• 전자공학회논문지 IE
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• v.43 no.1
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• pp.39-45
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• 2006

The increment of user at mobile communication system requires the need of increased system capacity. To increase the system capacity can be realized by decreasing the size of cell. But, this method causes various problems. Therefore, it be used the hierarchical cellular system with macrocell and microcell for a efficient working. The users feel more inconvenience about the drop of connected call than the block of new call. Therefore, it is to be desired that the dropping rate of handoff call is lowered. At this paper, we use non reversible hierarchical scheme and fixed channel assignment scheme at the hierarchical cellular system with macrocell and microcell for the call process strategy. We analyze the system performance in accordance with the number of guard channel for handoff.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.110-110
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• 2017

Stomata are the main gateways for water and air transport between leaves and the environment. Inward-rectifying potassium channels regulate photo-induced stomatal opening. Rice contains three inward rectifying shaker-like potassium channel proteins, OsKAT1, OsKAT2 and OsKAT3. Among these, only OsKAT2 is specifically expressed in guard cells. Here, we investigated the functions of OsKAT2 in stomatal regulation using three dominant negative mutant proteins, OsKAT2(T235R), OsKAT2(T285A) and OsKAT2(T285D), which are altered in amino acids in the channel pore and at a phosphorylation site. Yeast complementation and patch clamp assays showed that all three mutant proteins lost channel activity. However, among plants overexpressing these mutant proteins, only plants overexpressing OsKAT2(T235R) showed significantly less water loss than the control. Moreover, overexpression of this mutant protein led to delayed photo-induced stomatal opening and increased drought tolerance. Our results indicate that OsKAT2 is an inward-rectifying shaker-like potassium channel that mainly functions in stomatal opening. Interestingly, overexpression of OsKAT2(T235R) did not cause serious defects in growth or yield in rice, suggesting that OsKAT2 is a potential target for engineering plants with improved drought tolerance without yield penalty.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.41 no.3
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• pp.228-231
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• 2008

Two methods for separating dinoflagellate cysts from marine sediments were compared: panning and sodium polytungstate (SPT). After pretreatment with the SPT solution, Protoperidinium species had a high germination rate and cell growth rate. The germinated cells grew continuously, even in a low nutrient environment. Alexandrium cysts did not germinate, because their germination is usually active in winter. Using SPT solution, the separation process was easier, quicker, and caused much less eye fatigue than the panning method. Therefore, SPT solution offers a convenient way of pretreating dinoflagellate cysts for separation and analysis.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.14 no.8
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• pp.622-628
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• 2001

We developed 1- and 2-dimensional fluid model for the analysis of a capacitively coupled Ar RF(Radio Frequency) glow discharge. This discharge is in pure Ar gas at the pressure 100[mTorr], frequency 13.56[MHz] and voltage amplitude 120[V}. This model is based on the equations of continuity and electron energy conservation coupled with Poison equation. 2-dimensional model is simulated on the condition of GEC(Gaseous Electronic Conference cell). The geometry of the discharge chamber and the electrodes used in the model is cylindrically simmetric; tow cylinders for the electrodes are surrounded by the grounded chamber. It is shown that 1-dimensional model is very useful on the understanding of RF glow discharge property and of the movement of charged particles. 2-dimensional model predicts off-axis maximum structure as in the experiments and has the results in qualitatively and quantitatively good agreement with the experiments. Effects of dc self-bias voltage, guard ring and reactor geometry is discussed.

• Proceedings of the KIPE Conference
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• 2005.07a
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• pp.730-733
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• 2005

본 연구는 신재생에너지의 하나인 태양광 발진의 소형 발전의 활용분야의 하나로 기존 정원 보안등의 전력원을 상용전원에서 태양전지로 변환하여 직용, 실증화한 연구 결과로서 태양전기 전원의 특성과 배터리의 노화, 반사갓의 차이점을 실증화 시험을 통하여 분석하였으며 각각의 실험결과들은 웹을 통하여 원격 모니터링이 가능하도록 시스템을 구성하였다.

• Journal of the Korean Institute of Gas
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• v.27 no.1
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• pp.13-22
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• 2023

As an alternative to environmental pollution generated from fossil fuels currently in use, research is being actively conducted to use hydrogen that does not cause air pollution. As fire and explosion accidents caused by hydrogen leakage have occurred until recently, research on safety is needed to commercialize hydrogen on ships, which are special environments. In this study, a seasonal alternative scenario for each season and the worst scenario were assumed in the event of a leakage accident while a hydrogen fuel cell propulsion ship equipped with a hydrogen storage tank was navigating at JangSaengPo port in Ulsan. In order to consider environmental variables, the damage impact range was derived through ALOHA and probit analysis based on the annual average weather data for 2021 by the Korea Meteorological Administration and on geographic information data from the National Statistical Office. Radiation showed a wider damage range than that of Overpressure and Flame in both the alternative and worst-case scenarios, and as a result of probit analysis, a fatality rate of 99% was confirmed in all areas.

• BMB Reports
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• v.49 no.10
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• pp.554-559
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• 2016

Mycobacterium abscessus, a member of the group of non-tuberculous mycobacteria, has been identified as an emerging pulmonary pathogen in humans. However, little is known about the protective immune response of antigen-presenting cells, such as dendritic cells (DCs), which guard against M. abscessus infection. The M. abscessus gene MAB1843 encodes ᴅ-alanyl-ᴅ-alanine dipeptidase, which catalyzes the hydrolysis of ᴅ-alanyl-ᴅ-alanine dipeptide. We investigated whether MAB1843 is able to interact with DCs to enhance the effectiveness of the host's immune response. MAB1843 was found to induce DC maturation via toll-like receptor 4 and its downstream signaling pathways, such as the mitogen-activated protein kinase and nuclear factor kappa B pathways. In addition, MAB1843-treated DCs stimulated the proliferation of T cells and promoted Th1 polarization. Our results indicate that MAB1843 could potentially regulate the immune response to M. abscessus, making it important in the development of an effective vaccine against this mycobacterium.

• Journal of Plant Biotechnology
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• v.38 no.1
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• pp.1-8
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• 2011

Recently the increasing of vinyl and green houses and development of reclaimed land including Saemangeum induced the need for breeding salt-tolerant crops which can survive and grow in high salinity soil. So we try to develop salt-tolerant transgenic chrysanthemum (Dendranthema grandiflorum.) lines by using anti-porter gene TANHX and HVNHX. Through marker selection and plant regeneration step, we could get 284 putative transgenic chrysanthemum lines. On selected putative transgenic plants, 40 candidates were used for genetic analysis and 30 lines could be made up of target size band on PCR, so about 75% of marker selected lines were decided as real transgenic lines. Selected 284 transgenic lines were also used for salt-tolerance test as a range of NaCl 0.2 ~ 1.2% (300 mM). As a result of salt-tolerance test, 15 selected transgenic lines could live and grow on the continuous supply of 0.8% (200 mM) NaCl solution and another 7 lines were could survive under 1.2% (300 mM) NaCl solution. This salt-tolerant transgenic lines under salt stress also lead a cell alternation especially a guard cell. A stressed guard cell be swelled and grow larger in proportion to NaCl concentration. TTC test for cell viability on transgenic chrysanthemum lines pointed out that more strong salt-tolerant lines can be live more than another under same salt stress. The numerical value of strong salt-tolerant 7 transgenic lines were 0.206 ~ 0.331 under 1.2% NaCl stress, and then it's value is more larger than middle salinity lines' 0.114 ~ 0.193 and non-transgenic's 0.046. And the proline contents as indicated stress compound also pointed out that HVNHX introduced salt-tolerant transgenic lines were less stressed than other under same salt stress. The contents of strong salt-tolerant transgenic lines were 2.255 ~ 2.638 mg/kg and it is much higher than that of middle salinity lines' 1.496 ~ 2.125.

• Journal of Plant Biology
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• v.16 no.1_2
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• pp.17-22
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• 1973

The experiments were conducted to examine the injuries of $SO_2$, $NH_3$, and $SO_2$ and NH3 mixed gas to the germination and the growth of plants. Six kinds of plants were used as the material. These plants seeds were treated with the gases for five days. Rate of the germination and the growth in height of varying plants were different according to the components of the gases. The critical concentration of the gases for both the germination and the growth were in 5ppm of $SO_2$, 50ppm of $NH_3$, and 50ppm $SO_2$ and 50ppm $NH_3$ mixed gases. When a low concentration of $SO_2$ was treated together with NH3, especially it was reduced to 60 percent of the damage in the germination and the growth. In the treatemnt with $SO_2$, the germination of the seeds which soaked in water for 24 hours reduced the injuries more 40 percent than those which for one hour. It was observed that the seeds with thick coasts or with originally intact coats were suffered but little damaged by the gases, and the external symptoms of an injury were shown, at first, in water pore, and then, in guard cell on the leaves.

• Restorative Dentistry and Endodontics
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• v.42 no.1
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• pp.39-47
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• 2017

Objectives: Although the coating of surface sealants to dental composite resin may potentially reduce bacterial adhesion, there seems to be little information regarding this issue. This preliminary in vitro study investigated the adhesion of Streptococcus mutans (S. mutans) on the dental composite resins coated with three commercial surface sealants. Materials and Methods: Composite resin (Filtek Z250) discs (8 mm in diameter, 1 mm in thickness) were fabricated in a mold covered with a Mylar strip (control). In group PoGo, the surfaces were polished with PoGo. In groups PS, OG, and FP, the surfaces polished with PoGo were coated with the corresponding surface sealants (PermaSeal, PS; OptiGuard, OG; Fortify Plus, FP). The surfaces of the materials and S. mutans cells were characterized by various methods. S. mutans adhesion to the surfaces was quantitatively evaluated using flow cytometry (n = 9). Results: Group OG achieved the lowest water contact angle among all groups tested (p < 0.001). The cell surface of S. mutans tested showed hydrophobic characteristics. Group PoGo exhibited the greatest bacterial adhesion among all groups tested (p < 0.001). The sealant-coated groups showed statistically similar (groups PS and FP, p > 0.05) or significantly lower (group OG, p < 0.001) bacterial adhesion when compared with the control group. Conclusions: The application of the surface sealants significantly reduced S. mutans adhesion to the composite resin polished with the PoGo.