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1
Design of a multi-channel polarization-preserving optical system for the KSTAR motional Stark effect diagnostic

Lee, Kyuhang,Ko, Jinseok,Jo, Jae Heung,Chung, Jinil Elsevier 2017 Fusion engineering and design Vol.121 No.-
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Abstract An optical system capable of preserving, or minimizing the change of, the polarization properties of incident light has been designed and fabricated for the motional Stark effect diagnostic system which measures internal magnetic field structures inside the tokamak for the Korea Superconducting Tokamak Advanced Research. A dual photoelastic modulator (PEM) with a linear polarizer is included in the optical train with four lenses, a mirror and a dichroic beam splitter. Particular cares have been taken for the polarization properties of the delivered light to be perturbed as little as possible under a strong magnetic field and high vacuum. The lenses are made of STIH-6, a material with low Verdet constant, which minimizes the Faraday rotation. The residual Faraday rotation that takes place in the non-STIH-6 optical elements such as the vacuum window and the optical apertures of the PEM is calibrated out from the in-situ measurements using an in-vessel reference polarizer while energizing the magnetic field coils. In the lens design, the object plane is rotated by 44.8° from the optical axis because of the tilted setup-port. The image surface has a finite curvature to reduce the aberration from the four lenses. The fiber dissector is designed based on the focal plane that aligns the focal points from 25 lines-of-sight, each of which constitutes a bundle of 19 fibers. The fibers run about 35m from the front optics in the tokamak vacuum vessel to the detector in the diagnostic area remote from the tokamak hall. The footprint images at the intersections of the lines-of-sight on the neutral beam trajectory confirms the imaging quality is sufficient to the diagnostic requirement with the designed magnifications. Highlights <UL> <LI> Description on how the polarization control is accomplished in the complex optics for the KSTAR MSE system. </LI> <LI> Various quantitative analyses for the optical performance in accommodating multiple and tilted observation chords. </LI> <LI> Integration of the fabricated components including the fiber bundles and the dissector module for them. In-vessel testing for the image formation with the integrated optics system. </LI> </UL>
2
경제성숙단계에서의 소농의 재인식

최식인(Sik-in Choi) 한국경제발전학회 2006 經濟發展硏究 Vol.12 No.1
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- 복사/대출신청
개방 이후, 농업의 피해가 현실로 나타나고 있고 이에 따라 농촌에는 다양한 변화가 초래되고 있다. 개방은 불가피한 것이지만 개방에 의해 농업기반이 붕괴되는 것은 바람직하지 않다. 농업은 식량공급이라는 기능이외에도 국가적으로 필요한 기본적 가치를 제공해 주는 기능이 있기 때문에 유지되어야 할 필요성이 있다. 이러한 농업의 기본적 가치는 농업이 소규모 경영으로 이루어질 때 잘 나타날 수 있다. 그런데 개방 이후 소농구조에 있어서 근본적인 변화가 초래되고 있다. 이글은 바람직한 소농구조를 유지하기 위한 방안으로서 농업정책이 농업발전과 농업보전정책으로 이원화되어야 하고 특히 농업보전정책이 더욱 중요하다는 것을 강조한다.(JEL : 02, R0, Q1) This study investigates structural changes of the Korea"s peasantry. It also identifies crises of the country"s rural peasant communities under the economic opening system. Korean peasantry has been deteriorated in population structure, arable land size, and income composition. Analysis on these changes suggests that the traditional peasant communities are exposed to collapse and this unwanted disaster could result in serious adversities to the national economy. The various functions of rural community include: labor absorption, conservation of rural landscapes, and preservation of traditional cultures. But these roles could not be viable without production activities of peasant. Therefore, in order to sustain the country"s peasant communities this study proposes preservation policies for small scale farming households and also administrative preparations of multi-dimensional approaches leading to successful rural planning.
3
Influence of porosity and cement grade on concrete mechanical properties

Huang, Jiandong,Alyousef, Rayed,Suhatril, Meldi,Baharom, Shahrizan,Alabduljabbar, Hisham,Alaskar, Abdulaziz,Assilzadeh, Hamid Techno-Press 2020 Advances in concrete construction Vol.10 No.5
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The given research focuses on examining the effect of relatively humidity (RH) and curing temperature on the hydrates as well as the porosity of calcium sulfoaluminate (CSA) cement pastes. Numerous tests, which consist of mercury intrusion porosimetry (MIP), thermosgravi metric (TG) and X-ray diffraction (XRD) were conducted. Various characterization techniques which include, scanning electron microscopy, Fourier transform microscopy along with X-ray diffraction evaluations were conducted on the samples to examine phase formation and crystallinity, morphology and microstructure along with bond formations and functional groups, respectively. During long-term study, the performance of concrete which consisted of limestone and flash-calcined was close to those from standard Portland cement concrete. Traditional classifications and methods of corrosion were widely used for the assessment of steel in concrete which may get employed to concrete which contains LC3 to recalibrate the range of polarization resistance for passitivity condition. For example, there is up to 79.5% and 146% respective flexural and compressive strengths. Moreover, they developed more advance electrical and thermo-mechanical performance with a substantial reduction in absorption of water of close to 400%. These advantages allow this research crucial to evaluate how these methods can be applied. Additionally, the research evaluates developed and more advanced cement preservation and repair techniques. The conclusion suggests concerted efforts by various stakeholders such as policy makers to enable low-carbon rates.