Fine-scale genetic structure of rabbitfish, Siganus fuscescens, in Penghu Archipelago following a mass mortality event caused by extreme cold winter weather

Te‑Hua Hsu,Jin‑Chywan Gwo 한국유전학회 2017 Genes & Genomics Vol.39 No.6

In the winter of 2007–2008, a large number of fish were killed by chilling damage that occurred in the Pescadores (Penghu Archipelago). Such extreme weather events can cause rapid population changes, which provide an opportunity to understand the possible restoration mechanism of coral reef fishes in the Pescadores. The finescale genetic structure of the rabbitfish, Siganus fuscescens (Siganidae), was assessed using amplified fragment length polymorphism analysis. Significant genetic differences (lower gene flow) were observed between rabbitfish from the northern and southern parts of the Pescadores (Chenkong- Soukang, ΦST 0.075, P < 0.001) but not between those from the northern Pescadores and northeastern Taiwan (Chenkong-Keelung, ΦST 0.03, P > 0.02). The northern Pescadores and northeastern Taiwan have been shown to be relatively connected. The population structure of rabbitfish has complemented and helped support fish population recovery after several chilling events in the Pescadores.

Indentation deformation of mesoporous anodic aluminum oxide

Te-Hua Fang,Tong Hong Wang,Shao-Hui Kang,Cheng-Hsin Chuang 한국물리학회 2009 Current Applied Physics Vol.9 No.4

Mechanical properties of anodic aluminum oxides (AAO) were achieved by means of a scanning electron microscope (SEM), an atomic force microscope (AFM), and indentation measurements. A two-step anodized mesoporous anodic aluminum oxide was successfully fabricated vertically and hollowly. Both microindentation and nanoindentation were carried out. Localized pop-in can be found during nanoindentation due to the collapse of the beneath cylindrical structures. Over a certain load, microindentation may induce radial cracks from the indented edge to outward of the AAO. The underside of the indented AAO sample was milled to figure out the structural changes. Mechanical properties of anodic aluminum oxides (AAO) were achieved by means of a scanning electron microscope (SEM), an atomic force microscope (AFM), and indentation measurements. A two-step anodized mesoporous anodic aluminum oxide was successfully fabricated vertically and hollowly. Both microindentation and nanoindentation were carried out. Localized pop-in can be found during nanoindentation due to the collapse of the beneath cylindrical structures. Over a certain load, microindentation may induce radial cracks from the indented edge to outward of the AAO. The underside of the indented AAO sample was milled to figure out the structural changes.

Optical and physical characteristics of In-doped ZnO nanorods

Te-Hua Fang,Shao-Hui Kang 한국물리학회 2010 Current Applied Physics Vol.10 No.4

In this paper the effect of indium dopants on structure, optical, electrical and mechanical properties of ZnO nanorods are studied. The average surface potentials and the surface currents of ZnO:In nanorods were 0.25–0.84 mV and 2.2–200 MΩ-cm, respectively. The turn-on threshold field for the vertical ZnO nanorods was around 2–16 V ㎛-1. Emission current densities of 3.3–911.4 mA cm-2 were obtained for an electrical field of 60–160 V ㎛-1. The photoluminescence (PL) spectrum measured at 15–300 K showed that the intensity of the peak at 2.06 eV increased with decreasing temperature, while the peak at 2.06 eV further red shifted and the peak at 3.39 eV blue shifted.

MOLECULAR DYNAMICS ANALYSIS FOR FRACTURE BEHAVIOR OF GRAPHENE SHEETS WITH V-SHAPED NOTCHES UNDER TENSION

Te-Hua Fang,Win-Jin Chang,Kai-Peng Lin,CHENG-I WENG 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2014 NANO Vol.9 No.8

Molecular dynamics (MD) simulations are performed to study the fracture behavior of armchair and zigzag graphene sheets with V-shaped notches subjected to tensile loading. The effects of temperature and notches depth on the fracture characteristics of the graphene sheets are examined. The results show that the cracks propagate from the notch tip along the direction perpendicular to the loading axis for armchair sheets. This is different from the zigzag graphene propagating along the direction of 45˚ from the loading axis. In addition, the fracture energy of zigzag graphene sheets is larger than armchair one at the same temperature condition.

Stability and wrinkling of defective graphene sheets under shear deformation

Te-Hua Fang,Win-Jin Chang,Kai-Peng Lin,Siu-Tsen Shen 한국물리학회 2014 Current Applied Physics Vol.14 No.4

The molecular dynamic simulation is performed to study the wrinkling behavior of a graphene sheet with a hole subjected to a shear loading at different temperatures. Wrinkling is inevitable under pure shear loading. Four different hole diameters of 0, 0.8, 1.6, and 3.2 nm are chosen in this simulation. The results show that the number of ridges increases with an increase of the width of the graphene sheet. The shear stress induced in the defective graphene sheet increases with increasing temperature. In addition, the shear modulus of the defective graphene sheet also increases with an increase of temperature.

Effect of nitrogen doping on nanomechanical and surface properties of silicon film

Te-Hua Fang,Win-Jin Chang,Shao-Hui Kang,Jia-Hung Liou 한국물리학회 2009 Current Applied Physics Vol.9 No.6

The effect of nitrogen ion implantation on the nanomechanical properties of single crystal Si was evaluated by means of a conventional Vickers indentation and nanoindentation tests. The images of Si surfaces before and after nitrogen implantation were observed and their average surface roughnesses were measured by an atomic force microscope (AFM), while the changes in the morphology and microstructure of the single crystal Si by N implantation were examined by field emission scanning electron microscope (SEM) and X-ray diffractometer (XRD). In addition, the hydrophilic/hydrophobic surface property of the N-doping Si film was determined from the measurement of water contact angle by the sessile drop technique. Furthermore, the effects of the doping energy on the surface contact angle and the surface roughness and the Vickers hardness of the film are also investigated. The effect of nitrogen ion implantation on the nanomechanical properties of single crystal Si was evaluated by means of a conventional Vickers indentation and nanoindentation tests. The images of Si surfaces before and after nitrogen implantation were observed and their average surface roughnesses were measured by an atomic force microscope (AFM), while the changes in the morphology and microstructure of the single crystal Si by N implantation were examined by field emission scanning electron microscope (SEM) and X-ray diffractometer (XRD). In addition, the hydrophilic/hydrophobic surface property of the N-doping Si film was determined from the measurement of water contact angle by the sessile drop technique. Furthermore, the effects of the doping energy on the surface contact angle and the surface roughness and the Vickers hardness of the film are also investigated.

Molecular dynamics study of the shear strength and fracture behavior of nanoporous graphene membranes

Te-Hua Fang,Zhe-Wei Lee,Win-Jin Chang 한국물리학회 2017 Current Applied Physics Vol.17 No.10

We perform molecular dynamics (MD) simulations to study the structural response and fracture characteristics of nanoporous graphene (NPG) membranes subjected to shear loading. The effects of porosity, temperature, and shear velocity on the mechanical responses of NPG membranes are examined. The results show that the wrinkling of the membrane becomes more obvious with increasing strain. Fractures occur around holes on the long diagonal of the NPG parallelogram, and fracture stress in the NPG membrane decreases with increasing porosity. In addition, the effect of shear velocity on the shear modulus decreases with increasing porosity. The fracture strain of NPG membranes with different porosities obviously decreases with increasing temperature. The results enhance our understanding of the shear mechanical properties of NPG membranes and are helpful for the design and application of highperformance NPG membranes.

Frictional Characteristics of Graphene Layers Using Molecular Dynamics Simulation

Te-Hua Fang,Win-Jin Chang,Fu-Yung Tung 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2016 NANO Vol.11 No.9

Molecular dynamics simulations of an atomic force microscope (AFM) probe scanning the surface of a five-layer graphene were conducted. The AFM-like scanning probe was modeled by a capped single-wall carbon nanotube. Note that interference with the graphene surface induced frictional behavior; moreover, the effects on the friction system of scanning velocity, probe direction and temperature were investigated. Wrinkling of the graphene surface became more apparent at higher temperatures, while stick-slip friction was more apparent at a lower temperature and a slower scanning velocity. The friction coefficient of the system was approximately 0.001.

Tracing the origin of fish without hatchery information: genetic management of stock enhancement for mangrove red snapper (Lutjanus argentimaculatus) in Taiwan

Hsu, Te-Hua,Huang, Chang-Wen,Lin, Cheng-Hui,Lee, Hung-Tai,Pan, Chieh-Yu The Korean Society of Fisheries and Aquatic Scienc 2020 Fisheries and Aquatic Sciences Vol.23 No.5

Stock enhancement is considered to be a valuable approach for restoring fishery resources. Because no specific official institution in Taiwan is responsible for the production of fry, the released fry are purchased directly from the private sector. However, fishermen from the private industry have not established a genetic background, so the genetic composition for each batch of released fry is unclear. Mangrove red snapper (Lutjanus argentimaculatus), a prominent species released in Taiwan, was collected after its official release. One hundred and two field samples were compared with four batches of hatchery fry (n = 685) by using a microsatellite-based multiplex PCR assay. Four of the field samples (3.9%; 4/102) were revealed to be from a fish farm and most likely from a single batch. This study revealed that wild mangrove red snappers are genetically different from those originating from farms, and their origins can be traced through molecular markers, even without information on breeding stocks.

Tracing the origin of fish without hatchery information: genetic management of stock enhancement for mangrove red snapper (Lutjanus argentimaculatus) in Taiwan

Hsu Te-Hua,Huang Chang-Wen,Lin Cheng-Hui,Lee Hung-Tai,Pan Chieh-Yu 한국수산과학회 2020 Fisheries and Aquatic Sciences Vol.23 No.2

Stock enhancement is considered to be a valuable approach for restoring fishery resources. Because no specific official institution in Taiwan is responsible for the production of fry, the released fry are purchased directly from the private sector. However, fishermen from the private industry have not established a genetic background, so the genetic composition for each batch of released fry is unclear. Mangrove red snapper (Lutjanus argentimaculatus), a prominent species released in Taiwan, was collected after its official release. One hundred and two field samples were compared with four batches of hatchery fry (n = 685) by using a microsatellite-based multiplex PCR assay. Four of the field samples (3.9%; 4/102) were revealed to be from a fish farm and most likely from a single batch. This study revealed that wild mangrove red snappers are genetically different from those originating from farms, and their origins can be traced through molecular markers, even without information on breeding stocks.