• 한국자원식물학회지
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• 제19권4호
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• pp.480-487
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• 2006

본 연구는 발아율이 낮고 발아가 불균일할 뿐만 아니라 발아소요기간이 긴 고로쇠나무 종자의 발아율 및 발아속도를 향상시키고자 PEG를 이용한 priming 처리를 실시하였던 바 그 결과를 요약하면 다음과 같다. 수분퍼텐셜을 0, -0.25, -0.5, -1.0, -2.0MPa로 각각 조절한 PEG 용액에 3일 동안 침지시켜 priming 처리한 고로쇠나무 종자는 무처리구에 비해 priming 처리구에서 발아율, 평균발아일수, 발아속도 및 발아균일지수가 향상되었다. 특히, -2.0MPa 처리구에서는 가장 높은 효과를 나타내었다. 또한 priming 처리는 무처리구에 비해 휴면율이 낮게 나타나 휴면타파에 효과가 있음을 알 수 있었다. Priming 처리가 종자발아 뿐만 아니라 유묘활력에도 영향을 미치는지 알아보고자 priming 처리 후 발아된 종자로부터 생장한 유묘를 대상으로 상대생장율 및 T/R율을 조사한 결과 -2.0MPa 처리구의 유묘에서 상대생장율은 가장 높고 T/R율은 가장 낮은 것으로 관찰되었다. 이러한 결과로부터 -2.0MPa의 수분퍼텐셜에서 3일 동안 priming 처리하는 것이 고로쇠나무 종자에 있어 가장 합리적인 종자처리 방법이라 할 수 있었다.

• Journal of Microbiology and Biotechnology
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• 제25권2호
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• pp.162-173
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• 2015

The cellular fatty acid composition is important for metabolic plasticity in Rhodobacter sphaeroides. We explored the effects of changing the cellular ratio of unsaturated fatty acids (UFAs) to saturated fatty acids (SFAs) in R. sphaeroides by overexpressing several key fatty acid biosynthetic enzymes through the use of expression plasmid pRK415. Bacteria containing the plasmid pRKfabI₁ with the fabI₁ gene that encodes enoyl-acyl carrier protein (ACP) reductase showed a reduction in the cellular UFA to SFA ratio from 4 (80% UFA) to 2 (65% UFA) and had decreased membrane fluidity and reduced cell growth. Additionally, the ratio of UFA to SFA of the chromatophore vesicles from pRKfabI₁-containing cells was similarly lowered, and the cell had decreased levels of light-harvesting complexes, but no change in intracytoplasmic membrane (ICM) content or photosynthetic (PS) gene expression. Both inhibition of enoyl-ACP reductase with diazaborine and addition of exogenous UFA restored membrane fluidity, cell growth, and the UFA to SFA ratio to wild-type levels in this strain. R. sphaeroides containing the pRKfabB plasmid with the fabB gene that encodes the enzyme β-ketoacyl-ACP synthase I exhibited an increased UFA to SFA ratio from 4 (80% UFA) to 9 (90% UFA), but showed no change in membrane fluidity or growth rate relative to control cells. Thus, membrane fluidity in R. sphaeroides remains fairly unchanged when membrane UFA levels are between 80% and 90%, whereas membrane fluidity, cell growth, and cellular composition are affected when UFA levels are below 80%.

• 한국결정성장학회지
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• 제11권2호
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• pp.67-70
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• 2001

Nanosize $SiO_2$composite particles have been synthesized within reverse micelle via metal alkoxide hydrolysis and condensation. The size of the particles can be controlled by manipulating the relative rates of the hydrolysis and condensation reactions of tetraethoxysilane (TEOS) within the microemulsion. The average size of synthesized particles was about in the size range 14~30nm. The effects of synthesis parameters, such as the molar ratio of water to TEOS, the molar ratio of water to surfactant, and the amount of base catalyst, are discussed.

• 한국양식학회지
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• 제12권2호
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• pp.137-143
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• 1999

The effects of dietary protein level on growth, feed utlization and liver size were studied with juvenile haddock (Melanogrammus aeglefinus) of 6.88$\pm$0.54 g (mean$\pm$SD). Five isoenergetic diets containing 44.4 to 64.7% protein were fed to triplicate groups of 50 fish in a flow-through system for 6 weeks. All fish showed a relative increase of more than 300% in final weight. There were, however, no significant differences (P>0.05) in weight gain (16.1 to 17.3 g) and specific growth rate (2.9 to 3.0) among fish groups. A higher protein diets resulted in a lower feed intake. Feed: gain ratio linearly improved (P<0.05) when protein level increased from 44.4 to 59.7%. The lowest protein efficiency ratio was observed in fish fed the highest protein diet. Hepatosomatic index of fish significantly decreased from 10.7 to 7.3% with an increase in protein level. Results from this study suggest that haddock could grow well even when fed the diet with protein lower than 44.4%.

• 한국초지조사료학회지
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• 제17권4호
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• pp.345-350
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• 1997

수정된 Lincoln용액을사용하여 여러가지 목초의 상대생장율, 뿌리/지상부(RlS)비율, 상대적 뿌리 용적 및 표면적 등을 동시에 비교하기 위하여 수경재배법을 개발하였다. 수정된 Lincoln 용액에서 19가지 초종이 모두 잘 자랐으며, 뿌리특성 연구에 긴요하게 이용될 수 있었다. 상대생장율은 조사기간 동안 이상적으로 일정 값을 유지하며 같은 식물체로 성공적으로 측정할 수 있었다. Group 간과 마찬가지로 group 내에서도 초종간 RlS율에 큰 차이가 있었다. 뿌리 조직밀도는 두과목초나 herb보다 화본과에서 낮았다. 뿌리 면적지수는 화본과 목초와 herb가 높았는데 이 면적지수는 각각 다른 초종의 상대척 根界 평가에 유용하게 이용될 수 있을 것으로 사료되었다.

• 한국농공학회지
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• 제42권4호
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• pp.59-66
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• 2000

This study was carried out to investigated the water requirement of twisted sweet peppers which are cultivated in a green house. The meteorological conditions during the experiment period was close to that of normal year except the temperature and relative humidity. The growth status was improved with the increased saturation ratio. The range of the variation of daily water requirement were very large. The peak consumption occurred in the early August. And the higher saturation ratio resulted in higher water requirement. The total water requirement were about 57.180g/d/plant for pot with 100% (P100) of saturation , about 38.700g/d/plant for pot with 80%(P80) of saturation , about 23,720g/d/plant for pot with 60%(P60) of saturation, and about 53, 390g/d/plant for field cultivation in the green house, respectively. The water requirement was correlated with average ambient temperature and growing status, while no significant correlation were found between water requirement and minimum relative humidity or intensity of solar radiation. And the higher correlation was shown as the saturation ratio was increased. The transpiration coefficients of twisted sweet pepper were 378.0g/g for field cultivation in the green house, 363.3g/g for P100, 338.7g for P80 which was the smallest among pot cultivation , and 472.1g/g for P60 , respectively.

• 한국정밀공학회지
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• 제20권11호
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• pp.142-149
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• 2003

Domain switching effect on crack growth in ferroelectric ceramics under combined electric and mechanical loading is investigated. The shape and size of the switching zone is shown to depend strongly on the relative magnitude between the applied electric field and stress field as well as on the ratio of the coercive electric field to the yield electric field. The toughening mechanism is thought to be ferroelectric domain switching leading to the development of a process zone around the crack. Crack-tip stress intensity factor induced by domain switching for the steady state crack growth is numerically obtained.

• 한국자원식물학회지
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• 제21권1호
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• pp.47-51
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• 2008

홍화의 생장해석을 위하여 3월 1일, 4월 1일, 5월 1일 및 7월 1일에 파종한 홍화의 생육상황과 생장분석에 관한 결과는 다음과 같다. 가. 홍화의 발아기간은 저온기 3월 1일 파종에서 발아까지의 소요기간은 24일이었으며, 4월 1일은 8일이었고 고온기로 갈수록 빨라졌다. 나. 개화소요일수도 3월 1일 파종에서는 104일, 4월 1일에서는 79일, 5월 1일과 7월 1일 고온기 파종에서는 각각 65일과 58일로 단축되었으며 파종기별 생육은 3월 1일에 조기 파종한 것이 가장 좋았다. 다. T/R(Top/Root ratio)율은 줄기 신장기부터 수확기까지 완만하게 증가하였으며 7월 1일 파종은 전반적으로 3월 1일파종과 4월 1일 파종에 비하여 T/R율이 낮았다. 라. RGR(Relative Growth Rate)은 줄기가 신장하는 시기에 가장 높았고 개화기 이후는 급격히 생장량이 둔화되었다. 마. CGR(Crop Growth Rate)은 분지시기에 증가하다가 개화직전에 증가속도가 다소 떨어졌으며 개화기에 다시 증가하여 가장 높았다가 그 이후는 둔화되었다. 바. NAR(Net Assimilation Rate)은 줄기신장기에 가장 높았으며 3월 1일에 조기 파종한 것이 가장 높았다.

• 한국작물학회지
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• 제44권1호
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• pp.11-19
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• 1999

This experiment was conducted with nine wheat geno-types to choose the wheat which has excellent early vigour. 'Vigour 18' and 'ZL 59A' are excellent in the long coleoptile genotype, while 'Amery' and 'Janz' are excellent in the short coleoptile genotype. Responding to the growth stage and nitrogen level, Vigour 18 is predominant in the long coleoptile genogype, while Janz in the short coleoptile genotype. Responding to sowing density and nitrogen level, the higher the sowing density was, the shorter the leaf area of Vigour 18 and Janz. Also the leaf area turned out to larger in the plot fertilized with high nitrogen than in the plot fertilized with low nitrogen. This is true of leaf weight and root weight. Concerning specific leaf area (SLA) and leaf area ratio (LAR), the higher the sowing density was, the SLA tended to grow larger, while the SLA grew larger in the plot fertilized with low nitrogen, as were found in Vigour 18 and Janz. The roots of long coleoptile genotype, Vigour 18, turned out to grow longest on the plot sown with 3 seeds. While the roots of short coleoptile genotype, Janz, grew longest on the plot sown with 2 seeds. The relative growth rate (RGR) was the same at low N rates and high N rates. The RGR was 0.071 and 0.072 g $g^{-1}d^{-1}$ at low N rates and high N rates. The partitioning of RGR into net assimilation rate (NAR) and LAR showed that the average LAR at low N rates was similar to the LAR at high N rates. Variation within each cultivar in the LAR and NAR was small relative to the difference between them at low N rates and high N rates. Above ground mass was 8.2 mg greater at high N rates than low N rates, whereas leaf area was 0.05 $\textrm{m}^2$$kg^{-l}$ greater at high N rates than low N rates. The NAR was similar at low N rates and high N rates, whereas LAR was greater at high N rates (0.05 $\textrm{m}^2$$kg^{-l}$); variation in SLA was responsible for the variation in NAR and LAR both at low N rates and high N rates. NAR was more closely associated with the reciprocal of SLA.

• 한국콘텐츠학회논문지
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• 제13권6호
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• pp.236-245
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• 2013

본 연구는 노인자살증가의 원인을 파악하기 위해 거시적인 측면의 관점에서 노인자살률과 사회 경제적요인의 관련성을 분석하였다. 노인자살의 이론적 배경은 사회학적 관점과 경제학적 관점에 기초하여 설명하였다. 노인자살률의 경제적 요인에는 경제성장률과 실업률 그리고 노인의 경제활동참가율과 상대적 빈곤율(소득불평등율)을 포함하며, 사회적 요인의 범주에 속하는 변수로는 사회복지지출비, 이혼율, 그리고 고령화비 증가율과 노인부양비를 포함한다. 주요 연구결과로는 첫째, 노인의 경제활동참가율이 낮을수록 노인자살률이 높아지는 경향이 있었다. 둘째, 사회복지지출비가 낮을수록 노인자살률이 증가하는 것으로 나타났다. 셋째, 상대적 빈곤율, 고령화비 증가율, 그리고 노인부양비는 공히 이들이 증가할수록 노인자살률도 동시에 증가하는 것으로 나타났다. 끝으로 한국노인자살률의 지속적 증가를 예방하기 위해서 거시적 차원의 사회 경제적 정책방안을 제언하였다.