• 신재생에너지
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• 제1권1호
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• pp.37-43
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• 2005

High-efficiency silicon solar cells have potential applications on mobile electronics and electrical vehicles. The fabrication processes of the high efficiency cells necessitate com placated fabrication precesses and expensive materials. Ti/Pd/Ag metal contact has been used only for limited area In spite of good stability and low contact resistance because of Its expensive material cost and precesses. Screen printed contact formed by Ag paste causes a low fill factor and a high shading loss of commercial solar cells because of high contact resistance and a low aspect ratio. Low cost Ni/Cu metal contact has been formed by using a low cost electroless and electroplating. Nickel silicide formation at the interface enhances stability and reduces the contact resistance resulting In an energy conversion efficiency of $20.2\%\;on\;0.50{\Omega}cm$ FZ wafer. Tapered contact structure has been applied to large area solar cells with $6.7\times6.7cm^2$ in order to reduce power losses by the front contact The tapered front metal contact Is easily formed by the electroplating technique producing $45cm^2$ solar cells with an efficiency of $21.4\%$ on $21.4\%\;on\;2{\Omega}cm$ FZ wafer.

• Journal of Electrochemical Science and Technology
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• 제11권3호
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• pp.310-317
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• 2020

A development of disposable strip-type galactose sensor for point-of-care testing (POCT) was studied, which was constructed using screen-printed carbon electrodes. Galactose levels were determined by the redox reaction of galactose oxidase in the presence of potassium ferricyanide as an electron transfer mediator in a small sample volume (i.e., less than 1 µL). The optimal performance of biosensor was systematically designated by varying applied potential, operating pH, mediator concentration, and amount of enzyme on the electrode. The sensor system was identified as a highly active for the galactose measurement in terms of the sensitivity (slope = 4.76 ± 0.05 nA/µM) with high sensor-to-sensor reproducibility, the linearity (R² = 0.9915 in galactose concentration range from 0 to 400 µM), and response time (t_95% = <17 s). A lower applied potential (i.e., 0.25 V vs. Ag/AgCl) allowed to minimize interference from readily oxidizable metabolites such as ascorbic acid, acetaminophen, uric acid, and acetoacetic acid. The proposed galactose sensor represents a promising system with advantage for use in POCT.

• 대한인간공학회지
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• 제31권4호
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• pp.585-591
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• 2012

Objective: The aim of this study is to propose the contactless gesture-based interface on smart mobile devices for especially rhythm action games. Background: Most existing approaches about interactions of smart mobile games are tab on the touch screen. However that way is such undesirable for someone or for sometimes, because of the disabled person, or the inconvenience that users need to touch/tab specific devices. Moreover more importantly, new interaction can derive new possibilities from stranded game genre. Method: In this paper, I present a smart mobile game with contactless gesture-based interaction and the interfaces using computer vision technology. Discovering the gestures which are easy to recognize and research of interaction system that fits to game on smart mobile device are conducted as previous studies. A combination between augmented reality technique and contactless gesture interaction is also tried. Results: The rhythm game allows a user to interact with smart mobile devices using hand gestures, without touching or tabbing the screen. Moreover users can feel fun in the game as other games. Conclusion: Evaluation results show that users make low failure numbers, and the game is able to recognize gestures with quite high precision in real time. Therefore the contactless gesture-based interaction has potentials to smart mobile game. Application: The results are applied to the commercial game application.

• 한국미생물·생명공학회지
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• 제23권4호
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• pp.405-410
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• 1995

In order to screen dextranase with high dextranolytic activity from microbial origins, dextranase producing fungal isolates were isolated from soil of the Taeion area. 197 strains with dextranolytic activities were isolated, out of which 3 strains with high dextranolytic activities were selected in the first screening. A strain (GR-98) with a best dextranolytic activity was selected in the second screening. The strain was identified to be similiar Aspergillus ustus by the morphological and cultural characteristics. The optimum culture temperature and initial pH for the dextranase production of the strain was 30$\circ$C and 7.0, respectively. The optimum culture medium was composed of 2% dextran, 0.3% KNO$_{3}$, 0.05% K$_{2}$HPO$_{4}$, 0.02% MgSO$_{4}$-7H$_{2}$O, 0.05% KC1, and 2.5 $\mu$g/ml pyridoxamine, and the enzyme production was maximum when the strain was subcultured at 30$\circ$C for 7 days.

• 한국게임학회 논문지
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• 제10권2호
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• pp.11-20
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• 2010

최근 모션 센서 기반의 무선 컨트롤러 위모트(Wiimote)와 같이 다양한 인터페이스들이 등장하면서 기존의 전통적 사용자 인터페이스인 마우스, 키보드, 조이스틱과는 다른 새로운 경험을 제공하고 있다. 또한 기술의 발전으로 디스플레이 장치는 점차 고화질 및 대형화 되어가고 있으며, 타일드 디스플레이도 여러 곳에 활용되고 있다. 그러나 대형화면을 위한 새로운 인터랙션용 장비들이 새롭게 개발되고는 있지만, 타일드 디스플레이와 같은 대형 화면에서의 사용자 인터랙션의 효율성에 대한 분석 연구는 부족한 실정이다. 본 논문에서는 4개의 다양한 화면 크기와 해상도를 가진 디스플레이들이 마우스와 위모트 사용자 인터랙션에 미치는 영향에 대해 살펴보았다.

• Environmental Engineering Research
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• 제20권4호
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• pp.383-391
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• 2015

Transparent type noise barrier is a desirable facility since it provides a secure view to drivers and passengers. However, reflection from this type of barrier could annoy dwellers on the sides of the road. To reduce reflection noise by transparent type barrier, modification can be made to the shapes on the front side and hence get effects by distortion of sound transmission. To achieve this, we have conducted simulation by which the effects of patterned screens of noise barrier on high-ways were investigated. The reduction effects of reflected sounds were evaluated for swelling, swelling with curved, rectangular and V-shaped screen type barriers, compared to the planar panel. The emitting noise was generated by 6-lane road and the patterned noise barriers had shown the reduction effects, especially in swelling and swelling with curved type for middle height dwellers, and the V-shaped screen type for higher elevation dweller. The swelling-type showed a decrease of 0.7~1.2 dB, performing the best diminution effect among the tested noise barriers.

• 디지털융복합연구
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• 제16권12호
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• pp.283-292
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• 2018

우리나라가 세계 최초로 상용화한 초고화질의 UHD 방송기술과 UHD 기반 파노라마 영상기술인 UWV는 이용자의 실재감을 극대화하는 대표적인 실감영상 기술이다. 본 연구는 UHD와 UWV에 대한 이용자들의 주관적 반응을 다각도로 비교 분석함으로써 UWV의 영상품질을 체계적으로 평가하는 것을 목적으로 한다. 이를 위해 화면크기(4k x 2k, 8k x 2k)와 콘텐츠유형(스포츠영상, 풍경영상, 공연영상)에 따른 대화면 프로젝션 실험을 설계하고 UHD와 UWV에 대한 이용자의 주관적 영상품질 평가 및 만족도를 측정하였다. 연구결과, 주관적 영상품질과 만족도의 모든 항목에 있어서 UHD에 비해 UWV에 대한 이용자의 평가가 긍정적인 것으로 나타났으며, 세부 평가는 영상 콘텐츠유형에 따라 유의한 차이를 보였다. 연구결과를 바탕으로 UWV 파노라마 기술이 발전 및 상용화되는데 필요한 점들과 후속 연구 시 고려해야할 사항을 제언하였다.

• 한국산업보건학회지
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• 제6권1호
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• pp.97-108
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• 1996

A new type of passive samplers were designed and produced by authors. After evaluating the quality of activated carbon by measuring recovery rate of organic vapors and steadiness of sampling rate, activated carbon with 30 - 35 mesh produced by Company S in Korea was selected. In each passive sampler, an amount of 400 mg of the activated carbon was filled in 25-mm cassette and covered by fixed screen (or wire screen with 100 mesh). In addition to the fixed screen, a wind screen (or wire screen with 300 mesh) was also attached at outer face. The sampling rate of the new Korean passive samplers was estimated Conclusions obtained in the study are as follows. 1. Sampling rates of the newly developed Korean passive samplers were affected by sampling time. For n-hexane, sampling rates of 15- and 60-minute samples were 70.92 and 37.45 ml/min, respectively. Sampling rate of both 200- and 450-minute samples was 25.96 ml/min. It is concluded that, when passive samplers are used for measuring organic vapors, samples be collected longer than 60 minutes. 2. Sampling rate of the passive samplers was also affected by airborne concentration of organic vapors. Lower sampling rates were determined at level of 1/2 threshold limit values (TLVs) recommended by the American Conference of Governmental Industrial Hygienists (ACGIH). It is recommended that sampling rate of the passive samplers be obtained at site by measuring concentrations using both the NIOSH Method and passive samplers simultaneously. 3. When the passive samplers, which collected organic vapors, were exposed to clean air for five hours, there was no significant loss of organic vapors due to reverse diffusion. 4. When samples were stored at room temperature ($21.8{\pm}0.7^{\circ}C$) and refrigerator ($3.8{\pm}0.7^{\circ}C$), there was no significant difference in the accuracy of results. For trichloroethylene and n-hexane, accuracies were within 25 % at both temperatures until seven days. However, poor accuracy exceeding 25 % was indicated in toluene from the first day. It is recommended that samples be stored at freezing temperature below $0^{\circ}C$. 5. Sampling efficiency was significantly affected by direction of the passive samplers. Results of samplers facing wind and down, respectively, were compared. Lower amount of organic vapors were collected when the sampler was oriented down. It is recommended that, when air velocity is low in plants, the passive samplers be oriented to the wind. However, when air velocity is high, the passive samplers be oriented down.

• Bulletin of the Korean Chemical Society
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• 제35권9호
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• pp.2803-2808
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• 2014

High potential and fast electron transfer of a cathode mediator are significant factors for improving the performance of biofuel cells. This paper reports the first synthesis of a cathode redox polymer that is a coordination complex of poly (acrylic acid-vinylpyridine-acryl amide) (PAA-PVP-PAA) and [Os(4,4'-dicarboxylic acid-2,2'-bipyridine)$_2Cl_2]^{/+}$ ($E^{\circ}=0.48V$ versus Ag/AgCl). Bilirubin oxidase can be easily incorporated into this polymer matrix, which carried out the four-electron oxygen under typical physiological conditions (pH 7.2, 0.14 M NaCl, and $37^{\circ}C$). This new polymer showed an approximately 0.1 V higher redox potential than existing cathode mediators such as PAA-PVI-$[Os(dCl-bpy)_2Cl]^{+/2+}$. In addition, we suggest increasing the polymer solubility with two hydrophilic groups present in the polymer skeleton to further improve fast electron transfer within the active sites of the enzyme. The maximum power density achieved was 60% higher than that of PAA-PVI-$[Os(dCl-bpy)_2Cl]^{+/2+}$. Furthermore, high current density and electrode stability were confirmed for this osmium polymer, which makes it a promising candidate for high-efficiency biofuel cells.

• 대한후두음성언어의학회지
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• 제21권2호
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• pp.133-138
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• 2010

Background and Objectives : High-speed imaging can be useful in studies of linguistic and artistic singing styles, and laryngeal examination of patients with voice disorders, particularly in irregular vocal fold vibrations. In this study, we introduce new laryngeal imaging systems which are commercially available high speed cameras connected with a laryngoscope. Materials and Method : The laryngeal images were captured from three different types of cameras. First, the adapter was made to connect with laryngoscope and Casio EX-F1 to capture the images using $2{\times}150$ Watt Halogen light source (EndoSTROB) at speeds of 1,200 tps (frame per second)($336{\times}96$). Second, Phantom Miro ex4 was used to capture the digital laryngeal images using Xenon Nova light source 175 Watt (STORZ) at speeds of 1,920 fps ($512{\times}384$). Finally, laryngeal images were captured using MotionXtra N-4 with 250 Watt halogen lamp (Olympus CLH-250) light source at speeds of 2,000tps ($384{\times}400$) by connecting with laryngoscope. All images were transformed into the Kymograph using KIPS (Kay's image processing Software) of Kay Pentex Inc. Results: Casio EX-F1 was too small to adjust the focus and screen size was diminished once the images were captured despite of high resolution images. High quality of color images could be obtained with Phantom Miro ex4 whereas good black and white images from Motion Xtra N-4 Despite of some limitations of illumination problems, limited recording time capacity, and time consuming procedures in Phantom Miro ex4 and Motion Xtra N-4, those portable devices provided high resolution images. Conclusion : All those high speed cameras could capture the laryngeal images by connecting with laryngoscope. High resolution images were able to be captured at the fixed position under the good lightness. Accordingly, these techniques could be applicable to observe the vocal fold vibration properties in the clinical practice.