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1,100 results on '"Lee, Sang‐Young"'

212. Effects of the finite HTS film thickness on the resonant frequency of the axially symmetric TE01delta mode of a parallel plate dielectric resonator

Author

Lee, Sang Young, Kwon, H.J., Suh, J.H., Lee, J.H., Hur, Jung, and Fedorov, V.B.

Subjects
High temperature superconductivity -- Research, High temperature superconductors -- Usage, Resonators -- Testing, Yttrium barium copper oxides -- Usage, Business, Electronics, Electronics and electrical industries
Abstract

A study on the effect of the thickness of high-temperature superconductor films on the mode resonant frequency of an axially symmetric TE01delta mode of a parallel plate dielectric resonator is presented. The analysis revealed that resonant frequency changes by under 0.4% for varying film thickness when the thickness ratio to the London penetration depth is over 10^-2. The experimental values derived were verified against the calculated values of resonant frequency.

Published
1999

219. Amphiphilic Bottlebrush Polymeric Binders for High‐Mass‐Loading Cathodes in Lithium‐Ion Batteries.

Author

Kim, Nag‐Young, Moon, Junsoo, Ryou, Myeong‐Hwa, Kim, Seung‐Hyeok, Kim, Jung‐Hui, Kim, Ju‐Myung, Bang, Joona, and Lee, Sang‐Young

Subjects
RING-opening polymerization, CATHODES, LITHIUM-ion batteries, TRANSITION metal ions, BINDING agents
Abstract

In contrast to noteworthy advancements in cathode active materials for lithium‐ion batteries, the development of cathode binders has been relatively slow. This issue is more serious for high‐mass‐loading cathodes, which are preferentially used as a facile approach to enable high‐energy‐density Li‐ion batteries. Here, amphiphilic bottlebrush polymers (BBPs) are designed as a new class of cathode binder material. Using poly (acrylic acid) (PAA) as a sidechain, BBPs are synthesized through ring‐opening metathesis polymerization. The BBPs are amphiphilic in nature owing to the hydrophilic PAA sidechains and hydrophobic polynorbornene (PNB) backbones. The PNB backbone allows process compatibility with nonaqueous solvent‐based commercial cathode fabrication, while the PAA sidechain provides strong adhesion between cathode active layers and metallic current collectors. Moreover, the PAA sidechain simultaneously chelates transition metal ions dissolved from cathode active materials (LiNi0.8Mn0.1Co0.1O2 (NCM811)) particles which are chosen as a model material. Driven by the well‐balanced amphiphilicity and bottlebrush‐based structural uniqueness of the BBP binder, the resulting NCM811 cathode exhibits uniform electron/ion conduction networks and dimensional stability. Notably, a high‐mass‐loading (27 mg cm−2, corresponding to 5.2 mAh cm−2) NCM811 cathode with stable cyclability is achieved with an extremely low content (1 wt%) of the BBP binder. [ABSTRACT FROM AUTHOR]

Published
2022
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221. Use of a dielectric-loaded cylindrical cavity in measurements of the microwave surface resistances of high-Tc superconducting thin films

Author

Lee, Sang Young, Soh, B.J., Ahn, J.W., Cho, J.Y., Park, B.H., Jung, C.S., Federov, V.B., Denisov, A.G., Kim, Y.H., Hahn, T.S., Choi, S.S., Oh, B., and Moon, S.H.

Subjects
Dielectric resonators -- Research, Microwave measurements -- Analysis, High temperature superconductors -- Research, Thin films -- Research, Business, Electronics, Electronics and electrical industries
Abstract

A study was conducted on the axially symmetric TM011 mode in a dielectric-loaded cavity. The TM011 mode dielectric-loaded cavity was then introduced for microwave surface resistance measurements in high temperature superconducting thin films using a dielectric resonator. The TM011 mode dielectric-loaded cavity was found to be very sensitive to surface resistance.

Published
1997

222. Laminar morphology development and oxygen permeability of LDPE/EVOH blends

Author

Lee, Sang Young and Kim, Sung Chul

Subjects
Polyethylene -- Analysis, Ethylene vinyl alcohol -- Analysis, Permeability -- Analysis, Engineering and manufacturing industries, Science and technology, Analysis
Abstract

Morphology and oxygen barrier properties of LDPE/EVOH blends have been studied. Laminar dispersion of ethylene-vinyl alcohol copolymer (EVOH) with high oxygen barrier properties was obtained in the matrix of low density polyethylene (LDPE) when extruded through an annular blown film die. Various laminar morphologies were observed and the main factors determining the morphology of the blends were viscosity ratio of the components, processing conditions, and compatibilizer level. Oxygen permeation tests have shown that thinner and longer EVOH layers in larger numbers were more effective in reducing the oxygen permeability. The oxygen permeability of the compatibilized blend having 6 phr of LLD-g-MAH was reduced by a factor of 740. The correlation between morphology and oxygen permeability was explained as a function of the EVOH layer size (L x R) and the number of EVOH layers (N), which were closely related to the predeformed domain size ([L.sub.o] x [R.sub.o]). The high Weber number (resulted from large [L.sub.o] x [R.sub.o] and low interfacial tension) and low viscosity ratio yielded large L x R. However, small [L.sub.o] x [R.sub.o] produced high N. Experimental results of oxygen permeability were well correlated with (L x R) x N., INTRODUCTION Increasing amounts of plastic materials are replacing metal and glass for packaging. One of the most important requirements for the use of plastics in packaging is the impermeability. Ethylene-vinyl [...]

Published
1997

226. A Chemically Self‐Charging Flexible Solid‐State Zinc‐Ion Battery Based on VO2 Cathode and Polyacrylamide–Chitin Nanofiber Hydrogel Electrolyte.

Author

Liu, Chaozheng, Xu, Wangwang, Mei, Changtong, Li, Meichun, Chen, Weimin, Hong, Shu, Kim, Won‐Yeong, Lee, Sang‐young, and Wu, Qinglin

Subjects
ELECTROLYTES, SOLID state batteries, CATHODES, ENERGY density, TUNNELS, ZINC ions, POWER density, HYDROGELS
Abstract

Conventional self‐charging systems are generally complicated and highly reliant on the availability of energy sources. Herein, a chemically self‐charging, flexible solid‐state zinc ion battery (ssZIB) based on a vanadium dioxide (VO2) cathode and a polyacrylamide‐chitin nanofiber (PAM‐ChNF) hydrogel electrolyte is developed. With a power density of 139.0 W kg‐1, the ssZIBs can deliver a high energy density of 231.9 Wh kg‐1. The superior electrochemical performance of the ssZIBs is attributed to the robust tunnel structure of the VO2 cathode and the entangled network of PAM‐ChNF electrolyte, which provide efficient pathways for ion diffusion. Impressively, the designed ssZIBs can be chemically self‐charged by the redox reaction between the cathode and oxygen in ambient conditions. After oxidation for 6 h in air, the ssZIBs manifest a high discharging capacity of 263.9 mAh g‐1 at 0.2 A g‐1, showing excellent self‐rechargeability. With the assistance of a small amount of acetic acid added to the hydrogel electrolyte, the galvanostatic discharging and chemical self‐charging cycles can reach 20. More importantly, such ssZIBs are able to operate well at chemical or/and galvanostatic charging hybrid modes, demonstrating superior reusability. This work brings a new prospect for designing flexible chemically self‐charging ssZIBs for portable self‐powered systems. [ABSTRACT FROM AUTHOR]

Published
2021
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231. Nanoparticle Separation: Wood‐Derived Nanofibrillated Cellulose Hydrogel Filters for Fast and Efficient Separation of Nanoparticles (Adv. Sustainable Syst. 9/2019)

Author

Wang, Yushu, primary, Wang, Jialiang, additional, Ling, Shengjie, additional, Liang, Haiwei, additional, Dai, Ming, additional, Bai, Lulu, additional, Li, Qing, additional, Fan, Zhuangjun, additional, Lee, Sang‐Young, additional, Yu, Haipeng, additional, Liu, Shouxin, additional, Wang, Qingwen, additional, Liu, Yixing, additional, Li, Jian, additional, Sun, Tianmeng, additional, and Chen, Wenshuai, additional

Published
2019
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233. Wood‐Derived Nanofibrillated Cellulose Hydrogel Filters for Fast and Efficient Separation of Nanoparticles

Author

Wang, Yushu, primary, Wang, Jialiang, additional, Ling, Shengjie, additional, Liang, Haiwei, additional, Dai, Ming, additional, Bai, Lulu, additional, Li, Qing, additional, Fan, Zhuangjun, additional, Lee, Sang‐Young, additional, Yu, Haipeng, additional, Liu, Shouxin, additional, Wang, Qingwen, additional, Liu, Yixing, additional, Li, Jian, additional, Sun, Tianmeng, additional, and Chen, Wenshuai, additional

Published
2019
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241. Work function-tailored graphene via transition metal encapsulation as a highly active and durable catalyst for the oxygen reduction reaction

Author

Sharma, Monika, primary, Jang, Jue-Hyuk, additional, Shin, Dong Yun, additional, Kwon, Jeong An, additional, Lim, Dong-Hee, additional, Choi, Daeil, additional, Sung, Hukwang, additional, Jang, Jeonghee, additional, Lee, Sang-Young, additional, Lee, Kwan Young, additional, Park, Hee-Young, additional, Jung, Namgee, additional, and Yoo, Sung Jong, additional

Published
2019
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