• 핵의학기술
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• 제13권1호
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• pp.15-19
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• 2009

Purpose: The aim of study is to find a correlation between Salivary clearance rate using saliva and blood and Secretion rate and Excretion rate using Salivary gland Scan images. Materials and Methods: Salivary Scan and Stimulate clearance of $^{99m}Tc$-pertechnate was performed in 20 patients with moderate function(group 1), 9 patients with severe function glands (group 2), 3 patients with non function (group 3) and normal 6 controls. Salivay clearance rate was compare with Secretion rate and Excretion rate of Salivary glands' ROI. Result: Stimulate salivary clearance of normal controls was 18.4 ml/min, salivary clearance of group 1 was 10.1 ml/min, salivary clearance of group 2 was 10.4 ml/min and salivary clearance of group 3 was 2.3 ml/min. Significant difference was found between normal controls and group 2,3 (p<0.05, p<0.05). Secretion rate and Excretion rate of normal controls was 21.6%, 24.6%, Secretion rate and Excretion rate of group 1 was 17.6%, 24.0%, Secretion rate and Excretion rate of group 2 was 8.8%, 13.9% and Secretion rate and Excretion rate of group 3 was 5.6%, 2.9%. Significant difference was found between normal controls and group 2,3 (p<0.05, p<0.05). Conclusions: Stimulate salivary clearance using saliva and blood and Secretion rate and Excretion rate using Salivary gland Scan images accord well together.

• 환경생물
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• 제30권4호
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• pp.349-354
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• 2012

To evaluate the biological response of sea squirt Halocynthia roretzi with different body size to heavy metals and its suitability for ecotoxicity assays, the effects of Cr, Cu and Zn on its clearance and oxygen consumption rates were investigated. Clearance and oxygen consumption rates of H. roretzi with various body sizes were calculated at different metal concentrations. Both clearance and oxygen consumption rate were negatively correlated with body sizes. Clearance rate of H. roretzi decreased gradually with increasing concentration of heavy metal, the decreasing rate was in an order of Cr>Cu>Zn. The oxygen consumption rate first increased at low metal concentration (below $100{\mu}g\;L^{-1}$) and then decreased rapidly with increasing metal concentrations. The decreasing rate was in an order of Cu>Cr=Zn. There was a trend that the clearance rate and oxygen consumption rate decreased drastically under a concentration of $400{\mu}g\;L^{-1}$, and then decreased smoothly when the metal ion concentration increased continually. So the oxygen consumption and clearance rate at a concentration of $400{\mu}g\;L^{-1}$ Cu could be thought as a suitable biological tool for exotoxicology analysis.

• The Korean Journal of Physiology
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• 제11권1호
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• pp.37-44
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• 1977

In the previous study of the release, excretion, and plasma concentration of aldosterone in normal Koreans, the author found that urinary aldosterone excretion and aldosterone secretion rate of the Korean who usually take high amount of salt are significantly lower, in compared to Americans, although the plasma concentration is only tended to be low. The control of plasma aldosterone level depends on the secretion rate and the metabolic clearance of the hormone. In this experiments, the metabolic clearance rate of aldosterone was determined in normotensive korean and the effects of adrenal stimulations on the rates were also studied in the same subjects. The metabolic clearance rate of the normal Korean was not significantly different from those of the American, and shown a little increase in response to sodium restriction. These results indicate that the decrease in secretion rate rather than the increase in metabolic clearance Tate is the major factor maintaining lower plasma aldosterone level. After furosemide diuresis, on the contrary, the removal of aldosterone showed significant the decrease despite slight increase of secretion rate. This suggest that the reduction in metabolic clearance rate of the hormone during volume depletion found to be major cause of high plasma concentration. Additional potassium supply produced detectable decrease of metabolic clearance rate, but the changes were smaller than that of secretion rate, which suggested that the higher secretion rate could account for elevated plasma concentration of aldosterone rather than metabolic clearance. Above results also support author's previous evidences that the normal Korean who already adapted to a high sodium diet have ability to produce adequate aldosterone activity without producing detectable changes on the metabolic clearance rate under the condition of sodium restriction with approp riate potassium intake.

• 한국패류학회지
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• 제17권2호
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• pp.95-104
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• 2001

To determine optimal conditions for measurement of the clearance rate in feeding experiment of an intertidal bivalve Glauconome chinensis, effects of starvation, extent of mixing at subsampling, and initial prey concentration were assessed. Experiments were conducted separately for each condition with different treatments. Two-way ANOVAs showed that there were significant differences in clearance rates among different starvation periods (p<0.001), extents of mixing (p = 0.005), and prey concentrations (p < 0.001). Starvation for 1 or 2 days gave rise to 2 to 3-fold increase in the clearance rate. After starvation for 5 days, the clearance rate decreased seriously, implying loss of physiological status. It is suggested that animals should be fed during acclimation. The differences of the clearance rates between gentle and vigorous mixings were significant, but the differences were smaller than that among different incubation times. It was found that vigorous mixing is not necessary. The effect of initial prey concentration was great. However, optimal prey concentration could not be determined at any fixed value. Experiments with multiple concentrations of algal prey are recommended. Optimal incubation time for measurement of the clearance rate of G. chinensis was determined to be 2-4 hours.

• 현장농수산연구지
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• 제14권1호
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• pp.107-115
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• 2012

치패 크기별 실험에서는 5mm치패의 여수율과 먹이섭취률은 각각 4.1 mL/h, 246×10⁴세포/h였으며, 15mm치패의 경우는 각각 70.8 mL/h, 4245.0×10⁴세포/h로서 치패 크기가 클수록 증가하였다. 회분외 건중량(AFDW)당 여수율 및 먹이섭취률은 7.5mm 치패에서 각각 3.3 mL/mg AFDW/h, 196.0×10⁴세포/mg AFDW/h로서 가장 높았다. 수온별 실험에서 10℃에서 여수율과 먹이섭취률은 각각 0.3×10⁴세포/h였고, 25℃에서는 각각 16.6 mL/h, 993.4×10⁴세포/h로서 25℃까지는 온도가 높을수록 여수율과 먹이섭취률이 증가하였으나, 30℃에서는 각각 12.9 mL/h, 772.6±298.6×10⁴세포/h로서 25℃보다 낮았다. 먹이생물 농도에 따라서는 여수율은 30×10⁴세포/mL일때는 21.1 mL/h였고, 농도가 240×10⁴세포/mL일 때는 2.3 mL/h로서 농도가 낮을수록 증가하였다. 먹이섭취률은 먹이생물의 농도가 60×10⁴세포/m일때 876.2×10⁴세포/h로서 최대값을 나타내었다.

• International Journal of Fluid Machinery and Systems
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• 제2권3호
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• pp.189-196
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• 2009

The effect of inlet and outlet blade angles on a micro regenerative pump head was examined in experiments. The pump head was little increased by changing the blade angles compared with the original pump with the inlet and outlet blade angles of 0 degree. The effect of the axial clearance between the impeller and the casing on the pump head was also examined. The head was increased largely by decreasing the axial clearance. The computation of the internal flow was performed to clarify the cause of the increase of the pump head due to the decrease of the clearance. The local flow rate in the casing decreased as the leakage flow rate through the axial clearance decreased due to the decrease of the clearance. It was found that the larger head in the smaller clearance was just caused by the smaller local flow rate in the casing. In the case of the smaller clearance, the smaller local flow rate caused the smaller circumferential velocity near the front and rear sides of the impeller. This caused the increase of the angular momentum in the casing and the head.

• 한국해양학회지:바다
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• 제18권2호
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• pp.80-88
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• 2013

본 연구에서는 두 개의 크기집단의 바지락(Ruditapes philippinarum), 재첩(Corbicula japonica), 홍합(Mytilus edulis)을 세 개의 수온 조건(5, 13 그리고 $18^{\circ}C$)에서 용존 노닐페놀에 노출시킴으로써 개체 크기와 수온 변화가 여수율과 용존 노닐페놀 흡수율에 미치는 영향을 조사하였다. 이를 통해 이매패류의 여수율과 유기화합물질 흡수과정의 관련성에 대해 평가하고자 하였다. 단위무게당 여수율($CR_{wt}$)은 모든 개체 크기와 온도 범위에서 홍합(0.3-4.9 L $g^{-1}\;h^{-1}$)이 가장 높았으며, 재첩(0.44-1.98 L $g^{-1}\;h^{-1}$), 바지락(0.08-0.6 L $g^{-1}\;h^{-1}$) 순으로 나타났다. 한편 단위무게당 노닐페놀의 흡수율은 종 간 뚜렷한 차이를 보이지 않았다. 단위무게당 여수율과 노닐페놀 흡수율은 일반적으로 개체의 크기가 증가함에 따라 감소하고, 온도가 증가함에 따라 증가하는 경향을 보였다. 세 종 모두에서 노닐페놀 흡수율은 여수율과 높은 상관관계를 보였다. 한편 노닐페놀 흡수율은 같은 여수율 범위에서 홍합, 재첩, 바지락 순으로 증가하였다. 여수율과 노닐페놀 흡수율의 높은 상관관계로부터 여수율이 이매패류의 용존 유기화합물 흡수에 중요한 역할을 한다는 것을 추정할 수 있다.

• Tribology and Lubricants
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• 제39권4호
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• pp.123-132
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• 2023

In this study, the expansion, stress, and operating clearance of bearing elements during operation are observed using the inner/outer ring temperature test data of a 3.0×10⁶ DN-class roller bearing. The operating clearance characteristics of inner-/outer-ring cooling (IORC) bearings are compared to those of inner-ring cooling (IRC) bearings. For IRC bearings, the thermal expansion of the outer ring is the most important factor in clearance variation. As a result, the operating clearance is less than the initial clearance of 61 ㎛, and the operating clearance decreases to 0.5 ㎛ at 25,500 rpm. Conversely, the temperature of the outer ring of IORC bearings is lower than that of IRC bearings, so the operating clearance is kept smaller. When the coolant flow rate to the outer ring is approximately 1.5 to 2.0 L/min, the temperature difference between the inner and outer rings is minimized and the operating clearance is maintained at a significantly lower level than IRC bearings. Small operating clearances are expected to be effective in reducing cage slip and skid damage in roller bearings. The results and analysis procedures of this study can be utilized to design of bearing clearance, lubricant flow rate, and assembled interference in the early design stage of aerospace roller bearings.

• 한국유체기계학회 논문집
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• 제11권6호
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• pp.7-17
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• 2008

Fan performances are obtained with various tip clearance gaps and stagger angles of the rotor. A tested fan is an axial-type fan of which the casing diameter is 806 mm. Two different rotors are applied to this test. One is designed on the basis of the free vortex method along the radial direction and the other is designed using the forced vortex method. The operating conditions are varied to the ultimate off-design point as well as the deign point. Overall efficiency, total pressure and input power are compared with the tip clearance gaps and different stagger angle. The experimental results show that changing of the stagger angle has minor influence to the performance when the same rotor is applied. When the tip clearance gap is less than 5% of the rotor span, the overall efficiency, total pressure loss and input power reduction are varied linearly with the variation of the tip clearance gaps. On the design point, the overall efficiency is decreased to the rate of 2.8-2.9 to the increasing of the tip clearance, but the changing rate of the overall efficiency is alleviated when the fan operates at off-design points. In particular, this rate is more quickly declined on a fan with the rotor designed using the forced vortex method. The result of the total pressure shows that the pressure reduction rate is a 0.08-0.1 according to the tip clearance, and additionally the input power reduction rate is a 0.045-0.065 at design point.

• Journal of Ecology and Environment
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• 제37권4호
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• pp.225-229
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• 2014

Feeding behavior of Temora turbinata was investigated through laboratory experiments with special emphasis on its food preference and consequent clearance rate on diatom and microbial components given as common natural food assemblage of coastal area (Uchiumi, Uwa Sea, Japan). Among available prey items, T. turbinata showed the highest clearance rate for Thalassiosira spp. ($0.23{\pm}0.08L\;Temora^{-1}day^{-1}$) followed by Chaetoceros spp. ($0.11{\pm}0.03L\;Temora^{-1}day^{-1}$), but clearance rates for other diatom, Nitzschia spp. was lower (0.03 to $0.07L\;Temora^{-1}day^{-1}$). Bacterial abundances showed no response against 24-h feeding of T. turbinata. Feeding of T. turbinata on heterotrophic nanoflagellates (HNF) was apparent when clearance rates of T. turbinata on diatoms were relatively low, but T. turbinata did not consume HNF as well as ciliates with Thalassiosira spp. of which clearance rate was highest. The results suggest that HNF and ciliates are possible supplementary prey item for T. turbinata, but their contribution as food sources can be limited by the presence of other prey items such as preferable diatom species.