• Geomechanics and Engineering
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• v.28 no.2
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• pp.107-116
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• 2022

The steady state of unsaturated soil takes a long time to achieve. The soil seepage behaviours and hydraulic properties depend highly on the wetting/drying rate. It is observed that the soil-water characteristic curve (SWCC) is dependent on the wetting/drying rate, which is known as the dynamic effect. The dynamic effect apparently influences the scanning curves and will substantially affect the seepage behavior. However, the previous models commonly ignore the dynamic effect and cannot quantitatively describe the hysteresis scanning loops under dynamic conditions. In this study, a dynamic hysteresis model for SWCC is proposed considering the dynamic change of contact angle and the moving of the contact line. The drying contact angle under dynamic condition is smaller than that under static condition, while the wetting contact angle under dynamic condition is larger than that under static condition. The dynamic contact angle is expressed as a function of the saturation rate according to the Laplace equation. The model is given by a differential equation, in which the slope of the scanning curve is related to the slope of the boundary curve by means of contact angle. Empirical models can simulate the boundary curves. Given the two boundary curves, the scanning curve can be well predicted. In this model, only two parameters are introduced to describe the dynamic effect. They can be easily obtained from the experiment, which facilitates the calibration of the model. The proposed model is verified by the experimental data recorded in the literature and is proved to be more convenient and effective.

• Biomedical Science Letters
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• v.29 no.4
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• pp.280-286
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• 2023

In humic substances, fulvic acid (FA) is a subclass of diverse compounds known as humic substances, which are by-products of organic degradation from microorganisms. FA can suppress the proliferation of tumor cells. Despite numerous studies, the exact mechanism for the various effects of FA is not clearly understood. Based on results demonstrating anti-proliferation effects on human cancer, we investigated whether FA has similar effects on lung cancer in this study. Firstly, the anti-cancer effect of FA in pulmonary epithelial tumor cell lines (TC-1 cells) was examined by confirming its inhibitory effect on the cell proliferation of TC-1 cells. TC-1 cell proliferation was reduced by FA on a dose-dependent and time-dependent manner. After 24 hours of FA treatment, cell morphological changes such as cell volume decrease, non-adherence and increased number of apoptotic cells were clearly observed. In addition, FA induced a DNA ladder pattern by increased of DNA fragments in TC-1 cells. In the intracellular regulatory pathway by FA, we confirmed that FA induced the reduction of the anti-apoptotic protein, Bcl-2 protein levels. These results indicate that FA has anticancer effect by inducing intracellular apoptotic pathway. Further research on the mechanism of anticancer effects will be basic data for the development of potential anticancer drugs.

• 한국해양학회지
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• v.24 no.4
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• pp.165-171
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• 1989

To examine the sample variability of zooplankton, samples were collected at two stations in the nearshore off Anhung (Chungnam, Korea), using a NORPAC net (76 Cm diameter, 0.333 mm mesh size) for two days, April 5 and 6, 1989. The net was towed vertically to eliminate the source of variation due to vertical migration. During the period of 6 hours, triplicate sampling was done every one or two hour at each station. Species composition and abundances at two stations were not so different, but the abundances at each station varied greatly with respect to sampling time. Greater abundance at one sampling time ranged 2.3-8.7 times of smaller abundance at another sampling time. At the level of ${\alpha}=0.05$, however, mean abundances of different sampling time did not differ significantly from each other due to the large variance. It was believed that the large variance was caused by the time dependent effect of patchiness of which parameters were varied with time because of sea water movement. From the variation within the triplicate samples, it was considered that the abundance data obtained from single tow were not significantly different from the data in the range of 50-200% of those from single tow. From these results, the necessity for the replicate and time dependent sampling was indicated. In the nearshore like the sampling site of this study, it seemed to be better to reduce the number of stations for the replicate and time dependent sampling though the proper sampling scheme was to be decided based on the goal of the study.

• Journal of Pharmaceutical Investigation
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• v.40 no.5
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• pp.297-304
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• 2010

The present work focuses on preparation of olanzapine, orally dispersing tablets by direct compression method. Effect of super disintegrant crospovidone, disintegration time, drug content on in vitro release has been studied. A factorial design was employed in formulating a prompt dispersible tablet. The selected independent variables crospovidone and fmelt showed significant effect on dependent variables i.e. disintegration time and percent drug dissolved. Disintegration time and percent drug dissolved decreased with increase in the level of crospovidone. The similarity factor $f_2$ was found to be 97.48 for the developed formulation indicating the release was similar to that of the marketed formulation. Pharmacokinetics of olanzapine after single-dose oral administration of orally disintegrating tablet in normal volunteers were evaluated and the results showed that PK parameters (Cmax, Tmax, AUC) of the designed ODT matrix were similar to those of commercial product, Zyprexa Zydis$^{(R)}$ as a reference.

• Proceedings of the Korean Society for Food Science of Animal Resources Conference
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• 2006.05a
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• pp.277-280
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• 2006

This study was carried out to investigate the effect of HPLT on the inactivation rates of microorganisms in raw milk depending on the pressurization time and temperature. Raw milk samples were submitted to HPLT of 200 MPa at -4, 4, 12 and $20^{\circ}C$, respectively. Inactivation increased with pressurization time and HPLT of microorganisms at 200 MPa was time dependent at any temperature. At sub-zero temperature of $-4^{\circ}C$, high pressure pasteurization was the most effective in inactivating microorganisms.

• Proceedings of the Korean Society for Food Science of Animal Resources Conference
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• 2006.05a
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• pp.329-332
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• 2006

This study was carried out to investigate the effect of high pressure low temperature (HPLT) on the inactivation rates of S. cerevisiae in 0.9% saline solution depending on the pressurization time and temperature. S. cerevisiae was inoculated with UHT milk and submitted to HPLT of 200 MPa at 4, 12 and $20^{\circ}C$, respectively Inactivation increased with pressurization time and HPLT of S. cerevisiae at 200 MPa was time dependent at any temperature. The morphological changes of yeast cells observed with a SEM after HPLT.

• Earthquakes and Structures
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• v.14 no.1
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• pp.33-44
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• 2018

Base-isolated nuclear power plant (BI-NPP) structures are founded on expanded basemat as a flexible floating nuclear island, are still lacking the recommendation of the consideration of incoherent motion effect. The effect of incoherent earthquake motion on the seismic response of BI-NPP structure has been investigated herein. The incoherency of the ground motions is applied by using an isotropic frequency-dependent spatial correlation function to perform the conditional simulation of the reference design spectrum compatible ground motion in time domain. Time history analysis of two structural models with 486 and 5 equivalent lead plug rubber bearing (LRB) base-isolators have been done under uniform excitation and multiple point excitation. two different cases have been considered: 1) Incoherent motion generated for soft soil and 2) Incoherent motion generated for hard rock soil. The results show that the incoherent motions reduce acceleration and the lateral displacement responses and the reduction is noticeable at soft soil site and higher frequencies.

• Proceedings of the Korean Statistical Society Conference
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• 2005.11a
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• pp.73-78
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• 2005

This paper considers a preventive maintenance policy following the expiration of renewing warranty, Most preventive maintenance models assume that each PM costs a fixed predetermined amount regardless of the effectiveness of each PM. However, it seems more reasonable to assume that the PM cost depends on the degree of effectiveness of the PM activity. In this paper we consider a periodic preventive maintenance policy following the expiration of renewing warranty when the PM cost is an increasing function of the PM effect. The optimal number and period for the periodic PM policy with effect dependent cost that minimize the expected cost rate per unit time over an infinite time span are obtained.

• Journal of Acupuncture Research
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• v.21 no.2
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• pp.167-181
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• 2004

Objective : Carthami Flos has been used as a herb to promote blood circulation to remove blood stasis in oriental medicine for many centuries. To investigate treatment of cerebral vascular disease(CVA) by promoting blood circulation and removing blood stasis(活血化瘀法), we observed the experimental Effects of Aqua-Acupuncture of Carthami Flos on the Regional Cerebral Blood Flow and Mean Arterial Blood Pressure in Rats. Method : When aqua-acupuncture of Carthami Flos(ACF) was injected into LI4, Liv3, B23, B62, GV16, experimental effects of ACF on the regional cerebral blood flow(rCBF) and mean arterial blood pressure(MABP) is not known. Therefor, this study was designed to investigate the effects of ACF on the change of cerebral hemodynamics. The changes of rCBF and MABP were tested by Laser Doppler Flowmetry(LDF). Results : When ACF was injected into LI4, change of rCBF and MABP were decreased in a injected time-dependent manner. When ACF was injected into Liv3, change of rCBF and MABP were decreased in a injected time-dependent manner. When ACF was injected into B23, change of rCBF was significantly increased in a injected time-dependent manner, MABP did not change. When ACF was injected into B62, change of rCBF was increased in a injected time-dependent manner, change of MABP was significantly decreased after injection 60min. When ACF was injected into GV16, change of rCBF and MABP were similar to the change of normal. Conclusions : In conclusion, I suggested that ACF(LI4, Liv3) has an effect that depress the blood pressure & cerebral hemodynamic acceleration and ACF(B23, B62) has an anti-ischemic effect through the improvement of crebral hemodynamics.

• Journal of The Korean Association For Science Education
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• v.21 no.5
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• pp.841-854
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• 2001

The purpose of this study was to find the effect of these variables on the duration of the momentum effect. To examine the momentum effect for gravitational field concepts, an intensive time series design was used. We collected data every day except Sundays and holidays for 50 days; 5 days for baseline, 30 days for intervention, and 15 days for the follow up We adopted cognitive levels and styles as students characteristics and two item characteristics(quantity versus quality, and word versus picture) as the item representation patterns. In this study, the momentum effect was influenced by students characteristics and item representation patterns. The results showed that two variables, cognitive style and quantity/quality, were the most influential factors for the duration of momentum effect. Field independent students showed a longer duration than field dependent students did. In addition, students showed a longer duration in quality items than in quantity items. However, students cognitive levels(formal or preformal) and word/picture presentations seemed to have relatively weak effect on the duration of the momentum effect.