~(29)S双质子的同时发射

<正>近年来,双质子发射的现象被广泛研究。~(29)S核最外层两个质子处于2s1/2轨道,可能存在这种奇特的行为。先前的实验表明,~(29)S+~(28)Si的总反应截面有着异常大的值。这意味着~(29)S中最后2

Experimental study of two-proton correlated emission from S-29 excited states

An experiment of a S-29 beam bombarding a Au-197 target at an energy of 49.2 MeV/u has been performed to study the two-proton correlated emission from S-29 excited states. Complete-kinematics measurements were carried out in the experiment. The relative momentum, opening angle, and relative energy of two protons, as well as the invariant mass of the final system, were deduced by relativistic-kinematics reconstruction. The Si-27-p-p coincident events were picked out under strict conditions and the phenomenon of p-p correlations was observed among these events. The mechanisms of two-proton emission were analyzed in a simple schematic model, in which the extreme decay modes like He-2 cluster emission, three-body phase-space decay, and two-body sequential emission were taken into account. Associated with the Monte Carlo simulations, the present results show that two protons emitted from the excited states between 9.6 MeV and 10.4 MeV exhibit the features of He-2 cluster decay with a branching ratio of 29(-11)(+10)%.

Kinetic energy and charge state effects in the X-ray emission of Mo surface induced by Xeq+ (q=25, 29) ions

L-shell X-ray spectra of Mo surface induced by Xe25+ and Xe29+ were measured. The X-ray intensity was obtained in the kinetic energy range of the incident ions from 350 to 600 keV. The relationship of X-ray intensity with kinetic energy of the projectile and its charge state were studied, and the simple explanation was given.

Experimental study of the two-proton correlated emission from the excited states of Ne-17,Ne-18 and S-28,S-29

A series of experiments have been performed by complete kinematics measurements to study two-proton (2p) correlated emission from the excited states of Ne-17,Ne-18 and S-28,S-29 via the Coulomb excitation by bombarding on Au-197 target. 2p and residua coincident events were picked Out under strict conditions. Visible p-p correlations were observed. It is shown that 2p can be emitted from the high-lying excited states. 2p halo may lead to 2p emission with large spectroscopy factor for the states close to or beyond the threshold.

内蒙古鄂温克族牧民砖茶型氟铝联合中毒调查

目的调查鄂温克族牧民砖茶型氟铝联合中毒病情。方法随机对鄂温克族16~55岁男女均衡62名牧民进行发、血清、尿氟铝水平及血清电解质、生物化学检查,同时检测饮水、牛奶、砖茶、奶茶等氟铝水平,并进行临床检诊和拍摄前臂、骨盆正位X线片,不饮用砖茶的16~55岁男女均衡41名居民为对照组。结果发、血清、尿铝水平牧民组分别为(24.60±9.82)mg/Kg、(0.78±0.25)、(2.84±0.65)mg/L,对照组分别为(12.50±4.55)mg/kg、(0.18±0.11)、(2.09±0.64)mg/L;发、血清、尿氟水平牧民组分别为(1.00±0.52)mg/kg、(0.10±0.10)、(2.74±1.42)mg/L,对照组分别为(1.39±1.34)mg/kg、(0.04±0.03)、(0.87±0.43)mg/L;牧民发、血、尿铝及血、尿氟显著高于对照组(P<0.01)。牧民组血清AST、LDH、HBDH、ALP显著高于对照组(P<0.01)。X线摄片牧民组氟骨症检出率50.00%,关节退行性变检出率61.29%,骨间膜骨化33.87%,疏松型改变检出率29.03%,硬化型改变检出率8.06%;对照组氟骨症检出率2.44%,退行性变检出率34.15%,疏松型改变检出率21.95%,骨间膜骨化检出率2.44%,硬化型改变2.44%,X线氟骨症、关节退行性变、骨间膜骨化牧民组均高于对照组(P<0.01)。结论内蒙古鄂温克族牧民饮茶型氟中毒病情较为严重,其发病机理较为复杂,并导致多组织、器官损伤,可能为砖茶型氟铝联合中毒。

Hydrothermal Synthesis and Luminescence of Eu-Doped Ba0.92Y2.15F8.29 Submicrospheres

The nonstoichimetric Ba0.92Y2.15F8.29 submicrospheres that piled up by nanoparticles have been prepared via a solution-based method in a hydrothermal environment. The size distribution of the submicrospheres could be tuned by varying the amount of BaCl2. The fluoride source NaBF4 plays an important role in the formation of the submicrospheres. The chelator ethylenediaminetetraacetic acid regulates the growth of the primary nanoparticles as well as the aggregated submicrospheres. The photoluminescence properties of different concentrations of Eu3+-doped Ba0.92Y2.15F8.29 were investigated and the results revealed that the 8% concentration of Eu3+ ions is the optimum doping concentration and the Y3+ ions occupy the site of inversion symmetry.

用~(29)Si固体核磁共振方法研究M—ZSM-5分子筛

杂原子ZSM-5分子筛对某些特定的催化反应具有很高的活性和选择性,因而杂原子在分子筛中的存在状态成为人们十分关注的问题,作者曾用许多结构研究方法对杂原子ZSM-5分子筛进行了表征。本文用~(29)Si MAS NMR方法研究了M-ZSM-5 (M=Ga、B、Zn、Ni)分子筛杂原子的存在状态。

PRINCIPAIS INDICADORES: AGRÍCOLAS, v. 3, n. 29, 2010.

2010

PRINCIPAIS INDICADORES: LEITE E DERIVADOS, v. 3, n. 29, 2010.

2010

PRINCIPAIS INDICADORES: MACROECONÔMICOS, v. 3, n. 29, 2010.

2010

Going global in small steps: e-internships in SMEs.

Technological developments over the last thirty years increasingly shaped the means by which we recruit, select and appraise employees. Today, technology supports more flexible and geographically dispersed working modes: From teleworkers, to virtual workers, to e-interns (also known as virtual interns). The current article describes how developments in e-HRM and changes in employment forms contribute to the development and increasing popularity of e-internships (better known as virtual internships) amongst small and medium-sized enterprises. In this paper, we reflect on the rise of e-internships across different countries and relate this to e-HRM and technological advances. We explore the opportunities and challenges. These include developing effective global talent and knowledge management practices, managing diversity as well as intellectual and social capital. We furthermore link the employment of e-internship practices to strategic organizational goals and learning. In the final section, we also critically reflect on the high investment required for e-internships to succeed. The discussion on e-internships is set in the literature on e-HRM, virtual teams and knowledge management, which is furthermore supported by interviews conducted with e-interns or internship managers. Keywords: e-internships, virtual internships, computer-mediated communication

LOCALIZED ENHANCEMENTS OF Fe+10 DENSITY IN THE CORONA AS OBSERVED IN Fe xi 789.2 nm DURING THE 2006 MARCH 29 TOTAL SOLAR ECLIPSE

Habbal, Shadia Rifai; Morgan, Huw; Johnson, Judd; Arndt, Martina Belz; Daw, Adrian; Jaeggli, Sarah; Kuhn, Jeff; Mickey, Don, LOCALIZED ENHANCEMENTS OF Fe+10 DENSITY IN THE CORONA AS OBSERVED IN Fe xi 789.2 nm DURING THE 2006 MARCH 29 TOTAL SOLAR ECLIPSE, The Astrophysical Journal, Volume 663, Issue 1, pp. 598-609