• Proceedings of the Korean Society of Applied Pharmacology
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• 1998.11a
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• pp.170-170
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• 1998

In order to discover new types of 5-hydroxytryptamine antagonists, we have devoted our attention to investigating naturally occurring compounds having anti-5HT activity in vitro. Recently, ${\gamma}$-mangostin [1,3,6,7-tetrahydroxy-2,8-bis(3-methyl-2-bytenyl)-9H-xanthen-9-one] from the fruit hull of Garcinia mangostana Linn has been shown to be a selective antagonist for 5-hydroxytryptamine$_{2A}$ receptors in smooth muscle and platelets. It is of interesting that y-mangostin which does not have a nitrogen atom, possesses marked 5-$HT_{2A}$ receptor blocking activity. The present study was undertaken to investigate the effects of ${\gamma}$-mangostin on central 5-HT receptors by using animal behavioural models. Intracerebronventricular injection of ${\gamma}$-mangostin (10-40n mol/mouse) inhibited 5-fluoro-${\alpha}$-methyltryptamin (5-FMT) (45 mg kg$^{-1}$, i.p.)-induced head-twitch response in mice in the presence or absence of citalopram (5-HT-uptake inhibitor). Neither the 5-FMT- nor the 8-hydroxy-2-( di-n-propylamino )tetralin (5-HT$_{1A}$-agonist)-induced 5-HT syndrome (head weaving and hindlimb abduction) was affected by ${\gamma}$-mangostin. The locomotor activity stimulated by 5-FMT through the activation of at-adrenoceptors did not alter in the presence of ${\gamma}$-mangostin. 5-HT-induced inositol phosphates accumulation in mouse brain slices was abolished by ketanserin. ${\gamma}$-Mangostin caused a concentration-dependent inhibition of the inositol phosphates accumulation and the binding of [$^3H$]-spiperone, a specific 5-$HT_{2A}$ receptor antagonist, to mouse brain membranes. Kinetic analysis of the [$^H3$]-spiperone binding revealed that ${\gamma}$-mangostin increased the $_{d}$ value without affecting the $B_{max}$ value, indicating the mode of the competitive nature of the inhibition by ${\gamma}$-mangostin. These results suggest that ${\gamma}$-mangostin inhibits 5-FMT-induced head-twitch response in mice by blocking 5-$HT_{2A}$ receptors not by blocking the release of 5-HT from the central neurone. ${\gamma}$-Mangostin is a promising 5-$HT_{2A}$ receptors antagonist in the central nervous system.m.

• Korean Journal of Weed Science
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• v.16 no.1
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• pp.54-63
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• 1996

This study was conducted to investigate the anatomical and ultrastructural responses of the oxyfluorfen-tolerant and -susceptible rice cultivars with barnyardgrass, a typical susceptible weed by oxyfluorfen and the herbicides having similar mode of action treatment. After the treatment of $10^{-5}M$ oxyfluorfen, the tolerant rice cultivars no showed the structural damage of leaf surface, but the susceptible rice cultivate was damaged in the wax and the susceptible barnyardgrass was even destroyed in the tissue irregularly. Also in the susceptible rice cultivars and barnyardgrass the thickness of leaf blade was greatly decreased. The anatomical change was not observed in the tolerant rice cultivars but epidermal cells, mesophyll cells and bundle sheath cells were badly broken in the susceptible rice cultivars and barnyardgrass and especially after 24 hours of the treatment the structure of susceptible rice cultivars was completely disintegrated. The irregularity of chloroplast shape and the distortion of chloroplast envelope were generally observed and the starch tended to decrease by oxyfluorfen treatment regardless of rice cultivars. Such a structural damage were appeared more badly in the susceptible rice cultivars and bamyardgrass than in the tolerant rice cultivars. By the treatment of diphenyl ether herbicides, the thickness of leaf blade greatly reduced in the order of oxyfluorfen > acifluorfen > bifenox > oxadiazon, and the susceptible rice cultivars showed more reduction than the tolerant rice cultivars. Especially, the susceptible rice cultivars showed that the leaf structure was badly broken down with damage epidermal cells and bundle sheath cells.

• Analytical Science and Technology
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• v.14 no.3
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• pp.244-252
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• 2001

A comprehensive analytical method of endocrine distruptors[i.e., nonylphenol(NP), octylphenol(OP), bis(2-ethylhexyl)phthalate(BEHP)] is fish samples was developed using two internal standards. This method employed closed culture tube extraction with dichloromethane and solvent exchange to iso-hexane and SPE(2g) aminopropyl column, followed by determination on gas chromatograph linked to mass spectrometer(GC/MS) operated in the single ion monitoring(SIM) mode. The recoveries of nonylphenol and octyphenol in the range of $0.2{\sim}20{\mu}g/g$ using 1-phenyl decanol as one internal standard were over 75%, and recovery of bis(2-ethylhexyl)phthalate in the range of $0.4{\sim}40{\mu}g/g$ using bis(2-ethylbutyl)phthalate(BEBP) as the other internal standards was showed over 102%. The present method was applied to fish samples from Korea and UK. The range of concentrations for nonylphnol(NP) and bis(2-ethylhexyl)phthalate in Korean fish were $0.02{\sim}0.06{\mu}g/g$ in 2 samples and $0.18{\sim}2.03{\mu}g/g$ in 9 samples respectively, but bis(2-ethylhexyl)phthalate(BEHP) in UK samples was found $2.99{\mu}g/g$ in just 1 sample. But octylphenol(OP) was not dected in any samples by this method. This two internal standard method provides a more precise analytical tool to investigate endocrine disruptors in a biological matrices of limited quantity.

• Journal of the Korean Society of Clothing and Textiles
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• v.11 no.2 s.24
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• pp.37-55
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• 1987

Pasul (Herein after referred to Korean-styled Pasul) to cover up the secrets, which has originated from Bool-an original mode of clothes is to put around a belt with a kind of towel. With the development of culture, it has been handed down the parts of ornamental and symbolic functions, losted its particular and original one. In general, we cannot exactly show when the Pasul has been used as a ritual dress, but, dare to maintain in this thesis, which has been used in Koguryu era. This thesis is summarized as follows: 1. The Bool, which is the first dress of all has its origin in the prehistory, and gradually has developed to a ceremonial dress with the help of man's intelligence. 2. Korean-styled Pasul has continuously been handed down from generation to generation (to adding up, from Koguryu era to Yi dynasty). Today, the color of the Pasul is known as a pink one, but I, herein, would like to refer that king Kojong in Yi dynasty had on a yellow-colored Pasul. 3. With becoming to be a form of ceremonial dress, the Bool has become to be complicated in style. For example, in the Koguryu era, the style is in the form of 'U,' and in Koryu era, it is the echelon formation tinting a pink color and weaving a mountain and flare shaped designs, and its dimension, the upper is one ja (a ja means a unit of length, 0.33 M), the lower, two ja, its length three ja. The Bool of Yi dynasty tints a pink color, and weaves a seaweeds, rices, axes and shaped designs. The Pasul which King Kojong in Yi dynasty put in, was a yellow-colored one weaving dragons and fire shaped design. 4. The Pasul is a ceremonial dress used a ritual or court dress. The purposes of wearing it are to distinguish the upper from the lower classes, to make them abide by regulations, and to respect courtesy. Accordingly, the Pasul. as the dress for special occassions does make us review the old and learn the new. 5. The reason that Pasul has been handed down are: 1) richness and fecundity. 2) symbol mark to represent classicalism. 3) to symbolize the authority by putting on it, for it is necessary to distinguish the upper from the lower classes along with the class consciousness in society. 6. On the basis of the study, the Pasul transition is to be handed down the function of the ornament and symbol. after losted its original functions, with the development of culture.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.30 no.6
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• pp.69-77
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• 2002

To acquire the dynamic response and design the controller of the airship, the longitudinal motion of the airship with respect to the vertical gust, which is the nonlinear system, was studied. The effects of the apparent mass and moment of the airship delay the dynamic response and the settling time, which are slower than those of conventional airplanes. The current object of the airship is designed to cruise at 500~1000m altitude. At that height, the atmospheric conditions are generally unstable by wind gust. In this paper, it has been studied for the case of vertical gust, since the apparent mass effects are dominant in has been studied for the case of vertical gust, since the apparent mass effects are dominant in that plane. In addition to the study of the dynamic responses of the airship, the controller was designed using the PID-controller. When the gust was applied, airship responses were recovered of equilibrium states. However, it takes too ling time for recovery and the speed of airship is reduced. So, the aim in this paper was to fasten the recovery speed and to get back the cruising velocity. The control parameters were determined from the stability mode analysis, and the control inputs were the thrust and the elevator deflection angle.

• Journal of the Korea institute for structural maintenance and inspection
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• v.15 no.5
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• pp.92-100
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• 2011

This paper describes a numerical modeling for deflection calculation using the natural frequency response that is measured acceleration response for concrete bridges. In the formulation of the dynamic deflection, the change amounts and the transformed responses about six kinds of free vibration responses are defined totally. The predicted response can be obtained from the measured acceleration data without requiring the knowledge of the initial velocity and displacement information. The relationship between the predicted response and the actual deflection is derived using the mathematical modeling that is induced by the process of a acceleration test data. In this study, in order to apply the proposed response predicted model to the integration scheme of the natural frequency domain, the Fourier Fast Transform of the deflection response is separated into the frequency component of the measured data. The feasibility for field application of the proposed calculation method is tested by the mode superposition method using the PSC-I bridges superstructures under several cases of moving load and results are compared with the actually measured deflections using transducers. It has been observed that the proposed method can asses the deflection responses successfully when the measured acceleration signals include the vehicle loading state and the free vibration behavior.

• Journal of the Korean Geotechnical Society
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• v.30 no.7
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• pp.5-15
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• 2014

Abandoned mine deposits are exposed to various physico-chemical geo-environmental hazards and disasters, such as acid mine drainage, water contamination, erosion, and landslides. This paper presents the ring shear characteristics of waste materials. The ring shear box with a rotatable O-ring was used in this study. Three tests were performed: (i) Shear stress-time relationship for given normal stress and shear speed, (ii) shear stress as a function of shear speed, and (iii) shear stress as a function of normal stress. For a given normal stress (50 kPa) and speed (0.1 mm/sec), the materials tested exhibit a strain softening behavior, regardless of drainage condition. The peak and residual shear stresses were determined for each normal stress and shear speed. The shear stress was measured when shear speed is equal to 0.01, 0.1, 1, 10, 50, 100 mm/sec or when normal stress is equal to 20, 40, 60, 80, 100, 150 kPa. From the test results, we found that the shear stress increases with increasing shear speed. The shear stress also increases with increasing normal stress. However, different types of shearing mode were observed in drained and undrained conditions. Under drained condition, particle crushing was observed from the shearing zone to the bottom of lower ring. Under undrained condition, particle crushing was observed only at the shearing zone, which has approximately 1 cm thick. It means that a significant high shear speed under undrained condition can result in increased landslide hazard.

• The Journal of Korean Academy of Prosthodontics
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• v.43 no.5
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• pp.599-610
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• 2005

Purpose: The success of the bonding between electroformed gold and ceramic is dependent on the surface treatment of the pure gold coping. The purpose of this study was to evaluate the bonding strength between the electroformed gold and ceramic with varying surface treatment. Materials and methods: A total of 32 disks,8 were using conventional ceramometal alloy, 24 were using electroforming technique as recommended by manufacturer, were prepared. 24 electroformed disks were divided 3 groups according to surface treatment, i.e. 50 microns aluminium oxide sandblasting(GES-Sand), gold bonder treatment(GES-Bond) and $Rocatec^{TM}$ system(GES-Rocatec). For control group of conventional alloy 50 microns aluminium oxide treatment was done(V-Supragold). Energy dispersive x-ray analysis and scanning electron microscope image were observed. Using universal testing machine, shear bond strength and bonding failure mode at metal-porcelain interface were measured. Results and Conclusion: The following conclusions were drawn: 1. In the energy dispersive x-ray analysis, the Au was main component in electroformed gold(99.9wt%). After surface treatment, a little amount of $Al_2O_3(2.4wt%)$ were found in GES-Sand, and $SiO_2(4wt%)$ in GES-Bond. In GES-Rocatec, however, a large amount of $SiO_2(17.4wt%)$ were found. 2. In the scanning electron microscopy, similar pattern of surface irregu larities were observed in V-Supragold and GES-Sand. In GES-Bond, surface irregularities were increased and globular ceramic particles were observed. In GES-Rocatec, a large amount of silica particles attached to metal surface with increased surface irregularities were observed. 3. The mean shear bond strength values(MPa) in order were $22.9{\pm}3.7(V-Supragold),\;22.1{\pm}3.8(GES-Bond),\;20.1{\pm}2.8(GES-Rocatec)\;and\;13.0{\pm}1.4(GES-Sand)$. There was no significant difference between V-Supragold, GES-Bond, and GES-Rocatec. (P>0.05) 4. Most bonding failures modes were adhesive type in GES-Sand. However, in V-Supragold, GES-Bond and GES-Rocatec, cohesive and combination failures were commonly observed. From the result, with proper surface treatment method electroformed gold may have enough strength compare to conventional ceramometal alloy.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.6
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• pp.1170-1174
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• 2009

Two frequency-reconfigurable antennas have been designed and combined in a space with limited volume, i.e., 40mm ${\times}$ 20mm ${\times}$ 6mm. Each antenna can be reconfigured to operate at different frequency bands depending on the state of an embedded switch, which is implemented using a PIN diode. The first antenna can be switched between 0.82GHz ${\sim}$ 0.96GHz band (GSM/ CDMA) and 1.7GHz ${\sim}$ 2.17GHz band (DCS/ PCS/ WCDMA), which are cellular bands. The second antenna can be switched between 3.4GHz ${\sim}$ 3.6GHz band (mWiMax) and 2.3GHz ${\sim}$ 2.5GHz, 5.15GHz ${\sim}$ 5.35GHz bands (WiBro/ WLAN 11a/b/g/n), which are connectivity bands. The proposed combined antenna operates both over cellular bands and connectivity bands concurrently. The choice of the operation bands is made independently by the states of the two switches.

• Plant Journal
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• v.10 no.1
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• pp.47-53
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• 2014

The national capacity of electricity of Korea was 81,737 MW and the peak demand was renewed by the record of 71,230 MW in 2012 which has been increasing since the first lighting ceremony had taken place in the Royal Palace(Kyung-Bok Goong) in 1887. Aa the counteract on the rapid increasing of the demand, Korean government is constructing and operating the high capacity nuclear and thermal power plants, however, the operating reserve on weekdays is small while those of weekends are more than 40% of capacity, so they are providing the pumped-storage power plants with the surplus electricity during weekends and operating the power plants which cost higher production price and located in the capital area with WSS (Weekly Start and Stop) mode including the Seoul Thermal Power Plant. Since the Seoul Thermal Power Plant is spending huge amount of expenses for more than 30 times of the WSS annually due to the high production cost even though it is in Seoul, the core of the demand, I chose the power plant unit #5 which was on the grid in 1969 for the case to confirm reducing 23% of the warm start-up time by applying the "Start-up time management program", and that reducing 35% of the water temperature increasing time by accelerate the increasing rate of the inlet temperature of the water circulating pump.