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1.
The frequency and the amplitude of the driving AC current dependence on the harmonic behavior of the giant magneto-impedance (GMI) voltage of Co-rich amorphous wire have been studied. Single-peak, two-peak and three-peak behavior in the GMI characteristics was studied with the change of amplitude and frequency of the AC current. GMI ratio was calculated from the first harmonic signals which were initially increased and then decreased monotonically with the increase of frequency (f) and the amplitude (IAC) of the driving current. The response of the GMI voltage was found non-linear with the generation of higher harmonics at higher amplitude of the driving current. The second and third harmonic signals were also evaluated and their dependence on the driving current amplitude and frequency were presented in the paper. The experimental results were analyzed using single domain rotational model. The voltage harmonics were calculated through Fourier transform of the time derivative of the estimated circular magnetization of the sample. 相似文献
2.
Summary N-(orthovanillidene)L-alanine (OVAlaH2), N-(salicylidene)L-valine (SValH2), N-(orthovanillidene)L-valine (OVValH2), N-(orthovanillidene)L-tyrosine (OVTyrH3) and N-(salicylidene)L-glutamic acid (SGluH3) react with LaIII, PrIII, NdIII and SmIII to yield new chiral complexes. Their dominant conformers were determined from c.d. spectra supported by1H n.m.r. data, except for the L-glutamic acid derived complexes which were insoluble. 相似文献
3.
The bis(chelated) complex of CrV(0) derived from the dianion (L2
−) of 2-ethyl-2-hydroxybutanoic acid is readily reduced to a bis(chelate of CrIII, featuring the monoanion (LH−) [Cr
V(0)(L2−)2]−+4H++H2O+2e−→[CrIII(OH2)2(LH−
2]+ of this acid. Potentials estimated by Ghosh in 1993 for this 2e− change, E0 (pH 0) 1.32 V, Eeff (pH 3.3) 0.93 V, are in accord with the nearly irreversible reductions of the Cr(V) species (in 1∶1 ligand buffer) by Fe2+, V02+, IrCl6
3
− and I−, whereas lower values reported by Bose in 1996, E0 (pH 0) 0.84 V, Eeff (pH 3.3) 0.45 V, are potentiometrically inconsistent with these conversions. A similar discrepancy is noted for potentials
for Cr(V,IV) estimated in 1996, E0 (pH 0) 0.84 V, Eeff (pH 3.3) 0.46 V, which, wholly contrary to observation, predict that the reductions of excess Cr(V) to CR(IV) by Fe2+, V02+, and I− are thermodynamically disfavored. 相似文献
4.
Papia Datta Dibakar Sardar Uttam Panda Ajanta Halder Nabin Baran Manik Chun‐Jung Chen Chittaranjan Sinha 《应用有机金属化学》2016,30(5):323-334
Os(II) hydridocarbonyl complexes of coumarinyl azoimidazoles, [Osh(CO)(PPh3)2(CZ‐4R‐R′)]0/+ ( 3 , 4 ) (CZ‐R‐H = 2‐(coumarinyl‐6‐azo)‐4‐substituted imidazole or 1‐alkyl‐2‐(coumarinyl‐6‐azo)‐4‐substituted imidazole), were characterized from spectroscopic data and the single‐crystal X‐ray data for one of the complexes, [Osh(CO)(PPh3)2(CZ‐4‐Ph)] ( 3c ) (CZ‐4‐Ph = 2‐(coumarinyl‐6‐azo)‐4‐phenylimidazolate), confirmed the structure. The complexes show higher emission (quantum yield ? = 0.0163–0.16) and longer lifetime (τ = 1.4–10.3 ns) than free ligands (? = 0.0012–0.0185 and τ = 0.685–1.306 ns). Cyclic voltammetry shows quasi‐reversible metal oxidation at 0.67–0.94 V for [Os(III)/Os(II)] and 1.21–1.36 V for [Os(IV)/Os(III)] and subsequent azo reductions (?0.68 to ?0.95 V for [? N?N? ]/[? N N? ]? and irreversible < ?1.2 V for [? N N? ]?/[? N? N? ]2?) of the chelated coumarinyl azoimidazole. The complexes are photostable and show better photovoltaic power conversion efficiency than free ligands. Also, the complexes were used as catalysts for the oxidation of primary/secondary alcohols to aldehydes/ketones using oxidizing agents like N‐methylmorpholine N‐oxide, t‐BuOOH and H2O2. Density functional theory computation was carried out from the optimized structures and the data obtained were used to interpret the electronic and photovoltaic properties. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
5.
Cellulose - This study explores the hybridizing effect of mechano-chemical activated fly-ash (FA) in polypropylene (PP) composites reinforced with sisal fibers. Activation and resistance against... 相似文献
6.
Manik Pavan Maheswaram Dhruthiman Mantheni Indika Perera Hareesha Venumuddala Alan Riga Kenneth Alexander 《Journal of Thermal Analysis and Calorimetry》2013,111(3):1987-1997
Morphological and thermodynamic transitions in drugs as well as their amorphous and crystalline content in the solid state have been distinguished by thermal analytical techniques, which include dielectric analysis (DEA), differential scanning calorimetry (DSC), and macro-photomicrography. These techniques were used successfully to establish a structure versus property relationship with the United States Pharmacopeia standard set of active pharmaceutical ingredient (API) drugs. A distinguishing method is the DSC determination of the amorphous and crystalline content which is based on the fusion properties of the specific drug and its recrystallization. The DSC technique to determine the crystalline and amorphous content is based on a series of heat and cool cycles to evaluate the drugs ability to recrystallize. To enhance the amorphous portion, the API is heated above its melting temperature and cooled with liquid nitrogen to ?120 °C (153 K). Alternatively a sample is program heated and cooled by DSC at a rate of 10 °C min?1. DEA measures the crystalline solid and amorphous liquid API electrical ionic conductivity. The DEA ionic conductivity is repeatable and differentiates the solid crystalline drug with a low conductivity level (10?2 pS cm?1) and a high conductivity level associated with the amorphous liquid (106 pS cm?1). The DSC sets the analytical transition temperature range from melting to recrystallization. However, analysis of the DEA ionic conductivity cycle establishes the quantitative amorphous and crystalline content in the solid state at frequencies of 0.10–1.00 Hz and to greater than 30 °C below the melting transition as the peak melting temperature. This describes the “activation energy method.” An Arrhenius plot, log ionic conductivity versus reciprocal temperature (K?1), of the pre-melt DEA transition yields frequency dependent activation energy (E a, J mol?1) for the complex charging in the solid state. The amorphous content is inversely proportional to the E a where the E a for the crystalline form is higher and lower for the amorphous form with a standard deviation of ±2%. There was a good agreement between the DSC crystalline melting, recrystallization, and the solid state DEA conductivity method with relevant microscopic evaluation. An alternate technique to determine amorphous and crystalline content has been established for the drugs of interest based on an obvious amorphous and crystalline state identified by macro-photomicrography and compared to the conductivity variations. This second “empirical method” correlates well with the “activation energy” method. 相似文献
7.
Salaam Saleh Druthiman Reddy Mantheni Manik Pavan Kumar Maheswaram Susan Moreno-Molek Tobili Sam-Yellowe Alan T. Riga 《Journal of Thermal Analysis and Calorimetry》2013,111(3):1707-1716
Malaria affects over 500 million people worldwide leading to 1–2 million deaths each year, the majority of whom are children. Four Plasmodium species cause malaria in humans. To properly diagnose, and correctly treat malarial infections, accurate diagnosis of infection is required. Proper diagnosis of infection will result in a reduction of morbidity, mortality, and of drug resistant parasites. However, the current tests for malaria diagnosis do not efficiently identify the appropriate human and parasite biomarkers associated with disease. Detection of specific inflammatory mediators such as cytokines associated with malaria pathogenesis will aid the determination of disease progression, disease prognosis, and the early diagnosis of malaria infection. In this study, we used dielectric thermal analysis (DETA), thermogravimetric analysis, and differential scanning calorimetry (DSC) to characterize five human cytokines (IL-1α, IL-2, IL-4, IL-6, and IL-10), to demonstrate how their thermoanalytical properties can be investigated for sensor design. Analysis for DETA was performed at a frequency range of 0.1–300,000 Hz. Permittivity and loss factor measurements were used to calculate tan δ values. Peak frequencies were used to determine dielectric signatures for each cytokine. The peak frequencies were different for each cytokine analyzed. In addition, activation energies were frequency dependent for IL-2 but frequency independent for the remaining four cytokines. Cytokines were also examined using DSC which established variance in heat of crystallization and heat of fusion of solvent among the five cytokines. A noticeable differentiation was observed with IL-1α among the other four cytokines when analyzed using trend analysis. Detection of unique dielectric signals will aid development of sensitive dielectric sensors capable of detecting cytokines in various human samples. 相似文献
8.
Aasif Helal Hyun Gon Kim Manik Kumer Ghosh Cheol-Ho Choi Sung-Hong Kim Hong-Seok Kim 《Tetrahedron》2013
Two new reactive and highly selective turn-on fluorescent chemosensors based on the position of ring annulation of the naphthalene–thiazole moiety for aluminum ions in ethanol, were synthesized and investigated. It was found that sensors 2 and 4 exhibited a remarkable enhancement of emission upon complexation with Al3+. A TD-B3LYP/6-31G(d,p) calculation was performed to characterize the nature of the fluorescence behavior of sensors 2 and 4 upon Al3+ complexation. The mechanism of fluorescence was based on the cation promoted hydrolysis of ester and subsequent complexation. The combination of experimental and computational analyses provides a more complete understanding of the molecular level origin of these types of unique photophysical properties. 相似文献
9.
The surface reaction pathways of isothiazole and thiazole on Si(100)?2?×?1 surface were theoretically investigated using multireference wavefunctions. In the case of isothiazole, the Si?CN dative adduct turned out to be the major surface product. In contrast, a direct reaction competition between a concerted [4?+?2]CC cycloaddition and Si?CN dative adduct was found in the adsorption of thiazole. Therefore, it is concluded that the particular geometric arrangements of heteroatoms exhibit distinctly different initial surface reaction mechanisms. 相似文献
10.
In this present investigation, we describe the steady state current voltage (I–V) characteristic of Crystal violet dye dispersed
solid state photoelectrochemical cell (PEC). Typical behavior of dark current-voltage characteristic by increasing and decreasing
external bias voltage has a similar form like hysterisis in nature. Although we have already observed this hysterisis nature
in case of both forward and reverse bias condition, yet it is clear that the reverse hysterisis curve is more prominent than
forward hysterisis. In this paper, we are getting double values of current (I) for a single value voltage, which is also helpful
to understand the charge transport process through disordered materials. As the bias increases, the distribution of traps
depth, which is exponential in nature, changes toward order state (resulting increase in disordered parameter α) This means
that as α increases, it tends to reach the most order state of material. When external bias voltage is at 3.5 V, the value
of disorder parameter becomes 1, and when bias voltage is beyond 3.5 V, the diffusion comes enhanced in nature. 相似文献