Luminescent properties of gallium nitride and gallium-aluminum nitride

Translated from Zhurnal Prikladnoii Spektroskopii, Vol. 55, No. 5, pp. 861–863, November, 1991.     

Electrical transport and magnetic ordering in R 2Ti3Ge4 (R=Dy, Ho and Er) compounds

New R ₂Ti₃Ge₄ (R=Dy, Ho and Er) intermetallic compounds have been synthesized and characterized by X-ray diffraction and low temperature ac magnetic susceptibility, electrical resistivity and thermoelectric power measurements were carried out. The compounds crystallize in the parent, Sm₅Ge₄-type orthorhombic structure (space group Pnma) and lanthanide contraction is observed as one moves along the rare-earth series. The changeover from paramagnetic to antiferromagnetic phase happens at low temperatures and the ordering temperature scales with the de Gennes factor. The electrical resistivity is metallic with a negative curvature above 100 K. Thermopower displays a weak maximum at temperatures less than 50 K signifying the possible phonon and magnon drag effects.     

Pyridoxal reactions with amines and aliphatic diamines

Interaction of pyridoxal (3-hydroxy-5-hydroxymethyl-2-methylisonicotinaldehyde) with amines, mono- and disubstituted diamines led to the formation of compounds having in their structure imine, imidazolidine, and pyrimidine moieties. Structure of the obtained compounds was proved by IR data, ¹H NMR spectroscopy, mass spectrometry, and X-ray diffraction analysis.     

Reaction of 3-methoxy-2-methylphenol with 2-ethoxyvinylphosphonic dichloride

Condensation of 2-ethoxyvinylphosphonic dichloride with 3-methoxy-2-methylphenol in dioxane in the presence of trifluoroacetic acid results in 5,13-dimethoxy-4,14-dimethyl-1-phospha-2,16-dioxatetracyclo[7.7.1.0^3,8.0^10,15]heptadeca-3,5,7,10,12,14-hexaene 1-oxide and 2-hydroxy-7-methoxy-8-methyl-2-oxobenzo[e]-1,2-oxophosphorine.     

氩气等离子体射流诱导水生成OH自由基的研究

·OH在众多领域中具有非常重要的作用,在国际上引起了广泛关注,而大气压等离子体射流由于不需要真空、装置简单易于携带,且具有高浓度活性粒子、高电子温度、低射流温度等优点,具有极强的应用前景,成为气体放电领域的重要研究课题。特别是如何诱导等离子体射流中·OH的产生已成为等离子体射流领域一个新的研究热点。国外率先报道了将水蒸汽以一定的比例混入等离子体射流工作气体中以诱导产生大量·OH的研究,然而当含水量较高时,射流会剧烈摆动,放电变得十分不均匀、不稳定。为此,本文设计了一种大气压双环电极氩气等离子体射流诱导水产生·OH的装置,通过引入超声雾化装置增加等离子体羽周围的湿度以提高·OH含量,重点研究了不同电压、流量下诱导水生成OH(A2Σ+)的生成规律;利用发射光谱法测试了装置产生·OH的含量;并利用810.41和811.48 nm这两条Ar原子光谱线,计算了等离子体羽中的电子温度。结果表明等离子体羽可以诱导周围的水产生·OH,且随电压从20 kV增大到28 kV时,OH(A2Σ+)的产量逐渐增大;而当氩气流量从100 L·h-1增大到200 L·h-1时,·OH产量随着流量的增大而增大,但是当氩气流量从200 L·h-1增大到600 L·h-1时,·OH产量随着流量的增大而不断减小。OH(A2Σ+)的产量和电子温度变化趋势完全一致,证明了·OH的产量主要受电子温度的影响。     

Synthesis of novel 1,2,3-triazolyl nucleoside analogues bearing uracil, 6-methyluracil, 3,6-dimethyluracil,thymine, and quinazoline-2,4-dione moieties

A series of novel 1,2,3-triazolyl nucleoside analogues was synthesized via the CuAAC reaction of N1-alkynyl uracil, 6-methyluracil, 3,6-dimethyl uracil, thymine and quinazolin-2,4-dione with protected azido β-d-ribofuranose. The obtained compounds differ in both the nature of the pyrimidine-2,4-dione fragment and the length of the polymethylene linker connecting it with the β-d-ribofuranosyl-1,2,3-triazol-4-yl moiety. The 1,2,3-triazolyl nucleoside analogues were evaluated for their cytotoxicity in vitro.