• 대한후두음성언어의학회지
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• 제11권1호
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• pp.76-80
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• 2000

Tongue-tip trill is a sound made by the tongue tip making contract with the alveolar ridge and oscillating rapidly as sound is produced. It is an exercise used by many singers to warm up the voice and used as one of the methods of voice rehabilitation for patients who have the vocal folds scarred postoperatively and also who present with a variety of disorders, particularly hypofunction and presbyphonia. We intended to investigate the mucosal vibration of the true vocal folds on tongue-tip trill by electroglottography and to find e effective methods of tongue-tip trill. One adult male volunteer participated. Spectrography and electroglottography were checked repeatedly 15 times, more than 5 second in each times, at same pitch, in three conditions of phonation : sustained /a/ vowel, anterior trill in which tongue-tip vibrated at anterior portion of alveolar ridge just behind the anterior tooth, and posterior trill in which at palatal crest behind the transverse palatine fold We measured the first and second formant to determine indirectly the position of tongue and calculated speed quotient and the ratio of closing phase to closed phase. Speed quotients of posterior trill were higher than sustained /a/ vowel and anterior trill in 14 times. The ratio of closing phase to dosed phase of posterior trill were lower than the others in 14 times. Mucosa of true vocal folds is vibrated more effectively on posterior trill rather than sustained /a/ vowel and anterior trill. So, when tongue-tip trill is used as a method of voice rehabilitation, we suggest that posterior trill is better in producing effective mucosal vibration

• 대한기계학회논문집B
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• 제35권12호
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• pp.1309-1316
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• 2011

본 논문에서는 올리고-dT 자성입자와 측면방향 자기영동 기술을 기반으로 하는 초고속 RNA 추출칩을 소개한다. 센자성 와이어에 유도된 고구배자장에 의해 RNA가 결합된 올리고-dT 자성입자를 분리함으로써 용해된 혈액으로부터 고속으로 RNA를 추출하였다. 유속이 20 ml/h까지 자성입자를 80% 이상의 효율로 분리할 수 있었으며, 분리시간은 총 1분 이내였다. 추출된 시료로부터 단백질에 대한 RNA 흡광비율(absorbance ratio of RNA to protein: A260/A280)이 1.7 이상임을 확인하였고, 따라서 추출된 RNA가 매우 순수함을 보였다. 추출된 RNA를 사용하여 cDNA 합성과 PCR을 수행하였으며, 이로부터 개발된 초고속 RNA 추출칩이 적은 양의 시료만으로 간편하며 빠르고 정교한 RT-PCR을 수행하는데 실용적임을 확인하였다.

• 자원환경지질
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• 제46권6호
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• pp.509-520
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• 2013

본 연구에서는 Cu, Zn, Pb 총함량이 각각 최고 3350, 1220, 2240 mg/kg에 이를 정도로 높은 오염토양을 토양세척에 의해 처리하여 해당 중금속을 제거하였다. 중금속 제거효율에 영향을 미치는 중요 인자인 세척제의 종류와 농도, 세척시간, 오염토양과 세척제의 혼합비, 교반속도 등의 최적조건을 도출하였다. 세 가지 중금속을 효과적으로 제거하는 최적 세척제는 50 mM 염산, 세척시간은 30분, 오염토양과 세척제의 혼합비는 1:30 (g/mL)이었으며, 교반속도는 중금속 제거효율에 영향을 미치지 않았다. 세척제인 염산을 재사용하면 중금속 제거효율이 감소했고, 연속적으로 재사용하면 중금속이 토양에 재흡착되었다.

• 한국컴퓨터정보학회논문지
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• 제11권4호
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• pp.77-85
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• 2006

동영상 프레임의 블록 정합에 있어서 현재 프레임의 블록들 사이에는 공간적 상관성이 존재한다. 본 논문에서는 움직임 벡터의 중심 지향적 특성과 동영상 내의 공간적 상관성을 이용한 개선된 고속 블록 정합 움직임 추정 알고리즘을 제안한다. 제안하는 알고리즘은 현재 프레임의 인접한 매크로 블록들에서 예측된 움직임 벡터와 크로스-육각 탐색 패턴을 이용하여 정확한 움직임 벡터를 결정한다. 실험 결과를 통해 제안하는 알고리즘이 예측 탐색 알고리즘 (NNS)과 고속 블록 정합 알고리즘 (CHS)에 비해 탐색 속도와 화질 면에서 우수한 성능을 나타내었다. 제안하는 알고리즘을 사용하였을 때 탐색 속도 측면에서는 약 $0.1{\sim}38%$ 정도의 향상을 보였고, 화질 측면에서도 PSNR (Peak Signal Noise Ratio) 값이 약 $0.05{\sim}2.5dB$ 정도 향상되었다.

• Wind and Structures
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• 제32권5호
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• pp.471-485
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• 2021

Onshore wind turbines may experience substantially different wind loads depending on their working conditions, i.e. rotation velocity of rotor blades, incoming freestream wind velocity, pitch angle of rotor blades, and yaw angle of the wind-turbine tower. In the present study, aerodynamic loads acting on a horizontal axis wind turbine were accordingly quantified for the high tip speed ratio (TSR) at high yaw angles because these conditions have previously not been adequately addressed. This was analyzed experimentally on a small-scale wind-turbine model in a boundary layer wind tunnel. The wind-tunnel simulation of the neutrally stratified atmospheric boundary layer (ABL) developing above a flat terrain was generated using the Counihan approach. The ABL was simulated to achieve the conditions of a wind-turbine model operating in similar inflow conditions to those of a prototype wind turbine situated in the lower atmosphere, which is another important aspect of the present work. The ABL and wind-turbine simulation length scale factors were the same (S=300) in order to satisfy the Jensen similarity criterion. Aerodynamic loads experienced by the wind-turbine model subjected to the ABL simulation were studied based on the high frequency force balance (HFFB) measurements. Emphasis was put on the thrust force and the bending moment because these two load components have previously proven to be dominant compared to other load components. The results indicate several important findings. The loads were substantially higher for TSR=10 compared to TSR=5.6. In these conditions, a considerable load reduction was achieved by pitching the rotor blades. For the blade pitch angle at 90°, the loads were ten times lower than the loads of the rotating wind-turbine model. For the blade pitch angle at 12°, the loads were at 50% of the rotating wind-turbine model. The loads were reduced by up to 40% through the yawing of the wind-turbine model, which was observed both for the rotating and the parked wind-turbine model.

• 한국분말재료학회지
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• 제4권3호
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• pp.170-178
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• 1997

An investigation was performed to apply the M3/2 grade high speed steel for metal injection molding using both prealloyed and elementally blended powders. The injected samples were subjected to a debinding step in $H_2/N_2$ gas atmosphere at a ratio that affected the carbon content of the material. The carbon content ranged from 1.4wt.% to 1.43wt%. with increasing $H_2$ content up to 80% $H_2$ in $H_2/N_2$ atmosphere for the prealloyed powders. The carbon contents of the elementally blended powders exhibited 1.44wt.% and 1.62wt.% at 10% $H_2/N_2$ and 20% $H_2/N_2$ gas, respectively. This level decreased to 0.17wt.% upon increasing the $H_2$ content. The sintered density of both powders increased rapidly as the temperature reached the liquid phase forming temperature. After forming the liquid phase, the density rapidly increased to the optimum sintering temperature for the prealloyed powders, whereas the density of mixed elemental powders goes up slowly to the optimum sintering temperature. The optimum sintering temperature and density are 126$0^{\circ}C$ and 97.3% for the prealloyed powders and 128$0^{\circ}C$ and 96.9% for the elementally blended powders, respectively. The microstructure of the specimen at the optimum sintering temperature consisted of fine grains with primary carbides of MC and $M_6C$ type for the prealloyed powders. The elementally blended powders exhibited coarse grains with eutectic carbides of MC, $M_2C$ and $M_6C$ type.

• Computers and Concrete
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• 제21권2호
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• pp.139-147
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• 2018

Due to enhanced construction requirement, ready mixed concrete are being popular day by day. The current study aimed to develop ready mixed concrete using GBFS contained cement and determine its properties of fresh and hardened states. A real scale experiment was set up in a ready mixed plant for measuring workability and compressive strength. The workability was tested after mixing (within 5 minutes), 30, 60, 90, 120 and 150 minutes of the running of bulk carrier. The ready mixed carrier employed spinning motion i.e., rotating around its axis with 20 RPM and running on road with 1km/h speed. The mixing ratio of cement: sand:gravel, water to cement ratio, super plasticizer were, 1:1.73:2.47, 0.40 and 6% of cement, respectively. The chemical composition of raw material was determined using XRF and the properties of cements were measured according to ASTM standards. The experimental results confirm that the cement with composition of 6.89% of GBFS, 4% of Gypsum and 89.11% of clinker showed the good compressive strength and workability of concrete after 150 minutes of the spinning motion in bulk carrier.

• 한국지능시스템학회논문지
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• 제13권4호
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• pp.461-468
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• 2003

In a sequence of images obtained by surveillance cameras, facial regions appear very small and their colors change abruptly by lighting condition. This paper proposes a new face detection scheme, robust on complex background, small size, and lighting conditions. The proposed method is consisted of three processes. In the first step, the candidates for the face regions are selected using face color distribution and motion information. In the second stage, the non-face regions are removed using face color ratio, boundary ratio, and average of column-wise intensity variation in the candidates. The face regions containing eyes and mouth are segmented and classified, and then they are scored using their topological relations in the last step. To speed up and improve a performance the above process, a block based image segmentation technique is used. The experiments have shown that the proposed algorithm detects faced regions with more than 91% of accuracy and less than 4.3% of false alarm rate.

• Transactions on Electrical and Electronic Materials
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• 제4권2호
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• pp.35-39
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• 2003

This paper is contents on the orthorhombic crystalline calcined by the solid phase method with LiMnO$_2$ thin film structured as the result which an average pore diameter of power was 132.3${\AA}$ in porosity analysis. Voltage ranges are able to get the properties of charge and discharge for experimental results of LiMnO$_2$ thin film were 2.2V 4.3V. The current density and scan speed were 0. 1㎃/$\textrm{cm}^2$ and 0.2㎷/sec respectively. Properties of the charge and discharge are obtained by optimum experiment condition parameters. Li dense ratio of the LiMnO$_2$ thin film that discharged capacities were 87㎃h/g have been 96.9［ppm］ at 670.784［nm］ wavelength. The dense ratio of Mn analyzed to 837［ppm］ at 257.610［nm］ wavelength. It can be estimated the quality of the LiMnO$_2$ thin film as that the wrong LiMnO$_2$ thin film pulled up from cell of electrolyte and became dry it at 800$^{\circ}C$. The results of SEM and XRD were the same as that of original researchers.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제48권4호
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• pp.261-268
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• 1999

Laser-induced thermochemical etching has been recognized as a new powerful method for processing a variety of materials, including metals, semiconductors, ceramics, insulators and polymers. This study presents characteristics of direct etching for Si substrate using focused argon ion laser beam in aqueous KOH and $CCl_2F_2$ gas. In order to determine process conditions, we first theoretically investigated the temperature characteristics induced by a CW laser beam with a gaussian intensity distribution on a silicon surface. Major process parameters are laser beam power, beam scan speed and reaction material. We have achieved a very high etch rate up to $434.7\mum/sec$ and a high aspect ratio of about 6. Potential applications of this laser beam etching include prototyping of micro-structures of MEMS(micro electro mechanical systems), repair of devices, and isolation of opto-electric devices.