• 한국작물학회지
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• 제30권3호
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• pp.320-325
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• 1985

수도 일본형 12품종과 일인교잡종 9품종을 공시하여 쌀의 아밀로스 함량과 전분의 성질, 수분흡수속도, 밥의 단단함 등 물리적 성질과의 관계를 검토하였다. 1. 아밀로스 함량은 전분의 상대적 결정도, 수분흡수속도 및 밥알의 단단함과 아무런 상관을 보이지 않았으나 전분현탁액의 투광도와는 유의한 정상관(r =0.473＊)을, chalkiness와는 부상관(r=-0.544＊)을 그리고 알칼리 붕괴도와는 매우 유의한 정상관(r =0.631＊＊)을 보였다. 2. 전분의 상대적 결정도는 알칼리 붕괴도(r=-0.453＊) 및 수분흡수속도(r=-0.477＊)와 부상관을 보였고, 쌀알의 표면적은 알칼리 붕괴도(r=-0.726＊＊)및 수분흡수속도(r =-0.438＊)와 높은 부의 상관을 나타냈다.

• 한국토양비료학회지
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• 제20권1호
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• pp.69-76
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• 1987

The aerobic heterotrophic bacteria in the histosphere associated with grasses (Gramineae, Caryphyllaceae, Crucifereae) and rice cultivars in saline and reclaimed saline paddy soils were varied with species and rice cultivars. The fraction of aerobic heterotrophic $N_2$-fixing bacteria to the total aerobic heterotrophic bacteria were averaged to eighteen percent in the histosphere of grasses and rice. Acetylene reducing activity of these bacteria were ranged from 1 to 24 n mole/tube/hr. Most of the bacteria strains were predominated of hydrogen utilizing bacteria. The majority of these bacteria were closed to Pseudomonas, Azospirillum, Klebsiella and Agrobacter.

• 상하수도학회지
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• 제21권3호
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• pp.287-294
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• 2007

When we use the circular pipes for wastewater and storm water, we should be known the characteristics of the flow for accurate design. To elevate the design accuracy, we want to know the profile of flow. The roughness coefficient in the Manning equation is constant, but in actuality changed with the relative depth in circular pipe. This study was conducted to calculate the relative normal depth in changing the roughness coefficient (named relative roughness coefficient) with the relative depth in the analysis of gradually varied flow in the circular pipe by Newton-Raphson method. We performed the analysis of gradually varied flow using the relative normal depth and the relative roughness coefficient. We presented the 12 flow profiles with the relative depth and the relative roughness coefficient in circular pipe. The flow classification considering relative depth in circular pipe is available to analyse gradually varied flow profiles.

• 상하수도학회지
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• 제18권3호
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• pp.385-391
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• 2004

This paper examines the applicability of DAF-system to the domestic sewers for the effective CSOs treatment. The procedures for the experiment include mainly two steps. One is to analyse the water qualities and settling test of the CSOs and the other focuses on general characteristics of the CSOs such as the removal efficiency of pollutant, the distribution of particle size and mass balance of DAF-system. The result of this study show that the application of DAF-system is more effective and economical than the existing treatment systems because it has two removal mechanisms of sedimentation and flotation simultaneously.

• 상하수도학회지
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• 제21권6호
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• pp.717-726
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• 2007

Fully-grown flocs in a mixing tank of membrane filtration with dead-end membrane are ruptured while passing through a pump and the ruptured flocs are aggregated again in a Membrane-Feed-Pipe (MFP). To look at more details, this study tries to relate the reaggregation to a parameter of mixing intensity in MFP, i.e., G-value. The G-value is a function of Reynolds number, pipe diameter, friction factor and average velocity in MFP. To deal with polydispersity condition, we develop a representative particle size called in this study EDPD (Effective Diameter for Polydispersity condition in Dead-end filtration). The experimental results show that as the G-value increases, the EDPD decreases and also the cake resistance increases. Through comparison between EDPD and cake resistance, these results show that cake resistances are controlled by reaggregation phenomenon in MFP. The effect of detention time in MFP, however, does not affect the reaggregation of the broken flocs as G-values are increased.

• 상하수도학회지
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• 제7권2호
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• pp.34-38
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• 1993

An experimental study was conducted to investigate the effects of chlorine dioxide and ozone on reduction of THM(trihalomethane) formation. Precursor concentration, chlorine concentration, reaction time, pH, and temperature were governing compornents of THM formation. When other conditions are constant, THM formation increased linearly with precursor concentration increased. THM formation increased when pH increased from 5 to 9. In combined treatment with chlorine and chlorine dioxide, chlorine treatment after chlorine dioxide treatment made less THM than any other case does. Ozonation reduced THMFP(THM formation potential) of THM precursor. THMFP decreased exponentially with reaction time increased. Also biodegradability of humic acid was enhanced by ozonation.

• 상하수도학회지
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• 제27권6호
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• pp.787-796
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• 2013

Sewer joint-related defect is one of the most common domestic sewer defects along with the lateral pipe problem. However, there are currently no criteria that precisely assess the joint-related sewer defects. Therefore, this study examined the joint-related sewer defects found in domestic circumstances, classified them according to the suggested defect code, and presented the examples of defect pictures. Each defect code was organized as the process of out of pipeline alignment (OPA) which shows the progress in deterioration. Each defect was classified into 5 grades depending on appropriate repair and rehabilitation method. The result of this study is expected to be useful for domestic CCTV inspectors to assess the sewer condition and helpful for managers to make a decision of repair and rehabilitation.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2010년도 정기 학술대회
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• pp.666-669
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• 2010

여러 가지 지하시설물 중 국가 주요 자원의 수송망을 책임지는 주요구조물인 수도관, 가스관등의 배관구조물은 접근이 쉽지 않은 지하공간에 복잡하게 연결되어 있어 그 중요성에 비해 유지, 관리, 보수가 쉽지 않았다. 이러한 배관구조물을 균열, 조인트 풀림 등의 손상으로부터 보다 안전하고 효율적으로 관리하기 위하여 상시적 배관구조물 손상진단기법을 연구하였다. 이를 위해 배관 구조물 시험체에 볼트풀림, notch 등과 같은 손상에 대하여 대표적인 압전센서인 PZT와 MFC를 부착하고 임피던스기법 및 유도 초음파기법을 적용하여 볼트풀림개수, notch 손상개수 증가에 따른 출력신호를 반복 계측하였다. 객관적인 평가를 위해 계측된 신호를 신호처리기법인 웨이블렛 변환을 수행하고, RMSD 및 1-CC의 손상지수를 사용하여 구조물손상을 정량화 시켰으며 이를 토대로 구조물의 건전성의 기준이 되는 임계값을 설정함으로서 임피던스와 유도초음파 두 검색기법을 이용한 상시적 배관구조물 건전성 모니터링의 가능성을 살펴보았다.

• 세라미스트
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• 제4권3호
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• pp.122-127
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• 2001

나노복합재료는 기계적, 전기적, 전자기적 특성을 향상하거나 새로운 기능을 갖는 신소재를 제조할 수 있는 가능성으로 인하여 많은 주목을 받고 있다. 우수한 특성을 갖는 나노복합재료의 제조에 있어서 주의할 점은, 나노복합재료가 다른 세라믹재료에 비하여 제조공정에 민감하게 영향을 받는다는 것이다. 출발원료, 혼합방법, 건조방법 등의 선택에 따라서 특성이 향상될 수도 있고 역으로 저하될 수도 있다. 이러한 현상은, 초미립자의 비표면적이 크기 때문에 균일한 분산이 어렵고 응집이 발생하기 쉽기 때문이라 생각된다. $Si_3N_4/SiC$ 나노복합재료의 경우는 고온강도와 열피로에 대한 저항성이 획기적으로 향상되어 $1400^{\circ}C$ 이상에서도 사용할 수 있는 초고온재료로로서의 가능성을 갖고 있다. 그러나 이러한 나노복합재료의 실용화를 위해서는 제조공정이 단순하고, 경제성이 있는 신 공정의 개발과 GPS 소결 등에 관하여 보다 많은 연구가 필요하다. 그러나 계속적인 환경오염에 관한 국제적 규제의 강화, 국제 원유가의 상승 등은 열기관의 열효율 향상을 위해서 초고온에서 사용할 수 있는 나노복합재료와 같은 재료를 요구할 것이며, 또한 정보통신산업 발전에 따른 소형화, 고 기능화는 우수한 특성과 새로운 기능을 갖는 나노복합재료의 개발과 실용화를 앞당기는 계기가 될 것으로 생각된다.

• Applied Biological Chemistry
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• 제5권
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• pp.49-51
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• 1964

Results obtained from Leaves and soils may be summarized as follow; It was found that the rice plant which grown under the deficiency of silica, manganese and magnesium become very susceptible to Helminthosporium leaf spot, as compared with that grown under normal condition. While no close correlation was found in nitrogen, phosporus and potassium between the health and disease. On the other hand, reducible manganese content of normal paddy soils is also 13.2 times as high as that of diseased paddy soils (Akioch soil) Considering from the results, it seems to have certain relationship between resistance to Helminthosporium and unbalance of inorganic elements in rice blade.