• 방사선산업학회지
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• 제6권1호
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• pp.17-21
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• 2012

The effects of gamma ray or electron beam irradiation on herbaceous medicinal plants were investigated in terms of the composition of volatile constituents using the aerial parts or leaves of Artemisia princeps Pamp. cv. Ganghwayakssuk and Artemisia argyi cvs. Namhaeyakssuk and Hwanghaessuk. The composition of volatile constituents in leaves was clearly distinguishable among the three Artemisia cultivars. However, the relative proportions of the major volatile constituents such as 1,8-cineole, ${\alpha}$-pinene, camphene, santolina triene, and artemesia triene, were similarly changed in two or three cultivars by gamma ray or electron beam irradiation. In particular, the proportion of 1,8-cineole was increased up to 1.29- to 1.71-fold in the three cultivars after irradiation with gamma ray. These results suggest that gamma ray or electron beam irradiation can be applied to modulate the composition of volatile constituents in the leaves of Artemisia plants.

• 방사선산업학회지
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• 제6권3호
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• pp.231-237
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• 2012

This paper introduces a gamma-ray measurement system for a transportable tomography which is applicable for an industrial process diagnosis. The gamma-ray measurement system consists of pulse mode operating 72 channel CsI detectors, main AMP-pulse shaper, single channel analyzer, counter and control PC. The CsI crystal is coupled with a PIN diode which is connected to an amplifier and pulse shaper. For a compact design, the amplifier and pulse shaping circuit are included in a single package. 36 sets of CsI detectors are connected to a multi-channel counter through single channel analyzers. A computer controls and collects data from two multi-channel counters. This configuration results in 72 channel counting system in total. The CT rotator and radiation measurement system are controlled by a PC with LabVIEW program. Tomographic data were measured for a phantom by the measurement system and transportable gamma-ray CT. From the experimental data image reconstructions were performed by ML-EM algorithm. The result showed that the CsI detector system can be a suitable component for transportable gamma-ray CT system.

• Nuclear Engineering and Technology
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• 제54권9호
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• pp.3398-3402
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• 2022

We fabricated a 15 m long position-sensitive plastic scintillation optical fiber (PSOF) detector consisting of a PSOF, two photomultiplier tubes, four fast amplifiers, and a digitizer. A single PSOF was used as a sensing part to estimate the gamma-ray source position, and ¹³⁷Cs, an uncollimated solid-disk-type radioactive isotope, was used as a gamma-ray emitter. To improve the sensitivity, accuracy, and measurement time of a PSOF detector compared to those of previous studies, the performance of the amplifier was optimized, and the digital signal processing (DSP) was newly designed in this study. Moreover, we could measure very low dose rates of gamma-rays with high sensitivity and accuracy in a very short time using our proposed PSOF detector. The results of this study indicate that it is possible to accurately and quickly locate the position of a very low dose rate gamma-ray source in a wide range of contaminated areas using the proposed position-sensitive PSOF detector.

• 천문학논총
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• 제30권2호
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• pp.559-563
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• 2015

Monitor of All-sky X-ray Image (MAXI) is a Japanese X-ray all-sky surveyer mounted on the International Space Station (ISS). It has been scanning the whole sky since 2009 during every 92-minute ISS rotation. X-ray transients are quickly found by the real-time nova-search program. As a result, MAXI has issued 133 Astronomer's Telegrams and 44 Gamma-ray burst Coordinated Networks so far. MAXI has discovered six new black holes (BH) in 4.5 years. Long-term behaviors of the MAXI BHs can be classified into two types by their outbursts; a fast-rise exponential-decay type and a fast-rise flat-top one. The slit camera is suitable for accumulating data over a long time. MAXI issued a 37-month catalog containing 500 sources above a ~0.6 mCrab detection limit at 4-10 keV in the region ${\mid}{b}{\mid}$ > $10^{\circ}$. The SSC instrument utilizing an X-ray CCD has detected diffuse soft X-rays extending over a large solid angle, such as the Cygnus super bubble. MAXI/SSC has also detcted a Ne emission line from the rapid soft X-ray nova MAXI J0158-744. The overall shapes of outbursts in Be X-ray binaries (BeXRB) are precisely observed with MAXI/GSC. BeXRB have two kinds of outbursts, a normal outburst and a giant one. The peak dates of the subsequent giant outbursts of A0535+26 repeated with a different period than the orbital one. The Be stellar disk is considered to either have a precession motion or a distorted shape. The long-term behaviors of low-mass X-ray binaries (LMXB) containing weakly magnetized neutron stars are investigated. Transient LMXBs (Aql X-1 and 4U 1608-52) repeated outbursts every 200-1000 days, which is understood by the limit-cycle of hydrogen ionization states in the outer accretion disk. A third state (very dim state) in Aql X-1 and 4U 1608-52 was interpreted as the propeller effect in the unified picture of LMXB. Cir X-1 is a peculiar source in the sense that its long-term behavior is not like typical LMXBs. The luminosity sometimes decreases suddenly at periastron. It might be explained by the stripping of the outer accretion disk by a clumpy stellar wind. MAXI observed 64 large flares from 22 active stars (RS CVns, dMe stars, Argol types, young stellar objects) over 4 years. The total energies are $10^{34}-10^{36}$ erg $s^{-1}$. Since MAXI can measure the spectrum (temperature and emission measure), we can estimate the size of the plasma and the magnetic fields. The size sometimes exceeds the size of the star. The magnetic field is in the range of 10-100 gauss, which is a typical value for solar flares.

• 한국CDE학회논문집
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• 제16권4호
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• pp.285-291
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• 2011

A pose estimation process from medical images is calculating locations and orientations of objects obtained from Computed Tomography (CT) volume data utilizing X-ray images from two directions. In this process, digitally reconstructed radiograph (DRR) images of spatially transformed objects are generated and compared to X-ray images repeatedly until reasonable transformation matrices of the objects are found. The DRR generation and image comparison take majority of the total time for this pose estimation. In this paper, a fast DRR generation technique based on GPU parallel computing is introduced. A volume ray-casting algorithm is explained with brief vector operations and a parallelization technique of the algorithm using Compute Unified Device Architecture (CUDA) is discussed. This paper also presents the implementation results and time measurements comparing to those from pure-CPU implementation and open source toolkit.

• Journal of Astronomy and Space Sciences
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• 제37권3호
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• pp.165-170
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• 2020

Muons and neutrons are representative secondary particles that are generated by interactions between primary cosmic ray particles (mostly protons) and the nuclei of atmospheric gas compounds. Previous studies reported that muons experience seasonal variations because of the meteorological effects of temperature. The intensity of neutrons has a typical modulation with various periods and reasons, such as diurnal and solar variation or transient events. This paper reports that cosmic ray particles, which were observed by neutron monitors, have seasonal variations using the daily data at the Oulu neutron monitor. To eliminate the effects of solar activity across time, the daily data were normalized by two different transformations: transformations with respect to the grand mean and yearly mean. The data after transformation with respect to the yearly mean showed more statistical stability and clear seasonal variations. On the other hand, it is difficult to determine if the seasonal variation results from terrestrial effects, such as meteorological factors, or extraterrestrial effects, such as the position of the Earth in its orbit of revolution.

• 약학회지
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• 제40권4호
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• pp.382-386
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• 1996

The compound of the 6,7-dichloroquinoline-5,8-dione has two asymmetric chloro radicals at the position of the C6 and C7. When the compound reacts with ethyl acetoacetate in the presence of sodium ethoxide, it is considered that C6 and/or C7 position of the compound can be substitued. The exact substitued position of the product (I) could not be identified by the NMR analysis in our experiment. Therefore, we synthesized the 3-ethoxycarbonyl-2-methyl-1-N-propyl pyridino(2,3f)indole-4,9-dione by reaction of the product (I) with propylamine via intramolecular cyclization to identify the substitued position of the product (I) using the X-ray crystallographic structure analysis. The result demonstrates that the position of nucleophilic substitution of the product (I) is at the position of the C6.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.63.3-63
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• 2001

Inspection and shape measurement of three-dimensional objects are widely needed in industries for quality monitoring and control. In this paper, we propose a three dimensional volume reconstruction method, which is an iterative method and as uniform and simulated algebraic reconstruction technique (USART). In this method, two or more x-ray images projected from different views are needed, and also the geometry of the imaging system need to be a priori identified well. That is to say, the relative locations between the x-ray source, imaging plane and the object should be determined exactly by calibration. To achieve this, we propose a series of coordinate calibration methods of the x-ray imaging system using grid pattern images. Some experimental results of these calibrations is presented and discussed in detail ...

• Tribology and Lubricants
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• 제20권1호
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• pp.7-13
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• 2004

High strength steels are widely used as tribo-materials in the field. Previous study revealed that for mild steel, the states of strain on the worn surface measured by X-ray diffraction has a good relationship with the state of wear. The objective of this study is to identify the relationship between the state of strain on the worn surface and the state of wear in high strength steels. Sliding wear tests were carried out using several hardened steels. X-ray diffraction tests were conducted to analyze the state of strain on the worn surface during wear. The experimental results indicated that the state of strain on worn surface in the hardened steel shows the same tendency as in the mild steel. It is clear that change of half value width on the worn surface as a function of sliding speeds is broadly similar in shape to wear characteristics curve and its magnitude has a good relationship with the wear rate at two different wear modes in the hardened steel.

• 천문학회지
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• 제38권1호
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• pp.1-6
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• 2005

We searched for X-ray emission from the 665 galaxies inside and towards the nearby voids by analyzing the ROSAT All-Sky Survey (RASS) data as well as the ROSAT pointed observations (PSPC). As a result we have detected six X-ray emitting galaxies. Two (UGC 10205 and NGC 7509) are in the high density region in the local void, three (UGC 749, MCG +11-10-073, and Mrk 464) are towards the nearby voids, and UGC 32 is located in the low density region. We carried out a timing analysis for both Mrk 464 and UGC 32, and a spectral analysis for Mrk 464. The light curve of Mrk 464 shows the possibility of periodic X-ray flux variation and UGC 32 shows weak, but rapid variation.