• Polymer(Korea)
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• v.32 no.6
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• pp.566-572
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• 2008

Polyethylene has been prepared via metallocene catalysts [(TMDS)$Cp_2$]$ZrCl_2$, 1, and [$(n-Bu)_2Cp_2$]$ZrCl_2$, 2, in the presence of hydrogen as a chain transfer reagent. Increase of hydrogen flow to the polymerization reactor resulted in the drop of catalytic activity, reduction of molecular weight of polyethylene, getting narrow of molecular weight distribution of polyethylene, and melting point of the polyethylene wax. It should be noticed that it was possible to control molecular weight down to 1500 and melting temperature to 60 $^\circ$C of polyethylene wax using the catalyst 1 that has been developed by authors as well as the catalyst 2 from Exxon.

• Proceedings of the Korea Water Resources Association Conference
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• 2023.05a
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• pp.64-64
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• 2023

황강댐은 임진강 상류 군사분계선으로부터 약 42km떨어진 위치에 존재하며 약 3~4억톤의 규모로 추정된다. 이에 우리나라는 약 7천만톤 규모의 군남홍수조절지를 건설하여 임진강 상류로부터 기인하는 홍수를 방어하고 황강댐의 무단방류에 대비하고 있다. 과거 2009년 9월 6일 임진강 상류 황강댐에서의 대규모 방류로 인해 경기도 연천군 일대에 홍수가 발생하여 이로 인한 인명 및 재산피해가 발생한 바 있으며, 2020년 8월 5일에는 장마전선으로 인한 폭우와 더불어 임진강 필승교 수위관측소의 수위가 급상승하면서 관측 이래 역대 최고수위가 발생하여 홍수경보가 발령되고 인근 주민이 대피하는 사례가 발생하였다. 또한, 2022년 6월 27일부터 발생한 장마전선 및 집중호우로 인해 임진강 필승교 수위관측소의 수위가 급상승하면서 홍수주의보가 발령되고 인근 주민이 대피하는 사례가 발생하였으며, 7월에는 비가 내리지 않는 상황에서 황강댐의 방류로 추정되는 유입량이 필승교 수위관측소와 군남홍수조절지에서 관측되었다. 이에 본 연구에서는 인공위성 영상에서 추출한 황강댐의 수위를 이용하여 수문모형과 저수지 운영 알고리즘을 구축하고 당시 발생한 홍수사례를 분석하여 황강댐의 운영방식을 추정하였다. 분석결과, 2020년 8월 5~7일 사이에 발생한 유입량의 경우 자체 유역 유입량은 전체 유입량대비 약 33%이나 북한 황강댐으로부터 추가로 방류된 양은 약 67%로 군남홍수조절지 유입량의 3/2 가량이 북한 황강댐의 방류량으로부터 발생된 것으로 보이며 2021년 6월에도 유사한 양상을 보였다. 하지만, 북한 황강댐의 운영방식이 용수공급을 위한 고수위 유지 운영방식에서 홍수기에 댐 월류 및 파괴를 방지하기 위한 사전방류를 수행하는 것으로 추정되었다.

• Journal of Nutrition and Health
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• v.51 no.3
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• pp.215-227
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• 2018

Purpose: This study was conducted to verify the effects of increases in consuming Korean food in patients who underwent cardiovascular disease (CVD) surgery based on a Korean diet control education program and to investigate the effects of Korean diet control nutrition education on risk factors of CVD, changes in amounts of medication, and nutritional intakes. Methods: The subjects consisted of 15 patients who have undergone CVD surgery within three years and continuously taken cardiovascular drugs. The Korean traditional diet (KTD) emphasizes intake of vegetables and fermented foods to lower saturated fat and cholesterol intake. We applied a KTD education program that included a modified DASH (The dietary approaches to stop hypertension) diet for cardiovascular disease patients. Korean diet control education was then applied to the patients for 12 weeks to evaluate the risk factors of CVD and the state of nutritional intakes. Results: The Korean diet control compliance score increased significantly (p < 0.001) as Korean diet control education was implemented. Additionally, the obesity indexes, waist circumference (WC) (p = 0.002) and waist-to-hip ratio (WHR) decreased significantly (p < 0.001) after subjects received the education. Moreover, the glycemic control index, HbA1c, was significantly decreased (p < 0.05) from $7.3{\pm}1.0%$ before the education to $7.0{\pm}1.1%$ after the education. Changes in the amounts of Korean diet intake consisted of significant increases in cooked rice with whole grains, narmuls (vegetables either raw or cooked), kimchi, and traditional fermented foods following the education. Moreover, the nutritional intake after the education showed significant decreases (p < 0.05) in animal protein, animal lipids, and cholesterol. However, the intakes of Na, K, dietary fiber, vitamin A, vitamin $B_6$, vitamin C, and folic acid were significantly increased. Conclusion: The active encouragement of consuming Korean food and the intervention of implementing diet control education positively affected nutritional intake, the obesity index and glycemic control of patients who have undergone CVD surgery.

• Korean Journal of Human Ecology
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• v.17 no.3
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• pp.511-519
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• 2008

The purpose is to investigate the factors moderating the relationships between food choice motives such as health concern, weight control and ethical concern, and vegetable intake. Data were collected from adult people(N=290) in Jeonnam Province for finding the correlation of the food choice motives and the moderated variables as food involvement and food neophobia with vegetable intake. Moderated regression analysis was used to analyse the survey data. The results indicates that the moderated variables of food involvement and food neophobia significantly affect vegetable intake. However, the food choice motives of health concern, weight control, ethical concern do not have significant effects on vegetable intake. The findings can help adult people prefer healthy eating.

• Proceedings of the Korean Society for Bio-Environment Control Conference
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• 2000.10b
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• pp.120-123
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• 2000

느타리버섯의 재배 환경관리는 버섯의 품질과 수확량을 좌우하는 매우 중요한 요소이지만 버섯배지의 적정 수분유지 및 습도조절에는 많은 노력과 시간이 요구된다. 이 연구는 느타리버섯의 수확시기에 버섯재배사 통로를 왕복 주행하며 버섯균상 2열 4-5단 균상에 필요한 량의 물을 뿌려주고 바람으로 배지표면의 물을 말려주며 주기적으로 안개분무로 가습하여 버섯 재배환경을 적합하게 유지하는 장치개발을 위하여 수행하였다. (중략)

• Proceedings of the Korea Water Resources Association Conference
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• 2012.05a
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• pp.393-397
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• 2012

인접한 저수지 간의 연계운영을 통한 홍수조절 및 용수공급능력을 제고시키기 위해서 저수용한 공유기법의 일환인 병렬저수지 시스템을 연구대상으로 안동댐 및 임하댐 유역을 연계운영기법으로서 홍수조절능력을 제고시키고 안동댐의 저수량을 확보시켜 용수공급능력을 제고시킬 수 있는 방법을 연구하였다. 특히 유역추적과 하도추적을 통해 계산된 매개변수들을 실제 형태와 비교분석하여 산정하고, 이에 따른 가장 적합한 강우-유출해석을 통한 하류 지역의 홍수 피해를 최소화하기 위한 예 경보 기법을 제시하였다. 최적의 유수전환용량을 산정하기 위해 저수지간의 Swiching 기법을 고려하였으며, HEC-HMS 모형을 이용하여 재현기간별 유입량을 예측하여 결과를 도출하였다.

• Proceedings of the Korea Information Processing Society Conference
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• 2012.11a
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• pp.1252-1255
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• 2012

CRDI 디젤엔진을 산업용 엔진에 적용하여 최근 강화된 국내외의 배출가스 규제 조건을 충족시키기 위해 사용자가 연료의 분사시기와 분사량을 조절할 수 있는 CRDI ECU 제어 알고리즘을 개발하였다. CRDI 엔진 제어 ECU의 입력 요소 중 CKP와 CMP 센서를 이용하여 디젤 노킹 및 롱투스를 판별하는 알고리즘을 개발하여 분사시기와 분사량의 조절 시점을 결정하고, 엔진의 이상 유무를 판별할 수 있는 알고리즘을 개발하여 엔진의 밸런스를 조절함으로써 연비 향상 및 유해가스 저감을 효율적으로 개선할 수 있도록 하였다.

• Journal of Korean Ophthalmic Optics Society
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• v.20 no.3
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• pp.341-347
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• 2015

Purpose : This study was to examine a correlation of response AC/A ratio by additional spherical powers with PD(Pupilary distance) and relative accommodation, and was to investigate correlation of CA/C ratio by prism powers. The mean differences between a reciprocal response AC/A ratio and a CA/C ratio were compared, and were suggested to be used as data in the refractive power and prism prescriptions in the clinical. Methods: The open field autorefractometer (Nvision-K 5001, Shin nippon) and Howell target at 40 cm fixation distance to 62 persons with average $22.62{\pm}2.84$ ages were used to measure the response AC/A ratio according to additional Spherical powers. The CA/C ratios were measured using the DOG card at 40cm according to prism powers. Results: When the response accommodation according to Additional Spherical power changes and the response accommodation according to prism power changes were compared, it was larger than the response accommodation according prism power change. These were significant differences statistically. The correlation of response AC/A ratio and PD is showed as r = -0.158, the CA / C ratio is shown as r = 0.093. The correlation of response AC/A ratio and relative accommodation showed as r = -0.253, the CA/C ratio showed as r = 0.566 that is predictable correlation. The correlation of response AC/A ratio and CA/C ratio showed as r = -0.355 that is low minus correlation (p = 0.000). The difference between a reciprocal response AC/A ratio and a CA/C ratio showed $0.12{\pm}0.06D/{\Delta}$ with a significant difference statistically (p=0.000). Conclusions: The correlation of relative accommodation and CA/C ratio showed that depend on the individual, The more a relative accommodation is, the higher a response accommodation of convergence by convergence stimulus is. The reciprocal response AC/A and CA/C ratio showed significant differences statistically. This can have higher CA/C ratio in patients with low AC/A ratio in clinical as an independent variable. Thus when the abnormal binocular vision was prescribed in the clinical, it is necessary to consider the accommodative response even if the AC/A ratio is a normal range.

• Journal of Korea Water Resources Association
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• v.40 no.5
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• pp.383-396
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• 2007

The studies on efficiency of flood control reservoir has been introduced into four categories including direct flood control contribution by reservoir, flow-duration change and environmental-ecological change in downstream of dam and flood damage estimation of flood plain. In spite of all the previous approaches, the quantification of the effect of reservoir on the flood control in planning stage is quite complex due to lack of a standard for quantifying feasibility of project. In this study, we develop a methodology that can clearly and accurately quantify the flood damage reduction together with the existing flood level reduction at downstream. The proposed approach uses three appraisal standards of flood control: 'potential safety', 'relative risk' and 'absolute risk' according to the risk by stage. The developed methodology was applied to the Namhan river basin with the storm event of July, 2006. The result shows the damage reduction of 4,189 billion won was estimated. The economic benefits for the flood control effect by dam will greatly contribute to the public understanding of the importance and the effect of the flood control by dam.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2006.11a
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• pp.203-206
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• 2006

We have studied, for maximizing the total impulse of liquid propulsion system, Propellant Utilization System (PUS) to minimize outage of propellant. Propellant outage is mainly influenced by propellant mixture ratio during flight and real quantity of loaded propellant. If one employs cryogenic propellant, the variation of propellant density due to the temperature change has major effect on outage control. Feedback control of propellant level of each tank during flight could deplete both tanks simultaneously. To introduce this system, however, the mixture ratio control system of rocket engine is necessary.