• Journal of Life Science
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• v.16 no.3 s.76
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• pp.510-515
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• 2006

The influence of $N^6-benzyladenine$ (BA) on in vitro growth, chlorophyll, rubisco and rubisco activase were studied in tobacco. After 11 weeks of treatment of various concentrations of BA, the most pronounced effect on in vitro growth and chlorophyll was found at 2 ${\mu}M$ BA. Rubisco content increased with increasing concentrations of BA, but a point at 2 ${\mu}M$ BA was reached beyond which increasing concentrations of BA cause inhibition of this enzyme. Rubisco activity showed patterns of change similar to rubisco content. These data suggest that rubisco activity was associated with an amount of rubisco protein. Under the assumption that effects of BA on rubisco may be related to by rubisco activase, in addition to, its content and activity were determined. The rubisco activase content at 2 ${\mu}M$ BA was more increased than other treatments. A similar change pattern was also observed in activity of rubisco activase. These results suggest that the effects of the activation of rubisco by BA seem to be related with rubisco activase.

• Korean Journal of Food Science and Technology
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• v.26 no.1
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• pp.93-97
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• 1994

A study of physical and chemical characteristics of pigments from Rhodopseudomonas viridis DSM 133 was carried out for development of natural greenish colorant. Through visible absorption scanning, it showed three main absorption peaks at 378, 414 and 677 nm with three minor peaks at 510, 540 and 618nm, and it was shown to be greenish color. These pigments were more stabilized in alkaline solutions than in acid of between pH 6 and 9, and it was shown to be stabilized at the temperature below $40^{\circ}C$. In the presence of light and oxygen, the stability of pigments rapidly degraded, and it became unstable in the presence of metal ion such as $Fe^{3+}$ and $Al^{3+}$. But in the presence of $Cu^{2+}$ were very stable. On the result of TLC analysis, pigments were shown to be composed of four color fractions and main color fractions were F-4 and F-2.

• Korean Journal of Food Science and Technology
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• v.14 no.3
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• pp.265-270
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• 1982

An attempt was made to investigate the antioxidant activity of maltol, kojic acid, levulinic acid, furfural, 5-hydroxymethyl furfural (5-HMF), and pyrazine which had been known to be important intermediates of Maillard browning reactions. The activity of these compounds was determined by comparing induction periods of soybean oil substrates containing each compound at a 0.01M level with that of a control. The induction period was arbitrarily taken as the time in hours for a substrate to reach a peroxide value of 60meq/kg oil. The substrates and control were stored at $45.0{\pm}1.0^{\circ}C$ for 30 days. The induction periods of the control, kojic acid, furfural, 5-HMF, maltol, levulinic acid, and pyrazine were respectively 468, 592, 510, 498, 486, 450, and 402 hours. Kojic acid demonstrated considerable antioxidant activity, whereas furfural, 5-HMF, and maltol showed weak activivity. Pyrazine and levulinic acid showed pro-oxidant activity. Although the prooxidant activity of pyrazine seemed definite, that of levulinic acid appeared very weak.

• Journal of Korean Society of Transportation
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• v.34 no.6
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• pp.510-522
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• 2016

In studies involving public transport, social welfare improvement is simply explained by the increase in public transport demand. However, the increase in the demand for public transport is mostly observed by the change in the frequency of public transport service, and in-vehicle crowding in public transport has not been an object of concern. This study examines and tries to reveal the cause of the changes of the social welfare and in-vehicle crowding of the changing public transport from imposing congestion pricing. We observe that congestion pricing increases in-vehicle crowding in public transport. This predictable phenomenon is more exacerbated in case of not operating bus-only lane. It should be noted that in-vehicle crowding is more increased in suburban, but in First-best toll system it tends to get worse less than it in other congestion pricing systems. We identify that the change of in-vehicle crowding is affected by the change of proximity of the housing to workplace, the number of commuting trips, and unpredictable distortion effect of the congestion charge.

• Journal of Broadcast Engineering
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• v.19 no.4
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• pp.510-520
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• 2014

By adopting the MAC(Media Access Control) protocol which enables to pack multiple MPDUs(MAC-level Protocol Data Units) into a single PPDU(Physical Layer Protocol Data Unit), IEEE 802.11n WLAN supports high throughput. Up to now, there have been a lot of existing channel information-based A-MPDU schemes dynamically determining the number of MSDUs according to the wireless channel condition information which is sent from the receiver to sender. However, the channel information-based scheme has a serious drawback having a high system overhead due to the frequent channel feedback information. To reduce the system overhead, the proposed BA-base dynamic A-MPDU scheme simply chooses the number of MSDUs to be retransmitted by not the frequent channel feedback information but the BA signal representing whether MPSUs belonging to the A-MPDU are received or not. Through NS-2(Network Simulator-2), we found that the proposed scheme had higher throughput and lower packet error rate than the existing fixed A-MPDU scheme.

• Journal of Korean Ophthalmic Optics Society
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• v.6 no.2
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• pp.115-119
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• 2001

To research the refractive error of the eyes on the 30's employees, 510 eyes were tested by the object and subject methods. The results were as follows. 1. Among the 510 eyes, myopia is 74.4%, hyperopia is 0.9% and emmetropia is 24.7%, respectively. 2. In test, the low myopia (-0.50Dt < Spherical Equivalent ${\leq}$ -2.00Dt) is 24.1%, the middle myopia(-2.00Dt < Spherical Equivalent ${\leq}$ -6.00Dt) is 51.4%, the high myopia(-6.00Dt < Spherical Equivalent) is 14.8% and the low hyperopia(+0.50Dt < Spherical Equivalent ${\leq}$ +2.00Dt) is 1.2%, respectively. 3. In test of astigmatism, the amount of astigmatism with-the rule is 58.5%, the amount of astigmatism against-the rule is 22.6% and the amount of astigmatism with oblique is 18.9%, respectively.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.28 no.12
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• pp.941-947
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• 2017

This paper reports a fractional-N phase-locked-loop(PLL) frequency synthesizer that is implemented in a $0.35-{\mu}m$ standard CMOS process and generates a quadrature signal for an FRS terminal. The synthesizer consists of a voltage-controlled oscillator(VCO), a charge pump(CP), loop filter(LF), a phase frequency detector(PFD), and a frequency divider. The VCO has been designed with an LC resonant circuit to provide better phase noise and power characteristics, and the CP is designed to be able to adjust the pumping current according to the PFD output. The frequency divider has been designed by a 16-divider pre-scaler and fractional-N divider based on the third delta-sigma modulator($3^{rd}$ DSM). The LF is a third-order RC filter. The measured results show that the proposed device has a dynamic frequency range of 460~510 MHz and -3.86 dBm radio-frequency output power. The phase noise of the output signal is -94.8 dBc/Hz, and the lock-in time is $300{\mu}s$.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.25 no.3
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• pp.510-519
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• 2001

The tensile and fracture toughness tests have been conducted to investigate the degradations of mechanical properties induced mainly by neutron irradiations in Zr-2.5Nb CANDU pressure tube materials operated in Wolsung Unit-1. the tests were performed at room, 150, 200, 250, 300 $\^{C}$ for the irradiated and unirradiated specimens in hot cell. The specimens were directly machined from the tube retaining original curvature using specially designed electric discharge machine(EDM). From the tensile tests of the irradiated specimens, it was found that tensile strength was increased and total elongation was decreased compared to those of the unirradiated ones. The active voltages in the fracture toughness tests for the irradiated showed the discontinuous abrupt increases caused by crack jumping in lower temperature. In the crack resistance curves we found the stable crack growth in the unirradiated, whereas the unstable and three crack growth stages in the irradiated specimens due to the accumulated irradiation defects. The various fracture characteristic values in the irradiated are remarkably lower than those of the unirradiated. Through the fractography, we found in the irradiated that smaller dimple and shorter fissures than the unirradiated, and that the fractured surface had three regions that were flat, transition and slant/shear area. These can explain the difference in the crack growth characteristic values of the irradiated and the unirradiated ones.

• Korean Journal of Ichthyology
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• v.22 no.3
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• pp.201-205
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• 2010

One specimen of a natural hybrid of an Oplegnathus (Oplegnathus fasciatus $\times$ Oplegnathus punctatus) was found in Tongyeong, Korea in August 2008. We, herein, describe its morphological and genetic characteristics and compare them with those of O. fasciatus and O. punctatus. In morphology, the hybrid showed many distinctive black rounded blotches on body sides and four faint vertical bars, being in those features similar to O. punctatus. Although the counts and measurements of the hybrid mostly overlapped between O. fasciatus and O. punctatus, the Oplegnathus hybrid resembled O. punctatus in the ratio of pelvic-fin length in standard length: Oplegnathus hybrid (26.7%) was closer to O. punctatus (26.4%) than to O. fasciatus (17.2~23.6%). In genetics, as a result of analysis of 510 base pair sequences of mitochondrial DNA 16S rRNA, the hybrid was closer to O. fasciatus (d=0.000~0.010) than to O. punctatus (d=0.020). Our results suggest that the natural hybridization represented by the subject specimen occurred between an O. fasciatus female and an O. punctatus male.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.5
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• pp.510-515
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• 2011

In this paper, an artificial transmission line coupler with slotted-triangular patches, which is compact and spacesaving structure, is proposed. The proposed structure has specific features of not only convenience for adjusting the characteristic impedance and the phase of its coupled line by varying the lengths of the slots of the artificial transmission lines in designing a coupler but also the maximized coupling value at less than ${\lambda}$/4 electrical length so that it can be designed in compact and small dimensions, while conventional coupled line couplers are generally limited in compact and miniaturized designs by their ${\lambda}$/4 transmission lines. A fabricated 15 dB test-coupler at 2.4 GHz band by proposed design method shows good agreement with theory and simulation.