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Silicon nanowire CMOS NOR logic gates featuring onevolt operation on bendable substrates

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Nano Research 2018年第5期11卷 2625-2631页

作者： Jeongje Moon Yoonjoong Kim Doohyeok lim Sangsig Kim Department of Electrical Engineering Korea University 145 Anam-ro Seongbuk-gu Seoul 02841 Republic of Korea LED PKG Development Group Samsung Electronics Co. Ltd. 1 Samsung-ro Yongin-si Gyeonggi-do 17113 Republic of Korea

In this study, we propose complementary metal-oxide-semiconductor （CMOS） NOR logic gates consisting of silicon nanowire （NW） arrays on bendable substrates. A circuit consisting of two p-channel NW field-effect transistors （NWFETs） in series and two n-channel NWFETs in parallel is constructed to operate a two- input CMOS NOR logic gate. The NOR logic gates operate at a low supply voltage of 1 V with a rail-to-rail logic swing and a high voltage gain of approximately -3.0. The exact NOR logic functionality is achieved owing to the superior electrical characteristics of the well-aligned p- and n-NWFETs, which are obtained using conventional Si-based CMOS technology. Moreover, the NOR logic gates exhibit stable characteristics and have good mechanical properties. The proposed bendable NW CMOS NOR logic gates are promising building blocks for future bendable integrated electronics.

关键词： field-effect transistor silicon nanowire NOR logic gate bendable substrate

Effect of fluidizing velocity on gas bypass and solid fraction in a dual fluidized bed gasifier and a cold model

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Particuology 2015年第1期13卷 58-65页

作者： Mook Tzeng lim Woei-Lean Saw Shusheng Pang Department of Chemical and Process Engineering University of Canterbury Centre for Energy Technology School of Chemical EngineeringUniversity of Adelaide

Dual fluidized bed gasifiers （DFBG） are effective in producing nitrogen-free syngas from biomass. How- ever, to improve the gasifier performance, pressure drops and solid fractions within the DFBG system need to be controlled. In this study, the effects of varying the fluidizing velocity in the fast fluidized bed （FFB） on the pressure drops and the solid fractions in the system were investigated in a 100 kW DFBG and in a dual fluidized bed cold model （DFCM）. Based on the experimental results, empirical correlations were developed to predict the height-averaged solid fraction in the bottom section of the FFB. Accuracy and advantages of the correlations were analyzed. The correlation is useful for design and modeling of the DFBG systems where the height-averaged solid fraction is required to be determined.

关键词： Cold model Hydrodynamics Steam gasification Dual fluidized bed

Numerical analysis of the s1020 airfoils in tandem under different flapping configurations

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Acta Mechanica Sinica 2010年第2期26卷 191-207页

作者： K.B.lim W.B.Tay Department of Mechanical Engineering National University of Singapore21 Lower Kent Ridge RoadSingapore 119077Singapore

The objective of this project is to improve the performance of the efficiency, thrust and lift of flapping wings in tandem arrangement. This research investigates the effect of the arrangement of the airfoils in tandem on the performance of the airfoils by varying the phase difference and distance between the airfoils. Three flapping configurations from an earlier phase of a research which gives high efficiency, thrust and lift are used in the tandem simulation. It is found all the different flapping configurations show improvement in the efficiency, thrust or lift when the distance between the two airfoils and the phase angle between the heaving positions of the two airfoils are optimal. The average thrust coefficient of the tandem arrangement managed to attain more than twice that of the single one （4.84 vs. 2.05）. On the other hand, the average lift coefficient of the tandem arrangement also increased to 4.59, as compared to the original single airfoil value of 3.04. All these results obtained will aid in the design of a better ornithopter with tandem wing arrangement.

关键词： Tandem Flapping· Airfoils Ornithopter·Immersed boundary

Thermo-physical Characteristics of Nickel-coated Aluminum Powder as a Function of Particle Size and Oxidant

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Chinese Journal of Mechanical Engineering 2016年第6期29卷 1244-1255页

作者： LEE Sanghyup NOH Kwanyoung lim Jihwan YOON Woongsup Advanced Energy and Propulsion Laboratory Department of Mechanical Engineering Yonsei University Missile System Integration / propulsion Center Hanwha Corp.

Aluminum particles 15-25 μm in size are widely used in fuel propellants and underwater propulsion systems in national defense research. However, these particles are covered with an aluminum oxide film, which has a high melting point, so ignition is difficult. To improve the ignitability of high-energy aluminum powder and to understand the reaction phenomenon as a function of particle size（15-25 μm, 74-105 μm, and 2.38 mm） and oxidizer（air, CO2, and argon）, the natural oxide films are chemically removed. The particles are then coated with nickel using an electro-less method. The degree of nickel deposition is confirmed qualitatively and quantitatively through surface analysis using scanning electron microscopy/energy dispersive spectroscopy. To characterize the nickel coatings, elemental analysis is also conducted by using X-ray diffraction. Thermogravimetric analysis/differential scanning calorimetry （TGA/DSC） enable comparisons between the uncoated and coated aluminum, and the reaction process are investigated through fine structural analysis of the particle surfaces and cross sections. There are little difference in reactivity as a function of oxidant type. However, a strong exothermic reaction in the smaller nickel-coated aluminum particles near the melting point of aluminum accelerates the reaction of the smaller particles. Explanation of the reactivity of the nickel-coated aluminum depending on the particle sizes is attempted.

关键词： nickel-coated aluminum TGA/DSC aluminum ignition combustion intermetallic reaction

Nasal cavity fungus ball discovered accidentally:A case report

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World Journal of Clinical Cases 2025年第5期13卷 44-48页

作者： Dae-Neung Lee Dong Hoon Lee Sang Chul lim Department of Otolaryngology-Head and Neck Surgery Chonnam National University Medical SchoolChonnam National University Hwasun HospitalHwasun 58128South Korea Department of Otolaryngology-Head and Neck Surgery Chonnam National University Medical SchoolHwasun HospitalChonnam National University Hwasun HospitalHwasun 58128South Korea Department of Otolaryngology-Head and Neck Surgery Chonnam National University Medical SchoolKwangju 501190South Korea

BACKGROUND Fungal balls within the nasal cavity are an exceedingly rare clinical entity,typically presenting with nonspecific symptoms or being identified *** SUMMARY This report presents an incidental discovery of a fungal ball in the nasal cavity during routine imaging,with no associated clinical *** This case underscores the importance of considering the possibility of asympto-matic presentations of nasal fungal balls,which may be detected incidentally during imaging evaluations.

关键词： Fungi Mycoses Fungus ball Nasal cavity Nasal surgical procedures Case report

Detection of chemicals in water using a three-dimensional graphene porous structure as liquid-vapor separation filter

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Nano Research 2017年第3期10卷 971-979页

作者： Taekyung lim Jaejun Lee Jonghun Lee Sanghyun Ju Department of Physics Kyonggi University Suwon Gyeonggi-Do 443-760 Republic of Korea

In this study, we report the utilization of a three-dimensional （3D） porous graphene structure as liquid-vapor separation filter, which allows the passage of chemical vapors while blocking liquid chemicals and water. The blockage of liquid chemicals and water from semiconducting sensing regions is required to avoid abnormal transistor characteristics. In order to impart omniphobic characteristics, a （heptadecafluoro-1,1,2,2-tetrahydrodecyl）trichlorosilane （HDF-S） self-assembled monolayer was coated on the surface of the 3D porous graphene structure. The concentration of chemical agents in water could be consistently detected by observing the shift in the threshold voltage in the oxide nanowire transistor covered by the HDF-S self-assembled 3D graphene structure. The proposed monitoring method is expected to offer means for application in different environments by providing a stable sensing performance.

关键词： chemical detection graphene structure nanowire transistor self-assembled monolayer omniphobicity

Model development to estimate site index values for six major tree species in North Korea

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Journal of Forestry Research 2023年第2期34卷 387-400页

作者： Sohee Park A-Ram Yang Eun-hee Kim Joongbin lim Division of Global Forestry Department of Future Forest StrategyNational Institute of Forest ScienceSeoul 02455Republic of Korea Forest ICT Research Center National Institute of Forest ScienceSeoul 02455Republic of Korea

Due to considerable deforestation in North Korea,there is a need to plan forest restoration programs based on scientific forest *** this study,a methodology was developed for estimating the site index values of six major tree species and the forest productivity *** site index values of these tree species were derived in South Korea using the Chapman-Richards *** values were used with data from the 6th National Forest Inventory,which included 20 types of edaphic,topographic,and climatic factors,and random forest analysis—a widely used machine learning technique for spatial prediction—to develop a new model for estimating the site index values of these species across South *** prediction accuracy of this model was evaluated using the root mean square *** results show that the prediction accuracy was high,with a root mean square error of~***,the importance of the variables related to climate and geography was generally *** proposed site index estimation model for six tree species was applied across North Korea,and its effectiveness tested by comparing the estimated values with those reported in literature from North *** differences between the model outputs and recorded data in the northern alpine regions were presumably due to the lack of data for high-altitude regions in South *** model is based on the determination of the suitability of tree species in restoration ***,it can contribute to the evaluation of forest productivity in North Korea and may help plan efficient forest restoration programs.

关键词： Environmental factors Forest productivity Machine learning North Korea Random forest Site index

Direct high-resolution X-ray imaging exploiting pseudorandomness

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Light(Science & Applications) 2023年第5期12卷 776-788页

作者： KyeoReh Lee Jun lim Su Yong Lee YongKeun Park Department of Physics Korea Advanced Institute of Science and TechnologyDaejeon 34141Republic of Korea KAIST Institute for Health Science and Technology Korea Advanced Institute of Science and TechnologyDaejeon 34141Republic of Korea Pohang Accelerator Laboratory Pohang University of Science and TechnologyPohangKyungbuk 37637Republic of Korea Tomocube Inc Daejeon 34051Republic of Korea

Owing to its unique penetrating power and high-resolution capability,X-ray imaging has been an irreplaceable tool since its *** the significance,the resolution of X-ray imaging has largely been limited by the technical difficulties on X-ray lens *** lensless imaging methods have been proposed,but are yet relying on multiple measurements or additional constraints on measurements or *** we present coherent specklecorrelation imaging(CSI)using a designed X-ray *** has no prerequisites for samples or ***,from a single shot measurement,the complex sample field is retrieved based on the pseudorandomness of the speckle intensity pattern,ensured through a *** achieve a spatial resolution of 13.9 nm at 5.46 keV,beating the feature size of the diffuser used(300 nm).The high-resolution imaging capability is theoretically explained based on fundamental and practical *** expect the CSI to be a versatile tool for navigating the unexplored world of nanometer.

关键词： resolution speckle replace

A Novel Application of Multi-Resonant Dissipative Elastic Metahousing for Bearings

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Acta Mechanica Solida Sinica 2021年第4期34卷 449-465页

作者： Muhammad C.W.lim N.S.Vyas Department of Architecture and Civil Engineering City University of Hong KongKowloonHong Kong SARChina Department of Mechanical Engineering Indian Institute of Technology KanpurKanpur208016India

Bearing as an important machine element is widely used for industrial and automotive *** certain operational speed,bearings induce disturbing vibrations and noises that affect machine service life,productivity and passenger comfort in case of vehicle *** elastic metamaterials have caught considerable attention of scientific community due to their effective medium properties and peculiar dynamic characteristics including frequency bandgaps that can be effectively applied to attenuate and control undesirable vibration and *** a substantial amount of theoretical work for effective medium characteristics and dynamic properties of acoustic/elastic metamaterials has been reported,the practical design and application of these composite structures for real-life engineering problems still remain *** present study intends to investigate a potential application of dissipative elastic metamaterials in controlling the bearing-generated vibration and noises over an ultrawide frequency *** study is based on a simple analytical model together with rigorous finite element numerical *** has been established that the dissipative characteristic of resonant system caused by larger material mismatch broadens the local resonance bandgaps beyond the bounding resonance frequency at the cost of wave *** order to achieve broadband vibration and noise control,multi-resonant composite structures are embedded inside the bearing housing in five different *** reported results revealed the presence of broadband wave attenuation zone distributed from 3 to 52 kHz with consideration of material *** bearing-generated vibration and noises lying inside the wave attenuation zone will be *** feasibility study provides a new concept for the design and application of acoustic/elastic metamaterials in the bearing industry to improve machine service life and to enhance productivity and passenger comfo

关键词： Bearing metahousing Dissipative elastic metamaterials Frequency Local resonance bandgap Vibration attenuation zone