• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.04a
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• pp.805-810
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• 1997

In this paper the technique to predict tool were theoretically in the sheet metal shearing process is suggested. The were in sheet metal tool affects the tolerances of final parts, metal flows and costs of processes. In order to predict the tool were the deformation of workpiece during the process is analyzed by using non-isothermal finite element program. The ductile fracture criterion and the element kill method are also used to estimate if and where a fracture will occur and to investigate the features of the sheared surface in shearing process. Results obtained form finite element simulation such as node velocities and node forces are transformed into sliding velocity and normal pressure on tool monitoring points respectively. The monitoring points are automatically generated and the were rates on these points are accumulated during a process. It is assumed that the wear depth on the tool surface are linear function of the lot sizes based upon the known experimental results. The influence of clearance between die and punch upon tool wear is were is also discussed during the process.

• YAKHAK HOEJI
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• v.36 no.1
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• pp.46-55
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• 1992

Methoxyverapamil, $Ca^{2+}$ channel blocker, when given intravenously by means of bolus, produced the transient increase of urine flow, and then methoxyverapamil was infused in this experiments. Methoxyverapamil, when infused into vein, elicited the increase of urine flow ancampanied with the increased glomeralar filtration rate(GFR), renal plasma flow(RPF), excretion amounts of sodium and potassium in urine($E_{Na},\;E_k$) and osmolar clearance(Cosm), wherease produced the no change of free water clearance($C_{H2O}$) and the reduction of reabsorption rates of sodium and potassium in reral tubules($R_{Na},\;R_k$). Methoxyverapamil, when infused into a renal artery, exhibited the diuretic action in only infused Kidney, at this time changes of renal function were the same aspect to that of intravenously infused methoxyverapamil. Methoxyverapamil, when infused into a carotid artery, exhibited the decreased urine flow along with the reduction of Cosm, $C_{H2O}\;and\;E_{Na}$. Above results suggest that methoxyverapamil possess both the diuretic action by direct action in kidney and antidiuretic action through the central function.

• The Korean Journal of Malacology
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• v.21 no.1
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• pp.47-56
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• 2005

A series of radiotracer experiments were employed to quantitatively compare the biokinetics of uptake from the dissolved phase (influx rates), uptake from the various types of food source (assimilation efficiency), and loss (efflux) of Ag between Potamocorbula amurensis and Macoma balthica. Simultaneously, influx rates of dissolved Cd in both clams were determined to compare with those of Ag. Effects of salinity on influx rates were evaluated in these 2 euryhaline species, as were effects of clam size. Influx rate of Ag and Cd (${\mu}g g^{-1}$ [dry wt.] $d^{-1}$) increased linearly with metal concentrations. Influx rates of Ag in both clams were 3 to 4 times those of Cd. Absolute influx rates of the 2 metals were 4 to 5 times greater in P. amurensis than M. balthica, probably because of differences in biological attributes (i.e. clearance rate or gill surface area). As salinity was reduced from 20 to 2.5 psu, the influx rate of Cd in P. amurensis increased 4-fold and that of Ag increased 6-fold, consistent with expected changes in speciation. Weight-specific metal influx rates (${\mu}g g^{-1}$ [dry wt.] $d^{-1}$) were negatively correlated with the tissue dry weight of the clams, but most rate constants determining physiological turnover of assimilated metals were not affected by clam size.

• Korean Journal of Ecology and Environment
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• v.39 no.3 s.117
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• pp.390-401
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• 2006

This study was conducted to understand the phytoplankton-zooplankton trophic linkage in Lake Paldang ecosystems (Paldang Dam and Kyungan Stream) from April to December 2005. Zooplankton were filtered as two size groups (microzooplankton (MICZ): 60{\sim}20\;{\mu}m$, macrozooplankton (MACZ): >$200\;{\mu}m$), and their clearance rates and C-fluxes on phytoplankton were measured. Grazing experiments were performed in the laboratory with the different zooplankton densities (0, 2, 4, 8x of ambient density, n=2). Diatoms, such as Aulacoseira and Cyclotella were dominant phytoplankton taxa at both sites. Among phytoplankton communities, total carbon biomass of phyflagellates was much higher than others at both sites. Rotifers numerically dominated zooplankton community, while cladocerans dominated carbon biomass. Both phytoplankton and zooplankton density and biomass were high in spring, but decreased markedly after summer monsoon season. plankton biomass at Kyungan Stream was significantly higher than that of Paldang Dam. Zooplankton clearance rate and amount of C-flux were relatively high in the spring and then decreased after summer at both sites. Seasonal change of C-flux was similar to that of zooplankton biomass (P<0.001, n=7). MACZ clearance rate and C-flux were higher than those of MICZ. Water residence time and physical disturbance in summer appeared to affect zooplankton grazing on phytoplankton at the study sites. Our results indicate phytoplankton were an important energy source for zooplankton in Lake Paldang ecosystem. Furthermore, C-flux of plankton food web is affected by not only biological components but also physical parameters.

• Asian-Australasian Journal of Animal Sciences
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• v.29 no.8
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• pp.1102-1110
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• 2016

The mammalian target of rapamycin (mTOR) regulates cellular processes such as cell growth, metabolism, transcription, translation, and autophagy. Rapamycin is a selective inhibitor of mTOR, and induces autophagy in various systems. Autophagy contributes to clearance and recycling of macromolecules and organelles in response to stress. We previously reported that vitrified-warmed mouse oocytes show acute increases in autophagy during warming, and suggested that it is a natural response to cold stress. In this follow-up study, we examined whether the modulation of autophagy influences survival, fertilization, and developmental rates of vitrified-warmed mouse oocytes. We used rapamycin to enhance autophagy in metaphase II (MII) oocytes before and after vitrification. The oocytes were then subjected to in vitro fertilization (IVF). The fertilization and developmental rates of vitrified-warmed oocytes after rapamycin treatment were significantly lower than those for control groups. Modulation of autophagy with rapamycin treatment shows that rapamycin-induced autophagy exerts a negative influence on fertilization and development of vitrified-warmed oocytes.

• Journal of Biosystems Engineering
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• v.27 no.6
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• pp.547-556
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• 2002

Upright positioning of garlic cloves in mechanical planting has been considered as an essential process because pose of garlic affects not only initial budding and rooting of garlics but quality and yield. Due to the geometrical uniqueness and irregularity of garlic cloves in shape, manual planting operation has been conducted. The overall objective of this research was to determine design factors for designing a garlic clove planter The results are summarized as follows : 1. A vibrating-type clove-metering device was designed and tested. Effects of tilted angle of metering plate and magnitude of vibration on metering performance were investigated. The successful planting rates of the metering device were 96.7% for Hanji varieties. 2. Clove upright-positioning device, posture inducer was designed and tested. When the clearance between the hoppers was set at 4mm, the rates of upright positioning of the device were 92.2% for with Hanji varieties. 3. Optimum metering performance was observed at the plate tilted angle of 80。 with the posture type positioning device.

• Biomolecules & Therapeutics
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• v.7 no.3
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• pp.249-256
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• 1999

Glibenclamide(GLY)(1.0 and 3.0 mg/kg), an ATP-dependent $K^+$ channel blocker, when given into the vein in dogs, produced the diuretic action accompanied with the increase of osmolar clearance($C_{osm}$), urinary excretion of $Na^+$ and $K^+$ ($E_{Na}$, $E_K$), and with the decrease in reabsorption rates for $Na^+$ and $K^+$ in renal tubules ($R_{Na}$, $R_K$), and then ratios of $K^+$ against $Na^+$($K^+$/$Na^+$) were decreased. GLY did not affect mean arterial pressure at any doses used. At a low dose(0.1 mg/kg), GLY injected into a renal artery brought about the diurectic action in both experimental and control kidney, however at a higher dose(0.3 mg/kg), GLY appeared significant diuretic action in the control kidney, but not in experimental kidney and the decrease of glomerular filtration rates(GFR), renal plasma flow(RPF), $E_K$, and the increase in $E_{Na}$. In the control kidney, these changes in renal function exhibited the same aspect as shown in intravenous experiments. In experiments given into carotid artery of GLY(0.5 and 1.5 mg/kg), changes in all renal function included the increase in urine volume were the same pattern as shown in intravenous experiments. The above results suggest that glibenclamide produces diuretic action through central function and the action site of the GLY in kidney is the renal distal tubules in dogs.

• Biomedical Science Letters
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• v.25 no.1
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• pp.32-39
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• 2019

Conventional high-flux hemodialysis (HD) is not as good as normal kidney function. Morbidity and mortality rates of patients receiving HD are still very high. To increase mid-to-large molecule clearance by combining diffusion and convection, on-line hemodiafiltration (HDF) is required. The objective of this study was to compare long-term survival rate of patients treated with on-line HDF to those who received conventional high-flux HD by reviewing data from Chonnam National University Hospital (CNUH). We selected patients who attended the 'CUNH dialysis center' and agreed to participate in the study. Overall, 40 patients with ESRD switched from high flux HD to on-line HDF or started on-line HDF from August 2007 to December 2009. Additionally, a total of 42 patients receiving conventional high-flux HD during the same period were enrolled. We then reviewed long-term survival rate of patients receiving on-line HDF over the next seven years. When we compared survival rates for seven years, the survival rate of the group receiving on-line HDF was 65% (26/40) while that of the group receiving the conventional high-flux HD was 54.8% (23/42). Although the number of patients was small to see survival difference clearly by one specific dialysis modality, there was somewhat difference in survival rate between the two groups. Indicators such as anemia, calcium-phosphate metabolism, nutritional status, treatment adequacy, and hospitalization were also improved in the group receiving HDF. Overall, results of our study showed beneficial effects of on-line HDF on clinical outcomes and survival in chronic HD patients.

• Journal of Advanced Marine Engineering and Technology
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• v.25 no.1
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• pp.182-190
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• 2001

The aerodynamics of the Wells turbine has been studied using 3-d, unstructured mesh flow solver for the Reynolds-averaged Navier-Stokes equations. The basic feature of the Wells turbine is that even though the cyclic airflow produces oscillating axial forces on the airfoil blades, the tangential force on the rotor is always in the same direction. Geometry used to define 3-D numerical grid is based upon that of an experimental test rig. The 3-D Wells turbine model, consisting of approximate 220,000 cells is tested of four axial flow rates. In the calculations the angle of attack has been varied between 10˚ and 30˚ of blades, Representative results from each case are presented graphically andy analysed. It is concluded that this technique holds much promise for future development of Wells turbines.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.12 no.1
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• pp.78-83
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• 2003

Electro-rheological(ER) fluids are suspensions in which rheological properties show an abrupt change with variation of electric fields. We modeled the parallel-plates relating to ER-Valve system and yielded shear stress according to the strength of electric field. The purpose of the present study is to examine the flow characteristics of ER fluids according to the strength of electric field between parallel-plates. Then the steady relationship between pressure drop and flow rate of the ER fluids between parallel-plates under application of an electric fields was measured. The pressure drop and flow rates of ER fluids under the application of electric fields for steady flow were measured. For the experiment, we used the ER fluids, 35w% zeolite having hydrous particles and differential pressure gauge. This test reviewed experiment for the special changes of ER fluids in the steady flow condition.