http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Kim, Sohyeon,Abbas, Yawar,Jeon, Yu-Rim,Sokolov, Andrey Sergeevich,Ku, Boncheol,Choi, Changhwan IOP 2018 Nanotechnology Vol.29 No.41
<P>We performed various pulse measurements on an atomic layer deposited (ALD) HfO<SUB>2</SUB>-based resistive switching random access memory (RRAM) device and investigated its electronic synaptic characteristics. Unlike requirements for RRAM device application, to achieve the multi-state conductance changes required for the synaptic device, we employed additional sputtered TaO<SUB>x</SUB> thin film formation on the ALD HfO<SUB>2</SUB> switching medium, which leads to engineering the concentration of oxygen vacancies and modulating the conductive filaments. With this TaO<SUB>x</SUB>/HfO<SUB>2</SUB> bi-layered device, we attained gradual resistive switching, linear and symmetric conductance change, improved endurance and reproducibility characteristics compared to a single HfO<SUB>2</SUB> device. Finally, we emulated spike-timing-dependent plasticity based learning rule with pulses inspired by neural action potential, indicating its potential as an electronic synaptic device in a hardware neuromorphic system.</P>
박소현(SoHyeon Park),김은성(EunSung Kim),이학성(HakSung Lee),고관호(Kwanho Ko),유효선(HyoSun Yu),양성모(Sungmo Yang) 한국자동차공학회 2012 한국자동차공학회 부문종합 학술대회 Vol.2012 No.5
Recently, the global automobile industry develops the eco-friendly car to reduce the environmental pollution, To get better mileage of cars, the core technology is to reduce vehicle weight. Aluminium alloy is applied to light weight material at the car. The Radius Rod used in this paper is all-in-one from the method of die-casting. It is possible to mass production of goods. In this paper, the Radius Rod is focusing to obtain the effect of the lightweight. We were obtained about 7kg weight reduction by Aluminium alloy of Radius Rod compared to the steel model. Also, the radius rod analysed to satisfy safety regulations through the FEM analysis.
박소현(Sohyeon Park),양성모(Sungmo Yang),유효선(Hyosun Yu),김은성(Eunsung Kim),오상엽(Sangyeob Oh),김용관(YongKwan Kim) 한국자동차공학회 2012 한국자동차공학회 학술대회 및 전시회 Vol.2012 No.11
Recently, the automobile industry handles environmental standards and demands decrease of vehicle weight to reduce the environmental pollution. Reducing weight improves a car"s fuel economy. The weight of Aluminium Alloy used in this paper lights about 50~60% than the steel. And It have characterized that excel the stiffness, thermal resistance and corrosion resistance. The response surface method used in the paper is the statistical method. The RADIUS ROD used the lightweight material performs optimization method. Structural analysis usig the ANSYS program is executed to find static and dynamic responses. From this study, it is verified that the response surface method has advantage in optimum value and computation time in comparison to other optimization methods. By response surface method to derive the optimal design values, the analysis was performed again. The results of optimal design analysis, the weight reduces and intensity, frequency and deformation similar to existing products were able to see the analysis results.
Zinc Cobalt Layered Double Hydroxide Electrode for High-Performance Supercapacitor
사친아파라오파와,Sohyeon Yu,Hyungwoo Seo,Euijin Ju,Jeewan Yeu,Jaemin Kim,디파리파틸,신재철 한국진공학회 2019 Applied Science and Convergence Technology Vol.28 No.5
We aim to fabricate a ZnCo layered double hydroxide (LDH) nanostructure through facile one-pot hydrothermal synthesis. ZnCo LDH with interconnected hexagonal sheets having ultrathin thickness with voids are synthesized for the effective penetration of electrolytes to achieve superior electrochemical properties. The as-synthesized ZnCo LDH nanostructure is then subjected to structural, morphological, phase, and electrochemical studies. As an electrode for a supercapacitor, the ZnCo LDH has an areal capacitance of 1964 mFcm-2 at a 5 mVs-1 scan rate, an energy density of 0.22 mWhcm-2, and an excellent cycling stability (112 %) after 2000 charge–discharge cycles.
Lee, Kisu,Yu, Haejun,Lee, Jong Woo,Oh, Jungkyun,Bae, Sohyeon,Kim, Seong Keun,Jang, Jyongsik The Royal Society of Chemistry 2018 Journal of Materials Chemistry C Vol.6 No.23
<P>Inverted-structure perovskite solar cells (PSCs), with low-temperature processed poly(3,4-ethylenedioxythiophene):poly(styrene-sulfonate) (PEDOT:PSS) and perovskite-passivating phenyl-C61-butyric acid methyl ester (PCBM) employed as charge transport layers, have great potential as efficient, flexible, and hysteresis-free solar cells. However, PEDOT:PSS processed from an aqueous solution has a hygroscopic nature, and can degrade the ambient stability of moisture-vulnerable perovskite electronics. Furthermore, excess insulating PSS in the PEDOT:PSS complex can deteriorate the hole extraction and photovoltaic performance of the solar cell. In this work, polyaniline doped with camphorsulfonic acid (PANI-CSA) is introduced as a hole transport layer (HTL) to promote hole extraction ability and improve the efficiency and stability of inverted PSCs. The device fabricated with PANI-CSA exhibited superior photovoltaic performance, with a maximum efficiency of 15.42%, compared to 14.11% efficiency for the device fabricated with PEDOT:PSS. Most notably, the stability of the device fabricated with PANI-CSA was greatly improved due to a stable HTL/perovskite interface against exposure to ambient moisture.</P>
Highly Crystalline Perovskite-Based Photovoltaics via Two-Dimensional Liquid Cage Annealing Strategy
Lee, Jong Woo,Yu, Haejun,Lee, Kisu,Bae, Sohyeon,Kim, Jungwon,Han, Gi Rim,Hwang, Doyk,Kim, Seong Keun,Jang, Jyongsik American Chemical Society 2019 JOURNAL OF THE AMERICAN CHEMICAL SOCIETY - Vol.141 No.14
<P>Rendering a high crystalline perovskite film is integral to achieve superior performance of perovskite solar cells (PSCs). Here, we established a two-dimensional liquid cage annealing system, a unique methodology for remarkable enhancement in perovskite crystallinity. During thermal annealing for crystallization, wet-perovskite films were suffocated by perfluorodecalin with distinctively low polarity, nontoxic, and chemically inert characteristics. This annealing strategy facilitated enlargement of perovskite grain and diminution in the number of trap states. The simulation results, annealing time, and temperature experiments supported that the prolonged diffusion length of precursor ions attributed to the increase of perovskite grains. Consequently, without any complicated handling, the performance of perovskite photovoltaics was remarkably improved, and the monolithic grains which directly connected the lower and upper electrode attenuated hysteresis.</P> [FIG OMISSION]</BR>
Sokolov, Andrey Sergeevich,Jeon, Yu-Rim,Kim, Sohyeon,Ku, Boncheol,Lim, Donghwan,Han, Hoonhee,Chae, Myeong Gyoon,Lee, Jaeho,Ha, Beom Gil,Choi, Changhwan Elsevier 2018 APPLIED SURFACE SCIENCE - Vol.434 No.-
<P><B>Abstract</B></P> <P>We report a modulation of oxygen vacancies profile in atomic layer deposition (ALD) HfO<SUB>2-x</SUB> thin films by reducing oxidant pulse time (0.7 s–0.1 s) and study its effect on resistive switching behavior with a Ti/HfO<SUB>2-x</SUB>/Pt structure. Hf 4f spectra of x-ray photoelectron microscopy (XPS) and depth profile confirm varied oxygen vacancies profiles by shifts of binding energies of Hf 4f5/2 and Hf 4f7/2 main peaks and its according HfO<SUB>2-x</SUB> sub-oxides for each device. The ultraviolet photoelectron spectroscopy (UPS) confirms different electron affinity (χ) of HfO<SUB>2</SUB> and HfO<SUB>2-x</SUB> thin films, implying that barrier height at Ti/oxide interface is reduced. Current transport mechanism is dictated by Ohmic conduction in fully oxidized HfO<SUB>2</SUB> thin films - Device A (0.7 s) and by Trap Filled Space Charge Limited Conduction (TF-SCLC) in less oxidized HfO<SUB>2-x</SUB> thin films - Device B (0.3 s) and Device C (0.1 s). A switching mechanism related to the oxygen vacancies modulation in Ti/HfO<SUB>2-x</SUB>/Pt based resistive random access memory (RRAM) devices is used to explain carefully notified current transport mechanism variations from device-to-device. A proper endurance and long-time retention characteristics of the devices are also obtained.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Oxygen vacancies in ALD HfO<SUB>x</SUB> thin film were modulated by varying oxidant pulse time. </LI> <LI> Resistive switching behaviors are governed by connection/disruption of filament via reduction/oxidation. </LI> <LI> Conduction mechanism clearly depends on amount of oxygen vacancies. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
Abbas, Yawar,Sokolov, Andrey Sergeevich,Jeon, Yu-Rim,Kim, Sohyeon,Ku, Boncheol,Choi, Changhwan Elsevier 2018 JOURNAL OF ALLOYS AND COMPOUNDS Vol.759 No.-
<P><B>Abstract</B></P> <P>We have demonstrated the co-existence of reliable analog and digital switching characteristics with tantalum oxide based memristor by appropriate rapid thermal annealing (RTA). The device without RTA exhibits a digital SET and multilevel RESET for positive and negative sweeps, respectively. On the other hands, the device shows only analog switching characteristics such that current level increases and decreases gradually for successive positive and negative voltage sweeps, respectively, before any electroforming process with the RTA in the nitrogen ambient at the crystalline temperature of tantalum oxide which is 700 °C for 60 s. Once electroforming process is done, the device exhibits a reliable digital switching with SET at positive sweep and RESET at negative sweep voltages. In the analog state of the device we successfully emulate the synaptic characteristic of the device like spike-rate dependent plasticity (SRDP), pulse-paired facilitation (PPF) and post-tetanic potentiation (PTP). Finally, the Hermann Ebbinghaus forgetting curve is obtained from these devices. The conversion of the device from the digital SET and multilevel RESET to analogue switching is attributed to structural transition of amorphous tantalum oxide to polycrystalline tantalum oxide, different defect density and interface variation in the device.</P> <P><B>Highlights</B></P> <P> <UL> <LI> N<SUB>2</SUB> at 700 °C rapid thermal annealing (RTA) was carried out on the sputtered Ta<SUB>2</SUB>O<SUB>5</SUB>. </LI> <LI> RTA makes structural change from amorphous to polycrystalline state leading to pseudo-switching characteristics. </LI> <LI> Gradual change of current and conductance with RTA processed Ta<SUB>2</SUB>O<SUB>5-x</SUB> thin film is favorable for synaptic behaviors. </LI> </UL> </P>