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RISS 인기검색어
- 검색키워드
- 저자 : N.S. Abd El-Aal (검색결과 3 건)
- 무료
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El Gaby, Mohamed S.A.,Kamal El Dean, Adel M.,Gaber, Abd El Aal M.,Eyada, Hassan A.,Al Kamali, Ahmed S.N. Korean Chemical Society 2003 Bulletin of the Korean Chemical Society Vol.24 No.8
Condensation of 4-cyano-5,6-dimethyl-3-pyridazinone 1 with aromatic aldehydes gave the novel styryl derivatives 2a-c. Refluxing of compound 2a with phosphorus oxychloride furnished 3-chloropyridazine derivative 3. Compound 3 was reacted with thiourea and produced pyridazine-3(2H)thione 4. Thieno[2,3-c]- pyridazines 5a-e were achieved by cycloalkylation of compound 4 with halocompounds in methanol under reflux and in the presence of sodium methoxide. Also, refluxing of compound 4 with N-substituted chloroacetamide in the presence of potassium carbonate afforded thienopyridazines 6a-e. Cyclization of compound 6 with some electrophilic reagents as carbon disulfide and triethyl orthoformate furnished the novel pyrimido[4',5':4,5]thieno[2,3-c]pyridazines 12 and 13a-c, respectively. Diazotisation of compound 6 with sodium nitrite in acetic acid produced the pyridazino[4',3':4,5]thieno[3,2-d][1,2,3]triazines 14a-c. Ternary condensation of compound 1, aromatic aldehydes and malononitrile in ethanol containing piperidine under reflux afforded the novel phthalazines 16a-c. Compound 3 was subjected to some nucleophilic substitution reactions with amines and sodium azide and formed the aminopyridazines 17a, b and tetrazolo[1,5-b]-pyridazine 19, respectively. The structures of the synthesized compounds were established by elemental and spectral analyses.
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Wear properties of ECAP-processed ultrafine grained Al-Cu alloys
Abd El Aal, M.I.,El Mahallawy, N.,Shehata, F.A.,Abd El Hameed, M.,Yoon, E.Y.,Kim, H.S. Elsevier Sequoia 2010 Materials science & engineering. properties, micro Vol.527 No.16
The wear properties of equal channel angular pressing (ECAP) Al-2, 3 and 5%Cu alloys under dry sliding conditions using different sliding distances and loads were investigated by pin-on-disc dry sliding wear tests. The wear mass loss decreased remarkably as the number of ECAP passes and Cu content increased, being affected more by the sliding distance than by the applied load under the experimental conditions. The wear mechanism was observed to be adhesive and delamination initially, and an abrasive mechanism also appeared as the sliding distance increased. The analysis of the wear surface indicates a transfer of Fe from the rotating disc to the Al-Cu alloy pin with increases in the sliding distance, the applied load, the number of passes and the copper content.
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Ultrasonic relaxation in Zinc–Borate glasses
G.E. El-Falaky,M.S. Gaafar,N.S. Abd El-Aal 한국물리학회 2012 Current Applied Physics Vol.12 No.2
Borate glasses in the system (1 - x) [29Na2O - 4Al2O3 - 67B2O3] - x ZnO with (x ¼ 0, 5, 10, 15, 20, 25, 30,and 35 mol%), have been prepared by the melt quenching technique. The longitudinal ultrasonic attenuation of the prepared sample has been measured using the pulse echo technique at ultrasonic frequencies 2, 4, 6 and 8 MHz in the temperature range between 160 and 300 K. The results showed welldefined peak whose position shifts toward higher temperature with increasing frequency. The mean activation energy is strongly composition sensitive. The position and overall shape of the loss peaks in dependence on composition were analyzed in terms of an assumed loss of standard linear solid type with low dispersion, and a broad distribution of Arrhenius-type relaxation with temperature independent relaxation strength. The dependence of ultrasonic attenuation on temperature has been interpreted in terms of a thermally activated relaxation process which arises when ultrasonic waves disturb the equilibrium of an atom moving in a double-well potential in the glass network. The dependence of activation energy on composition suggests that the structure of these glasses changes at 15 mol% ZnO concentration.
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