Ultrasonic Determination of the Jahn–Teller Effect Parameters in Impurity-Containing Crystals

Journal of Experimental and Theoretical Physics - A method is developed to determine the symmetry properties of strains and the type of Jahn–Teller effect in crystals with impurity ions in a...     

QCD PERTURBATION THEORY AND NUCLEI (1) THE ENERGY SHIFTS OF HADRENS AND HADRONS MASS DIFFERENCE MASS DIFFERENCE

QCD perturbation theory for confined quarks and gluons (inhadrons) is discussed.Based on the equivalent potential for the quark-gluon interaction derived, the energyshifts of hadrons and hadron mass difference in MIT bag (cavity) model and correcpond-ing approximation of the w. f. with Gassian form are calculated.     

Highly active sites of NiVB nanoparticles dispersed onto graphene nanosheets towards efficient and pH-universal overall water splitting

Production of hydrogen (H2) and oxygen (O2) through electrocatalytic water splitting is one of the sustainable,green and pivotal ways to accomplish the ever-inc...     

Theoretical Investigations of Nonlinear Optical Properties of Transition Metal Cluster Anions

In the framework of density functional theory （DFT）, the electronic excitations and nonlinear optical （NLO） properties of six binuclear transition metal cluster anions with the formula of [Ch2M-（μ-Ch）2-M＇CN]^2- （M = Mo, W; Ch = S, Se; M＇ = Cu, Ag） have been systemically investigated at both cases of gas phase and DMF solution. The obtained electronic absorption spectra reveal that the element replacements of metals M and ligands Ch have significant influence on the absorptions, especially on the low-lying ones. In addition, the transitions of μ-Ch→M are dominant for the low-lying excitations, whereas the transitions of M＇→M as well as Ch→M are mainly responsible for the higher excitations. The calculated molecular first and second hyperpolarizabilities present the remarkable element substitution and solvent effects. The analyses show that the transitions involving μ-Ch→M charge transfer make the critical contributions to the first hyperpolarizability t, and that the charge transfers from the moieties of MCh4 to M＇CN as well as those of μ-Ch→M and M＇→M are responsible for the second hyperpolarizability y. Moreover, the introduction of solvent leads to the results that the transitions within the moieties of MCh4 and M＇CN make larger contributions to the hyperpolarizability, especially to γ.     

Synthesis and spectral properties of some N-(2-benzimidazoyl)-α-aminoesters and their N-oxides

A series of new N-(2-benzimidazol)(S)-α-aminoesters and the respective N-oxides have been prepared, and their spectral data discussed. The CD spectra of the aliphatic and aromatic amino ester derivatives of either series show sign reversal for the observed Cotton effect (CE) band. This chiroptical behaviour was rationalized as due to differences in conformational isomerism.     

New diterpene isopimara-7,15-dien-19-oic acid and its prolyl endopeptidase inhibitory activity

The ethanolic extract of the bulbs of Fritillaria imperialis was subjected to fractionation by solvent-solvent extraction. The nonpolar fraction showed inhibitory activity against prolyl endopeptidase (PEP) (EC.3.4.21.26), a large intracellular enzyme that preferentially hydrolyze proline-containing oligopeptidase at the carboxylic side of a prolyl residue. We have isolated a diterpenoid isopimara-7,15-dien-19-oic acid (1) from the nonpolar fraction of F. imperialis, and on methylation of compound 1, a methylester 2 was obtained which is a known compound previously isolated from Fritillaria thunbergii. The present article describes the isolation and structural elucidation of isopimara-7,15-dien-19-oic acid (1) by single-crystal X-ray diffraction techniques along with its prolyl endopeptidase inhibitory activity.     

Biotransformation of (+)-androst-4-ene-3,17-dione

Fermentation of (+)-androst-4-ene-3,17-dione (1) with Curvularia lunata for 10 days yielded five oxidative and reductive metabolites, androsta-1,4-diene-3,17-dione (2), 17beta-hydroxyandrosta-1,4-dien-3-one (3), 11alpha-hydroxyandrost-4-ene-3,17-dione (4), 11alpha,17beta-dihydroxyandrost-4-en-3-one (5) and 15alpha-hydroxyandrosta-1,4-dien-17-one (6). The structures of these metabolites were elucidated on the basis of spectroscopic techniques. These microbially transformed products were assayed against the clinically important enzymes, tyrosinase and prolyl endopeptidase.     

Separation and analysis of aluminium(III) by cation exchange ion chromatography

A method for the determination of aluminium(III) ions based on separation by cation exchange column chromatography and detection by conductivity detector has been developed. It is fast and reliable, and can be used for the separation and analysis of aluminium(III) ions from other metal ions like Mg(II), Mn(II), Zn(II), Co(II), Ca(II), Sr(II), rare earth elements like Lu(III), Tm(III), and Gd(III), which are eluted at different times and so do not interfere. Effect of p-phenylene diamine concentration present in the eluent, presence of other metal ions and effect of various anions present in the injection sample on the separation and analysis of aluminium(III) ions have also been studied.     

TDDFT Studies of Electronic Structure and First Hyperpolarizability of Tetra-nuclear Cubane-like Transition Metal Clusters

A series of tri-nuclear transition metal clusters with incomplete cubane-like configurations have been studied by TDDFT method. The calculations show that they have enormously large second-order polarizabilities () and are potential nonlinear optical materials for infrared double frequency conversion1. In this paper some tetra-nuclear transition metal clusters with cubane-like configurations, MCu3X4 (PPh3)3 (M=W, Mo; X= S, O, Cl, Se, Br), were studied by TDDFT method for a reference…     

Examining prospective mathematics teachers' pedagogical content knowledge on fractions in terms of students' mistakes

The aim of the study is to examine prospective mathematics teachers’ pedagogical content knowledge in terms of knowledge of understanding students and knowledge of instructional strategies which are the subcomponents of pedagogical content knowledge. The participants of this research consist of 98 prospective teachers who are studying in two universities in Turkey. The participants were selected with the purposive sampling method which is one of the non-random sampling methods. Case study method, which is based on the qualitative research approach, was used. The answers given by secondary school students to fraction-related open-ended questions in the study of Soylu and Soylu were used as the data collection tool. The obtained data were analyzed via the content analysis technique. The analyses showed that the prospective mathematics teachers’ pedagogical content knowledge on fractions was not at an adequate level in identifying and correcting students’ errors. However, it was observed that the prospective teachers experienced more difficulty in the knowledge of instructional strategies compared to the knowledge of understanding students.