Tổng hợp tài liệu Khoa Học Tự Nhiên tham khảo cho học sinh, sinh viên.
Two new phenothiazine derivatives, PDA and PyP, have been successfully synthesized via Buchwald-Hartwig C-N coupling amination with the present of catalytic palladium. The chemical structures of these products were analyzed by 1H NMR spectra while light absorption properties were characterized via UV – Vis spectroscopy in a series of different c...
7 trang | Chia sẻ: honghp95 | Ngày: 02/12/2020 | Lượt xem: 494 | Lượt tải: 0
Three cholestane-type steroids, (22E)-cholesta-5,22-dien-3β-ol-7-one (1), trans-liagosterol (2), and guggulsterol-II (3), were isolated and structurally elucidated from methanol extract of the Vietnamese octocoral Verrucella corona. Among them, compound 2 showed significant cytotoxicity against eight human cancer cell lines as HepG2, HL-60, KB, ...
7 trang | Chia sẻ: honghp95 | Ngày: 02/12/2020 | Lượt xem: 432 | Lượt tải: 0
The cell-protective effects of crude ethanol extract and some fractioned extracts as well as some isolated compounds from Euphorbia hirta L. collected in the Mekong Delta on ER stressinduced cell death in mouse β-cell lines were investigated. The results of this study revealed that methanol extract and quercitrin isolated from Euphorbia hirta L. ...
8 trang | Chia sẻ: honghp95 | Ngày: 02/12/2020 | Lượt xem: 416 | Lượt tải: 0
The 1H NMR spectrum of compound 4 has signals for the trans-double bond with big coupling constant (H-2, H-3, J = 16.5 Hz) and three aromatic protons, together with one methyl group. The methyl group has HMBC correlation with C-1 (199.1 ppm), indicating the presence of CH3CO- partital structure. This moiety is connected with the double bond C2-3...
6 trang | Chia sẻ: honghp95 | Ngày: 02/12/2020 | Lượt xem: 437 | Lượt tải: 0
The SEM and EDS results confirmed the presence of CNTs in the Ni-CNTs electrodeposition coating. The fine and uniform grain size as well as the presence of CNTs in the electrodeposition coating improved the mechanical properties of the Ni-CNTs coating compared to the Ni coating. The measurement results showed that the hardness and adhesion of th...
8 trang | Chia sẻ: honghp95 | Ngày: 02/12/2020 | Lượt xem: 472 | Lượt tải: 0
The alginate/chitosan/polycaprolactone/lovastatin (AG/CS/PCL/LS) composite films were prepared by solution method. The presence of PCL as a compatibilizer contributes to enhance the compatibility, interaction and dispersion of CS, AG and LS in the composite films, therefore, LS rods are more uniformly dispersed in the AG/CS//LS composite films, ...
9 trang | Chia sẻ: honghp95 | Ngày: 02/12/2020 | Lượt xem: 584 | Lượt tải: 0
The aim of this study was to compare the stability of different waterborne paints based on the acrylic emulsion, TiO2, additives and either in absence of Luconyl or in presence of Luconyl. After 800-hour aging, both of the paint systems showed that there was no significant change in general appearance. The adhesion was stable after aging. Howeve...
11 trang | Chia sẻ: honghp95 | Ngày: 02/12/2020 | Lượt xem: 527 | Lượt tải: 0
In the Cho Dien deposit, strong weathering process makes the upper part of ore bodies completely oxidized. Primary ore minerals are mainly sphalerite, pyrite, galena which are replaced by secondary ore minerals such as hemimorphite (calamine), smithsonite, goethite, anglesite and cerusite. Difference in geochemical behavior of lead (Pb) and z...
12 trang | Chia sẻ: honghp95 | Ngày: 02/12/2020 | Lượt xem: 516 | Lượt tải: 0
Compound 5 was obtained as white powder. The EI-MS of 5 showed a pseudomolecular ion peak at m/z 454 [M]+, combination with 1H- and 13C-NMR spectral data allowed to propose the molecular formula of C30H46O3. In its 1H-NMR spectrum, there were proton signals characteristic of three olefinic protons [ H 5.47 (1H, d, H-7); 6.91 (1H, t, H-24) and 5....
7 trang | Chia sẻ: honghp95 | Ngày: 02/12/2020 | Lượt xem: 522 | Lượt tải: 0
LiFePO4 and nickel doped samples were successfully synthesized using solvothermal technique. The nickel impact on LFP structure clearly exhibited by the decrease of volume and lattice cell parameter as well as suppression of some vibration bands (translation and internal modes). The capacity and voltage of doped samples enhanced significantly du...
8 trang | Chia sẻ: honghp95 | Ngày: 02/12/2020 | Lượt xem: 884 | Lượt tải: 0
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