• Journal of Gastric Cancer
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• v.3 no.2
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• pp.97-103
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• 2003

Purpose: This study aims to determine the infection rate of Helicobacter pylori (H. pylori) in gastric cancer patients who received gastrectomies, and to compare the rates of H.pylori infection detected by serological test and that of histopathological test, and to evaluate its clinical meaning. Materials and Methods: Fifty two patients were selected from those who underwent gastrectomies at the Department of Surgery, Samsung Medical Center, from March 1997 to May 1997. The control group consisted of healthy 103 persons visited the center for health promotion in Samsung Medical Center. In both groups, we quantitatively checked serum level of IgG anti H. pylori antibody titer by ELISA using GAP IgG test kit (BioRad, USA) for the serological test, and we microscopically examined the surgical specimen stained by Warthin-Starry silver staining method for the histopathological test. Results: The seropositive rate of H. pylori in the patients' group was $71.2\%$ (37/52), and the control group was $65.0\%$ (67/103). The difference between two groups was statistically significant. However the histopathological study showed that the overall detection rate of H. pylori was $61.5\%$ (32/52) in the patients' group and $61.2\%$ (63/103) in the control group; nd this difference was not statistically significant Conclusion: We could confirm that H.pylori infection rate in the gastric cancer resected patients was statistically higher than in the normal healthy persons even in small population. And the detection method for the H. pylori infection by serological test was presumed to be better than that of histopathological test using surgical specimen. Further study for the larger population by well-organized multicenters will be needed.

• Journal of the Korean Society of Clothing and Textiles
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• v.13 no.3 s.31
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• pp.187-196
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• 1989

The purpose of this study is to find at the basic data for the appropriate compressibility of the pillows for the Koreans as well as, for the appropriate conditions to establish the estimating criterion for the pillows on the market place. This paper also aim to grasp thr compressibility of the materials used to make the pillows for sale. The appropriate compressive rate of the pillows have been investigated by sensuous test. The compressive rate, recovery rate, and decreasing rate of compression and recovery have been investigated by means of ergonomic and physical experiments. The results were as follows; 1) By sensuous test, the compressive rate of the pillows for the most comfortable state turns up $45\%{\pm}5\%$ in men and women. 2) As for the compressive rate and recovery rate of the eight pillow materials on market, panya, duck feather two kinds of synthetic fiber are highest, wood is lowest. 3) The compressive rate of panya, duck feather, and two kinds of fiber is within the range of the comfort by sensuous test. 4) In the durability of the compressive rate and recovery rate against the repeated use of the pillows, duck feather is in the highest grade, panya is the lowest grade and the others are graded between two.

• Tribology and Lubricants
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• v.36 no.3
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• pp.117-123
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• 2020

In this study, the effect of the pre-mild wear mode test condition on the subsequent severe wear behavior of carbon steel has been investigated when the wear mode is varied according to the sliding speed change during sliding contact. Two sliding speeds of 0.3 m/s and 3 m/s for the mild wear mode test have been chosen and a sliding speed of 1 m/s for the severe wear mode test. A mild wear mode test at two different sliding speeds has been carried out during the severe wear mode test and total sliding distance of the mild wear mode test has been changed at this time. As a result, it could be found that the wear rate of carbon steel under the severe wear mode test after performing a pre-mild wear mode test is significantly reduced, compared with that before performing. However, its wear rate was slightly higher than that under the mild wear mode test. Oxides produced during the pre-mild wear mode test have been found to play a significant role in reducing the wear rate under the subsequent severe wear mode test. In particular, it was found that the effect of a pre-mild wear mode test performed at the sliding speed of 3 m/s has more rapid and the reduction in the wear rate was greater than thst at the sliding speed of 0.3 m/s.

• Journal of the Korean Society for Heat Treatment
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• v.27 no.4
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• pp.180-184
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• 2014

In order to make clear relationship between high temperature tensile properties and fine microstructure of rapidly solidified cast-type Ni-base superalloys without heat treatment required for consolidation process, tensile test was carried out by changing strain rate from $5{\times}10^{-5}s^{-1}$ to $2{\times}10^{-2}s^{-1}$ and test temperature from $900^{\circ}C$ to $1050^{\circ}C$ using IN738LC and Rene'80 melt-spinning ribbons by twin roll process which were superior to ribbons by single roll process from the viewpoint of structure homogeneity. The dependence of tensile strength on strain rate and test temperature was studied and strain rate sensitivity, m, were estimated from tensile test results. From this study, it was found that tensile strength was influenced by ${\gamma}^{\prime}$ particle diameter, test temperature and strain rate, and m of ribbons exhibited above 0.3 over $950^{\circ}C$.

• Proceedings of the Korean Reliability Society Conference
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• 2000.11a
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• pp.365-371
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• 2000

The problem of trend change in the failure rate is great interest in the reliability and survival analysis. In this paper we develop a test statistic for testing whether or not the failure rate changes its trend using random censored data. The asymptotic normality of the test statistic is established. We discuss the efficiency values of loss due to censoring.

• International Journal of Quality Innovation
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• v.1 no.1
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• pp.58-63
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• 2000

The problem of trend change in the failure rate is great interest in the reliability and survival analysis. In this paper we develop a test statistic for testing whether or not the failure rate changes its trend using random censored data. The asymptotic normality of the test statistic is established. The efficiency values of loss due to censoring are discussed.

• Journal of Korean Society for Quality Management
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• v.29 no.1
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• pp.41-46
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• 2001

The problem of trend change in the failure rate is great interest in the reliability and survival analysis. In this paper we develop a test statistic for testing whether or not the failure rate changes its trend based on a complete sample. Monte Carlo simulations are conducted to investigate the speed of convergence of the proposed test statistic.

• Proceedings of the KSR Conference
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• 1999.11a
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• pp.385-390
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• 1999

In this paper, we investigated the wear rate, braking temperature and stopping distance of the composite brake shoe for diesel locomotive in the field test. The wear rate and braking temperature of the composite brake shoe would rather than cast iron. Also, the stopping distance of composite brake shoe is 450m at 100km/h. This result of field test shown that the density distribution of the composite brake shoe influence on wear rate.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1994.10a
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• pp.74-79
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• 1994

The log-log presentation of stress versus Larson-Miller parameter is obtained by uniaxial tensile test instead of the long time creep test. The used material for example calculations is SUS304 stainless steel. The temperature of the uniaxial tensile test can be determined by the Larson-Miller parameter of the design stress and the 0.1hr's rupture time of the uniaxial tensile test. The rupture time at the design temperature and stress can be determined by the Larson-Miller parameter of the stress. The average creep rate is the total deformation of the tensile test divided by the rupture time at the design stress and temperature. The liner trend and the order of the data of the average creep rate by this method is almost same as that of experimental results.

• Journal of Korean Society of Forest Science
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• v.94 no.2 s.159
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• pp.73-81
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• 2005

This study was conducted to examine the geographic variation among provenances of Pinus densiflora in survival rate and height growth at four test plantations (Jungsun, Chungju, Naju, and Jeju). The plantations were parts of the eleven provenance trials of Pinus densiflora established by Korea Forest Research Institute in 1996. The survival rate and height growth were significantly different among test plantations at $p{\leq}0.01$. Latitude and longitude of test plantation were negatively correlated with survival rate and height growth. On the other hand, annual mean temperature, mean temperature (Nov.~Feb.), extremely low temperature (Dec.~Feb.), and annual mean growing days of test plantation were positively correlated with these two. The relationships between growth variables and geographic variables were analysed with canonical correlation analysis. A considerable amount of variation in survival rate and height growth was explained by latitude, annual mean growing days, extremely low temperature (Dec.~Feb.) and extremely high temperature (Nov.~Feb.) of provenances. It is estimated that up to 47.1% and 67.4% of the genetic variability in survival rate and height growth was attributable to the environmental variability of the provenances, respectively. The response surface curve of survival rate and height growth was plotted against latitude and longitude to examine growth performance of provenances for each test site. Generally, the local provenances showed better survival rate and height growth.