• Bulletin of the Korean Chemical Society
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• v.25 no.3
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• pp.365-372
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• 2004

Two simple, rapid and sensitive spectrophotometric methods for the determination of three fluoroquinolones, namely levofloxacin, norfloxacin and ciprofloxacin have been performed either in pure form or in their tablets. In the first method, levofloxacin and norfloxacin are directly treated with bromocresol green (BCG) in dichloromethane while ciprofloxacin is allowed to react with the same dye in aqueous acidic buffer. Highly yellow colored complex species were formed instantaneously in case of levofloxacin and norfloxacin or after extraction into dichloromethane for ciprofloxacin. The formed complexes are quantified spectrophotometrically at their absorption maxima at 411 nm for levofloxacin and 412 nm for norfloxacin and ciprofloxacin. The second method involves the reaction of levofloxacin with ${\rho}$-chloranilic acid ( ${\rho}$-CA) and norfloxacin with tetracyanoethylene (TCNE) in acetonitrile to give complexes with maximum absorbance at 521 and 333 nm for the two drugs, respectively. Adopting the first procedure, calibration graphs were linear over the range 1- 20 ${\mu}g\;mL^{-1}$ with mean percentage recoveries of 100.41 ${\pm}$ 0.72, 99.99 ${\pm}$ 0.54 and 100.23 ${\pm}$ 0.91 for the theree drugs, respectively. For the second procedure, the concentration ranges were 15-250 ${\mu}g\;mL^{-1}$ for levofloxacin using ${\rho}$-CA and 0.8-16 ${\mu}g\;mL^{-1}$ for norfloxacin using TCNE with mean percentage recoveries of 99.88 ${\pm}$ 0.45 and 100.26 ${\pm}$ 0.68 for the two drugs, respectively. The proposed methods were successfully applied to determine these drugs in their tablet formulations and the results compared favorably to that of reference methods. The proposed methods are recommended for quality control and routine analysis.

• Korean Journal of Materials Research
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• v.14 no.5
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• pp.305-309
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• 2004

Mechanical alloying (MA) of Ti-25.0～37.5at%Si powders was carried out in a high-energy ball mill, and in situ thermal analysis was also made during MA. In order to classify the synthesis behavior of the powders with respect to at%Si, the synthesis behavior during MA was investigated by in situ thermal analysis and X-ray diffraction (XRD). In situ thermal analysis curves and XRD patterns of Ti-25.0～26.1at%Si powders showed that there were no peaks during MA, indicating $Ti_{5}$ $Si_3$ was synthesised by a slow reaction of solid state diffusion. Those of Ti-27.1～37.5at%Si powders, however, showed that there were exothermic peaks during MA, indicating $_Ti{5}$ $Si_3$ and$ Ti_3$Si phase formation by a rapid exothermic reaction of self-propagating high-temperature synthesis (SHS). For Ti-27.1～37.5at%Si powders, the critical milling times for SHS decreased from 38.1 to 18.5 min and the temperature rise, ΔT (= peak temperature - onset temperature) increased form $19.5^{\circ}C$ to $26.7^{\circ}C$ as at%Si increased. The critical composition of Si for SHS reaction was found to be 27.1at% and the critical value of the negative heat of formation of Ti-27.1at%Si to be -1.32 kJ/g.

• Korean Journal of Materials Research
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• v.14 no.5
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• pp.310-314
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• 2004

Mechanical alloying (MA) of Ti-50.0～66.7at%Si powders was carried out in a high-energy ball mill, and in situ thermal analysis was also made during MA. In order to classify the synthesis behavior of the powders with respect to at%Si, the synthesis behavior during MA was investigated by in situ thermal analysis and X-ray diffraction (XRD). In situ thermal analysis curves and XRD patterns of Ti-50.0～59.6at%Si powders showed that there were exothermic peaks during MA, indicating TiSi, $TiS_2$, and $Ti_{5}$ $Si_4$ phase formation by a rapid exothermic reaction of self-propagating high-temperature synthesis (SHS). Those of Ti-59.8～66.7 at%Si powders, however, showed that there were no peaks during MA, indicating any Ti silicide was not synthesised until MA 240 min. For Ti-50.0～59.6at%Si powders, the critical milling times for SHS increased from 34.5 min to 89.5 min and the temperature rise, $\Delta$T (=peak temperature-onset temperature) decreased form $26.2^{\circ}C$ to $17.1^{\circ}C$ as at%Si increased. The critical composition of Si for SHS reaction was found to be 59.6at% and the critical value of the negative heat of formation of Ti-59.6at%Si to be -1.48 kJ/g.

• Journal of Life Science
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• v.14 no.1
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• pp.131-140
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• 2004

T7 bacteriophage gp4 is the replicative DNA helicase that unwinds double-stranded DNA by utilizing dTTP hydrolysis energy. The quaternary structure of the active form of T7 helicase is a hexameric ring with a central channel. Single-stranded DNA passes through the central channel of the hexameric ring as the helicase translocates $5'\rightarrow3'$ along the single-stranded DNA. The DNA unwinding was measured by rapid kinetic methods and showed a lag before the single-stranded DNA started to accumulate exponentially. This behavior was analyzed by a kinetic stepping model for the unwinding process. The observed lag phase increased as predicted by the model with increasing double-stranded DNA length. Trap DNA added in the reaction had no effect on the amplitudes of double-stranded DNA unwound, indicating that the $\tau7$ helicase is a highly processive helicase. Global fitting of the kinetic data to the stepping model provided a kinetic step size of 10-11 bp/step with a rate of $3.7 s^{-1}$ per step. Both the mechanism of DNA unwinding and dTTP hydrolysis and the coupling between the two are unaffected by temperature from $4∼37^{\circ}C$. Thus, the kinetic stepping for dsDNA unwinding is an inherent property of tile replicative DNA helicase.

• Journal of the Korean Geographical Society
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• v.39 no.3
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• pp.321-343
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• 2004

In principal, the original form of Eupchi landscape in Naepo reflects a traditional idea regarding direction as a connection with one's fortune and naturalization strategy of power. In reality, the weight for the landscape inside the castle town was distinct by locality according to the conditions of natural geographies and main function of the castle town. In other words, the traditional Eupchi landscape was shaped under the fixed principles but it was simultaneously reflecting the local temporality and spatiality. As Chosun Dynasty went under the Japanese colonization, Eupchi in the traditional period started to evolve into a modem city. That is to say, the traditional Eupchi as a political place became to change into the center of capital accumulation, stronghold of economy and education, and center of town beyond the function as a place for government and administration. Therefore, the process of change from the landscape of Eupchi to a modem city was a kind of revolution in the form and function, and it was also a very rapid rearrangement of social space. The disparate element of landscape and double social space worked as a vital inertial element in the urban structure of Naepo area until the post independence and evolution of landscape.

• Journal of Korea Foundry Society
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• v.24 no.4
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• pp.231-237
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• 2004

Bake hardenable steel utilizes the phenomenon of strain aging to provide an increase in the yield strength of formed components. An increase of the carbon content will improve the bake hardening response: more solutes are available to pin mobile dislocations and to form the clusters more rapidly. But aging resistance decrease as increasing solute carbon. In order to under-stand the compatibility between bake hardenability and aging resistance. The optimum solute carbon control methods during manufacture should be determined. In this paper, the effect of continuous heat cycle conditions such as soaking temperature, rapid cooling start temperature, cooling rate on BH(Bake Hardenability), AI(Aging Index), YP-El(Yield Point Elongation) and other mechanical properties have been investigated. and following results were obtained. In the case of soaking temperature, BH increases with higher soaking temperature because of NbC $dissolution(830^{\circ}C)$, Therefore the solute carbon and BH at $850^{\circ}C$ and $870^{\circ}C$ are higher than these at $810^{\circ}C$. But BH at $870^{\circ}C$ is a little lower than that at $850^{\circ}C$ owing to the ferrite grain size. The measurement of amount of dissolution C using IFT(Internal Friction Test) can explain the relation of solute carbon and BH.

• Korean Journal of Human Ecology
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• v.21 no.3
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• pp.551-565
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• 2012

The primary goal of this study was to provide a systematic methodology of utilizing 3D technology for tight-fit performance sportswear using information of skin deformation in various posture. Technical tools used in this study are Cyberware whole body scanner, RapidForm2004, 2C-AN 3D pattern development program, and YukaCAD. Analysis of the 3D skin deformation while knee joint was bent from $0^{\circ}$ to $60^{\circ}$ revealed that the length of dermatomes L4 was remained consistent during knee bending. Therefore, L4 was chosen as a major cutting line. To develop a highly ergonomic pattern, replicas of static and dynamic postures were developed and integrated using two methods, one is morphing method (Sqirlz Morph), and the other is AutoCAD. Experimental tight-fit garments called 'Derm-Mov Pattern' was designed using dematomes L4, L2, and inner line under knee and compared with four other patterns. As results, AutoCAD was appropriate as a integrating method of various postures. In wear test, 'Derm-Mov Pattern' was rated high (p < .001), in terms of pressure comfort especially around front crotch area. However, wear sensation was not signipicantly different in other area due to highly extensible property of materials. Pressure distribution was relatively even in these experimental garments.

• Journal of Korea Association of Health Promotion
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• v.2 no.3
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• pp.31-46
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• 2004

Owing to continuous economic growth, an increased standard of living, and improvements to health care in Korea, the life expectancy of Koreans rose from 69.0years in 1985 to 71.3 years in 1990 It continued to rise throughout the 1990s, and, by2002, had reached 76.5 years for the general population and 80.0 years for Korean females. Similarly, the percentage of the Korean population that is 65 years of age or older Increased from 3.1 In 1970 to 7.1 In 2000, and is expected to reach approximately14.0 in 2019. Thus, according to this estimate, Korea will have evolved from an 'aging society 'to an "aged society" in only 19 years. In the case of other countries, this same transformation has generally taken 2 to 5 times longer. One of the major issues related to Korea's rapid1y aging population relates to the health problems of the elderly According to the 2002 National Health Survey Report,87.6 percent of the elderly were reported to have at least one chronic disease. In other words, almost 9 out of evert 10 elderly persons in Korea were suffering from a chronic illness. This, clearly, places a significant economic burden on Korean society in the form of increased health care costs. This paper examines the increasing prevalence of chronic diseases within Korea's rapidly aging population and offers some possible short- and long-term solutions to cope with the increased burden being placed on Korea's health care system. These Include the basic services at local health centers for the elderly and the national life-long health promotion programs that aim to correct unhealthy behavior, such as smoking, the excessive use of alcohol, and poor eating and exercise habits.

• Macromolecular Research
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• v.12 no.2
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• pp.172-177
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• 2004

We have studied the lamella-level morphology of poly(ethylene terephthalate) (PET)/polycarbonate (PC) blends using small-angle X-ray scattering (SAXS). Measurements were made as a function of the holding time in the melt. We determined the morphological parameters at the lamellar level by correlation function analysis of the SAXS data. An increased amorphous layer thickness was identified in the blend, indicating that some PC was incorporated into the interlamellar regions of PET during crystallization. The blend also exhibits a larger lamella crystalline thickness (l$\sub$c/) than that of pure PET. A possible reason for the increase in l$\sub$c/ is that the inclusion of the PC molecules in the interlamellar regions causes an increase in the surface free energy of folding. At the early stage of isothermal crystallization, we observed a rapid drop in the value of l$\sub$c/ in the blend; this finding indicates that a relatively large fraction of secondary crystals form during the primary crystallization. In contrast, the value of l$\sub$c/ for the sample that underwent a prolonged holding time increased with time in the secondary crystallization-dominant regime; this observation suggests that the disruption of chain periodicity, which results from transesterification between the two polymers, favors the development of fringed micellar crystals that have larger values of l$\sub$c/ rather than the development of normal chain-folded crystals.

• The Journal of Pediatrics of Korean Medicine
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• v.20 no.3
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• pp.161-169
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• 2006

Objectives : Patients who visit oriental medical hospital for growth treatment are increasing. So we aimed to classify the tendency of the patients. Methods : We studied 231 patients who visited Oriental medical hospital for growth treatment from January 2004 to August 2005. We classified sex ratio, height percentile, symptom form of the Oriental medicine, age ratio and developed complication of patients. We used X-ray, endoscope for nasal cavity, blood sample, the Standard Growth Table made by the Korean Association of Pediatrics, 1998. Results : The results which were classified as follows; boys were 50.2 percentile, girls were 49.8 percentile. The classification according to age stage resulted as follows; infant stage 1.3 percentile, preschool age 13.4%, school age 28.6%, rapid growth stage 22.9 percentile, puberty 33.8 percentile. The classification according to height percentile resulted as follows; 3 percentile or under 12.1%, 25 percentile or under 48.9%, 50 percentile or under 25.6%, 75 percentile or under 10.8%, 75 percentile excess 2.6%. The classification according to disease resulted as follows; paranasal sinusitis 12.1 percentile, allergic rhinitis 10 percentile, atopic dermatitis 5.6 percentile, nocturia 3 percentile, convulsion or tic disorder 2.2 percentile, precocious puberty 1.3 percentile, Tuner syndrome 0.9 percentile, developmental disability 0.4 percentile. Conclusions : Sex ratio of children patients who visited Orienatal medical hospital were nearly the same. 13.4% of hospital visit children patients were taller than average. Most of the male children patients were school ages while the female were in puberty. 35.5% of them have developed complication as follows; paranasal sinusitis, allergic rhinitis, atopic dermatitis, nocturia, convulsion or tic disorder, precocious puberty, Tuner syndrome and developmental disability.