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71.
Jeong-Sun Oh Joon-Hyung An Sun-Ok Lee Yeon-Hum Yun Bo-An Kang Sang-Bok Kim Kyu-Seog Hwang 《Metals and Materials International》2002,8(5):459-462
We prepared zirconia thin films on (100) Si wafer by using a chemical solution deposition with a zirconium naphthenate as
a starting material. The films were pyrolyzed at 500°C for 10 min and finally annealed for 30 min in air at 500°C. Amorphous
films after annealing had no distinct structure and were uniform along the cross section line.In vitro formation of the calcium phosphate was evaluated by the field emission-scanning electron microscope, energy dispersive X-ray
spectrometer and Fourier transform infrared spectroscopy. 相似文献
72.
Jooho Hwang Chun-Hong Park Chan-Hong Lee Seung-Woo Kim 《International Journal of Machine Tools and Manufacture》2006,46(7-8):801-810
This paper describes an estimation and correction method for the two-dimensional (2D) position errors of a planar XY stage that is driven along the Y-axis by two linear motors. The 2D position errors of the stage were estimated and corrected based on measured motion errors from a conventional laser interferometer system. To compensate for the planar XY stage 2D position errors, corrections were introduced for the yaw, perpendicular, straightness and 1D position errors along each axis, which are predominantly caused by linear scale, yaw, and pitching motion errors. The effect of the motion error corrections was evaluated by diagonal measurements based on the ISO230-6 standard and six different 1D position error measurements along the X and Y-axes. By applying error motion corrections, the diagonal systematic deviation at the center point was improved from 499.7 μm to 1.16 μm, and the estimated maximum 2D position errors were improved to −0.263 and 0.530 μm in the X and Y directions, respectively. The diagonal systematic deviation at a corner point was 1.23 μm and the estimated maximum difference between the corner and center points improved from −2.603 and 2.603 μm to −0.05 and 0.12 μm in the X and Y directions respectively. 相似文献
73.
A new approach using a neural network to process the features of the cutting force signal for the recognition of tool breakage in face milling is proposed. The cutting force signal is first compressed by averaging the cutting force signal per tooth. Then, the average cutting force signal is passed through a median filter to extract the features of the cutting force signal due to tool breakage. With the back propagation training process, the neural network memorizes the feature difference of the cutting force signal between with and without tool breakage. As a result, the neural network can be used to classify the cutting force signal with or without tool breakage. Experiments show this new approach can sense tool breakage in a wide range of face milling operations. 相似文献
74.
Ahn Kyu-Hong Hwang Jong-Hyuk Song Kyung-Guen Jung Yong-Ho Cho Eul-Saeng Lim Byung-Ran Kim Kwang-Soo 《Metals and Materials International》2004,10(2):167-170
The performance of an attached growth wastewater treatment process was investigated in an effort to improve nitrogen removal
efficiency. Recycled Yakult (lactic acid fermentation drink) bottles made of polystyrene were used as a biofilm media. The
use of Yakult bottles as a biofilm media has been attempted by numerous researchers in Japan for the removal of solids and
organics. However, these studies focused only on the removal of solids and organics. This study extended their application
to the removal of nitrogen for domestic sewage treatment. Yakult media was placed in a reactor with 70% apparent reactor volume
in a conventional A/O process. The bottom of the Yakult media was removed, and randomly filled Yakult media were effectively
able to reduce the flow in tanks, resulting in an increase in the contact time between pollutants and microorganisms. With
higher HRT, the nitrogen removal efficiency was increased by up to 83% with 12 hr of HRT. Nitrification appeared to be the
limiting factor of nitrogen removal at an HRT that is less than 12 hr, indicating that the Yakult process requires more retention
time to achieve nitrification compared to other biofilm processes. The removal efficiencies of organics and solids were high
regardless of the change of operational parameters.
This article is based on a presentation in “The 7th Korea-China Workshop On Advanced Materials” organized by the Korea-China
Advanced Materials Cooperation Center and the China-Korea Advanced Materials Cooperation Center, held at Ramada Plaza Jeju
Hotel, Jeju Island, Korea on August 24–27, 2003. 相似文献
75.
Hyoun Woo Kim Kwang-sik Kim Woon-suk Hwang Rafael Reif 《Metals and Materials International》2002,8(5):463-467
We investigated the effect of the rinsing and drying technique on the oxygen and carbon concentration on a silicon surface.
Rinsing in deionized water increased the interfacial oxygen concentration and helped generate defects. Blow-drying was more
efficient than spin-drying in reducing interfacial oxygen concentration. Exposure to the atmosphere was detrimental to obtaining
high crystallinity in the epitaxial layer. We evaluated the effectiveness of the cleaning process by observing the grown epilayer
and the epilayer/substrate interface. 相似文献
76.
Galvanic coupling effect on the corrosion of SiC-reinforced aluminum alloy-matrix composites was investigated in a sodium chloride solution. The potentiodynamic polarization measurement indicated that pitting potentials of metal matrix composites (MMCs) and AA2124 matrix alloy were similar, and pitting potential of MMCs was almost same as corrosion potential, while pitting susceptibility of MMCs was higher than that of AA2124 alloy. Galvanic current by formation of galvanic couple between SiCw and matrix reveals very low value because of large cathodic polarization of SiC. However, by increasing potential of matrix to pitting potential by this galvanic couple and thus, forming pits easily at the weak passive film near SiC reinforcing phase preferentially, it is concluded that pitting susceptibility of MMCs increases highly than AA2124 alloy of matrix composition. 相似文献
77.
Jong-Hyun Hwang Myoung-Seoup Han Dae-Young Kim Joong-Geun Youn 《Journal of Materials Engineering and Performance》2006,15(3):328-335
High-temperature wear characteristics between plasma spray coated piston rings and cylinder liners were investigated to find
the optimum combination of coating materials using the disc-on-plate reciprocating wear test in dry conditions. The disc and
plate represented the piston ring and the cylinder liner, respectively. Coating materials studied were Cr2O3-NiCr, Cr2O3-NiCr-Mo, and Cr3C2-NiCr-Mo. Plasma spray conditions for the coating materials were established adjusting stand-off distance to obtain a coating
with a porosity content of ∼5%. It was found that a dissimilar coating combination of Cr2O3-NiCr-Mo and Cr3C2-NiCr-Mo provided the best antiwear performance. The addition of molybdenum was found to be beneficial to improve the wear
resistance of the coating. Hardness differences between mating surfaces were also important factors in determining the wear
characteristics, so that it should be controlled below 300 in Vickers hardness under dry conditions. Adhesive wear accompanying
with metal transfer was a dominant wear mechanism for dry conditions. 相似文献
78.
Jae Woong Choi Gil Ho Hwang Won Kyu Han Sung Goon Kang 《Metals and Materials International》2006,12(1):75-80
Ni−B film of 1 μm thickness was electrolessly deposited on an electroplated Cu bus electrode. The film, which encapsulates
the Cu bus electrodes, prevents Cu oxidation and serves as a diffusion barrier against Cu contamination of the transparent
dielectric layer in a plasma display during the firing process at 580 °C. The microstructure of theas-deposited barrier film was amorphous phase and crystallized to Ni and Ni3B after annealing at 300 °C. The good barrier properties observed here can be explained by Ni3B precipitates at the grain boundaries acting as a fast diffusion path via pre-annealing at 300 °C before the firing process
at 580 °C. 相似文献
79.
In-Gyu Park Chang-Soon Lee Seong-Sik Hwang Hong-Pyo Kim Joung-Soo Kim 《Metals and Materials International》2005,11(5):401-409
In order to evaluate the stress corrosion cracking resistance for commercial alloys (C600MA, C600TT, C690TT) and Korean-made
alloys (K600MA, K690TT), C-ring tests were performed in a caustic environment of 4, 10, 20, 30, and 50% NaOH solution at 315°C,
for 480 h with an applied potential of 125 mV vs. OCP. Different stress corrosion cracking phenomena were observed according
to the NaOH concentration. The rate of caustic IGSCC attack did not appear to increase monotonically with caustic concentrations,
but peaked at a concentration between 4 and 50% caustic, or approximately 30% NaOH. Intergranular stress corrosion cracking
was found for C600MA in 10, 20, and 30% NaOH solutions, while no cracking was observed in the 4 and 50% NaOH solutions. In
30% NaOH solution, transgrnular stress corrosion cracking was detected in C690TT, which may be related with the large amount
of plastic strain (150% yield) and the applied potential (125 mV vs. OCP). The overall data clearly indicate that C600MA has
the worst SCC resistance while K690TT offers the best resistance. There is also fairly good correlation between the caustic
SCC susceptibility and some metallurgical parameters, particularly the grain size and the yield strength at room temperature.
Specifically, materials having larger grain size and lower yield strength exhibited higher caustic SCC resistance. 相似文献
80.
A timing controller embedded driver IC with 3.24‐Gbps eDP interface for chip‐on‐glass TFT‐LCD applications 下载免费PDF全文
Tae‐Jin Kim Changhoon Baek Sengsub Chun Kil‐Hoon Lee Jong‐Il Hwang Kyeonghwan Kwon Yong‐Hun Kim Hyun‐Sang Park Youngmin Shin Seong‐young Ryu Jae‐Youl Lee Gyoocheol Hwang Gyeongnam Kim 《Journal of the Society for Information Display》2016,24(5):299-306
This paper presents a timing controller embedded driver (TED) IC with 3.24‐Gbps embedded display port (eDP), which is implemented using a 45‐nm high‐voltage CMOS process for the chip‐on‐glass (COG) TFT‐LCD applications. The proposed TED‐IC employs the input offset calibration scheme, the zero‐adjustable equalizer, and the phase locked loop‐based bang‐bang clock and data recovery to enhance the maximum data rate. Also, the proposed TED‐IC provides efficient power management by supporting advanced link power management feature of eDP standard v1.4. Additionally, the smart charge sharing is proposed to reduce the dynamic power consumption of output buffers. Measured result demonstrates the maximum data rate of 3.24 Gbps from a 1.1 V supply voltage with a 7.9‐inch QXGA 60‐Hz COG‐LCD prototype panel and 44% power saving from the display system. 相似文献