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Apiwat Muttamara Yasushi Fukuzawa Naotake Mohri Takayuki Tani 《Journal of Materials Processing Technology》2003,140(1-3):243-247
Electrical discharge machining (EDM) is used as a precision machining method for the electrically conductive hard materials with a soft electrode material. But recently we succeeded to machine on insulating material by EDM. The technology is named as an assisting electrode method. The EDMed surface is covered with the electrical conductive layer during discharge. The layer holds the electrical conductivity during discharge. For micro-EDM, the wear of tool electrode becomes lager ratio than the normal machining. So the micro-machining is extremely difficult to get the precision sample.
In this paper to obtain a fine and precise ceramics sample, some trials were carried out considering the EDM conditions, tool electrodes material and assisting electrode materials. Insulating Si3N4 ceramics were used for workpiece. The machining properties were estimated by the removal rate and tool wear ratio. To confirm the change of micro-machining process, the discharge waveforms were observed. The micro-machining of the Ø0.05 mm hole could be machined with the commercial sinking electrical discharge machine. 相似文献
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Apiwat Saengdeejing 《Automatica》2005,41(6):1079-1084
Robust control based on an online estimation of uncertainty is presented for a class of nonlinear uncertain systems. The estimation is done via a robust observer after the uncertainty vector is projected onto a one-dimensional subspace. The proposed combination of dynamics projection and online estimation is to relax the knowledge about the size of uncertainty and required in the robust control design, to make robust control less conservative while being effective, and to ensure robust stability without undue complexity. 相似文献
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Vichuda Sapa Sukanya Srijampa Patcharaporn Tippayawat Apiwat Chompoosor 《Journal of Inorganic and Organometallic Polymers and Materials》2017,27(4):979-985
Biofilms are complex bacterial communities have a mechanism for antibiotic resistance leading to human health problems. It remains challenging to treat and eradicate biofilms. In this work, the use of d-maltose synthesized silver nanoparticles (AgNPs) was investigated in an effort to eradicate a biofilm. AgNPs were synthesized using a modified Tollen’s method. d-maltose was used in synthesizing AgNPs with different concentrations of d-maltose (0.01, 0.05 and 0.1 M), referred to as NP1, NP2 and NP3, respectively. TEM images revealed that the particles were polygon shaped. The particle sizes were found to be 86.81?±?13.39, 54.94?±?11.63 and 31.43?±?31.76 nm depending on their sugar concentrations. UV–Vis, ATR–FTIR, and XRD patterns were employed to characterize the AgNPs. Then, these AgNPs were investigated for their anti-bacterial effects against Escherichia coli and Staphylococcus aureus. Evaluation of the minimum inhibitory concentration and minimal bactericidal concentration revealed that S. aureus was inhibited by all AgNPs and killed by NP1 and NP3, and E. coli was inhibited and killed at all AgNPs doses. Furthermore, anti-biofilm activity against these two bacteria was observed using SEM and confocal laser scanning microscopy. This sugar coated AgNPs is a promising material for use in eradication of biofilms. 相似文献
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H. Zhang S.L. Shang Y. Wang A. Saengdeejing L.Q. Chen Z.K. Liu 《Acta Materialia》2010,58(11):4012-4018
The elastic, phonon and thermodynamic properties of Al12Mg17 have been investigated by first-principles calculations. The obtained structural parameters, phonon dispersion curves and the predicted thermodynamic properties for all the phases studied herein agree well with available experimental data. The temperature-dependent single-crystal elastic constants are also predicted along with the polycrystalline aggregate properties, including bulk modulus, shear modulus, Young’s modulus, and Poisson’s ratio. The brittleness of Al12Mg17 that we predict is consistent with experiments, in contrast to the previous calculation showing ductile behavior. Detailed analysis of density of states further explains the present theoretical findings. 相似文献
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Saengdeejing Apiwat Qu Zhihua Chaeroenlap Nopphamas Jin Yufang 《Neural Processing Letters》2003,18(2):81-95
In this Letter, 2-D shape recognition is done using a combination of recursive search of landmarks, landmark-based invariant features, and a fuzzy ART neural-network classifier. To make this novel combination work well, an upper limit is imposed on the number of total landmarks allowed, and this maximum size is then translated into fixed dimensions of invariant features and into the neural processing of the features. It is shown that the recursive landmark search approximates very well any smooth 2-D shape contour, that the shape features used are independent of perspective transformation, and that, when combinedwitha fuzzy ART classifier, unknown features can be efficiently learned on-line to identify multiple distinct objects. An illustrative example is used to demonstrate effectiveness of the proposed algorithm. 相似文献
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Wattana Tuichai Saowalak Somjid Bundit Putasaeng Teerapon Yamwong Apiwat Chompoosor Prasit Thongbai Vittaya Amornkitbamrung Santi Maensiri 《Nanoscale research letters》2013,8(1):494
Non-Ohmic and dielectric properties of a novel CaCu3Ti4O12/Au nanocomposite were investigated. Introduction of 2.5 vol.% Au nanoparticles in CaCu3Ti4O12 ceramics significantly reduced the loss tangent while its dielectric permittivity remained unchanged. The non-Ohmic properties of CaCu3Ti4O12/Au (2.5 vol.%) were dramatically improved. A nonlinear coefficient of ≈ 17.7 and breakdown electric field strength of 1.25 × 104 V/m were observed. The maximum stored energy density was found to be 25.8 kJ/m3, which is higher than that of pure CaCu3Ti4O12 by a factor of 8. Au addition at higher concentrations resulted in degradation of dielectric and non-Ohmic properties, which is described well by percolation theory. 相似文献