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.

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.

연령에 따른 한국인의 음향지표 변화와 특성

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

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.

류마토이드 關節炎의 韓·洋方的 藥物治療의 最新傾向 考察

吳永仙,吳旼錫,宋泰元 대전대학교 한의학연구소 2002 한의학연구소 논문집 Vol.11 No.1

NSAIDs(Non-steroidal anti-inflammatory drug), Steroid(corticosteroid), DMARD(Dise modifying anti-rheumatic drug), Immunosuppressive agent, BRM(Biologic response modifer) western medication of Rheumatoid arthritis. Recent trends in western medication of Rheum arthritis is an inverted pyramid treatment. Byunjeungsichi(辯證施治), Yakchim(藥針), Oechibub(外治法 external treatment) are orie medication of Rheumatoid arthritis. Yakchim(藥針) and Oechibub(外治法 external treatment) the advantage of trouble in oral administration.

급성 연쇄상구균 감염후 사구체 신염에 동반된 고혈압 뇌증 1례

하태선,차상훈,이경은,엄정민 충북대학교 의과대학 충북대학교 의학연구소 1999 忠北醫大學術誌 Vol.9 No.2

고혈압성 뇌병증은 고혈압 환자에서 고혈압과 관련된 두통, 경련, 시각장애 및 다른 신경학적 장애를 동반하는 증후군이다. 증례는 13세 여자환아로 급성 연쇄상구균 감염후 사구체 신염에 동반된 고혈압성 뇌병증 환자였다. 내원시 혈압은 150/110 mmHg 였고 내원당시 검사소견상 단백뇨, 혈뇨, C3의 감소 소견을 보였다. 내원 2일째 자기공명영상을 시행하였고 스핀에코 T2 강조영상에서 양 후두엽과 후 측두엽에 고신호의 이상 부위들이 발견되었다. 치료후 실시한 자기공명영상은 정상 소견을 보였다. 본 저자들은 급성 사구체 신염 환자에서 자기공명영상으로 고혈압성 뇌병증을 진단하고 치료한 1례를 문헌고찰과 함께 보고하는 바이다. Hypertensive encephalopathy is a syndrome consisting of headache, seizures, visual changes, and other neurologic disturbances in patients with elevated systemic blood pressure. We experienced a 13-year-old girl who presented with the manifestations of hypertensive encephalopathy in acute post-streptococcal glomerulonephritis. She visited our hospital because of generalized tonic-clonic seizure after severe headache. On admission her blood pressure was 150/110 mmHg and initial laboratory findings revealed proteinuria, hematuria and decreased C3 level and, T2-weighted MR image showed increased T2 signal in both occipital lobes, suggesting cerebral edema. On follow-up MRI, pathologic lesions were improved. We described a case of hypertensive encephalopathy in acute post-streptococcal glomerulonephritis diagnosed by MRI with a brief review of some related literatures.

관상 동맥 질환에서 아포 E 지단백 유전자 다형성과 혈청 지질치와의 관계

곽선영,김성구,정호석,이유경,이광희,김철현,최태명,현민수,권영주 순천향의학연구소;Soonchunhyang Medical Research Institute 2000 Journal of Soonchunhyang Medical Science Vol.6 No.1

Background and aims: The Apolipoprotein E is a ligand of both the protein component LDL receptor as well as the apo E LDL-Receptor related protein (LRP). It modulates the receptor binding of lipoproteins, with the apolipoprotein E found on cell surfaces as its component, thus serving an important role in the lipid metabolism by carrying out the intracellular transport of cholesterol in lipoproteins. The gene for apolipoprotein E is the product of three common genotypes as well as many more rare alleles. The common genotypes are ε2, ε3, and ε4, and are expressed in the three phenotype isoforms of E2, E3, and E4. In the event that E4 is the main component, a rise in the cholesterol level, as the result of down-regulation of the LDL receptor, is observed. Therefore, those samples with E4 genotypes are known to be in much higher risk of coronary artery disease than those with ε3/ε3, while those with ε2 are in low risk (with the exception of hypertiglyceremai Ⅲ). The aim of this study is to analyze in patients with ischemic heart disease the role of aplipoprotein E alleles in order to seek its correlation with coronary artery disease, as well as to seek whether the polymorphism of apo E produces any differences in the severity of coronary artery disease according to plasma lipid levels. Methods: The subjects for study were 273 patients admitted to the Internal Cardiology Division of the Soonchunhyang University Hospital form December 1998 to February 1999. The subjects were divided into the two groups of which one was ischemic heart disease (IHD) experiment group totaling 105 (avg.60.1 years of age, male/female ratio = 69/36) and the control group totaling 168 (avg. 59.7 years of age, male/female = 73:95). The coronary angiogram was given to 127 subjects, and of this total, 94 have developed significant stenosis in the coronary artery. The stages of the analyzing of the apo E phenotype was first, the separation of DNA from the blood samples, subjecting it to the PCR from with 228 base pairs of expanded products were obtained. The band was determined by means of the reverse hybridization principle on the nitrocellulose strip. Results: From the 105 patients the distributions of apo E phenotypes were as follows: ε3/2(5.7%), ε4/2(1.9%), ε3/3(70%), ε4/3(20%), ε4/4(1.9%). The relative frequencies of each allele are as follow: ε2 (0.038), ε3 (0.833), ε4 (0.128). The results show as follows: ⅰ) The IHD experiment group to have a higher occurrence of ε4/3 phenotypes as well as ε4 alleles than the control group. ⅱ) Both the control group and IHD group showed the largest distribution of ε3/3 for phenotypes, and ε4 for alleles. ⅲ) The IHD group showed less ε2/3 phenotypes as well as significantly less allele frequency of ε3 in comparison to the control group. ⅳ) the IHD group showed a much lower level of HDL in comparison to the control group, while the LDL was significantly higher; samples including the apo ε2 showed a significantly higher level of HDL than those without. Among the control group, samples including apo ε2 showed a significantly higher level of TG (triglyceride) than samples without. No significant difference was found between the experiment apo ε4 sample and the control plasma lipid sample. ⅴ) No significant correlation was found between an apo E polynorphism and the number of involved arteries of a coronary angiogram. Conclusion: Between the experiment IHD group and control group were found differences in the frequency of alleles. The polymorphism of apo E alleles may contribute as a risk factor to the development of heart disease by involving itself in the metabolism and modulation of plasma lipids.