후열처리에 따른 Cu-NiCrBSi 이종 레이저 클래드부의 미세조직 및 기계적 성질 변화

김경민,정예선,심아진,박원아,박창규,천은준,Kim, Kyeong-Min,Jeong, Ye-Seon,Sim, Ahjin,Park, Wonah,Park, Changkyoo,Chun, Eun-Joon 한국재료학회 2020 한국재료학회지 Vol.30 No.9

For surface hardening of a continuous casting mold component, a fundamental metallurgical investigation on dissimilar laser clads (Cu-NiCrBSi) is performed. In particular, variation behavior of microstructures and mechanical properties (hardness and wear resistance) of dissimilar clads during long-term service is clarified by performing high-temperature post-clad heat treatment (temperature range: 500 ~ 1,000 ℃ and isothermal holding time: 20 ~ 500 min). The microstructures of clad metals (as-clads) consist of fine dendrite morphologies and severe microsegregations of the alloying elements (Cr and Si); substrate material (Cu) is clearly confirmed. During the post-clad heat treatment, the microsegregations are totally homogenized, and secondary phases (Cr-based borides and carbides) precipitated during the short-term heat treatment are also almost dissolved, especially at the heat treatment conditions of 950 ℃ for 500 min. Owing to these microstructural homogenization behaviors, an opposite tendency of the surface mechanical properties can be confirmed. In other words, the wear resistance (wear rate) improves from 4.1 × 10^-2 ㎣/Nm (as-clad condition) to 1.4 × 10^-2 ㎣/Nm (heat-treated at 950 ℃ for 500 min), whereas the hardness decreases from 453 HV (as-clad condition) to 142 HV (heat-treated at 950 ℃ for 500 min).

Fabrication and Characterization of an Anodic Aluminum Oxide Template with Variations in the Anodization Solution for pH Sensors

Jo, Ye-Won,Lee, Sung-Gap,Yeo, Jin-Ho,Kim, Kyeong-Min American Scientific Publishers 2016 Journal of Nanoscience and Nanotechnology Vol.16 No.11

<P>In this study, an electrolyte-dielectric-metal (EDM) device incorporating a high-k (high dielectric constant) Al2O3 sensing template from porous anodic aluminum-oxide (AAO) was fabricated through a two-step anodizing process for pH detection. In order to change the morphologies of the AAO template, the anodization solution was varied by controlling the electrolyte. Getting the AAO template having a structure through this experiment was EDM measure the pH sensitivity changes according to the surface area. AAO templates were characterized by X-ray diffraction and field-emission scanning electron microscopy (FE-SEM). The anodic aluminum oxide template for pH sensors went through the following steps: 1st anodizing step at 90 V for 6 h (0.3 M, H3PO4); 2nd anodizing step at 90 V for 1 min (H3PO4 0.3 M); and pore widening for 30 min. The device displayed a good sensitivity of 54.2 mV/pH.</P>

산업현장 추락에 대한 기계학습 알고리즘 기반의 다집단 분류

구범모(Bum Mo Koo),김종만(Jong Man Kim),남예진(Ye Jin Nam),성동진(Dong Jin Sung),심재우(Jae Woo Shim),양수민(Su Min Yang),김영호(Young Ho Kim) 대한기계학회 2022 大韓機械學會論文集A Vol.46 No.3

본 연구에서는 웨어러블 관성센서를 사용하여 산업현장 추락에 대한 기계학습 기반의 다집단 분류를 시도하였다. 20명의 건강한 성인 남성을 모집하였으며, 15가지 non-FFH 동작과 5가지 low-hazard-FFH 동작 그리고 한 가지 high-hazard-FFH 동작을 3회씩 반복 측정하였다. 5개의 기계학습 기법(SVM, k-NN, LDA, QDA, MLP)에 대하여 two-class 분류성능과 three-class 분류성능을 비교하였다. 분석 결과 SVM이 two-class 분류와 three-class 분류에서 각각 99.5%와 98.2%의 가장 높은 정확도를 보였다. 또한, 세 가지 전처리 기법들(SMOTE, min-max 정규화, univariant feature selection) 역시 알고리즘 성능 향상에 기여함을 볼 수 있었다. In this study, a multi-class classification of industrial fall from height (FFH) based on machine learning was tried using a wearable inertial sensor. Twenty healthy adult males were recruited for the experiment. The experiment protocol consisted of 15 non-FFH, five low-hazard-FFH, and one high-hazard-FFH. Each motion was conducted three times repeatedly. Two-class classification performance and three-class classification performance were compared for five different machine learning techniques (SVM, k-NN, LDA, QDA, and MLP). As a result, SVM showed the highest accuracy of 99.52% and 98.25% in two-class classification and three-class classification, respectively. In addition, the three preprocessing techniques (SMOTE, min-max regularization, and univariant feature selection) contributed to the improvement of algorithm performance.

Effects of electroacupuncture on oxaliplatin-induced neuropathic cold hypersensitivity in rats

Moon, Hak Jin,Lim, Bong-Soo,Lee, Dae-Il,Ye, Min Sook,Lee, Giseog,Min, Byung-Il,Bae, Hyunsu,Na, Heung Sik,Kim, Sun Kwang Springer-Verlag 2014 JOURNAL OF PHYSIOLOGICAL SCIENCES Vol.64 No.2

This study investigated whether and how electroacupuncture (EA) attenuates cold hypersensitivity (allodynia) in a rat model of oxaliplatin-induced neuropathic pain. Cold allodynia [evaluated by immersing the tail into cold water (4 A degrees C) and measuring the withdrawal latency] was induced 3 days after an oxaliplatin administration (6 mg/kg, i.p.). EA stimulation (2/100 Hz, 0.3-ms pulse duration, 0.2-0.3 mA) was delivered to ST36 acupoint or non-acupoint for 20 min. Low-frequency (2 Hz) EA at ST36 relieved cold allodynia more effectively than high-frequency EA at ST36 or low-frequency EA at non-acupoint. Naloxone (opioid antagonist, 2 mg/kg, i.p.) completely blocked such EA-induced anti-allodynia, whereas phentolamine (alpha-adrenergic antagonist, 2 mg/kg, i.p.) did not. Moreover, plasma beta-endorphin levels significantly increased right after the end of EA and subsequently decreased. These results indicate that low-frequency EA at ST36 in rats has a marked relieving effect on oxaliplatin-induced cold allodynia that is mediated by the endogenous opioid, but not noradrenergic, system.

대구광역시 장애인의 의료이용양상과 결정요인

예민해,최병렬,감신,이희봉,심길택,이상수 한국건강관리협회 1998 건협 Report Vol.1 No.-

여수국가산업단지 인근 지역 대기오염물질 농도에 영향을 미치는 요인분석

김민영,변정훈,이영훈,이건영,한지은,이예림,임지현,장봉기 순천향대학교 기초과학연구소 2022 순천향자연과학연구 논문집 Vol.28 No.1,2

Eight monitoring stations in the Yeosu National Industrial Complex will determine the concentration of air pollutants measured every hour in 2019, analyze what factors affect them, and how they correlate with the air pollutant measurements. Six air pollutants (SO2, NO2, O3, CO, PM-10 and PM-2.5) measured at eight monitoring stations around Yeosu National Industrial Complex (Seogang-dong, Wolnae-dong, Munsu-dong, Yeocheon-dong, Deokchung-dong, Hwayang-myeon, Yulchon-myeon, Samil-dong) the measurement data for each hour of the year were downloaded to analyze the concentration by weather condition, time zone, season, separation distance from Yeosu Industrial Complex, and separation distance from Gwangyang Industrial Complex. SO2, NO2, and CO concentrations were significantly higher in winter, significantly lower in summer, and O3, PM-10, and PM-2.5 concentrations were significantly higher in spring. SO2, CO, PM-10, and PM-2.5 concentrations were significantly higher between 10 a.m. and 12 p.m., NO2 concentrations were significantly higher between 7 a.m. and 9 a.m., and O3 concentrations were significantly higher between 13 p.m. and 15 p.m.(p<0.001). The concentration of air pollutants (SO2, NO2, CO, PM-10, PM-2.5) excluding O3 was found to have a negative (-) correlation with weather condition, and in the case of O3, it was found to have a positive (+) correlation with PM-10, PM-2.5, temperature and wind speed. It was confirmed that the concentration of air pollutants emitted from the Yeosu National Industrial Complex differs depending on the season, time and distance to the industrial complex. This study aims to establish measures to minimize health damage to residents living relatively close to the industrial complex and contribute to the establishment of management and response measures according to the properties of substances to reduce the concentration of air pollutants in the future.

대구광역시 장애인의 삶의 만족도와 이에 영향을 미치는 요인

예민해,최병렬,감신,이희봉,심길택,이상수 한국건강관리협회 1998 건협 Report Vol.1 No.-

대구광역시 장애인의 건강관심도, 건강실천행위, 건강상태

예민해,최병렬,감신,이희봉,심길택,이상수 한국건강관리협회 1998 건협 Report Vol.1 No.-

대구광역시 장애인의 유병률 및 생활양식

예민해,최병렬,감신,이희봉,심길택,이상수 한국건강관리협회 1998 건협 Report Vol.1 No.-

제조업 종사 지체장애근로자의 스트레스 관련요인

정민예,박정일,구정완,노영만 大韓産業醫學會 2003 대한직업환경의학회지 Vol.15 No.1

목적: 본 연구는 지체장애근로자의 스트레스의 정도를 파악하고 이에 영향을 미칠 것으로 추정되는 여러 요인 들 즉 일반적 특성, 장애관련 특성, 직업관련 특성, 직무 스트레스 원, 중재변인들과의 관련성을 규명함으로써 지체장애근로자들의 스트레스의 예방적 관리 방안에 대한 방향을 설정하는데 필요한 자료를 구하고자 수행하였다. 방법: 본 연구의 대상자는 경·인 지방 제조업 종사 지체장애근로자로 방문과 우편 설문 조사를 통하여 응답한 341명이었다. 스트레스 수준의 측정은 신뢰도와 타당도가 인정된 Goldberg의 GHQ-60을 수정보완한 사회 심리적 건강 측정도구인 Psychosocial Well-being Index(PWI)를 사용하였다. 관련변수들은 일반적 특성, 장애관련특성, 직업관련특성과 직무 스트레스 원으로 하였고 기타변수로 조직 외 요인(가정요인, 사회적 자원), 개인관련요인(욕구 및 가치, A형 행동, 통제소재 및 인구통계 특성), 자아존중감, 대처전략으로 설정하였다. 수집된 자료는 SAS 6.12 통계프로그램으로 분석하였다. 결과: 지체장애근로자의 스트레스수준에 영향을 미치는 관련요인은 다변량 로지스틱 회귀분석을 이용하여 분석한 결과 본인이 지각한 건강상태가 좋지 않은 경우, 자아 존중감이 낮은 경우, 규칙적 운동을 하지 않은 경우, 업무 중 장애로 인한 어려움을 느끼는 경우, 집안이동능력이 독립적이지 못한 경우, 직업에서 집단 갈등이 있는 경우, 그리고 역할 갈등을 느끼는 경우, A형 행동 유형인 경우였다. 결론: 지체장애근로자의 스트레스 수준을 낮추기 위해서는 건강증진프로그램의 개발과 제공, 작업보조시설 지원과 더불어 집단갈등 및 역할갈등을 포함한 직업관련갈등을 감소시키기 위한 방안마련이 요구된다. Objectives: This study was performed to measure the stress level of physically disabled workers, and to inestigate the relationship between the stress dimensions and stress inducting factors of physically disabled workers in the Korean manufacturing industry. Methods: The sample used in this study consisted of 341 physically disabled workers who had been working at companies in Seoul, Inchon, and Gyung-gi provinces. The Psycho-social Well-being Index (PWI), a modified version of Goldberg's 60-items of General Health Questionnaire (GHS), was used to measure the stress level. The following independent and moderate variables were desinged for the same purpose. The independent variables were general and disability characteristics, workplace-related characteristics, and job stressor of the respondents. The other variables included organization-related stressors (social and family support) and person related stressors (needs and values, type A behavior pattern, locus of control and demographics), self-esteem and coping strategy. The collected data were analyzed using SAS version 6.12 program. Results: Multiple logistic regression analysis showed that the significant variables on the stress level of physically disabled workers were poor self-perceived health status, low self-esteem, absence of regular exercise, physically disabled condition affecting work performance capability, dependent mobility at home, interpersonal conflict, role conflict and A type behavior pattern. Conclusions: The results of this study suggest that appropriate health program should be established and provided for reducing the stress of physically disabled workers in the manufacturing industry. In addition, various vocational programs for decreasing interpersonal and role conflicts should be developed.