Influence and determinative factors of ion-to-atom arrival ratio in unbalanced magnetron sputtering systems

Low pressure sputtering with a controlled ratio of ion flux to deposited atom flux at the condensing surface is one of the main directions of development of magnetron sputtering methods. Unbalanced magnetron sputtering, by producing dense secondary plasma around the substrate, provides a high ion current density. The closed-field unbalanced magnetron sputtering system （CFUBMS） has been established as a versatile technique for high-rate deposition high-quality metal, alloy, and ceramic thin films. The＇key factor in the CFUBMS system is the ability to transport high ion currents to the substrate, which can enhance the formation of full dense coatings at relatively low value homologous temperature. The investigation shows that the energy of ions incidenced at the substrate and the ratio of the flux of these ions to the flux of condensing atoms are the fundamental parameters in determining the structure and properties of films produced by ion-assisted deposition processes. Increasing ion bombardment during deposition combined with increasing mobility of the condensing atoms favors the formation of a dense microstructure and a smooth surface.

Speciation Analysis of Arsenic Compounds in Seafood by Ion Chromatography-Atomic Fluorescence Spectrometry

Ion chromatography-ultra violet-hydride generation-Atomic Florescence Spectrometry was applied to detect 5 arsenic species in seafoods. The arsenic species studied include arsenobetaine(As B), arsenite(As(III)), dimethylarsinic acid(DMA), monomethylarsonic acid(MMA), and arsenate(As(V)), which were extracted from samples using 2% formic acid. Gradient elution using 33 mmol L^(-1) CH_3COONH_4 and 15 mmol L^(-1) Na_2CO_3 with 10 mL CH_3CH_2OH at pH 8.4 allowed the chromatographic separation of all the species on a Hamilton PRP-X100 anion-exchange column in less than 8 min. In this study, an ultrasound extraction method was used to extract arsenic species from seafood. The extraction efficiency was good and the recoveries from spiked samples were in the range of 72.6%–109%; the precision between sample replicates was higher than 3.6% for all determinations. The detection limits were 3.543 μg L^(-1) for As B, 0.4261 μg L^(-1) for As(III), 0.216 μg L^(-1) for DMA, 0.211 μg L^(-1) for MMA, and 0.709 μg L^(-1) for As(V), and the linear coefficients were greater than 0.999. We also developed an application of this method for the determination of arsenic species in bonito, Euphausia superba, and Enteromorpha with satisfactory results. Therefore, it was confirmed that this method was appropriate for the detection of arsenic species in seafood.

Experimental study of cross-section ratios in the collisions of C^(q+) and O^(q+) (q=1-4) on atomic helium in strong-interaction region

We have measured the cross-section ratios of helium induced by Cq＋ and Oq＋ （q = 1-4） in an energy range from 20 keV/amu to 500 keV/amu, and obtained the two-dimensional spectra by employing the coincidence method combined with the MPA-3 data acquisition system. Hence, we obtain the ratios of total single-ionization cross-sections （SI, SC, SLSI, and DLSI）, total double-ionization cross-sections （DI, DC, TI, SLDI, and DLDI） and cross-sections of every process （SI, SC, SLSI, DLSI, DI, DC, TI, SLDI, and DLDI）, which induce the single-ionization and double-ionization, to the total cross sections respectively. The competitive relations between the reaction-channels and the experimental data law of each reaction-channel are revealed explicitly, and the qualitative explanations involved in those results are also presented accordingly.

On-line Preconcentration and Determination of Trace Metals in Water Samples by Flow Injection Combined with Flame Atomic Absorption Spectrometry via Calix[4]arene Carboxylic Acid Packed Micro-column

An adsorbent calix[4]arene carboxylic acid was employed as the adsorption material for on-line flow in jection（FI） micro-column preconcentration coupled with flame atomic absorption spectrometry（FAAS） determination of trace heavy metals（Cu, Pb, Co, Ni and Cd）. Parameters such as the pH, loading time and flow rate of sample, and the concentration, volume and flow rate of eluent were optimized. The enrichment factors are 50.0, 56.5, 11.6, 12.1 and 19.1 for Cu, Pb, Co, Ni, and Cd, respectively, and a sample throughput of 20 h–1 was obtained. The limits of de tection for Cu, Pb, Co, Ni, and Cd were in a range of 1.56―3.91 μg/L, and the relative standard deviations（RSDs） were less than 2.76%（n=7）. Furthermore, the proposed method was successfully applied to the determination of Cu, Pb, Co, Ni, and Cd in certified reference materials and various water samples.

Ground-based Investigations of Atomic Oxygen Erosion Behaviors of Silver and Ion-implanted Silver

Silver foils and ion-implanted silver foils exposed to atomic oxygen （AO） generated in a ground simulation facility were investigated by the quartz crystal microbalance （QCM）, the scanning electron microscopy （SEM） and the X-ray photoelectron spectroscopy （XPS）. The experimental results show the presence of Ag2O and AgO in an oxidation process of the silver foil having exposure to AO. As soon as silver comes under the bombardment of atomic oxygen, the oxidation process starts with a thick film forming on the silver surface. Because of the development of stresses, the oxide layer gets cracked and spalled, which leads to appearance of a new silver surface intensifying further oxidation. At last, AgO begins to form on the outer surface of the oxide film. The analytical results of the XPS and the AES attest to formation of a continuous high-quality protective oxide-based layer on the surface of ion-implanted silver films after exposure to AO. This layer can well protect materials in question from erosion.

ACCELERATOR-BASED ATOMIC PHYSICS AT THE LAWRENCE BERKELEY LABORATOTY:COLLISIONS OF FAST,HIGHLY-CHARGED IONS WITH ATOMS

Research on accelerator-based atomic physics at the Lawrence Berkeley Laboratory super-HILAC and Bevalac accelerators is described. This research covers several important topics in collisions of fast, highly charged ions with atoms: charge transfer, ionization, and excitation. Multiple - electron processes are emphasized. Electron correlation is important in some of these processes, e.g., resonance transfer and excitation (RTE) multiple-electron capture in close collisions. A variety of experiments and results for energies from 1 to 420 MeV/u are presented.

EXPERIMENTS OF MeV ION BEAM INDUCED ATOMIC MIXING

An experimental apparatus for studies of MeV ion beam modification of materials has been established on a 3 MV tandem accelerator at Fudan university. A system of X-Y electrostatic scanning implantation of MeV heavy ions and in situ Rutherford. backscattering analysis was included in it. The uniformity of scanning implantation was checked by the RBS measurement of a Si wafer implanted with 1 MeV Au ions. MeV ion beam mixing of Au/Si, Au/Ge and Ag/Si systems was preliminarily studied. The samples were irradiated by certain fluences of 1 MeV Ag ions at room temperature. The mixed layers were analyzed in situ using the glancing RBS technique with 2 MeV 4He+ ions. For Au/Si system, a uniformly mixed layer with a defined composition is obtained, and the intermixing is much less for Ag/Si system than for Au/Si system.

Comparison of Simulation Methods of Ion-Atomic Collisions in PIC-MC

The main ion-atomic collision treatment methods based on Monte-Carlo simulation are considered and discussed. We have proposed an efficient scheme for simulation of time between collisions taking into account cross-section dependence on ion velocity and random generation of ion velocities and scattering angles after collisions. The developed algorithm of simulation of interval between collisions takes into account the change of relative velocity of ion-atom pair as well as the change of cross-section of collision and atomic concentration. At the same time, unlike the widely used “null-collision” method, both the probability of collision and change of particles’ state which determines this probability are taken into consideration for each particle independently in time. The simulation results according to the techniques proposed are found to be close to the theoretical values of ion drift velocities. It is revealed that the “null-collision” method results in exceeding of drift velocity in strong and intermediate fields. At the same time the proposed method of accumulation of probability under the same conditions gives values close to theoretical ones. In weak fields calculated values of drift velocity in both methods exceed theoretical values to some small extent.

Intrinsic Decoherence of a Two-Atom System with Dipole-Dipole Interaction

我们在由二个二水平的原子和一个光洞组成的一个系统的内在的 decoherence 上调查偶极子偶极子相互作用的效果。系统的纠纷被使用同时发生计算。我们的结果证明为偶极子偶极子相互作用的联合经常的终止的适当选择能制止系统的内在的 decoherence。我们也发现特殊现象。不管鲸鱼群妈的价值是什么，系统的同时发生慢慢地增加并且不能超过 0.71 什么时候终止 = 1。

THE STUDIES OF SURFACE LAYER ATOMIC STRUCTURE OF AL(100) BY MEV ION SCATTERING

A UHV system specially designed for studying surface and interface atomic structure by MeV ion scattering and channeling is described. The vacuum in the UHV chamber is 133.332×10-10Pa. The chamber is equipped with an ion gun used for sample cleaning, a translatable four-grid LEED-Auger system used for characterization of the crystal surface, and a three dimensional goniometer. The crystal preparation and cleaning procedure of Al(100) are presented. The surface peak intensity of Al(100)-【100】 and Al(100)- 【100】 has been measured by MeV ion channeling and scattering. The measured surface peak intensity was compared with that of Monte-Carlo simulation. The experimental results indicate that the thermal vibration amplitude of Al(100) surface atoms is 1.2 -1.3 times that of bulk atoms. The relaxation of first layer for Al(100) is less than -0.005nm.

Semiclassical Approach to Non-Sequential Double Ionization of Diatomic Molecules in Strong Laser Field

我们开发一个半古典作品模型描述两价的分子的非顺序的双电离在一强烈线性地极化了成立，在电离动力学完成卓见进 thetwo 电子关联效果。比作氮分子的试验性的数据，我们的模型在在障碍上政体在掘的政体和一个质的协议显示出一个好协议。我们结束古典 collisional 轨道是在掘的政体的双电离的主要来源。作为我们的理论的预言，我们也为氢分子计算 H-2 (2+)/H-2 (+) 的双电离比率并且预言比率不到氮分子的。

Numerical Investigation of the Tri-Atomic Ions Formation during Laser Ionization Based on Resonance Saturation

We present a theoretical investigation of plasma generation in sodium vapor induced by laser radiation tuned to the first resonance line (3S-3P) at λ = 589 ns. A set of rate equations that describe the rate of change of the ground and excited states population as well as the temporal variation of the electron energy distribution function (EEDF), beside the formed atomic ion Na+, molecular ion ?and tri-atomic ions are solved numerically. The calculations are carried out at different laser energy and different sodium atomic vapor densities under the experimental conditions of Tapalian and Smith (1993) to test the existence of the formed tri-atomic ions. The numerical calculations of the electron energy distribution function (EEDF) show that a deviation from the Maxwellian distribution due to the super elastic collisions effect. In addition to the competition between associative ionization (3P-3P), associative ionization (3P-3D) and Molnar-Horn- beck ionization processes for producing , the calculations have also shown that the atomic ions Na+ are formed through the Penning ionization and photoionization processes. These results are found to be consistent with the experimental observations.

Modified Atomic Orbital Theory of the O+ Ion Originating from 2D0 and 4S0 Metastable States

We report in this paper energy positions of the 2D0_2s22p2(1D)nd(2F);2D0_2s22p2(1D)nd(2D);2D0_2s22p2(1D)nd(2P);2D0_2s22p2(1D)ns(2D);2D0_2s22p3(3D)np(2P);2D0_2s22p3(3D0)np(2F), and 4S0_2s22p3(5S0)np(4P) Rydberg series in the photoionization spectra originating from 2D0 and 4S0 metastable states of O+ ion. Calculations are performed up to n = 20 using the Modified Orbital Atomic Theory (MAOT) [1]. The present results are compared to the experimental data of Aguilar et al. [2] which are the only available values. The accurate data presented in this work may be a useful guideline for future experimental and other theoretical studies.

Motion Characteristics of Single Electrons of Atoms of Atomic Gas of Hydrogen and Single Electrons of Hydrogen-Like Ions in Form Gas or Vapour during Decays of Such Atoms and Ions. Emission Line Spectra

For the first time the vector differential equation of central motion of single electron in electric field of an atomic nucleus as in external central electric field is set up and solved. Here the following findings are reported. Each of single electrons of a part of atoms of atomic gas of hydrogen and a part of hydrogen-like ions in the form of a gas or a vapour revolves around corresponding atomic nucleus in a flat spiral which has an interior maximum of turns density. The distance between each of these single electrons and corresponding atomic nucleus increases while a speed of single electron decreases. Such motion of single electrons takes place with no expenditures of external energy and points to decays of foregoing parts of atoms and ions. The electric field strength of the atomic nuclei of atoms of atomic gas of hydrogen and hydrogen-like ions in the form of a gas or a vapour is inversely proportional to the distance between the atomic nucleus and the corresponding single electron by greater than the power of 3. Calculated cyclic frequency (rough value 3.5×1014 s-1) of revolution of the electron around the nucleus of atom of atomic gas of hydrogen (in interior maximum of turns density of the flat spiral), which moves at speed 2.2×106 ms-1, and central cyclic frequency of α-line of Balmer series (4.5×1014 s-1) have the same order of magnitude. This fact and line structure of experimental emission line spectra confirm the formation of all lines of these spectra by continuous slight emission of light front by single electrons. The formation of series of lines of emission line spectra is linked to repeated creations of atoms of atomic gas of hydrogen and hydrogen-like ions in the form of a gas or a vapour.

Determination of Atomic Fraction of Isotope Carbon-13 Directly in Urea, Benzophenone, Nitrobenzene, Benzoic Acid and 2-Hydroxybenzoic Acid

The possibility of determining atomic fractions of the isotopes of carbon directly in urea, nitrobenzene, benzophenone, benzoic acid and 2-Hydroxybenzoic acid in compounds isotopically modified by all carbon centers, as well as by one or several identical carbon centers is considered. The mass peaks of the mass spectrum that allows determining the atomic fraction of carbon isotopes are selected. The respective formulas are proposed. Until now, isotope analysis of these compounds has been carried out by converting them to carbon monoxide or dioxide, and it has been impossible to determine the atomic fraction of carbon at individual centers.

原子力显微镜-扫描电子显微镜共定位表征系统的研发与应用

微纳加工过程中,常有样品需要进行聚焦离子束(FIB)溅射、切割,扫描电子显微镜(SEM)以及原子力显微镜(AFM)表征,而这三类仪器都需要将样品固定在样品台上才可测试,固定不佳会影响表征结果.但固定好的样品在不同仪器之间转移、拆卸、再固定的过程中极易受到破坏.基于以上问题,设计了AFM-SEM-FIB样品共定位系统,可实现样品在此三种仪器之间的无损转移及共定位,避免珍贵样品破坏及目标丢失,以及解决AFM扫描无法控制方向、迅速调整位点等问题.在微纳表征中有优异的表现,系统已被开发成产品并量产销售.

低浓度聚丙烯酰胺含量的检测及溶液离子的影响

处理后选矿废水中残余的聚丙烯酰胺(PAM)影响回水水质及其回用,本文为建立一种低检出限的低浓度PAM快速检测方法,在190~300 nm波长范围内建立了4种类型及分子量不同PAM的紫外吸收光谱,研究了不同浓度K^(+)和Ca^(2+)对PAM浓度检测的影响,并通过原子力显微镜(AFM)分析了PAM分子构象的变化.结果表明,4种类型的PAM峰值吸光度均在波长194 nm处测得,PAM浓度与吸光度之间具有强线性关系(R^(2)>0.98),检出限均低于0.1 mg·L^(-1),但PAM类型影响其浓度与吸光度的线性关系.随着K^(+)和Ca^(2+)浓度的增加,PAM溶液吸光度特征峰的强度逐渐降低并降速减缓,最大吸收波长不断红移,分别沉积在二氧化硅和金基底的APAM-3与CPAM-12的表面形貌粗糙度分别随K^(+)和Ca^(2+)浓度的增加而增大,说明PAM分子链在溶液中的构象逐渐变卷曲,使紫外光谱特征吸收峰的峰值降低,10、100 mmol·L^(-1) K^(+)与1、10 mmol·L^(-1) Ca^(2+)对PAM构象变化的影响程度基本相同.本研究实现聚丙烯酰胺的快速定量检测,对开展选矿水处理中聚丙烯酰胺的迁移规律研究具有重要意义.

人血白蛋白铝离子残留现状分析

目的 探究人血白蛋白中铝离子的出厂值及货架期内残留现状,并重点考察产品使用的玻璃瓶质量提升情况,为该产品的包材使用评价提供参考。方法 采用原子吸收法测定2023年人血白蛋白样品并与2018年人血白蛋白国家抽检研究数据进行比较;通过加速试验比较国内两家药用玻璃瓶中样品铝含量变化,考察玻璃瓶质量。结果 8家企业2023年铝离子出厂值较2018年明显下降(下降率31%~75%);2023年货架期内国内产品铝残留较2018年平均下降65%;2023年使用的两种玻璃瓶铝离子释放量较2018年下降率分别为78%与25%。结论 人血白蛋白产品出厂检验和国家抽检铝残留,以及国内两家重点药品包材生产企业玻璃瓶加速试验样品铝残留均下降,说明国产玻璃瓶质量提升,建议生产企业持续关注产品的包材使用与相容性研究。

磷酸锰铁锂正极材料研究进展

作为锂离子电池正极材料之一,磷酸锰铁锂具有能量密度大、安全性好、成本较低等优点,被认为是磷酸铁锂理想的升级品。但是,磷酸锰铁锂较低的电导率和Li^(+)扩散系数限制了其商业化应用。介绍了磷酸锰铁锂材料性能,总结了高温固相法、共沉淀法、溶胶凝胶法、水热/溶剂热法等合成方法的优缺点,综述了碳包裹、纳米化及形貌控制、离子掺杂等改性策略,指出磷酸锰铁锂材料应具有一个合适的锰铁原子数量比;在总结前人研究成果的基础上,展望了未来磷酸锰铁锂正极材料的研究方向。

同步辐射在原子分子物理研究中的应用

同步辐射是电子以接近光速做圆周运动或蛇行运动时,沿着运动轨道的切线方向发出的电磁辐射,或称为光。这种辐射覆盖了从红外线到硬X射线的宽幅波段,并且具有亮度高、相干性好等优点。特别是在软X射线和硬X射线波段,同步辐射光源是唯一兼具高亮度和波长可调谐的光源,为研究原子分子与光子的相互作用过程提供了高度精细的实验利器,并由此打开解析微观世界新的大门。文章从同步辐射的产生过程剖析其关键要素,并综述了同步辐射在原子分子物理研究中的最新进展。