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41.
The composition and antioxidant activity of the essential oil obtained through hydrodistillation of pimento berry [Pimenta dioica (L.) Merr] samples, namely P1 and P2, sourced from Jamaica, were studied. The chemical composition was analysed by GC and GC-MS methods. The antioxidant activities of the oils were evaluated in terms of their free-radical-scavenging activity against 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2'-azinobis (3-ethylbenzothiazoline-6-sulphonic acid) diammonium salt (ABTS) radical cation and superoxide anion (?[image omitted]). Total phenolic content, total reducing power and metal-chelating capacity of the oils were also estimated. Forty-five constituents were identified. The major compound identified was eugenol (74.71%, 73.35%), followed by methyl eugenol (4.08%, 9.54%) and caryophyllene (4.90%, 3.30%). The antioxidant assays showed that the oils possess very high radical scavenging activities (DPPH IC(50) 4.82 ± 0.08, 5.14 ± 0.11 μg mL(-1), ABTS IC(50) 2.27 ± 0.16, 2.94 ± 0.03 μg mL(-1), superoxide IC(50) 17.78 ± 1.31, 20.65 ± 0.82 μg mL(-1)). The metal chelating capacities (IC(50) 83.62 ± 2.10, 101.77 ± 1.01 μg mL(-1)) and reducing power were also very high. The results show that the essential oils possess significant antioxidant activity which is comparable to that of pure eugenol. Therefore the oil can be utilised as a natural antioxidant which gives good flavour as well as health benefits. 相似文献
42.
Sasidharan Sankar Krishna Gopakumar Warrier 《Journal of Sol-Gel Science and Technology》2011,58(1):195-200
Aqueous sol–gel technique is reported for synthesizing nanosize, rod shaped lanthanum phosphate particles starting from lanthanum
chloride, which is suitable for variety of applications such as machinable ceramics, thermal barrier coatings and luminescent
materials. The phosphate particles are having rod like morphology having an overall size in the range 25–100 nm and with an
average aspect ratio 4. The morphology is retained even after calcination at 800 °C. The average crystallite size for the
as prepared particles was calculated to be 8 nm using Scherrer equation applied on X-ray diffraction (XRD) data. The particles
obtained were characterized using photon correlation spectroscopy (PCS), FT-IR spectroscopy, XRD and Electron Microscopy techniques
(TEM and SEM). The phase stability was found using thermo gravimetric analysis. The surface wettability monitored using tensiometer
through dynamic contact angle method indicated that lanthanum phosphate surface possesses considerable hydrophobic character. 相似文献
43.
Nanda Gunawardhana Nikolay Dimov Manickam Sasidharan Gum-Jae Park Hiroyoshi Nakamura Masaki Yoshio 《Electrochemistry communications》2011,13(10):1116-1118
Lithium deposition on graphite anodes is considered as a main reason for failures and safety for lithium ion batteries (LIB). Different amounts of carbon coating on the surface of natural graphite are used in this work to suppress the amount of lithium deposited at − 10 °C. Pulse polarization experiments reveal relative polarization of graphite anodes at various temperatures and show that lithium deposition is accelerated at lowered temperatures. Electrochemical experiments, along with photographs, scanning electron microscopy (SEM) images and ex-situ X-ray diffraction (XRD) data suggest that carbon coating not only suppresses the lithium deposition but also enhances the formation of LiC6 at − 10 °C. The homogeneous potential profile on the graphite surface attained by the carbon coating explains such an improved low temperature performance, as it allows efficient Solid Electrolyte Interface (SEI) film formation, which is a prerequisite for safety LIB. 相似文献
44.
Dr. Quentin Simon Dr. Davide Barreca Dr. Alberto Gasparotto Dr. Chiara Maccato Prof. Eugenio Tondello Dr. Cinzia Sada Dr. Elisabetta Comini Prof. Giorgio Sberveglieri Dr. Manish Banerjee Dr. Ke Xu Prof. Anjana Devi Prof. Roland A. Fischer 《Chemphyschem》2012,13(9):2342-2348
CuO/ZnO nanocomposites were synthesized on Al2O3 substrates by a hybrid plasma‐assisted approach, combining the initial growth of ZnO columnar arrays by plasma‐enhanced chemical vapor deposition (PE‐CVD) and subsequent radio frequency (RF) sputtering of copper, followed by final annealing in air. Chemical, morphological, and structural analyses revealed the formation of high‐purity nanosystems, characterized by a controllable dispersion of CuO particles into ZnO matrices. The high surface‐to‐volume ratio of the obtained materials, along with intimate CuO/ZnO intermixing, resulted in the efficient detection of various oxidizing and reducing gases (such as O3, CH3CH2OH, and H2). The obtained data are critically discussed and interrelated with the chemical and physical properties of the nanocomposites. 相似文献
45.
Arghya Dutta Dr. Mahasweta Nandi Dr. Manickam Sasidharan Prof. Dr. Asim Bhaumik 《Chemphyschem》2012,13(13):3218-3222
Highly ordered 3D‐hexagonal mesoporous silica HMS‐3 and its vinyl‐ and 3‐chloropropyl‐functionalized analogues HMS‐4 and ‐5, respectively, are synthesized under strongly alkaline conditions at 277 K. Tetraethyl orthosilicate, vinyltrimethoxysilane, and 3‐chloropropyltrimethoxysilane are used as silica sources, and cetyltrimethylammonium bromide as the structure‐directing agent. The 3D‐hexagonal pore structures of HMS‐3, 4‐, and ‐5 were confirmed by powder XRD and high‐resolution TEM studies. Brunauer–Emmett–Teller surface areas of these materials are 1353, 1211, and 603 m2 g?1 for HMS‐3, ‐4, and ‐5, respectively. Among these materials, vinyl‐functionalized mesoporous material HMS‐4 adsorbs the highest CO2 (5.5 mmol g?1, 24.3 wt %) under 3 bar pressure at 273 K. The 3D‐hexagonal pore openings, very high surface area, and cagelike mesopores as well as organic functionalization could be responsible for very high CO2 uptakes of these materials compared to other related mesoporous silica‐based materials. 相似文献
46.
A scheme for studyingq deformed quasi exactly solvable problem has been applied to the Schrödinger Hulthen problem (l=0). It is found that for the confined Hulthen problem, the confining parameter can be related to the deformation parameterq. 相似文献
47.
Alpana Goel Uma V. Sasidharan Nair Archana Yadav 《Central European Journal of Physics》2014,12(9):693-700
The Variable Moment of Inertia (VMI) model is proposed for the assignment of band head spin of super deformed (SD) rotational bands, which in turn is helpful in the spin prediction of SD bands. The moment of inertia and stiffness parameter (C), were calculated by fitting the proposed transition energies. The calculated transition energies are highly dependent on the prescribed spins. The calculated and observed transition energies agree well when an accurate band head spin (I 0) is assigned. The results are in good agreement with other theoretical results reported in literature. In this paper, we have reported the band head spin value 16 rotational band of super deformed Tl isotopes. 相似文献
48.
It is observed that the additive as well as multiplicative Jordan decompositions hold in alternative loop algebras of finiteRA loops and theRA loops for which the additive Jordan decomposition holds in the integral loop ring are characterized. Multiplicative Jordan
decomposition (MJD) inZL, whereL is a finiteRA loop with cyclic centre is analysed, besides settling MJD for integral loop rings of allRA loops of order ≤32. It is also shown that for any finiteRA loopL,U
(ZL) is an almost splittable Moufang loop.
Research of the second author is supported by CSIR. 相似文献
49.
Lukas Mai Nils Boysen David Zanders Dr. Teresa de los Arcos Dr. Felix Mitschker Dr. Bert Mallick Prof. Dr. Guido Grundmeier Prof. Dr. Peter Awakowicz Prof. Dr. Anjana Devi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(31):7489-7500
New precursor chemistries for the atomic layer deposition (ALD) of aluminium oxide are reported as potential alternatives to the pyrophoric trimethylaluminium (TMA) which is to date a widely used Al precursor. Combining the high reactivity of aluminium alkyls employing the 3-(dimethylamino)propyl (DMP) ligand with thermally stable amide ligands yielded three new heteroleptic, non-pyrophoric compounds [Al(NMe2)2(DMP)] ( 2 ), [Al(NEt2)2(DMP)] ( 3 , BDEADA) and [Al(NiPr2)2(DMP)] ( 4 ), which combine the properties of both ligand systems. The compounds were synthesized and thoroughly chemically characterized, showing the intramolecular stabilization of the DMP ligand as well as only reactive Al−C and Al−N bonds, which are the key factors for the thermal stability accompanied by a sufficient reactivity, both being crucial for ALD precursors. Upon rational variation of the amide alkyl chains, tunable and high evaporation rates accompanied by thermal stability were found, as revealed by thermal evaluation. In addition, a new and promising plasma enhanced (PE)ALD process using BDEADA and oxygen plasma in a wide temperature range from 60 to 220 °C is reported and compared to that of a modified variation of the TMA, namely [AlMe2(DMP)] (DMAD). The resulting Al2O3 layers are of high density, smooth, uniform, and of high purity. The applicability of the Al2O3 films as effective gas barrier layers (GBLs) was successfully demonstrated, considering that coating on polyethylene terephthalate (PET) substrates yielded very good oxygen transmission rates (OTR) with an improvement factor of 86 for a 15 nm film by using DMAD and a factor of 25 for a film thickness of just 5 nm by using BDEDA compared to bare PET substrates. All these film attributes are of the same quality as those obtained for the industrial precursor TMA, rendering the new precursors safe and potential alternatives to TMA. 相似文献
50.