• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.13 no.12
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• pp.1051-1057
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• 2000

A traveling-wave CPW(coplanar waveguide) electrode with abruptly broken input/output-taper for LiNbO$_3$optical modulator was designed and fabricated. The electrical characteristics of traveling-wave electrode on z-cut LiNbO$_3$crystal with SiO$_2$buffer layers were measured by network analyzer. To confirm the possibility of the electro-optic modulator electrode, detailed calculations of the impedance, microwave effective index and attenuation constants are presented as a function of the microwave electrode thickness, but the buffer layer thickness is fixed as 1${\mu}{\textrm}{m}$. These characteristics are discussed from the viewpoint of the device optimization and are expected to be design guides for the LiNbO$_3$modulator’s electrodes.

• Bulletin of the Korean Chemical Society
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• v.27 no.5
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• pp.718-724
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• 2006

The heterogeneous association behaviour of various concentration binary mixtures of mono alkyl ethers of ethylene glycol with ethyl alcohol were investigated by dielectric measurement in benzene solutions over the entire concentration range at 25 ${^{\circ}C}$. The values of static dielectric constant $\epsilon_0$ of the mixtures were measured at 1 MHz using a four terminal dielectric liquid test fixture and precision LCR meter. The high frequency limiting dielectric constant $\epsilon_\infty$ values were determined by measurement of refractive index $n_D$ ($\epsilon_\infty\;=\;n_D\;^2$). The measured values of $\epsilon_0$ and $\epsilon_\infty$ were used to evaluate the values of excess dielectric constant $\epsilon^E$, effective Kirkwood correlation factor $g^{eff}$ and corrective correlation factor $g_f$ of the binary polar mixtures to obtain qualitative and quantitative information about the H-bond complex formation. The non-linear behaviour of the observed $\epsilon_0$ values of the polar molecules and their mixtures in benzene solvent confirms the variation in the associated structures with change in polar mixture constituents concentration and also by dilution in non-polar solvents. Appearance of the maximum in $\epsilon^E$ values at different concentration of the polar mixtures suggest the formation of stable adduct complex, which depends on the molecular size of the mono alkyl ethers of ethylene glycol. Further, the observed $\epsilon^E$ < 0 also confirms the heterogeneous H-bond complex formation reduces the effective number of dipoles in these polar binary mixtures. In benzene solutions these polar molecules shows the maximum reduce in effective number of dipoles at 50 percent dilutions. But ethyl alcohol rich binary polar mixtures in benzene solvent show the maximum reduce in effective number of dipoles in benzene rich solutions.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.41 no.3
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• pp.45-54
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• 2004

Microwave characteristics of ridge type CPW traveling-wave(TW) electroabsorption modulator and photodetector are affected by the thickness of intrinsic layer, width of guiding layer, and the separation of signal and ground electrodes. These factors are determined effective index of microwave and characteristic impedance due to changing of capacitance(C) and inductance(L) of device. However, conventional equivalent circuit of TW-structure is approximated to microstrip and CPW transmission line by distribution of electric and magnetic fields, respectively. In this paper, we analyzed microwave characteristics of TW-structure and found more accurate value of C and L by using finite difference time domain (FDTD) method. These values are adopted circuit element of equivalent circuit. Microwave characteristics obtained by the FDTD and equivalent circuit model show good agreement.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.11
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• pp.4545-4548
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• 2014

Objective: To investigate the changes of serum vascular endothelial growth factor (VEGF), soluble interleukin-2 receptor (SIL-2R) and hepatocyte growth factor (HGF) contents in patients with primary hepatocellular carcinoma (HCC) before and after percutaneous microwave coagulation therapy (PMCT) and determine their clinical significance. Materials and Methods: Fasting venous blood (3 mL) from 81 patients with primary HCC diagnosed by pathology was collected in the mornings 1 day before PMCT, and 1 day, 7 days and 1 month after PMCT, and then the serum was separated and stored in $-70^{\circ}C$. The contents of VEGF, SIL-2R and HGF were detected by enzyme linked immunosorbent assay (ELISA). Results: The serum VEGF, SIL-2R and HGF contents in 81 patients with primary HCC had obviously dynamic changes before and after PMCT. By comparison to 1 day after PMCT with pre-operation, there was no statistical significance regarding VEGF and SIL-2R contents (P>0.05), but HGF content showed significant difference (P<0.01). Compared with pre-operation, VEGF, SIL-2R and HGF contents 7 days and 1 month after PMCT all manifested significant differences (P<0.01). By comparison to 7 days with 1 month after PMCT, there was no statistical significance regarding the VEGF content (P>0.05), whereas SIL-2R and HGF contents showed significant change (P<0.01). Conclusions: The contents of serum VEGF, SIL-2R and HGF have obviously dynamic changes in primary HCC before and after PMCT, and their joint detection is expected to be an effective hematologic evaluation index of PMCT for primary HCC.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.29A no.8
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• pp.41-48
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• 1992

The characteristics of traveling-wave electrodes for high-frequency electroptic integrated devices are described from the view point of improvement of phase-matching based on the conformal mapping method. Specific calculations of the characteristic impedance, effective microwave index, and eletrode loss for asymmetric coplanar strip(ACPS) and coplanar waveguide(CPW) electrode structures are presented as a function of the geometric electrode parameters including the electrode thickness and buffer layer thickness. 5-10(x10S0-6Tm) thick Au-ACPS electrodes were successfully fabricated by electroplating and ECR etcher. The improvement of modulation bandwidth can be theoretically observed from the combination of electrode and buffer layer thickness.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.05a
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• pp.282-285
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• 1999

Fabrication and pakaging method for low delve voltage and 10Gbps Ti diffused waveguide LiNbO$_3$ optical intensity modulator are described. Optical waveguides were prepared by conventionaly electron-beam evaporation and Ti-indiffusion into Z-cut plate LiNbO$_3$. Traveling-wave electrodes were used for obtaining the wideband frequency response and impedance matching. Microwave effective index and characteristic impedance measured by time domain reflectometry and compared with the calculated value by conformal mapping. The characteristics of 10Gbps modulator at the 1550nm wavelength are as follows : perfect modulation voltage Is about 5V, optical insertion loss Is about 5dB, 3-dB bandwidth is 10GHz, and characteristic impedance is about 50$\Omega$.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.1
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• pp.89-95
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• 1997

X-cut y-propagation $LiNbO_{3}$ optical modulator is analyzed by finite element calculation. the purpose of this trial is the design of wide-bandwidth x-cut $LiNbO_{3}$ optical modulator with ridge wave guide, which was only applied to z-cut $LiNbO_{3}$ optical modulator. the simulation tool is examined by the comparison between our results and Becker's. And we consider the optimum position of optical waveguide to electrodes for decreasing the driving voltage. The calculated driving-voltage, characteristic impedance and microwave effective index at $1.3{\mu}{\textrm{m}}$ optical wavelength are 18 V.cm, $48.13{\Omega}$ and 2.168, respectively.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.11 no.7
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• pp.1211-1217
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• 2000

The three-dimensional finite-difference time-domain (FDTD) method and the two-dimensional quasi-static formulation have been used to calculate the characteristic impedance and the microwave effective index of coplanar waveguide structures on Lithium Niobate ($LiNBO_3$) single crystal substrates with a yttria-stabilized zirconia (YSZ) or $SiO_2$ buffer layer. The results shown can be a good source to predict the modulator characteristics. The effects of the thin buffer layer and anisotropy of the $LiNBO_3$ crystal (x-cut and z-cut) are discussed. The comparison between the FDTD and quasi-static results shows good agreement. In this paper, the efficient modeling technique of the FDTD method for the coplanar waveguide (CPW) structures based on an anisotropic substrate with a thin buffer layer is developed.

• Nutrition Research and Practice
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• v.7 no.5
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• pp.359-365
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• 2013

Anthocyanin from purple sweet potato (PSP) extracted by microwave baking (MB) and acidified electrolyzed water (AEW) exhibited antioxidant activity. After further purification by macroporous AB-8 resin, the color value of PSP anthocyanin (PSPA) reached 30.15 with a total flavonoid concentration of 932.5 mg/g. The purified extracts had more potent antioxidant activities than the crude extracts. After continuously administering the PSP extracts to 12-mo-old mice for 1 mo, the anti-aging index of the experimental group was not significantly different from that of 5-mo-old mice. To a certain degree, PSPA was also effective for controlling plasma glucose levels in male Streptozocin (STZ)-treated diabetic mice. In addition, the extracts inhibited Sarcoma S180 cell growth in ICR mice. Mice consuming the PSP extracts formed significantly fewer and smaller sarcomas than mice consuming the control diets. The highest inhibition rate was 69.03%. These results suggest that anthocyanin extracts from PSP not only exert strong antioxidant effects in vitro, but also had anti-aging, anti-hyperglycemic, and anti-tumor activities.

• Proceedings of the KSRS Conference
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• 2007.10a
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• pp.278-281
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• 2007

The purpose of this study is to develop snow and sea ice detection algorithm in Communication, Ocean and Meteorological Satellite (COMS) meteorological data processing system. Since COMS has only five channels, it is not affordable to use microwave or shortwave infrared data which are effective and generally used for snow detection. In order to estimate snow and sea ice coverage, combinations between available channel data(mostly visible and 3.7 ${\mu}m$) are applied to the algorithm based on threshold method. As a result, the COMS snow and sea ice detection algorithm shows reliable performance compared to MODIS products with channel limitation. Specifically, there is partial underestimation over the complicated vegetation area and overestimation over the area of high level clouds such as cirrus. Some corrections are performed by using water vapor and infrared channels to remove cloud contamination and by applying NDVI to detect more snow pixels for the underestimated area.