Interface dynamics of table tennis

The purpose of this study was to discussed the Interface Dynamics of Table Tennis. The experiment was conducted based on the imaging principle of hot air flowing. We adopted the imaging principle of hot air flowing through rotating ball to simulate the flow phenomenon generated by air flowing through table tennis after striking by different rackets. The conclusion and suggestion after analyzing and discussing are described below: (1) The rotation of table tennis ball and flow field will change based on the roughness of rackets, which making its own contribution to the existence of changes in the rotation of table tennis ball. (2) It can learn that angle should forward 30 degrees with flat strike, 25 degrees with short particles and 20 degrees with long particles at the rotational speed of 7500 rpm. All flow fields of different rackets are similar

Imaginary polarization as a way to surmount the sign problem in ab initio calculations of spin-imbalanced Fermi gases

From ultracold atoms to quantum chromodynamics, reliable ab initio studies of strongly interacting fermions require numerical methods, typically in some form of quantum Monte Carlo calculation. Unfortunately, (non)relativistic systems at finite density (spin polarization) generally have a sign problem, such that those ab initio calculations are impractical. It is well-known, however, that in the relativistic case imaginary chemical potentials solve this problem, assuming the data can be analytically continued to the real axis. Is this feasible for nonrelativistic systems? Are the interesting features of the phase diagram accessible in this manner? By introducing complex chemical potentials, for real total particle number and imaginary polarization, the sign problem is avoided in the nonrelativistic case. To give a first answer to the above questions, we perform a mean-field study of the finite-temperature phase diagram of spin-1/2 fermions with imaginary polarization.Comment: 5 pages, 2 figures; published versio

Dye-Sensitized Solar Cells Using Mesocarbon Microbead-Based Counter Electrodes

The dye-sensitized solar cells (DSCs) equipped with mesocarbon microbead (MCMB)-based counter electrodes were explored to examine their cell performance. Three types of nanosized additives including platinum, carbon nanotubes (CNTs), and carbon black (CB) are well dispersed and coated over microscaled MCMB powders. In the design of the counter electrodes, the MCMB graphite offers an excellent medium that allows charge transfer from the ITO substrate to the dye molecule. The active materials such as Pt, CNT, and nanosize CB act as an active site provider for the redox reaction. Among these counter electrodes, the DSCs fabricated with CB electrode exhibit the highest power conversion efficiency. This improved efficiency can be attributed to the fact that the CB nanoparticles not only offer a large number of catalytic sites but also low charge transfer resistance, facilitating a rapid reaction kinetics. Such design of carbon counter electrode has been confirmed to be a promising candidate for replacing Pt electrodes

ESTIMATION THE PREFERENCE OF ECOTOURISM FOR GAOMEI WETLAND IN TAIWAN

Gaomei Wetland is not only the biggest grassy coastal wetland, but also a wild‐animal protecting area, located on the west‐central coast of Taiwan.Wetlands are considered as one of the most important natural resource, which offer a lot of benefits for human and other creatures. However, it is believed that over-intensive recreational activities in Gaomei Wetland should be responsible for serious damages on natural environment and ecosystem. This study takes Gaomei wetland as an example, and aims to estimate its landscape and ecological services values through Choice experiment. The results of this research showed that Gaomei landscape’s economic value is $2.06 million (USD) per year, and$1.54 million (USD) for its value of ecological services. These findings can help to bring up the awareness of natural resource preservation, and hopefully to keep Gaomei Wetland substantial. The results also indicated that visitors with undergraduate degree or above were willing to pay $6.43 (USD) per year for entry fee to enjoy sunset scenery in Gaomei wetland