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21.
A new series of liquid crystalline main chain copolyesters were prepared, having ferrocene in the mesogenic segment and a methyl phosphate group along with a methylene spacer. The even numbered methylene groups were varied from two to ten. Liquid crystalline behaviour was investigated on a hot stage optical polarized microscope. Thermal properties of the polymers were analysed by TGA and DSC, revealing that the polymers yield high char products, probably caused by the formation of phosphorus and iron oxides. The glass transition (Tg) temperatures of the polymers were found to be fairly low, the result of the incorporation of bulky phosphorus and ferrocene moieties in the chain. The phase behaviour was analysed and correlated with the structure of the polymers. The liquid crystalline textures of the polymers became more transparent with increasing spacer length. Energy minimized structures for the polymer repeating units reveal that both the ferrocene and phosphorus moieties produce more molecular entanglement, thus reducing the Tg and Tm of the polymers. 相似文献
22.
Mei‐Hsin Chiu Annamalai Senthil Kumar Sundaram Sornambikai Jyh‐Myng Zen Ying Shih 《Electroanalysis》2010,22(20):2421-2427
A screen‐printed silver strip with a built‐in three‐in‐one electrode (SPAgE) configuration of Ag‐working, Ag‐counter and Ag/AgxO (silver oxides) pseudoreference electrodes has been developed for sensitive and selective electrochemical flow injection analysis (FIA) of aluminum chlorohydrate (ACH) present in antiperspirants, through the free Cl? ion liberated from ACH in aqueous medium, as a redox signal at Ag‐working electrode in pH 6 phosphate buffer solution (PBS). The solution phase and instrumental parameters were systematically optimized. The calibration graph was linear in the window 1–200 ppm concentration of ACH and the lowest detection limit (S/N=3) was 295 ppb with a slope of 0.0989 μA/ppm and regression coefficient of 0.998. Calculated relative standard deviation (RSD) values for the detection of 5 and 50 ppm ACH by this method are 2.21 % and 2.16 %, respectively. Four different antiperspirant deodorants real samples with and without ACH content were successfully analyzed and the detected values obtained were found to be in good agreement with the product labeled values. 相似文献
23.
Chlorella minutissima—A Promising Fuel Alga for Cultivation in Municipal Wastewaters 总被引:1,自引:0,他引:1
Ashish Bhatnagar Monica Bhatnagar Senthil Chinnasamy K. C. Das 《Applied biochemistry and biotechnology》2010,161(1-8):523-536
It is imperative to slash the cost of algal oil to less than $50 bbl?1 for successful algal biofuel production. Use of municipal wastewater for algal cultivation could obviate the need for freshwater and the nutrients—N and P. It would also add CO2 through bacterial activity. Chlorella minutissima Fott et Nova dominated the entire phycoflora year around and through each stage of the wastewater treatment at the oxidation pond system of Wazirabad (Delhi) in India. The ability to grow so profusely in such varied and contrasting situations made this alga unique. Besides pollution tolerance, it grew heterotrophically in dark under acidic conditions and as a mixotroph in presence of light over a range of organic C substrates. It could utilize both ammoniacal and nitrate nitrogen, survived anaerobicity, 5% NaCl and ?10 bar of osmotic stress. C. minutissima grew at pH 4–11 and raised the pH set initially by 1 to 3 units in 7.5 h. It showed gigantism and largely kept afloat in presence of utilizable organic carbon, while flocculated in mineral medium and on aging. The alga also possessed potential for biofuel production. The studied parameters indicate why C. minutissima was a potential biomass builder in municipal sewage and could be used to determine which other alga(e) may serve the purpose. 相似文献
24.
P. Senthil Kumar V. SathyaSelvaBala K. Ramakrishnan P. Vijayalakshmi S. Sivanesan 《Russian Chemical Bulletin》2010,59(10):1859-1864
The feasibility of using granulated activated carbon for adsorption removal of copper from aqueous solution was studied. The
influence of pH, amount of the adsorbent, contact time, and copper concentration on adsorption of copper was investigated.
The single-component equilibrium data on copper adsorption were analyzed using the Langmuir, Freundlich, Redlich—Peterson,
Temkin, and Toth adsorption isotherms. The adsorption process was followed by two simplified kinetic models including pseudo-first-
and pseudo-second-order equations. Kinetic parameters, rate constants, equilibrium sorption capacities, and the corresponding
correlation coefficients were calculated and examined for each kinetic model. It was shown that copper adsorption can be described
by the pseudo-second-order equation. 相似文献
25.
T. Badapanda V. Senthil S.K. Rout L.S. Cavalcante A.Z. Simões T.P. Sinha S. Panigrahi M.M. de Jesus E. Longo J.A. Varela 《Current Applied Physics》2011,11(6):1282-1293
In this work, we report the Rietveld refinement, microstructure, conductivity and impedance properties of Ba[Zr0.25Ti0.75]O3 ceramic synthesized by solid state reaction. This ceramic was characterized by X-ray diffraction, Rietveld refinement, scanning electron microscopy and energy dispersive X-ray spectrometry. Impedance spectroscopy analyses reveals a non-Debye relaxation phenomenon being its relaxation frequency moving toward to positive side with increase of temperature. A significant shift in impedance loss peaks toward higher frequency side indicates conduction in material and favoring the long range motion of mobile charge carriers. The frequency dependent ac conductivity at different temperatures indicates that the conduction process is thermally activated. The variation of dc conductivity exhibited a negative temperature coefficient of resistance behavior. The ac conductivity data are used to evaluate the density of states at Fermi level and activation energy of this ceramic. The dc electrical and thermal conductivities of grain and grain boundary have been discussed. 相似文献
26.
27.
We study theoretically the destruction of spin nematic order due to quantum fluctuations in quasi-one-dimensional spin-1 magnets. If the nematic ordering is disordered by condensing disclinations, then quantum Berry phase effects induce dimerization in the resulting paramagnet. We develop a theory for a Landau-forbidden second order transition between the spin nematic and dimerized states found in recent numerical calculations. Numerical tests of the theory are suggested. 相似文献
28.
Gopal Senthil Kumar Matthias Zeller Michael A. Frasso Karnam Jayarampillai Rajendra Prasad 《Journal of heterocyclic chemistry》2015,52(3):926-930
An efficient and economical method has been developed for the synthesis of pyrano[3,2‐h]quinolines via an indium trichloride‐catalyzed one‐pot three‐component reaction of 8‐hydroxyquinoline with aromatic aldehydes and malononitrile/ethyl cyanoacetate under microwave irradiation. 相似文献
29.
S. Sathiyaraj Mahalingam Vanjinathan G. Libni K. Subalakshmi J. Senthil Selvan 《高分子科学杂志,A辑:纯化学与应用化学》2017,54(12):978-985
Hyperbranched poly(aryl-ether-urea)s with phenyl, N,N-dimethylamino ethyl and polyethylene oxide end-groups linked through urethane group – HBPEU-1, HBPEU-2 and HBPEU-3 respectively – were synthesized from an AB2-type blocked isocyanate monomer and characterized by FT-IR, 1H-NMR, SEC-MALLS, TGA and DSC techniques. The molecular weight of the polymers were found to be ranged from 4.9 × 103 ? 1.96 × 104 g/mol. The TGA results showed that the polymers decompose between 175°C – 220°C. In the DSC curves, HBPEU-1 and HBPEU-3 showed Tg at 160°C and 53°C respectively, whereas HBPEU-2 did not showed clear Tg. All the three polymers were converted into polymer electrolytes by doping with LiI/I2. The doped polymers showed remarkably high ionic conductivity, up to 222 – 277 times compared to the un-doped polymers and the highest conductivity was observed with doped HBPEU-2. The TiO2 based dye-sensitized solar cells (DSSCs) were fabricated using the doped polymer electrolytes and their performance was tested; HBPEU-2 showed good performance by yielding energy conversion efficiency (η) of 4.5%. 相似文献
30.
Selvaraj Mohana Roopan F. Nawaz Khan Jong Sung Jin R. Senthil Kumar 《Research on Chemical Intermediates》2011,37(8):919-927
Montmorillonite K10 efficiently catalyzed a one pot–three component cyclocondensation of isatoic anhydride, NH4OAc and aromatic/heteroaromatic aldehydes under ambient conditions to produce the corresponding 2-substituted-2,3-dihydroquinazolin-4(1H)-ones
in good yields. The 2-(2-chloroquinolin-3-yl)-2,3-dihydroquinazolin-4(1H)-ones 3a–d were screened for their antitumor activity against Ehrlich Ascites Carcinoma tumor cells 相似文献