• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 추계학술대회 논문집 Vol.17
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• pp.89-92
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• 2004

Nowadays, the study on the ceramic components and modules that used in telecommunication system is being performed. The technology that co-fired both a ceramic material and a silver conductor is usually used to develop small telecommunication components and modules. In the study, It is that the lumped elements equivalent circuit with easy tuning control can be matched more accurate at the 50ohm than the transmission line.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제50권6호
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• pp.296-302
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• 2001

In this paper, the vector finite elements are adopted to calculate eigenvalues of RF and microwave components. Simulation results show that spurious are completely avoided because of the divergence free nature of the vector elements. This paper seeks to extend these low-order elements to higher orders to improve the accuracy of numerical solution. Investigation of numerical results for a rectangular waveguide was provided. A vector finite element program was implemented to allow propagation constants and electric field distributions to be directly computed in the rectangular and circular waveguides which are partially filled with the dielectric.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제53권5호
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• pp.273-278
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• 2004

This paper analyzed the phase noise characteristics of frequency-shifting module by figuring out the relationship between the phase noise components of 1st and 2nd local oscillator composing the frequency-shifting module and those of RF output signals shifted in frequency. Also, frequency-shifting module with the improvement of the phase noise performance was designed and implemented by means that the phase noise components of 1st local oscillator were cancelled in the output signal. Output signal has been affected by only phase noise of 2nd local oscillator, which had excellent phase noise performance than that of the 1st local oscillator.

• Journal of Ginseng Research
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• 제20권2호
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• pp.173-178
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• 1996

Aerobic cells are normally protected from the damage of free radicals by antioxidative on , zymes such as superoxide dismutase (SOD), catalase, glutathione (GSH) peroxidase, GSH S- transferase and GSH reductase which scavenge free radicals as well as nonenzymatic antioxidants such as ceruloplasmin, albumin and nonprotein-SH including GSH. The effects of each component (ginsenoside $Rb_1$, $Rb_2$, Rc, Rd, Re, $Rb_1$, Rf, $Rh_1$ and $Rh_2$) of red ginseng on the antioxidative enzyme activities were investigated in the liver in order to screen antioxidative components of red ginseng. Ginsenoside $Rb_1$ and Rc showed a tendency to increase GSH peroxidase activity, while ginsenoside Rc significantly decreased Cu,Zn-SOD activity. Especially, ginsenoside $Rh_2$ significantly increased catalase activity. These results suggest that ginsenoside $Rh_2$ is an important active component among total saponins of red ginseng.

• 생약학회지
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• 제49권3호
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• pp.270-277
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• 2018

Pyungwi-san has been used to treat the digestive system diseases, physconia, nausea, anorexia, and dyspepsia in Korea. In this study, an ultra-performance liquid chromatography-electrospray ionization-mass spectrometry (UPLC-ESI-MS/MS) method was optimized for simultaneous determination of the 14 marker components, spinosin, liquiritirn apioside, liquiritin, narirutin, 6'''-feruloylspinosin, hesperidin, liquiritigenin, glycyrrhizin, 6-gingerol, atractylenolide III, honokiol, atractylenolide II, magnolol, and atractylenolide I in Pyungwi-san extract. All analytes were separated on a Waters Acquity UPLC BEH $C_{18}$ analytical column ($2.1{\times}100mm$, $1.7{\mu}m$) with maintained at $45^{\circ}C$. The mobile phase consisted of 0.1% (v/v) aqueous formic acid and acetonitrile. The MS conditions were as follows: capillary voltage 3.3 kV, extractor voltage 3.0 V, RF lens voltage 0.3 V, source temperature $120^{\circ}C$, desolvation temperature $300^{\circ}C$, desolvation gas 600 L/h, cone gas 50 L/h and collision gas 0.14 mL/min. The coefficient of determination of 14 analytes was 0.9989-1.0000. The limits of detection and quantification values of the all analytes were 0.04-2.56 and 0.13-7.69 ng/mL, respectively. As a result of the analysis using the established LC-ESI-MS/MS method, the 5 components, spinosin, 6'''-feruloylspinosin, atractylenolide III, II, and I derived from Zizyphi Fructus and Atractylodis Rhizoma, were not detected in this extract. On the other hand, the 9 components except for the 5 components were 4.15-498.87 mg/kg in lyophilized Pyungwi-san extract. Among these components, glycyrrhizin, marker compound of Glycyrrhizae Radix et Rhizoma, was detected the most amount as a 498.87 mg/kg.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제49권12호
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• pp.654-664
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• 2000

Thin films of ZnO are deposited by using an RF magnetron sputtering with varying the substrate temperature(RT~39$0^{\circ}C$) and RF power(50~250W). Cu-doped ZnO(denoted by ZnO:Cu) films have also been prepared by co-spputtering of a ZnO target on which some Cu-chips are attached. Different substrate materials, such as Si, $SiO_{2}/Si$, sapphire, DLC/Si, and poly-diamond/Si, are employed to compare the c-axial growth features of deposited ZnO films. Texture coefficient(TC) values for the (002)-preferential growth are estimated from the XRD spectra of deposited films. Optimal ranges of RF powers and substrate temperatures for obtaining high TC values are determined. Effects of Cu-doping conditions, such as relative Cu-chip sputtering areas, $O_{2}/(Ar+O_{2})$ mixing ratios, and reactor pressures, on TC values, electrical resistivities, and relative Cu-compositions of deposited ZnO:Cu films have been systematically investigated. XPS study shows that the relative densities of metallic $Cu(Cu^{0})$ atoms and $CuO(Cu^{2+})$-phases within deposited films may play an important role of determining their electrical resistivities. It should be noted from the experimental results that highly resistive(> $10^{10}{\Omega}cm$ ZnO films with high TC values(> 80%) can be achieved by Cu-doping. SAW devices with ZnO(or Zn):Cu)/IDT/$SiO_{2}$/Si configuration are also fabricated to estimate the effective electric-mechanical coupling coefficient($k_{eff}^{2}$) and the insertion loss. It is observed that the devices using the Cu-doped ZnO films have a higher $k_{eff}^{2}$ and a lower insertion loss, compared with those using the undoped films.

• 마이크로전자및패키징학회지
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• 제14권2호
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• pp.49-57
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• 2007

본 연구에서는 Au 와 Sn을 rf-magnetron sputter를 이용하여 다층막(multilayer)과 동시증착(Co-sputter)방법으로 스퍼터링하여 기판위에 AuSn 솔더를 형성하였고, 솔더의 조성제어와 특성 분석을 통해 Sn rich AuSn 솔더의 형성 기술에 대하여 연구하였다. AuSn 솔더를 형성하기 앞서 Au와 Sn에 대하여 단일 금속 증착을 하였다. 이를 토대로 AuSn솔더를 증착하기 위한 실험 조건을 확보하였다. 증착변수로는 기판의 온도, rf 전력과 두께 비를 이용하였다. 다층막의 경우, 고온의 기판에서 솔더 합금의 표면거칠기와 조성이 보다 정확하게 제어되었다. 이에 비해 동시증착 솔더는 기판의 온도에 의한 조성의 변화가 거의 없었으나, rf전력에 의해서 조성이 보다 쉽게 제어할 수 있었다. 여기에 더해, 동시 증착 솔더 박막의 대부분은 증착동안에 금속간 화합물로 변화한 것을 알 수 있었다. 화합물의 종류는 XRD로 분석하였다. 형성된 솔더 박막을 플럭스를 이용하지 않고 리드프레임에 접합하여 접합강도를 측정하였다. 다층형의 경우 Au 10wt%의 조건에서 최대 $33(N/mm^2)$ 전단응력을 나타내었으며, 동시증착형은 Au 5wt%에서 $460(N/mm^2)$ 전단응력을 나타내었다.

• ETRI Journal
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• 제35권6호
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• pp.1156-1159
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• 2013

We investigate the characteristics of $Cu_2O$ thin films deposited through the addition of $N_2$ gas. The addition of $N_2$ gas has remarkable effects on the phase changes, resulting in improved electrical and optical properties. An intermediate phase ($6CuO{\cdot}Cu_2O$) appears at a $N_2$ flow rate of 1 sccm, and a $Cu_2O$ (200) phase is then preferentially grown at a higher feeding amount of $N_2$. The optical and electrical properties of $Cu_2O$ thin films are improved with a sufficient $N_2$ flow rate of more than 15 sccm, as confirmed through various analyses. Under this condition, a high bandgap energy of 2.58 eV and a conductivity of $1.5{\times}10^{-2}$ S/cm are obtained. These high-quality $Cu_2O$ thin films are expected to be applied to $Cu_2O$-based heterojunction solar cells and optical functional films.

• Journal of Ginseng Research
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• 제20권1호
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• pp.1-6
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• 1996

Effects of Panax ginseng on allergic reactions were studied uslng various in vivo and in vitro experimental models such as 48-hr passive cutaneous anaphylaxis, mediators-induced skin reactions, histamine release from rat peritoneal mast cells, hexosaminidase release from RBL-2H3 cells, and lipoxygenase assay . In all of anti-allergic experiments we conducted, ginseng components (50% ethanol extract or ginseng total saponin or ginsenosides) extracted from Korean red ginseng, did not show significant anti-allergic actions. In 48-hr passive cutaneous anaphylaxis and mediators-induced skin reactions, 50% ethanol extract did not suppress hypersensitivity reactions. Total saponin, 50% ethanol extract, and 8 major ginsenosides did not show inhibitory effects on lipoxygeanse activity. Ginseng total saponin did not inhibit histamine release from rat peritoneal mast cells. All of the ginseng components mentioned above were also tested on RBL-2H3 cells, but none of them inhibited hexosaminidase release from this cell line. These results suggest that Panax ginseng does not have effects on allergic reactions at the level of 50% ethanol extract or total saponin used. All of 8 major saponin components tested ($Rb_1$, $Rb_2$, Rc, Rd, Re, Rf, $Rg_1$, $Rg_2$), did not inhibit lipoxygenase activity and degranulation events.

• 한국전자파학회논문지
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• 제14권11호
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• pp.1176-1183
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• 2003

본 논문에서는 1.6 ㎓ PCS 대역 초소형 전압제어발진기를 LTCC 기술을 이용하여 구현하였다. 상용부품들을 사용하여 VCO 회로를 설계하고, LTCC 기판 내부에 실장될 인덕터, 캐패시터들을 시뮬레이션을 통하여 최적으로 설계하였다. 설계된 수동소자들은 시뮬레이션을 위하여 등가회로로 모델링한 후 회로 파라메타를 추출하였다. 모델링된 내장형 부품과 21층 구조의 LTCC 기 판을 이용하여 전압제어 발진기를 설계하였으며, 4.0${\times}$4.0${\times}$1.6 ㎣ 크기의 VCO를 제작하였다. 제작된 전압제어 발진기의 동작전압은 2.7 V, 소모전류는 최대 8.5 ㎃ 이하이었으며, 동작주파수는 1,620∼l,650 MHz이다. 또한 동작주파수 내에서의 위상잡음특성은 100 KHz offset에서 -ll2.67 ㏈c/Hz의 우수한 특성을 지녔으며, -30 ㏈ 이상의 고조파억압특성을 보였다.