A fixed arc length direct current plasma torch for reduced pressure deposition of thin films

Because of its high energy density direct current(dc)thermal plasmas are widely accepted as a processing medium which facilitates high processing rates high fluxes of radical species the potential for smaller jnstallations a wide choice of reactants and high quench rates[1].A broad range of industrial processing methods have been developed based on dc plasma technology. However,nonstationary features limited new applications of dc plasma in advanced processing, where reliability£¬reproducibility and precise controllability are required£. These challenges call for better understanding of the arc and jet behavior over a wide range of generating parameters and a comprehensive control of every aspect of lhe plasma processing.

路易斯碱催化还原胺化反应研究

胺及其衍生物是很多重要生物活性分子的结构单元，是合成天然产物和手性药物的重要中间体。 直接还原胺化由于其合成步骤简单而成为制备二级胺和三级胺的简便方法。为了发展一种较为简便的直接还原胺化反应，我们把研究的重点放在开发一种简便实用的有机小分子催化方法上。由文献调研可知，现已报道的直接还原胺化方法大多是催化醛或酮与一级胺或者脂肪二级胺的直接还原胺化，而醛或酮与芳香二级胺的直接还原胺化却尚无报道。在本文中，我们发现用简单的四甲基乙二胺(TEMED)在室温下以二氯甲烷为溶剂即可催化三氯氢硅对酮和芳香二级胺之间的直接还原胺化反应，并取得了高达92%的收率。该反应条件温和，底物普适性广，各种类型的酮均可以与芳香二级胺进行直接还原胺化，并且得到比较满意的收率。 同时，我们从手性Sulfoximine出发，设计和合成了一系列的Sulfoximine类新衍生物，并将其应用于间接还原胺化反应中。遗憾的是我们并没有得到预期的不对称催化效果。 Amines and their derivatives are basic structural motifs in natural products and pharmaceuticals and highly versatile building blocks for various organic substrates. Direct reductive amination (DRA) is a convenient method for the preparation of secondary and tertiary amines owing to its operational simplicity. In an effort to develop a simple and convenient procedure for direct reductive amination reaction, we focused our study on search for a mild and efficient organocatalytic system. In the literature, there are many reports concerning DRA between aldehydes or ketones and either primary amines or secondary aliphatic amines. But there are no reports concerning DRA between aldehydes or ketones and secondary aromatic amines. In this study, we have developed a highly practical method for the synthesis of tertiary amines by the direct reductive amination of ketones and secondary aromatic amines with tetramethylethylenediamine (TEMED) as the catalyst using HSiCl3 as the reducing agent in dichloromethane (affording up to 92% yield). This method can be carried out under mild conditions and is compatible with many functional groups. A variety of ketones were efficiently aminated with secondary aromatic amines to afford the corresponding amines in good to excellent yields. Starting from chiral sulfoximine, we designed and synthesized a series of new sulfoximine derivatives and tested their efficiencies as asymmetric organocatalysts for the reduction of imines, which, unfortunately, only exhibited low catalytic activity and enantioselectivity.

Beam dynamics design of an RFQ for a planned accelerator, which uses a direct plasma injection scheme

To meet the requirements of providing high-intensity heavy ion beams the direct plasma injection scheme (DPIS) was proposed by a RIKEN-CNS-TIT collaboration. In this scheme a radio frequency quadrupole (RFQ) was joined directly with the laser ion source (LIS) without a low-energy beam transport (LEBT) line. To find the best design of the RFQ that will have short length, high transmission efficiency and small emittance growth, beam dynamics designs with equipartitioning design strategy and with matched-only design strategy have been performed, and a comparison of their results has also been done. Impacts of the input beam parameters on transmission efficiency are presented, too. (C) 2008 Elsevier B.V. All rights reserved.

DIRECT MASS MEASUREMENTS OF EXOTIC NUCLEI IN STORAGE RINGS

Mass measurements of exotic nuclei is a fast, developing field which is essential for basic nuclear physics and a wide range of applications. The method of storage ring mass spectrometry has many advantages: (1) a large amount of nuclides can be simultaneously measured; (2) very short-lived (T-1/2 greater than or similar to 50 mu s) and very rare species (yields down to single ions) can be accessed; (3) nuclides in several atomic charge states can be investigated, (4) half-life measurements can be performed with time-resolved mass spectrometry. In this contribution we concentrate on some recent achievements and future perspectives of the storage ring mass spectrometry.

Discovery of Highly Excited Long-Lived Isomers in Neutron-Rich Hafnium and Tantalum Isotopes through Direct Mass Measurements

A study of cooled Au-197 projectile-fragmentation products has been performed with a storage ring. This has enabled metastable nuclear excitations with energies up to 3 MeV, and half-lives extending to minutes or longer, to be identified in the neutron-rich nuclides Hf-183,Hf-184,Hf-186 and Ta-186,Ta-187. The results support the prediction of a strongly favored isomer region near neutron number 116.

Parton energy loss in heavy-ion collisions via direct-photon and charged-particle azimuthal correlations

Charged-particle spectra associated with direct photon (gamma(dir)) and pi(0) are measured in p + p and Au + Au collisions at center-of-mass energy root(S)(NN) = 200 GeV with the STAR detector at the Relativistic Heavy Ion Collider. A shower-shape analysis is used to partially discriminate between gamma(dir) and pi(0). Assuming no associated charged particles in the gamma(dir) direction ( near side) and small contribution from fragmentation photons (gamma(frag)), the associated charged-particle yields opposite to gamma(dir) (away side) are extracted. In central Au + Au collisions, the charged-particle yields at midrapidity (vertical bar eta vertical bar < 1) and high transverse momentum (3 < (assoc)(PT) < 16 GeV/c) associated with gamma(dir) and pi(0) (vertical bar eta vertical bar < 0.9, 8 < (trig)(PT) < 16 GeV/c) are suppressed by a factor of 3-5 compared with p + p collisions. The observed suppression of the associated charged particles is similar for gamma(dir) and pi(0) and independent of the gamma(dir) energy within uncertainties. These measurements indicate that, in the kinematic range covered and within our current experimental uncertainties, the parton energy loss shows no sensitivity to the parton initial energy, path length, or color charge.

Inclusive pi(0), eta, and direct photon production at high transverse momentum in p plus p and d plus Au collisions at root s(NN)=200 GeV

We report a measurement of high-p(T) inclusive pi(0), eta, and direct photon production in p + p and d + Au collisions at root s(NN) = 200 GeV at midrapidity (0 < eta < 1). Photons from the decay pi(0) -> gamma gamma were detected in the barrel electromagnetic calorimeter of the STAR experiment at the Relativistic Heavy Ion Collider. The eta -> gamma gamma decay was also observed and constituted the first eta measurement by STAR. The first direct photon cross-section measurement by STAR is also presented; the signal was extracted statistically by subtracting the pi(0), eta, and omega(782) decay background from the inclusive photon distribution observed in the calorimeter. The analysis is described in detail, and the results are found to be in good agreement with earlier measurements and with next-to-leading-order perturbative QCD calculations.

Drift distance survey in direct plasma injection scheme for high current beam production

In a laser ion source, plasma drift distance is one of the most important design parameters. Ion current density and beam pulse width are defined by plasma drift distance between a laser target and beam extraction position. In direct plasma injection scheme, which uses a laser ion source and a radio frequency quadrupole linac, we can apply relatively higher electric field at beam extraction due to the unique shape of a positively biased electrode. However, when we aim at very high current acceleration such as several tens of milliamperes, we observed mismatched beam extraction conditions. We tested three different ion current at ion extraction region by changing plasma drift distance to study better extraction condition. In this experiment, C6+ beam was accelerated. We confirmed that matching condition can be improved by controlling plasma drift distance.

Performance comparison of low-temperature direct alcohol fuel cells with different anode catalysts

Low-temperature polymer electrolyte membrane fuel cells directly fed by methanol and ethanol were investigated employing carbon supported Pt, PtSn and PtRu as anode catalysts, respectively. Employing Pt/C as anode catalyst, both direct methanol fuel cell (DMFC) and direct ethanol fuel cell (DEFC) showed poor performances even in presence of high Pt loading on anode. It was found that the addition of Ru or Sn to the Pt dramatically enhances the electro-oxidation of both methanol and ethanol. It was also found that the single cell adopting PtRu/C as anode shows better DMFC performance, while PtSn/C catalyst shows better DEFC performance. The single fuel cell using PtSn/C as anode catalyst at 90degreesC shows similar power densities whenever fueled by methanol or ethanol. The cyclic voltammetry (CV) and single fuel cell tests indicated that PtRu is more suitable for DMFC while PtSn is more suitable for DEFC. (C) 2003 Elsevier B.V. All rights reserved.

Direct reduction of SO2 to elemental sulfur by the coupling of cold plasma and catalyst (I)

The direct reduction of SO2 to elemental sulfur in flue gas by the coupling of cold plasma and catalyst, being a new approach for SO2 reduction, was studied. In this process, CO2 can be disassembled to form CO, which acts as the reductant under the cold plasma. With the coupling of the cold plasma and the catalyst, sulfur dioxide was selectively reduced by CO to elemental sulfur with a byproduct of metal sulfate, e.g., FeSO4. In the present work, Fe2O3/gamma-Al2O3 was employed as the catalyst. The extent of desulfurization was more than 80%, and the selectivity of elemental sulfur is about 55%. The effects of water vapor, temperature, and the components of simulated flue gas were investigated. At the same time, the coupling of thermogravimetry and infrared method and a chemical analysis method were employed to evaluate the used catalyst. In this paper, we will focus on the discussion of the catalyst. The discussions of the detail of plasma will be introduced in another paper.