The β-decay of 47V

The γ-rays emitted following the β-decay of ⁴⁷V have been studied with a 65 cm³ Ge(Li) detector. Direct β-branches were observed to the following levels in ⁴⁷Ti (log ft values in parentheses): ground state (4.9); 1550 keV (6.0); 1794 keV (5.1); 2163 keV (5.3); 2167 keV (6.2); 2526 keV (5.4); 2549 keV (5.7); 2793 keV (5.0). The branches to the last four levels have not been reported previously. In addition, a newγ-decay branch, 2163 → 160 keV, was observed. These results, together with information from reaction studies, permit the assignment of spin and parity $\text{3}\text{2}{}^{\mathrm{?}}$ to the 2163 keV level, and $\text{5}\text{2}{}^{\mathrm{?}}$ to the 2167 keV level. The half-life of the ⁴⁷V decay was measured to be 32.6±0.3 min.     

Thermoacoustic measurements during cure of epoxy resin at room temperature

Dynamic thermoacoustic measurements were used to observe the curing of epoxy resin. Measurements were made at the modulation frequency (20 Hz) as a function of time. A two-step increase of the thermoacoustic signal output was notable and could be explained in terms of the transitions liquid → rubber → glass.     

H2O和N2的谱线碰撞增宽的理论计算

采用Ｔｅｊｗａｎｉ修正的Ａｎｄｅｒｓｏｎ模型和Ａｓｈｏｋ、Ｔｈｏｍｐｓｏｎ计算水的转动能级和波函数的最新程序，计算了水和Ｎ２碰撞谱线增宽，获得了较高量子数的半宽数据     

蒽、菲异构体在用甲基苯基聚硅氧烷改性的氯化镉柱上的色谱性能

用甲基苯基聚硅氧烷改性的氯化镉柱(MPS-CdCl_2)基线分离了蒽、菲异构体。蒽、菲的相对保留值(α_(a/p))和调整保留时间(t’R)随氯化镉含量的提高而增大。MPS-CdCl_2。柱选择性好,柱效稳定。     

Base-promoted ruthenium carbonyl cluster complexes: From fundamental reactions to catalysis

An attempt to establish a link between the rich chemistry of ruthenium carbonyl clusters doped by nucleophilic anions, and the known effect of promoters in some ruthenium-based catalytic processes.     

Nested decomposition of multistage nonlinear programs with recourse

Nested decomposition is extended to the case of arborescent nonlinear programs. Duals of extensive forms of nonlinear multistage stochastic programs constitute a particular class of those problems; the method is tested on a set of problems of that type.     

A new theoretical approach to the encapsulation of small molecules in zeolites

We present a new theoretical method to study the encapsulation of small molecules such as H₂, O₂, N₂, Ar and CH₄ in the Cs₃Na₉-A zeolite. To study the properties of encapsulated molecules, we used the Fermi-Dirac like statistics. The density of states, the distribution function, average binding energy and the average activation energy of encapsulated molecules are calculated. As the number of encapsulated molecules in zeolite cavities increases, the higher energy states in the cavities are gradually filled and, consequently, the activation energy for decapsulation is lowered. We also calculated the fraction of molecules with higher energy than their activation energy, revealing that the activation energy for decapsulation depends not only on the temperature but also on the number of the encapsulated molecules.     

X-ray and neutron diffraction studies of the hydridotriruthenium cluster complex (μ-H)Ru3(CO)7(μ-As(C6H5)CH2As(C6H5)2) ((C6H5 2AsCH2As(C6H5)·CH2Cl2: an example of dibridged metal-metal bond M(μ-H)(μ-X)M,involving a heavy bridgehead atom

The title compound is (μ-H)Ru₃(CO)₇(μ-As(C₆H₅)CH₂As(C₆H₅)₂)((C₆H₅)₂ AsCH₂As(C₆H₅)₂)·CH₂C1₂. Crystal data: monoclinic,P2₁/n, cell parameters (X-ray)a=12.82(2) Å,b=22.91(2) Å,c=17.83(2) Å, β=99.1(3)°; (neutron)a=12.94(1) Å, β=22.95(2)Å,c=17.93(3)Å,β=99.55(5)°. The structure was solved from X-ray data. FinalR indices areR(F)=0.051,R _w (F)=0.049 (X-ray);R(F)=0.064,R _w (F)=0.048,R(F ²)=0.072,R _w (F²)=0.088 (neutron). The complex is derived from Ru₃(CO)₈(dpam)₂ through reaction with hydrogen. The structure consists of a triangular array of metal atoms involving three metal-metal bonds[Ru(1)?Ru(2)=2.912(7)Å;Ru(1)?Ru(3)=2.829(3) A; Ru(2)?Ru(3)=2.845(6) Å]. The metal-metal edge Ru(1)?Ru(2) is supported by a bridging bis(diphenylarsino)methane ligand which lies in the equatorial plane. Activation of the second dpam ligand has generated the new face-bridging ligand unit μ-As(C₆H₅)CH₂As(C₆H₅)₂. In this unit, the bridgehead As atom spans over the Ru(1)?Ru(2) bond, while the second As atom is only bonded to Ru(3). The metal environment is achieved by CO ligands. The hydride ligand is bridging the Ru(1)?Ru(2) vector [Ru(1)?H=1.791(10) Å; Ru(2)?H=1.818(8) Å]. Geometric features of the dibridged Ru(μ-H)(μ-As)Ru bond are discussed.     

New results about normal pairs of rings with zero-divisors

Let $R\subset S$ be a (unital) extension of (commutative) rings. It is proved in Theorem 1, that $(R, S)$ is a normal pair (i.e. $T$ is integrally closed in $S$ for each ring $T$ such that $R \subseteq T \subseteq S$ ) if and only if $R\subset S$ is a $P$ -extension and $R$ is integrally closed in $S$ . Theorem 2 states that for rings $R\subseteq T \subseteq S, R\subseteq S$ is a $P$ -extension if and only if $R\subseteq T$ and $T\subseteq S$ are $P$ -extensions. As a consequence, we prove that if $R\subseteq T \subseteq B$ are rings and if $\overline{R}_T$ (respectively, $\overline{R}_B$ ) is the integral closure of $R$ in $T$ (respectively, in $B$ ), then $(\overline{R}_T, T)$ is a normal pair if and only if $(\overline{R}_B, \overline{R}_BT)$ is a normal pair. This generalizes results of Prüfer and Heinzer on Prüfer domains to normal pairs of arbitrary rings.