• Title/Summary/Keyword: sessile

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Magnetically Driven Assemblies of γ-Fe3O4 Nanoparticles into Well-Ordered Permanent Structures

  • Byun, Myunghwan
    • Journal of Powder Materials
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    • v.24 no.3
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    • pp.229-234
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    • 2017
  • We report on a simple and robust route to the spontaneous assembly of well-ordered magnetic nanoparticle superstructures by irreversible evaporation of a sessile single droplet of a mixture of a ferrofluid (FF) and a nonmagnetic fluid (NF). The resulting assembled superstructures are seen to form well-packed, vertically arranged columns with diameters of $5{\sim}0.7{\mu}m$, interparticle spacings of $9{\sim}2{\mu}m$, and heights of $1.3{\sim}3{\mu}m$ The assembled superstructures are strongly dependent on both the magnitude of magnetic field and the mixing ratio of the mixture. As the magnitude of the externally applied magnetic field and the mixing ratio of the mixture increase gradually, the size and interspacing of the magnetic nanoparticle aggregations decrease. Without an externally applied magnetic field, featureless patterns are observed for the ${\gamma}-Fe_3O_4$ nanoparticle aggregations. The proposed approach may lead to a versatile, cost-effective, fast, and scalable fabrication process based on the field-induced self-assembly of magnetic nanoparticles.

A Study for Joining of Alumina Soldered by SiO$_2$-CaO-A1$_2$O$_3$ Glasses (SiO$_2$-CaO-Al$_2$O$_3$계 유리 솔더에 의한 알루미나의 접합 현상에 관한 연구)

  • 안병국
    • Journal of Welding and Joining
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    • v.21 no.2
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    • pp.35-41
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    • 2003
  • Sintered alumina ceramics were joined by 2 kinds of SiO$_2$-CaO-A1$_2$O$_3$ glass solders having a similar expansivity as alumina. Wetting of glass/alumina was examined by sessile drop method. The observation of interface and bending strength related to alumina/glass/alumina systems were investigated by means of SEM/EDX and 4-point bending test. the result are summarized as follow: (1) Wetting of glass solders on alumina was good at temperatures higher than 145$0^{\circ}C$. (2) When the joining temperature wan high, diffusion and/or reactions between solder md alumina took place at the interface. These diffusions and reactions occurring at the interface greatly affected the bending strength of joining body. (3) Highest strength corresponding to 80% that of alumina was obtained by the solder of 35SiO$_2$-35CaO-30A1$_2$O$_3$(wt%) glass.

PIF4 Integrates Multiple Environmental and Hormonal Signals for Plant Growth Regulation in Arabidopsis

  • Choi, Hyunmo;Oh, Eunkyoo
    • Molecules and Cells
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    • v.39 no.8
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    • pp.587-593
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    • 2016
  • As sessile organisms, plants must be able to adapt to the environment. Plants respond to the environment by adjusting their growth and development, which is mediated by sophisticated signaling networks that integrate multiple environmental and endogenous signals. Recently, increasing evidence has shown that a bHLH transcription factor PIF4 plays a major role in the multiple signal integration for plant growth regulation. PIF4 is a positive regulator in cell elongation and its activity is regulated by various environmental signals, including light and temperature, and hormonal signals, including auxin, gibberellic acid and brassinosteroid, both transcriptionally and post-translationally. Moreover, recent studies have shown that the circadian clock and metabolic status regulate endogenous PIF4 level. The PIF4 transcription factor cooperatively regulates the target genes involved in cell elongation with hormone-regulated transcription factors. Therefore, PIF4 is a key integrator of multiple signaling pathways, which optimizes growth in the environment. This review will discuss our current understanding of the PIF4-mediated signaling networks that control plant growth.

Pharmacognostic Evaluation of Curcuma aeurigenosa Roxb.

  • Srivastava, Sharad;Nitin, Chitranshi;Srivastava, Sanjay;Dan, Mathew;Rawat, A.K.S.;Pushpangadan, Palpu
    • Natural Product Sciences
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    • v.12 no.3
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    • pp.162-165
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    • 2006
  • Curcuma aeruginosa Roxb. (FamilyZingeberaceae), commonly known as 'pink and blue giner' is widely used in Indian system of medicine since time immemorial. The plant is found well in wild habitat and cultivated in southern India. The plant is distinguished by red corolla lobes and ferruginous or greenish-blue rhizome. Rhizoma is used medicinally as anti-diarrheal, anti-fungal; external use as astringent for wounds. A detailed pharmacognostic evaluation of its rhizome showed total ash 6.1%, acid insoluble ash 1.20%, alcohol soluble extractives 3.70% , water soluble extractives 14.50%, sugar 20.93%, starch 41.85%, and tannins 0.68%. Oh hydro distillation, the rhizomes and sessile tubers yielded 0.17% oil.

Wettability of Zn and Zn-Al alloy (Zn와 Zn-Al 합금의 젖음성)

  • Kim, Su-Yeong;Bae, Dae-Cheol;Jin, Yeong-Sul
    • Proceedings of the Korean Institute of Surface Engineering Conference
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    • 2009.05a
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    • pp.122-122
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    • 2009
  • 금속기판과 액체금속의 젖음성은 일반적으로 액적법 (sessile drop)에 의해 고체와 액체간의 접촉각 측정을 통해서 알 수 있다. 이러한 방법에 의한 젖음성 실험결과는 고체와 액체계면에서의 반응이 무시될 수 있는 경우에 적용가는 하지만 연속용용도금공정과 같이 용융된 금속내부로 강판이 인입되는 과정에서 계면반응이 동적으로 진행되는 과정에서의 젖음성을 모사하기에는 이러한 방법의 신뢰성이 떨어지는 문제점이 있다. 따라서 본 연구에서는 실제 용융도금공정과 유사하게 소둔열처리된 저탄소강판이 환원성분위기내에서 Zn 및 Zn-Al 용융도금욕 내부로 연속적으로 인입되는 과정에서의 젖음력 및 접촉각 등의 측정을 통해 실제 도금공정상의 도금성과 젖음성의 연관성을 규명하고자하였다. 연구결과 일반적인 Zn 도금욕의 경우 젖음성이 양호하지만 Al함량이 높은 경우에는 젖음성이 좋지 못한 것으로 나타났다.

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Utilization of Native Plants for Highway Landscaping (자생초화류의 고속도로 조경식물 활용성 연구)

  • Jeon, Gi-Seong;Jung, Tae-Geun;So, Jae-Hyun
    • Journal of the Korean Society of Environmental Restoration Technology
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    • v.2 no.4
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    • pp.74-84
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    • 1999
  • The purpose of this study was to figure out the utilization of native plants for highway landscape. The field and nursery experiments were conducted from January of 1996 to December of 1998 on the Chonju Arboretum and Honam highway in Korea Highway Corporation. We have investigated thirty species of native plants and came to a conclusion that Chrysanthemum zawadskii var. latilobum, Aster koraiensis, Iris nertschinskia, Fennisetum alopecuroides, Viola kapsanensis are very suitable for highway landscaping. And, if the problems raised during this investigation are resolved, it is clear that Polygonatum odoratum var. plurijlorum, Belamcanda chinensis, Allium thunbergii, Ophiopogon japonicus, Dianthus superbus var. longicalycinus, Disporum sessile, Lilium tigrinum, Caryopteris incana, Aquilegia flabellata var. pumila, Pulsatilla koreana, Aster spathulifolius etc. can be useful plants at highway landscaping.

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A case report of giant right ventricular myxoma (거대 우심실 점액종 1례 보)

  • Park, Jae-Gil;Song, In-Seong;Lee, Hong-Gyun
    • Journal of Chest Surgery
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    • v.16 no.4
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    • pp.470-475
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    • 1983
  • Myxoma of the heart can now be successfully treated but the success is obviously dependent upon the correct diagnosis and treatment prior to development of catastrophic complications such as sudden death, embolism or cardiac failure. The right ventricular myxoma is very rare, and we treated successfully a case of giant right ventricular myxoma, sessile tumor originated from ventricular apex, weighed 175 gm. The tumor base was broad, about 3 cm x 3cm, and it was hardly adhesed to the tricuspid valvular structures, but could remove with the preservation of adequate residual ventricular chamber size and the maintenance of functional tricuspid valve anatomy. The postoperative course was excellent and uneventful.

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Wetting Behavior of Low Temperature Molten Frits on Various Ceramic Substrates (세라믹 기판에 대한 저온 용융프릿트의 침윤 거동)

  • 노태준;오근호;이종근;김대웅
    • Journal of the Korean Ceramic Society
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    • v.20 no.3
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    • pp.199-204
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    • 1983
  • An attempt was made to study wetting behavior of various low temperature molten frist on ceramic substrates including high alumina silicon carbide and porous fired clay plates by Sessile-drop method. The cosine values of contact angles between substrates and molten frist were linear as a function of temperature unless chemical reactions between substrate and molten frit occured. Addition of BaO to frit composition indicated that cosine of values of contact angles were gradually increased with increasing temperature but in the frist contained $Li_2O$ consine values were abruptly increased with increasing temperature after reached a certain temperature. The contact angle increased with increasing roughness of the substrate surface in case of alumina substrate plate.

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SNAREs in Plant Biotic and Abiotic Stress Responses

  • Kwon, Chian;Lee, Jae-Hoon;Yun, Hye Sup
    • Molecules and Cells
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    • v.43 no.6
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    • pp.501-508
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    • 2020
  • In eukaryotes, membraneous cellular compartmentation essentially requires vesicle trafficking for communications among distinct organelles. A donor organelle-generated vesicle releases its cargo into a target compartment by fusing two distinct vesicle and target membranes. Vesicle fusion, the final step of vesicle trafficking, is driven intrinsically by complex formation of soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs). Although SNAREs are well-conserved across eukaryotes, genomic studies revealed that plants have dramatically increased the number of SNARE genes than other eukaryotes. This increase is attributed to the sessile nature of plants, likely for more sensitive and harmonized responses to environmental stresses. In this review, we therefore try to summarize and discuss the current understanding of plant SNAREs function in responses to biotic and abiotic stresses.