• Korean Journal of Optics and Photonics
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• v.17 no.4
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• pp.371-380
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• 2006

We design and fabricate a novel tunable wavelength filter, which utilizes long-range surface plasmon-polaritons excited along nm-thick-metal strips. A gold metal strip, with $\sim$ cm length, 20 nm thickness, and $\sim$ 5$\mu$m width, is embedded in thick thermo-optic Polymer films supported by a silicon wafer. A dielectric Bragg grating structure is Placed on the metal strip, so that transmission signals at telecom wavelength are selected by thermal effect of the thermo-optic polymer. High extinction ratio of 25 dB and total insertion loss of $\sim$25 dB/cm can be measured by single-mode coupling of optical fibers. We also verify that wavelength tuning of the long-range surface plasmon-polariton filters can be achieved by electric current directly applied to the metal-strip waveguides.

• Korean Journal of Optics and Photonics
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• v.13 no.1
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• pp.32-37
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• 2002

Passive polarization mode splitters at λ= 1.55 ${\mu}{\textrm}{m}$ were designed and fabricated based on Ti:x-cut LiNbO$_3$ single-mode optical waveguide and two-mode interference theory. The splitting ratio with waveguide width 8 ${\mu}{\textrm}{m}$, branching angle 0.55$^{\circ}$ and interfering length 470 ${\mu}{\textrm}{m}$ showed 16.18 dB, 21.25 dB for TE and TM input polarization modes, respectively. Polarization cross-talk of -16.28 dB and -21.28 dB for TE and TM modes was achieved. Total insertion losses of 2.24 dB/cm (TE) and 2.41 dB/cm (TM) were also measured. The devices operated nearly wavelength independently over a range or 30 nm.

• Parasites, Hosts and Diseases
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• v.31 no.3
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• pp.201-206
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• 1993

Based on the morphologic characteristics of oocysts of the genus Isosporn, we have demonstrated that I. ohioensis is a relatively common Isosporn species in dogs which are resident in Chonbuk province, Korea. The prepatent period of 1. ohioensis was four days. The size of the unsporulated oocysts in fresh stool specimens was $22.9{\;}\times{\;}19.8{\;}\mu\textrm{m}$ (R = 1.16). The size of the contracted sporonts was $17.4{\;}\times{\;}16.3{\;}\mu\textrm{m}$ (R = 1.061). By 96 hours, sporulation is complete and the ratio of length/width was constant relatively. And the sizes of oocysts and sporocysts were $22.8{\;}\times{\;}20.5{\;}\mu\textrm{m}$ (R = 1.11) and $15.0{\;}\times{\;}10.8{\;}\mu\textrm{m}$ (R = 1.39), respectively. At this time it is most reliable for the measurements of oocyst sizes of 1. ohioensis to provide with the identifiable clues against the others. It is therefore recommended that the clinical fecal specimens suspected of isosporosis should first be incubated and aerated for 96 hours before a definitive parasitological diagnosis can be reached. These and other observations contribute to the understanding of the biological characteristics and laboratory and clinical diagnosis of isosporosis.

• Magazine of the Korea Concrete Institute
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• v.10 no.6
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• pp.345-352
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• 1998

Compressive strength of concrete compression members strengthend with carbon fiber laminate(CFL) were studied from the test results. Test parameters are spacing, thickness, width, ply and spliced length of carbon fiber laminates. Specimens strength with sheets failed with sudden tensile rupture of the laminate, which indicate very brittle failure mode. Test result shows that closer spacing and to increas thickness of CFL is more effective. But strengthening ratio with 1-ply CFL is more effective than that of specimen with 2-ply CFL. Compressive strength capacity of specimen splied 24cm shows almost similar strength to that of non-spliced specimen. The ultimate load carrying of specimen strengthened with CFL ranges 1.11~1.86 times of that of non-strengthened specimen.

• Journal of the Korean Wood Science and Technology
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• v.45 no.5
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• pp.511-518
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• 2017

In recent years, many interests and researches on the insulations required the multiple performances other than insulation performance. The purpose of this paper is to find the optimal ratio between wood fiber and rice-husks charcoal to develop a structural board with carbonized rice-husks. Based on these rice-husks charcoals, basic research was carried out to develop thermal insulation materials with structural performance, and the following conclusions were obtained. The MC of the board using the carbonized rice-husks was 3.2-4.1% and the density was 0.58-0.68, indicating the possibility of excellent structural material. The bending strength was 9.1-32.6 MPa in the length direction and 9.2-34.1 MPa in the width direction. It is possible to obtain the bending strength of the normally used MDF level and to find the possibility of development of the thermal insulation material having the structural performances.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.379-379
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• 2013

본 논문에서는 Normal ink jetting 공법으로 OTFT를 제작할 때 coffee stain effect에 의해서 반도체 소자의 특성이 저하되는 것을 극복하기 위해서 동일한 위치에 동일한 부피로 Droplet을 형성하는 Multiple ink jetting 공법을 통해 TIPS pentacene 결정의 Morphology와 전기적 특성이 어떻게 변화하는지 알아 보았다. Multiple ink jetting의 drop 횟수가 증가할수록 coffee stain effect에 의해서 형성된 가운데 영역의 Dendrite grain이 점점 작아지다가 7 Drops 이후로는 Big grain 만 남게 되었다. Active layer의 표면 Roughness는 drop 횟수가 증가할수록 낮아지다가 일정 count 이후로는 다시 높아지는 것을 확인할 수 있었다. 전계 이동도(mobility)는 drop 횟수가 증가할수록 커지다가 일정 count 이후로는 saturation되는 것을 확인할 수 있었다. Multiple ink jetting에 의해서 만들어진 OTFT 소자의 전계 이동도(mobility)는 1 drop과 10 drops에서 각각 0.0059, 0.036 cm2/Vs 로 6배 정도 차이가 있었다. 이것은 첫 drop에 의해 만들어진 가운데 Dendrite grain 영역이 Multiple ink jetting을 반복하면서 점점 작아지게 되어 사라지고 두꺼운 Grain 영역만 남게 된 것으로 판단된다. Vth 와 On/Off ratio는 1 drop과 10 drops에서 각각 -3 V, -2 V 그리고 $3.3{\times}10^3$, $1.0{\times}10^4$를 보였다. OTFT의 substrate로 Flexible한 polyethersulfone (PES) 기판을 사용하였고, 절연체로 Spin coating된 Poly-4-vinylphenol (PVP)가 사용되었으며, Gate 및 Source/Drain 전극은 Au를 50 nm 두께로 증착하였다. Channel의 width와 length는 각각 100 um, 40 um 였고, Gate 전극 위에 Active layer를 형성한 Bottom gate 구조로 제작되었다. Ink jet으로 제작된 TIPS pentacene의 결정성은 x-ray diffraction (XRD)와 광학 현미경으로 분석하였고 Thickness profile은 알파스텝 측정기를 이용하였으며, OTFT의 전기적 특성은 Keithley-4,200을 사용하여 측정하였다.

• Journal of The Korean Society of Agricultural Engineers
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• v.47 no.5
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• pp.87-97
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• 2005

The field scale experiment was performed to examine the effect of physical design parameters on the constructed wetland performance and recommend the feasible design of constructed wetland in Korean polder areas. Four sets (each set of 0.85 ha) of wetland (0.8 ha) and pond (0.08 ha) systems were used. Two different wetland systems, a wetland-pond system and a pond-wetland system, were studied to examine the effect of wetland and pond configuration. And two different length-to-width ratios were used, 2: 1 and 0.8: 1, to examine the effect of aspect ratio. A pond-wetland system was more preferable than a wetland-pond system, and also requires a smaller area than a wetland-pond system or a wetland system to reduce T-P. There was no difference in effluent concentration between the 2:1 system and the 0.8:1 system. Although the linear velocity of the 2:1 aspect was higher than the 0.8:1 aspect, resuspension was not a factor in this study due to a very low linear velocity. From this study and other literature review, it was found that design method of paddy rice field could be applied and expanded to the design of constructed wetland in Korea. Further investigation for the detailed design parameters of constructed wetland needs be continued for design method of paddy rice to be applied in full scale.

• Journal of The Korean Society of Grassland and Forage Science
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• v.16 no.3
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• pp.235-244
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• 1996

This experiment was carried out to evaluate the effect of pasture type on behavior pattern, change of body type and daily gain of Korean native goat at the College of Natural Science of Kon-KuK University in Chungju. The results are summarized as follows : Relative coverage of native herbage at the pasture area was 62% in initial grazing period and that final grazing period decreased by 36%. while pasture plants increased from 17 to 42%. In brush area, Quercus serrata. Quercus dentutu, Prunus surgenrii and Rhus vemicrflua of high palatability decreased with increase in grazing period. but Rhododendron mucronulatum and Rhodendrorl schlippenbachii of low palatability tended to increase. Average crude protein content at the pasture area(12.3Q) during grazing period was higher than that at the brush area(10.2). However, ADF and NDF content was lower than brush area. Ca, Mg and Na of mineral content showed highly at the brush area during the grazing period. but Na showed highly at the pasture area. Eating time Korean native goat was not different between pasture area(369 min.) and brush area(361 min.), but ruminating time showed highly at the pasture area(441 min.). Average ratio of GTlRT at the pasture and brush area was not different m 0.88 and 0.87, respectively. All body type(withers height, body length, shin circum, hip height, hip width and chest girth) showed highly that pasture area compared to brush area during the grazing periods. The daily liveweight gain showed 60.6 and 48.98 at the pasture and brush area, respectively.

• Journal of the Korea Organic Resources Recycling Association
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• v.23 no.2
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• pp.61-66
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• 2015

In this study, manufacture of kitchen garden soil and its application on the growth of Lettuce has been performed. The optimal ratio of various raw materials for pH, total nitrogen, phosphate, cations, and salt content was found to be 49 : 35 : 10 : 5 : 1(w/w) in peatmoss, livestock manure, cocopeat, zeolite, and microbial fertilizer, respectively. In the growth experiment using Lettuce, the manufactured soil obtained 21% & 20% increase in leaf length and width, 17% increase in chlorophyll, and 22% in biomass, compared to the control.

• Fisheries and Aquatic Sciences
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• v.17 no.2
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• pp.249-253
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• 2014

An 8-week feeding experiment was conducted to determine the influence of dietary distillers dried grain (DDG) on the growth and body composition of juvenile abalone Haliotis discus hannai. Five diets were formulated to contain 0% (DDG0), 15% (DDG15), 30% (DDG30), 45% (DDG45), and 60% (DDG60) DDG, and three replicate groups of abalone (average body weight: $3.6{\pm}0.21$ g) were fed one of the experimental diets at a feeding rate of 5% body weight per day once daily (17:00 h) for 8 weeks. Survival, shell length, and shell width of juvenile abalone were not affected by dietary DDG levels (P > 0.05). Weight gains of juvenile abalone fed DDG15 and DDG30 diets were not different compared to DDG0, but abalone fed DDG45 and DDG60 diets gained less weight than those fed DDG0 (P < 0.05). Soft body weight/body weight ratio of juvenile abalone fed the DDG60 diet was lower than that of those fed the DDG0 diet (P < 0.05), but proximate composition of the soft body was not affected by dietary DDG levels (P > 0.05). The results of this experiment suggest that DDG is a good replacement for wheat flour and soybean meal, and can be used up to 30% in the diet to maintain the growth performance of the juvenile abalone.