• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2001년도 추계학술발표대회
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• pp.426-429
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• 2001

The continuous production of L -proline was studied using L-histidine auxotrophic mutant of Corynebacterium acetoacidophilum under various substrate limited conditions. Among the $NH_4\;^+$ $PO_4\;^3$ and L -histidine limited conditions, the highest production of L -proline was observed under the L-histidine limited condition. Under $NH_4\;^+$ and $PO_4\;^3$ limited conditions, no or poor L-proline production was observed, respectively. For the kinetic parameters under L -histidine limitation the specific rate of L -proline production was increased with dilution rate upto $0.1hr^{-1}$ but decreased above $0.1hr^{-1}$. The volumetric rate of L -proline production was showed similar pattern with specific rate. The dried cell weight was gradually increased according to decrease the dilution rate. Specific rate of glucose consumption was proportionally increased with dilution rate. The results of continuous culture (higher production of L-proline at dilution rate $0.1hr^{-1}$) will be used in fed-batch culture for the control of cell growth rate and mass production of L-proline.

• 분석과학
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• 제8권4호
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• pp.427-434
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• 1995

Inductively coupled plasma mass spectrometry combined with the isotope dilution method is used for the determination of lithium. The isotope dilution method is based on the addition of a known amount of enriched isotope (spike) to a sample. The analyte concentration is obtained by measuring the altered isotope ratio. The spike solution is calibrated through so called reverse isotope dilution with a primary standard. The spike calibration is an important step to minimize error in the determined concentration. It has been found essential to add spike to a sample and the primary standard so that the two isotope ratios should be as dose as possible. Since lithium is neither corrosive nor toxic, lithium is used as a chemical tracer in the nuclear power plants to measure feedwater flow rate. 99.9% $^7Li$ was injected into a feedwater line of an experimental system and sample were taken downstream to be spiked with 95% $^6Li$ for the isotope dilution measurements. Effects of uncertainties in the spike enrichment and isotope ratio measurement error at various spike-to-sample ratios are presented together with the flow rate measurement results in comparison with a vortex flow meter.

• 한국미생물·생명공학회지
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• 제23권6호
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• pp.717-722
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• 1995

Using a flocculating Saccharomyes cerevisiae CA-1, an air-lift reactor equipped with a modified settler was used for ethanol fermentation. The effects of conditions such as aeration rate, initial glucose concentration, and dilution rate were studied using the air-lift reactor. In batch fermentation, optimum aeration rate was 0.5 vvm. In continuous fermentation, aeration rate and initial pH were fixed 0.5 vvm and 4.5, substrate concentration and dillution rate were changed 10-15% and 0.1-1.3. The maximum ethanol productivity was shown to be 20.4 g/l$\cdot $h in 10% glucose and 0.7 h$^{-1}$ dilution rate., and optimum operation condition considering the ethanol productivity and glucose utilization ratio was 0.5 h$^{-1}$ dilution rate in 10% glucose concentration.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2013년도 제46회 KOSCO SYMPOSIUM 초록집
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• pp.73-76
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• 2013

The inert gas dilution effect for the stability of a stratified propane premixed flame has been experimentally studied. The addition of inert gases to a stratified premixed flame, which used to be very stable without dilution, makes a flame unstable. The lower equivalence ratio on the outer premixed flame and the lower fuel flow rate through the inner nozzle were observed to be the more stable conditions for the stratified premixed flame with nitrogen or argon dilution. It has been interpreted with the flame structure change such as shift of stoichiometric ratio region in a flame.

• Journal of Microbiology and Biotechnology
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• 제4권1호
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• pp.1-6
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• 1994

Continuous culture was carried out with a recombinant Escherichia coli W3110/pCR185, which encodes trp-operon enzymes when the temperature is shifted from $37^{circ}C\;t;42^{\circ}C$. Under derepressed condition of $42^{\circ}C$. plasmlid stability and gene expression were analysed as function of the dilution rate. The stability of plasmid increased with the dilution rate, but maximal levels of gene expression (tryptophan concentration) and plasmid DNA content were obtained at the lowest dilution rate, $0.075\;hr^{-1}$. The plasmid instability, observed at low dilution rates, could be explained by the unbalanced biosynthetic state of the recombinant cell harboring a high copy number of plasmid.

• 미생물학회지
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• 제21권3호
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• pp.163-169
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• 1983

Effects of temperature on the gorwth characteristics and the chemical composition of pseudomonas cells grown under glucose-or methanol-utilizing continuous culture were studied. In a glucose-utilizing continuous culture, optimum dilution rate, agitation, pH, and temperature, for the higher biomass yield were $0.45hr^-$, 7000rpm, pH 7.5, and $30^{\circ}C$, respectively. But in a methanol-utilizing continuous culture, they were $0.125hr^-$, 600rpm, pH 8, and $30^{\circ}C$, respectively. In methanol-utilizing continuous culture, the maximum production rate of the cells was 1.48g, dry wt./1/hr at a dilution rate of $0.45hr^-$, and the cell yield was 0.46g. dry wt./g. glucose. In the methanol-utilizaing continuous culture, the maximum production rate of the cells was 0.33 7g. dry wt./1/hr. at a dilution rate of $0.125hr^-$ and the cell yield was 0.44g dry cell/g. methanol. The contents of protein of the cells increase with the increase ingrowing temperature (from 15 to $30^{\circ}C$), more or less, while the contents of RNA nad carbohydrate of the cells decreased. However, DNA contents of cells growth under the various temperature ranges didn't change. As the temeprature of cultivation rises at a constant dilution rate, the efficiency of RNA in protein synthesis was increased, showing the decreases in the ratio of RNA to protein.

• Communications for Statistical Applications and Methods
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• 제13권3호
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• pp.787-794
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• 2006

In group testing, the test unit consists of a group of individuals and each group is tested to classify units from a population as infected or non-infected or estimate the infection rate. If the test group is infected, one or more individuals in the group are presumed to be infected. It is assumed in group testing that classification of group as positive or negative is without error. But, the possibility of false negatives as a result of dilution effects happens often in practice, specially in many clinical researches. In this paper, dilution effect models in group testing are discussed and estimation methods of infection rate are proposed when a dilution effect exists.

• Journal of Mechanical Science and Technology
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• 제19권6호
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• pp.1358-1365
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• 2005

Flue gas recirculation (FGR) is widely adopted to control NO emission in combustion systems. Recirculated flue gas decreases flame temperature and reaction rate, resulting in the decrease in thermal NO production. Recently, it has been demonstrated that the recirculated flue gas in fuel stream, that is, the fuel induced recirculation (FIR), could enhance much improved reduction in NO per unit mass of recirculated gas, as compared to conventional FGR in air. In the present study, the effect of dilution methods in air and fuel sides on NO reduction has been investigated numerically by using $N_2$ and $CO_2$ as diluent gases to simulate flue gases. Counterflow diffusion flames were studied in conjunction with the laminar flamelet model of turbulent flames. Results showed that $CO_2$ dilution was more effective in NO reduction because of large temperature drop due to the larger specific heat of $CO_2$ compared to $N_2$. Fuel dilution was more effective in reducing NO emission than air dilution when the same recirculation ratio of dilution gas was used by the increase in the nozzle exit velocity, thereby the stretch rate, with dilution gas added to fuel side.

• 한국식품과학회지
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• 제27권1호
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• pp.129-133
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• 1995

배양환경이 효모 RNA 축적과 autolysis 효율에 미치는 영향을 알아보기 위하여 연속배양을 실시하였다. Dilution rate의 증가에 따라 균체내의 RNA 함량은 증가하여 dilution rate=0.35 $h^{-1}$에서 14.8%를 나타내었고, 더불어 RNA productivity와 specific RNA productivity도 증가하였다. 고정된 D=0.2 $h^{-1}$에서 최적 균체량은 배양온도 $30^{\circ}C$ 에서 얻어졌으나, RNA 함량은 배양온도가 낮아질수록 높은 값을 보여 $24^{\circ}C$에서 12.7%로 나타났다. 한편, autolysis 효율 측면에서 균체 생육속도가 증가할수록 효모 extract의 추출율은 감소하였고, 효모 extract의 분해율은 증가하는 경향을 보였으나, 배양온도는 효모 autolysis 효율에 큰 영향을 미치지 않았다.

• 대한방사선기술학회지:방사선기술과학
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• 제43권2호
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• pp.97-103
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• 2020

This study was conducted by SPECT test at the Department of Nuclear Medicine at Daegu P Hospital from June 1 to October 31, 2019. A 3-way injection material was mounted among inpatients, and a syringe that was administered with radiopharmaceuticals using a ^99mTc labeled compound was secured. We tried to find a way to calculate the dose rate of each radiopharmaceutical and increase the dose rate. As a result of measuring the radioactivity of radio-pharmaceuticals using ^99mTc, the average dose rate of 60 syringes of all 6 radiopharmaceuticals was 93.26±7.34%, and the average dose rate of ^99mTc-DMSA was 77.72%, 15.54% lower than the total. As a way to increase the dosing rate, the average dose rate diluted twice with the remaining amount of syringe after administration using normal saline increased to 95.37±6.99%, and the average dose rate diluted three times increased to 96.32±6.86%. The corresponding sample t-test to compare the pre- and post-dose rates at 1 dilution and 2 and 3 dilutions. As a result of the dilution and 2 dilutions, the probability of significance was 0.013, which was significantly higher than the dilution(p<0.05). The probability of significance for dilution 1 and dilution 3 was 0.016, which was significantly higher than in one dilution(p<0.05). The sum of the average dose rate using the experimental 3-way line was the highest with 98.85±1.42% of ^99mTc, ^99mTc-ECD 98.82±1.26%, ^99mTc-Mebrofenin 98.82 ± 1.16%, ^99mTc-HDP 98.74 ± 1.91%, ^99mTc -MIBI was 98.69 ± 1.48%, and ^99mTc-DMSA was the lowest with 86.47 ± 4.74%. When the number of dilutions was 5 times using 0.5 cc of normal saline and when the number of dilutions was 5 times using 1 cc of normal saline, when the number of dilutions was 5 times using 0.5 cc of normal saline and 1 cc of nomal saline When the number of dilutions was 5 times and the syringe volume was 0.5 cc, there was a statistically significant difference (p<0.05). There was a statistically significant difference when the number of dilutions was 5 times using 1 cc of nomal saline and the number of dilutions was 5 times using 1 cc of normal saline, and the syringe volume was 0.5 cc (p<0.05).