Effect of Forging Type on the Deformation Heterogeneities in Multi‑Axial Diagonal Forged AA1100

Min‑Seong Kim,Sang‑Chul Kwon,Sun‑Tae Kim,Seong Lee,Hyo‑Tae Jeong,Shi‑Hoon Choi 대한금속·재료학회 2019 METALS AND MATERIALS International Vol.25 No.3

The present study investigated the effects that different types of forging exert on the deformation heterogeneities developedin AA1100 during multi-axial diagonal forging. To measure the deformation heterogeneities of deformed workpieces, thevalues for hardness and Kernel average misorientation were measured at the center section following each forging process. Type-D forging that consists of diagonal forging and return-diagonal forging was relatively advantageous compared withType-P forging that includes plane forging and return-plane forging for minimizing the non-uniformity of deformationdeveloped in workpieces. The effective strain developed in a workpiece during the 2 types of forging was simulated using3-D FEA. FEA revealed that the positions and degrees of occurrence for soft and hard-zones in workpieces vary greatlydepending on the forging type. Type-D forging was relatively advantageous compared with Type-P forging for minimizingthe non-uniformity of effective strain developed in workpieces.

생식용 굴(Crassostrea gigas) 작업장의 위생안전성에 대한 모니터링

강경태 ( Kyung Tae Kang ),박선영 ( Sun Young Park ),최종덕 ( Jong-duck Choi ),김민주 ( Min Joo Kim ),허민수 ( Min Soo Heu ),김진수 ( Jin-soo Kim ) 한국수산과학회 2017 한국수산과학회지 Vol.50 No.2

This study assessed the safety of raw oysters (Crassostrea gigas) for consumption during processing in a processing plant. Bacterial contamination (e.g., viable cell counts, coliform groups, and pathogenic bacteria) and chemical contamination (e.g., heavy metals and shellfish toxins) were measured on raw oysters, a processing equipment, employees, and work areas. No total mercury, lead, paralytic shellfish poison, diarrheic shellfish poison, or norovirus was detected in any post-harvested oyster samples. However, the cadmium level ranged from 0.1-0.2 mg/kg. The viable cell count and Escherichia coli and coliform group levels in post-harvested oysters ranged from 4.00-4.54 log CFU/g, ND-210 MPN/100 g, and 110-410 MPN/100 g, respectively. The viable contaminating cell counts on employees, equipment, and work areas were in the range of 0.90-3.46 log CFU/100 cm². Airborne bacteria in the work areas ranged from 0.60 to 1.81 log CFU/plate/15 min. Thus, no significant health risks were detected in the processing plant.

단신 : 실리콘의 염소화반응에 의한 사염화규소 제조

박균영 ( Kyun Young Park ),이미선 ( Mi Sun Lee ),김민철 ( Min Cheol Kim ),이찬희 ( Chan Hee Lee ),박회경 ( Hoey Kyung Park ),강태원 ( Tae Won Kang ),정해성 ( Hae Seong Jeong ),한경아 ( Kyoung Ah Han ),허원회 ( Weon Hoe Huh ),유지 한국화학공학회 2013 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.51 No.3

직경 25 mm의 파이렉스 튜브 내에서 실리콘의 유동층 염소화 반응이 수행되었다. 반응기에 공급되는 질소 유량0.8~1.0 L/min, 염소 유량 0.2 L/min, 반응온도 450℃, SiCl4 응축기의 냉매온도는 -5℃로 설정하였다. 반응기에 도입되는 가스 내 염소의 몰분율이 증가하면 SiCl4의 수율이 증가하였다. 반응가스 중 염소의 몰분율 0.2의 조건에서 SiCl4의 수율은 28% 이었다. 염소의 몰분율 증가는 반응열 상승에 의해 반응온도 상승을 가져옴으로써 안전을 고려하여 염소의 몰분율을 0.2 이상으로 올리지 못했다. 실리콘의 유동층 염소화 반응에 의한 사염화실리콘의 제조 가능성이 입증되 었으며, 향후 보다 가혹한 조건에서의 실용화 연구를 위한 기초로 활용될 수 있을 것으로 기대된다. The chlorination of a metallurgical-grade silicon was carried out in a fluidized bed reactor, 25 mm in diameter. The flow rate of the chlorine admitted into the reactor was 0.2 L/min and that of the carrier nitrogen was 0.8~1.0 L/ min. The reactor temperature was maintained at 450℃ and the temperature of the coolant at the SiCl4 condenser was at -5℃. The SiCl4 yield increased with increasing the mole fraction of chlorine in the feed gas, exhibiting 28% at the mole fraction of 0.2. Further increase of the chlorine mole fraction was not attempted in a worry that the reactor might be failed due to the high exothermicity of the reaction. The production of SiCl4 from silicon by fluidized bed chlorination was demonstrated on a laboratory scale, which is a stepping stone for future studies under more severe conditions toward industrial application.

이동형 스크러버를 이용한 암모니아 및 톨루엔의 제거 효율

김재영 ( Jae-young Kim ),김장윤 ( Jang-yoon Kim ),이연희 ( Yeon Hee Lee ),김민선 ( Min Sun Kim ),김민수 ( Min-su Kim ),김현지 ( Hyun Ji Kim ),류태인 ( Tae In Ryu ),정재형 ( Jae Hyeong Jeong ),황승율 ( Seung-ryul Hwang ),김균 ( Ky 한국환경농학회 2018 한국환경농학회지 Vol.37 No.1

본 연구는 국내에서 다량 취급되고 있는 암모니아 및 톨루엔을 흄 상태로 노출시킨 후 흡수/흡착방법을 달리한 이동형 스크러버를 이용해 각 유해화학물질의 제거효율을 비교 분석하였다. 이동형 스크러버는 기 개발된 장치를 개선하여 와류세정에 의한 흡수, 유입풍속 조절의 장점을 살리고, 활성탄 및 카본필터를 통한 기체상 유해화학물질의 흡착방법 도입을 통해 단점을 보완하였다. 개선된 장치는 기초성능평가를 통해 적정 제어풍속이 검증되었고, 5% 암모니아수 용액을 흄 상태로 노출시켜 후드 흡입부, 송풍기 배출부 및 세정기가 정상 작동함을 확인하였다. 흡수/흡착방법에 따른 암모니아 제거효율은 90분 경과 후 C≥PCA>SWA 순으로 가장 우수한 SWA 군의 노출 농도별 제거 효율은 시간이 경과할수록 노출 농도와 무관하게 배출 농도는 증가되었고, 세정액의 pH는 산성에서 염기성으로 변화되었다. 또한, 시간 경과에 따른 노출 농도 별 세정액의 pH 변화와 배출구 농도 변화 사이에 0.9429~0.9491 수준의 정의 상관관계를 나타내었다. 흡착방법에 따른 톨루엔의 제거 효율은 초기 10분 경과 후 배출구농도에서 C>CMA≥GCA 순을 나타내다 90분 경과까지 일정한 농도로 유지되었다. 가장 우수한 GCA 군의 노출 농도 별 제거 효율은 초기 10분 경과 시 노출 농도에 비례하여 배출 농도가 높은 경향이었다. 이와 같은 결과를 통해 개선된 이동형 스크러버는 중화반응에 의해 산성 또는 염기성 유해화학물질의 제거뿐 아니라, 활성탄 등의 흡착기능 개선을 통해 VOCs 제거에도 효과적이었다. 하지만, 실제 현장에서 활용이 가능하도록 세정액 pH를 지속적으로 유지하여 연속적으로 흡수 제거할 수 있는 방법과 노출되는 화학물질 농도와 흡착제의 관계에서 파괴점, 포화점, 흡착속도 등의 물리적인 요소가 추가적인 연구를 통해 도출되어야 할 것이다. BACKGROUND: The mobile vortex wet scrubber was developed to remove the harmful chemicals from accidental releases. However, there was a disadvantage that it was limitedly used for volatile organic compounds (VOCs) such as toluene according to the physicochemical properties. This study compared the removal efficiencies of an improved mobile scrubber on toluene and ammonia by applying diverse adsorption and absorption methods. METHODS AND RESULTS: The removal efficiencies on harmful chemicals were examined using various adsorption and absorption methods of water vortex process (C), phosphoric acid-impregnated activated carbon adsorption (PCA), pH-controlled water (pH 2.5) vortex process absorption with sulfuric acid (SWA) after ammonia exposure, granular activated carbon adsorption (GCA), and activated carbon mat adsorption (CMA) after toluene exposure. As a result, the best removal efficiency was shown in the SWA for ammonia and GCA for toluene. Also, the SWA and GCA methods were compared with different concentration levels. In the case of ammonia exposure (5, 10 and 25%), there was no difference by concentration levels, and the concentration in the outlet gradually increased, with pH change from acid to base. In the case of toluene exposure (50, 75 and 100%), the outlet concentration was higher relative to the exposure concentration in the initial 10 min, but the outlet concentration was remained steady after 10 min. CONCLUSION: The newly improved mobile scrubber was also effective in removing VOCs through adsorption techniques (activated carbon, activated carbon fiber, carbon mat filter etc.), as well as removing acid-base harmful chemicals by neutralization reaction.

연령에 따른 한국인의 음향지표 변화와 특성

김형태,조승호,윤성문,선동일,김민식 대한이비인후과학회 2000 대한이비인후과학회지 두경부외과학 Vol.43 No.1

Am-Be 선원을 통한 중성자의 전단면적 측정

민영기,오선영,노태익,박상태,이대원,이삼열 東亞大學校 1996 東亞論叢 Vol.33 No.-

Total cross sections was measured for 6.45MeV∼8.96MeV (average 7.7MeV) neutron on ??, ??, ?? absorber using ?? fast neutron source. The 2" ø×2" NE-213 organic liquid scitillation detector was used as a spectrometer of neutrons and gamma-rays. The zero crossing time analysis method was introduced in order to obtain the pulse heigh spectrum of neutrons and n-γ pulse-shape spectrum was investigated. The ratio of neutron peak for a Vally was 1:20. The total cross section resulting from the experiment enabled us to suppose a optical model as a neutron model, obtain the radius of a nuclei.

마이크로 엔드밀에 의한 미세격벽가공의 가공특성에 관한 연구

민승기,이선우,이동주,이응숙,제태진 한국공작기계학회 2002 한국생산제조학회지 Vol.11 No.3

Recently, miniaturization and mass production are the main trends in manufacturing fields. Therefore, ultraprecision machining and MEMS technology have been taken more and more important position in machining of microparts. Micro endmilling is one of the prominent technology that has wide spectrum of application field ranging from macro parts to micro products, such as PDP ad IT components, in precision products manufacturing. However, decreasing of burr is significant problem in making smooth and precise parts in micro endmilling. This paper shows removal characteristics of burr generated by micro emdmilling process. This results satisfies micro for micro barrier ribs of heights is 50㎛, 100㎛, 200㎛, 300㎛, and observation from of burr. Additionally, it is necessary to understand the formation mechanism of burr of micro barrier ribs to find proper decreasing method.

정신분열병에 대한 리스페리돈의 효과 및 안정성

이민수,김용구,김영훈,연병길,오병훈,윤도준,윤진상,이철,정희연,강병조,김광수,김동언,김명정,김상훈,김희철,나철,노승호,민경준,박기창,박두병,백기청,백인호,손봉기,손진욱,양병환,양창국,우행원,이정호,이종범,이홍식,임기영,전태연,정영조,정영철,정인과,정인원,지익성,채정호,한상익,한선호,한진희,서광윤 大韓神經精神醫學會 1998 신경정신의학 Vol.37 No.1

연구목적 : 본 시험의 목적은 임상시험 시작전에 연구자들을 대상으로 PANSS Workshop을 통하여 PANSS, ESRS에 대한 국내에서의 표준화 작업을 구축하고 새로운 정신병 치료제인 리스페리돈의 효과와 안정성을 재확인하여 리스페리돈 사용에 대한 적정화를 이루는데 있다. 연구방법 : 1996년 4월부터 1996년 9월까지 국내 39개 대학병원 정신과에 입원중인 혹은 증상이 악화되어 입원하는 정신분열병 환자 377명을 대상으로 다시설 개방 연구를 시행하였다. 1주일간의 약물 배설기간을 가진후, 리스페리돈을 8주간 투여하였고, 기준점, 1주, 2주, 4주, 그리고 8주후에 평가되었다. 용량은 제1일에는 리스페리돈 1mg씩 1일 2회, 제2일에는 2mg씩 1일 2회, 제3∼7일에는 3mg씩 1일 2회 투여하였다. 이후 환자의 임상상태에 따라 임의로 증량할 수 있으며, 최대 일일 16mg을 초과하지 않도록 하였다. 추체외로 증상을 조절하기 위한 투약을 허용하였다. 임상증상 및 부작용의 평가는 PANSS(Positive and Negative Syndrome Scale), CGI(Clinical Global Impression) 그리고 ESRS(Extrapyramidal Symptom Rating Scale)을 사용하였다. 연구결과 : 377명중 343명(91%)이 8주간의 연구를 완결하였다. 치료 종결시점인 8주후 PANSS 총점수가 20% 이상 호전된 경우를 약물 반응군으로 정의할때, 약물반응군은 81.3%였다. 리스페리돈에 반응하는 예측인자로는 발병연령, 이전의 입원 횟수, 유병기간이 관련 있었다. 리스페리돈은 1주후부터 PANSS양성, 음성, 및 일반정신병리 점수상에 유의한 호전을 보여 효과가 빨랐다. CGI의 경우도 기준점에 비해 1주후부터 유의한 감소를 나타내었다. ESRS의 경우, 파킨슨 평가점수는 기준점과 비교해 투여 1주, 2주, 4주후 유의하게 증가되었다가 8주후 기준점과 차이가 없었다. Dystonia 평가점수는 1주후만 유의한 증가를 보였으며, dyskinesia 평가점수는 유의한 차이가 없었다. 혈압, 맥박수의 생명징후 및 일반 혈액학 검사, 생화학적 검사, 심전도 검사에서 유의한 변화는 없었다. 결 론 : 이상의 다시설 개방 임상 연구를 통해 리스페리돈은 정신분열병 환자에서 양성증상뿐만 아니라 음성증상 및 전반적인 증상에도 효과적인 것으로 사료된다. 보다 명확한 평가를 위해서는 다른 항정신병약물과의 이중맹검 연구가 필요할 것으로 생각되며, 또한 장기적 치료에 대한 평가도 함께 이루어져야 하겠다. Objective : The purpose of this study was to investigate the efficacy and safety of risperidone in the treatment of Korean schizophrenic patients. Method : This multicenter open study included 377 schizophrenic patients drawn from 39 university hospitals. After a wash-out period of 1 week, the schizophrenic patients were treated with risperidone for 8 weeks and evaluated at 5 points ; at baseline, and 1, 2, 4 and 8 weeks of treatment. The dose was increased from 2mg/day(1mg twice daily) to 6mg/day(3mg twice daily) during the first week and adjusted to a maximum of 16mg/day over the next 7 weeks according to the patient's clinical response. Medication to control extrapyramidal symptoms was permitted. The psychiatric and neurological status of the patients was assessed by PANSS, CGI, and ESRS scales. Results : 343(91%) of 377 patients completed the 8-week trial period. Clinical improvement, as defined by a 20% or more reduction in total PANSS score at end point, was shown by 81.3% of patients. The predictors of response to risperidone were associated older age, shorter duration of illness, fewer previous hospitalization. Risperidone had rapid onset of action ; a significant decrease of the total PANSS and three PANSS factor(positive, negative, general), and CGI was already noticed at the end of first week. For the ESRS, parkinsonism rating scores were significantly increased until week 4 comparing with baseline. Dystonia rating scores were significantly increased until week 1, and dyskinesia rating scores were not significantly changed during the study. Laboratory parameters including vital sign, EKG, hematological, and biochemical values showed no significant changes during the trial. Conclusions : This study suggests that risperidone is generally safe and effective against both the positive and negative symptoms in our group of patients.

제주대학교와 창원대학교의 지체장애인 편의시설 비교분석

고상선,박철민,김태일 제주대학교 공과대학 첨단기술연구소 2002 尖端技術硏究所論文集 Vol.13 No.2

Colleges and Universities are one of our whole life educational facilities for the disabled regarding job training opportunities are academic goal achievement. However it is usual for the disabled students to be deprived of their opportunities to study and to prepare their future life on campus because of physical obstacles of campus environment. Therefore this study provides what are the physical obstacles on campus, how to use the college's facilities for the disabled to achieve their academic goals and to have job training opportunities just like ordinary students, and how to improve the campus environment which is based on the concept of Universal Design.

방사선조사 후 유표피암종세포내 칼슘농도의 변화와 apoptosis 발현에 관한 연구

이삼선,문제운,허민석,박태원,유동수,최순철 大韓口腔顎顔面 放射線學會 1999 Imaging Science in Dentistry Vol.29 No.1

Purpose: Ionizing radiations have been reported as an apoptosis initiating stimulus in various cells and it has established that sustained elevations in [Ca²+] can lead to DNA fragmentation by Ca²+-dependent endonucleases, ultimately resulting in apoptotic cell death. The previous experiments have been reported by using primarily thymocytes and lymphocytes and the change of [Ca²+] was measured only by minutes or hours respectively. We need to evaluate [Ca²+] in both several minutes and hours after irradiation of radiation of radiation therapy and verify the apoptotic cells. Materials and Methods: We have measured [Ca²+] in human gingival epitheloid cancer cell with 10 Gy irradiation, at minutely intervals and hourly intervals using digitized video-intensified fluorescence microscopy and the fluorescent Ca²+ indicator dye, fura-2. In order to find out that the transient rise in [Ca²+] could induced apoptosis, cells were incubated for 1 hour at 37℃ with TdT enzyme, rinsed and resuspended containing fluorescence and observed under a confocal fluorescence microscope. MTT assay was done to determine cell activity and LDH assay was done to determine the amount of necrotic cells. Results: After irradiation, the transient and temporal increasing of [Ca²+] in the KB cells was founded. Though, there was no change in the intracellular [Ca²+] at 30 minutes and 2 hours after irradiation. We could detect of DNA fragmented cells at 4 hours after 10 Gy irradiated cells. There were no significant differences between 4 hour, 1 day, 3 day cells. There were no significant differences in MTT and LDH assay between the irradiated group and the control group after 4 hours and 1 day. Though after 3 days there were differences in MTT and LDH assay between the irradiated group was significantly decreased than the control group, in LDH assay the number of necrotic cell death of the irradiated was higher than the control group. Conclusion: In KB cells there were incipient and temporal increasing of the [Ca²+] with 10 Gy irradiation and the apoptosis was founded from 4 hours later which was earlier than seeing of the change of the amount of the cellular ability and necrosis.(J Korean Oral Maxillofac Radiol 1999:29:109-117)