Si11Mn0/+ cluster is endohedral or exohedral: a proof by DFT calculation - Cao Thi Thanh HuongThe B3P86/6-311+G(d) quantum chemical calculation method has been employed for searching the stable geometrical structures of Si11, Si11Mn+, and Si11Mn0 clusters. While for the lowest energy structure of Si11Mn+ cationic cluster, the Mn dopant locates outer the Si11 cage forming the exohedral isomer, the endohedral isomers which have relative...
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Sterols from stems of Momordica cochinchinesis (Lour.) Spreng - Nguyen Thi MaiThe molecular formula of 3 was suggested as C29H48O (M = 412) by the ESI-MS ion peak at m/z 411 [M-H]- and NMR data. The 1H-NMR spectrum of 3 showed signals for 6 methyl groups at δH 0.55 (3H, s), 0.79 (3H, d, J = 6.5 Hz), 0.80 (3H, s), 0.81 (3H, t, J = 7.5 Hz), 0.85 (3H, d, J = 6.5 Hz) and 1.03 (3H, d, J = 6.5 Hz). Besides, the presence of ...
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One-Pot, selective synthesis of orthorhombic and rhombohedral NaNbO3 by hydrothermal method - Nguyen Duc VanBy simply tuning the (K++Na+)/Nb5+ molar ratio from 9.0 to 12.0, the pure rhombohedral and orthorhombic NaNbO3 microcrystals were selectively synthesized by an additive-free hydrothermal procedure using commercialized Nb2O5, NaOH, KOH as starting materials at 180 and 200 oC, respectively, for 24 h. The results showed that the phase compositi...
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Experimental method to determine the pore structure and pore size distribution of gamma alumina (-Al2O3) material - Vu Hong ThaiTo conclude, in this work, the experiments to determine the pore size structure and the pore size distribution of γ-Al2O3 particles are presented. By using the environmental scanning electron microscopy (ESEM), it is observed that the samples have a bimodal pore size distribution with large pores (approximately 1.5 m) and small pores (appro...
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Isolation and identification of phenolic compounds from the leaf extract of Cassia alata L - Pham Quang DuongIn our study, the MeOH leaf extract of C. alata exhibited a significant antibacterial activity against human pathogenic bacteria strains S. aureus and B. cereus with the same MIC value of 63 µg/ml (data not shown). The phytochemical constituents in the leaves of C. alata were also determined to be as methyl 2,4,6-trihydroxybenzoat (1), kaempf...
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Electrochemical deposition of NiCu alloys in citrate solutions - Uong Van VyObserve polarization curves can see Ni2+ ions starting discharge at electrode potential from -0.8 V/SCE, the electrode potential more negative then cathode current density higher. The slope of the polarization curve increases with increasing of Ni2+ ion concentration, polarization curves in solution Ni2+ 0.3 M began appearing critical current...
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A thoroughly theoretical investigation into complexes formed by interaction of dimethyl sulfoxide with two water molecules - Pham Ngoc KhanhInteraction of dimethyl sulfoxide with two water molecules induces three quite stable complexes with interaction energies between -30.3 and -52.7 kJ.mol- 1 at MP2/6-311++G(2d,2p) level. The stability of obtained complexes is mainly determined by the O−H∙∙∙O hydrogen bonds along with the complementary role of O−H∙∙∙S and C−H∙∙∙O hydrogen bond...
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Some triterpenoids and steroids from Bruguiera cylindrica leaves collected from Can Gio mangrove forest - Nguyen Thi Huong QueCompound 4 was isolated as a white amorphous powder. Based on the HR-ESI-MS spectrum, the molecular formula of 4 was determined as C27H44O with a pseudomolecular ion peak at m/z 385.3448 [M+H]+ (calc. for C27H44O+H, 385.3470). The 1H-NMR spectrum of 4 displayed a singlet at δ 5.72 (1H, s, H-4), three methyl doublets at δ 0.91 (3H, d, J = 6.5...
4 trang | Chia sẻ: honghp95 | Ngày: 01/12/2020 | Lượt xem: 795 | Lượt tải: 0![Structure and chemical bond of carbodiylide complexes [W(CO)5{C(ECp*)2}] (E = B to Tl): DFT calculations - Nguyen Thi Ai Nhung](https://s2.tai-lieu.com/pwz9k16xr4jr01yq7rzg033izykdsbez/thumb/2020/12/03/structure-and-chemical-bond-of-carbodiylide-complexes-wco5ce_JyceSqUhLG.jpg)
Structure and chemical bond of carbodiylide complexes [W(CO)5{C(ECp*)2}] (E = B to Tl): DFT calculations - Nguyen Thi Ai NhungThe calculated structures of the W5-C1E complexes show that ligands C1E are bonded in an arrangement that is tilted with respect to the metal fragment W(CO)5. The theoretical calculation of BDEs suggests that the bond strength of complexes increases from the boron complex W5-C1B to the strongest bonded thallium adduct W5-C1Tl. Analysis of th...
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Effect of fly ash on mechanical properties and morphology of plasterboard based on recycled poly(ethylene terephthalate)After immersing in 30 % HCl solution, plasterboard with 150-175 phr fly ash loading indicated the lowest changed values (0.1-0.2 %) whereas plasterboard with 100 and 200 phr fly ash loading caused a more significant change in values (0.5-0.6 %). Chemical resistance such as acid and base resistance have a key role in applications. The presenc...
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