• Proceedings of the IEEK Conference
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• 2003.07b
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• pp.1097-1100
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• 2003

Tunable thermo-optic filter for WDM system was designed and fabricated. The basic structure of the filter was a Fabry-Perot resonator and the center cavity layer was poly-Si. Quardraple layers of low and high refractive index materials were used as DBR mirrors. Tuning and transmission efficiencies was measured and compared with the simulation results. Tuning range of 9.4 nm can be obtained by 64.7$^{\circ}C$ temperature changes and tuning efficiency was 0.144nm/K. The filter is to be assembled onto the micro optical bench with fiber optical path.

• Journal of Korean Society for Quality Management
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• v.16 no.1
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• pp.43-48
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• 1988

Most of silicone used for water repellent finish is MHP (methyl hydrodiene polysiloxane), which is formed by hydrolysis and condensation polymerization of MHD (methyl hydrodiene dichlorosilane: Me H Si $Cl_2$). The cross-linking theory explains the water repellent mechanism of MHP. The silicone finish on fiber could improve in handle, softness, abrasion resistance, soil repellency, tear strength and crease resistance, as well as water repellency. According to using method silicone-water repellent finishing agents, could be devided into air dry type and curing type. MHP is the typical curing type of water repellent finishing agent, and this type requires the curing temperature above $150^{\circ}C$ at least. High curing temperature is the very drawback of this curing type. For this reason, there has been global interest in the lowering of its temperature. The objective of this study is to investigate merits of alkali treatment for silicone finishing by ANOVA and LSD (least significant difference).

• Journal of Plant Biology
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• v.14 no.1
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• pp.25-31
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• 1971

In order to observe the absorption pattern of mineral elements and the nutritional components of brown rice grown in reclaimed saline areas in Korea, the four commercial varieties of rice were cultured at the average salt concentration of 6.05 mmhos/cm, $25^{\circ}C$, (0.3%) in saline soils and non-saline silty loam soils. In the saline areas the absorptin of Na and Si was relatively high while the absorption of P, K and Ca was relatively low. N was absorbed actively before the emergence of the rice grains but showed relative decrease thereafter. There was no difference in Mg content. Though brown rice in the saline areas contained sugar abundantly with small contents of protein, fat and crude fiber. There was little difference in total carbollydrate and ash contonts.

• Korean Journal of Optics and Photonics
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• v.5 no.4
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• pp.499-504
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• 1994

Ti-doped BSG (borosilicate glass) soot films on the silicone substrate have been deposited in the mixture of $SiCl_{4}$, TMB, $TiCL_{4}$ by flame hydrolysis deposition technique. The soot films are melted to form integrated fine glass films. We can fabricate thick films of serveral $10{\mu}m$ with deposition rate,more than $0.5{\mu}m$/min. Refractive index difference of BSG films are increased to more than 0.3% as function of the amount of Ti dopant. As a result of the process an optical waveguide which is simmilar with dimmension and refractive difference of optical fiber is produced. $BCl_{3}$ is widely used for B dopant, but we abtained the good results by the use of TMB in place of $BCl_{3}$. The melting point of silica soot glass is reduced to $1200^{\circ}C$ increasing B dopant. From FTIR analysis $B_2O_3$ content up to about lOmol% in BSG films. films.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.441-444
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• 2008

Ultra high performance concrete (UHPC) in this study is composed of sand, cement, silica fume, siliceous powder, superplasticizer and steel fiber. UHPC is composed of fine mineral particles below 0.5mm in diameter. In general, siliceous powder improves the mechanical properties of concrete by physical and chemical effect. Physical effect is related with filling interior voids which weaken the mechanical properties and chemical effect with reaction of $SiO_2$ with cement hydrates in a condition of high temperature and pressure. We evaluated the effect of siliceous powder's particle size on the mechanical properties of ultra high performance concrete in air pressure and $90^{\circ}C$ steam curing condition. siliceous powder's particle size in this study is in the range of $2{\mu}m$ to $26{\mu}m$. Fluidity in a fresh concrete, compressive strength, ultimate strain, elastic modulus and flexural strength in a hardened concrete was evaluated. We could find out that the smaller siliceous powder's particle size is, the better the fluidity and strength properties.

• Journal of Conservation Science
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• v.16 s.16
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• pp.27-38
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• 2004

This study was performed to characterize historical paper artefacts from 16th to 19th century from Chungbuk National University Museum (CNUM) in Korea. In order to know the fiber composition, surface features and fiber orientation in historic paper artefacts, LM, SEM and EDX analysis observations were applied. Based on tested results, it was concluded that Korean historic papers from 16 to 19th century were made of paper mulberry fibers called dak, which had 2.79-16.03 m of fiber lengthes and $4.5-26{\mu}m$ of lumen widthes, and they were relatively well preserved. According to EDX analysis, the examined papers differed to the contents of inorganics. High contents of S, Si, Ca, P and Al refer to use fillers, such as gypsum, clay and talc, for paper artifacts. In particular, half of samples contained some amounts of S, Cl and Fe. Since those inorganics might be potentially harmful for the paper permanency, therefore it should be considered special restoration measures from the preservation point of view.

• Journal of The Korean Society of Grassland and Forage Science
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• v.4 no.2
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• pp.89-97
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• 1983

This experiment was carried out in order to study the effect of seasonal changes and location differences on the productivity of the native reed (Phragmites Communis Trinius). The samples of reed were taken at about 30-days interval from May to October, 1982, on the open field of the reclaimed land, the river bank and the tideland in Chonnam area, and measured the yield, the feed compositions and in vitro dry-matter digestibility(IVD). The results are summarized as follow: 1. Plant height was rapidly heightened in May and June, and the number of leaves rapidly increased from May to August. However, dry matter yield increased until September and gradually decreased thereafter. 2. In general, the content of crude protein and the in vitro dry matter digestibility decreased with ageing, and the content of fiber increased. 3. Considerable difference by location in the chemical composition including $SiO_2$, Ca and P was observed. 4. There was a significant negative correlation (p<0.05) between the content of crude protein and that of crude fiber. There was a significant positive correlation(p<0.05) between the in vitro dry-matter digestibility(IVD) by two-stage method and the content of crude protein, and also was a significant negative correlation(p<0.05) between the content of fiber and that of crude protein.

• Journal of Korean Society on Water Environment
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• v.22 no.5
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• pp.865-870
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• 2006

The behavior and influence of EPS on membrane fouling by changing of hydraulic retention time was investigated, using lab. scale submerged membrane bio-reactor, which was operated with gravitational filtration and fed supernatant of primary sedimentation in waste water treatment plant as influent. The membrane was adopted micro-filter of polyethylene hollow fiber. EPS was analysed as polysaccharides and protein especially, into soluble and bound EPS separately. The concentration of soluble EPS was increased at short HRT, then membrane fouling was rapidly progressed and flux was depressed. The most of EPS clogged membrane pore were polysaccharides, while protein was important parameter affected on membrane fouling because of it's more accumulating in the more term operating.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1273-1274
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• 2007

In this paper, a Optical Voltage Transformer has been designed and fabricated to improve temperature stability caused by materials properties and insulation in measuring system, using single crystal $Bi_{12}SiO_{20}$ as Pockels effect cells for Gas Insulated Switchgear[GIS] System. LD[wavelength: 850nm] was used as optical source, InGaAs as optical detector to measure optical power, Polarizing Beam Splitter as Polarizer and Analyzer, and Multi-mode Optical-fiber[62.5/$125{\mu}m$] as Light transmission line. OPT was assembled in order to pockels effect, and adopted direct electric field type. The linearity of OPT maintains variation for applied voltage range from 100V - 3000V during the test of electric property, As the temperature was changed from $25^{\circ}C$ to $60^{\circ}C$. the result of this study shows that characteristics of OPT are good, and it can be reflected for practical optical sensors in GIS system.

• Korean Journal of Food Science and Technology
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• v.10 no.2
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• pp.263-268
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• 1978

To find out the possible variation in chemical composition among ginseng products, the amount of saponin, extract and other basic components in different age and portion of ginseng roots(Panax ginseng Meyer) were investigated and compared with. (1) Great difference in the amount of ash, crude protein, fiber, fat, total sugar and reducing sugar was observed among different portion of the root comparing with those of different age of the root. That of ash, crude fiber, saponin and extract produced was higher in epidermis, fiber roots and subterranean stems, while that of crude protein, total sugar, panaxadiol/panaxatriol was higher in central portion and branch of the root. (2) The amount of extract produced was affected by the solvent used. Higher amount was obtained when water was employed. It was decreased as the increase of the concentration of alcohol solvent. Futhermore, the composition and physical properties were greatly varied by the concentration of alcohol solvent. (3) The amount of total-N, $P_2O_5,\;K_2O$, and ash was higher in two to three years old roots, while those of crude $SiO_2,\;CaO,$ crude fiber, and total sugar was higher in order roots. No difference was found in amount of MgO, Fe, Zn, and Na among age of the root.