共查询到20条相似文献,搜索用时 0 毫秒
1.
Prakash ThangarajJayaprakash Rajan Sathyaraj DuraiSanjay Kumar Ayalsomayajula RatnaPhaniGiovanni Neri 《Vacuum》2011,86(2):140-143
The size controlled zinc oxide nanoparticle is synthesized in the isothermal evaporation method with albumen (egg white). This method is simple and cost effective for synthesis of ZnO nano powder. The egg white foam was assisted to increase the reaction rate and produce the zinc oxide nano powder. This method helps to attain the particle size in the range 13-28 nm. The results from X-ray diffraction patterns and TEM micrograph confirmed the formation of nano crystalline phase with particle size ranges from 13 nm to 28 nm. The samples were further analyzed by using Fourier transform Infrared spectroscopy (FT-IR), photoluminescence spectrum (PL), thermogravimetric analysis (TGA) and Resistivity measurement. The less time consumption in isothermal evaporation process was one of the significant roles for large scale zinc oxide nano powder production. 相似文献
2.
Youngsoo Jung Erica Stevens Bo Ding Sun-Dong Kim Sang-Kuk Woo Jung-Kun Lee 《Journal of Materials Science》2013,48(10):3760-3768
We study the effects of particle morphology on the microstructure and electrical conductivity of Mo particle thick films. In our study, the shape and size of molybdenum (Mo) particles are modified by mechanical ball-milling and atomic layer deposition (ALD). As the total number of collisions between Mo particles and ball-milling media increases, Mo particles are deformed, and the shape of Mo particles changed from irregular polyhedrons to thin flakes. In the ball-milling process, stress frequency is an important processing parameter governing the deformation and breakage of Mo particles. In addition, ALD-grown TiO2 layer is found to significantly suppress the growth of Mo particles at high temperature. After 1000 °C annealing, the particle size of the TiO2 layer-coated film is only half of that of bare Mo particle films. The shape of the particles changes electrical conductivity of the Mo thick films. Large contact area between flake shape particles can increase the carrier mobility of the film and the 5-nm thick TiO2 layer can provide the inter-particle carrier transport path via a tunneling mechanism. Our results show that the combined use of the ball-milling and the ALD coating leads to Mo thick films with high electric conductivity and large surface area. 相似文献
3.
Yulong Zhang Ye Yang Junhua Zhao Ruiqin Tan Weiyan Wang Ping Cui Weijie Song 《Journal of Materials Science》2011,46(3):774-780
Aluminum-doped zinc oxide nanopowders were prepared using a surfactant assisted complex sol–gel method, and were characterized
using inductively coupled plasma, X-ray diffraction, scanning electron microscopy/energy dispersive X-ray spectroscopy, X-ray
photoelectron spectroscopy, and UV–Vis spectroscopy. Al was effectively doped into the ZnO matrix with concentrations up to
6.00 atomic ratio percents (at.%). X-ray diffraction results revealed that all of the nanoparticles had a pure hexagonal wurtzite
structure free of any impurities when annealing temperature was below 1273 K. The optical band gap of the nanopowders, which
was affected by the Al-doping concentration, reached a maximum of 3.43 eV when ZnO was doped with 4.00 at.% Al. The effect
of post-annealing temperature and vacuum conditions on the resistivities of the Al-doped ZnO nanoparticles was also investigated.
And the lowest volume resistivity (1.2 Ω cm) was achieved by annealing the Al-doped ZnO nanoparticles in a vacuum at 1173 K
for 2 h. 相似文献
4.
《Materials Letters》2006,60(25-26):3133-3136
Needle-like zinc oxide with high electrical conductivity has been successfully prepared in large-scale from calcining the need-like precursor synthesized by a simple co-precipitation approach with ZnCl2 as Zinc source, GaCl3 as Gallium source and NH4HCO3 as precipitant under an optimized conditions (45 °C and pH = 7.4–7.5). The as-fabricated products were characterized by means of TEM, SEM, XRD, EDS and XPS. Their electrical conductivities were also studied, showing that the volume resistivity of the needle-like zinc oxide with 2.2 mol% Ga3+ dopant was lower than 20 Ω·cm. 相似文献
5.
An indirect method of estimation of size distribution of nanoparticles in a nanocomposite is proposed in this paper. The present approach exploits DC electrical current–voltage characteristics (CVC) of ZnO nanocomposite specimen in bio-polymer background. The nature of DC CVC is found to be oscillatory with respect to applied voltage. The nature of CVC is a consequence of Coulomb blockade (CB) phenomena of electrical conduction through a tiny nanoparticle. Considering the ZnO nanocomposites to be spherical, Coulomb-blockade model of quantum dot is applied here. The size distribution of particle is estimated from that model and compared with the results obtained from AFM and XRD analyses. The results from CVC are found to be consistent with these conventional microscopic results. 相似文献
6.
We investigated the size-dependent electrical conductivities of indium zinc oxide stripes with different widths from 50 nm to 4 microm and with the same thickness of 50 nm deposited by RF magnetron sputtering. The size of the indium zinc oxide stripes was controlled by e-beam lithography. The distance of the two Ti/Au Ohmic electrodes along the indium zinc oxide stripes was kept constant at 25 microm. The electrical conductivity decreased as the size of the indium zinc oxide stripes decreased below a critical width (80 nm). The activation energy, derived from the electric conductivity versus temperature measurement, was dependent on the dimensions of indium zinc oxide stripes. These results can be understood as stemming from surface charge trapping from the absorption of oxygen and/or water vapor, which leads to an increase in the energy difference between the conduction energy band and the Fermi energy. 相似文献
7.
《Advanced Powder Technology》2023,34(8):104086
Multi-functional shear thickening fluids (M-STFs) with both shear thickening behavior and electrical conductivity have a great potential for usage in a variety of applications ranging from intelligent anti-impact and vibration damping structures to effective electric mechanical platforms. However, the influences of conductive fillers on the rheological behavior and electrical conductivity of M-STFs remained unclear. In this study, the role of conductive fillers including multi-walled carbon nanotubes (MWCNTs), carbon nanofibers (CNFs), and mixtures of MWCNT/CNF was investigated through the response surface methodology (RSM) in the temperature range of 0 °C to 60 °C. The individual and combined effects of filler content, temperature, and type of fillers on the electrical resistance and rheological behavior of M-STFs were studied. The results revealed the significant role of conductive fillers on the rheological properties and electrical conductivity of M-STFs. It is found that the initial viscosity of M-STF increases with increasing the filler content. Moreover, the M-STFs containing CNF exhibits higher electrical conductivity and lower percolation threshold (0.4 wt%). The results of this work provide new insights for the development of novel STF-based systems with multi-functional properties. 相似文献
8.
Z. A. Munir 《International Journal of Thermophysics》1981,2(2):177-186
The conductivity of undoped and doped uranium dioxide was investigated over the temperature range of approximately 300–1600 K. Activation energies calculated for the undoped samples and those doped with Cr2O3 and Gd2O3 are in agreement with previously published values. The values calculated for TiO2- and La2O3-doped samples were nearly twice that for the undoped UO2. The addition of Nb2O5 resulted in the extension of the intrinsic region of conductivity to lower temperatures than had been previously reported. The dependence of the extrinsic conductivity of Gd2O3- and Cr2O3-doped samples on the dopant level supports an impurity compensation model of conduction. 相似文献
9.
We report here the capping of iron oxide nanoparticles with dimethyl sulfoxide (DMSO) to make chloroform soluble iron oxide
nanoparticles. Size and shape of the capped iron oxide nanoparticles are well controlled by simply varying the reaction parameters.
The synthesized nanocrystallites were characterized by thermal analysis (TG-DTA), powder X-ray diffraction (XRD), transmission
electron microscopy (TEM) for evaluating phase, structure and morphology. 1H NMR spectra of the synthesized samples confirm DMSO, and the capping of DMSO on the ferrite samples. Shift of the S=O stretching
frequency in Fourier transformed infra-red (FTIR) spectra indicates that the bonding between DMSO and ferrite is through an
oxygen moiety. The magnetic measurements of all the synthesized samples were investigated with a SQUID magnetometer which
shows that the magnetic properties are strongly dependent on the size as well as shape of the iron oxide. 相似文献
10.
Cerium oxide (CeO2) nanoparticles have been synthesized through composite-hydroxide-mediated approach. The X-ray powder diffraction (XRD) measurement proved that the pure cubic CeO2 could be obtained at a low temperature region (170-220 °C). The particle size, micrograph morphology and microstructure were investigated by transmission electron microscope (TEM) and environmental scanning electron microscope (ESEM). The conductivity of as-synthesized CeO2 was measured by a standard four-probe method. The conductivity of CeO2 increases slightly with the increase of temperature. And the conductivity increases rapidly to 0.02418 s cm− 1 at 830 °C. The product is a potential material for intermediate temperature solid oxide fuel cells (ITSOFC). 相似文献
11.
da Silva Guilherme Donizeti Tamashiro Jacqueline Roberta Martins Bruna Letícia de Queiroz-Fernandes Geisiany Maria de Morais Chaves Marcia Rodrigues Pires Regina Helena Kinoshita Angela 《Journal of Materials Science》2022,57(4):2697-2709
Journal of Materials Science - Gypsum plaster is used in linings, coatings, decorative elements, and sealing and is a component of drywall. However, it is susceptible to the development of mold and... 相似文献
12.
Conductivity measurements reported previously for thin films of poly(divinylbenzene) have been interpreted in terms of a quantum mechanical tunneling conductivity mechanism. Quantum mechanical tunneling of carriers through thin spots (5–45 Å) in films having dielectric thickness of a few hundred Å is more consistent with the reported current-voltage-temperature characteristics than the previously suggested Richardson-Schottky mechanism. 相似文献
13.
Integration of zinc oxide nanoparticles into transparent poly(butanediolmonoacrylate) via photopolymerisation 总被引:1,自引:0,他引:1
A new method for the preparation of transparent ZnO/PBDMA nanocomposites (PBDMA = poly(butanediolmonoacrylate)) is reported. Zinc oxide nanocrystals (4-10 nm) were synthesized in ethanol and then transferred into butanediolmonoacrylate (BDMA) to obtain a transparent and stable colloidal suspension. No further growth or aggregation of the particles could be observed, after dispersing the particles in the monomer. Effective size control in the range of 6-10 nm and concentrations up to 10 wt% zinc oxide were demonstrated for these systems. The particles and suspensions were characterized by transmission electron microscopy, X-ray diffraction, UV-VIS spectroscopy and dynamic light scattering. The addition of trimethylolpropane triacrylate (TMPTA) and a photoinitiator to the ZnO/BDMA suspension lead to a UV-curable liquid. Photoinduced polymerization was used to produce transparent nanocomposites containing the nanoparticles. The material exhibits a strong UV absorption below 360 nm, a high transmission (90%) in the visible spectral range and a green photoluminescence. 相似文献
14.
Kinetics and tissue distribution of neutron-activated zinc oxide nanoparticles and zinc nitrate in mice: effects of size and particulate nature 总被引:1,自引:0,他引:1
Yeh TK Chen JK Lin CH Yang MH Yang CS Chou FI Peir JJ Wang MY Chang WH Tsai MH Tsai HT Lin P 《Nanotechnology》2012,23(8):085102
Although zinc oxide nanoparticles (ZnONPs) have been applied in nanotechnology, their kinetics and tissue distribution in?vivo are unknown. Here we compared the kinetics and tissue distribution of 10?nm (65)ZnONPs, 71?nm (65)ZnONPs and (65)Zn(NO(3))(2) in mice after intravenous injection. The areas under the curves and the half-lives in the second compartment of (65)Zn(NO(3))(2) were greater than those of (65)ZnONPs; the kinetic parameters were similar for both (65)ZnONPs. However, the tissue distributions for the three forms were different. ZnONPs preferentially accumulated in the liver and spleen at 24?h. At day 28, (65)Zn concentration was highest in bone and the proportion of recovered (65)Zn radioactivity was highest in the carcass; these had the same ranking, 10?nm (65)ZnONPs?>?71?nm (65)ZnONPs> (65)Zn(NO(3))(2). Although more than 80% of the 10?nm (65)ZnONPs had been excreted by day 28, greater amounts of the 10?nm (65)ZnONPs than the 71?nm (65)ZnONPs or (65)Zn(NO(3))(2) had accumulated in other organs (brain, lung, heart and kidneys). Zn ions seem to have a longer half-life in the plasma, but ZnONPs show greater tissue accumulation. Although the size of the ZnONPs had no obvious effect on the kinetics, nevertheless the smaller ZnONPs tended to accumulate preferentially in some organs. 相似文献
15.
We investigated the toxic effects of inhalation exposure to ferric oxide (Fe2O3) and zinc oxide (ZnO) nanoparticles in rats. Male Wistar rats were consecutively treated with Fe22O3 at 8.5 mg/kg body weight and ZnO nanoparticles at 2.5 mg/kg body weight, twice daily for 3 days. Content of Fe2O3 and ZnO in tissues, biochemical parameters in serum, and hispathological examinations were analyzed at 12 h and 36 h after the 3 day treatment. In the Fe2O3-treated group, iron (Fe) content in liver and lung tissues was significantly increased at 36 h. In the ZnO-treated group, zinc (Zn) content in liver tissues was significantly increased at 12 h and further increased at 36 h. The levels of serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), total protein (TP), creatine kinase (CK), and lactate dehydrogenase (LDH) in both nanoparticle-exposed groups were significantly decreased compared to the unexposed controls. Histopathological examination showed that both types of nanoparticles caused severe damage in liver and lung tissues. Although this damage progressed in both liver and lung throughout the postexposure period, no significant elevation of serum enzyme activities was observed in response to either nanoparticle type. 相似文献
16.
双酚A环氧树脂(EP)因其具有优异电绝缘性能而被广泛应用于电子器件中,但EP的热导率较低,通过填充高导热无机填料而构建导热通路是当前提高聚合物复合材料热导率的有效策略。本文综合利用溶液共混与热压工艺制备得到了六方氮化硼(h-BN)-四针状氧化锌晶须(T-ZnOw)/EP复合材料,并对复合材料的微观形貌与物相结构、导热性能及绝缘性能进行了系统表征与分析。结果表明,复合填充h-BN-T-ZnOw/EP复合材料兼具良好的导热性和绝缘性,当h-BN-T-ZnOw的填充含量为30wt%/5wt%时,25℃下热导率为0.55 W/(m·K),相比于纯EP提升了2.9倍,同时复合材料体积电阻率大于1015Ω·m,表现出良好的绝缘性。 相似文献
17.
Yoshiaki Hattori Shinobu MukasaHiromichi Toyota Toru InoueShinfuku Nomura 《Materials Letters》2011,65(2):188-190
Nanoparticles are synthesized efficiently from zinc electrode by microwave plasma in liquid. The nanoparticles synthesized from alcohol resulted in pure zinc particles in the shape of spheres or hexagonal cylinders with a production rate of 3.3 g/h, and energy consumption of 267 J/mg for 1 mg. Whereas the nanoparticles synthesized in pure water are composed of Zn and ZnO. The Zn reacts with water through heat or the passage of time to become ZnO, releasing hydrogen gas. An upper disk placed 1 mm away from the electrode along with the bubbles generated simultaneously with the plasma ignition plays a key role in the synthesis of nanoparticles. 相似文献
18.
Le-chun JiLei Huang Yang LiuYi-qun Xie Feng LiuAi-yun Liu Wang-zhou Shi 《Thin solid films》2011,519(11):3789-3791
Zinc oxide/indium/zinc oxide multilayer structures have been obtained on glass substrates by magnetron sputtering. The effects of indium thickness on optical and electrical properties of the multilayer structures are investigated. Compared to a single zinc oxide layer, the carrier concentration increases from 8 × 1018 cm−3 to 1.8 × 1020 cm−3 and Hall mobility decreases from 10 cm2/v s to 2 cm2/v s for the multilayer structure at 8 nm of indium thickness. With the increase of indium thickness, the transmittance decreases and optical band gap shifts to lower energy in multilayer structures. Results are understood based on Schottky theory, interface scattering mechanism and the absorption of indium layer. 相似文献
19.
Mg-doped ZnO nanoparticles were successfully synthesized by sonochemical method. The products were characterized by scan electron microscopy (SEM) and X-ray powder diffraction (XRD). SEM images revealed that ZnO doped with Mg(II) nanoparticles and ZnO nanoparticles synthesized by the same strategy all had spherical topography. XRD patterns showed that the doped nanoparticles had the same crystals structures as the pure ZnO nanoparticles. The Mg-doped ZnO nanoparticles had larger lattice volume than the un-doped nanoparticles. X-ray photoelectron spectroscopy (XPS) not only demonstrated the moral ratio of Mg and Zn element on the surface of nanoparticles, but their valence in nanoparticles as well. The Mg-doped ZnO nanoparticles presented good properties in photocatalyst compared with pure ZnO nanoparticles. 相似文献