• Polymer(Korea)
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• v.24 no.5
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• pp.713-720
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• 2000

A polymer/iodine complex film was prepared using syndiotactic poly(vinyl alcohol) (s-PVA) with number-average degree of polymerization of 900 and syndiotactic diad content of 63.1%. In comparison with atactic-PVA/iodine films, degree of polarization of the s-PVA/iodine film was improved up to over 99% although a lower transmittance was obtained. By soaking in iodine/potassium iodide aqueous solution of a lower iodine concentration and subsequent drawing by 4 times, s-PVA/iodine film of a higher transmittance and degree of polarization was produced. The degree of iodine desorption of the s-PVA/iodine film in water were very low. The crystallinity and the d-spacing and crystal size of (100) plane increased at the early stage of soaking time, however, remained constant or decreased slightly with increasing soaking time. In consequence, s-PVA/iodine complex formation took place mainly inside crystal region at the initial stage of soaking time, whereas it occurred outside crystal region or physical adsorption of iodine dominated after sufficient soaking.

• Journal of radiological science and technology
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• v.19 no.2
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• pp.71-77
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• 1996

Studies were conducted to determine the clinical application of photodiode. We compared photodiode with ion-chamber as to change of tube potential, tube current, mAs and measured decreasing rate of penetration dose. When tube potential was changed from 60 kVp to 120 kVp, output of photodiode and ion-chamber were changed from 0.4 to 1.625, and 1.018 to 4.268, respectively. This was a good agreement to theory that $I=Kv^2it$(I is intensity, K is constant, v is tube potential, i is tube current, t is time). Characteristics for change of tube current and mAs were also a good agreement to theory. And comparison in decreasing rate of penetration dose was similar except above 6 cm in depth. Our results indicated that photodiode was a good instrument for relative measurement of radiation exposure, but we can not use the photodiode for absolute radiation dose.

• Applied Biological Chemistry
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• v.32 no.4
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• pp.332-337
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• 1989

Rheological properties of rehydrated freeze dried instant rice were investigated in comparison with that of cooked rice. The time changes in reciprocal hardness of instant rice grains at various rehydration temperatures$(60{\sim}90^{\circ}C)$ could be expressed by the first order reaction rate equation regardless of rehydration temperature and reaction rate constant increased as the rehydration temperature increased. Activation energy for rehydrating instant rice was 6.1 kcal/g-mol. Analysis of compressive stress relaxation test showed that the viscoelastic properties of both rehydrated instant rice and cooked rice grains could be expressed by 6-elements generalized Maxwell model. Rehydrated instant rice revealed higher relaxation decay than that of cooked rice and showed the elastic property increased by increasing the rehydration temperature.

• Child Health Nursing Research
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• v.11 no.2
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• pp.203-210
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• 2005

Purpose: In order to identify the usability of inguinal temperature in a neonatal unit, this study was done to compare inguinal temperature of newborns with rectal, axillary, and tympanic temperatures. Method: Fifty-one normal newborns admitted to the nursery of a university affiliated hospital participated in the study. Tympanic temperatures were taken with a tympanic thermometer. Inguinal, rectal, and axillary temperatures were taken with glass mercury thermometers, and were recorded every 1 minute until the reading remained constant for 2 times. The data were analyzed using the SPSS program. Result: The measurement time for inguinal temperatures in newborns was significantly longer than that for rectal temperatures, but was shorter than that for axillary temperatures. The mean temperature for the newborn's inguinal site was lower than for rectal, axillary, and tympanic temperatures (the lower side), but wasn't different from tympanic temperature (the upper side). The inguinal temperature was significantly correlated with rectal, axillary, and tympanic temperature. The inguinal temperature was not different according to general characteristics of the newborn. Conclusion: These findings indicate that measurement of inguinal temperature is a useful alternative to rectal temperature.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.14 no.4
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• pp.225-247
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• 2010

In this paper, we establish a two-competitive-prey and one-predator Holling type II system by introducing a proportional periodic impulsive harvesting for all species and a constant periodic releasing, or immigrating, for the predator at different fixed time. We show the boundedness of the system and find conditions for the local and global stabilities of two-prey-free periodic solutions by using Floquet theory for the impulsive differential equation, small amplitude perturbation skills and comparison techniques. Also, we prove that the system is permanent under some conditions and give sufficient conditions under which one of the two preys is extinct and the remaining two species are permanent. In addition, we take account of the system with seasonality as a periodic forcing term in the intrinsic growth rate of prey population and then find conditions for the stability of the two-prey-free periodic solutions and for the permanence of this system. We discuss the complex dynamical aspects of these systems via bifurcation diagrams.

• Journal of the Korean Society for Precision Engineering
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• v.23 no.3 s.180
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• pp.125-131
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• 2006

Recently air pollution has become an important issue. So, as tile number of vehicles increases, the noise pollution has become one of the most serious social issues nowadays. It is a muffler, which is one of the vehicle components. that has the hugest impact on the noise from the vehicle. And it also has a direct influence on the engine performance. So lately the research is proceeding on tile semi-active muffler which can control the back pressure variably by setting up the exhaust variable valve in the baffle to improve its internal structure. The inner parts of muffler which consist of a baffle, pipes and etc. appear to have the complicated turbulence phenomena by the pulsational wave of an unsteady state in the engine and by the structural characteristics of the inner parts. To analyze these phenomena, it is required to have an analysis of its constant quantity and quality. Therefore this study is to analyze with PIV measurement which can analyze the time and space variables, not with the point measurement method like former multi-point anemometer. It is to suggest proper design variables which need to make internal structure of the muffler improve though comparison between the passive type muffler and the semi-active muffler by fabricating a muffler which can be visualized.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.7
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• pp.1617-1625
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• 2010

Recently, the standardization of SVC technology which can provide adaptive video quality in diverse service environments has been completed. This paper proposes a layered encryption technique which takes into account the prioritized layer characteristics of SVC and control constant encryption complexity satisfying the target computational complexity. In particular, it analyzes the importance of NAL unit in the SVC video layer and suggests a method to apply appropriate encryption complexity proper for it. The effectiveness of the proposed method is proved through the comparison of time required for encryption and the reconstructed video quality using imperfect decryption key.

• Journal of Pharmaceutical Investigation
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• v.16 no.4
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• pp.139-147
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• 1986

A singly charged methyl orange(MO) anion was found to be extracted with chlorpheniramine maleate(CPM) as a 1 : 1 complex in chloroform. Of various solvents, MO-chloroform system gave a yellow color for CPM, while in the absence of CPM, an organic phase showed almost no color. In this way, the spectrophotometric method was investigated for the determination of CPM by solvent extraction. The addition of alcoholic bolic acid solution to the solvent extract gave a higher color stability and transparency at least 5 days, but the extract alone lost its color intensity significantly. CPM is determined by measuring the absorbance of the extracts over a range of $1{\sim}7{\times}10^{-4}M\;(39{\sim}273\;{\mu}g/ml)$ in aqueous solution at 423 nm. The molar absorptivity was $2.26{\times}10^3\;l,\;mol^{-1},\;cm^{-1}$. The absorbance of the extract was constant in the range of pH $3.7{\sim}4.6$. This novel method was applied for the determination of CPM in artificial and commercial preparations in comparison with the analytical method of CPM tablets in K.P.IV. The results obtained showed that the former was better in accuracy and time consumption than the latter.

• Magazine of the Korean Society of Agricultural Engineers
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• v.12 no.3
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• pp.2035-2042
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• 1970

Korean Janggi and Western plow to have developed for a long time in the east and west were tested and compared in their draft resistance. The charaderistic of Korean Janggi and plow to be able to make deep plowing, on of the most important factors influeneed the increased yield, were ofserved. The study was undertaken to obtain these basic factors' to device and construct the deep plowing Janggi. The results were as follow; 1. The draft resistance of Korean Janggi far less than that of plow and on the dry field, the influence of soil moisture contant to the draft resistance was larger in the Korean Janggi than in the western plow, but on the rice paddy, there was not differences between them. 2. The plow was more stable than that of Janggi in their operation. 3. The relation ship between the specific draft resistance and plowing depth was shown bygthe carved equation. $$K=Ax+\frac{B}{x}+C$$(K ; specific draft restance, x; plowing depth) A, B, C; Constant controled by soil and instrument factor) 4. Minimam values of the specific draft resistance were as follow; a. On the dry field; Korean Janggi; x = $8{\sim}14cm$ $4K=280{\sim}330gr/cm^2$$ Westean plow; x=$10{\sim}12cm$ $$K=480{\sim}490gr/cm^2$$ 6. On the rice paddy; Korean Janggi; x=$8{\sim}12cm$ $$K=255{\sim}280gr/cm^2$ Western plow; x=$7{\sim}10cm$ $$K=415{\sim}420grc/m^2$$

• International Journal of Reliability and Applications
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• v.15 no.2
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• pp.85-98
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• 2014

Accelerated life testing (ALT) is a well famous technique in life testing and reliability studies, this is particularly used to induce so high stress leading to failure of the highly reliable units quickly under stipulated duration of time. The step-stress ALT is one of the systematic experimental strategy of ALT applied to fail the units in steps. In this article we focus on two important issues (i) necessity of life tests at higher steps with relevant causes (ii) to develop a new optimum test plan for 3-step SSALT under the modified cumulative exposure model proposed by Khamis and Higgins (1998). It is assumed that the lifetime of test units follows Rayleigh distribution and its scale parameter at constant stress level is assumed to be a log-linear function of the stress. The maximum likelihood estimates of the parameters involved in the step-stress ALT model are obtained. A simulation study is performed for numerical investigation of the proposed new optimum plan 3-step, step-stress ALT. The necessity of the life test units at 3-step step-stress is also numerically examined in comparison to simple step-stress setup.