• 제목/요약/키워드: Growth conditions

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MOCVD 성장조건이 InN/GaN 다층박막의 발광세기에 미치는 영향 (The Effect of MOCVD Growth Parameters on the Photolumenescence Intensity of InN/GaN Multi-layers)

  • 김현수;이정주;정순영;이정용
    • 한국재료학회지
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    • 제12권3호
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    • pp.190-194
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    • 2002
  • InN/GaN multi-layers were grown by metalorganic chemical vapor deposition(MOCVD) in order to get the appropriate structure for an high power blue-green light emitting diode(LED), and effects of growth conditions (growth temperature, pressure, and $trimethylindium(TMIn)-NH_3-N_2\; flow\; rare)$ on the integrated photoluminescence (PL) intensity and PL peak energy in InN/GaN multi-layers were investigated. The optimized growth conditions with the highest integrated PL intensity for InN/GaN multi-layers were obtained: the growth temperature at $780^{\circ}C$, the growth pressure at 325 Torr, the TMIn flow rate with 150 $m\ell$/min, the $NH_3$flow rate with 3.2 ι/min, and $N_2$ flow rate with 2 ι/min.

The flux pinning properties of BaSnO3-added GdBa2Cu3O7-δ films with varying growth conditions

  • Lee, J.K.;Oh, J.Y.;Lee, J.M.;Kang, W.N.;Kang, B.
    • 한국초전도ㆍ저온공학회논문지
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    • 제19권3호
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    • pp.18-22
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    • 2017
  • Addition of $BaSnO_3$ (BSO) to $GdBa_2Cu_3O_{7-{\delta}}$ (GdBCO) is reported to enhance the flux pinning property of GdBCO thick films. To investigate the effect of growth condition on the pinning properties, 700 nm-thick BSO-added GdBCO films deposited with varying temperatures and growth rates were prepared by using a pulsed laser deposition method. As the deposition temperature increases, the critical current density and the pinning force density show an improved field dependence up to $750^{\circ}C$ due to the increase in the formation of the a-axis growth and the BSO nanostructures. The films deposited at higher temperatures show degraded surfaces and as a result, degraded pinning behaviors. For the change in growth rate, the critical current density and the pinning force increase as the repetition rate increase at low magnetic fields, but this behavior is reversed in high magnetic fields. These results indicate that the film growth conditions significantly affect the formation of BSO nanostructures and the pinning properties of BSO-added GdBCO films.

The Dynamics of Economic Growth in Underdeveloped Regions: A Case Study in Indonesia

  • JUMONO, Sapto;BASKARA, Ika;ABDURAHMAN, Abdurrahman;MALA, Chajar Matari Fath
    • The Journal of Asian Finance, Economics and Business
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    • 제8권4호
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    • pp.643-651
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    • 2021
  • This study aims to determine the response of regional economic growth to the financial performance of regional economies in regard to the liquidity conditions, saving-investment gaps, trade openness, inflation, as well as the national economic growth. The basic logic theory of research uses the principles of open economics and financial intermediary systems. The data used in this study are secondary data, and the form of data is a quarterly time series for the period from 2008 to 2019. The data were obtained from various publications, such as the Central Statistics Agency (CSA), Regional Financial Economics Statistics (RFES), Indonesian Banking Statistics (IBS), and the Financial Services Authority (FSA). Data processing was done through VAR/VECM analysis; short-term and long-term equilibrium analyses were carried out. The results of the analysis illustrate that regional economic growth and the conditions of liquidity, saving-investment gaps, trade openness, inflation, and national economic growth are related and lead to significant impact variations in the provinces of Papua and West Papua. In conclusion, the findings of this research support the leading supply hypothesis and reformulate the strategy and policy of economic development, bearing in mind that there are still many underdeveloped districts in these two provinces.

A review of experimental and numerical studies on crack growth behaviour in rocks with pre-existing flaws

  • G. Sivakumar;V.B. Maji
    • Geomechanics and Engineering
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    • 제35권4호
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    • pp.333-366
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    • 2023
  • Rock as a mass generally exhibits discontinuities, commonly witnessed in rock slopes and underground structures like tunnels, rock pillars etc. When these discontinuities experiences loading, a new crack emerges from them which later propagates to a macro scale level of failure. The failure pattern is often influenced by the nature of discontinuity, geometry and loading conditions. The study of crack growth in rocks, namely its initiation and propagation, plays an important role in defining the true strength of rock and corresponding failure patterns. Many researchers have considered the length of the discontinuity to be fully persistent on rock or rock-like specimens by both experimental and numerical methods. However, only during recent decades, there has been a substantial growth in research interest with non-persistent discontinuities where the crack growth and its propagation phenomenon were found to be much more complex than persistent ones. The non-persistence fractures surface is generally considered to be open and closed. Compared to open flaws, there is a difference in crack growth behaviour in closed or narrow flaws due to the effect of surface closure between them. The present paper reviews the literature that has contributed towards studying the crack growth behaviour and its failure characteristics on both open and narrow flaws subjected to uniaxial and biaxial compression loading conditions.

Selection of laccase over-secreting mutant

  • Kim, Soon-Ja;Choi, Hyoung-Tae
    • Journal of Microbiology
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    • 제33권2호
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    • pp.146-148
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    • 1995
  • Coprinus congregatus has a membrane-associated laccase which is not secreted into culture media. A mutant monokaryon obtained, by U. V. irradiation followed by protoplast generation and regeneration method, was successfully isolated. When the mutant was grown on a agar plate or in a liquid medium, it secreted laccase while the wild type did not under the same growth conditions. The laccase of the mutant was compared with that of wild type did not under the same growth conditions. The laccase of the mutant was compared with that of wild type of native PAGE analysis, and showed identical mobility.

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EFFECT OF POLING ON THE PHYSICAL PIEZOELECTRIC PROPERTIES OF $LiNbO_3$

  • Han, Ji-Woong;Kyung Joo;Shim, Kwang-Bo;Auh, Keun-Ho
    • 한국결정성장학회:학술대회논문집
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    • 한국결정성장학회 1998년도 PROCEEDINGS OF THE 14TH KACG TECHNICAL MEETING AND THE 5TH KOREA-JAPAN EMGS (ELECTRONIC MATERIALS GROWTH SYMPOSIUM)
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    • pp.133-136
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    • 1998
  • Undoped and 5mol%MgO DOPED {{{{ { LiNbO}_{ 3} }}}} were grown by floating zone method. The grown crystals were poled to c-azis in different electric conditions. Ferroelectric domain patterns related to the poling conditions were investigated by chemical etching and the poling effects on the piezoelectric in the undoped and MgO doped Crystals were studied.

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The Growth Kinetics of Tin Oxide Films from Tetramethyltin

  • 이상운;윤천호
    • Bulletin of the Korean Chemical Society
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    • 제20권9호
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    • pp.1031-1034
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    • 1999
  • Tin oxide films have been grown employing the chemical vapor deposition technique under reduced pressure conditions using tetramethyltin as the precursor and oxygen as the oxidant. An activation energy derived for the deposition reaction under representative deposition conditions has a value of 89±3 kJ mol-1, suggesting a typical kinetic control. Deposition rates of tin oxide films exhibit a near first order dependence on tetramethyltin partial pressure and a zeroth order dependence on oxygen partial pressure. This study provides the first quantitative information about the growth kinetics of tin oxide films from tetramethyltin by the cold-wall low-pressure chemical vapor deposition.

EFG법에 의한 ${\gamma}-6Bi_2O_3 {\cdot}SiO_2$(BSO)단결정의 육성 (Growth of ${\gamma}-6Bi_2O_3 {\cdot}SiO_2$( Single Crystals by EFG Method)

  • 김호건;유건종
    • 한국결정성장학회지
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    • 제1권1호
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    • pp.26-38
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    • 1991
  • 광기능소자로 응용성이 넓은 전기광학결정 $r-6Bi_2O_3{\cdot}SiO_2$(이하 BSO로 약칭)을 EFG(Edge-defined Film-fed Growth)법에 의하여 판상단결정으로 육성하는 기초적 조건을 조사하고 육성된 판단결정의 characterization 및 평가와 물성측정을 하였다. 본 연구에서 얻어진 최적성장조건은 온도구배가 $24^{\circ}C/cm$, 인상속도는 2.0mm/h이었다. 결정성장 최적조건에서 육성된 BSO결정은 제 2상의 석출이 없고 grain boundary가 존재하지 않으며 X선 분석으로도 단결정임이 확인되었다. 육성된 판상단결정의 판면은 (100)면이었고 결정성장 방위는 <100>이었다. 육성된 판상단결정은 편광현미경하에서는 pore, void, inclusion, striation 등의 성장결함이 없는 양질의 단결정이었으나 미세결함인 전위(dislocation)의 존재가 확인되었고 전위밀도는 $5.1{\times}10^5/\textrm{cm}^2$이었다.

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Application of Rhizobacteria for Plant Growth Promotion Effect and Biocontrol of Anthracnose Caused by Colletotrichum acutatum on Pepper

  • Lamsal, Kabir;Kim, Sang Woo;Kim, Yun Seok;Lee, Youn Su
    • Mycobiology
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    • 제40권4호
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    • pp.244-251
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    • 2012
  • In vitro and greenhouse screening of seven rhizobacterial isolates, AB05, AB10, AB11, AB12, AB14, AB15 and AB17, was conducted to investigate the plant growth promoting activities and inhibition against anthracnose caused by Colletotrichum acutatum in pepper. According to identification based on 16S rDNA sequencing, the majority of the isolates are members of Bacillus and a single isolate belongs to the genus Paenibacillus. All seven bacterial isolates were capable of inhibiting C. acutatum to various degrees. The results primarily showed that antibiotic substances produced by the selected bacteria were effective and resulted in strong antifungal activity against the fungi. However, isolate AB15 was the most effective bacterial strain, with the potential to suppress more than 50% mycelial growth of C. acutatum in vitro. Moreover, antibiotics from Paenibacillus polymyxa (AB15) and volatile compounds from Bacillus subtilis (AB14) exerted efficient antagonistic activity against the pathogens in a dual culture assay. In vivo suppression activity of selected bacteria was also analyzed in a greenhouse with the reference to their prominent in vitro antagonism efficacy. Induced systemic resistance in pepper against C. acutatum was also observed under greenhouse conditions. Where, isolate AB15 was found to be the most effective bacterial strain at suppressing pepper anthracnose under greenhouse conditions. Moreover, four isolates, AB10, AB12, AB15, and AB17, were identified as the most effective growth promoting bacteria under greenhouse conditions, with AB17 inducing the greatest enhancement of pepper growth.

Analysis of Hygrothermal Performance of Wood Frame Walls according to Position of Insulation and Climate Conditions

  • Kang, Yujin;Chang, Seong Jin;Kim, Sumin
    • Journal of the Korean Wood Science and Technology
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    • 제44권2호
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    • pp.264-273
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    • 2016
  • The insulation of a building envelope influences the hygrothermal performance as well as the thermal performance of the building. While most of Korean wood frame houses have an interior insulation system, the exterior insulation system with high thermal performance has recently been applied. While it can be effective in energy savings for better insulation performance, without consideration of the moisture, condensation and mould growth can occur. Therefore, in this study, hygrothermal behaviour, water content, and mould growth were analyzed using hygrothermal simulation of an exterior wall of a wood frame house with which the interior insulation and exterior insulation systems were applied. The wall layer included Wall A (Interior insulation) and Wall B (Exterior insulation). The U-values were identified as 0.173 and $0.157W/m^2K$, respectively. The total water content and OSB absolute water content of Wall A were confirmed to be higher than those of Wall B, but the absolute water content did not exceed the reference value of 20%. The moisture content of the two walls was determined to be stable in the selected areas. However, mould growth risk analysis confirmed that both Wall A and Wall B were at risk of mould growth. It was confirmed that as the indoor setting temperature decreased, the mould index and growth rate in the same area increased. Therefore, the mould growth risk was affected more by indoor and outdoor climate conditions than by the position of the insulation. Consequently, the thermal performance of Wall B was superior to that of Wall A but the hygrothermal performances were confirmed to be similar.