National Tsing Hua University

About: National Tsing Hua University is a education organization based out in Hsinchu, Taiwan. It is known for research contribution in the topics: Thin film & Layer (electronics). The organization has 39811 authors who have published 50379 publications receiving 1100284 citations. The organization is also known as: NTHU.

Coverage‐based rarefaction and extrapolation: standardizing samples by completeness rather than size

Abstract: We propose an integrated sampling, rarefaction, and extrapolation methodology to compare species richness of a set of communities based on samples of equal completeness (as measured by sample coverage) instead of equal size. Traditional rarefaction or extrapolation to equal-sized samples can misrepresent the relationships between the richnesses of the communities being compared because a sample of a given size may be sufficient to fully characterize the lower diversity community, but insufficient to characterize the richer community. Thus, the traditional method systematically biases the degree of differences between community richnesses. We derived a new analytic method for seamless coverage-based rarefaction and extrapolation. We show that this method yields less biased comparisons of richness between communities, and manages this with less total sampling effort. When this approach is integrated with an adaptive coverage-based stopping rule during sampling, samples may be compared directly without rarefaction, so no extra data is taken and none is thrown away. Even if this stopping rule is not used during data collection, coverage-based rarefaction throws away less data than traditional size-based rarefaction, and more efficiently finds the correct ranking of communities according to their true richnesses. Several hypothetical and real examples demonstrate these advantages.

A Review of CO2 Capture by Absorption and Adsorption

Abstract: Global warming resulting from the emission of greenhouse gases, especially CO2, has become a widespread concern in the recent years. Though various CO2 capture technologies have been proposed, chemical absorption and adsorption are currently believed to be the most suitable ones for post-combustion power plants. The operation of the chemical absorption process is reviewed in this work, together with the use of absorbents, such as the ionic liquid, alkanolamines and their blended aqueous solutions. The major concerns for this technology, including CO2 capture efficiency, absorption rate, energy required in regeneration, and volume of absorber, are addressed. For adsorption, in addition to physical adsorbents, various mesoporous solid adsorbents impregnated with polyamines and grafted with aminosilanes are reviewed in this work. The major concerns for selection of adsorbent, including cost, adsorption rate, CO2 adsorption capacity, and thermal stability, are compared and discussed. More effective and less energy-consuming regeneration techniques for CO2-loaded adsorbents are also proposed. Future works for both absorption and adsorption are suggested.

Recent progress in high-entropy alloys

Abstract: Progres recents dans les alliages a haute entropie. La trentaine de systemes d'alliages actuellement d'utilisation courante sont typiquement bases sur un ou, au plus, deux elements. On considerait que des alliages constitues d'un plus grand nombre d'elements principaux formeraient des microstructures compliquees et fragiles, et la recherche sur de tels alliages multielementaires a donc ete tres limitee. Cependant, en 1995, Yeh a suggere que les systemes d'alliages formes d'au moins cinq elements metalliques possedaient des entropies de melange elevees et favoriseraient donc la formation de solutions solides multielementaires, par opposition aux supposees structures complexes formees de nombreux composes intermetalliques. Les travaux effectues au cours de la derniere decennie sur de tels alliages multielementaires, denommes de facon appropriee « alliages a haute entropie » (AHE), ont en effet montre que ces derniers formaient des phases simples a structures nanocristallines et meme amorphes. Outre l'effet de haute entropie, ces caracteristiques structurales ont ete attribuees a l'existence dans ces melanges multielementaires de fortes distorsions de reseau et d'une diffusion ralentie. En fonction de leur composition et du procede d'elaboration, il s'est avere que les AHE presentaient un large spectre de microstructures et de proprietes. Les proprietes superieures de certains AHE par rapport aux alliages classiques, ainsi que le nombre enorme de combinaisons possibles susceptibles de conduire a des phenomenes nouveaux et a des applications fonctionnelles, font que ces AHE presentent un grand interet non seulement du point de vue de la recherche mais aussi pour de nombreuses applications industrielles. Dans cette perspective, cet article passe en revue les progres recents dans les AHE et les orientations futures.