• Title/Summary/Keyword: $C_0$

Search Result 59,618, Processing Time 0.076 seconds

Piezoelectric Properties in PMN-based Relaxor Ferroelectrics (PMN계 완화형 강유전체에서의 압전물성)

  • Park, Jae-Hwan;Park, Jae-Gwan;Kim, Yun-Ho;Park, Soon-Ja
    • Korean Journal of Materials Research
    • /
    • v.9 no.3
    • /
    • pp.240-243
    • /
    • 1999
  • Piezoelectric properties of O.9PMN-0.1PT relaxor ferroe1ectrics were investigated in the temperature range of $-40^{\circ}C~$100^{\circ}C$. After poled at $-40^{\circ}C$, electro-mechanical properties of the samples were measured by resonance antiresonance method. As the resonance behavior was shown in impedance spectrum obtained below $0^{\circ}C$, it can be c conduded that 0.9PMN-0.1PT is bona-fide ferroelectrics below the phase transition temperature. It is very noteworthy that electro-mechanical resonance occurs at the temperatures far above the phase transition temperature. It is coneluded that ferroelectricity in 0.9PMN-0.1PT relaxor were verified far above the phase transition temperature.

  • PDF

Influence of Water Temperature on Egg Development of the Red Sea Bream, Pagrus major (참돔, Pagrus major의 난발생속도에 미치는 수온의 영향)

  • Yoo, Sung-Kyoo;Chang, Young-Jin;Kang, Kyoung-Ho
    • Journal of Aquaculture
    • /
    • v.4 no.1
    • /
    • pp.13-18
    • /
    • 1991
  • In order to obtain basic biological data for effective seed production of the red sea bream, Pargus major, the influence of water temperature on egg development was investigated. The time of egg development was shorter with higher water temperature. The relationships between the water temperature($T\;:\;^{\circ}C$) and the required time(t : hour) from egg to each developmental stage were given as follows : 8-cell 1/t=0.0618T-0.5877(r=0.9899) Morula : 1/t=0.0284T-0.2556(r=0.9948) Kupffer's : 1/t=0.0076T-0.0829(r=0.9902) vesicle Hatching : 1/t=0.0031T-0.0350(r=0.9985) Biological minimium temperature for the egg development was estimated to be $10.2^{\circ}C$ in average.

  • PDF

Effects of Different Dietary Cadmium Levels on Growth and Tissue Cadmium Content in Juvenile Parrotfish, Oplegnathus fasciatus

  • Okorie, Okorie E.;Bae, Jun Young;Lee, Jun-Ho;Lee, Seunghyung;Park, Gun-Hyun;Mohseni, Mahmoud;Bai, Sungchul C.
    • Asian-Australasian Journal of Animal Sciences
    • /
    • v.27 no.1
    • /
    • pp.62-68
    • /
    • 2014
  • This feeding trial was carried out to evaluate the effects of different dietary cadmium levels on growth and tissue cadmium content in juvenile parrotfish, Oplegnathus fasciatus, using cadmium chloride ($CdCl_2$) as the cadmium source. Fifteen fish averaging $5.5{\pm}0.06$ g (mean${\pm}$SD) were randomly distributed into each of twenty one rectangular fiber tanks of 30 L capacity. Each tank was then randomly assigned to one of three replicates of seven diets containing 0.30 ($C_0$), 21.0 ($C_{21}$), 40.7 ($C_{41}$), 83.5 ($C_{83}$), 162 ($C_{162}$), 1,387 ($C_{1,387}$) and 2,743 ($C_{2,743}$) mg cadmium/kg diet. At the end of sixteen weeks of feeding trial, weight gain (WG), specific growth rate (SGR) and feed efficiency (FE) of fish fed $C_{21}$ were significantly higher than those of fish fed $C_{83}$, $C_{162}$, $C_{1,387}$ and $C_{2,743}$ (p<0.05). Weight gain, SGR and FE of fish fed $C_0$, $C_{21}$ and $C_{41}$ were significantly higher than those of fish fed $C_{162}$, $C_{1,387}$ and $C_{2,743}$. Protein efficiency ratio of fish fed $C_0$, $C_{21}$ and $C_{41}$ were significantly higher than those of fish fed $C_{1,387}$ and $C_{2,743}$. Average survival of fish fed $C_0$, $C_{21}$, $C_{41}$ and $C_{162}$ were significantly higher than that of fish fed $C_{2,743}$. Tissue cadmium concentrations increased with cadmium content of diets. Cadmium accumulated the most in liver, followed by gill and then muscle. Muscle, gill and liver cadmium concentrations of fish fed $C_0$, $C_{21}$, $C_{41}$ and $C_{83}$ were significantly lower than those of fish fed $C_{162}$, $C_{1,387}$ and $C_{2,743}$. Based on the ANOVA results of growth performance and tissue cadmium concentrations the safe dietary cadmium level could be lower than 40.7 mg Cd/kg diet while the toxic level could be higher than 162 mg Cd/kg diet.

Production of Foamed Glass by Using Hydrolysis of Waste Glass(III) - Heat Treatment for Stabilization and Scale-up Test - (폐유리의 가수분해 반응에 의한 발포유리의 제조(III) - 안정화 열처리공정 및 Scale-up Test -)

  • Lee, Chul-Tae;Um, Eui-Heum
    • Applied Chemistry for Engineering
    • /
    • v.17 no.1
    • /
    • pp.73-81
    • /
    • 2006
  • Heat treatment condition for the stabilization of foamed glass block through the foaming process of the hydrolized waste glass was investigated and scale-up test for the manufacturing of foamed glass was also attempted for the actual foaming process. Proper heat treatment condition was quenching from the foaming temperature to $550{\sim}600^{\circ}C$ for stabilization, and then annealing from stabilization temperature to $200^{\circ}C$ and holding up at $200^{\circ}C$ for removal thermal stress, and then annealing to the room temperature with cooling speed of $0.3^{\circ}C/min$. Through this heat treatment conditions, foamed glass block with size of $250mm{\times}250mm{\times}90mm$ was produced successfully. The properties of this foamed glass block showed density of $0.28{\pm}0.06g/cm^3$, thermal conductivity of $0.048{\pm}0.005kcal/hm^{\circ}C$, moisture absorption of $0.5{\pm}0.09vol%$, linear expansion coefficient of $(8.6{\pm}0.2){\times}10^{-6}m/m^{\circ}C$($400^{\circ}C$), flexural strength of $15.0{\pm}0.6kg/cm^2$, and compression strength of $39.5{\pm}0.6kg/cm^2$.

A Study on Variation of Physical Properties of the PET Filament Yarn(II) (PET 필라멘트 사의 물성 편차에 관한 연구(II))

  • 김승진;박경순;유지수;서봉기;홍성대;김연숙;심승범;김소연;박미영
    • Proceedings of the Korean Fiber Society Conference
    • /
    • 2001.10a
    • /
    • pp.295-298
    • /
    • 2001
  • 합섬필라멘트사의 경우 방사 공정이후 공정에서 받는 열처리 조건은 우선 반연 공정에서 16$0^{\circ}C$~18$0^{\circ}C$ 정도의 건열처리가 주어지고, 다음 sizing 공정에서 8$0^{\circ}C$~10$0^{\circ}C$의 습열처리, 그리고 sizing 후 dry chamber에서 10$0^{\circ}C$~15$0^{\circ}C$의 열풍이 주어진다. 그리고 2-for-1 공정을 거친 후 steammer에서 7$0^{\circ}C$~9O$^{\circ}C$ 정도의 스팀 습열처리가 주어진다. (중략)

  • PDF

Determination of self-purification constants and regulation of pollutants loaded in the ecosystems (生態系에 있어서 自淨係數의 測定과 汚染負荷量의 調節 原理)

  • Chang, Nam-Kee;Kim, Jae-Young
    • The Korean Journal of Ecology
    • /
    • v.15 no.3
    • /
    • pp.287-296
    • /
    • 1992
  • To determinate self-purification constants of pollutants loaded in the ecosystems, the self- purification process was formulated, and a measurement method of the self-purification constants was derived. $C=C_0e^{-st}$ When $C_0$ is the initial pollutant amounts loaded in a ecosystem, and C is the rest pollutant amounts after the time, t, the equation of the self-purification, s, is $s=\frac{P}{C}$ When in aquatic ecosystem, $C_0$ is the initial polluant amounts loaded in water body, and Cis the rest pollutation amounts after the time, t, the self-purification constant, s, is $s=(\frac{\ln C_0-\ln C}{t}$ Self-purification constants of pine and oak forests at kwangneung in kyonggido were 0.07 and 10 respectively, of BOD in gokneung stream in kyonggido was 0.51, and of glucose and phosphate in pools on the stone in mt.jiri were 0.49 and 15.19 respectively.

  • PDF

A NOTE ON DIFFERENCE SEQUENCES

  • Park, Jin-Woo
    • The Pure and Applied Mathematics
    • /
    • v.16 no.3
    • /
    • pp.255-258
    • /
    • 2009
  • It is well known that for a sequence a = ($a_0,\;a_1$,...) the general term of the dual sequence of a is $a_n\;=\;c_0\;^n_0\;+\;c_1\;^n_1\;+\;...\;+\;c_n\;^n_n$, where c = ($c_0,...c_n$ is the dual sequence of a. In this paper, we find the general term of the sequence ($c_0,\;c_1$,... ) and give another method for finding the inverse matrix of the Pascal matrix. And we find a simple proof of the fact that if the general term of a sequence a = ($a_0,\;a_1$,... ) is a polynomial of degree p in n, then ${\Delta}^{p+1}a\;=\;0$.

  • PDF

ON SUBSPACE-SUPERCYCLIC SEMIGROUP

  • El Berrag, Mohammed;Tajmouati, Abdelaziz
    • Communications of the Korean Mathematical Society
    • /
    • v.33 no.1
    • /
    • pp.157-164
    • /
    • 2018
  • A $C_0$-semigroup ${\tau}=(T_t)_{t{\geq}0}$ on a Banach space X is called subspace-supercyclic for a subspace M, if $\mathbb{C}Orb({\tau},x){\bigcap}M=\{{\lambda}T_tx\;:\;{\lambda}{\in}\mathbb{C},\;t{\geq}0\}{\bigcap}M$ is dense in M for a vector $x{\in}M$. In this paper we characterize the notion of subspace-supercyclic $C_0$-semigroup. At the same time, we also provide a subspace-supercyclicity criterion $C_0$-semigroup and offer two equivalent conditions of this criterion.

Rietveld Structure Refinement of Biotite Using Neutron Powder Diffraction (중성자분말회절법을 이용한 흑운모의 Rietveld Structure Refinement)

  • 전철민;김신애;문희수
    • Economic and Environmental Geology
    • /
    • v.34 no.1
    • /
    • pp.1-12
    • /
    • 2001
  • The crystal structure of biotite-1M from Bancroft, Ontario, was determined by Rietveld refinement method using high-resolution neutron powder diffraction data at -26.3$^{\circ}C$, 2$0^{\circ}C$, 30$0^{\circ}C$, $600^{\circ}C$, 90$0^{\circ}C$. The crystal structure has been refined to a R sub(B) of 5.06%-11.9% and S (Goodness of fitness) of 2.97-3.94. The expansion rate of a, b, c unit cell dimensions with elevated temperature linearly increase to $600^{\circ}C$. The expansivity of the c dimension is $1.61{\times}10^{40}C^{-1}$, while $2.73{\times}10^{50}C^{-1}$ and $5.71{\times}10^{-50}C^{-1}$ for the a and b dimensions, respectively. Thus, the volume increase of the unit cell is dominated by expansion of the c axis as increasing temperature. In contrast to the trend, the expansivity of the dimensions is decreased at 90$0^{\circ}C$. It may be attributed to a change in cation size caused by dehydroxylation-oxidation of $Fe^{2+}$ to $Fe^{3+}$ in vacuum condition at such high temperature. The position of H-proton was determined by the refinement of diffraction pattern at low temperature (-2.63$^{\circ}C$). The position is 0.9103${\AA}$ from the O sub(4) location and located at atomic coordinates (x/a=0.138, y/b=0.5, z/c=0.305) with the OH vector almost normal to plane (001). According to the increase of the temperature, $\alpha$* (tetrahedral rotation angle), $t_{oct}$ (octahedral sheet thickness), mean distance increase except 90$0^{\circ}C$ data. But the trend is less clearly relative to unit cell dimension expansion because the expansion is dominant to the interlayer. Also, ${\Psi}$ (octahedral flattening angle) shows no trends as increasing temperature and it may be because the octahedron (M1, M2) is substituted by Mg and Fe.

  • PDF

Systematic Study on the Fishes of the Family Cobitidae(Pisces, Cypriniformes). 2. Taxonomic Study on the Cobitis taenia complex from Korea (기름종개과(family Cobitidae)어류의 계통분류에 관한 연구 2. 한국산 Cobitis taenia complex의 분류학적 고찰)

  • 양서영;이혜영;양홍준;전상린;박병상;김재흡
    • Animal Systematics, Evolution and Diversity
    • /
    • v.9 no.2
    • /
    • pp.151-170
    • /
    • 1993
  • Morphometric, band-pattern and electrophoretic analysis on Cobitis taenia complex were performed to investigate the morphological and genetic differentiation and to clarify their taxonomic status. Intermediate types of band-pattern (C and D type) were more frequently expressed than that of types of C. t. taenia(type A) and C. t. lutheri (type B). Sexual dimorphism of band-pattern was observed not only in C. t. taenia(type A) and C. t. lutheri(type B). Sexual dimorphism of band-pattern was observed not only in C. t. lutheri but also in C. t. taenia and C. t. striata as well. Discriminant function analysis based on 19 morphological characters shows no significant differences among C. taenia complex. The degree of genic variation of C. t. striata was higher ( =1.48, P=31.2%, HD=0.009) than those of C. t. striata was higher( =1.48, P=31.2%, HD=0.082 and HG=0.009) than those of C. t. lutheri ( =1.37, P=2.7%, HD=0.058 and HG=0.065). The average genetic similarities between C. t. lutheri and C. t. taenia-C. t. striata were S=0.62 and S=0.66 respectively and these values indicate that C. t. tanenia has evolved specific level of differentiation. C. t. striata and C. t. lutheri show subspecifc level of close genetic similarity (S=0.82). Based on the divergent time estimate (Nei, 1975) it is assumed that C. t. tanenia was branched off from the other subspecies about two million years before present (MYBP) and C. t. striata and C. t. lutheri were differentiated about 0.6 MYBP. The use of C. sinesis an the scientific name for the Korean C. t. taenia, proposed by Kim and Lee (1988) seems incorrect since they are quite different in the structure of lamina circularis (Vladycov, 1935), the external morphology and distribution (Cheng and Zheng, 1987) and the chromosome number(Yu et al., 1989). Kim and Lee(1988) also argued that C.t. striata and C. t. lutheri should be treated as distinct species but the present study and other reports (Kim and Lee, 1984; Kim and Yang, 1993) do not support it. We conclude that C. t. taenia is a good species and C. t. striata and C. t. lutheri are subspecific status. Their scientific names should be revised in the future.

  • PDF