• Journal of Biomedical Engineering Research
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• v.13 no.1
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• pp.55-64
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• 1992

AB -type block copolymers of poly($\tau$-benzyl L-glutamate) (PBLG, a segment) and polyoxypropylene (POP, Bsegment) were synthesized and they were reacted with polyoxypropylene his(6-aminohexyl) (POE) to enhance the hydrophilicity of the poly- mers. The degree of swelling of the POE -crosslinked block copolymers (CPB -2) was higher than that of the block dopolymers (PB). The amount of 5-fluorouracil re- leased from CPB-2 block copolymers was greater than that from the PB block copol- ymers when they were incubated in the same period. These results indicate that the amount of 5-fluorouracil released from the matrices is proportional to the hydrophilicity of the polymers. Observing polymer surfaces by scanning electron mi- croscope, pores (diameter ; $0.5-1.5{\mu}$m) were appeared on the surface of CPB-2

• Wind and Structures
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• v.6 no.5
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• pp.347-356
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• 2003

Experimental studies on drag reduction of a circular cylinder of diameter D were conducted in the subcritical flow regime at Reynolds numbers in the range $4{\times}10^4{\leq}Re{\leq}10^5$. To shield the cylinder rear surface from the pressure deficit of the unsteady vortex generation in the near wake, two shield plates were attached downstream of the separation points to form a cavity at the base region. The chord of the shield plates, L, ranged from 0.22 to 1.52 D and the cavity width, G, was in the range from 0 to 0.96 D. It is concluded that significant drag reductions from that of a plain cylinder may be achieved by proper sizing of the shield plates and the base cavity. The study shows that using a pair of shield plates at G/D of 0.86 and angular position ${\theta}$ of ${\pm}121^{\circ}$ results in a configuration with percentage drag reduction of 40% for L/D of 0.5, and 55% for L/D of 1.0.

• Proceedings of the Korean Society of Grassland Science Conference
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• 1999.06a
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• pp.90-91
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• 1999

알팔파(Medicago sative L.)의 질소공급형태에 따른 저장질소의 함량과 재생기간 중 저장 질소의 이용 및 재생활력을 구명하고자 수경재배하에서(NH$_4$)$_2$SO$_4$, KNO$_3$, Urea, Organic-N 및 NH$_4$NO$_3$를 1mM/week로 4주간 공급후 예취하여 건물생산량을 보았으며, 다시 4mM로 40일 동안 각각의 질소 형태로 공급하여 흡수 및 잔여기관내 축적된 질소의 함량을 분석하였고, 저장된 질소에 의한 재생활력을 보기 위해 0.2mM NH$_4$NO$_3$의 형태로 동일하게 공급하였다.(중략)

• Proceedings of the Korean Society of Grassland Science Conference
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• 1999.06a
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• pp.89-90
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• 1999

페레니얼 라이그라스(Lolium perenne L.)의 질소공급형태에 따른 저장질소의 함량과 재생기간 중 저장질소의 이용 및 재생활력을 구명하고자 수경재배 하였다. (NH$_4$)$_2$SO$_4$, KNO$_3$, Urea, Organic-N 및 NH$_4$NO$_3$의 서로 다른 질소형태로 각각 1mM/week을 4주간 공급하여 건물생산량을 보았고, 예취 후 각각의 질소 형태로 4mM/40days동안 공급하여 흡수된 질소의 함량 및 잔여기관내 축적된 질소의 함량을 관찰하였으며, 예취 후 저장된 질소에 의한 재생활력을 보기 위해 0.2mM NH$_4$NO$_3$의 형태로 동일하게 공급하였다.(중략)

• Proceedings of the Korea Crystallographic Association Conference
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• 2003.05a
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• pp.16-16
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• 2003

Mismatches in a DNA duplex are mainly due to DNA duplication errors that are generated by improper function of DNA polymerase. MutS, MutL and MutH are crucial proteins for the initiation of the methyl-directed mismatch repairing in bacteria. MutS has an ATPase activity md recognize the mismatched or unpaired bases on DNA. After binding to a mismatch, MutS recruits MutL to mediate the activation of MutH an endonuclease, which cleaves the 5' site of d(GATC) on the un-methylated strand. Both MutL and MutS also have essential roles in the subsequent removal and re-synthesis of the daughter strand. We have determined the crystal structures of either intact or active fragments of each of these proteins, both alone and complexed with ligands (DNA, ADP and ATP). The biochemical and mutagenesis studies based on the detailed 3-D structures led to new insights into the role of the ATPase activity of MutS in the mismatch recognition and directions for future investigation of mismatch repair.

• Proceedings of the KIEE Conference
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• 2000.07b
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• pp.952-954
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• 2000

In the cleaning-water treatment process, the flocculation machine is operated by the V.S motor when the coagulation-facility of the coagulation-process is operated. But after the flocculation machine is stopped by an instantaneous power failure, the transient takes place when the coagulation facility is re-started. To improve the transient state, we developed the reinforcement-circuit which had the function of soft-start and adapted to the field. As a result of this study, we reduced the damage of facilities and had the safety in maintaining the quality of water and improved the efficiency in the maintenance and the management.

• Smart Structures and Systems
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• v.25 no.1
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• pp.105-109
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• 2020

The authors address the problem of ameliorating or updating existing educational buildings. This building typology is quite sensitive to social and media pressure, mainly when accidents have occurred nearby. When a building is classified as unsatisfactory, the current code requirements oblige one to re-design the building with significant penalty factors in the resistance values. Often the only solution is to destroy the existing facility and to build a new one. When attempting to preserve the existing building, higher levels of safety are demanded by the society and this can only be achieved by innovative system architectures. The authors propose and discuss a prototype that can be easily adopted to retrofit small educational buildings as the ones common in small municipalities. The higher performance is pursued by a special design of the control scheme, with new control devices and special control laws.

• Proceedings of the KIEE Conference
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• 1993.07b
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• pp.1292-1294
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• 1993

This paper proposes a new structure of polycrystalline silicon(poly-Si) thin film transistor(TFT) having a thick gate-oxide below the gate edge. The new structure is fabricated by the gate re-oxidation in wet ambient. It is shown that the thick gate-oxide below the gate edge is effective in reducing the leakage current and the gate-drain overlap capacitance. We have simulated this device by using the SSUPREM4 process simulator and the SPISCES-2B device simulator. As a simulation result it is found that the new structure provides a low tentage current less than 0.2 pA and achieves a on/off ratio as high as $5{\times}10^7$.

• Analytical Science and Technology
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• v.36 no.5
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• pp.250-257
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• 2023

The development of a spectrofluorimetric method for the determination of trimethoprim according to the reaction between O-phthalaldehyde (OPA) in highly alkaline media, and 2-mercaptoethanol (2ME) and this reaction gives fluorescent product measured at (458) nm when excited at (342) nm. The optimization of the analytical parameters that influence intensity was investigated. The intensity of fluorescence of the formed product was linearly related to the concentration of trimethoprim in the (100-1200) ng mL^-1 range. The limit of detection and limit of quantification were estimated to be (22.54) ng mL^-1 and (75.15) ng mL^-1 respectively. The utility of the proposed methods was successfully verified by analysis of trimethoprim in pure and real pharmaceutical preparations with high accuracy, the recovery percentages Re%, were found to be (100.5) % and (99.76) % for pure drug and pharmaceutical preparations respectively.

• Journal of Positioning, Navigation, and Timing
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• v.13 no.2
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• pp.149-158
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• 2024

Global Navigation Satellite System (GNSS) receivers are becoming increasingly sophisticated, equipped with advanced features and precise specifications, thus demanding efficient and high-performance hardware platforms. This paper presents the design and implementation of a Field-Programmable Gate Array (FPGA)-based GNSS receiver development platform for multi-band signal processing. This platform utilizes a FPGA to provide a flexible and re-configurable hardware environment, enabling real-time signal processing, position determination, and handling of large-scale data. Integrated signal processing of L/S bands enhances the performance and functionality of GNSS receivers. Key components such as the RF frontend, signal processing modules, and power management are designed to ensure optimal signal reception and processing, supporting multiple GNSS. The developed hardware platform enables real-time signal processing and position determination, supporting multiple GNSS systems, thereby contributing to the advancement of GNSS development and research.