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843 results on '"Jung, Ji‐Won"'

155. Lithium–Air Batteries: Air-Breathing Challenges and Perspective

Author

Kang, Jin-Hyuk, primary, Lee, Jiyoung, additional, Jung, Ji-Won, additional, Park, Jiwon, additional, Jang, Taegyu, additional, Kim, Hyun-Soo, additional, Nam, Jong-Seok, additional, Lim, Haeseong, additional, Yoon, Ki Ro, additional, Ryu, Won-Hee, additional, Kim, Il-Doo, additional, and Byon, Hye Ryung, additional

Published
2020
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172. CuInSe 2 -Based Near-Infrared Photodetector.

Author

Kim, Sung-Tae, Yoo, Ji-Seon, Lee, Min-Woo, Jung, Ji-Won, and Jang, Jae-Hyung

Subjects
OPTICAL fiber communication, PHOTODETECTORS, QUANTUM efficiency, THIN films
Abstract

Near-infrared (NIR) photodetectors have interesting roles in optical fiber communications and biomedical applications. Conventional NIR photodetectors have been realized using InGaAs and Ge, of which the cut-off wavelengths exceed 1500 nm. Si-based photodetectors exhibit limited external quantum efficiency at wavelengths longer than 1000 nm. By synthesizing a CuInSe2 compound on a glass substrate, photodetectors that can detect optical wavelengths longer than 1100 nm have been realized in this study. The bandgap energies of the CuInSe2 thin films were tuned by varying the Cu/In ratio from 1.02 to 0.87. The longest cut-off wavelength (1309 nm) was obtained from a CuInSe2 thin film having a Cu/In ratio of 0.87. The responsivity of the photodiode was measured under the illumination of a 1064 nm laser light. The photo responses exhibited linear response up to 2.33 mW optical illumination and a responsivity of 0.60 A/W at −0.4 V. [ABSTRACT FROM AUTHOR]

Published
2022
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173. A highly miniaturized active 90-degree power combiner MMIC employing CE and CC circuits

Author

Park, Young-Bae, Yun, Young, Kang, Suk-Youb, Kang, In-Ho, Jung, Ji-Won, Park, Kyu-Ho, and Anh, Kwang-Ho

Subjects
Microwave integrated circuits -- Research, Bipolar transistors -- Research, Signal processing -- Equipment and supplies, Signal processing -- Research, Business, Electronics and electrical industries, Engineering and manufacturing industries, Telecommunications industry
Abstract

A highly miniaturized monolithic microwave integrated circuit using common-emitter and common-collector circuits is fabricated for signal mixing. The active 90-degree power combiner's performance is superior to a passive combiner at S-band.

Published
2009

174. A highly integrated HBT down-converter MMIC employing optimally designed spiral inductor filters

Author

Yun, Young, Kang, In-Ho, and Jung, Ji-Won

Subjects
Microwave integrated circuits -- Design and construction, Bipolar transistors -- Usage, Microwave filters -- Design and construction, Business, Electronics and electrical industries, Engineering and manufacturing industries, Telecommunications industry
Abstract

A highly integrated down-converter monolithic microwave integrated circuit using heterojunction bipolar transistors for Ku-band commercial wireless communication systems is designed. The circuit includes a mixer, a filter, an amplifier, and input/output matching circuits.

Published
2008

175. Acoustic intruder detection system for home security

Author

Choi, Young-Keun, Kim, Ki-Man, Jung, Ji-Won, Chun, Seung-Yong, and Park, Kyu-Sik

Subjects
Fourier transformations -- Research, Data encryption chips -- Research, Algorithms -- Research, Data security device, Algorithm, Business, Electronics and electrical industries, Engineering and manufacturing industries
Abstract

This paper propose a new algorithm to detect the intruder in room. The basic idea of the proposed method is to estimate the variation of features of the room acoustic transfer function(RTF). The room transfer function is computed by cross-correlation method. There are some methods to measure the RFT. For example there are the image methods, ray tracing method to measure actually the RFT. In this we estimated RTF using white Gaussian noise that is broadband signal. It is important to extract feature vectors. Feature extraction is the process of computing a numerical representation. We used various features to detect intruder. The features based on the Short Time Fourier Transform (STFT) and the zero-crossing rates were used. Several simulations and actually tests show that the proposed method provides good performance for intruder detection. Index Terms--intruder detection, feature, room transfer function, Short Time Fourier Transform

Published
2005

176. Performance analysis of extended OQPSK carrier phase recovery algorithm in satellite channel

Author

Jung, Ji Won and Kim, Myung Sup

Subjects
Satellite communications -- Testing, Business, Electronics and electrical industries, Engineering and manufacturing industries
Abstract

This paper proposes a new extended decision-directed decision-estimated phase recovery algorithm based on maximum likelihood parameter estimation for OQPSK (Offset QPSK). In this scheme, comparing to conventional one, the data dependent noise of phase recovery loop is reduced by inserting the filter with 2 taps to inphase and quadrature channel respectively before the phase detector. Proposed scheme is compared to the conventional QPSK scheme in aspect to BER(Bit Error Rate) and phase error for roil-off factors of baseband filter, output backoffs of nonlinear satellite channel, and loop bandwidth.

Published
2000

187. A Critical Review on Functionalization of Air‐Cathodes for Nonaqueous Li–O2 Batteries.

Author

Balaish, Moran, Jung, Ji‐Won, Kim, Il‐Doo, and Ein‐Eli, Yair

Subjects
*LITHIUM-air batteries, *SURFACE chemistry, *ELECTRIC batteries, *CHEMICAL stability, *SURFACE structure, *NONAQUEOUS phase liquids, *NITRIDES, *METALLIC oxides
Abstract

This review reports on the most updated technological aspects of Li–air battery cathode materials. It provides the reader with recent developments, alongside critical views. The requirements for air‐cathodes, as well as the classification and characterization of carbon‐based and carbon‐free air cathodes, are listed. The effects of two major substituent groups of materials, namely carbon and advanced materials (metals, metal‐oxides, metal‐carbides, and metal‐nitrides) aimed at replacing carbon, are discussed in terms of their chemical and electrochemical stability. The report covers aspects of surface chemistry and structure influence on the electrolyte and discharge products stability. The review also reports on the efforts to suppress side reactions and deterioration of the polymeric binders (if a composite electrode is being considered). This is recognized as a means to enhance Li–air battery performance. The report concludes with an outlook and perspective, providing the readers with some insight on other factors and their impact on the long road toward a viable air‐cathode suitable for Li–air battery operations. [ABSTRACT FROM AUTHOR]

Published
2020
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197. Clinically-Relevant Rapamycin Treatment Regimens Enhance CD8+Effector Memory T Cell Function In The Skin and Allow their Infiltration into Cutaneous Squamous Cell Carcinoma

Author

Jung, Ji-Won, primary, Veitch, Margaret, additional, Bridge, Jennifer A., additional, Overgaard, Nana H., additional, Cruz, Jazmina L., additional, Linedale, Richard, additional, Franklin, Michael E., additional, Saunders, Nicholas A., additional, Simpson, Fiona, additional, Frazer, Ian H., additional, Steptoe, Raymond J., additional, and Wells, James W., additional

Published
2018
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