• Proceedings of the KIEE Conference
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• 1994.07b
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• pp.1277-1279
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• 1994

In the structure of ZnO/nip-SiC: H/metal substrate amorphous silicon (a-Si:H) solar cells, the effects of inserting a rear textured ZnO in the p-SiC:H/metal interface and a graded bandgap buffer layer in the i/p-SiC:H have been analysed by computer simulation. The incident light was taken to have an intensity of $100mW/cm^2$(AM-1). The thickness of the a-Si:H n, ${\delta}$-doped a-SiC:H p, and buffer layers was assumed to be $200{\AA},\;66{\AA}$, and $80{\AA}$, respectively. The scattering coefficients of the front and back ZnO were taken to be 0.2 and 0.7, respectively. Inserting the rear buffer layer significantly increases the open circuit voltage($V_{oc}$) due to reduction of the i/p interface recombination rate. The use of textured ZnO markedly improves collection efficiency in the long wavelengths( above ${\sim}550nm$ ) by back scattering and light confinement effects, resulting in dramatic enhancement of the short circuit current density($J_{sc}$). By using the rear buffer and textured ZnO, the i-layer thickness of the ceil for obtaining the maximum efficiency becomes thinner(${\sim}2500{\AA}$). From these results, it is concluded that the use of textured ZnO and buffer layer at the backside of the ceil is very effective for enhancing the conversion efficiency and reducing the degradation of a-Si:H pin-type solar cells.

• Korean Journal of Metals and Materials
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• v.47 no.10
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• pp.681-685
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• 2009

$CeO_2$ buffer layers have been deposited on YSZ single crystal substrates via a radio-frequency sputtering method. We focused on the texture development of $CeO_2$ with out-of-plane alignment and its effects on a superconducting YBCO layer, which was deposited by metal organic deposition. $CeO_2$ layers were grown epitaxially on single crystal YSZ substrates and subsequent YBCO layers were also grown epitaxially from $CeO_2$ layers. It was observed that the intensity of $CeO_2$(200) decreased with deposition temperature. ${\theta}-2{\theta}$ scan FWHM values of $CeO_2$(200) were inversely proportional to the peak intensities of $CeO_2$(200). The sample with the lowest $CeO_2$(200) intensity and poor out-of-plane alignment showed a strong reaction with the MOD-YBCO layer resulting in a thicker $BaCeO_3$ layer. The texture and superconducting property of the YBCO layer were affected indirectly by the formation of a $BaCeO_3$ layer at the interface between the $CeO_2$ and YBCO layers.

• KSBB Journal
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• v.32 no.2
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• pp.103-107
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• 2017

The effect of the trehalose incorporation on the biological membranes was investigated with respect to the phase of the membranes using the fluorescence intensity change. Spherical phospholipid bilayers, vesicles, were prepared only with the variation in the phase of each layer via a double emulsion technique. In the aqueous inside of the vesicles, 8-Aminonaphthalene-1,3,6-trisulfonic acid disodium salt(ANTS) was encapsulated. As a quencher, p-Xylene-bis(N-pyridinium bromide)(DPX) was included in the buffer where the vesicles were dispersed. The fluorescence scale was calibrated with the fluorescence of ANTS vesicles in p-Xylene-bis(N-pyridinium bromide)(DPX)-included-buffer taken as 100% fluorescence and the mixture of ANTS and DPX in the buffer as 0% fluorescence. Trehalose injection into the vesicle solution led the distortion of the membrane. It was found that the distortion was related to the phase of each layer the vesicle up on the ratio of trehalose to lipid. In the identical measurements at glucose, the behavior of the distortion was completely different from that of trehalose. These results seem to depend on the stability of the vesicles, due to the osmotic and volumetric effects on the headgroup packing disruption.

• Journal of Plant Biology
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• v.36 no.3
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• pp.259-266
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• 1993

In Tris-iso-butanol (TIB; Tris buffer pH 8.8 and 1% iso-butanol)-treated chloroplasts, oxygen evolving activity was more inhibited than Tris-treated chloroplasts, but restored highly by 2,6-dichlorophenol-indophenol (DCPIP) and photoreactivation. To understand the mechanism of this results of TIB in photosynthetic electron transport, system, oxygen consumption and evolution of PS I and PS II were measured and protein of the chloroplasts was analysed. In Tris- and TIB-treated chloroplasts, oxygen evolving activity was increased according to the light intensity. Under 48 W·m-2 light intensity, the oxygen evolving activity in both chloroplasts were similar but as the light intensity was increased, TIB-treated chloroplasts showed higher activity. Under 240 W·m-2 light intensity, TIB-treated chloroplasts showed about 25% higher oxygen evolving activity than Tris-treated chloroplasts. Oxygen evolving activity was increased after photoreactivation in both Tris-treated and TIB-treated chloroplasts. Addition of NH4Cl increased the activity in both chloroplasts but in TIB-treated chloroplasts the increase was 30% higher than that in Tris-treated chloroplasts. In PS I, oxygen evolving activity was not inhibited by both treatments whereas in PS II, significant difference was observed between two treatments. Addition of Mn2+ and Ca2+ enhanced oxygen evolution in both Tris- and TIB-treated chloroplasts. Though enhancement was higher in TIB-treated chloroplasts. No difference was observed n protein analysis of the two thylakoid membrane.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.16 no.4
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• pp.326-334
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• 1991

We propose an optical Asynchronous Transfer Mode(ATM) switching system using free-space optics and an output buffer memory. The distributor system in the switching fabric was analyzed using the Huygens-Fresnel principle and lens transformation. For monochromatic illumination, a pattern similar to the Fourier transform of the input distribution was observed across the output plane. A spatially broadened intensity distribution across the the output plane can be expected when the system is illminated with a partially coherent, quasimonochromatic beam. Spatially coherent pulses as short as 100fs can propagate through the distributor without severe spatial broadening.

• Proceedings of the Materials Research Society of Korea Conference
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• 2003.11a
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• pp.174-174
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• 2003

ZnO는 상온에서 3.36 eV의 wide band gap과 60 meV의 큰 엑시톤 결합 에너지를 가지며, GaN(28 meV)와 ZnSe(19 meV)와 같은 wide band gap 재료와 비교해서 가장 우수한 exciton emission을 가진다. 이러한 특성 때문에 UV 레이저 및 LED와 같은 광학소자로서 그 응용의 잠재성이 높다. 박막의 우수한 광학적 특성과 결정성을 개선하기 위해 다양한 공정조건(RF 파워, 공정압력, 산소분압, 온도)에서 마그네트론 스퍼터링을 이웅하여 Si 기판상에 ZnO 박막을 성장 하였다. 또한, 저온 self-buffer를 이용하여 박막의 광학적 특성과 결정성을 더욱 개선 할 수 있었다. RF 파워와 공정압력은 박막의 PL(phothluminescehce) 특성이나 결정성에는 큰 영향을 주지 않았고 산소분압은 PL intensity의 변화를 가져왔으며, 온도는 결정성에 큰 영향을 주었다. 산소 분압이 증가 할수록 비화학량론적(산소 공공, 침입형 아연) 결함으로 인한 visiable 영 역의 peak 의 강도가 감소하는 것을 관찰하였다. 온도가 증가할수록 박막의 결정성에 나쁜 영향을 주었는데 저온 self-buffer를 도입하므로써 ZnO 박막의 결정성과 PL특성을 함께 개선하였다.

• Journal of the Korean Society of Physical Medicine
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• v.9 no.1
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• pp.45-53
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• 2014

PURPOSE: In this study, we tried to find out what kind of exercise was more effective in sleep disorder by comparing melatonin in blood after applying low intensity with high intensity exercise to sleep disordered rats induced by experiment. METHODS: We used male Sprague-Dawley rats which were 8weeks old and weighted 300g. They were supplied with water and food without any restriction. We kept the room temperature at $25^{\circ}C$ and controld the length of day and night in 12 hours blocks, respectively. We divided the rats 60 into 2 groups. To one group we applied low intensity exercise, and to the other we applied high intensity exercise for 15minutes per day over a period of 4 weeks. We extracted the blood from abdominal aorta before, after exercise, moved into EDTA tube, performed centrifugation. We decanted the serum $200{\mu}l$ from the blood into microcentrifuge tube by samples and moved into polypropylene culture tubes with micro pipette. We split enzyme solution $50{\mu}l$ into the tubes with melatonin direct kits and make them react at $37^{\circ}C$ for 2 hours. We split assay buffer $50{\mu}l$ into each tube and mixed melatonin tracer $50{\mu}l$ and melatonin antiserum $50{\mu}l$, respectively. After we made them react in room temperature, we decanted the superficial layer with a centrifuge and measured the activity for 1 minute by competitive method with ${\gamma}$-counter equipment. We draw a standard curve through logit-log graph with CPM(counts per minute) and counted the melatonin by B/B0. We conducted independent t-test to examine the homogeneous of melatonin value of before low-intensity and high-intensity exercise. We performed paired t-test to compare before and after low-intensity and high-intensity exercise, respectively. We carried out independent t-test to compare melatonin value after low-intensity and high-intensity exercise. Significance level was .05. RESULTS: The results were as follows; firstly melatonin was more increased in the group who was exposed to high intensity exercise when we compared before to after high and low intensity exercise, respectively. Secondly, high intensity exercise was more effective than low intensity exercise when we compared the two. CONCLUSION: In conclusion, secretion of melatonin which is the material of sleep improvement could be promoted by high intensity exercise. Low intensity exercise acted as a stress rather than improving sleep and had a negative effect on the secretion of melatonin because the melatonin was affected by stress.

• Journal of the Korean Vacuum Society
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• v.19 no.3
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• pp.211-216
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• 2010

The luminescence properties of $In_{0.5}Ga_{0.5}As/In_{0.5}Al_{0.5}As$ multiple quantum wells (MQWs) grown on $In_{0.5}Al_{0.5}As$ buffer layers have been studied by using photoluminescence (PL) and time-resolved PL measurements. A$1-{\mu}m$ thick $In_{0.5}Al_{0.5}As$ buffer layers were deposited on a 500 nm thick GaAs layer, followed by the deposition of the InGaAs/InAlAs MQWs. In order to investigate the effects of InAlAs buffer layer on the optical properties of the MQWs, four different temperature sequences are used for the growth of InAlAs buffer layer. The growth temperature for InAlAs buffer layer was varied from 320^{\circ}C to $580^{\circ}C$. The MQWs consist of three $In_{0.5}Ga_{0.5}$As wells with different well thicknesses (2.5 nm, 4.0 nm, and 6.0 nm thick) and 10 nm thick $In_{0.5}Al_{0.5}$As barriers. The PL spectra from the MQWs with InAlAs layer grown at lower temperature range ($320-580^{\circ}C$) showed strong peaks from 4 nm QW and 6 nm QW. However, for the MQWs with InAlAs buffer grown at higher temperature range ($320-480^{\circ}C$), the PL spectra only showed a strong peak from 6 nm QW. The strongest PL intensity was obtained from the MQWs with InAlAs layer grown at the fixed temperature of $480^{\circ}C$, while the MQWs with buffer layer grown at higher temperature from $530^{\circ}C$ to $580^{\circ}C$ showed the weakest PL intensity. From the emission wavelength dependence of PL decay times, the fast and slow decay times may be related to the recombination of carriers in the 4 nm QW and 6 nm QW, respectively. These results indicated that the growth temperatures of InAlAs layer affect the structural and optical properties of the MQWs.

• Bulletin of the Korean Chemical Society
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• v.15 no.5
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• pp.349-353
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• 1994

The CN radical was generated in a jet with an inert buffer gas, helium from high voltage dc discharge of the precursor $CH_3CN$. The Fourier transform emission spectra of the O-O band of the $(B^2{\Sigma}^+{\to}X^2{\Sigma}^+)$ transition of CN have been obtained with a Bruker IFS-120HR spectrometer. The spectra show an anomalous distribution of rotational intensity which cannot be explained by a simple Boltzmann distribution. The analysis of the transition frequencies provides molecular constants with high accuracy for both the ground and the excited electronic states of the CN radical.

• Journal of the Korean Operations Research and Management Science Society
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• v.39 no.3
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• pp.1-5
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• 2014

We study the paper Zhernovyi and Zhernovyi [Zhernovyi, K.Y. and Y.V. Zhernovyi, "An $M^{\Theta}/G/1/m$ system with two-threshold hysteresis strategy of service intensity switching," Journal of Communications and Electronics, Vol.12, No.2(2012), pp.127-140]. In the paper, authors used the Korolyuk potential method to obtain the stationary queue length distribution. Instead, our note makes an attempt to apply the most frequently used methods : the embedded Markov chain and the supplementary variable method. We derive the queue length distribution at a customer's departure epoch and then at an arbitrary epoch.