• 한국항공우주학회지
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• 제47권2호
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• pp.143-152
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• 2019

본 논문에서는 항공용 소형 레이다나 유도 무기 탐색기 등에 적용이 가능한 Ka대역 평면형 능동위상배열 안테나장치를 설계한 내용을 설명하였다. 본 안테나장치는 1000개 급의 복사소자 면배열로 구성하고, 직경 200mm 이내의 크기로 설계하였다. 빔 조향 범위는 ${\pm}55^{\circ}$ 이상 가능하도록 빔 패턴 분석을 통하여 복사 소자 간격을 정의하고 안테나 성능 분석을 수행하였다. RF 구성품 설계와 버짓 검증을 통해 안테나장치의 송신 EIRP는 94.22 dBm, 수신 G/T는 1.68 dB/k 성능으로 요구 규격을 만족할 수 있음을 확인하였다. 송신 EIRP 규격을 만족하기 위해 TRM의 송신 출력은 1.3W 급으로 설계하였고, 수신 G/T 규격을 만족하기 위해 TRM의 수신 잡음 지수를 5dB 이하가 되도록 설계하였다.

• 대한약침학회지
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• 제13권1호
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• pp.63-77
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• 2010

Objectives: The aim of this experiment is to provide an objective differentiation of cultivated ginseng, cultivated wild ginseng, and wild ginseng through component analysis, and to know the change of ginsenoside components in the process for making red ginseng. Methods: Comparative analysis of ginsenoside $Rb_1,\;Rb_2$, Rc, Rd, Re, Rf, $Rg_1,\;Rg_3,\;Rh_1$ and $Rh_2$ from the cultivated ginseng 4 and 6 years, cultivated wild ginseng, and wild ginseng were conducted using High Performance Liquid Chromatography(hereafter HPLC). And the same analyses were conducted in the process of red ginseng. Results: 1. For content comparison of ginsenoside $Rb_1$, Rc, Rd, Rf, $Rg_1$ and $Rh_1$, wild ginseng showed high content, followed cultivated ginseng 4 and 6 years, cultivated wild ginseng showed low content than any other samples. 2. For content comparison of ginsenoside $Rb_2$ and Re, cultivated ginseng 4 years showed high content, followed wild ginseng and cultivated ginseng 6 years, cultivated wild ginseng showed low content than any other samples. 3. For content comparison of ginsenoside $Rg_3$, wild ginseng and cultivated wild ginseng were only showed low content. 4. For content comparison of ginsenoside $Rh_2$, cultivated wild ginseng was only showed low content. 5. In the process of red ginseng, ginsenoside $Rb_1,\;Rb_2$, Rc, Rd, $Rg_3$ and $Rh_1$ were increased, and ginsenoside Re and $Rg_1$ were decreased in cultivated wild ginseng. 6. In the process of red ginseng, ginsenoside $Rg_3$ and $Rh_1$ were increased, and ginsenoside $Rb_2$, Rc, and Re were decreased in cultivated ginseng 4 years. 7. In the process of red ginseng, ginsenoside $Rb_1,\;Rb_2$, Rf and $Rh_1$ were increased, and ginsenoside Rc and Rd were decreased in cultivated ginseng 6 years. Conclusions: Distribution of ginsenoside contents to the cultivated ginseng, cultivated wild ginseng, and wild ginseng was similar and was not showed special characteristics between samples. And the change of ginsenoside to the process of red ginseng, cultivated ginseng and cultivated wild ginseng were showed different aspect.

• Journal of Ginseng Research
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• 제35권1호
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• pp.31-38
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• 2011

In order to distinguish the cultivation area of Panax ginseng, principal component analysis (PCA) using quantitative and qualitative data acquired from HPLC was carried out. A new HPLC method coupled with evaporative light scattering detection (HPLC-ELSD) was developed for the simultaneous quantification of ten major ginsenosides, namely $Rh_1$, $Rg_2$, $Rg_3$, $Rg_1$, Rf, Re, Rd, $Rb_2$, Rc, and $Rb_1$ in the root of P. ginseng C. A. Meyer. Simultaneous separations of these ten ginsenosides were achieved on a carbohydrate analytical column. The mobile phase consisted of acetonitrile-water-isopropanol, and acetonitrile-water-isopropanol using a gradient elution. Distinct differences in qualitative and quantitative characteristics for ginsenosides were found between the ginseng roots produced in two different Korean cultivation areas, Ganghwa and Punggi. The ginsenoside profiles obtained via HPLC analysis were subjected to PCA. PCA score plots using two principal components (PCs) showed good separation for the ginseng roots cultivated in Ganghwa and Punggi. PC1 influenced the separation, capturing 43.6% of the variance, while PC2 affected differentiation, explaining 18.0% of the variance. The highest contribution components were ginsenoside $Rg_3$ for PC1 and ginsenoside Rf for PC2. Particularly, the PCA score plot for the small ginseng roots of six-year old, each of which was light than 147 g fresh weight, showed more distinct discrimination. PC1 influenced the separation between different sample sets, capturing 51.8% of the variance, while PC2 affected differentiation, also explaining 28.0% of the variance. The highest contribution component was ginsenoside Rf for PC1 and ginsenoside $Rg_2$ for PC2. In conclusion, the HPLC-ELSD method using a carbohydrate column allowed for the simultaneous quantification of ten major ginsenosides, and PCA analysis of the ginsenoside peaks shown on the HPLC chromatogram would be a very acceptable strategy for discrimination of the cultivation area of ginseng roots.

• 한국항행학회논문지
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• 제6권3호
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• pp.195-202
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• 2002

최근 이동통신 서비스가 확대됨에 따라 인접 기지국간의 간섭문제가 증가하게 되었으며, 그에 따라 CDMA 시스템의 active IMD뿐만 아니라 PIMD(Passive Inter-Modulation Distortion)에 대한 문제도 시스템 설계 시 고려되어야 한다. 본 논문에서는 RF connector 중 대표적 connector인 7/16" DIN connector를 통하여 동축선에서의 PIMD 발생원인 분석을 위한 다양한 표면조도 및 도금두께, 도금재질을 갖는 어댑터를 설계, 제작하여 PIMD 발생 정도를 분석하였고, PIMD 개선 방안을 제안하였다. 첫째, 대부분의 전류가 통과하는 경로에는 표면조도가 좋은 금속이 전도율이 좋아 유리하며, 둘째, RF 에너지가 충분히 한 매질에서 통과할 수 있도록 최소 $5{\mu}m$ 이상으로 도금을 해야 함을 알 수 있었다. 셋째, 도금 재료의 노화현상 방지를 위해 비열이 높고 전도율이 높은 금속 선택이 필수적이며, 비용절감 면에서는 삼원합금 등 대체 도금 재질 개발이 요구됨을 알 수 있었다. 현재 국내 PIMD 규격인 KTF-150dBc를 만족시키기 위해서는 7/16" DIN connector의 경우 도금재질에 관계없이 표면조도 6S, 도금두께 $5{\mu}m$일 때 KTF의 PIMD 규격을 만족시킬 수 있음을 알 수 있었다.

• 한국식품과학회지
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• 제30권1호
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• pp.199-205
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• 1998

우리의 식생활과 대장암이 밀접한 관계를 가지므로 일반적으로 이용되고 있는 식품과 한방에서 건강식품으로 사용되고 있는 재료들이 장내세균 효소인 ${\beta}-glucuronidase$ 및 tryptophanase 활성에 미치는 효과를 조사하였다. 한방식품 물추출물을 장내세균 배양배지에 첨가하였을때 pH 저하효과, ${\beta}-glucuronidase,{\;}tryptophanase$, 활성억제 효과를 측정한 결과, 대추, 감초는 pH 저하효과 뿐만 아니라 대장암 유발효소인 ${\beta}-glucuronidase$ 및 tryptophanase의 활성을 억제하는 효과도 우수하였다. 한방식품 물추출물의 ${\beta}-glucuronidase$ 및 tryptophanase의 효소를 직접저해하는 효과도 대추, 감초가 우수하였다. 감초, 대추, 수삼, 갈근의 유기용매 분획물의 ${\beta}-glucuronidase$ 및 tryptophanase 생산성 저해효과는 감초의 ether 분획과 대추의 ethylacetate 분획이 가장 우수하게 나타났다. ${\beta}-glucuronidase$ 효소저해활성이 가장 우수한 분획은 대추의 ether 및 ethylacetate 분획이였으며 그 다음이 인삼의 ether 분획과 감초의 ether 분획이였다. Tryptophanase 효소저해활성은 감초의 ether 분획과 대추의 ethylacetate 분획이 우수했다. ${\beta}-Glucuronidase$ 및 tryptophanase 저해효소가 가장 우수한 분획을 silica gel column chromtography로 성분 분획을 하여 6종(Rf=0.98, 0.65, 0.43, 0.34 0.22 0.16)을 분리 하였는데${\beta}-glucuronidase$ 저해효과는 Rf가 0.34인 화합물이 가장 우수 하였으며 tryptophanase 저해효과는 Rf가 0.43인 화합물이 가장 우수 하였다. 대추에는 장내세균 기인성 유해효소를 억제하는 효과가 있는 성분이 함유되어 대장암의 발암물질 생성이 낮아지고 이들 유해효소의 생산성을 억제하는 효과가 우수하게 나타났다 그러므로 대추는 우리 식생활에서 대장암과 같은 성인병 예방에 크게 기여하고 있는 것으로 생각된다.

• 한국마이크로전자및패키징학회:학술대회논문집
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• 한국마이크로전자및패키징학회 2003년도 기술심포지움 논문집
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• pp.145-150
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• 2003

최근에 3 GHz이상의 고주파용 전자부품과 소자의 제조에 낮은 TCR 값과 높은 정밀도를 갖는 박막저항이 사용되고 있다. Ni-Cr 박막저항은 낮은 TCR 값과 저항에 대한 높은 안정성 때문에 저항 물질로 사용되는 가장 일반적인 물질이다. 본 연구에서는 $Ni_{72}Cr_{20}Al_3Mn_4Si(wt\%)$ 첨가된 우수한 저항특성을 갖는 s-type의 Evanohm 합금 타겟과 스퍼터링 장비를 이용하여 박막 저항을 제조하였다. 또한 열처리 조건을 $200^{\circ}C,\;300^{\circ}C,\;400^{\circ}C,\;500^{\circ}C$로 변화시키면서 고주파 박막저항의 미세구조와 전기적 특성을 관찰하여 최상의 열처리 조건을 알아보았다.

• 정보저장시스템학회논문집
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• 제3권3호
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• pp.129-134
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• 2007

Boron nitride (BN) is a highly attractive material for wear resistant applications of mechanical components. BN is super hard and it is the second hardest of all known materials. It also has a high thermal stability, high abrasive wear resistance, and in contrast to diamond, BN does not react with ferrous materials. The motivation of this work is to investigate the tribological properties of BN for potential applications in ultra-precision components for data storage, printing, and other precision devices. In this work, the wear characteristics of BN thin films deposited on DLC or Ti buffer layer with silicon substrate using RF-magnetron sputtering technique were analyzed. Wear tests were conducted by using a pin-on-disk type tester and the wear tracks were measured with a surface profiler. Experimental results showed that wear characteristics were dependent on the sputtering conditions and buffer layer. Particularly, BN coated on DLC layer showed better wear resistant behavior. The range of the wear rates for the BN films tested in this work was about 20 to $100{\mu}m^3$/cycle.

• 한국과학교육학회지
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• 제33권3호
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• pp.569-580
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• 2013

This study examined how a Structured Reading Framework (SRF) is related to improving students' critical thinking ability in an argument-based inquiry approach, called the Science Writing Heuristic (SWH) approach. A total of 75 $8^{th}$ graders participated in the study, with 34 in the control group and 41 in the treatment group. The gains in critical thinking skills were compared between two groups, and relationships among the components of the reading framework and the critical thinking skills were explored at the group level. Result indicates that the treatment group who used the SRF had larger gains in critical thinking scores than control group who used the Original Reading Framework (ORF). In addition, results show that the correlations between Reading Framework (RF) components and critical thinking scores are statistically significant in the treatment group, while no correlations exist in the control group. It appears that using the SRF have an impact on developing students' critical thinking ability by providing a scaffold to assist argumentation practice.

• 한국식품영양학회지
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• 제28권1호
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• pp.1-8
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• 2015

This study was designed to determine the antioxidant activity of solvent fractions of broccoli sprouts grown by controlling the growing environment at the plant factory system. Fractionation was achieved with chloroform, n-hexane, ethyl acetate, butanol, water by 70% EtOH extract of the broccoli sprouts. Each solvent fraction was put through TLC and HPLC to separate active components. Higher antioxidant activities were observed for the butanol and ethyl acetate layers. Further evaluation of each of the 5 layers (LH1 to LH5) of the butanol fraction showed that the refined LH3 extract had a high antioxidant effect. Components with similar Rf values from TLC had the same retention times and peaks in the HPLC analysis. It was also determined that the sulforaphane content was high at the chloroform and butanol layers and the sulforaphane was responsible for, the high antioxidant activity. Thus, to use for functional materials, the butanol extract/layer of broccoli sprouts is recommended as the most effective.

• Current Photovoltaic Research
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• 제3권2호
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• pp.50-53
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• 2015

Indium (In) is widely used for transparent electrodes of photovoltaics as a form of indium tin oxide (ITO) due to its superior characteristics of environmental stability, relatively low electrical resistivity and high transparency to visible light. However, In has been worn off in proportion to growth the In related market, and it leads to raise of price. Although In is obtained from ITO target scarps, much harmful elements are used for the recycling process. To decrease of harmful elements, ITO swarf particles obtained from target scraps was characterized whether it is feasible to transparent conductive oxide (TCO). The ITO swarf was crushed with milling process, and it was mixed with new ITO nanoparticles. The mixed particles were well dispersed into ink solvent to make-up an ink, and it was well coated onto glass substrate. After heat-treatment at $400^{\circ}C$ under $N_2$ rich environments, optical transmittance at 550 nm and sheet resistance of the ITO ink coated layer was 71.6% and $524.67{\Omega}/{\square}$, respectively. Therefore, it was concluded that the ITO swarf was feasible to TCO of touch screen panel.