농촌지역 노인들의 우울증상에 관련된 요인들의 특성

송미숙,전기홍,송현종,김정은,박승구,신상건,이동훈,정성현,최연주,최완철,최민규,황재철,홍지만 아주대학교 1997 아주의학 Vol.2 No.2

This study was performed to identify risk factors for depression among the elderly in a rural area. A survey was done for the elderly living in Gosam-myenn, Ansung-kun during the period of July 28, 1997 and July 30, 1997. Demographic and sodoeconornic characteristics, and functional and health Status were assessed using a structured questionnaire, and the level of depression was measured by GDS score. The data obtained were analyzed by frequencies, percentage, t-test, ANOVA, and multiple regression, and the results were as follows: 1. The total sample consisted of 133 elderly. Of them, 47 elderly (35.4%) showed significant depressive Symptoms. 2. The GDS score was the highest for the group over 85 years of age (p < 0.05). Those living alone or widowed showed lower GDS score than those living with someone or married (p < 0.05). 3. The GDS score was the highest in the absolutely dependent group, followed by the partially dependent group, and the independent group (p < 0.01). The elderly who perceived their health Status as excellent showed the lowest GDS score. In contrast, those who had more than five chronic diseases showed the highest GDS score. 4. The elderly receiving financial and emotional support from their family or friends showed lower GDS score compared to those without any support. 5. The economically dependent group showed higher GDS score than that of independent group. 6. The elderly who involved in leisure activities showed lower GDS score than those without any involvement. 7. In terms of risk factors for depression, we found that perceived health Status, subjective economic Status, leisure activities, living arrangement and financial support were inversely associated with GDS score, whereas labor support was positively associated with GDS score. Based upon the above findings, this study suggests that these risk factors for depression in the elderly should be taken into consideration for a comprehensive mental health program for the elderly living in the rural area.

중소기업형 CIM시스템 구축을 위한 생산계획수립 및 실적파악 모듈

최후곤,신완선,장중순,서준성,여명구,안동근,김진봉 成均館大學校 科學技術硏究所 1996 論文集 Vol.47 No.2

This study Focuses on developing several modules involved in an integrated production information system for medium- or small-sized industries. The modules of order management, quality control, production scheduling, and shop management are executed for an example case industry. The potential values of this research includes that the major information modules to collect, analysis, and display production data and shop data for constructing the computer integrated manufacturing system(CIMS) are programmed with various features of medium- or small-sized industries

100 kVA GTO 전압원 인버터를 사용한 정지형 무효전력보상기

최남섭,조국춘,정구호 여수대학교 1998 論文集 Vol.13 No.2

A stactic VAR compensator using 100 kVA three-level GTO voltage source inverter is presented for high voltage, high power application. The phase angle of the voltage source inverter is controlled so as to compensate the reactive power of some three-phase load. This paper deals with the following topics: system description, circuit DQ modelling, main controller, power circuit. The experimental results show good characteristics for var compensation.

갈바닉 전류를 이용한 철근부식 탐사기술에 관한 연구 : Part 2: 콘크리트에서 행한 전기화학적 시험 Part 2: Laboratory Electrochemical Testing of Sensors in Concrete

최윤석,박진택,김정구 대한금속재료학회 2005 대한금속·재료학회지 Vol.43 No.1

The correlation between sensor output and the corrosion rate of steel bar was confirmed in concrete environment. Monitoring of open-circuit potential, linear polarization resistance (LPR) measurement and electrochemical impedance spectroscopy (EIS) were used to evaluate the corrosion behavior of steel bar embedded in concrete. Also, galvanic current measurements of designed sensors were conducted to obtain the charge of sensor embedded in concrete. In this study, the results of corrosion behavior of reinforcing steel showed a consistence among the data obtained by open-circuit potential monitoring, LPR and EIS measurements. Steel/copper sensor showed a good correlation in concrete environment between sensor output and corrosion rate of steel bar. However, there was no relationship between steel/stainless steel sensor output and corrosion rate of steel bar due to the low galvanic current output. Through the relationship between the steel/copper sensor output and the corrosion rate of reinforcing steel, real corrosion damage of the reinforcing steel can reliably be detected. (Received October 29, 2004)

한국산 배의 Polyphenol 화합물군이 쥐의 면역기능에 미치는 영향

최희진,한호석,박정혜,배종호,우희섭,안봉전,배만종,김현구,최청 한국식생활문화학회 2003 韓國食生活文化學會誌 Vol.18 No.4

This study was conducted to investigate immunofunctional activity of the polyphenol fractions isolated from Korean pear. In the experimental of Rosette forming cell, the results showed that all the polyphenol fractions enhance the cell count compared with the control group. Especially polyphenol fraction II and III showed highly significant effect on Rosette forming cell, and allergy inhibition. After antigen challenge, histamine content of blood of the polyphenol groups was lowered to near the normal group.

면외변위의 정량적 계측을 위한 ESPI와 Shearography의 비교

최정구,김경석,장호섭,정성욱 朝鮮大學校 機械技術硏究所 2005 機械技術硏究 Vol.8 No.2

Electronic Speckle Pattern Interfrometry is a common method for measuring out-of-plane displacement and in-plane displacement and applied for vibration analysis and strain/stress analysis. However, ESPI is sensitive to environmental disturbance, which provide the limitation of industrial application. On the other hand, Shearography based on shearing interferometer can directly measure the first derivative of out-of-plane displacement, which is insensitive to vibration disturbance. This paper proposes the out-of-plane displacement extraction technique from results of Shearography by numerical processing and measurement results of ESPI and Shearoraphy are compared quantitatively.

Cr, Co, Cu, Ni와 Ca의 첨가에 따른 지하매설배관의 전기화학적 특성에 관한 연구

최윤석,신동호,심재주,김정구 대한금속재료학회 2005 대한금속·재료학회지 Vol.43 No.1

Aqueous corrosion characteristics of low carbon steel with small amounts of Cr, Co, Cu, Ni and Ca, in synthetic groundwater was studied by electrochemical corrosion tests (potentiodynamic test and electrochemical impedance spectroscopy (EIS) measurements) and analytical techniques. Neither carbon steel nor newly alloyed steels showed passive behavior in this synthetic groundwater. Newly alloyed steels, containing Cr-Co, Cr-Cu-Ni and Cr-Cu-Ni-Ca showed higher corrosion resistance than carbon steel in the potentiodynamic tests. EIS measurements showed that the Nyquist plot presented two time constants. The high frequency resistance component (R_(rsut)) and low frequency resistance component (R_(et)) were affected by the alloying elements. The polarization resistance (RP= R_(et) +Ra) of steels could be clearly ranked as Cr-Cu-Ni-Ca steel >> Cr-Cu-Ni steel > Cr-Co steel > carbon steel. Results of surface analyses (XPS and EPMA) showed that Cr and Cu were concentrated in the inner region of rust. However, Co and Ni were uniformly distributed all over the rust layer. These alloying elements improved corrosion resistance of low alloy steel in synthetic groundwater. Especially, Cr-Cu-Ni-Ca steel had the lowest corrosion rate due to the inner rust film formation during the initial stage of corrosion, which suggested a potential for substituting carbon steel in soil environment (Received October 29, 2004)

상수도 배관의 부식감지시스템 개발 (Ⅰ)

최윤석,김정구 대한금속재료학회 2003 대한금속·재료학회지 Vol.41 No.10

In order to develop a new corrosion sensor for detecting and monitoring the corrosion of buried pipeline, sensor element design and the correlation of its output to corrosion rate of steel pipe itself were evaluated by laboratory test methods in synthetic groundwater. It uses well-known principles of galvanic corrosion and consists of two dissimilar metals (anode and cathode) installed on the buried pipeline. In this paper, two types of electrochemical probes were used: galvanic cells containing pipeline steel (CS)-copper (Cu) and pipeline steel (CS)-type 304 stainless steel (SS) couples. The corrosion behavior in synthetic groundwater for the different electrodes was investigated by potentiodynamic test. The galvanic corrosion test was accomplished by a zero resistance ammeter technique. Weight loss measurements were conducted to obtain the corrosion rates of pipeline steel in synthetic groundwater. The correlation between galvanic current and corrosion rate was obtained by galvanic current measurement and corrosion rate measurements. The results of the potentiodynamic test indicated that copper exhibited an active corrosion behavior, while stainless steel demonstrated spontaneous passivation. In galvanic corrosion tests, the galvanic current of copper-steel couple was higher than that of other couple. The comparison of the sensor output and corrosion rate revealed that a linear relationship was found between the probe current and the corrosion rate. Especially, a better linear quantitative relationship was found between the Cu-CS probe current and the weight loss data of the pipeline steel coupons. In addition, the Cu-CS probe is more suitable for high resistance soil than SS-CS probe, due to the high current output.

이중보온 온수배관의 부식피로균열 특성에 관한 연구

최윤석,김정구,정민경,이훈 대한금속재료학회 2004 대한금속·재료학회지 Vol.42 No.2

The corrosion fatigue properties of thermally insulated pipeline were investigated in synthetic groundwater by electrochemical test, corrosion fatigue test and SEM analysis. Since the potential difference between the weldment and the base metal was small, the pipeline steel was not susceptible to galvanic corrosion. No fatigue limit was apparent for corrosion fatigue testing with remarkable reduction of fatigue lifetime. The effects of insulation and stress on the corrosion fatigue resistance of pipeline steel were studied through linear polarization resistance (LPR) and electrochemical impedance spectroscopy (EIS) during corrosion fatigue testing. The result of LPR measurement indicated that the corrosion rate was determined not by the water content of PUR foam but by the magnitude of applied stress. The better corrosion fatigue property of the insulated steel was attributable to the formation of a protective rust layer under the insulation, which reduced the acceleration of corrosion process and the propagation of fatigue crack. This was confirmed by the results of EIS measurements and SEM observation.

상수도 배관의 부식감지시스템 개발 (Ⅱ)

최윤석,신동호,김상현,김정구 대한금속재료학회 2005 대한금속·재료학회지 Vol.43 No.4

In order to develop a new corrosion sensor for detecting and monitoring the corrosion of buried pipeline, the electrochemical property of sensors and the correlation of its output to corrosion rate of steel pipe, were evaluated by electrochemical methods in synthetic groundwater, two soils of varying resistivity (5,000 ohm-cm, 10,000 ohm-cm), and synthetic tap water. In this paper, two types of electrochemical probes were used: galvanic cells containing of pipeline steel-copper and pipeline steel-stainless steel (Type 304). The results of EIS measurement indicated that the sensor current was inversely related to sensor resistance, which was governed by the corrosion behavior of cathode. In galvanic corrosion tests, the galvanic current of Cu-CS probe was higher than that of SS-CS probe. The comparison of the sensor output and corrosion rates revealed that a linear relationship was found between the probe current and the corrosion rates. A good linear quantitative relationship was found between the Cu-CS probe current and the corrosion rate of pipeline steel coupons in the soil resistivity of 5,000 ohm-cm, and synthetic tap water. In the case of the soil resistivity of 10,000 ohm-cm, although the SS-CS probe showed a better linear correlation than that of Cu-CS probe, the Cu-CS probe is more suitable than SS-CS probe, due to the high current output. (Received February 1, 2005)