• Bulletin of the Korean Chemical Society
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• v.33 no.3
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• pp.997-1008
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• 2012

This work provides an alternative derivation of third order response functions in four wave mixing spectroscopy of multichromophoric macromolecular systems considering only single exciton states. For the case of harmonic oscillator bath linearly and diagonally coupled to exciton states, closed form expressions showing all the explicit time dependences are derived. These expressions can provide more solid physical basis for understanding 2-dimensional electronic spectroscopy signals. For more general cases of system-bath coupling, the quantum master equation (QME) approach is employed for the derivation of multistep time evolution equations for Green function-like operators. Solution of these equations is feasible at the level of 2nd order non-Markovian QME, and the new approach can account for inter-exciton coupling, dephasing, relaxation, and non-Markovian effects in a consistent manner.

• The Journal of the Acoustical Society of Korea
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• v.13 no.3
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• pp.71-77
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• 1994

The frequency characteristics of sound radiated by a line array of bubbles in water was investigated theoretically and experimentally. In the theory we proposed an effective coupled harmonic oscillator model for a line array of bubbles treating the interaction of only adjacent bubbles as the coupling of classical harmonic oscillators. For weak coupling of bubbles that the distance between adjacent bubbles is larger than the diameter of a bubble, the pressented theoretical model shows very good agreement with the experimental results.

• Journal of information and communication convergence engineering
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• v.2 no.4
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• pp.237-242
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• 2004

In this paper, we introduce a complex systems synchronization method using hyper-chaos circuit consist of State-Controlled Cellular Neural Network (SC-CNN). We make a complex systems using SC-CNN with the n-double scroll. A complex system is created by applying identical n-double scroll or non-identical n-double scroll and Chua's oscillator with weak coupled method to each cell. Complex systems synchronization were achieved using GS(Generalized Synchronization) method between the transmitter and receiver about each state variable in the SC-CNN.

• Journal of information and communication convergence engineering
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• v.1 no.4
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• pp.217-222
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• 2003

In this paper, we introduce a hyper-chaos synchronization method using hyper-chaos circuit consist of State-Controlled Cellular Neural Network (SC-CNN). We make a hyper-chaos circuit using SC-CNN with the n-double scroll. A hyper-chaos circuit is created by applying identical n-double scroll or non-identical n-double scroll and Chua's oscillator with weak coupled method to each cell. Hyper-chaos synchronization was achieved using GS(Generalized Synchronization) method between the transmitter and receiver about each state variable in the SC-CNN.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.413-414
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• 2008

A 2.4 GHz low phase noise fully integrated LC voltage-controlled oscillator (VCO) in $0.18\;{\mu}m$ CMOS technology is presented in this paper. The VCO is optimized based on phase noise reduction. The design of the VCO uses differential varactors which are adopted for symmetry of the circuit, and consider AM-PM conversion due to a cross-coupled pair. The VCO is designed to draw 3 mA from 1.8 V supply voltage. Simulated phase noise is -137.3 dBc/Hz at 3 MHz offset. The tuning range is found to be 300 MHz range from 2.3 GHz to 2.6 GHz.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.417-418
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• 2008

A quadrature voltage controlled oscillator(QVCO) with MOS-varactors has been fabricated for X-band applications. The QVCO consists of two cross -coupled differential cores and buffer amplifiers, which has fabricated in TSMC $0.18{\mu}m$ CMOS process. The QVCO exhibits a frequency tuning range from 8.38 GHz to 10.62 GHz. The phase noise is -88 dBc/Hz at 1 MHz-offset frequency. The total bias current is 25 mA including four buffer amplifiers.

• Journal of the Korean Institute of Telematics and Electronics
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• v.8 no.1
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• pp.1-8
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• 1971

A survey meter which is used a G-M counter sensitive to beta and gamma radiation is studied. This device is completely transistorized, operated with battery, and can be read directly the 3 full-scale meter range: 2.5, 25 and 250 MR/HR respectively. The collector-coupled monostabel multivibrator consisting of a counting-rate meter circuit, and the astable blocking oscillator consisting of a dc-de converter for power supply are analyzed and derived the design dquations. To improve the resolving time of the G-M counter the device is designed to be triggered by low pulse in the order of 0.5v.

• Proceedings of the IEEK Conference
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• 2002.06b
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• pp.145-148
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• 2002

In this paper, a voltage controlled oscillator (VCO) with automatic amplitude control is designed using a 0.35${\mu}{\textrm}{m}$ CMOS process. A cross-coupled PMOS pair is used for a negative resistance to compensate for the losses in the LC resonator, and an automatic\ulcorner amplitude control function is adapted to provide constant output power independent of the Q-factor of the LC resonator. The designed VCO operates in the 200MHz to 550MHz frequency range using different external resonators. The simulated phase noise is -128 dBc/Hz at 100KHz offset from the carrier frequency of 260MHz. It dissipates 0.㎽ from a 3V power supply. The area is 300${\mu}{\textrm}{m}$ x1201${\mu}{\textrm}{m}$.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.5 no.4
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• pp.291-296
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• 2005

In this paper, we introduce a generalized synchronization method and secure communication in the State-Controlled Cellular Neural Network (SC-CNN). We make a SC-CNN using the n-double scroll. A SC-CNN is created by applying identical n-double scroll or non-identical n-double scroll and Chua's oscillator with weak coupled method to each cell. SC-CNN synchronization was achieved using GS(Generalized Synchronization) method between the transmitter and receiver about each state variable in the SC-CNN. In order to secure communication, we have synthesizing the desired information with a SC-CNN circuit by adding the information signal to the hyper-chaos signal using the SC-CNN in the transmitter. And then, transmitting the synthesized signal to the ideal channel, we confirm secure communication by separating the information signal and the SC-CNN signal in the receiver.

• Journal of information and communication convergence engineering
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• v.8 no.4
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• pp.365-369
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• 2010

In this paper, a novel notch resonator is proposed based on Rectangular Split Ring Resonator (RRSS) element. We represented the electrical characteristics for R-SRR elements coupled with microstrip line, and measured result is compared with electromagnetic simulation (HFSS) result. We also solved equivalent circuit for R-SRR element, and also discussed influences of change structural parameters of R-SRR. The size of R-SRR is the most important parameters for frequency tuning. Also we can make tunable resonator form the basic structure. This novel resonator can apply to design of tunable bandpass filter and voltage control oscillator.