곡관덕트에서 난류정상유동의 벽면전단응력분포와 입구길이에 관한 실험적 연구

손현철,이홍구,김대욱,김명호,박길문 朝鮮大學校 機械技術硏究所 2000 機械技術硏究 Vol.3 No.1

In this paper, an experimental investigation of characteristics of developing turbulent steady flows in a square-sectional 180°curved duct is presented. The experimental study using air in the square-sectional 180°curved duct is carried out to measure entrance length and wall shear stress distributions by using Laser Dopper Velocimeter(LDV) system with data acquisition and processing the system of FIND6260 software at 7 sections from the inlet(ø=0°) to the outlet(ø=180°)in 30°intervals of the curved duct. The results obtained from experimental studies are summarized as follows : (1) The critical Dean number of turbulent steady flow is about 560. (2) The value of the wall shear stress becomes minimum in the inner wall and gradually increases toward the outer wall where it becomes maximum. (3) The entrance length of the turbulent steady flow is shorter than that of the traditional steady flow, reaching the vicinity of bend angle 90°

曲管덕트 입구 영역에서 遷移定常流動의 速度分布와 壁面剪斷應力分布에 관한 연구

손현철,김명호,박길문 朝鮮大學校 機械技術硏究所 1998 機械技術硏究 Vol.1 No.1

In the present study, the flow characteristics of developing transitional steady flows in a square - sectional 180° curved duct are investigated experimentally. The experimental study for air flow in a square - sectional 180° curved duct is carried out to measure the axial velocity profiles and wall shear stress distributions by using Laser Doppler Velocimeter (LDV) system with data acquisition and processing the system of FIND software at 7 sections from the inlet (ø=0°) to the outlet (ø=180°) in 30° intervals of a curved duct. The results obtained from experimental studies are summarized as follows : (1) The critical Dean number of transitional steady flow is about 450. They show that critical Reynolds number in a curved duct is larger than that in a straight duct. (2) For transitional steady flows, the maximum velocity position of axial velocity profiles begins to incline toward the outer wall from ø=30°bended angle, velocity profiles in center of the duct have lower value than those of the inner and outer walls because of the centrifugal forces. (3) Wall shear stress distributions of transitional steady flows are increased at the entrance region because of increasing shear stress and pressure loss by the influence of flows.

수입 외국산 모발세정용 화장품의 중금속 농도에 관한 연구

문정아,문덕환,박명희,안진홍,김종은,손병철,김대환,이창희,김휘동,이채언 인제대학교 백병원 2002 仁濟醫學 Vol.23 No.5

Objective : For the purpose of preparing the fundamental data and preventing the health impairment due yo heavy metals in hair cleaner. Methods and Material : The author determined the concentration of heavy metals(Fb, fn, Cr, Ni and Cu) in hair cleaner with flameless atomic absorption spectrophotometer. Results : The results were as follows : 1. The mean concentration of heavy metals in total hair cleaner were 0.046㎍/g for Pt, 0.O67㎍/g for Mn, 0.069㎍/g for Cr, 0.046㎍/g for Ni, and 0.022㎍/g for Cu, respectively. 2. There was not statistically significant difference to mean concentrations of each heavy metal in hair cleaner by producing nation. 3. The highest mean concentration of each heavy metal in hair cleaner by type of use were 0.140㎍/g for Mn in sensitive hair cleaner(p<0.05), 0.053㎍/g for Cu in others products(p<0.01). 4. The mean concentration of heavy metals in hair cleaner by type of hair cleaner were high at 0.O54㎍/g for Pb in shampoo products(p<0.O5), 0.120㎍/g for Cr and 0.06㎍/g for Cu in combination products(p<0.01). 5. The mean concentration of heavy metals in hair cleaner by acidity were high at 0.056㎍/g for Pb, 0.124㎍/g for Cr, and 0.032㎍/g for Cu in alkali products (p<0.05). 6. Correlation coefficient of heavy metal concentration in hair cleaner were 0.175 for Pb and Cr, 0.165 for Pb and Mn, 0.824 for Cr, and Mn, 0.189 for Cr, and Ni, 0.406 for Cr, and Cu, 0.197 for Mn and Ni, and 0.375 for Mn and Cu(p<0.05). 7. Exposure amount of heavy metals per when we used lOg of hair cleaner (onetime using amount) were 0.46㎍ for Pb, 0.67㎍ for Mn, 0.69㎍ for Cr, 0.46㎍ for Ni, and 0.22㎍ for Cu, respectively. Conclusion : As above results, there was very low level concentration of heavy metal in hair cleaner but we are using the hair cleaner everyday, therefore we can exposed to heavy metals as cronic exposure so the author suggest to prepare the program of preventing the health impairment due to heavy metals.

Electron Cyclotron Resonance O_2 Plasma에서 증착한 규소 산화 박막의 특성

안명환,서문석,장재선,서성모,이기방,윤창주,이형재,남기석,최규현,손춘배,김용섭,강석희 全北大學校 基礎科學硏究所 1994 基礎科學 Vol.17 No.-

규소 산화막을 ECR-CVD(electron cyclotron resonance-chemical vapor deposition) 증착방법으로 5인치 기판위에 상온에서 증착하고, 증착공정조건인 증착율, 기판온도, 마이크로파의 세기변화 및 플라즈마 혼합기체의 비에 따른 규소 산화막의 특성을 조사하였다. 또한 산화막의 구조적인 특성을 비교하기 위해 FTIR을 이용하여 ECR-CVD 증착한 산화막, RPE-CVD(remote plasma enhanced-CVD) 증착한 산화막 및 열 산화막의 stretching frequency를 측정하였다. 측정된 결과 ECR-CVD로 증착된 산화막이 구조적인 면에서 열 산화막과 거의 같음을 보였다. ECR-CVD로 증착된 산화막의 전기적인 특성을 전류-전압 및 축전-전압 측정에의하여 분석하였다. 축전된 산화막의 전기적인 특성은 산화막의 전하 밀도는 1×10 exp (11)/㎠이였고, 평균 절연 파괴 전압은 약 6 MV/㎝이다. We have grown thin films of SiO_2 at room temperature by using an ECR-CVD system and have investigated the changes in the properties of the deposited films with changes in the processing conditions such as the deposition rate, the substrate temperature, the microwave power and the plasma gas mixing ratio. We also measured the stretching frequency of three kinds of oxides, and ECR-CVD-grown oxide, a PECVD-grown oxide, and a thermally grown oxide, using FTIR analysis to compare their structural properties. The result shows that the structural properties of the ECR-grown oxide are similar to those of the thermally grown oxide. Additionally, the electrical properties of the ECR-grown oxide were investigated by using current-voltage and capacitance-voltage measurements. These electrical results indicate that the oxide charge density and the average breakdown voltage are 1×10 exp (11) ㎝^-2 and 6 MV/㎝, respectively.

간호실무에서 신봉이론(Espoused theories)에 대한 탐색적 연구

서문자,김혜숙,이은희,박영숙,조경숙,강현숙,임난영,김주현,이소우,조복희,이명하,지성애,하양숙,손영희,권성복,김희진,추진아 성인간호학회 2001 성인간호학회지 Vol.13 No.1

As a nursing practice involves nurses' actions in a specific context of health care, this study has focused on exploring the espoused theories in nursing practice within the action science perspectives, Espoused theories are the belief, principles, and rationale expressed by the practitioner as guiding her/his actions in a situation of practice. The data were analysed qualitatively and 25 elements of espoused theories of nursing action were identified and clustered into 6 categories. The 25 elements of espoused theories are as follows: The clinical nurse worked in wholistic and individual nursing, focussed on the patient's needed, comfort and supportive nursing (5 theories of nursing goal) ; excellent skills, knowledge based, assessment and data collection, explaining, educating or a scientific basis(6 theories of nursing intervention): advocacy, value oriented, treatment, account- ability and commitment(4 theories of nursing ethics) ; human respect. partnership, trust(3 theories of patient-nurse relationship) : knowledgable, accumulated clinical experiences and personally lived experiences. positive perspectives(4 theories of nurse), role of intervention. rewarding peer relationship(3 theories of situations) The above mentioned espoused theories are similar to that of nursing textbooks which students learned through basic nursing education and almost the same as the Acts ofa Nurse in Korean. However, we are doubtful whether nurses actually do as they think. Therefore. it is recommended to review the theories-in-use in order to and any discrepancies between the espoused theories and the reality of nursing actions

소규모사업장 용접근로자들의 소음·용접흄·망간 노출에 관한 연구

김동구,문덕환,이채관,박명희,함성애,손병철,김대환,이창희,김휘동,이채언 인제대학교 백병원 2002 仁濟醫學 Vol.23 No.5

Objective : This study was conducted for the purpose of investigating the level exposure of welders to noise, welding fume and Manganese(Mn) related to this process. Methods and Material : All subjects in this study were welders engaged in CO2 arc and coated arc welding process especially in small-scale enterprises classified by type of manufacture of ship building, repairing and of other fabricated metal products, which is located in Gimhae and Milyang of Kyeongsang province in south Korea. Air sampling of welding fume was measured, shipped and analyzed on the basis of national institute for occupational safety and health(NIOSH) method in U.S. and work environment measurement method established in south Korea. To measure Noise in the work environment, Noise dosimeter was used on the basis of work environment measurement method established in south Korea. Result : This study was performed during a period from January, 2000 to December, 2001 and Results were as follows: 1. Noise level measured in this work environment was higher than national criteria for permissible exposure limit on health examinations related to hearing loss. 2. The concentration of welding fume and Mn in manufacture of ship building and repairing was higher than those in manufacture of other fabricated metal products. 3. In conditions of existing in ventilation system installed and operated, the concentration of welding fume and Mn was slightly lower than those of not existing. 4. In conditions of existing in sufficient air supply from out door into the work place relied on natural exhaust system, the concentration of welding fume and Mn was slightly lower than those of in not sufficient. 5. In all subjects, a rate of wearing ear plug and respiratory mask for dust and fume was lower than that of not wearing. Conclusion : According to above results, this study suggests that more positive work environment managements such as the use of portable local ventilation system, the supply of highly qualified personal protective equipment, and consecutive education and training related to health protection should be need to acquire suitable health protection program for welders engaged in small-scale enterprises in Korea.

퍼머제의 중금속 농도에 관한 연구

윤복연,문덕환,박명희,황용식,함성애,손병철,김대환,이창희,김휘동,이채언 인제대학교 백병원 2002 仁濟醫學 Vol.23 No.5

Objective : This study was conducted to prepare the fundamental data on heavy metal concentration in hair permanents agents and to prevent the health impairment due to heavy metal. Methods and Material : The author determined of 5 heavy metals(Pb, Cr, Mn, Ni, and Cu) concentration hair permanent agents in the market with flameless atomic absorption spectrophotometer. Results : The results were as follows: 1. The geometic mean concentrations of total subjects were 0.04㎍/g for Pb, 0.09㎍/g for Cr, 0.06㎍/g for Mn, 0.03㎍/g for Ni, and 0.04㎍/g for Cu. 2. The most highest mean concentrations of heavy metals in hair permanent agents by using type were Cr for wave agent and straight cream agent, Cu for setting iron agent, Cr and Cu for coating perm agent. 3. Metal most hlghest mean concentrations of heavy in hair permanent agents by type of color was green for Cu. 4. The mean concentration of Cu among 5 heavy metals in hair permanent agents by marker was most highest. 5. There was most statistically significant difference on mean concentration in hair permanent agents between domestic and foreign products. 6. The exposure amount of heavy metal concentration by one time using the permanent agent were 4.O㎍ for Pb, 9.O㎍ for Cr, 6.0㎍ for Mn, 3.O㎍ for Ni and 4.0㎍ for Cu. Conclusion : As above results author suggest to prepare the preventive program of health impairment due to heavy metal by long term chronic exposure to who were using the hair permanent agents hair designer and customers.

미용사들의 이직욕구에 관한 연구 : 직무스트레스, 근골격계 증상을 중심으로 Focusing on Musculoskeletal Symptoms and Occupational Stress

서은경,문덕환,박명희,김정원,황용식,손병철,김대환,이창희,김휘동,이채언 인제대학교 백병원 2002 仁濟醫學 Vol.23 No.5

Objective : This study was conducted to prepare the fundamental data on desire of job transfer in hairdresser and prevent the health impairment of hairdresser due to occupational stress and musculosketetal symptoms. Methods and Material : The author surveyed the desire of job transfer and muscurlosketetal symptoms and occupational stress with self-reported questionnaire to 105 hairdresser who were working in beautyshop of Busan area and also 121 student in department of cosmestology as control group. Results : The results were as follows: 1. The rates of self reported symptom were 81.0% for shoulder, 72.4% for back, 67.6% for knee, 58.1% for hand in hairdresser, and 79.3% for shoulder, 71.9% for back, 66.9% for neck, 64.5% for hand and knee in student. 2. The rate of musculoskeletal symptom by NIOSH criteria was 36.2% in hairdresser, it was higher than student group(24.8%)(p<0.1). Occupational stress of the groups by occupational stress category was high as decision latitude, skill discretion, psycological job demand, decision authority in order. 3. The results of logistic regression of related varibles with desire of quitting job by logistic regression were statistical bordline significance between desire of quilting and social support(p<0.1). Conclusion : As above results, the author suggest to prepare the preventive program an musculoskeletal symptoms in hairdresser, especially shoulder, and also to control the occupational stress to hairdresser in beauty shop because occupational stress can be a factor of desire of quitting job.

기체 방사성 물질 제거를 위한 첨착 활성탄 필터 시스템 성능에 관한 연구

김대욱,손현철,이명석,이석범,박길문 朝鮮大學校 機械技術硏究所 1999 機械技術硏究 Vol.2 No.1

This paper presents an application of impregnated activated carbon and impregnated activated carbon filters. They are used for the removal of gaseous radioactive materials at radioactive material handling facilities such as nuclear power plants and research facilities. High adsorption efficiencies as well as stability are required for them to remove hazardous radioactive gases such as activated free iodine released during normal operation or accident condition. This research was initiated to enhance the independence of nuclear industry and raise the level of nuclear technology to that of the leading nuclear nations. By attaining the capability of design and development of HVAC system, national technological competitiveness can be achieved. Also, the ground for technology export will be hardened. Therefore, it is well timed to initiate the project to develope those filter systems domestically utilizing all the relevant technologies available.

동북아 고대 해상무역제도에 관한 고찰 : 장보고의 통상네트워크와 관련하여

윤광운,박명섭,김재승,손성문 국제무역학회 2002 국제무역연구 Vol.8 No.1

본 연구는 통상사적 측면과 무역상무론적 관점에서 9세기 동북아 해상교역환경과 장보고의 해상무역의 실체를 규명함으로써 오늘날 동북아지역간의 통상협력을 통한 발전방향을 모색하는데 그 목적이 있다. 이를 위해서 본 연구에서는 9세기 통일신라, 중국의 당나라 및 일본을 중심으로 한 동북아지역의 해상교역제도의 일반환경과 발전요소를 분석하고, 장보고 해상무역의 특성 및 교역관행 그리고 물적·인적 네트워크를 통한 동북아 통상네트워크 기반을 분석하고 있다. 특히 동북아지역 통상네트워크의 구축을 기반으로 하고 있는 장보고 해상교역의 특성으로 우선 지리적으로는 고대 동북아지역을 중심으로 한 통일신라의 청해진과 중국 당대의 산동성 법화원 그리고 일본의 하까다지점을 연결하는 해상교역네트워크를 구축한 점이고 둘째, 해상교역관행으로 주로 중계무역형태와 선불제도관행, 통상정책적 제반활동을 수행한 점과 셋째, 해상교역의 주요 수단으로 신라의 항해술과 당대의 발달된 조선술을 기초로 하고 있음을 알 수 있다. 이러한 점은 해상교역을 통하여 새로운 시장과 제품, 신사고라는 국제교역의 동기를 바탕으로 하여, 오늘날에도 여전히 국제무역의 주요 요인으로서 향후 동북아지역의 새로운 통상환경의 기반을 더욱 촉진할 필요가 있다. The purpose of this paper is to survey the ancient marine trade in Northeast Asian Area and present the directions for developing through the economical cooperations among Korea, China and Japan in Northeast Asian district. In order to achieve of above purposes, this paper investigated the environments of marine trade and the practices of Changbogo's marine trade focus on Silla, Tang in China and Japan in the 9th century. The features of Changbogo's marine trade are as follows: First, geographically, Changbogo constructed marine trade network linking in Silla, Tang, Japan, in the center of ancient Northeast Asian areas Second, Types of marine trade is largely today's intermediary trade Third, His marine trade depended on the technical improvement of navigation and shipbuilding. These things are also central factors of today's international trade and they are necessary to open up a new market through the marine trade.