Yeungnam University

About: Yeungnam University is a education organization based out in Daegu, South Korea. It is known for research contribution in the topics: Thin film & Catalysis. The organization has 9885 authors who have published 22075 publications receiving 372798 citations.

On Hyperbolic Heat Conduction and the Second Law of Thermodynamics

Abstract: For situations in which the speed of thermal propagation cannot be considered infinite, a hyperbolic heat conduction equation is typically used to analyze the heat transfer. The conventional hyperbolic heat conduction equation is not consistent with the second law of thermodynamics, in the context of nonequilibrium rational thermodynamics. A modified hyperbolic type heat conduction equation, which is consistent with the second law of thermodynamics, is investigated in this paper. To solve this equation, we introduce a numerical scheme from the field of computational compressible flow. This scheme uses the characteristic properties of a hyperbolic equation and has no oscillation. By solving a model problem, we show that the conventional hyperbolic heat conduction equation can give physically wrong solutions (temperature less than absolute zero) under some conditions. The modified equation does not display these erroneous results. However, the difference between results of these two models is negligible except under extreme conditions.

Advanced Fault Ride-Through Technique for PMSG Wind Turbine Systems Using Line-Side Converter as STATCOM

Abstract: In this paper, a hybrid control scheme for energy storage systems (ESS) and braking choppers for fault ride-through capability and a suppression of the output power fluctuation is proposed for permanent-magnet synchronous generator (PMSG) wind turbine systems. During grid faults, the dc-link voltage is controlled by the ESS instead of the line-side converter (LSC), whereas the LSC is exploited as a STATCOM to inject reactive current into the grid for assisting in the grid voltage recovery. The validity of the proposed system is verified by experimental results for a reduced-scale wind turbine simulator as well as simulation results for a 2-MW PMSG wind turbine system.

The Ascending Reticular Activating System from Pontine Reticular Formation to the Thalamus in the Human Brain

Abstract: Introduction: Action of the ascending reticular activating system (ARAS) on the cerebral cortex is responsible for achievement of consciousness. In this study, we attempted to reconstruct the lower single component of the ARAS from the reticular formation (RF) to the thalamus in the normal human brain using diffusion tensor imaging (DTI). Methods: Twenty six normal healthy subjects were recruited for this study. A 1.5-T scanner was used for scanning of diffusion tensor images, and the lower single component of the ARAS was reconstructed using FMRIB software. We utilized two ROIs for reconstruction of the lower single component of the ARAS: the seed ROI - the RF of the pons at the level of the trigeminal nerve entry zone, the target ROI - the intralaminar nuclei of the thalamus at the level of the commissural plane. Results: The reconstructed ARAS originated from the pontine RF, ascended through the mesencephalic tegmentum just posterior to the red nucleus, and then terminated on the intralaminar nuclei of the thalamus. No significant differences in fractional anisotropy, mean diffusivity, and tract number were observed between hemispheres (P>0.05) Conclusion: We reconstructed the lower single component of the ARAS from the RF to the thalamus in the human brain using DTI. The results of this study might be of value for the diagnosis and prognosis of patients with impaired consciousness

The Growth Mechanism of Nickel Oxide Thin Films by Room-Temperature Chemical Bath Deposition

Abstract: Chemical bath deposition (CBD) is an advantageous thin film deposition technique for depositing compound semiconductors at low temperature. In this paper, nickel oxide thin films were prepared by CBD from an aqueous solution composed of nickel sulfate, potassium persulfate, and ammonia at room temperature. Thin film growth mechanisms were studied by using quartz crystal microbalance, UV-vis absorption, and photon correlation spectroscopy. The data indicate that film growth is strongly dependent upon mixing conditions and competes with homogeneous particle formation. No film formation was observed without the addition of persulfate. A growth mechanism based on the combination of particle sticking and molecule level heterogeneous growth is proposed. The as-deposited film contained α-Ni(OH) 2 and 4Ni(OH) 2 ·NiOOH·xH 2 O and was converted to nickel oxide (NiO) by thermal annealing according to thermogravimetric. X-ray diffraction and X-ray photoelectron spectroscopy measurements.

Genome sequence and analysis of the Japanese morning glory Ipomoea nil.

Abstract: Ipomoea is the largest genus in the family Convolvulaceae. Ipomoea nil (Japanese morning glory) has been utilized as a model plant to study the genetic basis of floricultural traits, with over 1,500 mutant lines. In the present study, we have utilized second- and third-generation-sequencing platforms, and have reported a draft genome of I. nil with a scaffold N50 of 2.88 Mb (contig N50 of 1.87 Mb), covering 98% of the 750 Mb genome. Scaffolds covering 91.42% of the assembly are anchored to 15 pseudo-chromosomes. The draft genome has enabled the identification and cataloguing of the Tpn1 family transposons, known as the major mutagen of I. nil, and analysing the dwarf gene, CONTRACTED, located on the genetic map published in 1956. Comparative genomics has suggested that a whole genome duplication in Convolvulaceae, distinct from the recent Solanaceae event, has occurred after the divergence of the two sister families. Japanese morning glory (Ipomoea nil) has diverse flowering traits. Here, the authors describe the reference genome sequence of I. nil, annotations of genes and transposons, and compare evolution of the I. nilgenome to other Convolvulaceae and Solanales genomes.