• Proceedings of the KIEE Conference
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• 2003.07a
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• pp.455-457
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• 2003

In the present IEC 60427(2000), reduced applied voltage can be used for synthetic short-circuit making current tests if the maximum pre-arcing time of the test circuit breaker is less than $1/{\omega}$. But in the near future IEC, only the making tests with full test voltage shall be allowed. To meet this trend, KERI is preparing synthetic making test facilities using step-up transformer, ITMC and plasma making switch. This paper presents analytical characteristics of KERI's synthetic short-circuit making test circuits. The results of this paper can be useful for effective and adequate tests.

• Analytical Science and Technology
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• v.21 no.6
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• pp.526-534
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• 2008

To determine the trace level of synthetic and natural hormones in food, the improvement of official analytical method and new development of simultaneous determination of hormones were established. On the basis of developed analytical method, the background level of natural hormones and distribution of residual hormones were monitored in meat. Target hormones were six natural hormones such as estrogens ($17{\beta}$-estradiol, $17{\alpha}$-estradiol, estrone), androgens ($17{\beta}$-testosterone, $17{\alpha}$-testosterone), and gestagens (progesterone) and three synthetic hormones such as DES, zeranol, and taleranol. These hormones were analyzed by gas chromatographymass spectrometry. Newly developed multi-residue analysis method was applied for meat sample which were collected from market in the capital region and monitored the presence of residues of synthetic and natural steroid hormones. No residue of synthetic hormones were detected and endogenous level of progesterone was detected in cattle, pig and liver samples tested.

• Journal of Magnetics
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• v.15 no.3
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• pp.116-122
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• 2010

An accurate analytical equation for the total energy in the framework of the single domain model is used to study the thermal stability of nanostructured synthetic ferrimagnets. Elliptical cells are considered that have lateral dimensions of 160 nm (long axis)$\times$80 nm (short axis) and varying values of thickness asymmetry for the two magnetic layers. The direction of the applied magnetic field, which points to the $45^{\circ}$ direction, is in the opposite direction to the thicker layer magnetization. A significant difference is observed in the applied magnetic field dependencies of the equilibrium magnetic configuration and the magnetic energy barrier when using the simplifying assumption that the self-demagnetizing field is identical in magnitude to the dipole field. At a small thickness asymmetry of 0.2 nm, for example, the magnetic energy barrier is reduced from 68 kT (T=300 K) to 6 kT at the remanent state and a progressive switching behavior changes into a critical behavior, as the simplifying assumption is used. The present results clearly demonstrate the need for an accurate analytical equation for the total energy in predicting the thermal stability of nanostructured synthetic ferrimagnets.

• Analytical Science and Technology
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• v.15 no.4
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• pp.1039-1050
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• 2002

• Analytical Science and Technology
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• v.29 no.4
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• pp.162-169
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• 2016

The purpose of this study was to compare the relative bioavailability of synthetic Vitamin C and Nutra-C^® (calcium ascorbate) using a randomized parallel pharmacokinetics study design. Under fasting conditions, 20 healthy volunteers were randomly allocated to receive a single oral dose (500 mg of ascorbic acid) of either synthetic Vitamin C or Nutra-C^®. Fasting blood was collected pre-dose and 1, 2, 3, 4, 7 and 10 hr post-dose. The ascorbic acid content of human serum was determined using HPLC with ultraviolet detection. The fasting serum ascorbic acid concentrations of synthetic Vitamin C and Nutra-C^® were 6.734 ± 2.09 ng/mL (n = 10) and 7.542 ± 2.96 ng/mL (n = 10), respectively. The bioavailability of Nutra-C^® was significantly greater (128 %, p < 0.05) than that of the synthetic Vitamin C.

• MALSORI
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• no.64
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• pp.1-14
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• 2007

The purpose of this study was to examine the acoustic perception different by formants change for profoundly hearing impaired children with cochlear implants. The subjects were 10 children after 15 months of experience with the implant and mean of their chronological age was 8.4 years and Standard deviation was 2.9 years. The ability of auditory perception was assessed using acoustic-synthetic vowels. The acoustic-synthetic vowel was combined with F1, F2, and F3 into a vowel and produced 42 synthetic sound, using Speech GUI(Graphic User Interface) program. The data was deal with clustering analysis and on-line analytical processing for perception ability of acoustic synthetic vowel. The results showed that auditory perception scores of acoustic-synthetic vowels for cochlear implanted children were increased in F2 synthetic vowels compaire to those of F1. And it was found that they perceived the differences of vowels in terms of distance rates between F1 and F2 in specific vowel.

• Analytical Science and Technology
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• v.8 no.4
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• pp.465-468
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• 1995

Matrix assisted laser desorption ionization in mass spectrometry is a fast and accurate method to determine the molecular weight of natural and synthetic polymers. Unknown peptides such as elastase inhibitor and $\small{D}$-hydantoinase were analyzed using sinapinic acid as matrix and their molecular weights were compared with the results from protein sequencer and gel filtration chomatography, respectively. Synthetic polymers such as polyethyleneglycol, polypropyleneglycol, polydimethylsiloxane, and polystyrene were analyzed using matrices such as 2,5-dihydroxybenzoic acid, 4-hdroxyazobenzenecarboxylic acid, and 2-nitrophenyl octyl ether. Average molecular weights of polystyrene were compared with molecular weights by gel permeation chromatography.

• Analytical Science and Technology
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• v.34 no.4
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• pp.160-171
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• 2021

Synthetic azo dyes are used extensively in herbal medicines to render the medicines more visually attractive to consumers. This study developed and validated a rapid high-performance liquid chromatography (HPLC) method to determine whether synthetic colorants such as Tartrazine, Auramine O, Metanil yellow, Sunset yellow, and Orange II are used extensively in Typha orientalis. To increase the recovery of the synthetic dyes, this method employed containing 50 mM ammonium acetate in 70 % methanol at first extraction and 100 mM HCl in 70 % methanol at second extraction. Five synthetic pigments in Typha orientalis were separated by gradient elution with a mobile phase consisting of acetonitrile and 50 mM ammonium acetate in distilled water at ultra-violet (UV) detection 428 nm or 500 nm. Additionally, this study established the liquid chromatography tandem mass spectrometry (LC-MS/MS) method to confirm positive samples suspected by HPLC results. The HPLC-UV method had good linearity, indicating r²> 0.999. The recoveries of the samples spiked with three different concentration ranged from 73.8~91.5 %, and relative standard deviation values indicated 0.2~5.2 %. The established LC-MS/MS could successfully identify the synthetic pigments in herbal medicine samples. The study demonstrates that Typha orientalis adulterated by yellowish synthetic dyes can be successfully distinguished when using the HPLC-UV method.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.16 no.2
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• pp.91-100
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• 2006

The purpose of this study was to validate alternative method by using non-carcinogenic, and less toxic solvents than NIOSH analytical method 5524 for measuring the airborne MWFs in workplaces. In laboratory tests, the ETM solvents(mixture of same volume for ethyl ether, toluene, and ethanol) were selected. The alternative method of analyzing MWFs, referred to as the ETM solvent extraction method, showed 0.04 mg/sample as LOD, and 0.15 mg/sample as LOQ. The analytical precision (pooled CV, coefficient of variation) of the ETM solvent extraction method for analyzing the straight, soluble, semisynthetic, and synthetic metalworking fluid was 1.5%, 2.0%, 2.6%, 1.6%, respectively, which was similar to the precision (2.6%) of NIOSH analytical method (NIOSH 0500) for total dust. The analytical accuracy by recovery test, spiked mass calculated as extractable mass, was almost 100%. As the result of storage stability test, metalworking fluid samples should be stored in refrigerated condition, and be analyzed in two weeks after sampling. The 95% confidence limit of the estimated total standard error for the ETM solvent extraction method for analyzing the straight, soluble, semisynthetic, and synthetic metalworking fluid was ${\pm}12.6%$, ${\pm}12.5%$, ${\pm}14.0%$, and ${\pm}13.6%$, respectively, which satisfied the OSHA sampling and analytical criteria.

• Structural Engineering and Mechanics
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• v.23 no.4
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• pp.409-430
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• 2006

The aim of this study is to investigate the reliability of strong motion records processed by causal and acausal Butterworth filters in comparison to the results obtained from a synthetic accelerogram. For this purpose, the fault parallel component of the Bolu record of the Duzce earthquake is modeled with a sum of exponentially damped sinusoidal components. Noise-free velocities and displacements are then obtained by analytically integrating the synthetic acceleration model. The analytical velocity and displacement signals are used as a standard with which to judge the validity of the signals obtained by filtering with causal and acausal filters and numerically integrating the acceleration model. The results show that the acausal filters are clearly preferable to the causal filters due to the fact that the response spectra obtained from the acausal filters match the spectra obtained from the simulated accelerogram better than that obtained by causal filters. The response spectra are independent from the order of the filters and from the method of integration (whether analytical integration after a spline fit to the synthetic accelerogram or the trapezoidal rule). The response spectra are sensitive to the chosen corner frequency of both the causal and the acausal filters and also to the inclusion of the pads. Accurate prediction of the static residual displacement (SRD) is very important for structures traversing faults in the near-fault regions. The greatest adverse effect of the high pass filters is their removal of the SRD. However, the noise-free displacements obtained by double integrating the synthetic accelerogram analytically preserve the SRD. It is thus apparent that conventional high pass filters should not be used for processing near-fault strong-motion records although they can be reliably used for far-fault records if applied acausally. The ground motion parameters such as ARIAS intensity, HUSID plots, Housner spectral intensity and the duration of strong-motion are found to be insensitive to the causality of filters.