http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
- 中文 을 입력하시려면 zhongwen을 입력하시고 space를누르시면됩니다.
- 北京 을 입력하시려면 beijing을 입력하시고 space를 누르시면 됩니다.
RISS 인기검색어
- 검색키워드
- 저자 : 이순걸 (검색결과 223 건)
- 무료
- 기관 내 무료
- 유료
-
-
Long-baseline single-layer 2nd-order $high-T_c$ SQUID gradiometer
이순걸,강찬석,김인선,김상재,Lee Soon-Gul,Kang Chan Seok,Kim In-Seon,Kim Sang-Jae The Korean Superconductivity Society 2005 Progress in superconductivity Vol.7 No.1
We have studied feasibility of single-layer second-order $high-T_c$ SQUID gradiometers in magnetocardiography. We have measured human cardiomagnetic signals using a short-baseline (5.8 mm) single-layer second-order YBCO gradiometer in partially shielded environments. The gradiometer has an overall size of $17.6\;mm{\times}6\;mm$ and contains three parallel-connected pickup coils which are directly coupled to a step-edge junction SQUID. The gradiometer showed an unshielded gradient noise of $0.84\;pT/cm^2/Hz^{1/2}$ at 1 Hz, which corresponds to an equivalent field noise of $280\;fT/Hz^{1/2}$. The balancing factor was $10^3$. Based on the same design rules as the short-baseline devices, we have studied fabrication of 30 mm-long baseline gradiometers. The devices had an overall size of $70.2\;mm{\times}10.6\;mm$ with each pickup coil of $10\;mm{\times}10\;mm$ in outer size. As Josephson elements we made two types of submicron bridges, which are variable thickness bridge (VTB) and constant thickness bridge (CTB), from $3\;{\mu}m-wide$ and 300 nm-thick YBCO lines with a thin layer of Au on top by using a focused ion beam (FIB) patterning method. VTB was 300 nm wide, 200 nm thick, 30 nm long with Au removed and CTB 100 nm wide and 30 nm long. In temperature-dependent critical currents, $I_c(T)$, VTB showed an nonmetallic barrier-type behavior and CTB an SNS behavior. We believe that those characteristics are ascribed to naturally formed grain boundaries crossing the bridges.
-
이순걸,Lee, Sun-Geol 한국정보통신기술협회 2006 TTA저널 Vol.106 No.-
지능형 로봇의 표준화는 초기에는 소프트웨어 및 정보통신 기술과 관련된 지능형 로봇의 중점기술을 그 표준화 항목으로 선정하여 제 분야를 구체적으로 설정하여 항목별 로드맵을 작성하였다. 그러나 다수의 구성요소들로 결합되어 이루어지는 지능형 로봇의 특성에 따라 소프트웨어나 정보통신 분야에 국한되지 않고 하드웨어에 대한 표준 및 성능 뿐만 아니라 소비자의 사용과 관련될 수 있는 제반 표준화 요소에 대한 부분까지 포괄적으로 포함시키는 방향으로 구성되었고 이를 소개하고자 한다. 지능형 로봇을 조기에 실현하고 효율적으로 보급 촉진을 꾀하기 위해서는 표준화를 해야 할 기술 항목 및 그 표준화 시기를 명확하게 하고, 연구개발을 원활하고 효율적으로 추진할 필요가 있다.
-
-
-
Sources of uniform and 2nd-order gradient fields for testing SQUID performance
이순걸,Lee, Soon-Gul The Korean Superconductivity Society 2007 Progress in superconductivity Vol.8 No.2
Uniaxial square Helmholtz coils for testing SQUID sensors were designed and their field distributions were calculated. Optimum parameters for maximizing the uniform region in the Helmholtz mode were obtained for different uniformity tolerances. The coil system consists of 2 pairs of identical square loops, a Helmholtz pair for generating uniform fields and the other for the 2nd-order gradient fields in combination with the Helmholtz pair. Full expressions of the axial component of the field were calculated by using Biot-Savart's law. To understand the behavior of the field near the coil center, analytical expressions were obtained up to the 4th-order in the midplane and along the coil axis. The Helmholtz condition for generating uniform fields was calculated to be $d/{\alpha}=0.544505643$, where 2d is the inter-coil distance and $2{\alpha}$ is the side length of the coil square. Maximized uniform range can be obtained for a given nonuniformity tolerance by choosing $d/{\alpha}$ slightly lower than the Helmholtz condition. The pure second-order gradient field can be generated by subtracting the Helmholtz field from the field of the 2nd pair with equal magnitudes of the center fields of the two pairs. The coil system is useful for testing balance and sensitivity of SQUID gradiometers.
-
-
A Full-Tensor Superconducting Gravity Gradiometer System Composed of Levitation-Type Accelerometers
이순걸 한국물리학회 2019 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.75 No.3
In this paper, a superconducting gravity gradiometer system that is designed to measure full-tensor gravity gradients based on levitation-type component accelerometers without using mechanical springs is presented. All components of the gradiometer system are made of a superconducting material, niobium. Working principles are the flux quantization and the perfect diamagnetism of the superconductor. Each component of the gravity gradient tensor is obtained from the differential gravity measured by using two accelerometers, each of which is composed of a cubic test mass, a flat sensing coil, and a flat counter coil to balance the repulsive force of the sensing coil and ambient gravity. The measured signals are amplified by using superconducting quantum interference devices. The full-tensor gradiometer system consists of three perpendicularly aligned sets of gradiometers, each of which measures one diagonal and two off-diagonal components. The details of the structure of the system, the dynamics of the gradiometer, the transfer function, the common mode rejection, and the optimum conditions are discussed.
-
Single-Layer 2nd-Order High-Tc SQUID Gradiometer for Use in Unshielded Environments
이순걸,강찬석,김인선,김상재,박승문 한국물리학회 2006 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.48 No.5I
We have studied the fabrication of second-order SQUID gradiometers from single-layer high- Tc film and the feasibility of using those gradiometers in magnetocardiography. The gradiometer contains three parallel-connected pickup loops that are directly coupled to a step-edge junction SQUID with the coupling polarity of the center loop opposite to those of the two side loops. For a well-balanced gradiometer with a balancing factor of 103, we achieved an unshielded gradient noise of 0.84 pT/cm2/Hz1/2 at 1 Hz, which corresponds to an equivalent field noise of 280 fT/Hz1/2. A gradiometer with a 5.8-mm baseline successfully recorded the magnetocardic signals of a human subject, demonstrating the feasibility of using the device in biomagnetism. We have also studied the use of submicron YBCO bridges as Josephson elements of long-baseline gradiometers. The bridges were fabricated from 3-μm-wide, 300-nm-thick YBCO lines with a thin layer of Au on top by using a focused-ion-beam (FIB) patterning method. The temperature-dependent critical currents, Ic(T), and the normal state resistances, RN(T), showed SIS-type behaviors, which are believed to be due to naturally formed grain boundaries.
-
타이어 공기압 제어시스템의 개발과 그에 따른 타이어 특성에 대한 연구
이순걸,윤상천 경희대학교 산학협력기술연구원 1998 산학협력기술연구논문집 Vol.4 No.-
New concept of on-line pressure control system of tires was proposed. And the characteristics of tire for varying air pressure using the proposed system was investigated. Compressed air from a compressor that used brake torque was stored in a reservour tank and supplied with a on-off solenoid valve. A rotating air supplying device was specially designed for rotating wheels. Air was injected into or ventilated from tires through it. The electronic control unit activated the solenoid valve using PWM output with feedback input, like tire pressure, road condition and other driving input. To show the effect of pressure on the characteristics of tire, simulation device for one wheel was made using the developed system. The result of this study showed that the stiffness of tire was increased with pressure of tire and cornering force was approximated as the response of the first order system. The system response for step change of pressure showed that it was enough faster than that of cornering force.
연관 검색어 추천
이 검색어로 많이 본 자료
활용도 높은 자료
