• Korean Journal of Materials Research
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• v.27 no.12
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• pp.664-671
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• 2017

A composite material was prepared for the bipolar plates of phosphoric acid fuel cells(PAFC) by hot pressing a flake type natural graphite powder as a filler material and a fluorine resin as a binder. Average particle sizes of the powders were 610.3, 401.6, 99.5, and $37.7{\mu}m$. The density of the composite increased from 2.25 to $2.72g/cm^3$ as the graphite size increased from 37.7 to $610.3{\mu}m$. The anisotropy ratio of the composite increased from 1.8 to 490.9 as the graphite size increased. The flexural strength of the composite decreased from 15.60 to 8.94MPa as the graphite size increased. The porosity and the resistivity of the composite showed the same tendencies, and decreased as the graphite size increased. The lowest resistivity and porosity of the composite were $1.99{\times}10^{-3}{\Omega}cm$ and 2.02 %, respectively, when the graphite size was $401.6{\mu}m$. The flexural strength of the composite was 10.3MPa when the graphite size was $401.6{\mu}m$. The lowest resistance to electron mobility was well correlated with the composite with lowest porosity. It was possible the flaky large graphite particles survive after the hot pressing process.

• Korean Journal of Food Science and Technology
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• v.36 no.3
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• pp.478-483
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• 2004

Effects of instant coffee on weight, plasma lipids, leptin levels, and fat cell size in high-fat diet-fed rats were investigated, Twenty-four male Sprague-Dawley rats, fed experimental diet containing 40% total dietary fat and 0, 0.6, 1.2, and 2.4% (w/w) instant coffee for 6 weeks, were divided into four experimental groups (n = 6). Feed efficiency ratio of 0.6% coffee group was higher than control group. Weight gain, organ weights, free fatty acid level, and fat cell size were not significantly different among groups. Triglyceride, total cholesterol, HDL-cholesterol, and leptin levels in plasma were significantly higher in 0.6% coffee group than control group. No significant difference in feed efficiency ratio, triglyceride, and leptin levels were found between control and 2.4% coffee group. These results suggest instant coffee may not have effect on obesity.

• Journal of the Korean Geotechnical Society
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• v.24 no.8
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• pp.125-135
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• 2008

Rigid-soft particle mixtures, which consist of sand and rubber, are investigated for the understanding of the stress-deformation and elastic moduli. Specimens are prepared with various size ratio sr between sand and rubber particles, and different volumetric sand fraction sf. Small strain shear waves are measured under $K_o$-loading condition incorporated with the stress-deformation test by using oedometer cell with bender elements. The stress-deformation and small strain shear wave characteristics of rigid-soft particle mixtures show the transition from a rigid particle behavior regime to a soft particle behavior regime under fixed size ratio. A sudden rise of $\Lambda$ factor and the maximum value of the $\zeta$ exponent in $G_{max}=\;{\Lambda}({\sigma}'_{o}/kPa)^{\zeta}$ are observed at $sf\;{\approx}\;0.4{\sim}0.6$ regardless of the size ratio sf. Transition mixture shows high sensitivity to confining stress. The volume fraction for the minimum porosity may depend on the applied stress level in the rigid-soft particle mixtures because the soft rubber particles easily distort under load. In this experimental study, the size ratio and volumetric sand fraction are the important factors which determine the behavior of rigid and soft particle mixtures.

• Journal of Nutrition and Health
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• v.31 no.3
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• pp.243-252
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• 1998

This study was conducted to investigated the short-term effects of early weaning and protein intake on organ and cell growth, nitrogen metabolism and physiological functions of rats. Five groups of early weaned rats separated from the dam on the 15th day postpartum were each given one five diets consisting of either one of the three levels of casein-low(8%), -normal (16%), and -high(32%), or a normal level (16%) of isolated soy protein(ISP) or egg yolk protein, for 7 days. The normal weaned rats were fed maternal breast milk for three weeks from birth. On the 22nd day postpartum , all the rats were sacrificed . The weight gain of the early weaned rats, especially the ones fed high protein, was observed to be significantly lower than that of the normal weaned rats. By the 15th day, of early weaning and especially in the ISP-fed rats, the total DNA contents of liver and kidney, which may be said to represent an index of cell numbers, significantly decreased, but their fresh and dry weight and protein/DNA ratio, allegedly representing an index of cell size, significantly increased , not affecting the cell number and cell size of brain. There were no differences in total serum protein and albumin concentrations between early and normal weaned rats. In the early weaned rats observed , the serum urea N and $\alpha$-amino N concentrations significantly increased in high protein-fed rats, and decreased in low protein-fed rats. Another observation was that no significant difference was noticed as regards to serum GOT activity, total bilirubin, uric acid, and creatinine concentration, which may represent indices of liver and kidney functions, among rat groups, GPT activity was an exception . These results suggest that premature weaning and the quality and quantity of dietary protein significantly affect organ and cell growth and nitrogen metabolism but does not seriously affect physiological functions in the neonatal development of rats.

• KSBB Journal
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• v.14 no.6
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• pp.665-671
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• 1999

In this study, enhanced production of 10-deacetylbaccatin III(10-DAB), a precursor of taxol in semisynthesis, was investigated in Taxus cuspidata cell suspension cultures. The effects of initial inoculum size and sugar concentration were examined to prove the relationship between the production of 10-DAB and cell growth. The cell growth was found to be stimulated in Schenk and Hildebrandt(SH) medium. The lower the inoculum size as well as initial sugar concentration, the faster the cell growth rate. When the initial sugar concentration was dept low, the production of 10-DAB into medium was increased. By using perfusion culture, continuous cell growth was possible until the end of culture and more than 34.67 g/L of cell concentration could by obtained. This is about 2.5 times higher level than that of control batch culture.

• The Transactions of the Korea Information Processing Society
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• v.4 no.7
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• pp.1781-1787
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• 1997

Future high speed networks are expected to use the Asynchronous Transfer Mode(ATM), which provides desired quality of service for the various traffic types(e.g., voice, video and data). Proper traffic control scheme helps ensure efficient and fair operation of networks. In this paper, we analyze various related traffic-control strategies and propose a new traffic control scheme and ATM control architecture with an integrated buffer management method and multi-thresholds in order to solve the problem of each class's cell loss ratio and cell delay in ATM networks. In addition, we evaluate the performance improvement of the proposed traffic control scheme through simulation. As shown in the result, the proposed traffic control scheme improves cell loss ratio in proportion to the buffer size.

• Korean Chemical Engineering Research
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• v.46 no.5
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• pp.938-944
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• 2008

The electro-optic properties of polymer-dispersed liquid crystal cells containing BDVE(Butanediol vinyl ether) in PN393 base pre-polymer were examined. The higher the contents of BDVE, the smaller becomes the droplet size. However, the droplet size was saturated around $3{\mu}m$ even at 40 wt% of BDVE. Both of contrast ratio and response time of PDLC cell fabricated with a new formula were found to be superior to the reference cell with PN393 by the factor of 4.9 and 0.15, respectively. However, the new formula made the operating voltage go higher compared to the reference cell of PN393 formula. Except for contrast ratio, response time as well as operating voltage were found to be highly stabilized by adding BDVE in PN393 base pre-polymer over the temperature range of $0{\sim}60^{\circ}C$ studied.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.8
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• pp.3054-3067
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• 2015

The phenomena of higher channel cross polarization discrimination (XPD) is mainly observed for future wireless technologies such as small cell network and massive multiple-input multiple-output (MIMO) system. Therefore, utilization of high XPD is very important and space-polarization division multiple access (SPDMA) with dual-polarized MIMO system could be a suitable solution to high-speed transmission in high XPD environment as well as reduction of array size at base station (BS). By SPDMA with dual-polarized MIMO system, two parallel data signals can be transmitted by both vertically and horizontally polarized antennas to serve different mobile stations (MSs) simultaneously compare to conventional space division multiple access (SDMA) with single-polarized MIMO system. This paper analyzes the performance of SPDMA for maximum ratio transmission (MRT) in time division duplexing (TDD) system by proposed dual-polarized MIMO spatial channel model (SCM) compare to conventional SDMA. Simulation results indicate that how SPDMA utilizes the high XPD as the number of MS increases and SPDMA performs very close to conventional SDMA for same number of antenna elements but half size of the array at BS.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.9
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• pp.3703-3708
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• 2015

Background: The neutrophil-to-lymphocyte ratio (NLR) is a strong predictor of mortality in patients with colorectal, lung, gastric cancer, pancreatic and metastatic renal cell carcinoma. We here evaluated whether preoperative NLR is an independent prognostic factor for non-metastatic renal cell carcinoma (RCC). Materials and Methods: Data from 327 patients who underwent curative or palliative nephrectomy were evaluated retrospectively. In preoperative blood routine examination, neutrophils and lymphocytes were obtained. The predictive value of NLR for non-metastatic RCC was analyzed. Results: The NLR of 327 patients was $2.72{\pm}2.25$. NLR <1.7 and NLR ${\geq}1.7$ were classified as low and high NLR groups, respectively. Chi-square test showed that the preoperative NLR was significantly correlated with the tumor size (P=0.025), but not with the histological subtype (P=0.095)and the pT stage (P=0.283). Overall survival (OS) and disease-free survival (DFS) were assessed using the Kaplan-Meier method. Effects of NLR on OS (P=0.007) and DFS (P=0.011) were significant. To evaluate the independent prognostic significance of NLR, multivariate COX regression models were applied and identified increased NLR as an independent prognostic factor for OS (P=0.015), and DFS (P=0.019). Conclusions: Regarding patient survival, an increased NLR represented an independent risk factor, which might reflect a higher risk for severe cardiovascular and other comorbidities. An elevated blood NLR may be a biomarker of poor OS and DFS in patients with non-metastatic RCC.

• Journal of Chest Surgery
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• v.15 no.2
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• pp.148-154
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• 1982

The experience with operative treatment for peripheral situated solitary circumscribed lesions of the lung at the Department of Thorac. & Cardiovasc. Surg., Korea University Hospital during 8 years from March 1974, through April, 1982 was reviewed. Our criteria for Solitary pulmonary nodule were 1. Round or Ovoid shape 2. Surrounded by normal lung Parenchyme 3. Well circumscribed peripheral location 4. No other visible pulmonary diseases on chest X-ray except minimal atelectasis or pneumonitis 5. Largest diameter less than 8 cm Of the 55 patients reviewed, there were 69% of malignancy and 31% of benign pulmonary diseases. In malignancy 38 patients, there were 18 patients with squamous cell carcinoma, 8 patients with undifferentiated large cell carcinoma, 2 patients with undifferentiated small cell carcinoma, 10 patients with adenocarcinoma and patient with metastatic carcinoma. In benign pulmonary nodule 17 patients, here were 5 patients with tuberculoma, 5 patients with aspergilloma, 2 patients with A-V fistula, 1 patient with pulmonary blastoma, 1 patient with paragonimiasis, and 1 patient with lung abscess. Overall male to female occurrence ratio was 39:16, and most prevalent age incidence was 7th decades. Most frequent size distribution was 4-6 cm in diameter. All of benign diseases were cured by resection and 66% of malignancy performed operation and has 75% resectability.