• Title/Summary/Keyword: Substitution

Search Result 3,694, Processing Time 0.039 seconds

Studies of Element Substitution on Superconductivity in Bi-Sr-Ca-Cu-O Oxides (Bi계 치환 고온 초전도체)

  • 권오흥;박천제
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
    • /
    • 2000.11a
    • /
    • pp.124-128
    • /
    • 2000
  • The high Tc phase disappeared and low Tc phase increased in the substitution of transition elements for Bi ions. The high Tc phase decreased in the substitution of Si and Sn for Bi ions. The high Tc phase increased in the substitution of Sb, As and P which were the same group of Bi for Bi ions. The substitution of P ions was the most effective and then the high Tc phase was formed in large quantity by replacing Bi ions with 30% of P ions.

  • PDF

A Study on the Electrical and Optical Characteristics of CLN-PZT Ceramics (CLN-PZT 세라믹스의 전기, 광학 특성에 관한 연구)

  • Kang, Won-Koo
    • Proceedings of the KIEE Conference
    • /
    • 1988.07a
    • /
    • pp.799-801
    • /
    • 1988
  • This paper was studied on the effects of Ca-La-Nb substitution and Zr/Ti ratio variation to Pb(Zr, Ti)$O_3$ system on structural, electrical, optical and sound level characteristics in order to develope the piezoelectric and electrooptic ceramic devices. Also the specimens were prepared by the two stage sintering technique. The molecular formular was X($CaO{\cdot}1/4La_{2}O_{3}{\cdot}1/4Nb_{2}O_{5}){\cdot}(1-X)Pb(Zr_{Y}Ti_{1-Y})O_{3}$(x=100X, y=100Y), and the variation of x was $6{\sim}12$, y was 60${\sim}$49 and second stage sintering time was 20${\sim}$40 hours. The experimental results obtained from this study are as follows : 1. The density was decreased, the grain size was increased according to increase of Ca-La-Nb substitution. 2. The crystal structure was rhombohedral in composition 6/60/40, and the crystal structure was tetragonal and cubic according to increase of Ca-La-Nb substitution. 3. The Ca substitution of PZT system enhanced the sintering property. The Pb site vacancy resulting from the substitution of La-Nb increased the dielectrical constant, the piezoelectric charge constant, the dielectric loss and decreased the coercive field. 4. The resistivity of PZT system which has the P type conduction mechanism increased according to substitution of La-Nb because of the substituent acting as donor. 5. The PZT ceramics varied from ferroelectric substance according to increase of Ca-La-Nb substituent. The coercive field and saturation remanent polarization decreased, and at last straight line according to increase of La-Nb substitution. 6. The amount of Ca-La-Nb substitution to improve the light transmittance of speciment was 10 mol%, the Zr/Ti ratio was 49/51, and the second stage sintering time was 40 hours. 7. According to Ca-La-Nb substitution, the specimens was to be transparent. The 7.5/51/49 specimen was suitable for transparent sound vibrator because it had 58% light transmittance (thick 0.2[mm], wave length 700[mm]) and 48% electromechanical coupling factor.

  • PDF

Effects of Substituting Concentrates with Dried Leftover Food on Growth and Carcass Characteristics of Hanwoo Steers

  • Paek, B.H.;Kang, S.W.;Cho, Y.M.;Cho, W.M.;Yang, C.J.;Yun, S.G.
    • Asian-Australasian Journal of Animal Sciences
    • /
    • v.18 no.2
    • /
    • pp.209-213
    • /
    • 2005
  • This study was conducted to determine the optimum substitution level of dried leftover food (DLF) in formula feed for Hanwoo (Korean Native Cattle) steers. A total of forty growing steers were assigned to 5 treatments based on substitution level of DLF (at 0, 25, 50, 75 and 100% level of formula feed). The experiment was carried out with growing steers from 6 months of age to 24 months of age. Average daily gain (ADG) was not affected by DLF substitution level up to 75% of formula feed. However ADG decreased at 100% substitution level. Daily feed intakes were similar among treatments but the amount of feed per 1 kg gain increased with increasing substitution level of DLF. Dressing percentage was around 62% in all treatments without any significant differences. Proportion of quality beef higher than grade 1 was the greatest from animals fed 25% substitution level of DLF. Economic efficiency for Hanwoo steer operator was the highest with 50% substitution level of DLF.

A Deterministic Model for Optimal Pricing Decisions with Price-Driven Substitution (가격차에 의해 발생하는 수요대체효과를 고려한 정태적 최적가격결정 모형 수립)

  • Kim, Sang-Won
    • Journal of the Korean Operations Research and Management Science Society
    • /
    • v.33 no.1
    • /
    • pp.1-17
    • /
    • 2008
  • Market segmentation is a key strategic factor in increasing the expected profits, especially in the practice of revenue management. A manufacturing firm should manage both manufacturing quantities and pricing decisions over its segmented markets to maximize the expected profits, setting different price for each different segment. Also, market segments should be kept separate in order to prevent demand leakages between different market segments. In fact, even though the markets for different products are firmly segmented, it is not easy to keep separate segmentation because many products might be substitutable by customer buying behavior. That is, customers respond to price changes by purchasing other market's products instead of purchasing the originally requested products, which causes demand substitution effect ; This kind of substitution is referred to as price-driven substitution. Therefore, decisions on optimal prices should take into account the differences in customers' valuation of the different products. We consider a deterministic model for deciding optimal prices in the presence of price-driven substitution, and we compare both symmetrical-and asymmetrical-type demand substitutions between two segmented markets. The objective of this study is to develop analytical and numerical models to examine the impact of price-driven substitution on the optimal price levels and the total expected profits.

Quality Characteristics of American Waffle with Kamut Whole Wheat Flour (카무트 전립분을 대체한 아메리칸 와플의 품질 특성)

  • Kim, Mun-Yong;Kim, Ji-Hyun;Chun, Soon-Sil
    • The Korean Journal of Food And Nutrition
    • /
    • v.33 no.2
    • /
    • pp.183-193
    • /
    • 2020
  • The study was to investigate the quality characteristics of American waffles substituted with 0, 25, 50, 75, and 100% of kamut whole wheat flour (KWF). The KWF samples had maintaining the specific gravity of the batter until the 25% substitution. The spreadability decreased as the ratio of the KWF increased, and the pH of the 100% substitution sample were the lowest. The KWF samples had increasing baking loss rates until the 75% substitution while decreasing the water activity. Lightness and yellowness significantly decreased with increasing the KWF while redness increased. Hardness, chewiness, and gumminess of the 25% substitution sample were the highest, while the springiness and resilience were maximum with the 100% substitution. The KWF samples had increasing overall acceptability, acceptability of color, flavor, and texture until the 50% substitution. The characteristics intensity rating of crust color, bran flavor, and sweetness increased with increasing the KWF. The KWF samples had significantly higher crispiness than the control group. The frequency of the bran flavor, sweetness, nuttiness, and unpleasant increased while the egg and milk flavor, and flour taste decreased. These results suggest that the substitution of the 25~50% KWF could be the optimal to improve the quality characteristics of American waffles.

Substitution effects of enzymatically saccharified Korean rice wine lees powder on skim milk in yogurt fermentation (요구르트 발효에서 효소로 당화시킨 주박 분해물의 탈지분유 대체 효과)

  • In, Man-Jin
    • Journal of Applied Biological Chemistry
    • /
    • v.62 no.3
    • /
    • pp.299-304
    • /
    • 2019
  • Yogurt was prepared with different substitution ratio [10, 20, 30, and 50% (w/w)] of skim milk with enzymatically saccharified Korean rice wine lees powder (eKRWLP) and fermented with commercially available mixed lactic acid bacteria (Bifidobacterium longum, Lactobacillus acidophilus, Streptococcus thermophilus) at $40^{\circ}C$ for 18 h. Fermentation characteristics were evaluated in terms of acid production (pH and titratable acidity) and viable cell counts of lactic acid bacteria. The pH of yogurts decreased with increasing eKRWLP substitution ratio of skim milk. After 12 h fermentation, titratable acidities of eKRWLP substitution and control (yogurt made without eKRWLP) were 0.84~1.04% and 0.93%, respectively. The titratable acidities of yogurts prepared with 10 and 20% substitution ratio increased than that of the control yogurt, but titratable acidities of yogurts of 30 and 50% substitution ratio decreased. After 9 h fermentation, the number of viable lactic acid bacterial cell were increased to 8.18~8.24 log CFU/g in all yogurts. In sensory evaluation, there were similar preference for eKRWLP yogurts prepared with 10 and 20% substitution ratio and the control. When eKRWLP substitution and control yogurts fermented for 9 h were incubated at $4^{\circ}C$, their pHs and titratable acidities were slightly changed but the number of viable lactic acid bacteria were well maintained above $10^7CFU/g$ for 11 days in yogurts prepared with 10 and 20% substitution ratio among eKRWLP substitution yogurts. These results suggest that eKRWLP can be used as substituent of skim milk and the optimum substitution ratio is around 10~20%.

Alkylation and Allylation of Lithium Arylborates Factors Affecting the Di/Mono Substitution Ratio$^\dag$

  • Lee, Ho-Seong;Song, Yang-Sup;Lee, Dong-Doo
    • Bulletin of the Korean Chemical Society
    • /
    • v.8 no.5
    • /
    • pp.424-425
    • /
    • 1987
  • Alkylation and allylation of arylborates give mono(ipso) and/or di(ortho and ipso) substitution products. Those factors which promote polarization or ionization of alkylating agents favor di substitution. The ${\sigma}$-type(ipso) substitution reaction of arylborates involves direct interaction of the carbon-boron bonds rather than predissociation of arylborates into aryllithiums and boranes.

Effect of Substitution of Recycled Fine Aggregate on Concrete Performance. (재생잔골재 대체가 콘크리트 성능에 미치는 영향)

  • 정용일;양은익;정기철;김학모;최중철
    • Proceedings of the Korea Concrete Institute Conference
    • /
    • 2002.10a
    • /
    • pp.233-238
    • /
    • 2002
  • In this paper, the characteristics of fresh and hardened recycled concrete were experimentally compared to investigate the applicability of the recycled fine aggregates with the substitution ratio. Test results show that the workability of the recycled concrete decreases with the increment of substitution ratio of the recycled fine aggregates except for type-D case which has a lower absorption ratio. Also air content was increased with increasing substitution ratio. It was found that the compressive strength and elastic modulus of recycled concrete were decreased with increasing substitution ratio of the recycled fine aggregates. And, the superplasticizer was more effective on the workability recovery of the recycled concrete.

  • PDF

Ionic Liquids: An Environmentally Friendly Media for Nucleophilic Substitution Reactions

  • Jorapur, Yogesh R.;Chi, Dae-Yoon
    • Bulletin of the Korean Chemical Society
    • /
    • v.27 no.3
    • /
    • pp.345-354
    • /
    • 2006
  • Ionic liquids are alternative reaction media of increasing interest and are regarded as an eco-friendly alternatives, of potential use in place of the volatile organic solvents typically used in current chemical processing methods. They are emerging as the smart and excellent solvents, which are made of positive and negative ions that they are liquids near room temperature. The nucleophilic substitution reaction is one of the important method for inserting functional groups into a carbon skeleton. Many nucleophilic substitution reactions have been found with enhanced reactivity and selectivity in ionic liquid. In this review, some recent interesting results of nucleophilic substitution reactions such as hydroxylations, ether cleavages, carbon-X (X= carbon, oxygen, nitrogen, fluorine) bond forming reactions, and ring opening of epoxides in ionic liquids are discussed.

Multiplexed Optical Correlation Filter for Optical Parallel Addition Based on Symbolic Substitution with Redundant Binary Number (기호치환을 기초로 한 잉여 이진수 광병렬 가산용 다중 광상관 필터)

  • 노덕수;조웅호;김정우;이하운;김수중
    • Journal of the Korean Institute of Telematics and Electronics B
    • /
    • v.33B no.3
    • /
    • pp.109-119
    • /
    • 1996
  • We propsoed a multiplexed optical correlation filter method for an optical parallel addition based on symbolic substitution. In the proposed mthod, we used redundant binary number which was easy to minimize the number of the symbolic substitution rules. We chose MACE filter which had very low sidelobes and good correlation peak compared with SDF filter as the optical correlation recognition filter and encoded input numbers properly to increase the discrimination capability. In order to minimize the number of symbolic substitution rules, sixteen input patterns were divided into six groups of the same addition results and six filters for recognizing the input patterns were used. these filters were multiplexed in two MMACE filter planes and the corresponding substitution method was proposed. Through the computer simulation, we confirmed the proposed method was suitable to implement the optical parallel adder.

  • PDF