• 한국연소학회지
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• 제17권1호
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• pp.58-65
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• 2012

The influence of magnetic field on propane and acetylene diffusion flames have been experimentally investigated using an electromagnetic system. Periodically induced magnetic field having various frequencies and duty ratios was established in square wave form. The maximum intensity and gradient of magnetic field were 1.3 T and 0.27 T/mm, respectively. The width of a propane flame was reduced up to 4.5% and the brightness was enhanced up to 25% when the magnetic field was induced. The soot emission from an acetylene flame was ceased when magnetic field was induced. The alteration of flow field, which is due to the paramagnetic characteristics of oxygen molecule, is most likely to be responsible for the change in flame size and brightness. The effect of magnetic field on diffusion flames, which competes with the gravitational effect, was more apparent from a smaller size flame. The magnetic field effect, therefore, could be important under microgravity conditions. Since the time required to alter the flow field must be finite, the magnetic field effect is likely to be less significant for a periodically oscillating magnetic field at a high frequency or having a small duty ratio.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2004년도 Proceedings of ISRS 2004
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• pp.577-580
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• 2004

To overcome with large size noise source distribution network design difficulty in interferometric radiometer system, especially for sub-Y-type array, a new on-board calibration technique using noise re-radiation is proposed in this paper. The suggested calibration technique is using noise re-radiation effect of center antenna after noise source injection from matched load. This approach is especially proper to sub-Y-type array interferometric synthetic aperture radiometer in mm-wave frequency band. Compared with noise injection network of a conventional synthetic aperture radiometer, the system mass, volume, and hardware complexity is reduced and cost-effective. Only one internal noise source, matched load, is used for injection using noise re-radiation technique a small set of sub-Y receiver channels is calibrated. Detailed calibration scenario is discussed and simulation results about noise re­radiation effect are presented.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2006년도 Proceedings of ISRS 2006 PORSEC Volume II
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• pp.535-538
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• 2006

The coastline of the Choa Phraya Rivermouth in the Upper Gulf of Thailand has been changed drastically. The western side especially at Ban Laem Sing was eroded for 400 meter in 26 years or with the rate of 15 meter per year on the average. The Metropolitan Electricity Authority has granted five years research project to us to study the efficiency of the electric pole fence as a mean to reduce the wave force and increase sedimentation rate inside for mangrove replantation. If the method works efficiently, it will be used to reclaim the coastal land loss in other areas in Thailand. The project was done since 2005 after the fence was constructed completely in October 2005. The oceanographic surveys were conducted before and after the construction in northeast monsoon season to study the impact of physical oceanographic forces on the coastline change. The sedimentation rates were measured each month. It is rather low about 2 cm/month. The subsiding rate from the load of deltaic sediment and groundwater withdraw using boring data is about 30 mm/year. The cumulative sinking rate is 55.8 cm from 1978 to 1995. We have tried to design the method of mangrove plantation in this area. The remote sensing data such as LANDSAT and aerial photos from 1987 to 2002 for 15 years were used to compute the rate of coastline change at each 50 m section along the western side of the rivermouth.

• 한국임상수의학회지
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• 제33권4호
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• pp.221-224
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• 2016

An 8 month-old male Maltese (weighing 2.0 kg) was referred with loud heart murmur at routine physical exam in local animal clinic. Electrocardiogram found left ventricular hypertrophy pattern (4.5 mV R-wave). Diagnostic imaging studies revealed the elongation of left ventricle (LV) with classic triple bumps on the main pulmonary artery, aorta and left atrium on the ventrodorsal view of radiograph. Echocardiography revealed patent ductus arteriosus (PDA) duct and continuous turbulent shunt flow (maximal velocity 4.83 m/s) between the aorta and pulmonary artery with left to right direction. The PDA in this dog was successfully closed through femoral vein (transvenous approach) using a 5 mm Amplatz$^{(R)}$ Canine Duct Occluder. To the best of author's knowledge, this is the first case of PDA occlusion treated with Amplatz Canine Duct Occluder through femoral vein.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.2063-2066
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• 2005

This paper presents an approach to detect the dielectric condition of FRP Hot Stick in EHV high voltage cable whereas shutting down the power system is not necessary. The radio frequency generating method is adopted by transmitting radio wave into the Electrodes. This instrument is small, easy to use and also inexpensive. Furthermore, the impurity level of dirt on high voltage insulator (non-ceramic type) will be analyzed by using the methods based on IEEE Std.978-1984 at 105 kV.DC. /305 mm. and OSHA Regulation 1910.269 Part J - live line tools. The frequency at 10-20 MHz is applied to FRP Hot Stick via Electrode1 and from FRP Hot Stick surface to Electrode 2. After that the results will be evaluated by testing in each condition of FRP Hot Stick, such as dry surface, hot surface, foil winding and conductor inserting. Finally, the watt loss will be examined and compared with the loss from humidity and Carbon tracking. The important components of this system are radio frequency generating unit, frequency stabilizing unit, frequency amplifier, FRP Hot Stick frequency counter, processing unit, and display unit.

• 전자공학회논문지D
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• 제34D권5호
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• pp.1-6
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• 1997

An analysis method for the electromagnetic scattering of a tE polarized plane wave from a periodic strip grating over a grounded dielectric slab is consisered from the viewpoint of reflectio ngraing problem. The strip gratings showing bragg and off-bragg balzing phenomena at the frequency of 10GHz are designed, respectively. The strip grating structure is implemented using aluminum plate (hround conductor), paraffin(dielectric material ; .xi.$_{\gamma}$=2.24) and copper (strip conductor ; 0.08mm thickness). The experimental results (reflection power) for bragg as well as off-bragg blazing phenomenon have been compared with the theoretical results and fairly good agreements between theory and experiment have been observed.ed.

• 대한한의진단학회지
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• 제12권2호
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• pp.8-17
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• 2008

Objectives: For the traditional pulse diagnosis in Oriental Medicine, not only the pulse shape in time domain, but the width, length and depth of arterial pulse also should be measured. However, conventional pulse diagnostic systems have failed to measure the spatial parameters of the arterial pulse e.g. effective length of arterial pulse in the wrist. In fact, there are many ways to measure that kind of spatial features in arterial pulsation, but among them, the method using image sensor provides relatively cheap and simple way, therefore I tested feasibility of measuring 2-dimensional pressure distribution by imaging devices. Methods: Using widely used PC cameras and dotted balloons, the subtle oscillation of skin over the radial artery was recorded continuously, and then the displacement of every dot was calculated. Consequently, the time course of that displacements shows arterial pulse wave. Results: By the proposed method I could get pressure distribution map with 30Hz sampling rate, 21steps quantization resolution, and approximately 1mm spatial resolution. With reduced quantization resolution, $3cm{\times}4cm$ view angle could be achieved. Conclusion: Although this method has some limitations, it would be useful method for detecting 2-dimensional features of arterial pulse, and accordingly, this method provides a novel way to detect 'narrow pulse', 'wide pulse', 'long pulse', 'short pulse', and their derivatives.

• Journal of information and communication convergence engineering
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• 제18권3호
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• pp.155-161
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• 2020

The fifth generation (5G) is a state-of-the-art mobile communication access technology that uses sub 6 GHz bands and mmWave. Presently, the 5G network is partially deployed along with 4G in areas with dense traffic. In the future, the demand for the 5G bandwidth may increase. Thus, it is necessary to study the coexistence between the 5G and radio systems using adjacent or same channels to eliminate the interference between radio systems and efficiently utilize the frequency. This paper analyzed the impact of 5G new radio downlink on the fixed-satellite service earth station operating at the co-channel and adjacent channel in the upper 3.7 GHz band using the Spectrum Engineering Advanced Monte Carlo Analysis Tool, which is based on the Monte Carlo method. The results of this paper can be utilized for planning the frequency allocation of 5G networks; they can also be used as a guideline for deploying 5G base stations around a fixed-satellite service earth station.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제52권9호
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• pp.418-423
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• 2003

This paper describes an electronic compass using micromachined X- and Y-axis micro fluxgate sensors which were perpendicularly aligned each other to measure X- and Y-axis magnetic fields respectively. The fluxgate sensor was composed of rectangular-ring shaped magnetic core and solenoid excitation(49 turns) and pick-up(46 turns) coils. Excitation and pick-up coil patterns which were formed opposite to each other wound the magnetic core alternatively to improve the sensitivity and to excite the magnetic core in an optimal condition with reduced excitation current. The magnetic core has DC effective permeability of ~1000 and coercive field of ~0.1 Oe. The magnetic core is easily saturated due to the low coercive field and closed magnetic path for the excitation field. To decrease the difference of induced second harmonic voltages from X- and Y-axis, excitation condition of 2.8 $V_{P-P}$ and 1.2 MHz square wave was selected. Excellent linear response over the range of -100 $\mu$T to +100 $\mu$T was obtained with 210 V/T sensitivity. The size of each micro fluxgate sensor excluding pad region was about 2.6${\times}$1.7 $mm^2$ and the power consumption was estimated to be 14 mW.W.

• 한국전기전자재료학회논문지
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• 제15권8호
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• pp.702-707
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• 2002

This paper presents a micro fluxgate sensor in printed circuit board (PCB). The fluxgate sensor consists of five PCB stack layers including one layer magnetic core and four layers of excitation and pick-up coils. The center layer as a magnetic core is made of a micro patterned amorphous magnetic ribbon and the core has a rectangular-ring shape. The amorphous magnetic core is easily saturated due to the low coercive field and closed magnetic path for the excitation field. Four outer layers as an excitation and pick-up coils have a planar solenoid structure. The chip size of the fabricated sensing element is 7.3$\times$5.7$\textrm{mm}^2$. Excellent linear response over the range of -100$\mu$T to +100$\mu$T is obtained with 540V/T sensitivity at excitation square wave of 3 $V_{p-p}$ and 360kHz. The very low power consumption of ~8mW was measured. This magnetic sensing element, which measures the lower fields than 50$\mu$T, is very useful for various applications such as: portable navigation systems, military research, medical research, and space research.h.