Prediction of Retained Austenite Fraction in Quenching-and-Partitioning (Q&P) Steels Using the Gibbs Energy Balance Approach

Seong Hoon Kim,Ji Hoon Kim,Jae Hoon Lee,Dong‑Woo Suh,Jae Sang Lee 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.9

Prediction of retained austenite fraction is quite important in designing advanced high strength steels since retained austeniteis the source of transformation-induced plasticity. The present study investigates the phase constitution of a medium-carbonQ&P steel by comparing various approaches to the transformation stasis of bainitic ferrite and applying them to the partitioningprocess. Among them, the modified GEB approach gave the best agreement with the experimental observation, includingthe effects of heat-treatment condition and chemical composition on phase constitution. This indicates phase transformationduring partitioning can be effectively described by the physics of Gibbs energy balance approach.

표면근전도와 적외선체열촬영을 이용한 요통의 평가

이강진,최인성,이소영,한재영,이삼규,채홍재,이성과,문재동 대한산업의학회 2001 대한직업환경의학회지 Vol.13 No.3

목적 : 요통환자에서 요통의 유무와 강도를 평가하고자 표면근전도를 이용하여 근육 활동성의 차이를 검증하였고 적외선체열촬영을 이용하여 제표면 온도의 변화를 측정하였다. 방법 : 요통환자군 16명과 대조군 16명에 대하여 요부에 부착한 표면전극에서 얻은 근전도 신호와 적외선체열촬영 결과를 비교하였다. 교란요인의 영향을 배제하기 위하여 연령과 성별 그리고 비만도에 따라 정상 대조군과 요통환자군을 짝짓기하여 각각 16명씩 선정하였다. 결과 : 정적표면근전도 실시 결과 우측의 경우 중앙값이 요통환자군에서 198.1 ㎶, 정상대조군에서는 161.3 ㎶로 통계적으로 유의한 차이가 있었고(p<0.01), 좌측은 요통환자군에서 194.2 ㎶, 정상대조군에서 180.5 ㎶로 유의한 차이는 없었다. 동적표면근전도 실시 결과 재신전시와 굴곡시 근전위의 비가 우측의 경우 요통환자군에서 중앙값이 1.12였고 정상 대조군은 1.39로서 두 군간에 유의한 차이가 있었고(p=0.027), 좌측의 경우도 요통환자군에서는 1.08이었고 정상 대조군에서는 1.21로 유의한 차이가 있었다(p=0.036). 적외선체열촬영결과 ΔT가 0.5 ℃ 이상의 차이가 있을 때 이상이 있는 것으로 정하면, 요통환자군에서는 16명 모두 이상자로 판정되었고, 정상 대조군에서는 16명중 3명이 이상자로 판정되어 민감도는 100 %, 특이도는 81.3 % 였다. 표면근전도를 이용한 요통의 진단은 민감도가 78.6 %이고 특이도가 72.2 %였으며, 적외선체열촬영은 민감도가 100 %였고 특이도가 87.5 %였다. 결론 : 이러한 결과로 볼 때 표면근전도 검사법과 적외선체열촬영은 요통을 간접적으로 평가하는데 도움이 되는 검사법이며, 적외선체열촬영이 표면근전도검사법에 비하여 보다 정확한 검사법으로 판단된다. Objectives : We studied the efficacy of surface electromyography(SEMG) and digital infrared theimographic imaging (DITI) in the assessment of low back pain both(LBP) Methods : We compared electromygraphic signals from electrodes placed in the lumbar area and the digital theimographic images in 16 LBPpatients and 16 control subjects. The LBP patients and the control subjects were matched for age, gender, and body mass index(BMI) to adjust for any confounding effects Results : In the static analyses of SEMG, median value was 198.1 ㎶ for the controls on the right side, and they were 194.2 ㎶ and 180.5㎶ on left side respectively. There was a statistically significant difference between the two groups on the right side(p<0.01), but not on the left side. In the dynamic analyses of the SEMG, the median values of the extension per flexion ratio of right side were 1.12 for LBP patients and 1.39 for controls. and those on the left side were 1.08 and 1.21 respectively. There were statistically significant differences in both sodes(p<0.05). The sensitivity and specificity were 100% and 81.3% in DITI, 78.6% and 72.2% in SEMG. Conclusions : These results indicate that SEMG and DITI are useful methods for indirect assessments of LBP, and that DITI is more sensitive and specific than SEMG.

사면의 안정도 해석을 위한 입체투영법

이성대,이철우,이동우,이성규 公州大學校 基礎科學硏究所 1996 自然科學硏究 Vol.5 No.-

암반 사면의 안정성을 해석하는데 입체투영기법을 이용하였다. 안정도에 영향을 미치는 요인으로는 절리의 경사, 암석의 밀도, 내부마찰각등이 있으나, 가장 중요한 요인은 절리면의 경사이다. 이 연구에서는 암석의 점착력은 무시하고 단지 내부마찰각과 절리의 주향 및 경사만을 이용하였다. 그 결과 입체투영도에서 나타나는 암반사면의 안정도는 이동력과 저항력의 상대적인 크기에 의하여 좌우되는 것으로 나타났다. 동시에, 지반진동에 의한 영향도 입체 투영기법으로 찾아낼수 있다는 것이 밝혀졌다. Stereographic projection technique was used to analyze rock slope stability. Strike and dip of joints, rock strength, and internal frictional angle are major factor on slope stability. Among them, the most important factor is strike and dip of joints. In stereographgic projection technique, only internal frictional angle, and strike and dip of joints were used to interprete slope stability. Cohesion of rock was not considered. It is suggested that the rock slope stability on stereographic projection depends upon only the differential stress between driving and resisting force. At the same time, Stereographic projection technique on seismic loading was proposed in this study.

GC/NPD를 이용한 다성분 잔류농약의 동시분석

김우성,이선화,김상엽,정동윤,김재이,이영자,이홍재,정성욱,박흥재 한국환경과학회 2003 한국환경과학회지 Vol.12 No.10

Pesticides were extracted from samples with 70% acetone and methylene chloride in order, and then cleaned up via open-column chromatography apparatus packed with fiorisil, and finally analyzed simultaneously the organophosphorus pesticides using GC/NPD, Ultra-2 and Ultra-1 fused silica capillary columns were used to separate and identify the products. Recovery of most analytes from soybean sample, taken from pesticide residues well, was greater than(80%) for all except(6) analytes. This method can simultaneously determine multiple pesticides with a high degree of accuracy and precision.

퇴행성 슬관절염 환자 평가 설문도구의 내적 신뢰도, 상관성에 관한 연구

류성룡,안경애,서병관,강중원,이상훈,이재동,최도영,김건식,이두익,이윤호 EAST-WEST MEDICAL RESEARCH INSTITUTE KYUNG HEE UNI 2005 東西醫學硏究所 論文集 Vol.2005 No.-

Objective : The aim of this study is to evaluate internal reliability and correlation among assessment instruments of knee OA. Methods : Data were obtained from 85 patients with knee OA. They were asked to answer VAS pain scale, two disease-specific questionnaires (WOMAC and LFI) and one instrument about health-related quality(KHAQ). Reliability was assessed using cronbach's alpha. Correlation was assessed by examining the pearson's correlation coefficients. Results : Cronbach's alpha of all Index except WOMAC stiffness subscale(.6679) exceeded the value of 0.70. A good correlation was obtained between WOMAC Subscale (especially Pain Subscale) and LFI (.726<cronbach's alpha<.791). Also, Correlation between KHAQ and two disease-specific questionnaires (WOMAC and LFI) was good(.612<cronbach's alpha<.662). Conclusions : All used instruments have good internal reliability. also, There are good correlation among them. The treatment of knee OA must be focused on health related quality. For this, we should use proper assessment instruments.

부신피질 자극호르몬 단독결핍 1례

박경식,이승현,최석영,박태규,이동화,이찬우,정성복,이인규 啓明大學校 醫科大學 1997 계명의대학술지 Vol.16 No.3

부신피질 자극호르몬 단독결핍은 국내에서 7례만이 보고된 희귀 질환이며 병인 및 경과 등 아직 불분명한 측면이 많다. 이는 질환지체의 희귀성도 있지만 치료후 자연경과에 대한 장기적인 추적검사가 이루어진 경우가 드물기 때문이기도 하다. 저자들은 비특이적인 전신증상을 주소로 내원한 폐경기후의 56세 여자 환자에서 자가면역질환의 증거없이 고프로릭틴혈증을 보인 부신피질 자극호르몬 단독결핍 1례를 경험하고 1년간의 부신피질호르몬 대치요법후 추적검사를 실시하였기에 문헌 고찰과 함께 보고하는 바이다. Isolated ACTH deficiency is a rare disorder which shows secondary adrenal insufficiency with normal states of other pituitary hormones. A 56-year-old postmenopausal woman complaining general weakness and intermittent mental confusion presented negligible serum cortisol and ACTH level with hyperprolactinemia and mild hyponatremia. Rapid ACTH stimulation test did not show significant increase of serum cortisol level. Combined pituitary stimulation test showed negligible response of cortisol and ACTH, and slightly decreased response of prolactin and gonadotropin. But the responses of TSH and GH were normal. There was no evidence of organic pituitary of hypothalamic lesion in brain MRI and antithyroid autoantibody was not detected in serum. After receiving 12 months of glucocorticoid replacement therapy, she skipped the medicine for 3 weeks and we performed follow-up endocrinologic tests. Serum ACTH and cortisol level was also negligible and prolonged ACTH simulation test showed normal response of serum cortisol. CRF stimulation test showed no response of serum ACTH. Basal prolactin level was decreased to near normal and combined pituitary stimulation test showed normal response of prolactin with slightly blunted response of TSH and GH. We concluded that the case was nonautoimmune origined isolated ACTH deficiency which was accompanied by hyperprolactinemia and resultant deficiency of gonadotropin, so we report this case with review of literatures.

우리나라 지역 직업성질환 감시체계의 현황과 전망

임종한,장성실,김성아,문재동,채창호,홍윤철,김수영,김진석,김영욱,한상환,이혜숙,원종욱,송동빈,하은희,강성규 대한산업의학회 2001 대한직업환경의학회지 Vol.13 No.2

기존의 특수건강진단과 작업환경측정을 통한 직업병 관리가 진폐증, 소음성난청 등의 소수 특정질환에 국한되고 실제 직업병 발생 규모 파악이나 신종 직업병의 발견에 한계를 보인다는 사실은 산업의학전문가들 사이에서도 공감을 이루고 있다. 미국과 영국 등에서의 직업성질환 감시체계에 대한 경험은 우리 나라의 직업성질환 감시체계 구축에도 새로운 자극제가 되면서, 1998년이후 인천, 대전, 여천, 구미, 부울경 지역에서 지역 직업성질환감시체계를 산업보건관리의 중요한 시스템으로 구축하려는 노력이 확산되고 있다. 새로이 구축되어지는 이들 지역 직업성질환 감시체계는 감시하고자 하는 대상질환, 활용 가능한 인적자원 및 자료원, 지역 의료체계의 특수성 등에 따라서 목적과 방법을 달리하면서 독특한 형태로 발전을 하고 있다. 각 지역단위 감시체계들이 그 상황에 맞게 독특한 목적과 전략들을 발전 시키면서도, 향후 발전할 국가적인 차원의 직업성질환 감시체계 구축을 위하여 직업성질환 감시의 기본 전략 등을 공유하는 등의 노력이 필요하다. 환례 정의 및 기본적인 등록 서식의 공유, 직업성질환 감시 자료원의 발굴, 공동의 정보 네트워크 및 직업성질환 감시 데이터베이스 구축 등 직업성질환 감시활동을 지원하기 위한 여러 기초 인프라 구축에 힘을 모아야 할 것이다. 우리 나라에서 직업성질환 감시체계를 성공적으로 구축하기 위해서는 수집된 자료의 질 관리를 위한 직업성질환 감시의 원칙 제정과 감시 전략의 공유 등이 필요하며, 전국적인 직업성질환 감시체계의 하부구조라고 할 수 있는 지역감시체계의 기초 토대 마련과 강화작업이 절실하게 필요하다.

퇴행성 슬관절염 환자의 증상 중증도 지표와 DITI의 상관성 연구

서병관,류성룡,강중원,안경애,이재동,최도영,김건식,이두익,이윤호,이상훈 EAST-WEST MEDICAL RESEARCH INSTITUTE KYUNG HEE UNI 2005 東西醫學硏究所 論文集 Vol.2005 No.-

Objectives : To investigate the applicability of thermography as severity measurement in the patients with osteoarthritis (OA) of the knee. Methods : Data were obtained from 80 patiens with OA of the knee. They were asked to answer two disease-specific questionnaire (Western Ontario and McMaster Universities (WOMAC) OA index, Lequesne's Functional Index (LFI)), one generic instrument (Korean Health Assessment Questionnaire (KHAQ)), VAS in order to assess the severity of disease, quality of life, degree of pain and taken thermography in standardized environment. Results : The thermal difference between ipsilateral side and contralaterla side of lateral aspect of knee was correlated with that of medial aspect of knee, and the thermal difference of anterior thigh was correlated with that of lateral, medial aspect of knee and patella region. Age, duration of disease, duration of morning stiffness, sex, crepitus, and painful side of knee were not correlated with the thermal differences of each region. LFI, WOMAC, WOMAC pain subscale, WOMAC stiffness subscale, WOMAC physical function, KHAQ,, VAS were not correlated with the thermal differences of each region. Conclusion : Further study on the thermography on OA of the knee in population with appropriate severity grade and the standardization of analysis of thermographic data were recommended.

퇴행성 슬관절염에 대한 제통단의 안정성과 효능 임상연구

서병관,류성룡,강중원,안경애,이상훈,최도영,김건식,이두익,이윤호,이재동 EAST-WEST MEDICAL RESEARCH INSTITUTE KYUNG HEE UNI 2005 東西醫學硏究所 論文集 Vol.2005 No.-

Objectives : In order to investigate the efficacy and safety of the newly developed herbal medicine Jetongdan, a placebo-controlled randomized clinical trial of patients with osteoarthriotis of the knee was undertaken. Methods : Data were obtained from 80 patients with OA of the knee. After the enrollment, they were asked to answer a disease-specific questionnaire (Western Ontario and McMaster Universities (WOMAC) OA index) and analyzed with the erythrocyte sedimentation rate (ESR) in order to evaluate the efficacy of Jetongdan, and analyzed for aspartate transaminase (AST) level, alanine transminase (ALT) level, blood urea mitrogen (BUN) level, and creatinine (Cr) level in order to evaluate the safety of Jetongdan. Results : The liver function and renal function did not deteriorate after treatment with Jetongdan. Composite WOMAC score and physical function subscale was improved, but pain subscale, stiffness subscale, and ESR were not improved by Jetongdan. This was possibly because the baseline characteristics of the two groups were not homogenized after randomization. Conclusions : Jetongdan could be a promising treatment option for osteoarthritis of the knee. Further study in a larger population with appropriate severity grades is recommended.

제통단이 퇴행성 슬관절염 환자의 삶의 질에 미치는 영향

서병관,류성룡,강중원,우현수,이상훈,이재동,최도영,김건식,이두익,이윤호 EAST-WEST MEDICAL RESEARCH INSTITUTE KYUNG HEE UNI 2005 東西醫學硏究所 論文集 Vol.2005 No.-

Objectives : to evaluate the effects of Jetongdan, the newly developed herbal medicine, on the quality of life in patients with osteoarthritis of knee Methods : Placebo-controlled, randomized clinical trial on the 80 patients with osteoarthritis of the knee was fulfilled. After enrollment, they took medication as they enrolled. And they were asked to answer the questionnaires (Korean Health Assessment Questionnaire (KHAQ), Lequesne's functional index (LF1), visual analogue scale (VAS)) and analysed with the erythrocyte sedimentation rate (ESR) at baseline, after 4 weeks and 8 weeks of medication. Results : Total KHAQ score, some categories of KHAQ like hygiene, activities were significantly improved after 8 weeks of medication. And the change of the KHAQ score was significantly correlated with the change of VAS. But LFI, VAS, ESR level was not significantly improved, and it was considered because of the short medication period and small size of study population. Conclusion : In conclusion, Jetongdan could improve the health-related quality of life in patients with osteoarthritis of knee. Further study in the large population, in long period were recommended.