• Journal of Plant Biology
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• v.35 no.3
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• pp.247-252
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• 1992

The effect of iso-butanol on the electron transport rate of PS I and PS II was investigated in isolated spinach chloroplasts. In photosystem I, the rate of electron transport increased in the presence of 1 to 4% of isobutanol but decreased in 5 to 9% of iso-butanol. But in photosystem II, the rate of electron transport decreased when treated with 0.2 to 1% of iso-butanol. The inhibitory effect of isomers of butanol on PS II electron transport rate increased in the order of 2-butanol, tert-butanol, iso-butanol and I-butanol. This means that PS II activity was affected according to the arrangement of carbon atoms in butanol. The inhibitory effect of iso-butanol reduced when DPC was added in the solution. This means that iso-butanol affects PS II reduction side of thylakoid membrane primarily. The inhibitory effect of iso-butanol was reduced when $Mn^{2+},\;C^{2+}$ or BSA were added in the solution. PS II activity was restored when 1% iso-butanol treated chloroplast solution was diluted to twentyfold or when $Mn^{2+},\;C^{2+}$ or BSA was added to the diluted solution. However, the SDS-PAGE banding pattern of thylakoid membrane proteins was similar even in 2% iso-butanol treated chloroplasts and the control ones. Only in 5% iso-butanol treated chloroplasts these bands were very weak. These observations suggest that low concentrations of iso-butanol releases manganese and calcium ions from chloroplasts and inhibits the electron transport system. This inhibitory effect can be reversible in low concenterations but in high concentrations the inhibitory effect of iso-butanol become irreversible.rsible.

• Journal of Life Science
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• v.26 no.10
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• pp.1137-1152
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• 2016

Cells sense, respond, and adapt to a low oxygen environment called hypoxia, which is widely involved in a variety of human diseases. Adaptation to low oxygen concentrations includes gene expression changes by inducing hypoxic genes and reducing aerobic genes. Recently, the mitochondrial respiratory chain has been implicated in the control of these oxygen-regulated genes when cells experience hypoxia. In order to obtain an insight into an effect of the mitochondrial respiratory chain on cellular response to hyxpoxia, we here examined whole genome transcript signatures of respiration-proficient and respiration-deficient budding yeasts exposed to hypoxia using DNA microarrays. By comparing whole transcriptomes to hypoxia in respiration-proficient and respiration-deficient yeasts, we found that there are several classes of oxygen-regulated genes. Some of them require the mitochondrial respiratory chain for their expression under hypoxia while others do not. We found that the majority of hypoxic genes and aerobic genes need the mitochondrial respiratory chain for their expression under hypoxia. However, we also found that there are some hypoxic and aerobic genes whose expression under hypoxia is independent of the mitochondrial respiratory chain. These results indicate a key involvement of the mitochondrial respiratory chain in oxygen-regulated gene expression and multiple mechanisms for controlling oxygen-regulated gene expression. In addition, we provided gene ontology analyses and computational promoter analyses for hypoxic genes identified in the study. Together with differentially regulated genes under hypoxia, these post-analysis data will be useful resources for understanding the biology of response to hypoxia.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.243-244
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• 2013

Over the past 15 years, several groups have incorporated radio-frequency quadrupole (RFQ) based instruments before the accelerator in accelerator mass spectrometry (AMS) systems for ion-gas interactions at low kinetic energy (＜40 eV). Most AMS systems arebased on a tandem accelerator, which requires negative ions at injection. Typically, AMS sensitivity abundance ratios for radioactive-to-stable isotope are limited to Xr/Xs ＞10^-15, and the range of isotopes that can be analyzed is limited because of theneed to produce rather large negative ion beams and the presence of atomic isobaric interferences after stripping. The potential of using low-kinetic energy ion-gas interactions for isobar suppression before the accelerator has been demonstrated for several negative ion isobar systems with a prototype RFQ system incorporated into the AMS system at IsoTrace Laboratory, Canada (Ontario, Toronto). Requisite for any such RFQ system applied to very rare isotope analysis is large transmission of the analyte ion. This requires proper phase-space matching between the RFQ acceptance and the ion beam phase space (e.g. 35 keV, ${\varphi}3mm$, +-35 mrad), and the ability to control the average ion energy during interactions with the gas. A segmented RFQ instrument is currently being designed at Korea Institute for Science and Technology (한국과학기술연구원, KIST). It will consist of: a) an initial static voltage electrode deceleration region, to lower the ion energy from 35 keV down to ＜40 eV at injection into the first RFQ segment; b) the segmented quadrupole ion-gas interaction region; c) a static voltage electrode re-acceleration region for ion injection into a tandem accelerator. Design considerations and modeling will be discussed. This system should greatly lower the detection limits of the 6 MV AMS system currently being commissioned at KIST. As an example, current detection sensitivity of 41Ca/Ca is limited to the order of 10^-15 while the 41Ca/Ca abundance in modern samples is typically 41Ca/Ca~10^-14 - 10^-15. The major atomic isobaric interference in AMS is 41K. Proof-of-principal work at IsoTrace Lab. has demonstrated that a properly designed system can achieve a relative suppression of KF3-/41CaF3- ＞4 orders of magnitude while maintaining very high transmission of the 41CaF3- ion. This would lower the 41Ca detection limits of the KIST AMS system to at least 41Ca/Ca~10^-19. As Ca is found in bones and shells, this would potentially allow direct dating of valuable anthropological archives and archives relevant to our understanding of the most pronounced climate change events over the past million years that cannot be directly dated with the presently accessible isotopes.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.11
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• pp.58-63
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• 2013

This paper presents a transceiver design for DisplayPort interface using an optical channel. By converting the electronic channel to the optical channel, the DisplayPort's main channel can provide a high-speed data transmission for long distance. The design converting the electronic channel to the optical channel in the main channel and AUX channel of the DisplayPort is presented in this paper. Futhermore, the HPD signal transmission by using AUX channel is proposed. In order to minimize power consumption, this paper also proposed a method of controlling the TX block in the main link. The proposed system is designed by a FPGA and an optical module. The FPGA used 651 ALUT(adaptive look-up table)s, 511 resisters and 324 block memory bits. The maximum operating rate of the FPGA is 250MHz. With the proposed power control scheme, 740mW of power dissipation reduction can be achieved at the main link optical TX module.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.37 no.4
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• pp.669-680
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• 2017

This study evaluated the consistency of the standard flow to forecast low-flow based on various drought indices. The data used in this study were streamflow data at the Gurye2 station located in the Seomjin River and the Angang station located in the Hyeongsan River, as well as rainfall data of nearby weather stations (Namwon and Pohang). Using streamflow data, the streamflow accumulation drought index (SADI) was developed in this study to represent the hydrological drought condition. For SADI calculations, the threshold of drought was determined by a Change-Point analysis of the flow pattern and a reduction factor was estimated based on the kernel density function. Standardized runoff index (SRI) and standardized precipitation index (SPI) were also calculated to compared with the SADI. SRI and SPI were calculated for the 30-, 90-, 180-, and 270-day period and then an ROC curve analysis was performed to determine the appropriate time-period which has the highest consistency with the standard flow. The result of ROC curve analysis indicated that for the Seomjin River-Gurye2 station SADI_C3, SRI30, SADI_C1, SADI_C2, and SPI90 were confirmed in oder of having high consistency with standard flow under the attention stage and for the Hyeongsan River-Angang station, SADI_C3, SADI_C1, SPI270, SRI30, and SADI_C2 have order of high consistency with standard flow under the attention stage.

• Journal of the Economic Geographical Society of Korea
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• v.3 no.2
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• pp.43-61
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• 2000

This study investigate the spatial characteristics and corporate networks of foreign business service firms in Korea. Specifically intrafirm and extrafirm organization of foreign firms are addressed utilizing the corporate network perspective. For this purpose, this study conducted questionnaire and interview surveys for the foreign firms. Parent-subsidiary relationships are focused on the mechanisms by which Transnational Corporations (TNCs) headquarters control and coordinate their foreign affiliates and subsidiaries in order to achieve investment purpose in Korea (overseas market expansion). But extrafirm networks of foreign business services firms in Korea do not appear to play an important role in regional development to date. A low proportion of foreign firms is engaged in academics-industry linkages, and a low number o( foreign firms is formally linked with government organizations, research institutes, and trade associations. To conclude, Foreign direct investment firms in business services in Korea are characteristics by globalized intrafirm networks and localized interfirm and extrafirm networks. It is understood that regional development can be vitalized when Korean local firms have close relationships with technologically advanced foreign firms in tacit knowledge capacity. Foreign firms are able to play an important role in the development of business services in Korea. This study suggests that regional foreign direct investment policy should be targeted towards the corporate networking with foreign firms and domestic firms and incrementation of the potential of foreign firms as a knowledge-intensive industry.

• Korean Chemical Engineering Research
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• v.49 no.6
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• pp.857-864
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• 2011

Oxy-fuel combustion with many advantages such as high combustion efficiency, low flue gas flow rate and low NOx emission has emerged as a promising CCS technology for coal combustion facilities. In this study, the effects of the direct sulfation reaction on $SO_2$ removal efficiency were evaluated in a drop tube furnace under typical oxy-fuel combustion conditions represented by high concentrations of $CO_2$ and $SO_2$ formed by gas recirculation to control furnace combustion temperature. The effects of the operating parameters including the reaction temperature, $CO_2$ concentration, $SO_2$ concentration, Ca/S ratio and humidity on $SO_2$ removal efficiency were investigated experimentally. $SO_2$ removal efficiency increased with reaction temperature up to 1,200 due to promoted calcination of limestone reagent particles. And $SO_2$ removal efficiency increased with $SO_2$ concentrations and the humidity of the bulk gas. The increase of $SO_2$ removal efficiency with $CO_2$ concentrations showed that $SO_2$ removal by limestone was mainly done by the direct sulfation reaction under oxy-fuel combustion conditions. From the impact assessment of operation parameters, it was shown that these parameters have an effects on the desulfurization reaction by the order of the Ca/S ratio > residence time > $O_2$ concentration > reaction temperature > $SO_2$ concentration > $CO_2$ concentration > water vapor. The semi-empirical model equation for to evaluate the effect of the operating parameters on the performance of in-furnace desulfurization for oxy-fuel combustion was established.

• Journal of the Korean Magnetics Society
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• v.21 no.2
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• pp.77-82
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• 2011

The use of soft magnetic materials have been increasing in the various industrial fields according to the increasing demand for high performance, automatic, miniaturing equipments in the recent our life. In this study, we investigated the effect of factors on the core loss and magnetic properties of electrical steel and soft magnetic composites. Furthermore, we reviewed the major efforts to reduce the core loss and improve the soft magnetic properties in the two main soft magnetic materials. Domain purification which results from reduced density of defects in cleaner electrical steels is combined with large grains to reduce hysteresis loss. The reduced thickness and the high electrical conductivity reduce the eddy current component of loss. Furthermore, the coating applied to the surface of electrical steel and texture control lead to improve high permeability and low core loss. There is an increasing interest in soft magnetic composite materials because of the demand for miniaturization of cores for power electronic applications. The SMC materials have a broad range of potential applications due to the possibility of true 3-D electromagnetic design and higher frequency operation. Grain size, sintering temperature, and the degree of porosity need to be carefully controlled in order to optimize structure-sensitive properties such as maximum permeability and low coercive force. The insulating coating on the powder particles in SMCs eliminates particle-to-particle eddy current paths hence minimizing eddy current losses, but it reduces the permeability and to a small extent the saturation magnetization. The combination of new chemical composition with optimum powder manufacturing processes will be able to result in improving the magnetic properties in soft magnetic composite materials, too.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.11
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• pp.7990-8000
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• 2015

Plant factories are plant cultivation systems which produce farm products uniformly under the controlled environmental condition regardless of seasons and places. Thermal flow in the plant factory is an important parameter in cultivating plants. In this research, we study thermal flow characteristics for a hybrid plant factory with multi-layer cultivation shelves using computer simulation techniques. In order to obtain numerical solutions for thermal flow characteristics, a finite volume method was applied. We consider a low-Reynolds-number ${\kappa}-{\epsilon}$ turbulence model, incompressible viscous flows, and pressure boundary conditions for numerical simulation. Commercial software Solid Works Flow Simulation is then used to investigate characteristics of thermal flows in the plant factory applying several different inflow air velocities and arrangements of cultivation shelves. From numerical analysis results, we found that temperatures in cultivation shelves were uniformly distributed for Case 3 when the inflow air velocity was 1.6 m/s by using a blower in the plant factory. However in Case 1 lower temperature distributions were observed in test beds, TB2 and TB3, which indicated that additional temperature control efforts would be required. Average shelf temperature increased by $3^{\circ}C$ using artificial light source (DYLED47) with 50% blue and 50% red LED ratios. Korea Academia-Industrial cooperation Society.

• Korean Journal of Remote Sensing
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• v.21 no.4
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• pp.287-302
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• 2005

Digital Elevation Models (DEMs) were generated by ERS-l/2 and JERS-1 SAR interferometry in Daejon area, Korea. The quality of the DEM's was evaluated by the Ground Control Points (GCPs) in city area where GCPs were determined by GPS surveys, while in the mountain area with no GCPs, a 1:25,000 digital map was used. In order to minimize errors due to the inaccurate satellite orbit information and the phase unwrapping procedure, a Differential InSAR (DInSAR) was implemented in addition to the traditional InSAR analysis for DEM generation. In addition, DEMs from GTOPO30, SRTM-3, and 1:25,000 digital map were used for assessment the resolution of the DEM generated from DInSAR. 5-6 meters of elevation errors were found in the flat area regardless of the usage and the resolution of DEM, as a result of InSAR analyzing with a pair of ERS tandem and 6 pairs of JERS-1 interferograms. In the mountain area, however, DInSAR with DEMs from SRTM-3 and the digital map was found to be very effective to reduce errors due to phase unwrapping procedure. Also errors due to low signal-to-noise ratio of radar images and atmospheric effect were attenuated in the DEMs generated from the stacking of 6 pairs of JERS-1. SAR interferometry with multiple pairs of SAR interferogram with low resolution DEM can be effectively used to enhance the resolution of DEM in terms of data processing time and cost.