α-quartz型GeO2高压相变的分子动力学研究

采用在经典离子晶体作用势中附加Ｍｏｒｓｅ势,并进行必要的量子化修正,对α－ｑｕａｒｔｚ型ＧｅＯ２结构随压力变化特性,进行分子动力学计算模拟,获得了在压力高于６．０ＧＰａ,α－型ＧｅＯ２从晶相向非晶相相变的模拟结果,并利用其摩尔体积变化,键角、径向分布１、配位数等重要信息对模拟结果作了深入的探讨,相变后的非晶相,由占体积６６％的八面体结构和３３％的四面体结构组成的非晶体,其中还有极少量的α－ｑｕａｒｔｚ型ＧｅＯ２存在。     

Observation of M3 isomeric transition from <Superscript>156m</Superscript>Pm through the βdecay of <Superscript>156</Superscript>Nd

An M3 transition in a doubly odd nucleus of ¹⁵⁶Pm was identified by internal conversion electron measurement through the β-decay of ¹⁵⁶Nd which was separated from the fission products of ²³⁵U using the on-line mass separator KUR-ISOL. The isomeric state at 150.3keV de-excites to the ground state with the M3 transition, and the spin-parity is considered to be 1^-. Nilsson configurations are also discussed on the basis of the systematics.     

X-ray Structure of a 1:2 Complex of Hexakis (3-O-acetyl-2,6-di-O-methyl)-α-cyclodextrin with Butylacetate

Abstract

Crystal structure of a 1:2 complex of hexakis(3-O-acetyl-2,6-di-O-methyl)-α-cyclodextrin (ADMACD) with butylacetate was determined by the X-ray method. The space group of the crystal is P2₁2₁2₁ with Z = 4 and D _x = 1.293 g cm^?3, and the cell dimensions are a = 11.087(2), b = 23.543(3), and c = 31.739(6) Å. The structure was solved by the direct method and refined to the R-value of 0.123 for all the 4993 observed reflections with 1<0. The ADMACD molecule is in a round shape with the pseudo hexagonal symmetry. Methyl and acetyl groups point towards the outside of the molecule. Because of the acetyl groups attached to O3 and methyl groups attached to O6, the intramolecular cavity is ca. 3 Å deeper than the cavity of native α-CD. One butylacetate molecule is coaxially accommodated with its acetyl group at the O6 side in the host cavity while the other guest molecule is located in an intermolecular space between host molecules which are stacked to form a head-to-tail channel-type packing structure along the a axis.     

The design and characteristic features of a new time-of-flight mass spectrometer with a spiral ion trajectory

A new time-of-flight (TOF) mass spectrometer with a corkscrew ion trajectory was designed and constructed. The spiral trajectory was realized by using four toroidal electrostatic sectors. Each had fifteen-stories made of sixteen Matsuda plates piled up inside a cylindrical electrostatic sector. The ions passed the four toroidal electrostatic sectors sequentially and revolved along a figure-eight-shaped orbit on a certain projection plane. During the multiple revolutions, each ion trajectory was shifted by 50 mm per cycle on a direction perpendicular to the projection plane, thus generating a spiral trajectory. The flight path length of one cycle was 1.308 m so that the maximum flight path length became approximately 20 m. The mass resolution, mass accuracy, and ion transmission were tested by utilizing an orthogonally coupled electron ionization source. A mass resolution of 35,000 (FWHM) for m/z greater than 300 was achieved. Even in a lower mass region, mass resolutions of more than 20,000 (FWHM) were confirmed with a doublet of (12)C(5)(1)H(5)(14)N(+) and (13)C(12)C(5)(1)H(6)(+). The mass accuracy was also improved such that it was better than 1 ppm with only one internal standard peak. An ion transmission of approximately of 100% was observed for 15 cycles.     

Reaction and characterization of thioamide dianions derived from N-benzyl thioamides

Thioamide dianions were generated by the highly efficient reaction of N-benzyl thioamides with 2 equiv of BuLi. Alkylation, allylation, and silylation took place selectively at the carbon atom adjacent to the nitrogen atom of the thioamide dianions. Oxiranes and an aldehyde were also used as electrophiles in the reaction of thioamide dianions to form N-thioacyl 1,3- or 1,2-amino alcohols. The insertion reaction of elemental sulfur to a thioamide dianion and subsequent ethylation afforded a N-thioacyl hemithioaminal. NMR studies on the thioamide mono- and dianions derived from N-benzyl 2-methoxythiobenzamide showed a linear relationship between the chemical shifts of all carbon atoms of thioamide mono- and dianions. The results also suggested that the negative charge at the benzylic carbon atom of the dianion is not fully delocalized. The charge distribution patterns of the dianion are consistent with those of pi polarization.     

α-quartz型GeO2高压相变的分子动力学研究

采用在经典离子晶体作用势中附加Morse势,并进行必要的量子化修正,对α-quartz型GeO2结构随压力变化特性,进行分子动力学计算模拟,获得了在压力高于6.0 GPa, α-quartz型GeO2从晶相向非晶相相变的模拟结果,并利用其摩尔体积变化、键角、径向分布、配位数等重要信息对模拟结果作了深入的探讨;相变后的非晶相,由占体积66%的八面体结构和33%的四面体结构组成的非晶体,其中还有极少量的α-quartz型GeO2存在。     

Two-Dimensional Super High Density Multi-Fiber Connector

We have developed 32-fiber and 60-fiber super high density multi fiber connector. This 32-fiber connector can be applicable for single-mode fiber and 60-fiber connector for multi-mode fiber. We have also established PC (physical contact) connection technology by optimizing polishing condition and clamping force.