• Transactions on Electrical and Electronic Materials
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• 제15권4호
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• pp.213-216
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• 2014

The microstructure and varistor properties of ZPCCAE ($ZnO-Pr_6O_{11}-CoO-Cr_2O_3-Al_2O_3-Er_2O_3$) ceramics were investigated with different erbium amounts. Analysis of the microstructure indicated that the ceramics consisted of ZnO grains as a bulk phase, and intergranular layers (mixture of $Pr_6O_{11}$ and $Er_2O_3$) as a minor secondary phase. With the increase of the doped erbium amount, the densities of sintered pellets increased from 5.63 to $5.82g/cm^3$, and the average grain size decreased from 9.0 to $5.7{\mu}m$. The increase of the doped erbium amount increased the breakdown field from 2,649 to 5,074 V/cm, and the nonlinear coefficient from 27.6 to 39.1. It was found that in the range of 0.25 to 0.5 mol%, the doped erbium had little effect on the microstructure and electrical properties.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 Techno-Fair 및 합동춘계학술대회 논문집 전기물성,응용부문
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• pp.169-170
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• 2008

The heterolayered PZT/PT thick films were fabricated by two different methods - thick films of the PZT by screen printing method on alumina substrates electrodes with Pt, thin films of $PbTiO_3$ by the spin coating method on the PZT thick films and once more thick films of the PZT by the screen printing method on the $BaTiO_3$ layer The structural and the dielectric properties were investigated for effect of various stacking sequence of sol-gel prepared $PbTiO_3$ coating solution at interface of the PZT thick films. The insertion of $PbTiO_3$ interlayer yielded the PZT thick films with homogeneous and dense grain structure with the number of $PbTiO_3$ layers. The leakage current density of the PZT/$PbTiO_3-1$ film is less that $4.41{\times}10^{-9}\;A/cm^2$ at 5 V.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 하계학술대회 논문집
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• pp.383-386
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• 2002

Polycrystalline Cu(In,Ga)Se$_2$(CIGS) thin-films were grown by co-evaporation on a soda lime glass substrate. In this paper the effects of the Se evaporation temperature on the properties of CuIn0.75Ga0.25Se2 (CIGS) thin films. Structure, surface morphology and optical properties of CIGS thin films deposited at various Se evaporation temperatures have been investigated using a number of analysis techniques. X-ray diffraction (XRD) analysis shows that CIGS films exhibit a strong <112> preferred orientation. As expected, at higher Se evaporation temperatures the films displayed a lower degree of crystallinity. The <112> peak was also enhanced and other CIGS peaks appeared simultaneously. These results were supported by experimental work using scanning electron microscopy When the Se evaporation temperature was increased, the average grain size also decreased together with a reduction Cu content. The Se evaporation temperature also had a significant inf1uence on the transmission spectra. Increasing the Se evaporation temperature, the cell efficiency was improved dramatically to 11.75% with Voc = 556 mV, Jsc = 32.17 mA/cm2 and FF = 0.66. The Se evaporation temperature is an important parameter in thin film deposition regardless of the deposition technique being used to deposit thin films

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 추계학술대회 논문집 전기물성,응용부문
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• pp.87-89
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• 2005

$Bi_{3.25}Y_{0.75}Ti_{3}O_{12}$[BYT] ferroelectric thin films were deposited by RF-Sputtering method on the $Pt/Ti/SiO_2/Si$. We investigated the effects of processing condition (especially post-annealing) on the structural and ferroelectric properties of the BYT thin films. Increasing the annealing temperature, the peak intensity of (117) increased and c-axis orientation decreased. The BYT thin films crystallized well at $600^{\circ}C$ for 30min. No secondary phases observed in the XRD pattern. At annealing temperature of $700^{\circ}C$, the thin films had no cracks and the grain was uniform. The calculated lattice constants of BYT thin films were a=0.539nm, b=0.536nm, c=3.288nm. The remnant polarization of the $Bi_{3.25}Y_{0.75}Ti_{3}O_{12}$ capacitor reached $1.8uC/cm^2$ at an applied field about 400kV/cm. The BYT thin films can be used as capacitors in Ferroelectric Random Access Memory device.

• Asian-Australasian Journal of Animal Sciences
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• 제18권5호
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• pp.711-715
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• 2005

One of the prerequisites for the successful implementation of industrial-scale goat kefir production is to understand the effects of different kefir grains and culture conditions on the microbial and chemical properties of the goat kefir. Thus, the objectives of the present study were to evaluate the characteristics of kefir grains in Taiwan on the microbial and chemical properties of goat milk kefir, as well as to understand the influence of culture conditions on production of medium chain-length triglycerides (MCT). Kefir grains were collected from households in northern Taiwan. Heat-treated goat milk was inoculated with 3-5% (V/W) kefir grains incubated at 15, 17.5, 20 or 22.5$^{\circ}C$ for 20 h, and the microflora count, ethanol content, and caproic (C6), caprylic (C8), and capric acid (C10) levels measured at 4 h intervals. Our results indicate that incubation with kefir grains results in 10$^6$-10$^7$ CFU/ml microflora count and 1.18 g/L of ethanol content at 20 h of fermentation. Incubation with 5% kefir grain at 20-22.5$^{\circ}C$ produces the highest MCT levels.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 춘계학술대회 논문집 유기절연재료 전자세라믹 방전플라즈마 일렉트렛트 및 응용기술
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• pp.79-82
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• 2002

$(Ba_{0.6-x}Sr_{0.4}Ca_x)TiO_3$ + ywt% MgO (x=0.10, 0.15, 0.20, y=0.0~3.0) ceramics were fabricated by the conventional solid-state reaction, and their structural and dielectric properties were investigated with variation of composition ratio and MgO doping content. A second phase, representative of MgO, appears in 3wt% MgO-doped BSCT specimens. Average grain sizes decreased with increasing amounts of MgO, and the BSCT(40/40/20) specimens doped with 3wt% MgO showed a value of $9.3{\mu}m$. The Curie temperature and relative dielectric constant at room temperature were decreased with increasing MgO doping content and Ca composition ratio. The relative dielectric constant was non-linearly decreased as the field strength is increased. The tunability was increased with decreasing a Ca content and the BSCT(50/40/10) specimen doped with 1.0wt% MgO content showed the highest value of 6.4% at 5kV/cm.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 추계학술대회 논문집 Vol.18
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• pp.340-341
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• 2005

Lithium titanium oxide as anode material for energy storage prepared by novel synthesis method. $Li_4Ti_5O_{12}$ based spinel-framework structures are of great interest material for lithium-ion batteries. We describe here $Li_4Ti_5O_{12}$ a zero-strain insertion material was prepared by novel sol-gel method and by high energy ball milling (HEBM) of precursor to from nanocrystalline phases. According to the X-ray diffraction and scanning electron microscopy analysis, uniformly distributed $Li_4Ti_5O_{12}$ particles with grain sizes of 100nm were synthesized. Lithium cells, consisting of $Li_4Ti_5O_{12}$ anode and lithium cathode showed the 173 mAh/g in the range of 1.0 $\sim$ 3.0 V. Furthermore, the crystalline structure of $Li_4Ti_5O_{12}$ didn't transfer during the lithium intercalation and deintercalation process.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
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• pp.589-589
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• 2012

Indium sulfide thin films have been grown onto glass substrates using radio frequency magnetron sputtering at room temperature. The as-deposited film were annealed in nitrogen atmosphere at different temperatures of 100, 200, 300, 400 and $500^{\circ}C$ with an 1 h annealing time. The effect of annealing temperature on composition, structure, morphology and optical properties of the as-grown In2S3 films has been studied. The XRD results indicate that the as-deposited films are composed by a mixture of both cubic ${\alpha}$ and ${\beta}$ crystalline phases, with some fraction of tetragonal phase. The thermal annealing on the films produces the conversion of the cubic crystalline phases to the tetragonal ${\beta}$ one and a crystalline reorientation of the latter phase. The surface morphological analysis reveals that the films grown at $300^{\circ}C$ have an average grain size of ~ 58 nm. These films show a S/In ratio of 0.99. The optical band gap is found to be direct and the films grown at $300^{\circ}C$ shows a higher optical transmittance of 80% and an energy band gap of 2.52 eV.

• Nuclear Engineering and Technology
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• 제33권6호
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• pp.626-637
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• 2001

A series of study on energy dependence in chemiluminescence dosimetry with sugar and sorbite produced in two different countries was carried out administering a dose of 5 Gy to the samples at six different mean photon energies of 30, 50, 80, 130, 662 and 1250 keV. The results revealed distinct energy dependence of chemiluminescence(CL) output of sugar and sorbite. Although the energy dependence, in general, could be fitted by a polynomial of (os E, with I being radiation energy, up to cubic term, we reached a conclusion that the adoption of a fitting function, $y_{R}$$^{=a}$.(1-e $^{-b.logE}$)$^{c}$ +d, deduced from theoretical energy response curve calculated as the ratio of the mass energy absorption of the samples of interest to the soft tissue is more reasonable and rational. Herecoefficients $y_{R}$ is CL intensity, and a, b, c and d are constants to be determined in the fitting process. Energy dependence of relative sensitivities of one sample to the other, discrepancy in sensitivities of the samples from the two countries, and prominent grain size effect in Sorbitol were also shown.shown.

• Journal of Electrochemical Science and Technology
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• 제2권3호
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• pp.168-173
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• 2011

The availability, low toxicity, and high degree of technological development make silicon the most likely material to be used in solar cells, the cost of solar cells depends entirely on cost of high purity silicon production. The present work was conducted to electrodeposite of silicon from $K_2SiF_6$, an inexpensive raw material prepared from fluorosilicic acid ($H_2SiF_6$) produced in Iraqi Fertilizer plants, and using inexpensive graphite material as cathode electrode. The preparation of potassium fluorosilicate was performed at ($60^{\circ}C$) in a three necks flask provided with a stirrer, while the electro deposition was performed at $750^{\circ}C$ in a three-electrodes configuration with melt containing in graphite pot. High purity potassium fluorosilicate (99.25%) was obtained at temperature ($60^{\circ}C$), molar ratio-KCl/$H_2SiF_6$(1.4) and agitation (600 rpm). Spongy compact deposits were obtained for silicon with purity not less than (99.97%) at cathode potential (-0.8 V vs. Pt), $K_2SiF_6$ concentration (14% mole percent) with grain size (130 ${\mu}m$) and level of impurities (Cu, Fe and Ni) less than (0.02%).