Glycol Oleates의 합성과 절삭유제로서의 물성

최형기,이호식,이치우,강신춘,노시태 한양대학교 공학기술연구소 1993 공학기술논문집 Vol.2 No.1

Glycololeates for the application of cutting fluid were synthesized from oleic acid and glycols such as ethylene glycol, diethylene glycol and triethylene glycol. The ratio of glycol-monooleate and dioleate in product according to the reaction condition was analyzed by TLC, CC and HPLC. Properties of glycololeates as cutting fluid were examined by various testing methods such as profile test, pH test, anti-foaming test friction coefficient test and emulsion stability test to compare those of base oil and cutting fluid trading in the market. Non-catalytic reaction of glycololeates synthesis was showed too low conversion rate, but too fast conversion rate and deep color deterioration of products was obtained with acid-catalyses reaction. Using the SnCl2 catalyst, conversion rate was medium range and products which suitable for the application of cutting fluid with mild colored and with desirable mono- and di-oleate composition was obtained. Cutting fluidal properties of glycololeates with SnCl2 catalyst were better than those of base oil, and were similar level to those of cutting fluid containing various additives.

항 Vancomycin 내성균성 항생물질을 생산하는 Streptomyces sp.AMLK-335의 배양조건

이기형,임대석,최경희,이경호,김창한,김정환 건국대학교 동물자원연구센터 2000 動物資源硏究誌 Vol.21 No.-

본 연구는 새로운 항 vancomycin 내성균성 항생물질을 개발하기 위하여 실시되었으며, 전국 각지의 토양 시료로부터 분리한 방선균 중 vancomycin 내성균주인 K-98 Enterococcus faecium 642, K-98 Enterococcus faecium 637 균주에 대하여 항생물질을 생산하는 분리균주 AMLK-335를 선정하여 이 균주의 항생물질 생산에 대한 최적 발효 조건을 검토한 결과, 탄소원 첨가로는 glycerol(0.5%), 질소원 첨가로는 yeast extract(0.5%)가 가장 효과적으로 항생물질 생산에 이용되었고, 비타민을 첨가에 따른 항생물질 생산성의 차이는 크게 나타나지 않았으나, calcium pantothenate 첨가시 항균활성이 비교적 높아졌으며, 금속이온의 첨가는 K+, Pb+, Ba²+, NA²+ , Ca²+를 첨가하였을 때는 항생물질의 생산성이 비교적 높아졌으며, 그중 Ca²+ 첨가구가 가장 생산성이 높았으며, Fe²+ , Hg+의 금속이온을 첨가하였을 때는 항생물질 생산성이 감소하였으며, CaCO₃첨가는 비첨가구보다 높은 항생물질 생산성을 보였으나, 첨가량에 따른 영향은 대체적으로 없었다. pH의 변화에 따른 생산성은 전반적으로 pH가 항생 물질 생산에 영향을 미치지 못하였으나, pH 4.5∼6.0 부근에서는 비교적 높은 항생물질 생산성을보였으며, 통기량에 따른 항생물질 생산성은 통기량이 많을수록 항생물질 생산이 좋았다. 한편 배양기간에 따라 항생물질 생산성을 조사한 결과, 5일째에 가장 높은 항생물질 생산성을 나타내었으며, pH의 변화는 배양 초기에 하강하였다가 점차 상승하는 경향을 보였다. This study was carried out for examining antibiotic productivity of the strain Streptomyces sp. AMLK-335 producing anti-VRE antibiotic. According to different condition, the strain was cultured for 4 days at 27℃ and determined cell growth, pH value and antibiotic productivity using disk diffusion method. In the experiment, the strain Streptomyces sp. AMLK-335 was examined various culture conditions which was added 8 carbon sources, 12 nitrogen sources, 8 vitamins and 11 metal ions in each time and controlled concentration of CaCO₃, initial pH and aeration. From the studies of conditions for antibiotic production, antibiotic productivity was the best to use 0.5% glycerol as carbon source and 0.5% yeast extract as nitrogen source. When several vitamins were added to medium, there was little difference in antibiotic productivity. But the addition of calcium pantothenate slightly increased antimicrobial activity. The addition of metal ion, such as K+, Pb+, Ba²+, NA²+ and Ca²+ slightly increased antibiotic productivity except Fe²+ and Hg+. The addition of CaCo₃showed higher than non-addition experiment in antibiotic production, but there wasn't generally influenced at addition concentration. According to pH change, antibiotic productivity was increased at pH 4.5∼6.0, and when there was a lot of aeration, antibiotic productivity was increased.

외상성 고막천공의 임상적 고찰

박형욱,김용기,임동명,윤신의,최봉남 朝鮮大學校 附設 醫學硏究所 1992 The Medical Journal of Chosun University Vol.17 No.1

The authors observed the clinical findings of 99 cases of traumatic drum perforations, who visited the department of otolaryngology of Chosun University Hospital and KwangYang Hospital from January 1988 to August 1991 The results obtained were as follows; 1) As an etiologic factor, the indirect trauma occupies the most case (79.8%), out of which the most cases is by assault. 2) Age distribution indicates 30 decade(32.3%) and 20 decade(26.3%) in the declining order and sex distribution indicates male to female is 1;1.3. 3) On occupation, house wife is the most frequently involved (35.4%) and officials & students are in the next order. 4) Most common complaint is Hearing impairment and the next complaints are tinnitus, otalgia and hemorrhage in order. 5) The most frequent site of perforation is the central portion of anteroinferior and posteroinfehor quadrant, Gradel in size and triangular shape are common. 6) Seasonal variation indicates that the most frequent occurence of perforation is on summer. 7) Average 25-35㏈ of hearing loss is most common, and the degree of hearing loss is well correlated with the size of perforation. 8) Two way of therapeutic measure are compared. a. stimulating with trichloroacetic acid ; spontaneously healing in 22 cases (22.2%) b. closing procedure with paper patch ; healing in 68 cases (68.7%) 9)The overall healing time is within 2 months in the most of case (about 80%).

지역사회에서 형성된 사회적 지지와 근로자의 사회심리적 스트레스간의 관련성

임화영,김형수,최영환,장성훈,이건세,정최경희,오원기,최재욱,정춘화 대한산업의학회 2006 대한직업환경의학회지 Vol.18 No.4

Objective: This study was performed to examine the relationship between community-based social support and psychosocial distress in workers. Methods: The study subjects were 596 workers recruited from 11 companies in Chungju city. A structured questionnaire was used to assess sociodemographics, health-related behaviors, job characteristics, job stress, work-based social support, community-based social support and level of psychosocial distress. Results: Hierarchical multiple regression analysis showed that workers with no chronic disease, exercise and sufficient sleep had a higher score of psychosocial distress than those with chronic disease, no exercise, and not enough sleep. Coworker's work-based social support and community-based social support were negatively associated with psychosocial distress. The R square value of total independent variables on psychosocial distress was 0.409, and that of community-based social support on psychosocial distress was 0.052. Conclusion: This study showed that community-based social support served as a protective factor against psychosocial distress in some workers. We recommend the establishment of a worksite stress reduction program in occupational level as well as community-based social support.

소규모 제조업에서 재해발생과 사업장 특성간의 관련성 분석

이건세,김형수,,장성훈,정최경희,오원기,최재욱,이관형,오지영 大韓産業醫學會 2006 대한직업환경의학회지 Vol.18 No.2

목적: 소규모 제조업 사업장의 재해 발생 유무에 따른 사업장 조직 특성을 비교하여 재해 발생과 관련된 요인을 사업장 수준에서 파악하고자 하였다. 방법: 한국산업안전공단이 실시한 2004년도 산업안전 보건 동향조사 자료 중 5인 이상 50인 미만 제조업 1,886개 사업장(가중치를 부여하여 추정한 모집단 사업장은 65,921개)의 재해(산재 및 공상, 경상 포함) 발생 여부와 사업장의 조직 특성(일반적 특성, 고용특성 및 산업안전보건 특성)간 다변량 분석을, 사업장의 일반적 특성은 지역, 산업형태, 업종 등이며, 고용특성은 전체 근로자중에서 생산직 근로자의 분포, 여성근로자의 분포, 1주일 평균 근로시간, 교대근무 등이며, 산업안전보건 특성은 안전관리자/보건관리자의 선임형태, 산업안전보건위원회, 노동조합, 매월 정기안전보건교육시간, 안전보건관리 규정, 안전보건활동 점수, 안전문화 점수 등이다. 결과: 다변량 분석결과 재해가 발생한 사업장이 갖는 특성은 다음과 같았다. 첫째, 사업장의 일반적 특성에서 지역별로는 경인권에 비해 전라권, 산업형태 면에서 원청에 비해 사외협력업체, 업종별로는 전자부품/통신에 비해 코크스/석유정제업, 목재/나무제품업, 음식료품, 조립 금속제품에서 위험도가 높았다. 둘째, 사업장의 고용 특성에서는 전체 구성원 중에서 생산직 근로자가 증가할수록 재해발생 사업장이 유의하게 증가하였으며, 여성근로자의 증가할수록 재해발생 사업장이 유의하게 감소하였다. 주당 근무시간이 증가할수록 재해 발생 사업장이 유의하게 증가하였으며, 교대 근무와 사업장의 재해발생과는 유의한 관련성이 없었다. 셋째, 사업장의 산업안전보건 특성에서는 안전관리자가 전임으로 근무할수록, 산안전보건위원회가 활발히 활동할수록, 노동조합이 설립될수록, 안전보건규정이 갖추어지지 않을수록, 정기보건교육시간이 많을수록, 안전문화수준이 낮을수록 재해발생 사업장이 유의하게 증가하였다. 결론: 소규모제조업에서 사업장의 조직 특성에 따라 사업장 재해율이 다름을 확인할 수 있었으며, 이는 산업재해의 예방을 위해서는 근로자 요인이외에도 사업장 수준에서의 관련요인에 대한 접근이 필요함을 의미한다. Objective: This study evaluated the relationship between injury occurrence and workplace organization in small-sized, manufacturing factories in Korea. Methods: Using data from the 2004 Occupational Safety and Health Survey in Korea, this study compared workplace organizational factors (general characteristics, employee characteristics and health and safety characteristics) with injury occurrence of 1,866 small-sized, manufacturing factories (65,921 population factories after weighting). General characteristics of factories comprised location, type and classification of industry. Employee characteristics comprised proportion of manual workers and female workers, average working hours per week and shiftwork. Health and safety characteristics comprised type of safety and health manager, committee for occupational safety and health, labor union, health and safety regulation, monthly health and safety training time, score of health and safety activity and score of safety culture. Results: The following characteristics of injury-occurrence in small-sized, manufacturing factories were determined by multivariate analysis. In terms of general characteristics, the risk of injury-occurrence was higher in Jeolla area than Gyeongin area in outside associate than other enterprises and in coke, refined petroleum products and nuclear fuel, wood and products of wood, food products and beverages and fabricated metal products, except machinery and furniture industries than television and communication equipment and apparatus industries. In terms of employee characteristics, injury-occurrence significantly increased in factories with greater proportion of manual worker and with a higher rate of working hours per week. But significantly decreased in factories with a higher proportion of female workers. In terms of health and safety characteristics, injury-occurrence significantly increased in factories with a self-appointed safety manager, with unorganized union, with a more active committee for occupational safety and health, with unimplemented health and safety regulation, with longer monthly safety and health training time, and with a lower score of safety culture. Conclusions: This study demonstrated that several factors of workplace organization were significantly related with injury-occurrence in factories. These findings are supposed to raise the need for making effort in workplace organization to improve injury prevention.

立地特性別 Asbestos의 環境濃度

유영식,김종규,민달기,김남천,이형춘,최한영,김을환,우세홍,이상건 서울保健大學 1989 論文集 Vol.9 No.1

포사맥스 정(알렌드론산나트륨 70mg)에 대한 대웅 알렌드로네이트 정 70mg의 생물학적 동등성

이예리,정선경,양승권,최기호,신용철,전형규,강승우,이희주 한국약제학회 2006 Journal of Pharmaceutical Investigation Vol.36 No.2

Characterization of Supported Cobalt Catalysts by TPR and TPD

Choi, Hyeong Ki,Choi, Jong Oh,Choi, Jeong Gil,Jung, Moon Ki,Oh, Hyun Gyun 한국공업화학회 1997 Journal of Industrial and Engineering Chemistry Vol.3 No.3

The surface properties of cobalt catalysts supported on A1₂O₃, SiO₂, and TiO₂ were investigated using temperature-programmed reduction and desorption. Effects of different supports, metal loading, and preparation condition on cobalt catalyst properties were also evaluated. The activation energy of reduction increased in the following order: Co/TiO₂<Co/A1₂O₃<Co/SiO₂. For different metal loadings, the catalyst with the lower loading was less readily reducible than that with the higher metal loading. This was confirmed using the results from measurements of particle size, amount of CO desorbed and catalytic activity. While carbon monoxide adsorption at room temperature produced four carbon monoxide desorption peaks for Al₂O₃-supported cobalt catalyst, one carbon monoxide desorption peak was observed for cobalt catalysts supported on SiO₂ and TiO₂. Based on the results on the amount of carbon monoxide desorbed, it was considered that multiple desorption peaks on Co/A1₂O₃ catalyst might be due to the morphological changes between cobalt oxide and alumina support, and the stabilization of Co^(2+) by SiO₂ support and the concept of SMSI (strong metal-support interaction) were suggested to explain the results for Co/SiO₂ and Co/TiO₂ catalysts, respectively.

Comparison of Lower-Limb Alignment in Patients with Advanced Knee Osteoarthritis: EOS Biplanar Stereoradiography versus Conventional Scanography

Hyeong-Uk Choi,Du-Han Kim,Si-Wook Lee,Byung-Chan Choi,Ki-Cheor Bae 대한정형외과학회 2022 Clinics in Orthopedic Surgery Vol.14 No.3

Background: Accurate measurement of the lower limb alignment is one of the most crucial factors in advanced knee osteoarthritis patients scheduled for surgery. Recently, EOS biplanar stereoradiography with three-dimensional reconstruction was developed. The purpose of this study was to compare radiographic parameters between conventional scanography and EOS in patients with advanced knee osteoarthritis who need surgical treatment. Methods: A total of 52 consecutive patients (104 knees) with bilateral knee osteoarthritis of advanced stage (Kellgren-Lawrence [KL] grade 3 or 4) were retrospectively reviewed. We measured the hip-knee-ankle angle (HKA) on conventional scanograms. In EOS, we measured HKA, hip-knee-shaft angle, mechanical lateral distal femoral angle, and mechanical medial proximal tibial angle. To evaluate sagittal and axial plane alignment, knee flexion angle (KFA), and knee joint rotation (KJR) were also measured. Results: Ninety knees were KL grade 4, and 14 knees were grade 3. The average HKA was 10.14° ± 6.16° on conventional scanograms and 11.26° ± 6.21° in EOS. HKA was greater in EOS than on conventional scanograms, and the difference (1.12°; range, −1.07° to 3.22°) was statistically significant (p < 0.001). Significant correlations were observed on the difference in HKA and mechanical medial proximal tibial angle (r = –0.198, p = 0.044), KFA (r = 0.193, p = 0.049), and KJR (r = 0.290, p = 0.003). In multivariable linear regression analysis, the difference in HKA had significant relationship with KFA (β = 0.286, p = 0.003) and KJR (β = 0.363, p < 0.001). Conclusions: HKA measured on conventional scanograms and in EOS differed significantly and the difference had a significant correlations with KFA, KJR, and medial proximal tibial angle. Surgeons can consider these results before orthopedic surgery in patients who have advanced knee osteoarthritis.

Development of a Coarse Spherulite in Poly ( vinylidene fluoride ) / Poly ( methyl methacrylate ) Blends

Choi, Hyeong Ki,Lee, Yong Moo,Lee, Chang Hyung,Kim, Joon Hyung 한국공업화학회 1998 Journal of Industrial and Engineering Chemistry Vol.4 No.1

The spherulite formation in poly(vinyliden fluoride) (PVDF)/poly(methyl methacrylate) (PMMA) blend was investigated by time-resolved light scattering under H_v (cross-polarized) optical alignment using (CCD) camera system. The final morphology was observed by atomic force microscopy (AFM) images and optical microscope (OM). The coarse spherulite was observed at high temperature (162 ℃) by OM, whereas the compact spherulite was appeared at low temperature (148℃). In the compact spherulite, the spherulite radius linearly increased with time. The order parameter defined by the sharpness of Hv scattering profile monotonously decreased with crystallization. In the coarse spherulite, the spherulite linearly grew, stopped growth for a while, and then restarted i.e., a pause in growth was observed. It was ascribed to the rejection of the noncrystallizable component (PMMA) at spherulite growth front. The order parameter initially increased, attained a maximum, and then decreased. Time at maximum point was consistent with onset time of a pause in the spherulite growth. Thus, a maximum in order parameter may be ascribed to the rejected PMMA at the spherulite growth front. A supplemental evidence for these results was provided by the morphology observation of the AFM