• Title/Summary/Keyword: Formation and growth mechanisms

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An In-Situ Optical Study on Silicon Crystallization Process Using an Excimer Laser (Excimer Laser응용 실리콘 결정화 공정에 대한 In-Situ 광학적 연구)

  • Kim, W.J.;Y, C.-Hwan;Park, S.H.;Kim, H.J.
    • Proceedings of the KSME Conference
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    • 2003.04a
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    • pp.1407-1411
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    • 2003
  • Due to the heat confinement in the shallow region of the target for a short time scale, pulsed laser annealing has received increasing interest for the fabrication of poly-Si thin film transistors(TFTs) on glass as a low cost substrate in the flat panel displays. The formation and growth mechanisms of poly silicon(poly-Si) grains in thin films are investigated using an excimer laser crystallization system. To understand the crystallization mechanism, the grain formations are observed by FESEM analysis. The optical reflectance and transmittance during the crystallization process are measured using HeNe laser optics. A two-step ELC(Excimer Laser Crystallization) process is applied to enhance the grain formation uniformity.

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An Optical Study on ELC Process of Amorphous Silicon (비정질 실리콘의 ELC 공정에 대한 광학적 연구)

  • 김우진;윤창환;박승호;김형준
    • Laser Solutions
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    • v.6 no.2
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    • pp.9-17
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    • 2003
  • Due to the heat confinement in the shallow region of the target for a short time scale, pulsed laser annealing has received an increasing interest for the fabrication of poly-Si thin film transistors(TFTs) on glass as a low cost substrate in the flat panel displays. The formation and growth mechanisms of poly silicon(poly-Si) grains in thin films are investigated using an excimer laser crystallization system. To understand the crystallization mechanism, the grain formations are observed by FESEM photography. The optical reflectance and transmittance during the crystallization process are measured using HeNe laser optics. A two-step ELC(Excimer Laser Crystallization) process is applied to enhance the grain formation uniformity.

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6H-SiC single crystal growth by the sublimation method : (I) the formation mechanism of growth defects (승화법에 의한 6H-SiC 단결정 성장 : (I) 성장결함생성기구)

  • Kim, Hwa-Mok;Kang, Seung-Min;Joo, Kyoung;Shim, Kwang-Bo;Auh, Keun-Ho
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.7 no.2
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    • pp.185-190
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    • 1997
  • The 6H-SiC single crystals were grown using a self-designed crystal grower by the sublimation method. The grown crystals were typically 30 mm in diameter and 10 mm in length. Optimum growth conditions were established as follows : the temperature of the raw material was $2150~2250^{\circ}C$, the temperature of the substrate was $1950~2050^{\circ}C$, the temperature difference between the raw material and substrate was about $200^{\circ}C$, growth pressure was 50~200 torr and growth rate was 300~700 $\mu\textrm{m}$/hr. Optical microscopy was used for observing the surface of the 6H-SiC single crystal grown and the phenomenological approach was performed on the formation mechanism of the defects in the 6H-SiC crystal. Especially, the micropipes in the as-grown surface were examined to determine the formation mechanisms of the micropipes.

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Methodological Approaches to Estimation of Economic Growth and Sustainable Development: Kazakhstan's Experience

  • NURLANOVA, Nailya K.;OMAROV, Akedil K.;SATPAYEVA, Zaira T.
    • The Journal of Asian Finance, Economics and Business
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    • v.7 no.4
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    • pp.317-324
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    • 2020
  • The study aims to analyze the theoretical background of the economic growth and sustainable development; systematization of scientists view on monitoring and economic and innovative evaluation, analysis and diagnosis of factors affecting these processes. Rating characteristics of the level of innovative resources development obtained based on the comparative analysis of Kazakhstan regions. Calculations were done based on official statistics during 2010 and 2015-2017. Based on obtained data there has been grading of the country regions and their ratings were determined by the level of development of innovative resources. This research identifies areas and mechanisms to ensure balanced sustainable development of the national economy. The findings suggest that sustainable development of the state is affected by the innovative activity of the regions, the sustainable development of which is ensured by innovative enterprises. Transition to the model of sustainable territorial development involves the formation of such conditions and the use of mechanisms under which the natural base of this development is not destroyed, the environment suitable for human existence is preserved and reproduced. The findings of this research support for pursuing a national policy of reducing regional imbalances, and promoting a more balanced and sustainable development of the whole country.

Correlation defects of macrostructure with morphology of BGO crystals grown by low thermal gradient Czochralski technique

  • Shlegel, V.N.;Shubin, Yu.V.;Ivannikova, N.V.
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.13 no.1
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    • pp.1-4
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    • 2003
  • In the present work we consider morphological structure of the faces of BGO crystals grown by Czochralski technique under the conditions of low temperature gradient (0.1~1 deg/cm) and interconnection between the morphological features of faces at the crystallization front and the formation of defects within the crystal volume. It is demonstrated that the {112} faces retain stability while the growing surface deviates from the crystallographic (112) plane up to 1 degree. At larger deviation, the region of the stable facet growth passes either to the region of macrosteps or to the region of normal growth. depending on conditions.

Biological and Structural Mechanisms of Disease Development and Resistance in Chili Pepper Infected with the Root-knot Nematode

  • Moon, Hyo-Sun;Khan, Zakaullah;Kim, Sang-Gyu;Son, Seon-Hye;Kim, Young-Ho
    • The Plant Pathology Journal
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    • v.26 no.2
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    • pp.149-153
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    • 2010
  • Biological and structural mechanisms of the nematode disease development in chili pepper caused by the root-knot nematode, Meloidogyne incognita, were investigated. Out of 39 chili pepper cultivars/lines tested, six were found resistant, while 33 were susceptible to M. incognita, of which a susceptible cultivar Chilseongcho and three resistant cultivar/lines CM334, 02G132 and 03G53 with different resistance degrees were selected for microscopic studies on the disease development. Gall formation was greatly reduced in the resistant cultivars/lines. Nematode penetration occurred both in the susceptible and resistant chili pepper roots; however, the penetration rates were significantly lowered in the three resistant peppers compared to the susceptible pepper cv. Chilseongcho. In the susceptible pepper, giant cells were extensively formed with no discernible necrosis around the nematode feeding sites. In the highly resistant pepper cultivar CM334, no giant cell was formed, but extensive necrosis formation was observed around the penetrating nematodes. In the other two resistant pepper lines (02G132 and 03G53), both giant cells and prominent necroses were formed, and the necrotic responses appeared to inhibit the further development of giant cells or accelerate their early degeneration. Although the nematode penetration was retarded significantly in the resistant cultivar/lines, all of the above results suggest that the disease resistance of pepper may be related to post-infectional defense mechanisms (nematode growth and development) more than pre-infectional ones (penetration and establishment). Variations in structural modifications in the resistant cultivar/lines may reflect their genetic differences related to the nematode resistance.

Influence of Ectomycorrhizal Colonization on Cesium Uptake by Pinus densiflora Seedlings

  • Ogo, Sumika;Yamanaka, Takashi;Akama, Keiko;Nagakura, Junko;Yamaji, Keiko
    • Mycobiology
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    • v.46 no.4
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    • pp.388-395
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    • 2018
  • Radionuclides were deposited at forest areas in eastern parts of Japan following the Fukushima Daiichi Nuclear Power Plant incident in March 2011. Ectomycorrhizal (EM) fungi have important effects on radiocaesium dynamics in forest ecosystems. We examined the effect of colonization by the EM fungus Astraeus hygrometricus on the uptake of cesium (Cs) and potassium (K) by Pinus densiflora seedlings. Pine seedlings exhibited enhanced growth after the EM formation due to the colonization by A. hygrometricus. Additionally, the shoot Cs concentration increased after the EM formation when Cs was not added to the medium. This suggests that A. hygrometricus might be able to solubilize Cs fixed to soil particles. Moreover, the shoot K concentration increased significantly after the EM formation when Cs was added. However, there were no significant differences in the root K concentration between EM and non-EM seedlings. These results suggest that different mechanisms control the transfer of Cs and K from the root to the shoot of pine seedlings.

Norcantharidin Anti-Angiogenesis Activity Possibly through an Endothelial Cell Pathway in Human Colorectal Cancer

  • Yu, Tao;Hou, Fenggang;Liu, Manman;Zhou, Lihong;Li, Dan;Liu, Jianrong;Fan, Zhongze;Li, Qi
    • Asian Pacific Journal of Cancer Prevention
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    • v.13 no.2
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    • pp.499-503
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    • 2012
  • The present study was based on the unexpected discovery that norcantharidin exerted anti-angiogenesis activity when effects on growth of human colon cancer were studied. The aim was to further verify this finding and explore possible mechanisms using a tumor xenograft model in nude mice. We confirmed that norcantharidin (5 or 15 mg/kg) could inhibit angiogenesis of human colon cancer in vivo. In vitro, crossing river assay, cell adhesion assay and tube formation assay indicated that NCTD could reduce the migration, adhesion and vascular network tube formation ability of HUVECs. At the same time, the expression levels of VEGF and VEGFR-2 proteins which play important roles in angiogenesis were reduced as examined by western blotting analysis. Taken together, the results firstly showed NCTD could inhibit angiogenesis of human colon cancer in vivo, probably associated with effects on migration, adhesion and vascular network tube formation of HUVECs and expression levels of VEGF and VEGFR-2 proteins.

Ginsenoside Rg1 promotes neurite growth of retinal ganglion cells through cAMP/PKA/CREB pathways

  • Ye-ying Jiang ;Rong-yun Wei;Kai Tang;Zhen Wang;Ning-hua Tan
    • Journal of Ginseng Research
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    • v.48 no.2
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    • pp.163-170
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    • 2024
  • Background: Mechanisms of synaptic plasticity in retinal ganglion cells (RGCs) are complex and the current knowledge cannot explain. Growth and regeneration of dendrites together with synaptic formation are the most important parameters for evaluating the cellular protective effects of various molecules. The effect of ginsenoside Rg1 (Rg1) on the growth of retinal ganglion cell processes has been poorly understood. Therefore, we investigated the effect of ginsenoside Rg1 on the neurite growth of RGCs. Methods: Expression of proteins and mRNA were detected by Western blot and qPCR. cAMP levels were determined by ELISA. In vivo effects of Rg1 on RGCs were evaluated by hematoxylin and eosin, and immunohistochemistry staining. Results: This study found that Rg1 promoted the growth and synaptic plasticity of RGCs neurite by activating the cAMP/PKA/CREB pathways. Meanwhile, Rg1 upregulated the expression of GAP43, Rac1 and PAX6, which are closely related to the growth of neurons. Meantime, H89, an antagonist of PKA, could block this effect of Rg1. In addition, we preliminarily explored the effect of Rg1 on enhancing the glycolysis of RGCs, which could be one of the mechanisms for its neuroprotective effects. Conclusion: Rg1 promoted neurite growth of RGCs through cAMP/PKA/CREB pathways. This study may lay a foundation for its clinical use of optic nerve diseases in the future.

Anti-wrinkling effects of "L-Skin Care" and molecular mechanisms on hairless mouse skin caused by chronic ultraviolet B irradiation.

  • Cho, Ho-Song
    • Proceedings of the Korean Society of Applied Pharmacology
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    • 2007.11a
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    • pp.153-158
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    • 2007
  • Background: Naturally occurring antioxidants were used to regulate the skin damage caused by ultraviolet (UV) radiation because several antioxidants have demonstrated that they can inhibit wrinkle formation through prevention of matrix metalloproteinases (MMPs) and/or increase of collagen synthesis. We examined the effect of oral administration of the antioxidant mixture ("L-Skin Care") on UVB-induced wrinkle formation. In addition, we investigated the possible molecular mechanisms of photoprotection against UVB through inhibition of collagen-degrading MMP activity or through enhancing of pro collagen synthesis in mouse dorsal skin. Methods: Female SKH-l hairless mice were orally administrated "L-Skin Care" (test group) or vehicle (control group) for 10 weeks with UVB irradiation by three times a week. The intensity of irradiation was gradually increased from 30 to $180mJ/cm^2$. Microtopographic and histological assessments of the dorsal skins were carried out at the end of 10 weeks to evaluate wrinkle formation. Western blot analysis and EMSA were also carried out to investigate the changes in the balance of collagen synthesis and collagen degradation. Results: Our "L-Skin Care" significantly reduced UVB-induced wrinkle formation, accompanied by significant reduction of epidermal thickness, and UVB-induced hyperplasia, acanthosis and hyperkeratosis. Oral administration of "L-Skin Care" significantly prevented UVB-induced expressions of MMPs, mitogen-activated protein (MAP) kinases and activation of activator protein (AP)-1 transcriptional factor in addition to enhanced type I procollagen and transforming growth factor-$\beta$ (TGF-$\beta$) expression. Conclusion: Oral administration of "L-Skin Care" significantly inhibited wrinkle formation caused by chronic UVB irradiation through significant inhibition of UVB-induced MMP activity accompanied with enhancement of collagen synthesis.

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