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        검색결과 1,826

        601.
        2013.02 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        In this study, using a tin chloride solution as the raw material, a nano-sized tin oxide powder with an average particle size below 50 nm is generated by a spray pyrolysis process. The properties of the tin oxide powder according to the nozzle tip size are examined. Along with an increase in the nozzle tip size from 1 mm to 5 mm, the generated particles that appear in the shape of droplets maintain an average particle size of 30 nm. When the nozzle tip size increases from 1 mm to 2 mm, the average size of the generated particles is around 80-100 nm, and the ratio of the independent particles with a compact surface structure increases significantly. When the nozzle tip size is at 3 mm, the majority of the generated particles maintain the droplet shape, the average size of the droplet-shaped particles increases remarkably compared to the cases of other nozzle tip sizes, and the particle size distribution also becomes extremely irregular. When the nozzle tip size is at 5 mm, the ratio of droplet-shaped particles decreases significantly and most of the generated particles are independent ones with incompact surface structures. Along with an increase in the nozzle tip size from 1 mm to 3 mm, the XRD peak intensity increases, whereas the specific surface area decreases greatly. When the nozzle tip size increases up to 5 mm, the XRD peak intensity decreases significantly, while the specific surface area increases remarkably.
        4,000원
        602.
        2013.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        A study of oxidation kinetic of Fe-36Ni alloy has been investigated using thermogravimetric apparatus (TGA) in an attempt to define the basic mechanism over a range of temperature of 400 to and finally to fabricate its powder. The oxidation rate was increased with increasing temperature and oxidation behavior of the alloy followed a parabolic rate law at elevated temperature. Temperature dependence of the reaction rate was determined with Arrhenius-type equation and activation energy was calculated to be 106.49 kJ/mol. Based on the kinetic data and micro-structure examination, oxidation mechanism was revealed that iron ions and electrons might migrate outward along grain boundaries and oxygen anion diffused inward through a spinel structure, .
        4,000원
        603.
        2013.02 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        In this study, GaN powders were synthesized from gallium oxide-hydroxide (GaOOH) through an ammonification process in an NH3 flow with the variation of B2O3 additives within a temperature range of 300-1050˚C. The additive effect of B2O3 on the hexagonal phase GaN powder synthesis route was examined by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and Fourier transformation infrared transmission (FTIR) spectroscopy. With increasing the mol% of B2O3 additive in the GaOOH precursor powder, the transition temperature and the activation energy for GaN powder formation increased while the GaN synthesis limit-time (tc) shortened. The XPS results showed that Boron compounds of B2O3 and BN coexisted in the synthesized GaN powders. From the FTIR spectra, we were able to confirm that the GaN powder consisted of an amorphous or cubic phase B2O3 due to bond formation between B and O and the amorphous phase BN due to B-N bonds. The GaN powder synthesized from GaOOH and B2O3 mixed powder by an ammonification route through β-Ga2O3 intermediate state. During the ammonification process, boron compounds of B2O3 and BN coated β-Ga2O3 and GaN particles limited further nitridation processes.
        4,000원
        604.
        2013.02 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        The study of grinding behavior characteristics on aluminum powders and carbon nano tubes (CNTs) has recently gained scientific interest due to their useful effect in enhancing advanced nano materials and components, which significantly improves the property of new mechatronics integrated materials and components. We performed a series of dry grinding experiments using a planetary ball mill to systematically investigate the grinding behavior during Al/CNTs nano composite fabrication. This study focused on a comparative study of the various experimental conditions at several variations of rotation speeds, grinding time and with and without CNTs. The results were monitored for the particle size distribution, median diameter, crystal structure from XRD pattern and particle morphology at a given grinding time. It was observed that pure aluminum powders agglomerated with low rotation speed and completely enhanced powder agglomeration. However, Al/CNTs composites were achieved at maximum experiment conditions (350 rpm, 60 min.) of this study by a mechanical alloy process for Al/CNTs mixed powders because the grinding behavior of Al/CNTs composite powder was affected by addition of CNTs. Indeed, the powder morphology and crystal size of the composite powders changed more by an increase of grinding time and rotation speed.
        4,000원
        605.
        2013.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구에서는 초임계 CO2 추출법을 이용하여 공정변수가 대두유의 수율에 미치는 영향과 초고압 처리가 초임계 추출에 미치는 영향에 대하여 분석하였다. RSM 실험법을 통한 최적화 실험에서 468.18 bar, 80.23oC, 46.82 g/min의 조건에서 최대값 25.88%를 나타내었다. 초임계 추출법의 최적추출조건에서 초고압 전처리 후 추출 수율은 17.15-23.66%로 전처리 전보다 감소하는 경향을 나타내었다. 462.13MPa, 1분의 추출조건에서 정상점은 최대값으로 24.91%가 예측되었다. 초고압 전처리 후 초임계 추출에서 수율이 증가하지 않은 이유는 초고압 전처리시 입자의 뭉침현상이 일어나 평균입자크기가 증가하여 나타난 현상으로 추론하였다. 결과적으로 초고압 전처리는 초임계 추출 수율 증가에 영향을 미치지 못하는 것을 알 수 있었다. 초임계 CO2 추출법을 이용하여 대두유를 추출할 경우 추출 압력, 유량이 높을수록 추출온도가 낮을수록 더 많은 양의 대두유를 추출할 수 있다.
        4,000원
        607.
        2013.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Fe-TiC composite powder was fabricated via two steps. The first step was a high-energy milling of FeO and carbon powders followed by heat treatment for reduction to obtain a (Fe+C) powder mixture. The optimal condition for high-energy milling was 500 rpm for 1h, which had been determined by a series of preliminary experiment. Reduction heat-treatment was carried out at for 1h in flowing argon gas atmosphere. Reduced powder mixture was investigated by X-ray Diffraction (XRD), Field Emission-Scanning Electron Microscopy (FE-SEM) and Laser Particle Size Analyser (LPSA). The second step was a high-energy milling of (Fe+C) powder mixture and additional powder, and subsequent in-situ synthesis of TiC particulate in Fe matrix through a reaction of carbon and Ti. High-energy milling was carried out at 500 rpm for 1 h. Heat treatment for reaction synthesis was carried out at for 1 h in flowing argon gas atmosphere. X-ray diffraction (XRD) results of the fabricated Fe-TiC composite powder showed that only TiC and Fe phases exist. Results from FE-SEM observation and Energy-Dispersive X-ray Spectros-copy (EDS) revealed that TiC phase exists uniformly dispersed in the Fe matrix in a form of particulate with a size of submicron.
        4,000원
        608.
        2013.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        후춧가루의 비가열 살균기술을 개발하고자 감압방전플라즈마(LPDP)를 이용한 살균을 시도하였고 LPDP 처리에 의한 품질변화를 조사하였다. 시판 후춧가루의 미생물 오염도는 가공제품에서는 세균, 진균 모두 103 CFU/g 수준이었던 반면, 재래시장에서 벌크로 판매하는 제품에서는 세균은 106 CFU/g, 진균은 107 CFU/g 수준의 오염도를 보였다. 후춧가루의 LPDP 살균패턴은 1차 반응으로 나타났으며, 세균과 진균의 살균속도상수는 각각 0.0841min-1 과 0.0696min-1 로서 세균이 진균에 비해 LPDP에 약간 더 민감하였다. LPDP 처리는 후춧가루의 색에는 영향을 미치지 않았으나 piperine 함량을 낮추는 것으로 확인되었다. Piperine 감소에도 불구하고 후춧가루의 관능특성은 LPDP 처리에 의해 영향을 받지 않았다.
        4,000원
        609.
        2013.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The extraction of metallic pure vanadium powder from raw oxide has been tried by Mg-reduction. In first stage, powders as initial raw material was reduced by hydrogen gas into phase. powder was reduced in next stage by magnesium gas at 1,073K for 24 hours. After reduction reaction, the MgO component mixed with reduced vanadium powder were dissolved and removed fully in 10% HCl solution for 5 hours at room temperature. The oxygen content and particle size of finally produced vanadium powders were 0.84 wt% and 1 , respectively
        4,000원
        610.
        2013.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In the present study, we systematically investigated the effect of Mn addition on nitrogenation behavior and magnetic properties of Sm-Fe powders produced by reduction-diffusion process. Alloy powders with only single phase were successfully produced by the reduction-diffusion process. The coercivity of powder rapidly increased during nitrogenation and reached the maximum of 637 Oe after 16 hours. After further nitrogenation, it decreased. In contrast, the coercivity of powder gradually increased during nitrogenation for 24 hours. The coercivity of powder was higher than that of powder at the same condition of nitrogenation. It was considered that the Mn addition facilitates the nitrogenation of powder and enhances the coercivity.
        4,000원
        611.
        2013.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The effect of particle size distribution on green and sintered properties of Fe-Cr-Mo prealloy powder was investigated in this study. For the study, prealloyed Fe-Cr-Mo powders with different particle sizes were mixed as various ratios and cold compacted at various pressure and sintered at for 30 min, atmosphere in the continuous sintering furnace. The results shows that the powders with large particle size distribution have high compressibility and low ejection force. However the green strength are much less than those with small particle size distribution. Tensile prperties of the sintered specimes with large particles size also have high strength and elongation.
        4,000원
        612.
        2012.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study investigated reduction of microbial population, water soluble pigment, capsanthin content, surface color (Hunter L, a, b, ΔE), and sensory properties of pepper powder by LED (red, yellow, blue, green) treatments. LED (red, yellow, blue, green) treatment were conducted in 1,000 lux storage at 25oC for 10 days. The total aerobic bacteria was no significant difference among the control and treated with LED during 10 days. In yellow LED treatment, yeast and molds were decreased about 1.76 log. Surface color such as lightness (L), redness (a), yellowness (b) were showed a decreasing tendency as the storage period. In the overall color difference (ΔE) of yellow LED treatment was lower less than 3.0. Water soluble pigment was no difference in control and LED treated samples during storage period. Capsanthin content was significantly decreased as storage period was increased, but no significant differences were observed among red and yellow LED treatments. Sensory properties of control was significantly reduced by storage period but yellow and green LED treatments were no significantly differences.
        4,000원
        613.
        2012.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was conducted to monitor and evaluate microbial contamination during manufacturing process in 6 red pepper powder factories. Red pepper powder samples were taken from manufacturing facilitates, working area and workers’ hands to determine sanitary indicator bacteria (SIB) such as aerobic bacteria and coliform group as well as pathogenic indicator bacteria (PIB) such as Staphylococcus aureus, E.coli, Salmonella spp., Listeria monocytogenes, and Bacillus cereus. The results indicated that SIB in primary materials was detected as low as 3 log units and E.coil and Staphylococcus aureus of PIB were detected. After grinding process, aerobic bacteria, fungi, and coliform group increased 52% and 108%, respectively. In final products, PIB was not detected except for one found Staphylococcus aureus by which workers’ hands were contaminated. Moreover, UV detectors in all the manufacturers were not able to reduce bacteria. Thus, this data suggest that a stringent safety management be needed to prevent cross contamination, and also reconsider effectiveness of facility.
        4,000원
        614.
        2012.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Sulgidduk is a kind of basic steamed rice cake in Korea. Multifunctional portable grinder was used for making sulgidduk and investigated the characteristic changes of rice powder for deciding the proper particle size of rice powder. Operation times for grinding the water absorbed swelled rice were 10, 20, 30 and 40 seconds. Moisture contents of rice powder and sulgidduk showed an increasing tendency with an increase of operation times for grinding. Springiness showed significant differences according to the operation times. Cohesiveness was decreased severely after 40 seconds grinding. Chewiness showed high after 20 seconds grinding in all groups; however, decreased after 40 seconds grinding and showed similar chewiness of the control group. Fracturability also showed severe increased tendency after 20 seconds grinding and decreased after 30 seconds grinding. Strength and hardness showed significant differences; they were increased until 30 seconds and severely decreased after 40 seconds grinding. L values showed significant differences in all the groups (p≤0.05). The a and b values did not show any differences in all groups. Overall sensory evaluations, such as colors, flavors and texture, were increased with operation times for grinding and showed significant differences among the groups (p<0.05). As a result of this study, 40 seconds grinding times were the best condition for making sulgidduk, using by multifunctional grinder.
        4,000원
        615.
        2012.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study investigated the effects of the diet with Cucurbita moschata (CM), adlay seed (AS), and Cudrania tricuspidata leaf (CTL) mixed-powder on the visceral fat, fecal amount, and serum lipid profiles in rats fed a high-fat diet (HFD). The mixed ratio of CM, AS, and CTL as a functional food ingredient was 1:1:1 on a weight basis. Male Sprague-Dawley rats were fed a high-fat diet (D12492; 45 kcal fat) for 5 weeks during the first phase. In the second phase, which lasted 5 weeks, the rats were divided into six experimental groups. The groups were: a high-fat diet group as a control during the 10 weeks of experimental period; and a high-fat diet with 5, 10, 15, 20, and 30% mixed powder supplement group. The adipose tissue (RFP, EFP) weights were significantly decreased in the 20% and 30% mixed powder supplement groups than in the HFD group (p<0.05). The fecal weight produced by the 15%, 20%, and 30% mixed powder supplement groups was significantly increased during the second phase compared to the first phase (p<0.05). In terms of serum lipids, TG (triglyceride) content was decreased in the 10% and 15% mixed-powder supplement groups. The blood glucose levels were significantly decreased in all experimental diet supplement groups than in the HFD group (p<0.05). The findings show that the high supplement groups could improve the visceral fat accumulation, fecal amount, and blood glucose content compared to the HFD group.
        4,000원
        616.
        2012.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was performed in order to investigate the quality characteristics of sponge cake made with Laminaria japonia powder. To evaluate the physical and sensory analysis, Laminaria japonia powder was added to wheat flour in various ratio (3, 5, 7, 9%, w/w). The specific gravity and loss rate increased with the addition of Laminaria japonia powder. The crude protein and ash levels in the sponge cakes increased linearly with the addition of 0 9 g of Laminaria japonia powder/100 g of wheat flour. For the crumb color values, lightness (L) and yellowness (b) decreased with the addition of Laminaria japonia powder, whereas redness (a) significantly increased (P<0.05). In the texture analysis, the hardness, gumminess and chewiness were increased; however, the cohesiveness and resilience were reduced by the addition of Laminaria japonia powder. When the sensory characteristics were evaluated, 5% Laminaria japonia sponge cake showed the highest sensory properties, except for color. Therefore, the results suggested that 5% Laminaria japonia sponge cake could be helpful in improving the physical quality as well as the taste.
        4,000원
        617.
        2012.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The objective of this study was to determine the optimum mixing ratio of Opuntia humifusa powder and sugar in the preparation of muffin. The optimal sensory composite recipe was determined by following the central composites for muffin with different levels of Opuntia humifusa powder (A) and sugar (B). The analysis was performed using the response surface methodology, and the sensory evaluation was performed with the data. Ten experimental recipes, including two with reference points in the composition, were selected. The compositional and functional properties were measured, and the physical and sensory values were applied to the mathematical models. Perturbation plots showed the effects of each ingredient on the final product. Measurements showed significant values in lightness (p<0.05), sweetness (p<0.05), hardness (p<0.05), gumminess (p<0.05) and cohesiveness (p<0.01). The sensory measurements showed significant values in color (p<0.05), flavor (p<0.05), appearance (p<0.05), softness (p<0.05) and overall quality (p<0.05). Based on the numerical and graphical methods, the optimal formulation was determined to be 6.10 g of Opuntia humifusa powder and 82.61 g of sugar.
        4,200원
        618.
        2012.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was conducted to examine the applicability of muffins and the optimal ratio of batter mixture by adding mugwort with various functions and physiological active substances. In result of examining the quality characteristics of muffins after adding frozen-dried mugwort powder by 0%, 1%, 3%, 5%, or 7%, the moisture retaining capacity of muffin batter was lowest with MPM0, the control group, and the deposition was highest at 17.94 ㎖ with MPM0. The pH value of muffin batter was highest at 8.62 with MPM0 and moisture decreased significantly (p<0.001) when more mugwort powder was added to the sample. The brightness increased significantly (p<0.001) when the amount of frozen-dried mugwort powder decreased and redness and yellowness decreased when the addition of mugwort powder increased. The height and volume of mugwort muffins were lowest at 4.75 ㎝ and 135.69 ㎖ with MPM7 with the greatest value of frozen-dried mugwort powder. The loss at baking of mugwort muffins was lowest at 2.27% with MPM7. The hardness of mugwort muffins was highest with MPM7 with the highest mugwort powder content. Coagulation and resilience was highest at 0.64 with the MPM0 control group and the chewiness increased significantly (p<0.001) with greater amount of frozen-dried mugwort powder. The appearance of mugwort muffins was highest at 6.1 with MPM5 and the most preferable color and flavors were found with MPM3. Tenderness was highest with the MPM0 control group. Overall preferability was highest with MPM3 with 3% frozen-dried mugwort powder. When adding frozen-dried mugwort powder to muffins, the 3% and control groups mostly showed the highest values, whereas the 5% group and higher groups showed lower values.
        4,000원
        619.
        2012.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was conducted to investigate rheological and sensory characteristics of fish paste prepared with Curcuma longa L. powder (0, 1, 3, 5, 7%). The moisture content of the fish paste ranged from 71.35 to 72.97%. Increasing the amount of Curcuma longa L. powder in the fish paste tended to decrease the pH value and the folding test good score in all samples. Increasing the amount of Curcuma longa L. powder in the fish paste also tended to decrease the lightness (L) in the hunter color value, but to increase the redness (a) and yellowness (b). For the textural characteristics, the addition of Curcuma longa L. powder increased the strength and decreased the springiness. In a sensory evaluation, the addition of 3% Curcuma longa L. powder had the best score in taste and overall preference. Therefore, this results suggest that adding 3% Curcuma longa L. powder would be feasible for making Curcuma longa L. fish paste.
        4,000원
        620.
        2012.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study examined the quality characteristics of Gondre tofu containing 0, 0.1, 0.2, and 0.3% Cirsium setidens powder. Quality and sensory tests of Gondre tofu were performed. The yield rate of tofu decreased with the addition of Cirsium setidens powder. The pH of tofu decreased after the addition of Cirsium setidens powder. During 8 days storage, the addition of Cirsium setidens powder to tofu did not effectively inhibit the number of total aerobic bacteria. The L, a and b values of tofu decreased with increasing amount of Cirsium setidens powder added. In the texture properties, the hardness, cohesiveness, gumminess and brittleness increased, whereas the springiness decreased. The results of sensory evaluation showed that tofu containing 0, 0.1, and 0.2% Cirsium setidens powder had a higher taste, texture preference and overall acceptability than 0.3% Cirsium setidens powder. Therefore, the addition up to 0.2% Cirsium setidens powder positively affects the sensory evaluation of Gondre tofu. The addition 0.2% Cirsium setidens powder might be considered the most appropriate choice for manufacturing Gondre tofu.
        4,000원