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排序方式: 共有141条查询结果,搜索用时 15 毫秒
61.
The polymerization of methyl methacrylate initiated by a mixed ligand complex. [NN′-ethylenebis(salicylideneiminato)](benzoylacetonato)cobalt(III) has been studied in bulk and in benzene at 70° and 80°. The rate of polymerization is proportional to (concentration of the chelate) and the monomer exponent is close to 1.5. The activation energy and the kinetic and transfer constants are evaluated. A free radical mechanism has been proposed. 相似文献
62.
Sanjay Sarkar Nitika Tiwari Meerambika Behera Sankha Chakrabortty Kavya Jhingran Kali Sanjay Shirsendu Banerjee Suraj K. Tripathy 《印度化学会志》2022,99(5):100447
Dyes are commonly used in coloring clothes; in fertilizers, as anti-freezers, as detergents and so on. The use of such dyes has carcinogenic and genotoxic effects. These dyes require proper removal from the environment. Subsequently, a green and low-cost approach promises to adhere to sustainability of the environment while maximum removal of these toxic dyes. The present study describes removal of methyl violet (MV) dye by adsorption process magnetically separable Fe3O4-coir pith composites. The study was evaluated in batch system taking the optimum conditions as: pH: 7, contact time: 12 h, stirring speed: 200 rpm, concentration of dye: 100 mg/L, adsorbent weight: 3 g/L, temp.: 308 K. The central composite design approach of response surface methodology in design-expert software showed maximum removal efficiency (>98%) for optimal parameters. The experimental equilibrium data fitted reasonably well to Langmuir isotherm model. ANOVA analysis along with Fisher's statistical test was also performed to validate the model. The predicted model was at par with the experimental values with adjusted R2 of 0.9914. A thorough investigation of kinetic ( = 0.99; , thermodynamic, adsorption isotherm and eco-toxicological characteristics were performed for proper evaluations of the properties as well as sustainability of the adsorbent material. The whole research indicated encouraging potential of the developed material for adsorption, reusability and sustainability in applications for industrial scale wastewater treatment. 相似文献
63.
S. K. Patil V. V. Ramakrishna M. S. Sajun R. Thiagarajan 《Journal of Radioanalytical and Nuclear Chemistry》1979,54(1-2):159-169
Synergistic extraction of Th(IV) from perchlorate medium by mixtures of HTTA and TBP was studied. These studies include the
effect of the ionic strength, temperature and the diluents on the extraction. Ionic strength was found to influence the extraction
of Th(TTA)4 and Th(TTA)4·TBP whereas the adduct formation in the organic phase was almost unaffected. Increase of temperature resulted in a decrease
of the extraction of Th(IV). The stability of the adduct was found to decrease in the order, cyclohexane > benzene > chloroform. 相似文献
64.
65.
Thiagarajan G Shirao E Ando K Inoue A Balasubramanian D 《Photochemistry and photobiology》2002,76(3):368-372
We have been able to identify a blue fluorophore from the low-molecular weight soluble fraction of human adult nondiabetic brunescent cataract lenses as xanthurenic acid 8-O-beta-D-glucoside (XA8OG) (excitation = 338 nm and emission = 440 nm). To determine the role of this fluorophore in the lens, we have examined its photophysical and photodynamic properties. We found XA8OG to have a fluorescence quantum yield (phi) of 0.22 and a major emission lifetime of 12 ns. We found it to be a UVA-region sensitizer, capable of efficiently generating singlet oxygen species but little of superoxide. We also demonstrated that XA8OG oxidizes proteins when irradiated with UVA light, causing photodynamic covalent chemical damage to proteins. Its accumulation in the aging human lens (and the attendant decrease of its precursor O-beta-D-glucoside of 3-hydroxykynurenine) can, thus, add to the oxidative burden on the system. XA8OG, thus, appears to be an endogenous chromophore in the lens, which can act as a cataractogenic agent. 相似文献
66.
Suraj Chandra Sharma Rekha Goswami Shrestha Lok Kumar Shrestha Kenji Aramaki 《Colloid and polymer science》2008,286(14-15):1613-1619
Rheological behavior of viscoelastic wormlike micelles in an aqueous system of mixed sodium dodecyl trioxyethylene sulfate (SDES)–monolaurin (ML) is presented. Dilute aqueous solution of SDES has a high fluidity and follows Newtonian liquid-like behavior due to formation of small globular type of micellar structure. Addition of lipophilic nonionic cosurfactant ML to dilute or semidilute solution of SDES decreases the interfacial curvature of the aggregates favoring one dimensional micellar growth, and hence, viscosity increases. After a certain concentration of ML, the elongated micelles get entangled with each other leading to the formation of viscoelastic wormlike micelles. The viscoelastic solution follows Maxwell model of a single stress relaxation mode at low-frequency region. Further addition of ML decreases the viscosity of the solution due to formation of micellar joints in the network structure. The viscosity of the viscoelastic wormlike micelles decreases upon heating, and the system with poor viscoelastic character is observed at higher temperatures. 相似文献
67.
Madhan B Xiao J Thiagarajan G Baum J Brodsky B 《Journal of the American Chemical Society》2008,130(41):13520-13521
NMR spectroscopy is used to investigate the heterotrimeric nature of a collagen model peptide. Two distinct peptide chains (A and B) were synthesized to model a site in heterotrimeric basement membrane type IV collagen. For NMR studies, four amino acids in the B chain were labeled with 15N/13C. Circular dichroism spectroscopy and differential scanning calorimetry thermal stability results on a solution with both A and B peptides (molar ratio 2A:1B) are consistent with the presence of one heterotrimeric triple-helical molecular species. Heteronuclear single quantum coherence experiments on homotrimers of the B peptide show trimer peaks which disappear at temperatures higher than 10 degrees C, while the 2A:1B mixture has trimer peaks with increased stability and altered chemical shifts. The reduction in the number of Leu trimer peaks from three to one and the increased stability of trimer resonances confirm the participation of B chains in an AAB heterotrimer molecule. 相似文献
68.
Suraj P. Narula Sukhjeevan Kaur Surinder K. Sharma David C. Povey 《Journal of chemical crystallography》1992,22(2):139-143
Reaction of 1,4-dimethylpyridinium chlorosulphite with anhydrous copper(II) chloride in an atmosphere of dry nitrogen yields an ionic complex containing discrete [CuCl4]2– anions and 1,4-dimethylpyridinium cations. Electronic (solid and in solution), far infrared and1H NMR spectral data predict a distortedT
d
structure which has been confirmed by X-ray crystallography. The crystal structure was solved by the heavy-atom method and refined by full-matrix least squares toR=0.059 for 1685 observed reflections. The [CuCl4]2– anions exhibit twofold symmetry and there are no unusual interactions with the cations. Bond lengths and angles place it in the select class of complexes with the least flattenedT
d
structure. 相似文献
69.
Kumaraguru Duraimurugan Jayaraman Sivamani Munusamy Sathiyaraj Viruthachalam Thiagarajan Ayyanar Siva 《Journal of fluorescence》2016,26(4):1211-1218
We report the synthesis of trisalkoxy substituted 9, 10-bis styrylanthracene derivatives (C8-ant and C12-ant) by Heck coupling with very good yield and their photophysical properties. Both C8-ant and C12-ant exhibit aggregation induced emission (AIE), mechnoflurochromism and thermochromism. Trisubstituted 9, 10-distyrylanthracene molecules having all the luminescent properties in a single molecule are first of its kind. 相似文献
70.
Rekha?Goswami?ShresthaEmail author Suraj?Chandra?Sharma Kenichi?Sakai Hideki?Sakai Masahiko?Abe 《Colloid and polymer science》2012,290(4):339-348
Formation of wormlike micelles (WLMs) in an aqueous mixture of polyoxyethylene cholesteryl ether (ChEOn; where n = 20 and 30) and polyoxyethylene dodecyl ether (C12EOm; where m = 3 and 4) has been reported; rheological and small angle X-ray scattering (SAXS) measurements have been performed in the
micellar solutions of ChEOn as a function of C12EOm for the structural elucidation. When lipophilic cosurfactant, C12EOm is added to the micellar solutions of ChEOn, it favors the sphere-to-cylinder transition due to the penetration of C12EOm in the palisade layer of ChEOn micelle accompanying an increase in viscosity. When the concentration of C12EOm is increased, entangled network of WLMs is formed. A strong shear thinning has been observed in highly viscous samples indicating
the presence of transient networks. Such samples exhibited viscoelastic behavior and could be described by the Maxwell model
with a single stress relaxation mode. A maximum is observed in zero-shear viscosity-C12EOm plot. With further addition of C12EOm, viscosity declines and ultimately a phase separation occurs with the formation of turbid solution of vesicular dispersion.
This decline has been interpreted in terms of micellar branching induced by an increase in endcap energy, E
c (which is compensated by the formation of branch points, having a mean curvature opposite to that of endcaps). The C12EOm induced one-dimensional micellar growth has been confirmed by SAXS. 相似文献