• Geomechanics and Engineering
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• 제14권1호
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• pp.83-90
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• 2018

A series of pullout tests were carried out on waste tire treadmats of various weave arrangements, with confining stresses ranging from 9 to 59 kPa approximately, in order to investigate the pullout behavior and to apply the results to the design of treadmat reinforced soil structures. A treadmat reinforcement can be considered as belonging to the extensible type thus progressive failure would develop in every tread. The pullout capacity of a treadmat was found to be generally equal to the sum of capacities of the longitudinal treads, with minor enhancement realized due to the presence of transverse treads. Pullout failures occurred in treadmats under light surcharge and with treadmats with higher material presence per unit area, while breakage failures occurred in treadmats under heavier surcharge and with treadmats with higher ratio of opening. The pullout capacity of a treadmat increased with increasing surcharge height and treadmat stiffness. A pullout test on a commercially available geogrid was also carried out for comparison and the pullout capacity of a treadmat was found higher than that of the comparable geogrid under identical loading conditions, indicating the merit of using the treadmat as an alternative to the chosen geogrid.

• 조명전기설비학회논문지
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• 제28권10호
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• pp.9-15
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• 2014

Standby power, so called an electric vampire, is a power which is consumed by appliances and office equipments connected to power sources while the devices are not performing. Sensor luminaires consist of PIR(Pyroelectric Infrared Ray) sensor, illuminance sensor(CdS), and light source. The sensor luminaires are one of the devices that consume a huge amount of standby power; it stands by for an average sum of 23 hours a day and performs only when moving subjects are detected under it, which barely takes up an hour per day. The purpose of this study is to provide basic materials to the selection of standby power items and to enable to explore a way to decrease the standby power by measuring and analyzing the power consumption of sensor luminaires. According to the results, the average standby power of LED sensor luminaires is 1.1W which is significantly higher than other products, and decrease in the standby power consumption of SMPS is important through the measurement.

• 반도체디스플레이기술학회지
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• 제13권2호
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• pp.23-28
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• 2014

For the reconstruction of three-dimensional (3D) shape of microscopic objects through shape from focus (SFF) methods, usually a single focus measure operator is employed. However, it is difficult to compute accurate depth map using a single focus measure due to different textures, light conditions and arbitrary object surfaces. Moreover, real images with diverse types of illuminations and contrasts lead to the erroneous depth map estimation through a single focus measure. In order to get better focus measurements and depth map, we have combined focus measure operators by using genetic algorithm. The resultant focus measure is obtained by weighted sum of the output of various focus measure operators. Optimal weights are obtained using genetic algorithm. Finally, depth map is obtained from the refined focus volume. The performance of the developed method is then evaluated by using both the synthetic and real world image sequences. The experimental results show that the proposed method is more effective in computing accurate depth maps as compared to the existing SFF methods.

• Wind and Structures
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• 제38권3호
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• pp.161-170
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• 2024

In recent years, there have been an increasing number of experimental studies showing the need to include robustness criteria in the design process to develop complex active control designs for practical implementation. The paper investigates the crosswind aerodynamic parameters after the blocking phase of a two-dimensional square cross-section structure by measuring the response in wind tunnel tests under light wind flow conditions. To improve the accuracy of the results, the interpolation of the experimental curves in the time domain and the analytical responses were numerically optimized to finalize the results. Due to this combined effect, the three aerodynamic parameters decrease with increasing wind speed and asymptotically affect the upper branch constants. This means that the aerodynamic parameters along the density distribution are minimal. Taylor series are utilized to describe the fuzzy nonlinear plant and derive the stability analysis using polynomial function for analyzing the aerodynamic parameters and numerical simulations. Due to it will yield intricate terms to ensure stability criterion, therefore we aim to avoid kinds issues by proposing a polynomial homogeneous framework and utilizing Euler's functions for homogeneous systems. Finally, we solve the problem of stabilization under the consideration by SOS (sum of squares) and assign its fuzzy controller based on the feasibility of demonstration of a nonlinear system as an example.

• 반도체디스플레이기술학회지
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• 제7권3호
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• pp.41-43
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• 2008

The electro-optical characteristics of the Liquid Crystal on Silicon (hereinafter "LCOS") micro-display on vertically alignment (VA) mode were studied depending on various cell gaps. 5 different cell gaps, such as $1.4{\mu}m,\;1.8{\mu}m,\;2.1{\mu}m,\;2.4{\mu}m$ and $2.8{\mu}m$, were selected. The reflectance-voltage (R-V) characteristics, distributions of reflected light and reflectance were calculated with 3-dimmensional LC code. At the center of cell, the smallest $1.4{\mu}m$ cell gap showed the lowest reflectance and the largest $2.8{\mu}m$ cell gap showed the highest reflectance due to the surface anchoring effect. In case of $2.1{\mu}m$ cell gap, the sum of reflectance overall cell was the highest value. Considering the reflectance and RV curve characteristic, the optimized cell gap was $2.1{\mu}m$.

• Restorative Dentistry and Endodontics
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• 제25권1호
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• pp.123-132
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• 2000

To overcome problems of conventional glass ionomers, resin components have been added to glass ionomers. On a continuum between glass ionomers and composites are a variety of blends, employing different proportions of acid-base and free radical reactions to bring about cure. Popular groups defined between the ends are resin-modified glass-ionomers(RMGIs), polyacid-modified composite resins(Compomers) and ionomer modified resins. These groups show different clinical properties, and in selecting these materials for a restoration, one should sufficiently understand these different setting properties. In this study, some difference in the setting characteristics of different groups of hybrid ionomers were examined. Two RMGIs (Fuji2 LC,GC / Vitremer, 3M), three Compomers (Dyract AP, Dentsply / F2000, 3M / Elan, Kerr) were involved in this study. The identification of the setting characteristics of different groups was achieved by a two-stage study. First, thermal analysis was performed by a differential scanning calorimeter, and then the hardness of each group at different depth and time were measured by a micro-hardness tester. Thermal analysis was performed to identify the inorganic filler content and to record the heat change during setting process. The setting process was progressed for each material by chemical set mode and light-cured mode. In the hardness test, samples of materials were prepared with a 6mm-diameter metal ring, and the hardness was measured at the top, and 1mm, 2.5mm, 4mm below at just after a 40 second-cure, and after 10 minutes, 24 hours, and 7 days. Statistical analysis was performed by Mann-Whitney rank sum test to assess significant differences between set modes and types of materials, and by ANOVA and T-test to evaluate the statistical meanings of data at different times and depths of each materials. Followings are findings and conclusions derived from this study. Thermal analysis; 1. Compomers show no evidence of chemical setting while RMGIs exhibit heat output during the process of chemical setting. 2. Heat of cure of RMGIs exceed Compomers. 3. The net heat output of RMGIs through light-cured mode is higher than through chemically set mode. Hardness test; 1. Initial hardness of RMGIs immediately after light cure is relatively low, but the hardness increases as time goes by. On the contrary, Comomers do not show evident increase of the hardness following time. 2. Compomers show a marked decrease of setting degree as the depth of the material increases. In RMGIs, the setting degree at different depths does not significantly differ.

• 한국식품위생안전성학회지
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• 제24권4호
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• pp.385-390
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• 2009

This survey was conducted to monitor the total sugar, sodium, and artificial sweetener contents of light meals from the school zone in Gwangju, from November, 2008 to April, 2009. A total of 100 samples were tested. HPLC/ELSD was used for the determination of total sugar contents and AAS for sodium contents. Total sugar amounts were the sum of both mono-and disaccharide according to nutritional information standard defined by the Korea Food and Drug Administration. The results were as follows by the form of total sugar content(sodium content): $5.7\;{\pm}\;1.9%$($4.6\;{\pm}\;1.6\;mg/g$) for Tteokbokki, $7.6\;{\pm}\;5.1%$($5.4\;{\pm}\;2.7\;mg/g$) for Chicken(skewed), $15.4\;{\pm}\;3.2%$($3.0\;{\pm}\;0.9\;mg/g$) for Bun(fish-shaped), $0.6\;{\pm}\;0.3%$($3.7\;{\pm}\;1.0\;mg/g$) for Sundae, $0.9\;{\pm}\;0.3%$($7.4\;{\pm}\;1.4\;mg/g$) for Oden(with broth), $20.5\;{\pm}\;6.2%$($2.9\;{\pm}\;0.6\;mg/g$) for Waffle, $6.8\;{\pm}\;2.2%$($4.7\;{\pm}\;1.0\;mg/g$) for Hotdog, $14.2\;{\pm}\;2.8%$($3.1\;{\pm}\;1.6\;mg/g$) for Hotteok, $6.6\;{\pm}\;2.1%$($3.9\;{\pm}\;0.6\;mg/g$) for Toast, $10.1\;{\pm}\;3.7%$($2.3\;{\pm}\;0.7\;mg/g$) for Fry(sweet potato), $1.6\;{\pm}\;0.7%$($4.0\;{\pm}\;0.7\;mg/g$) for Fry(etc), and $9.3\;{\pm}\;2.4%$($4.0\;{\pm}\;0.6\;mg/g$) for Doughnut. In addition, sodium saccharin, one of the artificial sweeteners, was tested. Among 60 samples from February to April, 2009, 11 samples had sodium saccharin(6.7~101.0 mg/kg).

• 한국양식학회지
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• 제6권4호
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• pp.295-310
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• 1993

자주복, Takifugu rubrips 종묘의 효율적인 대량 생산 기술을 개발하기 위하여 1989, 1991년과 1992년 5월에 각각 인공 부화한 자$\cdot$치어를 대상으로 실시한 rotifer(Brachionus plicatilis)의 적정 공급시기, 조도와 LD cycle에 따른 Artemia 포식량 및 초기 성장에 대하여 조사한 결과를 요약하면 다음과 같다. 부화 자어의 적정 rotifer 공급 개시 시기는 부화후 2-5일 사이며 그 생존율은 $96.5-90.0\%$였다. 각 성장 단계별 최대 포식량에 도달할 수 있는 최저 조도는 전장 6mm에서는 1000룩스였고, 8mm에서 600룩스, 10mm에서 12mm 사이에서는 200룩스로 성장에 따라 차츰 저조도하에서 포식이 가능하였다. 전장 6-12mm 사이의 자$\cdot$치어에 있어서 전장 (X)과 최대포식량에 달하는 조도 (Y)와 의 관계는 Y=2200-200X(r=-1.0000)의 직선회귀식으로 나타낼 수 있었다. 세 가지의 L:D cycle 조건 (12: 12, 14:10, 16.8) 하에서 전장 6-14mm까지의 성장 단계별 자$\cdot$치어의 포식량은 대체로 광 조사 시간이 길어질수록 많아지는 경향을 보였으나 큰 차이는 없었다. 모화후 경과일수 (X)와 전장 (Y)의 성장 관계식은 부화후 3일부터 36일까지는 Y=1.6427+0.2540X (r=0.9814)로 표시되었고, 36 일부터 68 일까지는 Y=-33.1452+1.1867X(r=0.9854)로 나타났다. 이 기간 동안 수온은 $21.3\pm1.67^{\circ}C$ 범위였으며 68일간의 생존율은 $24.1\%$였다.

• Restorative Dentistry and Endodontics
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• 제21권1호
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• pp.174-186
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• 1996

The purpose of this study was to evaluate the adaptability to tooth structure of composite resin and glass ionomer cement according to filling methods. In this study. two class V cavities were prepared on the buccal and lingual surface of each tooth of forty extracted human premolars. and they were randomly assigned into 4 groups with 10 teeth. The cavities of each group were filled with the CLEARFIL FII self curing resin(Control Group), Z-100 light curing resin (Group 1). $Vitremer^{TM}$ light curing glass ionomer cement(Group 2) and Z-100 light curing resin over the $Vitremer^{TM}$ liner(Group 3). The specimens underwent temperature changed from $5^{\circ}C$ to $55^{\circ}C$ five hundred times. After thermocycling. specimens were immersed in 2% methylene blue solution and stored in 100% relative humidity at $37^{\circ}C$ for 24 hours. And then. the specimens sectioned buccolingually. Degree of dye penetration at tooth-restoration interfaces were examined by Tool maker's microscope(x 200) and Image analyzer. The results were as follows : 1. On the occlusal margin. among the experimental groups. the group 2 showed the highest dye penetration($2.40{\pm}0.68$) and the group 3 showed the lowest dye penetration($1.15{\pm}0.37$). There was significant difference among the experimental groups(p<0.001). 2. On the gingival margin, among the experimental groups, the group 1 showed the highest dye penetration($3.30{\pm}0.57$) and the group 2 showed the lowest dye penetration($1.65{\pm}0.49$). There was significant difference among the experimental groups(p>0.001). 3. About total degree of dye penetration, the group 1 showed the highest dye penetration($2.25{\pm}1.17$) and the group 3 showed the lowest dye penetration ($1.43{\pm}0.55$). There was significant difference among the experimental groups(p<0.001). 4. The sum of dye penetration at occlusal margin was less than gingival margin. There was significant difference between occlusal margin and gingival margin (p<0.001). The results showed that differences were more pronounced at the gingival margin. Composite restorations inserted over the glass-ionomer liner demonstrated significantly less leakage than single restoration that used composite resin or glass-ionomer cement.

• 자원환경지질
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• 제29권5호
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• pp.545-559
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• 1996

Rare metal (Nb-Zr-REE) ore deposits are located in the Chungju area. Geotectonically, the rare metal ore deposits are situated in the transitional zone between Kyeonggi massif and Okcheon belt. The rare metal deposits are distributed in Kyemyeongsan Formation which consist of schist and alkaline igneous rocks. Alkali granite has suffered extensive post-magmatic metasomatism and hydrothermal processes. The ore contains mainly Ce-La, Ta-Nb, Y, Y-Nd, Nd-Th group minerals. More than 15 RE and REE minerals are found in the ore deposits. Allanite, one of the Ce-La rich REE minerals belonging to the epidote group, is the most common mineral in the studied area. The allanite- bearing rocks may be devided into seven types by features of occurrence and mineral associations; zircon type (ZT), allanite-vein type (AT), feldspar type (KT), fluorite type (FT), quartz-mica type (QT), iron-oxide type (MT), and amphibole type (HT). The allanite veins (AT) and zircon rich rocks (ZT) contain the highest total REE contents. Differences in REE abundance can be interpreted in terms of varying portions of magmatic hydrothermal fluid. Petrographical and chemical data are presented for allanites which were collected from different types. The allanites show wide variations in optical properties, due in part to differences in their chemical composition (depending on the types) and to the degree of crystallinity of the individual specimens. Allanite metamicts in biotite are generally surrounded by well developed pleochroic haloes. Usually, allanite is accompanied by zircon and other REE-bearing minerals. CaO and total REE contents $({\sum}RE_2O_3)$ range from 9.29 to 18.79% and 11.66 to 26.31%, respectively. Also, SiO, (28.87~32.61%), $Al_2O_3$ (8.30~16.88%), and $Fc_2O_3$ (16.74~24.38%) contents show varying contents from type to type. The ${\sum}RE_2O_3$ of allanite has positive relationships with $Fe_2O_3$ and negative relaton with CaO, $SiO_2$, and $Al_2O_3$ Backscattered electron microscope images (BEl) of allanite shows that the its mineral composition and texture is very complex. The allanite-bearing hosts show distinct light REE enrichment with strong negative Eu anomaly except for HI. The HT has an almost flat REE distribution pattern with a small negative Eu anomaly. The chemical variation of the allanites with occurrences and mineral association can be related to condition of temperature and oxidation states in precipitation environment.