نتایج جستجو برای: 4h
تعداد نتایج: 6735 فیلتر نتایج به سال:
Reaction of Meldrum's acid with 3,4-bis(chloromethyl)-2,5-dimethylthiophene (1) or 3,4-bis(bromomethyl)-2,5-dimethylthiophene (2) produces the kinetically favored C,O-dialkylation product, 1,3,7,7-tetramethyl-4H,10H-6,8,9-trioxa-2-thiabenz[f]azulen-5-one (4). Recrystallization of 4 from refluxing methanol results in the methanolysis product 5-(4-methoxymethyl-2,5-dimethylthiophen-3-ylmethyl)-2,...
Solid State Nuclear Track Detectors (SSNTDs) are used extensively for monitoring alpha particle radiation, neutron flux and cosmic ray radiation. Radon gas inhalation is regarded as being a significant contributory factor to lung cancer deaths in the UK each year. Gas concentrations are often monitored using CR39 based SSNTDs as the natural decay of radon results in alpha particles which form t...
Ni(II) and Zn(II) complexes were synthesized from tridentate 3-formyl chromone Schiff bases such as 3-((2-hydroxyphenylimino)methyl)-4H-chromen-4-one (HL1), 2-((4-oxo-4H-chromen-3-yl)methylneamino)benzoic acid (HL2), 3-((3-hydroxypyridin-2-ylimino)methyl)-4H-chromen-4-one (HL3), and 3-((2-mercaptophenylimino)methyl)-4H-chromen-4-one (HL4). All the complexes were characterized in the light of el...
We report on the growth of 4H-SiC epitaxial layer on Si-face polished nominally on-axis 2” full wafer, using Hot-Wall CVD epitaxy. The polytype stability has been maintained over the larger part of the wafer, but 3C inclusions have not been possible to avoid. Special attention has given to the mechanism of generation and propagation of 3C polytype in 4H-SiC epilayer. Different optical and struc...
Two novel 3-amino-5-(4-choloro-2-phenoxyphenyl)-4H-1,2,4-triazole derivatives were prepared and their anticonvulsant activity was measured by evaluation of the ability of these compounds to protect mice against convulsion induced by lethal doses of pentylenetetrazole (PTZ). Diazepam (Sigma) was considered as a positive control drug with anticonvulsant effect [ED50 = 1.2 (0.5-1.9) mg/Kg]. Amongs...
The transformation of the synthesized allicin, using conventional method, the influence of ultrasound and microwaves, in different organic solvents (acetonitrile, acetone, methanol, and chloroform), at various temperatures (room temperature, 45 °C, and 55 °C) was investigated. Allicin degradation kinetic was monitored by HPLC. Allicin transformation under the effect of microwaves is faster than...
Divacancy (VSiVC) centers in silicon carbide (SiC) have potential applications quantum communication and sensing due to their attractive optical spin properties. To realize many of these divacancy-based applications, it is vital that they are created prescribed locations with high accuracy. Here, we describe the production arrays divacancy 4H polytype SiC (4H-SiC) by femtosecond laser irradiati...
Suzuki cross coupling reaction is one of the most famous organic reactions 20th century’s chemistry. It deemed as in field a very effective method for making carbon–carbon bonds. has been extensively utilized synthesis many carbon molecules including complex ones.Syntheses 2-diethylamino-4H-7-(Het) aryl pyrido [1,2-a] [1,3,5] triazin-4-ones are currently under investigation order to obtain grea...
The paper studies spectral theory of Schrodinger operators H= fi2A + V on the sphere from the standpoint of integrability and separation. Our goal is to uncover the fine structure of spec H, i.e., asymptotics of eigenvalues and spectral clusters, determine their relation to the underlying geometry and classical dynamics and apply this data to the inverse spectral problem on the sphere. The prot...
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