• The Korean Journal of Physiology
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• v.20 no.2
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• pp.218-224
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• 1986

The characteristics of anion exchange with internal $HCO_3\;^{-}\;(or\;OH^-)$ was studied by determining the time course of hemolysis in isoosmotic ammonium salt solution in human erythrocytes. The effects of inhibitors, pH and temperature on the exchange between internal $HCO_3\;^-\;(or\;OH^-)$ and external $Cl^-$ were observed and the permeabilities of various organic and inorganic anions were also measured. The results were compared with data previously reported from the experiments using radioisotopes. The results are as follows; 1) SITS $H_2DIDS$ and furosemide inhibited the hemolysis of erythrocytes in isoosmotic $NH_4Cl$ solution in a dose·dependent manner, and the concentrations for lengthening twice the time for $half-hemloysis(t_{1/2})\;were\;2.3{\times}10^{-7},\;1.3{\times}10^{-7}\;and\;2.5{\times}10^{-5}M$, respectively. 2) Acetazolamide also shifted the time-dependent hemolytic curve to the right in a dose-dependent manner, and the concentrations for lengthening twice $t_{1/2}\;was\;2.4{\times}10^{-5}M$. 3) The time-dependent hemolysis was delayed by decreasing pH from 7.0 to 6.2, but w·as not affected by the change of pH in the range of 7.0 to 8.2. 4) The time for $half-hemloysis(t_{1/2})$ showed a temperature-dependency and Arrhenius plot exhibited a break point at $20^{\circ}C$. The apparent activation energy calculated from this plot was 18.1 kcal/mol between $2^{\circ}C-20^{\circ}C$ and 11.2 kcal/mol between $20^{\circ}C-37^{\circ}C$, respectively. 5) The apparent permeabilities of various inorganic anions based on $t_{1/2}$ were in the order of $Cl^->NO_{3}\;^->SCN^->SO_4\;^{2-}>SSO_3\;^{2-}>HPO_4\;^{2-}$. which was similar with the previous reports based on the experiment using radioisotopes. The results Obtained from this study are comparable with the previous data reported from the experiments using radioisotopes. This indicates that the hemolysis of erythrocytes in isoosmotic ammonium salt solution can be used as a simple and good method for the study of anion exchange in erythrocyte membrane.

• Journal of the Korean Society of Food Science and Nutrition
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• v.10 no.1
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• pp.53-60
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• 1981

Dehydration phenomena has been studied for the shiitake mushroom Lentinus edodes sanryun No.1, through which examine the effect of temperature and air velocity and derivation of its kinetics. Temperature effect for the dehydration rate constant were examined under the constant air velocity (1.5m/sec) with the variation of temperature from $40^{\circ}C$ to $55^{\circ}C$. Water content were reduced exponentially with the course of time and calculated dehydration rate constant values varies with temperature with an Arrhenius-type relationship, which had been expected in the chemical reaction kinetics. Influence of air velocity for the dehydration rate constant under the constant temperature $(45^{\circ}C)$ showed interesting results. For the range 1.0m/sec to 2.0m/sec, dehydration rate constant values are increased with the air velocity, but for the 2.0 to 3.1m/sec, dehydration rate constant values are decreased which were caused by case hardening. One of the selected conditions in the optimal dehydration range, temperature $50^{\circ}C$, air velocity 2m/see, and its measured humidity 38-41%, mathematical model of dehydration curve and dehydration rate equations were developed and the resulting kinetic models were X=6.94 $e^{-0.345t}$ and dx/dt = -2.39 $e^{-0.345t}$

• Journal of Digital Contents Society
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• v.15 no.1
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• pp.19-27
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• 2014

In order to estimate the life of 2,5 inch HDD which is adopted by PC environment, make the test plan which reflect the failure mode of market, make the test model of accelerated life test which reflect the stress of temperature. after an analysis of the environment of PC using, test procedure was decided that operation was write 50 % and read 50 %, and then access method was sequential 50 % and random 50%. The acceleration life test was executed on condition that temperature was $50^{\circ}C$ and $60^{\circ}C$, performance was 95 % in max performance, test time was 1000 hours. by the test of goodness of fit of anderson-darling of the failure data during test, it was confirmed that the distribution of failure fellow weibull. test for shape and scale was equal, and shape parameter was 0.7177, characteristic life was 429434 hours at normal user condition($30^{\circ}C$) by the analysis of weibull-arrhenius modeling. It made no difference about the statistics when equality test was executed. The activation energy was 0.2775eV. In analyzing between the failure samples of acceleration test and the samples of market return even though there is detail difference about the share of failure mode, the rank of share was almost same. This study suggest the test procedure of acceleration test of 2.5 inch HDD in PC using environment, and help the life estimation at manufacture and user.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.10
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• pp.182-188
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• 2016

A decoy is a weapon system that can protect vessels from an enemy's torpedo. Thus, the decoy should be able to operate in the field without any failure. Because the decoy can be inoperable once its sealing is broken and water permeates inside the system, the hermetic sealing capability considering the operational environment is mandatory. To be hermetically sealed, a rubber-type O-ring is generally used in a decoy system. The sealed performance of rubber-type products, however, tends to age and deteriorate with time. Therefore, the O-ring needs to be maintained or changed periodically. This paper proposes a method to estimate the proper maintenance period using the hardness and elongation percentage, which represents the performance of the O-ring product and test data from Accelerated Life Test (ALT) of the product. The O-ring used in this paper is a NBR type, and the temperature was chosen to be the main accelerating factor as referenced in many studies. The criteria for the failure of the O-ring was set for the product to be 50% degraded compared to the initial performance. In addition, the Korean standard KS M 6518 was adopted and referenced for the preparation of test samples and the calculation of estimates. The O-ring's predicted life was simulated by analyzing the test results from a computer program, and the optimized maintenance period for the product was determined.