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991.
Euh Duck Jeong Hyun Ju Han Ok Sang Jung Myoung Gyu Ha Chil Hoon Doh Min Ji Hwang Ho-Soon Yang K.S. Hong 《Materials Research Bulletin》2012,47(10):2847-2850
Pure and metal (Cu, Al, Sn, and V)-doped Li4Ti5O12 powders are prepared with solid-state reaction method. The effects of dopants on the physical and electrochemical properties are characterized by using TGA, XRD, and SEM. Compared with pure Li4Ti5O12, metal-doped Li4Ti5O12 powders show structural stability and enhanced lithium ion diffusivity brought by doped metal ions. Voltage characteristics and initial charge–discharge characteristics according to the C rates in pure and metal-doped Li4Ti5O12 electrode materials are studied. Pure Li4Ti5O12 powder shows a relatively good discharge capacity of 164 mAh/g at a rate 0.2C, and some of metal-doped Li4Ti5O12 powders show higher discharge capacities. Metal-doped Li4Ti5O12 powders are promising candidates as anode materials for lithium-ion batteries. 相似文献
992.
Hwang D Lee H Jang SY Jo SM Kim D Seo Y Kim DY 《ACS applied materials & interfaces》2011,3(7):2719-2725
We report a simple method to prepare hierarchically structured TiO(2) spheres (HS-TiO(2)), using an electrostatic spray technique, that are utilized for photoelectrodes of highly efficient dye-sensitized solar cells (DSSCs). This method has an advantage to remove the synthesis steps in conventional sol-gel method to form nano-sized spheres of TiO(2) nanoclusters. The fine dispersion of commercially available nanocrystalline TiO(2) particles (P25, Degussa) in EtOH without surfactants and additives is electro-sprayed directly onto a fluorine-dopoed tin-oxide (FTO) substrate for DSSC photoelectrodes. The DSSCs of HS-TiO(2) photoelectrodes show high energy conversion efficiency over 10% under illumination of light at 100 mW cm(-2), AM1.5 global. It is concluded from frequency-dependent measurements that the faster electron diffusion coefficient and longer lifetime of HS-TiO(2) than those in nonstructured TiO(2) contribute to the enhanced efficiency in DSSCs. 相似文献
993.
Yongtaek Hwang Kyuyoung Heo Chang Hwan Chang Man Kil Joo Moonhor Ree 《Thin solid films》2006,510(1-2):159-163
High dielectric constant (high-k) gate dielectric alumina films were prepared with nanoscale thicknesses on p-type silicon substrates by atomic layer deposition (ALD) with alternating pulses of trimethyl aluminum, nitrogen, ozone and nitrogen, and some of them were further thermally annealed. These high-k gate dielectric films were characterized by synchrotron X-ray reflectivity (XR), and the XR data were quantitatively analyzed, providing the following structural parameters of each gate dielectric film: the surface roughness and interfacial roughness, the electron density profile, the number of layers, and the thickness of individual layers. These structural characteristics were then analyzed in detail by considering the ALD processing conditions and post-thermal annealing history. 相似文献
994.
Sheng-Chang Chen Chyi-Ren Dow Ren-Di Wang Yi-Hsung Li Shiow-Fen Hwang 《Wireless Personal Communications》2009,48(3):441-462
Multicasting is an essential service for mobile ad-hoc networks. A major challenge for multicasting in mobile ad-hoc networks
(MANETs) is the unstable forwarding path. This work presents a reliable multicasting protocol for mobile ad-hoc networks.
A virtual backbone is used as a shared structure for multiple sessions. A lost packet recovery scheme is developed for reliable
packet transmission, called the Recovery Point (RP) scheme. The RP scheme maintains the data packets received from the source
for recovering lost packets for its downstream RPs. In addition, we combine the Forward Error Correction (FEC) technology
with our RP scheme to enhance the reliability of our RP scheme. A mergence scheme for RP is also proposed to avoid excessive
control overhead. Our RP and FEC based scheme can be used to improve the reliability and efficiency of the traditional non-acknowledged
multicasting approach. Experiments were conducted to evaluate the proposed multicasting scheme. The results demonstrate that
our scheme outperforms other schemes in terms of packet delivery ratio and multicast efficiency. Furthermore, the simulation
results also demonstrate that our approach is stable in networks with high mobility.
相似文献
Shiow-Fen HwangEmail: |
995.
Jaesik Yoon Hyejung Choi Dongsoo Lee Ju-Bong Park Joonmyoung Lee Dong-Jun Seong Yongkyu Ju Man Chang Seungjae Jung Hyunsang Hwang 《Electron Device Letters, IEEE》2009,30(5):457-459
We have investigated a Cu-doped MoOx/GdOx bilayer film for nonvolatile memory applications. By adopting an ultrathin GdOx layer, we obtained excellent device characteristics such as resistance ratio of three orders of magnitude, uniform distribution of set and reset voltages, switching endurance up to 104 cycles, and ten years of data retention at 85degC. By adopting bilayer films of Cu-doped MoOx/GdOx, a local filament was formed by a two-step process. Improved memory characteristics can be explained by the formation of nanoscale local filament in the ultrathin GdOx layer. 相似文献
996.
Shih-Arn Hwang Cheng-Wen Wu 《Very Large Scale Integration (VLSI) Systems, IEEE Transactions on》2001,9(4):489-499
Hardware implementation of data compression algorithms is receiving increasing attention due to exponentially expanding network traffic and digital data storage usage. In this paper, we propose several serial one-dimensional and parallel two-dimensional systolic-arrays for Lempel-Ziv data compression. A VLSI chip implementing our optimal linear array is fabricated and tested. The proposed array architecture is scalable. Also, multiple chips (linear arrays) can be connected in parallel to implement the parallel array structure and provide a proportional speedup 相似文献
997.
Hwang S. H. Lim J. W. Lee W.-J. Kim G. W. Cho C. H. An J. B. Jung K. Y. Cha K. S. Rho B. S. 《Photonics Technology Letters, IEEE》2010,22(3):167-169
998.
Woo‐Seok Cheong Jeong‐Min Lee Jong‐Ho Lee Sang‐Hee Ko Park Sung Min Yoon Chun‐Won Byun Shinhyuk Yang Sung Mook Chung Kyoung Ik Cho Chi‐Sun Hwang 《ETRI Journal》2009,31(6):660-666
We investigate the effects of interfacial dielectric layers (IDLs) on the electrical properties of top‐gate In‐Ga‐Zn‐oxide (IGZO) thin film transistors (TFTs) fabricated at low temperatures below 200°C, using a target composition of In:Ga:Zn = 2:1:2 (atomic ratio). Using four types of TFT structures combined with such dielectric materials as Si3N4 and Al2O3, the electrical properties are analyzed. After post‐annealing at 200°C for 1 hour in an O2 ambient, the sub‐threshold swing is improved in all TFT types, which indicates a reduction of the interfacial trap sites. During negative‐bias stress tests on TFTs with a Si3N4 IDL, the degradation sources are closely related to unstable bond states, such as Si‐based broken bonds and hydrogen‐based bonds. From constant‐current stress tests of Id = 3 µA, an IGZO‐TFT with heat‐treated Si3N4 IDL shows a good stability performance, which is attributed to the compensation effect of the original charge‐injection and electron‐trapping behavior. 相似文献
999.
Adaptive learning control of milling operations 总被引:1,自引:0,他引:1
An adaptive learning control of milling operations in order to improve productivity is presented. Basically, the proposed control system consists of two parts. A feedforward neural network is first developed to acquire the inverse-dynamics model of the controlled plant. Then, a fuzzy feedback mechanism is designed to perform an adaptive modification of connection weights for the feedforward neural network. Based on this control system, an on-line adjustment of feedrate to achieve a constant milling force under a variety of cutting conditions is shown. 相似文献
1000.
Hyeokjac Lee Jeong Mo Hwang Young June Park Hong Shick Min 《Electron Device Letters, IEEE》1999,20(5):251-253
In this paper, we report abnormal junction leakage current characteristics in sub-quarter micron CMOS formed by OSELO-II isolation method and high-energy ion implantation for well formation. The phenomena have not been found in other isolation schemes such as single Si3N4 spacer OSELO (SSS-OSELO), modified conventional LOCOS (MLOCOS) and shallow trench isolation (STI). From the defect analysis and process simulation based on the actual recipe, the abnormal leakage is found to be generated from the lattice defects at the edge of field oxide and caused by the combination of oxidation stress, and high-energy ion implantation. A process condition in the high-energy ion implantation and isolation process is proposed to reduce the leakage current 相似文献