Effects of dopant (Al, Ga, and In) on the characteristics of ZnO thin films prepared by RF magnetron sputtering system

Kyu Ung Sim,신승욱,A.V. Moholkar,문종하,Jae Ho Yun,김진혁 한국물리학회 2010 Current Applied Physics Vol.10 No.3

The un-doped and Al, Ga, and In doped (3 wt.%) ZnO thin films have been prepared on glass substrates using RF magnetron sputtering at 350 ℃. The effects of these dopants on the structural, morphological,electrical, and optical properties of deposited films have been studied. XRD study showed that all doped ZnO thin films have the polycrystalline nature with hexagonal wurtzite phase having c-axis preferred out-of-plane orientation. The cross-sectional FE-SEM micrographs showed that all the films have columnar structure. AFM images showed that doped ZnO thin films have better surface smoothness than undoped ZnO thin films regardless of doping elements. The GZO thin film have the optimal electrical properties among all doped samples in terms of the carrier concentration (6.13 × 1023 cm-3), charge carrier mobility (28.2 ㎠ V-1 s-1), and a minimum resistivity (3.61 × 10-4 Ω cm). UV–Vis spectrometer results showed that all the films are highly transparent in the visible region and the band gap energy of the films varies from 3.25 eV to 3.75 eV for the different dopants. PL spectra showed the un-doped and doped ZnO thin film exhibited a violet emission in the 390–405 nm range, with different intensities, which is due to difference in concentration of zinc vacancies.

Chromium oxide supported on Zr modified alumina for stable and selective propane dehydrogenation in oxygen free moving bed process

Sim, Seohyun,Gong, Sujin,Bae, Jongyoon,Park, Yong-Ki,Kim, Jongwoo,Choi, Won Choon,Hong, Ung Gi,Park, Deuk Soo,Song, In Kyu,Seo, Hwimin,Kang, Na Young,Park, Sunyoung Elsevier 2017 Molecular catalysis Vol.436 No.-

<P>Propane dehydrogenation in oxygen free environment over alumina-supported chromium oxide catalysts with different chromium loading was studied within short time-on-stream range for the fluidized moving bed applications. For this purpose, a series of CrOx/Al2O3 and CrOxar-Al2O3 catalysts were prepared and examined. Increase in the chromium loading resulted in reduction of monochromate species, possibly leading to formation of polychromate species. Further increase of chromium loading led to formation of Cr2O3 species. Accordingly, specific activity of the catalyst decreased with increasing chromium loading. Propane conversion significantly decreased and propylene selectivity increased during an induction period due to the rapid consumption of limited lattice oxygen in the catalyst. Equilibrated and artificially aged catalysts were characterized in order to investigate the factors affecting propylene selectivity and catalyst durability by pore analysis, temperature-programmed reduction (H-2-TPR), temperature programmed desorption (NH3-TPD), X-ray diffraction patterns (XRD), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS). After an artificial catalyst aging treatment, all catalysts showed reduction in catalytic activity and the most drastic activity decrease was found in the catalyst with the highest loading of 20 wt% Crhi-Al2O3 sample. The activity loss was mainly due to agglomeration of the chromium species, reduction of the surface area, and transformation of Cr6+ species into stable Cr2O3 species. Cr species were agglomerated on the surface of alumina support during the aging treatment and the agglomeration was more pronounced at the high Cr loading. Moreover, Raman spectroscopy and XRD analyses revealed the formation of chromia/alumina solid solution in the catalyst after the aging treatment which also significantly contributed to the activity loss. Contrarily, Zr modified alumina support successfully suppressed the formation of chromia/alumina solid solution phase and substantially improved the catalytic activity after the aging treatment by increasing the dispersion of chromium oxide. Zr-Al2O3 support showed lower catalytic activity toward propylene than Al2O3 support, which also contributed to the higher propylene yield of Cr/Zr-Al2O3. (C) 2017 Published by Elsevier B.V.</P>

The effect of processing parameters on the properties of Ga-doped ZnO thin films by RF magnetron sputtering

신승욱,Kyu Ung Sim,문종하,김진혁 한국물리학회 2010 Current Applied Physics Vol.10 No.2

The 3 wt% Ga-doped ZnO (GZO) thin films were prepared on glass substrates by RF magnetron sputtering with different processing parameters such as RF powers, substrate temperatures and Ar working pressures. Crystallinity and electrical properties of GZO films were investigated. The X-ray diffraction results showed that all the GZO films were grown as a hexagonal wurtzite phase with highly c-axis preferred out-of-plane orientation. The electrical properties of GZO films were strongly related to processing parameters. With increasing the processing parameter values, the electrical properties of GZO films were improved up to at 350 ℃, 200Wand 6 mTorr, above that they became worse at 400 ℃ and 7.5 mTorr. The film showed the lowest resistivity of 3.45 × 10-4 Ωcm when the film was prepared in the optimized conditions of processing parameters of 350 ℃, 6 mTorr, and 200 W.

연구논문 : 곤약의 최적 응고 및 항미생물 활성을 위한 조건 확립

심재인 ( Jae In Sim ),최선정 ( Seon Jeong Choi ),정재현 ( Jae Hyun Jeong ),최웅규 ( Ung Kyu Choi ) 한국식생활문화학회 2014 韓國食生活文化學會誌 Vol.29 No.5

This study was conducted to establish optimum conditions for coagulation of konjac jelly as well as antimicrobial activity by concentration of Ca(OH)2. Hardness, gumminess, and chewiness of konjac jelly increased according to concentration of konjac powder. A Ca(OH)2 concentration of 0.4-0.6% as a coagulation agent was optimum for coagulation of konjac jelly. Further, sensory score was highest at a Ca(OH)2 concentration of 0.6%. All populations of bacteria, yeast, and mold in konjac jelly were restrained by Ca(OH)2 concentration-dependent manner. Furthermore all tested microoraganisms were strictly restrained at 1.0x10-2 N of Ca(OH)2.

Optimization of Aqueous Nano Ceramic Ink and Printing Characterization for Digital Ink-Jet Printing

Kwon, Jong-Woo,Sim, Hee-Seok,Lee, Jong-Heun,Hwang, Kwang-Taek,Han, Kyu-Sung,Kim, Jin-Ho,Kim, Ung-Soo The Korean Ceramic Society 2017 한국세라믹학회지 Vol.54 No.6

The advantage of ceramic ink-jet printing technology is the accurate and fast printing process of digital images for various products. For digital ink-jet printing applications, ceramic ink requires proper viscosity and surface tension, along with dispersion stability of the inorganic pigments. The purpose of this study is the formulation of an environment-friendly ceramic ink with a water-based system; using nano-sized $CoAl_2O_4$ pigment as a raw material, ink should have dispersion stability to prevent nozzle clogging during ink-jet printing process. In addition, the surface tension of the ceramic ink was optimized with the polysiloxane surfactant according to the surface tension requirement (20 - 45 mN/m) for ceramic ink-jet printing; by adjusting the viscosity with poly ethylene oxide, jetting behavior of the ceramic ink was investigated according to changes in the physical features through drop watcher measurement.

곤약 가공을 위한 응고제 선정 및 식중독균에 대한 항균 활성 확인

심재인,최선정,정재현,최웅규,Sim, Jae-In,Choi, Seon-Jeong,Jeong, Jae-Hyun,Choi, Ung-Kyu 한국식품영양학회 2014 韓國食品營養學會誌 Vol.27 No.4

본 연구에서는 곤약 가공을 위한 응고제와 침지액을 선정하고, 침지액 농도에 따른 식중독균에 대한 항균 활성을 확인하였다. 응고제 종류에 따른 곤약의 응고시간별 물성 변화는 응고액의 종류에 관계없이 응고시간이 진행될수록 경도, 검성 및 씹힘성이 증가하였다. 응고제 종류에 따른 곤약의 무기질 함량은 응고제가 $Ca(OH)_2$일 경우, NaOH를 이용한 곤약보다 유의적으로 높은 Ca 함량을 나타내었으며, 응고제가 NaOH일 경우에는 $Ca(OH)_2$보다 유의적으로 높은 Na 함량을 나타내었다. Mg와 P의 경우에는 응고제의 종류에 따른 유의적 차이는 보이지 않았다. 관능검사에서 색, 향, 맛, 조직감 및 전반적인 기호도는 응고제의 종류에 따른 유의적 차이는 없었다. 곤약의 제조과정 중 식중독균인 Staphylococcus aureus, E. coli, Salmonella typhimurium을 접종하여 $Ca(OH)_2$ 농도에 따른 항균 활성을 본 결과, $1.0{\times}10^{-4}N$ 용액에 저장한 곤약이 가장 항균 활성이 적었으며, $1.0{\times}10^{-2}N$ 농도가 가장 항균 활성이 높았다. 즉, 응고액의 농도에 비례하여 균 성장이 억제됨을 확인할 수 있었다. 제조 공정 별 미생물 변화는 구약감자 분말을 입고하여 저장시켰을 때 미생물 수가 약간 증가하지만, 그 이후 공정부터는 미생물 수가 급격하게 감소되며, 성형 이후부터는 검출되지 않는 것으로 확인되었다. This study was conducted to select the coagulant for konjac processing and to identify the antibacterial activity on foodborn pathogens by concentration of $Ca(OH)_2$. In rheological properties such as hardness, gumminess and chewiness, konjac jelly were increased by progressing coagulation regardless of coagulant. In mineral contents, the Ca content of konjac jelly made with $Ca(OH)_2$ was significantly higher than that of NaOH. On the contrary, the Na content of konjac jelly made with NaOH coagulant was significantly higher than that of $Ca(OH)_2$. There were no significant differences in the Mg and P contents according to coagulant. In sensory evaluation, there were no significant differences in the color, flavor, taste, texture and overall quality according to coagulant. The antimicrobial activities of Staphylococcus aureus, E. coli, Salmonella typhimurium were inhibited in proportion to the concentration of $Ca(OH)_2$. According to the manufacturing process of konjac jelly, the change in microorganism was not found after molding.

론문(論文) : 맥상(脈狀)의 환측(患側) 취혈(取穴)과 침(鍼) 치료(治療)경과 확인 기준으로서의 촌구맥진(寸口脈診)의 의의(意義)

심소현 ( So Hyun Sim ),강민정 ( Min Jung Kang ),김재규 ( Jae Kyu Kim ),백진웅 ( Jin Ung Baek ) 대한한의학원전학회(구 대한원전의사학회) 2014 대한한의학원전학회지 Vol.27 No.1

Objective : The aim of this study is to find out the significance of Chongu pulse diagnosis as the standard of measuring the result of the acupuncture on ‘the affected part of the pulse wave’ based on the literature. Method : ① The clear concepts of the ‘unaffected part’ and the ‘affected part’ were organized. ② The relation between the pulse diagnosis and the acupuncture in Hwangjenaekyung was studied. ③ The indications of Mu acupuncture treatment(繆刺法) and Geo acupuncture treatment(巨刺法) in Hwangjenaekyung was studied. ④ The types and changes of pulse diagnosis in Hwangjenaekyung was studied, especially based on the relation between Sambuguhu pulse diagnosis(三部九候脈診) and Chongu pulse diagnosis(寸口脈診). ⑤ By synthesizing these results, the significance of Chongu pulse diagnosis as the standard of measuring the result of the acupuncture on ‘the affected part of the pulse wave’ was found. Result & Conclusion : 1. When the affected part and the unaffected part are defined, it is necessary to make clear that which one of next three definitions is used ; Firstly, ‘the broad sense of definition of the affected part and the unaffected part of the symptom’, which contains the pulse wave. Secondly, ‘the narrow sense of definition of the affected part and the unaffected part of the symptom’, without the pulse wave. And thirdly, ‘the definition of the affected and the unaffected part of the pulse wave’, which has the only independent standard of the pulse wave. 2. Geo acupuncture treatment(巨刺法) is an acupuncture treatment which means the needling on ‘the affected part of the pulse wave’ based on Sambuguhu pulse diagnosis (三部九候脈診), and Mu acupuncture treatment(繆刺法) is an acupuncture treatment which means the needling on ‘the unaffected part of the symptom based on the narrow sense of the definition’. The range of the indications of Mu acupuncture treatment(繆刺法) and Geo acupuncture treatment(巨刺法) contains most of the diseases which contains Rakbyung(絡病), Kyungbyung(經病) and Ojangbyung(五臟病). 3. Chongu pulse diagnosis(寸口脈診) contains not only the range of the indications of Sambuguhu pulse diagnosis(三部九候脈診), but also most of the diseases. 4. From synthesizing these results of the study on the literature, we infer that Chongu pulse diagnosis as the standard of measuring the result of the acupuncture on ‘the affected part of the pulse wave’ is significant.