Tổng hợp tài liệu Khoa Học Tự Nhiên tham khảo cho học sinh, sinh viên.
Compound 4 was isolated as white powder. There are three protons of a trisubstituted aromatic ring at 6.98 (1H, d, J = 8.5 Hz), 6.44 (1H, d, J = 2.5 Hz) and 6.60 (1H, dd, J = 3.0, 8.5 Hz); two singlet equivalence protons 7.32 (2H, s); three aromatic methoxy groups at 3.85 (6H, s, 2 x CH3) and 3.79 (3H, s); and an anomeric of a β-oriented sugar m...
7 trang | Chia sẻ: honghp95 | Ngày: 01/12/2020 | Lượt xem: 466 | Lượt tải: 0
My An mineral water was suitable for the growth of Spirulina platensis after removing H2S. Productivity of Spirulina platensis cultivated in My An mineral water was about 10 g/m2.day. Spirulina platensis biomass had good quality with high amount of crude protein and fatty acids, reaching 68.32 % and 7.32 %, respectively. In addition, the amount ...
9 trang | Chia sẻ: honghp95 | Ngày: 01/12/2020 | Lượt xem: 556 | Lượt tải: 0
Silver nanoparticles are suitable for in vitro Chrysanthemum growth in various culture systems: in vitro solid medium, in vitro liquid medium and microponic system are 1.5; 1.5; 5 ppm, respectively. Different culture systems have different SNPs absorbability which directly proportional to the culture time and inversely proportional to the SNPs c...
12 trang | Chia sẻ: honghp95 | Ngày: 01/12/2020 | Lượt xem: 442 | Lượt tải: 0
Geopolymers was successfully synthesized from RM and RHA under the most appropriate conditions that were: (i) initial material compositions were RM, RHA and NaOH with SiO2/Al2O3 molar ratio of 4 and Na2O/Al2O3 molar ratio of 2.0; (ii) curing temperature of 100oC; (iii) curing time of 24 hours. The physico-mechanical properties including compress...
14 trang | Chia sẻ: honghp95 | Ngày: 01/12/2020 | Lượt xem: 484 | Lượt tải: 0
The study indicated several properties of Nam Son landfill leachate, COD, NH4+ and pH in particular with the concentration in the range of approximately 6247 ± 295, 1270 ± 38 mg/l and 8 respectively. With the increase in current (1 to 4 A), the COD removal efficiencies increased from approximately 50 to 78 % (pH = 8 and operating time = 40 min)....
8 trang | Chia sẻ: honghp95 | Ngày: 01/12/2020 | Lượt xem: 565 | Lượt tải: 0
The modified acacia celluloses from acacia pulp in Vietnam have some different characteristics from the Canadian softwood cellulose, the Indonesian hardwood cellulose and the initial acacia pulp. As the initial acacia pulp, CND and INDO, the AH-7.5 sample is a cellulose I, and the AH-15 sample is a cellulose II. The cellulose I of modified acaci...
9 trang | Chia sẻ: honghp95 | Ngày: 01/12/2020 | Lượt xem: 631 | Lượt tải: 0
In this paper, a real-time interpolation method is presented for parametric NURBS curves. The interpolation algorithm is based on the second order Taylor’s expansion. This method canA method of real-time NURBS interpolation with confined chord error for CNC systems 657 maintain a small feedrate fluctuation, but the chord error can be large at po...
8 trang | Chia sẻ: honghp95 | Ngày: 01/12/2020 | Lượt xem: 550 | Lượt tải: 0
The proposed framework integrates major points of the flipping coin (vulnerability and resilience are normalized as stress and resources, and they are two sides of the same coin) and separation concepts (vulnerability and resilience both can generate positive and/or negative outcomes) to address the dynamic interactions between ecological vulner...
17 trang | Chia sẻ: honghp95 | Ngày: 01/12/2020 | Lượt xem: 582 | Lượt tải: 0
By the method of fabricating quantum dots at 260 oC in 10 minutes, alloyed CdTeSe QDs have been formed with good crystallization and zinc-blende single phase. Raman spectra results were completely in sync with XRD, therefore Raman spectra could be used as an effective tool to estimate the Se and Te compositions available in CdTeSe QDs. Studies o...
11 trang | Chia sẻ: honghp95 | Ngày: 01/12/2020 | Lượt xem: 525 | Lượt tải: 0
Hydroxyapatite/functionalized carbon nanotubes (HAp/fCNTs) coatings were synthesized successfully on the surface of 316L SS substrate by electrodeposition technique. The presence of fCNTs in the HAp/fCNTs nanocomposite decrease the solubility and improve the mechanical properties of the material. In our next studies, we will continue to investig...
10 trang | Chia sẻ: honghp95 | Ngày: 01/12/2020 | Lượt xem: 503 | Lượt tải: 0
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