• Journal of the Korean Ceramic Society
• /
• v.41 no.2
• /
• pp.102-105
• /
• 2004

ZnO-In$_2$O$_3$ films were fabricated on Corning 1737 glass substrate by an electron beam evaporation technique and their characteristics were investigated. The composition of ZnO-In$_2$O$_3$ films had a marked effect on the electrical properties of the films. The ZnO-In$_2$O$_3$ films showed superior transparent-conducting characteristics with increase of Zn content. The resistivity and carrier concentration of the film having Zn content of 45 at% are 4.45${\times}$10$^{-3}$ cm and 3.1${\times}$10$^{19}$ cm$^{-3}$ , respectively. Also, the transmittance was higher than 80% throughout the visible range. The average roughness of the film was 14.6 $\AA$ in terms of root mean square.

• Proceedings of the KIEE Conference
• /
• 1996.07c
• /
• pp.1559-1561
• /
• 1996

In this experiment, it is decided to irradiated with a low dose of electron beam. Such that being things, the specimen is produced by the different dose, for example, 0.5[Mrad], 1[Mrad], 2[Mrad] except for original specimen. From the result of the analysis for the physical properties using FT-IR spectrum, it is confirmed that carbonyl groups of irradiated specimen is increased more than that of non-irradiated specimen. And all of nitric compound are disappeared by irradiating with electron beam. From the result of the dielectric characteristics, the specimen irradiated with 2[Mrad] is excellent.

• Proceedings of the KIEE Conference
• /
• 1998.07e
• /
• pp.1767-1769
• /
• 1998

We have established a pulsed electron beam generation system with an energy of 200[keV], pulse repetition rate of 200[Hz], and several tens of [${\mu}s$] pulse width. The system is characterized by a cold cathode that is simpler than the hot cathode. Target object does not need to be scanned because of large aperture electron beam of 300[$cm^2$]. Electron source is secondary electrons that are generated when the ions from the glow discharge collide on the cathode surface. In this paper, the discharge current characteristics are investigated experimentally as a function of He gas pressure in order to obtain stable glow discharge. And computer simulations are carried out as a preliminary study for the development of low energy large aperture electron beam generator. The variation of electon beam current is investigated as a function of rising time of high voltage when 20[kV] potential is applied in 20[mTorr] pressure.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2008.06a
• /
• pp.377-378
• /
• 2008

Space charge formation in various glass materials under electron beam irradiation was investigated. Charging of spacecraft occurs in plasma and radiation environment. Especially, we focused on an accident caused by internal charging in a glass material that was used as the cover plate of solar panel array, and tried to measure the charge distribution in glass materials under electron beam irradiation by using a PEA (Pulsed Electro-Acoustic method) system. In the case of a quartz glass (pure $SiO_2$), no charge accumulation was observed either during or after the electron beam irradiation. On the contrary, positive charge accumulation was observed in glass samples containing metal-oxide components. It is found that the polarity of the observed charges depends on the contents of the impurities. To identify which impurity dominates the polarity of the accumulated charge, we measured charge distributions in several glass materials containing various metal-oxide components and calculated the trap energy depths from the charge decay characteristics of all glass samples. Furthermore, the dependence of the polarity of accumulated charges on the component of glass materials is discussed by using the models of energy bands.

• Journal of Applied Biological Chemistry
• /
• v.55 no.4
• /
• pp.267-272
• /
• 2012

We investigated that electron beam irradiation is the effective method to control the sprouting of sweetpotato roots without changing of food quality characteristics. In 12 and $25^{\circ}C$ storage after electron beam irradiation, all control samples were sprouted from 6 and 4 weeks after storage, respectively. The sprouting rate of control increased with time and the rate reached to 11.2-12.4 and 70.5-74.2% at 8 weeks after 12 and $25^{\circ}C$ storage. Also, the sprouting of middle and below positioning sweetpotato roots at 12 and $25^{\circ}C$ storage after irradiation reached to 8.6-11.3 and 42.7-48.7% after a storage period of 8 weeks, respectively. However, the sprouting of all sweetpotato roots stored at $4^{\circ}C$ and upper (0-7 cm) positioning samples of box stored at 12 and $25^{\circ}C$ with electron beam was completely inhibited due to increase peroxidase and indole acetic acid (IAA) oxidase activity. Also, all samples with electron beam such as hardness, pH, sugar content, weight loss, and vitamin C and dacarotene content did not differ from that of the control. Therefore, if electron beam will be irradiated to sweetpotato roots above 0.1 kGy before packing, it will effectively inhibit their sprouting stored at $25^{\circ}C$ without the change of food quality characteristics.

• Journal of the Korean Society for Precision Engineering
• /
• v.33 no.5
• /
• pp.419-425
• /
• 2016

A powder spreading phenomenon is one of disadvantageous characteristics of the powder bed fusion process using electron beams. The powder spreading phenomenon can be controlled using a pre-heating process of metallic powders. The aim of this paper was to investigate the preheating process of Stellite21 powder using electron beams. Powder spreading experiments were performed to examine the influence of process parameters on the spreading behaviors of Stellite21 powder. Powder heating experiments were carried to investigate the effects of the focusing current of the electron beam on the quality of the heated region. Using the results of the powder spreading and heating experiments, an appropriate combination of process parameters was obtained. The pre-heating experiment of Stellite21 was performed using the estimated combination of process parameters. The results of preheating experiments showed that the preheated Stelllite21 layer with desired characteristics can be created when the estimated combination of process parameters is applied.

• Journal of Korean Society of Environmental Engineers
• /
• v.22 no.7
• /
• pp.1225-1232
• /
• 2000

This study was carried out to define the effect of electron beam irradiation on the physico-chemical characteristics of sewage sludges. The experimental evidence showed that both pH and alkalinity of irradiated sludge were generally increased as the dose of irradiation increased. It was found that the soluble protein concentration (SPC) and soluble chemical oxygen demand (SCOD) from the sludge right after electron beam irradiation at 3kGy(kilo-joule/kg) increased 2.2 times and 10 times respectively more than those sludges without electron beam treatment. This highly solubilized organics could be resulted in a good soluble substrate for the subsequent anaerobic digestion process. The specific resistance of filtration (SRF) tests showed that sludge dewaterability under electron beam irradiation at 6kGy was found to be 8.8 times higher than that of unirradiated sludge. The sludge dewaterability seemed to be directly related to the dosage of electron beam irradiation up to 10kGy. However, the efficiency of sludge dewaterability tended to be smaller with higher applied irradiation dose. In comparing treatments by different inorganic chemical conditioner with irradiated and unirradiated sludges, it appeared that the dewaterability with irradiated sludge was approximately 4-10 times better that that of unirradiated sludge. Even electron beam treatment itself could replace the result from the sludge conditioned with inorganic chemical coagulants.

• The Journal of Korean Society for Radiation Therapy
• /
• v.11 no.1
• /
• pp.73-78
• /
• 1999

In general, the patients of the head and neck cancer are treated with 4MV photon beam up to prescribed dose, but spinal cord should be excluded in the treatment field. When its absorbed dose is limited at the tolerance dose. In case of the patients who has the positive posterior neck nodes need a boost electron beam treatment to the prescribed dose. In that case, the anatomical structure of the neck and the physical structure of the standard electron cone interrupt to allow proper access to the disease site. Therefore, we extended treatment SSD for the remove of the those hindrances. In this study, we evaluated the dosimetric variation of the standard electron cone for the extended SSD, from 100cm to 120cm, 5 cm increment, and compare to the custom-made electron cone. As a result, the $\%$ depth dose, the point of maximum dose and the range of maximum were changed within the $2\%$. The penumbra width was increased from 1.0cm to 2.0cm. However, the dosimetric characteristics of the custom-made electron cone was very similar to that of the 100cm SSD standard electron cone and due to its characteristic of physical structure, patients didn't need re-positioning after photon beam treatment, therefore accurate treatment was possible, we conclude that the custom-made electron cone was very useful for the clinical practice.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.35 no.6
• /
• pp.774-779
• /
• 2006

The commercial green tea leaves were packaged with polyethylene film and irradiated by electron beam at doses of 0, 5, 10, 20, and 30 kGy. After irradiation, green teas were prepared by soaking the leaves in water (1 g/100 mL) at $75^{\circ}C$ for 10 min, and the physicochemical characteristics of green tea were determined. Electron beam irradiation decreased total phenol contents (TPC), total flavanol contents (TFC), ascorbic acid contents (AAC). Irradiation at dose of 20 kGy decreased TPC, TFC, and AAC from 223.46, 32.50, and 6.03 mg/g to 202.88, 31.16, and 5.57 mg/g, respectively, compared with non irradiated control. Electron beam irradiation also decreased catechins, caffeine, and nitrite scavenging activity of green tea. However, the changes of overall color and radical scavenging activity of irradiated green tea were negligible.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
• /
• 2004.04a
• /
• pp.508-512
• /
• 2004

An ultra-sharp tungsten electrode for field emission was manufactured by using an electrochemical etching method, and its beam characteristics were investigated. KOH and NaOH were the electrolytes used in this research, and the taper length of the tip varied form 150 $\mu\textrm{m}$ to 250 $\mu\textrm{m}$ according to the applied voltage and the concentration of the electrolyte. The electron-beam stability was measured to be within 5% for a total emission current of 5 ${\mu}\textrm{A}$ during 4 hours of operation, and the Ignition voltages were found to be ∼300 V. The tip radius was experimentally found to be 250${\AA}$ from a linear fitting of Fowler-Nordheim plots, which was in remarkably good agreement with that of the image size from scanning ion-microscopy.