30MeV/u~(40)Ar+~(112,124)Sn反应中态布居核温度的同位旋效应

用 13单元望远镜探测器阵列测量了 30MeV u40 Ar +112 ,12 4Sn反应中小角关联粒子 ,由两体符合事件提取了α α关联函数 .用三体弹道理论模型MENEKA计算本底关联函数 ,用Monte Carlo方法计算探测效率函数 ,在扣除本底产额并考虑探测效率的修正后 ,对不同同位旋反应系统 40 Ar +112 Sn和 40 Ar+12 4Sn提取的相对态布居核温度分别是 4 .18±0 .2 50 .2 1MeV和 4 .10±0 .2 20 .2 0 MeV ;考察态布居核温度和粒子能量的关系时 ,观察到两个系统的发射温度均随着粒子能量的增加而降低 ,缺中子系统40 Ar +112 Sn中由低能时的 5 .13±0 .3 00 .2 6MeV降低到高能时的 3.87±0 .3 70 .2 9MeV ,丰中子系统 40 Ar +12 4Sn中由低能时的 5 .39±0 .3 00 .2 6MeV降低到高能时的 3.32±0 .2 80 .2 3 MeV .用激发热核衰变过程的同位旋选择性对这种同位旋相关性进行了解释

氩离子注入模拟太阳风对月岩的作用

对玄武岩和斜长岩等多种岩石样品进行了低能、超高剂量氩离子注入。氩离子能量12 0keV ,注入剂量 5× 10 18 cm2 。用X射线荧光光谱仪分析了辐照样品和未辐照样品的表面元素组成 ;用分步加热法分析了注入气体释放模式及岩石对氩气的保留能力。初步探讨了岩石对氩气的保留能力和分步加热释气模式等问题

中能重离子碰撞中的碰撞参数研究

在入射能量Ｅ为４０和１００ＭｅＶ／ｕ时，对~(１１２)Ｓｎ＋~(１１２)Ｓｎ和~(１２４)Ｓｎ＋~(１２４)Ｓｎ两个反应系统在不同碰撞参数下进行了同位旋相关的量子分子动力学模型计算，系统研究了阻塞率、线性动量转移、荷电粒子多重性、轻荷电粒子多重性、中子多重性以及束缚核总电荷Ｚ_(ｂｏｕｎｄ)随碰撞参数的变化规律，结果表明，中子多重性对碰撞参数的依赖在两个能量下都存在着明显的同位旋效应，Ｚ_(ｂｏｕｎｄ)在Ｅ为４０ＭｅＶ／ｕ时存在着同位旋效应．同时讨论了在较低和较高能量时如何更合理地确定反应事件的碰撞参数．

Effects of annealing on the photoluminescence of He ion implanted sapphire after 230-MeV Pb ion irradiation

Single crystal sapphire (Al2O3) samples implanted with 110 keV He and irradiated at 320 K by Pb-208(27), ions with energy of 1.1 MeV/u to the fluences ranging from 1 X 10(12) to 5 X 10(14) ion/cm(2) and subsequently annealed at 600, 900 and 1100 K. The obtained PL spectra showed that emission peaks centred at 375, 390, 413, and 450 nm appeared in irradiated samples. The peak of 390 ran became very intense after 600 K annealing. The peak of 390 nm weakened and 510 nm peak started to build up at 900 K annealing, the peak of 390 nm vanished and 510 nm peak increased with the annealing temperature rising to 1100 K. Infrared spectra showed a broadening of the absorption band between 460 cm(-1), and 510 cm(-1) indicating strongly damaged regions being formed in the Al2O3 samples and position shift of the absorption band at 1000-1300 cm(-1) towards higher wavenumber after Pb irradiation.

Photoluminescence of inert-gas ion implanted sapphire after 230-MeV Pb ion irradiation

In the present work the photoluminescence (PL) character of sapphire implanted with 110-keV He, Ar or Ne ions and subsequently irradiated with 230-MeV Pb was studied. The implantation was performed at 320 and 600 K using fluences from 5.0 x 10(16) to 2.0 x 10(17) ions/cm(2). The Pb ion irradiation was carried out at 320 K. The obtained PL spectra showed peaks at 375, 413 and 450 nm with maximum intensity at an implantation fluence of 5.0 x 10(16) ions/cm(2) and a new peak at 390 nm appeared in the He-implanted and subsequently Pb-irradiated samples. Infrared spectra showed a broadening of the absorption band between 460 and 510 nm indicating strongly damaged regions formed in the Al2O3 samples. A possible PL mechanism is discussed.

一维位置灵敏法拉第筒的数据获取系统

简要介绍兰州重离子加速器国家实验室320 kV高压ECR实验平台原子分子物理终端上使用的一维位置灵敏法拉第筒的数据获取系统。该系统硬件由64通道电流/电压转换放大器和PCI-6224数据采集卡构成,并通过编写LabVIEW程序,实现数据的准确、同步、实时与高速采集。经验证,该获取系统简单易用,可靠性高,完全符合设计要求。

Electrochemical polymerization and characterization of polypyrrole nanowires and nanotubules

Polypyrrole nanostructure arrays, including simultaneously large quantities of nanowires and small quantities of partially filled nanotubules have been electrochemically synthesized in home-made etched ion-track polycarbonate (PC) templates. Diameter of the prepared nanostructures varies from 45 to 320 nm with their lengths up to 30 microns. Morphological studies of these nanostructures were performed by field emission scanning electron microscopy (FESEM), high resolution transmission electron microscopy (HRTEM) and Raman spectroscopy. While optical absorption properties were studied by ultraviolet-visible-near infrared spectrophotometry (UV-vis-NIR). It has been observed that the absorption maximum of polypyrrole shifts to the longer wavelength side as the diameter of these nanostructures (nanowires and nanotubules) increases. (C) 2010 Elsevier B.V. All rights reserved.

高电荷态ECR离子源游离机制及激光应用研究

本文论述了高电荷态ECR离子源的最新进展和原理；介绍了10GHz ECR2高电荷态离子源的设计特点和调试结果。在此离子源上发现了ECR离子源的新工作模式和新约束场形，新工作模式不同于传统工作模式的地方是在ECR离子源引出端注入低能电子；推动等离子体电极到更靠近高电荷态离子的约束区域；移动等磁压面使ECR等离子体向引出区域移动。新工作模式使ECR离子束流强度大为提高，得到Ar8+离子430μA、Ar9+离子320μA、O6+离子450μA；微波利用系数增加；工作气体气耗量减少。本文对新工作模式原理进行了详细的分析和讨论，得出高电荷态ECR离子源的一个重要结论，即引出端低能电子的注入比在注入端注入更有效。 本文还进行了将连续激光蒸发技术应用到ECR离子源中的研究。在10GHz ECR2离子源中使用50W连续CO2激光蒸发金属铝，得到Al6+离子约50μA。在此基础上根据ECR离子源新工作模式原理，提出了在ECR离子源引出端使用热阴极电子枪的设想，并阐述了其工作原理和设计。在激光离子源实验中发现强激光产生的等离子体具有独特的性质，如方向性、脉冲性和漂移性。在实验中使用磁场约束激光等离子体而使离子总束流提高了5倍，并首次使用了高频再游离措施，发现效果很明显，使得离子总束流提高了3倍。由此可见，可以利用脉冲激光产生等离子体的一些特殊性质来研究和改善ECR离子源的一些基本性质。 此外，在本论文中还介绍了2.45GHz ECR离子源实验台的设计和初步调试。

Study of an electroosmotic pump for liquid delivery and its application in capillary column liquid chromatography

A packed-bed electroosmotic pump (EOP) was constructed and evaluated. The EOP consisted of three capillary columns packed in parallel, a gas-releasing device, Pt electrodes and a high-voltage power supply. The EOP could generate output pressure above 5.0 MPa and constant flow rate in the range of nl/min to a few mul/min for pure water, pure methanol, 2 mM potassium dihydrogenphosphate buffer, the buffer-methanol mixture and the pure water-methanol mixture at applied potentials less than 20 W The composition of solvent before/after pumping was quantitatively determined by using a gas chromatograph equipped with both flame ionization detector and thermal conductivity detector. It was found that there were no apparent changes in composition and relative concentrations after pumping process for a methanol-ethanol-acetonitrile mixture and a methanol-water mixture. Theoretical aspect of the EOP was discussed in detail. An capillary HPLC system consisting of the EOP, an injection valve, a 15 cm x 320 mum i.d., 5 mum Spherigel C(18) stainless steel analytical column, and an on-column UV detector was connected to evaluate the performance of the EOP. A comparative study was also carried out with a mechanical capillary HPLC pump on the same system. The results demonstrated that the reproducibility of flow rate and the pulsation-free flow property of the EOP are superior to that of mechanical pump in capillary HPLC application. (C) 2004 Elsevier B.V. All rights reserved.

Preparation and characterization of long methacrylate monolithic column for capillary liquid chromatography

Long methacrylate monolithic columns (100 cm x 320 mum i.d.) were prepared from silanized fused-silica capillaries of 320 mum i.d. by in situ copolymerization of butyl methacrylate (BMA) with ethylene dimethacrylate (EDMA) in the presence of a suitable porogen. The separation performance and selectivity of the column were evaluated and compared with a 25 cm x 320 mum i.d. column prepared in the same way by capillary high-performance liquid chromatography (mu-HPLC) The results showed that the 1 m long monolithic column can generate 33 x 10(3) plate number and exhibited good permeability, higher sample loadability, and separation capability. (C) 2004 Elsevier B.V. All rights reserved.

Thermodynamic investigation of the azeotropic mixture composed of water and benzene

The molar heat capacity of the azeotropic mixture composed of water and benzene was measured by an adiabatic calorimeter in the temperature range from 80 to 320 K. The phase transitions took place in the temperature range from 265.409 to 275.165 K and 275.165 to 279.399 K. The phase transition temperatures were determined to be 272.945 and 278.339 K, which were corresponding to the solid-liquid phase transitions of water and benzene, respectively. The thermodynamic functions and the excess thermodynamic functions of the mixture relative to standard temperature 298.15 K were derived from the relationships of the thermodynamic functions and the function of the measured heat capacity with respect to temperature.

长白山北坡植物群落复杂性的海拔梯度变化(英文)

应用梯度格局法在长白山北坡海拔700m-2600m的坡面上每100 m海拔设置一样地,共计20块样地,通过对同一群落各样方间的相异性测定,对各海拔植物群落的复杂性进行了分析。结果表明,以主林层乔木种的二元数据计算的结果,除亚高山岳桦林外,其它各海拔群落的样方间均表现出较高的相异性,特别是低海拔的阔叶红松林平均相异系数达0.74,明显高于其它植被类型;暗针叶林各群落间差异不大,相对而言1400 m群落样方间的相异性略高于其它群落,表现出过渡性群落树种组成的复杂性;岳桦林树种组成简单,样[(\267\275\274\344\322\262\261\355\317\326\263\366\275\317\270\337\265\304\\317\340\313\306\320\324\241\243)-0.1(\322\324\271\340\304\276\326\326\265\304\266\376\324\252\312\375\276\335\\274\306\313\343\265\304\310\272)]落内的相异性,虽低海拔的阔叶红松林总体上高于其它群落,但差异趋势并不像乔木种那么明显。以各草本植物与所有植物种的二元数据计算的各海拔群落内样方间的相异性,表现出非常相近的趋势,群落内样方间草本植物及所有植物种均以阔叶红松林及高山冻原差异最大,暗针叶林基本稳定于比较相近的水平。图3表1参8。

An electroosmotic pump for packed capillary liquid chromatography

An electroosmotic pump (EOP) capable of generating pressure above 3 MPa and mul/min flow rate with reverse phase mobile phases of HPLC was constructed and evaluated. The pump consisted of three parallel connected fused silica capillary columns (25 cm x 320 mum I.D.) packed with 2 mum silica materials, hollow electrodes, a high voltage DC power supply, and. a liquid pressure transducer. The EOP was applied in a capillary liquid chromatographic system for mobile phase delivery instead of a mechanical pump. Standard samples containing thiourea, naphthalene, anthracene, phenanthrene and acetonitrile were separated on a 15 cm x 320 mum I.D. 5 mum Chromasil C-18 packed capillary column with acetonitrile/water as mobile phase. (C) 2003 Elsevier Science B.V. All rights reserved.