SM45C의 Laser 표면개질 조건에 따른 마멸특성에 관한 연구

옥철호,임동욱,서영백,박흥식,전태옥 동아대학교 생산기술연구소 2000 生産技術硏究所硏究論文集 Vol.5 No.1

Surface modification of plain carbon steel (SM45C) by Laser are usually much finer and stronger than the base metals. Nd-YAG laser source changes and refines the microstructure of the near surface layer, leading to enhanced hardness and wear resistance. The present study was undertaken to investigate the wear behavior and a processing parameters such as, power density, pulse width, defocusing distance, and molten depth for surface modification. The wear test was carried out under different experimental condition using the wear test device and the annular surfaces of wear test specimens as well as mating specimen of alumina ceramics(Al_2O_3) was rubbed in dry sliding condition. The results show that molten depth and width depend on defocusing distance. The wear loss was much in lower speed range below 0.2m/sec and in higher speed range above 0.7m/sec, but It was little in intermediate speed range. It depends on oxidation and wear speed.

여자 수영 및 유도선수의 골밀도에 관한 연구

옥영철,김영준 東亞大學校 附設 스포츠科學硏究所 1997 스포츠科學硏究論文集 Vol.15 No.-

It is has been suggested that physical activity may increase bone mineral density in female, thereby prevent development of osteoporosis later in life. The test subjects was 23 students of university women, consisted of non-athlete group(n=8), and swimmers(N=7), judo players(n=8). Measurements of bone mineral density were performed with SQCT(Spiral quantitative computed tomography) at the lumbar(L1-3),femur(femur neck ward's triangle, grate trochanter) parts. The results from this study are as follows. 1. There was significant difference between swimmers, judo players, and non-athletes in lumbar bone density. 2. There was significant difference between swimmers, judo players, and non-athletes in femur(ward's traingle and grate trochanter) parts bone mineral density.(p<0.05) 3. Bone mineral in Swimmers were lower than judo players.

무첨가 및 첨가제 윤활유에 따른 마멸입자 형태해석

서영백,옥철호,김동호,박흥식,전태옥 동아대학교 공과대학부설 생산기술연구소 1998 生産技術硏究所硏究論文集 Vol.3 No.2

This paper was undertaken to do morphological analysis of wear debris on no additive and additive lubricating oil. The lubricating wear test was performed under different experimental conditions using the wear test device was made in our laboratory and wear specimens of the pin on disk type was rubbed in paraffine series base oil by materials, varying applied load, sliding distance, oil additives such as stearine acid, DBDS, TCP. Morphologic character of wear debris is easily distinguished by four shape parameter(50% volumetric diameter, aspect, roundness and reflectivity). As the applied load sliding distance increase, size and shape of wear debris was complexed, but reflectivity was decreased, a large wear debris was apt to be oxidezed.

폐흡충증으로 확진된 고립성 폐결절 1예

유영권,김규식,김윤현,나국주,김경수,임성철,김영철,박경옥 全南大醫大 2001 전남의대학술지 Vol.37 No.2

평면연삭버어의 가공조건에 의한 영향

이광영,옥철호,서영백,박흥식,전태옥 동아대학교 공과대학부설 생산기술연구소 1998 生産技術硏究所硏究論文集 Vol.3 No.2

This study has been carried out to prevent and decrease the grinding burr under various working conditions; number of grinding passes, depth of cut, hardness of the materials and work speed. Grinding wheel is WA grinding wheel and workpieces are SM45C, SS41, SCM23 and STS 304. The results of tained from this study are as follows; The length of gringing burr increased with increasing grinding passes and it has nothing to do with materials and heat treatment. The size of grinding burr increased with increasing grinding depth and feed speed. The size of grinding burr decreased with increased cross setion and of workpiece. According as the hardness of material was increased, the width of grinding burr decreased conspicuously owing to suppression of plastic zone of burr root part.

전통 발효주로부터 glutathione 고함유 효모 Saccharomyces cerevisiae FF-8의 분리·동정 및 최적 생산조건

박진철,옥민,차재영,조영수 한국응용생명화학회 2003 Applied Biological Chemistry (Appl Biol Chem) Vol.46 No.4

본 연구에서는 glutathione(γ-L-glutamyl-cysteinlyl-glycine)을 다량으로 함유하는 효모 균주를 전통 발효주로부터 분리하여 glutathione 생산 조건을 검토하였다. 분리된 균주는 형태학적, 생리학적 및 생화학적 특성을 검토한 결과 Saccharomyces cerevisiae로 동정되어 FF-8로 명명하였다. Saccharomyces cerevisiae FF-8의 glutathione 생산 조선을 YM(glucose 1.0%, acid peptone 0.5%, yeast extract 0.3%, malt extract 0.3%) 배지를 기본으로 하여 최적 온도, 교반속도 및 초기 pH의 조건을 검토하였다. Glutathione 생산은 30℃, 교반속도 100rpm 및 pH 6.0에서 72시간 동안 진탕 배양하였을 때 가장 높았으며, 이때 glutathione 생산량은 72.0㎎/ℓ이였으며, 건조 균체량은 5.2g/ℓ이었다. In this study, strain of high-producing intracellular glutathione was isolated from Korean traditional rice wine. The isolated strain was identified as Sacharomyces cerevisiae based on the morphological, physiological and biochemical characteristics, and was designated as FF-8. The optimal condition for glutathione production by Sacharomyces cerevisiae FF-8 was obtained after cultivation with shaking for 72 hours in the YM medium. The optimal temperature, shaking rate and initial pH for the glutathione production were 30℃, 100 rpm and pH 6.0, respectively. The dry cell weight and glutathione concentration produced by Sacharomyces cerevisiae FF-8 were 5.2 g/ℓ and 72.0㎎/ℓ, respectively, under the optimal culture condition.

Bacillus sp. FF-7에 의한 항산화물질 생산조건과 항산화 활성

차재영,김효정,전방실,박진철,옥민,조영수 한국응용생명화학회 2003 Applied Biological Chemistry (Appl Biol Chem) Vol.46 No.3

발효식품 시료로부터 분리된 세균을 DPPH(α,α¹-diphenyl-β-picrylhydrazyl) 전자공여능으로 항산화 활성을 측정하여 가장 활성이 강한 균주를 선별하여 형태학적, 생화학적, 생리학적 특성 및 16S rRNA 염기서열을 조사한 결과 Bacillus sp.으로 판명되어 FF-7로 명명하였다. DPPH 전자공여능법에 의한 Bacillus sp. FF-7이 생산하는 항산화물질의 최적 생산 배지조건은 탄소원 2% galactose와 질소원 1% tryptone 첨가였다. Bacillus sp. FF-7에 의해 생성된 항산화 물질의 활성을 DPPH 전자공여능, 흰쥐 각 조직 microsomal 실험계 및 linoleic acid 과 산화지질 실험계에서 malondialdehyde를 thiobarbituric acid(TBA)방법으로 측정하였다. 흰쥐 각 조직 microsomal 실험계에서 지질과산화에 대한 항산화 효과는 뇌(97.50%)>심장(79.95%)>신장(77.84%)>비장(77.47%)>고환(69.96%)>간장(62.45%) 순이였다. Linoleic acid의 과산화지질률 TBA법으로 측정한 결과 반응 4일째까지 억제 효과가 강하게 나타났으며, 동시에 대조구로 사용한 0.05% BHT 첨가구에서도 실험종료시까지 항산화 활성이 강하게 나타났다. The antioxidative activity of antioxidative substances produced from several bacterial strains isolated from fermented foods were tested by DPPH (α,α'-diphenyl-β-picrylhydrazyl) free radical scavenging activity. One of the strains showing the highest antioxidative activity was identified as Bacillus sp. based on the morphological, biochemical, physiological characteristics, and 165 rRNA sequence, and named FF-7. The molt optimal medium condition for the production of antioxidative substance from Bacillus sp. FF-7 was 2% galactose as carbon source and 1% tryptone as nitrogen source. The antioxidative substance produced from FF-7 in these cultural medium was also tested by in vitro experimental models, the peroxidation of linoleic acid and the peroxidation of rat tissues microsomes by using thiobarbituric acid (TBA) for assay of free rnalondialdehyde production. The antioxidative avtivity against lipid peroxidation of rat tissues microsomes was shown in the following order; brain 97.50% > heart 79.95% > kidney 77.84% > spleen 77.47% > testis 69.96% > liver 62.45%. The antioxidative substance produced from FF-7 on linoleic acid peroxidation by TBA method was effectively inhibited during four days, and 0.05% BHT(butylated hydroxytoluene) used comparative control was also effectively inhibited. Results showed that the highest antioxidative activity by DPPH method of antioxidative substance produced from Bacillus sp. FF-7 was obtained by supplementing 2% galactose as carbon source and 1% tryptone as nitrogen source in cultured medium, this substance effectively inhibited the formation of TBARS in brain microsome in vitro system and in linoleic acid peroxidation.

기관지 방선균증의 임상 1례

이은영,장태원,정만홍,옥철호,이규원,손창배,이지숙,신은경,서정아,백종현,김영옥 고신대학교의과대학 2007 고신대학교 의과대학 학술지 Vol.22 No.2

Actinomycosis is a chronic suppurative infection, whitch infiltrates mucosa-associated tissues. Thoracic, pelvic and cervicofacial infections of actinomyces are not uncommon, but endobronchial actinomycosis is rarely reported. We report a case of a 29 year old man who presented with a recurrent pneumonia and chronic cough. Fiberoptic bronchoscopy revealed occlusion of the right. lower medio-basal segment bronchus with exophytic endobronchial mass. The diagnosis was confirmed histologically by demonstration of sulfur granules in the bronchoscopic biopsy of the mass. Intravenous administration of amoxacillin and clindamycin followed by oral amoxacillin and clindamycin therapy resulted in complete recovery.

On-line 판매 및 배송용 분화류를 위한 지류 포장 상자의 표준화 연구

문선옥,김철환,김선영 경상대학교 농업생명과학연구원 2003 농업생명과학연구 Vol.37 No.1

본 연구에서는 최근 급증하고 있는 on-line 판매 및 배송용 분화류를 위한 지류 포장상자의 개발 및 표준화를 시도하였다. 관상용인 란(호접란, 풍란, 심비디움 등), 허브, 선인장 등과 같은 분화류는 해마다 급속도로 판매가 증가하고 있는 실정이지만, 이들의 운송 혹은 배송을 위한 전용 포장 상자가 부재하였다. 따라서 on-line 판매 및 배송용 분화류를 위한 전용 지류 포장 상자를 설계 및 제작하여 포장된 분화류의 고급 브랜드화, 운송 중의 안전성, 운반의 편리성을 도모하였다. 또한 개발된 포장 상자의 허용 하중, 내부 지지대의 적정 설계, 분화류의 다양한 크기에 맞는 포장 상자의 치수 등을 고려하여 표준화 시안을 마련하였다. This paper was a study on standardization and development of paper boxes for packaging flowerpots for on-line sale and delivery. The boxes for packaging flowerpots have hardly been developed so that a standardization for the boxes was required for better packaging than before. Specifically, sales of orchids, herbs, cactus and so on have rapidly growing up every year. As a result, the development of a new design in addition to the standardization of the paper boxes for packaging flowerpots in various sizes were made based on consideration including high class design, safety and convenience during transfer or delivery, the maximum load of flowerpots, design of interior pedestal, and various dimensions for different sizes of flowerpots.

백서의 카드뮴 중독시 마늘, D-penicillamine 및 N-acetyl-DL-penicillamine의 방어효과에 관한 연구

李榮玉,車喆煥,林國煥 고려대학교 의과대학 1986 고려대 의대 잡지 Vol.23 No.3

In recent studies, they have insisted that the Korean garlic which contains a large amount of disulfide and sulfhydryl compounds and selenium, has a remarkable protective effect against heavy metal poisoning. The mechanism of the effect, however, has still not been proved in detail. Authors tried to compare the protective effect of the garlic on cadmium poisoning with those of N-acetyl-DL-penicillamine (APEK) and D-penicillamine (PEN). For the purpose, the experiment was performed in two steps of treatment. In first step, Experiment Ⅰ, CdCl₂ (1 mg/Kg of body weight) was injected into the peritoneal cavity of rats with experimental agents such as garlic, APEX or PEN for 7 days, and after that only the experimental agents were administered per os to each group of rats for 23 days respectively. In second step, Experiment Ⅱ, CdCl₂ alone was injected into the peritoneum for 7 days and 24 hours after that the experimental agents were administered for 23 days in the same way. The dosage of experimental agents was doubled in last 1 week of 23 days in the second step. For the treatment with the experimental agents, garlic was fed with 6.4% mixture pellets, and APEN (60 mg/Kg/day) and PEN (40 mg/Kg/day) were dosed with water. After the treatment, cadmium levels in liver, kidney, testis and bone were measured and the histopathological examination of testis was done. The results of the study were as follows; 1. When the experimental agents were administered from the beginning of cadmium injection (Experiment I), cadmimum levels in each organs of garlic or APEN-dosed group were markedly lower than those of cadmium-alone-dosed group and also of PEN-dosed group. In kidney, cadmium level of PEN-dosed group was higher than that of cadmium-alone-dosed control group. The extent of damage due to cadmium in the histopathological examination of testis, was mild in garlic or APEN-dosed group compared with the FEN-dosed group. The degree of damage in the latter group was similar with that of cadmium-alone-dosed group. 2. When the experimental agents were administered 7 days latter the cadmium alone was injected (Experiment Ⅱ), the cadmium levels in each organ were decreased little and the histopathological damage in testis was not recovered by the administration of experimental agents. We can conclude, therefore, that the protective or preventive effect of garlic in terms of its potency would be similar with that of APEX and superior to that of PEN. However, it was also revealed that the above mentioned experimental agents including garlic was not so effective as we expected for the treatment of cadmium poisoning if we administer them after the intoxication happened.