• KSBB Journal
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• v.27 no.3
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• pp.195-198
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• 2012

This study was carried out to assess the effect of radiation on the changes of Hizikia fusiformis cooking juice ethanol extract and to compare the effect of gamma ray and electron beam. On the applying radiation, the dark color of cooking juice became changed with higher brightness and lower redness and yellowness. But, there was no difference between gamma ray radiation and electron beam radiation. 1,1-Diphenyl-2-picryl-hydrazyl radical scavenging activity and tyrosinase inhibitory activity of cooking juice were shown to be increased by radiation independent on the radiation source types. The reason for the increased biological activities was caused by higher content of total phenolic compounds. The results could be applied to investigate the effect of radiation source on the color and antioxidant activity of biomaterials, and it was thought that irradiation could be an promising method for enhancing the biological activity of biomaterials.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.20 no.3
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• pp.342-349
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• 2011

The purpose of this paper is to describe experimental results about the butt welding and bead on plate welding of the high power Continuous Wave (CW) Fiber laser for Ultra-low carbon Interstitial Free(IF) steel plate for gear part of car. After being welded of the gear parts by the fiber laser and electron beam Microstructures of melting zone had been mixed acicular, granular bainitic, quasi-polygonal and widmanstatten ferrite because of a radical thermal diffusion after welding, difference of critical volume and grain size. As a result of experiment, when gear parts were welded by the fiber laser and electron beam, the fiber laser welding has been stable properties without internal defects more than the electron beam welding. Therefore it has the very advantages of welding high quality and productivity more than conventional melting method. The optimal welding processing parameters for gear parts were as follows : the laser power and welding speed were 3kWatt, 30mm/sec respectively. At this time heat input was $21.2{\times}10^3J/cm^2$.

• Journal of Radiation Protection and Research
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• v.46 no.1
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• pp.8-13
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• 2021

Background: Salmonella enteritidis (SE) was the main cause of the pandemic of foodborne salmonellosis. The surface of eggs' shells can be contaminated with this bacterium; however, washing them with sodium hypochlorite solution not only reduces their flavor but also heavily impacts the environment. An alternative to this is surface sterilization using low-energy electron beam. It is known that irradiation with 1 kGy resulted in a significant 3.9 log reduction (reduction factor of 10,000) in detectable SE on the shell. FAO/IAEA/WHO indicates irradiation of any food commodity up to an overall average dose of 10 kGy presents no toxicological hazard. On the other hand, the Food and Drug Administration has deemed a dose of up to 3 kGy is allowable for eggs. However, the maximum dose permitted to be absorbed by an edible part (i.e., internal dose) is 0.1 Gy in Japan and 0.5 Gy in European Union. Materials and Methods: The electron beam (EB) depth dose distribution in the eggshell was calculated by the Monte Carlo method. The internal dose was also estimated by Monte Carlo simulation and experimentation. Results and Discussion: The EB depth dose distribution for the eggshells indicated that acceleration voltages between 80 and 200 kV were optimal for eggshell sterilization. It was also found that acceleration voltages between 80 and 150 kV were suitable for reducing the internal dose to ≤ 0.10 Gy. Conclusion: The optimum irradiative conditions for sterilizing only eggshells with an EB were between 80 and 150 kV.

• Proceedings of the Materials Research Society of Korea Conference
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• 2012.05a
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• pp.56.1-56.1
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• 2012

The microstructures and mechanical properties of Co-29Cr-6Mo alloy with C and N additions, produced by additive manufacturing using electron beam melting (EBM) method, were studied using X-ray diffraction, electron back scatter diffraction, transmission electron microscope, Vickers hardness tests, and tensile tests, focusing on the influences on the build direction and the various heat treatments after build. It is found that the microstructures for the as built specimens were changed from columnar to equiaxed grain structure with average grain size of approximately $10-20{\mu}m$ due to the heat treatment employing the reverse transformation from a lamellar (hcp + $Cr_2N$) phase to an fcc. Our results will contribute to the development of biomedical Ni-free Co-Cr-Mo-N-C alloys, produced by EBM method, with refined grain size and good mechanical properties, without requiring any hot workings.

• Progress in Medical Physics
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• v.5 no.1
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• pp.87-99
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• 1994

Purpose : The determination of electron beam output factor was investigated from individual applicator for various energy of ML-15MDX linear accelerator. The output factor of electron beam was extended from square to rectangular field in individual applicator size through with a least-square fit to a polynomial expression. Materials : In this experiments. the measurement of output was obtained from 2${\times}$cm$^2$ to 20${\times}$20cm$^2$ of field size in different applicator size for 4 to 15 MaV electron beam energy. The output factor was defined as the ratio of maximum dose output on the central axis of the field of individual applicator size to that of a given field size. Applicator factors were derived from comparing with the output dose of reference field size 10${\times}$10cm$^2$. The thickness of block was specially designed as 10mm in thickness of Lipowitz metal for field shaping in all electron energy. Two types of output curves are included as output factors versus side of square fields and that of variable side length for X and Y in one-dimensional to compare the expected values to that of experiments. Results : Expected output factors of rectangular which was derived from that of square fields in individual applicator size from 2${\times}$2cm$^2$ to 20${\times}$20cm$^2$ in different electron energy was very closed to that of experimental measurements within 2% uncertainty. However 1D method showed a 3% discrepancy in small rectangular field for low energy electron beam. Conclusion : Emperical non-linear polynomial regressions of square root and 1D method were performed to determin the output factor in various field size and electron energy. The expected output of electron beam of square root method for square field and 1D method for rectangular field were very closed to that of measurement in all selected electron beam energy.

• JSTS:Journal of Semiconductor Technology and Science
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• v.12 no.1
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• pp.34-40
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• 2012

We have developed a highly sensitive inspection technique based on an electron beam inspection for detecting the contact failure of a poly-Si plugged layer. It was difficult to distinguish the contact failure from normal landing plugs with high impedance. Normally, the thermal annealing method has been used to decrease the impedance of poly-Si plugs and this method increases the difference of charged characteristics and voltage contrast. However, the additional process made the loss of time and broke down the device characteristics. Here, the interval scanning method without thermal annealing was effectively applied to enhance the difference of surface voltage between well-contacted poly-Si plugs and incomplete contact plugs. It is extremely useful to detect the contact failures of non-annealed plug contacts with high impedance.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.11a
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• pp.311-312
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• 2005

By using 45$^{\circ}$ obliqued evaporation method with electron beam system, uniformly vertical liquid crystal (LC) alignment was achieved. And a high pretilt angles of about 2.5$^{\circ}$ were measured. Also, it was verified that there are no variations of pretilt angle as a function of $SiO_x$ thin film thickness 20nm and 50nm. A good LC alignment states were observed at annealing temperature of 250$^{\circ}C$. The high pretilt angle and the good thermal stability of LC alignment by 45$^{\circ}$ obliqued electron beam evaporation method on the $SiO_x$ thin film can be achieved.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.18 no.11
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• pp.1024-1027
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• 2005

By using $45^{\circ}$ obliqued evaporation method with electron beam system, uniformly vertical liquid crystal (LC) alignment was achieved. And a high pretilt angles of about $2.5^{\circ}$ were measured. Also, it was verified that there are no variations of pretilt angle as a function of $SiO_x$ thin film thickness 20 nm and 50 nm. A good LC alignment states were observed at annealing temperature of $250^{\circ}C$. Consequently, the high pretilt angle and the good thermal stability of LC alignment by $45^{\circ}$ obliqued electron beam evaporation method on the $SiO_x$ thin film can be achieved.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.05c
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• pp.11-14
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• 2002

Accurate sets of electron collision cross sections for atoms and molecules are necessary for quantitative understanding and modeling of plasma phenomena. So, in this study, we explains the concept of electron collision cross sections for gases, and the principle of determination of the electron collision cross sections for atoms and molecules by using the present electron swarm method.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.16 no.8
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• pp.719-731
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• 1991

This paper introduces a relatively simple computer simulation method for analyzing trajectory of electron beam in cylindrical electrode of the CRT, which outputs the cutoff voltag, beam current, spot size and plots out the trajectory, rom the input data on physical construction and applied voltages of electron gun. In order to improve computing speed in obtaining potential distibution, the authors have ivided the space into seveal setos and allocated different mesh sizes epending on the acuracy required to each sector and applied the finite difference method in calculation. The plot of trajectoy obtained from the simulation provided useful insight into the focusing mechanism of the CRT. The computed and measured result including beam curent. spot sizs and cutoff voltages for several model guns have ageed within eperimental error. The simulation program enables the designer to compare the effects of varied electrode shpe without the epense of building an actual gun and may be appli in esigning and implementing the electron gun assemply.