HIRFL注入器PIG离子源的研制

本文介绍了兰州重离子加速器(HIRFL)的注入器(SFC)所用PIG离子源的研制和改进工作,使用新研制的PIG源,已在注人器SFC上获得了5μA的O_(16)~(5+)及10μA的C_(16)~(4+)的离子束。     

A high-current electron beam ion trap as an on-line charge breeder for the high precision mass measurement TITAN experiment

The precision of atomic mass measurements in a Penning trap is directly proportional to the charge state q of the ion and, hence, can be increased by using highly charged ions (HCI). For this reason, charge breeding with an electron beam ion trap (EBIT) is employed at TRIUMF’s Ion Trap for Atomic and Nuclear science (TITAN) on-line facility in Vancouver, Canada. By bombarding the injected and trapped singly charged ions with an intense beam of electrons, the charge state of the ions is rapidly increased inside the EBIT. To be compatible with the on-line requirements of short-lived isotopes, very high electron beam current densities are needed. The TITAN EBIT includes a 6 Tesla superconducting magnet and is designed to have electron beam currents and energies of up to 5 A and 60 keV, respectively. Once operational at full capacity, most species can be bred into a He-like configuration within tens of ms. Subsequently, the HCI are extracted, pass a Wien filter to reduce isobaric contamination, are cooled, and injected into a precision Penning trap for mass measurement. We will present the first results and current status of the TITAN EBIT, which has recently been moved to TRIUMF after assembly and commissioning at the Max-Planck-Institute (MPI) for Nuclear Physics in Heidelberg, Germany.     

Hadron production near threshold

Final state interaction effects inpp→ pΛK ⁺ andpd →³Heη reactions are explored near threshold to study the sensitivity of the cross-sections to thepΛ potential and theηN scattering matrix. The final state scattering wave functions between Λ andp andη and³He are described rigorously. The Λ production is described by the exchange of one pion and aK-meson between two protons in the incident channel. Theη production is described by a two-step model, where in the first step a pion is produced. This pion then produces anη by interacting with another nucleon     

Out of Equilibrium Correlations in the XY Chain

We study the transversal spin–spin correlations in the non-equilibrium steady state of the XY chain constructed by coupling a finite cutout of the chain to the two infinite parts to its left and right acting as thermal reservoirs at different temperatures. We prove that the spatial decay of these correlations is at least exponentially fast.     

Regiochemistry of the addition of mercury salts to bornylene

The dependence of the regiochemistry of the mercuration of bornylene on the nature of the mercurating reagent and on the solvent has been found. The structures of the intermediate and transition state in these reactions have been proposed.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 501–505, March, 1994.     

The dehydration of copper(II) acetate monohydrate

The thermal dehydration of copper(II) acetate hydrate has been studied between 353 and 406 K, over a range of humidities. The dehydration is controlled by nucleation-and-growth kinetics at low temperatures, with an activation energy of 154 kJ·mol⁻¹, which changes to contracting-disc kinetics at higher temperatures with a lower activation energy of 76 kJ·mol⁻¹. Frequency factors have also been derived; the value for the high temperature process is low (10⁷s⁻¹) and that for the low temperature step is high (10¹⁷s⁻¹). Optical microscopy has been used to clarify the bulk kinetics; there is evidence for a reactive layer at the surface of the decomposing solid. In celebration of the 60^th birthday of Dr Andrew K. Galwey     

教学研究:介绍量子力学几个基本概念——兼答《关于量子几何相位的评注》中的几个主要问题

介绍了量子绝热定理的物理含义及成立的条件，认为有关主要献（Aharonov-Anandan,Bohm，孙昌璞等）的表述是正确的，而《关于量子几何相位的评注》^[1]（以下简称《评注》）相应的表述不完全正确。在此基础上，认为这些献和教材（R.Shankar)得出的涉及Berry绝热相位的一些论述（不含Berry绝热相因子的瞬时能量本征态不满足含时Schroedinger方程等）也是正确的，而《评注》的论述与此相反。《评注》认为只有γn(C)才是Berry相位。本作则倾向于把γn（t）叫做Berry绝热相位，而把γn（C）=γn（T）-γn（0）叫做几何相位（geometric phase)^[2]。     

Second row transition metal mixed hydride-halide triatomic molecules

Summary The ground state structures and bond energies have been obtained for the triatomic MHX systems where M is the entire sequence of second row transition metal atoms and X is a halide. The most interesting results of this study appear when these systems are compared to the triatomic MH₂ and MX₂ systems. It turns out that the structure of the MHX systems are quite similar to the corresponding MH₂ systems in general. Most of the MHX systems to the right thus have bent low-spin ground states, indicating large covalent contributions to the bonding. RuHX is a special case and has a high-spin linear ground state. For the systems to the left ionicity dominates the bonding. An important result, with implications for halide ligand effects on carbonyl and olefin insertion into M-H and M-R bonds, is that the M-H bonds for the systems to the right have a different character and are significantly weaker for the MHX than for the MH₂ systems. A similar effect is noted when the M-Cl bond strengths of MCl₂ are compared to the ones in MHCl. Both these effects can be explained by a more cationic metal with mores ⁰-state character when halide ligands are present.     

126Cs的高自旋态能级结构

利用融合蒸发反应¹¹⁶Cd(¹⁴N,4n)¹²⁶Cs布居了¹²⁶Cs的高自旋态.观测到了100多条新的γ跃迁和相应的能级,建立了双奇核¹²⁶Cs由9个转动带构成的能级纲图.尝试性地指定了大部分能级的自旋和宇称以及各转动带的Nilsson单粒子组态.极大地丰富了已有的实验结果.     

On interrelation between the internal pressure and the cohesion energy density

The question about the definition of the “internal pressure” concept is being discussed. It is shown that the previously found differential relation between the cohesion energy density and the internal pressure is one of the examples of an absolutely general interrelation between definitely connected differential functions. It is ascertained that the ratio (the internal pressure divided by the cohesion energy density) is a structuresensitive parameter inherent to the calorific (thermal) equation of a liquid state.