적산온도법에 의한 에폭시 모르터의 초기강도 예측에 관한 연구

연규석,大濱嘉彦,이윤수,김철영 강원대학교 부설 석재복합신소재 제품연구센터 1999 석재연 논문집 Vol.4 No.-

에폭시 모르터를 보수용으로 사용할 경우 거푸집의 회전율을 높이고 완전한 시공관리 차원에서 초기강도의 예측은 매우 중요하다 할 수 있다. 이에 본 연구는 결합재로서 에폭시 수지를 사용한 폴리머 모르터를 제조하고 경화제의 첨가량에 따른 초기강도의 변화를 시멘트 콘크리트에 적용되어 온 적산온도 방법에 의해 예측하는데 목적이 있다. 에폭시 모르터 제조에 사용된 재료는 반응성 희석제로 변성한 저점도형 Bisphenol-A계 액상 에폭시를 사용하였으며, 경화제는 지방족 Amine 변성 경화제를 사용하였다. 실험결과 에폭시 모르터의 기준온도는 -3∼-11℃로 나타났고, 경화제 첨가량에 따른 적산온도와 압축강도 사이의 강도 추정식은 다음과 같이 구할 수 있었다. 30% : Y = 292.42 Ln(M) - 881.16 40% : Y = 386.64 LN(M) - 1223.1 50% : Y = 273.18 LN(M) - 1040.5 Epoxy mortar is widely used to repair cement concrete structure and predicting strength of the mortar is of importance in its application. The objectives of this study were to compare the development of compressive strength of epoxy mortar with respect to maturity and to propose a predictive model for strength development of epoxy mortar. A series of tests were carried out for the hardener contents of 30, 40 and 50 percentage of resin and compressive strengths were measured at the age of 6, 12, 24, 72, 120 and 168 hours respectively under the cure temperature of 0, 10, 20 and 30℃. The datum temperature was estimated by measured strength, and the maturity was calculated with the estimated datum temperature. It was shown that the compressive strength of epoxy mortar could be predicted by regression analysis from the maturity-compressive strength relationship.

정신분열증 환자의 혈청내 Haloperidol과 Prolactin 함량에 관한 연구

연병길,한규희,양병환,김철규,전남호 漢陽大學校 精神健康硏究 1985 精神健康硏究 Vol.3 No.-

폴리머 모르터의 난연성 개선에 관한 연구

연규석,大濱嘉彦,김남길,김철영,지경용 강원대학교 부설 석재복합신소재 제품연구센터 2000 석재연 논문집 Vol.5 No.-

불포화 에스트테르 수지의 큰 이용분야의 하나로 건축재료가 있으나 여기서 가장 문제로 되어 있는 것이 바로 난연성의 향상이다 불포화 폴리에스터수지는 탄소를 구성성분으로 하는 유기물이므로 무기재료와 같은 불연성을 기대하기는 어려우나 어느 정도까지는 연소를 억제시킬 수는 있다. 본 연구에서는 UP를 결합재로 하고 탄산칼슘을 충진재로, 규사를 잔골재로 하는 폴리머 모르터를 제조하고 이에 첨가되는 난연제량과 UP량을 각각, 5~12.5%, 12~24%로 변화시켜 난수별 난연특성을 고찰하였던 바, UP사용량에 따른 특정 난연제의 최적 사용량 범위를 얻을 수 있었다. One of the fields using the unsaturated polyester resin is the constructional material, but the most serious problem, in this field, is the incombustibility improvement. it is hard to expect the noncombustibility as in the inorganic materials for the unsaturated polyester resin since whose structural material is carbon, but the combustion can be controlled up to some degree. In this study the polymer mortars were made in which the unsaturated polyester resin as binder, the calcium carbonate as filler and the silica sand as fine aggregate. The incombustible characteristics were then investigated as varying the amount of the flame retarder and the unsaturated polyester resin from 5 to 12.5% and 12 to 24%, respectively. Based on the results, the optimized range of amount of flame retarder used with various amount of unsaturated polyester resin could be obtained.

철원산 현무암을 이용한 폴리머 콘크리트의 물리·역학적 특성

연규석,이윤수,김철영 강원대학교 부설 석재복합신소재 제품연구센터 1999 석재연 논문집 Vol.4 No.-

이 연구는 철원지역에 분포하는 현무암을 대상으로 부가가치를 향상시킬 수 있는 상품을 개발하기 위한 기초자료를 얻기 위하여 현무암에 대한 암석학적 및 물리적. 화학적 특성을 규명하고자 하였다. 철원지역의 현무암은 크게 대다공상 조직과 소다공상 조직을 갖는 2가지 암상으로 구분할 수 있으며, 주로 사장석과 휘석류, 감람석, 불투명 광물 등으로 구성되어 있고, 일부 기공속에서는 석영과 방해석이 발견된다. 현무암의 비중(참비중)은 2.89∼2.94, 공극률과 흡수율은 각각 9.96∼13.7%, 4.01∼6.53% 값의 범위를 보였고, 마모감량은 24.7∼30.5wt.%, 일축 압축강도와 인장강도는 각각 536∼875㎏f/㎠, 53.7∼69.1㎏f/㎠의 값이므로, 강도의 경우 기공이 적은 현무암이 많은 현무암보다 약간 더 강한 것으로 나타났다. 현무암의 미량원소 함량중 Co, Cr, Ni 등의 함량은 KIoke(1979)가 제시한 농작물에 독성을 줄 수 있는 토양중의 최대 허용한계값 (Co 50 ppm, Cr 100 ppm, Ni 100 ppm) 보다 더 높은 값을 보여, 철원현무암을 석제품으로 가공할 때 생기는 미석분을 처리할 때에는 이러한 점을 충분히 고려하는 것이 바람직할 것이며, 현무암의 분말시료에 대한 양이온 교환 용량 값에 의하면 대다공상 현무암 (5.81meq/100g)의 경우 중금속 흡착제로 활용할 수 있는 가능성이 충분히 있어, 이에 대한 차후의 면밀한 연구가 필요할 것으로 판단된다. Feasibility of chulwon basalt as a coarse aggregate for polymer concrete was investigate to solve the environmental problems associated with the waste. Basalt aggregates were prepared and used to produce basalt polymer concrete. The concrete was tested for physical and mechanical properties. The tested properties of basalt polymer concrete were not different from those of normal polymer concrete. It was concluded that chulwon basalt could be used as an aggregate for polymer concrete production. However, the long-term behavior, thermal extension and durability of basalt polymer concrete were suggested to be further explored.

혈액 내 구리, 아연 및 ceruloplasmin 농도에 흡연, 음주 및 신체적 활동이 미치는 영향

홍연표,강은용,신인철,최병선,박정덕,장임원,박진완 大韓産業醫學會 1999 대한직업환경의학회지 Vol.11 No.4

Objectives : To investigate the influence of smoking, alcohol ingestion, and physical activity on copper and zinc in RBC and serum and serum ceruloplasmin, this study was performed in a cross-sectional study in 113 healthy men aged 20 to 40 years who had no symptomatic liver, heart, gastrointestinal, and other chronic diseases. Methods : At the men's entry into the study, blood samples were drawn from each subject and immediately centrifuged for analysis of copper, zinc, iron, ceruloplasmin, total cholesterol, and hematocrit. Each man completed a questionnaire that provided information on smoking, amount of alcohol intake, and physical activity. Partial regression analysis was performed on confounding variables such as age, body mass index, hematocrit, serum cholesterol, and serum iron. Results : In general linear models, adjustment for confounding variables did not show statistical differences, and there was only an increasing tendency in serum copper in heavy smoker(P=0.0678). There was no difference between high physical activity with mild smokers and lower physical with heavy smokers. Conclusions : This study suggested that copper, zinc and ceruloplasmin were not good biomarker for early effect by smoking, alcohol intake and physical activity in young adult. However, selection bias should be considered in evaluation of this result, and a large prospective study will be needed in advance on usefulness of copper, zinc and ceruloplasmin as a marker for risk factors and early change of atherosclerosis.

574(H) X 489(V)개의 화소를 가지는 CCD형 촬영소자

허연철,이종덕 경북대학교 센서기술연구소 1990 센서技術學術大會論文集 Vol.1 No.1

수평으로 574개, 수직으로 489개의 화소를 가지는 1/2인치 CCD형 촬영 소자를 설계하고 제작하였다. 오버플로우 드레인의 동작을 이해하고 이를 효과적으로 이용한 설계를 위하여 광다이오드의 수직방향 전위분포를 계산하였고 전위분포의 간접적 검증 방법으로 펀치쓰루 전류를 측정하여 펀치쓰루가 일어나기 시작하는 바이어스 조건을 얻어서 계산치와 비교하는 방법을 사용하였다. BCCD의 최대 전위와 최대 신호 저장 용량을 BC MOSFET를 이용하여 측정된 전류로부터 계산하여 암신호와 구동 클락의 효율성을 고려할 때 전달단 구동 클락의 전압과 전달단의 크기가 타당하다는 결론을 얻었다. 출력단으로 쓰이는 이단 소스 플로워의 주파수 특성을 측정하고 SPICE를 이용한 모의 실험도 병행하여 30만 화소 정도의 촬영 소자에는 사용가능하나 더 높은 해상도를 가지는 촬영 소자에서는 고주파에서 이득이 작아지기 때문에 적용상에 어려움이 있음을 알았다. A 1/2-inch interline CCD image sensor with 574(H)X489(V) pixels has been designed and fabricated. The chip is compatible with the NTSC system. The vertical potential profile of a photodiode is calculated to analyze the VOFD action and the measurement of the punchthrough edge conditions is adopted as indirect verification of the profile. The maximum potential and the charge storage capability of BCCD are also calculated with the measured current from BCMOSFET and it is concluded that the storage capability and the voltage level of operation clock are reasonable in terms of the dark signal and the efficiency of clock pulse. The frequency response of the two stage source follower is also simulated by SPICE and measured for the investigation of the limit of the operation frequency. Its gain is sufficient for image sensor with about 300000 pixels. But it is not suitable for an image sensor with more than one million pixels since its gain is too small at the high frequency.

Hydrogen Peroxide 농도와 적용시간이 Hydroxyapatite discs의 미백과 물리적 성질에 미치는 영향

양연미,이두철,백병주,김재곤,신정근 대한소아치과학회 2007 大韓小兒齒科學會誌 Vol.34 No.1

법랑질의 주성분인 hydroxyapatite 분말을 성형하고 소결하여 착색을 유발한 다음 과산화수소의 농도와 적용 기간의 변화에 따라 나타나는 미세 조직과 기계적 성질의 변화 및 미백 효과 등에 관한 연구를 통해 다음과 같은 결론을 얻었다. 1. 과산화수소의 농도와 적용시간이 증가함에 따라 미백 효과가 증가되었다. 2. 표면조도는 15% 과산화수소 10일, 30% 과산화수소 7, 10일 적용 시 유의한 차이로 증가하였다(p<0.05). 3. X-선회절 분석결과 미백처리 전·후의 결정상의 변화는 관찰되지 않았으나, 주사전자현미경 관찰시 표면의 미세구조는 과산화수소 농도와 적용시간의 증가에 따라 미세기공이 증가하였다. 4. 2축 굽힘강도는 30%농도의 과산화수소로 7, 10일 적용하였을 때 유의한 차이로 감소되었다(p<0.05). 5. 미소 경도값은 15% 과산화수소 10일과 30% 과산화수소 3, 7, 10일 적용 후 유의한 차이로 감소되었다(p<0.05) The purpose of this study was to evaluate the effect that various concentration and application time of hydrogen peroxide had on tooth whitening and physical properties. The hydroxyapatite (HA) discs of 12 mm (Φ) x 1.2 mm (t) in dimensions were made by compression (100 kg/㎠) and sintering (at 1350℃ for 2 hours). All specimens were polished sequentially with #240 through #2000 emery paper and one side of each specimen was polished finally with 0.3 ㎛ alumina paste. The discs were placed in sterile whole stimulated saliva overnight at 37℃ in order to form an in vitro pellicle layer. Then the discs were rinsed with distilled water and soaked into staining broth at 37℃ for 7 days. These stained specimens were bleached with hydrogen peroxide according to the change of concentration (3∼30%) and application time (3∼10 days). The specimens were analyzed with a spectrophotometer, X-ray diffractometer (XRD), scanning electron microscope (SEM), surface roughness tester, microhardness tester and biaxial flexural strength. The results of present study can be summarized as follows: 1. The bleaching effect was increased with the increased concentration and the extended application time of hydrogen peroxide. 2. The surface roughness was significantly increased from the specimen bleached with 15% hydrogen peroxide for 10 days and with 30% for 7 and 10 days respectively (p<0.05). 3. The changes of crystal phase observed by XRD between before and after bleaching weren' t shown of any difference, but microporous structure of surface observed by SEM was shown of increase with the increased concentration and the extended application. 4. The biaxial flexural strength was significantly decreased from bleaching of specimen with 30% hydrogen peroxide for 7 and 10 days respectively (p<0.05). 5. Microhardness was significantly decreased from bleaching with 15% hydrogen peroxide for 10 days and with 30% for 3, 7 and 10 days respectively (p<0.05). Although the tooth bleaching effect was greater when the high concentration was applied, further in vivo experiment will be needed to prove it s safety.

24주간 추적하는 임상 연구에서 한국인 남자 알코올 의존 환자의 비재발률

강철중,김성곤,남궁기,조동환,이병욱,최인근,최용성,박성봉,제영묘,김현경,김성연 大韓神經精神醫學會 2006 신경정신의학 Vol.45 No.1

Objetives : In order to provide useful data tbr the further clinical studies with Korean alcohol-dependent patients, enrollment and non-relapse rates were investigated while alcohol-dependent patients wcre followed up for 24 weeks. Methods : The subjects of this study were alcohol-dependent male patients who, for the first time, visited a hospital among 3 groups of hospitals, University Hospital, General Hospital or Mental Hospital, or those who needed to be followed up after discharge from those hospitals. After assigning 12 subjects to each hospital, we investigated enrollment and non-relapse rates while cognitive-behavioral therapy and pharmacotherapy were provided. Results : 1) Forty-eight patients were enrolled and the rate of enrollment was 36.4%. The enrollment rate in the University Hospital group was 52.1%, in the General Hospital group 50.0%. and in the Mental Hospital group 10.4%. 2) In 48 patients, non-relapse rate was 27.1% at 12 week and 18.8% at 24 weeks after starting follow-up. It was 24.4% and 20.0% at 12 and 24 weeks, repectively, in the University Hospital group while the General Hospital group showed 33.3% and 16.7%, respectively, and the Mental Hospital Group showed 20.0% at both 12 and 24 weeks. Conclusion : These results provide important data for further clinical studies of Korean alcohol-dependent patients.

초고속인터넷 요금제의 개선 방향

신병철, 김연우 충북대학교 컴퓨터정보통신연구소 2011 컴퓨터정보통신연구 Vol.19 No.2

-본문참고-

참깨에 있어서 作畦方法이 生育, 收量構成要素, 收量 및 잎마름病 發生에 미치는 影響

李徹熙,朴然圭 충북대학교 농업과학기술연구소 1991 農業科學硏究 Vol.9 No.2

This experiment was conducted to study the effect of several ridging methods under vinyl mulching and vinyl exclusion at flowering period on growth, yield components, yield and occurrence of leaf blight caused by Corynespora cassiicola in sesame. The results obtained are summarized as follows ; 1.On vinyl mulching and ridging method of 75cm (40×13cm) plot, plant height, fresh weights of leaves, stem and root were increased. 2.On vinyl mulching and ridging method of wide ridge and row space, no. of total and fresh leaves were higher, and high fresh leaves ratio was maintained in maturation period. 3.Length of capsule setting, no. of total leaves and no. of matured capsule in vinyl mulching and ridging method of 75cm (40×13cm) was increased. 4.On vinyl mulching, grains of capsule per plant in high part of capsules was higher, and maturation ratio was increased 10-20% than vinyl exclusion plot, and on ridging method of narrow ridge and row space was increased than that of other. 5.There were significant positive correlations between yield of seed and other agronomic characteristics such as length of capsule setting(r=0.42*), fresh weight of leaves(r=0.45*), fresh weight of root(r=0.81**), and no. of matured capsules(r=0.47*). 6.Yield of seed on vinyl mulching plot was increased 8% (92kg/10a) than vinyl exclusion at flowering period, and on ridging method of 75cm(40×13cm) plot was increased 3% (92kg/10a) than conventional ridging method of 150cm(50×10cm). 7.On vinyl mulching and ridging method of 75cm(40×10cm), occurrence of Corynespora blight was reduced, and there were high significant negative correlations between occurrence of Corynespora blight and other agronomic characteristics such as fresh weight of leaves(r=-0.58**), fresh leaves ratio(r=-0.78**), no. of matured capsule(r=-0.58**), and yield of seed(r=-0.64*).