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        검색결과 572

        242.
        2011.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The influence of sulfate on the selective catalytic reduction of on the Ag/ catalyst was studied when was used as a reducing agent. Various preparation methods influenced differently on the activity. Among the methods, cogelation precipitation gave best activity. When sulfates were formed on the surfaces of samples prepared by impregnated and deposition precipitation, activity was enhanced as long as suitable forming condition is satisfied. The major sulfate formed in Ag/ catalyst was the aluminum sulfate and it seems that this sulfate acted as a promoter. When Mg was added to the Ag/ catalyst it promoted activity at high temperature. Intentionally added sulfate also enhanced activity, when their amount was confined less than 3 wt%.
        4,000원
        243.
        2011.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 느타리, 노랑느타리, 분홍느타리, 버들송이의 건조분말을 이용하여 두부에 적합한 첨가량을 구명하고자 수행되었다. 버섯 첨가량에 따른 두부수율은 대조(무첨가)구에 비해 느타리 3~12%, 노랑느타리 3, 6%, 분홍느타리 3, 6%, 버들송이 3, 6% 첨가시에 수율이 높았고, 버들송이는 9%이상 첨가시 고형이 되지 않았다. 경도는 느타리버섯 3, 6%, 노랑느타리 3%, 분홍느타리 3%, 버들송이 3% 첨가시에 높았다. 버섯의 첨가량이 많을수록 명도는 낮아졌으며, 적색도는 분홍느타리 첨가비율이 높을수록 증가 하였지만 노랑느타리는 황색도가 증가하지 않았다. 버섯두부의 기호도조사결과 느타리버섯은 6~12%, 노랑느타리버섯은 3%, 분홍느타리 3%, 버들송이 3, 6% 첨가시 기호도가 우수한 것으로 나타났다. 이상의 결과 수율과 경도가 높고 기호도가 우수한 두부에 제조에 적합한 버섯의 적정 첨가량은 느타리버섯 6%, 노랑느타리, 분홍느타리, 버들송이 각3%로 판단된다.
        4,000원
        244.
        2010.12 KCI 등재 구독 인증기관·개인회원 무료
        This study was conducted to evaluate the feeding value of the spent mushroom (Pleurotus eryngii) substrates (SMS) in laying hens (Hy-Line Brown). The fresh spent mushroom (Pleurotus eryngii) substrates collected from the DOJUN farm were fermented with Bacillus subtilis EJ3 for 2 weeks. A total of twenty-four laying hens were fed corn-soy based experimental diets containing 0% (control), 5% (T1), 10% (T2) and 15%(T3) fermented SMS for 7 weeks. There were no significant differences among the treatments in egg production, egg weight, egg mass, feed conversion and viability during the experimental period. Feed intake was significantly lowered in control (118.3 g) than T1 (121.9 g), T2 (120.3 g) and T3 (122.4 g). There were no significant differences among the treatments eggshell breaking strength, thickness and haugh unit, whereas the yolk color of T1, T2 and T3 were significantly heavy than T0. The palatability of boiled meat was significantly better in the T3 laying hens than in the T0 laying hens. In conclusion, fermented SMS can be used as resource of feed in laying hen feed at 5.0-15% level without effect on performance and egg qualify.
        246.
        2010.09 구독 인증기관 무료, 개인회원 유료
        Current developments in IVF and animal cloning have resulted in increasing demand for large quantities of oocytes and ovarian follicles at specific stages of development. These medical and scientific needs may be met by developing an optimal culture system for preantral follicles. In this study, we investigated the growth of porcine preantral follicle cultures in different media and in the presence and absence of serum. Follicles were manually dissected from ovaries obtained from prepubertal gilts at a local slaughterhouse, and cultured for 3 days in M199 or NCSU23 medium supplemented with porcine FSH, transferrin, L-ascorbic acid and insulin. Follicle diameters were measured on day 1 and 3 of culture. In Experiment 1, the effect of supplementing culture medium with fetal calf serum (FCS) on porcine preantral follicle growth was examined. In the group of cultures supplemented with FCS, follicle diameter after 3 days of culture, survival rate and antrum formation rate in the FCS group were significantly higher than those of the control group. In Experiment 2, the effects of culture medium (M199 and NCSU23) on follicle growth were compared. Follicle diameters were increased in the M199 group, compared with those in NCSU23 (p<0.05), but we observed no significant differences in survival and antrum formation rates between cultures grown in the two media. In conclusion, supplementation of the culture medium with serum enhances preantral follicle growth and antrum formation, and M199 is superior to NUSU23 for porcine preantral follicle culture in vitro.
        4,000원
        247.
        2010.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Purpose : In this study, we manufactured functional contact Jens using 2-hydroxyethyl methacrylate, N-vinyl-2-pyrrolidone, methyl methacrylate and nano Au, platinum with antibiosis. Methods : The resulting mixture was copolymerized by heating at 70"C for about 40 minutes, at 80"C for about 40 minutes, and finally at wo·c for about 40 minutes. Results : The physical properties of the produced polymers were measured as followings. The refractive index of 1.431-1.432, water content of 38.58-39.53%, visible transmittance of 89.8- 91.5%, and oxygen transmissibility of 6.5934 xl0-9 cm/s ml Oz/ml xmmHg were obtained. Conclusions : In this study, we manufactured high-performance ophthalmic material containing nano gold and pJatinum which could protect eye from envirorunental factors. lt is judged that functional polymer materia! with the physical properties required to produce contact Jens was made.
        4,000원
        248.
        2010.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        삼백초 분말의 첨가량을 0-6%로 달리하여 쿠키를 제조한 후 물리화학적 품질 및 관능적 품질특성을 측정하고 각 특성사이의 상관관계를 살펴보았다. 삼백초 분말 첨가량이 증가함에 따라 쿠키의 두께 및 밀도는 유의적으로 증가하였으나(p<0.05), 반죽의 구께 및 밀도에는 영향을 미치지 않는 것으로 나타났다(p>0.05). 반죽과 쿠키의 pH는 삼백초 분말 첨가량이 증가함에 따라 현저하게 감소하였으며, 색 특성 중 명도와 황색도 역시 현저하게 감소한 반면 적색도는 증가하는 경향을 나타내었다. 관능검사 결과, 경도를 제외한 맛, 향미, 색 등의 강도는 분말의 첨가량이 증가함에 따라 유의적으로 증가하여 6% 첨가군이 가장 높게 평가되었다(p<0.05). 한편 상관분석결과 삼백초 분말 첨가 수준은 대부분의 물리화학적 및 관능적 품질특성과 유의적인 상관관계를 나타내어, 삼백초 분말 첨가가 반죽 및 쿠키의 전반적인 품질특성에 상당한 영향을 미치는 것으로 나타났다.
        4,000원
        249.
        2010.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        For the aim of low-temperature co-fired ceramic microwave components, sintering behavior and microwave properties (dielectric constant , quality factor Q, and temperature coefficient of resonant frequency ) are investigated in [BCZN] ceramics with addition of . The specimens are prepared by conventional ceramic processing technique. As the main result, it is demonstrated that the additives () show the effect of lowering of sintering temperature and improvement of microwave properties at the optimum additive content. The addition of 0.25 wt% lowers the sintering temperature to utilizing liquidphase sintering and show the microwave dielectric properties (dielectric constant = 75, quality factor = 572 GHz, temperature coefficient of resonance frequency ). The estimated microwave dielectric properties with addition (increase of , decrease of , shift of to negative values) can be explained by the observed microstrucure (sintered density, abnormal grain structure) and possibly high-permittivity (BZN) phase determined by X-ray diffraction.
        4,000원
        250.
        2010.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The objective of this study was to examine the quality characteristics and antioxidant activity of yogurt containing hot water extract from maca. Four different levels (0, 4, 8, 12%) of maca extract were added to milk followed by fermentation with lactic acid bacteria at 37℃ for 12 hrs, and then the physicochemical properties of the samples were investigated. During 7 days of storage at 4±1℃, the acid production (pH and titratable acidity) of the yogurt increased with the addition of maca extract. The Hunter L value (lightness) decreased, while the b value (yellowness) increased as the maca extract level in the yogurt increased. Viable cell counts were not significantly different among the samples. The results of consumer acceptance tests showed that no significant differences in overall acceptability were observed between the yogurts containing 4% and 8% of maca extract and a control yogurt. The yogurt containing maca extract exhibited higher DPPH radical and superoxide anion radical scavenging activities than the control yogurt over the storage period.
        4,000원
        251.
        2010.04 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Zirconium diboride (ZrB2) and mixed diboride of (Zr0.7Ta0.3)B2 containing 30 vol.% silicon carbide (SiC) composites were prepared by hot-pressing at 1800˚C. XRD analysis identified the high crystalline metal diboride-SiC composites at 1800˚C. The TaB2 addition to ZrB2-SiC showed a slight peak shift to a higher angle of 2-theta of ZrB2, which confirmed the presence of a homogeneous solid solution. Elastic modulus, hardness and fracture toughness were slightly increased by addition of TaB2. A volatility diagram was calculated to understand the oxidation behavior. Oxidation behavior was investigated at 1500˚C under ambient and low oxygen partial pressure (pO2~10-8 Pa). In an ambient environment, the TaB2 addition to the ZrB2-SiC improved the oxidation resistance over entire range of evaluated temperatures by formation of a less porous oxide layer beneath the surface SiO2. Exposure of metal boride-SiC at low pO2 resulted in active oxidation of SiC due to the high vapor pressure of SiO (g), and, as a result, it produced a porous surface layer. The depth variations of the oxidized layer were measured by SEM. In the ZrB2-SiC composite, the thickness of the reaction layer linearly increased as a function of time and showed active oxidation kinetics. The TaB2 addition to the ZrB2-SiC composite showed improved oxidation resistance with slight deviation from the linearity in depth variation.
        4,000원
        252.
        2010.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The effects of La addition to Ni/CeO2 methane partial oxidation catalysts were investigated. Catalysts were prepared by the impregnation and urea methods. In the preparation of catalysts, La content was changed from 1 wt% to 3wt%. Catalysts that contain 2wt% La showed the highest methane conversion of about 80% and CO selectivity of 84% and H2 selectivity of 70%. This result may be stemmed from that, when La content is 2wt%, a fluorite oxide-type structure is well formed and carbon deposition is also decreased. Among the catalysts, 2.5wt% Ni/Ce(La)Ox showed the highest catalytic activity. From the experiment of changing reaction temperature with 2.5wt% Ni/Ce(La)Ox catalyst, it was found that the optimum reaction temperature is 750℃ and at this temperature methane conversion was about 90%, CO and H2 selectivities were 94 and 80%, respectively.
        4,000원
        253.
        2010.02 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Glass-ceramics were fabricated by heat-treatment of glass obtained by melting a coal bottom ash with Li2O addition. The main crystal grown in the glass-ceramics, containing 10 wt% Li2O, was β-spodumene solid solution, while in Li2O 20 wt% specimen was mullite, identified using XRD. The activation energy and Avrami constant for crystallization were calculated and showed that bulk crystallization behavior will be predominant, and this expectation agreed with the microstructural observations. The crystal phase grown in Li2O 10 wt% glass-ceramics had a dendrite-like shaped whereas the shape was flake-like in the 20 wt% case. The thermal expansion coefficient of the Li2O 10 wt% glass-ceramics was lower than that of the glass having the same composition, owing to the formation of a β-spodumene phase. For example, the thermal expansion coefficient of Li2O 10 wt% glass-ceramics was 20×10-7, which is enough for application in various heat-resistance fields. But above 20 wt% Li2O, the thermal coefficient expansion of glass-ceramics, on the contrary, was higher than that of the same composition glass, due to formation of mullite.
        4,000원
        254.
        2010.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The unique features of spark plasma sintering process are the possibilities of a very fast heating rate and a short holding time to obtain fully dense materials. -SiC powder with 0, 2, 6, 10 wt% of -SiC particles (seeds) and 4 wt% of Al-B-C (sintering aids) were spark plasma sintered at for 10 min. The heating rate, applied pressure and sintering atmosphere were kept at , 40 MPa and a flowing Ar gas (500 CC/min). Microstructural development of SiC as function of seed content and temperature during spark plasma sintering was investigated quantitatively and statistically using image analysis. Quantitative image analyses on the sintered SiC ceramics were conducted on the grain size, aspect ratio and grain size distribution of SiC. The microstructure of SiC sintered up to consisted of equiaxed grains. In contrast, the growth of large elongated SiC grains in small matrix grains was shown in sintered bodies at and the plate-like grains interlocking microstructure had been developed by increasing sintering temperature. The introduction of -SiC seeds into -SiC accelerated the grain growth of elongated grains during sintering, resulting in the plate-like grains interlocking microstructure. In the -SiC seeds added in -SiC, the rate of grain growth decreased with -SiC seed content, however, bulk density and aspect ratio of grains in sintered body increased.
        4,000원
        255.
        2009.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was designed to estimate the effect of ethanol addition on shelf-life extension and changes in growth of total aerobic bacteria in fresh wet noodles. The wet noodle was made with addition of 0, 1 and 2% ethanol. During the storage at 10oC, wet noodles were monitored changes in the total numbers of aerobic bacteria. A 6 log cfu/g was applied as a standard for microbiological quality of foods. As a result, the shelf-lifes of wet noodle with addition of ethanol at the standard were 9.17 days at no ethanol, 15.02 days at 1% ethanol and 27.03 days at 2% ethanol. The respective percentage increases in the shelf-life observed at both 1 and 2% ethanol addition were 63.8% and 194.8% comparing with no ethanol treatment. Consequently, addition of ethanol into fresh wet noodle inhibited growth of total aerobic bacteria and extended shelf-life.
        3,000원
        256.
        2009.12 구독 인증기관 무료, 개인회원 유료
        This study was conducted to investigate the effects of herbs (dill weed, fennel seed and rosemary) on color stability and lipid oxidation of ground pork patties during storage at 2oC and −20oC. Lipid oxidation was determined by the thiobarbituric acid reactive substances (TBARS) method. Fennel seed was identified as being the most effective ingredient in terms of meat redness (Hunter a-values) during storage at 2oC (p<0.05). Patties treated with rosemary had lower Hunter a-values than control, and dill weed was the least beneficial in influencing meat redness, having significantly lower a-values than control patties. During frozen storage at −20oC, no significant differences in a-values were observed between the control patties and those treated with fennel seed. Patties treated with rosemary had lower a-values than control and patties with dill weed had negative a-values throughout storage. The cooking process increased Hunter L-values and decreased a-values in all patty samples. TBARS values increased during storage. Rosemary displayed excellent antioxidative activity as evidenced by the completely inhibition of TBARS formation of cooked pork patties. Dill weed and fennel seed also exerted an intermediate but significant antioxidant effect during storage (p<0.05).
        4,000원
        257.
        2009.11 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        BaTiO3/epoxy composites have been widely investigated as promising materials for embedded capacitors in printed circuit boards. It is generally known that the dielectric constant (K) of the BaTiO3/epoxy composites increases with improvement of the dispersion of BaTiO3 particles in the epoxy matrix that comes from adding surfactant. The influences of surfactant addition on the dielectric properties of the BaTiO3/epoxy composites are reported in the present study. The dielectric constant of the BaTiO3/epoxy composites is not significantly affected by the surfactant addition. However, the temperature coefficient of capacitance increases and the peel strength decreases as the amount of added surfactant increases. The influences of surfactant addition on the dielectric properties of the neat epoxy are also very similar to those of the BaTiO3/epoxy composites. The residual surfactant in the BaTiO3/epoxy composites affects the temperature coefficient of capacitance and the peel strength of the epoxy matrix, which in turn affects the temperature coefficient of capacitance and the peel strength of the BaTiO3/epoxy composites.
        4,000원
        258.
        2009.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        목적: 누진가입도렌즈 피팅용으로 개발된 이동식 코받침(Moving Nose Pad, MNP)의 임상성능을 평가하여 누진가입도렌즈의 피팅실무에 효과적인 지침을 제시하고자 하였다. 방법: 현재 누진가입도렌즈를 착용하며 본 연구의 취지에 동의한 55명(남자 48명과 여자 7명)(평균 나이 53.1±4.6세)을 선정하였다. 현재 착용 중인 안경의 피팅 상태와 사용 만족도를 평가하고, MNP로 교체했을 때 피팅상태의 변화를 측정한 다음 2주 동안 사용한 후 자각적 만족도를 평가하였다. 결과: MNP로 교체된 안경을 착용하고 원거리와 근거리를 주시할 때 피팅상태의 변화는 피팅기준점높이와 정점간거리에서 유의한 차이를 보였다. MNP로 교체된 안경을 2주 동안 착용한 후 자각적 만족도를 조사한 결과, 47%가 컴퓨터 작업을 할 때 흐려 보임을 경험했고 그 가운데 95%는 안경을 위쪽으로 이동시켰을 때 선명한 시력을 얻었다. 82%가 독서할 때 흐려 보임을 경험했고 그 가운데 96%는 안경을 위쪽으로 이동시켰을 때 선명한 시력을 얻었다. MNP로 교체된 안경에 적응하는 시기는 86%가 1주일 이내라고 응답하였다. 결론: MNP로 교체된 안경의 피팅상태가 유의한 변화를 보였지만, MNP로 인한 적응기간이 별도로 필요하지 않으며, 누진가입도렌즈에 적응하기 어려운 불편감을 경감시키거나 추가로 발생할 수 있는 비용을 절감하는 효과가 있을 것으로 생각된다.
        5,400원
        259.
        2009.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        느타리버섯의 배지에 철, 고춧가루, 은행잎을 첨가하였을 때 버섯의 생육과 생리활성을 분석한 결과는 다음과 같다. 수량은 춘추 품종에 철 34.9g을 첨가하였을 때 144g으로 가장 높았고, 나머지 품종간에는 차이가 없었으며, 34.9g 및 174.5g 처리시 17.4g 처리에 비해 수량이 높은 경향이었다. 자실체와 배지에 포함된 무기물의 함량은 종류별로 차이가 있었으며, 배지중 철의 함량이 증가하여도 자실체내의 철의 함량은 0.31∼0.43mg/kg으로 거의 일정하게 유지되었다. 배지에 포함된 고춧가루의 함량이 많아질수록 자실체에 포함된 캡사이신의 함량도 많아졌으며, 수한품종에서 6mg/100g으로 가장 많이 전이되었다. 철이나 고추를 첨가한 배지에서 재배한 버섯에서 페놀성 화합물의 함량이 높게 나타났으며, 항산화력과 총 페놀성 화합물 함량, 환원력과 총페놀성 화합물 함량, 금속이온 제거능과 페놀성 화합물의 함량 간에는 서로 영향을 미치지 않는 경향이었다. Macrophage 활성화능은 수한 품종이 다른 품종에 비해 높은 경향이었다.
        4,000원
        260.
        2009.08 구독 인증기관·개인회원 무료
        This study investigated the influences of the addition of lactic acid bacteria inoculants and an enzyme during the crush processing of com silage on the nutritive value, nutrient intake and aerobic deterioration. The fermentation quality of the silages showed that although all of the silages were of good quality, the V-score of U was 91.0 points and significantly lower than those of other silages (P<0.01). On the chemical composition of silages, the crude protein concentration of U was 7.1%DM and significantly lower than those of other silages (P<0.05). On the digestibility, the nutritive value and nutrient intake did not significantly differ among the silages examined. After silo opening, a rapid rise in heat was seen from the 6th after opening for 11C38 and SLA, and from the 9th in U and SL, respectively.