• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.30 no.6
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• pp.387-392
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• 2017

A high-performing all-transparent photodetector was created by configuring a $MoO_x$/NiO/ZnO/ITO structure on a glass substrate. The ITO bottom layer was applied as a back contact. To achieve the transparent p/n junction, p-type NiO was coated on the n-type ZnO layer. Reactive sputtering was used to spontaneously form the ZnO or NiO layer. In order to improve the transparent photodetector performance, the functional $MoO_x$ window layer was used. Optically, the $MoO_x$ window provided a refractive index layer (n=1.39) lower than that of NiO (n=2), increasing the absorption of the incident light wavelengths (${\lambda}s$). Moreover, the $MoO_x$ window can provide a lower sheet resistance to improve the carrier collection for the photoresponses. The $MoO_x$/NiO/ZnO/ITO device showed significantly better photoresponses of 877.05 (at ${\lambda}$=460nm), 87.30 (${\lambda}$=520 nm), and 30.38 (${\lambda}$=620 nm), compared to 197.28 (${\lambda}$=460 nm), 51.74 (${\lambda}$=520 nm) and 25.30 (${\lambda}$=620 nm) of the NiO/ZnO/ITO device. We demonstrated the high-performing transparent photodetector by using the multifunctional $MoO_x$ window layer.

• Journal of radiological science and technology
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• v.41 no.5
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• pp.413-419
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• 2018

Magnetic Resonance Imaging for patients with metallic implant has poor image quality, and signal loss and artifacts including distortion can occur. The purpose of this study is to carry out a comparative evaluation on high receive bandwidth(hiBW), O-MAR, O-MAR XD to reduce artifacts in knee implant. To take MRI, 3.0T scanner and dual-source radiofrequency transmission were used. O-MAR XD technique's strong option showed a significant difference (p<0.001) with O-MAR XD technique's weak option, O-MAR and hiBW excluding the medium option. O-MAR XD's medium option had a significant difference (p<0.01) with O-MAR XD's weak, O-MAR and hiBW. O-MAR XD technique's weak option had a significant difference (p<0.01) with O-MAR XD's strong and medium options, O-MAR and hiBW. O-MAR technique had a significant difference (p<0.001) with strong, medium, weak options of O-MAR XD technique except for hiBW. HiBW had a significant difference (p<0.001) with strong, medium and weak options of O-MAR XD technique except for O-MAR. The results showed that O-MAR XD technique was more useful for MRI scan for patients with knee replacement surgery than traditional techniques such as hiBW or O-MAR, and susceptibility artifacts decreased more when O-MAR XD technique's strong or medium option was applied. Based on the results above, it is considered that it will be possible to acquire images whose susceptibility artifacts were highly decreased by using O-MAR XD technique's strong or medium option when conducting MRI for artificial knee joint and it will be helpful for checking and monitoring patients with knee joint replacement.

• Journal of the Institute of Electronics Engineers of Korea TE
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• v.39 no.1
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• pp.1-8
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• 2002

The effects of the addition of either monoclinic $ZrO_2$($ZrO_2$(m)) or tetragonal $ZrO_2$($ZrO_2$(t)) containing 5.35wt% $Y_2O_3$ on the physical properties and electrical conductivity of TEX>$Al_2O_3$ were investigated. The addition of $ZrO_2$(m) and $ZrO_2$(t) increased sintered density of $Al_2O_3$. The Vickers hardness also increased as addition of >($ZrO_2$(t) increased going through a maximum at 20wt% and the hardness of the specimens was found to be dependent on the sintered density. The addition of $ZrO_2$(t) improved the hardness of $Al_2O_3$-$ZrO_2$ systems and the $ZrO_2$(m) addition showed the better effect on the thermal shock property of $Al_2O_3$-$ZrO_2$ systems than that of the $ZrO_2$(t) addition. Above 15wt% addition of $ZrO_2$(t), the electrical conductivity is gradually increased with increasing applied voltage but not effects by addition of $ZrO_2$(m).

• Korean Journal of Materials Research
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• v.5 no.7
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• pp.897-902
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• 1995

To get optimum synthetic condition of zeolite A made from Kampo natural bentonite, the effects of reactant mole fraction, reaction temperature, and reaction time were studied. The source of silica was 40% -H₂SO₄ treated natural bentonite and that of alumina was synthesized NaA1O₂. The reactant was mixed at the mole ratio of SiO₂ : Al₂O₃ : Na₂O : H₂O=2 : 1 : 1 : 25 and 2 : : 1 : 37. The mixed reactants were aged at 60℃ for 1hr and reacted at 90℃, 100℃ and 120℃ for 1, 3 and 5hr. The optimum synthetic condition was SiO₂ : A1₂O₃ : Na₂O H₂O=2 : 1 : 1 : 30 at 90℃ for 3hr and the synthetic zeolite A prepared by this optimum condition showed the dehydration temperature at 79.2℃ and lattice trans-formation at 503.3℃. The wright loss of water was 5.9%.

• 중국학논총
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• no.63
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• pp.29-45
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• 2019

现代汉语普通话中单元音'o'在不同韵母中的音值有差别, 但对此专家议论纷纷, 对学汉语的学生, 教汉语的老师是个难点之一. 本论文对'o'的音值和与'o'结合的二合复元韵母, 三合复元韵母进行考察, 寻找不同韵母中的'o'的正确的音值. 本论文把韩国教材里的关于'o'的说明进行分析, 再对中国学者的解释进行对照检查. 分析调查结果说明, 'o'是不同韵母中的音值不一样, 单元音'o'的实际音值是[o]和[ɔ]之间, 'ou'和'iou'的'o'的实际音值可以说是[o]或[ə]. 对于'ou', 'iou', 'uo'的'o'的音值, 有的韩国学者主张跟韩国语中[오]比较接近, 还有的学者主张跟韩国语中[어]更接近. 本论文还对怎样教好韵母'o'的发音提出方案.

• Journal of the Korean Ceramic Society
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• v.25 no.1
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• pp.35-41
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• 1988

In the system of Li2O-MgO-Al2O3-Cr2O3, the crystalline solid solution of LiCrO2 along the pseudo-binary join between rocksalt structure(LiCrO2) and spinel structure(MgCr2O4 or MgAl2O4) have been investigated by x-ray diffraction techniques. In this study, order-disorder phase transition of LiCrO2 was observed and the unit cell of the disordered LiCrO2 structure has been established. It has been found that LiCrO2 makes a solid solution over a wide range with MgAl2O4, while not with MgCr2O4. This difference was explained as being due to the ability of oxygen lattice distortion which depended on the relative sizes and chemical bonding characteristics of the substituted ions.

• Fashion & Textile Research Journal
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• v.20 no.6
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• pp.645-655
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• 2018

Online to Offline(O2O), a new model of e-commerce, has been gradually recognized and accepted by consumers. Electronic commerce has become diversified and O2O marketing is the new trend of e-commerce. The rapid popularization of mobile Internet and online shopping makes O2O service gets more attention. Although recently O2O service and O2O marketing get much attention, there is no much preceding research about the antecedents of mobile shopping of O2O market. The purpose of the study is to examine the effect of shopping orientation on intention to reuse O2O services and the moderating effect of impulse buying tendency. A total of 209 surveys were collected online in total for the data of the study. The key findings of this study are as follows: First, convenience seeking shopping orientation has a positive effect on the intention to reuse O2O service and brand seeking shopping orientation has, too. Second, impulse buying tendency positively moderated the relationship between hedonic seeking shopping orientation and intention to reuse O2O service, and negatively moderated sales seeking shopping orientation and intention to reuse O2O service. The results of this study presented some implications for operators at O2O service area. Research findings and study limitations are discussed.

• Journal of Powder Materials
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• v.21 no.5
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• pp.360-365
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• 2014

$SnO_2-CoO$/carbon-coated CoO core/shell nanowire composites were synthesized by using electrospinning and hydrothermal methods. In order to obtain $SnO_2-CoO$/carbon-coated CoO core/shell nanowire composites, $SnO_2-Co_3O_4$ nanowire composites and $SnO_2-Co_3O_4$/polygonal $Co_3O_4$ core/shell nanowire composites are also synthesized. To demonstrate their structural, chemical bonding, and morphological properties, field-emission scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy were carried out. These results indicated that the morphologies and structures of the samples were changed from $SnO_2-Co_3O_4$ nanowires having cylindrical structures to $SnO_2-Co_3O_4/Co_3O_4$ core/shell nanowires having polygonal structures after a hydrothermal process. At last, $SnO_2-CoO$/carbon-coated CoO core/shell nanowire composites having irregular and high surface area are formed after carbon coating using a polypyrrole (PPy). Also, there occur phases transformation of cobalt phases from $Co_3O_4$ to CoO during carbon coating using a PPy under a argon atmosphere.

• Korean Journal of Materials Research
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• v.18 no.7
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• pp.389-393
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• 2008

Nano-sized $TiO_2$-60 wt% SrO composite powders were synthesized by a sol-gel method using titanium isopropoxide and $Sr(OH)_2\;{\cdot}\;8H_2O$ as precursors. 3, -5, -7 wt%Ag spot-coated $TiO_2$-60 wt% SrO composite powders were synthesized by a Ag electroless deposition method using $TiO_2$-60 wt% SrO composite powders calcined at $1050^{\circ}C$, which mainly exhibited the $SrTiO_3$phase. However, a small number of rutile $TiO_2$, $Sr_2TiO_4$ and $SrO_2$ phases were also detected. In the Ag spot-coated powders synthesized by electroless deposition, nano-sized particles about 5-25 nm in diameter adhered to the $TiO_2$-60 wt% SrO composite powders. The photocatalytic activity of Ag spot-coated $TiO_2$-SrO and $TiO_2$-SrO composite powders for degradation of phenol showed that all of $TiO_2$-SrO composite powders were highly active under UV light irradiation. 7 wt%Ag spot-coated $TiO_2$-60wt.%SrO composite powders had a relatively higher photocatalytic activity than did $TiO_2$-SrO composite powders under visible light.

• Bulletin of the Korean Chemical Society
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• v.18 no.8
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• pp.831-840
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• 1997

Core/shell structured composite metal oxides of Fe2O3/MgO were prepared by thermal decomposition of Fe(acac)3 adsorbed on the surface of MgO cores. The morphology of the composites conformed to that of the MgO used as the cores. Broad powder X-ray diffraction peaks shifted toward larger d, large BET surface area (∼350 m2/g), and the size of crystalline domains in nano range (4 nm), all corroborate to the nanocrystallinity of the Fe2O3/MgO composite which was prepared by using nanocrystalline MgO as the core. By use of microcrystalline MgO as the core, microcrystalline Fe2O3/MgO composite was prepared, and it had small BET surface area of less than 35 m2/g. AFM measurements on nanocrystalline Fe2O3/MgO showed a collection of spherical aggregates (∼80 nm dia) with a very rough surface. On the contrary, microcrystalline Fe2O3/MgO was a collection of plate-like flat crystallites with a smooth surface. The nitrogen adsorption-desorption behavior indicated that microcrystalline Fe2O3/MgO was nonporous, whereas nanocrystalline Fe2O3/MgO was mesoporous. Bimodal distribution of the pore size became unimodal as the layer of Fe2O3 was applied to nanocrystalline MgO. The macropores in a wide distribution which the nanocrystalline MgO had were absent in the nanocrystalline Fe2O3/MgO. The decomposition of CCl4 was largily enhanced by the overlayer of Fe2O3 on nanocrystalline MgO making the reaction between nanocrystalline Fe2O3/MgO and CCl4 be nearly stoichiometric. The reaction products were environmentally benign MgCl2 and CO2. Such an enhancement was not attainable with the microcrystalline samples. Even for the nanocrystalline MgO, the enhancement was not attained, if not with the Fe2O3 layer. Without the layer of Fe2O3, it was observed that the nanocrystalline domain of the MgO transformed into microcrystalline one as the decomposition of CCl4 proceeded on its surface. It appeared that the layer of Fe2O3 on the particles of nanocrystalline Fe2O3/MgO blocked the transformation of the nanocrystalline domain into microcrystalline one. Therefore, in order to attain stoichiometric reaction between CCl4 and Fe2O3/MgO core/shell structured composite metal oxide, the morphology of the core MgO has to be nanocrystalline, and also the nanocrystalline domains has to be sustained until the core was exhausted into MgCl2.