• 한국마이크로전자및패키징학회:학술대회논문집
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• 한국마이크로전자및패키징학회 2000년도 추계 기술심포지움 논문집
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• pp.89-92
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• 2000

테입 캐스터를 이용하여 바인더/가소제, 글말함량 비율이 다른 LTCC 테입을 제작한 후 특성평가를 하고자 하였다. 슬러리 조성은 서로 다른 바인더/가소제 그리고 분말함량에 따라 각각 4개 조성으로 구성하였다. 모든 슬러리에서 발포나 핀홀이 없는 미려한 표면을 갖는 테입을 얻을 수 있었다. 가장 우수한 기계적 특성 특성은 B/P=3.0, 분말함량 70vo1%인 두께 52 $\mu\textrm{m}$인 테입에서 인장강도 4.6MPa, 신을 29.5%의 특성을 얻을 수 있었다.

• E2M - 전기 전자와 첨단 소재
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• 제10권5호
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• pp.492-499
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• 1997

• 대한전자공학회논문지
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• 제27권9호
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• pp.1344-1350
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• 1990

A design method of ultra-broadband microwave amplifier is presented. A lossy network is represented as the combination of a serial impedance component and a parallel admittance component, and the realizable ranges of the gain and the reflection coefficients are derived with the components connected to the input, output or interstage network. The matching network has been designed by using the serial and parallel immittance loci which have the constant gain or reflection coefficients within the realizable ranges. Using the proposed method, deisgn examples of ultra-broadband amplifiers operating from dc to 12GHz frequency range are presented.

• 한국세라믹학회지
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• 제40권4호
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• pp.346-349
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• 2003

Microwave dielectric characteristics and physical properties of the new Zr$_{1-x}$ (Bn$_{1}$3/Nb$_{2/3}$)xTi $O_4$ (0.2$\leq$x$\geq$ 1.0) system have been investigated as a function of the amount of Bn$_{1}$3/Nb$_{2/3}$ $O_2$substitution. With increasing Bn$_{1}$3/Nb$_{2/3}$ $O_2$ content (x), two phase regions were observed: $\alpha$-Pb $O_2$ solid solution (x<0.4), mixture of the rutile type Zn$_{1}$3/Nb$_{2/3}$Ti $O_4$ and the $\alpha$-Pb $O_2$ solid solution (x$\geq$0.4). In the$\alpha$-Pb $O_2$solid solution region below x<0.4, the Q.f$_{0}$ value sharply increased and the Temperature Coefficient of the Resonant Frequency(TCF) decreased with increasing Bn$_{1}$3/Nb$_{2/3}$ $O_2$ contents while dielectric constant (K) showed nearly same value. In the mixture region above x$\geq$4, the dielectric constant and TCF increased with increasing Bn$_{1}$3/Nb$_{2/3}$ $O_2$ content. Zr$_{1-x}$ (Zn$_{1}$3/Nb$_{2/3}$)xTi $O_4$ materials have excellent microwave dielectric properties with K=44.0, Q.f$_{0}$ : 41000 GHz and TCF =-3.0 ppm/$^{\circ}C$ at x=0.35.=0.35. x=0.35.=0.35.

• 한국식품영양과학회지
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• 제27권1호
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• pp.121-125
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• 1998

The effects of various cooking methods (blanching, microwave heating, and deep-fat frying) on biologically active components of Angelica keiskei were determined by HPLC. Cynharoside, the biologically active component of Angelica keiskei leaves was 4.82%, which was rapidly decreased by blanching, showing 3.79%, 2.59% and 1.74% at 1 min, 2min and 3min, respectively. Microwave heating also decreased the cynaroside contents slowly by 2 min and rapidly by 3min, respectively. Microwave heating also decreased the cynaroside contents slowly by 2min and rapidly by 3 min, showing 4.25% at 1 min, 3.38% at 2 min, and 1.49% at 3 min. Among the cooking methods tested, deep-fat frying was shown to preserve the cynaroside most. Only 3.90% of cynaroside was lost by 5 min frying. The decrease in cynaroside in each cooking method was supposed to be due to the conversion of cynarside, a glycoside of flavonoid, into luteolin through lysis of glucose at C-7 position on cynaroside.

• Journal of Multimedia Information System
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• 제6권3호
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• pp.155-164
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• 2019

We intended to confirm that microwave attenuation by tree leaves is strongly linked to water content in leaves. We sampled natural broadleaves, including Japanese cinnamon, and investigated their effects on the microwave (3 to 20 GHz) frequency characteristics using a network analyzer. Experiments determined that microwave attenuation by foliage increases as a linear function of frequency per unit weight (gram). As the frequency increases, the spatial resolution increases, but the phase difference (imaginary component) increases. So we solved the dispersion of phase difference by sweeping the frequency and taking the intermediate value. Based on these experimental results, we developed a microwave scanner on 10Ghz to describe foliage moisture as a image and to enable assessments of leaf condition. Photosynthesis is the process whereby plants synthesize oxygen and sugars from carbon dioxide and water, thereby converting light energy into chemical energy. Since water is a major parameter of photosynthesis, the quantity of water accumulated inside a leaf reflects leaf health. The equipment described here and related microwave technologies will help assess the capacity of leaves to absorb atmospheric carbon dioxide.

• 한국식품과학회지
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• 제35권2호
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• pp.222-228
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• 2003

팽이버섯 추출물의 수율 및 전자공여작용, 총폴리페놀함량, tyrosinase 저해작용, 갈색도, 아질산염 소거작용에 대하여 반응표면분석에 의해 추출조건을 최적화 하였다. 팽이버섯 추출물의 수율변화는 에탄올 농도에 가장 큰 영향을 받았으며, 갈변도는 microwave power 보다는 에탄올 농도에 크게 영향을 받는 것으로 나타났으며, 아질산염 소거작용의 경우 에탄올 농도가 증가할수록, microwave power가 감소할수록 증가하는 경향을 나타내었다. 전자공여작용의 경우 에탄올 농도가 증가할수록 증가폭이 컸고, microwave가 증가할수록 조금씩 증가하는 경향을 보였다. 총 폴리페놀 함량의 경우 에탄올 농도가 증가할수록, microwave power가 클수록 추출물의 생리활성이 우수한 것으로 나타나 에탄올 농도가 추출시 중요한 공정인자임을 확인 할 수 있었다. 한편, tyrosinase 저해 작용의 경우 에탄올 농도보다는 microwave power에 영향을 받았는데 power가 작을수록 그 값은 크게 측정되었다. 따라서 팽이버섯의 최적 추출조건 범위는 microwave power $47.21{\sim}76.05$ watt, ethanol 농도 $10.25{\sim}43.56%$, 추출시간 5.72분으로 예측되었다.

• Korean Chemical Engineering Research
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• 제56권5호
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• pp.773-778
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• 2018

In-situ transesterification of microalgae lipids using microwave irradiation has potential to simplify and accelerate biodiesel production, as it minimizes production cost and reaction time by direct transesterification of microalgae into biodiesel with microwave as a heating source. This study was conducted to research the effect of microwave irradiation with in-situ transesterification of microalgae under base catalyst condition. The process variables (reaction time, solvent ratio, microwave power) were studied using 2% of catalyst concentration. The maximum yield of FAME was obtained at about 32.18% at the reaction time of 30 min with biomass-methanol ratio 1:12 (w/v) and microwave power of 450 W. The GC MS analysis obtained that the main component of FAME from microalgal oils (or lipids) was palmitic acid, stearic acid and oleic acid. The results show that microwaves can be used as a heating source to synthesize biodiesel from microalgae in terms of major components resulting.

• 한국세라믹학회지
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• 제29권3호
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• pp.177-182
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• 1992

The effect of heat-treatment temperature on the microwave absorbing properties was investigated in Ni0.8Zn0.2Fe2O4 specimens. The composite specimens were prepared by modling and curing the mixture of prereacted ferrite powder and silicone rubber. The measurement of complex permeability and permittivity was made by the reflection/transmission method. The most sensitive material constants with heat-treatment temperature is the imaginary (loss) component of permeability. The higher the heat-treatment temperature, the greater the magnetic loss. The composite specimens with high magnetic loss exhibited superior microwave absorbing properties. The quantitative estimation of microwave absorbing properties were made by plotting the observed material constants on the calculated solution map of impedance-matching.

• 대한화학회지
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• 제55권6호
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• pp.936-939
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• 2011

Thiamine hydrochloride (VB1) has been used as an acid catalyst in organic synthesis. One pot three component Biginelli condensation of dimedone, urea/thiourea and substituted aromatic aldehydes catalyzed by 10 mol % of thiamine hydrochloride (VB1) in solvent free condition under microwave irradiation in good to excellent yields has been investigated. Utilization of microwave irradiation, simple reaction conditions, short reaction time, ease of product isolation, and purification makes this manipulation very interesting from an economic and environmental perspective.