Schwingungsspektren fester,flüssiger und gelöster Metallpolysulfide. II. Polysulfide Rb2Sn und Cs2Sn (n ⩾ 4) sowie Na2S4

Vibrational Spectra of Solid, Liquid, and Soluted Metal Polysulphides. II Polysulphides Rb₂S_n (n ? 4) and Na₂S₄ All compounds have been prepared from the elements in liquid ammonia. Whereas Rb₂S₄ has no defined composition, the vibrational spectra of Cs₂S₄ and their structure similar to Na₂S₄ indicate that Cs₂S₄ is a well-defined compound in contrast to former suggestions. Rb₂S₅ and Cs₂S₆ are the members with the greatest chainlength of their homologe series. While Na₂S₄ still exists of S₄^2? chains in the melt the other polysulhpides disproportionate to S₃^? radicals and probably monosulphide. In the melt of Cs₂S₆, quenched to room temperature, a double branched chain structure, the thio-analogue of dithionite, S₂S₄^2?, is suggested. All polysulphides have a mean valence frequency, which is independent of the cation and decreases with increasing chainlength.     

Natural diamonds—Major,minor and trace impurities in relation to source and physical properties

Nuclear techniques for the determination of 39 impurity elements in diamonds are described. A common impurity chemistry was found for different diamonds and is considered to reflect the composition of the magma from which they crystallised. A relatively successful attempt was made to differentiate between diamonds from three different kimberlites by the application of discriminant analysis.     

1-杂环芳酰氧基-2,8,9-三氧杂-5-氮杂-1-硅杂三环[3.3.3.0~(1,5)]十一碳烷的研究

本文合成了六个1-杂环芳酰氧基杂氮硅三环和三个1-杂环芳酰氧甲基杂氮硅三环,这些化合物均未见文献报道。通过1~H NMR、IR 和 X 射线衍射的方法,确证上述化台物为五配位结构,分子内的 N→Si 配键强度较大。这是一类低毒或中毒化合物。     

Products and mechanism of secondary organic aerosol formation from reactions of linear alkenes with NO3 radicals

Secondary organic aerosol (SOA) formation from reactions of linear alkenes with NO(3) radicals was investigated in an environmental chamber using a thermal desorption particle beam mass spectrometer for particle analysis. A general chemical mechanism was developed to explain the formation of the observed SOA products. The major first-generation SOA products were hydroxynitrates, carbonylnitrates, nitrooxy peroxynitrates, dihydroxynitrates, and dihydroxy peroxynitrates. The major second-generation SOA products were hydroxy and oxo dinitrooxytetrahydrofurans, which have not been observed previously. The latter compounds were formed by a series of reactions in which delta-hydroxycarbonyls isomerize to cyclic hemiacetals, which then dehydrate to form substituted dihydrofurans (unsaturated compounds) that rapidly react with NO(3) radicals to form very low volatility products. For the approximately 1 ppmv alkene concentrations used here, aerosol formed only for alkenes C(7) or larger. SOA formed from C(7)-C(9) alkenes consisted only of second-generation products, whereas for larger alkenes first-generation products were also present and contributions increased with increasing carbon number apparently due to the formation of lower volatility products. The estimated mass fractions of first- and second-generation products were approximately 50:50, 30:70, 10:90, and 0:100, for 1-tetradecene, 1-dodecene, 1-decene, and 1-octene SOA, respectively. This study shows that delta-hydroxycarbonyls play a key role in the formation of SOA in alkene-NO(3) reactions and are likely to be important in other systems because delta-hydroxycarbonyls can also be formed from reactions of OH radicals and O(3) with hydrocarbons.     

Low temperature ion beam irradiation of gallium films

Ga-films in the amorphous, the -Ga, and the -Ga phase have been irradiated at low temperatures with Ar-ions and He-ions at energies 275 keV and 200 keV, respectively. The -phase can be transformed into the amorphous state by Ar-ion irradiation but not by He-ion irradiation. Rather small Ar-fluences <10¹⁴ ions/cm² are sufficient. The -phase is stable with respect to irradiation with Ar- and He-ions at small fluences. The as-quench condensed amorphous phase is stable with respect to Ar-ion irradiation, however, it transforms into the -phase at He-ion irradiation. The different short range order of the - and -phase is thought to be responsible for the different behavior at ion irradiation.This work is dedicated to Professor Dr. S. Methfessel on the occasion of his 60th birthday     

高校专业设置对创新型教师培养的作用——基于组织管理系统动力学流率基本入树建模法和反馈环分析法

创新型人才培养作为高等教育发展的重要目标与创新型教师密切相关,高校专业设置对创新型教师培养有直接作用。结合教育部师范类高校评估指标体系,运用组织管理系统动力学流率基本入树逐树建模法,首先建立了折合在校生数入树T1(t)、教师人数入树T2(t)、建筑面积入树T3(t)、教学科研仪器设备值入树T4(t)、收支差积累量入树T6(t),得非专业五棵入树的子流图G1(t)。然后,建立专业设置数入树T5(t),由G1(t)和T5(t)做嵌运算,规范地得复杂的高校发展系统整体流图模型G(t)。运用枝向量行列式新增反馈环计算法,计算出G1(t)新增专业入树T5(t)新增反馈环522条,其中,新增专业设置数流位L5(t)直接作用到教师人数入树T2(t)流率R21(t)的反馈环共175条。运用关键因果链分析法,围绕高校专业设置影响创新型教师培养的反馈作用问题,对175条中2至6阶的9条有代表性的反馈环进行关键因果链分析,接着,对所得的全部关键因果链按反馈作用内容分5类,在此基础上提出对应的加大高校专业等的改革力度,提高培养创新型教师对策,为管理改革提供依据。 更多还原     

运用SD枝向量行列式反馈环计算分析新兴产业协同创新障碍——以江西省绿色光源产业为例

通过组织管理系统动力学(SD)流率基本入树建模法建立江西省绿色光源产业协同创新系统的4棵入树,利用枝向量行列式反馈环算法计算出系统的18条反馈环,然后紧密联系江西省绿色光源产业协同创新增效缓慢的问题,对全部反馈环逐条进行关键因果链分析,揭示产生制约绿色光源产业协同创新增效缓慢问题的16条关键因果链,基于关键因果链所指问题的共性,将16条关键因果链分成4类,再基于4类关键因果链生成系统发展的4条管理对策,为破解江西省绿色光源产业创新增效缓慢的问题提供决策依据。更多还原     

Jumping nanodroplets: a new route towards metallic nano-particles

The dewetting process, which appears upon laser-induced melting of flat nanostructures and leads to a jumping of the droplets off the surface, is used for deposition of nano-particles onto a second substrate. Limitations in materials and particle sizes are discussed and experimentally verified. The experiments show that a variety of metals can be deposited in a size ranging from tens up to several hundreds of nanometers.     

DFT analysis of the linkage isomerism in penta(ammine)ruthenium(II/III) complexes of benzotriazole: Natural bond orbital method approach and a comprehensive energy decomposition analysis

Penta(ammine)ruthenium benzotriazole complexes [Ru^II/III(NH₃)₅bta]^+/2+ and [Ru^II/III(NH₃)₅btaH]^2+/3+ (bta and btaH are the deprotonated and neutral form of the triazole ligand, respectively) can exhibit two linkage isomers κN1 and κN2. This system was investigated by density functional theory natural bond orbitals analysis and Su-Li energy decomposition analysis. Steric, electrostatic, exchange, repulsion, polarization, and dispersion energy components of the total metal–ligand interaction were quantitatively evaluated, and revealed that the overall metal-triazole ligand is comprised of donor–acceptor interactions like σ-donation and π-back-donation, which favors a specific isomer depending on the oxidation state of the ruthenium and the charge of the ligand. Further, activation energies (ΔG^‡) for linkage isomerization reactions were calculated. Results were correlated with experimental chemical–electrochemical data and two plausible mechanisms are discussed. © 2019 Wiley Periodicals, Inc.