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The potential of solar cells have not been fully tapped due to the lack of energy conversion efficiency. There are three important mechanisms in producing high efficiency cells to harvest solar energy; reduction of light reflectance, enhancement of light trapping in the cell and increment of light absorption. The current work represent studies conducted in surface modification of single-crystalline silicon solar cells using wet chemical etching techniques. Two etching types are applied; alkaline etching (KOH:IPA:DI) and acidic etching (HF:HNO3:DI). The alkaline solution resulted in anisotropic profile that leads to the formation of inverted pyramids. While acidic solution formed circular craters along the front surface of silicon wafer. This surface modification will leads to the reduction of light reflectance via texturizing the surface and thereby increases the short circuit current and conversion rate of the solar cells. 相似文献
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Permanaa D Abas F Maulidiani Shaari K Stanslas J Ali AM Lajis NH 《Zeitschrift für Naturforschung. C, Journal of biosciences》2005,60(7-8):523-526
A new prenylated depsidone, atrovirisidone B (2), together with naringenin (3) and 3,8"-binaringenin (4) were isolated from the roots of Garcinia atroviridis. Their structures were determined on the basis of spectral data interpretation. Compound 2 showed cytotoxic activity against human breast (MCF-7), human prostate (DU-145) and human lung (H-460) cancer cells. 相似文献
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Isolated cotyledons of Phaseolus vulgaris L. cv. Canadian Wonder accumulated 14C2H4 (0.7–1 l l-1) from air to give partition coefficients of 1 to 4, which greatly exceeded the value obtained with steam killed cotyledons (0.05) and with water (0.11). After 14C2H4 treatment, 98% of the 14C in the tissue remained as 14C2H4. The labelled ethylene accumulated by cotyledons was released only slowly (1–10% h-1) either in an air stream or into toluene. Heating to 60°C for 2 h, but not freezing and thawing, caused the immediate release of 14C2H4 from the tissue. Propylene and vinyl chloride competitively inhibited the accumulation of 14C2H4.Cotyledons emanated endogenous ethylene at a very low rate but after heating (although not freezing and thawing) 13 nl of ethylene per g fresh mass were released within minutes. It was concluded that french bean cotyledons hold ethylene in a compartmented form in sufficient amount to account for at least 200 h of emanation.Abbreviation PPO
diphenyloxazole 相似文献
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Anthraquinones from Hedyotis capitellata 总被引:1,自引:0,他引:1
Four new furanoanthraquinones, 2-hydroxymethyl-3,4-[2'-(1-hydroxy-1-methylethyl)-dihydrofurano]-8-hydroxyanthraquinone, 2-hydroxymethyl-3,4-[1'-hydroxy-2'-(1-hydroxy-1-methylethyl)-dihydrofurano]-8-hydroxyanthraquinone, 2-hydroxymethyl-3,4-[2'-1-hydroxy-1-methylethyl)-dihydrofurano]anthraquinone and 2-methyl-3,4-[2'-(1-hydroxy-1-methylethyl)-dihydrofurano] anthraquinone or capitellataquinone A-D and four known anthraquinones, rubiadin, anthragallol 2-methyl ether, alizarin 1-methyl ether and digiferruginol, together with scopoletin were isolated from the stems of Hedyotis capitellata Wall (Rubiaceae). Lucidin-3-O-beta-glucoside was isolated from the roots of the plant. Characterization of the new compounds was carried out by extensive NMR studies using FGCOSY, FGHMQC, FGHMBC and DEPT-135 in addition to other spectroscopic methods. 相似文献
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Nura Abdullahi Elias Saion Abdul Halim Shaari Naif Mohammed Al-Hada Aysar Keiteb 《PloS one》2015,10(5)
MWCNTs/TiO2 nanocomposite was prepared by oxidising MWCNT in H2SO4/HNO3 then decorating it with TiO2-p25 nanopowder. The composites were characterised using XRD, TEM, FT-IR PL and UV−vis spectroscopy. The TEM images have shown TiO2 nanoparticles immobilised onto the sidewalls of the MWCNTs. The UV-vis spectrum confirms that the nanocomposites can significantly absorb more light in the visible regions compared with the commercial TiO2 (P25). The catalytic activity of these nanocomposites was determined by photooxidation of MB aqueous solution in the presence of visible light. The MWCNTs/TiO2 (1:3) mass ratio showed maximum degradation efficiency. However, its activity was more favourable in alkaline and a neutral pH than an acidic medium. 相似文献
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Naif Mohammed Al-Hada Elias B. Saion Abdul Halim Shaari Mazliana A. Kamarudin Moayad Husein Flaifel Sahrim Hj Ahmad Salahudeen A. Gene 《PloS one》2014,9(8)
A facile thermal-treatment route was successfully used to synthesize ZnO nanosheets. Morphological, structural, and optical properties of obtained nanoparticles at different calcination temperatures were studied using various techniques. The FTIR, XRD, EDX, SEM and TEM images confirmed the formation of ZnO nanosheets through calcination in the temperature between 500 to 650°C. The SEM images showed a morphological structure of ZnO nanosheets, which inclined to crumble at higher calcination temperatures. The XRD and FTIR spectra revealed that the samples were amorphous at 30°C but transformed into a crystalline structure during calcination process. The average particle size and degree of crystallinity increased with increasing calcination temperature. The estimated average particle sizes from TEM images were about 23 and 38 nm for the lowest and highest calcination temperature i.e. 500 and 650°C, respectively. The optical properties were determined by UV–Vis reflection spectrophotometer and showed a decrease in the band gap with increasing calcination temperature. 相似文献
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Khairana Husain Siti Mariam Zakaria Nordin H. Lajis Khozirah Shaari Intan Safinar Ismail Daud A. Israf Christian Paetz 《Phytochemistry letters》2012,5(4):788-792
A novel sesquiterpene, nordine (or 2,2,9-trimethyl-5-methylene-12-oxa-bicyclo[6.3.1]dodecane-4,9-diol) (1) and two new copyrine alkaloids of eupolauridine skeleton, viz., 4,11-dimethoxyeupolauridine (2) and 2-methoxy-3-hydroxyeupolauridine (3), along with five alkaloidal (4–8) and nine non-alkaloidal compounds (9–17), have been isolated from the bark and roots of Anaxagorea javanica Blume. The structures of the new constituents were deduced by NMR spectral data. Compounds 6 and 7 displayed moderate inhibition of NO production with IC50 values of 18.2 and 32.3 μg/ml respectively. 相似文献
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Abas F Hui LS Ahmad S Stanslas J Israf DA Shaari K Lajis NH 《Zeitschrift für Naturforschung. C, Journal of biosciences》2006,61(9-10):625-631
Nine derivatives of three natural diarylheptanoids, curcumin, demethoxycurcumin and bisdemethoxycurcumin, were prepared. Their antioxidant, free radical scavenging, nitric oxide (NO) inhibitory and cytotoxic activities were evaluated and compared with those of the respective natural compounds. Curcumin (1), demethoxycurcumin (2), demethyldemethoxy-curcumin (C3), diacetyldemethoxycurcumin (AC2) and triacetyldemethylcurcumin (AC5) exhibited higher antioxidant activity than quercetin while products from demethylation of 1 and 2 exhibited higher free radical scavenging activity. Compounds AC2 and AC5 were found to be most active in inhibiting breast cancer cells (MCF-7) proliferation with IC50 values of 6.7 and 3.6 microM, respectively. The activity of AC2 is almost doubled and of AC5 almost tripled as compared to curcumin. Their selectivity towards different cell lines is also more noticeable. Compounds AC2 and AC5 also showed increased activity against a human prostate cancer cell line (DU-145) and non-small lung cancer cell line (NCI-H460) with IC50 values of 20.4, 16.3 and 18.3, 10.7 microM, respectively. 相似文献