• 한국정밀공학회지
• /
• 제9권2호
• /
• pp.22-28
• /
• 1992

This paper is studied about the method to measure the fine scratches on the mirror surfaces, such as the silicon wafer and magnetic memory disk by the optical measuring method. The theoretical background of this analysis is based upon the light scattering theory developed by Beckmann. In this analysis, the roughness in fine scratches is not considered because the aberage roughness is very small compared with the size of fine scratches. Empasis is on quantilaive method of fine scratches by non-contact method. Experiments are followed by the image processing system attached to the CCD Camera. As a results, I propose the new method to measure the size of the fine scratches from the parameters obtained by the computer simulation and experiments.

• 천문학논총
• /
• 제32권1호
• /
• pp.117-121
• /
• 2017

We show Akari data, Herschel data and data from the SCUBA2 camera on JCMT, of molecular clouds. We focus on pre-stellar cores within the clouds. We present Akari data of the L1147-1157 ring in Cepheus and show how the data indicate that the cores are being externally heated. We present SCUBA2 and Herschel data of the Ophiuchus region and show how the environment is also affecting core evolution in this region. We discuss the effects of the magnetic field in the Lupus I region, and how this lends support to a model for the formation and evolution of cores in filamentary molecular clouds.

• 한국생산제조학회지
• /
• 제23권3호
• /
• pp.266-272
• /
• 2014

This study proposes a closed-loop shaping control method with $H_{\infty}$ optimization for optical image stabilization (OIS) in mobile phone cameras. The image stabilizer is composed of a horizontal stage constrained by ball bearings and actuated by the magnetic force from voice coil motors. The displacement of the stage is measured by Hall effect sensors. From the OIS frequency response experiment, the transfer function models of the stage and Hall effect sensor were identified. The weight functions were determined considering the tracking performance, noise attenuation, and stability with considerable margins. The $H_{\infty}$ optimal controller was executed using closed-loop shaping and limiting the controller order, which should be less than 6 for real-time implementation. The control algorithm was verified experimentally and proved to operate as designed.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2006년도 제37회 하계학술대회 논문집 B
• /
• pp.797-798
• /
• 2006

To investigate a arc behavior when the flux density linking arc current is different, two kinds of models having the different flux density with each other are proposed. Calculations of the flux density and the electromagnetic force acting on arc column using finite element method is described in this paper. And, arc behavior photographs by the high speed camera are illustrated at breaking DC 100V, 100A on the resistance load. So, the arc driving forces are compared with according to the arc types.

• 전기학회논문지
• /
• 제60권3호
• /
• pp.600-605
• /
• 2011

This paper shows field test and evaluation results for a wireless vehicle detector with anisotropic magneto-resistive (AMR) sensors. The detector consists of two AMR sensors and mechanical and electronic apparatuses. The AMR sensor senses disturbance of the earth magnetic field caused by a vehicle moving over the sensor and then produces an output indicative of the moving vehicle. In this paper, vehicle speeds are calculated by using two AMR sensors fixed on a board, with constant distance. To test and evaluate the accuracy of the detector in real traffic situations, the detector was installed on a local highway and vehicle speeds and volumes were measured both in a free running and a highly congested traffic. The measurements from the detector are compared with the reference measurements obtained from a traffic camera with the Mean Absolute Percentage Errors (MAPE), which has proved the usefulness of the detector in the field.

• 융복합기술연구소 논문집
• /
• 제2권1호
• /
• pp.43-48
• /
• 2012

Generally, in-plane position of moving object is measured referring to the reference pattern attached to the object. From optical camera to magnetic reluctance probe, there are many ways detecting a variation of the periodical pattern. In this paper, the various operating principles developed for in-plane positioning are reviewed and compared each other. And, a novel method measuring large rotation as well as x, y linear displacements is suggested, including a detailed description of the overall system layout. It is a modified version of the surface encoder, which is a robust digital measuring method. From the surface encoder, the rotation of an object is measured indirectly through a compensated input of optical servo and independently of linear displacements. So, the operating range can be extended simply by enlarging the reference pattern, without magnifying the decoding units.

• 한국산학기술학회논문지
• /
• 제15권6호
• /
• pp.3455-3459
• /
• 2014

본 논문은 전자기 발사체에서 피투사체의 높은 발사력을 위한 코일건 설계 및 실험을 다루고 있다. 현재 코일건은 전자기 발사체에 적용하기 위해 많은 연구가 진행되고 있다. 코일건은 솔레노이드 형태의 코일에 전류 인가 시, 플레밍의 오른손 법칙에 의하여 발생하는 전자기력에 의해 피투사체를 추진시키는 원리이다. 피투사체의 발사력은 코일에 흐르는 전류가 생성하는 자기력과 비례한다. 전류는 코일의 수명에 영향을 미치므로 전류의 한계점이 존재한다. 따라서, 전류의 한계점을 초과하지 않고 피투사체가 받는 자기력이 최대가 되는 코일건의 설계가 요구된다. 이를 위해 먼저 코일건의 자속밀도, 자기력을 계산하고, Onderdonk's 식을 이용하여 코일의 전류 한계점을 찾는다. 솔레노이드를 설계하기 위해서 전류 한계점을 초과하지 않는 조건을 만족하며 코일건의 자기력을 최대로 가지는 권수를 알아낸다. 설계 결과에 따라 시제품을 제작하여 피투사체의 속도를 측정하기 위한 실험을 하였다. 발사된 피투사체는 CCD 카메라를 이용하여 촬영 및 분석하였으며, 평균속도 21m/s임을 알 수 있었다. 또한, 상용 전자기 해석 소프트웨어 MAXWELL을 이용한 자속 밀도 해석값와 실험값을 비교한 결과, 오차는 약 9.5%이었다.

• Journal of Magnetics
• /
• 제19권3호
• /
• pp.248-254
• /
• 2014

The purpose of this study is to figure out how uptake counts of technetium ($^{99m}Tc$) among radioisotopes in the human body are affected if computed tomography (CT), magnetic resonance imaging (MRI) and isotope examination are performed consecutively. $^{99m}Tc$ isotope material, iodinated contrast media for CT and paramagnetic contrast media for magnetic resonance (MR) were used as experimental materials. First, $^{99m}Tc$ was added to 4 cc normal saline in a test tube. Then, 2 cc of CT contrast media such as $Iopamidol^{(R)}$ and $Dotarem^{(R)}$ were diluted with 2 cc normal saline, and 2cc of MRI contrast media such as $Primovist^{(R)}$ and $Gadovist^{(R)}$ were diluted with 2 cc normal saline. Each distributed contrast media was a total of 4 cc and included 10m Ci of $^{99m}Tc$. A gamma camera, a LEHR (Low energy high resolution) collimator and a pin-hole collimator were used for image acquisition. Image acquisition was repeated a total of 6 times and 120 frames were obtained and uptake counts of $^{99m}Tc$ were measured (from this procedure). In this study, as a result of measuring the uptake counts of $^{99m}Tc$ using the LEHR collimator, the uptake counts were less measured in all contrast media than normal saline as a reference. In particular, the lowest uptake counts were measured when $Gadovist^{(R)}$, contrast media for MRI, was used. However, the result of measuring the uptake counts of $^{99m}Tc$ using the pin-hole collimator showed higher uptake counts in all contrast media, except for $Iopamidol^{(R)}$, than normal saline as a reference. The highest uptake counts were measured particularly when $Primovist^{(R)}$, contrast media for MRI, was used. In performing the gamma camera examination using contrast media and $^{99m}Tc$, it is considered significant to check the changes in the uptake counts to improve various diagnosis values.

• Journal of Astronomy and Space Sciences
• /
• 제23권2호
• /
• pp.143-152
• /
• 2006

밝은 장주기 변광성들을 효율적으로 관측하기 위하여 충북대학교 교내에 자동관측시스템을 구축하였다. 이 시스템의 구성을 위하여 기존의 Meade사 LX200 40cm 망원경의 구동부를 개선하고, ObsTool II라는 관측프로그램에 의하여 망원경, CCD 카메라, 돔의 제어가 하나의 프로그램으로 가능하도록 구성하였다. ObsTool II는 COM(Common Object Module)을 이용하여 개발한 프로그램으로서 시스템을 구성하는 망원경이나 CCD 카메라의 기종이 바뀌어도 큰 수정 없이 시스템을 재구성할 수 있다. 또한, 이 시스템은 광전측광관측처럼 변광성, 비교성, 검토성 등을 오가는 기능을 가지고 있어 CCD의 시야에 적당한 비교성이 함께 들어오지 않더라도 관측이 가능하다. 이 논문에서 새롭게 구성한 자동관측시스템의 안정성을 검토하기 위하여 W UMa형 변광성 V523 Cas와 자기 격변변광성 TT Ari를 관측하여 그 결과를 제시하면서 본 논문에서 개발한 시스템들의 활용가능성을 토의하였다.

• 천문학회보
• /
• 제36권2호
• /
• pp.86.1-86.1
• /
• 2011

We are developing a new universal spectropolarimeter on the Domeless Solar Telescope (DST) at the Hida Observatory to realize precise spectropolarimetric observations in a wide range of wavelength in visible and near infrared. The system aims to open a new window of plasma diagnostics by using Zeeman effect, Hanle effect, Stark effect, impact polarization, and atomic polarization for measuring the external magnetic field, electric field, or an anisotropy in the excitation of the atoms. The polarimeter is a successor of formerly developed polarimeter on DST, which make possible to observe a polarization in a photospheric spectral line with polarimetric accuracy of 10-2 (Kiyohara et al. 2004). The new system consists of a 60cm aperture vacuum telescope, a high dispersion vacuum spectrograph, polarization modulator / analyzer composed of a rotating waveplate whose retardation is constant for a wide range of wavelength and Wallaston prism, and a fast and large format CCD camera or IR camera. Spectral images in both orthogonal polarizations are taken simultaneously with a frame rate of ~20Hz while the waveplate rotates continuously in a rate of 1rev./sec. Thus It takes 5 ~ 60 sec to observe polarization with accuracy of 10-3 in a wide wavelength range (400 - 1100nm). We also examined a polarimetric model of the telescope with accuracy of 10-3 to calibrate instrumental polarization on some wavelengths. In this talk, I will focus on the performance of the instrument.