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        검색결과 2,191

        481.
        2015.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Since Korean ancient times, powder of Rosa rugosa Thunberg has been used as a folk remedy. This study was conducted to verify the effects of Rosa rugosa Thunberg powder on in vitro antioxidant properties and serum lipid levels of high-fat diet-induced mice from a nutritional viewpoint. In the case of Rosa rugosa Thunberg powders, measurement of TPC, ABTS radical scavenging activity of trolox, DPPH radical scavenging activity, and measured value of FRAP were higher in ethanol extract than water extracts. For LDL-cholesterol concentration, mice fed 10% powder of Rosa rugosa Thunberg with high-fat diets showed a high numerical value compared with other groups (p<0.05). When testing for triglyceride concentrations in blood, mice fed 10% and 20% powder of Rosa rugosa Thunberg with high-fat diets showed the lowest numerical values (p<0.05). When testing for blood insulin concentrations, the high-fat diet group showed higher levels than compared to the control group (p<0.05). When testing for blood leptin concentrations, the high-fat diet group was 5.88±3.53 ng/dL, whereas mice fed 10% powder of Rosa rugosa Thunberg with high-fat diets showed a blood leptin level of 10.36±5.96 ng/dL (p<0.05). Therefore, results prove that powder of Rosa rugosa Thunberg reduces triglyceride concentrations in the blood, and could be used as an excellent natural antioxidant in the future.
        4,000원
        482.
        2015.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The study was conducted to evaluate the effects of Hericium erinaceum Powder (HEP) on the quality characteristics of Jook. The proximate composition of HEP was as follows: moisture, 6.10%; crude protein, 32.69%; crude lipid, 4.63%; crude ash, 11.40%; and carbohydrates, 45.18%. Each sample contained 3, 6, and 9% Jook of Hericium erinaceum Powder (JHEP) compared to the control and their physicochemical properties assessed. As the level of HEP increased, there was a significant decrease in pH (p<0.05) and significant increase in total acidity (p<0.001). In addition, L and a values decreased, whereas b value increased with increasing addition of HEP. The Jook showed lower spreadability and higher viscosity values as its content increased. According to the results, addition of HEP positively affects the quality characteristics of Jook.
        4,000원
        483.
        2015.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was conducted to promote the utilization of fish paste containing four different amounts (0%: control, 2, 4, and 6%) of cheonggukjang powder. For Hunter color values, L values of samples decreased as concentration of cheonggukjang powder increased, and a and b values increased. Folding tests for all samples showed good flexibility. In the texture meter test, hardness, cohesiveness, and springiness increased according to increasing concentrations of cheonggukjang powder. However, gumminess and brittleness of fish paste were reduced upon addition of cheonggukjang powder. In the sensory evaluation, fish paste prepared with 2% cheonggukjang powder was more preferred over other fish pastes. This study suggests that addition of 2% cheonggukjang powder to fish paste could be a good way to increase cheonggukjang powder without decreasing texture acceptability.
        4,000원
        484.
        2015.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of this study was to investigate the quality characteristics of cookies containing Ligularia fischeri powder (0, 1, 2, 3, 4%) substituted for flour. This study measured the density, pH, spread ratio, volume, color values, hardness, and sensory properties of cookies. The pH of cookie dough significantly decreased in response to addition of Ligularia fischeri powder (LFP) at all levels. The spread factor of cookies also significantly increased with higher LFP content. In addition, Hunter's color L, a, and b values significantly decreased with increasing LFP content. According to hardness measurement, substitution of 1~4% LFP resulted in increased hardness compared to the control. In the sensory evaluation, sensory scores for color, flavor, and overall acceptability were highest in 2% Ligularia fischeri powder cookies. Thus, our results suggest that the optimum amount of Ligularia fischeri powder added to cookies was 2%. These results suggest that Ligularia fischeri powder can be applied to cookies to achieve high quality and functionality.
        4,000원
        485.
        2015.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Porous W with controlled pore structure was fabricated by thermal decomposition and hydrogen reduction process of PMMA beads and WO3 powder compacts. The PMMA sizes of 8 and 50 μm were used as pore forming agent for fabricating the porous W. The WO3 powder compacts with 20 and 70 vol% PMMA were prepared by uniaxial pressing and sintered for 2 h at 1200oC in hydrogen atmosphere. TGA analysis revealed that the PMMA was decomposed at about 400oC and WO3 was reduced to metallic W at 800oC. Large pores in the sintered specimens were formed by thermal decomposition of spherical PMMA, and their size was increased with increase in PMMA size and the amount of PMMA addition. Also the pore shape was changed from spherical to irregular form with increasing PMMA contents due to the agglomeration of PMMA in the powder mixing process.
        4,000원
        486.
        2015.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, effect of core-shell structure on compaction behavior of harmonic powder is investigated. Harmonic powders are made by electroless plating method on Fe powders. Softer Cu shell encloses harder Fe core, and the average size of Fe core and thickness of Cu shell are 34.3 μm and 3.2 μm, respectively. The powder compaction procedure is processed with pressure of 600 MPa in a cylindrical die. Due to the low strength of Cu shell regions, the harmonic powders show better densification behavior compared with pure Fe powders. Finite element method (FEM) is performed to understand the roll of core-shell structure. Based on stress and strain distributions of FEM results, it is concluded that the early stage of powder compaction of harmonic powders mainly occurs at the shell region. FEM results also well predict porosity of compacted materials.
        4,000원
        487.
        2015.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study investigated the microstructure and tensile properties of a recently made block-type Ni-Cr-Al powder porous material. The block-type powder porous material was made by stacking multiple layers of powder porous thin plates with post-processing such as additional compression and sintering. This study used block-type powder porous materials with two different cell sizes: one with an average cell size of 1,200 μm (1200 foam) and the other with an average cell size of 3,000 μm (3000 foam). The γ-Ni and γ’-Ni3Al were identified as the main phases of both materials. However, in the case of the 1,200 foam, a β-NiAl phase was additionally observed. The relative density of each block-type powder porous material, with 1200 foam and 3000 foam, was measured to be 5.78% and 2.93%, respectively. Tensile tests were conducted with strain rates of 10−2~10−4 sec−1. The test result showed that the tensile strength of the 1,200 foam was 6.0~7.1 MPa, and that of 3,000 foam was 3.0~3.3 MPa. The elongation of the 3,000 foam was higher (~9%) than that (~2%) of the 1,200 foam. This study also discussed the deformation behavior of block-type powder porous material through observations of the fracture surface, with the results above.
        4,000원
        488.
        2015.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 리뷰에서는 금속 3D프린팅 산업과 시장에 결정적인 역할을 하는 금속 분말소재와 관련기술의 R&D 전략 수 립을 위한 최근 우리 정부의 노력을 살펴보고 이를 토대 로 우리나라의 분말야금분야 R&D 및 새로운 PM 시장창 출에 관한 발전을 전망해보고자 한다. 따라서 본 리뷰의 내용은 2014년 12월에 미래창조과학부와 산업통상자원부 가 공동으로 수립하여 발간한 3D프린팅 전략기술 로드맵 을 기초하여 작성되었다.
        20,000원
        489.
        2015.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 유채 꽃가루 분말의영양성분 분석과 파쇄한 꽃가루 분말을 이용하여 효모 배양용 액체배지와 고체배지를 제조하여 효모 배양효율을 분석하였다. 유채 꽃가루 분말(100 g)은 탄수화물 58.9 g, 단백질 20.8 g, 지방 4.1 g, 회분 2.5 g 및 수분 13.7 g으로 구성되었다. 당질 중에서는 Fructose(13.7 g), Glucose(11.1 g)와 Sucrose(6.6 g), 미네랄 중에서는 K(606.7 mg)와 P(603.3 mg) 함 향이 높았다. 유리 아미노산은 Glutamic acid(2,482.4 mg), Aspartic acid(2,136.5 mg), Lysine(1,648.3 mg), 및 Leucine(1,631.1 mg) 순으로 많았다. 유채 꽃가루분말을 단독 또는 NaCl을 첨가하여 액체배지 및 고체배지 제조하고 효모를 배양한 결 과, 꽃가루 분말이 15 g/L 이상 함유된 액체배지는 효모 배양 후 건물중이 YPD 배지(대조구)에 비해 많았고, 꽃가루 분말의 농도 의존적으로 효모 건물중이 증가하였다. 또한 액체배지에 NaCl을 1~20 g/L 추가 시 배양된 효모의 건물중이 한층 더 증가하였다. 유채 꽃가루로 제조한 고체배지를 이용하여 효모 를 배양(48시간)한 결과, 콜로니(colonies) YPD 배지와 유사하게 잘 자랐다.
        4,000원
        490.
        2015.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 시멘트 노출에 따른 어류 조직의 형태 생리적 변화를 분석하여 용해된 시멘트 분말이 어류에 미치는 영향을 조사하고자 하였다. 용해된 시멘트 분말에 노출된 아가미는 일차새변의 두께가 두꺼워지고, 염세포와 점액세포도 두드러지게 활성이 증가되고 있으며, 이차새변의 새엽에서는 상피세포의 증식과 박리 및 곤봉화 현상도 관찰되었다. 신장 조직에서는 보우만 주머니 공간이 넓게 관찰되었고, 표피 조직은 표피층의 두께가 감소하며 진피층의 배열이 불규칙해지는 것으로 관찰되었다. 항산화효소와 LDH의 활성은 조직 및 노출 기간에 따라 활성에 차이가 있는 것으로 나타났다. 표피 조직에서 용해된 시멘트 분말에 의해 발현이 증가되는 단백질은 해당과정과 에너지 대사과정에 관여하는 단백질로 확인되었고 발현이 저하된 단백질들은 근수축에 관여하는 근섬유 구성 단백질로 조사되었다. 이러한 결과로 보아 용해된 시멘트 분말은 붕어 조직의 형태적 변형과 생리적 기능의 약화를 초래하여 어류의 생존에 커다란 위협이 될 요인으로 작용할 수 있을 것으로 사료된다.
        4,300원
        491.
        2015.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        As well-known wrought stainless steel, sintered stainless steel (STS) has excellent high-temperature anticorrosion even at high temperature of 800ºC, and exhibits good corrosion resistance in air. However, when temperature increases above 900ºC, the corrosion resistance of STS begins to deteriorate and dramatically decreases. In this study, the effects of phase and composition of STS on high-temperature corrosion resistances are investigated for STS 316L, STS 304 and STS 434L above 800ºC. The morphology of the oxide layers are observed. The oxides phase and composition are identified using X-ray diffractometer and energy dispersive spectroscopy. The results demonstrate that the best corrosion resistance of STS could be improved to that of 434L. The poor corrosion resistance of the austenitic stainless steels is due to the fact that NiFe2O4 oxides forming poor adhesion between the matrix and oxide film increase the oxidation susceptibility of the material at high temperature.
        4,000원
        492.
        2015.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        A precipitation behavior of nano-oxide particle in Fe-5Y2O3 alloy powders is studied. The mechanically alloyed Fe-5Y2O3 powders are pressed at 750oC for 1h, 850oC for 1h and 1150oC for 1h, respectively. The results of Xray diffraction pattern analysis indicate that the Y2O3 diffraction peak disappear after mechanically alloying process, but Y2O3 and YFe2O4 complex oxide precipitates peak are observed in the powders pressed at 1150oC. The differential scanning calorimetry study results reveal that the formation of precipitates occur at around 1054oC. Based on the transmission electron microscopy analysis result, the oxide particles with a composition of Y-Fe-O are found in the Fe-5Y2O3 alloy powders pressed at 1150oC. It is thus conclude that the mechanically alloyed Fe-5Y2O3 powders have no precipitates and the oxide particles in the powders are formed by a high temperature heat-treatment
        4,000원
        493.
        2015.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, cobalt nanopowder is fabricated by sonochemical polyol synthesis and magnetic separation method. First, sonochemical polyol synthesis is carried out at 220oC for up to 120 minutes in diethylene glycol (C4H10O3). As a result, when sonochemical polyol synthesis is performed for 50 minutes, most of the cobalt precursor (Co(OH)2) is reduced to spherical cobalt nanopowder of approximately 100 nm. In particular, aggregation and growth of cobalt particles are effectively suppressed as compared to common polyol synthesis. Furthermore, in order to obtain finer cobalt nanopowder, magnetic separation method using magnetic property of cobalt is introduced at an early reduction stage of sonochemical polyol synthesis when cobalt and cobalt precursor coexist. Finally, spherical cobalt nanopowder having an average particle size of 22 nm is successfully separated.
        4,000원
        494.
        2015.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In recent years, industrial demands for superior mechanical properties of powder metallurgy steel components with low cost are rapidly growing. Sinter hardening that combines sintering and heat treatment in continuous one step is cost-effective. The cooling rate during the sinter hardening process dominates material microstructures, which finally determine the mechanical properties of the parts. This research establishes a numerical model of the relation between various cooling rates and microstructures in a sinter hardenable material. The evolution of a martensitic phase in the treated microstructure during end quench tests using various cooling media of water, oil, and air is predicted from the cooling rate, which is influenced by cooling conditions, using the finite element method simulations. The effects of the cooling condition on the microstructure of the sinter hardening material are found. The obtained limiting size of the sinter hardening part is helpful to design complicate shaped components.
        4,000원
        495.
        2015.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, the behavior of densification of copper powders during high-pressure torsion (HPT) at room temperature is investigated using the finite element method. The simulation results show that the center of the workpiece is the first to reach the true density of copper during the compressive stage because the pressure is higher at the center than the periphery. Subsequently, whole workpiece reaches true density after compression due to the high pressure. In addition, the effective strain is increased along the radius during torsional stage. After one rotation, the periphery shows that the effective strain is increased up to 25, which is extensive deformation. These high pressure and severe strain do not only play a key role in consolidation of copper powders but also make the matrix harder by grain refinement.
        3,000원
        496.
        2015.02 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        NiAl2O4 nanoparticle was synthesized by a reverse micelle processing for inorganic pigment. N (NO3)2·6H2O and Al(NO3)3·9H2O were used for the precursor in order to synthesize NiAl2O4 nanoparticles. The aqueous solution, which consisted of a mixing molar ratio of Ni/Al, was 1:2 and heat treated at 800~1100 oC for 2h. The average size and distribution of synthesized NiAl2O4 powders are in the range of 10-20 nm and narrow, respectively. The average size of the synthesized NiAl2O4 powders increased with an increasing water-to-surfactant molar ratio and heating temperature. The crystallinity of synthesized NiAl2O4 powder increased with an increasing heating temperature. The synthesized NiAl2O4 powders were characterized by X-ray diffraction analysis(XRD), a field emission scanning electron microscop (FE-SEM), and a color spectrophotometer. The properties of synthesized powders were affected as a function such as a molar ratio and heating temperature. Results indicate that synthesis using a reverse miclle processing is a favorable process to obtain NiAl2O4 spinels at low temperatures. The procedure performed suggests that this new synthesis route for producing these oxides has the advantage of being fast and simple. Colorimetric coordinates indicate that the pigments obtained exhibit blue colors.
        4,000원
        497.
        2014.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study aimed to investigate the changes in antioxidant activities, quality characteristics, and storage stability of mayonnaise prepared with perilla oil with the addition of mulberry powder ranging from 0 to 5%. The antioxidant activities of perilla oil mayonnaise (PM), as determined by DPPH and ABTS radical scavenging activity, as well as FRAP and total phenolics content were improved by the addition of mulberry powder compared with the control sample. Antioxidant activities were dependent on the amount of mulberry powder added. Lipid oxidation of PM decreased with a higher amount of mulberry powder, based on measurements of peroxide value. The emulsion stability of PM increased with decreases in the amount of mulberry powder level. The a-value in PM color increased with increasing amount of mulberry powder. Sensory evaluation showed that the highest score in overall acceptability of PM was achieved with 4% mulberry.
        4,000원
        498.
        2014.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        A study was undertaken to examine the effect of adding freeze dried maquiberry powder on the quality of pound cakes. Freeze dried maquiberry was added to the flour at a ratio of 0.5, 1, 1.5 and 2.5%. The antioxidant activity was estimated by DPPH free radical scavenging activity, the total phenolic compounds content, and flavonoid content in freeze dried maquiberry powder of pounds cakes. Antioxidative activity was highly correlated with the total phenolic and total flavonoids contents of freeze dried maquiberry powder of pound cakes (r=0.9126, p<0.001, r=0.8366, p<0.001, respectively). The quality characteristics of freeze dried maquiberry powder of poundcakes were estimated. The specific volume decreased significantly with increased substitution level of freeze dried maquiberry powder (p<0.01). The lightness significantly decreased with increased freeze-dried maquiberry powder of pound cake crust and crumb (p<0.01, p<0.01). The hardness and adhesiveness increased, while gumminess tended to reduce with increased maquiberry powder. The consumer acceptability score of 0.5~2.5% freeze dried maquiberry powder of pound cakes ranked significantly (p<0.01) higher than those of the other groups in overall preference. These results showed that freeze dried maquiberry powder is a good ingredient to increase consumer acceptability and health.
        4,200원
        499.
        2014.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구에서는 전통 식품 소재로의 활용성을 높이기 위해 참죽나무 순을 동결건조하여 일반성분과 무기질 함량을 측정하였고, 추출용매를 달리하여 얻은 열수 추출물과 70% 에탄올 추출물로부터 총 폴리페놀 및 플라보노이드 함량과 항산화능을 살펴보았다. 참죽나무 순의 일반성분 및 무기질 분석 결과, 조단백질, 조섬유, 칼슘과 칼륨 함량이 높게 측정되었다. 총 폴리페놀과 플라보노이드는 참죽나무 순 분말 열수 추출물보다 70% 에탄올 추출물에서 함량이 더 높았으며, DPPH 유리 라디칼 소거능과 FRAP 또한 70% 에탄올 추출물에서 더 높은 항산화력을 나타냈다. 이상의 결과로 볼 때 참죽나무 순 분말은 영양성과 식이섬유소의 기능성이 높아 식품의 재료로 이용가능성이 높으며, 참죽나무 순 분말로부터 유용성분 용출 및 기능성 증대를 위해서는 70% 에탄올로 추출하는 것이 바람직하다고 생각된다.
        4,000원
        500.
        2014.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Eu2+/Dy3+-doped Sr2MgSi2O7 powders were synthesized using a solid-state reaction method with flux (NH4Cl). Thebroad photoluminescence (PL) excitation spectra of Sr2MgSi2O7:Eu2+ were assigned to the 4f7-4f65d transition of the Eu2+ ions,showing strong intensities in the range of 375 to 425nm. A single emission band was observed at 470nm, which was the resultof two overlapping subbands at 468 and 507nm owing to Eu(I) and Eu(II) sites. The strongest emission intensity ofSr2MgSi2O7:Eu2+ was obtained at the Eu concentration of 3mol%. This concentration quenching mechanism was attributableto dipole-dipole interaction. The Ba2+ substitution for Sr2+ caused a blue-shift of the emission band; this behavior was discussedby considering the differences in ionic size and covalence between Ba2+ and Sr2+. The effects of the Eu/Dy ratios on thephosphorescence of Sr2MgSi2O7:Eu2+/Dy3+ were investigated by measuring the decay time; the longest afterglow was obtainedfor 0.01Eu2+/0.03Dy3+.
        4,000원