• Applied Biological Chemistry
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• v.38 no.3
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• pp.218-223
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• 1995

Osmolytes accumulated in the osmotically stressed Yersinia enterocolitica ATCC 9610 were investigated using natural abundance $^{13}C$ NMR spectroscopy. Glycine betaine, one of the more common and most effective osmolytes found in nature, was the dominant osmolyte in osmotically stressed Y. enterocolitica cells. Glycine betaine concentration was 41.8 times higher (801.9 nmol/mg protein) in stressed cells than in unstressed cells (19.2 nmol/mg protein). Proline was the minor osmolyte, and its concentration was 284.8 nmol/mg protein. The effects of glycine betaine and related osmolytes on growth rate of osmotically stressed Y. enterocolitica were investigated to identify their ability as osmolytes for Y. enterocolitica. When glycine betaine and proline were added in MMA medium containing 2.5% NaCl, the growth rate with glycine betaine (1 mM) was 3.6 times higher than in control (no addition of osmolyte), and that with proline was 1.3 times higher. Dimethylglycine (5 mM) also increased the growth rate 3.1 folds. On the other hand, monomethylElycine had no effect on growth of osmotically stressed and unstressed Y. enterocolitica. When carnitine was added in MMA medium containing 2.5% NaCl, carnitine (5 mM) increased the growth rate 2.4 folds, but choline had no effect on growth of osmotically stressed Y. enterocolitica. The above results indicate that glycine betaine is the dominant osmolyte in osmotically stressed Y. enterocolitica, and proline, dimethylglycine and carnitine also act as minor osmolytes.

• KSBB Journal
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• v.18 no.4
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• pp.277-281
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• 2003

The study of growth characteristics for Spirulina platensis were carried out in 400 mL cylindrical photobioreactor and the effects of carbon dioxide concentration and flow rate during the growth of Spirulina platensis were investigated. The results showed that relatively low carbon dioxide concentration and high flow rate forced the growth of Spirulina platensis in experiment conditions. The pH analysis showed that different carbon dioxide concentration might form particular aqueous carbonate system in culture medium and affect the growth of Spirulina platensis. In addition, the possibility of limiting light radiation by cell density was investigated by the analysis of specific growth rate. The result intimated that the cause of decrease of specific growth rate at exponential phase was due to the limitation of light radiation by Spirulina platensis cell density in cylindrical photobioreactor.

• Tuberculosis and Respiratory Diseases
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• v.60 no.2
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• pp.187-193
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• 2006

Background : Normal cell proliferation and viability is strongly depends on the availability of metabolic energy and the maintenance of the appropriate adenylate-nucleotide pools. Hypothetically, changes in adenylate kinase (AK) expression could therefore be associated with adaptation to altered growth characteristics or inversely altered growth characteristics of proliferating cells could drive the changes in the metabolic profile. This study investigated whether the expression of either AK1 or a Mycobacterium tuberculosis adenylate kinase mutant which has the same catalytic activity of AK1 could affect the growth rate of slow-growing BCG. Method : Recombinant BCGs, which were cloned the human muscle-type adenylate kinase synthetic gene (AK1) and adenylate kinase mutation gene (AKmtDM) of Mycobacterium tuberculosis into the Mycobacterium/E.coli expression vectors, were constructed. Recombinant BCGs and wild-type BCG were cultured in 7H9 media and the optical density at 600nm was measured at intervals of 2-3 days. Result : There wasn't the growth rate change induced by AK1 or AKmtDM expression in recombinant BCGs. Conclusion : The expression of AK1 or Mycobacterium tuberculosis adenylate kinase mutant in BCG does not affect the growth rate of BCG.

• KSBB Journal
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• v.4 no.3
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• pp.259-265
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• 1989

In a batch fermentation process using carrot cell suspension culture, the effect of initial concentration of limiting nutrients(glucose and phosphate) on the specific growth rate and cell yield was investigated. The period of exponential growth is about 2 days and the consumption of glucose and phosphate in culture medium was very small when the initial concentrations of glucose and phosphate are 1.49g/1 ~ 3.01g/l and 0.08 ~ 0.32mM respectively. The specific growth rate of cells ranged from TEX>$0.15\;day^{-1}$ to $0.3\;day^{-1}$ irregularly. And the ratio of the initial concentration of glucose to phosphate did not affect the specific growth rate and the cell yield. The increase on cells had linear relationship with the consumption of limiting nutrients. Therefore, the increase of cells was found to be more influenced by the concentration of glucose than that of phosphate.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.5 no.3
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• pp.209-214
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• 1995

Abstract 0.2 wt % $Fe_2O_3$ doped $SrTiO_3$ single crystals were grown by floating zone method in air and Nz atmosphere, respectively. The growth rate was fixed at 5 mm/hr and rotation speed was maintained at 30 rpm. As - grown crystals were cut perpendicular to its growth direction and then, annealed at 900, 1000 and $1100^{\circ}C$ for 2 hours in Nz atmosphere. Resistivities of each samples were measured and then converted into conductivities. By using these conductivity values, the activation energies were calculated and by means of the calculated activation energies, mechanism which contribute to increasing the electrical conductivity were investigated.

• The Optical Journal
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• s.119
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• pp.20-23
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• 2009

산업연구원에서 발표한 ‘2009년 경제 산업 전망’에 따르면 우리나라의 2009년 경제성장은 세계경제 침체의 영향으로 작년보다 낮은 3.2% 내외의 성장이 전망된다. 수출은 세계경기 부진, 원자재가 하락에 따른 수출단가 상승세 둔화로 작년에 비해 증가세가 크게 둔화될 전망이며 수입은 수출보다 더 큰 폭으로 둔화될 것으로 보인다. 무역수지는 균형 내지 소폭 흑자가 예상된다. 2009년 산업분야에서 제조업 생산은 작년보다 크게 둔화될 전망이며 특히 IT 제조업은 내수부진이 심화되면서 증가세가 전년보다 둔화되겠지만 환율상승에 따라 원화 기준 수출 증강 힘입어 여타 업종에 비해 상대적으로 높은 증가율을 기록할 전망이다. 10대 주력업종의 수출은 4.4% 증가에 머물고 수입은 전년대비 0.4% 감소할 예정이다.

• Korean Journal of Materials Research
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• v.4 no.1
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• pp.97-106
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• 1994

The dependence of the electrical resistivity on the eutectic composition and growth rates was investigated in the unidirectionally solidified Sb-InSb and Sn-Bi eutectic alloy systems, which were generally classified into the groups of f-f and nf-f eutectic system. Sb-InSb alloys containing 26-34wt.% In and Sn-Bi alloys containing 53-65wt.%Bi were prepared in vacuum sealed in a silica tube, and then these were unidirectionally solidified. Electrical resistivity of the specimens prepared by cutting the crystal section in parallel with the transverse direction and by cutting in longitudinal direction was measured. As the growth rate increased, the Sb-InSb and Sn-Bi eutectic alloys showed that the resistivity of longitudinal to the growth direction was increased but that of transverse to the growth direction was decreased. In the case of Sb-InSb eutectic alloy, increas~ng the phase boundary area and decreasing the fiber directionallity caused to increase the $p \; \parallel$ , while increasing the phase boundary area increased the $p \; \\perp$ As expected, the eutectic microstructure could be analysed well in terms of electrical resistivity.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.39 no.12
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• pp.1257-1263
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• 2015

A correlation between the transient regime and steady state regime on the creep crack growth (CCG) for Grade 91 steel, which is used as the structural material for the Gen-IV reactor systems, was investigated. A series of CCG tests were performed using 1/2" CT specimens under a constant applied load and at a constant temperature of $600^{\circ}C$. The CCG rates for the transient and steady state regimes were obtained in terms of $C^*$ parameter. The transient CCG rate had a close correlation with the steady-state CCG rate, as the slope of the transient CCG data was very similar to that of the steady state data. The transient rate was slower by 5.6 times as compared to the steady state rate. It can be inferred that the steady state CCG rate, which is required for long-time tests, can be predicted from the transient CCG rate obtained from short-time tests.

• Journal of the Korean Ceramic Society
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• v.38 no.1
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• pp.28-33
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• 2001

WC-6%Co 소결체를 열처리할 때 발생하는, 시편 표면에서의 급격한 입자 성장 거동을 열처리 분위기를 변수로 하여 관찰하였다. 열처리 분위기로 수소와 메탄을 각각 사용하였고, 온도는 1400~145$0^{\circ}C$, 압력은 1~3 Torr, 그리고 시간은 100분까지 변화시켰다. 표면에서의 입자 성장은 수소 분위기보다 메탄 분위기를 사용하는 경우 훨씬 빠르게 일어났다. 그리고 열처리 온도가 증가할수록, 압력이 감소할수록 입자 성장 속도가 증가하였다. 이때 성장한 입자의 크기 분포는 비정규 분포를 보였다. 한편, 입자 성장은 열처리시 증발하는 시편의 Co 무게 감소와 밀접한 관계를 보였다. 이러한 표면에서의 입자 성장 현상을 열처리한 조건과 관련되어 WC-Co 상태도에서 예측할 수 있는, 탈탄-탄화 반응 및 비정상 입자 성장 현상 관점으로 설명하였다.

• Korea Petroleum Association Journal
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• no.11 s.227
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• pp.50-55
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• 2001

에너지경제연구원에서 최근 발간한 '에너지수요전망(2001~2006)'에 따르면 우리나라 에너지수요는 향후 5년간 과거의 높은 증가세와는 뚜렷이 구별되는 안정화 추세를 나타낼 것으로 예상된다. 지난 10여년간 우리나라의 에너지소비는 낮은 수준의 에너지가격 지속과 경제성장 및 생활양식 변화를 배경으로 매우 빠른 속도로 증가해 왔다. 그러나 향후 경제성장 속도가 과거에 비해 둔화되고, 에너지안보 및 국제적 환경규제 대응 차원에서 에너지의 효율적 사용이 중요해 짐에 따라 에너지수요는 안정적인 증가추세로 접어들 것으로 전망된다.