황산 환경에서 Fe-Si, Ni-Ti계 및 Ni 합금의 내부식성 특성

권혁철,김동진,김홍표,박지연,홍성덕,Kwon, Hyuk-Chul,Kim, Dong-Jin,Kim, Hong-Pyo,Park, Ji-Yeon,Hong, Seong-Deok 한국재료학회 2011 한국재료학회지 Vol.21 No.1

Methods of producing hydrogen include steam reforming, electrochemical decomposition of water, and the SI process. Among these methods, the Sulfur iodine process is one of the most promising processes for hydrogen production. The thermochemical sulfur-iodine (SI) process uses heat from a high-temperature-gas nuclear reactor to produce $H_2$ gas; this process is known for its production of clean energy as it does not emit $CO_2$ from water. But the SI-process takes place in an extremely corrosive environment for the materials. To endure SI environments, the materials for the SI environment will have to have strong corrosion resistance. This work studies the corrosion resistances of the Fe-Si, Ni-Ti and Ni Alloys, which are tested in SI-process environments. Among the SI-process environments, the conditions of boiling sulfuric acid and decomposed sulfuric acid are selected in this study. Before testing in boiling sulfuric acid environments, the specimens of Fe-4.5Si, Fe-6Si, Ni-4.5Si, Ni-Ti-Si-Nb and Ni-Ti-Si-Nb-B are previously given heat treatment at $1000^{\circ}C$ for 48 hrs. The reason for this heat treatment is that those specimens have a passive film on the surface. The specimens are immersed for 3~14 days in 98wt% boiling sulfuric acid. Corrosion rates are measured by using the weight change after immersion. The corrosion rates of the Fe-6Si and Ni-Ti-Si-Nb-B are found to decrease as the time passes. The corrosion rates of Fe-6si and Ni-Ti-Si-Nb-B are measured at 0.056 mm/yr and 0.16 mm/yr, respectively. Hastelloy-X, Alloy 617, Alloy 800H and Haynes 230 are tested in the decomposed sulfuric acid for one day. Alloy 800H was found to show the best corrosion resistance among the materials. The corrosion rate of Alloy 800H is measured at -0.35 mm/yr. In these results, the corrosion resistance of materials depends on the stability of the oxide film formed on the surface. After testing in boiling sulfuric acid and in decomposed sulfuric acid environments, the surfaces and compositions of specimens are analyzed by SEM and EDX.

스크린 높이와 서류 고정대 위치에 따른 경부 주위 근육의 활성 정도 비교

권혁철,정동훈,Kwon, Hyuk-Cheol,Jeong, Dong-Hoon 대한물리치료학회 2001 대한물리치료학회지 Vol.13 No.3

Using Video Display Terminals(VDT) in the working environment often causes health complaints in the neck and shoulder region. This study was conducted on ten subjects, in order to investigate the change of electromyographic activities in the neck region(sternocleidomastoid muscle, upper trapezius muscle and erector muscle of cervical spine)with regards to the screen height and document holder position. A total of six different conditions of screen height and document holder position were measured during subjects performed a text-entry task for a duration of 10min. The raw EMG signal was transmuted into the root mean square(RMS). Two-way ANOVA for repeated measures was used to analyse the effects of the two factors. As a result, changing the screen height and document holder position has no effect on electromyographic activities in the neck region.

한국적 환경을 반영한 사용자 인터페이스 구현의 가능성

권혁철(Hyuk-Chul Kwon) 한국정보과학회 1995 한국정보과학회 학술발표논문집 Vol.1995 No.2

대체우유 산업 현황 및 전망

권혁철(Hyuk Cheol Kwon),정현수(Hyun Su Jung),한성구(Sung Gu Han) 한국축산식품학회 2023 축산식품과학과 산업 Vol.12 No.1

시맨틱웹과 온톨로지: 가능성과 한계

권혁철(Hyuk-Chul Kwon) 한국정보과학회 2006 정보과학회지 Vol.24 No.4

지역화폐 기획과 운영 간 상호 조응성에 관한 연구: 지역사랑상품권 운영 사례를 중심으로

권혁철(Kwon, Hyuk Chul) 동국대학교 사회과학연구원 2020 사회과학연구 Vol.27 No.3

지역화폐(지역사랑상품권)가 침체된 지역 경제를 활성화 시킬 수 있는 대안으로 주목받으면서 최근 지역화폐를 발행하는 지자체가 급증하고 있다. 그렇다면 지역화폐를 지역주민이 과연 얼마나 받아들이고 사용할까라는 문제의식에 기반을 두고 운영 실태 및 효과성에 대한 심층적인 실증의 필요성이 제기된다. 이를 위해 본 연구는 지역화폐 발행 지자체 및 민간단체 실무자 13명에 대한 심층면접을 통해 기획과 운영 간 상호 조응성을 살펴봄으로써 지역화폐 활용 가능성을 탐색하였다. 그 결과, 지역화폐 도입과 운영 과정, 운영 현장에서 작동되는 지역화폐 정책의 일련의 과정은 상호 조응이 있는 것으로 판단된다. 하지만 실제로 얼마나 발행 목적이 실현되고 있는가에 대한 판단은 섣불리 내릴 수가 없다. 지역화폐의 현주소가 도입 초기 단계로써 지역화폐의 대중성 확보가 우선시 되고 있기 때문이다. 또한 지역화폐가 지역주민들에게 기대 이상의 호응을 얻고 발행액이 증가하고 있지만, 지역화폐 도입 목적과 지역화폐가 추구해야할 가치가 불분명하다보니 지자체의 발행지속성에 대한 고민이 가중되고 있었다. 본 연구는 지역화폐를 발행하는 실무자의 목소리로부터 지역화폐 도입 및 운영 과정을 구체적으로 확인하는 연구로 의의가 있으며, 연구결과를 근거로 지역화폐 정책 목표 및 운영 방향에 대한 제도적, 실천적 함의를 제안한다. The number of local governments issuing local currency has been on the rise recently as local currency (regional gift certificate) has been seen as an alternative to invigorate the sluggish local economy. For local currency to be successful, careful analysis of the conditions for the introduction pre-determination is required. This study explored the prerequisites and availability of the introduction through in-depth interviews with 13 working-level officials of local governments and private organizations issuing local currency. As a result, the introduction and operation process of local currency and the series of regional currency policies that operate at the operation site are judged to have interaction correspondence. However, it is impossible to make a hasty judgment on how much the purpose of the issue has actually been realized. This is because the current status of local currency is the initial stage of introduction, and securing the popularity of local currency is a priority. Although local currency received more than expected responses from local residents and the amount of issuance was increasing, the purpose of introducing local currency and the value of local currency being pursued were unclear, raising concerns over the local government"s continuity of issue. This study is meaningful as it specifically identifies the process of introducing and operating regional currency from the voice of the person in charge of issuing regional currency, and proposed institutional and practical implications for regional monetary policy objectives and direction of operation based on the research results.

한국형 킬 체인(Korea Kill Chain)의 진단과 발전방향

권혁철(Kwon, Hyuk-Chul) 한국전략문제연구소 2014 전략연구 Vol.- No.64

2013년 3차 핵실험을 계기로 북한의 핵무기 위협이 현실로 다가오고 있다. 이에 한국군은 한국형 킬 체인과 한국형미사일방어체계(KAMD)를 전략적 대안으로 마련하고 이를 2020년 중반까지 완성하기 위해 체계구축을 서두르고 있다. 그러나 한국형 킬 체인은 고도의 기술과 많은 예산이 소요되는 만큼 적지 않는 난관이 예상된다. 이를 극복하고 핵미사일 표적을 신뢰성 있게 공격할 수 있는 체계가 구축되기 위해서는 많은 고민과 준비가 요구된다. 이에 본고는 한국형 킬 체인에 관한 선행연구와 추진실태를 분석하여 현재 또는 예상되는 문제점을 도출하고 발전방향을 다음과 같이 제시했다. 첫째, 한국형 킬 체인의 개념을 명확히 정립하여 군, 학계, 언론 등에서 그 의미를 공유할 필요가 있으며 유·무용론의 논쟁을 조기에 종식시킬 필요가 있다. 둘째, 한국형 킬 체인의 목표는 한국형 미사일방어체계와 연계하여 최적화시켜야 하며, 능동적 억제전략과 한미연합맞춤형억제전략과 연계하여 운용개념과 운용절차를 구체화해야 한다. 또 한미연합방위체제의 틀 속에서 운용하되 초기단계에서 한국형 킬 체인을 먼저 작동시킨 후에 미국이 가담하는 전략적 역할 분담이 필요하다. 셋째, 한국형 킬 체인의 능력은 정보·타격·지휘통제능력의 균형이 중요하며 이를 위해 정보 능력을 우선적으로 보강할 필요가 있다. 넷째, 한국형 킬 체인이 민감한 핵미사일을 타격하기 위한 것인 만큼 예상되는 부작용과 위험을 최소화하기 위한 다중적인 대책이 필요하다. North Korea’s nuclear threat is becoming a reality. As a response, Republic of Korea (ROK) military has prepared Korea Kill-Chain and Korea Air and Missile Defense (KAMD) as a strategic response options, and it is striving to complete the process by the middle of 2020. However, there are many barriers to remove as Korea Kill Chain requirers cutting edge technology and tremendous amount of budget. To overcome such difficulties and establish a system that can accurately strike nuclear targets, considerable preparation and investment are necessary. This thesis deduces current and potential problems by analyzing previous researches on Korea Kill Chain and current status of Korea Kill Chain development; and it also suggests plans for improvement as following: First, military, media, and academia should clearly establish and have consensus on Korea Kill Chain concept; also, debate on the effectiveness of Korea Kill Chain should end early. Second, the goal of Korea Kill Chain should be on optimizing(having the perfect offense-defense ratio) the effectiveness in correlation with KAMD and specifying employment concept and process in line with proactive deterrence strategy and tailored deterrence strategy. Also, while operating Korea Kill Chain within the frame of ROK-US Combined Defense System, ROK and US should have strategic role sharing, which ROK operates Korea Kill Chain first in the initial stage and allow US to join afterwards. Third, the balance among intelligence, strike, and C2 capability is important in establishing Korea Kill Chain capability. To achieve balance, reinforcing intelligence capability should be the priority. Fourth, as Korea Kill Chain is designed to strike North Korea’s nuclear missile, multiple options should be established to minimize potential side-effects and risks.

한국어 정보처리 : 어제와 오늘

권혁철(Hyuk-Chul Kwon) 한국정보과학회 1999 정보과학회지 Vol.17 No.12

강열점소성 유한요소법을 적용한 봉형상압연 공정설계에서의 공형 설계 및 롤속도 설정

권혁철(H.C.Kwon),김수영(S.Y.Kim),임용택(Y.T.Im) 한국소성가공학회 1999 압연 심포지엄 Vol.1999 No.8

고온화학세정환경에서 20 % EDTA 용액이 결함 전열관 (Alloy600)에 미치는 영향

권혁철 ( Hyuk Chul Kwon ) 한국부식방식학회(구 한국부식학회) 2016 Corrosion Science and Technology Vol.15 No.2

The transport and deposition of corrosion products in pressurized water nuclear reactor (PWR) steam generators have led to corrosion (SCC, denting etc.) problems. Lancing, mechanical cleaning and chemical cleaning have been used to reduce these problems. The methods of lancing and mechanical cleaning have limitations in removing corrosion products due to the structure of steam generator tubes. But high temperature chemical cleaning (HTCC) with EDTA is the most effective method to remove corrosion products regardless of the structure. However, EDTA in chemical cleaning aqueous solution and chemical cleaning environments affects the integrity of materials used in steam generators. The nuclear power plants have to perform the pre-test (also called as qualification test (QT)) that confirms the effect on the integrity of materials after HTCC. This is one of the series studies that assess the effect, and this study determines the effects of 20 % EDTA aqueous solution on defective tubes in high temperature chemical cleaning environments. The depth and magnitude of defects in steam generator (SG) tubes were measured by eddy current test (ECT) signals. Surface analysis and magnitude of defects were performed by using SEM/EDS. Corrosion rate was assessed by weight loss of specimens. The ECT signals (potential and depth %) of defective tubes increased marginally. But the lengths of defects, oxides on the surface and weights of specimens did not change. The average corrosion rate of standard corrosion specimens was negligible. But the surfaces on specimens showed traces of etching. The depth of etching showed a range on the nanometer. After comprehensive evaluation of all the results, it is concluded that 20 % EDTA aqueous solution in high temperature chemical cleaning environments does not have a negative effect on defective tubes.