• 대한치과의사협회지
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• 제20권7호통권158호
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• pp.625-630
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• 1982

The author observed the behavior of inflammatory cells in the primary intension of incisional wound on the Albino rat palate. The superficial wounds (0.5mm depth) were made anteroposterior lineally by surgical knife. They were sacrified on 4, 8, 12, 16, 24, 48, 72 and 120 hr after wounding. The specimens were fixed in 2.5% glutaraldehyde in 0.1 M cacodylate buffer and 1% osmic acid in 0.1M cacodylate buffer, and embeddd in Epon 812. Ultrathin sections were obtained by LKB 8800, and stained with uranyl acetate/lead citrate, and observed with Corynth 500 EM.

• Journal of the Korean Statistical Society
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• 제26권3호
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• pp.333-354
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• 1997

Computational algorithms to calculate M-estimators and rank estimators of regression parameters from left-truncated and right-censored data are developed herein. In the case of M-estimators, new statistical methods are also introduced to incorporate leverage assements and concomitant scale estimation in the presence of left truncation and right censoring on the observed response. Furthermore, graphical methods to examine the residuals from these data are presented. Two real data sets are used for illustration.

• 한국항공우주학회지
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• 제50권2호
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• pp.119-125
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• 2022

본 논문에서는 500kg급 중형위성에 탑재를 목표로 개발한 C-밴드 영상 레이다용 파형발생수신모듈의 설계, 제작 및 시험 결과를 제시한다. 파형발생수신모듈은 약 500km의 고도에서 해상도 10m 기준 120km의 관측 폭을 만족할 수 있도록 50MHz 대역의 2개 주파수를 동시 운용하는 이중주파수 스캔 방식을 적용할 수 있도록 설계하였다. 제작된 파형발생수신모듈은 우주환경을 고려하여 방사성 내성이 고려된 RTG4 FPGA를 적용하였으며, 병렬 직접합성방식(PDDS)을 적용하여 메모리 맵 방식 대비 작은 메모리 용량으로 첩 신호를 생성할 수 있도록 구현하였다. 시험결과 주파수 순도가 높은 첩 파형을 안정적으로 생성하였으며, 수신 신호에 대해 디지털 하향 변환 후 확인 결과 목표한 IRF (Impulse Response Function) 성능을 확인할 수 있었다.

• 한국환경과학회지
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• 제17권2호
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• pp.203-210
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• 2008

The batch tests were performed to determine the ratio of Fenton reagent on diesel contaminated soil. The objective of a column test was to determine and optimize the hydrogen peroxide requirements for the remediation of a soil contaminated with diesel fuel. The batch test were done on 5 g diesel contaminated soil containing hydrogen peroxide (35%) and Iron (II) sulfate. The $H_2O_2(g):Fe^{2+}(g)$ ratio varied 1:0, 30:1, 15:1, 5:1, 1:1, with contact reaction time 120min. Initial diesel concentration were 2,000 mg/kg, 5,000 mg/kg, and 10,000 mg/kg. Average diesel removal from the contaminated soil is 97% after 2hrs. Results of this study showed possible application of without addition of iron source. In column test, treatment of a diesel-contaminated soil (initial diesel concentration: 2,000 mg/kg, 5,000 mg/kg, and 10,000 mg/kg) with hydrogen peroxide (35%) only was containing natural-occurring minerals. The time required for the column test was approximately 90min, 180min, 270min; column length was 5 em, 10 em, and 15 em. The most effective stoichiometry (final diesel cone.: $200{\sim}300mg/kg$) of 0.2 g peroxide consumed/mg diesel degraded. Further investigation is required to identify the effect of soil organic matter and soil mineral.

• Nuclear Engineering and Technology
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• 제55권10호
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• pp.3591-3598
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• 2023

Photoneutron background spectroscopy observations at linac are essential for directing accelerator shielding and subtracting background signals. Therefore, we constructed a Bonner Sphere Spectrometer (BSS) system based on an array of BF₃ gas proportional counter tubes. Initially, the response of the BSS system was simulated using the MCNP5 code. Next, the response of the system was calibrated by using neutrons with energies of 2.86 MeV and 14.84 MeV. Then, the system was employed to measure the spectrum of the ²⁴¹Am-Be neutron source, and the results were unfolded by using the Gravel and EM algorithms. Using the validated system, the undesirable neutron spectrum of the 120 MeV electron linac was finally measured and acquired. In addition, it is demonstrated that the equivalent undesirable neutron dose at a distance of 3.2 m from the linac is 19.7 mSv/h. The results measured by the above methods could provide guidance for linac-related research.

• Journal of Welding and Joining
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• 제29권4호
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• pp.85-92
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• 2011

Microstructures and tensile properties in arc brazed joints of ferritic stainless steel, 429EM using Cu-8.6%Al insert metal was investigated as function of brazing current. The brazing speed was fixed at 800mm/min and brazing current varied in the range of 80A to 120A. The initial phase of filler metal was Cu single phase. However, the insert metal structures of brazed joints was composed of Cu matrix and intermetallic compound such as ${\gamma}_1(Al_4Cu_9)$, and flower-shape Fe-Cr. The fraction of ${\gamma}_1(Al_4Cu_9)$ phase was similar with 80A and 100A brazing currents while that of brazed with 120A was decreased. On the other hand, the fraction of Fe-Cr phase increased with increasing of the brazing current. A reaction layer at the base metal/insert metal interface was observed and this reaction layer was thickened with increasing of the brazing current. In the brazed joints with the current lower than 100A, crack was grew up along the interface which was perpendicular to the tensile stress, and then, passed through the insert metal in the final stage of fracture. As the brazing current increased to 120A, fracture occurred at the base metal.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 추계학술대회 논문집
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• pp.1090-1095
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• 2008

Track geometry changes by traffic loads. The bigger the changes are, the worse the riding comfort and running stability of train. This is so-called track irregularity and is the most important quality parameters of ballasted track. To objectively assess track irregularity, track geometry should be able to be measured. Practically, railway companies use moving chord method, which determine versine values via a chord. The versine is the vertical distance to curve measured in the middle of the chord. This type of method measures only versine of track irregularity curve by transfer function from the characteristics of measuring device. In this report, review the characteristics of two types of measuring tools by comparing the measurements. The one is GRP-1000 system, optical surveying system with Total station and lazar prism trolley. This calculates track geometry by surveying absolute coordinates of two points each on both rail heads. The other is EM-120, measures versine with 10m of symmetrical chord length.

• 한국항공우주학회지
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• 제33권11호
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• pp.115-120
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• 2005

본 논문에서는 과학기술위성 2호 대용량 메모리 유닛(Mass Memory Unit, MMU)의 시험모델(Engineering Model, EM)을 개발하고 기능 및 성능 시험한 결과를 제시하였다. 성능 구현에 필요한 로직들을 별도의 전용 칩들을 사용하지 않고 하나의 FPGA에 구현함으로써 대용량 메모리 유닛을 소형화, 경량화하고 저전력으로 사용할 수 있도록 하였다. 대용량 메모리는 2Gbits SDRAM 모듈을 사용하였으며 파일 시스템을 운용하여 지상국에서의 데이터 관리가 용이 하도록 하였다. 대용량 메모리에서 발생하는 SEU(Single Event Upset)를 극복하기 위해서 RS(207,187) 코드가 소프트웨어로 구현되어 있어서 187바이트당 10바이트의 에러를 복구할 수 있다. 또한 탑재체 데이터의 수신 성능을 검증하기 위해서 시뮬레이터를 제작 하였다.

• Asian Pacific Journal of Cancer Prevention
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• 제16권7호
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• pp.2959-2965
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• 2015

The incidence and mortality rates of breast cancer in Northeast Brazil are increasing and little is known about prevailing reproductive factors contributing to this increase. A case-control study was conducted in a public hospital of Campina Grande, state of $Para{\acute{i}}ba$, including 81 women with diagnosed invasive breast cancer and 162 age matched (${\pm}5years$) controls. Binominal logistic regression analysis was applied to estimate odds ratio (OR) and confidence intervals (CI) of risk factors. In this model, age at menarche ${\leq}12$ (OR=2.120; CI: 1.043-4.308; p=0.038), single parity (OR=3.748; CI: 1.459-9.627; p=0.06) and reproductive period >10 years (OR=3.042; CI: 1.421-6.512; p=0.04) were identified as independent variables that significantly increased breast cancer risk of parous women. Compared to parous women who never practised breastfeeding, total breastfeeding time > 24 months decreased the risk of breast cancer (OR=0.258; CI: 0.084-0.787; p=0.017). The results indicated that modifiable reproductive factors contribute to breast cancer risk in women included in the present study. Women's knowledge about factors such as the protective effect of breastfeeding could reduce the risk of breast cancer.

• 대한전자공학회논문지TC
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• 제45권8호
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• pp.114-120
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• 2008

본 논문에서는 단락 개방 Calibration (SOC) 방법을 이용하여 MIM 구조로 구성된 커패시터의 기생 소자 값들을 추출하였다. Strip line 으로 구성된 short, open, MIM 구조들의 산란 파라미터 행렬들은 전자기 시뮬레이터 및 벡터 네트웍 분석기를 이용하여 측정되었다. 전자기 시뮬레이션들은 3차원 구조 해석에 적합해왔던 유한 유소법 (FEM)을 이용하여 수행되었다. 적층 구조 내부에 형성된 MIM 커패시터의 전자기 영향들은 집중 소자들로 구성된 II 형 등가 회로로 제안되었고, 2 포트 네트웍 해석을 수행함으로써, 측정된 산란 파라미터들과 등가회로 소자들 간의 관계를 보였다. 제안된 SOC 방법을 이용하여 추출된 집중 소자들은 주파수 독립적인 결과를 나타낸다.