• 제목/요약/키워드: Self diffusion

검색결과 386건 처리시간 0.029초

New Approaches for Overcoming Current Issues of Plasma Sputtering Process During Organic-electronics Device Fabrication: Plasma Damage Free and Room Temperature Process for High Quality Metal Oxide Thin Film

  • Hong, Mun-Pyo
    • 한국진공학회:학술대회논문집
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    • 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
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    • pp.100-101
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    • 2012
  • The plasma damage free and room temperature processedthin film deposition technology is essential for realization of various next generation organic microelectronic devices such as flexible AMOLED display, flexible OLED lighting, and organic photovoltaic cells because characteristics of fragile organic materials in the plasma process and low glass transition temperatures (Tg) of polymer substrate. In case of directly deposition of metal oxide thin films (including transparent conductive oxide (TCO) and amorphous oxide semiconductor (AOS)) on the organic layers, plasma damages against to the organic materials is fatal. This damage is believed to be originated mainly from high energy energetic particles during the sputtering process such as negative oxygen ions, reflected neutrals by reflection of plasma background gas at the target surface, sputtered atoms, bulk plasma ions, and secondary electrons. To solve this problem, we developed the NBAS (Neutral Beam Assisted Sputtering) process as a plasma damage free and room temperature processed sputtering technology. As a result, electro-optical properties of NBAS processed ITO thin film showed resistivity of $4.0{\times}10^{-4}{\Omega}{\cdot}m$ and high transmittance (>90% at 550 nm) with nano- crystalline structure at room temperature process. Furthermore, in the experiment result of directly deposition of TCO top anode on the inverted structure OLED cell, it is verified that NBAS TCO deposition process does not damages to the underlying organic layers. In case of deposition of transparent conductive oxide (TCO) thin film on the plastic polymer substrate, the room temperature processed sputtering coating of high quality TCO thin film is required. During the sputtering process with higher density plasma, the energetic particles contribute self supplying of activation & crystallization energy without any additional heating and post-annealing and forminga high quality TCO thin film. However, negative oxygen ions which generated from sputteringtarget surface by electron attachment are accelerated to high energy by induced cathode self-bias. Thus the high energy negative oxygen ions can lead to critical physical bombardment damages to forming oxide thin film and this effect does not recover in room temperature process without post thermal annealing. To salve the inherent limitation of plasma sputtering, we have been developed the Magnetic Field Shielded Sputtering (MFSS) process as the high quality oxide thin film deposition process at room temperature. The MFSS process is effectively eliminate or suppress the negative oxygen ions bombardment damage by the plasma limiter which composed permanent magnet array. As a result, electro-optical properties of MFSS processed ITO thin film (resistivity $3.9{\times}10^{-4}{\Omega}{\cdot}cm$, transmittance 95% at 550 nm) have approachedthose of a high temperature DC magnetron sputtering (DMS) ITO thin film were. Also, AOS (a-IGZO) TFTs fabricated by MFSS process without higher temperature post annealing showed very comparable electrical performance with those by DMS process with $400^{\circ}C$ post annealing. They are important to note that the bombardment of a negative oxygen ion which is accelerated by dc self-bias during rf sputtering could degrade the electrical performance of ITO electrodes and a-IGZO TFTs. Finally, we found that reduction of damage from the high energy negative oxygen ions bombardment drives improvement of crystalline structure in the ITO thin film and suppression of the sub-gab states in a-IGZO semiconductor thin film. For realization of organic flexible electronic devices based on plastic substrates, gas barrier coatings are required to prevent the permeation of water and oxygen because organic materials are highly susceptible to water and oxygen. In particular, high efficiency flexible AMOLEDs needs an extremely low water vapor transition rate (WVTR) of $1{\times}10^{-6}gm^{-2}day^{-1}$. The key factor in high quality inorganic gas barrier formation for achieving the very low WVTR required (under ${\sim}10^{-6}gm^{-2}day^{-1}$) is the suppression of nano-sized defect sites and gas diffusion pathways among the grain boundaries. For formation of high quality single inorganic gas barrier layer, we developed high density nano-structured Al2O3 single gas barrier layer usinga NBAS process. The NBAS process can continuously change crystalline structures from an amorphous phase to a nano- crystalline phase with various grain sizes in a single inorganic thin film. As a result, the water vapor transmission rates (WVTR) of the NBAS processed $Al_2O_3$ gas barrier film have improved order of magnitude compared with that of conventional $Al_2O_3$ layers made by the RF magnetron sputteringprocess under the same sputtering conditions; the WVTR of the NBAS processed $Al_2O_3$ gas barrier film was about $5{\times}10^{-6}g/m^2/day$ by just single layer.

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직장인의 '혼밥' 유지 과정에 대한 질적 연구 (A qualitative study on the process of maintaining the 'eating alone'(honbob) lifestyle)

  • 권혜진;주영아
    • 한국심리학회지 : 문화 및 사회문제
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    • 제24권4호
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    • pp.657-689
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    • 2018
  • 본 연구는 새로운 '혼밥'문화에 대한 중립적인 관점의 이해가 필요하여 직장인들의 '혼밥' 경험과 '혼밥' 유지 과정을 설명하는 실체이론을 개발하고자 하였다. 이를 위해서 서울과 경기지역의 직장에 다니는 직장인이면서 일주일에 전체 식사의 70% 이상 '혼밥'을 하고 5년 이상 '혼밥'을 유지하고 있으며 자발적인 선택으로 '혼밥'을 하고 있는 남녀 10명을 대상으로 심층면접을 실시하였고 수집된 자료는 질적연구 방법 중의 하나인 근거이론방법을 적용하여 자료를 분석하였다. 연구결과, '혼밥'을 유지하는 과정에 대한 패러다임 모형이 도출되었다. '혼밥' 유지 과정에서 인과적 조건은 '조율을 시도하지 않음'으로, 중심현상은 '효율 우선의 욕구를 좇음'으로 드러났다. 맥락적 조건은 '치열한 경쟁 분위기', '조직문화의 약화', '개인주의 문화의 확산'으로, 중재적 조건은 '개인의 성격적 특성과 정서경험', '조직문화 없는 직무특성'으로 나타났다. 중심현상에 대한 참여자의 작용/상호작용 전략은 '내적갈등을 수용하기', '자율적으로 행동하기', '매체를 통해 관계 찾기', '피상적 관계 거리두기'로 나타났다. 결과는 '탐색의 시간을 향유함', '자기돌봄에 충실함', '고독한 편리주의자가 됨', '균형의 필요를 알아차림'으로 드러났다. 핵심범주는 '효율 우선을 따라 자신에게 충실하며 함께함의 중요성을 알아감'으로 밝혀졌다. '혼밥'을 시작하면서 시간효율을 저울질하는 단계, 외부시선에서 자유롭지 못하여 불안한 갈등단계, 자신이 선택한 '혼밥' 행위를 계획하고 합리화하는 조정단계, '혼밥'을 하면서도 '함께함'의 중요성을 알아가는 균형단계를 거치면서 혼밥을 유지하고 있는 것으로 나타났다. 본 연구는 직장인의 '혼밥'경험과 '혼밥' 유지 과정에 대한 통합적 탐색을 토대로 새로운 '혼밥'문화에 대한 이해를 도모하였고 우리 사회가 새로운 '혼밥'문화를 수용하고 다양한 문화의 공존을 인정할 수 있도록 돕고자 하였다.

AZ3l 마그네슘 합금의 고온 크리이프 변형특성에 관한 연구 (A Study on the Creep Deformation Characteristic of AZ31 Mg Alloy at High Temperature)

  • 안정오;강대민;구양;심성보
    • 한국자동차공학회논문집
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    • 제13권3호
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    • pp.186-192
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    • 2005
  • The apparent activation energy Qc, the applied stress exponent n, and rupture life have been determined from creep test results of AZ31 Mg alloy over the temperature range of 200$^{\circ}C$ to 300$^{\circ}C$ and the stress range of 23.42 MPa to 93.59 MPa, respectively, in order to investigate the creep behavior. Constant load creep tests were carried out in the equipment including automatic temperature controller with data acquisition computer. At the temperature of $200^{\circ}C{\sim}220^{\circ}C$ and under the stress level of 62.43~93.59 MPa, and at around the temperature of $280^{\circ}C{\sim}300^{\circ}C$ and under the stress level of 23.42~39.00 MPa, the creep behavior obeyed a simple power-law relating steady state creep rate to applied stress and the activation energy fur the creep deformation was nearly equal to that of the self diffusion of Mg alloy including aluminum From the above results, at the temperature of $200^{\circ}C{\sim}220^{\circ}C$ the creep deformation for AZ31 Mg alloy seemed to be controlled by dislocation climb but controlled by dislocation glide at $280^{\circ}C{\sim}300^{\circ}C$ .And relationship beween rupture time and stress at around the temperature of $200^{\circ}C{\sim}220^{\circ}C$ and under the stress level of 62.43~93.59 MPa, and again at around the temperature of $280^{\circ}C{\sim}300^{\circ}C$ and under the stress level of 23.42~39.00 MPa, respectively, appeard as fullow; log$\sigma$=-0.18(T+460)(logtr+21)+5.92, log$\sigma$ = -0.25(T+460)(logtr+21)+8.02 Also relationship beween rupture time and steady state creep rate appears as follow; ln$\dot$ =-0.881ntr-2.45

2-Hexylthieno[3,2-b]thiophene-substituted Anthracene Derivatives for Organic Field Effect Transistors and Photovoltaic Cells

  • Jo, So-Young;Hur, Jung-A;Kim, Kyung-Hwan;Lee, Tae-Wan;Shin, Ji-Cheol;Hwang, Kyung-Seok;Chin, Byung-Doo;Choi, Dong-Hoon
    • Bulletin of the Korean Chemical Society
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    • 제33권9호
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    • pp.3061-3070
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    • 2012
  • Novel 2-hexylthieno[3,2-b]thiophene-containing conjugated molecules have been synthesized via a reduction reaction using tin chloride in an acidic medium. They exhibited good solubility in common organic solvents and good self-film and crystal-forming properties. The single-crystalline objects were fabricated by a solvent slow diffusion process and then were employed for fabricating field-effect transistors (FETs) along with thinfilm transistors (TFTs). TFTs made of 5 and 6 exhibited carrier mobility as high as 0.10-0.15 $cm^2V^{-1}s^{-1}$. The single-crystal-based FET made of 6 showed 0.70 $cm^2V^{-1}s^{-1}$ which was relatively higher than that of the 5-based FET (${\mu}=0.23cm^2V^{-1}s^{-1}$). In addition, we fabricated organic photovoltaic (OPV) cells with new 2-hexylthieno [3,2-b]thiophene-containing conjugated molecules and methanofullerene [6,6]-phenyl C61-butyric acid methyl ester ($PC_{61}BM$) without thermal annealing. The ternary system for a bulk heterojunction (BHJ) OPV cell was elaborated using $PC_{61}BM$ and two p-type conjugated molecules such as 5 and 7 for modulating the molecular energy levels. As a result, the OPV cell containing 5, 7, and $PC_{61}BM$ had improved results with an open-circuit voltage of 0.90 V, a short-circuit current density of 2.83 $mA/cm^2$, and a fill factor of 0.31, offering an overall power conversion efficiency (PCE) of 0.78%, which was larger than those of the devices made of only molecule 5 (${\eta}$~0.67%) or 7 (${\eta}$~0.46%) with $PC_{61}BM$ under identical weight compositions.

노벨 엔지니어링이 창의적 문제해결력 향상에 미치는 효과 (The Effects of Novel Engineering on Improvement of Creative Problem-Solving Ability)

  • 홍기천;이우진;김세민
    • 산업융합연구
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    • 제18권3호
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    • pp.83-89
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    • 2020
  • 본 논문에서는 창의적 융합 수업 모형인 노벨 엔지니어링 수업이 초등학교 5학년 학생들의 창의적 문제해결력 향상에 미치는 효과에 대해서 기술한다. 이를 위해서 2019년 2학기에 초등학교 5학년 학생 90명을 대상으로 실험 집단과 통제 집단으로 나누어 수업이 진행되었다. 이 수업은 생태계와 상호작용이라는 핵심 개념을 중심으로 총 8차시 모둠별 프로젝트 형식으로 진행되었다. 수업은 5학년 국어, 과학, 실과 과목이 자연스럽게 융합되도록 설계하였으며, 수업 적용 후 사전 사후 창의적 문제해결 검사를 위해서 t-검정이 실시되었다. 실험 결과, 노벨 엔지니어링 수업이 창의적 문제해결력 4가지 하위 요소인 자기 확신 및 독립성, 확산적 사고, 비판적·논리적 사고, 동기적 요소 모두에서 매우 큰 효과가 있다는 것을 알 수 있었다. 노벨 엔지니어링은 이제까지 연구되어왔던 다양한 문제해결력 패러다임을 융합한 수업 모형이다. 이 연구를 통해서 노벨 엔지니어링 수업이 미래를 이끌어 갈 우리 아이들의 다양한 역량을 키울 수 있는 좋은 수업 방법임이 증명되었다. 노벨 엔지니어링이 우리 아이들의 미래 교육을 선도하는 융합 교육과정 모형으로 자리 잡기를 기대한다.

자료포락분석(DEA) 기법을 활용한 도로이동오염원 저감대책의 효율성 분석 (Efficiency Evaluation of Mobile Emission Reduction Countermeasures Using Data Envelopment Analysis Approach)

  • 박관휘;이규진;최기주
    • 대한교통학회지
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    • 제32권2호
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    • pp.93-105
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    • 2014
  • 본 연구는 자료포락분석(Data Envelopment Analysis: DEA) 기법을 활용하여 도로이동오염원 저감대책의 상대적 효율성 평가와 그에 기반하여 우선순위를 결정하였다. 현재 시행 중이거나 장래 계획 가능한 도로이동오염원 저감 대책들을 근거로 실효성 높은 자동차 온실가스와 대기오염물질 저감 대책 10개를 선정하여 시나리오를 구성하였으며, 대기오염물질 4개(CO, HC, NOX, PM), 온실가스 3개($CO_2$, $CH_4$, $N_2O$)물질에 대해 장래 통행패턴을 고려한 교통수요예측모형과 가변적 복합배출계수를 활용하여 2027년도를 최종 목표년도로 저감량을 산정하였다. 저감 대책들 간의 상대적 효율성을 평가하기 위해 DEA모형 중 초효율성 분석을 수행한 결과, 승용차 요일제 참여 확대 대책이 효율성 점수 1.879로 가장 우선순위가 높은 저감대책으로 선정되었으며, 버스전용차로 확대, CNG버스 보급 대책의 효율성이 높은 것으로 분석되었다. 본 연구의 결과는 자동차 온실가스와 대기오염물질 저감대책 우선순위 선정 결정 시 절대적인 자료로 활용될 수는 없지만 저감대책의 방향성을 제시하고 있으므로 향후 자동차 배출량 저감 정책방향 설정 및 체계적인 중장기 저감대책 수립에 기여할 수 있을 것으로 기대된다.

재활치료 환자 보호자의 불안감과 우울감에 대한 향기치료의 효과 (Effects of Aromatherapy on Anxiety and Depression of Caregivers for Patients in Rehabilitation Therapy)

  • 권영문;이상익;김시경;손정우;신철진;최영락
    • 정신신체의학
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    • 제13권1호
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    • pp.24-31
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    • 2005
  • 연구목적: 본 연구는 재활치료 환자를 간병하며 불안감과 우울감을 보이는 보호자에게 향기치료를 적용하여 향기치료 효과에 대한 객관적인 자료를 제공하고자 하였다. 방법: 충북대학교병원 재활의학과에서 물리치료중인 환자 보호자 70명에게 Beck 불안척도와 Beck 우울 척도를 시행하였다. Beck우울 척도상 10점 이상을 보이는 42명을 대상군으로 오렌지 치료군, 라벤더 치료군과 대조군 세군으로 나누어 램프 확산법으로 4주간 향기치료를 하였다. 최종적으로 40명에 대한 향기치료 전후의 Beck불안 척도, Hamilton 불안 평정 척도, Beck 우울 척도, Hamilton 우울 평정 척도, 행복지표 그리고 자아존중감 척도를 평가하였다. 결과: 오렌지 치료군은 대조군에 비해 Beck 우울 척도의 점수 변화에서 유의한 차이를 보였다. 라벤더 치료군은 대조군에 비해 Beck 불안 척도, Beck우울 척도와 행복지표의 점수 변화에서 유의한 차이를 보였다. 결론: 본 연구 결과는 오렌지향유 향기치료는 우울감에, 라벤더향유 향기치료는 불안감과 우울감에 효과가 있음을 시사한다.

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초소성변형의 분자론 (Molecular Theory of Superplastic Deformation)

  • 김창홍;이태규
    • 대한화학회지
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    • 제23권4호
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    • pp.217-236
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    • 1979
  • 소성변형에 대한 著者들의 이론을 초소성합금(Zn-Al eutectoid, A1-Cu, Pb-Sn, Sn-Bi, Mg-Al eutectics)에 적용하였다. 그 결과 초소성합금의 소성변형은 두 개의 grain boundary流動單位의 平行連結로 나타낼 수 있었다. 이 두 개의 流動單位는 流動式에 나타나는 parameter $X_{gj}/{\alpha}_{gj}$${\beta}_{gj}$(j=1 혹온 2)로 表現할 수 있으며 이들을 實驗的으로 求할 수 있었다. 著者들의 流動式은 實驗과 잘 一致하였다. Strain rate sensitivity 對 -In(strain rate) 곡선을 이론으로 구한 결과 유동단위수만큼의 peak가 ${\beta}_{gj}$(j=1 or 2) 값에 따라 분리되어 나타났고 초소성의 조건도 ${beta}_{gj}$값에 의하여 결정됨을 알았다. ${\beta}_{gj}값의 粒子크기 依存性을 구하였고 온도변화에 따른 ${\beta}_{gj}$값 변화로부터 각 流動單位의 활성화엔탈피, ${\Delta}H_{gj}^{\neq}$도 구하였다. 그 결과 ${\Delta}H_{gj}^{\neq}$는 재료성분원소들의 grain boundary 자체확산에 의한 활성화엔탈피와 같이 나타났고 또 이들은 粒子 크기 증가에 마라 증가함을 보였다

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A Study on the Effect of the Use of Mobile Office Systems on Work-Life Balance

  • Cho, Namjae;Lee, Hyungju
    • Journal of Information Technology Applications and Management
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    • 제20권1호
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    • pp.43-51
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    • 2013
  • Human being does work to live out and they have their private life because human has sociality. Both work and life are important to live out but they are on the trade-off relationship. Because keeping the balance between work and life is too hard, it has been interested by academic and practical areas. Definition of Work-life balance here is that balance or imbalance arising between work and life has no negative impact on their daily life. Above all, Work-life balance is important because it is strongly related to identity. Recently, the introduction of the mobile office system has emerged as a way to solve the problem of work-life balance. It is based on the teleworking which was formerly generated. Teleworking is to perform the work in the employee's home or office space set aside without going into the workplace. Concept of the mobile office system here is not only using portable devices during work for convenience but also the system which is designed for the performance. Thanks to the diffusion of smart devices(smart phone, tablet pc), mobile office system has been spread. Although the importance of mobile office systems is emerging, there are few researches about it. Even they mostly focus on the standpoint of performance of mobile office system. However, Quality of life is as important as the performance. As a part of Quality of Life field, Work-life balance is the closest to employee's quality of life. So this study aims to examine the effect of the use of mobile office systems on work-life balance. To do so, we try to find factors effecting Work-life balance from existing studies and then set a research model. We set the use of mobile office systems as independent variables which are divided by use of function, use by location and use by situation. There are four dependent variables - sense of self command, sense of balance, solving work problem, solving life problem. We collected data from employees who are using mobile office systems on their job. 215 people were participated in the survey and we used multiple regression analysis to verify our research model. Results show that every independent variable has no impact on solving work problem while they have slight impact on the other dependent variables. Especially use on the business trip has significant effect on dependent variables. It means that there is a possibility use of mobile office system could control the employee's quality of life and system should be evolved until it covers even critical tasks. Also, support for mobile office system -education, encouragement-should be provided. By mobile office system is maturing, future research would be done.

친환경농업정책 분야의 거버넌스 체계 구축방안 (Schemes for Constructing the System of Environmentally Friendly Agri-policy Governance)

  • 김호;허승욱
    • 한국유기농업학회지
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    • 제14권2호
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    • pp.159-177
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    • 2006
  • Governance systems are basically an autonomous cooperation type among the government, civil society and market, also a new paradigm for efficient and democratic administration of policies. The governance mainly consists of the central operating body, institutions, operating principles and so on. The constituents are the nation(government), civil society(NGO) and market(firm). Institutional conditions are a legitimate base, financial stability and independency. And as a operating principle, governance systems have common goals and issues from a national and social point of view. This governance has been recently emerged due to financial risk of government, diffusion of new liberalism going with the globalization, localization-decentralization, and development of civil society and information-oriented society. We have to grope fur the framework of participatory agri- policy confronting globalization and localization as well as developing our agriculture and rural village. This agri-policy governance should be theoretically focused on policy network or self-organizing network or multi-lateral governance (MLG) based on NPM. Also, it is proper to have connection of nation-central type and civil society-central type. And it is necessary to have a MLG type with local governance corresponding to localization and decentralization. Governance should have the type whose participants have authority and responsibility as well. Basic directions of environmentally friendly agri-policy governance are as follows : first, its purposes are constructing the democratic and efficient framework of participatory environmentally friendly agri-policy based on consensus of all the related groups, embodying environmentally friendly agri-policy adjusted to local field, raising farmer's real interest, and improving their position. Second, its form should have a council or an agreement system, not an advisory or a consultation organ. Thus, public sector(eg. government) and voluntary sector(eg. farmers' organization) jointly execute agricultural policy and are responsible together. Environmentally friendly agri-policy governance is mainly made up of farmers' organization, cooperative and civil society(NGO). And secondary bodies are agribusinesses and academic groups. Government interacts with the main bodies on administrative execution. And environmentally friendly agri-policy governance has MLG type with a central unit, province and county units. Environmentally friendly agri-policy governance has several main functions such as agri-policy partnership, speaking for farmer's rights and interests, investigation and research on domestic and foreign agricultural streams, and etc. Especially, local unit will play roles in activation for regional agriculture, consulting on technique and management, education and training services, services entrusted by government, and so on.

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