• 전기의세계
• /
• v.29 no.2
• /
• pp.118-128
• /
• 1980

The properties of plasmas produced by high power glass laser were investigated with various methods of diagnostics. Electron temperature was estimated by measurement of soft X-ray, and ion temperature was estimated by measurement of the time-of-flight of ion. The measurement of incident and reflected laser light, and Schlieren and shadowgragh methods were also used. No influence of laser pulse duration on the temperature was observed in the case of durations 2, 4 and 10 nsecs. The effective heating of plasma occurred in about 2 nsec of beginning of incident laser pulse. The experimental results for fast rising laser pulse were discussed and the influence of resetime of laser pulse on the heating of plasma was described. Neutrons produced by irradiating laser beam to solid deuterium target were detected.

• 한국지구물리탐사학회:학술대회논문집
• /
• 2003.11a
• /
• pp.695-702
• /
• 2003

In this study, an experimental apparatus has been designed and set-up to analyse the dissociating phenomena of hydrate in porous rock using electric heating method supplied at downhole. The electric heat injecting experiments have been performed to investigate the heat transfer within the core, the dissociating phenomena of hydrate, and the productivities of dissociated gas and water. These experiments were under constant heat injecting method as well as preheating methods. From the experimental results, it is seen that the hydrates is dissociated along the phase equilibrium curve and dissociation of hydrate is accelerated with heat. The injected heat is consumed for the dissociation and also it is lost together with outflow of the dissociated gas and water. From the investigation of gas producing behavior for various heat injecting methods, as the injected heat is greater, dissociation is accelerated faster at outlet and hence the initial gas production becomes higher. Also, it is shown that the initial gas productivity under the constant heating method is better, however, the energy efficiency is low because of smaller amount of the produced gas comparing to the amount of heat injected. In the experiments of preheating method, it was seen that gas production only initial stage is different with the preheating time, but the producing behaviors of gas production are similar.

• Korean journal of food and cookery science
• /
• v.19 no.5
• /
• pp.555-561
• /
• 2003

The purpose of this study was to analyze the microbiological hazards of dried fish (Jwieochae, Ojingeochae and Bugeochae), and to apply pretreatment methods to increase the safety of cooked dried fish within foodservice establishments. Microbiological inspections were conducted on Total Plate Count, Coliforms, E. coli, E. coli O157:H7, Staphylococcus aureus, Salmonella spp. and Listeria monocytogenes. The study results are summarized as follows. According to the Hazard analysis, there are many problems showing high numbers in terms of Total Plate Count and Coliforms, which were both well over acceptable standard levels. E. coli and Staphylococcus aureus were detected at certain foodservice establishments, while E. coli O157:H7, Salmonella spp. and Listeria monocytogenes were not detected at all. By applying various pretreatment methods, such as washing, blanching, pan frying and microwave heating, the levels of microbiological hazards were able to be controlled and lowered. Blanching was the most effective method, followed by panfrying, microwave heating and washing. The Total Plate Counts gradually decreased with increasing number of times washed and seconds panfried. From these results, it is concluded that to guarantee food safety, cooked dried fish raw materials should be kept hygienically and appropriate pretreatment methods applied before cooking.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.24 no.5
• /
• pp.365-371
• /
• 2019

This study shows the feasibility of the parameter of the 1st RC parallel equivalent circuit as a factor of the heat generation of lithium-ion cell. The internal resistance of a lithium-ion cell consists of ohmic and polarization resistances. The internal resistances at various SOCs of the lithium-ion cell are obtained via an electrical characteristic test. The internal resistance is inversely obtained through the amount of heat generated during the experiment. By comparing the resistances obtained using the two methods, the summation of ohmic and polarization resistances is identified as the heating factor of lithium-ion battery. Finally, the amounts of heat generated from the 2C, 3C, and 4C-rate discharge experiments and the COMSOL multiphysics simulation using the summation of ohmic and polarization resistances as the heating parameter are compared. The comparison shows the feasibility of the electrical parameters of the 1st RC parallel equivalent circuit as the heating factor.

• KIEAE Journal
• /
• v.8 no.6
• /
• pp.3-10
• /
• 2008

Since fire was founded in the world, human races have invented various heating methods. Ondol is traditional heating method in Korea. It is very the important work to trace the history and characteristics of Ondol which originated and was developed in the Korean peninsula. Especially, the study on Ondol will contribute to improving the present heating methods and predicting future ones. In this paper, we shall study through the analysis of documents such as oriental documents, the document of Choseon dynasty, European documents and American documents. In order to discover the origins of Ondol as one of the excellent heating method all over the world, This study aims at identifying the history and characteristics of Ondol in the Korean peninsula, through document analysis. Results of this study are as follows. 1) The first document about Ondol is Sookyongjoo(水經注), Chinese ancient geography book. Contents recorded in the book include the description related to Ondol at Kwankyesa temple which was located at the border land between Gogooryo(ancient Korea) and the northeast of China. 2) Ondol was popular heating method in Gogooryo(ancient Korea) and it was used in not only Gogooryo but also Silla Kingdom and Beakje Kingdom. Thereafter, it was also used widely in Goryo dynasty and Choseon dynasty. Thereby we know that Ondol has been used as a heating method for a long time in the Korean peninsula. 3) Ondol was covered with a floor paper since the beginning of Choseon dynasty. the paper made room clean and impacted on Korean life style. Because the floor was clean and warm, Koreans thus took off shoes and sat on the floor. 4) Ondol was spreaded to Jeju island in Korea before 16th century but wasn't used widely there. The reason was that Ondol was rare high class heating system and the weather was warm in Jeju island. 5) The overspreading of Ondol caused that poor people built roughly Ondol in the last of Choseon dynasty. So, the quality of Ondol gradually became lower and lower. 6) A westerner was impressed by the novelty of Ondol and Frank Lloyd Wright had played an important role to update and spread Ondol widely all over the world. Hailing Ondol as the ideal heating system, Frank Lloyd Wright began incorporating it in his buildings back in the U.S. and even invented a modified ondol system, using hot water running through pipes instead of the hot exhaust through flues.

• International Journal of Highway Engineering
• /
• v.17 no.2
• /
• pp.31-37
• /
• 2015

PURPOSES : To design a pre-heater for warm in-place recycling equipment, three different heating systems were evaluated to determine their thermal efficiency. METHODS: In this study, a $30cm{\times}30cm{\times}15cm$ wheel-tracking specimen was used to measure the inner temperature as a function of the heating system. The inner temperature of the specimen was measured with a data logger at the surface, and at depths of 1cm, 2cm, 3cm, 4cm, and 5cm. To evaluate the thermal efficiency, the researchers used three different types of equipment, namely, IR, a heating wire, and a gas burner. RESULTS: The IR heating system exhibits a higher level of performance than the others to achieve the target temperature at a depth of 5cm in the specimen. The gas burner system was capable of heating the surface to a temperature of up to $600^{\circ}C$. The other types, however, cannot heat the surface up to 600. The thermal efficiencies were measured based on the laboratory conditions. CONCLUSIONS: To find the most effective system for application to the development of a pre-heater for warm in-place recycling, various systems (IR, heating wire, gas burner) were examined in the laboratory. As a result, it was found that the hot plate of a gas burner system provides the highest temperature at the surface of the asphalt but, of all the systems, the IR system provides the best internal temperature increase rate. Furthermore, a gas burner can age the asphalt binder of the surface layer as a result of the high temperature. However, the gas burner cannot attain the target temperature at 5cm. The IR system, on the other hand, is effective at increasing the internal temperature of asphalt.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.16 no.6
• /
• pp.87-94
• /
• 2017

Hot stamping processes are possible for tensile strength 1.4 GPa but the strength reduction is appeared from the cooling performance unbalance. And the strength of roll forming process is below than that of hot stamping process owing to using the steel which is lower strength of boron steel. In this study, We provide roll forming process asssisted high-frequency induction heating to solve the problem of conventional one. The experiments were carried out at under various sill side part conditions: high-frequency induction heating conditions of 15, 18, 21, 24, 27 and 30 kW. The high-frequency induction heating temperature was checked with Infrared camera and the sill side parts of mechanical properties and microstructure were measured. The heating temperature of high frequency induction was measured to max $850^{\circ}C$ under the coil power of 30 kW. The tensile strength was 1.5 GPa and hardness was 490 Hv. The martensite structure was discovered under coil power of 30 kW. The weight of steel material sill side having thickness 1.5 mm and the boron steel sill side having thickness 1.2 mm were compared to weight effect. The boron steel sill side reduced 11.5% compared to steel. Consequently, manufacturing process of 1.5 giga-grade's sill side part was successfully realized by the roll forming assisted high-frequency induction heating methods.

• Journal of the Korean Wood Science and Technology
• /
• v.45 no.4
• /
• pp.409-418
• /
• 2017

This work attempted to manufacture glued-laminated timber (Glulam) bonded with melamine-urea-formaldehyde (MUF) resin adhesives at various melamine contents from 20% to 50% under high frequency (HF) heating for a very short time. Two preparation methods were employed to prepare MUF resin adhesives with different melamine contents: one-batch method of synthesizing MUF resins in a single batch, and two-batch method of mixing urea-formaldehyde (UF) resin with melamine-formaldehyde (MF) resin that had been synthesized separately. As the melamine content increased, the gelation time and peak temperature of MUF resins decreased. The adhesion performance of plywood showed that the one-batch MUF resin adhesive with 50% melamine content only satisfied the standard requirement of water resistance. Thus, the one-batch MUF resin adhesive with 50% melamine content was applied for bonding wood lamina from four softwood species such as Japanese larch, Korean red pine, Korean pine and Japanese cedar to manufacture Glulam under HF heating. All Glulam samples bonded with the one-batch MUF resin adhesives with 50% melamine content except those from Korean Red Pine satisfied the requirement in water soaking or boiling water delamination test as an exterior grade Glulam. The presence of rosin in Korean Red Pine was believed to be responsible for its poor adhesion. These results showed that the one-batch MUF resin adhesives with 50% melamine content provided acceptable water resistance with exterior grade Glulam manufactured under HF heating.

• Preventive Nutrition and Food Science
• /
• v.3 no.3
• /
• pp.234-240
• /
• 1998

This study attempted to determine the effect of various thawing methods and storage periods on the quality of froen cooked rice. Frozen cooked rice was thawed at four different methods, such as pressure cooking, conventional cooking, microwave heating and thawing at room temperature after 10 days, 30days and 90 days frozen storage. We conducted a physico-chemical analysis (moisture content, dehydration rates, degree of gelatinization, color value and texture) and sensory evalution on the frozen-thawed cooked rice. The study showed that there were no significant differences on the quality characteristics of frozen-thawed cooked rice during the storage period of 90 days. However, the thawing method of pressure cooking caused high moisture content, rapid dehydration rates, and a high degree of gelatinization on the cooked rice. Thus, the desirabililty for the rice diminished becaused of the excess moisture content and the change of appearance and testure in the rice due to the high temperature. There were similiar quality characteristics to the cooked rice after forzen-thawing whether by conventional cooking or by microwave heating and just after cooking. Thawing at room temperature also caused a significant decrease in quality characteristics.

• Journal of the Korean Society of Food Culture
• /
• v.16 no.4
• /
• pp.323-329
• /
• 2001

This study was carried out to observe the character change of expanded rice grain for Salyeotgangjung at various gelatinization methods. The expansion and structure change of rice grain was different at conditions of heating methods and gelatinization, respectively. The boiling showed good expansion compared to other heating methods by electric rice-cooker, pressure cooker, and steam cooker. There was not difference in expansion of rice grain between the boiling and the boiling after soaking. Rice grain did greatly expand as the boiling time was extended. But the quality for Salyeotgangjung would be not good because of crack of expanded rice grain surface when the boiling time was too long.