• KCI Concrete Journal
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• v.11 no.3
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• pp.127-140
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• 1999

In this paper, a microscopic analysis of prefinitelv strained cement paste specimen was carried out. The microscopic behavior of concrete under triaxial stress must be fully understood in order to explain the additional ductilitv that comes from lateral confinement and to get microstructural information in large deformed and large strained concrete. The so-called "tube-squash" test was applied to achieve enormously high shear and deviatoric strain of concrete under extremly high pressure without fracture. Then, microscopic analyses by focusing on hydration and microstructure of Prefinitely strained cement paste were carried out on cored-out deformed and virgin (undeformed) cement paste specimens : the first specimen being 40 days old, the second one being one year old. The microscopic analysis bv Field Emission Scanning Electronic Microscope (FESEM) was carried out for comparison between the specimens after 40 days and those arter one year. For one year old specimens, X-Ray Diffractometer (XRD) analysis, Energy Dispersive x-rav Spectrometer (EDS) analysis, and Differential Thermal Analysis/Thermo-Gravitv (DTA/TG) analysis were also carried out to study the hydration and the microstructures of prefinitely strained cement paste specimen by focusing on the methodologies of their microscopic analyses. analyses.

• Journal of Pharmaceutical Investigation
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• v.27 no.2
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• pp.145-151
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• 1997

Hexane, chloroform, methanol and water extracts of Paeoniae Radix were tested on the experimentally induced hypercholesterolemia in rats for lowering effect of serum lipoprotein contents. Hyperlipidemia was induced on male Wistar rats by feeding high cholestetrol diet for 7 days. Serum lipid profile was verified on these rats by measuring total cholesterol (TC), triglyceride (TG), high density lipoprotein cholesterol (HDL), and low density lipoprotein cholesterol (LDL). Then, the diet was changed to normal. At the same time, hexane, chloroform, methanol and water extract of Paeoniae Radix were given orally on daily basis, and the changes in the serum lipid profile were assessed for 4 weeks. Methanol extract of Paeoniae radix decreased TC level at 1, 2, and 4 week point significantly, and water extract decreased TC level at 4 week point significantly comparing with the control group.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.28 no.1
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• pp.214-224
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• 2002

High concentrated $TiO_2$ nano colloids were synthesized by sol-gel method. Reactions were performed in $TiCl_4$/HCl/$H_2O$ aqueous solution and the conditions of particles such as shape, size and aggregation, etc. were controlled by polymerization and adsorption of acrylamide in surface of $TiO_2$ nano particles. And also, aminopropyltriethoxysilane was added instead of acrylamide and compared each other. The prepared colloids were well dispersed and showed the strong absorption peaks at 350nm-370nm which is blue shifted to 20-30nm, compared to macro particles. The obtained techniques from $TiO_2$ nato colloids synthesis were utilized in coating on boron nitride powders which are nonpolar and isoelectronic materials of carbon. Their surface morphology, structure, thermal stability and U. V absorption chracteristics were examined by SEM(Scanning Electron Microscopy), XRD(X-ray diffraction), TG/DTA(Thermogravimetric and Differential Thermal Analysis), UV-VIS(Ultraviolet-Visible Spectroscopy).

• Elastomers and Composites
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• v.53 no.4
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• pp.202-206
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• 2018

Five solution styrene butadiene rubber/neodymium butadiene rubber (SSBR/NdBR) composites were manufactured using different ratios of SSBR and NdBR. In this study, the composites were reinforced with NdBR and silica to confirm the physical properties of SSBR used for treads of automobile tires and the dispersibility with silica. The morphologies of the rubber composites were observed using field-emission scanning electron microscopy (FE-SEM). The crosslinking behaviors of the composites were tested using a rubber process analyzer (RPA), and the abrasion resistances were tested using a National Bureau of Standards (NBS) abrasion tester. The hardness values, tensile strengths, and cold resistances of the composites were also tested according to ASTM standards. Increased NdBR content yielded composites with excellent crosslinking properties, abrasion resistances, hardnesses, tensile strengths, and cold resistances. The crosslinking point increased due to the double bond in NdBR, thereby increasing the degree of crosslinking in the composites. The NdBR-reinforced composites exhibited excellent abrasion resistances, which is explained as follows. In SSBR, a breakage is permanent because a resonance structure between styrene and SSBR forms when the molecular backbone is broken during the abrasion process. However, NdBR forms an additional crosslink due to the breakdown of the molecular backbone and high reactivity of the radicals produced. In addition, the low glass transition temperature (Tg) of NdBR provided the rubber composites with excellent cold resistances.

• Textile Coloration and Finishing
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• v.34 no.3
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• pp.197-206
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• 2022

The purpose of this study was to confirm the optimal spinning conditions for PLA (Polylactic acid) as a fiber forming polymer. According to the melt spinning test results of PLA, the optimal spinning temperature was 258℃. However, it needs to note that relatively high pack pressure was required for spinning at 258℃. At an elevated temperature, 262℃, mono filament was broken easily due to hydrolysis of PLA at a higher temperature. In case of fiber strength, it was confirmed that the draw ratios of 2.7 to 3.3 were optimal for maximum strength of melt spun PLA. Above the draw ratio, 3.3, the strength of the PLA fibers was lowered. It was presumed that cleavage of the PLA polymer chain over maximum elongation. The heat setting temperature of GR (Godet roller) showed that the maximum strength of the PLA fibers was revealed around 100℃. The degree of crystallinity and the strength of the PLA fibers were decreased above 100℃. The optimal take-up speed (Spinning speed) was around 4,000m/min. Thermal analysis of PLA showed 170℃ and 57℃ as Tm (melting temperature) and Tg (glass transition temperature), respectively.

• Proceedings of the Ginseng society Conference
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• 1993.09a
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• pp.113-118
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• 1993

The lowering effect of cholesterol in Sprague Dawley rats was investigated with panaxydol which was purified from the petroleum ether soluble fraction(PESF) of Korean red ginseng. The level of total cholesterol(TC), Triglyceride(TG) and low density lipoprotein(LOL)-cholesterol in serum was reduced by $48\%,\;47\%\;and\;41\%,$ respectively while high density lipoprotein(HDL)-cholesterol was in creased up to $29\%$ as compared with their control values when the panaxydol(20 umoles. 5 mq/kq/day) was adminstered by intraperitoneal rout for 3 consecutive days along with a $1\%$ cholesterol diet. The hepatic ester cholesterol content which was increased in proportion to the cholesterol content of the diet in the control, clearly decreased with panaxydol administration to about $40\%$ regardless of the two diet cholesterol content. $1\%\;or\;2\%.$ A threshold of supression on the serum lipid levels in both administration routes was observed: the maximium suppression in i.p. and p.o. administration was observed to be at 5mq/kq b.w. and in the range of 50 - 100 mg/kg b.w., respectively. Panaxydol may reduce serum lipid and cholesterol levels by inhibiting cholesterol absorption and/or by modulating the cholesterol metabolism. at least in part.

• Journal of Korean Medicine Rehabilitation
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• v.24 no.3
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• pp.1-9
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• 2014

Objectives The aim of this study was to investigate the effects of acupuncture on weight loss, food intake, lipid metabolism, adipogenesis. Methods Four week-old C57BL/6J mice acclimatized to the laboratory environment for 1 week were allocated into four groups of 6~8 mice each: normal diet group, high fat diet group, high fat diet group and treated with acupuncture at HT7, high fat diet group and treated with acupuncture at ST36 for 90days. High fat diet group was used to control group. Results 1) Body weight, food intake of the ST36, HT7 groups decreased compared with those of control group. ST36 group was more effective with body weight decrease, and HT7 group was more effective with food intake decrease. 2) NEFA, TG, TC, ALT, AST of the ST36, HT7 groups decreased compared with those of control group. ST36 group was more effective. 3) The expression of SREP-1c, SREBP-2 of the ST36 group decreased compared with those of control group. These decreased rates were statistically significant. SREBP-2 of the HT7 group decreased significantly compared to the control group. 4) LXR, FAS, SCD of the ST36 group decreased significantly compared with control group. 5) p-ACC, HMGCR of the ST36 group decreased significantly compared with those of control group. HMGCR of the HT7 group decreased significantly compared with control group. Conclusions These results suggest that ST36, HT7 acupuncture may be used prevent or treat the obesity induced by high fat diet.

• Korean Journal of Materials Research
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• v.21 no.5
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• pp.283-287
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• 2011

As the performance of microelectronic devices is improved, the use of copper as a heat dissipation member is increasing due to its good thermal conductivity. The high thermal conductivity of copper, however, leads to difficulties in the joining process. Satisfactory bonding with copper is known to be difficult, especially if high shear and peel strengths are desired. The primary reason is that a copper oxide layer develops rapidly and is weakly attached to the base metal under typical conditions. Thus, when a clean copper substrate is bonded, the initial strength of the joint is high, but upon environmental exposure, an oxide layer may develop, which will reduce the durability of the joint. In this study, an epoxy adhesive formulation was investigated to improve the strength and reliability of a copper to copper joint. Epoxy hardeners such as anhydride, dihydrazide, and dicyandiamide and catalysts such as triphenylphosphine and imidazole were added to an epoxy resin mixture of DGEBA and DGEBF. Differential scanning calorimetry (DSC) analyses revealed that the curing temperatures were dependent on the type of hardener rather than on the catalyst, and higher heat of curing resulted in a higher Tg. The reliability of the copper joint against a high temperature and high humidity environment was found to be the lowest in the case of dihydrazide addition. This is attributed to its high water permeability, which led to the formation of a weak boundary layer of copper oxide. It was also found that dicyandiamide provided the highest initial joint strength and reliability while anhydride yielded intermediate performance between dicyandiamide and dihydrazide.

• Journal of Nutrition and Health
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• v.18 no.1
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• pp.29-35
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• 1985

This study was designed to evaluate the effects of tocopherol supplementation on serum $HDL_{2}$ and $HDL_{3}$ subfraction and lipoprotein pattern of young rabbits fed the different levels of dietary polyunsaturated fatty acids. White male rabbits with an average bo요 weight of 90kg were assigned into 4 groups : LP( Low PUFA) ; HP( High PUFA) ; LPT( Tocopheror added to LP), HPT(Tocopherol added to HP) by feeding safflower oil or coconut oil at loft( w/w )in addition to thew diet with or without tocopherol for 4 weeks. HDL-Chol and HDL subfractions were determined by polyanionic precipitation method, and the relative amount of lipoprotein by electrophoresis. Serum total cholesterol and TG wer slightly lowered in the group of high PUFA diet and its effect was more in the case of tocopherol supplemented. HDL-Chol level was reduced in the high PUFA diet with or without tocopherol, but overall, HDL-Chol level was not influenced by tocopherol addition and also no significant change in lipoprotein pattern when tocopherol added to the HP diet. $HDL_{2}$ level was increased in HPT group but not in LPT group when tocopherol was added to each HP and LP group, respectively. $HDL_{3}$ levels of both LP and HP groups were reduced with tocopherol supplement, but the reduction was less in the high PUFA groups so that $HDL_{2}$ : $HDL_{3}$ ratio of HP was rather close to that of LP, but it was increased when tocopherol supplemented to the HP diet. Therefore, high PUFA diet could improve the anti atherogenic factor when tocopherol supplemented.

• The Journal of Korean Medicine
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• v.27 no.2 s.66
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• pp.14-22
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• 2006

Objectives : The purpose of this study was to find the prevalences and risk factors of the metabolic syndrome according to Sasang constitution. Methods : The medical records of 364 subjects who had taken health examinations and diagnosis of Sasang constitution from January to June of 2003 at a health examination center of a hospital in Seoul were reviewed. The prevalences and the risk factors of the metabolic syndrome according to Sasang constitution were compared and analyzed. Results : 1) Among the 364 subjects, 88 (24.2%) were Soeumin, 101 (27.7%) were Soyangin, and 175 (48.1%) were Taeumin. 2) The prevalences of high WC, high TG, low HDL-c, high BP and high FBS of Taeumin were significantly higher than those of the other constitutions (p-value < 0.05). 3) The prevalence of the metabolic syndrome of Taeumin, Soyangin, and Soeumin were 46.3%, 16.8% and 9.1% respectively. The rates were significantly different according to Sasang constitution (p-value < 0.001). 4) Taeumin had higher risk of high WC than Soeumin (adjusted OR : 3.83, 95% CI : 1.19-12.29) and higher risk of high FBS than Soeumin (adjusted OR: 5.93,95% CI : 1.11-31.77). 5) Taeumin had higher risk of the metabolic syndrome than Soeumin (adjusted OR : 3.40, 95% CI : 1.25-9.23). Conclusions : There were significant differences in the prevalence of metabolic syndrome according to Sasang constitution. Sasang constitution was identified as an independent risk factor of metabolic syndrome.