• Journal of the Korean Applied Science and Technology
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• v.36 no.4
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• pp.1050-1059
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• 2019

The self diffusion, hole volume, and flow thermodynamic parameters of polyamide fibers were calculated from rheological parameters and crystallite size in order to study of flow segments in amorphous region. The stress relaxation of polyamide filament fibers were carried out in air and various solvents at various temperatures using the tensile tester with the solvent chamber. The rheological parameters were obtained by applying the experimental stress relaxation curves to the theoretical equation of the Ree-Eyring and Maxwell non-Newtonian model. It was observed that the rheological parameters of these polyamide filament fibers are directly related to the relaxation spectra, self diffusion, viscosities, and activation energies of flow segments.

• Nuclear Engineering and Technology
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• v.34 no.6
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• pp.566-573
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• 2002

Neutron activation analysis based on $textsc{k}$$_{o}$-standardization method＃ ($textsc{k}$o-NAA) is Com as one of the most remarkable progresses of the NAA with advantages of experimental simplicity, high accuracy, excellent flexibility with respect to irradiation and counting conditions, and suitability for computerization. This study was carried out to determine the reactor neutron spectrum parameters, i.e. $\alpha$ and f as the main factors of irradiation quality at NAA ＃1 irradiation hole on HANARO research reactor, to evaluate peak detection efficiency of the gamma-ray spectrometer for the use in the $textsc{k}$$_{o}$ experiments and to compare the measured concentration results with the certified values of some SRMs applying the experimentally determined to-parameters.ers.

• Journal of Environmental Science International
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• v.25 no.2
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• pp.281-288
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• 2016

After analyzing of heating value of four kinds of RDF, the RDF-D has the highest heating value, was chosen to be mixed with carbonized sludge by different ratio. The 85%:15% ratio, which has the highest efficiency, was analyzed with thermogravimetric and pyrolysis kinetics. Applying of Kissinger method, activation energy was obtained from slope which is calculated from relation of ln(${\beta}/T^2{_m}$) and $1/T_m$. The kinetic parameters obtained from Kissinger method were 46.06 kJ/mol of RDF, 55.99 kJ/mol of carbonized sludge and 40.68 kJ/mol of mixture of RDF and carbonized sludge. The mixture of RDF and carbonized sludge has the lowest activation energy and frequency factor, during thermal decomposition reaction it has the slowest reaction rate and needs the lowest energy. Although activation energy with pyrolysis of RDF was irregularly scattered, it showed that activation energy was stabilized by co-pyrolysis of RDF and additives(Carbonized Sludge).

• Biomedical Science Letters
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• v.12 no.4
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• pp.337-341
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• 2006

Platelets clearly play an important role in inflammatory responses. In this study, we aimed to evaluate the relationship between aging and platelet activation. A total number of 799 persons (383 males and 416 females), who were apparently healthy and aged more than 20 years were recruited by a health promotion center in a community-based hospital in Seoul, Korea. We collected material data about their medical history and health behavior. Platelet parameters including mean platelet component (MPC), mean platelet volume (MPV), and platelet component distribution width (PCDW) were determined within 1 hour after blood collection using the ADVIA 120 automated hematology analyzer. The MPC of the women ($27.2{\pm}1.2$) was significantly love. than that of the men ($27.5{\pm}1.3$). The MPC of all participants was found to decrease with increasing age (P<0.01). Study participants in their twenties had the highest MPC ($27.7{\pm}1.1$), followed by those in their thirties ($27.6{\pm}1.1$), forties ($27.4{\pm}1.3$), fifties ($27.2{\pm}1.3$), sixties ($27.2{\pm}1.2$) and seventies ($27.1{\pm}1.2$). Multiple regression analysis showed that aging and gender were related with MPC after adjusting for confounding factors, including age, gender, smoking habit, hypertension, diabetes, body mass index and total cholesterol level. The this study shows that aging is related to platelet activation. Future research will need to determine the implications of increased platelet activation with aging, especially regarding the increased incidence of cardiovascular diseases and related mortalities that occur in older age groups.

• Investigative Magnetic Resonance Imaging
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• v.10 no.1
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• pp.26-31
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• 2006

Purpose : To evaluate the effect of global scaling analysis on brain activation for sensory and motor functional MR imaging study. Materials and methods : Four normal subjects without abnormal neurological history were included. Arm extension-flexion movement was used for motor function and 1KHz pure tone stimulation was used for auditory function. Functional magnetic resonance imaging was performed at 3T MRI (GE, Milwaukee, USA) using BOLD-EPI technique and SPM2 was employed for data analysis. On data analysis, the brain activation images were obtained with and without global scaling by fixing other parameters such as motion correction and realignment. Results : The difference in brain activation between no scaling and global scaling was not large in case of right upper extremity movement (p<0.000001). For auditory test, brain activation with global scaling showed larger activation than that of without global scaling (p<0.05). Conclusion : A caution must be taken into account when analyzing functional imaging data with global scaling especially for functional study of small local BOLD signal change.

• Journal of the Korean Chemical Society
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• v.37 no.6
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• pp.555-561
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• 1993

Ultraviolet spectrophotometric investigation has been carried out on the system of iododestannylation iodine and tetramethyltin in methanol. The transient CT absorption spectrum can be observed and the subsequent disappearance of CT absorption spectrum was accompained by the cleavage of tetramethyltin with iodine. From there, the rate constants for the iododestannylation were determined at 10, 25 and 35$^{\circ}C$ up to 1600 bar and the reaction rates were increased with increasing temperature and pressure. From these rate constants, the values of the activation parameters (${\Delta}V^\neq,\;{\Delta}{\beta}^{\neq},\;{\Delta}H^{\neq},\;{\Delta}S^{\neq}\;and\;{\Delta}G^{\neq}$) were obtained. The activation volumes and activation compressibility coefficients were both negativity. The activation enthalpies were positive and activation entropies had large negative values. From these values discussed in terms of solvent structure variation of transition state and mechanism. From these results, it was found that the reaction is followed with $S_E2$ mechaenism and weakened $S_E2$ mechanism nature by increasing pressure.

• Elastomers and Composites
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• v.46 no.3
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• pp.245-250
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• 2011

The self diffusions and hole volumes of amorphous region of poly(acrylonitrile)-poly(vinyl chloride) fibers were investigated by experiments of stress relaxation. The experiments of stress relaxation were carried out using the tensile tester with the solvent chamber. The flow parameters of filament fibers were obtained by applying the experimental stress relaxation curves to the theoretical equation of stress relaxation. From the flow parameters, the hole volumes, self diffusions, viscosities and thermodynamic parameters of solid polymers were calculated. It was observed that the flow parameters of these samples are directly related to the hole volumes, self diffusions and flow activation energies of flow segments.

• The Journal of Korean Physical Therapy
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• v.34 no.6
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• pp.298-303
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• 2022

Purpose: The purpose of this study was to figure out how PAP (Post-Activation Potentiation) phenomenon affects short-term performance efficiently. Methods: This study was conducted with 18 Taekwondo athletes and 16 healthy adults. By using isokinetic dynamometer, two different intervention, TDP (Top-down program) and BUP (Bottom-up program), were performed to measure isokinetic parameter; (peak torque: PT, total work: TW, average power: AP, and average torque: AT) of knee extensor for intragroup, intergroup comparison and two-way ANOVA. Results: The Taekwondo athletes group showed statistically significant differences in all isokinetic parameters PT, TW, AP, and AT after TDP (p<0.05). However, in the healthy adult group, the difference in isokinetic parameters according to the exercise sequence was not statistically significant. (p>0.05). PT and TW at TDP were statistically significant (p<0.05) when the rate of change in TDP and BUP was compared and analyzed considering the difference in physical ability between the Taekwondo athlete group and the healthy adult group. However, AP and AT were not statistically significant. Finally, when examining the interaction between the two groups and two exercise sequence according to isokinetic parameters, only TW (p<0.05) showed a statistically significant interaction, while PT (P=0.099), AP (P=0.103), and AT (P=0.096) did not. This study suggests that short-term performance can be improved through the PAP phenomenon when TDP is applied to the Taekwondo group. Conclusion: According to our result, for Taekwondo athletes, if the goal is to improve short-term performance just before the main game, we suggest a training program through TDP.

• Journal of the Korean Chemical Society
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• v.42 no.2
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• pp.150-155
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• 1998

Kinetic studies on the reaction of isoquinoline with para-substituted benzylbromides were conducted under various pressures (1 ~1000 bar) in acetonitrile. From the rate constants obtained, the activation parameters such as$\DeltaV^{\neq}, \Delta\beta^{\neq}, \DeltaH^{\neq}, \DeltaS^{\neq}, \DeltaG^{\neq}$ and Ea were evaluated. Reaction rate increasing the pressure and temperature. The activation compressibility coefficient and the activation entropy showed negative values. From the substituent effect and the results, it was found that the reaction proceeds through $S_N2$ mechanism, but the structure of transition state was slightly changed with substituents and pressure.

• Textile Coloration and Finishing
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• v.22 no.2
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• pp.94-100
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• 2010

Colored compounds adsorption from the textile dyeing effluents on activated carbons produced from various indigenous vegetable sources by zinc chloride activation is studied. The most important parameters in chemical activation were found to be the chemical ratio of $ZnCl_2$ to feed (3:1), carbonization temperature (460-470 $^{\circ}C$) and time of activation (75 min). The absorbance at 511 nm (red effluent) and 615 nm (blue effluent) are used for estimation of color. It is established that at optimum temperature ($50^{\circ}C$), time of contact (30-40 min) and adsorbent loading (2 g/L), activated carbons developed from rain tree (Samanea saman) saw dust and blackberry (Randia formosa) tree saw dust showed great capability to remove color materials from the effluents. It is observed that adsorption of reactive dyes by all types of activated carbons is more than that of disperse dyes. It is explained that because of its acidic nature the activated carbon can adsorb better reactive dye particles containing large number of nitrogen sites and $-SO_3Na$ group in their structure. The use of activated carbons from the indigenous biomass would be economical, because saw dusts are readily available waste worldwide.