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Chil-chyuan Kuo - One of the best experts on this subject based on the ideXlab platform.

  • Effects of pinhole diameters on beam characteristics for silicon thin film optical inspection
    Optik, 2012
    Co-Authors: Chil-chyuan Kuo, Jia-hao Lee, Yi-ruei Chen
    Abstract:

    Abstract Peak Power Density stability and beam-wander precision of probe laser are important factors affecting the inspection results in the precision thin film optical measurements. Pinhole is frequently used as a spatial filter in the optical inspection system. In this work, four different diameters of pinhole are investigated experimentally. It is found that pinhole diameter of 0.3 mm is considered to be a promising candidate for mounting in front of probe laser for silicon thin film optical inspection due to better Peak Power Density stability and better beam-wander precision.

  • The effects of pinhole diameter on beam stability of probe laser for precision thin-film optical inspection
    2011
    Co-Authors: Chil-chyuan Kuo, Yi-ruei Chen, Po-jen Huang
    Abstract:

    Five different diameters of pinhole are investigated experimentally. It is found that pinhole diameter of 0.3 mm is considered to be a promising candidate for mounting in front of probe laser for silicon thin-film optical inspection due to better Peak Power Density stability and better beam-wander precision.

  • Characterization of probe lasers for thin-film optical measurements
    Journal of Russian Laser Research, 2010
    Co-Authors: Chil-chyuan Kuo, Chin-sheng Chao
    Abstract:

    The Peak-Power-Density stability and beam-wander precision of a probe laser are important factors affecting the inspection results in precise thin-film optical measurements. These factors are also key to evaluating a probe laser for in-line long-time operation of precise thin-film optical measurements. The Peak-Power Density and beam wander of liner helium–neon (He–Ne) lasers, random He–Ne lasers, and diode lasers as functions of time are investigated experimentally using a beam profiler. It is found that the linear polarized He–Ne laser is considered to be a promising candidate for a probe laser employed in precise thin-film optical measurements due to better Peak-Power-Density stability and beam-wander precision. Both the Peak-Power-Density stability and beam-wander precision of He–Ne lasers are usually better than that of diode lasers, but an adequate warm-up of He–Ne laser for 30 min is required before thin-film optical measurements are made. After 12 h operation, the linear polarized He–Ne laser is suitable for precise thin-film optical measurements because both the Peak-Power-Density stability and the beam-wander precision reach the minimum level. A cost-effective system composed of two linear polarized He–Ne lasers for long-term operation is proposed. This system can operate for around 0.5–1.2 years in precise thin-film optical measurements under the normal operating life of a He–Ne laser by switching the probe laser every 18 h.

  • Evaluation of probe lasers employed in optical diagnostics for phase transformation of thin films during excimer laser crystallization
    Optics and Lasers in Engineering, 2008
    Co-Authors: Chil-chyuan Kuo
    Abstract:

    Abstract The stability and reliability of probe laser is an important factor affecting the inspection of the phase transformation process of Si thin films during excimer laser crystallization using in-situ time-resolved optical measurements. The changes in 2D intensity profile, Peak Power Density, and beam wander of the commonly used helium–neon (He–Ne) and diode laser are investigated experimentally. It is found that the Peak Power Density of He–Ne laser is higher than that of diode laser, while the total Power of He–Ne laser is lower than that of diode laser. Although the instability in the Peak Power Density of He–Ne laser will increase with increasing the operation time, the beam stability of He–Ne laser is better than that of diode laser. For long-time operation (>24 h) of optical measurements, the diode laser is a good candidate of probe laser. Conversely, the diode laser is suitable for the short-time operation (

Jia Wang - One of the best experts on this subject based on the ideXlab platform.

  • the fast optimal voltage partitioning algorithm for Peak Power Density minimization
    International Conference on Computer Aided Design, 2010
    Co-Authors: Jia Wang
    Abstract:

    Increasing transistor Density in nanometer integrated circuits has resulted in large on-chip Power Density. As a high-level Power optimization technique, voltage partitioning is effective in mitigating Power Density. Previous works on voltage partitioning attempt to address it through minimizing total Power consumption over all voltage partitions. Since Power Density significantly impacts thermal-induced reliability, it is also desired to directly mitigate Peak Power Density during voltage partitioning. Unfortunately, none of the existing works consider this. This paper proposes an efficient optimal voltage partitioning algorithm for Peak Power Density minimization. Based on novel algorithmic techniques such as implicit Power Density binary search, the algorithm runs in O(n log n + m2 log2 n) time, where n refers to the number of functional units and m refers to the number of partitions/voltage levels. Our experimental results on large testcases demonstrate that large amount of (about 9.7x) reduction in Peak Power Density can be achieved compared to a natural greedy algorithm, while the algorithm still runs very fast. It needs only 14.15 seconds to optimize 1M functional units.

  • ICCAD - The fast optimal voltage partitioning algorithm for Peak Power Density minimization
    2010 IEEE ACM International Conference on Computer-Aided Design (ICCAD), 2010
    Co-Authors: Jia Wang
    Abstract:

    Increasing transistor Density in nanometer integrated circuits has resulted in large on-chip Power Density. As a high-level Power optimization technique, voltage partitioning is effective in mitigating Power Density. Previous works on voltage partitioning attempt to address it through minimizing total Power consumption over all voltage partitions. Since Power Density significantly impacts thermal-induced reliability, it is also desired to directly mitigate Peak Power Density during voltage partitioning. Unfortunately, none of the existing works consider this. This paper proposes an efficient optimal voltage partitioning algorithm for Peak Power Density minimization. Based on novel algorithmic techniques such as implicit Power Density binary search, the algorithm runs in O(n log n + m2 log2 n) time, where n refers to the number of functional units and m refers to the number of partitions/voltage levels. Our experimental results on large testcases demonstrate that large amount of (about 9.7x) reduction in Peak Power Density can be achieved compared to a natural greedy algorithm, while the algorithm still runs very fast. It needs only 14.15 seconds to optimize 1M functional units.

Shingjiang Jessie Lue - One of the best experts on this subject based on the ideXlab platform.

  • Fumed Silica Nanoparticles Incorporated in Quaternized Poly(Vinyl Alcohol) Nanocomposite Membrane for Enhanced Power Densities in Direct Alcohol Alkaline Fuel Cells
    Energies, 2015
    Co-Authors: Selvaraj Rajesh Kumar, Cheng-hsin Juan, Guan-ming Liao, Jia-shiun Lin, Chun-chen Yang, Jiann-hua You, Shingjiang Jessie Lue
    Abstract:

    A nanocomposite polymer membrane based on quaternized poly(vinyl alcohol)/fumed silica (QPVA/FS) was prepared via a quaternization process and solution casting method. The physico-chemical properties of the QPVA/FS membrane were investigated. Its high ionic conductivity was found to depend greatly on the concentration of fumed silica in the QPVA matrix. A maximum conductivity of 3.50 × 10−2 S/cm was obtained for QPVA/5%FS at 60 °C when it was doped with 6 M KOH. The permeabilities of methanol and ethanol were reduced with increasing fumed silica content. Cell voltage and Peak Power Density were analyzed as functions of fumed silica concentration, temperature, methanol and ethanol concentrations. A maximum Power Density of 96.8 mW/cm2 was achieved with QPVA/5%FS electrolyte using 2 M methanol + 6 M KOH as fuel at 80 °C. A Peak Power Density of 79 mW/cm2 was obtained using the QPVA/5%FS electrolyte with 3 M ethanol + 5 M KOH as fuel. The resulting Peak Power densities are higher than the majority of published reports. The results confirm that QPVA/FS exhibits promise as a future polymeric electrolyte for use in direct alkaline alcoholic fuel cells.

  • Polytetrafluoroethylene (PTFE)/silane cross-linked sulfonated poly(styrene–ethylene/butylene–styrene) (sSEBS) composite membrane for direct alcohol and formic acid fuel cells
    Journal of Membrane Science, 2014
    Co-Authors: Bo-yan Wang, Chiyang Kevin Tseng, Chao-ming Shih, Yu-li Pai, Hsiu-po Kuo, Shingjiang Jessie Lue
    Abstract:

    Abstract A novel polymeric electrolyte membrane for direct alcohol fuel cells (DAFCs) and direct formic acid fuel cells (DFAFCs) was developed using a pore-filling method. This composite consisted of a porous polytetrafluoroethylene (PTFE) microporous substrate filled with silane-crosslinked sulfonated poly(styrene–ethylene/butylene–styrene) (sSEBS). This composite membrane was characterized using field emission scanning electron microscopy, Fourier-transform infrared spectrometry, thermal gravimetric analysis, and differential scanning calorimetry. The thermal and mechanical stabilities of this composite membrane were good. The methanol and ethanol permeabilities of this composite membrane were lower than Nafion 117, and these two membranes had comparable ionic conductivities. The Power densities in direct methanol fuel cells with this composite electrolyte were higher than with the Nafion electrolyte. A Peak Power Density of 91.4 mW cm −2 was achieved at 70 °C when the cell was fed with 0.5 M methanol. A direct ethanol fuel cell using this composite exhibited a Peak Power Density of 16.5 mW cm −2 at 60 °C. In a DFAFC, a Peak Power Density of 81.4 mW cm −2 was achieved with this composite and 3 M fuel at 60 °C. Long-term cell performance was sustained during a 180-h continuous operation using this pore-filled PTFE/sSEBS composite electrolyte. This PTFE/sSEBS composite membrane has potential for use in proton-exchange DAFC and DFAFC applications.

Matthew M. Mench - One of the best experts on this subject based on the ideXlab platform.

  • High Performance Vanadium Redox Flow Batteries with Optimized Electrode Configuration and Membrane Selection
    Journal of The Electrochemical Society, 2012
    Co-Authors: Qinghua Liu, Alexander B. Papandrew, Thomas A. Zawodzinski, G. M. Grim, A. Turhan, Matthew M. Mench
    Abstract:

    The performance of a vanadium flow battery with no-gap architecture was significantly improved via several techniques. Specifically, gains arising from variation of the overall electrode thickness, membrane thickness, and electrode thermal treatment were studied. There is a trade-off between apparent kinetic losses, mass transfer losses, and ionic resistance as the electrode thickness is varied at the anode and cathode. Oxidative thermal pretreatment of the carbon paper electrode increased the Peak Power Density by 16%. Results of the pretreatment in air showed greater improvement in Peak Power Density compared to that obtained with pretreatment in an argon environment. The highest Peak Power Density in a VRB yet published to the author s knowledge was achieved at a value of 767 mW cm 2 with optimized membrane and electrode engineering. 2012 The Electrochemical Society. [DOI: 10.1149/2.051208jes] All rights reserved.

N Chandrakumar - One of the best experts on this subject based on the ideXlab platform.

  • effect of varying poly styrene sulfonic acid content in poly vinyl alcohol poly styrene sulfonic acid blend membrane and its ramification in hydrogen oxygen polymer electrolyte fuel cells
    Journal of Membrane Science, 2008
    Co-Authors: Ak. Sahu, Santoshkumar D. Bhat, S. Pitchumani, A. K. Shukla, P Sridhar, G Selvarani, N Narayanan, Abhishek Banerjee, N Chandrakumar
    Abstract:

    Poly(styrene sulfonic acid) (PSSA) content in poly(vinyl alcohol) (PVA) and PSSA blend membrane is varied and its effect on proton conductivity is studied at varying relative humidity (RH) values. The maximum proton conductivity is observed for the PVA–PSSA membrane with about 35 wt. % PSSA at all humidity values. At 30% RH value, the conductivity of PVA–PSSA blend membrane is $1.20 \times 10^{-3} S/cm$, which is about two orders of magnitude higher than the conductivity value of $2.27 \times 10^{-5} S/cm$ observed for pristine PVA membrane. Water self-diffusion coefficients and water release kinetics of these materials have been characterized by nuclear magnetic resonance (NMR) imaging technique, which validate the use of this membrane in polymer electrolyte fuel cells (PEFCs). A Peak Power Density of $210 mW/cm^2$ at a load current-Density of $500 mA/cm^2$ is achieved for the PEFC with the optimized PVA–PSSA membrane as electrolyte compared to a Peak Power Density of only $38 mW/cm^2$ observed at a load current-Density of $80 mA/cm^2$ for the PEFC with pristine PVA membrane as electrolyte while operating at 75 °C with $H_2$ and $O_2$ feeds to the fuel cell maintained at atmospheric pressure.