• Preventive Nutrition and Food Science
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• v.3 no.4
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• pp.334-338
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• 1998

Kale(Brassica oleracea var. acephala) is one of Cruciferous vegetables that is closely related to the wild ancestral form of cabbabe. The ethanol extract of kale which contains the active compoundsss under Salmonella assay system was fractionated with chloroform to collect the nonpolar solvent soluble compounds, and then further fractionation was carried out by silica gel column chromatography. Among kale extracts separated by silical gel column chromatography, the fractions of 4, 5 and 6 exhibited strong antimutagenic activities. The major active compounds from the fraction were identified as chlorophyll derivatives by the analysis with HPLC-fritp-MS. The molecular weights of each chlorophyll derivatives in the sample were acquired from the peaks of positive ion atomosphere pressure chemical ionization (APCI) mas spectrometry.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2010.10a
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• pp.362-367
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• 2010

This paper deals with the correlation between the interior noise and the floor vibration of the train from rolling, impulse and friction in Busan Metro line 3. The correlation is verified by sound and vibration measurement causing friction between the railway and the wheel. If ANC(Active Noise Control) system can reduce 5 dB in below 500 Hz, the sound pressure level of the whole band pass can be reduced about 1.8-4.8 dB in squeal noise. Curve squeal noise is the intense high frequency tonal that can occur when a railway vehicle transverses a curve. The frequency range is from around 500 to almost 20,000 Hz, with noise levels up to about 15 dB in curve.

• International Journal of Aeronautical and Space Sciences
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• v.17 no.3
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• pp.315-323
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• 2016

This paper deals with experimental investigation of active flow control via synthetic jets using an unmanned combat air vehicle (UCAV) planform. Fourteen arrays of synthetic jets, mounted along both leading edges, were fully or partially activated to increase aerodynamic efficiency and reduce pitch-up moment. The measurements were carried out using a six-component external balance, a pressure scanner, and tuft flow visualization. It was observed that aerodynamic efficiency (L/D) and pitching moment were clearly affected by the location of jets. In particular, inboard and outboard actuation could effectively increase L/D. Moreover, inboard actuation showed a reduction in the pitch-up, even more than that generated by the full actuation. These results suggest that inboard actuation not only effectively increases L/D but also reduces the pitch-up using only a few actuators.

• Journal of the Korean Society for Precision Engineering
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• v.19 no.5
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• pp.168-175
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• 2002

The hydraulic acoustic attenuator fur an automotive active suspension system is so highly nonlinear and of high order that the analysis in time-domain has been performed quite little. In this paper, a state-space representation of the dynamics for a hydraulic attenuator was presented utilizing the electrical analogy. And the results of experiment were compared with those of simulation to validate the state-space model proposed. The comparison revealed that the state-space model proposed is practically applicable to estimate the dynamic responses of the hydraulic attenuator in time-domain.

• Proceedings of the KIEE Conference
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• 1989.07a
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• pp.333-334
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• 1989

Electrically active part of the piezoelectric sound element is a ceramic thin circular disk cemented to a metal base plate (using a type of thermosetting epoxy). The active part is a thin lead zirconate titanate disk (PZT). The piezoelectric sound element is so dimensioned that its basic resonance frequency is approximately if the center of the audible frequency band: This frequency is mainly determined by the geometry and the sort of the metal base plate materials. In this study, four kinds of PZT ceramic and two classes of thin metal base plate were prepared. It is observed that dielectric and pizoelectric properties relate to acoustical properties (particularly sound pressure level).

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.178.4-178
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• 2001

In this paper a self-tuning gain-scheduled skyhook control for semi-active suspension systems is investigated. The dynamic characteristics of a continuously variable damper including electro-hydraulic pressure control valves is analyzed. A 2-d.o.f. time-varying quarter-car model that permits variations in sprung mass and suspension spring coefficient is considered. The self-tuning skyhook control algorithm proposed in this paper requires only the measurement of body acceleration. The absolute velocity of the sprung mass and the relative velocity of the suspension deflection are estimated by using integral filters. The skyhook gains are gain-scheduled in such a way that the body acceleration and the dynamic tire force are optimized. An ECU prototype ...

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.9
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• pp.172-176
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• 2013

This paper presents a modified filtered-x least mean square (FxLMS) algorithm to improve the stability of active noise control (ANC) system in realistic environment. A real-time ANC system employing modified FxLMS is designed and implemented on digital signal processor (DSP) board. The ANC system is evaluated for cancelling various tonal frequency noises in the range from 100 to 500 Hz and the performance is measured in terms of sound pressure level (SPL) attenuation. Experiment results show that a quiet zone with maximum 20 dB SPL attenuation can be generated around the location of error microphone.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.174-174
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• 2012

The nature of feed gas is essential for the active species formed in the nonthermal plasma jets, which would induce various biological phenomena. We investigated the different physiological effects of atmospheric pressure soft-plasma jets on Esherichia coli and blood cells according to the feed gas. Cell death rate, growth curve, membrane molecular changes and induced genes were examined. The relationship between cellular reactions and active species generated by discharge will be discussed.

• Proceedings of the Korean Biophysical Society Conference
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• 2002.06b
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• pp.18-18
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• 2002

Nitrogenase, comprised of the MoFe and Fe proteins, catalyzes the reduction of dinitrogen to ammonia at ambient temperature and pressure. The MoFe protein contains two metal centers, the P-cluster (Fe8S7-8) and the FeMo-cofactor (Fe7S9：homocitrate), the substrate binding site. Despite the availability of the crystal structure of the MoFe protein, suprisingly little is known about the molecular details of catalysis at the active site, and no small-molecule substrate or inhibitor had ever been shown to directly interact with a protein-bound cluster of the functioning enzyme, until our electron-nuclear double resonance(ENDOR) study of CO-inhibited nitrogenase.(omitted)

• Journal of Institute of Control, Robotics and Systems
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• v.8 no.2
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• pp.158-166
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• 2002

A mathematical model and dynamic characteristics ova continuously variable damper for semi-active suspen- sion systems are investigated. After analyzing the geometry of a typical continuously variable damper, mathematical models fur individual components including piston, orifices, spring, and valves are first derived and then the flow equations for extension and compression strokes are investigated. To verify the developed mathematical model, the dynamic response of the model are simulated using MATLAB/SIMULINK and are compared with experimental results. The proposed model can be used not only for mechanical components design but also for control system design.