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.

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.

Raw 파일 변환을 통한 디지털 존 시스템

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

뇌 종양내 항암제 치료를 위한 항암제 방출용 생분해성 폴리머 개발- 체외실험 결과

조윤철,조한진,안정호,이원정,윤수한 대한신경외과학회 2004 Journal of Korean neurosurgical society Vol.35 No.4

Objective : The authors present two polymers as carriers of anti-neoplastic agents for intratumoral chemotherapy. We investigated in vitro tumor cytotoxicity againt C6 glioma cells with 20ul cis-platinum(CDDP)-polymer. Methods : We firstly developed new two thermosensitive sol-gel reversible polymer(poly-2 and poly-6) by random copolyerization from ethylene glycol and caprolactone polymer that is sol state over 50°C but changed gradually to gel less than 50°C We evaluated the time-related release profiles of 10mg cisplatin from CDDP-Poly 2 and CDDPPoly 6 in 25ml of pH 7.4 phosphate buffer saline using UV spectrophotometer during 31days. We cultured C6 glioma cell line in 10cm round plates for 2 days and added 20㎕ of CDDP-polymer containing 30uM of CDDP into the center of each plate. We counted C6 cell number every 12 hours for 72 hours at same 3 sites of each 6 well plates. Results : UV spevtrophotometry showed total 12.6% of CDDP released from CDDP-poly2 and total 56.9% of CDDP from CDDP-poly6 on 31 days. Both carrier polymer showed total released amount of CDDP directly correlated with time without initial dumping effect. The CDDP released from 20㎕ of CDDP-poly2 and CDDP-poly6 in 48 hours showed cytotoxicity to C6 glioma cells more than 50% in vitro cell culture system. Conclusion : This results suggest that less than 20㎕ CDDP-polymer could be applied in vivo brain tumor model to show significant cytotoxicity.

가변구조 제어기를 이용한 인공위성의 자세 제어 ( Attitude Control of Satellite by Variable Structure Controller )

조윤철,박수홍,조겸래 대한전자공학회 1990 대한전자공학회 학술대회 Vol.1990 No.01

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.

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.

질산화 활성슬러지 내에서의 클린다마이신 항생제 생분해

조윤철,김이형,김성표 한국습지학회 2011 한국습지학회지 Vol.13 No.1

본 연구의 목적은 미량오염물질인 클린다마이신(Clindamycin) 항생제의 생분해성을 질산화 슬러지내에서 평가하는 것이다. 우선 단기간 배치 실험(Batch)을 통한 10ppb의 클린다마이신 생분해 실험결과, 클린다마이신이 반으로 줄어드는 시간 (t0.5)은 질산화 슬러지내에서는 9.1시간으로 측정되었으나, 질산화가 저해된 슬러지내에서는 t0.5 시간이 26.1시간으로 증가하였다. 본 실험을 통해, 클린다마이신 분해산물이 질산화 슬러지내에서 발견되었고 이는 clindamycin-sulfoxide (m/z 441)인 것으로 추정되었다. 이 분해산물은 항생능력이 있는 것으로 판단되었다. 이 클린다마이신 분해산물은 장기간 배치실험을 통해서도 줄어들지 않는 것으로 관찰 되었다. 따라서, 활성슬러지를 통한 클린다마이신의 완전 생분해는 쉽지 않은 것으로 판단되었다.

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.

군사작전 효과분석을 위한 시뮬레이션 방안 연구

조윤철 대한산업공학회 2018 대한산업공학회 춘계학술대회논문집 Vol.2018 No.4