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41.
Mani Neema Pallikkarathodi Cyriac Jobin 《Analytical and bioanalytical chemistry》2019,411(21):5481-5488
Analytical and Bioanalytical Chemistry - The mechanism behind the variation in the photoluminescence (PL) of a MoS2 nanohybrid material with pH was investigated. Highly fluorescent MoS2 quantum... 相似文献
42.
In this paper, we have investigated the response of long period grating (LPG) as refractive index sensor. The response has been studied for refractive index variation ranging from 1 to 1.45. In this work, we found that the sensing mechanism is based on two different aspects. First is the change of coupling power from the guided core mode to other co-propagating cladding modes and second is the wavelength shift of the peak resonant wavelengths from their original positions due the change of refractive index of the environmental (external) medium surrounding the cladding of the grating. 相似文献
43.
Anish Khan Aftab Aslam Parwaz Khan Abdullah M. Asiri Malik Abdul Rub Naved Azum Mohammed M. Rahman Sher Bahadar Khan Sulaiman Ab Ghani 《Applied biochemistry and biotechnology》2013,169(6):1927-1939
Technology always has been an indispensible part in the development of biosensors. The performance of biosensors is being tremendously improved using new materials as transducer as well as binding material in their construction. The use of new materials allowed innovation on transduction technology in biosensor preparations. Because of the submicron dimensions of these sensors, simple and rapid analyses in vitro as well as in vivo are now possible. Portable instruments capable of analysing multiple components are becoming available, too. Sensors that provide excellent temporal and spatial resolution for in vivo monitoring such as for measurement of neurotransmitters have become prominent. The interest to improve the stability, sensitivity and selectivity of the sensors is paramount. This study tries to give an overview of the present status of the material-based biosensor design and new generation of choline/acetylcholine neurotransmitter biosensors. 相似文献
44.
K.B. Jose J. Cyriac J. T. Moolayil V.S. Sebastian M. George 《Journal of Physical Organic Chemistry》2011,24(8):714-719
We have studied the kinetics and elucidated the mechanism by DFT calculation of the reaction between ethanolamine (EOA) and 1‐fluoro‐2,4‐dinitrobenzene (DNFB) in acetonitrile and toluene. To determine the contribution of the nitro group, the activation energy of the reaction between ethanolamine and 1‐fluoro‐2‐nitrobenzene (MNFB) vs. DNFB was determined in acetonitrile and calculated by DFT method. Kinetic measurements reveal that the reaction is faster in acetonitrile than in toluene. The reaction follows overall second‐order kinetics: first order with respect to both EOA and DNFB which is similar to the results reported for reaction between other primary amines and 1‐substituted‐2,4‐dinitrobenzenes. The calculations by using DFT methods reveal that the mechanism of the reaction involves the formation and decomposition of a Meisenheimer complex (MC). DFT calculations also reveal that the activation energy of the reaction is highest in vacuum and decreases with increasing polarity of the solvent reaching a minimum in acetonitrile. In addition, activation energies obtained by both DFT calculations and experiments show that the reactivity of MNFB is less than that of DNFB showing the effect of the 4‐nitro group. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
45.
Dr. Sebastian Götze Dr. Nahid Azzouz Dr. Yu‐Hsuan Tsai Prof. Dr. Uwe Groß Anika Reinhardt Dr. Chakkumkal Anish Prof. Dr. Peter H. Seeberger Dr. Daniel Varón Silva 《Angewandte Chemie (International ed. in English)》2014,53(50):13701-13705
Around 2 billion people worldwide are infected with the apicomplexan parasite Toxoplasma gondii which induces a variety of medical conditions. For example, primary infection during pregnancy can result in fetal death or mental retardation of the child. Diagnosis of acute infections in pregnant women is challenging but crucially important as the drugs used to treat T. gondii infections are potentially harmful to the unborn child. Better, faster, more reliable, and cheaper means of diagnosis by using defined antigens for accurate serological tests are highly desirable. Synthetic pathogen‐specific glycosylphosphatidylinositol (GPI) glycan antigens are diagnostic markers and have been used to distinguish between toxoplasmosis disease states using human sera. 相似文献
46.
Aftab Aslam Parwaz Khan Anish Khan Abdullah M. Asiri Naved Azum Malik Abdul Rub Sher Bahadar Khan Mohammed M. Rahman Abdulrahman O. Al-Youbi 《Research on Chemical Intermediates》2014,40(4):1703-1714
The mechanism of dismutation of MnO4 2? via the complex [MTZ–MnO4·OH]2?, formed during the oxidation of metronidazole (MTZ), has been investigated spectrophotometrically at different temperatures. The stoichiometry of the reaction is 1:1, i.e. 1 mol MTZ reacts with 1 mol Mn(VII).The reaction is first order in permanganate, less than first order in [MTZ] and [alkali]. The effects of added products and the dielectric constant and ionic strength of the reaction medium were investigated. The main products were identified by spot test and FT-IR. A mechanism involving a free radical has been proposed. In the equilibrium step MTZ binds to the MnO4 ? species to form a complex (C). Investigation of the reaction at different temperatures enabled determination of the activation data for the slow step of proposed mechanism. The proposed mechanism and the derived rate laws are consistent with the observed kinetics. 相似文献
47.
Chayan Patra Valay Agarawal Dipanjali Halder Anish Chakraborty Dibyendu Mondal Sonaldeep Halder Rahul Maitra 《Chemphyschem》2023,24(4):e202200633
The coupled cluster iteration scheme for determining the cluster amplitudes involves a set of nonlinearly coupled difference equations. In the space spanned by the amplitudes, the set of equations are analyzed as a multivariate time-discrete map where the concept of time appears in an implicit manner. With the observation that the cluster amplitudes have difference in their relaxation timescales with respect to the distributions of their magnitudes, the coupled cluster iteration dynamics are considered as a synergistic motion of coexisting slow and fast relaxing modes, manifesting a dynamical hierarchical structure. With the identification of the highly damped auxiliary amplitudes, their time variation can be neglected compared to the principal amplitudes which take much longer time to reach the fixed points. We analytically establish the adiabatic approximation where each of these auxiliary amplitudes are expressed as unique parametric functions of the collective principal amplitudes, allowing us to study the optimization with the latter taken as the independent degrees of freedom. Such decoupling of the amplitudes significantly reduces the computational scaling without sacrificing the accuracy in the ground state energy as demonstrated by a number of challenging molecular applications. A road-map to treat higher order post-adiabatic effects is also discussed. 相似文献
48.
Verhoeff AA Kistler ML Bhatt A Pigga J Groenewold J Klokkenburg M Veen S Roy S Liu T Kegel WK 《Physical review letters》2007,99(6):066104
We show that the equilibrium size of single-layer shells composed of polyoxometalate macroions is inversely proportional to the dielectric constant of the medium in which they are dispersed. This behavior is consistent with a stabilization mechanism based on Coulomb repulsion combined with charge regulation. We estimate the cohesive energy per bond between macroions on the shells to be approximately -6kT. This number is extracted from analysis based on a charge regulation model in combination with a model for defects on a sphere. The value of the cohesive bond energy is in agreement with the model-independent critical aggregate concentration. This observation points to a new class of thermodynamically stable shell-like objects. We point out the possible relevance our findings have for certain surfactant systems. 相似文献
49.
A C-scan ultrasonic imaging system was used to investigate the microstructural evolution during dynamic recrystallization (DRX) of a 15Cr–15Ni–2.2Mo–Ti modified austenitic stainless steel (alloy D9). Four specimens were forged at 1273 K to different strains in the range 0.1–0.5. Specimens with true strains of 0.2 or lower did not show any variation in the amplitude of the first back-wall echo. However, a visible variation in the C-scan image was observed at and above the 0.3 strain level. This variation was attributed to the evolution of fine grains. The formation of fine grains was related to DRX, as indicated by electron backscattered diffraction. This study also revealed the characteristics of the DRX or ‘necklace grains’, as opposed to the so-called parent grains or rest of the microstructure. 相似文献
50.
Anish Ghosh 《Monatshefte für Mathematik》2011,19(4):281-299
We prove the convergence case of the Khintchine–Groshev theorem for affine subspaces and their nondegenerate submanifolds,
answering a conjecture of D. Kleinbock. 相似文献