응축방식을 이용한 담수화 시스템의 성능예측을 위한 분석연구

김철호,김원일,최재영,김재철,김민선,Kim, Chul-Ho,Kim, Won-Il,Choi, Jea-Young,Kim, Jae-Choul,Kim, Min-Sun 대한기계학회 2014 대한기계학회 논문집. Transactions of the KSME. C, 산업기술과 혁신 Vol.2 No.1

본 연구에서는 태양열에 의해 증발된 해수면에서의 수증기를 응축의 원리를 이용하여 담수의 생산이 가능한 친환경 담수장치(Eco-friendly Desalination System)를 고안하고, 가능성을 판단하는데 연구의 목적을 두고 있다. 응축 열전달 공식을 이용하여 습공기의 물성변화에 따른 연간 응축수 생산량을 예측하였으며, 항온항습챔버의 실험을 통해 실제 습공기조건 변화에 따른 응축량을 측정하였다. 습공기의 이론 응축률과 실험을 통해 측정한 실제 응축률의 오차율을 산출하였으며, 오차의 원인을 분석하고 응축률 보정계수인 응축계수와 점성계수를 구하여 보정된 이론 응축률 공식에 도출하였다. 보정된 응축률 식을 이용하여 설계된 규모의 풍력터빈연간 생산 가능한 담수량을 산출한 결과 최대 연간 약 2,927톤 정도의 담수를 생산할 수 있다는 사실을 알 수 있었다. A new concept of an Eco-friendly desalination method is introduced in this study. The main idea of the desalination method of seawater is the condensation of the vaporized seawater by solar heat energy on the surface of seashore. The wind turbine blade plays a role of heat exchanger condensing the vaporized water in the air. In this analytical study, the availability of the proposed desalination system was studied. First, an analytical condensation theory of the vaporized water in air was arranged and the parametric study was conducted to estimate the amount of freshwater produced from the system with the change of the temperature difference between the humid air and turbine blade, and the relative humidity in air, and wind speed. From the analytical calculation, 2,927(ton/year) of freshwater was produced at the vertical-type wind turbine (Diameter=4m, Height=3m) as the relative humidity is 100%, the temperature difference between the impeller blade and the humid air is $40^{\circ}C$ and the wind speed is 10m/s.

장력법을 적용한 박판블록의 변형제어에 관한 연구

김철호,양종수,김호경,Kim, Cheol-Ho,Yang, Jong-Soo,Kim, Ho-Kyung 대한용접접합학회 2007 대한용접·접합학회지 Vol.25 No.6

The weld-induced deformation is more serious in thin plates than in thick plates because heat affect zone of thin plates is wider than that of thick plates and in addition internal and external constraints have much more influence upon weld-induced deformation of thin plates. This paper deals with the application of the mechanical tensioning method to butt weld of thin plates to reduce the transverse and longitudinal deformation. In order to investigate the quantitative effect of tensioning method upon the reduction of angular deformation and shrinkage in longitudinal and transverse direction of weld line, butt welding test has been carried out for several thin plate specimens with varying plate thickness and magnitude of tensile load. From the present experimental study, it has been found that the tensioning method is very effective in reducing the weld-induced residual stress as well as the weld-induced deformation.

초전도 결정의 저온 비열 점프의 자기장 의존성

김철호,Kim, Cheol-Ho 한국재료학회 2011 한국재료학회지 Vol.21 No.2

Specific heat of a crystal is the sum of electronic specific heat, which is the specific heat of conduction electrons, and lattice specific heat, which is the specific heat of the lattice. Since properties such as crystal structure and Debye temperature do not change even in the superconducting state, the lattice specific heat may remain unchanged between the normal and the superconducting state. The difference of specific heat between the normal and superconducting state may be caused only by the electronic specific heat difference between the normal and superconducting states. Critical temperature, at which transition occurs, becomes lower than $T_{c0}$ under the influence of a magnetic field. It is well known that specific heat also changes abruptly at this critical temperature, but magnetic field dependence of jump of specific heat has not yet been developed theoretically. In this paper, specific heat jump of superconducting crystals at low temperature is derived as an explicit function of applied magnetic field H by using the thermodynamic relations of A. C. Rose-Innes and E. H. Rhoderick. The derived specific heat jump is compared with experimental data for superconducting crystals of $MgCNi_3$, $LiTi_2O_4$ and $Nd_{0.5}Ca_{0.5}MnO_3$. Our specific heat jump function well explains the jump up or down phenomena of superconducting crystals.

저온에서 초전도 결정의 비열 점프

김철호,Kim, Cheol-Ho 한국결정성장학회 2011 한국결정성장학회지 Vol.21 No.1

본 논문에서는 먼저 저온에서의 초전도 결정의 비열 점프를 임계 온도의 함수로 구하였다. 다음에, 구한 비열 점프의 부호와 크기 등을 분석하여 여러 가지 실험적인 사실들을 예측하였다. 마지막으로 우리가 예측한 실험 사실과 실제의 실험이 일치하는지 비교하였다. 이론적으로 구한 비열점프는 $YNi_2B_2C$ 결정의 비열 점프 업 과 비열 점프 다운 현상을 비교적 잘 설명한다. 특히 매우 낮은 온도에서는 상전도-초전도 전이 시에 비열이 점프 다운된다는 주목할 만한 이론적 예측을 실험 결과를 통해 확인할 수 있었다. In this paper, firstly we have derived and presented the specific heat jump as a function of the critical temperature. Secondly, we have analyzed the sign and magnitude of the derived specific heat jump and predicted the expected experimental results. And lastly, we have compared the expected experimental results with the real experimental results. Theoretically derived specific heat jump is considerably compatible with the specific heat jump up and down phenomena of the $YNi_2B_2C$ crystal. Especially, the remarkable theoretical prediction-hat the specific heat would jump down during the normal state-to-superconducting state transition at extremely low temperatures-have been confirmed by the experimental results.

공해요인을 제거한 축산단지의 육성방안 - 충남지역 사례연구 -

김철호,박창식,이봉덕,권용대 ( Chul Ho Kim,Chang Sik Park,Bong Duck Lee,Yong Dae Kwon ) 한국축산경영학회 1994 韓國畜産經營學會誌 Vol.10 No.1

하천의 어제, 오늘 그리고 내일 1 - 원주천의 역사와 문화

김철호,Kim, Cheol-Ho 한국하천협회 2013 하천과 문화 Vol.9 No.1

Recombinant Cl - amylase 의 세포내 수송에 있어서 Signal sequence 의 역할

김철호,권석태,이대실 ( Cheorl Ho Kim,Suk Tae Kwon,Dae Sil Lee ) 생화학분자생물학회 1991 BMB Reports Vol.24 No.4

The possible signal sequence capable of transporting the Cl-amylase from B. circulans has been analyzed with in vitro mutagenesis techniques. A residue in the NH₂-terminal region near to the postulated cleavase site was changed by site-directed mutagenesis from a serine into proline and threonine. Comparison of Cl-amylase acitivity outside and inside the cell in strains containing the cloned wild type and mutagenised genes showed that this single amino acid prevents largely the translocation of the enzyme in the periplasmic space: in transformed E. coli the proline -mutant Cl-amylase showed 5% secretion of wild type Cl-amylase and threonine-mutant Cl-amylase.

Redis를 활용한 Web Service 성능 향상

김철호,박경원,최용락,Kim, Chul-Ho,Park, Kyeong-Won,Choi, Yong-Lak 한국정보통신학회 2015 한국정보통신학회논문지 Vol.19 No.9

To improve performance, most of Web Services produce and manage User Access Logs. Through the Access Logs, the record provides information about time when the most traffic happens and logs and which resource is mostly used. Then, the log can be used to analyze. However, in case of increasing high traffics of Web Services at the specific time, the performance of Web Service leads to deterioration because the number of processing User Access Logs is increasing rapidly. To solve this problem, we should improve the system performance, or tuning is needed, but it makes a problem cost a lot of money. Also, after it happens, it is not necessary to build such system by spending extra money. Therefore, this paper described the effective Web Service's performance as using improved User Access Log performance. Also, to process the newest data in bulk, this paper includes a method applying some parts of NoSQL using Redis. 대부분의 Web Service는 성능 개선을 위해 사용자 접속 로그를 생성하여 관리한다. 생성된 접속 로그를 통해 트래픽이 많이 발생하는 시간대와 어떤 Resource가 많이 사용되는지 확인할 수 있으며 로그 분석을 통해 Web Service의 성능 측정 및 개선하는데 이용된다. 하지만, 많은 공공부문 Web Service와 같이 일정 기간 동안에 접속량이 증가할 때, 처리 할 사용자 접속 로그 수 증가로 인해 Web Service의 성능이 저하된다. 이를 해결하기 위해, 시스템의 성능을 개선하거나 튜닝을 필요로 하지만 많은 비용이 발생하게 되며 일정한 시간이 지나면, 사용자의 접속이 줄어들게 되어 더 많은 비용이 발생한다. 본 논문에서는 사용자 접속 로그 처리의 성능을 개선을 통한 Web Service의 성능개선을 제안한다. 또한, 최근 대용량 데이터를 처리하기 위하여 많이 사용되고 있는 Redis를 활용하여 NoSQL을 일부 적용한 방법을 제안한다.

Moraxella sp. CK-1 의 세포외 효소에 의한 Anabaena cylindrica 세포벽의 분해

김철호,최영길,민병례 ( Chul Ho Kim,Yong Keel Choi,Byung Re Min ) 한국환경생물학회 1997 환경생물 : 환경생물학회지 Vol.15 No.1

Moraxella sp. CK-1 has been known to inhibit the growth of cyanobacteria including A. cylindrica. This growth inhibition by the bacteria was accomplished through the secretion of lytic enzyme (s) out of the bacterial cells. Extracellular cell wall lytic and proteolytic activity, which began to appear at the early exponential growth phase, changed similarly during the growth of Moraxella sp. CK-1. Extracellular cell wall lytic enzyme showed a temperature optimum of 60~70℃, a temperature stability of up to 60℃, and a pH optimum of 9.0. The lytic activity was enhanced by several enzyme stabilizers, chemicals, and metal ions except Ca^2+ and Mn^2+. Fe^3+ and Cu^2+ ions inhibited the lytic activity almost completely. The lytic enzyme was believed to be amidase or endopeptidase from the result that free amino groups in substrate solution increased when SDS-insoluble peptidoglycan was treated with extracellular enzyme(s) of Moraxella sp. CK-1.

Biodegradation of Chlorpyrifos (CP) by a Newly Isolated Naxibacter sp. Strain CY6 and Its Ability to Degrade CP in Soil

김철호,최진상,장인석,조계만,Kim, Chul Ho,Choi, Jin Sang,Jang, In Surk,Cho, Kye Man The Microbiological Society of Korea 2013 미생물학회지 Vol.49 No.1

A bacterium, isolated from a vegetable field in a plastic film house and named strain CY6 was capable of biodegrading chlorpyrifos (CP). Based on the phenotypic features and the phylogenetic similarity of 16S rRNA gene sequences, strain CY6 was identified as a Naxibacter sp.. CP was utilized as the sole source of carbon and phosphorus by Naxibacter sp. CY6. We examined the role of this Naxibacter sp. in the degradation of other OP insecticides under liquid cultures. Parathion, methyl parathion, diazinon, cadusafos, and ethoprop could also be degraded by Naxibacter sp. CY6 when they are provided as the sole sources of carbon and phosphorus. Additionally, Naxibacter sp. CY6 ($10^8$ CFU/g) added to soil with CP (100 mg/kg) resulted in a higher degradation rate of approximately 90% than the rate obtained from uninoculated soils. These results highlight the potential of this bacterium to be used in the cleanup of contaminated pesticide soil. 채소 재배 비닐하우스 토양으로부터 chlorpyrifos (CP) 분해능을 지니고 있는 CY6 균주를 분리하였다. 형태학적 특징 및 16S rRNA 염기서열의 계통발생학적 유사성을 기초로 CY6 균주는 Naxibacter sp.로 확인되었다. CP는 Naxibacter sp. CY6 의해 탄소 및 인의 단일원으로 이용되었다. 우리는 액체배양에서 Naxibacter sp. CY6의 다른 OP 살충제 분해 양상을 살펴 보았다. Naxibacter sp. CY6는 parathion 및 methyl parathion, diazinon, cadusafos, ethoprop를 분해할 수 있었으며, 이 때 이들은 탄소 및 인의 단일원으로 제공되었다. 또한, CP (100 mg/kg)가 함유된 토양에 Naxibacter sp. CY6 ($10^8$ CFU/g)를 접종한 것이 접종하지 않은 토양에서 보다 약 90%의 높은 분해 정도를 나타냈었다. Naxibacter sp. CY6는 살충제가 오염된 토양의 정화에 사용할 수 있는 잠재성을 지니고 있다.