• 분석과학
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• 제15권3호
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• pp.256-262
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• 2002

평균입자크기가 200 ${\mu}m$인 코디어라이트 분말을 사용하여 다공성 필터를 제조한 후, 진공함침법으로 $V_2O_5$, CuO, $LaCoO_3$ 촉매를 담지시킨 후 NO와 $SO_2$ 기체를 촉매 담지 세라믹필터에 동시 통과시키면서 NOx/SOx의 동시제거효율을 측정하였다. 제조된 다공성 필터의 기공률은 61.6%였고, 압축강도는 12.3 MPa이었으며, 면속도 5 cm/sec에서의 차압은 147 Pa이었다. NO와 $SO_2$의 동시제거효율을 분석해 본 결과, 페로브스카이트계 $LaCoO_3$ 촉매의 동시제거효율이 가장 우수함을 확인하였으며, $LaCoO_3$ 촉매의 NO에 대한 제거효율은 90% 이상, $SO_2$에 대해서는 80% 이상이었다.

• 한국재료학회지
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• 제23권11호
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• pp.613-619
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• 2013

$Cu_2ZnSn(S_x,Se_{1-x})_4$ (CZTSSe) thin films were prepared by sulfurization of evaporated precursor thin films. Precursor was prepared using evaporation method at room temperature. The sulfurization was carried out in a graphite box with S powder at different temperatures. The temperatures were varied in a four step process from $520^{\circ}C$ to $580^{\circ}C$. The effects of the sulfurization temperature on the micro-structural, morphological, and compositional properties of the CZTSSe thin films were investigated using X-ray diffraction (XRD), Raman spectra, field emission scanning electron microscopy (FE-SEM), and transmission electron microscopy (TEM). The XRD and Raman results showed that the sulfurized thin films had a single kesterite crystal CZTSSe. From the FE-SEM and TEM results, the $Mo(S_x,Se_{1-x})_2$ (MoSSe) interfacial layers of the sulfurized CZTS thin films were observed and their thickness was seen to increase with increasing sulfurization temperature. The microstructures of the CZTSSe thin films were strongly related to the sulfurization temperatures. The voids in the CZTSSe thin films increased with the increasing sulfurization temperature.

• 한방안이비인후피부과학회지
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• 제30권3호
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• pp.220-230
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• 2017

Objectives : The purpose of this study is to report the efficacy of using oriental medical treatment with Melonix Calyx Vomiting Therapy for Cholinergic urticaria patient. Methods : We experienced one case of Cholinergic urticaria patient treated with oriental medical treatment and Melonix Calyx Vomiting Therapy(MCVT). MCVT is traditional treatment, which induces vomiting by eating Melonix Calyx powder with water. To evaluate the results of this treatment, we measured the decrease of pruritus, number of wheals, redness. Decrease of pruritus, number of wheals was assessed by Urticaria Activity Score(UAS) and quality of life was assessed by Chronic urticaria quality of life questionnaire(CU-Q2oL). Results : UAS decreased from 6 to 0, and severity score of redness decreased from 3 to 0. CU-Q2oL score decreased from 78 to 23. Conclusions : This study suggests that using MCVT with oriental medical treatment is effective on Cholinergic urticaria.

• 자원리싸이클링
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• 제6권3호
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• pp.28-35
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• 1997

조개껍질(굴, 고막)을 수처리재로 활용하기 위한 기초 실험으로 중금속(Cd, Cu, Fe, Mn, Pb, Zn)과 유기성분(TCE(Trichlo-roethylene)와 PCE(Tetrachroethylene))의 흡착능을 조사했다. 수산화칼슘으로 이루어진 굴과 고막껍질의 소성 분말 주입에 따른 중금속 제거효율은 Mn, Zn, Fe, Cd, Cu, Pb의 순이었다. 우수한 중금속 흡착능은 조개껍질의 $Ca(OH)_2$ 성분에 의한 높은 pH유지에 따른 중금속 탄산염과 수산화물의 형성에 의한 침전작용, 조개껍질의 칼슘 매트릭스 구조에 의한 중금속의 고정화와 잔존하는 불용성 유기물의 결합 등의 작용이라고 본다. 이와 같은 굴껍질은 침출수의 중화작용과 동시에 우수한 중금속 흡착능을 가지고 있어, 이것을 수처리로 활용될 경우, 저렴한 재료의 확보와 더욱이 부가가치가 높은 폐부산자원을 활용한 정화용 세라믹스 담체의 개발로 폐부산자원 폐기처리 문제 이외의 환경정화용 세라믹스 및 담체 등의 환경분야 사업으로 확장 발전시킬 수 있다고 본다.

• 대한금속재료학회지
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• 제50권9호
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• pp.677-684
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• 2012

A feasible way to fabricate in-situ Al/TiC composites was investigated. An elemental mixture of $Al-TiO_2-C$ pellet was directly added into an Al melt at $800-920^{\circ}C$ to form TiC by self-combustion reaction. The addition of CuO initiates the self-combustion reaction to form TiC in $1-2{\mu}m$ at the melt temperature above $850^{\circ}C$. Besides the CuO addition, a diluent element of excess Al plays a significant role in the TiC formation by forming a precursor phase, $Al_3Ti$. Processing parameters such as CuO content, the amount of excess Al and the melt temperature, have affected the combustion reaction and formation of TiC, and their influences on the microstructures of in-situ Al/TiC composites are examined.

• 한국재료학회지
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• 제29권9호
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• pp.553-558
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• 2019

$Cu_2ZnSn(S,Se)_4(CZTSSe)$ thin film solar cells areone of the most promising candidates for photovoltaic devices due to their earth-abundant composition, high absorption coefficient and appropriate band gap. The sputtering process is the main challenge to achieving high efficiency of CZTSSe solar cells for industrialization. In this study, we fabricated CZTSSe absorbers on Mo coated soda lime glass using different pressures during the annealing process. As an environmental strategy, the annealing process is performed with S and Se powder, without any toxic $H_2Se$ and/or $H_2S$ gases. Because CZTSSe thin films have a very narrow stable phase region, it is important to control the condition of the annealing process to achieve high efficiency of the solar cell. To identify the effect of process pressure during the sulfo-selenization, we experiment with varying initial pressure from 600 Torr to 800 Torr. We fabricate a CZTSSe thin film solar cell with 8.24 % efficiency, with 435 mV for open circuit voltage($V_{OC}$) and $36.98mA/cm^2$ for short circuit current density($J_{SC}$), under a highest process pressure of 800 Torr.

• 한국분말재료학회지
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• 제16권1호
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• pp.22-27
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• 2009

To improve the filtration efficiency of porous materials used in filters, an extensive specific surface area is required to serve as a site for adsorption of impurities. In this paper, a method for creating a hybridized porous alloy using a powder metallurgical technique to build macropores in an Al-4 wt.% Cu alloy and subsequent surface modification for a microporous surface with a considerably increased specific surface area is suggested. The macropore structure was controlled by granulation, compacting pressure, and sintering; the micropore structure was obtained by a surface modification using a dilute NaOH solution. The specific surface area of surface-modified specimen increased about 10 times compare to as-sintered specimen that comprised of the macropore structure. Also, the surface-modified specimens showed a remarkable increase in micropores larger than 10 nm. Such a hybridized porous structure has potential for application in water and air purification filters, as well as membrane pre-treatment and catalysis.

• 한국분말재료학회지
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• 제22권4호
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• pp.229-233
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• 2015

Porous metallic glass compact (PMGC) are developed by electro-discharge sintering (EDS) process of gas atomized $Zr_{41.2}Ti_{13.8}Cu_{12.5}Ni_{10}Be_{22.5}$ metallic glass powder under of 0.2 kJ generated by a $450{\mu}F$ capacitor being charged to 0.94 kV. Functional iron-oxides are formed and growth on the surface of PMGCs via hydrothermal synthesis. It is carried out at $150^{\circ}C$ for 48hr with distilled water of 100 mL containing Fe ions of 0.18 g/L. Consequently, two types of iron oxides with different morphology which are disc-shaped $Fe_2O_3$ and needle-shaped $Fe_3O_4$ are successfully formed on the surface of the PMGCs. This finding suggests that PMGC witih hydrothermal technique can be attractive for the practical technology as a new area of structural and functional materials. And they provide a promising road map for using the metallic glasses as a potential functional application.

• 생명과학회지
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• 제10권4호
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• pp.347-353
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• 2000

This study was designed to investigate the effects of silkworm (Bombyx mori L.) powder (SWP) on oxygen radicals and their scavenger enzymes in liver membranes of rats. Sprague-Dawley(SD) male rats(160$\pm$10g) were fed basic diet (control group), and experimental diets(SWP-200 and SWP-400 groups) added 200 and 400 mg/kg BW/day for 6 weeks. Hydroxyl radical (.OH) levels resulted in a consistent decreases (4.0% and 7.2%, 5.0% and 14.1%, respectively) in liver mitochondria and microsomes of SWP-200 SWP-400 groups compared with control group, and O2 radical level was significantly decreased about 12% in liver cytosol of SWP-400 group compared with control group. Lipid peroxide(LPO) levels were significantly decreased (14.4% and 9.1%, respectively) in liver mitochondria and microsomes of SWP-400 group only compared with control group. Oxidized protein (OP) levels were remarkably decreased about 12.7% and 16.3% in liver microsomes only of SWP-200 and SWP-400 groups, but significant difference between liver mitochondria could not obtained. Mn-SOD activities were remarkably increased (15.8% and 25.2%, respectively) in mitochondria of SWP-200 and SWP-400 groups, but significant difference between Cu, Zn-SOD activities in these group could be not obtained. GSHPx activity was significantly increased in liver cytosol of SWP-400 group compared with control group. These results suggest that silkworm powder may play an effective role in a attenuating a oxidative stress and increasing a scavenger enzyme activity in liver membranes.

• Journal of Welding and Joining
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• 제35권2호
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• pp.58-62
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• 2017

A319 aluminum alloy containing 6.5% Si and 3.5% Cu as major alloying elements has been widely used in machinery parts because of its excellent castability and crack resistance. However it needs more wear resistance to extend its usage to the severe wear environments. It has been known that hyper-eutectic Al-Si alloy having more than 12.6% Si contains pro-eutectic Si particles, which give better wear resistance and lubrication characteristics than hypo-eutectic Al-Si alloy like A319 alloy. In this study, it was tried to clad hyper-eutectic Al-Si alloy on the surface of A319 alloy. In the experiments, Al-36%Si alloy powder was mixed with organic binder to make a fluidic paste. The paste was screen-printed on the A319 alloy surface, melted by pulsed Nd:YAG laser and alloyed with the A319 base alloy. As experimental parameters, the average laser power was changed to 111 W, 202 W and 280 W. With increasing the average laser power, the melting depth was changed to $142{\mu}m$, $205{\mu}m$ and $245{\mu}m$, and the dilution rate to 67.2 %, 72.4 % and 75.7 %, and the Si content in the cladding layer to 16.2 %, 14.6 % and 13.7 %, respectively. The cross-section of the cladding layer showed very fine eutectic microstructure even though it was hyper-eutectic Al-Si alloy. This seems to be due to the rapid solidification of the melted spot by single laser pulse. The average hardness for the three cladding layers was HV175, which was much higher than HV96 of A319 base alloy. From the block-on-roll wear tests, A319 alloy had a wear loss of 5.8 mg, but the three cladding layers had an average wear loss of 3.5 mg, which meant that an increase of 40 % in wear resistance was obtained by laser cladding.