• Journal of IKEEE
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• v.27 no.4
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• pp.587-600
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• 2023

This paper presents an optimal design of the slim type high frequency transformer used in the LLC DC to DC resonant converter for 65-inch UHD-TV with the rated power of 315W. This paper also performs an optimal design of the slim type high frequency through core loss analysis, AC winding loss analysis, and optimization design of the winding arrangement of the LLC resonant transformer. Particularly, the high-efficiency and slim type high frequency transformer based on the obtained results from theoretical analysis in this paper is constructed in the interleaved and vertical winding structures of its transformer to realize the winding method of automatic type and minimize AC winding loss. The primary and secondary windings of the slim type high frequency transformer the vertical winding structure proposed in this paper used the Litz-wire windings, PCB and copper plate windings, respectively. Finally, an optimal design of the slim type high frequency transformer proposed in this paper was carried out through the experimental results to confirm the validity of theoretical analysis based on the simulation results using Maxwell 2D and 3D tool.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2003.10a
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• pp.46-49
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• 2003

Cu have been widely used as signal transmission materials for electrical electronic components owing to its high electrical conductivity. However, it's size have been limited to small ones due to its poor mechanical properties, Until now, strengthening of the copper at toy was obtained either by the solid solution and precipitation hardening by adding alloy elements or the work hardening by deformation process. Adding the at toy elements lead to reduction of electrical conductivity. In this aspect, if carbon nanofiber is used as reinforcement which have outstanding mechanical strength and electric conductivity, it is possible to develope Cu matrix nanocomposite having almost no loss of electric conductivity. It is expected to be innovative in electric conduct ing material market. The unidirectional alignment of carbon nanofiber is the most challenging task developing the copper matrix composites of high strength and electric conductivity In this study, the unidirectional alignment of carbon nanofibers which is used reinforced material are controlled by drawing process in order to manufacture the intermediary materials for the carbon nanofiber reinforced Cu matrix nanocomposite and align mechanism as well as optimized drawing process parameters are verified via experiments and numerical analysis. The materials used in this study were pure copper and the nanofibers of 150nm in diameter and of $10~20\mu\textrm{m}$ In length. The materials have been tested and the tensile strength was 75MPa with the elongation of 44% for the copper it is assumed that carbon nanofiber behave like porous elasto-plastic materials. Compaction test was conducted to obtain constitutive properties of carbon nanofiber. Optimal parameter for drawing process was obtained by experiments and numerical analysis considering the various drawing angles, reduction areas, friction coefficient, etc Lower reduction areas provides the less rupture of cu tube is not iced during the drawing process. Optimal die angle was between 5 degree and 12 degree. Relative density of carbon nanofiber embedded in the copper tube is higher as drawing diameter decrease and compressive residual stress is occurred in the copper tube. Carbon nanofibers are moved to the reverse drawing direct ion via shear force caused by deformation of the copper tube and alined to the drawing direction.

• Journal of fish pathology
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• v.30 no.2
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• pp.115-134
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• 2017

A total number of 668 apparently healthy fish were obtained from farm to study the effect of two heavy metals (Copper and Mercury) on histopathology of liver, kidney, spleen, gills and muscles also residues in muscles. The $LC_{50}$/96 hr. of Cu and Hg were estimated and fish exposed to 1/2 $LC_{50}$ for 7 days and for 1/10 $LC_{50}$ for 8 weeks from each product separately. Histopathological findings in acute and chronic mercuric chloride toxicity revealed degeneration and necrosis in the glomeruli, interstitium tissue and epithelium lining renal tubules. The tubular epithelium became necrotic at several places. Eosinophilic hyaline droplets is exist in the cytoplasm of the necrosed cells. Degenerative changes and hyperactivity in melanomachrophage center was seen in the spleen together with some necrotic areas. Necrosis and aggregation of melanomachrophage were seen in the hepatic cells, Hepatic cells showed vacuolar degeneration in the hepatic cells. Gills showed loss in the lamellae of the filaments associated with edema, inflammatory cells infiltration and haemorrhages in the arch. The sarcoplasm of the bundles of the skeletal muscle showed granular degeneration and focal inflammatory cells infiltration between the hyalinized bundles. Mercury residues obtained from these studies in the acute toxicity were 0.22 ppm/gm in the 2nd day, 0.411 ppm/gm in the $5^{th}$ day ended with 0.96 ppm/gm in the $7^{th}$ day. In chronic toxicity it was 1.1320, 1.7140, 2.3620 and 3.5640 ppm/gm respectively from the $2^{nd}$ to the $8^{th}$ week of exposure. In acute and chronic copper toxicity, there was degenerative changes in renal tubules. Melanophores aggregation in the wall of the blood vessels of the spleen and depletion of some of the melanophores in the melanomachrophage were seen together with necrosis in some areas. Congested Mvs (Micro vessels) and vacuolation of hepatocytes were observed. Some areas of hemorrhage and melanophores vacuolar degeneration in the liver were seen. There was mitosis in some areas with displesia of hepatopancreatic cells and eosinophilic granular cells aggregation. Zymogen granules disappeared and there were dyplastic hepatocytes. Congestion in the blood vessels of the gill filaments, associated with massive number of granular eosinophilic cells infiltration were seen in the base of the filaments. There were sever vacuolization and hyalinization in the skeletal muscle bundles. Detection of residues of copper sulfate revealed increase of the amount of copper measured in ppm/gm comparing to the normal control starting from 0.60 ppm/g in the $2^{nd}$ day, 0.67 ppm/g in the $5^{th}$ day and 0.67 ppm/g in the $7^{th}$ day. Result obtained in chronic copper sulfate toxicity revealed gradual increase of the amount of copper which ranged from 0.18 ppm/g at the $2^{nd}$ week to 0.21 ppm/g in the $8^{th}$ week of exposure.

• Bulletin of the Korean Chemical Society
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• v.33 no.8
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• pp.2679-2682
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• 2012

A simple one-pot synthesis of two derivatives of 1,4-dihydropyridines has been described under reflux conditions using copper iodide nanoparticles (CuI NPs) as a catalyst in high yields. This method demonstrated four-component coupling reactions of aldehydes and ammonium acetate via two pathways. In one route, the reaction was performed using 2 eq ethyl acetoacetate while in the other one 1 eq ethyl acetoacetate and 1 eq malononitrile were used. The CuI NPs was reused and recycled without any loss of activity and product yield. It is noteworthy to state that wide range of the 1,4-dihydropyridines have attracted large interest due to pharmacological and biological activities.

• Journal of environmental and Sanitary engineering
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• v.14 no.3
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• pp.71-79
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• 1999

The Hg, Cd, Cu, Mn, and Zn in bottom sediments of han river and their tributaries were analyzed to evaluate the seasonal variations of heavy metals. Leaching tests were also performed for estimation of availability of heavy metal retention in sediments. Sediments of Anyang stream showed the highest concentration of heavy metal in the sediment samples. Heavy metal concentration was heavily depended upon the heavy metal source of tributaries of han river and particle distribution. Clay and silt had higher concentration of heavy metals than very fine san and fine sand due to difference of retention capability of heavy metal. The highest concentration of heavy metal was observed in bottom sediments irrespective of sites investigated. Heavy metals and ignition loss showed positive relations, and higher relationships with p-value <0.01 were observed between copper and lead. copper and zinc, and depended on the pH condition of leaching test, and leachated fraction increased with decrease of the pH.

• BMB Reports
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• v.32 no.5
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• pp.440-444
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• 1999

Membrane lipid peroxidation processes yield reactive aldehydes that may react with copper,zinc superoxide dismutase (Cu,Zn SOD), one of the key antioxidant enzymes against oxidative stress. We investigated this possibility and found that exposing Cu,Zn SOD to malondialdehyde (MDA) or 4-hydroxynonenal (HNE) caused the loss of dismutase activity, cross-linking of peptides, and an increase in protein oxidation, reflected by the increased level of carbonyl groups. When Cu,Zn SOD that had been exposed to MDA or HNE was subsequently analyzed by amino acid analysis, histidine content was found to be significantly lost. Both MDA-and HNE-treated Cu,Zn SOD were resistant to proteolysis, which may imply that damaged proteins exist in vivo for a longer period of time than the native enzyme. The lipid peroxidation-mediated damage to Cu,Zn SOD may result in the perturbation of cellular antioxidant defense mechanisms, and subsequently lead to a pro-oxidant condition.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.19 no.2
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• pp.139-142
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• 2016

The coexistence of Wilson disease with Alport syndrome has not previously been reported. The diagnosis of Wilson disease and its ongoing monitoring is challenging when associated with an underlying renal disease such as Alport syndrome. Proteinuria can lead to low ceruloplasmin since it is among serum proteins inappropriately filtered by the damaged glomerulus, and can also lead to increased urinary loss of heavy metals such as zinc and copper. Elevated transaminases may be attributed to dyslipidemia or drug induced hepatotoxicity. The accurate diagnosis of Wilson disease is essential for targeted therapy and improved prognosis. We describe a patient with a diagnosis of Alport syndrome who has had chronic elevation of transaminases eventually diagnosed with Wilson disease based on liver histology and genetics.

• Journal of Power Electronics
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• v.14 no.5
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• pp.852-858
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• 2014

A novel 12/10 axial field switched reluctance motor (AF-SRM) is proposed for cooling fan applications in this paper. Unlike from conventional structures, the proposed motor uses the axial field instead of the radio field, the rotor is constructed from a series of discrete segments, and the stator poles are constructed from two types of stator poles: exciting and auxiliary poles. This concept improves the torque capability of a previous design by reducing the copper volume, which leads to a higher efficiency. To verify the proposed structure, the finite element method (FEM) and Matlab-Simulink are employed to get characteristics of the proposed SRM. Finally, a prototype of the proposed motor was tested for characteristic comparisons.

• Progress in Superconductivity and Cryogenics
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• v.7 no.3
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• pp.21-28
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• 2005

Superconducting synchronous motors and generators have the field coil composed of superconductor with almost zero resistance at superconducting state. Therefore, copper loss at the conventional field coil is eliminated and the superconducting machine gets higher efficiency. The armature coil of the superconducting machine is composed of copper wire and supported by non-magnetic material such as FRP (Fiber Reinforced Plastic) This paper contains the design Procedure of a 1MW superconducting synchronous motor using high-temperature superconductor only for the field coil. Especially, the armature coil is designed by water-cooling in order to dissipate Joule heat easily. Moreover, 3-dimensional electromagnetic design is conducted to get a proper design result and reduce design errors from 2-dimensional approach.

• Journal of the Korean Chemical Society
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• v.55 no.4
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• pp.603-611
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• 2011

Ethoxylacetyl oxime ligands [HL, (1) and $H_2L^1$, (3)] react with copper(II) acetate monohydrate yield octahedral and square planar complexes, respectively. The complexes have been postulated due to elemental analyses, IR, UVVis. spectra, magnetic susceptibility, conductivity and ESR spectra. Molar conductance of the complexes in DMF indicates a non-ionic character. The ESR spectra of [$(L)_2Cu(H_2O)_2$], (2) complex at room temperature and 77K are characteristic of an axial symmetry ($d_{x2-y2}$) with covalent bond character and have a large line width typical of dipolar interactions. However, [$(L^1)Cu$], (4) complex in the solid state showed spectra of marked broadening and loss of hyperfine splitting confirming spinexchange interactions between the copper(II) sites. The spectrum of the doped copper(II) complex at room temperature showed super-hyperfine splitting from coordinated nitrogen atoms and it has an axial type ($d_{x2-y2}$) with covalent bond character and an essentially square-planar arrangement around the copper(II) ion. The spectrum of [$(L^1)Cu$], (4) in frozen methanol at 77K was characteristic of the triplet state of a dimer species and the distance found between the two copper(II) centers was calculated and is equal to 4.8 ${\AA}$.