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371.
Cyclic voltammetry and electrochemical impedance studies of Fe(tmphen) 3 2+ (where tmphen?=?3,4,7,8-tetramethyl-1,10-phenanthroline)-immobilized Nafion?-modified glassy carbon electrode (GC/Nf/Fe(tmphen) 3 2+ ) are carried out in 0.1?M Na2SO4 solution. Nafion–Fe(tmphen) 3 2+ complex exhibits efficient electrocatalytic oxidation of isoniazid. The linear double reciprocal plot of current and concentration of isoniazid shows a Michaelis–Menten-type catalytic process. The catalytic oxidation currents are proportional to the concentration of isoniazid and show a wide linear calibration range for the quantitative determination of isoniazid. Detection limit and sensitivity are found to be 13?μM and 2.5?μA?mM?1, respectively. 相似文献
372.
Sol-gel process has gained tremendous attention in past decades for the preparation of pure and composite material for numerous
applications. Organically modified sol-gel glasses (ormosils) have hybrid properties of rigid inorganic silica matrix and
organic functionalities. Ormosils provide ambient environment for bio-molecules encapsulation and such systems have been used
widely for biosensor applications. Biological elements including enzymes, antibodies, antigens, DNA, whole cells, tissues,
proteins, biologically derived material, and biomimetic materials provide the possibility of biological recognition to the
device and transducer to detect the biological signals with the help of associated electronics and software to amplify these
signals into a readable form for the user. In this review we report on the formation of sol-gel based composite materials
primarily on ormosil along with carbon nano tubes, metal nano particles, mediators, inorganic complexes, polymers, ionomers
and biological materials and cite the electrochemical sensor/biosensor system based on it. 相似文献
373.
Dinesh Kumar Inder Pal Singh Kapoor Gurdip Singh Nidhi Goel Udai Pratap Singh 《Journal of Thermal Analysis and Calorimetry》2012,107(1):325-334
Recent work has described the preparation and characterization of the two complexes [Fe2(C10H8N2)4O(OH2)2](NO3)4 and [Co(C10H8N2)3]2[Co(OH2)6]·7(OH2) (NO3)8 in which both the nitrogen atoms of 2,2′-bipyridine are directly bonded with the metals. Their structures were determined
by single-crystal X-ray diffraction at 296 K. Thermolysis of these complexes has been detailed by the use of TG–DTA and ignition
delay measurements. Kinetics of thermal decomposition has also been established. Model free isoconversional and model fitting
kinetic approaches have been applied to isothermal TG data for the decomposition of these complexes. 相似文献
374.
In this study, the kinetics of glass transitions of Ti50Cu20Ni30 and Fe67Co18B14Si1 metallic glasses are studied using thermal analysis technique, i.e., differential scanning calorimetry, by means of continuous heating of the sample at various heating rates. In the present study, based on the heating rate dependence of glass transition temperature (T g), the activation energy (E) of the glass transition region is determined by two most frequently used approaches, i.e., Moynihan's method and Kissinger's equation. The fragility index, m, is also calculated using T g, which is a measure of glass-forming ability of the given system. The result shows that the fragility index, m, of the given systems is <16. This indicates that the given systems are strong liquids with excellent glass-forming ability. 相似文献
375.
Pratap R. Patnaik 《Reaction Kinetics and Catalysis Letters》2000,71(2):301-306
For -galactosidase production by a recombinant strain of Escherichia coli, fractal dimensions have been computed for two intra-cellular and two extra-cellular variables under three kinds of Guassian noise. The fractal dimensions changed significantly with both fluid mixing and noise, indicating their usefulness as discriminating indexes to optimize mixing intensity and filtering of inflow noise. 相似文献
376.
Metallic glasses have received considerable attention in comparison to normal metallic materials due to their superior physical
and mechanical properties. These systems possess large under cooled region, ∆T (∆T = T
x − T
g where, T
x is crystallization temperature and T
g is glass transition temperature) and hence increased thermal stability against crystallization. Due to this, the study of
their crystallization kinetics is important and interesting. It is interesting because of the fact that, crystallization becomes
multi-step process due to several components present in these systems. In this paper, we report the experimental investigations
of crystallization of Zr52Cu18Ni14Al10Ti6 glassy alloy system, which is among the best non-beryllium containing glasses, using differential scanning calorimetry (DSC).
The crystallization, as expected, consists of multiple steps. Interestingly, the peak heights of these steps vary with heating
rate. At lower heating rates, first peak is most prominent and subsequently diminishes with increase in heating rate with
last peak prominence visible at highest heating rate. Both, iso-kinetic and iso-conversional methods of analysis of kinetics
of crystallization have been used to evaluate the activation energy and Avrami exponents and consistent results are obtained. 相似文献
377.
Tejas Patel Ludmila Abezgauz Dganit Danino Vinod Aswal Pratap Bahadur 《Journal of Dispersion Science and Technology》2013,34(8):1083-1091
Formation and structure of micelles from two amphiphilic polystyrene-block-poly(ethylene oxide) (PS-PEO) diblock copolymers (PS mol.wt. 1000; PEO mol.wt. 3000 and 5000) were examined by surface tension, viscosity, steady state fluorescence, dynamic light scattering (DLS), small angle neutron scattering (SANS), and cryo-transmission electron microscopy (cryo-TEM). The critical micelle concentration (CMC) of the copolymers in aqueous solution was ca. 0.05%; micelle hydrodynamic diameter was 30–35 nm with a narrow size distribution. SANS studies show that the copolymers form ellipsoidal micelles with semi major axis ~23 nm and semi minor axis ~8 nm. No significant change in the structure was found with temperature and presence of salt. The copolymer micelles interaction with the ionic surfactants sodium dodecyl sulphate (SDS) and dodecyltrimethylammonium bromide (DTAB) was also examined by DLS and SANS. 相似文献
378.
Highly Emissive Luminogens Based on Imidazo[1,2‐a]pyridine for Electroluminescent Applications 下载免费PDF全文
Natarajan Nagarajan Gunasekaran Velmurugan Asit Prakash Dr. Nanda Shakti Prof. Dr. Monica Katiyar Prof. Dr. Ponnambalam Venuvanalingam Prof. Dr. Rajalingam Renganathan 《化学:亚洲杂志》2014,9(1):294-304
A search for novel organic luminogens led us to design and synthesize some N‐fused imidazole derivatives based on imidazo[1,2‐a]pyridine as the core and arylamine and imidazole as the peripheral groups. The fluorophores were synthesized through a multicomponent cascade reaction (A3 coupling) of a heterocyclic azine with an aldehyde and alkyne, followed by Suzuki coupling and a multicomponent cyclization reaction. All of the compounds exhibited interesting photophysical responses, especially arylamine‐containing derivatives, which displayed strong positive solvatochromism in the emission spectra that indicated a more polar excited state owing to an efficient charge migration from the donor arylamine to the imidazo[1,2‐a]pyridine acceptor. The quantum yields ranged from 0.2 to 0.7 and depended on the substitution pattern, most notably that based on the donor group at the C2 position. Moreover, the influence of general and specific solvent effects on the photophysical properties of the fluorophores was discussed with four‐parameter Catalán and Kamlet–Taft solvent scales. The excellent thermal, electrochemical, and morphological stability of the compounds was explored by cyclic voltammetry, thermogravimetric analysis, and AFM methods. Furthermore, to understand the structure, bonding, and band gap of the molecules, DFT calculations were performed. The performance of the electroluminescence behavior of the imidazo[1,2‐a]pyridine derivative was investigated by fabricating a multilayer organic light‐emitting diode with a configuration of ITO/NPB (60 nm)/EML (40 nm)/BCP (15 nm)/Alq3 (20 nm)/LiF (0.5 nm)/Al(100 nm) (ITO=indium tin oxide, EML=emissive layer, BCP=2,9‐dimethyl‐4,7‐diphenyl‐1,10‐phenanthroline, Alq3=tris(8‐hydroxyquinolinato)aluminum), which exhibited white emission with a turn‐on voltage of 8 V and a brightness of 22 cd m?2. 相似文献
379.
The phytochemical and biological investigation of Cissampelos pareira leads to the isolation of one new isoquinoline alkaloid (7) along with six known isoquinoline alkaloids, namely, magnoflorine (1), magnocurarine (2), cissamine (3), curine (4), hayatinine (5) and cycleanine (6). Magnoflorine (1) and magnocurarine (2) were isolated for the first time from C. pareira. A new, rapid, simple and sensitive UPLC method was developed for simultaneous quantification of five pure compounds (1–5). Seasonal variation study revealed higher content of these compounds during the rainy season. The chloroform (CPCF) and n-butanol (CPBF) fractions showed cytotoxic efficacy against KB cells. Among pure compounds, hayatinine (5) was found to be most active against KB and A549, while, cycleanine (6) against KB cells. 相似文献
380.
Singh Mayur Pratap Arora Kanwer Singh Shajan Nikhil Pandu Sangeetha Ranga Shome Mahadev Kumar Rajneesh Shukla Dinesh 《Journal of Thermal Analysis and Calorimetry》2019,137(4):1155-1167
Journal of Thermal Analysis and Calorimetry - Continuous cooling transformation diagrams were obtained for a simulated coarse-grain heat-affected zone of API X-80 and X-65 steels using Gleeble-3800... 相似文献