• Title/Summary/Keyword: Initial growth

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A Study on the Apparent Negative Crack Growth Phenomenon of J-R Curve(II) (J-R 곡선에서의 균열길이 감소현상에 관한 연구 (II))

  • 석창성;최용식
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.16 no.9
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    • pp.1627-1631
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    • 1992
  • It often occurs in J-R testing that some initial crack extension (.DELTA.a) data points have anomalous negative values. The reason for the apparent negative crack growth is due to the analysis method. The phenomenon as a possible source of error in determining $J_{IC}$ or J-R curve from partial unloading compliance experiments may be eliminated by the compliance correction equation or the offset technique. In this study, the correction methods are suggested and examined by the measurement of the actual crack length and $J_{JC}$ analysis.

Antimicrobial Effect of Monascus Strains Isolated from Ang-Khak (홍국으로부터 불리한 Monascus 균주의 향균효과)

  • 류춘선;김영배;황한준
    • Journal of Food Hygiene and Safety
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    • v.10 no.4
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    • pp.271-277
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    • 1995
  • Total 29 Monascus strains were isolated from Ang-Khak and 4 of them were selecte based on the relative intensity of soluble red pigment and growth rate. The optimum growth temperature of the selected isolates was 32.5$^{\circ}C$ on malt extract agar(MEZ) plate. The optimum growth pH was 5.0 on czapek yeast extract agar plate, while it was pH 6.2 or 6.5 on MEA plate. Isolate No. 116, especially, showed the strongest animicrobial activity aganist Bacillus subtilis and Staphylococcus aureus but much less aganist Escherichia coli and Enterobacter aerogenes. The maximun antimicrobial activity of isolate No. 116 against St. aureus was achieved at initial pH 5.3 on rice extract broth. The acitivity was increased with increasing amount of culture broth concentrate of isolate No. 116.

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Nucleation, Growth and Properties of $sp^3$ Carbon Films Prepared by Direct $C^-$ Ion Beam Deposition

  • Kim, Seong I.
    • The Korean Journal of Ceramics
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    • v.3 no.3
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    • pp.173-176
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    • 1997
  • Direct metal ion beam deposition is considered to be a whole new thin film deposition technique. Unlike other conventional thin film deposition processes, the individual deposition particles carry its own ion beam energies which are directly coupled for the formation of this films. Due to the nature of ion beams, the energies can be controlled precisely and eventually can be tuned for optimizing the process. SKION's negative C- ion beam source is used to investigate the initial nucleation mechanism and growth. Strong C- ion beam energy dependence has been observed. Complete phase control of sp3 and sp3, control of the C/SiC/Si interface layer, control of crystalline and amorphous mode growth, and optimization of the physical properties for corresponding applications can be achieved.

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A Prediction of Crack Growth Path by Boundary Element Method (경계요소법(境界要素法)에 의한 균열 진전경로(進展經路)의 예측)

  • S.C.,Kim;W.K.,Lim
    • Bulletin of the Society of Naval Architects of Korea
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    • v.25 no.4
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    • pp.39-46
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    • 1988
  • The purpose of this paper is to apply the boundary element method to predict the crack growth path. The quarter point element with traction singularity at the crack tip is applied to compact tension type specimens and two inclined slit problems under compression load. The maximum stress criterion which was originally derived for the crack initiation is extended to the analysis of the crack propagation. The predicted crack paths with 1/4 crack growth increment of initial crack length agree quite well with experimental results. It is found that the computed crack path of the boundary element analysis is not mainly affected by the crack increment length.

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Carbon Dioxide Mitigation by Microalgal Photosynthesis

  • Lee Jeong, Mi-Jeong;Gillis, James M.;Hwang, Jiann-Yang
    • Bulletin of the Korean Chemical Society
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    • v.24 no.12
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    • pp.1763-1766
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    • 2003
  • Algal growth studies of Chlorella strains were conducted in a batch mode with bench type experiments. Carbon dioxide fixation rates of the following green microalgae were determined: Chlorella sp. H84, Chlorella sp. A2, Chlorella sorokiniana UTEX 1230, Chlorella vulgaris, and Chlorella pyrenoidosa. C. vulgaris, among other strains of microalgae, showed the highest growth rate (1.17 optical density/5 days). Cultivating conditions for C. vulgaris that produced the highest growth rate were at concentrations of 243 ${\mu}g\;CO_2$/mL, 10 mM ammonia, and 1 mM phosphate, with an initial pH range of 7-8.

Identification and Optimal Characteristics of Burkholderia sp. SKK381 Degrading Benzene (Benzene 분해 Burkholderia sp. SKK381 분리 및 최적 특성)

  • 강동일;김철경;고창웅;진환준;김장규;김남기
    • KSBB Journal
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    • v.15 no.6
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    • pp.589-593
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    • 2000
  • Several bacterial strains growing on benzene minimal medium were isolated from soil by enrichment culture, Burkholderia sp. SKK381 was identified and selected. In order to determine the ability of Burkholderia sp. SKK381 to degrade benzene. Changes in substrate concentration, cell growth, and pH were monitored from start-up in bath culture. At 30$^{\circ}C$, 1000 ppm of benzene was degraded 100% within 28hours. Cell growth conditions were best at an initial pH of 7.0 and a benzene concentration of 1000 ppm at 30$^{\circ}C$.

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Utilization of Ferroproteins by Candida albicans during Candidastasis by Apotransferrin

  • Han, Yong-Moon
    • Archives of Pharmacal Research
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    • v.28 no.8
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    • pp.963-969
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    • 2005
  • Many reports have stated that some of the pathogenic bacteria can obtain iron from ferroproteins, such as cytochrome C, ferritin, hemin, hemoglobin, and myoglobin. These reports prompted us to determine if an opportunistic pathogenic fungus, Candida albicans, can utilize ferroproteins to circumvent the iron-regulatory effect of transferrin. The following assays were carried out to measure in vitro growth stimulation by the ferroproteins: as an initial step, C. albicans was cultured in iron-free (pretreated with apotransferrin for 24h) culture medium. Once Candida albicans yeast cell growth reached stasis from iron starvation, individual ferroproteins were added to the culture media. Results showed that hemin, hemoglobin, and myoglobin supported a partial growth recovery. Additional studies with haptoglobin, a serum protein that interacts with the globin moiety of certain ferroproteins, established that C. albicans could obtain iron from the haptoglobin-ferroprotein complexes. These data indicate that the heme part of the ferroproteins is the source of iron. This implies that heme oxygenase, CaHMX1 might be involved in bringing about dissociation of heme-containing protein for iron-acquisition. In addition, anticandidal activity of transferrin takes place not only by the process of iron regulation, but also by direct interaction with the yeast cells.

Sarcomatoid carcinoma of the mandible: report of a case (하악에 발생한 sarcomatoid carcinoma: 증례보고)

  • Kwon, Gui-Young;Choi, Young-Jun;Song, Min-Seok;Yun, Kyoung-In
    • Journal of the Korean Association of Oral and Maxillofacial Surgeons
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    • v.36 no.3
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    • pp.228-230
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    • 2010
  • Sarcomatoid carcinoma is a rare and occurs mainly in the upper aerodigestive tract such as the oral cavity, esophagus and vocal cords. It is a unique variant of squamous cell carcinoma. We report the case of a patient with spindle cell squamous cell carcinoma involving the mandible. At initial examination, overlying mucosa of that lesion was normal appearance. One week later, that lesion showed ulcerative and bloody change and rapid growth in size. This case showed unpredictable rapid growth although rapid growth in size was suspected of undergoing malignancy.

Metalorganic chemical vapor deposition of semiconducting ZnO thin films and nanostructures

  • Kim Sang-Woo
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.16 no.1
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    • pp.12-19
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    • 2006
  • Metalorganic chemical vapor deposition (MOCYD) techniques have been applied to fabricate semiconducting ZnO thin films and nanostructures, which are promising for novel optoelectronic device applications using their unique multifunctional properties. The growth and characterization of ZnO thin films on Si and $SiO_2$ substrates by MOCYD as fundamental study to realize ZnO nanostructures was carried out. The precise control of initial nucleation processes was found to be a key issue for realizing high quality epitaxial layers on the substrates. In addition, fabrication and characterization of ZnO nanodots with low-dimensional characteristics have been investigated to establish nanostructure blocks for ZnO-based nanoscale device application. Systematic realization of self- and artificially-controlled ZnO nanodots on $SiO_2/Si$ substrates was proposed and successfully demonstrated utilizing MOCYD in addition with a focused ion beam technique.

Allometry, Basal Area Growth, and Volume Equations for Quercus mongolica and Quercus variabilis in Gangwon Province of Korea

  • Choi, Jung-Kee;You, Byung-Oh;Burkhart, Harold E.
    • Journal of Korean Society of Forest Science
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    • v.96 no.2
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    • pp.189-196
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    • 2007
  • Allometry, basal area equations, and volume equations were developed with various tree measurement variables for the major species, Quercus mongolica and Quercus variabilis, in Korean natural hardwood forests. For allometry models, the relationships between total height-DBH, crown width-DBH, height to the widest portion of the crown-total height, and height to base of crown-total height were investigated. Multiple regression methods were used to relate annual basal area growth to tree variables of initial size (DBH, total height, crown width) and relative size (relative diameter, relative height) as well as competition measures (competition index, crown class, exposed crown area, percent exposed crown area, live crown ratio). For tree volume equations, the combined-variable and Schumacher models were fitted with DBH, total height and crown width for both species.