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91.
Electrical and dielectric properties of lithium manganate nanomaterials doped with rare-earth elements 总被引:1,自引:0,他引:1
Substituted LiRxMn2 − xO4 (R = La3+, Ce3+, Pr3+ and x = 0.00 − 0.20) nanoparticles are prepared by the sol–gel method and the consequent changes in their lattice structure, dielectric and electrical parameters are determined by XRD, ED-XRF, SEM, LCR meter bridge and dc electrical resistivity measurements. Diffraction data show that the samples are single-phase spinel materials with crystallites sizes between 21 and 38 nm. The lattice parameter, cell volume and X-ray density are found to be affected by doping the Li-manganate with the rare-earth elements. The ED-XRF analysis confirms the stoichiometric composition of the synthesized samples and SEM reveals their morphology. Calculated values of the dielectric constant (?) and the dielectric loss (tan δ) decrease with the frequency of the applied field. This is attributed to Maxwell–Wagner polarization. Replacement of manganese by the rare-earth elements results in an improvement in the structural stability of the material, which is considered to be useful for enhancement of the cycleability of the compounds when used in lithium rechargeable batteries, and increases significantly the values of ? and tan δ (except for Ce). Lithium manganate nanomaterials with high ? and low tan δ may be attractive for application in memory storage devices. 相似文献
92.
From the viewpoint of electronic and telecommunication devices, the electrical resistivity is required to be high to curb the eddy current losses for efficient performance at high frequencies. In the present work, Sr0.5Ba0.5Fe12O19 hexaferrite has been doped with a binary mixture of lanthanum and nickel using chemical co-precipitation method of synthesis. The crystallite size of the synthesized samples is estimated in the range of 36–58 nm and their structural analyses have confirmed a single magnetoplumbite phase. The magnitude of the dc-electrical resistivity is enhanced, by almost 100 times, but Curie temperature (TC) is reduced by doping with La–Ni, which has been explained on the basis of the exchange interactions. In addition, the doped samples exhibit very low dielectric constant (έ = 11–13) and low dielectric loss tangent (tan δ = 0.07–0.10) determined at a frequency of 1 MHz. These characteristics may be suitable for their potential application in electromagnetic attenuation materials and microwave devices. 相似文献
93.
Hafiz Muhammad Asif Javed Akbar Ali Qureshi Remsha Mehmood Muhammad Imran Tahir Sofia Javed Muhammad Sarfaraz M. Yasar Javaid Muhammad Awais Usman Ali 《International Journal of Hydrogen Energy》2021,46(27):14311-14321
Hydrogen treatment is a facile and efficient approach for the enhancement in the functioning of TiO2 nanoparticles for dye-sensitized solar cells (DSSC). In this work, TiO2 nanoparticles have been synthesized in the hydrogen environment followed by the deposition onto FTO glass substrates with various film thickness as photoanodes for DSSC. The synthesized hydrogen treated TiO2 nanoparticles based photoanodes have showed significantly improved photocurrent in the resulting fabricated devices. SEM and TEM analyses have confirmed the particle size and morphology of TiO2 nanoparticles at various magnifications. The crystalline structure and phase identification were studied by XRD analysis and Raman spectroscopic measurements. The UV–Vis spectroscopy analysis was carried out to find the response of samples for ultraviolet and visible light. The current-voltage measurements have confirmed the improvement of photocurrent that is principally due to improved photo-activity of hydrogen treated TiO2 nanoparticles. Moreover, hydrogen treated TiO2 nanoparticles-based photoanode with the film thickness of 11.65 μm has remarkably enhanced power conversion efficiency of 6.05% in DSSCs. The ability of highly photoactive hydrogen treated TiO2 nanoparticles will provide the new openings in different fields that include photo-electrochemical water splitting and in many other applications. 相似文献
94.
Pu Chun Ke Emily H. Pilkington Yunxiang Sun Ibrahim Javed Aleksandr Kakinen Guotao Peng Feng Ding Thomas P. Davis 《Advanced materials (Deerfield Beach, Fla.)》2020,32(18):1901690
Amyloidosis is a biophysical phenomenon of protein aggregation with biological and pathogenic implications. Among the various strategies developed to date, nanomaterials and multifunctional nanocomposites possessing certain structural and physicochemical traits are promising candidates for mitigating amyloidosis in vitro and in vivo. The mechanisms underpinning protein aggregation and toxicity are introduced, and opportunities in materials science to drive this interdisciplinary field forward are highlighted. Advancement of this emerging frontier hinges on exploitation of protein self-assembly and interactions of amyloid proteins with nanoparticles, intracellular and extracellular proteins, chaperones, membranes, organelles, and biometals. 相似文献
95.
Gao Wei Iqbal Javed Hu Ruilin 《Bulletin of Engineering Geology and the Environment》2021,80(8):6263-6274
Bulletin of Engineering Geology and the Environment - Soil-rock mixture (S-RM) exerts a major control on slope stability. Baidian County in southeastern China was selected as a case study to better... 相似文献
96.
Riaz Sharjeel Khan Mansoor Javed Umer Zhao Xiongwen 《Wireless Personal Communications》2022,123(2):1871-1881
Wireless Personal Communications - This work presents a novel frequency reconfigurable patch antenna design for Internet of Things (IoT) applications. The proposed antenna structure has hexagonal... 相似文献
97.
Lanka Tata Rao Prakash Rewatkar Satish Kumar Dubey Arshad Javed Sanket Goel 《国际能源研究杂志》2020,44(5):3893-3904
Miniaturization of devices, combined with other features such as portability, proneness to automation, rapid performance, amenability to integration, multiplexing, and cost-effectiveness, is rapidly increasing for various sensing and energy harvesting applications. One such emerging area is the development of microfluidic fuel cell on cellulose papers, which has enormous scope to optimize its performance. This is primarily because such devices eliminate the need for membranes as well as external pumps since they have built-in colaminar flow embedded capillaries. Such peripherals are usually used in conventional microfluidic fuel cells, which are fabricated using methods like photolithography, PDMS lithography, and 3D printing. This paper presents investigations on microfluidic paper–based fuel cells (MPFCs) with different cellulose absorbent pads for their performance optimization. Herein, the MPFC utilizes formic acid as fuel, oxygen from quiescent air as oxidant, and sulfuric acid as electrolyte for conducting ionic exchange under colaminar flow. The electrodes are realized through simple pencil strokes depositing a thin layer of graphite. The porous graphite electrodes act as diffusion agents breathing oxygen directly from the atmospheric air. Such an MPFC configuration, costing less than US $1, was optimized to achieve maximum energy density by examining various combinations of absorbent pads with different grades of cellulose papers. It is seen that the maximum open circuit potential is 0.46 V, while the maximum current and power densities are 1505.66 μAcm−2 and 173.97 μWcm−2, respectively, with a grade 6 absorbent pad. Such performance can be further enhanced by investigating MPFCs with various graphite pencils with a diverse number of strokes at different concentration levels. 相似文献
98.
Joynal Abedin Shamim Mahbub Mohammad Majibur Rahman Anamul Hoque Dileep Kumar Javed Masood Khan Ahmed M. El-Sherbeeny 《中国化学工程学报》2021,29(1):279-287
Herein, the interaction of a protein, bovine serum albumin (BSA), with tetradecyltrimethylammonium bromide (TTAB, a cationic surfactant), has been investigated using the conductivity measurement technique in pure water and some sodium salts (NaCl, Na2SO4, Na2CO3, and Na3PO4) solutions at temperature range of 295.15-320.15 K. Results reveal that, in the plot of specific conductivity versus the concentration of TTAB, only a single critical micelle concentration (cmc) was found for the TTAB + BSA mixed system in all solvents media studied. The addition of BSA in aqueous TTAB solution, the value of cmc undergoes a change from its pure form, which indicates the presence of strong interaction operating between the BSA and TTAB molecules. In aqueous system, the cmc values of the TTAB + BSA mixtures are obtained higher compared to the values found for single TTAB surfactant. However, the addition of salt decreases the cmc value of mixed TTAB + BSA system. The values of cmc of the BSA + TTAB mixed system at 310.15 K and 1.00 mmol·kg-1 ionic strength of salt followed the order: cmcNa2CO3 > cmcNa3PO4 > cmcNaCl > cmcNa2SO4. The cmc values of TTAB + BSA mixture were found to be lowered in urea solution within the concentrations studied. The values of degree of dissociation (α) and fraction of counter ion binding (β) were found to be dependent on additives and temperature. The free energy of micellization (△Gmo) is negative for all the systems, which manifests that the micellization phenomenon is energetically spontaneous. The enhancement of the negative value of △Gmo in aqueous salt solutions reveals an increase of spontaneity of the TTAB + BSA micellization process. The values of △Gmo also reveal that the spontaneity of micelle formation is enhanced at higher temperatures in all media studied. The values of free energy of transfer (△Gm, to) were also determined for numerous solvent media used in the present study and described with appropriate reasoning. 相似文献
99.
Javed A. Farooqi Sajid Jamal I. Ahmad 《Journal of the American Oil Chemists' Society》1985,62(12):1702-1703
Seed oil ofSemecarpus kurzii was found to contain 10.5% of 9-hydroxy-cis-12-enoic (isoricinoleic) acid along with the usual fatty acids. The identification of the hydroxy acid was made on the basis
of chromatographic, spectroscopic and chemical methods, with isoricinoleic acid used as the reference standard. 相似文献
100.
Sajid Jamal Javed A. Farooqi M. S. Ahmad Abdul Mannan 《Journal of the science of food and agriculture》1987,39(3):203-206
The seed oils of Acacia mollissima, A. torta, A. lenticularis and A. nilotica are found to contain 6.2, 5.3, 4.7 and 3.1%, respectively, cor-onaric acid in addition to other fatty acids. The structure of coronaric acid was established by chemical and physical methods using Chrysanthemum coronarium seed oil and its derived coronaric acid as the reference sample. 相似文献