• Title/Summary/Keyword: Cell size

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Measurement of effective thermal conductivity and permeability on aluminum foam metal (알루미늄 발포금속의 유효열전도도와 침투율의 측정)

  • 백진욱;강병하;김서영;현재민
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.11 no.2
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    • pp.185-192
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    • 1999
  • Effective thermal conductivities and pressure-drop-related properties of aluminum foam metals have been measured. The effects of porosity and cell size in the aluminum foam metal are investigated in detail. The porosity of the foam metal, considered in the present study, varies from 0.89 to 0.96 and the cell size from 0.65㎜ to 2.5㎜. The effective thermal conductivity is evaluated by comparing the temperature gradient of the foam metal with that of the thermal conductivity-known material. The pressure drop in the foam metal is measured by a highly precise electric manometer while air is flowing through the aluminum foam metal in the channel. The results obtained indicate that the effective thermal conductivities are found to be increased with a decrease in the porosity while the effective thermal conductivities ire little affected by the cell size at a fixed porosity. However, the pressure drop is strongly affected by the cell size as well as the porosity. It is seen that the pressure drop is increased as the cell size becomes smaller, as expected. The minimum pressure drop is obtained in the porosity 0.94 at a fixed cell size. A new correlation of the pressure drop is proposed based on the permeability and Ergun's coefficient for the aluminum foam metal.

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Effect of Inoculum Size on Biomass Accumulation and Ginsenoside Production by Large-Scale Cell Suspension Cultures of Panax ginseng

  • Thanh Nguyen Trung;Murthy Hosakatte Niranjana;Yu Kee-Won;Jeong Cheol Seung;Hahn Eun-Joo;Paek Kee-Yoeup
    • Journal of Plant Biotechnology
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    • v.6 no.4
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    • pp.265-268
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    • 2004
  • Cell growth and ginseng saponin production by large-scale suspension (bioreactor) cultures of Panax ginseng were investigated under various inoculum sizes. Cell growth was low at an inoculum size of 40 g FW/L, and the maximum cell growth was obtained with increasing inoculum size up to 100 g FW/L. The cell density of 333 g FW/L and 12.7 g DW/L was obtained at inoculum size of 100 g FW/L after 30 days of cultivation. Maximum saponin production of $4.40\;\cal{mg/g}$ DW was achieved at 60 g FW/L of inoculum size. Thus, inoculum size 60 g FW/L was suitable for optimum biomass accumulation as well as saponin production during bioreactor cultivation of ginseng suspension cells.

Comparison of Some Tissues in Diploid and Triploid Hybrid between Mud Loach, Misgurnus mizolepis and Cyprinid Loach, M. anguillicaudatus (미꾸라지, Misgurnus mizolepis와 미꾸리, M. anguillicaudatus간 잡종 및 잡종 3배체 일부 조직에서의 세포 및 핵 크기)

  • 박인석;김동수
    • Development and Reproduction
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    • v.4 no.1
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    • pp.19-28
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    • 2000
  • Diploid and triploid hybrid between female mud loach Misgurnus mizolepis and male cyprinid loach, M. andguillicaudatus were produced, using artificial propagation. The influence of hybridization and triploidization on characteristics of the some tissues of retina optic tectum and trunk kidney in loach was determined histologically. Diploid hybrid have almost size similarities in nucleus and the cell size of some tissues to both parents. In the triploid hybrid the nucleus and/or the cell size in erythrocyte, horizontal cell in inner nuclear layer of retina ganglion cell in ganglion cell layer of retina, neuronal cell in granular layer of optic tectum, and secondary proximal tubule cell of trunk kidney, are much larger than those of the corresponding cells in the diploid hybrid individuals. However, triploid hybrid showed fewer number of cells in outer nuclear layer in retina and nuclei in secondary proximal tubule of trunk kidney than in diploid hybrid. Results of this study suggest that some characteristics in the triploid hybrid exhibiting larger cell and nucleus size with fewer number of cell than diploid hybrid can be useful criteria for the distinction between diploid hybrid and triploid hybrid, and the ploidy level in loach.

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Flow Cytometric Analysis of Bovine Granulosa Cells : Changes of Cell Cycle During Follicular Maturation (Flow Cytometer를 이용한 소 과립막세포의 분석 : 난포성숙에 따른 세포주기의 변화)

  • 김해정;김동훈;이훈택;정길생
    • Korean Journal of Animal Reproduction
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    • v.17 no.4
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    • pp.279-285
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    • 1994
  • The objective of the present study was to characterize the cell cycles of granulosa cell populations during follicular maturation in cattle by using flow cytometer. Granulosa cells were isolated from bovine preovulatory antral follicles of F1(>10mm), F2(5~20mm), F3(3~4mm) and F4(1~2mm) diameter and fixed and stained with fluorochromes that selectively bine to DNA. Flow cytometer equipped with a laser excitation system was used to analyze the intensity of fluorescence from stained cells. Forward angle light-scatter(FSC) and 90$^{\circ}$light-scatter(SSC) signals were adopted to measure the size and the granularity of granulosa cells. As a results of FSC/SSC analysis, granulosa cell populations(G1 phase of cell cycle) from each follicle were relatively regular in size and granularity, regardless of follicular size. However, their distribution in granularity was greater than that in size. Most of granulosa cell populations collected from each follicle were distributed in G0/G1, S and G2/M phases. As the follicles approached to ovulation the percentage of cells in the proliferative phases of cell cycle (S and G2/M) decreased significantly, but there was a concomitant increase in the percentage of granulosa cells in G1 phase. Therefore, these data indicate the proportion of main populations to cell cycle of granulosa cells may be changed from proliferative phase to G1 phase during follicular maturation in cattle.

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Preparation and Characterization of Polypropylene/Waste Ground Rubber Tire Powder Microcellular Composites by Supercritical Carbon Dioxide

  • Zhang, Zhen Xiu;Lee, Sung-Hyo;Kim, Jin-Kuk;Zhang, Shu Ling;Xin, Zhen Xiang
    • Macromolecular Research
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    • v.16 no.5
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    • pp.404-410
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    • 2008
  • In order to obtain 'value added products' from polypropylene (PP)/waste ground rubber tire powder (WGRT) composites, PP/WGRT microcellular foams were prepared via supercritical carbon dioxide. The effects of blend composition and processing condition on the cell size, cell density and relative density of PP/WGRT micro-cellular composites were studied. The results indicated that the microcellular structure was dependent on blend composition and processing condition. An increased content of waste ground rubber tire powder (WGRT) and maleic anhydride-grafted styrene-ethylene-butylene-styrene (SEBS-g-MA) reduced the cell size, and raised the cell density and relative density, whereas a higher saturation pressure increased the cell size, and reduced the cell density and relative density. With increasing saturation temperature, the cell size increased and the relative density decreased, whereas the cell density initially increased and then decreased.

Standardized Uptake Values Highly Correlate with Tumor Size and Fuhrman Grade in Patients with Clear Cell Renal Cell Carcinoma

  • Polat, Emre Can;Otunctemur, Alper;Ozbek, Emin;Besiroglu, Huseyin;Dursun, Murat;Ozer, Kutan;Horsanali, Mustafa Ozan
    • Asian Pacific Journal of Cancer Prevention
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    • v.15 no.18
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    • pp.7821-7824
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    • 2014
  • Background: We investigated the correlation between standardized uptake value (SUVmax), tumor size and Fuhrman grade in patients with renal cell carcinoma (RC). Materials and Methods: We retrospectively analyzed the data of 54 patients with clear cell renal cell carcinoma histopathologically diagnosed who underwent fluorine-18 fluoro-2 deoxyglucose positron emission tomography/computed tomography (F-18 FDG PET/CT) between January 2005 and March 2014. Results: Avarage tumor sizes were $5.64{\pm}1.85$, $6.85{\pm}2.24$ and $7.98{\pm}2.45$ in low, medium and high SUVmax groups, respectively. The Spearman's correlation coefficient between the tumor size and SUVmax was 0.385 (p=0.004) and between the Fuhrman grade and SUVmax was 0.578 (p<0.001). Conclusions: SUVmax appears highly correlated with tumor size and Fuhrman grade in patients with histopathologically confirmed clear cell RC. Multicenter studies are needed to provide larger series for more accurate results.

Effect of Rubber on Microcellular Structures from High Internal Phase Emulsion Polymerization

  • Park, Ji-Sun;Chun, Byoung-Chul;Lee, Seong-Jae
    • Macromolecular Research
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    • v.11 no.2
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    • pp.104-109
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    • 2003
  • A microcellular, which combines a rubber with the conventional formulation of styrene/divinylbenzene/sorbitan monooleate/water system, was prepared using high internal phase emulsion (HIPE) polymerization. Although the open microcellular foam with low density from the conventional HIPE polymerization shows highly porous characteristics with fine, regular and isotropic structure, the one having much smaller cell size is desirable for various applications. In this study, a polybutadiene was introduced to reduce the cell size with comparable properties. Major interests were focused on the effects of rubber concentration and agitation speed on the cell sizes and compression properties. Scanning electron microscopy was used to observe the microcellular morphology and compression tests were conducted to evaluate the stress-strain behaviors. It was found that the cell size decreased as rubber concentration increased, reflecting a competition between the higher viscosity of continuous phase and the lower viscosity ratio of dispersed to continuous phases due to the addition of high molecular weight rubber into the oil phase of emulsion. A correlation for the average cell size depending on agitation speed was attempted and the result was quite satisfactory.

Quality Characteristics of Korean Red Ginseng Powder with Different Milling Methods (분쇄방법에 따른 고려홍삼분말의 품질특성)

  • 서창훈;이종원;도재호;김나미;양재원;장규원
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.32 no.3
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    • pp.370-374
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    • 2003
  • Cell cracking method using a non-collision was evaluated for the possibility of new red ginseng grinding technique. Based on particle size distribution analysis by 1size shaker, the ratios of 100 mesh penetrated particles were 94.9% for hammer mill (group A) and 95.6% for cell crack (group B). The ratio of 120 mesh penetrated particle of group A was higher than that in group B. The particle size distributions for 100 mesh non-penetrated Powder between 2 groups were not significantly different, and particle size distribution analysis by laser scattering analyzer showed that the particle size ranges were 0.77~128.07 ${\mu}{\textrm}{m}$ for group A and 4.24~180.07 ${\mu}{\textrm}{m}$ for group B. The Particle size distribution in group A was more broad than that in group B. The mean particle size in group B was larger than that in group A, while the standard deviation of particle size distribution in group B was less than that in group A. Structural surface characteristics, in group A, particle size distribution was broad and the distribution curve was amorphous. The structure of individual particles was similar to unequal stone which was roughly grinded and had soft cotton-like surface. In the contrary, in group B, particle size distribution was relatively narrow and also individual size particles were ubiquitously distributed. The structure of individual particles was unequal cut stone shape.

Analysis of Three Dimensional Equal Chanel Angular Pressing by Using the Finite Element Method in Conjunction with the Dislocation Cell Based Constitutive Model (전위 셀 구성모델을 결합한 유한요소법을 이용한 3차원 등통로각압출 공정 해석)

  • Yoon, Seung Chae;Kim, Hyoung Seop
    • Korean Journal of Metals and Materials
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    • v.47 no.11
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    • pp.699-706
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    • 2009
  • Deformation behavior of pure aluminum during equal channel angular pressing (ECAP) was simulated using a three-dimensional version of the finite element method in conjunction with a constitutive model based on the dislocation density and cell evolution. The three-dimensional finite element analyses for the prediction of microstructural features, such as the variation of the dislocation density and the cell size with the number of ECAP, are reported. The calculated stress and strain and their distributions are also investigated for the route Bc ECAP processed pure aluminum. The results of finite element analyses are found to be in good agreement with experimental results for the dislocation cell size. Due to the accumulation of strain throughout the workpiece and an overall trend to saturation in cell size, a decrease of the difference in cell size with the number of passes (1~4) was predicted.

A Study on the Cell Resequence Method at the ATM Switch (공유 버퍼형 순서 재정렬 ATM스위치에 관한 연구)

  • 박성헌;전용일박광채
    • Proceedings of the IEEK Conference
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    • 1998.10a
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    • pp.273-276
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    • 1998
  • This paper proposes a new Asynchronous Transfer Mode(ATM) switch architecture for the Broadband ISDN. The proposed switch has the architecture to prohibit the out-of-sequence in shared buffer switch system with being fixed buffer size in the out-buffered large scale ATM Switch System. then in this paper proposes cell resequence algorithm to decrease the out-of-sequence problem. also, we studied the out-of-sequence problem that was occurred by the cell transfer delay and the cell overflow due to the fixed buffer size when cell resequenced and we propose to implement optimal ACFIFO(Address Counter First In First Out) buffer size which has the minimized cell loss.

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