• Title/Summary/Keyword: growth phases

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Liquid-Phase Sintering of $YBa_2Cu_3O_x$ Ceramic Superconductor and Grain Size Control Using $Y_2BaCuO_5$ ($YBa_2Cu_3O_x$초전도체의 액상 소결과 $Y_2BaCuO_5$를 이용한 입자 크기 제어)

  • 노광수;이정용;위당문
    • Journal of the Korean Ceramic Society
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    • v.27 no.3
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    • pp.423-429
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    • 1990
  • YBa2Cu3Ox ceramics superconductors fabricated using solid state reaction usually contain second phases, such as BaCuO2 and CuO. These second phases are located long the grain boundaries and enhance the abnormal growth of YBa2Cu3Ox grains and, consequently, generate the microcracks. These second phaases were reduced by adding Y2BaCuO5 into solid state reacted YBa2Cu3Ox ceramics. Y2BaCuO5 reacts with grain boundary second phases and reduces the grian size of the ceramics. It was observed the critical current density was improved by adding Y2BaCuO5 into solid state reacted YBa2Cu3Ox ceramic superconductor.

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The Microbiological Quality Assessment of Chicken Soup Utilizing HACCP Model in a University Foodservice Establishment (대학 급식 시설의 닭곰탕 생산과정에서 HACCP Model 을 사용한 미생물적 품질 평가에 관한 연구)

  • Kwak, Tong-Kyung;Rew, Kyung
    • Korean journal of food and cookery science
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    • v.2 no.2
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    • pp.76-83
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    • 1986
  • Time and temperature, pH and Aw, and microbiological evaluation were made to identify critical control points during various phases in product flow of chicken soup preparation in a university foodservice establishment. The results are summarised as follows: 1) Time and temperature data indicated that the phases of cooling after cooking, post-preparation, and holding ingredients at room temperature before assembly were critical. 2) pH and Aw values were in favorable for microbial growth. 3) Microbiological data indicated that the phases of basic ingredients. post-preparation and holding ingredients before assembly were critical. 4) Critical control points identified were; basic ingredients, cooling after cooking, post-preparation, holding before assembly and service, and assembly and service. 5) Several guidelines were suggested for the effective qualitly control program.

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Investigation of γ/γ' Growth by Macro Segregation in the Ni-Base Single Crystal Superalloy, CMSX-10 (CMSX-10 단결정 초내열합금에서 거시편석에 따른 γ/γ' 응고조직 형성)

  • Yoon, Hyeyoung;Sung, Changhoon;Shin, Jongho;Han, Seong Zeon;Lee, Jehyun
    • Korean Journal of Materials Research
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    • v.25 no.9
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    • pp.435-441
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    • 2015
  • The ${\gamma}/{\gamma}^{\prime}$ two-phases, commonly known as a eutectic structure, are observed in the ${\gamma}$ interdendritic region of a Ni-base superalloy. However, the growth behavior of the ${\gamma}/{\gamma}^{\prime}$ two-phases, whether it is of eutectic or peritectic nature, has not been decidedly established. Directional solidifications were, thus, performed with the planar interface at a low growth rate of $0.5{\mu}m/s$ in order to promote macro segregation. Directional solidification started with the ${\gamma}$ planar interface and the ${\gamma}^{\prime}$ phase nucleated on the ${\gamma}$ planar interface at the solidification fraction of 0.75. The ${\gamma}/{\gamma}^{\prime}$ two-phases showed the ${\gamma}^{\prime}$ rod structure as major phase and the ${\gamma}$ minor phase between ${\gamma}^{\prime}$ rods, and the volume fraction of the ${\gamma}$ phase changed continuously with an increasing solidification fraction. The two-phase ${\gamma}/{\gamma}^{\prime}$ is seen as the coupled peritectic.

Characteristics and Model for Growth of Rhizopus oryzae on the Simulated Gas-solid Interface

  • Jia, Shiru;Kong, Rixiang;Dong, Huijun;Kwun, Kyu-Hyuk;Kim, Sun-Il;Cho, Ki-An;Choi, Du Bok
    • Korean Journal of Environmental Biology
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    • v.22 no.4
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    • pp.494-500
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    • 2004
  • In order to investigate the effect on morphology of Rhizopus oryzae and production of lactic acid, various interface materials were used. Morphology of fungal showed sheet and flock when resin was added. The production of lactic acid was increased dramatically when interface materials were added. Furthermore, the effect of resin was more significant than that of others. It was assumed that interface materials could absorb substrate and microorganism together, so microorganism was not inhibited by substrate. The effect of static electric field on the interface culture was studied. When the exerting potential was 6.78 voltage, the biomass y was obviously higher than that of zero voltage. A simulated gas-solid interface system was developed to study the growth and two phases model for the growth of Rhizopus oryzae was build up that depended on the symmetric branching theory. An important parameter F was researched. The results indicated that the value of F had obvious difference at exponential and deceleration period, respectively.

Effect of the grain boundary on the magnetic properties of the multi-seeded melt growth processed YBCO superconductors (다중종자결정성장법으로 제조한 YBCO 초전도체의 결정입계에 따른 자기적 성질의 영향)

  • Kim, Chan-Joong;Joo, Jin-Ho;Han, Young-Hee;Han, Sang-Chul;Sung, Tae-Hyun;Hong, Gye-Won;Kim, Ho-Jin
    • 한국초전도학회:학술대회논문집
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    • v.10
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    • pp.293-297
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    • 2000
  • Multiseeding with (100)/(100) grain junctions of top-seeded melt growth (TSMG) processed YBCO superconductors was studied. The effect of the number of seeds and the distance between two seeds on the levitation forces and the trapped magnetic fields of the TSMG-processed YBCO samples was investigated. Multiple seeding shortened the processing time for the fabrication of TSMC-processed YBCO superconductors. The large magnetic field was trapped at the grain junction when two seeds was placed without spacing, while the amount of the magnetic field decreased when the seed distance increased. This is attributed to the increased amount of the residual melt phases around the grain junctions.

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Effects of Sr Additions on the Interfacial Reaction Layers Formed between Liquid Al-Si-Cu Alloy and Cast Iron

  • Kyoung-Min Min;Je-Sik Shin;Jeong-Min Kim
    • Korean Journal of Materials Research
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    • v.33 no.9
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    • pp.353-359
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    • 2023
  • This study investigated the growth behavior and characteristics of compounds formed at the interface between a liquid Al-Si-Cu alloy and solid cast iron. Through microstructural analyses, it was observed that various AlFe and AlFeSi phases are formed at the interface, and the relative proportion of each phase changes when small amounts of strontium are added to the Al alloy. The results of the microstructural analysis indicate that the primary phases of the interfacial compounds in the Al-Si-Cu base alloy are Al8Fe2Si and Al4.5FeSi. However, in the Sr-added alloys, significant amounts of binary AlFe intermetallic compounds such as Al5Fe2 and Al13Fe4 formed, in addition to the AlFeSi phases. The inclusion of Sr has a slight diminishing effect on the rate at which the interfacial compounds layer thickens during the time the liquid Al alloy is in contact with the cast iron. The study also discusses the nano-indentation hardness and micro-hardness of the interfacial phases.

Relationship between some Phenological Parameters and Somatic Embryogenesis in Theobroma cacao L.

  • Issali, Auguste Emmanuel;Traore, Abdoulaye;Ngoran, Jeanne Andi Kohi;Koffi, Edmond Kouablan;Sangare, Abdourahamane
    • Journal of Crop Science and Biotechnology
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    • v.11 no.1
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    • pp.23-30
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    • 2008
  • The relationship between three phenological parameters and somatic embryogenesis was investigated during a two-year period. Staminodes and petals from six hybrids and two clones as controls were sowed on three distinct primary callus growth media. Flowering level, fructification level, and leaf thrusts rhythm as phenological parameters were measured simultaneously during the weekly harvest of flower buds. Mean and coefficient of variation of the measured parameters highlighted stable phenological phases. The relationship between phenological parameters and somatic embryogenesis was investigated first by comparing the variation of somatic embryogenesis and that of the phenological parameters, and second by using Pearson's linear correlation. Except for the fructification level in both control clones the first year, the other parameters recorded stable phenological phases, regardless of the genotype and year. Favorable and unfavorable phases for the somatic embryogenesis were identified. In hybrids, favorable phases included February, August, September, and October. In both control clones, time interval propitious to embryogenesis stretched from February to December. The significance of the coefficient of correlation seemed to establish a relationship between somatic embryogenesis and phenology. However, a causal link could not be established. Leaf thrusts rhythm was revealed to be the phenological parameter most linked to somatic embryogenesis. Attempts to optimize embryogenesis during unfavorable phases, showed that a correction of 2.4 D/TDZ concentration is not the solution.

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Leuconostoc mesenteroides CJNU 0147 and Lactobacillus casei CJNU 0588 Improve Growth of a Bifidobacterium lactis Strain in Co-cultures

  • Eom, Ji-Eun;Moon, Gi-Seong
    • Preventive Nutrition and Food Science
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    • v.16 no.4
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    • pp.386-389
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    • 2011
  • Previous studies have confirmed that fermented whey produced by Leuconostoc mesenteroides CJNU 0147 or Lactobacillus casei CJNU 0588 display bifidogenic growth stimulator (BGS) activity. The present study sought to determine if the strain itself can improve the growth of bifidobacteria in co-cultures. In reinforced clostridial medium (RCM), both strains stimulated the growth of a Bifidobacterium lactis strain during the exponential phase and also stimulated the growth during almost all growth phases in whey broth. Fermented whey containing viable Leu. mesenteroides CJNU 0147 and L. casei CJNU 0588 cells maintained viability of the B. lactis strain stored at $10^{\circ}C$ in MRS broth. Viable cell count of the B. lactis strain without the fermented whey was decreased to 5.6 log cfu/mL after 15 days, whereas that of the strain with the fermented whey was slightly increased to 7.1 log cfu/mL as compared with initial viable cell count of 6.9 log cfu/mL.

Growth promotion effect of red ginseng dietary fiber to probiotics and transcriptome analysis of Lactiplantibacillus plantarum

  • Hye-Young Yu;Dong-Bin Rhim;Sang-Kyu Kim;O-Hyun Ban;Sang-Ki Oh;Jiho Seo;Soon-Ki Hong
    • Journal of Ginseng Research
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    • v.47 no.1
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    • pp.159-165
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    • 2023
  • Background: Red ginseng marc, the residue of red ginseng left after water extraction, is rich in dietary fiber. Dietary fiber derived from fruits or vegetables can promote the proliferation of probiotics, and it is a key technology in the food industry to increase the productivity of probiotics by adding growth-enhancing substances such as dietary fiber. In this study, the effect of red ginseng dietary fiber (RGDF) on the growth of probiotic bacterial strains was investigated at the phenotypic and genetic levels. Methods: We performed transcriptome profiling of Lactiplantibacillus plantarum IDCC3501 in two phases of culture (logarithmic (L)-phase and stationary (S)-phase) in two culture conditions (with or without RGDF) using RNA-seq. Differentially expressed genes (DEGs) were identified and classified according to Gene Ontology terms. Results: The growth of L.plantarum IDCC3501 was enhanced in medium supplemented with RGDF up to 2%. As a result of DEG analysis, 29 genes were upregulated and 30 were downregulated in the RGDF-treated group in the L-phase. In the S-phase, 57 genes were upregulated and 126 were downregulated in the RGDF-treated group. Among the upregulated genes, 5 were upregulated only in the L-phase, 10 were upregulated only in the S-phase, and 3 were upregulated in both the L- and S-phases. Conclusions: Transcriptome analysis could be a valuable tool for elucidating the molecular mechanisms by which RGDF promotes the proliferation of L.plantarum IDCC3501. This growth-promoting effect of RGDF is important, since RGDF could be used as a prebiotic source without additional chemical or enzymatic processing.

Economic Growth, Crisis, and Recovery in Cameroon: A Literature Review

  • Tambi, Mbu Daniel
    • The Journal of Industrial Distribution & Business
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    • v.6 no.1
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    • pp.5-15
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    • 2015
  • Purpose - This study reviews Cameroon's economic growth, crisis, and recovery, aiming to: review the principal factors of Cameroon's real economic growth; explore the causes of its economic crisis analyze the determinants of its economic recovery; and suggest appropriate policies to ameliorate economic growth. Research design, data, and methodology - By reviewing the relevant literature and economic indicators, we observed that from the 1980s to the present, Cameroon experienced all the possible business cycle phases: economic prosperity (until 1985), economic and social crisis (1986-1994), and renewed economic growth (after 1995). Results - As a result of the economic changes in Cameroon, its macroeconomic indicators have evolved. Poverty and inequality have changed in both quantitative and qualitative terms. Throughout the examined period, rural poverty has become more widespread, deeper, and more severe than urban poverty, while inequality has experienced greater increases in urban areas relative to rural zones. Conclusions -To reap maximum benefits and reduce poverty from these economic changes, Cameroon needs to liberalize trade and foreign exchange transactions to attract foreign investment, especially during the current globalization.