• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.1
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• pp.132-140
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• 2008

Power system of Jeju is interconnected to the mainland using HVDC and that is also interconnected two wind farms. Control of Jeju power system will be difficult if HVDC is disconnected or HVDC is overhauled under large scale wind farms interconnected. We measured and analysed the power quality of two substation and two wind farms to assess that wind farms and HVDC overhaul have an effect on Jeju system or not during the HVDC overhaul. We found that the frequency of Jeju system is very unstable and the voltage distortion excess the limitation. Harmonic currents of wind farms flew into Jeju system in proportion to the power of wind turbine. And the voltage of nearby distribution line was distorted by power of wind turbine when the amount is more that 3,000[kW].

• Journal of Electrical Engineering and Technology
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• v.3 no.3
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• pp.391-400
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• 2008

Multi-pulse topology of converters using elementary six-pulse GTO - VSC (gate turn off based voltage source converter) operated under fundamental frequency switching (FFS) control is widely adopted in high power rating static synchronous compensators (STATCOM). Practically, a 48-pulse ($6{\times}8$ pulse) configuration is used with the phase angle control algorithm employing proportional and integral (PI) control methodology. These kinds of controllers, for example the ${\pm}80MVAR$ compensator at Inuyama switching station, KEPCO, Japan, employs two stages of magnetics viz. intermediate transformers (as many as VSCs) and a main coupling transformer to minimize harmonics distortion in the line and to achieve a desired operational efficiency. The magnetic circuit needs altogether nine transformers of which eight are phase shifting transformers (PST) used in the intermediate stage, each rating equal to or more than one eighth of the compensator rating, and the other one is the main coupling transformer having a power rating equal to that of the compensator. In this paper, a two-level 48-pulse ${\pm}100MVAR$ STATCOM is proposed where eight, six-pulse GTO-VSC are employed and magnetics is simplified to single-stage using four transformers of which three are PSTs and the other is a normal transformer. Thus, it reduces the magnetics to half of the value needed in the commercially available compensator. By adopting the simple PI-controllers, the model is simulated in a MATLAB environment by SimPowerSystems toolbox for voltage regulation in the transmission system. The simulation results show that the THD levels in line voltage and current are well below the limiting values specified in the IEEE Std 519-1992 for harmonic control in electrical power systems. The controller performance is observed reasonably well during capacitive and inductive modes of operation.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.49 no.1
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• pp.61-68
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• 2004

A reproducible transformation system via optimized regeneration media for Korean rice cultivars was established using Agrobacterium tumefeciens LBA4404 (pSBM-PPGN; gusA and bar). Although japonica rice genotypes were easier to produce transgenic plants compared to Tongil type cultivars, transformation efficiencies were not always correlated with regeneration efficiencies of non-transgenic callus on the control medium. Regeneration efficiencies of Donganbyeo, Ilmibyeo, and Manchubyeo were over 50% in non-transgenic control, however, transformation efficiencies were significantly low when only sucrose was added to the media as a carbon source. However, the medium, MSRK5SS-Pr (or MSRK5SM-Pr), that contains $5\textrm{mgL}^{-1}$ kinetin, $0.5\textrm{mgL}^{-1}$ NAA, 2 % sucrose (or maltose), 3% sorbitol, and $500\textrm{mgL}^{-1}$ proline, was the most efficient not only for regeneration of non-transgenic callus but also for regeneration of transgenic callus in the presence of L-phosphinotricin (PPT). Average transformation efficiencies of 16 Korean rice cultivars were significantly enhanced by using the optimized medium from 1.5% to 5.8% in independent callus lines and from 2.9% to 19.4% in tromsgenic plants obained. Approximately 98.9% (876 out of 885) transgenic plants obtained on optimized media showed basta resistance. Stable integration, inheritance and expression of gusA and bar genes were continued by GUS assay and PCR and Southern analysis of the bar gene. With Pst1 digestion of genomic DNA of transgenic plants, one to five copies of T-DNA segment were observed; however, 76% (19 out of 25 transgenic plants) has low copy number of T-DNA. The transformants obtained from one callus line showed the same copy numbers with the same fractionized band patterns.

• Horticultural Science & Technology
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• v.17 no.6
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• pp.770-772
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• 1999

This study was conducted to provide a basic system to develop a molecular marker for plant cultivar protection using a recombinant DNA technology. Using Nicotiana tabacum L. plants, the potentiality in the utilization of the developed marker was examined. After homology test with several plant genomes, mouse adenosine deaminase (ADA) gene was selected as DNA source of a molecular marker for cultivar protection. As a result of the digestion of ADA gene with BamHI and Pst I, six DNA fragments were obtained, and 513 bp DNA fragment among them was selected as a possible DNA marker for cultivar protection. Selected 513 bp DNA fragment was efficiently inserted into pBI101 plasmid vector for plant transformation by using phagemid vector pBluescript II SK (+/-) as an intermediate vector. The recombinant pBI101, carrying 513 bp DNA fragment, possible markers for cultivar protection, was transformed into A. tumefaciens LBA4404. Nicotiana tabacum was transformed with A. tumefaciens LBA4404 having the recombinant pBI101 and was confirmed the transfer of 513 bp DNA fragment, a possible molecular marker for cultivar protection.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2002.05a
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• pp.371-377
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• 2002

근래 정보 시스템의 흐름은 생산 분야의 관리뿐만 아니라, 고객과의 관계를 중시하는 CRM(Costumer Relation Management)과 공급업체와의 협업 관계를 유지하는 eProcurement시스템에 초점을 맞추고 있다. 즉, 기존에는 단위 생산 시스템의 관리에 중점을 두었지만 최근에는 그 외부 요소들에 대한 관리의 중요성을 인식하게 되었고 이를 통징하여 공급망 관리(SCM Supply Chain Management)라고 한다. 본 논문에서는 공급망 관리에서 필요한 생산 계획수립 문제에 대해서 살펴본다. 특히 고객과의 관계에서 중요한 기능인 납기 회답을 지원하는 생산 계획 수립의 실행 주기에 대해서 살펴본다. 첫째, 단위 생산 시스템에서 사용하는 작업지시(Work Order)와 구매 지시(Purchase Order)를 생성하는 정규계획 모델에 대해서 설명한다. 정규계획 모델에서 필요로 하는 정적 정보와 동적 정보의 수집 및 계획의 실행을 담당하는 ERP 시스템과의 관계에 대해서 정의하고 정규계획 모델의 운영 주기를 정의한다. 둘째, 정규계획 모델과 상호 협조하면서 납기 회답을 지원하는 납기회답 모델의 설계에 대해서 살펴본다. 정규계획 모델과 달라지는 입력 부분의 정의와 정규계획 모델과의 상호 관계를 정의한다. 다음으로, 정해진 납기를 지키기 위해서 정규계획 모델에서 고려래야 하는 요소에 대해서 알아본다. 가장 중요한 것으로 작업 부하와 생산 용량을 고려한 계획 일자(PST)와 고객 납기와 제조 공정 LT를 고려한 계획 일자(LPST)중 최소값을 원자재의 납기 일자로 사용하는 것을 제안한다. 동시에 신규 구매 지시 계획을 생성하기보다는 기존에 발생된 구매 지시의 우선적 사용과 기존 구매 지시의 납기 일자를 고객 납기에 가장 잘 맞출 수 있도록 변경하는 방안을 제시한다. 이렇게 함으로써 최대한 고객 납기를 만족하도록 계획을 수립할 수 있게 된다. 본 논문에서 제시하는 계획 모델을 사용함으로써 고객 주문에 대한 대응력을 높일 수 있고, 계획의 투명성으로 인한 전체 공급망의Bullwhip effect를 감소시킬 수 있는 장점이 있다. 동시에 이것은 향후 e-Business 시스템 구축을 위한 기본 인프라 역할을 수행할 수 있게 된다.

• Journal of Microbiology and Biotechnology
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• v.24 no.4
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• pp.431-439
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• 2014

We report the construction of two Bacillus subtilis expression vectors, pBNS1/pBNS2. Both vectors are based on the strong promoter P43 and the ampicillin resistance gene expression cassette. Additionally, a fragment with the Shine-Dalgarno sequence and a multiple cloning site (BamHI, SalI, SacI, XhoI, PstI, SphI) were inserted. The coding region for the amyQ (encoding an amylase) signal peptide was fused to the promoter P43 of pBNS1 to construct the secreted expression vector pBNS2. The applicability of vectors was tested by first generating the expression vectors pBNS1-GFP/pBNS2-GFP and then detecting for green fluorescent protein gene expression. Next, the mannanase gene from B. pumilus Nsic-2 was fused to vector pBNS2 and we measured the mannanase activity in the supernatant. The mannanase total enzyme activity was 8.65 U/ml, which was 6 times higher than that of the parent strain. Our work provides a feasible way to achieve an effective transformation system for gene expression in B. subtilis and is the first report to achieve B. pumilus mannanase secretory expression in B. subtilis.

• Journal of Microbiology
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• v.43 no.spc1
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• pp.110-117
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• 2005

Salmonella enterica serovar Typhimurium causes human gastroenteritis and a systemic typhoid-like infection in mice. A critical virulence determinant of Salmonella is the ability to invade mammalian cells. The expression of genes required for invasion is tightly regulated by environmental conditions and a variety of regulatory genes. The hilA regulator encodes an OmpR/ToxR family transcriptional regulator that activates the expression of invasion genes in response to both environmental and genetic regulatory factors. Work from several laboratories has highlighted that regulation of hilA expression is a key point for controlling expression of the invasive phenotype. A number of positive regulators of hilA expression have been identified including csrAB, sirA/barA, pstS, hilC/sirC/sprA, fis, and hilD. HilD, an AraC/XylS type transcriptional regulator, is of particular importance as a mutation in hilD results in a 14-fold decrease in chromosomal hilA::Tn5lacZY-080 expression and a 53-fold decrease in invasion of HEp-2 cells. It is believed that HilD directly regulates hilA expression as it has been shown to bind to hilA promoter sequences. In addition, our research group, and others, have identified genes (hilE, hha, pag, and lon) that negatively affect hilA transcription. HilE appears to be an important Salmonella-specific regulator that plays a critical role in inactivating hilA expression. Recent work in our lab has been directed at understanding how environmental signals that affect hilA expression may be processed through a hilE pathway to modulate expression of hilA and the invasive phenotype. The current understanding of this complex regulatory system is reviewed.

• Journal of dental hygiene science
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• v.12 no.2
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• pp.123-129
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• 2012

The aim of study was to compare the color parameters and mean color difference of porcelain specimens by different veneering technique in order to examine the effect of veneering technique on esthetics of yttria-stabilized tetragonal zirconia polycrystalline(Y-TZP) all ceramic restoration. Three groups of square-shaped core ceramic specimens(14mm in diameter and 0.3, 0.5, 0.7 mm) and two groups of veneering ceramic specimen were prepared for analysis. Color parameter($L^*,a^*,b^*$) and color difference of zirconia core squares and core-veneer specimens were measured with ShadeEye $NCC^{(R)}$ spectrophotometer, respectively. Mean color difference(${\Delta}E^*$)were calculated using color difference formula. Two-way analysis of variance(ANOVA) combined with a Tukey multiple-range test were used to analysis the data(${\alpha}=0.05$). ${\Delta}E^*$ values were not significantly affected by core thickness and veneering porcelain(p=0.083). The color differences(${\Delta}E^*$) of core-veneer specimens with 0.5, 0.7 mm-A1,A2,A3.5 shade were mostly below 3.7 which was within the clinically acceptable range, while color differences between 0.3 mm-A1,A2 showed more than 3.7. All-ceramic system has color characteristics that clinicians have to consider when selecting materials. Also, manufacturers of different porcelain systems must make every effort to achieve color reproducibility.

• Journal of Korean Society of Environmental Engineers
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• v.39 no.12
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• pp.741-749
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• 2017

This study aims to provide the technical considerations and implications for the development of soil vulnerability assesment tool based on the review of existing tools and case studies applied both domestically and internationally. For this study, we specifically investigated the basic theories and major features implemented in the screening models abroad. In contrast, one case study of prioritizing the vulnerable districts was presented to identify the research trends in Korea. Our literature review suggested that the characteristic of target areas and contaminants needed to be properly incorporated into soil vulnerability assessment because the current tools in Korea neglected these properties which prevented this tool from being used as a correct measure of soil management and prevention. We also reached the conclusion that in terms of technical aspect, the soil vulnerability assessment tool should be developed based on the physical theory and environmental data that were varied over space and time so that the end-users were able to readily and effectively screen soil vulnerability over large areas. In parallel with technical improvement, great effort needed to be devoted to develop an integrated environmental information system that increased the availability of data and shared various types of environmental data through enhanced multi-agency collaboration.

• Radiation Oncology Journal
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• v.14 no.4
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• pp.265-279
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• 1996

Damage produced by radiation elicits a complex response in mammalian cells, including growth rate changes and the induction of a variety of genes associated with growth control and apoptosis. At doses of 10,000 cGy or greater, the exposed individual was killed in a matter of minutes to a couple of days, with symptoms consistent with pathology of the central nervous system(CNS) including degenerative changes. The nature of the damage in irradiated cells underlies the unique hazards of ionizing radiation. Radiation injury to CNS is a rare event in clinical medicine, but it is catastrophic for the patient in whom it occurs. The incidence of cerebral necrosis has been reported as high as 16% for doses greater than 6,000 cGy. In this study, the effect of radiation on brain tissue was studied in vivo. Jun and p53 genes in the rat brain were induced by whole body irradiation of rat with 600Co in doses between 1 Gy and 100 Gy and analyzed for expression of jun and p53 genes at the postirradiation time up to 6 hours. Northern analyses were done using 1.8 Kb & 0.8 Kb-pGEM-2-JUN/Eco RI/Pst I fragments, 2.0 Kb-php53B/Bam HI fragment and ,1.1 Kb-pBluescript SK--ACTIN/Eco RI fragment as the digoxigenin or [${\alpha}^{32}P$] dCTPlabeled probes for Jun, p53 and ${\beta}$-actin genes, respectively. Jun gene seemed to be expressed near the threshold levels in 1 hour after irradiation of $^{60}$Co in dose less than 1 Gy and was expressed in maximum at 1 hour after irradiation of $^{60}$Co in dose of 30 Gy. Jun was expressed increasingly with time until 5 or 6 hours after irradiation of $^{60}$Co in doses of 1 Gy and 10 Gy. After irradiation of $^{60}$Co in dose between 20 Gr and 100 Gy, the expression of Jun was however increased to peak in 2 hours and decreased thereafter. p53 gene in this study also seemed to be expressed near the threshold levels in 1 hour after irradiation of $^{60}$Co in dose less than 1 Gy and was expressed in maximum at 6 hours after irradiation of $^{60}$Co in dose of 1 Gy, p53 was expressed increasingly with time until 5 or 6 hours after irradiation of $^{60}$Co in dose between 1 Gy and 40 Gy. After irradiation of $^{60}$Co in doses of 50 Gy and 100 Gy, the expression of p53 was however increased to peak in 2 hours and decreased thereafter. The expression of Jun and p53 genes was not correlative in the brain tissue from rats. It seemed to be very important for the establishment of the optimum conditions for the animal studies relevant to the responses of genes inducible on DNA damage to ionizing radiation in mammalian cells. But there are many limitations to the animal studies such as the ununiform patterns of gene expression from the tissue because of its complex compositions. It is necessary to overcome the limitations for development of in situ Northern analysis.