• Current Optics and Photonics
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• v.7 no.2
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• pp.127-135
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• 2023

Radially polarized beams with the ability to generate a sub-wavelength sized spot in a longitudinal field provides significant applications in microscopic imaging, optical tweezers, lithography and so on. However, this excellent property can also be achieved based on conventional circularly polarized beams. Here, we demonstrate its ability to create a strong longitudinal field by comparing the tight focusing characteristics of fractional-order vortex modulated radial polarized and left-handed circular polarized Bessel-Gauss beams. Additionally, the possibility of generating arbitrary fractional-order vortex modulated Bessel-Gauss beams with a strong longitudinal field is demonstrated. A special modulation method of left-handed circularly polarized Bessel-Gauss beams modulated by a fractional-order vortex is adopted creatively and a series of regulation laws are obtained. Specifically, the fractional-order phase modulation parameter n can accurately control the number of optical lobes. The ratio of the pupil radius to the incident beam waist β₁ can control the radius of the optical lobes. The first-order Bessel function amplitude modulation parameter β₂ can control the number of layers of optical lobes. This work not only adds a new modulation method for optical micromanipulation and optical communication, but also enriches the research on fractional vortex beams which has very important academic significance.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.5 s.347
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• pp.162-168
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• 2006

Understanding of propagation characteristics is very important for the wireless communication system design and wireless communication service construction. In this paper, propagation characteristics is measured and analyzed at 2.45Ghz frequency band under curved subway tunnel environment. We constituted channel measurement system with sliding correlation and five different kind of antennas. The purpose of five different type of antennas is to compare propagation characteristics according to beam shape of antennas. The path loss under tunnel environment is average $4.38^{\sim}14.41dB$ lower than free space and circular polarization antenna marked smallest path loss. Also, path loss is smallest when the receiver antenna located outside of tunnel in th curved section. 90% of delay components of all antennas measured within 20ns and directional antenna has more wide coherence bandwidth than omni-directional antenna. According to measured result, when we consider path loss and delay characteristics, circular polarization antenna is most suitable under tunnel environment.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.38 no.8
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• pp.1-12
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• 2001

The adaptive learning circuit is designed on the basis of modeling of MFSFET (Metal-Ferroelectric-Semiconductor FET) and the numerical results are analyzed. The output frequency of the adaptive learning circuit is inversely proportional to the source-drain resistance of MFSFET and the capacitance of the circuit. The saturated drain current with input pulse number is analogous to the ferroelectric polarization reversal. It indicates that the ferroelectric polarization plays an important role in the drain current control of MFSFET. The output frequency modulation of the adaptive learning circuit is investigated by analyzing the source-drain resistance of MFSFET as functions of input pulse numbers in the adaptive learning circuit and the dimensionality factor of the ferroelectric thin film. From the results, the frequency modulation characteristic of the adaptive learning circuit are confirmed. In other words, adaptive learning characteristics which means a gradual frequency change of output pulse with the progress of input pulse are confirmed. Consequently it is shown that our circuit can be used effectively in the neuron synapses of nueral networks.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.50 no.5
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• pp.361-367
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• 2005

Single nucleotide polymorphisms (SNPs) are valuable DNA markers due to their abundance and potential for use in automated high-throughput genotyping. Numerous SNP genotyping assays have been developed. In this report, one of effective and high throughput SNP genotyping assays, which was named the template-directed dye-terminator incorporation with fluorescence polarization detection (FP-TDI) was described. Although the most of this assay succeed, the objective of this work was to deter­mine the reasons for the failures, find ways to improve the assay and reduce the running cost. Ninety $F_2$-derived soybean, Glycine max (L.) Merr., RILs from a cross between 'Pureunkong' and 'Jinpumkong 2' were genotyped at four SNPs. FP measurement was done on $Victot^3$ microplate reader (perkinelmer Inc., Boston, MA, USA). Increasing the number of thermal cycles in the single-base extension step increased the separation of the FP values between the products corresponding to different genotypes. But in some assays, excess of heterozygous genotypes was observed with increase of PCR cycles. We discovered that the excess heterozygous was due to misincorporation of one of the dye­terminators during the primer extension reaction. After pyrophosphatase incubation and thermal cycle control, misincoporation can be effectively prevented. Using long amplicons instead of short amplicons for SNP genotyping and decreasing the amount of dye terminator and Acyclopol Taq polymerase to 1/2 or 1/3 decreased the cost of the assay. With these minor adjustments, the FP-TDI assay can be used more accurately and cost-effectively.

• Journal of Physiology & Pathology in Korean Medicine
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• v.18 no.2
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• pp.580-585
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• 2004

BJYGC is often clinically used as a treatment of allergic rhinitis. This study was aimed to find out the effect BJYGC would have on the helper T cell, and how it can promote the subsets of helper T cells to regain their balance that they lost due to immunological diseases. Splenocytes were prepared from BALB/c mice was cultured without stimulation in the presence of BJYGC for 48 hr. The viability of CD4 T cells from Balb/c mouse were measured at various concentrations of BJYGC using the MTS assay. It was somewhat increased up to concentration of 400 ㎍/ml, but did not show any significant difference. Proliferation was measured using the MTS assay, CD4 Th cells were stimulated with anti-CD3/28 in the presence of BJYGC for 48 hr. As evidence for rapid T cell activation, CD25 expression by flow cytometry was evaluated at 10, 50, 100 and 200 ㎍/㎖ of BJYGC. Th cell differentiation experiments were performed to examine whether BJYGC can affect the Th polarization process. CD4 T cells were activated in culture under neutral, Th1-polarized or Th2-polarized conditions in the presence of BJYGC at 10, 100 and 200 ㎍/㎖. Cytokine production was measured by ELISA. This experiment proved that BJYGC could inhibit the secretion of both IL-4 and IFN-γ in neutral condition and polarized condition, too. Considering that BJYGC shows an excellent effect on treating allergies, the author can conclude that its pharmacological action may be associated with decreased IL-4 and, it may also regulate IFN-γ depending the host's need. Also, it was discovered that Th1 cell was pathologic in chronic inflammatory tissue specific diseases, such as insulin dependent diabetes mellitus, multiple sclerosis, RA, and uveitis. We are counting on the BJYGC to be able to control the tendency of Th1 cell predominancy in an immune reaction.

• Journal of the Microelectronics and Packaging Society
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• v.17 no.3
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• pp.71-77
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• 2010

Mg alloys have been used in automobile industry, aerospace, mobile phone and computer parts owing to low density. However, they have a restricted application because of low mechanical and poor corrosion properties. Thus, improved surface treatments are required to produce protective films. Environmental friendly Plasma Electrolytic Oxidation(PEO) was used to produce protective films on magnesium alloys. PEO process is combined electrochemical oxidation with plasma treatment in the aqueous solution. In this study, the effects of applied voltage and applied current on the surface morphologies were investigated. Also, the effects of Direct Current(DC) and Pulse Current(PC) were compared. PC and constant current control gave the dense coating on the Mg alloy. The potentiodynamic polarization tests were carried out for the analysis of corrosion properties of specimens. The surface hardness was 5 times higher than that of untreated AZ91D.

• Journal of the Korean Ceramic Society
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• v.42 no.11 s.282
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• pp.749-752
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• 2005

When an electric field higher than a characteristic coercive field is applied to a ferroelectric such as $LiNbO_3$, the orientation of the spontaneous polarization is reversed, which causes the reversal of the sign of odd-rank tensor properties such as electro-optic and nonlinear optic coefficients. A fabrication process of insulator and periodic external field assisted poling of a z-cut $LiNbO_3$ have been optimized for a periodic $180^{\circ}$ phase inversion along z-axis. The poling jig and the poling control system, fully controlled by a computer, for high quality and reproducible PPLN fabrication have been devised. Periodically polarization reversed PPLN was adjusted based on the fabricated thickness of insulator. The poling structure of PPLN was observed under a microscope after etching PPLN samples by an etching solution ($HF:HNO_3$ = 1 : 2) for about 15 min.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.13 no.4
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• pp.300-305
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• 2000

We have investigated the dielectric and electrical characteristics of palmitic acid(PA) stearic acid(SA) and arachidic acid(AA) Langmuir-Blodgett(LB) films because these fatty acid systems have a same hydrophilic group and a different hydrophobic one(methylene group or alkyl chain length). The fatty acid systems were used as LB films and the status of the deposited films was confirmed by evaluating the transfer ratio the UV absorption and the capacitance. The dielectric characteristics such as the frequency-capacitance characteristics and the dielectric dispersion and absorption characteristics of PA SA and AA through-plane were measured. The relative dielectric constants of PA, SA and AA LB films were about 3.0~4.6, 2.7~3.0 and 2.4~3.0 respectively. That is the relative dielectric constants were decreased in proportion to the chain length of methylene group. Also the dielectric dispersion and absorption of each fatty acid LB films have arisen from spontaneous polarization of dipole polarization in the range of 10$^4$~10$^{5}$ ［Hz］. The conductivity of PA, SA and AA LB films obtained from I-V characteristics were about 9$\times$10$^{-14}$ , 3$\times$10$^{-14}$ and 5$\times$10$^{-15}$ ［S/cm］. respectively. These results have shown the insulating materials and could control the conductivity y changing the length of methylene group. Also we have confirmed that the barrier height of fatty acid systems were almost the same ones obtained from dielectric characteristics.

• Journal of The Korean Society of Agricultural Engineers
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• v.55 no.6
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• pp.19-30
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• 2013

This study is to evaluate the use of dual-polarization radar data for storm runoff modeling in Namgang dam (2,293 $km^2$) watershed using KIMSTORM (Grid-based KIneMatic wave STOrm Runoff Model). The Bisl dual-polarization radar data for 3 typhoons (Khanun, Bolaven, Sanba) and 1 heavy rain event in 2012 were obtained from Han River Flood Control Office. Even the radar data were overall less than the ground data in areal average, the spatio-temporal pattern between the two data was good showing the coefficient of determination ($R^2$) and bias with 0.97 and 0.84 respectively. For the case of heavy rain, the radar data caught the rain passing through the ground stations. The KIMSTORM was set to $500{\times}500$ m resolution and a total of 21,372 cells (156 rows${\times}$137 columns) for the watershed. Using 28 ground rainfall data, the model was calibrated using discharge data at 5 stations with $R^2$, Nash and Sutcliffe Model Efficiency (ME) and Volume Conservation Index (VCI) with 0.85, 0.78 and 1.09 respectively. The calibration results by radar rainfall showed $R^2$, ME and VCI were 0.85, 0.79, and 1.04 respectively. The VCI by radar data was enhanced by 5 %.

• Korean Journal of Materials Research
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• v.11 no.3
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• pp.207-214
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• 2001

Silica glass is a core material for optical fiber in optical telecommunications, but its centrosymmetry eliminates the second order nonlinearity. But it is experimentally well known that the space charge polarization induces the Second Harmonic Generation (SHG) when a strong DC voltage is applied to silica glass for a long period of time with metal blocking electrodes. In this report, the results of a theoretical calculation of the nonlinear optical property caused by the space charge polarization, and a model of a numerical analysis to predict the small chance in nonlinear optical property as functions of time and space are provided. Assuming that amorphous silica is a solid state electrolyte and sodium ion is the only mobile charge carrier, 'Finite Difference Method' was employed for modeling of numerical analysis. The distributions of the concentration of sodium ion and electric field as functions of a normalized length of the specimen and a normalized applied voltage were simulated.