• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.192-193
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• 2007

An evaporated Ti/Pd/Ag contact system is most widely used to make high-efficiency silicon solar cells, however, the system is not cost effective due to expensive materials and vacuum techniques. Commercial solar cells with screen-printed contacts formed by using Ag paste suffer from a low fill factor and a high shading loss because of high contact resistance and low aspect ratio. Low-cost Ni and Cu metal contacts have been formed by using electro less plating and electroplating techniques to replace the Ti/Pd/Ag and screen-printed Ag contacts. Ni/Cu alloy is plated on a silicon substrate by electro-deposition of the alloy from an acetate electrolyte solution, and nickel-silicide formation at the interface between the silicon and the nickel enhances stability and reduces the contact resistance. It was, therefore, found that nickel-silicide was suitable for high-efficiency solar cell applications. Cu was electroplated on the Ni layer by using a light induced plating method. The Cu electroplating solution was made up of a commercially available acid sulfate bath and additives to reduce the stress of the copper layer. In this paper, we investigated low-cost Ni/Cu contact formation by electro less and electroplating for crystalline silicon solar cells.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.23 no.7
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• pp.575-579
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• 2010

The technologies of Ni/Cu plating contact is attributed to the reduced series resistance caused by a better contact conductivity of Ni with Si and the subsequent electroplating of Cu on Ni. The ability to pattern narrower grid lines for reduced light shading was combined with the lower resistance of a metal silicide contact and an improved conductivity of the plated deposit. This improves the FF (fill factor) as the series resistance is reduced. This is very much requried in the case of low concentrator solar cells in which the series resistance is one of the important and dominant parameter that affect the cell performance. A Selective emitter structure with highly dopeds regions underneath the metal contacts, is widely known to be one of the most promising high-efficiency solution in solar cell processing In this paper the formation of a selective emitter, and the nickel silicide seed layer at the front side metallization of silicon cells is considered. After generating the nickel seed layer the contacts were thickened by Cu LIP (light induced plating) and by the formation of a plated Ni/Cu two step metallization on front contacts. In fabricating a Ni/Cu plating metallization cell with a selective emitter structure it has been shown that the cell efficiency can be increased by at least 0.2%.

• Applied Chemistry for Engineering
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• v.20 no.1
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• pp.99-103
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• 2009

HBr and $O_2$ in $Cl_2$ gas ambient for the high density plasma gate etching has been used to increase the performance of gate electrode in semiconductor devices. When an un-doped amorphous silicon layer was used for a gate electrode material, the notching profile was observed at the outer sidewall foot of the outermost line. This phenomenon can be explained by the electron shading effect: i.e., electrons are captured at the photoresist sidewall while ions pass through the photoresist sidewall and reach the oxide surface at a narrowly spaced pattern during the over etch step. The potential distribution between gate lines deflects the ions trajectory toward the gate sidewall. In this study, an appropriate mechanism was proposed to explain the occurrence of notching in the gate electrode of un-doped amorphous silicon.

• Proceedings of the SAREK Conference
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• 2008.06a
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• pp.906-911
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• 2008

Because the perimeter of buildings is strongly influenced by solar and the outdoor air temperature, the area has different environmental properties compared to the interior of a building, as in summer heat gain, and in winter heat loss. In particular, if the external wall is glass, the characteristics of the glass material make it pervious to outside conditions, thereby making big changes to the thermal environment. By combining shading device and the efficient exhaust system, an energy saving can be achieved compared to no air barrier systems. The simplified air barrier system is developed with the idea that energy could be conserved by carefully and effectively blowing out the air caught between the glass surface and the roller blind. The way it is configured is therefore by making the roller blind's air-path, and by placing the air output ducts in the most optimum positions. This simplified air barrier system will give improvement in the thermal environment of the parameter area that is strongly affected by solar and the outdoor condition.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.210-211
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• 2007

Amid booming PV(photovoltaic) industry, BIPV(Building Integrated PV) is one of the best fascinating PV application technologies. To apply PV in building, variable factors should be reflected such as installation position, shading, temperature effect and so on. Especially a temperature should be considered, for it affects both electrical efficiency of PV module and heating and cooling load in building. Transparent PV modules were designed as finished material for spandrels are presented in this paper. The temperature variation of the modules with and without air gap and insulation were compared and analyzed. The results showed that the module with air gap and insulation has a much larger temperature variation than another transparent module. The temperature of the module reached by 55degree C under vertical irradiance of lower 500$W/m^2$. And the temperature difference between these modules was about 15degree C. To analyze the output performance of module according to temperature variation, separate module was manufactured and measured by sun-simulator. The results showed that 1 degree temperature rise reduced about 0.45% of output power.

• Journal of the Korea Society of Computer and Information
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• v.27 no.10
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• pp.147-153
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• 2022

Most of the metaverse service is a gamification type of metaverse solution composed by placing 3D objects on a 360 panoramic world base. However, the metaverse webtoon service is lacking in implementation and research. In this study, a method for realizing a 2D flat image form in a 3D space and a realistic 360-degree panoramic webtoon metaverse service were studied. The research process consisted of basic storytelling and design work for webtoon production, panoramic image creation to convert the produced image into 360-degree form, and content creation process for viewing 360-degree directions. Finally, we implemented shading and material work with game engine tools so that you can enjoy virtual reality-based webtoons. The webtoon-based metaverse study studied the process of creating a 360-degree panoramic webtoon from content that can only be viewed in 2D format. Accordingly, it is thought that webtoons will also be presented as a standard for the production and implementation method for the metaverse service.

• Journal of Environmental Science International
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• v.27 no.5
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• pp.291-297
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• 2018

Vertical farming systems offer many advantages in urban spaces. They have also been proposed as an engineering solution to increase the productivity per unit area of cultivated land by extending crop production in the vertical dimension. However, soil water retention is a major constraint affecting the plant environment. This study analyzed the effects of growth environment of Tropaeolum majus and Fragaria spp., on the vertical farming system, by using four different types of cover material types including sphagnum moss (Control), a shading net (S.N.), multi-layered fabric (M.L.F.), and non-woven fabric (N.W.F.). The volumetric soil moisture contents and plant characteristics were investigated from May to September 2014. Plant materials were individually cultivated in hanging baskets measuring $30{\times}17{\times}17cm$, filled with a mixture of soil and perlite, and placed at 1.5m height. Each treatment was performed in quadruplicate and consisted of five plants, amounting to a total of 20 plants. The analysis indicated that different covers were associated with multiple functions and soil water retention improvements may have a positive impact on the vertical farming system. The difference in soil water retention increased in the following order: M.L.F. > Control > N.W.F. > S.N.. Furthermore, the differences in plant height and survival rate increased in the following order: M.L.F. > Control > N.W.F. > S.N. Therefore, M.L.F yielded satisfactory good response for the vertical farming system of cover materials. Our results clearly demonstrate that vertical spaces represent an attractive alternative to urban farming and suggest that further increases in yield may be achieved via different cover materials in vertical farming using hanging baskets.

• Korean Journal of Soil Science and Fertilizer
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• v.12 no.1
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• pp.49-53
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• 1979

Effects of temperature and light intensity on photosynthesis, respiration and chlorophyll content of ginseng (Panax ginseng C. A. Meyer) were as follow. 1. Optimum light intensity for apparent photosynthesis at $25^{\circ}C$ was 25Klux($1.35mgCO_2/dm^2{\cdot}hr$) for two years old ginseng grown in pot and 30Klux($1.94mgCO_2/dm^2{\cdot}hr$) for the six years old palmate cut leaves. Optimum temperature at 25Klux was $15^{\circ}C$ ($1.40mgCO_2$) for the 2 years old and 20 to $22^{\circ}C$ ($2.03mgCO_2$) for the 6 years old. 2. Dark respiration increased almost linearly with the increase of air temperature till $25^{\circ}C$ (2.6times between $16^{\circ}C$ to $25^{\circ}C$ for the 6 years old and 1.8 times between $15^{\circ}C$ to $25^{\circ}C$ for the 2 years old). Dark respiration was 11.1 % of net photosynthesis at $16^{\circ}C$, 17.8% at $25^{\circ}C$ for the 6 years old and 40% at $15^{\circ}C$, 64.7% at $25^{\circ}C$ for 2 years old. 3. Stomata appeared only in abaxial surface (lower epidermis) and stomatal frequency was $37per\;mm^2$. 4. Above results together with other informations quoted here strongly suggest that air temperature is much better criteria than light intensity for the improvement of shading roof material and shading construction. That is to promise maximum light intensity unless air temperature is above $25^{\circ}C$.

• Korean Journal of Plant Resources
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• v.31 no.4
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• pp.378-383
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• 2018

This study was carried out to investigate the optimum cultivation distance for high yielding cultivation of the new variety of Gomchwi in highland and lowland. The test material was used 'Sammany' variety and the area was cultivated with a highland of 750 m above sea level and a lowland of 20 m above sea level. The planting distance was 5 treatments of $20{\times}20cm$, $20{\times}30cm$, $30{\times}30cm$, $35{\times}40cm$ and $40{\times}40cm$, and the plant was cultivated at 35% shading net in the open field. The annual growth of 'Sammany' variety was higher in the highland than in the lowland, but the number of leaves was higher in the lowland than that in the highland. The leaf number per plant was the highest in the $40{\times}40cm$ plot and the more the planting distance was, the more tendency was. However, the leaf weight per plant was higher in the highland than in the lowland. The number of leaves per 10a were higher in the lowland than that of highland and the tendency was more as the planting distance was narrower. Yields were slightly higher in the highland than that of lowland and the highest treatment plot was 2,983 kg/10a in $20{\times}20cm$. In the second year, the growth was high in the highland, and the highland was high in the leaf number and leaf weight and the same tendency in the yields. Among the planting distances, Yields in both areas were the highest in the $20{\times}20cm$ treatment, with 3,369 kg/10a in lowland and 7,257 kg/10a in highland. The growth of the third year was slightly better in the highland than that of the lowland but the difference was not significant. However, the number of leaves and leaf weight per plant were higher in the lowland than that of highland. And, in terms of leaf number and yield per 10a, it was also higher in the lowland than that in the highland. The narrower the planting distance was increased yields, and the highest yield was 6,051 kg/10a in $20{\times}20cm$. The lowland was high in yield until the third year, but the highland was the highest in the second year and decreased slightly in the third year. The narrower the planting distance in the both areas, the higher the yield, and the leaf size tended to be small.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.64 no.2
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• pp.152-158
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• 2019

This study was conducted to develop and prove the effects of an agronomical pest control measure on ginseng cultivated by direct seeding in paddy field, and the results obtained are as follows. Decomposition of ginseng in field during overwintering was due to gray mold rot caused by Botrytis cinerea, which occurred in October or November of 2016 and intensified in February and March the following year. The occurrence rate of gray mold rot based on shading materials was 6.5%, 16.8%, and 29.5% with light-proof paper, PE shade net, and rice straw shade, respectively. The initial infection occurred in the leaves prior to wintering and secondary infection occurred in the stems after wintering. The rate of screrotium formation by gray mold in the above-ground parts of ginseng tended to increase: 26.6% on October 20, 33.7% in November 20, and 41.8% on December 20. The force needed to remove the leaves and stems from withered ginseng was 0.2, 0.94, 2.5, and 5 kg for 1-, 2-, 3-, and 4- and 5-year holds; the force required was 1 kg after wintering, making it relatively easy to remove. The disease incidence rate after the removal of leaves and stems was 2.5%, 1.2%, and 2.2% in 4-, 5-, and 6-year-old plants, respectively, and a disease high incidence rate of 8.8%, 13.0%, and 18.2%, respectively, was seen when the leaves and stems were not removed. In both transplanting and direct seeding, the miss-planted rate decreased and the germination rate increased when shading material was removed and the surface of ridge was covered with soil or vinyl.