• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.24 no.5
• /
• pp.534-540
• /
• 2013

Interest of the hand effect on the electromagnetic wave are internationally increasing with the increase of the use of the mobile phone. IEC TC106(International Electrotechnical Commission, Technical Committee 106) promotes international research exchange program in order to reflect the effect of human hands in the standard assessment method of human exposure dosimetry by the electromagnetic wave of mobile phones. Since current commercialized hand phantom is manufactured by taking into account the average size of westerners and provides only one grip posture, it imposes many restrictions on the accurate SAR measurement. Therefore, the development of proper hand phantom accounting for domestic situation and various grip posture capability is essential in order to analyze the accurate effect of human hand on the exposure estimation. In this paper, a jelly hand phantom suitable for Korean was manufactured with various grip posture capability at 835 MHz and 1,800 MHz bands. Although the tolerances of permittivity and conductivity of the manufactured hand phantom are with ${\pm}10%$ each, it was much less than CTIA(Cellular Telecommunication Industry Association) tolerance of ${\pm}20%$ at both bands. Its 3D CAD(3 Dimensional Computer Aided Design) file which was developed can be utilized for the simulation of human hand effect on SAR measurement of mobile phones. The findings in this study can be utilized for the analysis of human hand effect on SAR measurement of a mobile phone.

• The Journal of the Korea Contents Association
• /
• v.10 no.5
• /
• pp.343-350
• /
• 2010

We measured the radiation exposure for 55 persons (male: 36, female: 19) who was diagnosed with kidney and ureter stones and received ESWL. The absorbed dose was measured at the organ which is expected to absorb relatively much radiation (kidney, bladder, liver). The radiation dose measurement voltage 80kVp, current of 5mA as a fixed model of the human body by using the Rando phantom with Radiophotoluminescent Glass Dosimeter. Absorbed dose was measured for two times (5 minute and 10 minute, each) and converted to effective dose. Mean number of treatment was 1.8 times (1~4) per patient was the mean time of radiation exposure533 seconds (248-2516). For the treatment of right renal stone, the effective dose of right kidney, left kidney, liver and bladder was 2.458mSv, 0.152mSv, 1.404 mSv and 0.019mSv, respectively. For the treatment of left renal stone, the effective dose of right kidney, left kidney, liver and bladder was 2.496mSv, 0.252mSv, 0.178 mSv, and 0.017mSv, respectively. For the treatment of distal ureter stone, the effective dose of right kidney, left kidney and bladder was 0.009mSv, 0.01mSv and 3.742mSv, respectively.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.30 no.9
• /
• pp.535-540
• /
• 2017

The changes in the electrical characteristics of CMOS ICs due to coupling with a narrow-band electromagnetic wave were analyzed in this study. A magnetron (3 kW, 2.45 GHz) was used as the narrow-band electromagnetic source. The DUT was a CMOS logic IC and the gate output was in the ON state. The malfunction of the ICs was confirmed by monitoring the variation of the gate output voltage. It was observed that malfunction (self-reset) and destruction of the ICs occurred as the electric field increased. To confirm the variation of electrical characteristics of the ICs due to the narrow-band electromagnetic wave, the pin-to-pin resistances (Vcc-GND, Vcc-Input1, Input1-GND) and input capacitance of the ICs were measured. The pin-to-pin resistances and input capacitance of the ICs before exposure to the narrow-band electromagnetic waves were $8.57M{\Omega}$ (Vcc-GND), $14.14M{\Omega}$ (Vcc-Input1), $18.24M{\Omega}$ (Input1-GND), and 5 pF (input capacitance). The ICs exposed to narrow-band electromagnetic waves showed mostly similar values, but some error values were observed, such as $2.5{\Omega}$, $50M{\Omega}$, or 71 pF. This is attributed to the breakdown of the pn junction when latch-up in CMOS occurred. In order to confirm surface damage of the ICs, the epoxy molding compound was removed and then studied with an optical microscope. In general, there was severe deterioration in the PCB trace. It is considered that the current density of the trace increased due to the electromagnetic wave, resulting in the deterioration of the trace. The results of this study can be applied as basic data for the analysis of the effect of narrow-band high-power electromagnetic waves on ICs.

• Journal of the Korean Society for Nondestructive Testing
• /
• v.24 no.5
• /
• pp.518-524
• /
• 2004

The feasibility of Y(z) curve method of scanning acoustic microscope using high frequency transducer was experimentally studied for assessment of the thermal degradation in Co-based superalloy. Thermal degradation was performed to simulate the microstructural changes in Co-based superalloy arising from long term exposure at high temperature. Longitudinal wave velocity measured by pulse echo method using 10MHz transducer and leaky surface acoustic wave (LSAW) velocity measured by V(z) curve method using 200MHE transducer were measured to investigate the effect on thermal degradation. Ultrasonic velocity decreased as the aging time increased in both ultrasonic waves. Moreover, the low frequency longitudinal wave velocity decreased a little. Otherwise, the high frequency LSAW velocity drastically decreased up to a maximum of 4.7% at the aging time of 4,000hours. A good correlation was found between LSAW and Vickers hardness. Consequently, V(z) curve method of SAM using high frequency transducer could be a potential tool for assessing thermal degradation.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.16 no.5 s.96
• /
• pp.511-517
• /
• 2005

Many cellular phone volunteer studies have been conducted since such a social issue is raised that the long time usage of cellular phone by teenagers may increase health risk. While there were various adult volunteer studies using GSM cellular phone on heart rate and blood pressure, very few teenager studies using CDMA phone were conducted. In this study, two volunteer groups of 21 teenagers and 21 adults were exposed to 300 mW CDMA wave for half an hour, and the physiological parameters such as blood pressure, heart rate, respiration rate, and skin impedance were investigated. All the parameters fur both groups were unaffected during exposure except the skin impedance of teenager group.

• Biomedical Science Letters
• /
• v.12 no.1
• /
• pp.9-16
• /
• 2006

We investigated the effects of 835-MHz electromagnetic field (EMF), one of the most popular communication frequency band in Korean code-division multiple-access (CDMA) mobile phone system, on cellular signal transduction. For this, we examined the change of intracellular calcium $([Ca^{2+}]_i)$, reactive oxygen species (ROS) and F-actin polymerization after exposure to 835-MHz EMF followed by the treatment of agonists in Rat-2 fibroblast cells. Culture cells were pretreated with serum-tree medium and concomitantly exposed to 835-MHz at specific absorption rate (SAR) of 4.0 W/kg for 24 hr in a specialized designed apparatus based on Transverse Electro Magnetics (TEM) wave theory. Intracellular $Ca^{2+}$ responses to lysophosphatidic acid (LPA) and epidermal growth factor (EGF) in Rat-2 fibroblast after exposure to 835-MHz EMF were shown to be similar pattern as observed in normal cultured cells. However, the LPA-induced calcium spiking was slightly delayed to 7 sec and sustained thereafter to a little higher ground level under 835-MHz EMF radiation compared to unexposed cells. ROS production level by LPA in the exposed cells was not different from that in control. Furthermore, LPA induced the production of stress fibers with no significant difference in the exposed and unexposed cells. These results suggest that mobile phone radiation (835-MHz, SAR 4.0 W/kg) may not be directly related to signal transduction in Rat-2 fibroblasts except the slight effect of calcium spiking in LPA-induced cells but remain to be further elucidated for possible indirect intervention.

• Korean Journal of Human Ecology
• /
• v.17 no.6
• /
• pp.1215-1224
• /
• 2008

This research has measured the indoor environment of thirty hair salons, which are located on Gunsan-Si, Jeonlabbuk-Do, from April 1st to April 30th 2005, to examine the related factors on a work environment of hairdressers and a revelation of respiratory symptom, and has polled 260 hairdressers and 350 office workers. After measuring the physical environment of hair salons, the room temperature, the relative humidity and the illumination was in an agreeable range, and 60 percent of hair salons depended on the natural ventilation through the windows. The levels of acetone, toluene and xylene, which were measured at the hair salons, were all under the safety standards (p<0.05), but these are still harmful and volatile matters, so they can be bad for your health by the contact of skin and respiration. The harmful factors that affect a revelation of respiratory symptom were the group who has many exposures of permanent wave or bleaching/dyeing and not many experiences of hairdressing work, the group who smokes every day, and the group who never exercises at all (p<0.05). This result shows that there are possibilities of health problem for hairdressers from the constant and repeating hairdressing works with the exposure of chemicals such as the permanent, bleaching and dyeing. so that hairdressers recognize that they need appropriate ventilation facilities for their agreeable indoor-environments. And also, to prevent the direct exposure of chemicals as much as they can, they need to have an active management of an individual health care by wearing gloves, mask or something like that.

• Journal of the Korea Fashion and Costume Design Association
• /
• v.8 no.1
• /
• pp.155-168
• /
• 2006

The purpose of this study focusing on the gather decorations shown in the modern fashion was to review needlework techniques and design features of gather decorations and thereupon, analyze the aesthetic characteristics of gather decorations shown in designers' works to examine the gather decoration trend in today's fashion. First, the decorative features of gather decorations different from the conventional costumes are shirring, lace and trimming combined or shirring repeated. Second, in view of sensualism, the gather decorations seem to play a role of enhancing the exposure as a mode of expression, while the indirect exposure or beach is mixed with the materials to widen the range of gather decoration expressions. Third, in terms of history, the conventional decorative techniques are combined with new techniques and materials to create a fantastic and romantic mood different from the conventional costumes. Fourth, in view of rhythms, the wave line of the rim for gather decorations serves to express some vivid effects; on the human body, its monotonous plane repetition will turn into a new expression or a voluminous physical sense of motion. However, since expressions or meanings of the gather decorations are much diversified, they should not be regarded as simple decoration details. Our modern designers searching for new expression of creases use unique structural forms to explore the possibility of creative gather decorations. In all, since gather decorations seem to be significant as unique details conducive to a structural pragmatism and aesthetics, it is deemed necessary to continue to develop gather decorations.

• The Journal of the Petrological Society of Korea
• /
• v.23 no.3
• /
• pp.261-272
• /
• 2014

Over the last three decades, advances in AMS (Accelerator Mass Spectrometry) and Noble Gas Mass Spectrometer make various application of terrestrial cosmogenic nuclides (CNs) to wide range of earth surface sciences possible. Dating techniques can be divided into three sub-approaches: simple surface exposure dating, depth-profile dating, and burial dating, depending on the condition of targeted surfaces. In terms of Korean landscape view, CNs dating can be applied to fluvial and marine terrace, alluvial fan, tectonic landform (fault scarp and faulted surfaces), debris landforms such as rock fall, talus, block field and stream, lacustrine and marine wave-cut platform, cave deposits, Pliocene basin fill and archaeological sites. In addition, in terms of lithology, the previous limit to quartz-rich rocks such as granite and gneiss can be expanded to volcanic and carbonate rocks with the help of recent advances in CNs analysis in those rocks.

• Journal of Biosystems Engineering
• /
• v.33 no.6
• /
• pp.404-409
• /
• 2008

Excessive presence of heavy metals in environment affects plants and fruits grown in the contaminated area. Rapid on-site monitoring of heavy metals can provide useful information for efficiently characterizing heavy metal-contaminated sites and for minimizing the exposure of the contaminated food crops to humans. This study reports on the evaluation of gold and glassy carbon (GC) electrodes with mercury or bismuth as a coating material for simultaneous determination of cadmium (Cd) and lead (Pb) in 0.1 M $HNO_3$ solution by anodic stripping voltammetry (ASV). The use of a square-wave voltammetric potential between a working electrode and a reference electrode caused Cd and Pb ions deposited on the electrode surface to be oxidized, thereby generating electric currents at different potentials. The mercury-coated gold electrode was not sensitive enough to detect the usable range of Cd concentrations (1 to 100 ppb). The GC electrodes with mercury or bismuth displayed well-defined, sharp and separate current peaks for Cd and Pb ions when the square-wave voltammetric potentials were applied. The peak currents measured with both mercury- and bismuth- coated GC electrodes were linearly proportional to Cd and Pb concentrations in the range of 1 to 200 ppb in 0.1 M $HNO_3$ with strong linear relationships between concentration and peak current ($R^2$ > 0.95), indicating that both of Cd and Pb ions could be quantitatively measured.