• Korean Journal of Applied Biomechanics
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• v.25 no.3
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• pp.257-263
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• 2015

Objective : The purpose of this study was to investigate the effect of genu valgum on the body mass index, movement of lower limb joints, and ground reaction force. Methods : Gait patterns of 30 college students with genu valgum were analyzed and the static Q angle of the femur was measured for selecting genu valgum of the subjects. To analyze the kinetic changes during walking, the six-camera Vicon MX motion analysis system was used. The subjects were asked to walk 12 meters using the more comfortable walking method for walking. After they walked 12 meters more than 10 times, their most natural walking patterns were chosen three times and analyzed. Results : As a result of measuring a relationship between genu valgum and Q-angle, as the Q-angle increases, it showed a genu valgum also increased. Body Mass Index showed a significant difference between the groups was higher in the genu valgum group.(p<.001). The analysis result showed that genu valgum had a significant effect on the internal rotation moment in the hip joint(p<.05). Also, genu valgum had a significant effect on the internal rotation moment of the knee joint(p<.05). The comparative analysis of the Medial-Lateral ground reaction force in the genu valgum group showed a tendency to increase the medial ground reaction force(p<.05). The vertical ground reaction forces of the middle of the stance phase(Fz0) showed a significant increase in genu valgum group(p<.05), in particular the results showed a decrease in the early stance phase(p<.001). Conclusion : In conclusion, the change in body mass is considered to be made by proactive regular exercise for improvement of the genu valgum. In addition, the prevention of the deformation caused by secondary of the genu valgum in this study may be used as an indicator of the position alignment rehabilitation for structural and functional improvements. Applying a therapeutic exercise program for the next lap will require changes in posture alignment.

• Analytical Science and Technology
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• v.15 no.5
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• pp.433-438
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• 2002

Trace elements in two air filters (V-50, P-50) artificially loaded with urban dust provided from IAEA were determined non-destructively using instrumental neutron activation analysis. Standard reference material (Urban Particulate Matter, SRM 1648) of National Institute of Standard and Technology was used for analytical quality control. About 20 elements in both of loaded filter samples were determined. To evaluate inter-laboratory comparison and proficiency test, analytical data were statistically treated with the results which collected from 49 laboratories, 40 countries participated in this study using neutron activation analysis, particle induced X-ray emission, inductively coupled plasma mass spectroscopy, etc,. From the results of statistical treatment, Z-scores are within ${\pm}2$. Furthermore, accuracy and precision of obtained analytical values are passed according to the criteria of the proficiency test. Consequently, it was proved that analytical quality for air dust samples being performed has been controlled properly.

• Analytical Science and Technology
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• v.15 no.2
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• pp.120-126
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• 2002

The analytical performance of four commercially-available pneumatic nebulizers(Meinhard, Cross-flow, Babington, ESI PFA) was evaluated using inductively coupled plasma-atomic emission spectrometry (ICP-AES) and ICP-mass spectrometry (ICP-MS) instruments. The performance of an inert concentric nebulizer and a modified conespray nebulizer, made in Korea Research Institute of Standards and Science (KRISS), is compared with that of the four commercial nebulizers. Variation of sample introduction efficiency was investigated as carrier argon pressure and sample uptake rate were changed. Variation of sensitivity, signal stability, blank intensity and oxide/hydride ratios were also studied when the nebulizers were connected to the ICP-MS and ICP-AES instruments. It was found that good analytical result such as high sensitivity, low blank, stable signal and so on can be obtained with judicious selection of the nebulizer depending on the type of sample, sample amount, type of analytical instrument and analyte.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.7
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• pp.827-833
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• 2011

In this study, a simulation model to estimate the current-collection performance of a high-speed train was developed by using a commercial finite element analysis software, SAMCEF. A three-dimensional springDdamperDmass model of a pantograph was created, and its reliability was validated by comparing the receptance of the model to that of the actual pantograph. The wave propagation speed of the catenary model was compared with the analytical wave propagation speed of the catenary system presented in the UIC 799 OR standard. The length of the droppers was controlled, and the pre-sag of the contact wire due to gravity was considered. The catenary and the pantograph were connected by using a contact element, and the contact force variation when the pantograph was moved at velocities of 300 km/h and 370 km/h was obtained. The average, standard deviation, maximum, and minimum values of the contact force were analyzed, and the effectiveness of the developed simulation model was examined.

• Journal of Korea Water Resources Association
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• v.32 no.3
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• pp.215-223
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• 1999

Recently, measurement of soil moisture contents using TDR (time domain reflectometry) has been proven to be viable technique. The first empirical model proposed by Topp et al. (1980) has been widely used to determine moisture contents of soils from the TDR-measured dielectric constants. However, applicability of the model was limited to medium-textured soils. In this study, we investigate the applicability of the model to sandy-gravelly soils. Calibration experiments consisted of measurement on travel time of electromagnetic waveform along the parallel TDR rods inserted into samples and gravimetric determination of soil moisture contents. The experiments are performed for two sets of samples different in the length and each set consisted of seven different particle size distributions with various gavel contents. The calibration results show that the Topp equation overestimated the measured moisture content for a given dielectric constant by 3 to 8%. We therefore propose new empirical relationships valid for sandy-gravelly soils.

• Korean Journal of Materials Research
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• v.1 no.4
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• pp.214-220
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• 1991

The effects of $SiO_2$ reactive ion etching (RIE) in $CHF_{3/}C_2F_6$ on the surface properties of the underlying Si substrate were studied by X-ray photoelectron spectroscopy(XPS) and secondary ion mass spectrometry(SIMS) techniques. Angle-resolved XPS analysis was carried out as non-destructive depth profile one for investigating the chemical bonding states of silicion, carbon, oxygen and fluorine. The residue layer consists of C-F polymer. O-F bond was found on the top of the polymer layer and Si-O, Si-C and Si-F bonds were detected between Si substrate and polymer film. A 60nm thick damaged layer of silicon surface mainly contains carbon and fluorine.

• The Journal of the Acoustical Society of Korea
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• v.24 no.3
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• pp.160-165
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• 2005

We have developed SH (shear horizontal) surface acoustic wave (SAW) sensors for detection of the immobilization and hybridization of DNA (deoxyribonucleic acid) on the gold coated delay line of transverse SAW devices. The experiments of DNA immobilization and hybridization were performed with 15-mer oligonucleotides (probe and complementary target DNA). The sensor consists of twin SAW delay line oscillators operating at 100 MHz fabricated on $36^{\circ}$ rotated Y-cut $LiTaO_3$ piezoelectric single crystals. The relative change in the frequency of the two oscillators was monitored to detect the hybridization between target DNA and immobilized probe DNA in pH 7.4 PBS (phosphate buffered saline) solution. The measurement results showed a good response of the sensor to the mass loading effects of the DNA immobilization and hybridization with the sensitivity up to $1.55{\cal}ng/{\cal}ml/Hz$.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.20 no.8
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• pp.526-533
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• 2008

In this study, theoretical super screen vibration analysis has been carried out to predict the dynamic characteristics of interactive waste particles. In order to approach these problems, it is necessary to have a fundamental understanding the screening process and the process of both the remaining and the passed material on a screen with several interacting screen planes based on Soldinger(1999) was discussed. Here, the vibrating screen is composed of three assemblies such as screen, wastes guide, and supported screen as shown in Fig. 1. This model is regarded vibrator as the system of screen fixed tilt plates. Then materials(or particles) of different size is to be separated by using the eccentric vibrator and classifying tilt plates. As well moisturized construction wastes is more efficient to separate than moisture-less it. In processing separate mechanism, the more materials is light, the more staying time is long. Thus much lighter construction wastes(wood, Styrofoam, etc) and heavier materials are separated by staying time delay in a super screen. The design results, separation screen were able to know that small and larger particles are conspicuous difference each motion character according to trajectory particles, and small particles raise the probability in classifying tilt plates.

• Elastomers and Composites
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• v.47 no.3
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• pp.210-215
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• 2012

Whitening phenomena of the EPDM composites with different inorganic filler compositions which were aged at $90^{\circ}C$ for 7 days in air and tap water atmospheres, respectively, were investigated. The aged samples in tap water containing stearic acid exhibited severe whitening phenomena, while all the samples aged in air did not show any whitening. Depending on the filler compositions, there was no big difference in the whitening phenomena. The whitening materials were analyzed using gas chromatography/mass spectrometry (GC/MS), image analysis, energy-dispersive X-ray spectroscopy (EDX), and attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR). The whitening materials were identified to be salts of stearic acid. The salts of stearic acid were formed by reaction of metal cation in tap water and stearic acid in the sample.

• Korean Journal of Food Science and Technology
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• v.31 no.1
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• pp.1-6
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• 1999

A piezoelectric (PZ) biosensor system detecting Salmonella spp. was developed. The system consisted of an oscillator, a frequency counter and an antibody-immobilized quartz crystal. An anti-Salmonella antibody was immobilized on one gold. surface of the quartz crystal with protein A. Salmonella detection was made by measuring resonant frequency shift owing to a mass change by specific binding of microbial cells to the gold surface of the PZ crystal. The PZ antibody sensor was operated optimally at 0.1M phosphate buffer, pH 7.2 and $35^{\circ}C$. The sensor was quite specific to Salmonella spp. The obtained frequency shift was correlated with the Salmonella concentration in the range of $10^5{\sim}10^6\;CFU/mL$. The frequency shift increased further by addition of polystyrene beads. The Salmonella detection which is indicated by a steady-state microbial adsorption to the quartz crystal was accomplished within 50min.