• 한국전자파학회논문지
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• 제27권1호
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• pp.60-68
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• 2016

본 논문에서는 6~18 GHz 대역 7-bit 28 dB 가변 신호 감쇠기의 설계 및 측정결과에 대하여 기술하였다. 기존의 switched-T 감쇠기에 칩 사이즈를 최소화하기 위해 인덕터를 사용하지 않았고, 보상용 병렬 커패시터를 추가하여 참조 상태 (reference state)와 감쇠 상태간의 위상 변화를 최소화하였다. 설계된 감쇠기는 $0.18{\mu}m$ CMOS 공정을 이용하여 제작하였다. 측정된 감쇠기의 해상도와 전체 감쇠 범위는 각각 0.22 dB 및 28 dB이다. 6~18 GHz의 동작 주파수에서 RMS 감쇠 오차는 0.26 dB 이하, 위상 오차는 $3.2^{\circ}$ 이하로 측정되었으며, 참조상태 손실은 12.4 dB 이하이다. 전체 주파수 범위와 감쇠상태에서 입출력 반사손실은 9.4 dB 이상이다. 패드를 포함하지 않은 칩 면적은 $0.11mm^2$이다.

• 한국가스학회지
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• 제10권2호
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• pp.22-26
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• 2006

본 연구에서는 하루 50 kg의 DME를 생산하기 위한 파일럿 플랜트를 Aspen Plus를 사용하여 전산모사 하였다. 전체 DME 분리공정의 모델링을 위하여 NRTL 액체 활동도계수 모델식을 사용하였으며 light 가스 성분의 용매의 용해도 추산을 위해서 Henry의 법칙을 사용하였으며 기상의 비이상성을 계산하기 위해서 SRK 상태방정식 모델식을 사용하였다. 전산모사 결과로 DME 분리탑의 중간 제품으로써 98 wt% 이상의 순도를 갖는 DME를 얻을 수 있었다.

• Asian-Australasian Journal of Animal Sciences
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• 제26권1호
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• pp.97-107
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• 2013

The aim of this study was to establish relationships between chemical and physical parameters of wheat with performance and digestibilities of feed components in broiler chickens fed on wheat-based diets. Ninety-four wheat samples were selected for inclusion in four bird trials. Birds were housed in individual wire metabolism cages from 7 to 28 d and offered water and feed ad libitum. Dry matter intake (DMI), liveweight gain (LWG) and gain:feed were measured weekly. A balance collection was carried out from 14 to 21 d for determination of apparent metabolizable energy (AME), ME:gain, dry matter retention, oil and neutral detergent fibre (NDF) digestibility. At 28 d the birds were humanely killed, the contents of the jejunum removed for determination of in vivo viscosity and the contents of the ileum removed for determination of ileal dry matter, starch and protein digestibility. When wheat parameters were correlated with bird performance data, it was found that specific weight was not significantly (p>0.05) related to bird performance. Bird DMI, LWG and gain:feed were best correlated (p<0.05) with the rate of starch digestion, although the coefficients of correlation (r) were still low (0.246 to 0.523). A negative relationship (p<0.01) between AME and total (r = -0.432) and soluble (r = -0.304) non starch polysaccharide (NSP) was observed in this study. Thousand grain weight (TG) was positively correlated with DMI (r = 0.299), LWG (r = 0.343) and gain:feed (r = 0.371). When establishing multiple regression relationships, correlation coefficients greater than 0.8 were achieved for DMI, LWG, gain:feed and ileal crude protein digestibility. However, the economics involved in determining the parameters involved in the regressions make the process impractical.

• 천문학회보
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• 제39권2호
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• pp.80.2-80.2
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• 2014

We present the results of high resolution (R>35,000) optical spectroscopic monitoring observations of a new FU Orionis-like young stellar object, HBC 722. We observed HBC 722 with the Bohyunsan Optical Echelle Spectrograph (BOES) and Hobby-Eberly Telescope (HET) since November 26, 2010. HBC 722 is the FU Orionis-like object best characterized for the pre-outburst phase, and it provides the first opportunity to profile the burst phase of accretion across all wavelengths. We detected a number of lines such as $H{\alpha}$, $H{\beta}$, Fe II ${\lambda}$ 5018, Mg I ${\lambda}$ 5183, Na I D doublets, and metallic photospheric lines. In this work, we focus on the time variations of those spectral lines to understand the accretion process of HBC 722.

• 센서학회지
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• 제30권4호
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• pp.250-254
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• 2021

A highly sensitive and selective non-dispersive infrared (NDIR) carbon dioxide gas sensor requires achieving high transmittance and narrow full width at half maximum (FWHM), which depends on the interface of the optical filter for precise measurement of carbon dioxide concentration. This paper presents the design, simulation, and fabrication of a Fabry-Perot filter based on a distributed Bragg reflector (DBR) for a low-cost NDIR carbon dioxide sensor. The Fabry-Perot filter consists of upper and lower DBR pairs, which comprise multilayered stacks of alternating high- and low-index thin films, and a cavity layer for the resonance of incident light. As the number of DBR pairs inside the reflector increases, the FWHM of the transmitted light becomes narrower, but the transmittance of light decreases substantially. Therefore, it is essential to analyze the relationship between the FWHM and transmittance according to the number of DBR pairs. The DBR is made of silicon and silicon dioxide by RF magnetron sputtering on a glass wafer. After the optimal conditions based on simulation results were realized, the DBR exhibited a light transmittance of 38.5% at 4.26 ㎛ and an FWHM of 158 nm. The improved results substantiate the advantages of the low-cost and minimized process compared to expensive commercial filters.

• Asian Pacific Journal of Cancer Prevention
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• 제15권14호
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• pp.5545-5550
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• 2014

Background: Human biological materials from cancer patients are linked directly with public health issues in medical science research as foundational resources so securing "human biological material" is truly important in bio-industry. However, because South Korea's national R and D project lacks a proper managing system for establishing a national standard for the outputs of certain processes, high-value added human biological material produced by the national R and D project could be lost or neglected. As a result, it is necessary to develop a managing process, which can be started by establishing operating guidelines to handle the output of human biological materials. Materials and Methods: The current law and regulations related to submitting research outcome resources was reviewed, and the process of data 'acquisition' and data 'distribution' from the point of view of big data and health 2.0 was examined in order to arrive at a method for switching paradigms to better utilize human biological materials. Results: For the deposit of biological research resources, the original process was modified and a standard process with relative forms was developed. With deposit forms, research information, researchers, and deposit type are submitted. The checklist's 26 items are provided for publishing. This is a checklist of items that should be addressed in deposit reports. Lastly, XML-based deposit procedure forms were designed and developed to collect data in a structured form, to help researchers distribute their data in an electronic way. Conclusions: Through guidelines included with the plan for profit sharing between depositor and user it is possible to manage the material effectively and safely, so high-quality human biological material can be supplied and utilized by researchers from universities, industry and institutes. Furthermore, this will improve national competitiveness by leading to development in the national bio-science industry.

• 열처리공학회지
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• 제26권4호
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• pp.185-190
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• 2013

Influence of solution treatment (T4) and peak-aging (T6) on damping capacity was investigated in permanent-mold cast Mg-3%Nd alloy. In as-cast state, the microstructure was characterized by eutectic $Mg_{12}Nd$ intermetallic phase network in the intergranular region. T4 treatment resulted in a dissolution of the eutectic particles, but small amount of the particles still remained in the microstructure. After T6 treatment, nano-sized ${\beta}^{\prime}(Mg_{12}Nd)$ particles were precipitated within the matrix. T4 microstructure showed higher damping capacity than as-cast and T6 ones. In view of the microstructural features, this may well be associated with the dissolution of second-phase particles which play a role in pinning the dislocations acting as a damping source.

• 한국분무공학회지
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• 제10권4호
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• pp.26-31
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• 2005

Today, the research to examine a fact that interaction between the air and the fluid free surface affects the steady state flow and air. We proved the interaction between vortex pairs and free surface on each condition that is created by the end of delta wings. Another purpose of this study is to investigate the effect of surface active material which call change the surface tension and we must consider when we refer to turbulent flow on surface tension. Therefore, this research examined the growth process of vortex pairs on condition of clean, contaminated free surface and wall after we made vortex pairs through counter rotating flaps. The results of this study suggest that vortex pairs in clean free surface rise safely but the vortex pairs in contaminated free surface and rigid, no slip is made secondary vortex or rebounding. However the secondary vortex in rigid, no slip is stronger than before. and we can find the vortex shape which roll up more completely. However, these will disappear by the effect of wall.

• 대한환경공학회지
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• 제33권3호
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• pp.149-156
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• 2011

수중에서 E. coli 소독을 위한 전기-UV-초음파 복합 공정에 대해 실험계획법과 반응표면분석법(RSM)을 적용하였다. 2차반응표면 모형식을 추정할 수 있는 Box-Behnken법을 이용하여 전기-UV-초음파 복합 공정의 소독 반응에서 전기분해($X_1$), UV ($X_2$), 및 초음파 공정($X_3$)의 전력을 독립변수로 선정하여 수학적으로 모형화하였다. 소독 후 잔류 E. coli 수와 독립변수 사이의 실험에서 독립변수에 대해 다음의 모형식이 얻어졌다. 잔류 E. coli number (Ln CFU) = 23.69 - 3.75 Electrolysis - 0.67 UV - 0.26 Ultrasonic - 0.16 Electrolysis UV + 0.05 Electrolysis Ultrasonic + 0.27 $Electrolysis^2$ + 0.14 $UV^2$ - 0.01 $Ultrasonic^2$). 예측된 모형식은 실험 자료와 잘 일치하였다($R^2$ = 0.983). 2차원 등고선도와 3차원 반응표면도가 잔류 E. coli 수에 대한 최적 범위를 구하기 위하여 사용되었다. Design-Expert 소프트웨어의 '수치 최적화'를 이용하여 잔류 E. coli 수에 대한 최적 값을 찾은 결과 1.47 Ln CFU/L이었고, 최적 조건은 전기분해 6.94 W, UV 6.72 W 및 초음파 공정 14.23 W로 나타났다. 본 연구는 반응표면분석법이 복합 소독 공정에서 잔류 E. coli 수를 최소화하고 운전 조건을 최적화하기 위한 적절한 방법 중의 하나라는 것을 보여주었다.

• 한국보건간호학회지
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• 제26권1호
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• pp.147-157
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• 2012

Purpose: The purpose of this study was to identify the related factors of change affecting the stages of change for exercise, on the assumption that there are various stages of change in the exercise behavior of women in nursing college. Methods: The subjects were 496 female college students in D city. The research instruments were stages of change for exercise behavior, the process of change, decisional balance, and self-efficacy. The dates were analyzed by descriptive statistics, ANOVA, and stepwise multiple regression using the SPSS 18.0 program. Results: The distribution of the subjects across the stages was: pre-contemplation, 17.7%; contemplation, 58.7%; preparation, 19.0%; action, 2.8%; maintenance, 1.8%. Analysis of variance showed that cognitive process (F=17.26, p<0.01), behavioral process (F=27.05, p<0.01), the pros of decisional-balance (F=7.07, p<0.01), the cons of decision-balance (F=5.82, p<0.01), and self efficacy (F=17.79, p<0.01) were significantly associated with the change of exercise behavior stages. The related factors of change affecting the change of exercise behavior stage were the cons of decision-making, counter conditioning, self re-evaluation, and body mass index, including 28.4% R-square. Conclusion: The transtheoretical model would be applicable to explain the exercise behavior of some women in nursing college. So, this study will be useful information for developing effective exercise behavior programs considering female students' stages of change.