具有复合埋层的新型SIMON材料的制备

采用氮氧共注入方法制备了新型的 SIMON(separation by implanted oxygen and nitrogen) SOI材料 .采用不同的制备方法分别制作出样品并进行了结构测试和分析 ,发现 SIMON材料的结构和质量对注入条件和退火工艺非常敏感 .并对各种氮氧复合注入技术做了分析和比较 ,发现氮氧分次注入可以得到更好的结构和性能     

Prebiotic synthesis of sequential peptides on the Hadean beach by a molecular engine working with nitrogen oxides as energy sources

Addressing the still open question of the prebiotic origin of sequential macromolecules (peptides, nucleic acids) on the primitive Earth, we describe a molecular engine (the primary pump), which works at ambient temperature and continuously generates, elongates and complexifies sequential peptides. This new scenario is based on a cyclic reaction sequence, whose keystep is the activation of amino acids into their N‐carboxyanhydrides (NCA) through nitrosation by NOx. This process could have taken place on tidal beaches; it requires a buffered ocean, emerged land and a nitrosating atmosphere. With the help of geochemical studies and computer simulations of atmosphere photochemistry, we show that the primitive Earth during the Hadean may have satisfied all these requirements. © 2001 Society of Chemical Industry.     

Oxidative radical generation via nitrogen dioxide dimer conversions induced by amide groups of macromolecules

The features of initiation of free radical reactions in polymers by dimers of nitrogen dioxide are considered. The conversion of planar dimers into nitrosyl nitrate in the presence of amide groups of macromolecules has been revealed. Nitrosyl nitrate initiates radical reactions in oxidative primary process of electron transfer with formation of intermediate radical cations and nitric oxide. As a result of subsequent reactions, nitrogen‐containing radicals are produced. The dimer conversion has been exhibited by estimation of the oxyaminoxyl radical yield in characteristic reaction of p‐benzoquinone with nitrogen dioxide on addition of aromatic polyamide and polyvinylpyrrolidone to reacting system. The isomerization of planar dimers is efficient in their complexes with amide groups, as confirmed by ab initio calculations. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

电子工业用高纯氮的生产

生产电子工业用高纯氮的制氮装置 ,其要点和难点是一氧化碳和氢的清除。采用一氧化碳转换炉和特殊的冷箱内流程组织 ,可以生产纯度为 99 9999%以上的高纯氮。对制取电子工业用高纯氮制氮装置与常规制氮装置加氮终端净化器两种流程进行了比较。     

Effect of functionalization and boron and nitrogen substitution on some properties of carbon nanotubes

Molecular orbital calculations of the ionization potential of single wall carbon nanotubes having donor NH₂ and acceptor NO₂ groups bonded to the side walls and ends and boron and nitrogen substituted for carbon show substantial increases in ionization potential compared to carbon nanotubes with no functional groups and no carbon substitutions. The presence of a carbon vacancy on the side wall also causes a substantial increase in the ionization potential. The effect of tube length on the ionization energy is also calculated. The calculations also suggest that at appropriate levels of boron and nitrogen doping the armchair carbon nanotubes could be high temperature organic ferromagnetic materials.     

Nitrogen dioxide effect in the reduction of nitric oxide by propane in oxidizing atmosphere

The role of nitrogen dioxide in the selective reduction of NO by propane over a Cu-MFI zeolite is investigated. NO₂ and NO reductions were carried out under similar conditions of reaction. In the presence of oxygen, the reduction of NO by C₃H₈ does not differ significantly from that of NO₂. In the absence of oxygen, the reduction of NO₂ by propane occurs with a partial decomposition of the nitric dioxide molecule. Such a decomposition leads to the formation of oxygen, which is responsible for the increase in catalytic activity by comparison with the same reaction performed with NO. NO₂ formed and released in the gas phase during the reduction of NO by propane in the presence of oxygen does not play a predominant role in the catalytic process.     

Nanoscale artifacts in RuO4-stained poly(styrene)

This research studies the effects of RuO₄ exposure on various samples of poly(styrene) (PS). Transmission electron energy-loss spectroscopy (EELS) shows a decrease in the 7 eV π-π∗ transition characteristic of aromatic rings in PS indicating that RuO₄ covalently alters aromatic character. Imaging and selected-area electron diffraction show that a layer of RuO₂ solid forms on the surface of bulk PS specimens exposed to RuO₄. High-resolution TEM imaging (HREM) shows that RuO₂ nanocrystals consistently condense on specimen surfaces, independent of the chemical nature of the specimen below. These nanocrystals modulate contrast at length scales on the order of 2-5 nm in TEM images and limit resolution at nanometer length scales.     

Electrical and optical properties of oxygen doped GaN grown by MOCVD using N2O

Oxygen doped GaN has been grown by metalorganic chemical vapor deposition using N₂O as oxygen dopant source. The layers were deposited on 2″ sapphire substrates from trimethylgallium and especially dried ammonia using nitrogen (N₂) as carrier gas. Prior to the growth of the films, an AIN nucleation layer with a thickness of about 300? was grown using trimethylaluminum. The films were deposited at 1085°C at a growth rate of 1.0 μm/h and showed a specular, mirrorlike surface. Not intentionally doped layers have high resistivity (>20 kW/square). The gas phase concentration of the N₂O was varied between 25 and 400 ppm with respect to the total gas volume. The doped layers were n-type with carrier concentrations in the range of 4×10¹⁶ cm⁻³ to 4×10¹⁸ cm⁻³ as measured by Hall effect. The observed carrier concentration increased with increasing N₂O concentration. Low temperature photoluminescence experiments performed on the doped layers revealed besides free A and B exciton emission an exciton bound to a shallow donor. With increasing N₂O concentration in the gas phase, the intensity of the donor bound exciton increased relative to that of the free excitons. These observations indicate that oxygen behaves as a shallow donor in GaN. This interpretation is supported by covalent radius and electronegativity arguments.     

Pitting corrosion of Cr–Mn–N steel in sulphuric acid media

The resistance to pitting corrosion of austenitic stainless steel Cr18Mn12N has been studied in model solutions of sulphuric acid (0.5 m) containing chloride ions (0.5 m). The cyclic potentiodynamic method has been employed to investigate the effects of chloride ions and agitation rate on the pitting and repassivation potentials. Electron and optical microscopy, electron diffraction spectroscopy and atomic absorption spectrometry have been used to detect the surface sites for pit formation and the growth of pit nuclei. The results obtained with chromium–manganese–nitrogen steel have been compared with those of austenitic Cr18Ni9 stainless steel. A similarity in pit initiation is established, while steel composition exhibits no significant effect. Cr18Mn12N steel is less prone to repassivation as compared with Cr18Ni9 steel.     

品种和加工方式对双低菜粕有效能和氨基酸有效性的影响_注

用精确饲喂技术评价了 3个品种的中国双低油菜和 1个加拿大卡诺拉的脱脂种籽和商品饼粕的能量和氨基酸的有效性。结果表明 ,4个脱脂种籽的氮校正真代谢能和氨基酸真消化率没有差异 (P >0 .0 5 ) ;而 4个商品饼粕的脱脂样品的氮校正真代谢能和氨基酸真消化率有极显著或显著差异。研究结果证实 ,不适当的加工方式不仅降低了氨基酸的有效性 ,而且影响家禽对能量的利用效率。