• 한국수자원학회논문집
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• 제38권3호
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• pp.213-222
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• 2005

이 연구에서는 다양한 강우조건에 따른 도시유출모형, SWMM의 매개변수들이 계산 결과치에 주는 민감도를 분석하였으며 이를 위해 3개 배수구역에 대하여 모형을 적용하였다. 첨두 유출량에 대한 민감도는 $S_Q$ (=1.0-(첨두유출량의 최소값($Q_{p,min}$)/첨두유출량의 최대값($Q_{p,max}$)))로 나타내었으며 강우 조건으로서는 강우규모, 강우지속시간, 강우분포 등의 3가지를 채택하였다. 강우조건의 변화에 따라 전반적으로는 불투수면적비, 관로경사, 초기침투능 등이 계산 결과치에 주는 민감도가 큰 것으로 분석되었다. 강우규모의 증가에 따라 관로경사 및 조도계수에 의한 영향이 증가되었고, 강우규모가 작아질수록 지표면 유출관련 매개변수가 민감하였다. 한편, 강우지속시간의 증가에 따라 대부분의 지표면 유출 및 관거흐름에 대한 매개변수들의 민감도가 둔감해지는 경향을 보였다. 강우분포에 대하여서는 Huff 1분위에서는 불투수면적비가 가장 민감하였으며 4분위에서는 관거흐름과 관련된 매개변수들이 민감하였다. 이러한 경향은 유효우량의 계산과 지표 및 관거흐름에 대한 운동파 해석과정에 기인하는 것으로 설명될 수 있다.

• 한국지구과학회지
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• 제31권7호
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• pp.708-719
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• 2010

한반도 서남해안의 고창군 동호 포켓형 대조차 해빈에서 계절에 따른 퇴적물 조직과 퇴적 환경 변화를 연구하였다. 표층 퇴적물은 3개 측선의 45지점(각 측선 당 15개 지점)에서 4계절(2006년 5월-2007년 2월) 동안 각각 채취하였다. 동호 해빈의 표층 퇴적물은 세립사, 중립사, 조립사로 대부분 구성되어 있으며, 함량비는 세립사가 가장 크다. 평균 입도는 여름에 가장 조립하게 나타난다. 표층 퇴적물의 공간분포는 봄, 가을, 겨울의 세 계절에 세립사와 중립사가 해안선과 평행한 띠 모양으로 나타나는 반면, 여름에는 중립사가 연구지역의 북쪽 부분에 우세하게 나타난다. 여름 동호 해빈의 표층 퇴적물에 미치는 영향은 조석이 파랑보다 효과적인 것으로 추정된다.

• 한국환경보건학회지
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• 제24권1호
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• pp.32-37
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• 1998

The Carbon Dioxide is the gas, which causes green house effects, unusual changes in the weather, destruction of the life. Almost every nation in the world is trying to search the countermeasure to this poisonous gas. I synthesized $Fe_3O_4$ and NaOH, in order to decompose the Carbon Dioxide. Among the particles synthesizing $Fe_3O_4$, I chose the equivalent ratio 1.00 which can decompose the Carbon Dioxide best, and fixed that equivalent ratio and added the 0.005-3.00 mole percentage of NiCl$_2$ and synthesized $Fe_3O_4$. I studied the decomposition of the Carbon Dioxide and methanized reaction, by measuring its crystal structure, thermochemistrical character and specific surface area. In decomposing the Carbon Dioxide, I used oxygen-deficit Magnetite which I produced by injecting the hydrogen gas into the synthesized sample. I observed the methanization reaction by raising the temperature of sample up to 650$\circ$C and having it reacted with the hydrogen gas. The decomposition of the Carbon Dioxide was added 0.005, 0.03, 0.05 mole percentage of NiCl$_2$ was more effective than pure $Fe_3O_4$. All sample in which the decomposition of the Carbon Dioxide took place produced the methane gas.

• 한국구조물진단유지관리공학회 논문집
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• 제13권2호통권54호
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• pp.206-214
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• 2009

FRP는 재료가 가지고 있는 특성 때문에 최근 들어 미국, 일본 등에서 보강 재료로 널리 쓰이고 있으며 우리나라에서도 활발한 연구가 이루어지고 있다. 본 연구에서는 EBR, NSMR 보강공법을 사용하는 동시에 AFRP의 종류와 보강면적을 다르게 보강하여 각 실험체의 거동과 연성을 평가하였다. 보강면적을 증가시킨 경우가장 큰 하중증가를 보였으나 취성적인 파괴 양상을 띠었으며 미성숙파괴가 일어났다. 공법면에서는 NSMR공법으로 보강하는 것이 더 효율적인 것으로 나타났으며 보강재료 표면의 요철이 연성파괴를 유도하는 것으로 나타났다.

• Ecology and Resilient Infrastructure
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• 제3권2호
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• pp.100-109
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• 2016

도시 지역의 물순환 구축과 비점오염물질 저감을 위해 구축되는 LID 시설의 지속적 효율은 주요 내부 구성요소(식물, 토양, 여재, 미생물 등)의 최적화된 상호작용에 의하여 나타난다. 본 연구는 식생이 조성된 4가지 LID 기술 (식생체류지, 소규모 인공습지, 빗물정원 및 나무여과상자)의 실제 도시 강우유출수의 유입으로 인한 식물의 성장상태 변화와 물순환 효과 및 비점오염물질 저감능력을 평가하기 위하여 수행되었다. 도시지역의 강우유출수의 약 40% 이상의 유출저감을 위한 적정 SA/CA (facility surface area / catchment area) 비는 시설마다 차이는 있지만 1~5% 범위가 적당한 것으로 평가되었다. 강우시 LID 시설에서의 유출저감은 비점오염물질 저감효율 향상에 중요한 영향을 끼치는 기작으로 나타났으며, SA/CA는 LID 시설의 중요한 설계인자로 도출되었다. 유출저감에 효과적인 시설은 빗물정원 > 나무여과상자 > 식생체류지 > 소규모 인공습지 순으로 나타났으며 입자상 물질 (TSS)의 제거능력은 빗물정원 > 나무여과상자 > 소규모 인공습지 > 식생체류지 순으로 분석되었다. 유기물 (COD, TOC), 영양물질 (TN, TP) 및 중금속 (Cu, Pb, Cd, Zn) 제거에는 빗물정원 > 나무여과상자 > 식생체류지 > 소규모 인공습지 순으로 조사되었으며 이러한 결과들은 향후 도시지역의 물순환 구축 및 비점오염물 제거에 적용되는 LID 시설의 설계에 중요한 자료로 활용 가능할 것으로 판단된다.

• 대한방사선치료학회지
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• 제14권1호
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• pp.175-186
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• 2002

The purpose of this study is directly measure and evaluate about absorbed dose change according to nominal energy and electron cone or medical accelerator on isodose curve, percentage depth dose, contaminated X-ray, inhomogeneous tissue, oblique surface and irradiation on intracavitary that electron beam with high energy distributed in tissue, and it settled standard data of hish energy electron beam treatment, and offer to exactly data for new dote distribution modeling study based on experimental resuls and theory. Electron beam with hish energy of $6{\sim}20$ MeV is used that generated from medical linear accelerator (Clinac 2100C/D, Varian) for the experiment, andwater phantom and Farmer chamber md Markus chamber und for absorbe d dose measurement of electron beam, and standard absorbed dose is calculated by standard measurements of International Atomic Energy Agency(IAEA) TRS 277. Dose analyzer (700i dose distribution analyzer, Wellhofer), film (X-OmatV, Kodak), external cone, intracavitary cone, cork, animal compact bone and air were used for don distribution measurement. As the results of absorbed dose ratio increased while irradiation field was increased, it appeared maximum at some irradiation field size and decreased though irradiation field size was more increased, and it decreased greatly while energy of electron beam was increased, and scattered dose on wall of electron cone was the cause. In percentage depth dose curve of electron beam, Effective depth dose(R80) for nominal energy of 6, 9, 12, 16 and 20 MeV are 1.85, 2.93, 4.07, 5.37 and 6.53 cm respectively, which seems to be one third of electron beam energy (MeV). Contaminated X-ray was generated from interaction between electron beam with high energy and material, and it was about $0.3{\sim}2.3\%$ of maximum dose and increased with increasing energy. Change of depth dose ratio of electron beam was compared with theory by Monte Carlo simulation, and calculation and measured value by Pencil beam model reciprocally, and percentage depth dose and measured value by Pencil beam were agreed almost, however, there were a little lack on build up area and error increased in pendulum and multi treatment since there was no contaminated X-ray part. Percentage depth dose calculated by Monte Carlo simulation appeared to be less from all part except maximum dose area from the curve. The change of percentage depth dose by inhomogeneous tissue, maximum range after penetration the 1 cm bone was moved 1 cm toward to surface then polystyrene phantom. In case of 1 cm and 2 cm cork, it was moved 0.5 cm and 1 cm toward to depth, respectively. In case of air, practical range was extended toward depth without energy loss. Irradiation on intracavitary is using straight and beveled type cones of 2.5, 3.0, 3.5 $cm{\phi}$, and maximum and effective $80\%$ dose depth increases while electron beam energy and size of electron cone increase. In case of contaminated X-ray, as the energy increase, straight type cones were more highly appeared then beveled type. The output factor of intracavitary small field electron cone was $15{\sim}86\%$ of standard external electron cone($15{\times}15cm^2$) and straight type was slightly higher then beveled type.

• Journal of Magnetics
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• 제7권3호
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• pp.63-71
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• 2002

Three fabrication techniques for forming thin barrier layer with uniform thickness and large barrier height in magnetic tunnel junction (MTJ) are discussed. First, the effect of immiscible element addition to Cu layer, a high conducting layer generally placed under the MTJ, is investigated in order to reduce the surface roughness of the bottom ferromagnetic layer, on which the barrier is formed. The Ag addition to the Cu layer successfully realizes the smooth surface of the ferromagnetic layer because of the suppression of the grain growth of Cu. Second, a new plasma source, characterized as low electron energy of 1 eV and high density of $10^{12}$ $cm^{-3}$, is introduced to the Al oxidation process in MTJ fabrication in order to reduce damages to the barrier layer by the ion-bombardment. The magnetotransport properties of the MTJs are investigated as a function of the annealing temperature. As a peculiar feature, the monotonous decrease of resistance area product (RA) is observed with increasing the annealing temperature. The decrease of the RA is due to the decrease of the effective barrier width. Third, the influence of the mixed inert gas species for plasma oxidization process of metallic Al layer on the tunnel magnetoresistance (TMR) was investigated. By the use of Kr-O$_2$ plasma for Al oxidation process, a 58.8 % of MR ratio was obtained at room temperature after annealing the junction at $300{^{\circ}C}$, while the achieved TMR ratio of the MTJ fabricated with usual Ar-$0_2$ plasma remained 48.4%. A faster oxidization rate of the Al layer by using Kr-O$_2$ plasma is a possible cause to prevent the over oxidization of Al layer and to realize a large magnetoresistance.

• 한국농공학회논문집
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• 제60권5호
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• pp.105-113
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• 2018

In this study physical and chemical characteristics of rice straw ash (RSA) were analyzed in agricultural by-products such as the characteristics of soil pH, electric conductivity (EC), total phosphorus (T-P), available phosphate (Avail-P), and cation exchange capacity (CEC). The results showed that RSA is of mainly C in 95.74% and followed by Si > Al > P > Mg > K > Ca. The pH of RSA was high near 11 and the T-P concentration was $2,322.38{\pm}10.35mg/kg$. The specific surface area of RSA was $123.50m^2/g$, which was much lower than that of biochar. The X-ray diffraction (XRD) analysis indicated that RSA were C and Si based crystalline. TCLP and KSLT test results implied that the heavy metal concentrations were below the environmental standards and would not impose the risks. T-P concentration increased from $225.59{\pm}12.69mg/kg$ to $593.39{\pm}17.36mg/kg$ along with RSA mixing ratio to soil from 0% to 15%. Both pH and EC values were increased with the increase of RSA ratio. The changes in Avail-P and CEC were not when RSA mixing ratio was 1%. whereas the Avail-P concentration was slightly increase when the mixing ratio was more than 5%. Additional investigation considering receiving soil characteristics based on the results of this study would help effective application of RSA to soil.

• 한국미생물·생명공학회지
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• 제7권3호
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• pp.165-173
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• 1979

자연선조사한 대장균B주의 세포분열회복활성분을 구명코저 자외선내성균인 대장균 B/r 주의 초음파추출액으로부터 활성성분分을 분리한 결과 $\beta$-NAD가 관여함이 발표되었다. 본고에서는$\beta$-NAD 이외 Magnesium이 활성물질의 안정화가 중요한 역할을 나타냄을 구명하였으며 10~30%의 서당밀 도구배원심분리에 의해 2 개의 새로운 활성부분이 있음을 확인하였다. 2 개의 활성물질 가운데 하나는 원심관의 최하부에 위치하였으며 또 다른 하나는 상부의 분자량 45,000 부위에서 회수되었다. 하부에 위치한 활성획분은 Mg++이 그 활성에 무관하였으나 상부의 저분자 활성부분은 $Mg^{++}$을 첨가하지 않으면 회수가 불가능하였다. 저분자활성부분은 pronase에 대해 감수성이었으며 DNA-ligase 는 아님이 추정되었다. 초원심분리과정에 $N_2$ gas를 처리할 경우 aeration에 비해 약 2 배의 활성이 나타났다. $Mg^{++}$은 $\beta$-NAD에 또하나의 회복활성 및 필수적인자로 요구된다고 생각된다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2001년도 The 6th International Symposium of East Asian Resources Recycling Technology
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• pp.240-244
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• 2001

Recycling process involving mechanical, thermal, hydrometallurgical, and sol-gel step has been applied to recover cobalt and lithium from spent lithium ion batteries and to synthesize LiCoO$_2$from leach liquor as cathodic active materials. Electrode materials containing lithium and cobalt could be concentrated with 2-step thermal and mechanical treatment. Leaching behaviors of the lithium and cobalt in nitric acid media was investigated in terms of reaction variables. Hydrogen peroxide in 1 M HNO$_3$solution turned out to be an effective reducing agent by enhancing the leaching efficiency. O f many possible processes to produce LiCoO$_2$, the amorphous citrate precursor process (ACP) has been applied to synthesize powders with a large specific surface area and an exact stoichiometry. After leaching used LiCoO$_2$with nitric acid, the molar ratio of Li/Co in the leach liquor was adjusted at 1.1 by adding a fresh LiNO$_3$solution. Then, 1 M citric acid solution at a 100% stoichiometry was also added to prepare a gelatinous precursor. When the precursor was calcined at 95$0^{\circ}C$ for 24 hr, purely crystalline LiCoO$_2$was successfully obtained. The particle size and specific surface area of the resulting crystalline powders were 20 пm and 30 $\textrm{cm}^2$/g, respectively The LiCoO$_2$powder was proved to have good characteristics as cathode active materials in charge/discharge capacity and cyclic performance.