http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Quantum Size Effects on the Chemical Sensing Performance of Two-Dimensional Semiconductors
Nah, Junghyo,Kumar, S. Bala,Fang, Hui,Chen, Yu-Ze,Plis, Elena,Chueh, Yu-Lun,Krishna, Sanjay,Guo, Jing,Javey, Ali American Chemical Society 2012 The Journal of Physical Chemistry Part C Vol.116 No.17
<P>We investigate the role of quantum confinement on the performance of gas sensors based on two-dimensional InAs membranes. Pd-decorated InAs membranes configured as H<SUB>2</SUB> sensors are shown to exhibit strong thickness dependence, with ∼100× enhancement in the sensor response as the thickness is reduced from 48 to 8 nm. Through detailed experiments and modeling, the thickness scaling trend is attributed to the quantization of electrons which favorably alters both the position and the transport properties of charge carriers; thus making them more susceptible to surface phenomena.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/jpccck/2012/jpccck.2012.116.issue-17/jp300446z/production/images/medium/jp-2012-00446z_0002.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/jp300446z'>ACS Electronic Supporting Info</A></P>
III–V Complementary Metal–Oxide–Semiconductor Electronics on Silicon Substrates
Nah, Junghyo,Fang, Hui,Wang, Chuan,Takei, Kuniharu,Lee, Min Hyung,Plis, E.,Krishna, Sanjay,Javey, Ali American Chemical Society 2012 Nano letters Vol.12 No.7
<P>One of the major challenges in further advancement of III–V electronics is to integrate high mobility complementary transistors on the same substrate. The difficulty is due to the large lattice mismatch of the optimal <I>p</I>- and <I>n</I>-type III–V semiconductors. In this work, we employ a two-step epitaxial layer transfer process for the heterogeneous assembly of ultrathin membranes of III–V compound semiconductors on Si/SiO<SUB>2</SUB> substrates. In this III–V-on-insulator (XOI) concept, ultrathin-body InAs (thickness, 13 nm) and InGaSb (thickness, 7 nm) layers are used for enhancement-mode <I>n</I>- and <I>p</I>- MOSFETs, respectively. The peak effective mobilities of the complementary devices are ∼1190 and ∼370 cm<SUP>2</SUP>/(V s) for electrons and holes, respectively, both of which are higher than the state-of-the-art Si MOSFETs. We demonstrate the first proof-of-concept III–V CMOS logic operation by fabricating NOT and NAND gates, highlighting the utility of the XOI platform.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/nalefd/2012/nalefd.2012.12.issue-7/nl301254z/production/images/medium/nl-2012-01254z_0002.gif'></P>
박판근(Pangun Park),김선(Seon Kim),나정효(Junghyo Nah) 한국정보통신학회 2023 한국정보통신학회논문지 Vol.27 No.3
최근 제안된 MIMO-AirComp (Multiple input multiple output over-the-air computation) 기술은 무선 통신과 컴퓨팅 자원을 효율적으로 통합하기 위하여 다중 액세스 채널의 중첩 속성을 활용한다. 본 논문에서는 제어 시스템의 제어 신호를 추정하기 위한 MIMO-AirComp 프레임워크를 제안한다. 제시된 MIMO-AirComp 프레임워크는 센서의 측정 정보 전처리, 무선 채널의 협업 중첩, 제어기의 수신 신호 후처리 기능으로 구성된다. 시뮬레이션을 활용한 성능평가를 통하여, 제안된 MIMO-AirComp가 기존 방식에 비하여 제어 신호 처리량을 향상 시켜 제어 시스템의 성능을 개선하는 것을 보여 주었다. 특히, 제안된 MIMO-AirComp 기법은 다수의 고잡음 무선 센서로 구성된 제어 시스템에서 기존의 분리된 무선 통신 및 컴퓨팅 설계 방식으로는 불가하였던 시스템의 안정성을 보장하였다. The recently proposed technique, multiple input multiple output over-the-air computation (MIMO-AirComp), leverages the superposition property of the multiple access channel to efficiently integrate the communication and computation. This article proposes the MIMO-AirComp framework to compute the control signal of control systems. The proposed framework efficiently computes the target control signal by coordinating local pre-processing at each node, aggregation through the wireless channel, and post-processing at the controller. The simulation results show that the proposed MIMO-AirComp framework considerably improves the control performance by increasing the computation throughput compared to the conventional separated communication and computation approach. The proposed scheme with many nodes essentially suppresses the noise impact of both the wireless channel and the measurement, while the conventional one only reduces the impact of the channel noise. Specifically, the proposed scheme guarantees control stability in a network composed of high-noise wireless sensors, which is infeasible with the conventional approach.
Lee, Song Mi,Shin, Sung-Ho,Nah, Junghyo,Lee, Min Hyung IOP 2017 Nanotechnology Vol.28 No.39
<P>Appropriate control of energy band bending at the interface between semiconductors and electrolytes are closely related to performance of photoelectrochemical (PEC) water splitting. Dipoles formed near the surface of semiconductors induces energy band bending at the interface. Energy band bending control has been demonstrated by employing charged molecules and piezoelectric materials. However, chemical and piezoelectric approaches have demerit of chemical instability and inducement of instantaneous dipole, respectively. To overcome these problems, we adopted the ferroelectric material for PEC water splitting, where spontaneous dipoles in the material can be oriented by applying external electric field. In this work, we hydrothermally synthesized vanadium (V)-doped ferroelectric ZnO nanosheets and employed to systematically investigate the dipole effect on performance of V-doped ZnO PEC for water oxidation. Consequently, positively polarized V-doped ZnO photoanode exhibits 125% enhanced water splitting efficiency compared to negatively polarized ones due to favorable band bending for carrier transport from semiconductor to water.</P>
HVAC 케이블 인증시험시 화학분석 항목 도입에 관한 고찰
김성수(Sungsoo Kim),김민주(Minju Kim),나정효(Junghyo Nah) 대한전기학회 2021 대한전기학회 학술대회 논문집 Vol.2021 No.10
본 논문은 전력케이블 인정시험 항목 중 Type Test 시 케이블 접속함 내 가스 또는 절연유의 성분을 분석하는 DGA법을 활용하여 케이블 접속함 설계의 적정성을 검증하는데 활용해보고자 한다. 또한, Type Test 화학분석 결과를 토대로 Type Test 이후에 진행되는 케이블 장기신뢰성 시험(PQ Test) 성공 가능성을 사전에 검토하는 방법에 대해 다루고자 한다.
Investigation of 3-D Printed, Electrically Small, and Thin Magnetic Dipole Antenna
Kong, Myeongjun,Lee, Su-Hyeon,Shin, Geonyeong,Nah, Junghyo,Yoon, Ick-Jae IEEE 2018 IEEE antennas and wireless propagation letters Vol.17 No.4
<P>A novel design of electrically small, extremely thin, and horizontally polarized magnetic dipole antenna is proposed. It is composed of multiple folded arms packed in an extremely thin height of 0.0016λ, with the electrical size <I>ka</I> of 0.276. The radiation efficiency is 87% from the simulation. The radiation properties are investigated, and its operation as a small magnetic dipole antenna is confirmed. A three-dimensional printing technology is used for building the prototype due to the complexity of the proposed structure. The experimental results show good agreement with the computed expectation values.</P>
Interfacial Mode Interactions of Surface Plasmon Polaritons on Gold Nanodome Films
Ko, Woo Ri,Zhang, Jinlin,Park, Hyeong-Ho,Nah, Junghyo,Suh, Jae Yong,Lee, Min Hyung American Chemical Society 2016 ACS APPLIED MATERIALS & INTERFACES Vol.8 No.32
<P>Hollow metallic nanodome structures were fabricated using anodized aluminum oxide (AAO) nanopores as deposition and sacrificial templates. Individual Au nanodomes inherit the unique shapes of the well-defined AAO membranes whose pedestal cells become square or hexagonal lattices with hemispheres in close proximity. Minimal contact between the hollow nanodomes and the glass substrate provide an identical dielectric medium across the film. The nanodome Au films support surface plasmon polaritons (SPPs) of strong air-Au and weak Au-glass modes in the light transmission dispersions. The mode crossings of distinct SPPs exhibit characteristic energy gaps, which depend on the periodic geometries of the nanostructures.</P>
Shin, Sung-Ho,Choi, Seong-Young,Lee, Min Hyung,Nah, Junghyo American Chemical Society 2017 ACS APPLIED MATERIALS & INTERFACES Vol.9 No.47
<P>We report high-performance piezoelectric nanogenerators, (PENGs) with nanoimprinted sol-gel BaTiO3 (BTO) nanopillar array polarized under high electric field,and ultraviolet. The PENGs fabricated using this method demonstrate greatly enhanced Output foliage Of similar to 10 V and current density of similar to 1.2 mu A cm(-2), respectively, in comparison to that of flat PENG, Further, the PENG demonstrates uniform output characteristics over the entire device area thanks to uniform nanoimprint pillar array. The approach introduced here is simple effective, reliable, and reproducible way to fabricate high-performance sol-gel-based PENGs and electronic devices.</P>