems that involve imposing metrics on surfaces. The problem of a strip with a linear metric gradient is formulated in terms of a Lagrangian similar to those used for spin systems. We are able to show that the low energy state of long strips is a twisted helical state like a telephone cord. We then extend the techniques used in this solution to two–dimensional sheets with more general metrics. We find evolution equations and show that when they are not singular, a surface is determined by knowledge of its metric, and the shape of the surface along one line. Finally, we provide numerical evidence by minimizing a suitable energy functional that once these evolution equations become singular, either the surface is not differentiable, or else the metric deviates from the target metric.     

NOx formation and flame velocity profiles of iso- and n-isomers of butane and butanol

NO formation and flame propagation are studied in premixed flames of iso- and n-isomers of butane and butanol through experimental measurements and direct simulation of experimental profiles. The stabilized flame is realized through the impingement of a premixed combustible jet from a contraction nozzle against a temperature-controlled plate. The velocity field is obtained by means of Particle Image Velocimetry (PIV) and nitric oxide concentration profiles are measured using Planar Laser Induced Fluorescence (PLIF), calibrated using known NO seeding levels. It is found that NO formation in n- and iso-isomers is comparable under the conditions considered, except for rich butanol mixtures, whereby NO formation is higher for iso-butanol. Generally, less NO is formed in butanol flames than in the butane flames. The experiment is simulated by a 1D chemically reacting stagnation flow model, using literature models of C1–C4 hydrocarbons [Wang et al., 2010] and butanol combustion chemistry [Sarathy et al., 2009, 2012]. NO prediction is tested using two of these mechanisms with a previously-published NO_x submechanism added into the butane and butanol models. While a good level of agreement is observed in the velocity field prediction under lean and stoichiometric conditions, discrepancies exist under rich conditions. Greater discrepancies are observed in NO prediction, except for the C1–C4 mechanism which shows good agreement with the experiment under lean and stoichiometric conditions. The current study provides data for further development of mechanisms with NO_x prediction capabilities for the fuels considered here.     

Quantum and surface properties of free films and nanoshells of molecular and atomic thicknesses

An original technology and the properties of new thin film nanoobjects, free films and shells of molecular and atomic thicknesses, are presented. Special attention is paid to shells of monoatomic or monomoleculer thickness with unique surface properties that have not been found in bulk materials.     

Synthesis and characterizations of hollow spheres and nanospheres of Au

Hollow spheres and nanospheres of Au have been prepared by a simple reaction of HAuCl₄·4H₂O, NaOH and (NH₂OH)₂·H₂SO₄ in the presence of gelatin. The role of gelatin and the effect of the temperature of the reaction in producing the spherical particles of Au are discussed. The products were characterized by powder X-ray diffraction (XRD), transmission electron microscopy and UV–Vis absorption spectroscopy. The sizes of the nanospheres of Au were estimated by the Debye–Scherrer formula according to the XRD spectrum. PACS  81.05.Bx; 81.05.Rm; 81.07.-b; 81.16.Be; 81.20.Fw     

Some problems of analysis and optimization of plates and shells

The classical optimization problems of plates and shells to satisfy a priori given geometry and dynamical characteristics are considered. Orthotropic plates and shells with variable thickness and low transverse stiffness are analyzed. First, some useful theorems and their proofs are given. Then the finite approximation of the problem related to optimization of free vibrations of shells with transverse deformation and rotary inertia is discussed. The varational iteration (MVI) and Bubnov-Galerkin (MB) methods are applied, and their convergence and suitability for application to plates and shells analysis are discussed and numerically evaluated.     

MCNP-FISPACT耦合燃耗计算程序开发与测试

反应堆堆芯的燃耗计算关系到堆芯的燃料管理,并直接影响堆芯的经济性评估,因此如何快速且准确地对堆芯进行燃耗计算一直是反应堆物理设计的研究重点之一。随着反应堆的发展,其几何结构和物理特性日渐复杂,现有的一维、二维耦合燃耗程序因其在几何处理上的限制,难以满足先进反应堆精细设计分析的要求。为对复杂反应堆堆芯的燃耗情况进行计算,结合粒子输运程序MCNP 处理复杂几何和燃耗程序FISPACT处理核素全面的特点,开发了接口程序耦合MCNP 和FISPACT来进行燃耗计算,并对耦合程序进行了计算验证。采用了IAEA 基准校核例题和CFETR中国聚变工程实验堆例题进行程序验证,经计算得出的有效倍增因子随燃耗的变化曲线和TBR等数据与标准例题的结果符合良好,其误差在可接受范围内。     

Topological dislocation-type defects and mechanisms of plasticity and failure of nanostructured and amorphous materials

Possible mechanisms of plastic deformation and failure of nanostructured and cluster amorphous materials have been considered. It is shown that the most probable carriers of plastic deformation in these materials are macrodislocations—linear topological defects of the regular nanocrystallite packing in the nanostructure or cluster packing in amorphous materials. Continuum models are proposed to describe the processes of plastic deformation and failure of nanostructured and cluster amorphous materials. Original Russian Text ? L.S. Vasil’ev, S.F. Lomaeva, 2009, published in Izvestiya Rossiiskoi Akademii Nauk. Seriya Fizicheskaya, 2009, Vol. 73, No. 1, pp. 128–131.     

Polarity of the Medium and Quenching of Fluorescence of Caratenoids and Phthalimides

The relation for the dependence of the rate of radiationless energy conversion of the S ₁ state k _q on the polarity of the medium, obtained previously by the author, has been used to interpret the known literature data on the lifetime of the S ₁ state of solutions of some caratenoids and phthalimides. It has been shown that in alcohols and water (normal and deuterated ones) the fluorescence quenching of 4-amino-, 4-methylamino-, and 4-dimethylamino-N-methylphthalimides (4AMP, 4MAMP, and 4DMAMP) as well as of peridinine in alcohols is due to H-bond formation. It has been established that a twofold increase in the number of amine atoms of hydrogen on passing from 4MAMP to 4AMP, as well as deuteration of solvents in the case of 4DMAMP, is followed by a decrease in k _q by a factor of 1.6 and 1.75, respectively. The mechanism of quenching in complexes formed with solvent molecules by means of the H-bond is discussed. It has been concluded that the quenching of fluorescence of phthalimides in such complexes is mainly due to the intersystem crossing initiated by the oscillations of the protons or deuterons of the H-bonds.     

Accuracy and repeatability of QRAPMASTER and MRF-vFA

Our purpose is to evaluate bias and repeatability of the quantitative MRI sequences QRAPMASTER, based on steady-state imaging, and variable Flip Angle MRF (MRF-VFA), based on the transient response.Both techniques are assessed with a standardized phantom and five volunteers on 1.5 T and 3 T clinical scanners. All scans were repeated eight times in consecutive weeks.In the phantom, the mean bias±95% confidence interval for T1 values with QRAPMASTER was 10 ± 10% on 1.5 T and 4 ± 13% on 3.0 T. The mean bias for T1 values with MRF-vFA was 21 ± 17% on 1.5 T and 9 ± 9% on 3.0 T. For T2 values the mean bias with QRAPMASTER was 12 ± 3% on 1.5 T and 23 ± 1% on 3.0 T. For T2 values the mean bias with MRF-vFA was 17 ± 1% on 1.5 T and 19 ± 2% on 3.0 T. QRAPMASTER estimated lower T1 and T2 values than MRF-vFA. Repeatability was good with low coefficients of variation (CoV). Mean CoV ± 95% confidence interval for T1 were 3.2 ± 0.4% on 1.5 T and 4.5 ± 0.8% on 3.0 T with QRAPMASTER and 2.7% ± 0.2% on 1.5 T and 2.5 ± 0.2% on 3.0 T with MRF-vFA. For T2 were 3.3 ± 1.9% on 1.5 T and 3.2 ± 0.6% on 3.0 T with QRAPMASTER and 2.0 ± 0.4% on 1.5 T and 5.7 ± 1.0% on 3.0 T with MRF-vFA.The in-vivo T1 and T2 are in the range of values previously reported by other authors.The in-vivo mean CoV ± 95% confidence interval in gray matter were for T1 1.7 ± 0.2% using QRAPMASTER and 0.7 ± 0.5% using MRF-vFA and for T2 were 0.9 ± 0.4% using QRAPMASTER and 2.4 ± 0.5% using MRF-vFA. In white matter were for T1 0.9 ± 0.3% using QRAPMASTER and 1.3 ± 1.1% using MRF-vFA and for T2 were 0.7 ± 0.4% using QRAPMASTER and 2.4 ± 0.4% using MRF-vFA. A GLM analysis showed that the variations in T1 and T2 mainly depend on the field strength and the subject, but not on the follow-up repetition in different days. This confirms the high repeatability of QRAPMASTER and MRF-vFA.In summary, QRAPMASTER and MRF-vFA on both systems were highly repeatable with moderate accuracy, providing results comparable to standard references. While repeatability was similar for both methods, QRAPMASTER was more accurate. QRAPMASTER is a tested commercial product but MRF-vFA is 4.77 times faster, which would ease the inclusion of quantitative relaxometry.     

Absorption and luminescence of amino- and benzoylaminoanthraquinones

Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 53, No. 3, pp. 396–402, September, 1990.     

受控核聚变两大途径的对比与结合

目前人们探索受控核聚变主要是从两个方向着手：磁约束受控核聚变和惯性约束受控核聚变，但目前还无法判定到底哪一种途径更为可取，文章首先对这两种途径进行对比，指出各自的特点和困难，在此基础上提出了一种结构相对简单，成本相对较低的三轴六极磁镜系统设想，希望能将磁约束和惯性约束和惯性约束结合起来，以实现受控核聚变反应。     

单链核糖体失活蛋白的Raman和红外光谱

我们测定了两种单链核糖体失活蛋白(肥皂草素和天花粉蛋白)的FTIR和FTRaman光谱。利用FTIR光谱酰胺Ⅲ区域对蛋白质的二级结构进行定量分析,计算了各种二级结构的含量。从肥皂草素和天花粉蛋白的二级结构分析可见,二者在结构上具有某种相似性,为二者功能上的相似性提供了依据。     

ORSAT and modifications of SEFT and APT

Up to now, three subspectra are usually needed for the complete assignment of all signals in 13C spectrum: two DEPT spectra (phi = 90 degrees and phi = 135 degrees) and a proton decoupled spectrum. In this paper, we present a method in which a complete assignment becomes possible with merely two spectra. For this purpose, a new pulse sequence (ORSAT) has been elaborated by using off-resonance irradiation. The method described here is a further development of SEFT and APT. The second required spectrum is a DEPT (phi = 135 degrees). Signal assignment of cholesteryl acetate is demonstrated as an example. 13C routine spectroscopy can be significantly accelerated by applying this method.     

Some aspects of nucleation and evolution of microscopic and mesoscopic cracks and quasi-brittle fracture of homogeneous materials

The dynamics of nucleation of microcracks in the region of a developing macroscopic crack has been studied using scanning electron microscopy during in situ experiment and the acoustic emission method. An explosive-like nucleation of microcracks and the influence of dissipative properties of a material on the size and the rate of redistribution of local stresses of the microcracks have been established. Each of nucleations of microscopic and mesoscopic defects is considered as an act of local testing of the dissipative ability of the system, and the interaction between microcracks is determined by relaxation processes when the ability is sufficient. With deteriorating dissipative properties (with increasing residence time under loading, deformation rate, etc.), an elastic linear interaction becomes possible, and the macroscopic fracture occurs. In the microcrack dynamics, a specific ductile-brittle transition is determined by a time deterioration of the dissipative properties of the material under the action of a mechanical load. Generally, as a large latent energy is stored during deformation, a macroscopic fracture can be caused by any little discrete structural transformation.     

Equation of state and thermal expansivity of LiF and NaF

The high-pressure and high-temperature behaviors of LiF and NaF have been studied up to 37 GPa and 1000 K. No phase transformations have been observed for LiF up to the maximum pressure reached. The B1 to B2 transition of NaF at room temperature was observed at ～28 GPa, this transition pressure decreases with temperature. Unit-cell volumes of LiF and NaF B1 phase measured at various pressures and temperatures were fitted using a P–V–T Birch–Murnaghan equation of state. For LiF, the determined parameters are: α₀ = 1.05 (3)×10^?4 K^?1, dK/dT = ?0.025 (2) GPa/K, V ₀ = 65.7 (1) Å³, K ₀ = 73 (2) GPa, and K′ = 3.9 (2). For NaF, α₀ = 1.34 (4)×10^?4 K^?1, dK/dT = ?0.020 (1) GPa/K, V ₀ = 100.2 (2) Å³, K ₀ = 46 (1) GPa, and K′ = 4.5 (1).     

酸碱染料离子的缔合及等色化

本文阐述了等色染料离子对形成的实验方法,等色染料离子对的缔全机理及其形式,用吸收光谱的能级图,从电子理论角度论述了等色染料离子对的缔合效应等色化,溶剂效应等以化机理。列表示出等色染料离子对的高灵敏度,从而证明了等色染料离子对的萃取光度,浮选光度及萃取荧光光度法是高灵敏度和超灵敏度的新体系,为金属痕量和超痕量分析开辟了更为宽广的前景。