• 한국인터넷방송통신학회논문지
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• 제14권5호
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• pp.223-230
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• 2014

본 논문에서는 5.8GHz ISM 대역(5.725GHz~5.825GHz)의 저가 3차원 빔 조향을 위한 단일급전 마이크로스트립 기생 배열 안테나를 설계 및 제작하였다. 안테나는 단일 급전 능동소자와 가변 리액턴스 부하를 갖는 4개의 기생소자로 구성된다. 제작된 안테나의 빔 조향 범위는 가변 리액턴스 부하의 조절에 의해 방위각 ${\Phi}=0^{\circ}$, ${\Phi}=45^{\circ}$, ${\Phi}=90^{\circ}$, ${\Phi}=135^{\circ}$에서 ${\pm}28^{\circ}$의 3차원 빔 조향을 이룰 수 있었다. 빔 조향 범위 내에서 안테나의 최대이득은 7.23dBi~9.36dBi를 가지고, -10dB 이하 반사손실대역폭은 빔 조향각도에 상관없이 항상 5.8GHz ISM 대역을 포함하였다.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2000년도 추계학술대회논문집 - 한국공작기계학회
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• pp.279-284
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• 2000

The object of this paper is to evaluate the chip breakability using the experimental equation of surface roughness, which is developed in turning by an orthogonal array method. L$\sub$9/(3$^4$) orthogonal array method, one of fractional factorial design has been used to study effects of main cutting parameters such as cutting speed, feed rate and depth of cut, on the surface roughness. The evaluation of chip breakability is used the chip breaking index(C$\sub$B/), non-dimensional parameter. And the analysis of variance (ANOYA)-test has been used to check the significance of cutting parameters. Using the result of ANOYA-test, the experimental equation of chip breakability, which consists of significant cutting parameters, has been developed. The coefficient of determination of this equation is 0.866.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2001년도 제23회 KOSCO SYMPOSIUM 논문집
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• pp.63-71
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• 2001

The objective of this work is to elucidate the details of two key factors dominating the droplet buring behavior in sprays : droplet-droplet interaction and convective flow. The combustion of a one-dimensional linear droplet array with a convective flow has been studied. A one-step, second order model was employed to simulate the chemical reaction in the combustion process. Results for droplet arrays burning at two Reynolds numbers, 50 and 100, two horizontal droplet spacings, 5 and 11 radii, and two vertical droplet spacing, 2 and 4 radii, were obtained. The results indicate the droplet burning behavior is affected by Reynolds number, droplet-droplet spacing, and the relative location of droplets in the array. Droplet-droplet interaction was found to be strong for arrays with smaller droplet spacing.

• 대한기계학회논문집B
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• 제21권1호
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• pp.15-23
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• 1997

An experimental investigation of two-dimensional steady natural convection cooling in a vertical open top cavity with conducting side walls of finite thickness is presented. The various heat-generating discrete heaters are located on one vertical wall of the cavity. When each heater dissipates different amount of power, the purpose of the work is to obtain the optimal array condition of the heaters. The four cases of non-uniform heating conditions are considered. The temperature fields in the cavity were visualized by the interferometer and local temperatures of the vertical wall were measured by thermocouples. The heaters were arranged in two configurations: flush-mounted on a vertical wall or protruding from the wall about 4.5 mm. The vertical wall was constructed out of copper or epoxy-resin sheet. Experiments have been conducted for air with constant Prandtl number(Pr=0.7), the aspect ratio of 4.6, 7.5, 9.5, power input in the range of 0.9 W ~ 4.2 W. For the enhancement of the cooling effectiveness, the upper and lower of vertical wall would give the better position for the heaters of higher heat flux.

• 한국자기학회지
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• 제15권6호
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• pp.307-310
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• 2005

요골동맥의 운동에 대한 공간적 맥진파형 특징을 얻기 위해 2차원 배열 자기터널접합(magnetic tunnel junction; MTJ) 센서를 이용하여 공간 맥진파형 진단장치(spatial pulse diagnostic apparatus; SPDA)를 설계하였다. 자극배열의 위치변동에 대한자장 분포의 변화는 2차원 자기장 유한요소해석 소프트웨어(finite element method magnetics; FEMM)를 사용하여 모의실험을 하였다. 그 결과 평행한 자극배열에서 높은 감도와 균일한 자기장 분포를 얻을 수 있다. 또한 자석배열의 공간 변위 변화는 MTJ 센서의 출력신호 변화와 비례하였다.

• Nuclear Engineering and Technology
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• 제47권2호
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• pp.196-203
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• 2015

The aim of this work is to demonstrate a method for exciting and receiving torsional and longitudinal mode guided waves with an electromagnetic acoustic transducer (EMAT) ring array. First of all, a three-dimensional guided wave simulator is developed in order to numerically analyze the propagation of the guided wave. The finite difference time domain method is used for the simulator. Second, two guided wave testing systems using an EMAT ring array are provided: one is for torsional mode (T-mode) guided wave and the other is for longitudinal mode (L-mode). The EMATs used in the both systems are the same in design. A method to generate and receive the T- and L-mode guided waves with the same EMAT is proposed. Finally, experimental and numerical results are compared and discussed. The results of experiments and simulation agree well, showing the potential of the EMAT ring array as a mode controllable guided wave transmitter and receiver.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.496-496
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• 2000

We propose a neuron computer for tracking motion of particles in multi-dimensional space. The neuron computer is constructed of neural networks and their connections, which is a simplified model of the brain. The neuron computer is assemblage of neural networks, it includes a control unit, and the actions of the unit are represented by instructions. We designed a neuron computer to recognize and predict motion of particles. The recognition unit is constructed of neuron-array, encoder, and control part. The neuron-array is a model of the retina, and particles crease an image on the array, where the image is binary. The encoder picks one particle from the array, and translates the particle's location to Cartesian coordinates, which is scaled in [0, 1] intervals. Next, the encoder picks another particle, and does same process. The ordering and reduction of complex processes are executed by instructions. The instructions are held in the control part. The prediction unit is constructed of a multi-layer neural network and a feedback loop, where real time learning is executed. The particles' future locations are forecasted by coordinate values. The neuron computer can chase maximum 100 particles that take evasions.

• Bulletin of the Korean Chemical Society
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• 제33권7호
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• pp.2200-2206
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• 2012

One-dimensional $TiO_2$ array grown on optically transparent electrode holds a promise as a photoelectrode for photoelectrochemical water splitting; however, its crystal structure is rutile, imposing constraints on the potent use of this nanostructure. To address this issue, a heterojunction with type-II band alignment was fabricated using atomic layer deposition (ALD) technique. One-dimensional core/shell structured $TiO_2$/ZnO heterojunction was superior to $TiO_2$ in the photoelectrochemical water splitting because of better charge separation and more favorable Fermi level. The heterojunction also possesses better light scattering property, which turned out to be beneficial even for improving the photoelectrochemical performance of semiconductor-sensitized solar cell.

• 에너지공학
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• 제16권3호
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• pp.113-119
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• 2007

데칸에 물을 혼합하여 일정한 크기와 간격으로 유화액적배열을 형성하여 물과의 혼합비율, 액적의 수 그리고 액적 간격 등이 연소특성에 어떠한 영향을 주는가를 고온의 연소실에서 파악하였다. 각각 10%, 20%, 30%의 물을 혼합하여 유화액적을 만든 후 일정한 크기의 액적을 각각의 서스펜더에 매달아서 일정한 간격의 액적배열을 만들어 고온에서 자발화를 시켰을 때, 점화지연, 수명시간, 전연소기간 그리고 미소폭발 등의 연소특성을 비교하였다. 대기압에서 연소실의 온도를 920 K로 하고 서스펜더의 수를 3개와 5개로 하였으며 액적배열의 간격은 $3{\sim}7\;mm$ 범위에서 1 mm 간격으로 각각 실험을 수행하였다. 본 실험을 통하여 물의 혼합비율이 높을수록, 그리고 액적배열의 간격이 넓을수록 점화지연현상이 길게 나타났으며, 수명시간은 액적의 간격이 넓을수록 짧게 나타났으며 점화지연시간과 수명시간의 합인 전연소기간은 액적의 수량이 3개인 경우가 점화지연시간이 긴 관계로 5개에 비해 길게 나타남을 확인하였다.

• 센서학회지
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• 제14권6호
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• pp.430-437
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• 2005

In this paper, we proposed a biologically inspired light-adaptive edge detection circuit based on the human retina. A saturating resistive network was suggested for light adaptation and simulated by using HSPICE. The light adaptation mechanism of the edge detection circuit was quantitatively analyzed by using a simple model of the saturating resistive element. A light-adaptive capability of the edge detection circuit was confirmed by using the one-dimensional array of the 128 pixels with various levels of input light intensity. Experimental data of the saturating resistive element was compared with the simulated results. The entire capability of the edge detection circuit, implemented with the saturating resistive network, was investigated through the two-dimensional array of the $64{\times}64$ pixels