• Korean Journal of Fisheries and Aquatic Sciences
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• v.53 no.2
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• pp.174-180
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• 2020

The mouse bioassay has been used widely for the monitoring of paralytic shellfish toxins (PSTs) in many countries. However, this method shows low sensitivity and high limit of detection (LOD), as well as it cannot confirm toxic profiles. Recently, LC-MS/MS method was studied for the quantitative of PSTs, however, the method has any problems with unstable retention times by ionization suppression caused by high salt concentration in shellfish extracts. To establish an alternative method for PSTs analysis, we tried to original LC-MS/MS methods adding desalting operation using amorphous graphitized polymer carbon solid-phase extraction cartridges. The method validation was conducted to determine linearity, limit of detection, limit of quantification (LOQ), accuracy, and precision in quantifying PSTs. The correlation coefficients for all tested PSTs maintained over 0.999. The LODs and LOQs for all PSTs were about 0.19-1.05 ㎍/kg and 0.58-3.18 ㎍/kg, respectively. The accuracies for PSTs were 95.4-107.7% for saxitoxin group, 97.1-100.9% for gonyautoxin group, 99.0-100.8% for N-sulfocarbamoyl toxin group, and 96.8-104.6% for decarbamoyl toxin group. These results indicate that the modified LC-MS/MS method was appropriate for analyzing the PSTs in shellfish and tunicates.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.46 no.2
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• pp.154-159
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• 2013

The AOAC Mouse Bioassay method (MBA) has been widely used for routine monitoring of paralytic shellfish poisoning (PSP) for more than 50 years. However, this method has low sensitivity and experiences interference from other components in the extract. Also, ethical issues have been raised against the continued use of this live-mouse assay. To establish an alternative method for PSP analysis, we attempted to develop PSP analysis conditions using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The LC-MS/MS analysis of reference material showed very reasonable accuracy, and the analysis time was just 15 min. However, the recovery rate of toxin spike samples using the LC-MS/MS analysis was 59.4-91.0%. We also attempted to remove the matrix effect using shellfish extracts, but recoveries of C1 and C2 did not improve. A comparison between the results of MBA and LC-MS/MS analysis revealed good correlations, with values of 0.8878 and 0.9211 for oyster and mussel matrices, respectively.

• Journal of Conservation Science
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• v.33 no.5
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• pp.345-354
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• 2017

A mural was discovered in the Ssanggyesa temple located in Jindo island, during repair of the Daeungjeon Hall. A study was conducted to determine the binding medium used for preparing the mural. Pyrolysis/GC/MS and IR spectrometry were used to analyze a painting specimen. Direct approach and on-line methylation approach were attempted for the pyrolysis/GC/MS. In IR analysis, the spectra of the specimen were found to be different from those of Asian lacquer, yellow lacquer, animal glue, and acrylic emulsion resin. They were also not identical to the standard IR spectra of drying oils such as linseed oil. Pyrolysis/GC/MS results of the specimen were different from those of Asian lacquer, yellow lacquer, animal glue, and acrylic emulsion resin. In the mean time, palmitic acid, octadecanoic acid, nonanedioic acid, and octadecenoic acid, which are characteristic pyrolysis products of dried drying oil, were detected. In addition, the pyrolysis/GC/MS chromatograms of the specimen and dried drying oil were also very similar. Therefore, it was concluded that the painting was prepared using drying oil as a binding medium.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.48 no.3
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• pp.275-283
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• 2015

This study compared the sensory and nutritional characteristics of mottled skate Beringraja pulchra caught off Ulleung Island (U-MS), Korea, with those caught off Daecheong Island (D-MS). Based on their trichloroacetic acid-soluble nitrogen content, free amino acid content, and taste value, the taste of intermediate weight female U-MS was superior to that of both other U-MS and D-MS. The urea content of U-MS was higher in females than males and increased in the order heavy>intermediate>light individuals. There was, however, no difference in urea content between U-MS and D-MS. The taste and flavor characterization results suggest that the level of ammonia, which was converted from urea, influenced the quality of fermented U-DS. With the exception of the light U-DS, the other U-MS exhibited no difference in terms of hardness. The total amino acid content of U-MS was higher in females than males and increased in the order intermediate > heavy > light individuals. The total amino acid content of U-MS was also higher than that of D-MS. The major amino acids of all MSs were aspartic acid, glutamic acid, leucine, and lysine.

• Journal of the Korean Society of Safety
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• v.34 no.5
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• pp.31-36
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• 2019

This study made a testing device to evaluate the distribution board management system. Power was supplied to the testing device using a loading-back method and the voltage applied to it was 440 V at the same turn ratio. When the human body electric shock current is 30 mA, the breaking time is set to be less than 240 ms while 30~45 mA current is flowing. The test result shows that in the case of the R-phase it was measured to be 5.19 Hz (193 ms). And the S-phase and T-phase were perfectly cut off at 5.39 Hz (186 ms) and 5.71 Hz (175 ms), respectively. When the human body electric shock current is 60mA, the breaking time is set to be less than 120 ms while 45~75 mA current is flowing. The test result shows that the R-phase, S-phase, and T-phase were accurately cut off at 8.39 Hz (11 ms), 8.87Hz (113 ms) and 9.69 Hz (103 ms), respectively. When the human body electric shock current is 90 mA, the breaking time is set to be less than 48 ms while 75 mA current is flowing. The test result shows that the R-phase, S-phase, and T-phase were accurately cut off at 19.8 Hz (50.4 ms), 16.9 Hz (59.2 ms), and 17.9 Hz (56.0 ms), respectively. That is, the developed testing device satisfied all the requirements of the distribution board evaluation criteria, and it becomes available for the performance evaluation of the distribution board management system.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.39 no.1
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• pp.13-21
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• 2021

High-resolution satellites such as Kompsat-3 and CAS-500 include optical cameras of MS (Multispectral) and PAN (Panchromatic) CCD (Charge Coupled Device) sensors installed with certain offsets. The offsets between the CCD sensors produce geometric discrepancy between MS and PAN images because a ground target is imaged at slightly different times for MS and PAN sensors. For precise pan-sharpening process, we propose a co-registration process consisting the physical sensor modeling and image matching. The physical sensor model enables the initial co-registration and the image matching is carried out for further refinement. An experiment with Kompsat-3 images produced RMSE (Root Mean Square Error) 0.2pixels level of geometric discrepancy between MS and PAN images.

• Journal of Biomedical Engineering Research
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• v.42 no.5
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• pp.211-224
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• 2021

Purpose: The purpose of this study is to present a way to alleviate motion sickness(MS) by stimulating acupoint through PEMFs, and to assess the effectiveness of PEMFs against stimulation previously used to stimulate acupoint using biosignal evaluations and surveys. Materials and Methods: Thirteen healthy men participated in the experiment. MS was induced in the participants, and MS relief stimulation was applied for 30 minutes. There were 4 types of MS relief stimulation, and Sham, Reliefband, Transcutaneous electrical nerve stimulation(TENS), and Pulsed electromagnetic fields stimulation(PEMFs) were used. The biosignals were measured during 30 minutes of applying MS relief stimulation, and the symptoms of MS were evaluated through a questionnaire survey. The measured biosignals are Electrocardiogram(ECG), Electrodermal activity(EDA), Respiration, Skin temperature(SKT), and Electrogastrogram(EGG). A one-way ANOVA test was performed for the rate of change by stimulation for MS relief over time. Results: Participants who were stimulated had a sharp decrease in MS symptoms. Biosignals were analyzed to evaluate autonomic nervous system activity, and the parasympathetic nervous system could be activated through stimulation. Conclusion: TENS and PEMFs were more effective in relieving MS symptoms than Reliefband. It is believed that PEMFs will be effective in consideration of the comfort of participants to be applied to actual vehicles, and studies to further verify the effects of PEMFs on MS should be conducted.

• Journal of Korean Society of Environmental Engineers
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• v.31 no.9
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• pp.825-830
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• 2009

Pharmaceutical compounds enter the water environment through the diverse pathways. Because their concentration in the water environment was frequently detected in the level of ppt to ppb, the monitoring system should be optimized as much as possible for finding appropriate management policies and technical solutions. One Factor At a Time (OFAT) approach approximating the response with a single variable has been preferred for the optimization of LC-MS/MS operational conditions. However, it is common that variables in analytical instruments are interdependent. Therefore, the best condition could be found by using the statistical optimization method changing multiple variables at a time. In this research, response surface analysis (RSA) was applied to the LC-MS/MS analysis of emerging antibiotic compound, sulfamethoxazole, for the best sensitivity. In the screening test, fragmentation energy and collision voltage were selected as independent variables. They were changed simultaneously for the statistical optimization and a polynomial equation was fit to the data set. The correlation coefficient, $R^2$ valuerepresented 0.9947 and the error between the predicted and observed value showed only 3.41% at the random condition, fragmentation energy of 60 and collision voltage of 17 eV. Therefore, it was concluded that the model derived by RSA successfully predict the response. The optimal conditions identified by the model were fragmentation energy of 116.6 and collision voltage of 10.9 eV. This RSA can be extensively utilized for optimizing conditions of solid-phase extraction and liquid chromatography.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.1
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• pp.129-134
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• 2014

This paper presents a 10-bit 10-MS/s asynchronous successive approximation register (SAR) analog-to-digital converter (ADC) which consists of a digital-to-analog converter (DAC), a SAR logic, and a comparator. The designed asynchronous SAR ADC with a rail-to-rail input range uses a binary weighted DAC using metal-oxide-metal (MOM) capacitor to improve sampling rate. The proposed 10-bit 10-MS/s asynchronous SAR ADC is fabricated using a 0.18-${\mu}m$ CMOS process and its active area is $0.103mm^2$. The power consumption is 0.37 mW when the voltage of supply is 1.1 V. The measured SNDR are 54.19 dB and 51.59 dB at the analog input frequency of 101.12 kHz and 5.12 MHz, respectively.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.2
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• pp.414-422
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• 2013

This paper describes a 10-bit 10-MS/s asynchronous successive approximation register (SAR) analog-to-digital converter (ADC) using a split-capacitor-based differential digital-to-analog converter (DAC). SAR logic and comparator are asynchronously operated to increase the sampling frequency. The time-domain comparator with an offset calibration technique is used to achieve a high resolution. The proposed 10-bit 10-MS/s asynchronous SAR ADC with the area of $140{\times}420{\mu}m^2$ is fabricated using a 0.18-${\mu}m$ CMOS process. Its power consumption is 1.19 mW at 1.8 V supply. The measured SNDR is 49.95 dB for the analog input frequency of 101 kHz. The DNL and INL are +0.57/-0.67 and +1.73/-1.58, respectively.