• The Korean Journal of Ceramics
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• 제3권1호
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• pp.13-17
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• 1997

It is identified that the diamond films grown o bias-treated (100) silicon showed different surface morphologies and film textures according to the initial applied dc bias voltage at the same growth condition. The highly oriented diamond film (HODF) was successfully grown on -200 V bias-treated silicon substrate in which the heteroepitaxial relation of $(100)_{dimond}//(100)_{si}\; and\; [110]_{diamond}//[110]_{si}$ was identified. On the contrary, the heteroepitaxial relation was considerably disturbed in the samples bias-voltage was a key factor in growing the highly oriented diamond film on (100) silicon substrate. Considering the experimental results, we proposed a new model about heteroepitaxial diamond growth on silicon, in which 9 diamond unit cell are matched with 4 silicon cells and the bond covalency of both atoms is satisfied via the intermediate layer at the interface as well.

• 한국막학회:학술대회논문집
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• 한국막학회 1999년도 The 7th Summer Workshop of the Membrane Society of Korea
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• pp.95-96
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• 1999

The ultrafiltration behavior of dilute colloidal solution containing Si particles has been investigated. The experiments in cross flow mode have been performed at different operating condition by using the membrane with 20 kDa cut-off. The flux decline was due to the development of membrane fouling which was a dynamic process of two distinctive stages. For the high trans-membrane pressure, the pore blocking resistance was dominant at the initial period of filtraion and was followed by the cake resistance. And for the low cross flow velocity, the membrane fouling was governed by the cake filtration model at the initial stage of filtration process. Flux jump was observed temporally during the membrane filtration of mixed feed solution.

• Nuclear Engineering and Technology
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• 제53권5호
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• pp.1602-1611
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• 2021

A varying degree of eccentricity always exists in the initial configuration of a nuclear fuel rod. Its impact on traditional LWR fuel is limited as the radial gap closes relatively early during irradiation. However, the effect of misalignment is expected to be more relevant in rods with highly conductive fuels, large initial gaps and low conductivity filling gases. In this paper, we study similar characteristics in the experimental setup of two fuel disc irradiation campaigns carried out in the OECD Halden Boiling Water Reactor. Using the multi-dimensional fuel performance code OFFBEAT, we combine 2-D axisymmetric and 3-D simulations to investigate the effect of eccentricity on the fuel temperature distribution. At the same time, we illustrate how the advent of modern tools with multi-dimensional capabilities might further improve the design and interpretation of in-pile separate-effect tests and we outline the potential of such an analysis for upcoming experiments.

• Steel and Composite Structures
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• 제44권2호
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• pp.211-224
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• 2022

Multi-objective optimization was conducted to obtain the optimal configuration of a composite sandwich structure with honeycomb-foam hybrid core subjected to underwater shock waves, which can fulfill the demand for light weight and energy efficient design of structures against underwater blast. Effects of structural parameters on the dynamic response of the sandwich structures subjected to underwater shock waves were analyzed numerically, from which the correlations of different parameters to the dynamic response were determined. Multi-objective optimization of the structure subjected to underwater shock waves of which the initial pressure is 30 MPa was conducted based on surrogate modelling method and genetic algorithm. Moreover, optimization results of the sandwich structure subjected to underwater shock waves with different initial pressures were compared. The research can guide the optimal design of composite sandwich structures subjected to underwater shock waves.

• Journal of Yeungnam Medical Science
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• 제40권2호
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• pp.198-201
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• 2023

Invasive sphenoid sinus aspergillosis can mimic Tolosa-Hunt syndrome (THS), leading to frequent misdiagnoses and potentially fatal consequences. We report a case of invasive sphenoid sinus aspergillosis initially misdiagnosed as THS. A 79-year-old man presented with right periorbital pain, ophthalmoplegia, and loss of vision. Initial evaluations including magnetic resonance imaging (MRI), were normal. He was first diagnosed with THS based on clinical features. The disease progressed despite high-dose intravenous steroid treatment, and an enhancing mass-like lesion was found in the right orbital apex, cavernous sinus, and sphenoid sinus on follow-up MRI. Aspergillosis was eventually confirmed by sphenoid sinus biopsy. The patient developed cerebral infarction and finally died despite being treated with amphotericin B. Given that invasive sphenoid sinus aspergillosis may initially resemble THS, high suspicion and rapid histological examination are important for diagnosis.

• 한국군사과학기술학회지
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• 제27권4호
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• pp.474-484
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• 2024

Reinforcement learning, which are also studied in the field of defense, face the problem of sample efficiency, which requires a large amount of data to train. Transfer learning has been introduced to address this problem, but its effectiveness is sometimes marginal because the model does not effectively leverage prior knowledge. In this study, we propose a stochastic initial state randomization(SISR) method to enable robust knowledge transfer that promote generalized and sufficient knowledge transfer. We developed a simulation environment involving a cooperative robot transportation task. Experimental results show that successful tasks are achieved when SISR is applied, while tasks fail when SISR is not applied. We also analyzed how the amount of state information collected by the agents changes with the application of SISR.

• Tuberculosis and Respiratory Diseases
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• 제55권2호
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• pp.154-164
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• 2003

연구배경 : 1990년대 초반까지 민간 병의원에서의 폐결핵환자 치료효율은 보건소에 비해 낮았다. 보건소에 비해 민간 병의원에서 치료받는 결핵환자의 비율이 최근 계속 증가하고 있지만, 민간부문에서 치료 받는 환자들의 특성과 치료효율은 정확히 파악되지 못하고 있다. 본 연구는 서울에 소재한 한 민간 종합병원에서 최근 진단되고 치료한 폐결핵환자의 특성과 치료효율을 조사하고자 하였다. 방 법 : 2000년 8월 1일부터 2001년 1월 31일까지 6개월간 삼성서울병원에서 진단되어 관할 보건소로 신고된 232명의 성인 폐결핵 환자를 대상으로 진단 시 연령과 성별, 입원여부, 과거 폐결핵 치료력, 객담 항산균 도발과 배양 검사 결과, 약제감수성검사 결과, 치료약제의 종류 및 치료 기간, 치료 결과 그리고 도말 양성 환자에서의 치료성적 등을 조사하였다. 결 과 : 232명의 폐결핵 환자의 평균 연령은 47세(범위 16-86세)이고 남자 136명(58.6%), 여자 96명(41.4%)이었다. 82명(35.3%)의 환자는 진단 당시 입원치료를 받았고, 13명(5.6%)이 치료 도중 사망하였다. 과거 치료력이 없는 신환이 166명(71.6%), 재발이 32명(13.8%)이었다. 도말 양성 환자가 83명(35.8%), 도말 음성 배양 양성 환자가 27명(11.6%)으로 균 양성 환자가 110명(47.4%)이었다. 47명(20.3%)에서는 객담 검사가 시행되지 않았다. 초치료 환자 188명 중 130명(69.1%)에서 INH, RFP, EMB, PZA가 처방되었고, 21명(11.2%)에서 INH, RFP, EMB가 사용되었다. 전체 폐결핵 환자 232명 중 26명(11.2%)과 도말 양성 환자 83명 중 11명(13.3%)이 치료를 중단하였다. 도말 양성 초치료 환자 68명 중 29명(42.6%)가 완치되었고, 18명(26.5%)은 치료를 종결하였으나 균 음전을 확인할 수 없었다. 결 론 : 민간 병의원에서 진단된 폐결핵 환자의 치료효율을 높이고 치료 중단률을 낮추기 위해서는 폐결핵 환자의 진단과 치료에서 대한 결핵 및 호흡기학회의 진료기준을 충실히 따르려는 보다 적극적인 노력과 함께 우리나라 실정에 맞는 적절한 공공-민간 협력체계의 국가결핵관리모델의 개발이 필요하리라 사료된다.

• 소성∙가공
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• 제29권1호
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• pp.27-36
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• 2020

The Goss texture component of {110}<001> is well known as one of the best texture components to improve the magnetic properties of electrical steel sheets. The small amount of the Goss texture component is obtained at the surface of the steel sheet by shear deformation due to friction between the steel sheet and the roll during conventional symmetric rolling. This study aims to identify a method to obtain high intensity of the Goss texture component not only at the surface but in the whole layer of the steel sheet by shear deformation of asymmetric rolling. Low carbon steel sheets, which have different initial texture, were asymmetrically rolled by about 50%, 70%, and 80%. The pole figures of the top, center, and bottom layers of the initial and asymmetrically rolled low carbon steel sheets were measured by an X-ray diffractometer. Based on the measured pole figures of these samples, the intensities of the main texture components were analyzed for the initial and asymmetrically rolled low carbon steel sheets. As a result, the initial low carbon steel sheet with the γ-fiber component showed a higher intensity of the Goss texture component in the whole layer than the steel sheet with other texture components after asymmetric rolling.

• The Journal of Advanced Prosthodontics
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• 제3권2호
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• pp.76-80
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• 2011

PURPOSE. Implant stability quotient (ISQ) values have been supposed to predict implant stability. However, the relationship between ISQ values and bone-to-implant contact ratio (BIC%) which is one of the predictors of implant stability is still unclear. The aim of the present study was to evaluate initial ISQ values in relation to BIC% using rabbit model. MATERIALS AND METHODS. Four New Zealand white rabbits received a total of 16 implants in their tibia. Immediately after implant placement ISQ values were assessed. The measurements were repeated at the time of sacrifice of the rabbits after 4 weeks. Peri-implant bone regeneration was assessed histomorphometrically by measuring BIC% and bone volume to total volume values (bone volume %). The relationships between ISQ values and the histomorphometric output were assessed, and then, the osseointegration prediction model via the initial ISQ values was processed. RESULTS. Initial ISQ values showed significant correlation with the BIC%. The bone volume % did not show any significant association with the ISQ values. CONCLUSION. In the limitation of this study, resonance frequency analysis is a useful clinical method to predict the BIC% values and examine the implant stability.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 추계학술대회 논문집 Vol.17
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• pp.61-64
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• 2004

In this paper, we investigated the variations of initial fault current limiting instant according to fault angles in the flux-lock type SFCL. The flux-lock type SFCL consists of the coil 1 and the coil 2 that are wound in parallel each other through an iron core. The operation of the flux-lock type SFCL can be divided into the subtractive polarity winding and the additive polarity winding operations according to the winding directions between the coil 1 and coil 2. The subtractive polarity winding operation could be analyzed with three modes. On the other hand, the additive polarity winding operation could be analyzed with five modes. The variations of initial fault current limiting instant in two winding directions were dependent on the fault angles. It was confirmed from experiment that the fault current limiting instant was getting faster and the magnitude of fault current at the initial fault time was getting higher for higher fault angle.