• Journal of Electrical Engineering and Technology
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• v.13 no.2
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• pp.981-988
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• 2018

In order to acquire an accurate TOF, this paper proposes a method that produces TOF by using a mathematical model for the envelope of the received signal obtained from a system dynamic model of ultrasonic transducer. The proposed method estimates the arrival time of the received signal retrospectively by comparing its wave form obtained after triggering point with its mathematical envelope model. Experimental result shows that the error due to variation of triggering point can be dramatically decreased by implementing the proposed method.

• Bulletin of the Korean Chemical Society
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• v.28 no.12
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• pp.2359-2362
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• 2007

MALDI-TOF-MS technique was applied to obtain structural and compositional information of synthetic polyamides, Nylon6 and Nylon66. Mass spectra of both the original and the hydrolyzed polyamide samples were analyzed using the self calibration method as well as the internal calibration method with the standard materials of known masses. The MALDI-TOF mass spectra of Nylon6 samples showed the presence of protonated, sodiated, and potassiated ions that were assigned to cyclic and NH2/COOH terminated linear oligomers. From the MALDI-TOF mass spectra of Nylon66 samples, the potassiated linear oligomers with three different end groups are identified as well as the cyclic oligomers, i.e., NH2/COOH terminated oligomers, NH2/NH2 terminated oligomers, and COOH/COOH terminated oligomers. Full characterization of the molecular species and end groups present in the polyamide samples has been achieved, and also the changes in mass spectral patterns after the hydrolysis of the samples are presented.

• KIPS Transactions on Computer and Communication Systems
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• v.4 no.11
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• pp.361-368
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• 2015

In AAGFCS the effective range is regarded as a range for the bullet's speed exceeding the speed of sound to damage the stationary target. Hence the real engagement range might be extended over the effective range for the approaching target since bullet's relative speed to the target increases depending on the approaching speed. However previous TOF equations have good computation accuracy within the effective range only, and they can not be used above that range due to their bad accuracy. We propose an accurate TOF computation method which can be used both within and above the effective range in real time. Some simulation results are shown to demonstrate usefulness of our algorithm for the 30mm projectile.

• Analytical Science and Technology
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• v.18 no.6
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• pp.483-490
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• 2005

Mass resolution of the time of flight aerosol mass spectrometer for an aerosol component analysis depends on the initial direction and the initial energy of the ions. We have found that the shape of the optimum post focusing electric field is not linear. The maximum electric potential should be applied to the ions whose initial direction is 90 degree. To check on the post focusing effects, we have installed a laser ablation mass spectrometer. By using this LA-MS, we have found that the average energy distribution of the laser ablated ions is 8 eV. To establish the optimum mass resolution, a time delay and a high voltage are needed, and the results of the study show that 1500 nsec, and 3.7 kV are the optimum parameters for our system respectively. The isotope mass signals of copper show a good resolution.

• Korean Journal of Clinical Laboratory Science
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• v.52 no.3
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• pp.221-228
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• 2020

Ochrobactrum anthropi is a non-fermentative oxidative gram-negative bacillus that produces oxidase. Distinguishing a mixed culture with non-fermenting bacteria having a similar appearance and oxidase-positive is difficult, and there is a limit to accurate identification with a biochemical identification system. This paper proposes that the Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry Platform (MALDI-TOF) method is useful for classifying bacteria that are difficult to identify using biochemical testing methods. As a result of analyzing five cases of O. anthropi examined using MicroScan, it took 6.5 days to the final report, which was 3.5 days more than the 3.0 days of E. coli. The pus sample in patient 5 was a mixed infection with Achromobacter xylosoxidans, and it took 11.3 days because of multiple subculture and retests. Four patients were over 60 years old with an underlying disease, and the possibility of opportunistic and nosocomial infections could not be excluded. Among them, samples collected after 92 days of hospitalization were resistant to imipenem and meropenem. Therefore, an examination using the MALDI-TOF method will be useful for the rapid and adequate treatment of patients with difficult identification, such as O. anthropi.

• Journal of Microbiology and Biotechnology
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• v.27 no.9
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• pp.1593-1601
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• 2017

Vibrio species are generally recognized as pathogens predominant in seafood along coastal areas. The food industry has sought to develop efficient microbial detection methods. Owing to the limits of conventional methods, this study aimed to establish a rapid identification method for Vibrio isolated from Korea, based on matrix-assisted laser-desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). Four different preparation procedures were compared to determine the appropriate means to pretreat Vibrio species, using 17 isolates and five reference strains. Extended direct transfer and full formic acid extraction methods using bacterial colonies on agar plates revealed very low identification rates. Formic acid and trifluoroacetic acid (TFA) extractions using bacterial broth cultures were also performed. All Vibrio isolates and reference strains prepared by TFA extraction were successfully identified to the species level (17/22, 77.3%) and to the genus level (5/22, 22.7%). Thus, TFA extraction was considered the most appropriate method to pretreat Vibrio species for MALDI-TOF MS. The remaining 33 isolates and two reference strains were prepared by TFA extraction and analyzed by MALDI-TOF MS. Overall, 50 isolates were identified to the species level (40/50, 80%) and to the genus level (10/50, 20%). All isolates were identified as 43 V. alginolyticus, six V. parahaemolyticus, and one V. vulnificus species. V. alginolyticus and V. parahaemolyticus were isolated from fish offal (87.5% and 12.5%, respectively), seawater (91.3%, 8.7%), and shellfish (62.5%, 37.5%), whereas V. alginolyticus and V. vulnificus were isolated from sediment (90.9% and 9.1%, respectively). This study established a reliable system of MALDI-TOF MS preparation and analysis for Vibrio identification.

• Journal of the Korean Society of Radiology
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• v.4 no.4
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• pp.29-32
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• 2010

The neutron capture cross section of $^{197}Au$ has been measured relative to the $^{10}B(n,{\gamma})$ standard cross section by the neutron time-of-flight(TOF) method using a 46-MeV electron linear accelerator(linac) at the Research Reactor Institute, Kyoto University(KURRI). In order to experimentally prove the result obtained, the supplementary cross section measurement has been made from 0.1 eV to 10 keV using the Kyoto University Lead slowing-down spectrometer (KULS) coupling to the linac. The relative measurement by the TOF method has been normalized to the reference value(24.5 b) at 1 eV. The evaluated capture cross sections in JENDL/D-99 Dosimetry have been compared with the current measurements by the KULS experiments.

• Journal of the Korean Society of Radiology
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• v.7 no.3
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• pp.245-249
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• 2013

Neutron sources from photonuclear reaction with 46-MeV electron linear accelerator at Research Reactor Institute, Kyoto University used for resonance energy measurement of natural tantalum. BGO($Bi_4Ge_3O_{12}$) scintillation detectors used for measurement of the prompt gamma ray from the natural tantalum sample. The BGO spectrometer was composed geometrically as total energy absorption detector. The electric signal from the spectrometer was analyzed for TOF(Time-of-Flight) spectrum which is used identification of neutron capture resonance energy. In this study, the neutron energy region is from 1 to 200 eV, because of strong X-ray effect produced photonuclear reaction in Ta target, the measurement was performed to below 1 keV energy region. The resonance energy was compared with the evaluated values(ENDF/B-VI, Mughabghab). All of the resonances from 4.28 ~ 200 eV were seen in the present measurement except 144.3 eV resonance.

• Journal of Broadcast Engineering
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• v.19 no.4
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• pp.533-546
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• 2014

This paper presents a method for a hybrid (color and depth) camera system construction using a photogrammetric technology. A TOF depth camera is efficient since it measures range information of objects in real-time. However, there are some problems of the TOF depth camera such as low resolution and noise due to surface conditions. Therefore, it is essential to not only correct depth noise and distortion but also construct the hybrid camera system providing a high resolution texture map for generating a 3D model using the depth camera. We estimated geometry of the hybrid camera using a traditional relative orientation algorithm and performed texture mapping using backward mapping based on a condition of collinearity. Other algorithm was compared to evaluate performance about the accuracy of a model and texture mapping. The result showed that the proposed method produced the higher model accuracy.

• Nuclear Engineering and Technology
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• v.54 no.7
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• pp.2592-2598
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• 2022

Research groups in the field of PET instrumentation are studying time-of-flight(TOF) technology to improve the signal-to-noise ratio of PET images. Scintillation light transport and collection plays an important role in improving the coincidence resolving time(CRT) of PET detector based on a pixelated crystal array. Four crystal arrays were designed by the different optical reflection configuration such as external reflectors and surface treatment on the CRT and compared with the light output, energy resolution and CRT. The design proposed in the study was composed of 8 × 8 LYSO crystal array consisted of 3 × 3 × 15 mm³ pixels. The entrance side was roughened while the other five surfaces were polished. Four sides of all crystal pixels were wrapped with ESR-film, and the entrance surface was covered by Teflon-tape. The design provided an excellent timing resolution of 210 ps and improved the CRT by 16% compared to the conventional method using a polishing treatment and ESR-film. This study provided a method for improving the light output and CRT of a pixelated scintillation crystal-based brain TOF PET detector. The proposed configuration might be an attractive detector design for TOF brain PET requiring fast timing performance with high cost-effectiveness.