• Korean Journal of Food Science and Technology
• /
• v.31 no.1
• /
• pp.74-82
• /
• 1999

Beef, pork and chicken meat that retailed in market were used as experimental samples. Some samples in raw state were packaged with PVDC as aerobic and vacuum condition. The other samples were cooked until internal temperature arrived at $70^{\circ}C$ using electric oven and then packaged immediately in the same way of raw samples. After these samples were irradiated by electron beam (0, 1, 2 kGy), irradiated samples were stored in refrigerator $(2{\sim}4^{\circ}C)$. Identification and quantification of cholesterol oxides were analysed at 0, 7, 14 days. The results were following. The results indicated that raw-vacuum packaged lower detected than that of other treatments. In raw-vacuum packaged, the amounts of $7{\beta}-hydroxycholesterol$ were detected slightly $(below\;0.5\;{\mu}ug/g)$ during storage, and 7-ketocholesterol were detected during every stored time and amounts of this detection were $8.02{\sim}101.30\;{\mu}g/g$. In cooked-aerobic packaged, total amounts of detection were higher than that of other treatments, total amounts of cholesterol oxides were detected about $51.18{\sim}155.90\;{\mu}g/g$ during storage. In all results, pork and chicken samples were similar to the results of beef samples. In all results, total amounts of cholesterol oxides increased significantly as irradiation dose and storage time increased (P<0.05).

• Journal of the Korean Vacuum Society
• /
• v.15 no.1
• /
• pp.97-102
• /
• 2006

Anodic alumina with self-organized and ordered nano hole arrays can be a good candidate of an irradiation mask to modify the properties of nano-scale region. In order to try using porous anodic alumina as a mask for ion-beam patterning, ion beam transmittance of anodic alumina was tested. 4 Um thick self-standing AAO templates anodized from Al bulk foil with two different aspect ratio, 200:1 and 100:1, were aligned about incident ion beam with finely controllable goniometer. At the best alignment, the transmittance of the AAO with aspect ratio of 200:1 and 100:1 were $10^{-8}\;and\;10^{-4}$, respectively. However transmittance of the thin film AAO with low aspect ratio, 5:1, were remarkably improved to 0.67. The ion beam transmittance of self-standing porous alumina with a thickness larger than $4{\mu}m$ is extremely low owing to high aspect ratio of nano hole and charging effect, even at a precise beam alignment to the direction of nano hole. $SiO_2$ nano dot array was formed by ion irradiation into thin film AAO on $SiO_2$ film. This was confirmed by scanning electron microscopy that the $SiO_2$ nano dot array is similar to AAO hole array.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.38 no.1
• /
• pp.121-124
• /
• 2009

This study was conducted to investigate the reason for the increase in the antioxidant activity of cooking drip from Enteroctopus dofleini by gamma and electron-beam irradiation. To define the effect of irradiation on the antioxidant activity of polyphenol in cooking drip, polyphenol excluded cooking drip extracts were prepared with polyclar$^{TM}$. But, the antioxidant activity of the cooking drip extracts without polyphenol was still increased by both irradiations. Instead, the effect on the proteins in the cooking drips prepared by ammonium sulfate precipitation showed great increase in antioxidative activity by irradiation. From these results, it was concluded that the increase in the antioxidative activity in cooking drips by the irradiation was caused by the structural modification of proteins in the cooking drips.

• Food Science and Preservation
• /
• v.16 no.2
• /
• pp.211-216
• /
• 2009

This study determined the photostimulated luminescence(PSL), thermoluminescence(TL), and electron spin resonance(ESR) properties of wheat and corn irradiated with 0-10 kGy of gamma-ray or electron-beam. PSL values of both irradiated grains, regardless of radiation source, were 241-429 photons/sec in nonirradiated samples(negative values, defined as ${\leq}700$ photons/60 sec) and 5,528-40,870 photons/60 sec in irradiated ones(positive values, defined as ${\geq}5,000$ photons/sec), thereby distinguishing irradiated from nonirradiated samples. The TL glow curves($TL_1$) peaked at around $300^{\circ}C$ in nonirradiated samples, but at about $180^{\circ}C$ in irradiated samples, at high intensities, regardless of radiation source. The TL ratios($TL_1/TL_2$) calculated to strengthen $TL_1$ data reliability were less than 0.03 for nonirradiated samples and over 0.20 for irradiated materials, in good agreement with threshold values for nonirradiated(${\leq}0.1$) and irradiated(${\geq}0.1$) samples. ESR analysis was not applicable in identification of irradiated wheat and corn. Electron-beam irradiation resulted in higher PSL and TL signals than did gamma-rays, at the same applied doses.

• Nuclear Engineering and Technology
• /
• v.46 no.2
• /
• pp.147-158
• /
• 2014

In order to investigate how the microstructure of fuel/matrix-interaction (FMI) layers change during irradiation, different U-7Mo dispersion fuel plates have been irradiated to high fission density and then characterized using scanning electron microscopy (SEM). Specifially, samples from irradiated U-7Mo dispersion fuel elements with pure Al, Al-2Si and AA4043 (~4.5 wt.%Si) matrices were SEM characterized using polished samples and samples that were prepared with a focused ion beam (FIB). Features not observable for the polished samples could be captured in SEM images taken of the FIB samples. For the Al matrix sample, a relatively large FMI layer develops, with enrichment of Xe at the FMI layer/Al matrix interface and evidence of debonding. Overall, a significant penetration of Si from the FMI layer into the U-7Mo fuel was observed for samples with Si in the Al matrix, which resulted in a change of the size (larger) and shape (round) of the fission gas bubbles. Additionally, solid fission product phases were observed to nucleate and grow within these bubbles. These changes in the localized regions of the microstructure of the U-7Mo may contribute to changes observed in the macroscopic swelling of fuel plates with Al-Si matrices.

• Korean journal of applied entomology
• /
• v.59 no.1
• /
• pp.25-35
• /
• 2020

The striped fruit fly, Zeugodacus scutellata, is endemic in Korea, but it has been regarded as one of the serious quarantine pests throughout the world. Sterile insect release technique (SIT) has been used to eradicate quarantine fruit flies. This study developed a technique to generate sterile males and applied SIT to control Z. scutellata. First of all, the reproductive systems of Z. scutellata adults were examined with fluorescent microscope. Polytrophic ovaries comprises of around 100 follicles with developing oocytes. Each follicle contains an oocyte with several nurse cells and are surrounded with follicular epithelium. Oocyte development began at 10 days after adult emergence (DAE) and formed chorionated oocytes after 20 DAE. On the other hand, male testes were well developed just after adult emergence. The vas deferens was filled with motile sperms. To generate sterile males, different doses (0~1,000 Gy) doses of electron beam were irradiated to 3~5 days old pupae of Z. scutellata. When male pupae were irradiated with electron beam at 200 Gy, they developed and mated with females without any significant difference compared to untreated males. Although the untreated females mated with the 200 Gy-irradiated males laid eggs, no eggs did not hatch. The 200 Gy-irradiated males were then applied to untreated male and female flies in a density ratio of 1:9 (untreated males : treated males). The laid eggs suffered significant infertility. These results suggest that electron beam-irradiated pupae at 200 Gy resulted in male sterility and the resulting males would be applied to SIT.

• Journal of the Korean Magnetics Society
• /
• v.12 no.5
• /
• pp.184-188
• /
• 2002

The Cu/Ni/Cu(002)/Si(100) films which have perpendicular magnetic anisotropy were deposited by e-beam evaporation methods. From the reflection high energy electron diffraction pattern, the films were confirmed to be grown epitaxially on silicon. After 2X lots ions/$\textrm{cm}^2$ C+ irradiation, magnetic easy-axis was changed from surface normal to in-plane as shown in the hysteresis loop of magneto-optical Kerr effects. It became manifest from analysis of X-ray reflectivity and grazing incident X-ray diffraction that even though interface between top Cu layer and Ni layer became rougher, the contrast of Cu and Ni's electron density became manifest after ion irradiation. In addition, the strain after deposition of the films was relaxed after ion irradiation. Strain relaxation related with change of magnetic properties and mechanism of intermixed layer's formation was explained by thermo-chemical driving force due to elastic and inelastic collision of ions.

• Progress in Medical Physics
• /
• v.15 no.1
• /
• pp.1-8
• /
• 2004

Patient dose verification is one of the most Important responsibilities of the physician in the treatment delivery of radiation therapy. For the task, it is necessary to use an accurate dosimeter that can verify the patient dose profile, and it is also necessary to determine the physical characteristics of beams used in intensity modulated radiation therapy (IMRT) The Beam Intensity Scanner (BInS) System is presented for the dosimetric verification of the two dimensional photon beam. The BInS has a scintillator, made of phosphor Terbium-doped Gadolinium Oxysulphide (Gd$_2$O$_2$S:Tb), to produce fluorescence from the irradiation of photon and electron beams. These fluoroscopic signals are collected and digitized by a digital video camera (DVC) and then processed by custom made software to express the relative dose profile in a 3 dimensional (3D) plot. As an application of the BInS, measurements related to IWRT are made and presented in this work. Using a static multileaf collimator (SMLC) technique, the intensity modulated beam (IMB) is delivered via a sequence of static portals made by controlled leaves. Thus, when static subfields are generated by a sequence of abutting portals, the penumbras and scattered photons of the delivered beams overlap in abutting field regions and this results in the creation of “hot spots”. Using the BInS, inter-step “hot spots” inherent in SMLC are measured and an empirical method to remove them is proposed. Another major MLC technique in IMRT, the dynamic multileaf collimator (DMLC) technique, has different characteristics from SMLC due to a different leaf operation mechanism during the irradiation of photon and electron beams. By using the BInS, the actual delivered doses by SMLC and DMLC techniques are measured and compared. Even if the planned dose to a target volume is equal in our experimental setting, the actual delivered dose by DMLC technique is measured to be larger by 14.8% than that by SMLC, and this is due to scattered photons and contaminant electrons at d$_{max}$.

• Food Science of Animal Resources
• /
• v.37 no.5
• /
• pp.698-707
• /
• 2017

This study was performed to investigate the impacts of irradiation sources on quality attributes of low-salt sausage during refrigerated storage. Control sausage was prepared with 1.5% sodium chloride (NaCl), whereas low-salt sausage was formulated with 0.75% NaCl (a 50% reduction; L-control). Sausage samples were vacuum-packaged, and low-sausages were irradiated with gamma-ray, electron-beam and X-ray at 5 kGy, respectively. The samples were stored at $4^{\circ}C$ for 28 d to determine changes in quality attributes. The pH of low-salt sausages was unaffected by irradiation at 5 kGy (p>0.05). Higher redness values were found at irradiated low-salt sausages compared to control (p<0.05). The hardness, gumminess and chewiness of control sausage were higher than those of low-salt sausages (p<0.05). However, there were no significant differences in the textural parameters between low-salt sausage treatments. The overall sensory acceptability score of irradiated/low-salt sausages were lower than L-control due to decreased scores for cooked meat flavor but increased radiolytic off-flavor (p<0.05). The initial 2-thiobarbituric acid-reactive substances (TBARS) values of irradiated/low-salt sausages were higher than control and L-control (p<0.05). However, the TBARS values of irradiated treatments were significantly lower than control at the end of storage. Irradiation could effectively inhibit the microorganism growth (total aerobic bacteria, coliforms, Enterobacteriaceae, and Pseudomonas spp.) in low-salt sausages (p<0.05). Therefore, our findings show that irradiation could be to improve microbial safety of low-salt sausages, and suggest that further studies should be necessary to reducing radiolytic off-flavor of irradiated/low-salt sausages.

• Korean Journal of Food Science and Technology
• /
• v.30 no.3
• /
• pp.509-516
• /
• 1998

Thermoluminescence measurements were applied to the detection of seasoned-powered foods such as shellfish extract powder, seasoned marine products, Ramen soup powder and sardine extract powder whether they are irradiated or not. Correlation coefficients $(R^2)$ between irradiation doses and corresponding TL responses were more than 0.5966 in all samples and 0.9500 in Ramen soup powder. TL threshold value was pre-established for the detection of unknown Ramen soup powders by verifying TL responses with a re-irradiation step. Threshold values were maximum 1.37 for the nonirradiated samples and minimum 6.06 for the 2.5 kGy-irradiated samples. The samples showing values between 1.37 and 6.06 were subjected to a re-irradiation step for their detection, which results were reconfirmed by enumerating the total bacterial load of the detected samples. Pre-established threshold values were successfully applicable to the detection of 167 coded unknown samples, both nonirradiated and irradiated with gamma or electron-beam energy. In the assessment of irradiated doses, three calibration curves were pre-established by plotting TL intensity versus applied doses, of which a quadratic equation was obtained for the potential estimation of irradiated doses with some variations from the real doses.