다공성 매질내에서 CMC로 표면개질된 영가철 나노입자의 이동 특성에 관한 연구

조윤철,최상일,Cho, Yun-Chul,Choi, Sang-Il 한국지하수토양환경학회 2009 지하수토양환경 Vol.14 No.6

카르복시메틸 셀룰로즈(carboxymethyl cellulose, CMC)와 같은 안정화제는 오염된 지하대수층에서 영가철 나노입자의 이동을 촉진할 수 있다. 본 연구에서는 CMC로 개질된 영가철 나노입자의 이동성을 컬럼실험을 통해 조사하였다. CMC로 개질된 100 mg/L 영가철 나노입자는 모래로 이루어진 공극매체에서 이동이 가능하였다. 하지만 비개질된 영가철 나노입자는 제조된 용액에서 쉽게 엉김현상이 나타났고, 모래로 이루어진 공극매체에서 통과하지 못했다. pH가 7일 때 영가철 나노입자 약 80%가 컬럼을 통과하여 흘러나왔다. pH가 5이하로 감소할 때는, 100%의 CMC로 개질 된 영가철 나노입자는 100%가 흘러나왔다. 이온강도세기 실험에서 $Na^+$과 $Ca^{2+}$ 이온의 농도가 증가함에 따라 CMC로 개질된 영가철의 이동성이 다소 감소하는 것으로 나타났다. 점토과 자연유기물(natural organic matter, NOM) 영향 실험에서는, 1과 5%의 점토와 100과 1000 mg/L의 자연유기물질은 CMC로 개질된 영가철 나노입자의 이동성에는 크게 영향을 주지 못하는 것으로 나타났다. 본 실험의 결과로부터 CMC로 개질된 영가철 나노입자는 다양한 이온세기, 자연유기물농도 및 점토함량을 가진 토양내에서도 효과적으로 이동될 것으로 기대된다. Carboxymethyl cellulose (CMC) as stabilizer is expected to facilitate in-situ delivery of zero-valent iron (ZVI) nanoparticles in a contaminated aquifer because it increases dispersity of ZVI nanoparticles. This work investigated the transport of CMC-stabilized ZVI nanoparticles (CMC-Fe) using column breakthrough experiments. The ZVI nanoparticles (100 mg/L Fe) were transportable through sand porous media. In contrast, non-stabilized ZVI nanoparticles rapidly agglomerate in solution and are stopped in sand porous media. At pH 7 of solution approximately 80% CMC-Fe were eluted. When the pH of solution is below 5, 100% CMC-Fe were eluted. These results suggest that the mobility of CMCFe was increased as pH decreases. In the mobility test under different ionic strengths using $Na^+$ and $Ca^{2+}$ ions, there was no signigficant difference in the mobility of CMC-Fe. Also, in the experiments of effect of clay and natural organic mater (NOM) on the mobility of ZVI, there was no significant difference in the mobility of CMC-Fe not only between 1 and 5% clay, but 100 and 1000 mg/L NOM. The results from this work suggests that the CMC-Fe nanoparticles could be easily delivered into the subsurface over a broad range of ionic strength, clay and NOM.

Raw 파일 변환을 통한 디지털 존 시스템

조윤철,하동환,손영호 영상예술학회 2006 영상예술연구 Vol.9 No.-

산화막을 갖는 지르칼로이 산화의 흡착물 영향

조윤철,박광헌 慶熙大學校 材料科學技術硏究所 1995 材料科學技術硏究論集 Vol.8 No.-

The oxidation behaviors of Zircaloy in air are studied by measuring the weight gains of specimens. The oxidation study of Zircaloy in air is relatively few, comparing to the enormous amount of works of Zircaloy corrosion in water or steam. Researches about oxidation mechanism in air, exposured Zircaloy claddings to the LiOH which is added to the primary coolant, and to NaCl which is from the salty coasted wind have not been carried out yet. To depict integrities of these Zircaloy claddings of spent fuels, Zircaloy specimens produced by W/H were oxidised at the temperature range between 400℃ and 500℃ in the electric furnaces. 8 types of the specimens are prepared. ① etched Zircaloy, ② NaCl adsorbed, ③ LiOH adsorbed, ④LiF adsorbed, ⑤NaF adsorbed, and ⑥ KF adsorbed Zircaloy specimens on the pre-existing oxide. NaCl, NaF, KF, and NaF accelerate the oxidation rate of Zircaloy cladding in air. Care should be taken in the management of spent fuels not to be exposed to salty air. Adsorbates like NaF can be used as a oxidation enhancer in volume reduction of Zircaloy claddings.

전술 애드 혹 네트워크에서 다중 홉 전송을 위한 자원 예약 및 백오프 기법

조윤철,윤선중,고영배,Cho, Youn-Chul,Yoon, Sun-Joong,Ko, Young-Bae 한국군사과학기술학회 2012 한국군사과학기술학회지 Vol.15 No.1

In multi-interface multi-channel(MIMC) based tactical ad hoc networks, QoS support for required operational capacity is one of the main challenging issues for multi-hop transmissions. To support QoS in such a harsh environment, we propose a novel MAC scheme to minimize multi-hop as well as per-hop delay. The current IEEE 802.11 MAC protocols should contend to reserve the channel resource at every hop by each sender. The every-hop channel contention results in a degradation of end-to-end delay for multi-hop transmissions. The basic idea of our scheme is to make a "multi-hop reservation" at the MAC layer by using the modified RTS frame. It contains additional information such as destination information, packet priority, and hop count, etc. In addition, we differentiate the contention window area according to the packet priority and the number of hops to deliver packets in the predefined allowed latency. Our scheme can minimize the multi-hop delay and support the QoS of the critical data in real time(i.e., VoIP, sensing video data, Video conference between commanders). Our simulation study and numerical analysis show that the proposed scheme outperforms the IEEE 802.11 MAC.

2P-511 A Preliminary Study on the Fabrication of 3D Printable Electrode Ink for Li-ion Batteries

조윤철,강석현,이창우 한국공업화학회 2017 한국공업화학회 연구논문 초록집 Vol.2017 No.1

With advent of the forth industrial revolution, 3D printing technic has become emerging technology along with internet of things (IoT), artificial intelligence (AI) and so on. Various shape of batteries would be required that could be applied to variety of things which did not require the energy source in the past. In this study, we have focused on optimization of composition and rheology for electrode ink. The electrode which is fabricated by attempted electrode ink is characterized and compared with the electrode produced by traditional method.

공기중에서 지르칼로이 산화 거동 : 흡착물의 영향 Effects of Adsorbate

조윤철,박광헌 慶熙大學校 材料科學技術硏究所 1994 材料科學技術硏究論集 Vol.7 No.-

In order to get the results about the data for the corrosion of the Zircaloy-4 specimens which were purely etched, adsorbated on the LiOH and NaCl, and oxidized to the "Post-Transition" point in air, the specimens were oxidized in the electrical furnace set at the temperature of the 400℃, 450℃, and 500℃ for long time(approximately 700 hours). According to the results of the oxidation velocities among the specimens, the velocities of the adsorbated specimens on the NaCl, LiOH and the post-transition showed higher than the specimens of the purely etched specimens. Compared to the results of the Suzuki, the results of the purely etched specimens showed close similiarity to each other.

자외선 사진 연구

조윤철 한국사진학회 2000 AURA Vol.7 No.1

Many scientists informed us not only that light helps us to see a thing but also that it includes invisible light which can hardly be conceived but exists still as a part of light. Among the pictures using such invisible light, ultraviolet picture is one of the most commonly known type together with infrared photography. The main purpose of the ultraviolet photography lies in providing information unavailable from other photographs using other lights such as visible light and infrared light. Unlike the way of visible light to show the peculiar color in things through reflection and extinction of the light, some things absorb ultraviolet light, while other things reflect it, fully or partially. This kind of effect can be recorded in the ultraviolet photos. Presently, in terms of infrared picture, it is rather well-known and many good works of such photos have been introduced in Korea. However, compared to it, ultraviolet photo seems to be relatively unfamiliar. Thus, I've tried to introduce the use of ultraviolet light in photograph, focusing on the fact that such invisible but definitely existing part of light responds to most of the currently used photographic emulsion. Considering that we photographers are more interested in creative use of such technique for more diverse and colorful works in its application, than the experimental characteristics of scientific pictures. If we take it over and develop it in other ways helpful for the creation of original works. it will furnish us with quite useful tool for indefinite variations.

인공위성 자세결정 시스템을 위한 관성좌표계에서의 등가 오차모델

조윤철,유명종,정재우,방효충,탁민제 한국항공우주학회 2002 한국항공우주학회 학술발표회 논문집 Vol.- No.-

가변구조 제어기를 이용한 인공위성의 자세제어

조윤철,박수홍,조겸래 제어로봇시스템학회 1990 제어로봇시스템학회 국내학술대회 논문집 Vol.1990 No.10

한국의 전시 해상수송능력 분석

조윤철,이상진 한국국방경영분석학회 2002 한국국방경영분석학회지 Vol.28 No.1

This study focuses primarily on the construction of the wartime sealift operation model from US to Korea. There are some uncertainties in the process of sealift operation such as the procurement rate of materiel in US, the distribution of KFS on four initial position locations at the start of the activation, and the number of ports and berths in the SPOES and SPODS. The sealift capability, based on the allocation of sealift assets such as the number of vessels, berths, and ports, is evaluated through simulation. The simulation is executed with a baseline wartime scenario and then the results are analyzed through a sensitivity analysis. The military planner may use of this model as a standard for establishing effective and concrete sealift operation plan in the near future.