• Korean Journal of Fisheries and Aquatic Sciences
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• 제35권4호
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• pp.327-335
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• 2002

Effects of available food on growth of commercially cultured Pacific oysters, Crassostrea gigas in Goseong Bay on the south coast were studied using a numerical model. levels of total protein, carbohydrate and lipid in particulate organic matter in the water column as well as chlorophyll a concentration were determined for estimating total available food for oyster growth. Environmental parameters including water temperature, salinity and total suspended solid were also monitored for the model. Oyster growth was also monitored by means of measuring shell length and tissue wet weight increase on a monthly basis. Simulation results from the numerical model indicated that chlorophyll a is not a good representative of available food for the oysters in Goseong Bay. In contrast, available food in the water column measured by filtration of the organic particles and analyzed in terms of total lipids, carbohydrates and protein was well matched with simulated oyster growth in the Bay which is similar to observed growth. The model also suggested that oysters have relatively low retention efficiency of $50\%$ or less. This result indicates that oysters in the bay utilize only a part of food particle available in the water column, as reported in other studies.

• Ecology and Resilient Infrastructure
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• 제10권4호
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• pp.217-225
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• 2023

This study analyzed the effect of flood level reduction in the case of creating and operating offline storage for the Jangdong district, which can be used as a flood buffer space for the Geumgang River, through one-dimensional unsteady flow numerical simulation. In particular, the sensitivity analysis of changes in the height and width (length) of transverse weirs on flood level changes was performed to provide quantitative information necessary for flood control facility (embankment) design. As a result of analyzing the flood control effect of the offline storage based on the peak flood discharge and level, spatially, the flood control effect at the planned flood buffer space site and the downstream end was confirmed, and it was confirmed that the flood reduction effect at the downstream occurred the most. By design conditions of the transverse overflow weir, the greatest flood reduction effect was found under the condition that the overflow weir height based on the 50-year frequency flood level and the transverse overflow weir width (length) of 125 m were considered. The effect of delaying the time to reach the maximum flood due to the operation of the offline storage site was also presented based on unsteady flow modeling.

• Journal of the Korean GEO-environmental Society
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• 제14권8호
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• pp.29-35
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• 2013

The objective of this research was to investigate the effect of various clay materials on the growth and change in mineral composition of soybean sprout. Further effect of sericite concentration on growth of soybean sprout was optimized. The experiments were carried by using three different viz., loess supernatant, tap water and sericite supernatant. From the obtained results it was found that a significant growth in soybean sprouts was observed while using sericite supernatant this growth was 14.71% and 50% more total growth than that of loess supernatant and tap water. In addition, using sericite supernatant the length of root of soybean sprouts was reached 17.30% and 36.50% longer than that of tap water and loess supernatant. The plausible reason for this growth using sericite supernatant may be due to the presence of various mineral($K^+$, $Ca^+$) in sericite. Further the mineral contents of sericite supernatant were 11.56% and 13.48% more than that for loess supernatant and tap water. Among the various sericite concentration used it was found that 100g/L sericite supernatant showed significant growth rate compared with other fractions. From the obtained results comparing with all materials 100g/L sericite concentration was economic for the cultivation of soybean sprout.

• Korean Journal of Fisheries and Aquatic Sciences
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• 제28권5호
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• pp.589-598
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• 1995

Filtering rates of Crassostrea gigas were experimentally investigated with reference to effects of water temperature and size. Absorptiometric determinations of filtering rates with oysters being fed diatom Chaetoceros calcirtans were carried out in a closed system. Optical density of 675nm in path length 100mm cell used as the indication of food particles absorption was appeared directly In proportion with the concentration of diatom pigment $chlorophyll-\alpha$. In the closed system where $C_0$ is $OD_{675}$ at initial time 0, $C_t$, at time t, and Z is the decreasing coefficient of OD as meaning of instantaneous removal speed, then $C_t=C_0{\cdot} e^{-2t}$, $Z=In(C_t/C_0)/t$. On the assumption that the filtering rate is constant, then removal rate per unit time (d) is $d=-e^{-z}$. If t is used to time unit of hour (hr), the filtering rate (FR) in I/hr is given by $FR=V{\cdot}d=V(1-e^{-z})$, where V is the water volume (I) of the experimental vessel. Filtering rate increased as exponential function with increasing temperature while not over critical limit. The critical temperature for filtering rate was assumed to be between $28^{\circ}C$ and $29^{\circ}C$. And the weight exponent for filtering rate is 0.223. The model formula derived from the results as FR, $Ihr^{-1}$ = $Exp(0.208{\cdot}T-4.324){\cdot} (DW)^{0.223}$ (T<29 $^{\circ}C)$ where T is water temperature $(^{\circ}C

• Biotechnology and Bioprocess Engineering:BBE
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• 제4권1호
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• pp.21-25
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• 1999

Two low-salt complex media, bactopeptone and desalted yeast extract, were used for high density cultivation of the hyperthermophilic archaeon Sulfolobus solfataricus (DSM 1617). Bactopeptone, which has low mineral ion content among various complex media, was good for cell growth in batch cultures; the maximal cell density in bactopeptone was comparable to that in yeast extract. However, cell growth was rather poor when bactopeptone was added by the fed-batch procedure. Since several vitamins are deficient in abctopeptone, the effect of vitamins on cell growth was examined. Among the vitamins tested, pyridoxine was found to improve the growth rate of S. solfataricus. To reduce the growth inhibition caused by mineral ions, yeast extract was dialyzed against distilled water and then fed-batch cultures were carried out using a fed medium containing desalted yeast extract. Although the concentrations of mineral ions in yeast extract were significantly lowered by the dialysis whether low molecular weight solutes in yest extract are crucial for cell growth, we investigated the effect of trehalose, a most abundant compatible solute in yeast extract, on the growth pattern. Cell densities were increased and the length of the lag phase was markedly shortened by the presence of trehalose, indicating that trehalose plays an important role in the growth of S. solfataricus.

• Proceedings of the KSME Conference
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• 대한기계학회 2007년도 춘계학술대회B
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• pp.1882-1887
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• 2007

In the present experimental study, the effect of interfacial tensions on pressure drop of air-water two-phase flow in round mini-channels was investigated. A glass (highly wettable) tube and a Teflon (poorly wettable) tube, both in 350 mm length but 1.8 mm and 1.59 mm in inner diameters each, were used for the tests. All the experiments were performed only in the plug flow regime, confirmed by visualization. In the glass tube, the gas plugs were surrounded by the liquid film along the inner periphery. On the other hand, the inner wall remained dry at the gas portion in the Teflon tube. The pressure drop of the plug flow in the Teflon tube without the liquid film) appeared much larger than in the glass tube (with the liquid film) due to dissipation of energy by movement of the wetting lines. In this paper, various correlations on the two-phase pressure drop of plug flows were compared and a modified correlation was proposed, taking account of the surface wettability.

• Transactions of the Korean Society of Mechanical Engineers
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• 제11권1호
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• pp.105-109
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• 1987

Artificial roughness as a means of improving heat transfer gains more interest, especially for application to various heat exchanger. This study present experimental information for single-phase free and force convection heat transfer in a circular tube containing a internal spiral ribs. To examine the effect of inclined angle of tube, it was varied from 0 deg to 90 deg (0.deg., 22.5.deg., 45.deg., 90.deg.) with horizontal. Length of tube is 1.6m, and width, height and helix angle of rib are 4.2mm, 1.5mm, and 60 deg respectively. Water was used as a working fluid and test piece was heated with a constant heat flux by electric heater. Experiments have been performed with the range of modified Grashof number from 2 * 10$^{6}$ to 15 * 10$^{6}$ for free convection and with the range of Reynolds number from 3,000 to 40,000 for forced convection. Since the increase in heat transfer coefficients influence directly to the friction coefficient of the tube, the changes of the friction factors are also presented for several different cases considered in this investigation.

• Proceedings of the Korean Nuclear Society Conference
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• 한국원자력학회 1997년도 춘계학술발표회논문집(1)
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• pp.356-361
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• 1997

To investigate parametric effect on CHF and to get CHF data, experimental study has been performed with vertical round tubes under the condition of low pressure and low flow (LPLF). Test sections are made of Inconel-625 tube and have the geometry of 8 and 10 mm in diameter, and 0.5 and 1.0 m in heated length. All experiments have been conducted at the pressure of under 9 bar, the mass flux of under 250 kg/$m^2$ and the inlet subcooling of 350 and 450 kJ/kg, for stable upward flow with water as a coolant. Flow regime analysis has been performed for obtained CHF data with Mishima's flow regime map, which reveals that most of the CHF occur in the annular-mist flow regime. General parametric trends of the collected CHF data are consistent with those of previous studies. However, for the pressure effect on CHF, two different are observed; For relatively high mass flux, CHF increases with pressure and far lower mass flux, CHF decrease with pressure. Using modern data regression tool, ACE algorithm, two new CHF correlations for LPLF condition are developed based on local condition and inlet condition, respectively. The developed CHF correlations show better prediction accuracy compared with existing CHF prediction methods.

• Biomedical Science Letters
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• 제19권3호
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• pp.188-194
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• 2013

Ulcerative colitis (UC) is an inflammatory bowel disease, which is a chronic gastrointestinal disorder. Adenophorae Radix (AR) has been used as a traditional medicine for various diseases including strengthening cardiac function, allaying a fever, and easing pain and cough. However, the regulatory effects of AR in intestinal inflammation are not yet understood. This study attempted to determine the effect of AR in dextran sulfate sodium (DSS) - induced colitis in mice. The colitis mice were induced by drinking water containing 5% DSS for 7 days. The results showed that mice treated with DSS showed remarkable clinical signs, including weight loss, and reduced colon length. Administration of AR attenuated weight loss, colon shortening and inhibited the levels of interleukin (IL) - 6 in DSS - treated colon tissues. These results provide experimental evidence that AR might be a useful therapeutic medicine for patients with UC.

• The Journal of Pediatrics of Korean Medicine
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• 제19권1호
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• pp.67-82
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• 2005

Objectives : This study was conducted to find out the effect of Yukmijiwhangtanggamibang (YM) on growth, learning and memory of rats. Methods : It was divided SD rats into Sham group, 192 Saporin injection(SA+Saline) group and Injection of 192 Saporin with YM(SA+YM) group. Growth measure length of bone and tail. Memory performance was used aquisition test and learning retention of morris water maze. It was detected acetylcholinesterase(AChE), cholineacetyltransferase(ChAT) at medial septum and hippocampus by immunohistochemistry Results : Body Weight of the SA+YM Group increased effectively, as compared with SA Saline group. Growth of bone in the SA+YM Group increased effectively, as compared with SA+Saline group. Growth of Tail in the SA+YM Group increased effectively, as compared with SA_Saline group. The SA+YM Group in Aquisition Test improved effectively, as compared with SA+Saline group. The SA+YM Group in Learning Test improved effectively, as compared with SA+Saline group. The numbers of ChAT cells in Medial septum increased effectively, as compared with SA+Saline group. The numbers of ChAT cells in CA1 of Hippocampus increased, but was not effective. Conclusion : These results suggest that YM has an improving effect on the impaired learning through the effects on memory registration and retrieval.