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51.
Hyun‐Sang Park Seon‐Beom Ji Min‐Koo Han Jae‐Sic Lee Chi‐Woo Kim Kwang‐Soo Choi 《Journal of the Society for Information Display》2009,17(8):681-686
Abstract— A new digital ambient‐light sensor system is presented which employs two linear light sensors with different sensitivities and automatically adjusts the sensitivity based on the illumination condition. The adaptation mechanism allows a very wide range of light intensity to be detected, and the input dynamic range of the system is substantially improved from 22.5 to 45.1 dB. The proposed method does not require any additional precision bits for output data. Due to the small number of the output bits and the simple conversion process, the system can be easily integrated on the display panel. 相似文献
52.
Jae Kyeong Jeong Jong Han Jeong Hui Won Yang Tae Kyung Ahn Minkyu Kim Kwang Suk Kim Bon Seog Gu Hyun‐Joong Chung Jin‐Seong Park Yeon‐Gon Mo Hye Dong Kim Ho Kyoon Chung 《Journal of the Society for Information Display》2009,17(2):95-100
Abstract— A full‐color 12.1‐in.WXGA active‐matrix organic‐light‐emitting‐diode (AMOLED) display was, for the first time, demonstrated using indium‐gallium‐zinc oxide (IGZO) thin‐film transistors (TFTs) as an active‐matrix backplane. It was found that the fabricated AMOLED display did not suffer from the well‐known pixel non‐uniformity in luminance, even though the simple structure consisting of two transistors and one capacitor was adopted as the unit pixel circuit, which was attributed to the amorphous nature of IGZO semiconductors. The n‐channel a‐IGZO TFTs exhibited a field‐effect mobility of 17 cm2/V‐sec, threshold voltage of 1.1 V, on/off ratio >109, and subthreshold gate swing of 0.28 V/dec. The AMOLED display with a‐IGZO TFT array is promising for large‐sized applications such as notebook PCs and HDTVs because the a‐IGZO semiconductor can be deposited on large glass substrates (larger than Gen 7) using the conventional sputtering system. 相似文献
53.
Wonpil Yu Jae-Yeong Lee Young-Guk Ha Minsu Jang Joo-Chan Sohn Yong-Moo Kwon Hyo-Sung Ahn 《Automation Science and Engineering, IEEE Transactions on》2009,6(4):633-640
This paper describes a concerted effort to design and implement a robotic service framework. The proposed framework is comprised of three conceptual spaces: physical, semantic, and virtual spaces, collectively referred to as a ubiquitous robotic space. We implemented a prototype robotic security application in an office environment, which confirmed that the proposed framework is an efficient tool for developing a robotic service employing IT infrastructure, particularly for integrating heterogeneous technologies and robotic platforms. 相似文献
54.
Hwan Seong Moon Jae Suk Lee Sung Wook Han Jong Wan Park Jae Hak Lee Seung Kee Yang Hyung Ho Park 《Journal of Materials Science》1994,29(6):1545-1548
Tantalum oxide film formation by plasma-enhanced chemical vapour deposition (PECVD) using TaCl5 as a source material was examined. The effects of deposition temperature on the formation, structure and electric properties of the Ta2O5 film were investigated for Al/Ta2O5/ p-Si (MTS) capacitors. The deposition rate and refractive index increased with increasing deposition temperature. It was found that the structure of Ta2O5 deposited by PECVD was amorphous as-deposited. However, crystalline -Ta2O5 of hexagonal structure was formed by a 700 °C, 1 h heat treatment in argon. Capacitance and relative dielectric constant of the PECVD Ta2O5 were found to be 2.54 fF m–2 and 23.5, respectively. The PECVD films obtained in this study have higher dielectric constants and remarkably better general film characteristics than those obtained by other deposition methods. 相似文献
55.
Md. Moklesur Rahman Heung-Gyoon Ryu 《International Journal of Communication Systems》2023,36(8):e5475
In this paper, in order to improve the received signal strength (RSS) and signal quality, three arrays of electronically steerable parasitic array radiator (ESPAR) antennas are suggested for the ultra-high frequency (UHF) radio frequency identification (RFID) communication and sensing system applications. Instead of the single antenna, the array antennas have recently been widely used in many communication systems because of their peak gains, better radiation patterns, and higher radiation efficiency. Also, there are some important issues to use the antenna array like high data rates in wireless communication systems and to better understand the many targets or sensors. In this article, a wireless sensor network (WSN) is being investigated to overcome multipath fading and interference by antenna nulling technology that can be achieved through beam control ESPAR array antennas. The proposed ESPAR array antennas exhibit higher gains like 9.63, 10.2, and 12 dBi and proper radiation patterns from one array to another. Moreover, we investigate the mutual coupling effect on the performance of array antennas with different spacing (0.5λ, 0.75λ, λ) and configurations. It is found that the worst mutual coupling reduced by −28 to −34 dB for 2 × 2 array, −3 to −43 dB for 2 × 3 array, and finally −42 dB to −51 dB due to the antenna spacing from 0.5λ to λ. Thus, these suggested antennas could effectively be applied in the WSN communication systems, internet of things (IoT) networks, and massive wireless and backscatter communication systems. 相似文献
56.
This research investigated the microdrilling characteristics of metal foils depending on the materials of the cover plates and metal foils in the cover plate-laser beam machining (c-LBM) process, which is a method to achieve better quality in metal foil machining with a given piece of equipment. Laser beam drilling using a nanosecond pulsed laser was carried out on 10-µm-thick stainless steel 304 (STS304), nickel, and copper foils with 100-µm-thick cover plates of each material. Consequently, STS304 was found to be an effective cover plate material for reducing the hole diameter and spatter deposition on metal foils. Compared to the results without using a cover plate, the average hole diameter and the area of spatter deposition decreased by up to 77% and 96%, respectively, by using the STS304 cover plate. Meanwhile, the thermal deformation of the STS304 and nickel foils was prevented by using a cover plate, while the copper foil was barely deformed even without a cover plate. Lastly, it was remarkable that the copper foil was drilled with approximately 67% lower pulse energy than the effective minimum pulse energy required to drill it by using the STS304 cover plate, resulting in a smaller hole with little spatter. 相似文献
57.
A Novel and Facile Route to Synthesize Atomic‐Layered MoS2 Film for Large‐Area Electronics 下载免费PDF全文
Stephen Boandoh Soo Ho Choi Ji‐Hoon Park So Young Park Seungho Bang Mun Seok Jeong Joo Song Lee Hyeong Jin Kim Woochul Yang Jae‐Young Choi Soo Min Kim Ki Kang Kim 《Small (Weinheim an der Bergstrasse, Germany)》2017,13(39)
High‐quality and large‐area molybdenum disulfide (MoS2) thin film is highly desirable for applications in large‐area electronics. However, there remains a challenge in attaining MoS2 film of reasonable crystallinity due to the absence of appropriate choice and control of precursors, as well as choice of suitable growth substrates. Herein, a novel and facile route is reported for synthesizing few‐layered MoS2 film with new precursors via chemical vapor deposition. Prior to growth, an aqueous solution of sodium molybdate as the molybdenum precursor is spun onto the growth substrate and dimethyl disulfide as the liquid sulfur precursor is supplied with a bubbling system during growth. To supplement the limiting effect of Mo (sodium molybdate), a supplementary Mo is supplied by dissolving molybdenum hexacarbonyl (Mo(CO)6) in the liquid sulfur precursor delivered by the bubbler. By precisely controlling the amounts of precursors and hydrogen flow, full coverage of MoS2 film is readily achievable in 20 min. Large‐area MoS2 field effect transistors (FETs) fabricated with a conventional photolithography have a carrier mobility as high as 18.9 cm2 V?1 s?1, which is the highest reported for bottom‐gated MoS2‐FETs fabricated via photolithography with an on/off ratio of ≈105 at room temperature. 相似文献
58.
Solar Cells: Multidimensional Anodized Titanium Foam Photoelectrode for Efficient Utilization of Photons in Mesoscopic Solar Cells (Small 34/2017) 下载免费PDF全文
59.
Ji Chan Park Shin Wook Kang Jeong-Chul Kim Jae In Kwon Sanha Jang Geun Bae Rhim Mijong Kim Dong Hyun Chun Ho-Tae Lee Heon Jung Hyunjoon Song Jung-II Yang 《Nano Research》2017,(3):1044-1055
A cobalt-silica hybrid nanocatalyst bearing small cobalt particles of diameter ~5 nm was prepared through a hydrothermal reaction and hydrogen reduction.The resulting material showed very high CO conversion (>82%) and high hydrocarbon productivity (~1.0 gHc·g-1cat,·h-11) with high activity (~8.5 x 10-5 molco·g-1Co·S-1) in the Fischer-Tropsch synthesis reaction. 相似文献
60.