• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.169-169
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• 2008

To keep pace with scaling trends of CMOS technologies, high-k metal oxides are to be introduced. Due to their high permittivity, high-k materials can achieve the required capacitance with stacks of higher physical thickness to reduce the leakage current through the scaled gate oxide, which make it become much more promising materials to instead of $SiO_2$. As further studying on high-k, an understanding of the relation between the etch characteristics of high-k dielectric materials and plasma properties is required for the low damaged removal process to match standard processing procedure. There are some reports on the dry etching of different high-k materials in ICP and ECR plasma with various plasma parameters, such as different gas combinations ($Cl_2$, $Cl_2/BCl_3$, $Cl_2$/Ar, $SF_6$/Ar, and $CH_4/H_2$/Ar etc). Understanding of the complex behavior of particles at surfaces requires detailed knowledge of both macroscopic and microscopic processes that take place; also certain processes depend critically on temperature and gas pressure. The choice of $BCl_3$ as the chemically active gas results from the fact that it is widely used for the etching o the materials covered by the native oxides due to the effective extraction of oxygen in the form of $BCl_xO_y$ compounds. In this study, the surface reactions and the etch rate of $Al_2O_3$ films in $BCl_3/Cl_2$/Ar plasma were investigated in an inductively coupled plasma(ICP) reactor in terms of the gas mixing ratio, RF power, DC bias and chamber pressure. The variations of relative volume densities for the particles were measured with optical emission spectroscopy (OES). The surface imagination was measured by AFM and SEM. The chemical states of film was investigated using X-ray photoelectron spectroscopy (XPS), which confirmed the existence of nonvolatile etch byproducts.

• Weed & Turfgrass Science
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• v.1 no.4
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• pp.18-23
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• 2012

To determine the effect of winter green manure crops for tillage and no-tillage organic pepper cultivation in plastic film house, five different green manure crops were cultivated during winter season. In nutrition composition of green manure crops, total nitrogen contents were higher in Vicia hirsuta and Vicia angustifolia than any other crops. The average dry weights of green manure crops were 8.3 ton per ha in tillage and 7.0 ton per ha in no-tillage, among green manure crops that of Secale cereale was the highest. Fertilizer supply was depended on the biomass of the cultivated green manure crops and nutrition contents, total nitrogen supply of V. angustifolia was 226 kg and that of S. cereale was 251 kg per ha in tillage field. In no-tillage field, N-supply of V. angustifolia was 197 kg and that of S. cereale was 222 kg per ha. In yield components of red pepper, fruit numbers per plant were 55.5 in green manure crop tillage and 37.0 in no-tillage cultivation. Among green manure crops, the yield of dried red pepper was the highest for V. angustifolia in both green manure crop tillage and no-tillage cultivation.

• Korean Journal of Food Science and Technology
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• v.53 no.5
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• pp.634-639
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• 2021

This study investigated the effects of cold plasma (CP) treatment on the properties of biopolymer films prepared with defatted mustard meal (DMM films). CP treatments using N₂, O₂, He, Ar, and dry air did not affect the tensile properties, water vapor permeability, color, and morphology of DMM films, whereas the treatments using He and Ar improved their printability. The tensile strength (TS) of O₂- or air-CP-treated DMM films and the elastic modulus (EM) of O₂-, He-, Ar-, or air-CP-treated films were lower than those of the untreated films. An increase in the power of Ar-CP treatment resulted in an increase in EM. The optimum treatment power and time for minimizing yellowness changes by Ar-CP treatment were 420 W and 40 min, respectively. The results demonstrated the potential application of CP treatment to improve the film properties of DMM films and possibly other agricultural by-product-based biopolymer films, making the films more applicable to food packaging.

• Applied Chemistry for Engineering
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• v.32 no.6
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• pp.690-694
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• 2021

Carbon spheres (CS) were fabricated using glucose as a precursor in the hydrothermal method. Hollow TiO₂ (H-TiO₂) spheres with 200 nm, 500 nm, and 1,200 nm were synthesized by CS/TiO₂ core-shell particles via a sol-gel and calcination method. H-TiO₂ spheres with nano and micron sizes were characterized using FE-SEM, HR-TEM, and X-ray diffraction. The CIE color coordinate, solar reflectance, and heat shield temperatures of H-TiO₂/polyacrylate (PA) composite film were investigated using a UV-Vis-NIR spectrometer and homemade heat insulation temperature measuring device. H-TiO₂/PA composites exhibit excellent thermal insulation since the hollow structure filled with dry air has low thermal conductivity and near infrared light reflecting performance. The thermal insulation increased with increasing the hollow sphere (HS) size on H-TiO₂/PA composites. The PA composite film mixed with H-TiO₂ filled with 1200 nm HS reduced the heat shield temperature by 26 ℃ compared to that of the transparent glass counterpart.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.34 no.4
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• pp.131-138
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• 2024

In this study, the microstructure and plasma resistance characteristics of 35Bi₂O₃-15Al₂O₃-50SiO₂ (BiAl SiO) and 35Bi₂O₃-7.5Al₂O₃-50SiO₂-7.5AlF₃ (BiAlSiOF) glass layers coated on sintered alumina substrates were investigated according to the sintering conditions. The coated layers were formed using the bar coating method and then sintered at a temperature in the range of 700~900℃, which corresponds to the temperature before and after the hemisphere forming temperature, after a debinding process. The plasma resistance of the two coated glasses was approximately 2~3 times higher than that of the quartz glass, and in particular, the BiAlSiOF glass film with F added showed higher plasma resistance than BiAlSiO. It is thought to be due to the effect of suppressing the reaction with fluorine gas by adding fluorine to the glass. When the sintering time was increased at 700℃ and 800℃, the plasma resistance of both glasses improved, but when the sintering temperature was increased to 900℃, the plasma resistance decreased again (i.e., the etching rate increased). This phenomenon is thought to be related to the crystallization behavior of both glasses. The change in plasma resistance depending on the sintering conditions is thought to be related to the appearance of Al and Bi-rich phases.

• Korean Journal of Soil Science and Fertilizer
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• v.37 no.2
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• pp.74-82
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• 2004

This study was conducted to estimate the optimum application rate of fertilizer N based on $NO_3-N$ concentration in soils for tomato (Lycopersicon esculentum Mill.) cultivation in plastic film house. Tomato plants were cultivated with and without fertilizer in twelve soils which have different concentrations of $NO_3-N$ ranging from 46 to $344mg\;kg^{-1}$. Dry weight (DW) of above-ground part of tomato with no fertilizer ranged from 28.9 to $112.5g\;plant^{-1}$, depending on N-supplying capability of soils. The soil $NO_3-N$ was positively correlated with DW ($r=0.83^{**}$) and N uptake ($r=0.78^{**}$) by tomatoes in no fertilizer treatment, and negatively correlated with fertilizer effciencies resulted from the differences of DW and N uptake between fertilized and non-fertilized plot. The relationships between soil $NO_3-N$ concentration and DW, N uptake, and fertilizer efficiency were analyzed to determine the critical levels of soil $NO_3-N$ for tomato cultivation. The limit critical levels of soil $NO_3-N$ were estimated to be more than $280mg\;kg^{-1}$ for no application of fertilizer N and to be less than $50mg\;kg^{-1}$ for recommended application of fertilizer N. These critical levels of soil $NO_3-N$ were nearly the same as those calculated from regression equation between electrical conductivity(EC) and soil nitrate for critical levels of EC in recommendation equation of fertilizer N for tomato under the plastic film house by NationaI Institute of Agricultural Science and Technology. Consequently, the optimal application rate of ferdilizer N for tomato cultivation in the soils containing $NO_3-N$ concentration between $280mg\;kg^{-1}$ and $50mg\;kg^{-1}$ was estimated by the equation Y = -0.4348X＋121.74, where Y is the percent(%) to the recommended application rate of N fertilizer and X is the soil $NO_3-N$ concentration ($mg\;kg^{-1}$).

• Journal of Bio-Environment Control
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• v.9 no.4
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• pp.193-200
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• 2000

The object of this study is to investigate the quality change of sweet basil grown with selenium(Se) in hydroponic culture. Sweet basil was cultured with 1 fold herb nutrient solution as suggested by European vegetable R & D Center in Belgium. Before three weeks harvest, sodium selenate(N $a_2$Se $O_4$) was supplied to 2 and 4 mg. $L^{-1}$ in the nutrient solution. Sweet basil was stored at 1$0^{\circ}C$ using 40um ceramic film and PET (polyethylene terephalate) for 15 days in modified atmosphere(MA) storage condition. The weight loss of sweet basil was higher in non-treatment compared to Se treatments in both of two films but it was decreased over 5% in PET treatment. Se concentrations in leaf tissues increased in the response to the treated levels of N $a_2$Se $O_4$concentrations, and this tendency was appeared similar results after storage. There was no significant effect of packing materials on volatilization of Se in sweet basil. The total chlorophyll and essential oil content was increased with increasing N $a_2$Se $O_4$concentration in nutrient solution. The amount of volatilization flavor was not higher at N $a_2$Se $O_4$4mg. $L^{-1}$ treatment compare to others during storage. Se content was 112.73 ug. $g^{-1}$ dry mass at 2 mg. $L^{-1}$ treatment before storage and the decrease of Se content was observed by 50% at 15 days after storage. The condition, which N $a_2$Se $O_4$2mg. $L^{-1}$$^{plement}$ in nutrient solution during growth stage and stored with 40um ceramic film on 1$0^{\circ}C$are acceptable for maintaining of sweet basil quality. Moreover it can be a proper Se concentration for human health. Overall, Se treatment in nutrient solution has effect on promoting and maintaining quality of herb during storage life. Also, there was not significant change of essential oil compounds by volatilization of Se.mpounds by volatilization of Se.

• FLOWER RESEARCH JOURNAL
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• v.19 no.1
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• pp.15-21
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• 2011

This study investigated the effect of soil mulching materials and methods on weed occurring for the growth and flowering characteristics in Gypsophila plants cultivation. For mulching materials were used black polyethylene (PE) film, black polypropylene (PP), and green polypropylene, and these were mulched in both ridge and furrow (BRF) or only furrow, respectively. The weed was occurred total $146.2g/m^2/yr$ as dry weight in non-mulching, but $4.1{\sim}4.2g/m^2/yr$ in BRF mulching by black or green PP. Also weed control were yearly required 27.9 persons/10a in non-mulching, whereas 2.4 persons/10a in BRF mulching by black or green PP. Flower budding and blooming were roughly delayed in non-mulching and furrow mulching. Flowering characteristics such as flower stalk length, primary branches number, and stem firmness were remarkably improved in BRF mulching of black or green PP. Cut flower yield was increased on black BRF mulching or green PP in summer cultivation, while green PP BRF mulching showed better yield in in autumn cultivation. Mortality rate of Gypsophila plants after summer season was lowest as 12.4% in furrow mulching with black PP, followed by about 19.0% in green PP mulching, but highest as 39.0% in BRF mulching with black PE film. Rosette formation rate was lower in furrow than BRF mulching, and was lowest as 13.1% in BRF mulching with green PP, followed by 15.2~15.8% in BRF mulching with black PE film or black PP. So it was thought that BRF mulching with green PP was highly effective in weed control and improvement of yield and cut flower quality in Gypsophila plants cultivation.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.42 no.5
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• pp.489-496
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• 1997

This study was carried out to develop and investigate integrated mechanization system on polyethylene(P.E.) film mulching culture in sesame. Field trials were carried out to develop optimum mechanics for each step of manual operation in sesame culture and demonstrated those developed mechanics of sesame dibbling vinyl mulcher, sesame binder, sesame thresher and sesame grader at the farmer, s field of Hwasong (Kyunggi-do) in 1994 and 1995. Newly developed sesame dibbling vinyl mulcher brought saving manpower 280 hrs /ha for sowing and P.E. film mulching with it's 98％ of labour saving for the harvesting operation of sesame. Sesame Binder showed 93％ labour saving for cutting and binding with only 22 hrs /ha compared to 330 hrs /ha that of conventional. Sesame thresher was appeared to have 85％ effects of labour saving for threshing with completely dry sesame bundles at one time by 23 hrs /ha compared to 151 hrs /ha that of conventional. Sesame grader was appeared to have 72％ effects for sesame grain grading with 12 hrs /ha compared to that of conventional 54 hrs /ha. Grain yield of integrated mechanization culture system showed 6％ higher than that of coventional. Integrated mechanization culture system (sesame dibbling vinyl mulcher ＋ sesame binder ＋ sesame thresher ＋ sasame grader) showed 62％ of labour saving effects through whole steps of sesame culture by 472 hrs /ha compared to that of conventional 1, 230 hrs /ha.

• Tribology and Lubricants
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• v.22 no.6
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• pp.314-319
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• 2006

In this paper, the friction and wear characteristics of contact type sealing unit far a water turbine have been presented. The sealing unit for a small hydropower generation is to stop a leakage of circulating water from an outside of an impeller to an inside of a rolling bearing. The friction heating between a seal ring and a seal seat may radically increase a surface temperature in which increase a power loss and wear on the rubbing surface. The surface wear strongly affect to the seal life of a mechanical face seal. In this study, the hardness of a stainless steel in which is a heat-treated is 892.8 in Victors hardness and the hardness of silicone carbide of SiC is 714.1 in Victors hardness. The surface hardness of a heat-treated stainless steel is 25% high compared with that of a ceramic material of SiC. The contact modes of rubbing surfaces are a dry friction, a water film friction and a mixed friction that is contaminated by a dust, silt, and moistures, etc. These two factors of a contact rubbing modes and a material property are very important parameters on the tribological performance such as a friction and wear between a seal ring and a seal seat in primary sealing unit. The experimental result shows that the surface hardness of a seal material is very important on the friction coefficient and a wear volume. Thus, the results recommend higher hardness of a seal material, which may reduce a friction loss and increase a wear life of primary seal components.