Microstructure and High Temperature Oxidation Property of Fe-Cr-B Based Metal/Ceramic Composite Manufactured by Powder Injection Molding Process

Yeun‑Ah Joo,Young‑Kyun Kim,윤태식,Kee‑Ahn Lee 대한금속·재료학회 2018 METALS AND MATERIALS International Vol.24 No.2

This study investigated the microstructure and high temperature oxidation property of Fe–Cr–B metal/ceramic compositemanufactured using powder injection molding process. Observations of initial microstructure showed a unique structurewhere α-Fe and (Cr, Fe)2B form a continuous three-dimensional network. High temperature oxidation tests were performedat 900, 1000 and 1100 °C, for 24 h, and the oxidation weight gain according to each temperature condition was 0.13, 0.84and 6.4 mg/cm2, respectively. The oxidation results according to time at 900 and 1000 °C conditions represented paraboliccurves, and at 1100 °C condition formed a rectilinear curve. Observation and phase analysis results of the oxides identifiedCr2O3and SiO2at 900 and 1000 °C. In addition to Cr2O3and SiO2,CrBO3and FeCr2O4formed due to phase decompositionof boride were identified at 1100 °C. Based on the findings above, this study suggested the high temperature oxidationmechanism of Fe–Cr–B metal/ceramic composite manufactured using powder injection molding, and the possibility of itsapplication as a high temperature component material was also discussed.

뇌사환자의 갑상선 기능, 전신대사 및 중증도에 관한 연구

이영주,정금희,왕희정,문봉기,한연희,이영석 아주대학교 의과학연구소 1999 아주의학 Vol.4 No.1

Background and Objectives : Brain death may lead to hormonal depletion, metabolic derangement and multiple organ dysfunction. We have carried out present study to examine the effects of brain death on the thyroid function, metabolic indices, and the severity scoring systems. Methods : 13 adults patients admitted for organ donation or brain death evaluation were examined after brain death was confirmed. Thyroid hormones measured were .thyroid stimulating hormone (TSH), triiodothyronine (T3), thyroxine (T4), and free thyroxine (FT4). The metabolic indices measured were arterial ketone body ratio (AKBR), lactic acid (LA), and base defiat (BD). as for reference to the severity scoring systems, APACHE Ⅲ and multiple organ failure score (MOFS) were assessed on the day of brain death confirmation. Arterial blood was drawn for all measurements. Results : As for the thyroid function, there were significant decreases in T3 (40.48±20.96 ng/dL) and T4 (3.47±2.15 ㎍/dL), but no significant change in FT4 (0.75±0.31 ng/dL) and TSH (1.12±1.37 uIU/mL) compared to the normal range. Significant decreases in AKBR (0.39±0.31) and BD (-9.46±5.83 m㏖/L), and significant increase in LA (2.57±2.46 m㏖/L) In metabolic indices, were shown, as for severity scoring systems, APACHE Ⅲ score (101.54±19.41) and MOF score (9.11±2.57) indicated a high mortality. There were significant correlation between thyroid hormones (r=0.565 -0.781) but no correlation among other indices. Also, significant inverse correlations were shown between base deficit and lactic acid (r=-0.660), APACHE Ⅲ score (r=-0.726) and MOF score (r=-0.604). The highest correlation was observed between APACHE Ⅲ score and MOF score (r=0.851). Conclusions : As for the thyroid function, significant decrease in T3 and T4, and almost normal range of FT4 and TSH imply the euthyroid sick syndrome. Abnormal finding of the metabolic parameters indicates an inhibition of the aerobic metabolic rate of the body as a whole. And the severity scoring parameters are compatible with high mortality.

식이섬유가 고콜레스테롤혈증 흰쥐의 지질농도에 미치는 영향

김명주,장주연,이미경,박지윤,박은미 한국식품영양학회 1999 韓國食品營養學會誌 Vol.12 No.1

DAN 코딩 기법과 웨이브렛 소속함수를 사용한 혼돈 시계열 시스템의 퍼지모델링

이연우,유진영,주영훈 국립7개대학공동논문집간행위원회 2003 공업기술연구 Vol.3 No.-

In this paper, we propose a new method about wavelet-based fuzzy modeling using a DNA coding method. DNA coding techniques is known that expression of knowledge is various than Genetic Algorithm(GA) usually by made optimization technique because done base in structure of biologic DNA and optimization performance is superior. The proposed method make fuzzy system model in wavelet transform and equivalence relation after identification with coefficient of wavelet transform using a DNA coding techniques. Also, can get fuzzy model effectively of nonlinear system using advantage of strong wavelet transform about function that have sudden change. In this paper, in order to demonstrate the superiority of the proposed method compared with GA.

에탄올 중독된 흰쥐의 간조직 중 지질대사에 미치는 셀렌과 메티오닌의 영향

김명주,이미경,장주연,박은미 한국식품영양학회 1999 韓國食品營養學會誌 Vol.12 No.1

산업체 급식소에서 생산직 근로자에게 제공되고 있는 음식의 적정 분량을 제시하기 위해 목포지역 생산직 근로자 240명을 대상으로 섭취량 측정과 설문지를 이용한 만족도 평가를 실시하였다. 조사대상 근로자의 연령은 30∼39세가 57.1%, 학력은 대부분 고졸이었으며, 건강상태는 52.1%가 건강하다고 하였다. 근로자의 좋아하는 식사의 형태는 한식이었고, 식품을 선택할 때 가장 중요하게 생각하는 것은 맛으로 나타났으며, 식사의 가치관은 조사대상 근로자의 37.1%가 공복을 채우는 것이라고 대답해서 생리적 욕구충족에 가치를 둔 비율이 가장 높았다. 산업체 급식소에서 제공된 음식의 섭취량과 섭취율은 밥류 238g(98.4%), 국류 212g(82.7%), 찌개류 230g(77.2%), 볶음류 40g(80.7%), 조림류 60g(83.5%), 무침류 42g(72.3%), 김치류 51g(75.9%), 일품요리류 406g(77.7%), 구이류 51g(72.6), 부침류 48g(48.7%)였다. 섭취량에 대한 만족도 평가 결과, 섭취량에 대해서 두 비교군 거의 모두가 '적은 양'이라고 대답하였다. 섭취량에 대한 만족도 평가를 기초로 음식의 적정량에 대해 밥류 240∼270g, 국류 270g, 찌개류 310g, 볶음류 60g, 조림류 75g, 무침류 76g, 김치류 67g, 일품요리류 470g, 구이류 80g, 부침류 50g으로 제시할 수 있다. The purpose of this study is to set up a appropriate portion by consumed size of food in industry food-service operation. The results were summarized as follows: 51.7% of the subjects were 30 to 39 years old, 83.3% of them had highschool education. They represented that taste of food was the most important point in food intake. Individual consumption sizes for physical workers in the industry foodservice were cooked rices 238g, soups 212g, pot stewes 230g, stir fries 40g, stewes 60g, fresh and boiled salad 42g, kimchies 51g, one course dishies 406g, grills 51g, meunieres 47g. Properly portioned meal sizes for physical workers based on a statistical data showed cooked rices 240∼270g, soups 270g, pot stewes 310g, stir fries 60g, stewes 75g, fresh and boiled salads 76g, kimchies 67g, one course dishies 470g, grills 80g and meunieres 50g in the foodservice industry.

임플란트 hexagon 높이에 따른 임플란트와 주위 조직의 응력분포 평가

박성재,김주현,김소연,윤미정,고석민,허중보 대한치과보철학회 2012 대한치과보철학회지 Vol.50 No.1

PURPOSE. To analyze the stress distribution of the implant and its supporting structures through 3D finite elements analysis for implants with different hexagon heights and to make the assessment of the mechanical stability and the effect of the elements. MATERIALS AND METHODS. Infinite elements modeling with CAD data was designed. The modeling was done as follows; an external connection type ∅4.0 mm×11.5 mm OsstemUSII (Osstem Co., Pusan, Korea) implant system was used, the implant was planted in the mandibular first molar region with appropriate prosthetic restoration, the hexagon (implant fixture’s external connection) height of 0.0, 0.7, 1.2, and 1.5 mm were applied. ABAQUS 6.4 (ABAQUS, Inc., Providence, USA) was used to calculate the stress value. The force distribution via color distribution on each experimental group’s implant fixture and titanium screw was studied based on the equivalent stress (von Mises stress). The maximum stress level of each element (crown, implant screw, implant fixture, cortical bone and cancellous bone) was compared. RESULTS. The hexagonal height of the implant with external connection had an influence on the stress distribution of the fixture, screw and upper prosthesis and the surrounding supporting bone. As the hexagon height increased, the stress was well distributed and there was a decrease in the maximum stress value. If the height of the hexagon reached over 1.2 mm, there was no significant influence on the stress distribution. CONCLUSION. For implants with external connections, a hexagon is vital for stress distribution. As the height of the hexagon increased, the more effective stress distribution was observed. 연구 목적: 본 연구는 hexagon 높이에 따른 임플란트 각 부위와 주위 지지조직의 응력분포를 3차원 유한요소 해석을 통해 평가하여 hexagon 높이가 기계적 안정성에 미치는 영향을 평가하고자 시행되었다. 연구 재료 및 방법: 외측 연결 형태의∅L4.0 mm×11.5 mm USII (Osstem Co., Pusan, Korea) 임플란트 시스템을 이용하여 하악 제 1대구치 부위에 임플란트를 식립하여 보철 수복한 경우를 연구 모델로 가정하고 임플란트 고정체의 외측 연결부인 hexagon의 높이를 각각 0.0 mm, 0.7 mm, 1.2 mm, 1.5 mm로 적용한 CAD data를 유한요소 모형화하였다. ABAQUS 6.4 (ABAQUS Inc., Providence, RI, USA)를 이용하여 산출된 응력 값 중에서 등가응력을 기준으로 각 요소(상부 치관, 지대주 나사, 고정체, 치밀골, 해면골)에서 나타나는 최대 응력 값을 비교 하였다. 결과:외측 연결을 갖는 임플란트의 hexagon의 높이는 고정체, 지대주 나사, 상부 보철물 그리고 주위 지지골에 대해 응력 분산에 영향을 주었다. Hexagon의 높이가 증가할 수록 임플란트의 응력 분산은 더 잘 이루어졌으며, 최대 응력 값의 감소를 보였다. Hexagon의 높이가 1.2 mm 이상이 되면 응력 분포에 더 이상 크게 기여하지 않았다. 결론: 외측연결을 갖는 임플란트에서 hexagon은 응력 분산에 필수적인 요소이며 그 높이가 증가할수록 더욱 효과적인 응력의 분산이 나타났다.

한국인 만성 긴장형두통 환자에서 바이오피드백을 활용한 자율적 이완훈련의 효과

강은호,안주연,구문선,박주언,유범희 大韓神經精神醫學會 2008 신경정신의학 Vol.47 No.3

Objectives : We aimed to evaluate the efficacy of biofeedback-assisted autogenic training for chronic tension-type headache, and to determine the relationship among the changes in electromyography (EMG) activity, headache activity, and mood states according to the psychophysiological treatment. Methods : Chronic tension-type headache patients aged from 20 to 40 years (n=35) were randomized to the treatment group receiving biofeedback-assisted autogenic training (8 sessions) or the monitoring-only control group. EMG activities, headache index, and various psychological variables were examined. Results : We found greater treatment response rate (≥50% reduction in headache index) in patients with biofeedback-assisted autogenic training than in the monitoring group (61% vs. 18% ; χ²=6.882, df=1, p=0.01). There were no significant changes in the mean values of the pretreatment EMG activities across the sessions m either group (all p’s>0.1). Mood states including anxiety and depression improved over time in the both groups, with the improvements being more prominent in the treatment group. Moreover, the reduction in depression level predicted treatment outcome in terms of headache index (95% confidence interval : 0.272-0.966, p=0.039). Conclusion : These results show that biofeedback-assisted autogenic training is effective for the treatment of chronic tension-type headache in a Korean population. Changes in mood states may be closely associated with the clinical outcome in the treatment of chronic tension-type headache using biofeedback-assisted autogenic training.

mGA를 이용한 웨이블렛 퍼지 모델링

유진영,이연우,주영훈 국립7개대학공동논문집간행위원회 2002 공업기술연구 Vol.2 No.-

In this paper, we propose a new approach to Wavelet Fuzzy Modeling using messy genetic algorithm(mGA). mGA has more effective and adaptive structure than sGA with respect to using the changeable-length string. We build a fuzzy system model which is equivalent to the wavelet transform after identifying the coefficients of wavelet transform. We can obtain an accurate system model with a small number of coefficients due to the energy compaction property of the wavelet transform. And it means that we can construct a fuzzy system model with a small number of rules. By the conventional fuzzy modeling method, a problem might arise that a function with abrupt changes can hardly be modeled precisely. Hence, we present a solution to this problem by the advantageous property of the wavelet transform. We demonstrate the superiority of our proposed fuzzy system modeling method over the previous results by modeling a highly nonlinear function.

에탄올성 간손상 흰쥐의 유해산소 생성효소계에 미치는 칡 추출물의 영향

조수열,김명주,박은미,박지윤,장주연 한국노화학회 2001 한국노화학회지 Vol.11 No.1

한국인 환자에서 Vancomycin의 집단약동학 (Population Pharmacokinetics)에 관한 연구

유경상,배균섭,이주연,조주연,장인진,신상구,신완균 大韓臨床藥理學會 1998 臨床藥理學會誌 Vol.6 No.2