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Compact Active Integrated Antennas Embedded in LTCC Substrates for 5.8 ㎓ Wireless LAN Applications
Jinwoo Jang,Byungjun Bang,Yohan Jeong,Yongmin Seo,Yong Jee 대한전자공학회 2008 ICEIC:International Conference on Electronics, Inf Vol.1 No.1
This paper presents compact active integrated antennas embedded in low temperature co-fired ceramic substrates for 5.8-㎓ wireless LAN applications, including design, simulation, fabrication, and measurements. The active integrated antenna (AIA) measures 13㎜ × 14㎜ × 0.75 ㎜ and exhibits an effective gain improvement of 19.0 ㏈ over the range of 5.3㎓-6.0㎓, the bandwidth of 12% at 5.8㎓. AIA is highly reproducible with good tolerance, in which the output port of coplanar waveguide monopole antenna is directly connected to the gate unit of active devices (HEMT). Using low noise amplifiers (LNA) embedded in LTCC substrates and directly connecting to the passive antenna, a simple and compact RF front-end AIA receiver has been achieved.
Jang, Youn Jeong,Jang, Ji-Wook,Lee, Jaehyuk,Kim, Ju Hun,Kumagai, Hiromu,Lee, Jinwoo,Minegishi, Tsutomu,Kubota, Jun,Domen, Kazunari,Lee, Jae Sung The Royal Society of Chemistry 2015 ENERGY AND ENVIRONMENTAL SCIENCE Vol.8 No.12
<P>A gold-coupled ZnTe/ZnO-nanowire array is a new photocathode for selective CO<SUB>2</SUB> reduction to CO. At −0.7 V<SUB>RHE</SUB> under simulated 1 sun illumination, its photocurrent (−16.0 mA cm<SUP>−2</SUP>) and incident photon-to-current conversion efficiency (97%) represent the highest among reported ZnTe photocathodes for CO<SUB>2</SUB> reduction and dramatic enhancement from those of a bare electrode (−7.9 mA cm<SUP>−2</SUP>, 68%). In addition, the Au nanoparticles convert mainly-hydrogen-producing bare ZnTe/ZnO-nanowires into mainly-CO-producing photocathodes in photoelectrochemical CO<SUB>2</SUB> reduction. The remarkable effects of the Au co-catalyst originate from the formation of a Schottky junction with ZnTe to improve charge separation and to provide reaction centers for CO<SUB>2</SUB> reduction suppressing competing water reduction.</P> <P>Graphic Abstract</P><P>Au coupled ZnTe/ZnO-NW array is a new photocathode for selective CO production from CO<SUB>2</SUB>. The remarkable effects of an Au are to form of a Schottky junction with ZnTe to improve band bending and provide the reaction center for CO<SUB>2</SUB> reduction suppressing water reduction. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c5ee01445j'> </P>
Jang, Jiuk,Kim, Hyobeom,Ji, Sangyoon,Kim, Ha Jun,Kang, Min Soo,Kim, Tae Soo,Won, Jong-eun,Lee, Jae-Hyun,Cheon, Jinwoo,Kang, Kibum,Im, Won Bin,Park, Jang-Ung American Chemical Society 2020 NANO LETTERS Vol.20 No.1
<P>Tactile pressure sensors as flexible bioelectronic devices have been regarded as the key component for recently emerging applications in electronic skins, health-monitoring devices, or human-machine interfaces. However, their narrow range of sensible pressure and their difficulty in forming high integrations represent major limitations for various potential applications. Herein, we report fully integrated, active-matrix arrays of pressure-sensitive MoS<SUB>2</SUB> transistors with mechanoluminescent layers and air dielectrics for wide detectable range from footsteps to cellular motions. The inclusion of mechanoluminescent materials as well as air spaces can increase the sensitivity significantly over entire pressure regimes. In addition, the high integration capability of these active-matrix sensory circuitries can enhance their spatial resolution to the level sufficient to analyze the pressure distribution in a single cardiomyocyte. We envision that these wide-range pressure sensors will provide a new strategy toward next-generation electronics at biomachine interfaces to monitor various mechanical and biological phenomena at single-cell resolution.</P> [FIG OMISSION]</BR>
Assessing the toxic effects of accumulated arsenic on Arabidopsis thaliana
Jinwoo Jang,Yangwon Jeon,Yeonhong Kim,Geupil Jang,Youngdae Yoon 한국응용생명화학회 2024 Journal of Applied Biological Chemistry (J. Appl. Vol.67 No.-
Previous studies have reported that high pesticide and fertilizer use leads to a gradual accumulation of arsenic in soil environments. To understand the effects of arsenic on plant growth, we aimed to analyze the effect of As(III) on plant growth and development using Arabidopsis thaliana as a model plant. The results revealed that various aspects of plant growth, including seed germination and shoot development, were negatively impacted by As(III) treatment, but the effects were not significant. By contrast, root development was strongly suppressed by As(III) exposure, and the extent of suppression was dependent on the concentration of As(III) used. To gain a deeper understanding of adverse effects on root development, we examined the correlation between As(III) exposure and auxin, a key phytohormone responsible for root growth. Visualizing the auxin response in Arabidopsis roots using DR5::VEUNS and IAA2::GFP revealed that As(III) treatment suppressed auxin response in Arabidopsis roots, and this suppression was tightly correlated with the As(III) concentration. Furthermore, we used As(III)-specific bacterial cell-based biosensors to quantify the accumulation of arsenic in plants and establish a correlation with physiological changes. The inhibition of root growth was observed at 0.5 mg/g of As(III) treatment and it was correlated to 0.063 mg of As(III) per 1 g of dried plant. Although further investigations are required to fully assess the toxic effects of arsenic on the physiological properties of plants, the findings presented in this study provide valuable insights for evaluating the toxic effects of accumulated arsenic on plant growth and development.
볼의 자이로스코픽 모멘트와 원심력을 고려한 고속 볼베어링의 마찰 토크 해석 및 실험
장진우(Jinwoo Jang),장건희(Gunhee Jang) 한국소음진동공학회 2015 한국소음진동공학회 학술대회논문집 Vol.2015 No.10
A ball bearing is core component to design a rotor-bearing system. Friction loss of ball bearings is one of major energy loss in the rotor-bearing system, and predicting the friction torque of ball bearings is required to design a motor with low power consumption. Force equilibrium equations and geometric compatibility equations of a ball bearing are solved to calculate dynamic characteristics of a ball bearing. Friction torque is calculated by Palmgren and SKF ball bearing friction models with simulated contact angle result. In experiment, power loss of a motor is measured to calculate the friction torque of a ball bearing. The research shows that Palmgren and SKF ball bearing friction models are in good agreement with the experimental result, and the friction torque of a ball bearing is dominantly affected by preload and rotating speed.
Nanoparticle assemblies as memristors.
Kim, Tae Hee,Jang, Eun Young,Lee, Nyun Jong,Choi, Deung Jang,Lee, Kyung-Jin,Jang, Jung-tak,Choi, Jin-sil,Moon, Seung Ho,Cheon, Jinwoo American Chemical Society 2009 NANO LETTERS Vol.9 No.6
<P>Recently a memristor ( Chua, L. O. IEEE Trans. Circuit Theory 1971 , 18 , 507 ), the fourth fundamental passive circuit element, has been demonstrated as thin film device operations ( Strukov, D. B.; Snider, G. S.; Stewart, D. R.; Williams, R. S. Nature (London) 2008 , 453 , 80 ; Yang, J. J.; Pickett. M. D.; Li, X.; Ohlberg, D. A. A.; Stewart, D. R.; Williams, R. S. Nat. Nanotechnol. 2008 , 3 , 429 ). A new addition to the memristor family can be nanoparticle assemblies consisting of an infinite number of monodispersed, crystalline magnetite (Fe(3)O(4)) particles. Assembly of nanoparticles that have sizes below 10 nm, exhibits at room temperature a voltage-current hysteresis with an abrupt and large bipolar resistance switching (R(OFF)/R(ON) approximately 20). Interestingly, observed behavior could be interpreted by adopting an extended memristor model that combines both a time-dependent resistance and a time-dependent capacitance. We also observed that such behavior is not restricted to magnetites; it is a general property of nanoparticle assemblies as it was consistently observed in different types of spinel structured nanoparticles with different sizes and compositions. Further investigation into this new nanoassembly system will be of importance to the realization of the next generation nanodevices with potential advantages of simpler and inexpensive device fabrications.</P>
Jang, Youn Jeong,Lee, Jaehyuk,Lee, Jinwoo,Lee, Jae Sung American Chemical Society 2016 ACS APPLIED MATERIALS & INTERFACES Vol.8 No.12
<P>A zinc telluride (ZnTe) film modified with MoS2 and carbon has been studied as a new photocathode for solar hydrogen production from photoelectrochemical (PEC) water splitting. The modification enhances PEC activity and stability of the photocathode. Thus, the MoS2/C/ZnTe/ZnO electrode exhibits highly improved activity of -1.48 mA cm(-2) at 0 V-RHE with a positively shifted onset potential up to 0.3 V-RHE relative to bare ZnO/ZnTe electrode (-0.19 mA cm(-2), 0.18 V-RHE) under the simulated 1 sun illumination. This represents the highest value ever reported for ZnTe-based electrodes in PEC water splitting. The carbon densely covers the surface of ZnTe to protect it against photocorrosion in aqueous electrolyte and improves charge separation. In addition, MoS2 further enhances the PEC performance as a hydrogen evolution co-catalyst.</P>