National Cheng Kung University

About: National Cheng Kung University is a education organization based out in Tainan City, Taiwan. It is known for research contribution in the topics: Population & Thin film. The organization has 49723 authors who have published 69799 publications receiving 1437420 citations. The organization is also known as: NCKU.

A Different Form of Color Vision in Mantis Shrimp

Abstract: One of the most complex eyes in the animal kingdom can be found in species of stomatopod crustaceans (mantis shrimp), some of which have 12 different photoreceptor types, each sampling a narrow set of wavelengths ranging from deep ultraviolet to far red (300 to 720 nanometers) (1–3). Functionally, this chromatic complexity has presented a mystery (3–5). Why use 12 color channels when three or four are sufficient for fine color discrimination? Behavioral wavelength discrimination tests (Δλ functions) in stomatopods revealed a surprisingly poor performance, ruling out color vision that makes use of the conventional color-opponent coding system (6–8). Instead, our experiments suggest that stomatopods use a previously unknown color vision system based on temporal signaling combined with scanning eye movements, enabling a type of color recognition rather than discrimination.

Automated ontology construction for unstructured text documents

Abstract: Ontology is playing an increasingly important role in knowledge management and the Semantic Web. This study presents a novel episode-based ontology construction mechanism to extract domain ontology from unstructured text documents. Additionally, fuzzy numbers for conceptual similarity computing are presented for concept clustering and taxonomic relation definitions. Moreover, concept attributes and operations can be extracted from episodes to construct a domain ontology, while non-taxonomic relations can be generated from episodes. The fuzzy inference mechanism is also applied to obtain new instances for ontology learning. Experimental results show that the proposed approach can effectively construct a Chinese domain ontology from unstructured text documents.

Synthesis and Photoluminescence Characteristics of High Color Purity and Brightness Li3Ba2Gd3(MoO4)8:Eu3+ Red Phosphors

Abstract: The object of this study is to synthesize Li3Ba2Gd3(MoO4)8 doped with Eu3+ ions and prepared with solid-state reaction technology. The results show that the dominant emission peak of Li3Ba2Gd3−x(MoO4)8:Eux phosphor is 5D0 → 7F2 (614 nm). The intensity of the emission from 5D0 to 7F2 is 3.8 times higher than that of commercial phosphors, ZnS:(Mn2+,Te2+) when the Eu3+ concentration is x = 2.4. The CIE chromaticity coordinates of the red emission of the Li3Ba2Gd0.6Eu2.4(MoO4)8 phosphor are (0.67, 0.33), which is the NTSC system standard for red chromaticity. Because there are two regions in the excitation spectra of Li3Ba2Gd3(MoO4)8:Eu3+phosphor, one is assigned from the charge-transfer state (CTS) band at about 320 nm, and the other is from the intra-4f transitions from 350 to 500 nm. Hence, the phosphors could be strongly excited by near-UV and blue LED in solid-state lighting technology. The analysis of the lifetime, decay curves, and efficiency of the 5D0 → 7F2 emission indicates the weak energy transfer...

Effect of thickness on the structural and optical properties of ZnO films by r.f. magnetron sputtering

Abstract: In this study, the ZnO films were deposited to different thicknesses by r.f. magnetron sputtering. X-Ray diffraction and pole-figure analysis were used to study the crystallinity and crystal orientation. The results showed that ZnO films deposited to a thickness below 500 nm were polycrystalline with a c-axis preferential orientation. However, ZnO films, 500 or 600 nm in thickness, exhibited good self-texture. The optical properties of ZnO films did not depend significantly on the crystallographic orientation or degree of texturing. They were mainly affected by the grain size and carrier concentration.