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Electromagnetic radiation from a circular cavity with multiple circular apertures in a conducting plane is investigated. An electromagnetic boundary-value problem of the circular cavity with circular apertures is solved based on the Green's function, integral transform, superposition, and mode matching method. The radiated fields from the circular cavity are calculated in terms of the aperture geometry to understand the radiation behaviors and measured to check the validity of our theoretical formulations. [ABSTRACT FROM PUBLISHER]

This letter examines the capacitance of coplanar waveguides (CPWs) in multilayer dielectric substrates.An electrostatic boundary-value problem of CPWs in multilayer dielectric substrates is solved based on the Fourier transform, mode matching technique, and superposition considering the conductor thickness. A series representation for the capacitance is presented. The capacitance is calculated in terms of the CPW geometry to illustrate its behaviors. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:1886-1889, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26938 [ABSTRACT FROM AUTHOR]

In this letter, the capacitance of a conductor-backed coplanar waveguide (CPW) with an upper shielding is investigated.An electrostatic boundary-value problem of the conductor-backed CPW with an upper shielding is solved using the Fourier transform, mode matching technique, and superposition. The capacitance of the conductor-backed CPW is represented in a series and calculated in terms of the CPW geometry. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:1364-1368, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26007 [ABSTRACT FROM AUTHOR]

We investigated magnetostatic field penetration into multiple annular apertures in a thick conducting plane. We rigorously solved a magnetostatic boundary-value problem of multiple annular apertures using the Hankel transform, eigenfunction expansion, and superposition. We represented magnetic polarizability in a rapidly convergent series and computed it in terms of aperture geometry and incident angles to understand the magnetostatic field penetration. [ABSTRACT FROM PUBLISHER]

Abstract: Electrostatic potential penetration into a circular enclosure with circular apertures is investigated. An electrostatic boundary-value problem of the circular enclosure with circular apertures is solved based on the Hankel transform, mode matching technique, and superposition. The polarizability of the circular apertures is represented in a series and calculated in terms of the aperture geometry to understand the behaviors of potential penetration. [Copyright &y& Elsevier]

Abstract: Ninety two samples of child-consumed candies and candy packages were analyzed for seven heavy metals. Lead (Pb) was detected at concentrations of 110.3–6394.1mgkg−1 in ten of 92 candy packages. The directive factor of Pb contamination had originated in the lead-based ink of the outer cover. Particularly, Pb was detected at high concentrations in case of green- or yellow-colored packages. Chromium (Cr) was detected at high concentrations in cases where Pb was also detected at high concentrations, and the Cr levels ranged from 136.9mgkg−1 to 1429.3mgkg−1 in seven of the 92 candy packages. Hexavalent chromium [Cr(VI)] was detected at 87–105.0% of the total Cr in polypropylene-coated wrappers with printed outer covers. The migration of Cr(VI) increased with elution time up to 0.20μg (cm2)−1 for 30 days in basic (pH 10.0) solution; however, there were no migrations in acidic (pH 4.0) and neutral (pH 7.0) solutions. The migration of Pb increased with elution time up to 0.65μg (cm2)−1 and 0.28μg (cm2)−1 in basic (pH 10.0) and acidic (pH 4.0) solutions, respectively. However, any migration was hardly observed in neutral (pH 7.0) solution. [Copyright &y& Elsevier]

Abstract: Capacitance of a coaxial line terminated by a gap is investigated. An electrostatic boundary-value problem of the coaxial line terminated by a gap is rigorously solved based on the Fourier sine transform, mode matching technique, and superposition. The capacitance of the coaxial line is represented in a fast-convergent series and computed in terms of the gap geometry and the gap permittivity. [Copyright &y& Elsevier]

This paper investigates a low-Earth orbit (LEO) satellite downlink for high-speed data communication in interference situations. A choke ring horn type antenna is used as the data transmitting antenna with an isoflux pattern in the LEO satellite, which has a beam coverage of ±51.6° and a bore-sight gain of 4.4 dBi at 8 GHz. The receiving antenna on the ground station is a parabolic type antenna with a diameter of 11.3 m, and it has a half-power beam width (HPBW) of 0.2° with a maximum gain of 59 dBi at 8 GHz. The jamming-to-signal ratio (J/S) is calculated assuming that the LEO satellite transmits signals to the ground station, and an elevation angle of the interference source varies from 0° to 90° at an altitude of 10 km. Applying antenna characteristics, such as HPBWs and side lobes, to the calculated space wave path loss makes it possible to predict the J/S results according to the location of the interference source and the satellite. The results show that it is necessary to consider the space environment to accurately analyze the LEO satellite downlink, especially at the low elevation angle of the satellite. [ABSTRACT FROM AUTHOR]

It is important to determine the position of the receiver (Rx) coils in wireless power transfer (WPT) system, and to control the power transmitted to the Rx coil based on this result. In particular, in a situation where there is no feedback between the primary side and the secondary side, it is difficult to control the received power because the information is limited. In this paper, a method for determining the position of the Rx coils and controlling the received power using limited parameters in a feedback-free WPT system is proposed. The proposed method is verified by constructing a 4 × 2 WPT system, and it is validated that the simulation result and the experimental result are consistent well. Furthermore, arbitrary power can be transmitted to the Rx coil based on the result of the position of the Rx coil. The experiment is conducted by transmitting about 1 W to Rx 1 and Rx 2, and the efficiency for Rx 1 is about 32.93 % , Rx 2 is 25.03 % , and the overall efficiency is confirmed to be 57.96 % . [ABSTRACT FROM AUTHOR]

Recently, based on a quadratic complex rational function, a simple and accurate finite-difference time-domain algorithm was introduced for the study of electromagnetic wave propagation in dispersive media. It is of great necessity to investigate the numerical stability of the quadratic complex rational function–finite-difference time-domain to fully utilize this finite-difference time-domain algorithm. In this work, using the von Neumann method with the Routh–Hurwitz criterion, the numerical stability conditions of the quadratic complex rational function–finite-difference time-domain are investigated. It is shown that the numerical stability conditions of the quadratic complex rational function–finite-difference time-domain are not same as those of the conventional finite-difference time-domain schemes. [ABSTRACT FROM AUTHOR]

Electromagnetic transmission through a slit surrounded by rectangular grooves in a conducting plane is investigated. An electromagnetic boundary-value problem associated with a slit surrounded by rectangular grooves in a conducting plane is rigorously solved based on the Fourier transform, eigenfunction expansion and mode matching method. The transmission coefficient through the slit is represented in a series. Computation is performed to illustrate the effect of the groove geometry on the transmission behaviours. [ABSTRACT FROM AUTHOR]

HPLC method for quantitative determination of four preservatives and nine UV filters worldwide authorized in commercial suncare product was developed and validated, and then 101 samples of commercial suncare products were analyzed for the UV filters and preservatives using the proposed method. The mobile phase was acetonitrile-water containing 0.5% acetic acid using a gradient elution at a flow rate of 0.9 mL/min and UV measurements were carried out at 320 nm for UV filters and 254 nm for preservatives. The correlation coefficients of each calibration curves were mostly higher than 0.999. The percent relative standard deviations (%RSD) ranged from 0.97% to 6.1% for five sample aliquots. The recoveries from the spiked solutions were 98–102%. 2-ethylhexyl-p-methoxycinnamate (EHMC) was detected in 96 of 101 commercial suncare products and the concentration was in the range of 3.08–8.16% and 18 samples were found to exceed the 7.5% which has been defined as the maximum allowed concentration in Korea. Methyl paraben was detected in 81 of 101 samples and the next-most often detected preservatives were propyl paraben (25), ethyl paraben (18), and butyl paraben (4). Three samples of 101 suncare products exceeded the maximum allowed concentration (i.e., 0.58–0.79%). The proposed HPLC method allows efficient and simultaneous analysis of preservatives and UV filters suitable for quality control assays of commercial suncare products. [ABSTRACT FROM AUTHOR]

This article analyzes the number of duct occurrences in the Korean coastal area by seasonal statistical histograms using massive atmospheric data sets collected from 2010 to 2017 at four meteorological observatories. In order to estimate electromagnetic wave propagation characteristics in the presence of the duct atmosphere, we obtain and examine the path loss values by using the advanced refractive prediction system (AREPS) software applying the massive refractive index data set and the actual Korean coastal terrain data. These results are then fitted using Burr Type XII PDF curves to derive quantitative mean and variance values. To verify the suitability of the simulated path losses in the proposed analysis, the measurement of the path losses between Jeung‐do and Heuksan‐do are carried out in October 2017. The measurements and simulations of the autumn results are fitted by Burr Type XII CDF curves and agree well with each other. [ABSTRACT FROM AUTHOR]

In this communication, an electromagnetic boundary-value problem of modulated transverse corrugations in an infinite conducting circular cylinder is rigorously solved based on the Fourier transform, eigenfunction expansion, and the mode matching method. Radar cross section (RCS) of the modulated transverse corrugations is represented in the series form. Computation is performed to analyze scattering characteristics while varying depth, width, and period of the corrugations and to investigate the excitation of surface waves and concomitant RCS reduction. [ABSTRACT FROM AUTHOR]

The relationship between the threshold current density and the critical line length in eutectic SnPb and SnAgCu electromigrations were examined using solder lines with the various lengths ranging from 100 to 1000 μm. When the electron wind-force was balanced by the back-stress gradient force, the net flux of electromigration is zero, at which the current density and line length are defined as the threshold current density and the critical length, respectively. It was found that in SnAgCu electromigration, the 1/L dependence on the threshold current density showed good agreement, whereas the threshold current densities of the eutectic SnPb deviated from the 1/L dependence. The balance between the electron wind-force and the back-stress gradient force was the main factor determining the threshold product of SnAgCu electromigration. On the other hand, in the case of eutectic SnPb, the chemical driving force is contributed as a back-flux force in addition to the back-stress gradient force. The existence of the chemical driving force was caused by the nonequilibrium Pb concentration inside the Pb-rich phases between the cathode and anode during the electromigration procedure. [ABSTRACT FROM AUTHOR]

Hepatic lipid accumulation and apoptosis is elevated in patients with non-alcoholic steatohepatitis and is closely associated with severity. Saturated fatty acid palmitate stimulates lipid accumulation and apoptosis in hepatocytes. In the present study, we examined bee-bee tree oil (BO)-mediated protective effects on palmitate-induced lipid accumulation and apoptosis in mouse primary hepatocytes. Cells were cultured in a control media or the same media containing 150 or 300 µmol/L of albumin-bound palmitate for 24 h. BO concentrations used were 0, 0.1, 0.2, or 0.5%. Palmitate induced lipid accumulation and mRNA expression of lipogenic genes such as SREBP1c and SCD1. However, BO prevented these changes. Furthermore, palmitate stimulated caspase-3 activity and decreased cell viability in the absence of BO. BO reduced palmitate-induced activation of caspase-3 and cell death in a dose-dependent manner. AMP-activated protein kinase inhibitors abolished the effects of BO. Furthermore, BO suppressed palmitate-induced c-Jun N-terminal kinase (JNK) phosphorylation through the 5' adenosine monophosphate-activated protein kinase (AMPK)-dependent pathway. In conclusion, BO attenuated palmitate-induced hepatic steatosis and apoptosis through AMPK-mediated suppression of JNK signaling. These data suggest that BO is an important determinant of saturated fatty acid-induced lipid accumulation and apoptosis, and may be an effective therapeutic strategy for treatment of obesity-mediated liver diseases. [ABSTRACT FROM AUTHOR]

This study was undertaken to evaluate chemical characteristics and oxidative stability of tree-borne seed oils. A total of 15 different fatty acids were identified in six tree-borne seed oils, which included seven types of saturated fatty acids, four types of monounsaturated fatty acids, and four types of polyunsaturated fatty acids. Japanese camphor tree (JCT) had a high content of medium-chain fatty acids (97.94 ± 0.04%), in which fatty acid composition was distinct from those of the other five plant seed oils. Overall, contents of tocopherols, a type of fat-soluble vitamin, ranged between 3.82 ± 0.04 mg/100 g and 101.98 ± 1.34 mg/100 g, respectively. Phytosterol contents ranged from 117.77 ± 1.32 mg/100 g to 479.45 ± 4.27 mg/100 g, respectively. Of all tree-borne seed oils, β-sitosterol was the phytosterol at the highest concentration. Contents of unsaponifiables were between 0.13 ± 0.08 and 2.01 ± 0.02, and values of acid, peroxide, and p-anisidine were between 0.79 ± 0.01 and 38.94 ± 0.24 mg KOH/g, 3.53 ± 0.21 and 127.67 ± 1.79 meq/kg, and 2.07 ± 0.51 and 9.67 ± 0.25, respectively. Oxidative stability of tree-borne seed oils was assessed through measurement of oxidation-induction periods. These results should serve as a foundation to identify the potential of tree-borne seed oils in industrial application as well as in providing fundamental data. [ABSTRACT FROM AUTHOR]

In this paper, an analytical method for evaluation of via-plate capacitance including finite plate thickness in multilayer structures is proposed. An electrostatic boundary-value problem associated with a via in parallel plates is solved based on the Hankel transform and mode matching method, and thereby a fast-converging series-form expression for the via-plate capacitance is derived. The effect of finite plate thickness is taken into account by adopting the mode matching method instead of imposing an artificial perfect magnetic conductor boundary as in the previous works. We perform some computations to show the behaviors of the capacitance in terms of the via geometry, and they are validated through comparison with a static/quasi-static simulation, full-wave electromagnetic simulation, and the previous analytical solutions of via capacitance. [ABSTRACT FROM AUTHOR]

In this work, we present a dispersive finite-difference time-domain (FDTD) algorithm using a four-pole complex rational function (CRF). For the sake of a better curve fitting of the four-pole CRF dispersion model, we use a particle swarm optimization technique. We also discuss an efficient memory storage strategy using a state-space approach. The numerical aspects of four-pole CRF-FDTD, the numerical accuracy and the numerical stability, are investigated in detail. Numerical examples are used to validate four-pole CRF-FDTD and numerical stability issues are discussed in detail. We also discuss the computational accuracy and the computational efficiency of an arbitrary $N$-pole CRF-FDTD. [ABSTRACT FROM PUBLISHER]

Bacillus cereus contamination is a major food safety problem for Korean fermented soybean products, but few studies have assessed its potential to cause foodborne illness. The objectives of this study were to investigate the prevalence and characteristics of B. cereus isolated from Korean fermented soybean products. B. cereus was detected in 110 of 162 (67.9%) samples. The highest B. cereus frequency was observed in deonjang (68 of 93 samples, 73.1%) and cheonggukjang (18 of 25, 72.0%); however, nonhemolytic enterotoxin was detected only in 22 of 162 samples (13.6%). Although the tested B. cereus isolates showed diverse pulsotypes according to repetitive sequence-PCR banding patterns, they displayed similar antibiotic sensitivity spectra. The low frequency of enterotoxin detection suggests that the potential risk of B. cereus foodborne illness associated with Korean fermented soybean products is lower than generally presumed. However, considering the prevalence of B. cereus and the high content of fermented soybean products in the Korean diet, it is necessary to constantly monitor the level of contamination with B. cereus and its toxins in such Korean food products. [ABSTRACT FROM AUTHOR]

Abstract: Bacillus cereus can cause the diarrheal and emetic type of food poisoning but the symptoms of emetic food poisoning caused by B. cereus occasionally include emesis and diarrhea. The enterotoxin characteristics of emetic toxin (cereulide) producing B. cereus were needed to be determined. Therefore, forty B. cereus strains isolated from various sources in Korea were investigated for the presence of enterotoxin genes. All strains were confirmed to produce the emetic toxin using HPLC-MS methods. The rates of the nheABC, hblCDA, entFM and cytK genes amongst emetic toxin producing B. cereus strains were 82.5, 7.5, 50.0 and 27.5%, respectively. Pattern III harbored nheABC and entFM genes and pattern V processed entFM gene and were shown to be the major patterns, being present in 55.0% (21 of 40) of the emetic toxin producing B. cereus strains. Our findings revealed that 34 (85.0%) of 40 emetic toxin producing B. cereus strains isolated in Korea have the potential to cause diarrheal and emetic type of food poisoning, simultaneously. Thus, emetic toxin and enterotoxin genes should be constantly screened to provide insight into B. cereus food poisoning. [Copyright &y& Elsevier]

Bacillus cereus was divided into emetic toxin (cereulide)- and enterotoxin-producing strains, but emetic toxin-producing B. cereus is difficult to detect immunochemically. Screening methods for emetic toxin-producing B. cereus are needed. The objectives of this study were to identify and detect emetic toxin-producing B. cereus among 160 B. cereus strains, and to compare enterotoxin production and phenotypic characteristics between the emetic toxin-producing and enterotoxin-producing strains. Forty emetic toxin-producing B. cereus strains were determined with high-pressure liquid chromatography-mass spectrometry analysis. Among the emetic toxin-producing strains (n = 40), 31 (77.5%) and 3 (7.5%) strains produced nonhemolytic enterotoxin (NHE) and hemolysin BL (HBL) enterotoxins, respectively. In addition, 107 (89.2%) and 100 (83.3%) strains produced NHE and HBL enterotoxins among the enterotoxin-producing strains (n = 120). The number of strains positive for starch hydrolysis, salicin fermentation, and hemolysis among the emetic toxin-producing strains were 3 (7.5%), 3 (7.5%), and 26 (65.0%), respectively, and among enterotoxin-producing strains, these numbers were 101 (84.2%), 100 (83.3%), and 111 1 (92.5%), respectively. In particular, the three emetic toxin-producing B. cereus strains (JNHE 6, JNHE 36, and KNIH 28) produced the HBL and NHE enterotoxins and were capable of starch hydrolysis and salicin fermentation. The absence of HBL enterotoxin and certain phenotypic properties, such as starch hydrolysis and salicin fermentation, indicates that these properties were not critical characteristics of the emetic toxin-producing B. cereus tested in this study. [ABSTRACT FROM AUTHOR]

This paper proposes the algorithm to control the current ratio of the transmitting (Tx) coils for proper power distribution to the two receiving (Rx) coils in wireless power transfer (WPT) system. The proposed algorithm assumes that each Rx coil appears at different times to consider the situation where multiple users request power transmission as practically as possible. That is, suppose the second Rx coil enters the charging space later than the first Rx coil. When each coil enters the charging space, only the Tx coil is used to obtain the value required for calculation. Using the obtained result, the optimized Tx coil current is calculated by the proposed algorithm and proper power distribution to both Rx coils is achieved. Three Tx coils and two Rx coils are constructed using the ANSYS MAXWELL simulation tool. As a result of applying the proposed algorithm, it was confirmed that a similar level of power was transmitted between 40∼60%, respectively. The sum of the power transmitted to the two Rx coils also appeared as more than 75%. [ABSTRACT FROM AUTHOR]