• 한국식품과학회지
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• 제36권4호
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• pp.580-585
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• 2004

단감의 호흡에 미치는 산소, 이산화탄소 가스조성과 저장온도의 영향을 조사하기 위하여 비경쟁억제 효소반응속도식$(R=V_m[O_2]/(K_m+(1+[CO_2]/K_i)[O_2]))$과, Arrhenius 식(R=A exp(-E/$(R^*T)$)을 각각 모델로 하였다. 호흡 data는 0, 5, $20^{\circ}C$에서 폐쇄계방법으로 수집하였다. 0, $5^{\circ}C$에서 $K_m$은 0.1%이하, $K_i$는 100%이상이었고, $20^{\circ}C$에서 산소소비와 이산화탄소 발생의 $K_m$은 각각 10.72%와 3.25%로 크게 증가하였고, $K_i$는 각각 59.6%와 44.6%로 크게 감소하였다. 활성화에너지는 산소농도가 낮아지고 이산화탄소 농도가 높아질수록 감소하였고, 산소소비의 활성화에너지가 이산화탄소 발생의 활성화에너지보다 낮았다. 이는 이산화탄소 발생 호흡량이 산소소비 호흡량에 비해 온도의 영향을 많이 받고, 산소감소와 이산화탄소 증가에 따른 호흡량 감소 효과는 저온에 비해 고온에서 커지는 경향이었다. 이는 산소소비와 이산화탄소 발생의 $K_m$과 $K_i$값 비교에 의한 예측과 일치하는 결과이다. 이상의 간을 근거로 하여 각 온도별 MA포장 내 공기조성 변화의 예측하였고, 또한 실제 실험으로 조사된 값은 일치하였다. 따라서 단감의 최적 MA 포장조건설정에 있어서 효소반응속도론에 근거한 호흡모델이 타당한 것으로 판단되었다.

• Preventive Nutrition and Food Science
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• 제2권4호
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• pp.354-359
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• 1997

Optimal cultivation conditions for the production of phenylalanine ammonia-lyase(PAL) from Rhodotorula aurantiaca K-505 were selected, and the kinetic parameters of the produced PAL were determined. The most suitable carbon and nitrogen sources were glucose and tryptone, respectively. The strain expressed PAL constituttively when using the optimized semi-complex media. High cell density culture could be critical for maximal production of PAl since the PAL ynthesis was growth associated. maximum PAL activity was observed at initial pH 6.0. although the ll growth was not markedly affected by temperature between 22 and 28$^{\circ}C$, the cells yielded the maximum PAL activity when cultivated at 22$^{\circ}C$. The maximum activity for deamination of L-phenylalnine to trans-cinnamic acid was observed around pH 8.8. The PAL activity gave the maximum at 45$^{\circ}C$, and greatly decreased at higher than 5$0^{\circ}C$. Activation energy({TEX}$E_{a}${/TEX}) calculated from Arrhenius equation was 6.28 kcal/mol in the range of 22$^{\circ}C$ to 4$0^{\circ}C$. A oolf plot showed that the enzyme reaction follows Michaelis-Menten equation, whose {TEX}$K_{M}${/TEX} and {TEX}$V_{max}${/TEX} values were 4.65$\times${TEX}$10^{-3}${/TEX} M and 0.89$\mu$ mol/mg-min respectively.

• 한국염색가공학회지
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• 제8권2호
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• pp.16-24
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• 1996

Polyester microfiber fabrics were alcoholysed at 120, 140, and 16$0^{\circ}C$ in 0.5, 1.0, and 1.5% of sodiumglycerolate/glycerol solutions(NaGR) up to 80% and the characteristic decomposition features were compared and discussed with the results of the hydrolysis done by 5% sodium hydroxide solution(NaOH) at 80, 90, and 10$0^{\circ}C$. The resulting activation thermodynamic parameters calculated by the combined use of the Arrhenius equation and the Eyring equation were in NaOH case ${\Delta}H^*$=- 13.89 kcal/mol, ${\Delta}S^*$/=-38.12 cal/mol K, and ${\Delta}G^*$=25.25 kcal/mol and in NaGR case ${\Delta}H^*$=29.81 kcal/mol, ${\Delta}S^*$=-2.29 cal/mol K and ${\Delta}G^*$=30.49 kcal/mol. Since in all cases NaGR-PET system has higher activation thermodynamic parameters, it was concluded that NaGR-PET reaction system is more favorable at high temperatures and occurs in a less selective fashion, in comparison to the NaOH-PET reaction system.

• 대한기계학회논문집B
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• 제23권2호
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• pp.175-184
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• 1999

A theoretical study on the turbulent round jet diffusion flame impinging on the wall was carried out to predict the characteristics and structure of Impinging jet flame and heat transfer to the wall. Finite chemistry via Arrhenius equation and eddy dissipation model was adopted as a combustion model, and the Favre averaging and $k-{\varepsilon}$ model were Introduced In the theoretical modeling. The SIMPLE algorithm was applied to the calculation. All the transport properties were considered as the variable depending on the temperature and composition. For the parametric study, the distance from nozzle to impinging wall and Reynolds number at nozzle exit were chosen 88 the major parameters. As the results of the present study, the characteristics of flow fields, the distributions of main variables and each chemical species and the flame shapes were obtained. The heat transfer rate from the flame to the wall and the effective heating area were calculated to investigate the Influences of the major parameters on the heat transfer characteristics.

• 대한기계학회논문집A
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• 제33권4호
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• pp.366-372
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• 2009

Creep life prediction has been commonly used by a time-temperature parameter (TTP) which is correlated to an applied stress and temperature, such as Larson-Miller (LM), Orr-Sherby-Dorn (OSD), Manson-Haferd (MH) and Manson-Succop (MS) parameters. A stress-temperature linear model (STLM) based on Arrhenius, Dorn and Monkman-Grant equations was newly proposed through a mathematical procedure. For this model, the logarithm time to rupture was linearly dependent on both an applied stress and temperature. The model parameters were properly determined by using a technique of maximum likelihood estimation of a statistical method, and this model was applied to the creep data of Alloy 617. From the results, it is found that the STLM results showed better agreement than the Eno’s model and the LM parameter ones. Especially, the STLM revealed a good estimation in predicting the long-term creep life of Alloy 617.

• 품질경영학회지
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• 제38권4호
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• pp.504-511
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• 2010

A fuze detonator comprising star shells is an important device so that its failure usually leads to failure of the shells. In this paper, accelerated degradation tests of RD1333 (lead azide) using temperature stress were performed, and then degradation data of explosive power for the detonator were analyzed to predict the storage lifetime of detonator. Degradation data analysis to estimate the storage lifetime is based on a distribution-based degradation process. Statistical distribution parameters of explosive power degradation measures at each time were estimated for each temperature level, and then reliability of the detonator for each accelerated temperature level was estimated using both time-varying distribution parameters and critical level of explosive power. Arrhenius model was applied to estimate storage lifetime of the detonator under the field temperature condition. Accelerated distribution-based degradation analysis to estimate storage lifetime is explained in detail, and estimation results are compared to field data of storage lifetime in this paper.

• 한국응용과학기술학회지
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• 제14권3호
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• pp.39-46
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• 1997

Ultraviolet spectrophotometric investigation has been carried out on the rate constants for 1,3-dipolar cycloaddition of 4-substituted-3-phenyloxadiazole derivatives with dipolarophiles such as phenyl acetylene, propiolic acid methyl ester and dimethylacetylene dicarboxylate. From there, the rate constants for 1,3-dipolar cycloaddition were determined at 80, 100 and $120^{\circ}C$, and the reaction rates were increased with increasing temperature. From these rate constants, the values of the thermodynamic activation parameters were obtained. Some thermodynamic activation parameters such as $E_{\alpha}$, ${\Delta}H^{\ast}$, ${\Delta}S^{\ast}$ and ${\Delta}G^{\ast}$ from Arrhenius equation were also calculated for the electrophilic 1,3-dipolar cycloaddition of 3-phenyloxadiazole derivatives with dipolarophiles. In order to the proposal the mechanism and reactivity of 1,3-dipolar cycloaddition reaction, the effect of substituents having various kinds of electron withdrawing or releasing groups were examinated. Considering the effect of substituents, an electron withdrawing group attached at the 4-carbon position in 3-phenyloxadiazole derivatives decreases the reaction rate because of the lack of electron density in 3-phenyloxadiazole ring.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 추계학술대회
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• pp.1604-1610
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• 2004

A steady dilute premixed combustion at transonic speeds in a diverging channel is investigated. The model explores the nonlinear interactions between the near-sonic speed of the flow, the small changes in geometry from a straight channel, and the small heat release due to the one-step first-order Arrhenius chemical reaction. The reactive flow can be described by a nonhomogeneous transonic small-disturbance (TSD) equation coupled with an ordinary differencial equation for the calculation of the reactant mass fraction in the combustible gas. The asymptotic analysis results in the similarity parameters that govern the reacting flow problem. The model is used to study transonic combustion at various amounts of incoming, reactant mass, reaction rates, and channel geometries.

• 품질경영학회지
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• 제24권4호
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• pp.29-43
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• 1996

This paper identifies these data by the data diagnosis in lognormal distribution and presents the method to obtain exact parameter estimates and confidence intervals of regression line. The life-stress relationship uses Arrhenius model and life data generate Class-H insulation complete data by simulation. Also, the method to estimate parameters uses least squares estimation and externally Studentized residuals can be used as test statistics for identifing outliers. And influential cases are identified by Cook's distance. This research is intended to obtain the useful information for the life of products and test method, to save time and costs, and to help optimum accelerated life test plans.

• Food Science and Biotechnology
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• 제18권1호
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• pp.202-206
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• 2009

Drying characteristics of fresh Korean-type rehmannia (jiwhang) noodle was investigated to determine drying kinetic parameters under the experimental conditions of 5 temperatures (30, 40, 60, 80, and $90^{\circ}C$). Drying curve of the noodle showed a biphasic pattern of decrease in drying rate with initial rapid drying followed by slow dehydration as the progress in drying. In all drying conditions, only falling drying rate period was observed and the drying rate of the noodle was greatly influenced by the drying temperature. The effective diffusion coefficients ($D_{eff}$) were determined by the diffusion model and their temperature dependency was determined using an Arrhenius equation. The activation energy ($E_a$) values for the drying of the noodle were 19.94 and 21.09 kJ/mol at the initial and the latter stage of dehydration, which were comparable to those of pasta or Japanese udong dehydration.