Role of the Oxidizing Agent in the Etching of 4H-SiC Substrates with Molten KOH

Moonkyong Na,In-Ho Kang,Jeong Hyun Moon,Wook Bahng 한국물리학회 2016 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.69 No.11

A novel etching solution using molten potassium hydroxide (KOH) for the identification of dislocation types in a silicon-carbide (SiC) epilayer is identified. Threading screw dislocations (TSDs) and threading edge dislocations (TEDs) are rarely useful for size-based differentiation of etch pits in highly nitrogen (N)-doped SiC through conventional KOH etching. In this study, we report the role of sodium peroxide (Na2O2) and potassium dioxide (KO2) as oxidizing agent additives to the etchant for identifying the dislocation types in highly N-doped 4H-SiC. A Na2O2-KOH phase diagram was calculated to predict the chemical composition of the etchant. Solid-phase Na2O2 remained in the system when added to the etchant at concentrations greater than 13-wt% Na2O2, and it provided excess oxygen to the etchant. We experimentally confirmed that etch pit shapes became more hexagonal and that the etch pit sizes of TSDs and TEDs differed more greatly when more than 20-wt% Na2O2 was added to the etchant. We also found that the size distribution of TEDs was much smaller than that of TSDs after etching using Na2O2-KOH. Dissolved oxygen played an essential role in enhancing the anisotropic etching of highly N-doped SiC and allowed the dislocation types to be identified.

Furosemide에 의한 소디움 운반체 발현의 변화

오윤규 ( Yoon Kyu Oh ),나기영 ( Ki Young Na ),이재욱 ( Jay Wook Lee ),장혜련 ( Hye Ryun Chang ),박영선 ( Young Sun Park ),박정환 ( Jung Hwan Park ),주권욱 ( Kwon Wook Joo ),김근호 ( Gheun Ho Kim ),이정상 ( Jung Sang Lee ),한진석 ( 대한신장학회 2003 Kidney Research and Clinical Practice Vol.22 No.2

배경 : 임상에서 흔히 사용하는 이뇨제 furosemide는 비후상행각에서 Na+-K+-2CI- cotranspoter (NKCC2)를 억제하여 NaCl 재흡수를 차단하여 이뇨작용을 나타낸다. Furosemide를 장기간 투여하면 내성과 대사성 알카리증의 부작용이 발생할 수 있는데, 이는 집합관에 도달하는 소디움 증가와 관련 있을 가능성이 있다. 방법 : 저자들은 furosemide의 내성이나 부작용이 집합관 상피 소디움 통로 (ENaC) 단백발현의 변화와 관련이 있는지를 확인하고자, Sprague-Dawley rat에서 farosemide (12 mg/day)을 7일간 지속적 피하 주입한 후 반정량적 immunoblotting과 면역조직화학법을 이용하여 NKCC2, Na +-CL- cotransporter (NCC), ENaC 단백의 발현을 관찰하였다. 실험기간 동안 수분과 전해질 용액 (0.8% NaCl & 0.1% KCl)을 자유롭게 섭취하도록 하여 체액 감소를 방지하였다. 결과 : 부형약 (vehicle)을 투여한 대조군에 비하여, furosemide를 투여한 군에서 각각 요량과 요 소디움 배설이 증가하였으나, 체중, 혈청 알도스테론치 및 크레아티닌 청소율은 차이가 없었다. Furosemid 투여 후 NKCC2 단백은 피질 (151±10 vs. 100±10%, p<0.05)과 외수질 (122±5 vs. 100±3%, p<0.01)에서 증가해 있었다. ENaC 단백은 세 가지 subunit 모두 furosemide 투여 후 대조군에 비하여 피질 (α:187±25 vs. 100±22%, p<0.05; β:155±8 vs. 100±15%, p<0.05; γ:168±16 vs. 100±9%, p<0.05)과 외수질 (α:171±27 vs. 100±17%, p<0.05; β :986±91 vs. 100±33%, p<0.01; γ :242±24 vs. 100±22%, p<0.01)에서 증 가하였다. 면역조직화학법에서도 furosemide를 투여한 군의 집합관 주세포에서 ENaC β-subunit가 더 강하게 염색되었다. 결론 : 이상에서 장기간 furosemide 투여시 집합관 ENaC 발현이 증가하며, 이러한 원위부네프론의 적응 반응이 이뇨제 내성을 유발하는데 기여할 것으로 생각한다. Background : Furosemide inhibit NaCl absorption in the thick ascending limb and produce an increase in distal delivery of Na+. We carried out semiquantitative immunoblotting and immunohistochemistry of rat kidneys to investigate whether chronic furosemide infusion is associated with compensatory increases in the abundance of Na+ transporters in distal nephron. Methods : Osmotic minipumps were implanted into Sprague-Dawley rats to deliver 12 mg/day of furosemide(n=6) with simultaneous administration of 0.8% NaCl and 0.1% KCl in drinking water for 7days. Results : Compared with vehicle infused controls, urine volume and urine sodium amount were increased. However, there were no differences in body weight, serum aldosterone, and creatinine clearance. The abundance of Na+-K+-2CI - cotransporter after furosemide infusion was increased in cortex (151±10 vs. 100±10%, p<0.05) and outer medulla (122±5 vs. 100±3%, p<0.01). In furosemide infusion group, the abundance of all three subunits of epithelial sodium channel (ENaC) was increased both in cortex (α:187±25 vs. 100±17%, p<0.05; β:155±8 vs. 100±15%, p<0.05; γ :168±16 vs. 100±9%, p<0.05) and outer medulla (α:171±27 vs. 100±17%, p<0.05; β :986±91 vs. 100±33%, p<0.01; γ :242±24 vs. 100±22%, p<0.01). Consistent with these results, ENaC β-subunit immunohistochemistry showed a remarkable increase in immunoreactivity in the principal cells of collecting ducts with furosemide treatment. Conclusion : These increases in the abundance of ENaC protein may account for the generation of diuretic tolerance.

원위부 신세뇨관성 산증에서 산-염기 운반체의 결손

김혜영,한진석,이정상,김현리,김진,이중건,이서진,김근호,진호준,전은실,주권욱,나기영,정우경,오지은,엄재호,궁성수 대한신장학회 2000 Kidney Research and Clinical Practice Vol.19 No.5

The purpose of this study was to elucidate whether the molecular defect of acid-base transporters in renal tubules is related to the functional defect of urinary acidification in distal renal tubular acidosis(RTA). We performed NH₄Cl, furosemide, or bicarbonate loading test to evaluate renal acidification function, and immunohistochemistry using antibodies to H^+ -ATPase, Cl^-/HCO₃^- exchanger(band-3 protein), and Na^+/K^+ -ATPase in kidney tissue in 6 patients with RTA and renal cell carcinoma patients as normal controls. Kidney tissue was obtained either by percutaneous needle biopsy(RTA) or nephrectomy(NC). The results were as follows; 1) In all six RTA patients, proton secretory defect of distal acidification was shown by a failure to lower the urine pH after NHC1 loading or furosemide test or abnormally low urine-blood pCO₂ difference during bicarbonate loading. In two patients with RTA, proximal acidification defect was combined, which was demonstrated by increased fractional excretion of bicarbonate. 2) In mal control, intense H^+ -ATPase and band-3 protein staining was observed in collecting ducts. 3) In distal RTA patients, H6+ -ATPase and band-3 protein staining was not demonstrable or markedly decreased in the intercalated cells of distal nephron. 4) In two patients who had both proximal and distal RTA, H^+ -ATPase staining was markedly decreased in the brush border of proximal tubules as well as the distal nephron. In conclusion, the defect of acid-base transporters in renal tubule was related with the functional defect of urinary acidification in distal RTA.

고속 주행 모드에서 자동차 디퓨저의 스트레이크 개수와 배치에 따른 공기저항 유동해석

이진호,박성하,최동석,한영진,곽나영,이상욱 순천향대학교 부설 산업기술연구소 2021 순천향 산업기술연구소논문집 Vol.27 No.2

This study proposes an optimized diffuser strake design that can improve driving performance for cars in high-speed driving mode. The speed of the vehicle is set to 160km/h, and the number of strake is set to 4, 6 and 8, and the angle of the diffuser is set to 4, 5 and 6 degrees. The arrangement of the strake is centered, edged and equally arranged. The optimized diffuser design induced with the Ansys Fluent analysis shows a drag coefficient of 16% less than the basic diffuser-free model at a diffuser angle of 6 degree, 8 strakes, and equal arrangement.

중수도 운전현황분석에 의한 건축 용도별 중수도 특성 분석

나욱호,최미영,홍원화 대한건축학회 2003 대한건축학회 학술발표대회 논문집 - 계획계/구조계 Vol.23 No.1

The water is the key resource of human's life in this planet. All of creatures to live their life being makes necessity of water in other words water is originating the entire resources. Even though highly valuable ones, the actual water operation system in developing country, especially Korea, appears to ignore the importance of this water efficiency. Thus, this research have focused here to make the water operation efficient by classifying as the objectivity and the scale. To assess the hygiene water (graywater) operation sate in developing country, in particular korea is very crucial step to make a master plan for national water resource. According to this purpose, this research starts here to analysis the graywater statue in terms of treatment process, systemic operations and the using logistics etc.; in large sized building such like manufacturing plants, shopping malls and hotels. That data which have obtain through this case studies will provide the optimal size facilities of graywater for the sake of operating of new or old buildings.

장기간 이뇨제 투여에 따른 요 산성화 능력과 집합관 H^(+)-ATPase 발현의 변화

김근호,나기영,한진석,오윤규,이정상,주권욱,엄재호 대한신장학회 2002 Kidney Research and Clinical Practice Vol.21 No.2

목 적 : 저자들은 임상에서 흔히 사용하면서 대사성 알칼리증을 유발할 수 있는 furosemide와 hydrochlorothiazide를 장기간 투여할 때 발생하는 요 산성화능의 변화를 관찰하고, 이에 동반하여 근위세관 및 헨리고리관의 NHE3와 집합관의 H^(+)-ATPase 단백 발현에 변화가 있는지 조사하고자 하였다. 방 법 : Sprague-Dawley rat에서 수분과 전해질 용액을 자유롭게 섭취시키면서 furosemide12 mg/day/rat 혹은 hydrochlorothiazide 7.5 mg/day/rat을 각각 7일간 지속적 피하 주입시킨 후 신장에서 반정량적 immunoblot 분석을 시행하여 대조군과 비교하였다. 결 과 : Furosemide 투여 후 대조군과 실험군 사이에 체중, 혈청 알도스테론 및 크레아티닌청소율은 차이가 없었다. 요량 및 요 소디움 배설은 furosemide 투여 후 현저하게 증가하였다. 요 pH가 furosemide 투여 후 감소하였고, 요 암모늄 배설은 furosemide 투여 후 증가하였다. 반정량적 immunoblot 분석 결과 furosemide 투여 후 신 피질의 NHE3 발현에 유의한 변화는없었으나, 신 외수질의 NHE3 발현은 실험군(182±25%)에서 대조군(100±25%)에 비해 증가하였다(p<0.05). 또한, H^(+)-ATPase B1 subunit 발현은 furosemide 투여 후 신 피질(대조군100±13%, 실험군 178±11%, p<0.01)과 신 외수질(대조군 100±29%, 실험군 239±24%, p<0.05)에서 모두 증가하였다. Hydrochlorothiazide 투여 실험에서도 요량 및 요 소디움 배설의 증가와 요 pH의 감소를 확인하였다. 신 피질과 외수질의 NHE3 발현은 hydrochlorothiazide투여 후 변화 없었으나, H^(+)-ATPase B1 subunit 발현은 신 피질(대조군 100±24%, 실험군212±27%, p<0.05)과 신 외수질(대조군 100±13%, 실험군 194±13%, p<0.01)에서 모두 증가하였다. 결 론 : 장기간 furosemide 혹은 hydrochlorothiazide 투여에 의해 원위 요 산성화 능력의 항진을 확인하였고, 이는 집합관 H^(+)-ATPase 단백 발현이 증가하여 발생한 결과로 설명할 수 있을 것으로 생각한다. Purpose : Commonly used diuretics such as furosemide and hydrochlorothiazide may cause metabolic alkalosis by increasing proton secretion from distal nephron. We evaluated changes in urinary acidification and abundance of proton-secreting transporters in response to chronic subcutaneous infusion of diuretics. Methods : Osmotic minipumps were implanted into Sprague-Dawley rats to deliver 12 mg/day furoemide or hydrochlorothiazide 7.5 mg/day for 7 days. All animals were offered tap water and a solution containing 0.8% NaCl and 0.1% KCl as drinking fluid. Results : Compared with vehicle-infused controls, diuretic and natriuretic responses were evident from furosemide or hydrochlorothiazide infusion. However, there were no changes in body weight, serum aldosterone and creatinine clearance between diureticinfused( n=6) and control(n=6) rats. In both furosemide- infused and hydrochlorothiazide-infused rats, urine pH was significantly lowered compared with controls. Furosemide-infused rats showed significantly larger excretion of urinary ammonium. Semiquantitative immunoblotting was carried out from rat kidneys to investigate abundance of proximal tubule or medullary thick ascending limb Na^(+)/H^(+) exchanger type 3(NHE3) and collecting duct H^(+)- ATPase using specific polyclonal antibodies to NHE3 and H^(+)-ATPase B1 subunit, respectively. The abundance of NHE3 from cortical homogenates was not changed by either furosemide or hydrochlorothiazide infusion. However, the abundance of NHE3 from outer medullary homogenates was increased by furosemide infusion. The H^(+)-ATPase B1 subunit abundance was increased by furosemide or hydrochlorothiazide infusion in both cortical and outer medullary homogenates. Conculsion : These increases in the abundance of proton-secreting transporters may account for the enhanced distal urinary acidification in response to chronic diuretic administration. (Korean J Nephrol 2002;21(2):222-231)

연속파형 Nd:YAG 레이저에 의한 인코넬 600의 용접 공정변수의 연구

배신철,유영태,송성욱,신호준,나기대 朝鮮大學校 機械技術硏究所 2004 機械技術硏究 Vol.7 No.1

The laser welding process is one of the most advanced manufacturing technologies owing to its high speed and deep penetration. Welding characteristics of Inconel 600 Alloy using a continuous wave Nd:YAG laser are experimentally investigated. The major process parameters studied in the present laser welding experiment were position of focus, laser power, travel speed. The gap and offset maintained as small as possible. Optical microscope were used to investigate the microstructures of the welded zone. The follow conclusions can be drawn the laser power and travel speed have a pronounced effect the fusion zone size and shape.

<i>Sargassum hemiphyllum</i> Inhibits Atopic Allergic Reaction via the Regulation of Inflammatory Mediators

Na, Ho-Jeong,Moon, Phil-Dong,Ko, Seong-Gum,Lee, Hee-Jung,Jung, Hyun-Ah,Hong, Seung-Heon,Seo, Youngwan,Oh, Jay-Min,Lee, Bong-Ho,Choi, Byoung-Wook,Kim, Hyung-Min The Japanese Pharmacological Society 2005 Journal of pharmacological sciences Vol.97 No.2

<P><I>Sargassum hemiphyllum</I> (SH) has long been used in Korean folk medicine for the therapeutic treatment of various allergic diseases. The effects of SH in previous experimental models, however, have been inconclusive. We studied the effects of methanol extract of SH on mast cells. Our experiments showed that SH significantly inhibited compound 48/80-induced histamine and β-hexosaminidase release from rat peritoneal mast cells. SH inhibited interleukin (IL)-8 and tumor necrosis factor (TNF)-α release induced by phorbol 12-myristate 13-acetate and A23187 from HMC-1, and it also showed an inhibitory effect on the anti-dinitrophenyl IgE antibody-induced passive cutaneous anaphylaxis reaction. In addition, SH inhibited the increase of TNF-α-induced NF-κB protein levels, transcription factor of TNF-α from 293T cells. A period of 48 h exposure to SH had little effect on HMC-1 cell viability. Our results suggest that SH has an inhibitory effect on the atopic allergic reaction and thus this may be useful in the treatment of allergic inflammatory diseases, such as atopic dermatitis.</P>

온실의 구조설계용 작물하중 산정

나욱호(Wook-Ho Na),이종원(Jong-Won Lee),라쉬드아드난(Adnan Rasheed),곽철순(Cheul-Soon Kwak),이시영(Si-Young Lee),윤용철(Yong-Cheol Yoon),이현우(Hyun-Woo Lee) (사)한국생물환경조절학회 2017 시설원예‧식물공장 Vol.26 No.4

본 연구에서는 온실의 구조설계용 작물하중을 산정하는데 필요한 기초자료를 제공하기 위하여 각국의 온실구조설계용 작물하중 기준들을 비교분석하고 여러 가지 온실작물들에 대하여 작물하중을 직접 측정하고 분석하였다. 설계 작물하중에 대한 각국의 기준들을 비교분석한 결과 나라들 마다 서로 많은 차이를 보여주고 있으며, 우리나라 기준들은 외국의 기준들을 그대로 인용하고 있는 것으로 나타나 우리나라 실정에 맞는 작물하중 기준이 제시될 필요가 있다고 판단된다. 최대 주당 작물하중이 토마토는 두 가지 온실에서 각각 3.3kgf·plant<SUP>-1</SUP>와 3.9kgf·plant<SUP>-1</SUP>로 나타났고, 오이는 0.75kgf·plant<SUP>-1</SUP>, 가지는 1.9kgf·plant<SUP>-1</SUP>, 딸기는 재배베드를 포함하여 2.1kgf·plant<SUP>-1</SUP> 으로 나타났다. 단위면적당 작물하중은 토마토가 평균 8.5kgf·m<SUP>-2</SUP>으로 나타났고, 오이와 가지는 각각 2.1kgf·m<SUP>-2</SUP>과 2.4kgf·m<SUP>-2</SUP>으로 토마토의 하중보다 훨씬 낮게 나타났다. 우리나라 온실설계기준에 제시된 작물하중은 토마토와 오이의 경우 15kgf·m-2으로 본 연구에서 측정된 값보다 훨씬 높았다. 우리나라의 설계기준이 네덜란드의 기준을 그대로 인용한 것으로 판단되기 때문에 이러한 차이를 고려하여 우리나라의 작물하중 설계기준에 대한 재검토가 이루어져야 할 것으로 판단된다. 딸기의 작물하중은 행잉베드를 포함한 중량이 21.0kgf·m<SUP>-2</SUP>로 네덜란드의 설계기준인 30kgf·m<SUP>-2</SUP>보다 훨씬 작았다. This study was conducted to provide basic data needed to calculate the crop loads for the greenhouse design. Four countries’ crop loads for greenhouse structures were compared and the crop loads were measured directly and analyzed for various greenhouse crops, including tomato, strawberry, cucumber, and eggplant. According to the analysis results of four country’s standards for the design crop loads, it was judged that the new design crop loads suit for greenhouse crops in our country should be suggested because our standards just used the design crop loads of other countries. The maximum crop loads per plant of tomato, cucumber, eggplant, and strawberry were 3.9, 0.75, 1.9 and 2.1 kgf·plant<SUP>-1</SUP>, respectively. The crop load per unit area of tomato was 8.5 kgf·m<SUP>-2</SUP>, which was much greater than the cucumber and eggplant’s crop load of 2.1 and 2.4 kgf·m<SUP>-2</SUP> respectively. The crop loads of tomato and cucumber, suggested by the greenhouse structure design standard of Korea, is 15 kgf·m<SUP>-2</SUP>, which is far greater than the values suggested by this research. It was judged that this was because our standard just used the Dutch standard, our crop load standard should be reviewed considering this difference. The crop load of strawberry, including the growing bed, was 21.0 kgf·m<SUP>-2</SUP>, which was much greater than the crop load in the Dutch standard.

대구시 하수종류에 따른 하수처리장 운전실태 및 중수도 시설 도입 방안에 관한 연구

나욱호(Na Wook-Ho),최미영(Choi Mi-Young),도형윤(Do Hyung-Ryun),홍원화(Hong Won-Hwa) 대한건축학회 2003 대한건축학회 학술발표대회 논문집 - 계획계/구조계 Vol.23 No.2

It apparently appear water resources necessity rate rapidly, developing system and densified city, increasing population. Further water resource is expected to needed more than current requiring rate. On this matter, there are considered the hygiene water(graywater) operation by classifying as the objectivity and the scale due to the fact sewage is supplied as closed distance in city and settled quantity. This way which sewage is used as quantitative resource and increased operation efficiency that some screening systems have not been properly installed and that virtually raw sewage is being discharged in right place. This method leads secured water resource and easily developed the water type as a secondly treatment as well as reducing treatment expense by defining water type, decreasing a environmental demage risk. The research has focused on this point to analysis the graywater statue in terms of treatment process, systemic operation and the using logistics on based on figure supplied by Daegu City sewage Agency. That data which have obtain through this case study will provide the optimal size facilities of graywater in developing country, especially Korea is crucial step to make a master plan for national water resource.