• 한국항행학회논문지
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• 제14권5호
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• pp.710-717
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• 2010

Quaternary 논리에서 생성 가능한 1-qudit(1-variable quantum digit) 함수는 총 256개가 존재하지만 이들 중에서 가장 유용한 것은 "0,1,2,3"의 치환에 의해 $Ax^C$+D(GF4)형의 QGFSOP 표현이 가능한 24개이다. 본 논문에서는 24개 1-qudit 함수들의 $Ax^C$+D(GF4) 연산에서 피연산자인 피승수 A와 피기수 D를 다단 종속된 치환리터럴의 제어인자로 사용하는 치환리터럴(Permutational Literals, PL) 표현과 QPL(Quaternary PL) gate를 제안하였다. 그리고 상호치환 'ab', 가산 '+D', 그리고 승산 'xA'과 같은 세 개의 PL 연산자를 사용하여 QGFSOP 표현된 24개 (1-qudit) 함수를 합성하기 위한 PL 합성법을 제안하였다. 끝으로 PL 합성법을 실현하기 위한 $Ax^C$+D(GF4) 구조와 연산회로 및 CMOS 실현 방법을 제시하였다.

• 대한의용생체공학회:의공학회지
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• 제24권3호
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• pp.159-165
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• 2003

뇌자도 측정을 위해 고감도 superconducting quantum interference device (SQUID) 자력계 및 37채널 뇌자도 측정장치를 제작하고 동작특성을 조사하였다. 자속-전압 변환계수 및 변조전압 진폭이 큰 double relaxation oscillation SQUID (DROS)를 사용함으로서 구동회로를 간단히 하였고 안정한 SQUID 동작을 실현할 수 있었다. DROS 자력계를 설계 및 제작한 결과 자력계의 평균 백색잡음은 약 3 fT/√Hz으로서 우수한 자장감도를 가짐을 확인하였다 머리의 평균곡률을 기반으로 37개의 자력계를 반구형으로 배치시켰으며, 외부잡음을 줄이기 위해 신호채널 외에 11개의 기준채널을 설치하여 소프트웨어 방법으로 합성미분계 및 적응필터링을 형성할 수 있도록 하였다 저잡음 듀아를 제작하여 동작특성을 측정한 결과 듀아 열자기 잡음이 자력계 잡음에 비해 무시할 수 있는 수준이었으며, 듀아의 용량은 30 L, 액체헬륨 증발율은 4 L/d이다. 제작된 시스템을 이용하여 청각유발 신호를 측정하고, 디지털 신호처리 및 전류원 국지화 프로그램을 구성하여 전류원의 위치를 추정함으로서 개발된 시스템을 뇌자도 측정에 활용하였다.

• 한국초전도ㆍ저온공학회논문지
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• 제5권1호
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• pp.21-26
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• 2003

We designed and constructed a multichannel superconducting quantum interference device (SQUID) magnetometer system to measure magnetic fields from the human brain. We used a new type of SQUID, the double relaxation oscillation SQUID (DROS). With high flux-to-voltage transfers of the DROS, about 10 times larger than the dc SQUIDs, simple flux-locked loop circuits could be used for SQUID operation. Also the large modulation voltage of the DROS, typically being 100 $mutextrm{V}$, enabled stable flux-locked loop operation against the thermal offset voltage drift of the preamplifier. The magnetometers were fabricated using the Nb/AlOx/Nb junction technology. The SQUID system consists of 37 signal magnetometers, distributed on a semispherical surface, and 11 reference channels were installed to pickup background noises. External feedback was used to eliminate the magnetic coupling with the adjacent channels. The liquid helium dewar has a capacity of 29 L and boil-off rate of about 4 L/d with the total 48 channel insert. The magnetometer system has an average noise level of 3 fT/√Hz at 100 Hz, inside a shielded loon, and was applied to measure auditory-evoked fields.

• 한국초전도학회:학술대회논문집
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• 한국초전도학회 1999년도 High Temperature Superconductivity Vol.IX
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• pp.27-32
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• 1999

We developed a 40-channel superconducting quantum interference device (SQUID) system for neuromagnetic measurements. The main features of the system are use of double relaxation oscillation SQUID (DROS), and planar gradiometer for measuring tangential field components. The DROSS with high flux-to-voltage transfers enabled direct readout of the SQUID output by room-temperature electronics and simple flux-locked loop circuits could be used for SQUID operation. The pickup coil is an integrated first-order planar gradiometer with a baseline of 40 mm. The average noise of the 40 channels is around 1.2 fT/cm/${\sqrt{Hz}}$ at 100 Hz, corresponding to the field noise of 5 fT/${\sqrt{Hz}}$ at 100 Hz, operated inside a magnetically shielded room. The 40-Channel system was applied to measure auditory-evoked neuromagnetic fields.

• Progress in Superconductivity
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• 제2권1호
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• pp.20-26
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• 2000

A 40-channel superconducting quantum interference device (SQUID) system was constructed for measuring neuromagnetic fields. Main features of the system are the use of double relaxation oscillation SQUIDs (DROSs), and planar gradiometers measuring magnetic field components tangential to the head surface. The DROSs with high flux-to-voltage transfers enabled direct readout of the SQUID output by room-temperature dc preamplifiers and simple flux-locked loop circuits could be used for SQUID operation. The pickup coil is an integrated first-order planar gradiometer with a baseline of 40 mm. Average noise level of the 40 channels is around 1.2 $fT/cm/{\surd}Hz$ at 100 Hz, corresponding to a field noise of 5 $fT/{\surd}Hz$, operated inside a magnetically shielded room. The SQUID insert was designed to have low thermal load, minimizing the loss of liquid helium. The constructed system was applied to measure auditory-evoked neuromagnetic fields.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2008년도 International Symposium on Remote Sensing
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• pp.220-223
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• 2008

A camera system for the satellite application performs the mission of observation by measuring radiated light energy from the target on the earth. As a development stage of the system, the signal level analysis by estimating the number of electron collected in a pixel of an applied CCD is a basic tool for the performance analysis like SNR as well as the data path design of focal plane electronic. In this paper, two methods are presented for the calculation of the number of electrons for signal level analysis. One method is a quantitative assessment based on the CCD characteristics and design parameters of optical module of the system itself in which optical module works for concentrating the light energy onto the focal plane where CCD is located to convert light energy into electrical signal. The other method compares the design\ parameters of the system such as quantum efficiency, focal length and the aperture size of the optics in comparison with existing camera system in orbit. By this way, relative count of electrons to the existing camera system is estimated. The number of electrons, as signal level of the camera system, calculated by described methods is used to design input circuits of AD converter for interfacing the image signal coming from the CCD module in the focal plane electronics. This number is also used for the analysis of the signal level of the CCD output which is critical parameter to design data path between CCD and A/D converter. The FPE(Focal Plane Electronics) designer should decide whether the dividing-circuit is necessary or not between them from the analysis. If it is necessary, the optimized dividing factor of the level should be implemented. This paper describes the analysis of the electron count of a camera system for a satellite application and then of the signal level for the interface design between CCD and A/D converter using two methods. One is a quantitative assessment based on the design parameters of the camera system, the other method compares the design parameters in comparison with those of the existing camera system in orbit for relative counting of the electrons and the signal level estimation. Chapter 2 describes the radiometry of the camera system of a satellite application to show equations for electron counting, Chapter 3 describes a camera system briefly to explain the data flow of imagery information from CCD and Chapter 4 explains the two methods for the analysis of the number of electrons and the signal level. Then conclusion is made in chapter 5.

• 대한금속재료학회지
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• 제49권9호
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• pp.732-738
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• 2011

Silicon oxide thin films were deposited by using a plasma-enhanced chemical-vapor deposition technique to investigate the light emission properties. The photoluminescence characteristics were divided into two categories along the relative ratio of the flow rates of $SiH_4$ and $N_2O$ source gases, which show light emission in the broad/visible range and a light emission peak at 380 nm. We attribute the broad/visible light emission and the light emission peak to the quantum confinement effect of nanocrystalline silicon and the Si=O defects, respectively. Changes in the photoluminescence spectra were observed after the post-annealing processes. The photoluminescence spectra of the broad light emission in the visible range shifted to the long wavelength and were saturated above an annealing temperature of $900^{\circ}C$ or after 1 hour annealing at $970^{\circ}C$. However, the position of the light emission peak at 380 nm did not change at all after the post-annealing processes. The light emission intensities at 380 nm initially increased, and decreased at annealing temperatures above $700^{\circ}C$ or after 1 hour annealing at $700^{\circ}C$. The photoluminescence behaviors after the annealing processes can be explained bythe size change of the nanocrystalline silicon and the density change of Si=O defect in the films, respectively. These results support the possibility of using a silicon-based light source for Si-optoelectronic integrated circuits and/or display devices.