Numerical Analysis of Radio‑Frequency Inductively Coupled Plasma Spheroidization of Titanium Metal Powder Under Single Particle and Dense Loading Conditions

Jun‑Seok Nam,Eonbyeong Park,Jun‑Ho Seo 대한금속·재료학회 2020 METALS AND MATERIALS International Vol.26 No.4

In order to allow more practical prediction of RF (radio-frequency)–ICP (inductively coupled plasma) spheroidizationresults of titanium metal powder, numerical analyses under single particle and dense loading conditions were carried outand the results were compared. First, both of the numerical results for Ar inductively coupled plasma with the power levelof 30 kW revealed that the injected particles can experience not only spheroidization by melting, but also size reduction byevaporation. In addition, this size reduction was found to strongly depend on the initial sizes of the injected particles, due tothe relatively short heating time. For example, the 100 μm Ti particles were computed to hardly experience size reduction byevaporation regardless of feeding rates. However, relatively small Ti particles < 100 μm can be rapidly heated up to boilingpoints during the short flight of plasma, resulting in the size reduction by the surface evaporation. In particular, numericalresults under dense loading condition showed that the final sizes of these small Ti particles can be changed depending onthe feeding rate. For example, a single 60 μm Ti particle was calculated to be a 51 μm spherical Ti particle due to the excessiveheating. However, with the increase of feeding rate up to 1.0 kg/h, the final sizes of the as-treated Ti powder couldbe improved to 55 μm due to the plasma temperatures decreasing through complicated plasma–particle interactions. Bypredicting the relationships between the feeding rates and the initial diameters of Ti powders at a given plasma power level,numerical modellings under single particle and dense loading conditions can help in optimizing the RF–ICP spheroidizationprocess of titanium metal powder.

당(唐) 태종대(太宗代) 반위(反胃) 치료법의 개발과 백제(百濟) 의자왕(義慈王)의 질병

박준형 ( Park Jun-hyoung ),서영교 ( Seo Young-kyo ) 대구사학회 2021 대구사학 Vol.142 No.-

唐은 기본적으로 隋의 의료체계를 수용하면서도 醫術世家의 秘傳에 의해 분산ㆍ난립된 醫術의 독점을 국가의 의료체계라는 公的 영역으로 흡수하고자 하였다. 나아가 당은 그 의술을 민간에 유포함으로써 점차 의술세가의 독점적 입지를 좁혀 나갔다. 공익을 위한 의술 공개는 당 왕조의 존재 이유를 백성들에게 가장 효율적으로 각인시키는 방법의 하나였고, 이는 초기 왕조의 안정화에 기여하였다. 당 태종대 당나귀오줌을 이용한 반위 치료법 개발은 이러한 의료정책의 결실이었다. 蔣ㆍ許ㆍ巢氏 醫官들의 연구를 통해 이루어낸 새로운 치료 법은 즉위 초반부터 숙환이 있던 의자왕에게도 주목받았다. 644년 초 의자왕은 당에 파견된 사신을 통해 의사를 알아보았고, 그해 말 입당한 태자 夫餘康信이 당 태종에게 蔣元昌의 왕진을 요청했다. 당시 장원창은 益州道로 파견나가 있었기 때문에 당 태종은 그를 백제에 보낼 수 없었다. 결과적으로 태자를 보내 백제의 신라공격에 대한 입장을 해명하고 신라를 침공하지 않겠다고 약속했던 의자왕이 645년에 신라를 공격했다. 그해 고구려와 전쟁을 시작한 당 태종은 신라를 이용하여 고구려의 병력을 남쪽으로 분산시키고자 했던 의도가 무산되었다. 현재 학계에서는 백제의 신라 공격 이유를 명확하게 설명하지 못하고 있다. 645년 백제의 신라 공격으로 백제와 당의 관계가 악화되었다. 이는 신라가 대당외교에서 성공할 수 있는 여건을 만들어 주었다. 이런 점에서 645년 백제의 신라 공격은 의자왕의 질병과 의사 장원창의 왕진 요청 거부가 중요하게 작용했던 결과라고 할 수 있다. Tang China(618-907), which inherited the medical system of the preceding Sui China(589-618), attempted to reorganize it by absorbing various medical traditions which were then monopolized by hereditary medical families. The hereditary remedies and knowledge of medical specialists who were employed as government physicians were integrated into the state medical system, and the newly developed remedies were open to public. The development of Banwi (反胃, gastric disorder) remedy using donkey urine was one of the cases demonstrating the success of the early Tang medical system. The remedy, developed through a joint research by the physicians from three prestigious medical families in early Tang, was soon to be known to Baekje. King Uija (r. 641-660) of Bakje, who had been suffered from Banwi, dispatched envoys to Tang to ask to send Jiang Yuan-chang to Baekje in 644. The Baekje court seems to have regarded Jiang, a physician who participated in the development of new Banwi remedy, as the most qualified person to cure King Uija. Tang government, however, could not dispatch Jiang to Baekje as he was then working near Sichuan province, hundreds miles from Chang'an, the capital of Tang. As a result, King Uija missed a chance of being treated with the new remedy. Then Baekje, which had once promised not to attack Shilla by sending a prince to Tang, resumed invasion of Shilla in 645, spoiling Emperor Taizong's (r. 626-649) plan to mobilize Baekje's army in his campaign against Goguryeo. As the aftermath of this incident, the relation between Baekje and Tang was irreversibly deteriorated, while Shilla succeeded to consolidate the Shilla-Tang alliance which led to the fall of Baekje in 660. From the perspective of medical diplomacy between Baekje and Tang during the mid 7th centuries, Tang’s failure to meet Baekje’s request for the medical support might have had a grave effect on the Baekje’s decision to move against the Tang’s interests. Park, Jun-hyoung (Naval Academy / shimani5075@hanmail.net) Seo, Young-kyo (Jungwon University / syk367@naver.com)

자동차차체 및 부품제조업 산업장의 작업환경실태에 관한 조사 연구

서준호,문덕환,김정호,이채관,황용식,손병철,김대환,이창희,김휘동,이채언 인제대학교 백병원 2002 仁濟醫學 Vol.23 No.5

Objectives: For the purpose of preparing the fundamental data and control the working environment and assessing the status of working environmental in manufacturing industry of bodies for motor car and of parts. Methods and Materials: Accessories for motor car and its engines the auther measured the noise level, concentration of dust, heavymetals, organic solvents, chemicals to 99 industries(24 working processes) form Feb. 2000 to Oec. 2000. Results: The results were as follows : 1. Mean noise level cutting, grinding, pressing, foundries and shot-blast was exceeded to threshold limit value(TLV) of noise. 2. Mean concentration of total dust was not exceeded to TLV. 3. Mean concentration of Mn in welding process and Pb in drying, welding, fabricating, rolling was exceeded to TLV. 4. Mean concentration for chemicals and organic solvents were not exceeded to TLV. 5. Mean concentration of dust and heavymetals were statistical significant difference between with local ventilation system and without local ventilation system. Conclusion: Above results, author suggest to prepare more passively control to working environment where exceeded the TLV.

한국만화산업의 수출경쟁력 강화방안에 관한 연구

徐俊奭,徐敏敎 慶一大學校 1999 論文集 Vol.16 No.4

Recently, there has been rapid increase in Korean firms' export of cartoon products, reflecting the change of world and domestic economic environment. The purpose of this study are 1) to find out results of comparative study on cartoon industry between Korea and Japan 2) to evaluate possible implications for Korean firms' export of cartoon products and consider the effcient countermeasures of Korean firms.

국내은행 데이터베이스마케팅전략에 관한 연구

徐俊奭 慶一大學校 1999 論文集 Vol.16 No.4

Recently, there has been rapid increase in database marketing between domestic banks and foreign banks, reflecting the change of world and domestic economic enviroment. The purpose of this study are 1) to find out comparative study on database marketing among Korean, Japanese and American banks 2) to evaluate possible implications for Korean banks's database marketing strategy and consider the effcient countermeasures of Korean banks.

생체신호 처리용 ASIC 칩 개발

서희돈,이준하 경북대학교 센서기술연구소 1997 연차보고서 Vol.1997 No.-

폐하수처리제를 이용한 제지폐수의 처리

서정범,배준현 안양대학교 자연과학연구소 1996 自然科學硏究 Vol.3 No.-

셀루로스 분해 균주인 cytophaga sp.를 이용하여 실제 폐수처리시설에서의 적용 가능성과 폐수처리효율에 미치는 영향을 검토하였다. 합성 제지폐수에 cytophaga sp.를 투여하고 행한 회분식 실험에서 4시간 후 COD_Cr 처리효율이 약 20% 증가되었다. 그러나 24시간 경과 후에는 차이가 없었다. 실제 제지폐수에 cytophaga sp.를 투여하고 행한 회분식 실험에서는 4시간 후의 COD_Cr 처리효율은 차이가 없었으나 6시간 후에는 10% 증가되었다. 생물처리제의 투여량을 증가시킴에 따라 처리효율도 증가되었다. 실제 제지폐수에 cytophaga sp. 20mL/day를 투여하고 행한 연속식 처리실험에서 BOD, COD_Cr, COD_Mn 처리효율이 각가 8.6%, 20%, 13.5% 증가되었으며, 투여량 변화에 따른 처리효율의 변화는 없었다. Cytophaga sp.를 투여함에 따라 물질대사계수(K_m)가 상승되는 것으로 보아 난분해성 섬유소가 분해성으로 전환된 것으로 판단되었다. The appricabilty at the practical plant and the effect on the treatment efficiency were estimated by using cytophaga sp. as a cellulose degrading bacterium. At the batch-type treatment of synthetic paper mill wastewater with cytophaga sp., about 20% treatment efficiency on COD_Cr was increased at 4 hours, but at 24 hours there was little difference. At the batch-type treatment of wastewater from the paper mill with cytophaga sp., treatment efficiency on COD_Cr was almost equivalent at 4 hours, 10% was increased at 6 hours, but 25 hours there was little difference, the efficiency was increased in the proportion to the increment of the dosage amount of the agent. At the continuous treatment of paper mill wastewater with 20 mL/day cytophaga sp., efficiencies of BOD, COD_Cr, COD_Mn increased 8.6%, 20%, 13.5%, respectively and the difference was not much according to the dosage amount. From the increment of K_m, metabolic coefficient by the dosage of cytophaga sp., it was estimated to be converted from recalcitrant cellulose in paper mill wastewater to biodegradable organics.

관상동맥 누공에 의한 급성 심근 경색 1예

서유승,최재웅,송창섭,조용범,양진수,박준섭,정인수 대한내과학회 2003 대한내과학회지 Vol.65 No.2

관상동맥 동정맥루 기형은 매우 드문 질환으로 치료가 불필요한 경우가 대부분이나 coronary steal 현상으로 인해 증상이 발생하거나 합병증이 발생한 환자에 대해선 치료를 요한다. 최근에는 시술에 적합한 누공을 가진 선택된 환자군을 대상으로 카테터를 이용한 중재적 시술이 시행되어 수술적 치료와 유사한 결과를 얻고 있다. 저자들은 젊은 남자에서 관상동맥 동정맥루 기형과 동반된 급성 심근 경색증을 진단하여 비 수술적 방법인 카테타 코일 색전술로 성공적 치료 후 증상 및 심근 재관류에 호전을 보인 증례를 경험하였기에 문헌고찰과 함께 보고하는 바이다. We report a case of coronary fistula between the left anterior descending and main pulmonary artery complicating acute non-Q wave myocardial infarction. A 27-year-old man visited emergency department because of severe chest pain lasting two hours. The electrocardiogram showed ST segment elevation in precordial leads V3~6. Cardiac enzymes were as follows;CK-MB:36.44 IU/L T-T:0.489 ng/mL, CPK:542 IU/L, and LDH:475 IU/L. The thallium-201 dipyridamole stress perfusion scan showed perfusion defect and reversed redistribution in the anteroseptal wall. The coronary angiogram revealed coronary artery fistula between the proximal left anterior descending artery and main pulmonary artery without significant stenoses of coronary arteries. The result of ergonovine test was negative. After micro-coil embolization to the coronary fistula, symptoms were improved. Follow-up thallium-201 scan showed normalized blood flow in the left anteroseptal wall.

FDM에서 경사면의 표면과 면적오차법의 관계에 대한 연구

전재억,정진서,황영모,김수광,김준안,계중읍,하만경 한국공작기계학회 2002 한국공작기계학회 추계학술대회논문집 Vol.2002 No.-

In any rapid prototyping process, the layer by layer building process introduces an area error between the staircase and the surface line specified by the computer-aided design model. This affects the dimensional accuracy as well as the surface finish for different part build orientations. This paper describes a methodology for computing the area error for any orientation of the part built by the fused deposition modelling system. This technique can be applied to determine the best build orientation of the part, based on the minimum area error. This technique is verified by comparing the results with the experimental measurements of the area error of the parts built at different orientations.

1993년 신입생 실태조사 결과분석

전광희,편서영 충남대학교 1994 學生生活硏究 Vol.21 No.-