基于现场可编程门阵列的束流快引出控制系统设计

为实现兰州重离子冷却储存环主环束流的快引出,采用一种基于现场可编程门阵列(FPGA)的引出控制系统。在FPGA单元设计中,采用数字倍频技术来实现对Kicker磁铁在1个高频周期内充放电时间的精度控制。经测试,该控制系统对存储环中运行束流位置的跟踪可调节时间步长为5 ns。当高频频率为1.4 MHz时,在0~360°范围内可实现约2.5°相位精度的Kicker触发。

Properties of the pi h(9/2)circle times nu i(13/2) oblate band in Tl-188

High spin states in Tl-188 have been investigated via the Gd-157(Cl-35,4n) reaction at beam energy of 170 MeV. A rotational band built on the pi h(9/2) circle times nu(13/2) configuration with oblate deformation has been established. Considering the similarity between the band structure observed in odd-odd Tl nuclei, spin values have been tentatively proposed for the new band in Tl-188. The pi h(9/2) circle times nu(13/2) oblate band in Tl-188 shows low-spin signature inversion, and it can be interpreted qualitatively by the two quasiparticle plus rotor model including a J-dependent p-n residual interaction.

CONSISTENT THREE-BODY FORCE WITH BONN B POTENTIAL AND NEUTRON STAR STRUCTURE

Microscopic three-nucleon force consistent with the Bonn B two-nucleon potential is constructed, which includes Delta(1232), Roper, and nucleon-antinucleon excitation contributions. Recent results for the choice of the meson parameters are discussed. The forces are used in Brueckner calculations and the saturation properties of nuclear matter are determined. At the high densities,the nuclear equation of state and the symmetry energy are calculated. The corresponding neutron star mass-radius relations are presented.

A method for the analysis of low-mass molecules by MALDI-TOF mass spectrometry

We report a novel method termed matrix suppressed laser desorption/ionization to improve the analysis of low-mass molecules by MALDI-TOF mass spectrometry. In this method, the surfactant of cetrimonium bromide (CTAB) is added to the conventional matrix of alpha-cyano-4-hydroxycinnamic acid solution to prepare the MALDI samples. During the MALDI process, the presence of CTAB could substantially or even completely suppress the matrix-related ion background. As a result, very clean mass spectra can be routinely obtained in the low-mass range. In addition, the presence of CTAB can significantly improve the mass resolution of low-mass molecules. It is seen that high-quality spectra were routinely obtained at a matrix/CTAB ratio of 1000:1. This method has been successfully used to analyze a variety of low-mass molecules.

科尔沁沙地两种典型乔灌木耗水特点

以科尔沁沙地典型固沙植物小叶锦鸡儿(Caragana microphylla Lam.5年生)和樟子松(Pinus sylvestris var.mongolica Litrin,7年生)为研究对象,栽植于可渗漏式生长箱,应用TDR水分仪测定生长季节土壤水分变化,依据土壤水分平衡理论推算单位面积植被区的蒸散量。经2a研究,在相同栽植密度下(1m×1m),樟子松植被区土壤贮水量高于小叶锦鸡儿植被区;在不同栽植密度下,小叶锦鸡儿土壤贮水量以1m×2m密度区高于1m×1m密度区。生长季节单位面积土壤蒸散量以小叶锦鸡儿(1m×1m)最高,小叶锦鸡儿(1m×2m)其次,樟子松(1m×1m)最低。单丛/株蒸散量以小叶锦鸡儿(1m×2m)最高,小叶锦鸡儿(1m×1m)其次,樟子松(1m×1m)最低。在试验所涉及的特定年龄阶段,小叶锦鸡儿植被区蒸散耗水量高于樟子松区,土壤水分含量低于樟子松区。生产实践中应根据植物耗水特点选择适宜的固沙物种和栽植方式,以保证人工固沙植被区土壤水分的收支平衡。

绿色食品的态势

<正> "绿色食品"系指经"中国绿色食品发展中心"认定,许可使用"绿色食品"标志的无污染、安全、优质、营养类食品。它具有三个显著的特点:1.出自良好的生态环境; 2.有规范的"从土地到餐桌"全程质量控制措施和标准;3.其标志受法律保护,是集社会效益、环境效益和经济效益为一体的产物,赋予极强的时代特征和浓厚的食品文化内涵.1.绿色食品的开发是社会与经济发展的必然产物,有重要的现实意义现代大工业和城市的发展和进