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        검색결과 20

        3.
        2017.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The objective of this experiment was to determine the effect of supplementation of hot melt extrusion (HME) processed Zn sulfate on growth performance, nutrients digestibility, small intestinal morphology and excretion of Zn in weanling pigs. A total of 200 piglets of mixed sex randomly allotted to four treatments on the basis of initial BW (7.15±0.81 kg). There were five replicates in each treatment with 10 pigs per replicate. The experimental treatments consisted of: 1) basal diet containing ZnSO4; 2) basal diet containing Zn-Methionine (ZnMet); 3) basal diet containing low level of nano-Zn as HME (ZnHME50); 4) basal diet containing medium level of nano-Zn as HME ZnSO4 (Zn-HME75). The average daily gain was improved by the ZnMet and ZnHME75 compared with the pigs fed ZnSO4 supplemented diets (p=0.009). Moreover, ZnHME75 and ZnMet affected on the ATTD of CP during phase 2 (p=0.014). The villus height (VH) was affected by increasing when pigs fed diets supplemented the ZnHME75 (P=0.044). The pigs fed diets supplemented ZnHME50 had significantly the lowest (p=0.037) Zn content in liver compared with other treatments. The Zn content in the feces was significantly higher (p<0.001) in ZnSO4 and ZnMet compared with ZnHME50 or ZnHME75. In conclusion, it could be concluded that dietary Zn can be reduced by 25% with ZnHME without any detrimental effect on performance of weanling pigs.
        4,200원
        4.
        2006.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The microstructural and mechanical properties of Al-Si alloyed powder, prepared by gas atomization fallowed by hot extrusion, were studied by optical and scanning electron microscopies, hardness and wear testing. The gas atomized Al-Si alloy powder exhibited uniformly dispersed Si particles with particle size ranging from 5 to . The hot extruded Al-Si alloy shows the average Si particle size of less than . After heat-treatment, the average particle size was increased from 2 to . Also, mechanical properties of extruded Al-Si alloy powder were analyzed before and after heat-treatment. As expected from the microstructural analysis, the heat-treated samples resulted in a decrease in the hardness and wear resistance due to Si particle growth. The friction coefficient of heat-treated Al-Si alloyed powder showed higher value tough all sliding speed. This behavior would be due to abrasive wear mechanism. As sliding speed increases, friction coefficient and depth and width of wear track increase. No significant changes occurred in the wear track shape with increased sliding speed.
        4,000원
        5.
        2006.09 구독 인증기관·개인회원 무료
        Chemically pure, hydride/dehydride titanium powders were cold pre-compacted then extruded at and under argon. The extrusions were 100% dense with a narrow band of surface porosity and equiaxed microstructure of similar magnitude to the starting material. The tensile properties of the bars were better than conventionally extruded CP titanium bar product. Outcomes from this study have assisted in the identification of a number of key characteristics important to the extrusion of titanium from pre-compacted CP titanium powders, allowing the elimination of canning and hot isostatic pressing (HIPping) of billets prior to extrusion as per conventional PM processes.
        7.
        2006.09 구독 인증기관·개인회원 무료
        Two different commercial aluminium powder grades have been densified by direct hot extrusion. The extrusion temperature was 425 °C, with an extrusion ratio of 1:16. Prior to extrusion, some green compacts were pre-sintered (500 °C). The evolution of the extrusion load during the process and the hardness of the final products have been investigated. Additionally, microstructural characterization by X-ray diffraction (XRD), Scanning Electron Microscopy (SEM) and Electron Backscattered Diffraction (EBSD) was carried out. The obtained results evidence grain refinement. Additionally, inter-metallic precipitation, dynamic recovery and geometric dynamic recrystallization take place depending on some process variables, powder composition, heat treatment, strain ...
        11.
        1995.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        분말야금법으로 제조된 A6061기 입자분산강화 복합재의 열간압술가공에 있어서 압출특성에 미치는 강화입자의 종류, 빌렛특성 및 암술조건의 영향에 대하여 조사하였다. A6061기 복합재료의 열간 압술 전단 변형저항에 미치는 강화입자종류의 영향은 Si Cw > A12 O3f > A12 O3f > Si Cp의 순으로 되었으며, 모든 강화입자에서 부피분율이 증가함에 따라서 Kw값도 증가하였다. 압출조건, 강화입자의 첨가량 및 첨가입자의 평균입도에 관계없이 A12 O3p가 첨가된 복합재의 열간압출가공에 필요한 소요압력은 Si Cp의 경우보다 컸다. 압출압력은 압출 다이스 반각이 커질수록 감소하는 경향은 나타났다. 이것은 다이스 반각에 의해 생성되는 빌렛과의 접촉면적이 증가하여 전단마찰응력(m k3)이 상승하기 때문이다. 압출시 압출온도 상승은 저온에서 ~50˚C 정도 증가하였으며, 압출온도가 500˚C 이상이 되면 압출재 표면에 극심한 tearing이 발생하였다. 강화입자의 첨가량이 증가할수록 이 현상은 더 심하게 되었다.게 되었다.
        4,000원
        12.
        1994.10 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        현재까지 잘 알려진 압출이론식이 생산현장에 응용될 수 있는가를 조사하기 위하여, Al-Si합금을 대상소재로 하여 각 압출이론식에 나타난 유도응력 Kf, 변형저항 Kw , Dead Metal Zone(DMZ)의 경각(α)등을 측정하였으며, 이들 값을 이용하여 최대압출력을 계산하였다. 550ton의 압출기를 이용하여 측정한 최대 압출력과의 비교분석을 행하였으며, 그 결과 이론식에 의해 최대압출력을 계산하기 위해 측정된 유동응력 및 변형저항 값은 신뢰할 수 있을 것으로 사료되었는데, 이것은 0.5이하에서 결정된 변형효율 η f로서 판단 할 수 있었다. 최대 압출력은 Si함량이 증가할 수록 증가하게 되나, 압출온도가 증가할 수록 감소하고 있음을 알 수 있었다. Siebel식으로부터 계산된 최대압출력은 본 실험을 통하여 얻어진 최대압출력에 비교적 근접하고 있으나. Geleji식으로부터 계산된 최대압출력은 DMZ의경각 α가 50˚일 경우 , 본 실험에 의해 얻어진 실제의 최대압출력에 급접하고 있었다. Geleji의 식은 DMZ의 경각에 매우 민감하고, 대상재료마다. DMZ를 일일이 측정해야 하는 번거로움 때문에 생산현장에서는 Siebel의 식을 이용하는 것이 보다 편리할 것으로 사료된다.
        4,000원
        14.
        2018.10 KCI 등재 서비스 종료(열람 제한)
        Background: The objective of this study was to make colloidal dispersions of the active compounds of radix of Angelica gigas Nakai that could be charaterized as nano-composites using hot melt extrusion (HME). Food grade hydrophilic polymer matrices were used to disperse these compound in aqueous media. Methods and Results: Extrudate solid formulations (ESFs) mediated by various HPMCs (hydroxypropyl methylcelluloses) and Na-Alg polymers made from ultrafine powder of the radix of Angelica gigas Nakai were developed through a physical crosslink method (HME) using an ionization agent (treatment with acetic acid) and different food grade polymers [HPMCs, such as HP55, CN40H, AN6 and sodium alignate (Na-Alg)]. X-ray powder diffraction (XRD) analysis confirmed the amorphization of crystal compounds in the HP55-mediated extrudate solid formulation (HP55-ESF). Differential scanning calorimetry (DSC) analysis indicated a lower enthalpy (ΔH = 10.62 J/g) of glass transition temperature (Tg) in the HP55-ESF than in the other formulations. Infrared fourier transform spectroscopy (FT-IR) revealed that new functional groups were produced in the HP55-ESF. The content of phenolic compounds, flavonoid (including decursin and decursinol angelate) content, and antioxidant activity increased by 5, 10, and 2 times in the HP55-ESF, respectively. The production of water soluble (61.5%) nano-sized (323 ㎚) particles was achieved in the HP55-ESF. Conclusions: Nano-composites were developed herein utilizing melt-extruded solid dispersion technology, including food grade polymer enhanced nano dispersion (< 500 ㎚) of active compounds from the radix of Angelica gigas Nakai with enhanced solubility and bioavailability. These nano-composites of the radix of Angelica gigas Nakai can be developed and marketed as products with high therapeutic performance.
        15.
        2018.10 서비스 종료(열람 제한)
        Background : The objective of this study was to make colloidal dispersion of the active compound was characterized nano-composite from radix of Angelica gigas Nakai using hot melt extrusion (HME). Therefore, food grade hydrophilic polymer matrices was used to disperse compound in aqueous media. Methods and Results : Extrudate solid formulations (ESFs) mediated various HPMCs (hydroxypropyl methylcellulose) and Na-Alg polymer from ultrafine powder of radix of Angelica gigas Nakai was developed through physical crosslink method (HME) with ionization agent (treatment of acetic acid) and food grade polymer [HPMCs such as HP55, CN40H, AN6 and sodium alignate (Na-Alg)]. X-ray powder diffraction (XRD) analysis confirmed the amorphization of crystal compounds in extrudate solid formulations mediated HP55 (HP55-ESF). Differential scanning calorimetry (DSC) analysis indicated a lower enthalpy (ΔH = 10.62 J/g) of glass transition temperature (Tg) in HP55-ESF. Infrared fourier transform spectroscopy (FT-IR) reveled new functional groups produced in HP55-ESF. Phenolic compound, flavonoid (including decursin and decursinol angelate) and antioxidant activity increased at 5, 10 and 2 times in HP55-ESF. Water solubility (61.5%) nano size (323 ㎚) particle was achieved in the HP55-ESF. Conclusion : Nano-composites have been developed utilizing melt-extruded solid dispersions technology by food grade polymer enhanced nano dispersion (< 500 ㎚) of active compound from radix of Angelica gigas Nakai with enhanced solubility and bioavailability. This nano-composites of radix of Angelica gigas Nakai developmental and marketed products to enable therapeutic performance.
        16.
        2018.10 서비스 종료(열람 제한)
        Background : The root of Angelica gigas Nakai is used as a traditional herbal medicine in Korea for the treatment of many diseases. Poor water solubility of the active compounds from A. gigas Nakai is a major obstacle to bioavailability. Methods and Results : This work aimed to enhance the solubility of active compounds by a chemical (viz. surfactant) and physical (HME, hot melt extrusion) crosslinking method (CPC) in A. gigas Nakai. Infrared fourier transform spectroscopy (FT-IR) revealed multiple peaks in extrudate solids representing new functional groups including carboxylic acid, alkynes and benzene derivatives. Differential scanning calorimetry (DSC) analysis of the extrudate showed lower glass transition temperature (Tg) and lower enthalpy (ΔH) [Tg: 43℃; ΔH: <6 (J/g)] compared to the non-extrudate (Tg 68.5℃; ΔH: 123.2) formulations. X-ray powder diffraction (XRD) analysis revealed amorphization of crystal materials in extrudate solid. In addition, enhanced solubility (53%), nanonization (403 ㎚), and higher amount of extracted phenolic compounds were achieved in the extrudate solid compared to non extrudate (36%, 1499 ㎚, respectively). Among the different extrudates, acetic acid and span 80 mediated formulations showed superior extractions efficiency. Conclusion : We conclude that the HME successfully enhanced the production of amorphous nano dispersions of phenolic compound including decursin from extrudate solid formulations. human dermal fibroblasts, which is, associated with the regulation of procollagen biosynthesis resulting from AMRP-induced TGF-β1 expression and the mitogenic activity in HDF cells, and therefore, is expected to reduce the age-dependent loss of extracellular matrix proteins.
        17.
        2018.08 KCI 등재 서비스 종료(열람 제한)
        Background: The root of Angelica gigas Nakai is used as a traditional herbal medicine in Korea for the treatment of many diseases. However, the poor water solubility of the active components in A. gigas Nakai is a major obstacle to its bioavailability. Methods and Results: This work aimed at enhancing the solubility of the active compounds of A. gigas Nakai by a chemical (using a surfactant) and physical (hot melt extrusion, HME) crosslinking method. Fourier transform infrared spectroscopy revealed multiple peaks in the case of the extrudate solids, attributable to new functional groups including carboxylic acid, alkynes, and benzene derivatives. Differential scanning calorimetry analysis showed that the extrudate soilid had a lower glass transition temperature (Tg) and enthalpy (ΔH) (Tg : 43℃, ΔH : < 6 J/g) as compared to the non-extrudate (Tg : 68.5℃, ΔH : 123.2) formulations. X-ray powder diffraction analysis revealed the amorphization of crystalline materials in the extrudate solid. In addition, enhanced solubility (53%), nanonization (403 ㎚), and a higher amount of extracted phenolic compounds were achieved in the extrudate solid than in the non-extrudate (solubility : 36%, nanonization : 1,499 ㎚) formulation. Among the different extrudates, acetic acid and span 80 mediated formulations showed superior extractions efficiency. Conclusions: HME successfully enhanced the production of amorphous nano dispersions of phenolic compound including decursin from extrudate solid formulations.
        18.
        2017.05 서비스 종료(열람 제한)
        Background : Cu ion is an essential mineral of animal feed. But rapid degradation of Cu ion in animal intestine causes poor immune activity and potential environment hazard. Therefore, to enhance immune system and control metal ion deliverly in intestine, we developed Cu ion nano suspension. In animal feed, > 127 ㎎/g of Cu ion are found but only 5 - 7 ㎎ are used out of them. Therefore, huge loss of Cu ion causes environment, economy and animal health problem. Methods and Results : Seven formulation were prepared to prepare nano suspension (particle size < 200 ㎚) of CuSO4. The particle diameter, polydispersity index, and zeta potential values of the samples were measured using dynamic light scattering (DLS) and laser Doppler methods (ELS-Z1000; Otsuka Electronics, Tokyo, Japan). Absorbance and Cu ion concentration was measured using UV-VIS Spectrophotometer. Cu ion nano particle (< 200 ㎚) was found in a formulation comprised of Cu ion : surfactant (lipophilic : hydrophilic) and PEG. In consistence with this result, total absorbance and concentration was found higher in the same formulation compared to control. Conclusion : From our experiment we may conclude that mixture of Cu ion : surfactant (lipophilic : hydrophilic) and PEG successfully prepared nano suspension which slow down the degradation of Cu ion in intestine with improving feed quality, animal health and prevent potential environment pollution.
        19.
        2016.10 서비스 종료(열람 제한)
        Background : Angelica gigas is a biennial or short lived perennial plant found in China, Japan, and Korea. The root of Angelica gigas has been used in oriental traditional medicine and is marketed as a functional food product in Europe and North America. Cham-Dang-Gui (Korean Angelica, the dried root of Angelica gigas Nakai (AGN)) has been principally cultivated in Korea and used as a Korean medicinal herb. It contains several chemicals, such as pyranocoumarins, essential oils, and polyacetylenes. Methods and Results : Fresh Angelica gigas Nakai was purchased from Pyeongchang (Korea). Standard samples of D, DA were obtained from Korea Promotion Institute for Traditional Medicine Industry (Gyeongsan, Korea). Soluplus was purchased from BASF (Ludwigshafen, Germany). AGN was dried in the oven at 55°C for 24 h and cooled at room temperature. The AGN sample was then stored at 4°C until milling. Oral solid formulations based on Angelica gigas Nakai and Soluplus were prepared by the hot melt extrusion (HME) method. AGN was pulverized into coarse and ultrafine particles, and their particle size and morphology were investigated. Ultrafine AGN particles were used in the HME process with high shear to produce AGN-based formulations. In simulated gastrointestinal fluids (pH 1.2 and pH 6.8) and water, significantly higher amounts of the major active components of AGN, decursin (D) and decursinol angelate (DA), were extracted from the HME-processed AGN/Soluplus group than the AGN EtOH extract group (p < 0.05). Based on an in vivo pharmacokinetic study in rats, the relative oral bioavailability of decursinol (DOH), a hepatic metabolite of D and DA, in administered mice was 8.75-fold higher than in AGN EtOH ext-treated group. Conclusion : Soluplus-included solid formulation prepared by HME can be a promising carrier for oral delivery of phytochemicals. These findings suggest that HME-processed AGN/Soluplus formulation could be a promising therapeutic candidate for oral bioavailability.