• 유통과학연구
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• 제15권4호
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• pp.25-32
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• 2017

Purpose - The introduction and expansion of the railway network since the 19th century brought revolutionary changes in economic activities, performance, and structure. The purpose of this study is estimating the impact of railroads on the local agricultural and manufacturing structures in the 19th century USA. Research design, data, and methodology - To identify the impact of railroads on local economic structure, county-level panel data from the U.S. census were analyzed using a panel fixed-effect differences-in-differences regression. The empirical investigation focuses on whether railroads changed the overall volume and sectoral composition of the local agricultural sector, and whether they contributed to the growth of the local manufacturing industry and its productivity. Results - The railroad introduction led to the relative decline of the agricultural sector, while encouraging the growth of market-oriented gardening. As such, manufacturing productivity increased by the introduction of railroads, although manufacturing inputs and home manufactures were unaffected. Conclusions - The findings imply that railroads contributed to the growth of market-oriented farming in rural areas, and the rise of productivity in the local manufacturing sector. Meanwhile, evidence of railroad-driven growth for the entire agricultural sector or a massive reallocation of resources from agriculture to manufacturing were not found.

• Journal of Microbiology and Biotechnology
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• 제16권5호
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• pp.689-694
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• 2006

We investigated the potential use of various carbon sources (fructose, glucose, mannose, lactose, and glycerol) for culturing Phaeodactylum tricornutum UTEX-640 in mixotrophic and heterotrophic batch cultures. Concentrations of carbon substrates tested ranged from 0.005 M to 0.2 M. P. tricornutum did not grow heterotrophically on any of the C-sources used, but successive additions of organic carbon in mixotrophic growth mode substantially increased the biomass concentration and productivity relative to photoautotrophic controls. The maximum biomass productivities in mixotrophic cultures for glycerol, fructose, and glucose were 21.30 mg/l h, 15.80 mg/l h, and 10.20 mg/l h, respectively. These values were respectively 10-, 8-, and 5-fold higher than those obtained in the corresponding photoautotrophic control cultures. Mannose and lactose did not significantly affect microalgal growth. The biomass lipids, eicosapentaenoic acid (EPA) and pigments contents were considerably enhanced with glycerol and fructose in relation to photoautotrophic controls. The EPA content was barely affected by the sugars, but were more than 2-fold higher in glycerol-fed cultures than in photoautotrophic controls.

• Fisheries and Aquatic Sciences
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• 제15권4호
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• pp.305-311
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• 2012

We investigated compensatory growth of Nile Tilapia Oreochromis niloticus in structural size and live weight in response to different deprivation periods and refeeding. Four treatments were assigned randomly to fish in 12 glass tanks, with each treatment performed in triplicate. The control group was fed to satiation three times a day throughout the experiment. The other three treatment groups were starved for 1 week (S1), 2 weeks (S2), or 4 weeks (S4) and then fed until the end of the experiment. After the experiment, no significant differences were observed among S1, S2, and the control group in average weight or length, whereas the weight and length of S4 were significantly reduced. Relative condition factors of the three starved groups decreased significantly until the end of the restricted period but recovered rapidly after refeeding. The specific growth rate in weight ($SGR_W$) of the three restricted groups recovered quickly upon refeeding and were significantly higher than the control group, but these differences disappeared gradually until the end of the experiment. No significant difference in specific growth rate in length ($SGR_L$) was noted between the control group and the three restricted groups after refeeding. All three groups showed hyperphagia for a short period upon refeeding, and no statistical differences were observed in feeding efficiency among the four groups.

• 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%.

• 대한기계학회논문집
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• 제19권2호
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• pp.475-485
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• 1995

In this study, statistical analysis of fatigue data which had obtained from respective 24 fatigue crack, was examined for SiC whisker reinforced aluminium 6061 composite alloy (SiC$_{w}$/A16061) and aluminium 6061 alloy. SiC volume fraction in composite alloy is 25%. The analysis results stress intensity factor range and 0.1 mm fatigue crack initiation life for SiC$_{w}$/A16061 composite & A16061 matrix are the log-normal distribution. And regression analysis by linear model, exponential model and multiplicative model were performed to find out the relationship between fatigue crack growth rate(da/dN) and stress intensity for find out the relationship between fatigue crack growth rate(da/dN) and stress intensity factor range(.DELTA.K) in the SiC$_{w}$/A16061 composite and examine the applicability of Paris' equation to SiC$_{w}$A16061 composite. Also computer simulation was performed for fatigue life prediction of SiC$_{w}$/A16061 composite using the statistical results of this study.udy.

• Asian-Australasian Journal of Animal Sciences
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• 제15권10호
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• pp.1378-1385
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• 2002

The importance of direct genetic, maternal, heterosis and epistatic effects were examined on post-weaning weight, height, length, girth, fat depth and muscle (ratio of stifle to hip width) with dry and wet season gains in these traits. The breeds used were two pure breeds (Jersey and Limousin), the Limousin${\times}$Jersey $F_1$, and two backcrosses ($F_1{\times}$Jersey dams and $F_1{\times}$Limousin dams). Direct genetic effects were large (p<0.001) for all traits except for length. Jersey maternal effects were large for weight, girth, fat depth and muscle in the post-weaning wet season gains which is an evidence of the impact of Jersey dam on progeny beyond weaning. There were large heterosis effects on fat depth and muscle relative to other traits. Epistatic effects were observed for post-weaning performance in weight, girth, fat depth and muscle. There are indications that there were different genetic effects for post-weaning compared to preweaning growth traits. Thus, it could be hypothesized from this study that different quantitative trait loci (QTL) affect early and late growth in Jersey and Limousin cross cattle breeds. The follow up work will examine the different chromosomal gene effects on pre- and post-weaning growth.

• 한국유기농업학회지
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• 제25권4호
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• pp.805-819
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• 2017

The study was carried out to develop a mathematical model for evaluating the effect of organic fertilizers in organic rice production systems. A function to simulate the nitrogen mineralization process in the paddy soil has been developed and integrated into ORYZA2000 crop growth model. Inorganic nitrogen in the soil was estimated by single exponential models, given temperature and C:N ratio of organic amendments. Data collected from the two-year field experiment were used to evaluate the performance of the model. The revised version of ORYZA2000 provided reasonable estimates of key variables for nitrogen dynamics and crop growth in the organic rice production systems. Coefficient of determination between the measured value and simulated value were 0.6613, 0.8938, and 0.8092, respectively for soil inorganic nitrogen, total dry matter production, and rice yield. This means that the model could be used to quantify nitrogen supplying capacity of organic fertilizers relative to chemical fertilizer. Nitrogen dynamics and rice growth simulated by the model would be useful information to make decision for organic fertilization in organic rice production systems.

• 한국세라믹학회지
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• 제32권8호
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• pp.950-956
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• 1995

Y2O3 thin films were deposited by reactive sputtering of Y target in Ar and O2 gas mixture. Residual stress was measrued by sin2$\psi$ method of x-ray diffraction (XRD) and growth orientation was examined by measuring the relative intensity of (400) plane and (222) plane of Y2O3 films. In the case that Y2O3 films were deposited at 40$0^{\circ}C$ and at low working pressure below 0.05 torr the film had large compressive stress and (111) plane orientation. At working pressure of about 0.10 torr the film had small compressive stress and (100) orientation. Above working pressure of 0.20 torr, the films had nearly zero stress and random orientation. In the case that the (111) oriented film deposited at low working pressure below 0.05 torr, as substrate temperature decreased, (111) orientation increased. In the case the film, with (100) orientation, deposited at working pressure of about 0.10 torr, (100) orientation increased with decresing substrate temperature. These relationship of residual stress and growth orientation can be explained by the relationship of surface energy and strain energy.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.480.1-480.1
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• 2014

In this study, we suggest the new emitter formation applied solid phase epitaxy (SPE) growth process using rapid thermal process (RTP). Preferentially, we describe the SPE growth of intrinsic a-Si thin film through RTP heat treatment by radio-frequency plasma-enhanced chemical vapor deposition (RF-PECVD). Phase transition of intrinsic a-Si thin films were taken place under $600^{\circ}C$ for 5 min annealing condition measured by spectroscopic ellipsometer (SE) applied to effective medium approximation (EMA). We confirmed the SPE growth using high resolution transmission electron microscope (HR-TEM) analysis. Similarly, phase transition of P doped a-Si thin films were arisen $700^{\circ}C$ for 1 min, however, crystallinity is lower than intrinsic a-Si thin films. It is referable to the interference of the dopant. Based on this, we fabricated 16.7% solar cell to apply emitter layer formed SPE growth of P doped a-Si thin films using RTP. We considered that is a relative short process time compare to make the phosphorus emitter such as diffusion using furnace. Also, it is causing process simplification that can be omitted phosphorus silicate glass (PSG) removal and edge isolation process.

• 한국식생활문화학회지
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• 제10권1호
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• pp.19-28
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• 1995

The relationship of obesity and related behaviors was analyzed among 361 primary school children, 4th and 5th grade, in one of private school in Seoul in July 1994. Compared to 1985 Korean Children's Growth Standard, the surveyed children have shown remarkable growth, which is the secular trend in growth of Korean children accompanied with rapid economic growth. But the relative incremental weight was far larger than that of height and this trend was more evident among children over 50th percentile, which shows a wide prevalence of obesity of the surveyed children. By WLI index, 15% of the children was overweight and 13% was obese. The higher the WLI, the more frequent and stronger stress they had. The nutrition knowledge score of obese children was higher compared to others. They were especially sensitive to their physical fitness but many normal or underweight-children also experienced stress due to their body weight and have tried to lose weight by incorrect methods. On the other hand many obese children thought they were optimal or underweight. These results reasserts the importance of nutrition education focused on children aheading puberty. They need to know the correct degree of obesity and to get appropriate education through teachers, dietitians, parents and doctors. The findings of this study could be applied to a nutrition implementation policy to ensure better physical fitness of children aheading puberty in the future.