• 한국전기전자재료학회논문지
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• 제13권1호
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• pp.66-74
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• 2000

The structural and electrical characteristics of SBT thin films, fabricated on Pt/Ti/SiO\ulcorner/Si substrates by a pulsed laser deposition(PLD), were investigated to develop ferroelectric thin films for capacitor lay-ers of FRAM. EFfects of target composition on the characteristics of SBT thin films were examined. Target were prepared by mixed oxide method, and composition of Sr/Bi/Ta on SBT was changed to 1/2/2, 1/2.4/2, 1/2.8/2, 0.8/2/2 and 1.2/2/2. SBt thin films were fabricated, as a function of substrate temperature and oxygen pressure, by PLD. The optimized ocndition, to fabricate high quality SBT thin films, was 700 $^{\circ}C$ of substrate temperature, 200 mTorr of oxygen pressure, and 2 J/$\textrm{cm}^2$ of laser energy density. Maximum remnant value(2Pr) of 9.0 $\mu$C/$\textrm{cm}^2$, coercive field value(Ec) of 50 kV/cm, dielectric constant value of 166, and leakage current densities of <10\ulcorner A/$\textrm{cm}^2$ were observed for the films with 1/2/2 composition, which was prepared at the above PLD condition.

• 한국주조공학회지
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• 제31권5호
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• pp.288-292
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• 2011

In order to complement the drawbacks of quartz crucible such as fragile-like break and melt-leakage through open slit nozzle, a new PFC system has been developed using a common graphite crucible and plugging system. The u melt is fed on to the rotating a roll through slit nozzle by self-gravity. The new equipment was designed and manufactured successfully. An effort for optimizing all related parameter has been made. Then using the optimized parameters about 10 meters u foil having very thin thickness, which meets the target thickness of 130 ${\mu}m$ and enough width more than 60 mm could be made. The thickness homogeneity set improved, due to the lower eddy flowing of the melt flow the self-gravity feeding system.

• Journal of electromagnetic engineering and science
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• 제15권1호
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• pp.53-58
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• 2015

For the testing of nonlinear power amplifiers, this paper suggests an approach to design optimized multisine signals that could be substituted for the original modulated signal. In the design of multisines, complex coefficients should be determined to mimic the target signal as much as possible, but very few methods have been adopted as general solutions to the coefficients. Furthermore, no solid method for the phase of coefficients has been proven to show the best resemblance to the original. Therefore, in order to determine the phase of multisine coefficients, a time-domain nonlinear optimization method is suggested. A frequency-domain-method based on the spectral response of the target signal is also suggested for the magnitude of the coefficients. For the verification, multisine signals are designed to emulate the LTE downlink signal of 10 MHz bandwidth and are used to test a nonlinear amplifier at 1.9 GHz. The suggested phase-optimized multisine had a lower normalized error by 0.163 dB when N = 100, and the measurement results showed that the suggested multisine achieved more accurate adjacent-channel leakage ratio (ACLR) estimation by as much as 12 dB compared to that of the conventional iterative method.

• 한국멀티미디어학회논문지
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• 제18권1호
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• pp.42-51
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• 2015

In this paper, we analyze the quality status of Health and Welfare division's standardized log and asses the characteristics of the institutions' logs analysis to establish the criteria to minimize hazards and control the quality of log's institutional details to limit extraction. As a result, extraction condition's proposed development direction to adequately assess and control health and welfare abuses privacy control target log. This improvement over the status and quality of information shared with relation to institutional work of the log quality characteristics is made possible. In addition, quality control and inspection standards were prepared in accordance with the institutional log characteristics. Future research will include performing continuous analysis and improvement activities on the quality of logs with integrated control of sharing personal information and distributing information about logs' quality to proactively target organ. Therefore, we expect that correcting proactive personal information misuse and leakage is possible to achieve.

• 에너지공학
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• 제23권1호
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• pp.40-45
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• 2014

주거시설에서 환기횟수 0.7회 적용은 실내공기질 향상과 거주자의 쾌적성을 높이고자 100세대 이상은 의무적으로 적용하고 있다. 건축물에너지효율등급에서는 환기횟수를 기준으로한 기밀시험을 실시 하여 그결과 값을 효율등급결과치에 반영함으로서 창호주변의 정밀시공을 유도하고 침기로 인해 손실되는 에너지절감을 꾀하고 있다. 건축물엔지효율등급 현장실사 결과 환기횟수가 0.6~0.71까지 나타났으며 그차이가 에너지 절감량에 크게 영향을 미치는 것으로 나타났다. 유럽의 패시브 하우스 기준이 0.6회 이하의 기밀을 요구하고 있고 우리나라도 2017년 패시브하우스, 2025년 제로하우스를 목표로 하고 있어 비주거 건물의 기밀진단의 의무확대와 고기밀 건물에 대한 연구와 시공방법이 시급한 실정이다.

• 한국방재안전학회논문집
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• 제16권3호
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• pp.1-15
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• 2023

본 연구는 복합화력발전소 내 배연탈질 설비에서 원료 및 중간재로 많이 사용되는 암모니아의 연속 누출에 대한 유해 위험 거리 예측 및 정량적 평가를 위한 피해영향 모델링이다. 피해 예측은 사고 영향 평가와 확산모델을 기반으로 암모니아 저장탱크 누출사고의 최적 시나리오를 모델링 하기 위해 변수들의 조업조건을 표준조건으로 하였다. 대상지역인 한국서부발전 태안발전본부의 복합화력발전소는 온도, 습도, 풍속, 대기 안정도, 풍향 등의 계절적 요인에 따른 기상 조건과 지형적 조건을 설정하기에 최적의 조건이며, 시나리오에 따른 모델링 결과가 누출 사고에 대한 특성을 분석하기에 가장 적합하였다. 암모니아 가스는 Gaussian 확산모델을 기반으로 하여 확산에 따른 LOC 별 농도치를 도출하였다. 본 연구를 통한 ALOHA 모델링 결과는 대기 조건의 경우 온도가 높고 안정도가 표준수치 범위이며, 풍속이 낮을수록 암모니아 확산에 의한 인체 피해 영향 정도가 높아지는 것으로 분석되었다.

• 중소기업융합학회논문지
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• 제5권2호
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• pp.1-6
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• 2015

중소기업은 정보시스템의 안전성을 확보하기 위한 조치들이 대기업에 비해 미흡하다. 이런 상황에서 공격자의 공격으로부터 정보유출시 회사이미지, 법적 피해보상 등 어려움을 가지게 된다. 정보시스템을 악성코드을 이용한 정보 유출이나 APT 공격 등 해킹 기법을 알아본다. 특히, APT 공격은 '지능적 지속 위협(Advanced Persistent Threats, 이하 APT)' 공격으로 공격 대상에게 몰래 접근한 뒤 일정 기간 잠복기를 가지고 있다가 공격 대상과 관련한 모든 정보를 오랜 시간 동안 살펴보고, 은밀히 활동하면서 흔적을 남기지 않고 공격 대상의 보안 서비스를 무력화시킨 상태에서 정보를 유출한다. 공격의 흔적이 남지 않도록 로그 등 자신의 흔적을 삭제하면서 공겨하기 때문에 공격 사실을 시간이 지난 후에 인지하므로 그 피해가 크다. 본 논문에서는 공격 방법이나 과정을 알아보고, 공격에 대한 대응방안을 모색한다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2004년도 하계종합학술대회 논문집(2)
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• pp.363-366
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• 2004

PZT thin films were formed by rf-magnetron sputtering on $Pt/Ti/SiO_2/Si$ substrate. Bulk PZT target containing $5\%$ excess PbO was used. They were formed with in-situ process at $650^{\circ}C$ as total thickness of 175 and 250 nm after the depositing of thin PZT films at room temperature, i. e. 2-step Sputtering. It was found that the ferroelectric perovskite phase is formed at $650^{\circ}C$ by XRD and the interface between room temp.-layer and $650^{\circ}C$ -layer is not existent. In the samples undergoing 2-step sputtering the dielectric constant was 600 or more and the leakage current density was $2{\times}10^{-7}A/cm^2$. So, we found that the room temp.-layer on the bottom electrode stabilize the underlaid layers.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제49권4호
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• pp.232-238
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• 2000

PZT thin films(3500 ) have been prepared onto $Pt/Ti/SiO_2/Si$ substrates with a RF magnetron sputtering system using PB1.05(Zr0.52,Ti0.48)O3 ceramic target. We used two-step annealing techniques. As the RTA times and temperatures were increased, crystallization of PZT thin films were enhanced. The ferroelectric characteristics of PZT capacitors fabricated at $700^{\circ}C$ for 60 seconds were like these remanent polarization were $12.1 \muC/cm^2$, coercive field were 110 kV/cm, leakage current density were $4.1\times10-7 A/cm^2,\; \varepsilonr=442,$ and remanent polarization were decreased by 22% after 1010 cycles, respectively.

• 한국유체기계학회 논문집
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• 제1권1호
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• pp.32-40
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• 1998

Aerodynamic performance of a cooling fan of driving motor was enhanced modifying the vane-shroud configuration. Performance of a target model was evaluated to obtain baseline data. The aerodynamic performance and sound pressure level were tested and measured with different numbers of vane of increased length. The tested models show high and stable performance and low values of specific noise level. The long vane-shroud structure induces more stable through flow and decreases the tip leakage flow, which contributes to the increases of performance and efficiency. The sound pressure level increases for the modified model, however, specific noise level decreases.