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.

忠南 錦山郡 西臺山 一帶의 나비目 昆蟲相

남상호,조영호,장석원,박영준,이선영,나선희 대전대학교 기초과학연구소 2002 自然科學 Vol.13 No.2

충청남도 금산군 서대산 일대의 나비목 곤충상을 조사한 결과 22과 344종 1,936개체가 조사되었다. 이중 밤나방과가 102종 589개체, 자나방과가 67종 440개체로 이 2과가 전체의 50%이상을 차지하였다. 자나방과의 두줄가지나방은 1,936 개체중 85개체가 채집되어 4.4%의 가장 높은 우점도를 나타냈다. 월별 우점종은 4월 노랑무늬물결자나방, 5월 별박이세줄나비, 6월 목도리불나방, 7월 청백무늬밤나방, 8월 두줄가지나방, 9월은 털뿔가지나방이 조사되었다. 월별 종다양도는 4월 2.95, 5월 3.37, 6월 4.63, 7월 4.62, 8월 4.23, 9월은 2.97이었으며, 평균 종다양도는 3.80으로 서대산 일대의 나비목 곤충상은 비교적 양호한 편으로 조사되었다. This study was carried out to investigate Lepidopterous insect fauna from Mt. Seodae in Geumsan-gun, Chungnam. The samples were collected from April to September in 2001. Total 1,936 individuals belonging to 344 species, 22 families of Lepidoptera were collected. The sum of individuals belonging to Noctuidae and Geometridae exceed 50% of the collected samples in that Noctuidae was consisted of 102 species 589 individuals and Geometridae was 67 species 440 individuals. The dominant species in surveyed area was Rikiosatoa grisea of Geometridae, the dominant species by month were Idiotephria amelia in April, Neptis pryeri in May, Paraona staudinger in June, Ercheia niveostrigata in July, Rikiosatoa grisea in August and Alcis angulifera in September respectively. Species diversity indices by month were 2.93 in April, 3.37 in May, 4.63 in June, 4.62 in July, 4.23 in August and 2.97 in September respectively. Mean species diversity index was 3.80.

송이의 碎石다짐말뚝에 대한 材科 適合性에 관한 硏究

남정만,김준호,김인석 제주대학교 해양과환경연구소 2005 해양과환경연구소 연구논문집 Vol.29 No.2

항균 활성을 가진 천연약재의 검색

송형석,이지연,오성준,백남인,김해영 경희대학교 생명자원과학연구원 2000 硏究論文集 Vol.21 No.-

We investigated the antimicrobial activity of the hot-water extracts and methanol extracts from medicinal plants. Sixty-two samples were tested by disk diffusion method at concentrations of 5,000ppm and 10,000ppm. Seven species of medicinal plants showed a significant antimicrobial activity against various food-borne microorganisms.

도로판형교의 Life-Cycle Cost 최적설계

조효남,민대홍,조준석 漢陽大學校 工學技術硏究所 2000 工學技術論文集 Vol.9 No.1

본 연구에서는 강판형교에 대하여 총기대비용을 최소화하는 최적설계모델을 제안하였다. 총기대비용은 전체 공용기간을 고려하여 초기비용(설계비용, 개통전 검증재하시험비용, 건설비용), 유지보수비용 및 기대파괴비용을 포함하고 있다. 설계변수들에 대해 총기대비용을 최소화하는 문제로 정식화하였고, 거동제약조건은 휨파괴와 전단파괴의 형태로 되어 있다. 이러한 총기대비용 최적설계를 수행함으로써 효율적이고 합리적인 비용산정을 통해 총기대비용 설계의 근거를 제시하고 구조물 총기대비용에 관한 민감도 분석을 하였다. 수치해석을 통해 본 연구에서 제안된 총기대비용에 근거한 강판형교의 최적설계가 기존 초기비용 설계에 비해 훨씬 합리적이고 경제적인 설계가 될 것이며 향후 구조물 설계에서 추구해 나가야 할 차세대 성능기준 설계와 매우 밀접한 설계법임을 알 수 있다. This paper presents an optimum design model for minimizing the life-cycle cost (LCC) of steel plate girder bridges. The point is that it takes into account service life process as a whole, and thus the life-cycle costs include initial (design, testing, and construction) costs, maintenance costs and expected failure costs. The problem is formulated as that of minimization of expected total life-cycle cost with respect to the design variables. The performance constraints are considered in the form of flexural failure and shear failure. By processing the optimum LCC design the effective and rational basis is proposed for calculating the total LCC and the sensitivity analysis of LCC is performed. Based on a numerical example, it may be positively stated that the optimum LCC design of steel plate girder bridges proposed in this study provides a lot more rational and economical design, and thus the proposed approach will expedite the development of new concepts and design methodologies that may have important implications in the next generation performance-based design codes and standards.

석청(Mad-honey) 복용 후 유발된 부정맥 1예

김용철,김남호,김승환,최준호,박은미,이상재,이은미,유남진,윤경호,오석규,정진원 圓光大學校 醫科學硏究所 2008 圓光醫科學 Vol.23 No.2

석청에 포함된 grayanotoxin에 의해 독성 작용이 나올 수 있으며, 이러한 독성 작용은 일반적으로 24시간 이내 저절로 회복된다. 최근에 본 저자들은 석청 복용 후 발생한 심실빈맥을 경험하였기에 보고하는 바이다. 49세 남자가 호흡곤란으로 내원하였으며, 내원당시 분당 40회 정도의 동성 서맥이 관찰되었고, 수액을 투여하던 중 심실 빈맥이 발생하였다. 항부정맥제를 투여 후 정상 동율동으로 전환되었으며, 특별한 이상 없이 4일 후 퇴원하였다. Mad-honey intoxication caused by the consumption of honey producted from the nectar of rhododendrons. The grayanotoxins cause the intoxication. The toxic effects of mad-honey poisoning are rarely fatal and generally last for no more than 24 hours. We experienced one case, a 49 years-old man who presented with dyspnea after ingestion of mad-honey. He showed marked sinus bradycardia with < 40 beats per minute on admission. The cardiac rhythm was changed to ventricular tachycardia immediately. These features resolved completely in 24 hours with continuous infusion of amiodarone(600 mg per day) and fluids. We report the case of intoxication of mad-honey as a presentation of fatal cardiac arrhythmia.

Sheehan 증후군 발생한 Torsades de Pointes

김승환,김남호,김용철,최준호,박은미,이상재,이은미,유남진,윤경호,오석규,정진원 圓光大學校 醫科學硏究所 2008 圓光醫科學 Vol.23 No.1

재발하는 심실 빈맥으로 내원한 환자에서 Sheehan 증후군을 진단하였고, 적절한 호르몬 보충 치료 후 심전도 이상이 정상으로 회복된 예를 경험하였기에 문헌고찰과 함께 보고하는 바이다. Torsades de Pointes is a form of polymorphic ventricular tachycardia that is associated with prolongation of QT intervals, characterized by QRS complexes of progressively changing ampulitude and cyclic length, giving the appearance of oscillations around the baseline. A 77 years-old woman was presented with hypotention and arrhythmia. Twenty four-hour ECG showed typical episodes of torsades de pointes with QT prolongation. This arrhythmia was controlled by isoproterenol and magnesium infusion, but it was not disappeared. She was diagnosed as Sheehan's syndrome by past history, anterior pituitary stimulation test and empty sella on CT scan. After hormone replacement treatment, Prolonged QT interval was normalized and polymorphic ventricular tachycardia has not recurred. We report a case of torsades de pointes associated with Sheehan's syndrome

회분식반응기에서 스티렌과 알킬아크릴레이트의 공중합의 속도론

설수덕,김남석,황준호,최경선,강현석 동아대학교 공과대학부설 생산기술연구소 1997 生産技術硏究所硏究論文集 Vol.2 No.1

Stylene(St) with Methyl Acrylate(MA), Ethyl Acrylate(EA), and n-Butyl Acrylate(BA) were carried out with benzoylperoxide(BPO) in touene. The copolymer compositions were determined by Elemental Analyzer(EA). The monomer reactivity ratio, r1 and r2 were determined by both the Kelen-Tu¨do¨s method and Fineman-Ross method. The values of r1 and r2 for each monomer pair were as follows : r1(st)=0.57(0.68), r2(MA)=0.09(0.22). The φ factor of the copolymer over all St compositions ranged from 0.64 to 2.33 and increased with increasing St compositions. The copolymerization rates of each monomer pair were determined.

好氣性 固定床 生物膜 反應槽의 메디아로 폐칫솔의 利用可能性 檢討에 관한 基礎硏究 : 처리효율을 중심으로

임채영,김정권,성낙창,신남철,김형석,전기일 동아대학교 환경문제연구소 1997 硏究報告 Vol.20 No.1

This study was conducted to evaluate the possibility to apply the waste toothbrush to aerobic fixed biofilm reactor for media. The media used for this research was waste toothbrush (WTB) and Pall-Ring. The feed used for this research was synthetic wastewater which was made at the laboratory. The COD, NH₄^(+)- N and PO₄^(-3)-P removal efficiency variations with the organic loading rate was examined at this research. The conclusions drawn from these experiments are listed below : 1. When the influent COD concentration was respectively 300mg/ℓ, 600mg/ℓ, the COD removal efficiency was decreased with the increase of the organic loading rate and the COD removal efficiency for Pall-Ring was higher than the COD removal efficiency was 0.4~1.9%. 2. When the influent NH₄^(+)-N concentration was respectively 13mg/ℓ (COD 300mg/ℓ), 25mg/ℓ (COD 600mg/ℓ ), the NH₄^(+)-N removal efficiency for Pall-Ring was slightly higher than the NH₄^(+)-N removal efficiency for Wastetooth brush. The difference of NH₄^(+)-N removal efficiency was about 0.5~1.5%. 3. When the influent PO₄^(-3)-P concentration was respectively 7mg/ℓ (COD 300mg/ℓ), 14mg/ℓ (COD 600mg/ℓ ), the PO₄^(-3)-P removal efficiency for Pall-Ring was higher than the PO₄^(-3)-P removal efficiency for Wastetooth brush. The difference of PO₄^(-3)-P removal efficiency was about 1.1~2%. 4. COD, NH₄^(+)-N and PO₄^(-3)-P removal efficiencies show very small difference between Pall-Ring and Wastetooth brush as media. So it was showed that wastetooth brush can be used as media very successfully.

하악골 골절 환자에 있어 수술후 합병증으로 발생한 골수염의 치험례

윤규호,전인성,신용길,박준호,허남오,방석준 大韓顎顔面成形再建外科學會 1996 Maxillofacial Plastic Reconstructive Surgery Vol.18 No.4

The term osteomyelitis literally means inflammation of bone marrow. It is described as an inflammatory condition of bone primarily engaging the medullary Following circulatory collapse and ischemia, the involved portions of the bone become necrotic. Cellulitis and osteomyelitis are the most frequent complications of fractures of the mandible and maxilla, because there is an abscessed tooth in the line of fracture. Since most fractures are compound fractures, infection may develop because of contact with oral secretions or outside air. The treatment of chronic osteomyelitis is still under debate. Some authors rely on antibiotics alone, while others advocate combination with surgery. But when infection occurs, establish proper drainage and administer antibiotics. Author treated a case of infected mandibular fracture with mandibular osteotomy, sequestrectomy, iliac bone graft and hyperbaric oxygen therapy, who had suffered suppurative osteomyelitis and mandibular nonunion following the open reduction of the mandibular fracture.