• Title/Summary/Keyword: $C_0$

Search Result 59,618, Processing Time 0.074 seconds

Fabrication and characteristics of modified PZT System doped With $La_2O_3$ ($La_2O_3$가 첨가된 modified PZT계의 제조 및 특성)

  • 황학인;박준식;오근호
    • Journal of the Korean Crystal Growth and Crystal Technology
    • /
    • v.7 no.3
    • /
    • pp.418-427
    • /
    • 1997
  • The effect of $La_2O_3$ as a dopant on the microstructure structure, crystal structure and electrical properties was studied. $0.05Pb(Sn_{0.5}Sb_{0.5})O_3+0.11PbTiO_3+0.84PbZroO_3+0.4Wt%MnO_2$ (=0.05PSS +0.11PT+0.84PZ+0.4wt%$MnO_2$) systems doped with 0, 0.1, 0.3, 0.5, 0.7, 1, 3, 5 mole% $La_2O_3$ were fabricated and investigated sintering density, crystal structure and micro-structure. The sintered 0.05PSS+0.11PT+0.84PZ+0.4wt%$MnO_2$ system doped with $La_2O_3$showed sintering density of the range of 7.683 g/㎤ of 0 mole% doping to 7.815 g/㎤ of 0 mole% doping. The average grain sizes in the range of 0 to 5 mole% $La_2O_3$were decreased from 9.0 $\mu\textrm{m}$ to 1.3 $\mu\textrm{m}$. X-ray diffraction investigation of sintered bodies showed that solid solutions were formed between 0.05PSS+0.11PT+0.84PZ+0.4wt%$MnO_2$ system and $La_2O_3$ in the range of 0 to 1 mole% but second phases were formed in case of 3, 5 mole%. Dielectric constants at 1 kHz were increased with 0 to 3 mlole% $La_2O_3$ before and after poling at the condition of 5 $KV_{DC}$/mm at $120^{\circ}C$ or $140^{\circ}C$ during 20 minutes. All Dielectric losses at 1 kHz were less than 1%, Curie temperatures were $208^{\circ}C$, $183^{\circ}C$, $152^{\circ}C$ and $127^{\circ}C$ at 0, 0.5, 1, 3 mole% $La_2O_3$ respectively. The values of $K_p$ were increased from 0 to 3 mole% $La_2O_3$ after poling at condition of 5 $KV_{DC}$mm at the condition of $120^{\circ}C$ or $140^{\circ}C$. The case of 0.7 mole% $La_2O_3$doped 0.05PSS+0.11PT+0.84PZ+0.4wt%$MnO_2$ system showed $K_p$ of 14.5% by poling at $140^{\circ}C$ during 20 minutes.

  • PDF

Production and Some Properties of Chitinolytic Enzymes by Antagonistic Bacteria (길항세균들이 생산하는 Chitin 분해효소의 특성)

  • 박서기;이효연;허정원
    • Korean Journal Plant Pathology
    • /
    • v.11 no.3
    • /
    • pp.258-264
    • /
    • 1995
  • Production and some properties of chitinolytic enzymes were investigated by 80% ammonium sulfate precipitates (crude enzymes) from culture supernatant of antagonistic bacteria, Chromobacterium violaceum strain C-61 and strain C-72, Aeromonas hydrophila, Aeromonas caviae, and Serratia marcescens. The maximum production of chitinase was obtained from the 3-day culture at 28$^{\circ}C$ in C. violaceum stains, the 6-day culture in S. marcescens, and the 2-day culture in A. hydrophila and A. caviae. In the optimum culture periods, chitinase activity of C. violaceum strains C-61 was 1.5, 5.5, 12.0 and 11.3 times higher than those of strain C-72, S. marcescens, A. hydrophila and A. caviae, respectively. However, N,N'-diacetylchitobiase activity was 3.2 times higher in S. marcescens than in C. violaceum strain C-61, and that of Aeromonas spp.was very low. On gels containing glycol chitin, chitinase of C. violaceum strains showed four isoforms of 54-, 52-, 50- and 37-kDa, whereas there were four isoforms of 58-, 52-, 48- and 38-kDa in S. arcescens, three isoforms of 70-, 58- and 54-kDa in A. hydrophila and six isoforms of 90-, 79-, 71-, 63-, 58- and 38-kDa in A. caviae. The chitinase of C. violaceum strain C-61 was most active at pH 7.0 and at 5$0^{\circ}C$ and was stable in ranges of pH 5.0~10.0 for 2 hours and of 0~5$0^{\circ}C$ for 30 min.

  • PDF

Freshness Extension of Ginseng with Freezing Point Depressing Agents (빙점강하제를 이용한 수삼의 선도연장)

  • 남궁배;정문철;김동만;문광덕;최종욱
    • Food Science and Preservation
    • /
    • v.7 no.1
    • /
    • pp.57-62
    • /
    • 2000
  • Ginseng was stored at a temperature lower than the freezing point after a treatment of freezing point depressing agents to extend its freshness. Respiration rate at freezing point of ginseng, -1.7${\pm}$0.1$^{\circ}C$, was inhibited 92% and 97% compared with those stored at 5$^{\circ}C$or 20$^{\circ}C$ , respectively. Sorbitol solution chosen as a freezing point depressing agent lowered the freezing point of ginseng to about -3.0$^{\circ}C$. Ginsengs treated with the sorbitol solution and packaged with 0.06mm LDPE was stored at -2$^{\circ}C$ , and the quality change was then compared with ginsengs stored at 0$^{\circ}C$ and 5$^{\circ}C$. Weight loss of ginsengs stored at -2$^{\circ}C$ for 100days was 1.5%, which is about 2.6times less than those stored at 5$^{\circ}C$. However, there were no significant difference between the ginsengs stored at -2$^{\circ}C$ and at 0$^{\circ}C$(1.9%). Spoilage rate of the ginsengs was 100% after 50 days of storage at 5$^{\circ}C$ and 25% after 100days at 0$^{\circ}C$respectively. but that of ginsengs stored at -2$^{\circ}C$ was 13%, which was half than that of ginsengs stored at 0$^{\circ}C$. Firmness and amount of monoscaccharides in ginsengs were decreased during storage at 5 or 0$^{\circ}C$ but ginsengs stored at -2$^{\circ}C$ showed better firmness and an increase in monosaccharides such as fructose and glucose. From above, when ginseng treated with freezing pont depressing agents were stored at -2$^{\circ}C$, the shelf life was extended to 2 or 3 times longer than those that were stored at 5 or 0$^{\circ}C$, respectively.

  • PDF

A Study on Dyeing of Silk with Different Reactive Dyes (반응성염료의 반응기에 따른 견섬유염색에 관한 연구)

  • 정지인;류효선
    • Textile Coloration and Finishing
    • /
    • v.4 no.4
    • /
    • pp.73-80
    • /
    • 1992
  • The influence of four types of reactive dyes that are different in reactive group on silk fabric were investigated at three different temperatures, 5$0^{\circ}C$, 7$0^{\circ}C$, 9$0^{\circ}C$ and the pH range from 7.0 to 11.0. The amount of absorption and fixation showed the optimum condition. The damage of silk during dyeing was determined by the change of physical properties. The results are given as follows: 1. The amount of dye fixed on fabrics at constant pH varied upon the reactivity of dyes. The affinity of dyes for silk fabrics were in order of Lanasol>Procion>Remazol>Cibacron. 2. The percentage of dye fixation on fabrics showed different tendency with temperature. The dye fixation of Cibacron and Procion was decreased above 7$0^{\circ}C$ because of the influence of hydrolysis. The dye fixation of Lanasol and Remazol was increased with the increase of temperature. This showed that temperature did not affect on hydrolysis. 3. The tensile strength of dyed fabric decreased with increasing pH and temperature owing to high temperature and alkaline damage on silk fabric. 4. The optimum conditions of dyeing silk with reactive dyes were as follows: Cibacron -7$0^{\circ}C$, pH 9.0, Procion-5$0^{\circ}C$, pH 7.0, Remazol-5$0^{\circ}C$, pH 8.0, and Lanasol-9$0^{\circ}C$, pH 9.0.

  • PDF

Effects of Temperature on Reproduction and Development of Firefly, Luciola lateralis(Coleoptera: Lampyridae) (온가가 애반딧불이의 생식과 발육에 미치는 영향)

  • 이기열;안기수;강효중;박성규;김종길
    • Korean journal of applied entomology
    • /
    • v.42 no.3
    • /
    • pp.217-223
    • /
    • 2003
  • Effects of temperature on the development and reproduction of the Luciola lateralis were investigated at various temperatures. The development time of eggs, larvae, and pupae were shorter at higher temperatures than at lower ones. The insect did not develop at 10$^{\circ}C$ and 35$^{\circ}C$. The hatchability was 61.5% at 15$^{\circ}C$, 73.9% at 20$^{\circ}C$, 93.3% at 23$^{\circ}C$, 91.8% at 25$^{\circ}C$, 74.0% at 27$^{\circ}C$, and 46.0% at 30$^{\circ}C$, indicating the best hatchability rate at the temperature condition of 23 DC. Larval periods were 341.5:t 23.2 days at 15$^{\circ}C$, 265.5${\pm}$17.5 days at 20$^{\circ}C$, and 250.9${\pm}$11.7 days at 25$^{\circ}C$. Pupal periods were 94.7${\pm}$11.5 days at 15$^{\circ}C$, 41.7${\pm}$9.1 days at 20$^{\circ}C$, and 18.5${\pm}$7A days at 25$^{\circ}C$. Emergence rate was 23.3, 89.3 and 80.7%, respectively at the above temperatures. Adult longevity of female was 18.0 days at 15$^{\circ}C$, 2004 days at 20$^{\circ}C$, 10.7 days at 25$^{\circ}C$, and 5.8 days at 30$^{\circ}C$. Mean fecundity per female was higher at 20$^{\circ}C$ compared with at other temperatures. The developmental zero point temperatures (1) and the total effect temperatures (I<) of egg, larva, pupa, and complete development were 10.6, 14.0, and l3.1$^{\circ}C$ and 214.8, 1,564.8, and 229.2 degree-days, respectively. Mean generation time in days (T) was shorter at higher temperature. Net reproductive rate per generation (Ra) was the lowest at the highest temperature as well as at the lowest, and it was 177.19 which was the highest at 23$^{\circ}C$. The intrinsic rate of natural increase (r$\sub$m/) was highest at 27$^{\circ}C$ as 0.019. As a result, optimum range of temperature for L. lateralis growth was between 20-25$^{\circ}C$.

A Comparison Study on the Skin Temperature on the Adult Male. Female at Environmental Temperature (각 환경기온하에서의 성인 남 . 여자의 피부온 비교)

  • 심부자
    • Proceedings of the ESK Conference
    • /
    • 1997.04a
    • /
    • pp.227-246
    • /
    • 1997
  • With a view of to providing basic data for designing male's and female's clothes, heslthy males and females(five each) were exposed to three different environmental temperature( $20{\pm}1.0^{\circ}C$ $28{\pm}1.0^{\circ}C$,$32{\pm}1.0^{\circ}C$ in the nude. Their adaptation of skin temperature, physilogical responses, oral temperature, blood pressure, pulse rates) and psychological reactions (thermal, comfort and perceptive sweat sensations) were analyzed to be as follows; The subjects's skin temperature had a similar look of adaptation, but the stability of skin temperature differed at the $20{\pm}1.0^{\circ}C$and at the $28{\pm}1.0^{\circ}C$ Males had higher skin temperatures at three environmental temperatures, but females showed a higher temperature change at the $20{\pm}1.0^{\circ}C$ and$28{\pm}1.0^{\circ}C$ and males at the $32{\pm}1.0^{\circ}C$ Thus females were more resistant to the cold, while male were more resistant to the heat. As environmental temperature increased, oral temperature and pulse rates also grew up. Females turned higher in oral temperature and lower in blood pressure, but both sexes had a normal range of physiological reactions. Even though three environmental temperature were same changes in thermal sensation at and in perceptive sweat sensation at $28{\pm}1.0^{\circ}C$and in perceptive sweat sensation at$32{\pm}1.0^{\circ}C$ the two sexes had the same response in comfort sensation at the three environmental temperature.

  • PDF

Larval Survival Rate and Growth of Pandalus gracilis Using Two Temperature Conditions Reared in the Laboratory (한국산 남방도화새우, Pandalus gracilis유생의 두 온도 구간에서의 생존율과 성장)

  • 최정화;마채우
    • Journal of Aquaculture
    • /
    • v.17 no.1
    • /
    • pp.58-61
    • /
    • 2004
  • Larvae of Pandalus gracilis were reared in the laboratory under controlled conditions (salinity, 32.5∼34.5; photo-periods, 12L: 12D). The experiments were designed to examine effects of temperature (10 and 2$0^{\circ}C$) on larval development, survival, intermolt period and larval growth. The higher survival rate was obtained at 2$0^{\circ}C$ than at 1$0^{\circ}C$ and larvae reached later stages at 2$0^{\circ}C$. Intermolt period increased significantly with increasing of instar number and was longer at 1$0^{\circ}C$ than at 2$0^{\circ}C$.

A comparision study on the variation of skin temperature on the adult male. female at environmental temperature (각 환경기온하에서의 성인 남녀의 피부온 비교)

  • 심부자
    • Journal of the Ergonomics Society of Korea
    • /
    • v.16 no.2
    • /
    • pp.39-59
    • /
    • 1997
  • With a view to providing basic data for designing male's and female's clothes, healthy males and females(five each) were exposed to three different environmental temperature($20{\pm}1.0^{\circ}C$, $28{\pm}1.0^{\circ}C$, $32{\pm}1.0^{\circ}C$) in the nude. Their adaptation of skin temperature, physiological responses( rectal temperature, blood pressure, pulse rates) and psychological reactions(thermal, comfort and perceptive sweaty sensations) were analyzed as follows; The subjects's skin temperature had a similar look of adaptation, but the stability of skin temperature differed at tha $20{\pm}1.0^{\circ}C$ and at the $28{\pm}1.0^{\circ}C$ Males had higher skin temperature at three environmental temperatures, but females showed a higher temperature change at the $20{\pm}1.0^{\circ}C$ and $28{\pm}1.0^{\circ}C$ and males at the$32{\pm}1.0^{\circ}C$ Thus females were more resistant to the cold, while males were more resistant to the heat. As environmental temperature increased, rectal temperature and pulse rates also grew up. Females turned higher in rectal temperature and lower in blood pressure, but both sexes had a normal range of physiological reactions. Even though three environmental temperatures were same changes in thermal sensation at $28{\pm}1.0^{\circ}C$and in perceptive sweat sensation at $32{\pm}1.0^{\circ}C$, two sexes had the same response in comfort sensation at the three environmental temperatures.

  • PDF

Effects of Diet and Time on Feed on Fatty Acid Composition in Muscle of Charolais Steers (사료급원과 급여기간이 Charolais 거세우 근내 지방산 조성에 미치는 영향)

  • 최낙진;강수원;권응기;조원모;전병수;박병기
    • Journal of Animal Science and Technology
    • /
    • v.48 no.6
    • /
    • pp.847-860
    • /
    • 2006
  • This study investigated the effects of feeding Charolais steers on diets rich in either n-6 or n-3 polyunsaturated fatty acids (PUFA) and time on feed (TOF) on muscle fatty acid composition and content. Twenty eight steers were fed on ad libitum forage and one of two concentrates varying in the source of fat; soya (high in C18:2 n-6) or whole linseed (high in C18:3 n-3) for either 60 or 90 days in IGER (Institute of Grassland and Environmental Research, UK). The concentrates were fed at approximately 0.73 of total DM intake. TOF influenced carcass weight, conformation and fatness scores, which were higher at 90 v. 60 days (P<0.05). Diet did not affect total fatty acid content of neutral lipid in m. longissimus thoracis but feeding linseed increased total phospholipid fatty acid by approx- imately 15%(P<0.05). Linseed increased the amount and proportion of C18:3 n-3 (P<0.001) and the proportion of CLA (cis-9, trans-11 conjugated linoleic acid), while soya increased the content (P<0.05) and proportion (P<0.001) of C18:2 n-6 in muscle neutral lipid. In muscle phospholipid, linseed significantly increased the amount of CLA, C18:3 n-3 and its longer chain derivatives as well as C14:0, C16:0, C18:0. C18:1 trans and C18:2 n-6. The amount and proportion of C18:2 n-6 and its longer chain C20 derivatives were higher on feeding soya. TOF (90 v. 60 day) increased the content of C14:0, C16:0, C16:1, CLA, C18:1 n-9, C18:2 n-6 and C18:3 n-3 in muscle neutral lipid. The P:S was not affected by diet or TOF. The ratio of C18:2 n-6 : C18:3 n-3 and sum of n-6 : n-3 fatty acids were higher in muscle from animals fed on linseed v. soya (P<0.001). The study indicates that the PUFA composition of beef muscle may be significantly modified by feeding contrasting dietary lipids, soya vs. linseed. Feeding linseed produced a better balance of muscle fatty acids, more in line with current nutritional recommendations with a lower C18:2 n-6:C18:3 n-3 ratio associated with higher muscle content of C18:3 n-3 and C20:5 n-3 and CLA and lower C20:4 n-6.

Sintering of Silicon Carbide by Reaction Bonding and its Characteristics (Effect of Addition of B4C and Y2O3 in Initial Sintering Precess) (반응소결에 의한 SiC의 소결과 그 특성에 관한 연구 (초기 소결과정에서의 B4C 및 Y2O3의 첨가 영향))

  • 백용혁
    • Journal of the Korean Ceramic Society
    • /
    • v.25 no.6
    • /
    • pp.609-614
    • /
    • 1988
  • This study was carried out to investigate the effects of B4C or Y2O3 additives on the tendency of sintering, $\beta$-SiC synthesis and mineral phase changes by reaction bonding of SiC at 145$0^{\circ}C$. At the sintering temperature of 145$0^{\circ}C$, the additives such as B4C or Y2O3 did not improved porosity and bending strength. Added more than 1.5% of Y2O3, 0.5-0.3% of B4C, the formation of $\beta$-SiC was increased. At higher temperature above 145$0^{\circ}C$, it seems that the bodies added B4C, contained 3C form of SiC were denser than that of Y2O3 added. Because the transition of 3Clongrightarrow4Hlongrightarrow6H promoted sintering.

  • PDF