• Journal of Plant Biology
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• v.25 no.1
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• pp.21-36
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• 1982

The activity of photosystem II in isolated chloroplast form the leaves of Sedum sarmentosum was measured. The photoreduction rate of DCPIP by photosystem II showed the circadian rhythm with a peak at near midday sample for a continuing fine day and at near afternoon between nidday and sunset sample for a continuing cloudy day in summer. The optimum light intensity of photoreduction by photosystem II in the chloroplast preparation was about 5~9$\times$$10^4$ lux. The saturated light intensity was over 9$\times$$10^1$lux. Photosystem II activity was inhibited by even the lowest concentration of lead. When Pi and ATP of the same concentration as Pb were added to the reaction mixture containing Tris buffer lacking of Pi prior to Pb incubation, photosystem II activity was protected from Pb-inhibiting effect by the pretreament of Pi and ATP. It was assumed that Pb inhibiiton was probably due to one, P-depriving by the precipitates of $Pb_3$ $($Pb_4$)_2$ in the reaction mixture and the other, partially Pb-combing with Pi groups of the active site of photosystem II.

• Journal of the Korean Vacuum Society
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• v.5 no.3
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• pp.258-262
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• 1996

We have investigated the changes in magnetoresistive characteristics, interfacial roughness, and preferred orientation with the Fe buffer layer thickness, annealing temperature, and the stacking number of layers variation in Fe/[NiFe/Cu] multilayers by using the 3-gun d.c. magnetron sputtering method. Intensity of the (200) orientation was increased with the increment of the Fe-buffer layer thickness. We found a maximum magnetoresistance ration of 4.7%, when the buffer layer thickness was 70$\AA$, and the field sensitivity also showed a maximum value at the same thickness. We varied the stacking number of multilayers with fixing the Fe buffer layer thickness of 70$\AA$. When the stacking number was 40 layers, maximum MR ratio(5.3%) was observed. With the variation of annealing temperature no change in the MR ratio was found beyond $300^{\circ}C$. But decrement of MR ratio was observed above $300^{\circ}C$. This decrement of the MR ratio was responsible for the increment of paramagnetic mixed layer caused by the diffusion of Cu layer and the change of antiferromagnetic coupling.

• Journal of the Mineralogical Society of Korea
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• v.15 no.2
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• pp.114-121
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• 2002

Buffer capacities for two Bo horizon soils or Andisols developed from different parent materials have been investigated. The titration curves from column leaching experiment show that buffering occurred at pH 4.0 and 6.0. The buffer intensity or soil developed from pyroclastic materials (P-soil) is higher than that from basalts (B-soil). From batch test we have found that proto-imogolite and/or imogolite may control Al solubility as well as $Al(OH) _3$in the moderate acid condition. The buffer intensities ($\beta$) of P-soils were plotted on the theoretical buffering curve of $Al(OH)_3$, while $\beta$ of B-soils approached to that of proto-imogolite, which shows the solubility of short-range-order materials in P-soil control the buffer capacity. Buffering at pH 6.0 is thought to be the result of dissolution of some silicate clays and exchange reactions between $H^{+ }$and base-forming cations. Considering the amount of annual acid precipitation, aluminum solubility of Andisols, and the low BS (Base Saturation percentage), it can be predicted that prolonged acid precipitation will reduce the buffer capacity of soils and lead to soil acidification.

• Journal of Korean Society on Water Environment
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• v.25 no.1
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• pp.84-89
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• 2009

Our nation's water resources remain susceptible to contamination by phenolic agrichemicals. These compounds can be toxic to a variety of organisms including humans. Their disposal is restricted in many countries with strict limits for acceptable concentrations in drinking water. Enzyme-mediated in situ stabilization has been advocated as an approach for the treatment of phenolic compounds in soils and groundwater. This study reports the development of a new approach to quantify the activity of the HRP enzyme in aqueous systems. The method is based on the coupled processes of energy transfer and enhanced chemiluminescence using a luminol-$H_2O_2$-HRP system. In this study, the effects of solution pH, ionic strength and aqueous concentrations of HRP, $H_2O_2$ and enhancer were evaluated on the p-iodophenol-enhanced, HRP-catalyzed chemiluminescence reaction intensity in Tris-HCl buffer. All assay components were found to affect the maximum chemiluminescene intensity. The calibration curve for HRP showed the linear relationship with maximum light intensity.

• Journal of Marine Bioscience and Biotechnology
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• v.16 no.1
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• pp.36-44
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• 2024

This study attempted to improve the growth of the freshwater microalgae, Parachlorella kessleri, through the sequential optimization of culture conditions. This attempt aimed to enhance the microalgae's ability to fixate atmospheric CO₂. Culture temperature and light intensity appropriate for microalgal growth were scanned using a high-throughput photobioreactor system. The supplied air flow rate varied from 0.05 to 0.3 vvm, and its effect on the growth rate of P. kessleri was determined. Next, sodium phosphate buffer was added to the culture medium (BG11) to enhance CO₂ fixation by increasing the availability of CO₂(HCO₃^-) in the culture medium. The results indicated that optimal culture temperature and light intensity were 20℃-25℃ and 300 μE/m²/s, respectively. Growth rates of P. kessleri under various air flow rates highly depended on the increase of the culture's flow rate and pH which determines CO₂ availability. Adding sodium phosphate buffer to BG11 to maintain a constant neutral pH (7.0) improved microalgal growth compared to control conditions (BG11 without sodium phosphate). These results indicate that the CO₂ fixation rate in the air could be enhanced via the sequential optimization of microalgal culture conditions.

• Analytical Science and Technology
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• v.8 no.3
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• pp.359-364
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• 1995

Urinary dipeptidase(Udpase) was assayed by fluorometric analysis of NADH which was produced from an indicator enzyme, L-alanine dehydrogenase. The reaction mixture was consisted of a dipeptide(L-ala-L-ala), ${\beta}-NAD^+$, L-alanine dehydrogenase in 12.5 mM sodium carbonate buffer, pH 9.0, and urinary dipeptidase which initiated the reaction. The fluorescence intensity of NADH was measured as a function of time with the excitation wavelength at 340nm and emission at 460nm. Comparison of this fluorometric method with the conventional spectrophotometric method utilizing glycyldehydrophenylalanine(Gdp) as substrate provided the correlation coefficient of 0.996 and increased the sensitivity more than ten times.

• Journal of KIISE:Information Networking
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• v.29 no.2
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• pp.181-187
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• 2002

Connection admission control(CAC), which decides whether or not to accept a new call request, is one of the most Important preventive congestion control techniques in asynchronous transfer mode(ATM) networks. To develop a practical CAC scheme, first we propose a "Modified Cell Loss Probability MP${\nu}"$, which is based on "Virtual Cell Loss Probability P${\nu}"$, taking into account mean burst duration of input traffic source and buffer size in ATM networks. MP${\nu}"$ computes more accurate cell loss probability than P${\nu}"$ without increasing computational complexity, since P${\nu}"$ is formulated simply form the maximum and the average cell rate of input traffic. P${\nu}"$ is overestimated as compared to the real cell loss probability when the mean burst duration is relatively small to the buffer capacity. Then, we Propose a CAC scheme, based on "Modified Virtual Bandwidth(MVB)" method, which may individualize the cell loss probabilities in heterogeneous traffic environments. For the proposed approach, we define the interference intensity to identify interferences between heterogeneous traffic sources and use it as well as MP${\nu}"$ to compute MVB. Our approach is well suitable for ATM networks since it provides high bandwidth utilization and guarantees simple and real time CAC computation for heterogeneous traffic environments.heterogeneous traffic environments.

• Restorative Dentistry and Endodontics
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• v.25 no.2
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• pp.225-234
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• 2000

The purpose of this study was to investigate the distribution and fluorescene intensity of vasoactive intestinal polypeptide(VIP) immunoreactive cells in rat trigeminal ganglion after inferior alveolar nerve axotomy. The animals were divided into normal and two experimental groups. The experimental animals were sacrificed at 14th and 28th day after inferior alveolar nerve axotomy. The trigeminal ganglion was removed and immersed in the 4% paraformaldehyde-0.2% picric acid in 0.1M phosphate buffer. Serial frozon sections about $16{\mu}m$ in thickness were cut with a cryostat. The immunofluorescence staining was performed. The rabbit anti-VIP(1 : 8,000) was used as primary antibody and fluorescene isothiocynate(FITC)-conjugated anti-rabbit IgG(1 : 80) as secondary antibody. The slides were observed under confocal laser scanning microscope. Three-dimensional images were constructed from 9 serial images(each $1{\mu}m$ in thickness) made by automatic optical sectioning. Unprocessed optical sections were obtained and stored on a optical disk. Color picture were printed by a video copy processor. The results were as follows; 1. The appearance of VIP immunoreactive cells in the mandibular part of trigeminal ganglion was 8.79${\pm}$1.99% in normal group and 39.16${\pm}$5.62% in 14 days, 16.25${\pm}$2.39% in 28 days after inferior alveolar nerve axotomy groups. 2. The relative fluorescence intensity of VIP immunoreactive cell bodies in the mandibular part of trigeminal ganglion was 134.40${\pm}$10.39 in normal group and 192.88${\pm}$14.06 in 14 days, 143.10${\pm}$5.02 in 28 days after nerve axotomy groups. Therefore, the relative fluorescence intensity of 14 days after nerve axotomy group was 43.3% higher than intensity of normal group. 3. In optical single section analysis of VIP immunoreactive cell bodies, white cell bodies(moderate fluorescence intensity) were the most abundant in normal and 28 days after nerve axotomy groups. Whereas, in 14 days after nerve axotomy group, red cell bodies(high fluorescence intensity) were the most abundant. 4. In optical serial section analysis of VIP immunoreactive cell bodies, red cell bodies(high fluorescence intensity) were observed in a part of the 9 sections of normal and 24 days after nerve axotomy groups. Whereas, red cell bodies were observed in all of the 9 sections of 14 days after nerve axotomy group. 5. The results indicates that number and fluorescence intensity of VIP immunoreactive cells were increased in the mandibular part of trigeminal ganglion following inferior alveolar nerve axotomy.

• Journal of the Korean Ceramic Society
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• v.42 no.3 s.274
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• pp.178-181
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• 2005

Silicon oxynitride (SiON) layers deposited upon a $SiO_2/Si$ buffer layer placed upon silicon wafers have been obtained by using PECVD from $SiH_4,\;N_2O$, and $N_2$. It can be seen that the refractive index, measured by using a prism coupler, for the SiON films can be varied between 1.4480 and 1.4958 at a wavelength of 1552 nm by changing the process parameters. Optical planar waveguides with a thickness of $6{\mu}m$ and a refractive index contrast ($\Delta$n) of $0.36\% have been deposited. Also, etching experiments were performed using ICP dry etching equipment on thick SiON films grown onto Si substrates covered by a thick $SiO_2$ buffer layer. A polarization maintaining single-mode fiber was used for the input and a microscope objective for the output at $1.55{\mu}m$. As a result, a low index contrast SiON based waveguide is fabricated with easily adjustable refractive index of core layer. It illustrates that the output intensity mode is a waveguiding single-mode.

• Journal of the Korean Vacuum Society
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• v.7 no.4
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• pp.341-347
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• 1998

We analyzed photoreflectance (PR) characterization of the $Al_xGa_{1-x}As$ epilayer grown by molecular beam epitaxy (MBE) method. The band-gap energy $(E_0)$ satisfying low power Franx-Keldysh (LPFK) due to GaAs buffer layer is 1.415 eV, interface electricall field $(E_i)$ is 1.05$\times$$10^4$V/cm, carrier concentration (N) is $1.3{\times}10^{15}\textrm{cm}^{-3}$. In PR spectrum intensity analysis at 300 K the $A^*$ peak below $(E_0)$ signal is low and distorted because of residual impurity in sample growth. The trap characteristic time ${\tau}_i$ of GaAs buffer layer is about 0.086 ms, and two superposed PR signal near 1.42eV consist of the third derivative signal of chemically eteched GaAs substrate and Franz-Keldysh oscillation (FKO) signal due to GaAs buffer layer.