Effect of post annealing on the microstructure, mechanical properties, and failure of Mo_xW_1-xSi₂ heaters produced by self-propagating high-temperature synthesis

Cho, Myung-Yeon,Lee, Sung-Chul,Park, Chulhwan,Lee, Daeseok,Koo, Sang-Mo,Moon, Kyoung-Sook,Lee, Dong-Won,Oh, Jong-Min Elsevier 2019 INTERMETALLICS Vol.110 No.-

<P><B>Abstract</B></P> <P>High-performance tungsten molybdenum disilicide (Mo<SUB>x</SUB>W<SUB>1-x</SUB>Si<SUB>2</SUB>) heating elements were prepared using a self-propagating high temperature synthesis process. The effect of post annealing on the degradation behavior of the alloy was experimentally investigated. Increasing the attrition milling time up to 20 min during powder preparation resulted in Mo<SUB>x</SUB>W<SUB>1-x</SUB>Si<SUB>2</SUB> heaters with the highest density, which increased the fracture strength compared to samples with shorter attrition times. Such samples were annealed and evaluated as heating elements using accelerated degradation tests and failure analysis in order to compare their structural characteristics and flexural strength with as-fabricated samples. The annealed Mo<SUB>x</SUB>W<SUB>1-x</SUB>Si<SUB>2</SUB> heater showed a relatively dense structure with few pores and no secondary phases, apart from a SiO<SUB>2</SUB> layer. This favorable structure prevented bubble formation, which can result in fracturing of the heater, as revealed by evaluation at high temperatures with various heating rates. The flexural strength of the annealed specimen was 2.5-times higher than that of the as-fabricated specimen, which was attributed to removal of secondary phases during annealing. Failure time and surface load analyses were used to investigate the fracture mechanism of the Mo<SUB>x</SUB>W<SUB>1-x</SUB>Si<SUB>2</SUB> heaters in detail at 1790 °C by quantifying bubble formation and the presence of secondary phases.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Self-propagating high temperature synthesis of Mo<SUB>x</SUB>W<SUB>1-x</SUB>Si<SUB>2</SUB> heaters demonstrated. </LI> <LI> Post-annealed Mo<SUB>x</SUB>W<SUB>1-x</SUB>Si<SUB>2</SUB> heaters were highly dense, with good flexural strength. </LI> <LI> Bubble formation (the main cause of fracture) suppressed at ultra-high temperature (above 1700 °C). </LI> <LI> Surface load, failure time, and bubble formation used to study fracture mechanisms. </LI> </UL> </P>

한의진단명과 진단요건의 표준화 연구 III : 3차년도 연구결과 보고

최선미,양기상,최승훈,박경모,박종현,심범상,김성우,노석선,이인선,정진홍,이진용,김달래,임형호,김윤범,박성식,송태원,김종우,이승기,최윤정,신순식 한국한의학연구원 1997 한국한의학연구원논문집 Vol.3 No.1

The diagnostic requirements were suggested and explained regarding the systems of differentiation of symptoms and signs in the third year study of standardization and unification of the terms and conditions used for diagnosis in oriental medicine. The systems were as follows : - analyzing and differentiating of epidemic febrile disease - analyzing and differentiating in accordance with the Sasang constitution medicine based on four-type recognition - differentiation of disease according to pathological changes of Chong and Ren channels - standards for diagnosis of women's disease - standards for diagnosis of children's disease - standards for diagnosis of motor and sensor disturbance (-muscle. born, joint, etc.) - standards for diagnosis of neuropsychiatric disease - standards for diagnosis of five sense organ disease - standards for diagnosis of external disease The indivisual diagnosis pattern was arranged by the diagnostic requirements in the following order : another name, notion of diagnosis pattern, index of differentiation of symptoms and signs, the main point of diagnosis, analysis of diagnosis pattern, discrimination of diagnosis pattern, prognosis, a way of curing a disease, prescription, herbs in common use, disease appearing the diagnosis pattern, documents. The standards for diagnosis of each disease was arranged by the diagnostic requirements in the following order : another name, notion of disease, the main point of diagnosis, analyzing and differentiating of disease, analysis of disease, discrimination of disease, prognosis, a way of curing and prescription of disease, disease in western medicine appearing the disease in oriental medicine, documents.

한국민속에 나타난 죽음 : 이몽학과 김덕령 전승을 중심으로

朴鍾洙,姜賢模 龍仁大學校 1994 용인대학교 논문집 Vol.10 No.-

The deaths found in the Korean folklore are mutually different in form but to Koreans the death seems to represent a change of the earthly life into a new place of life, reather than an end of the worldly life. That is to say, if a man dies, flesh will disappear into dust but the soul will not die away and be born into a new life. About the forms of death in Korea folklore, this paper tries to closely examine deaths focusing on the tragic death of Lee Mong-hak and Kim Dok-ryong who were loyal soldiers. Lee Mong-hak who rose in revolt in puyo and its vicinity Hongsan against his enemy worked out a plan to ccupy areas of Hongsong but it turned out to be a failure. In his defeated war, Lee Mong-hak was killed by his subordinates, however. As for Kim Dok-ryong, he who went to war while in mourning initially advanced into as far as Chinju area but last failed to win the war. The defeat stirred up an intriguing against him from his opposing party and then this caused him to involve himself in the Lee Mong-hak Revolt, where he was killed. Noticeably the oral literature brings to light whatever conscience the men of legend-transmission(or country scholars in olden days)had about the tragic death of such loyal soldiers. Further accounts of it may be given as follows : First, men of legend-transmission most probably didn't want to see deaths like that, because they thought that such patriotic soldiers were the men to be able to deliver them from the actual trials. Second, those folk experts present a new sense of their deaths by making the narrative story of death more like a tragic one. In other words, their death, caused by sujects much weaker than they, exposes the absurdity and hypocracy of the then society. Third, the folk transmitters would not accept their tragic deaths. Instead, they turned down the tragic deaths of the two soldiers, based on the Paguteolegend of Lee Mong-hak and a thorough loyalist Kim Dok-ryong : they only displayed here the probability of their resurrection, through which the loyal soldiers might secure a solution to such actual trials as mentioned above. The deaths of Lee Mong-hak and Kim Dok-ryoung found in the legends is not the end of human life but a new birth toward another self-realization In conclusion, the legend -transmitters sought to find a new effective way in the legend to adjust themselves well to actual trials of life in an absurd and unequal society.

제트베인형 추력편향장치의 공기역학적 특성

박종호,이성노,이은모,신완순,이택상,길경섭 충남대학교 공업교육연구소 2000 論文集 Vol.23 No.1

The aerodynamic study of jetvane type TVC(Thrust Vector Control) were conducted using supersonic cold-flow system. The use of TVC Systems in particular jet vanes, are currently being researched for use in air launch, ship launch, underwater launch and high altitude maneuvering of tactical missiles and rockets. The necessity to generate control forces to rapidly change the course of the missile is frequently required when traditional, exterior aerodynamic surfaces are unable to produce these forces, when the flow over the control surface is insufficient. This situation can occur at launch, or high angles of attack of the control surfaces. Jetvanes performed well at all altitudes and environmental conditions, and jet vanes are extremely effective at deflection angles up to as high as 30 degrees, make them ideal for the launch and maneuver applications. In this study, aerodynamic performance test of jetvane type TVC was conducted, and The effect of shape and deflection angle of various types of jetvanes are investigated

瘀血病態模型 개발에 관한 硏究

朴耕模,朴種鉉,安圭錫 대한동의병리학회 1999 동의생리병리학회지 Vol.13 No.1

현재까지 개발된 어혈 동물모형들은 각각 그 특성이 달라 약물의 활혈화어 효과를 검증하는데 일괄적으로 적용시킬 수 없는 난점이 있었고, 실험상 변수의 통제가 어렵고 정확한 기전을 밝히기도 어려울 뿐 아니라 비용이 많이 들어 대규모적인 스크리닝을 하기가 힘들었다. 따라서 이들 모형의 차이점을 비교검토할 필요가 있고 이 문제점들을 보완해줄 in vitro에서의 새로운 병태모형이 필요하여 본 연구를 실행하였다. 동물을 이용한 어혈 모형의 경우, 혈전증모형은 출혈기전과 응고기전과 관련있는 어혈모형으로 생각되며, HA와 dextran으로 유발한 고점도혈증은 응고기전과 직접 관련되는 모형이라기 보다는 혈액의 점성이 증가되어 혈의 흐름이 정체되어 나타나는 혈어모형에 가깝다고 볼 수 있다. 압상어혈모형은 대퇴부의 압박으로 인한 국소 어혈모형이며, 전신의 혈류상태에는 큰 영향을 미치지 않았다. 또한, in vitro에서는 ECV304 cell line과 ECVPAR cell line에서의 세포부착효과, Angiogenic lumen formation, MMP-9, uPA의 발현양상, Integrin αvβ3, LFA-1, ELAM-1의 발현 등을 지표로 삼아 혈관신생을 통한 어혈병태모형을 구축하였으며, 이 모형은 기존 동물에서의 어혈모형의 문제점들을 보완할 수 있을 것으로 생각된다. This experimental study was carried out to characterize in modern medical understanding the concept of Blood Stasis as proposed in the traditional medical system of Korea, Japan, and China. Another objective was to construct a new model of blood stasis via in vitro. We divided the original model of blood stasis into three catergories: thrombosis, high blood viscorsity and trauma. The thrombosis model was induced by endotoxin and is related to the mechanisms of bleeding and coagulation. the high blood viscosity model was induced by hydrocortisone acetate and dextran and is related to the hemodynamic derangement rather than the bleeding and coagulation. the trauma model was induced by compression and is related to the local and hematological change by the compression of the thigh of rats. Finally, we induced an in vitro blood stasis model using ECV304 and ECVPAR cell lines. The focus being inducing angiogenesis and correlating the mitigating factors of cell adhesion, angiogenic lumen formation, mRNA expression of MMP-9 and uPA, and expressions of integrin αvβ3, LFA-1 and ELAM-1. We expect that this model may complement the problems associated with the original models.

차세대 고속철도 특수교량의 설계 및 기술사양 조사

박만호(Park Man-Ho),문제우(Mun Je-U),김성일(Kim Sung-Il),홍성모(Hong Seong-Mo),김종태(Kim Jong-Tae) 한국철도학회 2008 한국철도학회 학술발표대회논문집 Vol.- No.-

Mo-Am arch bridge is only the long-span bridge (with 125m span) in the Kyong-Bu high-speed line in service, while other bridges are PSC box girder bridges and steel composite bridges with span lengths of 25~50m. However, in foreign high-speed lines, special cable-supported bridges like cable-stayed bridges and extradosed bridges are being adopted in earnest with technical specifications. The cable supported bridge is recognized as one of the indices of technology in civil engineering field, and thus it is being adpoted with a sense of rivalry in countries with advanced technology in railway engineering. In this paper, to apply the top-level cable-supported bridge technology to the domestic high-speed line up to 400㎞/h by establishing the technical specifications on cable-supported bridges including span length, the requirements for securing the dynamic stability and running safety of high speed train are analyzed through case studies for domestic and foreign cases.

발생원별에 따른 PAHs 배출특성

박찬구,윤중섭,김민영,손종열,모세영 한국대기환경학회 2004 한국대기환경학회지 Vol.20 No.3

The results of individual PAH source profiles that can be applied to receptor model are as follows. The sum of 16 PAH concentrations was 391.41 ng/S㎥ in a tunnel. Phenanthrene was the most abundant compound among 16 PAH, and then pyrene, fIuoranthene, anthracene, and naphthalene can be seen in elevated contents. 11,056.61 ng/S㎥ of 16 PAH concentrations in BC oil boiler was two times higher than 6,582.57 ng/S㎥ of those in LNG boiler. Naphthalene was the most abundant compound in both facilities. Phenanthrene, anthracene. and acenaphthylene were the second dominant compound group in order from both facilities. BC oil boiler had relatively high concentration of pyrene compared to LNG boiler that had high concentration of fluorene and did not detect pyrene. The sum of 16 PAH concentrations emitted from MSW incinerators after APCD (air pollution control device) was three times higher than those from MSW incinerators bcfore APCD. However, the concentrations of more than 4-ring PAH compounds (e.g., benzo (a)anthracene) before APCD were higher than those after APCD. This fact implies that PAHs generated by combustion process are eliminated in APCD and they are continuously produced in stack or atmosphere by PAHs precursors.

농업인의 농업생산 역량 진단도구 개발

김진모,정철영,주대진,길대환,박종선,송민철 한국농업교육학회 2011 농업교육과 인적자원개발 Vol.43 No.4

급격하게 변화하는 환경에 대응할 수 있는 전문농업인을 체계적으로 육성해야하는 현 시점에서 농업인에게 실제적으로 요구되는 능력 및 역량을 표준화하고 농업인의 능력수준을 체계적으로 파악해야 할 필요성이 제기되고 있다. 이에 따라 본 연구는 농업생산 역량 진단도구 개발을 목적으로 하였다. 이를 위해 문헌 고찰, 전문가 협의회, 전문가 자문, 설문조사 등의 방법을 활용하여 23개 품목별 농업인의 성장단계 및 성취기준을 설정하고, 농업생산 역량모델을 개발한 후 이를 토대로 역량 진단도구를 개발하였다. 농업생산 역량모델은 직무분석 접근방법을 기반으로 하여 직무과제 분석을 실시하였고, 그 결과에 따라 역량 및 행동지표를 개발하였다. 역량 진단도구는 자가진단 방식으로 현재수준을 측정하도록 하였으며, 전문가 패널을 통해 설정한 개발목표 및 중요도와 비교할 수 있도록 구성하였다. 이 연구를 통해 도출된 주요 결과는 다음과 같다. 첫째, 농업인의 성장단계를 초보자, 준전문가, 전문가의 3단계로 규정하였다. 둘째, 농업인의 성장단계별 성취기준을 품목별로 설정하였다. 셋째, 23개 품목별 직무과제 분석을 통해 농업생산 역량모델을 개발하였다. 넷째, 품목별 역량모델의 행동지표를 활용한 문항개발을 통해 농업생산 역량 진단도구를 개발하였다. There are increasing needs to systematically foster professional farmers who can cope with the rapidly changing environment. Therefore, it is important to set competency standards for farmers and to systematically measure levels of farmers competencies. For this reason, the purpose of this study was to develop an assessment tool for farmers agriculture production competency. Through a literature review, council meetings, experts consultation and survey, we set developmental stages and achievement standards of farmers for 23 farming products, developed an agricultural production competency model, and finally developed an agricultural production competency assessment tool. A competency model for agricultural production was developed using job and task analysis, and competency behavioral indicators were developed according to the job analysis result. A competency assessment tool was made to measure farmers’present state of competency level by a self-assessment method and was designed to be able to compare themselves with developmental objectives and level of importance set by the expert panel. The result of this study is as follows: 1) Developmental stages of farmers were determined as three levels: beginners, semi-professionals and professionals; 2) Achievement standards for each developmental stage of farmers were set; 3) Agriculture production competency model was developed using job and task analysis for 23 farming products; 4) Assessment tool for agriculture production competency was developed by developing questionnaire items with competency behavioral indicators.

소아에서의 Nd : YAG Laser를 이용한 치은착색제거술 YAG Laser in children

모경희,박헌동,박종휘,김효석,정현구,설재헌,이병채 조선대학교 구강생물학연구소 2003 口腔生物學硏究 Vol.27 No.1

Melanin is normally found in the skin of all people, and normal pigmentation of the intraoral tissues is a relative frequent finding. Gingival hyperpigmentation may cause esthetic problems and embarrassment, especially in patients with a gummy smile. Melanin pigmentation is related to etiologic factor such as hormon, systemic factor, drug, smoking and gingival inflamation. Depigmentation procedure can be Performed by gingival epithelium removing procedure, gingivectomy, free gingival graft, laser therapy, dry ice, Vitamin C and phenol-alcohol method. We could obtain favorable esthetic results by procedures such as Nd: YAG laser. The Nd:YAG laser was set at 4 watt, 50mJ, 80 pulse per second. The procedures were performed with contact mode in all pigmented areas by using a handpiece with a 320㎛ diameter fiber optic. Ablation of the gingival hyperpigmented gingiva appeared healthy, pink, and firm. No recurrence of hyperpigmentation had been found in 6 months of follow-up.

37% 인산 부식제에 의해 발생한 안면피부의 화학 화상

박종현,신혜진,박세희,김진우,조경모 대한치과보존학회 2009 Restorative Dentistry & Endodontics Vol.34 No.1

복합레진 수복을 위해 상아질에 total-etch adhesive system을 적용할 경우. 37% 인산 산부식제가 널리 사용되고 있다. 37% 인산은 매우 강력한 부식제로 구강점막이나 안면피부와 접촉되었을 때 심각한 해로운 효과가 발생될 수 있다. 이 증례 보고에서는 복합레진 수복과정에서 사용된 인산 산부식제에 의해 안면피부에 발생된 의원성 화학적 화상을 보고하고자 한다. 산부식제에 의한 화학적 화상은 산부식제를 부주의하고 부적절하게 사용함으로 발생될 수 있으며, 이러한 의원성 손상을 방지하기 위해서는 산부식과 수세과정 후 산부식제가 완전히 제거되었는지를 확인하여야하며 복합레진 수복 시 러버댐이나 적절한 격리 기구를 사용하는 것이 필요할 것이다. 화상이 발생하였다면 적절한 응급처치 후 피부과로 의뢰하는 것이 필요할 것이다. When we use the total-etch dentin adhesive system for composite resin restorations. gel or liquid acid etchant such as 37% phosphoric acid is commonly used. Thirty seven percentage phosphoric acid is very powerful erosive agent. and can cause severe harmful effects when it contacts with an oral mucosa and facial skin. This case describes iatrogenic chemical burn on facial skin caused by phosphoric acid which was happened during composite resin restorative procedure. Chemical burn by acid etchant can be evoked by careless handling of remnant and syringe. In order to prevent these iatrogenic injuries, we should check the complete removal of the etching agent both in intra and extra-oral environments after etching and rinsing procedure and it is necessary to use of the rubber dam or isolation instruments. If accidental burn were occurred, immediate wash with copious water. And bring the patient to the dermatologist as soon as possible.