• 한국해양공학회지
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• 제21권2호
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• pp.22-34
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• 2007

We present basic data for developing new research topics and closely examine the existing data on the development and organization of the Nakdong River Estuary Delta by analyzing various studies of the area, including ocean engineering, coastal engineering, ocean environmental engineering, geomorphological, and geological studies. We first defined the general concepts related to the estuary and delta and reviewed the historical development of the Nakdong River Estuary Delta over the past 100 years. We then examined the origin and core elements of the estuary deposits that constitute the delta. In addition, we scrutinized the main factors affecting the development of the delta and analyzed existing research on delta development mechanisms by core researchers. The construction of an estuary barrage is one of the main factors effecting estuarine circulation and has altered the physical oceanic environment, area of deposition, atmospheric environment, and vegetation community of the delta. These factors affect the estuary circulation in turn, altering the delta. Along the Nakdong River, an unsteady-state sandy barrier appears at approximately three times the distance of the wavelength of incident offshore waves, and this terrain forms approximately 10-15 years after reclamation in the interdistributary upper stream and transforms the shoreline. It is necessary to develop a technique to predict terrain change that reproduces the erosion and accumulation of estuarine deposits. To determine the parameters and variables necessary to reproduce this system, continuous on-site monitoring is necessary. The existing research did not fully examine the terrain changes in Nakdong River Estuary or the periodic developmental characteristics. To understand the future process of estuary delta development, it is necessary to establish an integrated management system.

• 한국수산과학회지
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• 제28권4호
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• pp.469-474
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• 1995

[ $3\beta-$ ]히드록시-$\Delta^5$-스테로이드 탈수소효소 ($3\betaβ-HSD,$ $3\beta-hydroxy-\Delta^5-steroid\;dehydrogenase$ $\Delta^5$-스테로이드$\rightarrow\Delta^4$-스테로이드로의 대사경로에 관여하는 효소)에 대하여 특이적 저해제인 cyanoketone과 trilostane의 저해 효과가 $^3H-pregnenolone$ 전구체를 이용하여 무지개송어 난소에서 분리한 여포층, 협막층(theca layers)을 대상으로 비교 관찰되었다. Pregnenolone으로부터 $17\alpha-hydroxyprogesterone$으로의 대사과정에서 주요 효소인 $(3\beta-HSD$ 활성은cyanoketone $10^{-6}$과 $10^{-5}\;M$, 그리고 trilostane $10^{-5}$과 $10^{-4}\;M$의 농도에서 억제되었으며, trilostane이 cyanoketone보다 더 효과적인 억제반응을 보이는 것으로 나타났다. Pregnenolone으로부터 $\Delta^4$-스테로이드 대사물 축적에 대한 trilostane의 저해작용은 사용한 농도 즉, $10^{-8}, 10^{-7}, 10^{-6}$ 그리고 $10^{-5}\;M$에 비례하여 나타났으나 완전한 저해효과는 보이지 않았다.

• Journal of Electrical Engineering and Technology
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• 제6권3호
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• pp.384-390
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• 2011

To evaluate the condition of stator winding insulation in generators that have been operated for a long period of time, diagnostic tests were performed on the stator bars of a 500 MW, 22 kV generator under accelerated thermal and electrical aging procedures. The tests included measurements of AC current (${\Delta}I$), dissipation factor ($tan{\delta}$), partial discharge (PD) magnitude, and capacitance (C). In addition, the AC current test was performed on the stator winding of a 350 MW, 24 kV generator under operation to confirm insulation deterioration. The values of ${\Delta}I$, ${\Delta}tan{\delta}$, and PD magnitude in one stator bar indicated serious insulation deterioration. In another stator bar, the ${\Delta}I$ measurements showed that the insulation was in good condition, whereas the values of ${\Delta}tan{\delta}$ and PD magnitude indicated an incipient stage of insulation deterioration. Measurements of ${\Delta}I$ and PD magnitude in all three phases (A, B, C) of the remaining generator stator windings showed that they were in good condition, although the ${\Delta}tan{\delta}$ measurements suggested that the condition of the insulation should be monitored carefully. Overall analysis of the results suggested that the generator stator windings were in good condition. The patterns of PD magnitude in all three phases (A, B, C) were attributed to internal discharge.

• 한국전기전자재료학회논문지
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• 제19권9호
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• pp.800-807
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• 2006

To enhance the conversion speed more fast, we separate the determination process of MSB and LSB with the two independent ADC circuits of the Incremental Sigma Delta ADC. After the 1st Incremental Sigma Delta ADC conversion finished, the 2nd Incremental Sigma Delta ADC conversion start while the 1st Incremental Sigma Delta ADC work on the next input. By determining the MSB and the LSB independently, the ADC conversion speed is improved by two times better than the conventional Extended Counting Incremental Sigma Delta ADC. In processing the 2nd Incremental Sigma Delta ADC, the inverting sample/hold circuit inverts the input the 2nd Incremental Sigma Delta ADC, which is the output of switched capacitor integrator within the 1st Incremental Sigma Delta ADC block. The increased active area is relatively small by the added analog circuit, because the digital circuit area is more large than analog. In this paper, a 14 bit Extended Counting Incremental Sigma-Delta ADC is implemented in $0.25{\mu}m$ CMOS process with a single 2.5 V supply voltage. The conversion speed is about 150 Ksamples/sec at a clock rate of 25 MHz. The 1 MSB is 0.02 V. The active area is $0.50\;x\;0.35mm^{2}$. The averaged power consumption is 1.7 mW.

• Journal of Microbiology and Biotechnology
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• 제28권12호
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• pp.2009-2018
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• 2018

Leuconostoc mesenteroides can be used to produce mannitol by fermentation, but the mannitol productivity is not high. Therefore, in this study we modified the chromosome of Leuconostoc mesenteroides by genetic methods to obtain high-yield strains for mannitol production. In this study, gene knock-out strains and gene knock-in strains were constructed by a two-step homologous recombination method. The mannitol productivity of the pat gene (which encodes phosphate acetyltransferase) deletion strain (${\Delta}pat::amy$), the fk gene (which encodes fructokinase) deletion strain (${\Delta}fk::amy$) and the stpk gene (which encodes serine-threonine protein kinase) deletion strain (${\Delta}stpk::amy$) were all increased compared to the wild type, and the productivity of mannitol for each strain was 84.8%, 83.5% and 84.1%, respectively. The mannitol productivity of the mdh gene (which encodes mannitol dehydrogenase) knock-in strains (${\Delta}pat::mdh$, ${\Delta}fk::mdh$ and ${\Delta}stpk::mdh$) was increased to a higher level than that of the single-gene deletion strains, and the productivity of mannitol for each was 96.5%, 88% and 93.2%, respectively. The multi-mutant strain ${\Delta}dts{\Delta}ldh{\Delta}pat::mdh{\Delta}stpk::mdh{\Delta}fk::mdh$ had mannitol productivity of 97.3%. This work shows that multi-gene knock-out and gene knock-in strains have the greatest impact on mannitol production, with mannitol productivity of 97.3% and an increase of 24.7% over wild type. This study used the methods of gene knock-out and gene knock-in to genetically modify the chromosome of Leuconostoc mesenteroides. It is of great significance that we increased the ability of Leuconostoc mesenteroides to produce mannitol and revealed its broad development prospects.

• 환경위생공학
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• 제9권1호
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• pp.89-96
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• 1994

This report was investigate the biological characteristic of $\delta$-endotoxin of product by TH109 strain, one strain TH109 which has toxicity on Cockroach is isolate and identification. Generally the $\delta$-endotoxin of product by 3. thuringiensis strain was easily soluble in acid, alkaline and organic solvents but $\delta$-endotoxin of product by TH109 strain are insoluble in HCI, NaOH Thiol- reagent(25mM Dithiotheritol, 25mM Dithioeryritol, 25mM Nathioglycolate, 0.2M ESCN, 2% v/v $\beta$-mecaptethanol), organic solvents( acetone, $CCI_{4}$, ether, dioxin MeOH chloroforrh xylene ), Protease. Through this study of $\delta$-endotoxin produced by TH109 strain is insoluble in acid, alkaline, organic solvents and pretense etc. In the point of view, it is greater possibility that $\delta$-endotoxin will be transform into toxin by the reducible materials instead of the reaction of protease in the intestine.

• Applied Biological Chemistry
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• 제36권1호
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• pp.29-32
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• 1993

Latex(Hevea Brasiliensis)로부터 3종의 ${\alpha}-,\;{\gamma}-,\;{\delta}-tocotrienol$을 각각 분리하고, oil 상태의 각 성분을 얻었다. Tocotrienol을 분리하기 위하여, latex에서 추출한 조지방 성분의 비비누화분획으로 부터 semipreparative HPLC에 의한 분리방법을 사용하여 tocotrienol을 분리하였다. 이와 같은 분리방법을 이용하였을 때 latex에 함유된 tocotrienol의 함량은 약 400ppm이었으며, 순도는 ${\alpha}-,\;{\gamma}-,\;{\delta}-tocotrienol$ 각각 98.3, 99.3, 96.2%로 나타났다.

• 천문학회보
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• 제41권2호
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• pp.58.3-58.3
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• 2016

The Kepler space mission provides quantitative and qualitative photometric time series of oscillating stars. It is possible to examine statistical study with seismic properties of solar-like stars. Global seismic properties - large frequency separation (${\Delta}{\nu}$), frequency of maximum power (${\nu}_{max}$) and amplitude of Gaussian envelope (A) widely have been used to determine empirical scaling relations for inferring the stellar physical quantities - mass, age and temperature. We aim to confirm whether width of Gaussian envelope on power excess (${\delta}{\nu}_{env}$) can be used with parameter of scaling relation before redgiant phase using Kepler data. Therefore we analyze the characteristics of ${\delta}{\nu}_{env}$ of 129 solar-like stars from main-sequence to subgiant. We have demonstrated that ${\delta}{\nu}_{env}$ has highly correlations with global parameters - ${\Delta}{\nu}$ and ${\nu}max$. We have also found the break of ${\delta}{\nu}_{env}-{\Delta}{\nu}$ and ${\nu}_{max}$ relations.

• 한국세라믹학회지
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• 제33권3호
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• pp.327-331
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• 1996

$\delta$-FeOOH was prepared by rapid oxidation method of Fe(OH)2 using H2O2. The effects of reaction temperature and mole ratio ([OH-]/[Fe2+])의 몰비를 제조 변수로 하여 최종 생성된 $\delta$-FeOOH의 입자크기 입자형태, 자기특성을 조사하였다. Fe(OH)2 의 반응온도 및 [OH-]/[Fe2+] 비가 $\delta$-FeOOH의 입자크기 및 형상에 많은 영향을 미침을 알수 있었으며 입자 크기는 이 두인자에 비례하여 증가하였다 Fe(OH)2 의 반응온도가 4$0^{\circ}C$ [OH-]/[Fe2+]=5 Fe(OH)2 숙성 시간 2시간에서 제조된 $\delta$-FeOOH를 TEM, VSM으로 입자의 크기 및 자기특성을 조사한결과 평균 입경이 630$\AA$ 정도이고 입도 분포가 양호하였으며 포화자화 및 보자력은 각각 20.8emu/g 210 Oe였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 E
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• pp.2093-2096
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• 1999

This paper describes to access the insulation deterioration condition of the stator windings in three large turbine generators. Nondestructive tests have been carried out on stand-still generators which have been in service for 2 to 30 years. In most cases these tests include ac current increase rate($\Delta$I), delta tan delta( ${\Delta}tan{\delta}$), and maximum partial discharge(Qm). Gen. 2 show that the $tan{\delta}$ is higher than other two generators in the $tan{\delta}$-voltage curve. Partial discharge(PD) patterns were observed internal, corona and treeing discharges in large turbine generators. The PD tests were confirmed the correlation between discharge patterns and the kinds of defects.