• Transactions of Materials Processing
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• v.18 no.1
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• pp.45-51
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• 2009

Shape memory alloy has been used to improve the tensile strength of composite by the occurrence of compressive residual stress in matrix using its shape memory effect. In order to fabricate shape memory alloy composite, TiNi alloy fiber and Al2024 sheets were used as reinforcing material and matrix, respectively. In this study, TiNi/Al2024 shape memory alloy composite was made by using hot press method. In order to investigate bonding condition between TiNi reinforcement and Al matrix, the micro-structure of interface was observed by using optical microscope and diffusion layer of interface was measured by using Electron Probe Micro Analyser. And the mechanical properties of composite with three parameters(volume fraction of fiber, cold rolling amount and test temperature) were obtained by tensile test. The most optimum bonding condition for fabrication the TiNi/Al2024 composite material was obtained as holding for 30min. under the pressure of 60MPa at 793K. The strength of composite material increased considerably with the volume fraction of fiber up to 7.0%. And the tensile strength of this composite increased with the reduction ratio and it also depends on the volume fraction of fiber.

• School Mathematics
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• v.11 no.3
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• pp.463-477
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• 2009

Decimal Fraction with a significant meaning is being treated for long periods, from elementary school to high school. It is necessary to consider in a course of guidance about various aspects of decimal Fraction first of all in order that student understand well about the concert of it. If you overlook guidance of various means of decimal Fraction, Previously learned number system is limited understand of Decimal Fraction concept or meaning of Decimal Fraction limited to the one is difficult to calculate the Decimal Fraction, even can weaken understand of Real Number. Accordingly, in this study, we would like to separate meanings of the Decimal Fraction, focusing on the role and function of the Decimal Fraction in various situations used the Decimal Fraction. Based on this, we analyzed and criticized how to introduce the Decimal Fraction in elementary school textbooks according to the 7th curriculum.

• KSBB Journal
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• v.29 no.1
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• pp.29-35
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• 2014

In this study, antioxidant and antimicrobial activities of ethanolic crude extract and its five different solvent subfractions (namely, ethyl acetate fraction, n-butanol fraction, chloroform fraction, n-hexane fraction and the aqueous fraction) from a mixture of four different medicinal herbs (Galla rhois, Achyranthes japonica Nakai, Terminalia chebula Retz and Glycyrrhiza uralensis) were investigated. Among all the tested mixture combination of four medicinal herbs, 5:3:1:1 ratio of Galla:Achyranthes : Terminalia : Glycyrrhiza had the best antimicrobial effects against four strains of microorganisms (Staphylococcus aureus, Staphylococcus epidermidis, Pseudomonas aeruginosa and Escherichia coli) and exhibited the highest DPPH radical-scavenging activity. Further sub-fractions with solvents were screened for antioxidant and antimicrobial activities. Antioxidant activity in order was ethyl acetate fraction > n-butanol fraction > chloroform fraction > nhexane fraction > aqueous fraction. The n-butanol extracted fraction showed the highest level of antimicrobial activity in com- parison to other fractions. In addition, all those fractions did not show any cytotoxicity against human skin cell CCD-986sk. These results suggest that 5:3:1:1 combination extracts of medicinal herbs (Galla : Achyranthes : Terminalia : Glycyrrhiza) may be potentially used as a safe natural antimicrobial preservative.

• Food Science and Biotechnology
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• v.15 no.5
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• pp.672-676
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• 2006

The aim of this study is to evaluate the antioxidant, antimicrobial, and antitumor activities of various concentrations of partially purified substance(s) from green tea seed (Camellia sinensis L.). The total polyphenol contents of each fraction (non-adsorption fraction: F-1, fraction eluted with 40% methanol: F-2, and fraction eluted with 100% methanol: F-3) purified by Diaion HP-20 column chromatography were, in the increasing order: F-1 (3.7 mg tannic acid equivalents, TAB/g) < F-3 (23.2 mg TAB/g) < seed extracts (26.2 mg TAB/g) < F-2 (42.7 mg TAB/g). The scavenging activities toward the 1,1-diphenyl-2-picyrylhydrazyl (DPPH) radical were, in decreasing order: F-2 (93.3%) > butylated hydroxytoluene (BHT; 89.8%) > ascorbic acid (89.3%) > leaf extracts (70.3%) > F-3 (15.9%) > seed extracts (15.8%) > F-1 (14.8%) at a 0.1% concentration. In studies on antimicrobial activities, the results indicate that the growth of yeast (Candida albicans KCCM 11282 and Cryptococcus neoformans KCCM 50544) was inhibited more so than that of other fungi (Alternaria alternate KCTC 6005 and Rhizoctonia solani). In addition, it appears that the antitumor activities of the F-1, F-2, and F-3 fractions at a concentration of $50\;{\mu}g/mL$ showed 6, 7, and 23% growth inhibition of the HEC-1B cell line, 14, 11, 82% inhibition of the HEP-2 cell line, and 8, 16, and 81% inhibition of the SK-OV-3 cell line, respectively. Overall these results indicate that the antioxidant activity is greatest in the F-2 fraction, and the antimicrobial and antitumor activities are greatest in the F-3 fraction.

• Journal of Veterinary Clinics
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• v.9 no.2
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• pp.433-449
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• 1992

Total CPK activities and CPK isoenzymes fractions of the sera and tissues were examined to obtain the physiological basic data of ruminant available in veterinary clinical practice. For the sera total CPK activities and CPK isoenzymes fractions, total 39 clinically healthy Korean native goats (3 to 10 months old, IS of female and 18 of male) and 6 of Korean native goats (1 to 2 years old, 3 of female and 3 of male) were used. Seventeen Korean native cattle (3 to 6 years old, 10 of female and 7 of male) and 27 Holstein-Friesian cattle (2 to 8 months old, 7 of female and 3 to 12 years old, 20 of female) were also examined for the sera total CPK activities and CPK isoenzymes fractions. For the total CPK activities and CPK isoenzyme fractions, 3 of female Korean native goats (7 months old), 3 of female Korean native cattle (2 years old) and 3 of dairy cattle (2 years old, 2 of female and 1 of male) were used. The tissues examined were the cerebrum (2 of Korean native cattle), spinal cord (1 of Korean native cattle), heart, lung, diaphragm, reticulum, liver, spleen, kidney, jejunum. colon and femoral muscle. The results obtained were as follows : 1. In Korean native goats less than 1-year-old. serum total CPK activities were 67.8${\pm}$17.7(39.0~96.5) IU/$\ell$ in female and 63.4${\pm}$19.0(28.7~94.4) IU/$\ell$ in male. Further they were 67.0${\pm}$5.3(59.5~70.7) IU/$\ell$ and 54.5${\pm}$11.1(39.1~69.4) IU/$\ell$ in female and male Korean native goats over 1-year-old, respectively. Serum total CPK activities of female were slightly higher than those of male. Significance between age and sex was not found. 2. Serum total CPK activities were 56.8${\pm}$19.7(27.6~90.5) IU/$\ell$ and 65.6${\pm}$10.8(52.8~78.0) IU/$\ell$ in female and male Korean native adult cattle, respectively, Serum total CPK activities of male were slightly higher than those of female, but they were not significant 3. Serum total CPK activities we,e 72.5${\pm}$8.2(57.2~83.2) IU/$\ell$ and 60.8${\pm}$12.5(42.7~80.6) IU/$\ell$ in calves and adult of dairy acttle, respectively. Serum total CPK activities of calves were significantly higher than those of adult(p<0.05). 4. In Korean native goats less than 1-year-old, serum CPK isoenzymes fractions were high with decreasing order of MM>MB>BB and MM>BB>MB in female and male, respectively. Further they were high with decreasing order of MM>MB>BB and MM>B8>MB in female and male Korean native goats over 1-year-old, respectively. The main fractions of CPK isoenzymes were MM in sera of Korean native goats. 5. Serum CPK Isoenzyme fractions were high with decreasing order of MM>MB>BB In both female and male of Korean native cattle. The main fraction among them was MM. 6. Serum CPK isoenzymes fractions were high with decreasing order of MM>BB>MB in both calves and adult of dairy cattle. The main fraction among them was MM. 7. Total CPK activities were high with decreasing order of the femoral muscle>kidney>reticulum>diaphragm>liver>spleen>heart>colon>lung>jejunum in Korean native goats. 8. Total CPK activities were high with decreasing order of the spinal cord >cerebrum>femoral muscle>reticulum>kidney>liver>spleen>diaphragm>lung>colon>heart>jejunum in Korean native cattle. 9. Total CPK activities were high with decreasing order. of the femoral muscle >liver>retoculum>kidney>heart>colon>lung>spleen>jejunum>diaphrasm in dairy cattle. 10. The pattern of the cardiac CPK isoenzymes fractions was identical in Korean native goats, Korean native cattle and dairy cattle. They were high in the order of MM>MB without BB fractions and the main fraction was MM. 11. The pattern of the pulmonary CPK isoenzymes fractions was the same Korean native goats, Korean native cattle and dairy cattle. They were high with decreasing order of MM>MB>BB and the main fraction among them was MM. 12. The pattern of CPK isoenzymes fractions of the diaphragm was Identical in Korean native goats and Korean native cattle. They were high with decreasing order of MM >BB >MB except dairy cattle (MM>MB>BB) but the main fraction among them was MM. 13. The pattern of the reticular CPK isoenzymes fractions was identical in Korean native cattle and dairy cattle. They were high with decreasing order of BB >MM >MB except Korean native goats(BB>MB>MM) but the main, fraction among them was BB 14. The pattern of the hepatic CPK isoenzymrs fractions was identical in Korean native cattle and dairy cattle. They were high with decreasing order of MB >BB >MM except Korean native goats(MB>MM>BB)but the main fraction was MB. 15. The splenic CPK isoenzymes fractions showed different pattern. They were high with decreasing order of MB>BB>MM, MM>BB>MB and BB>MB>MM in Korean native goats, Korean native cattle and dairy cattle, respectively. The main fraction among them was different from each other. 16. The pattern of the renal CPK isoenzymes fractions was identical in Korean native cattle and dairy cattle. They were high with decreasing order of MM >MB>BB except Korean native goats(BB>MB>MM). 17. The CPK isoenzymes fractions of the Jejunums showed different pattern. They were high with decreasing order MM>MB>BB, MM>BB>MB and BB>MM>MB in Korean native goats, Korean native cattle and dairy cattle, respectively. The main fractions were MM In Korean native goats and Korean native cattle, and BB in dairy cattle. 18. The colonic CPK isoenzymes fractions showed different pattern. They were high with decreasing order of MM>MB>BB, MM>BB>MB and BB>rrfB>MM in Korean native goats, Korean native cattle and dairy cattle, respectively. The main fractions were MM in Korean native goats and Korean . native cattle, and BB in dairy cattle. 19. The cerebral CPK isoenzymes fractions were high with decreasing order of BB >MM without MB detected in Korean native cattle and those of spinal cord were high with decreasing order of BB >MM >MB. The main fractions in both cerebrum and spinal cord were BB.

• Journal of Educational Research in Mathematics
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• v.15 no.3
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• pp.287-313
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• 2005

The decimal fraction concept plays an important role in understanding the real number which is one of the major concepts in school mathematics. In the school mathematics of Korea, the decimal fraction is treated merely as a sort of name of the common fraction, while many other important aspects of the decimal fraction concept are ignored. In consequence students fail to understand the decimal fraction concept properly, and merely consider it as a kind of number for formal computation. Preceding studies also identified students' narrow understanding of the decimal fraction concept. But none of them succeeded in clarifying the essences of the decimal fraction concept, which are crucial for discussing the didactical problems of it. In this study we attempted a didactical analysis of the decimal fraction concept and disclosed the roots of didactical problems and presented measures for its improvement. First, we attempted a phenomenological analysis of the decimal fraction concept and extracted 9 elements of the decimal fraction concept. Second, we has analyzed of the essence of the decimal fraction concept more clearly by relating it to the situations where it functions and its representations. For this we tried to construct the conceptual field of the decimal fraction. Third, we categorized he developmental levels of the decimal fraction concept from the aspect of external manifestation of the internal order. On the basis of these results, we attempted hierarchical structuring of the elements of the decimal fraction concept. And using the results of such a didactical analysis on the decimal number concept we analyzed the mathematics curriculum and textbooks of our country, investigated levels of students' understanding of the decimal fraction concept, and disclosed related problems. Finally we suggested directions and measures for the improvement of teaching decimal fraction concept.

• Coupled systems mechanics
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• v.5 no.3
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• pp.269-283
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• 2016

A two new high-order shear deformation theory for bending analysis is presented for a simply supported, functionally graded plate with porosities resting on an elastic foundation. This porosities may possibly occur inside the functionally graded materials (FGMs) during their fabrication, while material properties varying to a simple power-law distribution along the thickness direction. Unlike other theories, there are only four unknown functions involved, as compared to five in other shear deformation theories. The theories presented are variationally consistent and strongly similar to the classical plate theory in many aspects. It does not require the shear correction factor, and gives rise to the transverse shear stress variation so that the transverse shear stresses vary parabolically across the thickness to satisfy free surface conditions for the shear stress. It is established that the volume fraction of porosity significantly affect the mechanical behavior of thick function ally graded plates. The validity of the two new theories is shown by comparing the present results with other higher-order theories. The influence of material parameter, the volume fraction of porosity and the thickness ratio on the behavior mechanical P-FGM plate are represented by numerical examples.

• Biomolecules & Therapeutics
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• v.13 no.1
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• pp.26-31
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• 2005

The present study examined effects of a water-soluble fraction from mulberry leaves (ML water fraction) on the circulatory and autonomic nervous systems, which were compared with those of acetylcholine (ACh) used as a reference drug in order to elucidate its mechanism of action. Intravenous administration of ACh or a ML water fraction produced temporary depressor and tachycardiac responses in a dose-dependent manner in unrestrained, conscious Sprague-Dawley rats. The systemic hemodynamic effects of ACh and a ML water fraction were almost completely blocked by pretreatment with atropine, a muscarinic antagonist. The depressor responses to ACh and a ML water fraction were slightly enhanced and prolonged by pretreatment with neostigmine, an anticholinesterase, whereas the tachycardiac responses were remarkably blocked by pretreatment with pentolinium, a ganglionic blocking agent. In vitro experiments using the ileum isolated from rats showed that ACh and a ML water fraction increased ileal contractility in a dose-dependent manner. The increases in ileal contractility were also completely abolished in the presence of atropine. Finally, the specific binding of [$^3H$]quinuclidinyl benzilate, a muscarinic antagonist, to rat cortical synaptic membranes was inhibited by a ML water fraction in a concentration-dependent manner with an IC$_{50}$ value of 9.5 mg/ml. The results suggest that the effects of a ML water fraction are mediated through direct stimulation of muscarinic cholinergic receptors by unknown cholinomimetic substance(s) contained in that fraction.

• Journal of Acupuncture Research
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• v.19 no.2
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• pp.1-13
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• 2002

Objective ; In order to study the effect of Acanthopanax senticosus(AS) aqua-acupuncture manufactured with water soluble fraction and ether soluble fraction on the streptozotocin induced diabetic rats Methods ; The fractions of AS aqua-acupuncture were carried out on corresponding bilateral loci of Bisu(BL20) everyday for 4 weeks. The experimental animals were divided into control group and AS groups(AS water fraction group and AS ether fraction group). Thereafter the levels of serum glucose, total choleterol, HDL, triglyceride, AST, ALT, creatinine, BUN, urinary albumin excretion, index of kidney hypertrophy, heart rate, mean blood pressure and fibronectin in glomeruli and tubular cells were measured. Results ; The increased serum total cholestrol, triglyceride levels, HDL and urinary albumin excretion, the index of kidney hypertrophy, the mean blood pressure and the amount of fibronectin in glomeruli and tubular cells were significantly decreased in the AS groups, showing more significant decrease in the AS water fraction group as compared with the control group. In the serum ALT, AST, creatinine and BUN levels, there were no significant changes in the AS groups as compared with the control group. Conclusion ; According to the above results, it reveals that Acanthopanax senticosus water soluble and ether soluble fraction have the antidiabetic effect, the antilipidemic effect and the inhibitory effect of renal damage. Also, the results showed that Acanthopanax senticosus water soluble fraction is more effective than ether soluble fraction.

• Journal of Educational Research in Mathematics
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• v.19 no.1
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• pp.25-43
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• 2009

The fraction concept consists of various meanings and is one of the abstract and difficult in elementary school mathematics. This study intends to find out the implication for introducing the fraction concept by comparing mathematics textbooks of Korea and Singapore. Both countries' students peformed well in recent TIMMSs. Some implications are as follows; The term 'equal' is not defined and the results of various 'equal partitioning' activities can not easily examined in Korea's mathematics textbook. And contexts of introducing fractions as a quotient and a ratio are unnatural in Korea's mathematics textbook in comparison with Singapore's mathematics textbook. So these ideas should be reconsidered in order to seek the direction for improvement of it. And Korea's textbooks need the emphasis on the fraction as a measure and on constructing fraction concept by unit fraction.