排序方式: 共有57条查询结果,搜索用时 296 毫秒
11.
Rajendran Suresh Babu Pandurangan Prabhu Sangilimuthu Sriman Narayanan 《Journal of Solid State Electrochemistry》2016,20(6):1575-1583
In this paper, a facile immobilization of copper hexacyanoferrate nanoparticles (CuHCFNP) on a paraffin wax-impregnated graphite electrode (PIGE) was carried out using the room-temperature ionic liquid (RTIL) 1-ethyl-3-methylimidazolium tetrafluoroborate (EMIMBF4) as an ionic binder. The characteristics of the CuHCFNP/EMIMBF4 gel-modified electrode were investigated by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) techniques, and the modified electrode morphology was also characterized using field emission scanning electron microscopy (FESEM). The electrocatalytic behavior of butylated hydroxyl anisole (BHA) at the modified electrode has been investigated in 0.1 M KNO3 in static and dynamic conditions. Under the optimum conditions, the oxidation peak current was proportional to the BHA concentration in the range from 1.5 to 1000 μM with a detection limit of 0.5 μM (S/N = 3). The proposed method was applied to determine BHA content in real samples with satisfactory results. 相似文献
12.
Jeyaraman Vikramathithan Sambandam Ravikumar Pandurangan Muthuraman Gali Nirmalkumar Sivalingam Shayamala Kotteazeth Srikumar 《Cellulose (London, England)》2012,19(4):1373-1383
Thermostable xylanase isoforms T70 and T90 were purified and characterized from the xerophytic Opuntia vulgaris plant species. The enzyme was purified to homogeneity employing three consecutive steps. The purified T70 and T90 isoforms yielded a final specific activity 134.0 and 150.8 U mg?1 protein, respectively. The molecular mass of these isoforms was determined to be 27 kDa. The optimum pH for the T70 and T90 xylanase isoforms was 5.0 and the temperature for optimal activity was 70 and 90 °C, respectively. The Km value of T70 and T90 enzyme isoforms was 3.49, 2.1 mg ml?1, respectively when oat spelt xylan was used as a substrate. The T70 had a Vmax of 10.4 μmol min?1 mg?1, and T90 had a Vmax of 8.9 μmol min?1 mg?1, respectively. In the presence of 10 mM Co2+, and Mn2+ the activity of T70 and T90 isoforms increased, where as 90 % inhibition was noted with of the use 10 mM Hg2+, Cd2+, Cu2+, Zn2+ while partial inhibition was observed in the presence of Fe3+, Ni2+, Ca2+and Mg2+. The T70 and T90 isoforms retained nearly 50 % activity in the presence of 2.0 M urea, while use of 40 mM SDS lowered the activity nearly 38–41 %. The substrate specificity of both T70 and T90 isoforms showed maximum activity for oat spelt xylan. Western blot, immunodiffusion, and in vitro inhibition assays confirmed reactivity of the T90 isoform with polyclonal anti-T90 antibody raised in rabbit, as well as cross-reactivity of the antibody with the T70 xylanase isoform. 相似文献
13.
Rhodium(II) acetate catalyzed reactions of various α-diazo ketones, and vinyl ethers afforded γ-ketoaldehydes or 1,4-diketones in a facile manner. In this process, oxycyclopropanes are formed as intermediates, and are subsequently ring opened in the presence of the rhodium(II) acetate catalyst to furnish the corresponding 1,4-dicarbonyl compounds. The scope of this protocol has been demonstrated with the synthesis of a serotonin antagonist. 相似文献
14.
Hypervelocity impact resistance of reinforced carbon-carbon/carbon-foam thermal protection systems 总被引:1,自引:0,他引:1
Common aero vehicles (CAVs) are aerodynamically designed, (from orbit) re-entry, un-powered military vehicles planned to be used for deployment of the desired munitions with increased accuracy and range. In one of the currently considered designs of the CAVs, their outer skin is planned to be constructed from two-ply panels. The outer play is made of a carbon-carbon composite while the inner ply is constructed from a carbon-based foam. In the present work a transient non-linear-dynamics-based analysis is carried out in order to predict the extent of damage and the probability for failure of the carbon-carbon/carbon-foam CAV panels during potential hypervelocity impact of space debris with the outer surface of the CAVs. The results obtained show that the extent of damage scales with the normal component of the momentum associated with the debris particles just before the impact. In addition, it is found that despite its relatively low strength, the carbon-foam can provide a major increase in the resistance of the CAV panels towards penetration of the hypervelocity debris particles. This finding has been linked with an attendant consolidation of the foam, the process that is capable of absorbing a substantial amount of kinetic energy carried by the debris particles. 相似文献
15.
Palani N. S. Kavitha N. S. Venkatesh K. S. Ashok Kumar K. Thirumal V. Pandurangan A. Sekar C. Ilangovan R. 《Journal of Solid State Electrochemistry》2018,22(10):3273-3287
Journal of Solid State Electrochemistry - Graphene sheet/multiwall carbon nanotube (GMC) and its composites with NiO and Ni(OH)2 are synthesized by microwave-assisted technique for the application... 相似文献
16.
Four new macrocyclic dinuclear dibutyltin(IV) dithiocarbamate complexes of the type [Bu2Sn(dtc)]2, where dtc = hexane‐1,6‐diylbis(4‐fluorobenzyldithiocarbamate) anion ( 1 ), hexane‐1,6‐diylbis(4‐chlorobenzyldithiocarbamate) anion ( 2 ), hexane‐1,6‐diylbis(furfuryldithiocarbamate) anion ( 3 ) and hexane‐1,6‐diylbis(pyrrole‐2‐ylmethyldithiocarbamate) anion ( 4 ), have been prepared. The dithiocarbamate ligands efficiently self‐assemble with Bu2Sn(IV) to form bimetallic 26‐membered macrocycles. All the complexes have been characterized using elemental analysis, infrared and NMR (1H and 13C) spectroscopies and X‐ray crystallography. Single‐crystal X‐ray diffraction analysis of all the complexes confirms the formation of the dinuclear metallomacrocycles in which dithiocarbamate ligands are asymmetrically bound to the tin atoms. The coordination sphere around the tin atom in 1 – 4 can be described as a skew trapezoidal bipyramid. The dimensions of the cavity of the macrocycles of 1 – 4 are ca 8.0 × 9.0 Å2. Complexes 1 – 4 were evaluated for their in vitro anticancer activity against MCF‐7 and HL‐60 cells. Complexes 1 and 2 are more active against MCF‐7 and HL‐60. Thermal decomposition of 1 and 4 yielded tin sulfides. They were characterized using powder X‐ray diffraction (PXRD), high‐resolution transmission electron microscopy and UV diffuse reflectance and energy‐dispersive X‐ray spectroscopies. PXRD studies reveal that the as‐prepared tin sulfides are composed of orthorhombic phase of SnS. 相似文献
17.
18.
T. SomanathanN. Gokulakrishnan G. ChandrasekarA. Pandurangan 《Applied Surface Science》2011,257(7):2940-2943
The growth of multiwalled carbon nanotubes (MWNTs) was successfully achieved in the channels of three dimensional (3D) iron loaded mesoporous matrices (KIT-6) by employing catalytic chemical vapour deposition (CCVD) technique. The synthesised MWNTs, which were characterised by SEM, TEM and Raman spectroscopy, consist of thick graphene layers of about 10 nm composed of 29 graphene sheets with inner and outer diameter of ∼17 nm and ∼37 nm, respectively. The Raman spectrum showed the formation of well-graphitised MWNTs with significantly higher IG/ID ratio of 1.47 compared to commercial MWNTs. Comparatively, 2 wt% Fe loaded KIT-6 material produced a better yield of 91%, which is also highest compared with the report of MWNTs synthesis using mesoporous materials reported so far. 相似文献
19.
Mesoporous Si-MCM-41 molecular sieve was synthesized hydrothermally and different wt.% of Sb (1.0, 2.0, 3.0, 5.0, 10.0, 15.0 and 20.0) was loaded on it by wet impregnation method. The Sb/MCM-41 materials were characterized by various physico-chemical techniques such as XRD, TGA and TEM. The TEM image showed a honeycomb structure of the host material. They were used as catalytic templates for the growth of MWCNTs by CVD method with different temperatures at 700, 800, 900 and 1000 °C using acetylene as a carbon precursor. The reaction temperature was optimized for the better formation of MWCNTs and they were purified and then characterized by XRD, SEM, HR-TEM and Raman spectroscopy techniques. The formation of MWCNTs with diameter in the range of 4−6 nm was observed from HR-TEM. The good thermal stability and high productivity of catalyst observed in this study revealed that the 2 wt.% Sb loaded MCM-41 could be a promising support for the catalytic synthesis of MWCNTs at 800 °C by CVD method. 相似文献
20.
The reaction of benzaldehyde with aliphatic glycols was performed over Al-MCM-41 with various Si/Al ratios. The effects of various parameters like temperature, mole ratio, reaction time and catalyst amount on the formation of acetals were optimized. The mesoporous Al-MCM-41 (Si/Al ratio 36, 57, 81 and 108) were synthesized by hydrothermal method. The synthesized catalysts were characterized by X-ray diffraction (XRD), nitrogen adsorption–desorption isotherm (BET), thermo gravimetric-differential thermal analysis (TGA-DTA) and TEM techniques. The acidity of the catalysts was measured by pyridine adsorption followed by FT-IR analysis. TEM analysis showed that the honeycomb-like regular arrangement of hexagonal pores on the molecular sieves. The highly hydrophobic Al-MCM-41 (108) showed higher activity than the other Si/Al ratios. The activity of the catalysts showed the following order Al-MCM-41 (108) > Al-MCM-41 (81) > Al-MCM-41 (57) > Al-MCM-41 (36). The hydrophobicity and nucleophilicity of the glycols highly influences the conversion of benzaldehyde, it followed the order; hexylene glycol (HG) > propylene glycol (PG) > ethylene glycol (EG). The results showed that mole ratio of 1:3 (aldehyde:glycol) gave higher yield than the other mole ratios. 相似文献