• 제목/요약/키워드: Long Gap

검색결과 604건 처리시간 0.023초

Synthesis and Photovoltaic Properties of Polymers Based on Cyclopentadithiophene and Benzimidazole Units

  • Song, Su-Hee;Park, Sei-Jung;Kwon, Soon-Cheol;Shim, Joo-Young;Jin, Young-Eup;Park, Sung-Heum;Kim, Il;Lee, Kwang-Hee;Suh, Hong-Suk
    • Bulletin of the Korean Chemical Society
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    • 제33권6호
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    • pp.1861-1866
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    • 2012
  • The new semiconducting copolymers with 4,4-dialkyl-$4H$-cyclopenta[2,1-$b$:3,4-$b^{\prime}$]dithiophene and 2,2-dimethyl-$2H$-benzimidazole units were synthesized. The fused aromatic rings, such as cyclopentadithiophene (CPDT) unit, can make the polymer backbone more rigid and coplanar, which induces long conjugation length, narrow band gap, and strong intermolecular ${\pi}-{\pi}$ interaction. The stacking ability was controlled through attaching of linear or branched alkyl side chains. The spectra of PEHCPDTMBI and PHCPDTMBI in the solid films show absorption bands with maximum peaks at 401, 759 and 407, 768 nm, and the absorption onsets at 925 and 954 nm, corresponding to band gaps of 1.34 and 1.30 eV, respectively. The devices comprising PHCPDTMBI with $TiO_X$ showed a $V_{OC}$ of 0.39 V, a $J_{SC}$ of 1.14 $mA/cm^2$, and a $FF$ of 0.34, giving a power conversion efficiency of 0.15%. The PHCPDTMBI with linear alkyl chain on CPDT shows good solubility in organic solvent with higher PCE value than that of PEHCPDTMBI.

The Effect of R&D on High-Tech Product Export Competitiveness: Empirical Evidence from Panel Data of East Asian Economies

  • Alemu, Aye Mengistu
    • STI Policy Review
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    • 제3권1호
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    • pp.46-62
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    • 2012
  • This study investigates the effects of the two most important indicators of a nation's state of scientific infrastructure: R&D investment and the number of R&D researchers engaged in high-tech product export competitiveness for a panel of 11 countries/economies from East Asia from 1994 to 2010. A GMM panel estimation method was employed to account for the dynamic effect of trade and to control for un-observed country specific effects that may arise due to an inter-country differences and intra-country dynamics. Accordingly, the empirical results reveal that (once controlled for the influence of per capita income) physical capital and infrastructure, a 1% increase in a country's expenditure on the ratio of R&D to GDP may increase high-tech product export performance by approximately $397 million per year. Other factors constant, a 1% increase in the number of R&D researchers is expected to increase the ability to export high-tech products by approximately $67 million. The East Asian development experience demonstrates how latecomers can follow systematic industrialization and join the handful of economies that have come a long way toward closing the knowledge gap with the global technological leaders. However, this does not mean that the policy approaches and overall commitments pursued by each East Asian economy in relation to R&D investment and acquisition of an adequate pool of researchers, and their ultimate achievements in high-tech product export competitiveness were uniform. As a result, there is still a significant variation among countries/economies in terms of performance. This study recommended a number of potential tools and policy instruments that may assist policy makers to foster R&D as an engine to enhance the high-tech product export competitiveness.

스웨덴 훼르셸 생태마을의 주민참여 실태에 관한 사례연구 (A Case Study on Residents' Involvement in Sk$\"{a}$rk$\"{a}$ll Ecovillage in Sweden)

  • 최정신
    • 가정과삶의질연구
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    • 제28권6호
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    • pp.19-34
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    • 2010
  • This study aims to describe actual condition of residents' involvement of Sk$\"{a}$rk$\"{a}$ll ecovillage in Sweden by in-depth interviews with five residents. This study, hopefully, could contribute to offer useful information for forming ecovillage, as well as awakening about ecovillage movement to the public in Korea. The interviews were fulfilled during spring of 2010 in G$\"{o}$teborg and Sk$\"{a}$rk$\"{a}$ll ecovillage in Sweden. The results are as follows: 1) In terms of overall residents' involvement by self-evaluation everybody agrees with that residents' involvement was quite excellent during forming stage of the village, while it has been notably decreased now in running stage. It reveals there is a gap between ideology and reality. 2) Concerning decision making method, they use majority decision instead of consensus, since only 9 households of 20 are residing there all year around, it is hardly possible to assemble all the residents in the meeting. In Accordance with problematic conflicts in the village recently, development of socialization with others and education of communication skill for residents probably could be helpful to resolve conflicts among residents in long term. 3) In terms of evaluation of ecovillage movement in Sk$\"{a}$rk$\"{a}$ll ecovillage, it is the fact that many residents live less self-sufficiently, more energy consumed than the ideology pursuits. Also, they live with close connections with conventional society. Nevertheless, the efforts they are willing to practice 3R principles (Recycle, Reuse, Reduction) have to be highly respected, if we consider its educational influence to environmental movement for the conventional society.

A Study on Electro-optical Characteristics in Three Kinds of Liquid Crystal Display Operating Mode

  • Moon, Hyun-Chan;Bae, Yu-Han;Hwang, Jeoung-Yeon;Seo, Oae-Shik
    • Transactions on Electrical and Electronic Materials
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    • 제6권2호
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    • pp.73-77
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    • 2005
  • In this study, we investigated response characteristics of liquid crystal display (LCD) with different operating mode of nematic liquid crystals (NLCs) such as 45 $^{circ} twisted nematic (TN), 67.3 $^{circ} TN and electrical controlled birefringence (ECB) on the rubbed polyimide (PI) surface with side chains. The pretilt angles generated on polyimide surfaces of the three kinds of LCD operating modes were about 12 $^{circ} that was higher than those of conventional TN-LCOs. Also, the Electro-optical (EO) performance of these LCOs showed stable condition. Low transmittance of the 45 $^{circ} TN and 67.3 $^{circ} TN cell on the rubbed PI surface were measured by using low cell gap d. The fast response time in ECB cell among the three kinds of LCD operating modes was achieved. Also, thermal ability of fast 90 $^{circ} TN-LCD was investigated. The threshold voltage and the response time of thermal stressed TN-LCOs showed the same performances on no thermal stressed TN-LCOs. There was little change of value in these TN cells. However, the transmittances of TN-LCOs on the rubbed PI surface decreased while increasing thermal stress time. Therefore, the thermal stability of TN-LCD was decreased by the high thermal stress for the long duration.

작은 탄성 변형률 하의 고정-자유 지지된 스트립과 보의 변형 (Deformations of Cantilever Strips and Beam with Small Elastic Strains)

  • 호광수;박기철;임세영
    • 대한기계학회논문집
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    • 제13권4호
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    • pp.572-582
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    • 1989
  • 본 논문에서는 윗면에 균일한 압력을 받는 외팔보의 굽힘 변형과 고정 자유 지지된 무한길이 스트립의 폭 방향 굽힘변형을 위에 언급된 이론을 적용하여 살펴보고자 한다. 먼저 기본 지배방정식들을 요약하여 변형률의 1차항까지 나타내며 각 경우에 대해 변형을 중심선에 상대적인 단면의 변위와 단면의 회전 그리고 병진을 나타내며 각 경우에 대해 변형을 중심선에 상대적인 단면의 변위와 단면의 회전 그리고 병진을 나타내는 도심의 변위로 분해하고 도심에 상대적인 변위는 Michell에 의한 평판의 해와 St. Venant에 의한 봉의 해를 이용한다. 가정된 변위장으로부터 응력을 구한 다음 적절한 조건 하에서 국부평형방정식을 구하여 전체평형방정식을 유도한다. 또한 이로부터 각 단면의 회전과 중심선의 변위가 구해질 수 있음을 보인다.

핵융합 촉진 방법을 이용한 새로운 핵융합 장치의 개발 (Development of the New nuclear fusion devices Using Method of promoting nuclear fusion)

  • 김기성
    • 한국조명전기설비학회:학술대회논문집
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    • 한국조명전기설비학회 2005년도 학술대회 논문집
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    • pp.151-155
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    • 2005
  • 지금까지의 핵융합 장치는 자기우물과 열역학을 바탕으로 한 토카막 장치가 수소핵융합을 하였으나 고온의 플라스마를 장시간 동안 가둠이란 현실적으로 불가능하여 성공사례가 없었다. 본 핵융합 촉진 방법을 이용한 새로운 핵융합 장치는 토카막 장치의 토로이달 자기장용 알루미늄코일 내에 토러스 철심 C형 Core Block과 토로이달 알루미늄코일을 넣어 토로이달 자기장을 모으고 토로이달 전류 흐르도록 하여 토러스 Core의 일부가 절개된 간극사이에 핵융합로를 배치하고 융합원료(전해액)를 토로이달 전류로 전기분해 한다. 전원과 토로이달 자계용 코일, 토로이달 코일 융합원료로 직렬회로로 이루어져 있어 토로이달 전류는 필라멘트 전류로 되어 융합원료에 투입된다. 필라멘트 전류사이에는 자기흡입력이 외부의 입력전력으로 계속 증대되어 쿨롱에 힘을 넘어 핵융합에 이르고 그로인해 질량결손이 생겨 아인슈타인의 질량에너지$(E=mC^2)$가 빛에너지와 열에너지로 방출됨을 확인했다.

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$SF_{6}$가스와 절연지의 절연계에서 가스압력에 따른 부분방전 현상(II) (Partial Discharge Phenomena with $SF_{6}$ Gas Pressures in Insulation Consisted of Insulation Paper and $SF_{6}$ Gas(II))

  • 선종호;김광화;박정후;조정수
    • 대한전기학회논문지:전기물성ㆍ응용부문C
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    • 제51권9호
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    • pp.430-435
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    • 2002
  • The $SF_{6}$ gas insulated power equipments have the insulation systems which are composed of $SF_{6}$ gas and insulation paper. It is repored that their insulation abilities are influenced by the $SF_{6}$ gas gaps in those insulation systems and gas pressures. This paper describes partial discharge phenomena with $SF_{6}$ gas pressures in insulation system of $SF_{6}$ gas-insulation paper Specimens of $SF_{6}$ gas-insulation paper were prepared and aramid paper was used as insulation paper. Partial discharge inception voltages(PDIV) and breakdown voltages for the existence of $SF_{6}$ gas gaps were measured by short term tests with gas pressures. Also, average PD quantities and pulse counts, life times of each specimens were calculated from the results of long term aging tests with gas pressures. It was found that the $SF_{6}$ gas gaps decrease increasing rates of PDIV and brealdown voltages according to gas pressure increase and the insulation breakdown caused by the smaller PD quantities than 1[pC] at the high gas pressure of 300kPa is due to the increase of energy density with increase of gas pressure.

근사알고리즘을 적용한 금형온도 제어 방법 (Mold temperature control method using Approximation Algorithm)

  • 박성수;구형일
    • 한국정보통신학회:학술대회논문집
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    • 한국정보통신학회 2017년도 추계학술대회
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    • pp.270-273
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    • 2017
  • 플라스틱 사출물의 불량 감소 및 사이클 타임 축소를 통한 생산성 향상은 사출업계의 오랜 숙원 사항이다. 특히 중국 등 후발 주자의 추격과 좁혀지지 않는 독일, 일본과의 기술격차 사이에 끼어 있는 국내 사출업계에게 생산성 향상은 매우 절실하다. 30여년 국내 사출업계의 연구와 경험을 통해 금형 내 사출물 표면 온도 제어가 품질 관리의 핵심임을 알게 되었고 PID 제어 등 고급제어 기법을 활용한 다양한 시도가 있었으나 독일, 일본의 유수 업체의 생산성에는 아직 부족하다. 이에 근사알고리즘 중 "Knapsack"개념과 "Minimum Makespan Scheduling"기법을 활용하여 PID 제어로 풀기 어려운 수렴하지 않고 주기적인 반복 데이터 패턴을 지닌 대상을 효율적으로 제어할 수 있는 방법을 소개하고 또한 실제 사출 현장에서 추출한 데이터 분석으로 사출품의 생산성 향상에 근사알고리즘을 이용한 제어가 충분히 효과적임을 제시하고자 한다.

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평등전계에서 SF6/CF4 혼합가스의 AC절연내력 특성 (AC Breakdown Voltage Characteristics of SF6/CF4 in Uniform field)

  • 황청호;박신우;김남렬;허창수
    • 한국전기전자재료학회논문지
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    • 제20권4호
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    • pp.381-387
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    • 2007
  • The excellent dielectric properties of $SF_6$(sulfur hexafluoride) have lead to its wide range of application in the field of high voltage insulation. Because there has been some recent concern regarding the environmental impacts of $SF_6$ binary gas mixtures, with $SF_6$ as the main component, have been the subject of active research. Scientists have long been interested in the possible use of gaseous fluorocarbons, including $CF_4$ (Carton Tetrafluoride), in high voltage applications due to their inert character and high dielectric strength. This paper presents experimental results concerning the AC breakdown characteristics lot various mixtures of $SF_6/CF_4$ in a test chamber and 25.8 kV GIS (Gas Insulation Switchgear) at practical pressures (0.1-04 MPa) and gap lengths (0.5 mm, 1 mm) in a test chamber. In the result, it was observed that an increase in the dielectric strength is attained through the addition of $SF_6$ to $CF_4$. It is possible to make an environment friendly gas insulation material while maintaining the dielectric strength by combing $SF_6$ and $CF_4$ which generates a lower level of the "global warming" effect.

A depth-based Multi-view Super-Resolution Method Using Image Fusion and Blind Deblurring

  • Fan, Jun;Zeng, Xiangrong;Huangpeng, Qizi;Liu, Yan;Long, Xin;Feng, Jing;Zhou, Jinglun
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • 제10권10호
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    • pp.5129-5152
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    • 2016
  • Multi-view super-resolution (MVSR) aims to estimate a high-resolution (HR) image from a set of low-resolution (LR) images that are captured from different viewpoints (typically by different cameras). MVSR is usually applied in camera array imaging. Given that MVSR is an ill-posed problem and is typically computationally costly, we super-resolve multi-view LR images of the original scene via image fusion (IF) and blind deblurring (BD). First, we reformulate the MVSR problem into two easier problems: an IF problem and a BD problem. We further solve the IF problem on the premise of calculating the depth map of the desired image ahead, and then solve the BD problem, in which the optimization problems with respect to the desired image and with respect to the unknown blur are efficiently addressed by the alternating direction method of multipliers (ADMM). Our approach bridges the gap between MVSR and BD, taking advantages of existing BD methods to address MVSR. Thus, this approach is appropriate for camera array imaging because the blur kernel is typically unknown in practice. Corresponding experimental results using real and synthetic images demonstrate the effectiveness of the proposed method.