Barkhausen jumps in the motion of a single ferroelectric domain wall

It is shown that the motion of a domain wall in the improper ferroelectric-ferroelastic gadolinium molybdate Gd₂(MoO₄)₃ demonstrates a self-organized critical behavior under polarization reversal. Barkhausen pulses are measured experimentally during the jumpwise motion of a single plane domain wall in monocrystalline plates with artificial pinning centers of the “field inhomogeneity” type.     

Quantum-Chemical Study of the Mechanism of Hydrocarbon Oxidation with Molecular Oxygen

The minimal kinetic scheme of the mechanism of hydrocarbon oxidation with molecular oxygen was studied by the PM3 semiempirical quantum-chemical method and also by the B3LYP hybrid density functional method using the 3-21G and 6-21G(d) basis sets and the GAUSSIAN 94 software. The energy characteristics and structural parameters of the reactants, products, and transition states of some elementary stages were determined. The simplest hydrocarbons, methane and ethane, were taken as substrates. For same reactions the effect of substituents, including bulky groups (methylbenzene, ethylbenzene, isopropylbenzene), was considered.     

Spectral and luminescent investigations of ammonia cyclometalated Pt(II) complexes

A method of synthesis of ammonia cyclometalated Pt(II) complexes [Pt(NH₃)₂C∧N]ClO₄, where C∧N is 2-phenylpyridinate or 2-phenylbenzothiazole ion, is developed. The electronic absorption and emission properties of the complexes are studied. It is found that the state responsible for intense long-lived luminescence is the excited charge-transfer state of the ³(d-π*) type, the π* orbital being localized at the corresponding cyclometalating ligand. Formation of platinum blue is observed in air-saturated aqueous solutions of ammonia cyclometalated complexes.     

A new proposal for the discretization of the Griffin—Wheeler—Hartree—Fock equations

A polynomial expansion is proposed as a new way to discretize the Griffin-Wheeler-Hartree-Fock equations of the Generator Coordinate Hartree-Fock method. The implementation of the polynomial expansion in the Generator Coordinate Hartree-Fock method discretizes the Griffin-Wheeler-Hartree-Fock equations through a numerical mesh which is not equally spaced. This procedure makes the optimization of Gaussian exponents in the Generator Coordinate Hartree-Fock method more flexible and more efficient. The results obtained with the polynomial expansion for atomic Hartree-Fock energies show this technique is very powerful when employed in the design of compact and high accurate Gaussian basis sets used in ab initio non-relativistic (Hartree-Fock) and relativistic (Dirac-Fock) calculations.     

Thermochemical study of new volatile palladium(II) and copper(II) β-ketohydrazonates for CVD application

Journal of Thermal Analysis and Calorimetry - The volatile palladium(II) and copper(II) {O,N}-coordinated bis-chelate complexes of a new type, Pd(dmht)2 and Cu(dmht)2, where...     

微波促进的N-取代2,3,3a,4,7,7a-六氢异吲哚-1,3-二酮的Beller法合成

A rapid and facile synthesis of N-substituted 2,3,3a,4,7,7a-hexahydroisoindole-l,3-dione derivatives via microwave-promoted Beller three-component domino reaction of α,β,-unsaturated aldehydes, amides and N-substituted maleimides was described.     

Calculations of chemical equilibria in heparin-arginine-H<Subscript>2</Subscript>O-NaCl and MCl<Subscript>2</Subscript>-heparin-arginine-H<Subscript>2</Subscript>O-NaCl systems (M = Ca<Superscript>2+</Superscript>, Mg<Superscript>2+</Superscript>) in a physiological solution

Chemical equilibria in the high-molecular-weight heparin (Na₄hep)-arginine (HArg)-H₂O-NaCl and MCl₂-Na₄hep-HArg-H₂O-NaCl systems of electrolytes (M = Ca²⁺, Mg²⁺) were calculated by the method of mathematical simulation of chemical equilibria from representative planned pH-metric titration experiment at 2.30 ≤ pH ≤ 10.50 in a physiological solution medium in the presence of 0.154 M NaCl as a background electrolyte at 37°C. The initial concentrations of the basic components were n × 10⁻³ M (n ≤ 4).     

甘氨酸衍生化β-环糊精键合硅胶液相色谱固定相的合成与评价

 β-环糊精键合硅胶经对甲苯磺酰化后,与甘氨酸反应得到甘氨酸衍生化β-环糊精键合硅胶固定相(GCDS)。考察了GCDS对位置异构体、丹磺酰化氨基酸异构体、苯丙酸类药物等的分离性能,研究了流动相中甲醇浓度、pH以及柱温对色谱保留行为的影响。     

[5-(芳亚甲基氨基)-1,3,4-噻二唑-2-基]硫乙酰芳胺的合成及 生物活性研究

在K2CO3存在下利用聚乙二醇-400 (PEG-400)作相转移催化剂, 于固-液相转移催化条件下, 通过5-芳亚甲基氨 基-2-巯基-1,3,4-噻二唑与氯乙酰芳胺的硫烷基化反应, 合成了16个未见文献报道的[5-(芳亚甲基氨基)-1,3,4-噻二唑-2-基]硫乙酰芳胺衍生物. 经元素分析, FT-IR,1H NMR和13C NMR确证了其结构. 生物活性实验结果表明, 部分化合物对小麦幼苗的生长具有明显的植物生长调节活性, 并对枯草杆菌具有一定的抑制活性.