갈바닉 전류를 이용한 철근부식 탐사기술에 관한 연구 : Part 1: 모사용액에서 행한 갈바닉 센서의 전기화학적 시험 Part 1: Electrochemical tests of galvanic sensors in pore solution

유지홍,박진택,김정구,정란 대한금속재료학회 2003 대한금속·재료학회지 Vol.41 No.8

The correlation between sensor output and corrosion rate of reinforcing steel was evaluated by laboratory electrochemical tests in saturated Ca(OH)_(2) solution with 3.5wt.% NaCl. In this paper, two types of electrochemical probes were developed: galvanic cells containing of steel/copper and steel/stainless steel couples. The corrosion behavior in saturated Ca(OH)_(2) solution with or without 3.5 wt% NaCl addition for the different electrodes was investigated by potentiodynamic test. Weight loss measurement and galvanic corrosion test were conducted to obtain the corrosion rate of reinforcing steel and the charge of sensor in saturated Ca(OH)_(2) solution with 3.5 wt.% NaCl addition, respectively. The results of the potentiodynamic test indicated the possibility of detecting an ingress point of chlorides by measuring the galvanic current. In galvanic corrosion tests, the galvanic current of steel/copper couple was higher than that of steel-stainless steel couple, i.e., the steel/copper sensor is more suitable for high resistance environment. The steel/stainless sensor showed a better linear correlation than the steel/copper sensor. Through the relationship between the sensor system output and the weight loss of steel, real corrosion damage of the steel embedded in concrete can be detected.

1980년대(1981-1990) 전·후반기 피부과 외래환자의 통계적 비교 관찰

은 철,강승구,권상진,정성재,조지형,권철욱,김영진,김재홍 한양대학교 의과대학 1997 한양의대 학술지 Vol.17 No.1

To study the prevalence of common dermatoses 37,638 and 30,286 new outpatients who visited dermatology clinic with Hanyang University Hospital from January 1981 to December 1985 and from January 1986 to December 1990, respectively. Among the 37,638 outpatients in the first 5 years, the total number of male patients were 18,107(48.1%) and female patients were 19,531 (51.9%). Among the 30286 outpatients in the last 5 years, the total number of male patients were 14,705 (48.6%) and female patients were 15,581 (51.4%). In the both periods, the most frequent age groups was 21-30 (27.3%,25.2% respectively). The 15 common dermatoses, bacterial infection, seborreic dermatitis, drug eruption, verruca, syphilis, psoriasis, herpes zoster, and hypopigmentary disorder, in order of frequency. In thelast 5years, dermatophytosis, contact dermatitis, urticaria, acne, other eczema, atopic dermatitis, seborrheic dermatitis, bacterial infection, drug eruption, verruca, gerpes zoster, psoriasis, hypopigmentary disorder, scabies and syphilis were the 15 common dermatoses, as frequency. In both periods, the dermatosis which showed annually increasing tendency was dermatophytosis and those of decreasing tendency was bacterial infection. In the both periods, dermatophytosis, urticaria, bacterial infection, seborrheic dermatitis, verruca, and hypopigmentary disorder occurred most frequently during the summer season, and the incidence of other ecxema, scabies, atopic dermatitis, and herpes zoster increased during the winter season.

만성신부전환자의 구강위생상태에 관한 역학적 조사연구

정호균,박주현,홍지원,강홍구 중앙대부설한국의과학연구소 1991 한국의과학 Vol.23 No.1

화농성 슬관절염이 동반된 수막구균성 수막염 1예

김태연,유진홍,박성환,김연식,임상현,신완식,강문원,정창훈,최문구,강지민 대한화학요법학회 1997 대한화학요법학회지 Vol.15 No.2

저자들은 최근 화농성 슬관절염과 병발한 수막구균성 수막염 1예를 체험하였고, 이는 국내에서 아직 보고되지 않은 드문 예로 사료되어 문헌고찰과 함께 보고하는 바이다. We recently experienced a case of meningococcal meningitis associated with pyogenic arthritis in a 37-year old male patient. Pyogenic arthritis developed in right knee joint during treatment for meningococcal meningitis. He was treated successfully by appropriate antibiotics and arthroscopic irrigation. To our knowledge, such a rare case has not ever been reported in Korea, Hence we report this case with a review of related literatures.

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.

온라인과 오프라인의 적절한 통합을 위한 의사결정 로드맵에 관한 실증연구 : 한국 전통기업의 경우 The Case of Korean Traditional Companies

김인재,황경태,지홍구 한국경영과학회 2002 韓國經營科學會誌 Vol.27 No.1

The wide use of Information Technology(IT),especially the rapid diffusion of the internet, brings us a new paradigm, called "Electronic Commerce," or "Digital Economy." The paradigm is regarded as a business strategy essential to organization' competitive advantages. Because few studies have been shown in the area of e-strategies, especially in the combined strategies of clicks and mortars, a study of this area is required. The main questions of this study are empirically to validate the usefulness and applicability of a decision roadmap and to analyze the situation of Korean firms in the view of the decision roadmap. Major results of the study are as follows; First, there is an evidence that the roadmap can be applied to Korean firms regardless of their industry and size. Second, the usefulness of the roadmap is proved because companies following the directions of the roadmap show high degree of satisfaction with online sales. Their, Korean companies in general do not achieve an ideal integration (or separation), especially in terms of management and operation. In conclusion, this study provides an e-business strategy planner some guidelines about how to achieve right mix of on-line and off-line business.

플라이 애쉬가 콘크리트 구조물의 철근 부식에 미치는 영향

박진택,유지홍,김정구,이재호,이광명 대한금속재료학회 2003 대한금속·재료학회지 Vol.41 No.4

Addition of fly ash has beneficial effects on some mechanical properties of concrete, as well as the corrosion process induced by the chloride ion. The aim of this study was to investigate the effect of fly ash on the steel corrosion in concrete with various water-to-binder ratios. The corrosion process of steel bars embedded in concrete without fly ash and with 20% fly ash was tested under complete immersion, in 3.5 wt.% NaCl solution. Monitoring of open-circuit potential and linear polarization method and electrochemical impedance spectroscopy(EIS) were used to follow the corrosion process. Also, ASTM C1202 test method was used to estimate the concrete's resistivity of chloride penetration in concrete. The results obtained from electrochemical tests show that the use of fly ash has led to the improvement of corrosion resistance. Partial cement replacement by fly ash caused significant pore refinement, reduced permeability to chloride ions, and increased corrosion resistance.

제조합 대장균에서 과발현된 Citrobacter freundii KCTC2006 유래의 β-Tyrosinase를 이용한 3,4-Dihydroxyphenyl-L-alanine의 생산

이승구,노현수,홍승표,이규종,왕지원,태동년,엄기남,방상구,김영준,성문희 한국미생물생명공학회 ( 구 한국산업미생물학회 ) 1996 한국미생물·생명공학회지 Vol.24 No.1

재조합 대장균에서 대량발현 시킨 Citrobacter freundii KCTC 2006 유래이 효소 β-tyrosinase를 이용하여 pyrocatechol, sodium pyruvate, ammonium acetate로부터 3,4-dihydroxy phenyl-L-alanine을 생산하기 위한 연구를 수행하였다. 이 효소반응에 적합한 온도 및 pH 조건은 각각 18℃와 8.5로 결정되었고, 반응액 중의 ammonium acetate와 sodium pyruvate의 농도는 각각 300 mM, 50 mM 이상으로 조절하는 것이 적합하였다. Pyrocatechol의 경우는 20 mM에서 가장 높은 반응성을 나타냈으나, 기질을 반복적으로 첨가하며 장시간 동안 효소반응을 수행하는 경우에는 pyrocatechol의 고갈을 피하기 위하여, 20 mM에서 50 mM 사이로 조절하였다. 한편, 반응액 중에 ethanol을 10% 첨가한 경우에는 반응속도가약 20% 증가하였다. 이상과 같은 효소반응특성에 기초하여 조제한 기질용액에 β-tyrosinase를 1 unit/㎖ 농도로 가하고, pyrocatechol과 pyruvate가 고갈되지 않도록 간헐적으로 첨가하면서 효소반응을 수행한 결과, 24시간 만에 85.2%의 수율로 31.6g/ℓ의 3,4-dihydroxyphenyl-L-alanine를 생산할 수 있었다. By using the β-tyrosinase of Citrobacter freundii KCTC2006, which was cloned and overexpressed in Escherichia coli, 3,4-dihydroxy phenyl-L-alanine (L-DOPA) was synthesized efficiently from pyrocatechol, sodium pyruvate, and ammonium acetate. Optimal temperature and pH for the reaction were determined to be about 18℃ and 8.5, respectively. The effects of substrate concentrations were also examined at different concentrations of ammonium acetate, sodium pyruvate, and pyrocatechol. Ammonium acetate and sodium pyruvate increased the reaction rate until the concentrations reached to 300 mM and 50 mM, respectively. Although pyrocatechol showed the optimal concentration at 20 mM, it was controlled between 20 mM and 50 mM to avoid the depletion of substrate during the enzymatic synthesis. Based on above results, a reaction medium for the production of L-DOPA was prepared and incubated with 1 unit/㎖ of β-tyrosinase. Pyrocatechol and sodium pyruvate was added to the reaction solution intermittently to avoid the substrate depletion during the enzymatic reaction. After 24 hour of reaction, 31.6 g/ℓ L-DOPA was accumulated in the reaction solution as soluble and precipitated ones and the conversion yield was about 85.2%.

유색미에 관한 연구 : Ⅲ. 유색미 유망계통에 대한 주요 생육 특성

김광수,최윤표,김선택,최현구,정종태,김보경,유지홍,이희봉 충남대학교 농업과학연구소 2007 농업과학연구 Vol.34 No.2

국내외 유색미 수집종을 돌연변이원에 의해 유기된 우수 계통과 수집종간 상호교배에 의해 선발된 CNU 20계통을 파종하여 얻어진 주요 작물학적 특성을 살펴보면 다음과 같다. 1. 간장은 유색 메벼인 CNU126 계통이 대조품종인 동진벼와 같이 가장 컸고 메성인 CNU 128계통에서 가장 작았다. 2. 주당 분얼수는 CNU3, CNU50. CNU56, CNU112 계통에서 가장 많았고 대조품종과 CNU 128 계통에서 10개 미만으로 가장 적게 나타났다. 3. 수장은 육성 계통 중 CNU88 계통에서 가장 길었으나 대조구보다 짧고, 육성계통 중에서는 CNU 126 계통이 가장 짧았다. 4. 주당 영화수는 대조구인 동진벼보다 CNU50 계통에서 2배 이상 많았고, CNU158 계통에서 가장 적게 나타났다. 5. 천립중은 CNU113 계통에서 30g이상으로 대조구와 같이 가장 무거웠고, CNU128 계통에서 20g으로 가장 적었다. 6. 주당 수량은 대조구의 26.6g에 비해 CNU50, CNU112 계통에서 두배정도 높았고, CNU128, CNU158, CNU200 계통에서 가장 낮게 타나났다. Aims of this study were carried out to develop the useful lines induced from mutation and pedigree breeding methods among the collected genetic resources from national and domestic areas. In this study, Stem height of CNU126 line and check among them were high, while CNU128 was lower than other lines. Spiklet length of CNU88 was longer, but that of CNU126 was shorter than check. Number of spiklets per plant of CNU50 among lines have twice time than check. 1,000 grains weight of CNU113 was higher than check. In yield per plant, CNU50 and CNU112 were higher than check, Dongjinbyeo.

Effect of added mesophase pitch during the pitch synthesis reaction of PFO

Ji Hong Kim,Jong Gu Kim,Chul Wee Lee,Ki Bong Lee,Ji Sun Im 한국탄소학회 2017 Carbon Letters Vol.23 No.-

This research considers the effect of added mesophase pitch (MP) as an additive during the pitch synthesis reaction of pyrolyzed fuel oil (PFO). Two effects are generated by adding MP. One is an enhancement of thermal stability due to the high thermal property of the additive; the other is that the volatile compounds that were removed by vaporization of PFO during the thermal reaction can participate in the pitch synthesis reaction (PFO→pitch) more efficiently. The effect differs according to the amount of the additive. When the amount of the additive is less than 7 wt%, the first effect is dominant, whereas the second effect is dominant when the additive amount exceeds 10 wt%.