• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07b
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• pp.1010-1014
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• 2004

High quality GaN layer and $In_xGa_{1-x}N$ alloy were obtained on (0001)sapphire substrate using ammonia$(NH_3)$ and dimethylhydrazine$(DMH_y)$ as a nitrogen source by gas source molecular hem epitaxy(GSMBE) respectively. As a result, RHEED is used to investigate the relaxation processes which take place during the growth of GaN and $In_xGa_{1-x}N$. The full Width at half maximum of the x-ray diffraction(FWHM) rocking curve measured from Plane of GaN has exhibitted as narrow as 8 arcmin. Photoluminescence measurement of GaN and $In_xGa_{1-x}N$ were investigated at room temperature, where the intensity of the band edge emission is much stronger than that of deep level emission. In content of $In_xGa_{1-x}N$ epitaxial layer according to growth condition was investigated.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.25 no.10
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• pp.811-816
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• 2012

The effect of co-sputtering condition on the structural properties of $Mg_xZn_{1-x}O$ thin films grown by RF magnetron co-sputtering system was investigated for manufacturing ZnO/MgZnO structure LED. $Mg_xZn_{1-x}O$ thin films were grown with ZnO and MgO target varying RF power. Structural properties were investigated by X-ray diffraction (XRD) and Energy dispersive spectroscopy (EDS). The ZnO thin films have sufficient crystallinity on the high RF power. As RF power of ZnO target increased, the contents of MgO in the $Mg_xZn_{1-x}O$ film decreased. LED was manufactured using ZnO/MgZnO multi-layer on p-GaN/$Al_2O_3$ substrate. Threshold voltage of multi-layer LED was appeared at 8 V, and it was luminesced at wave length of 550 nm.

• Journal of The Korean Society of Inherited Metabolic disease
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• v.12 no.1
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• pp.49-53
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• 2012

X-linked adrenoleukodystrophy (ALD) is a rare inherited metabolic disease which results in impaired peroxisomal ${\beta}$-oxidation and the accumulation of very long chain fatty acids (VLCFA) in the adrenal cortex, the myelin of the central nervous system, and the testes. X-linked ALD is caused by mutations in the ABCD1 gene encoding an ATP-binding cassette transporter superfamily located in the peroxisomal membrane. This disease is characterized by a variety of phenotypes. The classic childhood cerebral ALD is a rapidly progressive demyelinating condition affecting the cerebral white matter before the age of 10 years in boys. We report the case of a 8-year-old with childhood cerebral X-linked ALD who developed inattention, hyperactivity, motor incoordination and hemiparesis. We diagnosed ALD with elevated plasma very long chain fatty acid level and diffuse high signal intensity lesions in both parieto-occipital white matter and cerebellar white matter in brain MRI. We identified a novel c.983delT (p.Met329CysfsX7) mutation of the ABCD1 gene. There is no correlation between X-ALD phenotype and mutations in the ABCD1 gene. Further studies for searching additional non-genetic factor which determine the phenotypic variation will be needed.

• Journal of Aquaculture
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• v.6 no.4
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• pp.295-310
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• 1993

As a part for the development of effective mass production techniqne of the puffer, Takifugu rubripes. seedfish, an investigation was carried out in 1989. 1991 and 1992 to determine the optimum starting feeding time of rotifers as a starting food for the fish larvae, and to find out the influences of the light intensitiy and LD cycles on the Artemia consumption by the larvae. The optimum starting time of feeding with rotifer. Brachionus Plicatilis was 2nd to 5th day from hatching resulting in survival of $96.5\~90.0\%$. Optimum light conditions for maximum feeding for fish larvae with Artemia were 1000 lux in 6mm, 600 lux in 8mm, and 200 lux in total length of 10-12 mm larvae. Relationship between total length (X: mm) of fish (6-12 mm in total length) and light intensity (Y: lux) for maximum feeding was:Y=2200-200X (r=-1.000). Relationship between days from hatching (X) and total length (Y: mm) of puffer fry was :Y=1.6427+0.2540X(r=0.9814) for 3 to 36 days after hatching, Y=-33.1452+1.1867X(r= 0.9854) for 36 to 68 days after hatching. Survival rate for 68 days after hatching was $24.1\%$ and the range of water temperature during this period was $21.25\pm1.67^{\circ}C$.

• Journal of the Korean Magnetics Society
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• v.8 no.4
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• pp.203-209
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• 1998

Crystallographic and magnetic properties of single phase garnet $Y_{3-x}Bi_xFe_5O_{12}$ (x=0.0, 0.25, 0.5, 0.75, 1.0) were studied by using x-ray diffraction, Mossbauer spectroscopy and vibrating sample magnetometer (VSM). Ultra-fine polycrystalline cubic samples have been prepared by sol-gel method. The lattice constant increase linearly with increasing an amount of Bi. Annealing temperature was larger than 800 $^{\circ}C$ for the growth of a single-phase garnet powder. The second phase of garnet, $(BiFeO_3)$, was at 1000 $^{\circ}C$ for x=0.75, and 950 $^{\circ}C$ for x=1.00. From Mossbauer spectroscopy and VSM measurements, the magnetization and the coercivity were decreased and the Curie temperature $Y_{3-x}Bi_xFe_5O_{12}$(x=0.0, 0.25, 0.5, 0.75, 1.0) was slightly increased as increasing the Bi content.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.4
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• pp.390-395
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• 2009

Design and optimization of a broadband meander-line twist reflector was performed for X-band application. Based on the equivalent transmission line model, the polarization twist performance was evaluated. Genetic analysis, particles swarm, and hybrid swarm optimizations were employed to obtain the optimized geometrical parameters. The optimized design exhibits low cross-polarization level below - 25 dB between 8.45 and 11.38 GHz. The polarization twist loss was below 0.2 dB. Comparison between computed and simulated results was also discussed.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.8 no.6
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• pp.9-14
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• 2008

Intentional city bands and public radio frequencies could reduce the internet transmission speed on the wired lines because AM and HF band are overlapping on the xDSL up and down data steam by way of the wired transmission lines. We were designed the adaptive common mode rejection circuit with 2 way amplifier against public radio frequency. Specially our circuits were applied for power and signal lines. We could reduced the common mode rejection up to 30dB and increased the up stream speed around 1.8 times using a our developed equipments. Also it could expanded the transmission distance up to 1.7 times than old lines.

• Analytical Science and Technology
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• v.10 no.3
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• pp.196-202
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• 1997

New vanadium(V) complex, $(NH_4)_2[VO_2NTA]$, has been synthesized and its structure has been determined by solution and solid-state NMR spectroscopies as well as X-ray crystallography. The unit cell of the monoclinic crystals contains four complexes with $a=6.923(1){\AA}$, $b=8.824(2){\AA}$, $c=19.218(11){\AA}$ and ${\beta}=91.60(3)^{\circ}$ in the space group of $P2_1/n$. The $[VO_2NTA]^{2-}$ anion has distorted octahedral geometry with cis-$VO_2$ moiety. It is confirmed that the octahedral geometry is retained in both of solution and solid-state complexes.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.11 no.5
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• pp.218-223
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• 2001

The chemical-mechanical polishing process was carried out for 2"-dia. sapphire wafer grown by horizontalBridgman method on the urethane lapping pad with the silica sol. The polished wafer shows the full-width at halfmaximum of 200~400 arcsec in double-crystal X-ray diffraction, indicating that the slicing, grinding and lapping processes before the polishing process affected the crystalline structural property of the wafer surface by the mechanical residual stress. For the inclusion of surface treatments after chemical-mechanical polishing such as the thermal annealing at the temperature of $1,200^{\circ}C$for 4 hrs. and chemical etching, the crystalline quality was sigdicantly enhanced with the reduced full-width at half maximum up to 8.3 arcsec.arcsec.

• Journal of the Korean Mathematical Society
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• v.8 no.1
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• pp.25-30
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• 1971

Put ($$^*$$) $$G[x,y]={\sum}\limits^{p+q=n}_{p,q=0}[-n]_{p+q}c_{p,q}x^py^q$$, where $[{\lambda}]_m$ is the Pocbhammer symbol and the $c_{p,q}$ are arbitrary constants. Making use of the specialized forms of some of his earlier results (see [8] and [9] the author derives here bilateral generating functions of the type ($$^{**}$$) $${\sum}\limits^{\infty}_{n=0}{\frac{[\lambda]_n}{n!}}_2F_1[\array{{\rho}-n,\;{\alpha};\\{\lambda}+{\rho};}x]\;G[y,z]t^n$$ where ${\alpha}$, ${\rho}$ and ${\lambda}$ are arbitrary complex numbers. In particular, it is shown that when G[y, z] is a double hypergeometric polynomial, the right-band member of ($^{**}$) belongs to a class of general triple hypergeometric functions introduced by the author [7]. An interesting special case of ($^{**}$) when ${\rho}=-m,\;m$ being a nonnegative integer, yields a class of bilateral generating functions for the Jacobi polynomials $\{P_n{^{{\alpha},{\beta}}}(x)\}$ in the form ($$^{***}$$) $${\sum\limits^{\infty}_{n=0}}\(\array{m+n\\n}\)P{^{({\alpha}-n,{\beta}-n)}_{m+n}(x)\;G[y,z]{\frac{t^n}{n!}}$$, which provides a unification of several known results. Further extensions of ($^{**}$) and ($^{***}$) with G[y, z] replaced by an analogous multiple sum $H\[y_1,{\cdots},y_m\]$ are also discussed.