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排序方式: 共有1916条查询结果,搜索用时 218 毫秒
91.
92.
93.
S. Narendra Babu A. Siddeshwar K. Srinivas S. V. Suryanarayana T. Bhimasankaram 《Journal of Materials Science》2009,44(15):3948-3951
A composite material when placed under the external magnetic/electric fields exhibits voltage/induced magnetization is known
as magnetoelectric (ME) composite. Such composite materials should have ferroelectric and ferro/ferri magnetic phases as constituents.
The magnetoelectric output is exhibited as a product property. Magnetoelectric composites are being used for variety of applications
including resonators, filters, phase shifters, optical isolators, actuators and magnetic field sensors. Metal/ferroelectric/metal
magnetoelectric composite using Ni and PZT as constituent phases has been fabricated in 2-2 composite pattern to study its
product property. The paper presents magnetoelectric studies of Ni/PZT/Ni composite using low dc magnetic field magnetoelectric
set-up. Using this ME set-up ME output of Ni/PZT/Ni composite is studied as a function of dc magnetic field. The results were
analyzed to identify the useful magnetic field (dc and ac) range in which Ni/PZT/Ni sensor can be utilized for applications. 相似文献
94.
B. Adhikari T. Howes B. R. Bhandari V. Truong 《International Journal of Food Properties》2013,16(3):323-351
Levitation and free‐flight techniques applied to investigate the drying kinetics and morphology of single drops containing dissolved solids and suspensions are reviewed. A review of works related to receding interface model proposed to quantify the drying kinetics of single drops along with techniques to measure the kinetic parameters such as moisture diffusivity, thermal conductivity and specific heat capacity is presented. Problems associated with spray drying of sugar‐rich compounds are briefly discussed and possible links of stickiness and flavor retention with glass transition temperature (Tg), temperature history, drying rate and morphological changes including skin formation, as monitored through single drop experiments, are explored. 相似文献
95.
Poly(m-aminophenol) (PmAP) was synthesized by the oxidative polymerization of m-aminophenol in sodium hydroxide medium using ammonium persulfate oxidant at room temperature. The synthesized polymer showed very good solution processability as it was well soluble in aqueous sodium hydroxide, dimethylsulfoxide (DMSO), dymethylformamide (DMF), etc. A free-standing film was cast from thermal evaporation of DMSO solution of the synthesized PmAP. The film was then doped with aqueous sodium hydroxide and methanol mixture by solution doping technique at room temperature. The doping conditions were standardized in terms of the DC-conductivity of the doped film. The doped PmAP was characterized by ultraviolet–visible spectroscopy, Fourier transform infrared spectroscopy, Electron dispersion spectroscopy, X-ray diffraction spectroscopy, elemental analysis by atomic absorption spectroscopy, thermogravimetric analysis and DC-electrical conductivity. The DC-electrical conductivity of PmAP film was increased to 2.34 × 10?5 S/cm from <10?12 S/cm due to sodium ion doping. From all the above characterizations it was confirmed that the sodium ions were not the reason for the conduction. The incorporated sodium cation in the polymer through free –OH groups of the polymer chain was induced the electron cloud of the polymer and so the polymer became conducting. 相似文献
96.
Phase separation has been recognized as important properties of manganite to create colossal magnetoresistance (CMR). Frequency dependence of AC susceptibility and electron spin resonance (ESR) studies confirm the phase separated glassy magnetism in the La0.9Pb0.1MnO3 crystals. ESR spectra exhibit a gradual narrowing of the asymmetric FMR signals upon increasing the temperature and approaching the Curie temperature (Tc). The temperature dependence of line width (ΔHpp), g-factor, double integrated (I) intensity of the resonance signals and frequency dependence peak temperatures are discussed in this paper to explain inhomogeneity in the La0.9Pb0.1MnO3 single crystals. 相似文献
97.
Band-gap tuning of pendant polymers for organic light-emitting devices and photovoltaic applications
Akhil Gupta Scott E. Watkins Andrew D. Scully Th. Birendra Singh Gerard J. Wilson Lynn J. Rozanski Richard A. Evans 《Synthetic Metals》2011,161(9-10):856-863
The preparation of a series of novel polymers comprising pendant electro-active “push–pull” chromophores and their performance in solution-processed organic electronic devices is described. The design of the electro-active pendant chromophores was based on the well-known motif of cyano-substituted poly(p-phenylenevinylene). Optical band-gap engineering within this series of polymers was achieved by varying the conjugation length and the electron donor/acceptor functionalities of the pendant chromophores. The introduction of a cyanoimine group into the electro-active pendant module resulted in a marked narrowing of the optical band-gap compared with the other electro-active pendant chromophores investigated in this work. Bulk heterojunction solar cell devices comprising these polymers were prepared by solution processing blends of each polymer with [6,6]-phenyl-C61-butyric acid methyl ester, and their performance was evaluated by measuring power conversion efficiencies. The best-performing solar cell in this series exhibited a power conversion efficiency of 0.29% and a maximum incident photon-to-current conversion efficiency of 22% and was produced using the polymer in which the electro-active chromophore comprised the cyanoimine group. 相似文献
98.
S.A.Saleem B.C.Jamalaiah A.Mohan Babu K.Pavani L.Rama Moorthy 《中国稀土学报(英文版)》2010,28(2):189-193
Glasses with chemical composition of (in mol.%): 26 RF-20 PbO-10 TeO2-43 H3BO3-1 EuO3 (RLTB) were prepared by conventional melt quenching method. The Judd-Ofelt intensity parameters Ω2 and Ω6 were obtained from the absorption intensities of 7F0→5D2 and 7F0→5L6 transitions, respectively. In order to overcome the problem of applicability of Judd-Ofelt analysis at room temperature due to the overlapping of the transitions originating from 7F0 and 7F1 levels of Eu3+ ion, the effect of the thermalization on the population of energy levels was taken into account. The photoluminescence spectra contained five emission bands originating from the 5D0 metastable state to 7FJ (J=0, 1, 2, 3, 4) lower lying states. The decay profiles were found to be single exponential in all the three glasses. The measured lifetimes (τmes) were in good agreement with the calculated lifetimes (τcal) obtained by using the thermally corrected Judd-Ofelt intensity parameters. 相似文献
99.
Gediminas Mainelis Klaus Willeke Atin Adhikari Tiina Reponen Sergey A. Grinshpun 《Aerosol science and technology》2013,47(11):1073-1085
We have developed and tested a new bioaerosol sampler in which airborne microorganisms are collected by electrostatic means. In this sampler, 2 ionizers charge the incoming particles if they carry insufficient electric charge for efficient collection. The organisms are then subjected to a precipitating electric field and are collected onto 2 square agar plates positioned along the flow axis. Tests with nonbiological NaCl particles versus B. subtilis var. niger (BG) spores and vegetative cells have shown that airborne microorganisms are collected more efficiently than nonbiological particles, even when the microorganisms have first passed through an electric charge neutralizer with no additional charging applied. The difference was attributed to the natural charges contained in cell membranes or spore coats of the microorganisms. Charge-neutralized BG spores and vegetative cells were collected at 4 L/min with efficiencies close to 80%, depending on the precipitation voltage, versus 50-60% for NaCl test particles. When incoming BG spores were charged with positive ions and then collected by a precipitating voltage of + 1,300 V, about 80% of the incoming spores were collected and more than 70% of incoming spores formed colonies. These experiments with BG spores have also indicated that there were no significant particle losses inside the sampler. The collection efficiency of biological and nonbiological particles increased to 90-100% when the particles were externally charged and the precipitating voltage was increased to more than - 4,000 V. It has also been shown that the aerosolized BG spores (used as anthrax simulants for bioaerosol sensors) carry a net negative electric charge. Thus the collection efficiency depends on the polarity of the electric field applied across the agar plates. These findings indicate that the collection of airborne microorganisms is possible by electrostatic precipitation without prior electric charging if the microorganisms already carry electric charges. These are usually high immediately after their release into the air. 相似文献
100.
Multi-objective differential evolution (MODE) is used to optimize an industrial styrene reactor considering productivity, selectivity and yield as the main objectives. Two reactor configurations (single bed adiabatic operation and steam injected pseudo-isothermal operation) and four combinations of objectives consisting of 5 and 7 variables respectively are considered. Pareto optimal solutions are obtained for all combinations of objective functions for both the configurations. The results are compared with those reported in the literature and an industrial operating point. For all the cases considered, MODE is able to give a Pareto front better (in terms of wider range and a better spread) than that obtained using NSGA for both the configurations. Steam injected reactor configuration is better than the adiabatic reactor configuration in terms of performance. The Pareto optimal solutions obtained from such studies provide a wide range of optimal operating conditions from which an appropriate operating point can be selected based on the requirements of the decision maker. 相似文献