• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.10
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• pp.1964-1972
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• 2017

K-water have been operating as an International accredited calibration organization for ISO 17025 regarding float, ultrasonic and radar type since 2008. Due to the absence of on-site calibration system, water level meter could only be calibrated from a laboratory. Therefore K-water institute developed an mobile calibration system for water-level meter in 2015 to calibrate the water-level meter on site. The mobile calibration system was certificated by KOLAS(Korea Laboratory Accreditation Scheme) in 2016. In this paper a mobile calibration system, which is a method to calibrate float type water level meter on site, is established. A mathematical equation was derived by reviewing characteristics of standard equipment and measurement. By developing the mobile calibration system, it is possible to achieve reliability of data through scientific system operation on hydrological data.

• Journal of Conservation Science
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• v.29 no.2
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• pp.93-102
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• 2013

The wooden Ksitigarbha Triad Statues (Treasure No. 1749) of Shinhungsa temple in Sokcho are enshrined in the inside of the Myeonbujeon Hall. The Statues are highly damaged physical weathering which are crack and exfoliation. Also, the Statues were deteriorated by chemical and biological weathering. This study carried out nondestructive method as deterioration map, ultrasonic measurement, X-ray and endoscopy survey for deterioration evaluation and conservation plan. As a result, Ksitigarbha Statue coated by dust and various pollutants. And gold-gilt of Statue's surface has peeled off. Head part of Mudokguiwang Statue was discolored from water leak in Myeongbujeon Hall. Domyeongjonja Statue is highly damaged by insects. Result of endoscopy, there were bee hives in the inside of the Statue. Therefore, we suggest that these Statues have need to do conservation treatment on the basis of diagnostic results.

• Journal of the Korean Vacuum Society
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• v.12 no.3
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• pp.157-161
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• 2003

Nowadays there are increasing demands for more accurate measurement of atmospheric pressure according to the development of environmental industries. One of the most important pressure gauges for satisfying these demands is a quartz resonance barometer. In order to calibrate such an accurate barometer, laser/ultrasonic mercury manometers have been used. However, complexity and cost of mercury manometers made it out of use gradually. As a substitute, a gas-operated pressure balance is used for calibration of precise barometers. In such a case, commercially available pressure balances cannot be entirely suitable because consequent exposure of the piston, cylinder and masses to the atmosphere causes the problem of contamination. In this paper a device for changing the masses in situ without breaking the vacuum is described. This device made it possible to add or remove weights in the absolute mode, thereby greatly reducing the time between observations. At the same time, we investigated the characteristics of a commercial precise barometer using this new apparatus.

• Journal of the Korean Vacuum Society
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• v.12 no.3
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• pp.151-156
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• 2003

Two capacitance diaphragm gauges(CDG) and two resonance silicon gauges(RSG) were calibrated using an ultrasonic interferometer as a national low vacuum standard in KRISS. The CDG has superior pressure resolution and is rugged as well as resistant to over-pressure because of all-metal inner components. Meanwhile, the RSG is a new type of MEMS sensor that has excellent calibration stability and is resistant to mechanical shocks. The calibration uncertainties were analyzed according to the ISO procedures. Results showed that the maximum difference of the expanded uncertainties was $9\times10^{-3}$Pa at the generated pressure of 100 Pa for the two different types. It is remarkable that the RSG can be used as a transfer standard at low vacuum since their accuracies were found to be within 0.5 %.

• Wind and Structures
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• v.31 no.3
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• pp.269-285
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• 2020

The statistical characteristics of typhoon wind speed records tend to have a considerable time-varying trend; thus, the stationary wind model may not be appropriate to estimate the wind characteristics of typhoon events. Several nonstationary wind speed models have been proposed by pioneers to characterize wind characteristics more accurately, but comparative studies on the applicability of the different wind models are still lacking. In this study, three landfall typhoons, Ampil, Jongdari, and Rumbia, recorded by ultrasonic anemometers atop the Shanghai World Financial Center (SWFC), are used for the comparative analysis of stationary and nonstationary wind characteristics. The time-varying mean is extracted with the discrete wavelet transform (DWT) method, and the time-varying standard deviation is calculated by the autoregressive moving average generalized autoregressive conditional heteroscedasticity (ARMA-GARCH) model. After extracting the time-varying trend, the longitudinal wind characteristics, e.g., the probability distribution, power spectral density (PSD), turbulence integral scale, turbulence intensity, gust factor, and peak factor, are comparatively analyzed based on the stationary wind speed model, time-varying mean wind speed model and time-varying standard deviation wind speed model. The comparative analysis of the different wind models emphasizes the significance of the nonstationary considerations in typhoon events. The time-varying standard deviation model can better identify the similarities among the different typhoons and appropriately describe the nonstationary wind characteristics of the typhoons.

• Korean Journal of Digital Imaging in Medicine
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• v.16 no.2
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• pp.1-7
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• 2014

This study is to increase the accuracy of the diagnosis of benign prostatic hyperplasia by presenting a method that can accurately measure the residual urine amount of the bladder by using an ultrasound image. Agar powder, Propanol and distilled water were used as materials for making a phantom. In order to measure the volume, a $10m{\ell}$ cylinder, syringe and beaker were used. The image was obtained by scanning phantoms produced into six shapes. Each constant value was obtained by using the expression designed to measure the residual urine amount of the bladder and was compared and analyzed. The measuring method of Bladder volume was presented and a constant value for each shape was obtained and five observers measured it five times. According to the results of clinical application, the errors of Ellipse-beanbag, Shield-shield were 11.0%, 18.2%, respectively. Constant values depending on the shape of each phantom were presented in order to accurately measure the volume of the bladder in measuring the amount of residual urine for the diagnosis of benign prostatic hyperplasia. The accuracy of the volume using this was verified statistically(p > 0.05). Therefore, it is considered to be useful in diagnosing benign prostatic hyperplasia by using the ultrasound imaging measuring method presented.

• International Journal of Aeronautical and Space Sciences
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• v.4 no.1
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• pp.63-74
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• 2003

The vortical flow of a 65-deg flat plate delta wing with a leading edge extension(LEX) was examined through off-surface visualization, 5-hole probe and hot-film measurements. The off-surface flow visualization technique used micro water droplets generated by a home-style ultrasonic humidifier and a laser beam sheet. The angles of attack ranged from 10 to 30 degrees, and the sideslip angles ranged from 0 to -15 degrees. The Reynolds number was $1.82{\times}10^5$ for the flow visualization, and $1.76{\times}10^6$ for the 5-hole probe and hot-film measurements. The comparison of the visualization photos and the flow field measurement showed that the two results were in a good agreement for the relative position and the structure of the wing and LEX vortices, even though the flow Reynolds numbers of the two results were much different. The wing vortex and the LEX vortex coil each other while maintaining a comparable strength and identity at zero sideslip. Neither a looping of the wing vortex around the strake vortex, nor the lopsided coiling of the stronger strake and the weaker wing vortices was observed. At non-zero sideslip, the downward movement of the LEX vortex when going downstream was enhanced on the windward side, and the downward and inboard movement of the LEX vortex when going downstream was suppressed on the leeward side. The counterclockwise coiling of the wing and LEX vortices was decreased significantly on the leeward side.

• Journal of the Korean Ceramic Society
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• v.54 no.2
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• pp.150-157
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• 2017

Three types of piezoelectric single crystals [PMN-PT (Generation I $[Pb(Mg_{1/3}Nb_{2/3})O_3-PbTiO_3]$), PMN-PZT (Generation II $[Pb(Mg_{1/3}Nb_{2/3})O_3-Pb(Zr,Ti)O_3]$), PMN-PZT-Mn (Generation III)] were grown by the solid-state single crystal growth (SSCG) method, and their dielectric and piezoelectric properties were measured and compared. Compared to (001) PMN-PT and PMN-PZT single crystals, the (001) PMN-PZT-Mn single crystals exhibited a higher transition temperature between the rhombohedral and tetragonal phases ($T_{RT}=144^{\circ}C$), as well as a higher coercive electric field ($E_C=6.3kV/cm$) and internal bias field ($E_I=1.6kV/cm$). The (011) PMN-PZT-Mn single crystals showed the highest coercive electric field ($E_C=7.0kV/cm$), and the highest stability of $E_C$ and $E_I$ during 60 cycles of polarization measurement. These results demonstrate that both Mn doping (for higher electromechanical quality factor ($Q_m$)) and a (011) crystallographic orientation (for higher coercive electric field and stability) are necessary for high power transducer applications of these piezoelectric single crystals. Specifically, the (011) PMN-PZT-Mn single crystal (Gen. III) had the highest potential for application in the fields of SONAR transducers, high intensity focused ultrasound (HIFU), ultrasonic motors, and others.

• Clinical and Experimental Reproductive Medicine
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• v.20 no.1
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• pp.37-43
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• 1993

In 27 patients with the past history of poor response to the gonadotropin superovulation induction due to poor follicular growth or permature surge of endogenous luteinizing hormone, the effectiveness of pituitary supperssion with the gonadotropin releasing hormone agonist(GnRH-a) in in vitro fertilization(IVF) program was evaluated in 43 cycles using a combination regimen of D-Trp-6 LHRH(Decapeptyl, Ferring)and FSH/hMG from June, 1989 to August, 1990 at Korea University Hospital IVF Clinic. At midluteal phase of menstrual cycle, Decapeptyl-CR was administered by long-term protocol to minimize initial agonistic effect of endogenous gonadotropins. After the confirmation of pituitary suppression, about 2-3 weeks after GNRH-a administration, ovarian follicle growth was stimulated with FSH/hMG and followed by transvaginal ultrasonic measurement of follicle size and by monitoring of serm E2 and LH if necessary. When compared with the control group stimulated with gonadotropin regimen only, the cancellation rate and occurrence rate of premature LH surge during gonadotropin treatment were significantly lower in study group(11.6% and 2.4%, respectively). There is no significant differences in the mean number of aspirated oocytes, fertilization/cleavage rate, embryo transfer(ET) rate, and mean number of embryos transferred between the two groups. The pregnancy rate per treatment cycle, 16.3%, and per ET cycle, 23.3%, were significantly higher in the study group compared with those of control group. These data suggest that GnRH-a therapy is effective for previous poor responder In gonadotropin superovulation induction for IVF.

• Korean journal of food and cookery science
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• v.33 no.3
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• pp.256-263
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• 2017

Purpose: Essential oils are secondary metabolites of herbs and have antibacterial activities against foodborne pathogens. However, their applications for food protection are limited due to the hydrophobic and volatile natures of essential oils. Methods: In this study, essential oil nanoemulsions of rosemary and lavender were formulated with non-ionic surfactant Tween 80 and water using ultrasonic emulsification, and their antibacterial effects were determined. Results: The antibacterial activities of nanoemulsions were evaluated against 12 strains of 10 bacterial species, and significant antibacterial effects were observed against four Gram-positive and four Gram-negative bacteria but not against Streptococcus mutans and Shigella sonnei. In the disc diffusion test, the diameter of the inhibition zone proportionally increased with the concentration of nanoemulsions. Using cell turbidity measurement, minimum bactericidal concentration (MBC) of the nanoemulsions, which is the lowest concentration reducing viability of the initial bacterial inoculum by ${\geq}99.9%$, was significantly higher than the minimum inhibitory concentration (MIC) of the nanoemulsions. The largest bactericidal effects of lavender and rosemary essential oil nanoemulsions were observed against S. enterica and S. aureus, respectively. Conclusion: Nanoemulsion technique could improve antibacterial activity of essential oil nanoemulsions by increasing the solubility and stability of essential oils. Our findings shed light on the potential use of essential oil nanoemulsions as an alternative to chemical sanitizers in food protection.