• Bulletin of the Korean Chemical Society
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• v.32 no.2
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• pp.681-686
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• 2011

SPLITT Fractionation (SF) provides separation of sample into two subpopulations. Separation into more than two subpopulations requires repeated SF operations. In this study, two Gravitation SF (GSF) channels were connected in a series (Tandem GSF) to obtain a separation into three subpopulations and to improve the fractionation efficiency (FE) of the fraction-b in the full-feed depletion (FFD) mode. In a single channel FFD-GSF operation, the fraction-a contained mostly the beads smaller than the cutoff diameter ($d_c$), while the fraction-b contained beads smaller than $d_c$ as well as those larger than dc, as expected. The measured FE's of the fraction-b are much lower than those of the fraction-a in all cases. The FE's of the fraction-a are higher than 84% with the average of about 91%, while those of the fraction-b are lower than 60% with the average of about 43%. No particular trends were found between FE and $d_c$, indicating the performance of FFD-GSF does not change with $d_c$ in the range where tested. Also no clear trends were observed between the FE and the sample-feeding flow rate, indicating higher sample-feeding rate can be used to increase the sample throughput without losing resolution. When two GSF channels were connected so that the flow stream emerging from the outlet-b of the channel-1 is fed directly into the channel-2, all three FE's measured for the fraction-1a were high with the average value of 99%, indicating it contains almost purely the beads smaller than $d_c$. The FE's measured for the fraction-2a are still good with the average value of 92%. The FE's measured for the fraction-2b are 64% in average, which is about 20% improvement from those obtained in a single channel FFD-GSF at the same conditions.

• The Korean Journal of Pesticide Science
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• v.2 no.3
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• pp.1-20
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• 1998

Chlorsulfuron, one of sulfonylurea herbicides acts through inhibition of acetolactate syuthase (EC 4.1.3.18; ALS, also known as acetohydroxyacid synthase) in the branched-chain amino acid biosynthesis process. After chlorsulfuron-ALS interaction, many physiological and metabolic disruptions occur in plants. However, it is not clear how this chlorsulfuron-ALS interaction affects those physiological and metabolic processes and how this interaction leads subsequently to plant death. Several researchers suggested that the death of chlorsulfuron-treated plants might be due to a shortage of the branched-chain amino acids, an accumulation of toxic metabolites, and/or a depletion of photoassimilates. It remains as a mystery presently, however, if such changes result in the plant death. In this review, we discussed how the chlorsulfuran-ALS interaction leads to physiological and metabolic disruptions in plants.

• Proceedings of the Materials Research Society of Korea Conference
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• 2009.11a
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• pp.26.1-26.1
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• 2009

A simple route of external mechanical force is presented for enhancing the electrical properties of polymer nanocomposite consisted of nanowires. By dispersing ZnO nanowires in polymer solution and drop casting on substrates, nanocomposite transistors containing ZnO nanowires are successfully fabricated. Even though the ZnO nanowires density is properly controlled for device fabrication, as-cast device doesn't show any detectable currents, because nanowires are separated far from each other with the insulating polymer matrix intervening between them. Compared to the device pressed at 300 kPa, the device pressed at 600 kPa currents increased by 50times showing the linear behavior against drain voltage and exhibits promising electrical properties, which operates in the depletion mode with higher mobility and on-current. Such an improved device performance would be realized by the contacts improvement and the increase of the number of electrical path induced by external force. This approach provides a viable solution for serious contact resistance problem of nanocomposite materials and promises for future manufacturing of high-performance devices.

• Proceedings of the Materials Research Society of Korea Conference
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• 2009.11a
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• pp.26.2-26.2
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• 2009

A simple route of externalmechanical force is presented for enhancing the electrical properties ofpolymer nanocomposite consisted of nanowires. By dispersing ZnO nanowires inpolymer solution and drop casting on substrates, nanocomposite transistorscontaining ZnO nanowires are successfully fabricated. Even though the ZnOnanowires density is properly controlled for device fabrication, as-cast devicedoesn't show any detectablecurrents, because nanowires are separated far from each other with theinsulating polymer matrix intervening between them. Compared to the devicepressed at 300 kPa, the device pressed at 600 kPa currents increased by 50times showing the linear behavior against drain voltage and exhibits promisingelectrical properties, which operates in the depletion mode with highermobility and on-current. Such an improved device performance would be realizedby the contacts improvement and the increase of the number of electrical pathinduced by external force. This approach provides a viable solution for seriouscontact resistance problem of nanocomposite materials and promises for futuremanufacturing of high-performance devices.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.49 no.1
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• pp.1-7
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• 2012

We have developed a new gate driver circuit for liquid crystal displays using oxide thin-film transistors (TFTs). In the new gate driver, negative gate bias is applied to turn off the oxide TFTs because the oxide TFT occasionally has negative threshold voltage (VT). In addition, we employed three parallel pull-down TFTs that are turned on in turns to enhance the stability. SPICE simulation showed that the proposed circuit worked successfully covering the VT range of -3 V ~ +6 V And fabrication results confirmed stable operation of the new circuit using oxide TFTs.

• JSTS:Journal of Semiconductor Technology and Science
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• v.6 no.2
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• pp.101-105
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• 2006

Nanoscale floating-gate characteristic of colloidal Au nanoparticles electrostatically assembled on the oxidized surface of Si nanowires have been investigated. The Si nanowire split-gate transistor structure was fabricated by electron beam lithography and subsequent reactive ion etching. Colloidal Au nanoparticles with ${\sim}5$ nm diameters were selectively deposited onto the Si nanowire surface by 2 min electrophoresis. It was found that electric fields applied to the self-aligned split side gates allowed charge to be transferred on the Au nanoparticles. It was observed that the depletion mode cutoff voltage, induced by the self-aligned side gates, was shifted by more than 1 V after Au nanoparticle electrophoresis. This may be due to the semi-one dimensional nature of the narrow Si nanowire transport channel, having much enhanced sensitivity to charges on the surface.

• BMB Reports
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• v.50 no.1
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• pp.31-36
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• 2017

High-dose caffeine uptake is a developmental stressor and causes food-avoidance behavior (aversion phenotype) in C. elegans, but its mode of action is largely unknown. In this study, we investigated the molecular basis of the caffeine-induced aversion behavior in C. elegans. We found that aversion phenotype induced by 30 mM caffeine was mediated by JNK/MAPK pathway, serotonergic and dopaminergic neuroendocrine signals. In this process, the dopaminergic signaling appears to be the major pathway because the reduced aversion behavior in cat-2 mutants and mutants of JNK/MAPK pathway genes was significantly recovered by pretreatment with dopamine. RNAi depletion of hsp-16.2, a cytosolic chaperone, and cyp-35A family reduced the aversion phenotype, which was further reduced in cat-2 mutants, suggesting that dopaminergic signal is indeed dominantly required for the caffeine-induced food aversion. Our findings suggest that aversion behavior is a defense mechanism for worms to survive under the high-dose caffeine conditions.

• Journal of Power System Engineering
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• v.19 no.6
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• pp.39-46
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• 2015

With rising fuel costs and the depletion of fossil fuels, electric vehicles of high efficiency has been increasing interest. although high-performance battery continually is developing, Electric vehicles is not satisfied with the characteristics of the environment. In this study, By using the current fuel economy testing methods(5-cycle test), until the fully discharged battery electric vehicles is evaluated for a variety of environmental and operating conditions. As a result, Electric vehicles showed a low energy consumption efficiency in low temperature and rapid acceleration, deceleration in the operating environment compared with normal temperature.

• Molecules and Cells
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• v.39 no.2
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• pp.163-168
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• 2016

Caffeine has both positive and negative effects on physiological functions in a dose-dependent manner. C. elegans has been used as an animal model to investigate the effects of caffeine on development. Caffeine treatment at a high dose (30 mM) showed detrimental effects and caused early larval arrest. We performed a comparative proteomic analysis to investigate the mode of action of high-dose caffeine treatment in C. elegans and found that the stress response proteins, heat shock protein (HSP)-4 (endoplasmic reticulum [ER] chaperone), HSP-6 (mitochondrial chaperone), and HSP-16 (cytosolic chaperone), were induced and their expression was regulated at the transcriptional level. These findings suggest that high-dose caffeine intake causes a strong stress response and activates all three stress-response pathways in the worms, including the ER-, mitochondrial-, and cytosolic pathways. RNA interference of each hsp gene or in triple combination retarded growth. In addition, caffeine treatment stimulated a food-avoidance behavior (aversion phenotype), which was enhanced by RNAi depletion of the hsp-4 gene. Therefore, up-regulation of hsp genes after caffeine treatment appeared to be the major responses to alleviate stress and protect against developmental arrest.

• Journal of Power Electronics
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• v.13 no.3
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• pp.390-399
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• 2013

As a result of the depletion of fossil fuels and environmental contamination, it has become important to use renewable energy. For the stable utilization of renewable energy sources, energy storage devices must be used. In addition, renewable and distributed power sources with energy storage devices must operate stably under grid-connected mode. This paper proposed dynamic response modeling for renewable power generation systems including a charger/discharger with an energy storage device in order to derive a method to guarantee stable operation while fully utilizing the energy from the energy storage device. In this paper, the principle operation and design guidelines of the proposed scheme are presented, along with a performance analysis and simulation results using MATLAB and PSIM. Finally, a hardware prototype of a 1kW power conditioning system with an energy storage device has been implemented for experimental verification of the proposed converter system.