• Title/Summary/Keyword: ablation

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Fabrication of $(Pb,La)TiO_3$ Thin Films by Pulsed Laser Ablation (레이저 어블레이션에 의한 $(Pb,La)TiO_3$ 박막의 제작)

  • Park, Jeong-Heum;Kim, Joon-Han;Lee, Sang-Yeol;Park, Chong-Woo;Park, Chang-Yub
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.11 no.2
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    • pp.133-137
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    • 1998
  • $(Pb_{0.72}La_{0.28})Ti_{0.93}O_3(PLT(28))$ thin films were fabricated by pulsed laser deposition. PLT films deposited on $Pt/Ti/SiO_2/Si$ at $600^{\circ}C$ had a preferred orientation in (111) plane and at $550^{\circ}C$ had a (100) preferred orientation. We found that (111) preferred oriented films had well grown normal to substrate surface. This PLT(28) thin films of $1{\mu}m$ thickness had dielectric properties of ${\varepsilon}_r$=1300, dielectric $loss{\fallingdotseq}0.03 $. and had charge storage density of 10 [${\mu}C/cm^2$] and leakage current density of less than $10^{-6}[A/cm^2]$ at 100[kV/cm]. These results indicated that the PLT(28) thin films fabricated by pulsed laser deposition are suitable for DRAM capacitor application.

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Organic matrix-free imaging mass spectrometry

  • Kim, Eunjin;Kim, Jisu;Choi, Inseong;Lee, Jeongwook;Yeo, Woon-Seok
    • BMB Reports
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    • v.53 no.7
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    • pp.349-356
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    • 2020
  • Mass spectrometry (MS) is an ideal tool for analyzing multiple types of (bio)molecular information simultaneously in complex biological systems. In addition, MS provides structural information on targets, and can easily discriminate between true analytes and background. Therefore, imaging mass spectrometry (IMS) enables not only visualization of tissues to give positional information on targets but also allows for molecular analysis of targets by affording the molecular weights. Matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) MS is particularly effective and is generally used for IMS. However, the requirement for an organic matrix raises several limitations that get in the way of accurate and reliable images and hampers imaging of small molecules such as drugs and their metabolites. To overcome these problems, various organic matrix-free LDI IMS systems have been developed, mostly utilizing nanostructured surfaces and inorganic nanoparticles as an alternative to the organic matrix. This minireview highlights and focuses on the progress in organic matrix-free LDI IMS and briefly discusses the use of other IMS techniques such as desorption electrospray ionization, laser ablation electrospray ionization, and secondary ion mass spectrometry.

Scoping Analysis of MCCI (Molten Core Concrete Interaction) at Plant Scale Using CORQUENCH Code (CORQUENCH 코드를 사용한 실규모 원자로의 노심용융물과 콘크리트 상호반응 해석)

  • Kim, Hwan-Yeol;Park, Jong-Hwa
    • 한국전산유체공학회:학술대회논문집
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    • 2008.03b
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    • pp.268-271
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    • 2008
  • If a reactor vessel is failed to retain a molten corium in a postulated severe accident, the molten corium is released outside the reactor vessel into a reactor cavity. The molten corium would attack the concrete wall and basemat of the reactor cavity, which may lead to inevitable concrete decompositions and possible radiological releases. In the OECD/MCCI project, a series of tests were performed to secure the data for cooling the molten corium spread out at the reactor cavity and for the long-term CCI (Core Concrete Interaction). Also, a MCCI (Molten Core Concrete Interaction) analysis code, CORQUENCH was upgraded at Argonne National Laboratory with embedding the new models developed for the tests. This paper deals with analyses of MCCI at plant scale under the conditions of top flooding using the upgraded CORQUENCH code. The modeling approach is briefly summarized first, followed by presentation of a validation calculation that illustrates the predicative capability of the modeling tool. With this background in place, the model is then used to carry out a parametric set of scoping calculations that define approximate coolability envelopes for the LCS (Limestone Common Sand) concrete that has been evaluated in the OECD/MCCI project.

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Effects of a Flow Guide on the Arcing History in a Thermal Puffer Plasma Chamber (유동 가이드가 열파퍼 플라즈마 챔버의 아크현상 이력에 미치는 영향)

  • Lee, Jong-Chul;Kim, Youn-Jea
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.31 no.10
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    • pp.832-839
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    • 2007
  • The geometry and dimensions of an expansion chamber are decisive factors in thermal puffer plasma chamber designs. Because they together dominate the temperature and speed at which the cooling gas from the chamber flows back through a flow channel to the arcing zone for the successful interruption of fault currents. In this study, we calculated the flow and mass transfer driven by arc plasma, and investigated the effects of a flow guide installed inside a thermal puffer plasma chamber. It is found that the existing cold gas of the chamber mixes with hot gases entrained from the arcing zone and is subjected to compression due to pressure build-up in the chamber. The pressure build-up with the flow guide is larger than that without due to a vortex which rotates clockwise around the chamber center. By the reverse pressure gradient, the mixing gas of the chamber flows back out for cooling down the residual plasma near current zero. In the case with the flow guide, the temperature just before current zero is lower than that without, and the Cu concentration with high electrical conductivity is also less than that without the flow guide.

nArgBP2 as a hub molecule in the etiology of various neuropsychiatric disorders

  • Lee, Sang-Eun;Chang, Sunghoe
    • BMB Reports
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    • v.49 no.9
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    • pp.457-458
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    • 2016
  • Recent studies have strongly implicated postsynaptic scaffolding proteins such as SAPAP3 or Shank3 in the pathogenesis of various mood disorders, including autism spectrum disorder, bipolar disorder (BD), and obsessive-compulsive disorders. Neural Abelson-related gene-binding protein 2 (nArgBP2) was originally identified as a protein that interacts with SAPAP3 and Shank3. Recent study shows that the genetic deletion of nArgBP2 in mice leads to manic/bipolar-like behavior resembling symptoms of BD. However, the function of nArgBP2 at synapse, or its connection with the synaptic dysfunctions, is completely unknown. This study provides compelling evidence that nArgBP2 regulates the spine morphogenesis through the activation of Rac1/WAVE/PAK/cofilin pathway, and that its ablation causes a robust and selective inhibition of excitatory synapse formation, by controlling actin dynamics. Our results revealed the underlying mechanism for the synaptic dysfunction caused by nArgBP2 downregulation that associates with analogous human BD. Moreover, since nArgBP2 interacts with key proteins involved in various neuropsychiatric disorders, our finding implies that nArgBP2 could function as a hub linking various etiological factors of different mood disorders.

A NUMERICAL STUDY ON JET IMPINGEMENT OF PULSED PLASMA DISCHARGE ON A FLAT PLATE (벽면에 충돌하는 펄스 플라즈마 제트 유동특성에 대한 수치적 연구)

  • Kim, K.;Kwak, H.S.;Park, J.Y.
    • Journal of computational fluids engineering
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    • v.14 no.1
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    • pp.70-77
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    • 2009
  • In this study, time-dependent numerical analysis was carried out to investigate the plasma jet impingement on a flat plate, and a compressible form of two-dimensional inviscid gas dynamics equations were solved using the flux corrected transport algorithm. The mathematical modeling of Joule heating in the polycarbonate capillary bore and the mass ablation from the bore wall was incorporated in the numerical analysis and the series of computation was performed for three cases depending on the distance of the opposing plate from the capillary exit. The computational results reveal that the presence of the opposing plate does not affect the flow conditions inside the capillary when compared to the case of open-air plasma discharge. In the exterior region, the flow structure shows the typical supersonic underexpanded jet which consists of the strong Mach disk in front of the opposing plate and the barrel shock at the side of the jet. It is found that the shock evolution becomes more quasi-steady when the plate distance decreases. Also, the effects of the distance between the capillary bore exit and the opposing plate on the flow conditions along the opposing plate are investigated and the pressure variation on the plate shows more complicated interaction between the plasma discharge and the opposing plate when the location of plate becomes closer to the capillary exit.

Preliminary Study of Seed Production of the Micronesian Mud Crab Scylla serrata (Crustacea: Portunidae) in Korea

  • Yi, Soon-Kil;Lee, So-Gwang;Lee, Jeong-Mee
    • Ocean and Polar Research
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    • v.31 no.3
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    • pp.257-264
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    • 2009
  • Seventeen females of the mud crab Scylla serrata, from the State of Kosrae, Micronesia, were transported to the Fisheries Resources Research Institute, Gyeongsangnam-do, in oxygen-filled plastic bags. After acclimatization to a $30^{\circ}C$ holding temperature, nine females were selected for seed production trials. Spawning was hastened using eyestalk ablations; however, this may not be required in commercialscale mud crab seed production. Primary spawning produced an average of 2.4 million hatched larvae, whereas secondary spawning produced 0.4 million. About 10 days elapsed between spawning and hatching and 30 days between hatching and crablet. Mass mortalities up to 90% were observed between stages zoea 1 and zoea 2 in every trial. The highest survival rate from zoea 1 to crablet was estimated at 0.25%. Most commercial shrimp hatcheries in Korea are equipped with almost all necessary facilities and could be converted easily to mud crab hatcheries, able to run three to four times per year using hatchery technologies developed for blue crabs and Chinese mitten crabs.

Modeling of high energy laser heating and ignition of high explosives (고출력 레이저에 의한 가열과 폭약의 점화 모델링)

  • Lee, Kyung-Cheol;Kim, Ki-Hong;Yoh, Jai-Ick
    • Journal of the Korean Society of Propulsion Engineers
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    • v.12 no.3
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    • pp.1-8
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    • 2008
  • We present a model for simulating high energy laser heating of metal for ignition of energetic materials. The model considers effect of ablation of steel plate with long laser pulses and continuous lasers of several kilowatts and the thermal response of well-characterized high explosives for ignition. Since there is enough time for the thermal wave to propagate into the target and to create a region of hot spot in the high explosives, electron thermal diffusion of ultra-short (femto- and pico-second) lasing is ignored; instead, heat diffusion of absorbed laser energy in the solid target is modeled with thermal decomposition kinetic models of high explosives. Numerically simulated pulsed-laser heating of solid target and thermal explosion of RDX, TATB, and HMX are compared to experimental results. The experimental and numerical results are in good agreement.

Effects of Transcription Factor AP2γ on Gene Expression of Desmosome Components in Mouse Embryos

  • Chung, Hak-Jae;Jeong, Jiyeon;Jeong, Yelin;Choi, Inchul
    • Reproductive and Developmental Biology
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    • v.40 no.2
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    • pp.23-26
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    • 2016
  • Transcription factor called activating enhancer binding protein 2C (AP2-gamma) is found in a variety of species and expressed from oocyte stage onwards, particularly restricted to the trophectoderm. Recent studies demonstrated that ablation of Tfap2c led to failure of tight junction biogenesis, particularly the knock-down embryos of Tfap2c did not form cavity from morula to blastocyst in mouse and pig. We speculated that the Tfa2pc may also be involved in desmosome biogenesis because blastocoel formation is coincident with the establishment of desmosome. To determine this, we depleted Tfap2c injecting siRNA into one-cell zygote and analysed the expression levels of genes that are required for desmosome complex such as PkP2, Pkp3, Dsc2, and Dsg2. We found only Pkp3 was up-regulated in the knockdowned morula embryos. Interestingly, upstream region of Pkp3 had putative Tfap2c binding sites. In conclusion, our results suggest that Tfap2c is not a crucial factor but somehow it might be involved in desmosome biogenesis directly or indirectly via Pkp3.

Ceruminous Gland Adenocarcinoma in a Maltese Dog (말티즈견에서의 귀지선암종 1례)

  • Ahn, Se-Joon;An, Ji-Young;Lim, Soo-Ji;Jeong, Seong-Mok;Park, Seong-Jun;Cho, Sung-Whan;Choi, Ho-Jung;Lee, Young-Won
    • Journal of Veterinary Clinics
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    • v.26 no.5
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    • pp.499-503
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    • 2009
  • A 12-year-old, female, Maltese dog was presented with otic signs, such as pruritus and malordorous discharge. Medical treatment of otitis externa had been carried out for several months at primary animal hospital. Radiography, ultrasonography (US), computed tomography (CT), fine needle aspiration (FNA), and histopathological examination were performed for the diagnosis of ceruminous gland adenocarcinoma. Total ear canal ablation and lateral bulla osteotomy were performed for excision of the tumor. Facial nerve paralysis developed after surgery is getting better through the acupuncture therapy.