• Journal of the Korea Institute of Military Science and Technology
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• v.10 no.3
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• pp.43-50
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• 2007

A range-frequency interference pattern is analyzed in the course of the propagation of ship noise in shallow water. It has been shown to exhibit striated bands of intensity maxima and minima in the spectrogram. The slope of the striations is an invariant of the modal interference and is described by a waveguide invariant parameter $\beta$. It turns out that this interference pattern is useful for identifying the physical properties of the waveguide such as seabed properties. In this article, the interference pattern is analyzed using image processing techniques to produce the distribution of the beta and the effects of sediment types and geoacoustic parameters on beta distribution are examined and characterized by moments of the distributions.

• The Journal of Engineering Geology
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• v.3 no.2
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• pp.203-214
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• 1993

Underground Injection Control regulations for Class I injection wells require that the vertical dufusion be considered as a mechanism for transport of contaninants in evaluating containment Due to the low permeability in the confining aquitard, the movement of contaminants over the long term is controlled by the molecular diffusion. The movement can be predicted, using the Fick' S second law of diffusion. The diffusion coefficient in Fick' s law has been determined experimentally in this study. Instantaneous injection of $^{51}Cr$ was used to trace the distribution of Cr(VI) in soil plugs and an analytical solution was applied to calculate the diffusion coefficients. This study shows the effect of environmental factors, such as temperature, chloride concentration, applied amount of $^{51}Cr$, and bulk density of injection formations on diffusion of Cr(VI)

• Proceedings of the Korea Water Resources Association Conference
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• 2008.05a
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• pp.689-694
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• 2008

댐 유입량은 댐 운영의 필수 인자이기 때문에 매우 중요하고, 하천유량에 비해 신뢰도가 높은 것으로 평가되고 있기 때문에 수자원의 운영 뿐 아니라 계획에도 활용되고 있다. 그러나 계산된 유입량은 평갈수기에 진폭이 너무 크게 나타나고 심지어 음 유입량이 발생하는 등 개선이 요구돼 왔다. 본 연구에서는 시간간격을 10분, 30분, 1시간 등으로 하고, 수위와 방류량이 유입량에 직접 영향을 끼치고, 관측수위의 단위가 크고, 그 진폭이 자연현상과 거리가 있어, 수위 이동평균, 수위 보간, 방류량 이동평균 등의 조합에 따라 댐 유입량의 계산을 개선할 수 있는 방법을 제안하였고, 이를 쉽게 분석, 평가할 수 있도록 시스템으로 개발하였으며, 유역면적 $4,134km^2$인 대청댐과 유역면적 $108,335mi^2$인 미국의 Lake Powell의 사례에서 크게 개선된 결과를 보여주었다. 그러나 정확하게 측정된 댐 유입량 자료가 없기 때문에 개선된 계산 유입량이 참 값이다 주장할 수 없는 것이 본 연구의 한계이며, 연구결과의 신뢰를 높이기 위해 현재 정밀하게 측정된 댐 유입량 사례를 조사 중에 있다. 그림 1은 Lake Powell의 처리전의 댐 유입량 계산 예이고 그림 2는 처리후의 개선된 유입량이다. 그림에서 유입량이 크게 개선돼 계산된 것으로 나타나고 있으나 결과가 참값인지 아직 판단할 수 없다. 대청댐의 경우도 이와 비슷한 결과를 보여주었다.

• Journal of Biosystems Engineering
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• v.29 no.2
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• pp.141-150
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• 2004

우리가 소비하는 가공 식품은 위생상 안전하도록 살균처리가 이루어진다. 식품 내에 존재할 수 있는 유해 세균은 일정 살균온도에서 살균에 필요한 시간 동안 노출되면 사멸하며, 일반적으로 살균온도가 높을수록 살균에 필요한 시간은 단축된다. 연속살균장치는 혼합 및 저장탱크에 담겨진 식품을 점프로 이동시키면서 가열 열교환기에서 살균온도로 가열하고 단열관을 거치는 동안 살균온도를 유지시켜 살균을 완료한다. 또한 살균된 식품은 냉각용 열교환기에서 상온으로 냉각되며 이 과정에서 회수되는 열은 저장탱크에서 유입되는 식품의 예열에 사용되어 에너지 효율을 제고하는데 사용되기도 한다. 이와 같이 관을 이동하면서 가열되는 살균장치는 기존의 배치식 살균방법에 비하여 균일하게 가열이 이루어지므로 130C의 고온으로 살균할 수 있어서 살균에 필요한 시간을 수초에서 수십초 정도로 단축시킬 수가 있고 그에 따라 열손상을 크게 줄일 수 있다. 또한, 상온으로 냉각된 식품을 포장함으로써 저렴한 가격의 포장용기를 사용할 수 있고 상온에서 저장할 수 있으므로 저장비용이 저렴한 장점이 있다. 그러나, 가공식품에 고기나 야채와 같은 고체 상태의 식품이 함유된 경우에는 액상 식품이 열 교환기에서 순간 가열되며, 고상 식품은 액상식품과의 대류에 의한 열전달로 가열된다. 이 과정에서 고상식품은 이동관 내벽이나 다른 고상식품과 부딪치거나 회전하면서 이동관 내부에서 자유롭게 운동하게 된다. 이 과정에서 액상식품과의 상대이동 속도가 발생하여 이것이 대류열전달에 영향을 미치게 된다. 이 상대이동속도에 따른 대류 열전달계수는 고상식품의 내부온도 결정에 사용되는 연속살균장치의 중요한 설계인자이다. 대류열전달계수는 연속살균장치에서 자유로이 이동하는 고상식품의 중심부의 온도를 측정하여 결정할 수 있으나 이는 현실적으로 어렵다. 따라서 본 연구에서는 고정된 고상식품에 액상식품을 이동시켜 상대속도를 재현하고 액상식품의 온도와 고상식품의 중심온도를 측정하는 장치를 개발하였으며, 각 상대속도와 액상식품의 점도 별 대류열전달계수를 결정하는 프로그램을 유한차분법을 이용하여 개발하였다. 이 장치를 분당 15, 30, 40 리터의 유량에서 유체의 점도를 0에서 15 centipoise 사이의 세 수준에서 정육면체 소고기를 모델 고상식품으로 내부 온도분포를 측정하였으며, 유한차분법 프로그램으로 대류열전달계수를 결정하였다. 대류열전달계수는 792에서 2,107 W/m$^2$로 분석되었다. 대류열전달 계수는 액상식품과의 상대속도가 증가함에 따라서 증가하였고, 점도가 증가함에 따라서는 감소하였다.

• Clinical and Experimental Pediatrics
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• v.45 no.9
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• pp.1106-1113
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• 2002

Purpose : Nuclear ($factor-{\kappa}BNF-{\kappa}B$) is now recognized as playing a potential role in programmed cell death and the adaptive response to various stress. Cellular hypoxia is a primary manifestation of many cardiovascular diseases. It seems that vascular endothelial growth factor (VEGF) and insulin like growth factor-I(IGF-I) have a function as a protective molecule in the heart against several stress including hypoxia. In this study, the role of $NF-{\kappa}B$ to the cellular response and regulation of protective molecules against the acute hypoxia in the heart was studied. Methods : To cause acute hypoxic stress to the heart, Sprague Dawley rats were exposed to hypoxic chamer($N_2$ 92% and $O_2$ 8%). After the hypoxic exposure, nuclear proteins, total proteins and mRNA were isolated from heart. Translocation of the transcription factors $NF-{\kappa}B$, NF-ATc, AP-1 and NKX-2.5 were evaluated by electrophoretic mobility shift assay(EMSA). The expression of IGF-I and VEGF were studied before and after the hypoxic stress by competitive-PCR, Northern hybridization and Western hybridization. To confirm the role of the $NF-{\kappa}B$ in the heart, the rats also were pretreated with diethyl-dithiocarbamic acid(DDTC) into peritoneal cavity to block $NF-{\kappa}B$ translocation into nucleus. Results : The expression of $NF-{\kappa}B$, AP-1 and NF-ATc were increased by the hypoxic stress. Increased expression of the VEGF and IGF-I were also observed by the hypoxic stress. However, the blocking of the $NF-{\kappa}B$ translocation reduced those expressions of VEGF and IGF-I. Conclusion : These results suggest that $NF-{\kappa}B$ has a protective role against the acute hypoxia through several gene expression, especially VEGF and IGF-I in heart muscle.

• Progress in Medical Physics
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• v.10 no.1
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• pp.17-22
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• 1999

INJ-I, INJ-E, PFN, BMI, and PRF were selected among the various factors which constitute a digital linear accelerator to find effects on the dose distribution by changing current and voltage within the permitted scale which Mevatron automatically maintained. We measured the absorbed dose using an ion chamber, analyzed the waveform of beam output using an oscilloscope, and measured symmetry and flatness using a dosimetry system. An RFA plus (Scanditronix, Sweden) device was used as a dosimetry system. Then an 0.6cc ion chamber (PR06C, USA), an electrometer (Capintec192, USA), and an oscilloscope (Tektronix, USA) were employed to measure the changes on the dose distribution characteristics by changing the beam-tuning parameters. When the currents and the voltages of INJ-I, INJ-E, PFN, BMI, and PRF were modified, we were able to see the notable change on the dose rate by examining the change of the output pulse using the oscilloscope and by measuring them using the ion chamber. However, the results of energy and flatness graph from RF A plus were almost identical. The factors had fine differences: INJ-I, INJ-E, PFN, BMI, and PRF had 0.01∼0.02% differences in D10/D20, 0.1∼0.2 % differences in symmetry, and 0.1∼0.4% differences in flatness. Since Mevatron controlled itself automatically to keep the reference value of the factor, it was not able to see large differences in the dose distribution. There were fine differences on the dose rate distribution when the voltage and the currents of the digitized factors were modified Nonetheless, a basic operational management information was achieved.

• Journal of Korean Ophthalmic Optics Society
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• v.18 no.4
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• pp.541-548
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• 2013

Purpose: Marrow stromal cells (MSCs) have been known for their potential to trans-differentiate into neural and glial cells in vitro and in vivo. To investigate the influence of the developing host environment on the survival and morphological and molecular differentiation, murine MSCs transplanted into the eye of Brazilian opossum (Monodelphis domestica). Methods: Enhanced green fluorescent protein (GFP) - expressing MSCs were transplanted into developing Brazilian opossums. Animals were allowed to survive for up to 4 weeks after transplantation, at which time the eyes were prepared for immunohistochemical analysis. Results: Some transplanted MSCs survived and showed morphological differentiation into neural cells with some processes within the host vitreous chamber. Some transplanted cells expressed class III ${\beta}$-tubulin (TuJ1, a marker for neuronal cells) or glial fibrillary acid protein (GFAP, a marker for glial cells) or Nestin (a marker for neural stem cells). In addition, some transplanted cells were located in ganglion cell layer but did not show morphological and molecular differentiation. Conclusions: Our result show that the most effective stage of development for transplantation into the retina was postnatal day 16, which retinas developmentally corresponded to postnatal day 4-5 days mouse retina based on cell differentiation and lamination patterns. The present findings suggest that the age of the host appears to play a key role in determining cell fate in vivo.

• Analytical Science and Technology
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• v.11 no.3
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• pp.179-188
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• 1998

The capacity factor of fifteen phenol derivatives was determined with respect to the concentration of ${\alpha}$- or ${\beta}$-cyclodextrin [CD], the type as well as the content of organic solvent in the mobile phase, and the temperature. The effect of the inclusion complex formation between solutes and ${\alpha}$- or ${\beta}$-cyclodextrin on their retention and selectivity has been investigated. The inclusion effect of ${\beta}$-cyclodextrin was the most effective in aqueous methanol, whereas only a poor effect was observed in aqueous tetrahydrofuran and aqueous acetonitrile. A plot of the reciprocal of the capacity factor against $[CD]_T$ gives a straight line and the dissociation constant, $K_D$ of the inclusion complex can be calculated from the slope. It was possible to estimate the $k_D$ values in 100% water from a linear plot of $pK_D$ vs. water content in the solution by extrapolation. The separation factor, ${\alpha}$, of two compounds has been found to be affected not only by the $[CD]_T$ but also by their $K_D$ values. Under optimum conditions, some mixtures of phenol derivatives were able to separate successfully.

• Korean Journal of Environmental Biology
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• v.27 no.1
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• pp.58-65
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• 2009

The chemopreventive effects of naringenin derived from citrus on tumor migration and the possible mechanisms involved in this protection were investigated in HT-1080 tumor cells. In this study, we found that naringenin reduced phorbol 12-myristate 13-acetate (PMA)-enhanced matrix metalloproteinases (MMP)-9 activation in a dose-dependant manner and further inhibited HT-1080 cell migration. In addition, naringenin suppressed PMA-enhanced expression of MMP-9 protein, mRNA and transcription activity levels through suppression of nuclear factor $\kappa$B (NF-$\kappa$B) activation and activator protein-1 (AP-1) translocation without changing tissue inhibitor of metalloproteinase (TIMP)-1 level. Therefore, our results suggested that the inhibitory effects of naringenin on MMP-9 activation, relation of tumor migration in vitro possibly involve mechanisms related to its ability to suppress PMA-enhanced MMP-9 gene and protein expression through NF-$\kappa$B activation and AP-1 translocation. Overall, naringenin may be a valuable anti-invasive drug candidate for cancer therapy.

• Journal of Chest Surgery
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• v.40 no.4 s.273
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• pp.264-272
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• 2007

Background: Vascular endothelial growth factor (VEGF) plays an important role in angiogenesis, including stimulating the proliferation and migration of vascular smooth muscle cells (VSMCs). It has been known that diabetes is associated with accelerated cellular proliferation via VEGF, as compared to that under a normal glucose concentration. We investigated the effects of selective blockade of a VEGF receptor by using anti-Flt-1 peptide on the formation and hyperplasia of the neointima in balloon injured-carotid arteries of OLETF rats and also on the in vitro VSMCS' migration under high glucose conditions. Material and Method: The balloon-injury method was employed to induce neointima formation by VEGF. For f4 days beginning 2 days before the ballon injury, placebo or vascular endothelial growth factor receptor-1 (VEGFR-1) specific peptide (anti-Flt-1 peptide), was injected at a dose of 0.5mg/kg daily into the OLETF rats. At 14 days after balloon injury, the neointimal proliferation and vascular luminal stenosis were measured, and cellular proliferation was assessed by counting the proliferative cell nuclear antigen (PCNA) stained cells. To analyze the effect of VEGF and anti-Flt-1 peptide on the migration of VSMCs under a high glucose condition, transwell assay with a matrigel filter was performed. And finally, to determine the underlying mechanism of the effect of anti-Flt-1 peptide on the VEGF-induced VSMC migration in vitro, the expression of matrix metalloproteinase (MMP) was observed by performing reverse transcription-polymerase chain reaction (RT-PCR). Result: Both the neointimal area and luminal stenosis associated with neointimal proliferation were significantly decreased in the anti-Flt-1 peptide injected rats, ($0.15{\pm}0.04 mm^2$ and $ 36.03{\pm}3.78%$ compared to $0.24{\pm}0.03mm^2\;and\;61.85{\pm}5.11%$, respectively, in the placebo-injected rats (p<0.01, respectively). The ratio of PCNA(+) cells to the entire neointimal cells was also significantly decreased from $52.82{\pm}4.20%\;to\;38.11{\pm}6.89%$, by the injected anti-Flt-1 peptide (p<0.05). On the VSMC migration assay, anti-Flt-1 peptide significantly reduced the VEGF-induced VMSC migration by about 40% (p<0.01). Consistent with the effect of anti-Flt-1 peptide on VSMC migration, it also obviously attenuated the induction of the MMP-3 and MMP-9 mRNA expressions via VEGF in the VSMCS. Conclusion: Anti-Flt-1 peptide inhibits the formation and hyperplasia of the neointima in a balloon-injured carotid artery model of OLETF rats. Anti-Flt-1 peptide also inhibits the VSMCs' migration and the expressions of MMP-3 and MMP-9 mRNA induced by VEGF under a high glucose condition. Therefore, these results suggest that specific blockade of VEGFR-1 by anti-Flt-1 peptide may have therapeutic potential against the arterial stenosis of diabetes mellitus patients or that occurring under a high glucose condition.