The influence of carbon ion irradiation on sweet sorghum seeds

The aim of this study is to investigate the effects of different doses of 100 MeV/u carbon ions on sweet sorghum seeds in order to improve crop yields and their sugar content. After irradiation, seeds were germinated and grown to 30 days, and others were sown in the field. At the end of harvesting season all planted seeds were picked separately and M2 generations obtained. The differences among the treatments were examined using the RAPID procedure. In the study done by using 38 primers; according to the amplification results, the differences among the various doses treatment were shown.

Rotation-driven prolate-to-oblate shape phase transition in W-190: A projected shell model study

A shape phase transition is demonstrated to occur in W-190 by applying the projected shell model, which goes beyond the usual mean-field approximation. Rotation alignment of neutrons in the high-j, i(13/2) orbital drives the yrast sequence of the system, changing suddenly from prolate to oblate shape at angular momentum 10h. We propose observables to test the picture.

Structural and PL properties of Cu-doped ZnO films

Cu-doped ZnO films with hexagonal wurtzite structure were deposited on silicon (1 1 1) substrates by radio frequency (RF) sputtering technique. An ultraviolet (UV) peak at similar to 380nm and a blue band centered at similar to 430nm were observed in the room temperature photoluminescent (PL) spectra. The UV emission peak was from the exciton transition. The blue emission band was assigned to the Zn interstitial (Zn-i) and Zn vacancy (V-Zn) level transition. A strong blue peak (similar to 435 nm) was observed in the PL spectra when the alpha(Cu) (the area ratio of Cu-chips to the Zn target) was 1.5% at 100 W, and ZnO films had c-axis preferred orientation and smaller lattice mismatch. The influence of alpha(Cu) and the sputtering power on the blue band was investigated.

Separation of potential and kinetic electron emission from Si and W induced by multiply charged neon and argon ions

T he total secondary electron emission yields, gamma(T), induced by impact of the fast ions Neq+ (q = 2-8) and Arq+ (q = 3-12) on Si and Neq+ (q = 2-8) on W targets have been measured. It was observed that for a given impact energy, gamma(T) increases with the charge of projectile ion. By plotting gamma(T) as a function of the total potential energy of the respective ion, true kinetic and potential electron yields have been obtained. Potential electron yield was proportional to the total potential energy of the projectile ion. However, decrease in potential electron yield with increasing kinetic energy of Neq+ impact on Si and W was observed. This decrease in potential electron yield with kinetic energy of the ion was more pronounced for the projectile ions having higher charge states. Moreover, kinetic electron yield to energy-loss ratio for various ion-target combinations was calculated and results were in good agreement with semi-empirical model for kinetic electron emission.

Structural and photoluminescent properties of ZnO films deposited by radio frequency reactive sputtering

Zinc oxide films with c-axis preferred orientation were deposited on silicon (100) substrates by radio frequency (RF) reactive sputtering. The properties of the samples were characterized by X-ray diffractometer, X-ray photoelectron spectroscopy and fluorescent-spectrophotometer. The effect of sputtering power and substrate temperature on the structural and photoluminescent (PL) properties of the ZnO films was investigated. The results indicated that when the sputtering power is 100 W and the substrate temperature is 300-400 degrees C, it is suitable for the growth of high c-axis orientation and small strain ZnO films. A violet peak at about 380 nm and a blue band at about 430 nm were observed in the room temperature photoluminescence spectra, and the origin of blue emission was investigated.

低能He~(2+)与He原子碰撞转移电离出射电子能谱研究；Investigation on Electron Energy Spectra of Transfer Ionization Process in 70 and 100 keV He~(2+) Colliding on He

利用反应显微成像谱仪对70和100keV He2+与He原子碰撞转移电离(TI)过程中不同出射角度的电子能谱进行了测量,观测到出射电子能谱具有如下分布特征:出射电子速度分布介于0和入射离子速度vp之间;在不同出射角度电子能谱分布均有一极大值存在,随着出射角度的增大,能谱分布极大值逐渐减小;当电子出射角度等于45°时,多数电子集中在0eV附近。上述特征可由低能离子-原子碰撞"准分子"模型进行定性解释。在100keV He2+-He转移电离出射电子能谱中有靶电子被俘获至散射离子连续态(electron capture to continuum,简称ECC)电子的贡献,这可看做是动力学两步过程的作用。

Ultrahigh compression of water using intense heavy ion beams: laboratory planetary physics

Intense heavy ion beams offer a unique tool for generating samples of high energy density matter with extreme conditions of density and pressure that are believed to exist in the interiors of giant planets. An international accelerator facility named FAIR (Facility for Antiprotons and Ion Research) is being constructed at Darmstadt, which will be completed around the year 2015. It is expected that this accelerator facility will deliver a bunched uranium beam with an intensity of 5x10(11) ions per spill with a bunch length of 50-100 ns. An experiment named LAPLAS (Laboratory Planetary Sciences) has been proposed to achieve a low-entropy compression of a sample material like hydrogen or water (which are believed to be abundant in giant planets) that is imploded in a multi-layered target by the ion beam. Detailed numerical simulations have shown that using parameters of the heavy ion beam that will be available at FAIR, one can generate physical conditions that have been predicted to exist in the interior of giant planets. In the present paper, we report simulations of compression of water that show that one can generate a plasma phase as well as a superionic phase of water in the LAPLAS experiments.

Excitation and dissociation of tungsten hexacarbonyl W(CO)(6): Statistical and nonstatistical dissociation processes

We have studied the excitation and dissociation processes of the molecule W(CO)(6) in collisions with low kinetic energy (3 keV) protons, monocharged fluorine, and chlorine ions using double charge transfer spectroscopy. By analyzing the kinetic energy loss of the projectile anions, we measured the excitation energy distribution of the produced transient dications W(CO)(6)(2+). By coincidence measurements between the anions and the stable or fragments of W(CO)(6)(2+), we determined the energy distribution for each dissociation channel. Based on the experimental data, the emission of the first CO was tentatively attributed to a nonstatistical direct dissociation process and the emission of the second or more CO ligands was attributed to the statistical dissociation processes. The dissociation energies for the successive breaking of the W-CO bond were estimated using a cascade model. The ratio between charge separation and evaporation (by the loss of CO+ and CO, respectively) channels was estimated to be 6% in the case of Cl+ impact. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3523347]

10～100 MeV/u能区重离子反应机制的研究

把QMD模型扩展至10～100MeV/A能区，研究了该能区的重离子碰撞，并仔细检验了初始核在基态时传播的稳定性条件。~(40)Ca+~(40)Ca系统，在10 ～ 100MeV/A能区范围内研究了重离子反应机制随入射能量及碰撞参数的演化情况。我们发现，反应机制随能量的变化并不是突然的跃迁，而是一个连续的变化过程，不同的反应机制可以同时存在并发生竞争。在中心碰撞时，反应机制从全融合发展至非全融合，最后演化至碎裂机制。在周连碰撞时，随着入射能量的增加，根据我们提出的关于深部非弹碰撞和参加者－旁观者质量分布的判据，反应机制的可能变化趋势为从非完全融合或深部非弹碰撞到参加者－旁观者，最后发展至碎裂反应。我们知道，目前还没有人用QMD模型来研究过渡能区DIC机制的基本特征，我们还对~(20)(25Mev/A)+~(20)Ne系统周边碰撞时DIC机制的基本特征作了研究，计算结果表明：在中能区，DIC机制仍然存在，同时，在质量分布、旋转效应及能量损失方面具有低能时相同的特征，但与低能DIC的明显差别在于，出射的中间质量碎片已成为质量分布的主要部分，出射的轻粒子数目也相对增多。当碰撞参数小于7fm时，这里存在着不同反应机制的共存及竞争。根据质量分布随时间的演化情况，我们发现，中间质量碎片主要是由动力学过程中平均场涨落引起的动力学不稳定性造成的，统计衰变也贡献较小的一部分。由粗糙估计可以看出，25MeV/A时~(20)Ne+~(20)Ne系统的DIC机制仍然是一个趋向于平衡过程。相又于低能区，中能区的周边碰撞显得相当复杂

重离子与~(nat)W相互作用中Hf的生成研究

用放射化学方法研究了6.3、8.5、11.8、14.7、18.4、24.6、40 MeV/nucleon ~(40)Ar + ~(nat)W、10.5 MeV/nucleon ~(84)Kr + ~(nat)W、80 MeV/nucleon ~(16)O + ~(nat)W、135 MeV/nucleon ~(12)C + ~(nat)W反应中的Hf的生成，得到了Hf同位素的激发函数、反冲性质和同位素分布。研究结果指出利用HIRFL能量的重离子和丰中子靶核作用，能以一定的截面生成A > 170区丰中子新核素。重炮弹更有利于丰中子新核素的生成。使用厚靶，可以明显地提高丰中子新核素的产额。过高的入射能量对丰中子新核素的生成无明显贡献，相反却极大地增加了缺中子同位素产额，这对丰中子新核素的分离和鉴别是非常不利的

SFC 200K W高频系统计算机控制的改进探讨

本文是关于对HIRFL SFC 200KW 高频系统实施计算机控制的专题讨论。首先对HIRFL SFC 200KW 高频系统各部分的运行情况进行了详细分析，在此基础上对原有计算机控制系统进行了剖解，并针对原有计算机控制系统存在的缺陷进行了一些改进和实验，使之投入实际运行工作中；然后，对计算机控制系统中普遍采用的电路从理论上进行了讨论，给出了一些有益于工程实践的结论；最后，为了实现对整个SFC 200KW 高频系统的计算机控制，从软、硬件两个方面，提出了对HIRFL SFC 200KW 高频系统进行该造的方案。