http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
[연료 및 윤활유부문] 맥퍼슨 스트러트의 부품유격에 따른 소음영향에 관한 연구
윤기현(Kihyun Yoon),이재용(Jaeyong Lee) 한국자동차공학회 2000 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
A recent trend within the automotive industry has been an emphasis on the reduction of noise future vehicle applications. This trend created a need for the development of methods to predict the noise within the vehicle environment. In particular, the development of models for the reduction of noise must be based the result that account for the dynamic property between components. The noise vehicle in driving is mostly transferred through the suspension system or created from the damper. So, the information of parameter for the damper noise is very important to characterize the vehicle noise. After the loading conditions is performed with real vehicle installing condition, this paper describes a finite element model of a damper model with the clearance between and rod guide and rattle the suspension system. The results of a study of the damper noise subjected to dynamic loading condition and rattle the suspension system. The results of a study of the damper noise subjected to dynamic loading condition are presented. Additionally, the effects of the clearance in the damper are considered and the results are displayed.
Kihyun Kwon,Sungkyu Lim,Sungjoon Cho,Jeonghoon Yoon,Jeiwon Cho,Changyul Cheon,Youngwoo Kwon IEEE 2006 IEEE microwave and wireless components letters Vol.16 No.1
<P>A three-way planar-type probe optimized for in-vivo permittivity measurements of biological materials has been developed. The probe in this letter consists of three orthogonally-faced probing apertures, which allows one to make accurate and uninterrupted measurements in three different directions per each insertion. As a result, this probe is significantly less invasive for the collection of the desired information of the biological materials, thus providing a vastly improved solution for in-vivo measurements. This probe can also be used for microwave ablation, in which case the treating region can be significantly expanded</P>
Mobile Unified Memory-Storage Structure Based on Hybrid Non-Volatile Memories
Yoon, Su-Kyung,Youn, Young-Sun,Park, Kihyun,Kim, Shin-Dug Association for Computing Machinery 2017 ACM journal on emerging technologies in computing Vol.13 No.3
<P>In mobile computing systems, the limited amount of main memory space leads to page swap operation overhead and data duplication in both main memory and secondary storage. Furthermore, SQLite write operations in mobile devices such as smartphones and tablet PCs tend to frequently overwrite data to storage, significantly degrading performance. Thus, this article presents a unified memory-storage structure that is optimized for mobile devices and blurs the boundary between the existing main memory layer and secondary storage layer. This structure can eliminate the conventional page-swap operations that cause significant performance degradation and support fast program execution time. The unified memory-storage structure consists of a dynamic RAM (DRAM) and phase change memory (PCM)-based dual buffering module, a hybrid unified memory-storage array consisting of DRAM and NAND Flash memory, and an associated unified storage translation layer devised for the memory address and file translation mechanism as a system software module. This hybrid array of non-volatile memories is formed as a single memory-disk integrated storage space that can be logically divided into static and dynamic spaces. Experimental results show that the overall performance of the hybrid unified memory-storage system with the buffering structure increases by around 13% and power consumption is also improved by 35%, compared to current mobile system.</P>
Bandgap Engineering and Strain Effects of Core–Shell Tunneling Field-Effect Transistors
Yoon, Jun-Sik,Kim, Kihyun,Meyyappan, M.,Baek, Chang-Ki IEEE 2018 IEEE transactions on electron devices Vol.65 No.1
<P>DC characteristics of n-type SiGe heterojunction nanowire tunneling field-effect transistors (TFETs) adopting a core–shell structure are investigated using 3-D numerical simulation. Different mole fractions between the core and the shell regions induce strain effects along the nanowire, which modulate the energy bandgap and thus the dc performance of the devices. The SiGe core–shell TFETs with greater mole fractions in the core regions increase the drive currents greatly by both Ge content and strain effects which decrease the tunneling length and increase the band-to-band (BTB) generation rate according to Kane’s nonlocal tunneling model. In addition, tensile (compressive) strains for the shell (core) regions as well as shear strains reduce the energy bandgap according to the deformation potential theory, decreasing the subthreshold swing as well as increasing the BTB generation rate. Compared to all other Si/Ge heterojunction TFETs, the proposed SiGe core–shell TFETs are superior with high drive currents and on/off-current ratios.</P>
Yoon, Ki Ro,Shin, Kihyun,Park, Jiwon,Cho, Su-Ho,Kim, Chanhoon,Jung, Ji-Won,Cheong, Jun Young,Byon, Hye Ryung,Lee, Hyuk Mo,Kim, Il-Doo American Chemical Society 2018 ACS NANO Vol.12 No.1
<P>To achieve a high reversibility and long cycle life for lithium–oxygen (Li–O<SUB>2</SUB>) batteries, the irreversible formation of Li<SUB>2</SUB>O<SUB>2</SUB>, inevitable side reactions, and poor charge transport at the cathode interfaces should be overcome. Here, we report a rational design of air cathode using a cobalt nitride (Co<SUB>4</SUB>N) functionalized carbon nanofiber (CNF) membrane as current collector-catalyst integrated air cathode. Brush-like Co<SUB>4</SUB>N nanorods are uniformly anchored on conductive electrospun CNF papers via hydrothermal growth of Co(OH)F nanorods followed by nitridation step. Co<SUB>4</SUB>N-decorated CNF (Co<SUB>4</SUB>N/CNF) cathode exhibited excellent electrochemical performance with outstanding stability for over 177 cycles in Li–O<SUB>2</SUB> cells. During cycling, metallic Co<SUB>4</SUB>N nanorods provide sufficient accessible reaction sites as well as facile electron transport pathway throughout the continuously networked CNF. Furthermore, thin oxide layer (<10 nm) formed on the surface of Co<SUB>4</SUB>N nanorods promote reversible formation/decomposition of film-type Li<SUB>2</SUB>O<SUB>2</SUB>, leading to significant reduction in overpotential gap (∼1.23 V at 700 mAh g<SUP>–1</SUP>). Moreover, pouch-type Li-air cells using Co<SUB>4</SUB>N/CNF cathode stably operated in real air atmosphere even under 180° bending. The results demonstrate that the favorable formation/decomposition of reaction products and mediation of side reactions are hugely governed by the suitable surface chemistry and tailored structure of cathode materials, which are essential for real Li–air battery applications.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/ancac3/2018/ancac3.2018.12.issue-1/acsnano.7b03794/production/images/medium/nn-2017-03794x_0007.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/nn7b03794'>ACS Electronic Supporting Info</A></P>
Optical Characteristics of Silicon-Based Asymmetric Vertical Nanowire Photodetectors
Yoon, Jun-Sik,Kim, Kihyun,Meyyappan, M.,Baek, Chang-Ki Institute of Electrical and Electronics Engineers 2017 IEEE transactions on electron devices Vol.64 No.5
<P>Wavelength-selective absorption phenomena of silicon-based vertical nanowire (NW) photodetectors (PDs) are investigated using 3-D numerical simulations. The difference in the refractive indexes between silicon NW and its surrounding material induces diameter-dependent waveguide effects at several specific wavelengths for asymmetric as well as symmetric structures. But the asymmetric NW PDs with a large difference in diameter between the top side and the bottom side have loss of waveguide effects. All the NW PDs achieve high external quantum efficiency (EQE) peaks with an increase in NW height. Decreasing the NW pitch or increasing the NW density also increases the EQE peak values for awide range of wavelengths, but too densely packed NWs induce high coupling between the nearest NWs, thus losing wavelength-selective properties. Vertical NW PDs having slightly bottom-wide asymmetric structure decrease reflectance and transmittance of the incident light because of the narrow top-side and wide bottom-side silicon NW cross sections, respectively, thus achieving higher EQEs. Bottom-wide asymmetric NW PDs are promising to enhance the optical characteristics as well as to maintain waveguide properties for optical sensor applications.</P>
Performance and Variations Induced by Single Interface Trap of Nanowire FETs at 7-nm Node
Yoon, Jun-Sik,Kim, Kihyun,Rim, Taiuk,Baek, Chang-Ki Institute of Electrical and Electronics Engineers 2017 IEEE transactions on electron devices Vol.64 No.2
<P>DC/AC performance and the variations due to single interface trap of the nanowire (NW) FETs were investigated in the 7-nm technology node using fully calibrated TCAD simulation. Shorter junction gradient and greater diameter reducedRC delay without short channel degradations. Spacer with smaller dielectric constants decreased parasitic and gate capacitances with a slight decrease of ON-state currents, thus minimizing RC delay. Interface traps for the variability analysis were P-b0, P-b1, and fixed oxide charges at the Si/SiO2 interface. P-b0 negligibly affected dc variationsbutP(b1) at the drain underlap regions increased gate-induced drain leakage currents, which induced greater OFF-state current variations. Fixed oxide charges, especially at the middle of the channel regions, shifted drain currents toward left by bending the energy band downward locally near the single interface trap. To maximize the performance as well as to minimize the variations induced by the interface traps, careful surface treatment for the drain underlap regions and adaptation of vertical NW structure are needed while maintaining fine short channel characteristics.</P>
ZnO nanowire-based nonvolatile memory devices with Al2O3 layers as storage nodes.
Keem, Kihyun,Kang, Jeongmin,Yoon, Changjoon,Yeom, Donghyuk,Jeong, Dong-Young,Park, Byoungjun,Park, Jucheol,Kim, Sangsig American Scientific Publishers 2009 Journal of Nanoscience and Nanotechnology Vol.9 No.7
<P>Top-gate ZnO nanowire field-effect transistors (FETs) with Al2O3 gate dielectric layers as storage nodes were fabricated and their memory effects were characterized in this work. The Al2O3 layers deposited on the ZnO nanowire channels were utilized not only as gate dielectric ones but also as charge trapping ones. For a representative top-gate ZnO nanowire FET, its I(DS)-V(GS) characteristics for the double sweep of the gate voltages exhibit the counterclockwise hysteresis and the threshold voltage shift. The gate voltage in the pulse form was applied for 1 s, and the threshold voltage shift of I(DS)-V(GS) characteristics was extended from 0.3 to 0.8 V compared with that for the double sweep. In this ZnO nanowire FET, negative charge carriers originated from the gate electrode are stored in the Al2O3 layer for applied negative gate voltages, and they are extracted for applied positive gate voltages.</P>