National Central University was founded in 1915 with roots from 258 CE in mainland China. After NCU in Nanjing was renamed Nanjing University in 1949, NCU was re-established in Taiwan in 1962. The school was initially located in Miaoli, but was relocated to Zhongli in 1968, and developed into a comprehensive university. It has now become Taiwan's leading school in the fields of drama, film studies, cultural studies, sex and gender studies, Hakka studies, geophysics, space science, remote sensing, astronomy, optoelectronics, nano scitech, and business management. In 2001, NCU was selected by the Ministry of Education as one of the eleven research-oriented universities in Taiwan.NCU now has eight colleges in different areas, including College of Liberal Arts, College of Science, College of Engineering, College of Electrical Engineering and Computer Science, College of Biomedical Science and Engineering, College of Earth science, College of Management, and College of Hakka Studies, also with areas in sociology, law and government studies, etc. Wikipedia.
Vogel W.,National Central University
Journal of Physical Chemistry C | Year: 2011
We have used in situ X-ray diffraction and line profile analysis to study the carburization of a 6 nm Pd catalyst supported on carbon at various temperatures under helium, hydrogen, and oxygen. A maximum of 10% C atoms was dissolved in the Pd lattice. This phase is stable at ambient conditions but decays above 400 °C. The rate of formation is limited by active C from the support and is slower by a factor of ∼100 compared to the supply of C atoms via CO decomposition. The bulk diffusion coefficient predicts an even faster rate, demanding a surface barrier to activate bulk diffusion. We find that the rate of formation depends on the surface to volume ratio. Carbon is nonuniformly distributed among individual Pd particles, but hydrogen fills interstitial sites to lift the irregularity. In the ternary phase PdCxH y, x and y are linearly linked. Oxygen reacts with interstitial carbon already below 160 °C. © 2010 American Chemical Society.
Chang Y.-J.,National Central University
Optics Express | Year: 2010
A metal/multi-insulator/metal waveguide plasmonic Bragg grating with a large dynamic range of index modulation is investigated analytically and numerically. Theoretical formalism of the dispersion relation for the present and general one-dimensional gratings is developed for TM waves in the vicinity of each stop band. Wide-band and narrow-band designs with their respective FWHM bandwidths of 173.4 mn and < 3.4 mn in the 1550 nm band using a grating length of < 16.0 μm are numerically demonstrated. Time-average power vortexes near the silica-silicon interfaces are revealed in the stop band and are attributed to the contra-flow interaction and simultaneous satisfactions of the Bragg condition for the incident and backward-diffracted waves. An enhanced forward-propagating power is thus shown to occur over certain sections within one period due to the power coupling from the backward-diffracted waves. © 2010 Optical Society of America.
Ngeow C.-C.,National Central University
Astrophysical Journal | Year: 2012
In this paper, we explore the possibility of using the Wesenheit function to derive individual distances to Galactic Cepheids, as the dispersion of the reddening-free Wesenheit function is smaller than the optical period-luminosity (P-L) relation. When compared to the distances from various methods, the averaged differences between our results and published distances range from -0.061 to 0.009, suggesting that the Wesenheit function can be used to derive individual Cepheid distances. We have also constructed Galactic P-L relations and selected Wesenheit functions based on the derived distances. A by-product from this work is the derivation of Large Magellanic Cloud distance modulus when calibrating the Wesenheit function. It is found to be 18.531 0.043mag. © 2012. The American Astronomical Society. All rights reserved.
Huang C.M.,National Central University
Journal of Geophysical Research: Space Physics | Year: 2013
Perturbed electric fields in the Earth's ionosphere during storm activities may result from the penetration electric fields from high latitudes and/or from the dynamo mechanism driven by the neutral disturbances, depending on the storm phases. In general, the identification of the penetration electric fields is easier than that of the dynamo electric fields. At times, the latter becomes unperceivable or difficult to identify. This is an interesting problem that motivates a model study to investigate the possible reasons. Model runs made from the National Center for Atmospheric Research Thermosphere Ionosphere Electrodynamics General Circulation Model will be presented. Theoretical studies of ionospheric responses to geomagnetic storms with model simulations indicate that the intensities of disturbance dynamo electric fields are highly dependent on various parameters, for example, solar activities, seasonal effects and universal times, etc. When geomagnetic activities commence at 01 ~ 07 UT in summer solstices with low solar fluxes, the disturbance dynamo electric fields become very small. Compared with the general daily variations, they seem to be unperceivable. This phenomenon can be explained by the model results, which show that the positive charge accumulation at low latitudes will be weakened when the equatorward neutral disturbances penetrate the opposite hemisphere in the storm time. For other cases, the magnitudes of the dynamo electric fields are relatively larger under the same geomagnetic activities. © 2012. American Geophysical Union. All Rights Reserved.
Chiang C.-H.,National Central University
Nature Photonics | Year: 2016
An inverted bulk heterojunction perovskite–PCBM solar cell with a high fill factor of 0.82 and a power conversion efficiency of up to 16.0% was fabricated by a low-temperature two-step solution process. The cells exhibit no significant photocurrent hysteresis and their high short-circuit current density, fill factor and efficiency are attributed to the advantageous properties of the active layer, such as its high conductivity and the improved mobility and diffusion length of charge carriers. In particular, PCBM plays a critical role in improving the quality of the light-absorbing layer by filling pinholes and vacancies between perovskite grains, resulting in a film with large grains and fewer grain boundaries. © 2016 Nature Publishing Group