• 스마트미디어저널
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• 제4권4호
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• pp.47-55
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• 2015

최근 ICT 분야의 컴퓨팅 패러다임의 변화와 다양한 서비스를 지원하기 위한 VoIP 기술이 재조명 받고 있다. 본 논문에서는 Secured mobile VoIP 기반의 음성 서비스를 지원하기 위한 경량 가상화 기술인 Docker를 이용하여 소프트웨어 PBX인 오픈소스 Asterisk와 하드웨어 플랫폼, 그리고 모바일 단말기간의 시스템들을 설계 및 구현하였다. 그리고 이를 기반으로 네트워크 트래픽의 지연 테스트와 음성 보안 테스트를 글로벌 실환경에서 실증 테스트를 통해 검증하였다.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제54권2호
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• pp.94-100
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• 2005

Korea Electrotechnology Research Institute(KERI) has successfully developed a 100hp-1800rpm-class high temperature superconducting(HTS) motor with high efficiency under partnership with Doosan Heavy Industries & Construction Co. Ltd. This motor has a HTS field winding and an air-cooled stator. The advantages of HTS motor can be represented by a reduction of 50% in both losses and size compared to conventional motors of the same rating. The cooling system is based on the heat transfer mechanism of the thermosyphon by using GM cryocooler as cooling source. The cold head is in contact with the condenser of a Ne-filled thermosyphon. Independently, the rotor assembly was tested at the stationary state and combined with stator. The HTS field winding could be cooled into below 30K. Test of open-circuit characteristics(OCC) and short-circuit characteristics(SCC) and load test with resistive load bank were conducted in generator mode. Also, load tests in motor mode driven by inverter were finished at KERI. Maximum operating current of field winding at 30K was 120A. From OCC and SCC test results synchronous inductance and synchronous reactance were 2.4mH, 0.49pu, respectively. Efficiency of this HTS machine was 93.3% in full load(100hp) test. This paper will present design, construction. and experimental test results of the 100hp HTS machine.

• Biomolecules & Therapeutics
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• 제30권4호
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• pp.334-339
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• 2022

Peroxiredoxin 6 (PRDX6) is a bifunctional protein with both glutathione peroxidase and calcium-independent phospholipase activity. Recently, we reported that PRDX6 plays an important role in dopaminergic neurodegeneration in Parkinson's disease. However, the relationship between PRDX6 function and emotional behavior remains elusive. In the present study, we examined depression- and anxiety-like behaviors in PRDX6-overexpressing transgenic (PRDX6-Tg) mice using the forced swim test, tail suspension test, open field paradigm, and elevated plus-maze. PRDX6-Tg mice exhibited depression-like behaviors and low anxiety. In particular, female PRDX6-Tg mice exhibited anxiolytic behavior in the open field test. Furthermore, the serotonin content in the cortex and 5-hydroxytryptophan-induced head twitch response were both reduced in PRDX6-Tg mice. Interestingly, levels of dopa decarboxylase expression in the cortex were decreased in male PRDX6-Tg mice but not in female mice. Our findings provide novel insights into the role of PRDX6 in 5-HT synthesis and suggest that PRDX6 overexpression can induce depression-like behaviors via downregulation of the serotonergic neuronal system.

• Journal of Magnetics
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• 제18권2호
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• pp.130-134
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• 2013

Most electrical machines like motor, generator and transformer are symmetric in terms of magnetic field distribution and mechanical structure. In order to analyze these problems effectively, many coupling techniques have been introduced. This paper deals with a coupling scheme for open boundary problem of symmetric and periodic structure. It couples an analytical solution of Fourier series expansion with the standard finite element method. The analytical solution is derived for the magnetic field in the outside of the boundary, and the finite element method is for the magnetic field in the inside with source current and magnetic materials. The main advantage of the proposed method is that it retains sparsity and symmetry of system matrix like the standard FEM and it can also be easily applied to symmetric and periodic problems. Also, unknowns of finite elements at the boundary are coupled with Fourier series coefficients. The boundary conditions are used to derive a coupled system equation expressed in matrix form. The proposed algorithm is validated using a test model of a bush bar for the power supply. And the each result is compared with analytical solution respectively.

• 대한조선학회논문집
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• 제54권3호
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• pp.215-226
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• 2017

This paper presents numerical results of the performance of a marin propeller in cavitating and non-cavitating flow conditions. The geometry and experimental validation data of the propeller are provided in Potsdam Propeller Test Case(PPTC) in the framework of the second International Symposium on Marine Propulsors 2011(SMP'11) workshop. The PPTC includes open water tests, velocity field measurements and cavitation tests. The present numerical analysis was carried out by using the Reynolds averaged Navier-Stokes(RANS) method on a wall-resolved grid ensuring a y+=1, where the SST k-${\omega}$ model was mainly used for turbulence closure. The influence of the turbulence model was investigated in the prediction of the wake field under a non-cavitating flow condition. The propeller tip vortex flows in both cavitating and non-cavitating conditions were captured through adaptation of additional grids. For the cavitation flows at three operation points, Schnerr-Sauer's cavitation model was used with a Volume-Of Fluid(VOF) approach to capture the two-phase flows. The present numerical results for the propeller wake and cavitation predictions including the open water performance showed a qualitatively reasonable agreement with the model test results.

• 한국응용곤충학회지
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• 제62권4호
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• pp.245-253
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• 2023

대량유살 기술을 통한 총채벌레 방제 기술이 시설 고추재배지를 중심으로 개발되었다. 이 기술의 핵심 요인은 효과적 유인제 개발에 있다. 집합페로몬에 의존하였던 유인전략은 노지 재배지에서는 뚜렷한 효과를 보이지 않았다. 따라서 본 연구는 노지 고추재배지에서 총채벌레의 대량 유살을 위해 새로운 유인물질의 추가가 필요하였다. 또한 노지재배지에서 집합페로몬의 유인력 감소 원인을 규명할 필요가 있었다. 새로운 유인물질로서 methyl isonicotinate (MIN)이 제시되었고, 이 물질이 실내 유인행동분석을 통해 총채벌레에 대한 자체 유인력은 물론이고 집합페로몬과 협력효과를 보였다. 이를 바탕으로 집합페로몬과 혼합물 형태로 노지 고추재배지에서 분석한 결과 총채벌레의 포획밀도를 증가시켰다. 특히 이러한 증가는 꽃노랑총채벌레(Frankliniella occidentalis)에서 뚜렷하게 나타났다. 유인트랩에 집합페로몬의 함량 증가는 노지 고추재배지에서 꽃노랑총채벌레는 물론이고 다른 총채벌레류의 포획밀도를 뚜렷하게 증가시켰다. 본 연구는 집합페로몬 유인력이 시설재배지와 노지재배지 사이에서 차이가 있으며, 노지 재배지의 경우 효과적 유인력을 발휘하기 위해서는 더욱 많은 집합페로몬 함량을 요구한다는 것을 밝혔다. 또한 본 연구는 집합페로몬에 MIN을 추가하여 꽃노랑총채벌레에 대한 고효율 유인제를 개발할 수 있는 기술을 제시한다.

• 비파괴검사학회지
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• 제27권6호
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• pp.563-575
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• 2007

This contribution contained the classical work of an open-hole tensile plate to demonstrate the performance of grating shearography and to compare with the results obtained by other full-field measurement techniques, The isotropic plate with an open-hole has often appeared in the previous contributions introducing novel full-field method and system. Grating shearography directly provided six quantitative measurands about the specimen's surface kinematics by using a single measurement set: three in-plane strains, in plane rotation, and two out-of-plane slopes. The quasi-plane wavefront of grating metrology led to high signal-to-noise ratio (SNR) and thus neither fitting nor filtering was applied, and the small shearing distance of $101{\mu}m$ could be used. The small shearing distance provided the outstanding spatial resolution of $80{\mu}m$ and sensitivity appropriate for experimental mechanics. Finally, the grating shearography enabled the visualization of the complex surface deformation around the hole and also detected parasitic flexions of the specimen in the micrometer regime during the tensile test.

• Corrosion Science and Technology
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• 제7권1호
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• pp.61-67
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• 2008

In this paper, electrochemical and microstructural characteristics of nickel-plated Alloy 600 were investigated in order to identify the performance of electroless Ni-plating on Alloy 600 in high-temperature aqueous condition with the comparison of electrolytic nickel-plating. For high temperature corrosion test of nickel-plated Alloy 600, specimens were exposed for 770 hours to typical PWR primary water condition. During the test, open circuit potentials (OCP's) of all specimens were measured using a reference electrode. Also, resistance to flow accelerated corrosion (FAC) test was examined in order to check the durability of plated layers in high-velocity flow environment at high temperature. After exposures to high flow rate aqueous condition, the integrity of surfaces was confirmed by using both scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). For the field application, a remote process for electroless nickel-plating was demonstrated using a plate specimen with narrow gap on a laboratory scale. Finally, a practical seal design was suggested for more convenient application.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2002년도 봄 학술발표회 논문집
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• pp.589-596
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• 2002

In this study, static pile load tests with load transfer measurement were accomplished in the field. Yield pile capacity (or ultimate pile capacity) determined by load-settlement-time relationship was determined and axial load transfer behavior was analyzed. In the test for the four test piles were behaved as end bearing pile but ratios of skin friction to total pile capacity were 27%∼33%.

• 생명과학회지
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• 제30권4호
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• pp.321-330
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• 2020

본 연구의 목표는 CuCl₂가 지브라피시에 미치는 영향을 조사하는 것이다. CuCl₂에 대한 지브라피시의 반수치사농도를 조사하기 위하여 각기 다른 시간에 따른 농도를 설정하여 노출시켰다. 본 연구에서는 스트레스 반응의 증가를 보기 위하여 whole-body cortisol level 측정과 행동약리학적 변화를 측정하기 위해서 open field test와 novel tank test를 실시하였다. Whole-body cortisol의 sample을 수집하거나 행동실험을 실시하기 전에 CuCl₂ 또는 vehicle을 1시간 동안 처리하였다. CuCl₂의 반수치사농도는 24시간, 48시간, 96시간에서 각각 30.3, 25.3, 14.8 ㎍/l으로 측정되었다. CuCl₂에 노출된 지브라피시의 novel tank test의 결과는 총 이동거리, 움직이는 시간 그리고 속도는 유의성이 있게 감소한 반면, turn angle은 최고농도에서 유의성이 있게 증가하였다(p<0.05). 다른 행동실험인 open field test의 결과에서도 총 이동거리, 움직이는 시간 속도가 CuCl₂의 노출에 의해서 감소하였으며, turn angle과 meandering이 유의하게 증가하였다(p<0.05). CuCl₂에 노출된 지브라피시의 whole-body cortisol은 1.5 or 15 ㎍/l의 농도에서는 유의하게 증가하였으나, 150 ㎍/l의 농도에서는 유의성 있는 변화를 발견하지 못하였다(p<0.05). 본 연구의 결과는 CuCl₂의 노출이 지브라피시에서 치사율 증가, 행동 및 내분비의 변화 등을 포함하는 독성 반응을 야기하는 것을 나타낸다.