Energy spectrum of holes in Sb<Subscript>2</Subscript>Te<Subscript>2.9</Subscript>Se<Subscript>0.1</Subscript> solid solution according to the data on the transfer phenomena

The temperature dependence of the Hall coefficient of a single crystal of the p-Sb₂Te_2.9Se_0.1 solid solution grown by the Czochralski technique is studied in the temperature range 77–450 K. The data on the Hall coefficient of the p-Sb₂Te_2.9Se_0.1 are analyzed in combination with the data on the Seebeck and Nernst–Ettingshausen effects and the electrical conductivity with allowance for interband scattering. From an analysis of the temperature dependences of the four kinetic coefficients, it follows that, at T < 200 K, the experimental data are qualitatively and quantitatively described in terms of the one-band model. At higher temperatures, a complex structure of the valence band and the participation of the second-kind additional carriers (heavy holes) in the kinetic phenomena should be taken into account. It is shown that the calculations of the temperature dependences of the Seebeck and Hall coefficients performed in the two-band model agree with the experimental data with inclusion of the interband scattering when using the following parameters: effective masses of the density of states of light holes m_d1^*≈ 0.5m₀ (m₀ is the free electron mass) and heavy holes m_d2^*≈ 1.4m₀, the energy gap between the main and the additional extremes of the valence band ΔE_v ≈ 0.14 eV that is weakly dependent on temperature.     

Temperature dynamics of triglycine sulfate domain structure according to atomic force microscopy and dielectric spectroscopy data

A hydrogen-containing ferroelectric triglycine sulfate (TGS) was comprehensively studied with an atomic force microscopy (AFM) and dielectric spectroscopy. The domain structure dynamics was in situ investigated with piezoresponse force microscopy (PFM) during heating and cooling the TGS crystal near phase transition. Relaxation dependencies of domain boundaries general perimeter and domain dimensions were obtained. TGS dielectric spectra measured at the frequency range from 10 to 10¹¹ Hz were analyzed on basis of significant contribution of conductivity into the dielectric response of ferroelectrics and a good agreement with the experimental data was received. It allows us to obtain more information about temperature dynamics of the domain structure.     

辐射成像系统模拟软件NUCRPD的研发与应用

在辐射成像系统的设计研发中,经常需要计算系统的各项物理性能指标。为了提升产品研发的效率,同方威视联合清华大学,基于蒙特卡罗程序包Geant4,研发了国内首套具有自主知识产权的辐射成像系统模拟软件NucRPD(NUCTECH Radiography Performance Design Tools),其能够快速、精确地模拟系统的各项性能指标。该软件对常用的一些辐射成像系统进行了参数化建模,用户通过修改软件界面上的少量参数,就可以快速建立各类辐射成像系统的几何体、源项、物理模型和统计量,然后在服务器上以并行计算方式完成模拟计算,能在较短的时间内模拟出系统的性能指标,并给出直观的图形帮助用户深入理解模拟结果。NucRPD的模拟结果经过了大量的实验验证,其剂量场分布和物理指标等模拟结果和实验结果符合得很好。NucRPD已经应用于同方威视辐射成像系统产品的设计研发,在产品的物理指标优化和辐射防护优化中发挥了重要作用。     

Equivalence of Conservation Laws and Equivalence of Potential Systems

We study conservation laws and potential symmetries of (systems of) differential equations applying equivalence relations generated by point transformations between the equations. A Fokker–Planck equation and the Burgers equation are considered as examples. Using reducibility of them to the one-dimensional linear heat equation, we construct complete hierarchies of local and potential conservation laws for them and describe, in some sense, all their potential symmetries. Known results on the subject are interpreted in the proposed framework. This paper is an extended comment on the paper of Mei and Zhang [Int. J. Theor. Phys. 45: 2095–2102, 2006].     

Ternary fission within statistical approach

The ternary system with a light nucleus between two heavy fragments is assumed to appear from the binary configuration near scission. The formation of a third light nucleus in the binary system is considered. The calculated charge distributions in spontaneous ternary fission of ²⁵²Cf and in induced ternary fission of ⁵⁶Ni are compared with the available experimental data. The neutron multiplicity from the fission fragments is described. The fine structures of the TKE-mass distribution are predicted.     

Invariants and radiation of some nonstationary systems

In this paper formulas are obtained by means of the coherent-state method for calculating the radiation power of a nonstationary quantum system ofN charged particles whose Hamiltonian is a general quadratic form with respect to coordinates and momenta. The transitions between the coherent states and the Fock states of this system are discussed. The radiation is calculated both in the dipole approximation and strictly. As an example, the radiation of a charge in homogeneous varying electric and magnetic fields is found. The classical limit is considered.     

XPS study of the electronic structure of heterometallic complexes Fe2MO(Piv)6(HPiv)3 (M = Ni, Co)

Heterometallic complexes Fe₂MO(Piv)₆(HPiv)₃ (M = Ni, Co) have been studied by XPS. The complexes are identified as high-spin complexes with metal atoms in oxidation states M(II) and M(III). A change in the ligand environment of metal atoms has an effect on both the energetic state of metal atoms and the XPS pattern. The substitution of a Co atom for the nickel atom in the heterometallic complexes changes the XPS pattern of iron and their magnetic state. For the Fe₂MO(Piv)₆(HPiv)₃ complexes, quantum-chemical calculations have been performed at the density functional theory (DFT) level. In combination with XPS and magnetochemistry data, the quantum-chemical calculation demonstrates that the Fe, Ni, and Co atoms in the trinuclear complexes are in the high-spin local state and that the ground state is dominated by antiferromagnetic exchange interaction.     

Heptachlorepoxides: theoretical versus experimental study of the embedded samples in the matrixes of organic crystals

The analysis of heptachlorepoxides in gas- and condense phase of embedded in the organic matrixes analyte samples is highlighted. The electrospray ionization, matrix-assisted laser desorption/ionization (MALDI) mass spectrometry (MS), nuclear magnetic resonance, Raman and CD spectroscopy as well as quantum chemical methods are used. The competitive formation of the variety of epoxides, strongly depending of the reaction conditions. Thus, the products of interaction of matrix-analyte matrixes under the UV–MALDI–MS experiment are comprehensively examinated. Nonetheless, that for heptachlor (HA) is known an epoxide, existing in two isomeric forms, i.e. A and B (exo- and endo-one), the study on the mechanism of the epoxidation of HA, showed formation of new epoxides C–F and an intermediate (I), characterizing with high stability, decreasing in the raw F > A > C > B > I > D > E. The epoxide D appeared enantiomer of the insecticide oxychlodran. The reported results on the pesticides, their metabolites and decomposition reactivity products contributed significantly to the field of analytical chemistry, providing possibility for elaboration of highly selective protocols for assessment of environmental contaminant issues.