• Journal of Photoscience
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• v.3 no.3
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• pp.127-132
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• 1996

Calcium has a variety of functions in neuron and muscle cells and blood clotting, especially in the visual system where dark adapted rods cotransport with Na$^+$ into the cell. An influx of Ca$^{2+}$ flows out of the cell through the Na$^+$ - Ca$^{2+}$ exchanger. By using a modified Ussing chamber in order to bring in vivo environment close, we have concluded that Ca$^{2+}$ blocks the activity of guanylate cyclase; in consequence, having an effect on the amplitude of electroretinogram (ERG). We suggest that Ca$^{2+}$ moves between the photoreceptor and the vitreous humor by way of certain Ca$^{2+}$ transport mechanisms. Also, the effect of Zn$^{2+}$ in Ca$^{2+}$ - free ringer solution caused an elevation of amplitude in ERG and a reduction of threshold.

• Journal of the Korean Magnetics Society
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• v.3 no.2
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• pp.125-129
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• 1993

The magnetic properties of RF magnetron sputtered $Co_{79}Cr_{21}(at.%)$ thin film have been examined by using of ferromagnetic resonance. The properties of $Co_{79}Cr_{21}$ thin film show the effective first order anisotropy constant of $2.91{\times}10^{5}\;erg/cm^{3}$, the effective anisotropy field of 2526 Oe, and the spectroscopic splitting factor of 2.17. The torque experimental results, analyzed by employing modified Artman method, coincide with the ferromagnetic res-onance experimental results.

• Journal of the Korean Vacuum Society
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• v.3 no.3
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• pp.269-274
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• 1994

Tersoff 포텐셜을 사용한 에너지 최소화테크닉에 의하여 컴퓨터 시뮬레이션함으로써 다이아몬드 (100)과 (110) 표면의 구조와 표면에너지를 구하였다, 다이아몬드(100)면과 (110)면의 reconstruction pattern 은 각각 (1$\times$1)과 (2$\times$1)이며 표면에너지는 각각 6,671.3 erg/cm2 와 4,032.0 erg/cm2 인 것으로 계산되었다 (100)면의 surface reconstruction 은 첫 번째 원자층과 두 번째 원자층간의 간격이 [100] 방 향으로 수축되는 것으로 나타났다. 한편 (110)면의 surface reconstruc-tion은 주로 첫 번째 원자층에서 의 원자들은 [001] 방향으로 dimerization 한는 것과 첫 번째 원자층과 두 번째 원자층간의 간격이 [110] 방향으로 dimerization 하는 것과 첫 번째 원자층과 두 번째 원자층간의 간격이 [110] 방향으로 수축되 는 것으로 나타났다. 그밖에 표면의 각 원자층의 stress 성분들이 구해졌으며 그것들이 표면흡착에 미치 는 효과 등이 토의되었다.

• Proceedings of the KIEE Conference
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• 1994.07b
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• pp.1419-1421
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• 1994

The method of suppression based on the principle of energy trapping effect is very effective at high frequency. In this paper, We intended to get resonant frequency and bandpass filer characteristics in appling to vibration mode of PZT-4 and PZT-8 using trapped energy phenomenon. First, we theoretically analyzed a piezoelectric ceramic filter characteristics changing the thickness of ceramic plate, electrode spacing and distance between the two pairs of electrodes. We also experimentally investigated characteristics of ceramic filter made.

• Journal of the Korean Magnetics Society
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• v.2 no.2
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• pp.125-131
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• 1992

기판회전 테이블이 부착된 DC, RF-magnetron sputtering 장치로 유리기판 위에 제작한 1000 .angs. 정도의 8.8 .angs. Tb/X .angs. Fe (X=5.4~11.0) 다층박막에 관하여 시료진동형 자 기계와 타원편광 분석장치를 사용하여 자화, 수직자기이방성, kerr 회전각의 Fe층 두께와 열처리 온도 의존성이 연구되었다. Fe층 두께가 7.8 .angs. 기점으로하여 자화용이축의 전이가 나타나기 시작하여 6.4 .angs. 일때 수직자기이방성을 나타낸다. 실험치로부터 계산한 Fe와 Tb층의 경계면 수직이방성 에너지 $K_{s}$ = -0.38 erg/$cm^{2}$이고, Fe층만의 체적수직이방성 에너지 $K_{v}$ = -8.50 * $10^{5}$ erg/$cm^{3}$이다. Polar Kerr 회전각은 Fe층 두께 7.8 .angs. 에서 그대값 2 .THETA. $_{k}$ = 1.22 .deg. 를 갖는다.다.다.다.

• Journal of the Korean Magnetics Society
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• v.5 no.5
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• pp.372-375
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• 1995

The magnetization pattern of the central cross section deduced from the ac susceptibility measurement is described with an analytical function. The function is based on a charge-free configuration. The thickness of the $^{\circ}$ wall lying in a (100) plane and the wall energy are calculated analytically. Total energy of the domain structure has been minimized with Ritz's method. As the result of the minimization, the energy density of the $^{\circ}$ wall lying in a (100) plane is $0.58\;erg/cm^{2}$ and the one for a (110) plane is $1.18\;erg/cm^{2}$. Thicknesses of these walls are calculated numerically. Also, the calculation indicates there is a small central domain at the cross section without applied current. With the ac susceptibility measurement the existence of the domain without current can be identified.

• Proceedings of the PSK Conference
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• 2002.10a
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• pp.250.1-250.1
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• 2002

DA-8159. a selective inhibitor of phosphodiesterase type 5 (PDE5: IC$\sub$50/ 5ng/$m\ell$). is being developed as a new treatment for erectile dysfunction. Since DA-8159 has been shown to inhibit PDE6 enzyme (IC$\sub$53ng/$m\ell$). we evaluated the effect of DA-8159 on electroretinogram (ERG) and retinal histopathology in rabbits. The effect of oral DA-8159 (5 to 30mg/kg) on ERG recordings was investigated at pre-treatment. 1 and 5 hrs after administration in rabbits. (omitted)

• The Bulletin of The Korean Astronomical Society
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• v.45 no.1
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• pp.53.2-53.2
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• 2020

We measure X-ray timing and spectral properties of the pulsar PSR J0205+6449. Pulsar's rotation frequency ν = 15.20102357(9) s-1 and its derivative ${\dot{\nu}}=-4.5(1){\times}10^{-11}s^{-2}$ are measured, and the pulsed spectrum of 2-30 keV is model of power law with photon index ��psr = 1.07(16) and F2-30 keV = 7.3(6) × 10-13 erg cm-2 s-1. We use thermal emission models and non-thermal model to fit the pulsar spectrum and measure the surface temperature and luminosity of the pulsar. The surface temperature T∞ = 0.5-0.8 MK and luminosity Lth = 1-5 × 1032 erg s-1 are measure, and this result verifies the previous results known to have low surface temperature and luminosity for the age range of

• The Bulletin of The Korean Astronomical Society
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• v.36 no.2
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• pp.54.2-54.2
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• 2011

We present a study of HII regions in M51 using HST/ACS images taken as part of the Hubble Heritage Program. We found about 19,600 HII regions in M51 with $H_{\alpha}$ luminosity in the range of $L=10^{35.5}-10^{39.0}\;erg\;s^{-1}$. The $H_{\alpha}$ luminosity function of HII regions (HII LF) in M51 is well represented by a double power law with its index ${\alpha}=-2.25{\pm}0.02$ for the bright part and ${\alpha}=-1.42{\pm}0.01$ for the faint part, separated at a break point $L=10^{37.1}\;erg\;s^{-1}$. Comparison with simulated HII LFs suggests that this break is caused by the transition of HII region ionizing sources, from low-mass clusters (including several OB stars) to more massive clusters (including several tens of OB stars). The HII LFs with L < $10^{37.1}\;erg\;s^{-1}$ are found to have different slopes for different parts in M51: the HII LF for the interarm region is steeper than those for the arm and the nuclear regions. This observed difference in HII LFs can be explained by evolutionary effects: HII regions in the interarm region are relatively older than those in the other parts of M51. The size distribution of the HII regions is fitted by a double power law with a break at D = 30 pc. The power law index for the small HII regions with 15 pc < D < 30 pc is ${\alpha}=-1.78{\pm}0.04$, whereas ${\alpha}=-5.04{\pm}0.08$ for the large HII region with 30 pc < D < 110 pc. The power law indices of the size distribution are related with those of HII LF, and the relation between the luminosities and sizes of HII regions is fitted well by $L{\propto}D^{3.04{\pm}}$.

• Publications of The Korean Astronomical Society
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• v.30 no.2
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• pp.463-464
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• 2015

It has been suggested that only the most luminous AGNs ($L{\gtrsim}10^{45}erg/s$) are triggered by galaxy mergers, while less luminous AGNs ($L{\sim}10^{43}erg/s$) are driven by other internal processes. The lack of merging features in low luminosity AGN host galaxies has been a primary argument against the idea of merger triggering of low luminosity AGNs. But a merger, especially a rather minor one, might still have played an important role in low luminosity AGNs, as minor merging features at low luminosities are more difficult to identify than major merging features. Using SNUCAM on the 1.5 m telescope at Maidanak observatory, we obtained deep optical images of NGC 7743, a barred spiral galaxy classified as a Seyfert 2 AGN with a low bolometric luminosity of $5{\times}10^{42}erg/s$. Surprisingly, we discovered a merging feature around the galaxy, which indicates past merging activity in the galaxy. This example indicates that the merging fraction of low luminosity AGNs may be much higher than previously thought, hinting at the importance of galaxy mergers even in low luminosity AGNs.