Chemistry of esters of keto acids of the acetylene series. X. Addition of amines to 3-phenylethynyl-1-quinoxalone

The reaction of 3-phenylethynyl-2-quinoxalones with aliphatic and aromatic amines gives alkyl(aryl)imines of 3-phenacylidene-2-quinoxalone, the structures of which were proved by alternative synthesis from 3-phenacylidene-2-quinoxalone and the appropriate amines.See [1] for communication IX.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 276–277, February, 1976.     

Formation of the single-phase ferromagnetic semiconductor (Ga,Mn)As by pulsed laser annealing

It is shown that (Ga,Mn)As layers formed by Mn⁺ ion implantation into GaAs and subsequent annealing by an excimer laser pulse with an energy density to 200–300 mJ/cm² feature the properties of the p-type semiconductor and ferromagnetic properties. The threshold dose of implanted ions (~10¹⁵ cm^–2) for activating Mn acceptors is determined. The sheet hole concentration and the Curie temperature increase with further increasing Mn⁺ ion dose. Hysteresis loops in the magnetic field dependences of the Hall effect, the negative magnetoresistance, and magnetic and structural studies suggest that the layers are analogues of single-phase ferromagnetic compounds (Ga,Mn)As formed by low-temperature molecular beam epitaxy.     

Temperature dependences of the ion-electron emission of glassy carbons under 30-keV argon ion irradiation

The temperature dependences (?200°C < T ≤ 350°C) of the ion-induced electron emission yield γ and the structures of modified surface layers have been studied experimentally for SU-850, SU-1000, SU-1300, SU-2000, and SU-2500 glassy carbons under high-dose 30-keV Ar⁺ and N ₂ ⁺ ion irradiation. Glassy carbons manufactured using a relatively high heat-treatment temperature T _ht exhibit a stepwise increase in the electron yield at certain annealing temperatures T _a. The same behavior is observed for graphitized carbon materials. For low-temperature glassy carbons, the electron yield exhibits a monotonic increase with increasing irradiation temperature. The observed differences are related to the occurrence of different structural types of fullerene-like nanoparticles in the low-and high-temperature glassy carbons.     

The effect of radiation damage on microstructure and ion electron emission of pyrolytic graphites

The influence of radiation damage on the microstructure of pyrolytic graphites was analyzed. The correlation between the temperature dependences of ion-induced electron emission and structural modification of UPV-1 pyrolytic graphite and highly oriented UPV-1T pyrolytic graphite under neutron and high-fluence (10¹⁷–10¹⁹ cm⁻²) (30 keV) Ar⁺ irradiation was experimentally studied and discussed.     

Formation of half-metallic MnAs and MnP layers

Half-metallic MnAs and MnP layers were grown on GaAs substrates by the laser sputtering of a metal Mn target in a hydrogen and arsine (phosphine) flow. The effect of the arsine concentration in the gascarrier and the substrate temperature (T _g = 300—450°C) on the crystal structure and electrical and magnetic properties were determined. It was shown that MnP samples grown at T _g ≥ 400°C exhibit ferromagnetic properties up to 300 K, according to Hall effect measurements.     

Formation of pyrimidin-4-one derivatives in the reaction of 6-aryl-2,2-dimethyl-1,3-dioxin-4-ones with ketene aminals

N. D. Zelenskii Institute of Organic Chemistry, Russian Academy of Sciences, 117913 Moscow. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 5, pp. 1225–1226, May, 1992.     

A simple synthesis of functionalized pyridines from 6-aryl-1,3-dioxin-4-ones and N-benzoylaminal of monoacetylketene

Translated fromIzvestiya Akademii Nauk, Seriya Khimicheskaya, No. 1, pp. 234–235, January, 1993.     

Structure of 3-(o-hydroxyphenyl) derivatives of 2-quinoxalone and 2-benzoxazinone

It is shown by IR and UV spectroscopy that the products of the reaction of o-hydroxybenzoylformic acid with o-phenylenediamine and o-aminophenol have the 3-(cyclohexa-3,5-dien-2-onylidene)quinoxalone structure rather than the 3-(o-hydroxyphenyl)-2-quinoxalone structure. 3-(o-Methoxyphenyl)-2-quinoxalone and 3-(o-methoxyphenyl)-3,4-dihydro-2H-benzo-1,4-oxazin-2-one were synthesized as model compounds.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1126–1128, August, 1977.     

Single-phase epitaxial InFeSb layers with a Curie temperature above room temperature

Physics of the Solid State - Epitaxial InFeSb/GaAs heterostructures were obtained by laser deposition in vacuum. Investigations by high-resolution transmission electron microscopy and...