• Journal of Biomedical Engineering Research
• /
• v.18 no.4
• /
• pp.421-428
• /
• 1997

Magnetic field sensors made from superconducting quantum interference device (SQUID) are the most sensitive low-frequency sensors available, enabling measurements of extremely weak magnetic fields from the brain. Neuromagnetic measurements allow superior spatial resolution, compared with the present electric measurements, and superior temporal resolution, compared with the fMRl and PET, providing useful informations for the functional diagnoses of the brain. We developed a 4-channel SQUID system for neuromagnetic applications. The main features of the system are its simple readout electronics and compact pickup coil structure. A magnetically shielded room has been constructed for the reduction of environmental magnetic noises. The developed SQUID system has noise level lower than the magnetic noise from the brain. Magnetic field signals of the spontaneous r-rhythm activity and auditory evoked magnetic fields have been measured.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.11 no.6
• /
• pp.553-560
• /
• 2016

There propagate use management paradigm in developed countries is changing as Command & Control $\Rightarrow$ Market Based $\Rightarrow$ Open Access $\Rightarrow$ Manage By Technology & Technical Analysis, that the policy response to environmental changes, such as a variety of new technologies. The emergence of service, the proliferation of propagation users It is to activate the market. However, the basic principles of radio management such that the change of paradigm be used to spread in a range that does not affect the interference, such as the horn is to be observed. Around the world in order to prevent the propagation and utilization Horn interference enacted regulations for managing the radio station, and also discipline.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.18 no.11
• /
• pp.2759-2764
• /
• 2014

Smoke detector is commonly used to reduce fire detection time. However, technical problems regarding its inaccuracy of laser beam-receiving point on the surface of the sensor associated with incoming interference are identified when the laser transmitter and receiver are installed at a distance of about 100m. In this paper, we propose the auto focus alignment algorithm with high precision to adjust tilting angle of lasers caused by environmental interference so that solve existing issues using multi-level worm gear set.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2010.03a
• /
• pp.229-239
• /
• 2010

Performing a series of in-situ thermal response tests, the effective thermal conductivity of six vertical closed-loop ground heat exchangers was experimentally evaluated and compared each other, which were constructed in a test bed in Wonju. To compare thermal efficiency of the ground heat exchangers in field, the six boreholes were constructed with different construction conditions: grouting materials (cement vs. bentonite), different additives (silica sand vs. graphite) and the shape of pipe-sections (general U-loop type vs. 3 pipe-type). From the test results, it can be concluded that cement grouting has a higher effective thermal conductivity than that of bentonite grouting, and the efficiency of graphite better performs over silica sand as a thermally-enhancing addictive. In addition, a new 3 pipe-type heat exchanger provides less thermal interference between the inlet and outlet pipe than the conventional U-loop type heat exchanger, which results in superior thermal performance.

• Membrane and Water Treatment
• /
• v.6 no.3
• /
• pp.189-203
• /
• 2015

Membrane biofouling impedes wide application of membrane bioreactor (MBR) for wastewater treatment. Recently, quorum sensing (QS) mechanisms are accounted for one of major mechanisms in biofouling of MBRs. In this study, vanillin was applied to investigate reduction of biofouling in MBRs. MBR sludge was analyzed to contain QS signal molecules by cross-feeding biosensor assay and HPLC. In addition, the inhibitory activity of vanillin against bacterial quorum sensing was verified using an indicator strain CV026. The vanillin doses greater than 125 mg/L to 100 mL of MBR sludge showed 25% reduction of biofilm formed on the membrane surfaces. Two MBRs, i.e., a typical MBR as a control and an MBR with vanillin, were operated. The TMP increases of the control MBR were more rapid compared to those of the MBR with the vanillin dose of 250 mg/L. The treatment efficiencies of the two MBRs on organic removal and MLSS were maintained relatively constant. Extracellular polymeric substance concentrations measured at the end of the MBR operation were 173 mg/g biocake for the control MBR and 119 mg/g biocake for the MBR with vanillin. Vanillin shows great potential as an anti-biofouling agent for MBRs without any interference on microbial activity for wastewater treatment.

• Analytical Science and Technology
• /
• v.32 no.3
• /
• pp.88-95
• /
• 2019

This study was conducted to establish the analytical method for the determination of cyanide in blood, urine, lung and skin tissues in rats. In order to detect or quantify the sodium cyanide in above biological matrixes, it was derivatized to Pentafluorobenzyl cyanide (PFB-CN) using pentafluorobenzyl bromide (PFB-Br) and then reaction substance was analyzed using gas chromatography mass spectrometer (GC/MS)-SIM (selected ion monitoring) mode. The analytical method for cyanide determination was validated with respect to parameters such as selectivity, system suitability, linearity, accuracy and precision. No interference peak was observed for the determination of cyanide in blank samples, zero samples and lower limit of quantification (LLOQ) samples. The lowest limit detection (LOD) for cyanide was $10{\mu}M$. The linear dynamic range was from 10 to $200{\mu}M$ for cyanide with correlation coefficients higher than 0.99. For quality control samples at four different concentrations including LLOQ that were analyzed in quintuplicate, on six separate occasions, the accuracy and precision range from -14.1 % to 14.5% and 2.7 % to 18.3 %, respectively. The GC/MS-based method of analysis established in this study could be applied to the toxicokinetic study of cyanide on biological matrix substrates such as blood, urine, lung and skin tissues.

• Journal of Positioning, Navigation, and Timing
• /
• v.11 no.1
• /
• pp.23-28
• /
• 2022

The eLoran system is a high-power terrestrial navigation system that is recognized as the most appropriate alternative to complement the GNSS's vulnerability to radio frequency interference. Accordingly, Korea has conducted eLoran technology development projects since 2016. The eLoran system developed in Korea provides 20 m positioning accuracy to maritime user in Incheon and Pyeongtaek harbor. To accurately calculate the position with the eLoran signal, it is necessary to apply a compensation method that mitigates the propagation delay. In this paper, we develop the compensation method to mitigate the eLoran signal propagation delay and evaluate the positioning performance in Incheon harbor. The propagation delay due to the terrain characteristics is pre-surveyed and stored in the user receiver. Real-time fluctuations in propagation delay compared to the pre-stored data are mitigated by the temporal correction generated at a nearby differential Loran station. Finally, two performance evaluation tests were performed to verify the positioning accuracy of the Korean eLoran system. The first test took place in December 2020 and the second in April 2021. As a result, the Korean eLoran service has been confirmed to provide 20 m location accuracy without GPS.

• Journal of the Korean Society of Environmental Restoration Technology
• /
• v.16 no.2
• /
• pp.63-74
• /
• 2013

This study suggests that some of the negative arguments related to naturalized plants raised in academic discussions are unreasonable through an analysis of trends in the academia's research on naturalized plants in South Korea. A total of 117 academic papers related to "naturalized plants" on the Korean Studies Information Service System (KISS) website were re-classified by space, the number of vascular plant species, the number of naturalized plant species, naturalization index (NI), and urbanization index (UI). Correlation between human interference and naturalized plant distribution, and between sizes of conservation areas and naturalized plant distribution were analyzed. According to the results, while there was a tendency between urban population and UI ($r^2$ = 0.70, p = .000), the number of visitors in national parks had no relation to either the NI or the UI (r = 0.028 and r = 0.013, respectively). Likewise, there was no correlation between national parks or conservation areas and naturalized plant distribution (r = 0.014, r = 0.17, respectively). The average NI and the UI of forest areas were approximately twice as low as those of national parks. In estimated regression equation, when one hypothesizes that the entire 4,952 taxa of plants growing in South Korea, the number of naturalized plants, combining paleo-naturalized plants and neo-naturalized plants, amounted to 2,398 taxa, 48.43%. In the academia, Korean Endemic Plants are less than one quarter of 4,952 taxa. Such results signify that, contrary to discussions in the academia, it is meaningless to distinguish between naturalized plants and native plants. In certain aspects, academic discussions on naturalized plants in Korea have proceeded in a manner similar to cultural exclusion by mono-culturalism in a multi-cultural environment.

• Journal of Environmental Health Sciences
• /
• v.35 no.2
• /
• pp.130-142
• /
• 2009

This study compared FTIR with XRD method for the analysis of quartz by % recovery, coefficient of variation (CV) and influence of the interference. the results were as the following. 1. In FTIR method, the coefficient of determination ($r^2$) was 0.9998 in a calibration curve of $695\;cm^{-1}$, and the limit of detection was $4.9{\mu}g/sample$. 2. The highest recovery was $799\;cm^{-1}$ (98.2%). 3. The CVpooled of the FTIR method was approximately 10% in three wave numbers. 4. The analysis of qualitative and quantitative for quartz is difficult with mixed cristobalite and iron oxide. 5. In XRD method with rotating sample holder and LynxEye detector, the coefficient of determination was 0.9996 in a calibration curve, and the limit of detection was $5.9{\mu}g/sample$. 6. The recovery and CV pooled were 104.3%, and 11 %, respectively. 7. In muffle furnace ashing, the quartz weight decreased to 34% when the maximum weight of the iron oxide was more than eight times. In conclusion, the accuracy (% recovery) and precision (CV) of FTIR and XRD method for analyzing $\alpha$-quartz were similar. FTIR method was a disadvantage for sample matrix because it indicates possibility of interference. However, XRD method distinguished specific crystalline forms of silica, and the majority of silicate minerals. In addition, XRD method recommend filter dissolution to pretreatment method.

• Journal of the Korean Society of Environmental Restoration Technology
• /
• v.21 no.1
• /
• pp.95-102
• /
• 2018

Only the habitat characteristics and breeding status of Paridae have been studied, in addition to the lack of research on Parus varius varius, there is no study on the home-range in the post fledging period. This study was analyzed the home-range size of Parus varius varius in the post fledging period. The survey was conducted in the site located in Dankook Univ. Cheonan Campus(Middle Chungcheong Province). We captured five newborn Parus varius varius using artificial nest was installed before. Radio-tracking was carried out for analysis of home-range, and MCP (Minimum Convex Polygon) was used for analysis. We analyzed 1 individual tracked 15 days (VT5) and 4 individuals which missing radio-tracking transmitter within 3 days (VT1~VT4). Home-range of VT5 gradually increased to 1,38ha, 1.42ha, 2.14ha in the order of early, middle, late period. On the other hand, moving distance was decreased to 174.558m 125.129m, 120.180m. Home-range of V1~VT4 was estimated as 0.81ha which was 75.3% share of home-range of VT5 in early period. As the result it was found that home-range is formed far apart from artificial nest that has been influenced by human being interference, thereafter gradually adapting to interference and spreading close to artificial nest. through this research, we can construct basic ecological data for protecting habitat of Parus varius varius and increasing life rate. As first radio-tracking study of Parus varius varius home-range in the post fledging period, it is expected to be useful for the future study of home-range.