• Journal of the Korean institute of surface engineering
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• v.50 no.5
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• pp.315-321
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• 2017

Antireflective pyramid arrays can be readily obtained via anisotropic etching in alkaline solution (KOH, NaOH), which is widely used in crystalline-Si (c-Si) solar cells. The periodic inverted pyramid arrays show even lower light reflectivity because of their superior light-trapping characteristics. Since this inverted pyramidal structures are mostly achieved using very complex techniques such as photolithograpy and laser processes requiring extra costs, here, we demonstrate the Cu-nanoparticle assisted chemical etching processes to make the inverted pyramidal arrays without the need of photolithography. We have mainly controlled the concentration of $Cu(NO_3)_2$, HF, $H_2O_2$ and temperature as well as time factors that affecting the reaction. Optimal inverted pyramid structure was obtained through reaction parameters control. The reflectance of inverted pyramid arrays showed < 10% over 400 to 1100 nm wavelength range while showing 15~20% in random pyramid arrays.

• Current Photovoltaic Research
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• v.6 no.3
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• pp.86-90
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• 2018

To generate more current in crystalline silicon solar cells, surface texturing is adopted by reducing the surface reflection. Conventionally, random pyramid texturing by the wet chemical process is used for surface texturing in crystalline silicon solar cell. To achieve higher efficiency of solar cells, well ordered inverted pyramid texturing was introduced. Although its complicated process, superior properties such as lower reflectance and recombination velocity can be achieved by optimizing the process. In this study, we investigated optical and passivation properties of inverted pyramid texture. Lifetime, implied-Voc and reflectance were measured with different width and size of the texture. Also, effects of chemical rounding at the valley of the pyramid were observed.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.26 no.11
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• pp.841-845
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• 2013

We give a textured front on silicon wafer for high-efficiency solar cells by using micro contact printing method which uses PDMS (polydimethylsiloxane) silicon rubber as a stamp and SAM (self assembled monolayer)s as an ink. A random pyramidal texturing have been widely used for a front-surface texturing in low cost manufacturing line although the cell with random pyramids on front surface shows relatively low efficiency than the cell with inverted pyramids patterned by normal optical lithography. In the past two decades, the micro contact printing has been intensively studied in nano technology field for high resolution patterns on silicon wafer. However, this promising printing technique has surprisingly never applied so far to silicon based solar cell industry despite their simplicity of process and attractive aspects in terms of cost competitiveness. We employ a MHA (16-mercaptohexadecanoic acid) as an ink for Au deposited $SiO_2/Si$ substrate. The $SiO_2$ pattern which is same as the pattern printed by SAM ink on Au surface and later acts as a hard resist for anisotropic silicon etching was made by HF solution, and then inverted pyramidal pattern is formed after anisotropic wet etching. We compare three textured surface with different morphology (random texture, random pyramids and inverted pyramids) and then different geometry of inverted pyramid arrays in terms of reflectivity.

• Korean Journal of Plant Resources
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• v.12 no.2
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• pp.133-138
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• 1999

The structure of shoot apex in zygotic and somatic embryos of Daucus carota L. cv. Hongshim was observed by using SEM and longitudinal sections. Shoot apex of zygotic embryo was of an inverted boat shape, and these of two, three and four cotyledon somatic embryos were of an inverted boat shape, a pyramid shape and a convex diamond shape, respectively. In zygotic embryo shoot apex is consisted of small cells which are arranged in layers (tunica) and show corpus in central region. In somatic embryos shoot apices are consisted of somewhat large cells which are arranged in irregularly or slight regularly.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.473-476
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• 2006

Microcavity plasma devices having characteristic dimensions below $100\;{\mu}m$ have been investigated as a candidate for the next generation of plasma displays. Arrays of inverted pyramid microcavity devices, fabricated in Si with emitting apertures of $(50\;{\mu}m)^2$ and designed for AC or bipolar excitation, demonstrate a luminous efficacy above 6 lm/W at pressures up to and beyond one atmosphere of Ne/Xe mixtures. Also the design of analogous microplasma devices in ceramic multilayer structures or plastic substrates is disccussed.

• International Journal of Concrete Structures and Materials
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• v.11 no.1
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• pp.161-169
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• 2017

Flat slab systems are vastly used in multi-story buildings because of their savings in story height and construction time, as well as for their flexibility in architectural remodeling. However, they frequently suffer brittle punching-shear failure around columns, especially when subjected to lateral loads. Therefore, seismic codes labeled flat slabs as non-ductile systems. This research goal is investigating some construction alternatives to enhance flat slab ductility and deformability. The alternatives are: adding different types of punching-shear reinforcement, using discreet fibers in concrete mixes, and increasing thickness of slab around columns. The experimental study included preparation and testing of seven half-scale interior slab-column connections up to failure. The first specimen is considered a reference, the second two specimens made of concrete mixes with different volumetric ratios of polymer fibers. Another three specimens reinforced with different types of punching-shear reinforcement, and the last specimen constructed with drop panel of inverted pyramidal shape. It is found that using the inverted pyramid-shape drop panel of specimen, increases the punching-shear capacity, and the initial and the post-cracking stiffnesses. The initial elastic stiffnesses are different for all specimens especially for the slab with closed stirrups where it is experienced the highest initial stiffness compared to the reference slab.

• Journal of Haehwa Medicine
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• v.11 no.1
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• pp.217-235
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• 2002

NSAIDs(Non-steroidal anti-inflammatory drug), Steroid(corticosteroid), DMARD(Dise modifying anti-rheumatic drug), Immunosuppressive agent, BRM(Biologic response modifier) western medication of Rheumatoid arthritis. Recent trends in western medication of Rheum arthritis is an inverted pyramid treatment. Byunjeungsichi(辨證施治), Yakchim(藥針), Oechibub(外治法 external treatment) are orie medication of Rheumatoid arthritis. Yakchim(藥針) and Oechibub(外治法 external treatment) the advantage of trouble in oral administration.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.10a
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• pp.665-668
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• 2012

This paper describes research results that 2-D contents, which display in smart phone or tablet PC to be able to see the 3-D stereoscopic by use projection technique. For this research, we have construct four brown-glass into pyramid shape, project each of the four LCD monitors that output from the PC screen into of the four inverted pyramid-shaped mirror and display the 3-D image to the center of the mirror system. For the test, We use tablet PC and server PC(desktop PC) connected by wireless network, tablet PC select contents which is displayed in the server PC, and displayed selected contents into the 3-D image to the center of the mirror system. Through the test, we have showed that it is possible to display 3-D stereoscopic to the 2-D contents by use projection technique. Although, display image is depending on the observer's viewing angle.

• Journal of Internet Computing and Services
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• v.18 no.2
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• pp.105-111
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• 2017

This paper explores the characteristics of curated news content. With content analysis of 1020 news clips, the study found that news values immersed in card news differed from those of traditional news. Specifically, timeliness was not regarded as a key factor in newsworthiness. Rather, information and social impacts were highly emphasized. Considering news consumers depend on traditional news for timely news, curated news content was not a replacement for traditional news but a supplement. By refurbishing photos from previous news reports and googling the web for related information, curated news reiterates social meaning and provides relevant information. Furthermore, salience of human interest can be explained by entertaining characteristics of curated news. In story forms, the list technique has several important points to stress, and was more frequently used than inverted pyramids. Another key finding of this study is man-on-the street as the most quoted main sources in the curatorial context.

• Journal of Korean Society of Rural Planning
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• v.25 no.4
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• pp.99-107
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• 2019

This paper analyzed the characteristics of population change from 2000 to 2018 in 466 mountainous areas using resident registration data from the Ministry of the Interior and Safety, and projected the population in those areas through 2050 with the cohort change ratio method. The population had dramatically decreased from 2000 to 2009. With the slowing population decrease after 2010, the population has increased gradually since 2014. Especially the population of ages over 65 in 2018 had increased 34% compared to 2000, while the working age population had decreased 29%. This shows that population aging becomes serious problems in the mountainous area. Assuming the cohort change ratios from 2010 to 2015 and child-woman ratio in 2015 remain constant, it appeared that the projected population of the mountainous area dropped to 1.26 million in 2030 and 820,000 in 2050. It is expected to have a population with an inverted pyramid structure showing a gender imbalance with more females in 60's and 70's. Although it continues to show the recent population growth in mountainous area, population in mountainous area is expected to consistently decrease. Therefore, it is required to develop policies and strategies to promote an influx of people into mountainous area for maintaining functionality and sustainability of mountainous areas.