• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.22 no.5
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• pp.818-823
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• 2013

In the process of sterilization during the manufacture of beverages, both the treatment time and the temperature influence the beverage taste and flavor. Therefore, to improve the beverage quality, a nonthermal sterilization method is preferred to a high-temperature one. A nonthermal method, ultrasonic treatment by shock waves from cavitation, has been known to have a sterilizing effect. In this study, to observe the effect of ultrasonic frequency and treatment time on beverage quality, batch type ultrasonic equipment was fabricated and tested. Further, to evaluate the applicability of this ultrasonic method to an in-situ process, flow type ultrasonic heptagonal equipment was fabricated and then used to perform a sterilization experiment. Subsequently, the sterilizing effect was measured under ultrasonic and low-temperature ($55^{\circ}C$) treatments. Based on the obtained results, ultrasonic sterilization technology that can be applied for treatments at flow rates of up to 3 L/min was developed.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2008.10a
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• pp.194-195
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• 2008

• Korean Journal of Food Science and Technology
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• v.29 no.6
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• pp.1202-1207
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• 1997

Inactivation of Leuconostoc sp. isolated from kimchi using carbon dioxide under pressure was investigated in terms of operating parameters in order to evaluate its feasibility as a novel nonthermal process. Inactivation rates increased with increasing pressure, temperature and exposure time, but with decreasing working volume. Microbial reduction of 3 log cycles was achieved within 150 min under a $CO_2$ pressure of $60\;kg/cm^2$ at 30^{\circ}C$. It was confirmed that microbial inactivation by the high pressure $CO_2$ was governed essentially by the characteristic of $CO_2$ mass transfer and thus penetration of $CO_2$, into cells was a rate limiting step to determine efficiency of the inactivation process. The experimental results suggested that the high pressure $CO_2$ treatment could be used as one of the effective nonthermal methods for preserving foods.

• Journal of the Korean Society of Combustion
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• v.5 no.2
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• pp.37-50
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• 2000

In the present study, a systematic chemical kinetic calculations were made to investigate the augmentation of $NO-NO_2$ conversion due to the addition of various hydrocarbons (methane, ethylene, ethane, propylene, propane) in the nonthermal plasma treatment. It is included in the present conclusion that the reaction between hydrocarbon and oxygen radicals induced by electron collision, is believed to be a primarily process for triggering the overall NO oxidation and the eventual NOx reduction. Upon the completion of the initiating step, various radicals (OH, $HO_2$ etc.) successively are produced by hydrocarbon decomposition form the primary path of $NO-NO_2$ conversion. When the initiating step is not activated, hydrocarbon consumption rate appeared to be very low, thereby the targeted level of NO conversion can only be achieved by the addition of more input energy. Present study showed ethylene and propylene to have higher affinity with O radical under all conditions, thereby both of these hydrocarbons show very fast and efficient $NO-NO_2$ oxidation. It was also shown that propylene is superior to ethylene in the aspect of NOx removal.

• Journal of The Korean Astronomical Society
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• v.37 no.5
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• pp.447-454
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• 2004

During the hierarchical formation of large scale structure in the universe, the progressive collapse and merging of dark matter should inevitably drive shocks into the gas, with nonthermal particle acceleration as a natural consequence. Two topics in this regard are discussed, emphasizing what important things nonthermal phenomena may tell us about the structure formation (SF) process itself. 1. Inverse Compton gamma-rays from large scale SF shocks and non-gravitational effects, and the implications for probing the warm-hot intergalactic medium. We utilize a semi-analytic approach based on Monte Carlo merger trees that treats both merger and accretion shocks self-consistently. 2. Production of $^6Li$ by cosmic rays from SF shocks in the early Galaxy, and the implications for probing Galaxy formation and uncertain physics on sub-Galactic scales. Our new observations of metal-poor halo stars with the Subaru High Dispersion Spectrograph are highlighted.

• Journal of Dairy Science and Biotechnology
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• v.33 no.3
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• pp.223-229
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• 2015

Milk is a food with high nutritional value as it contains abundant water, proteins, vitamins, lactose, fat, minerals, enzymes, etc. However, in order to make milk suitable for intake, it should be thermally treated to eliminate microbiologically hazardous factors. Heat treatment is an essential sanitation process for milk, but various precautions must be taken in order to process and preserve it. Therefore, various techniques should be developed to minimize the nutrient loss and to ensure that milk is safe for consumption, conservation, and distribution. However, the existing thermal pasteurization methods are harmful and increase the nutrient loss; moreover, no new thermal pasteurization methods are being researched that are safe for the human health and minimize the nutrient loss. Hence, this study aims to review new processes for thermal (low temperatures) and no thermal pasteurization methods that can minimize the nutrient loss during milk pasteurization.

• Journal of The Korean Astronomical Society
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• v.46 no.1
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• pp.49-63
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• 2013

Nonthermal radiation from supernova remnants (SNRs) provides observational evidence and constraints on the diffusive shock acceleration (DSA) hypothesis for the origins of Galactic cosmic rays (CRs). Recently it has been recognized that a variety of plasma wave-particle interactions operate at astrophysical shocks and the detailed outcomes of DSA are governed by their complex and nonlinear interrelationships. Here we calculate the energy spectra of CR protons and electrons accelerated at Type Ia SNRs, using time-dependent, DSA simulations with phenomenological models for magnetic field amplification due to CR streaming instabilities, Alf$\acute{e}$enic drift, and free escape boundary. We show that, if scattering centers drift with the Alf$\acute{e}$en speed in the amplified magnetic fields, the CR energy spectrum is steepened and the acceleration efficiency is significantly reduced at strong CR modified SNR shocks. Even with fast Afv$\acute{e}$nic drift, DSA can still be efficient enough to develop a substantial shock precursor due to CR pressure feedback and convert about 20-30% of the SN explosion energy into CRs. Since the high energy end of the CR proton spectrum is composed of the particles that are injected in the early stages, in order to predict nonthermal emissions, especially in X-ray and ${\gamma}-ray$ bands, it is important to follow the time dependent evolution of the shock dynamics, CR injection process, magnetic field amplification, and particle escape. Thus it is crucial to understand the details of these plasma interactions associated with collisionless shocks in successful modeling of nonlinear DSA.

• 한국연소학회:학술대회논문집
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• 2000.12a
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• pp.33-46
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• 2000

In the present study, a systematic chemical kinetic calculations were made to investigate the augmentation of NO-$NO_2$ conversion due to the addition of various hydrocarbons (methane, ethylene, ethane, propene, propane) in the nonthermal plasma treatment. It is included in the present conclusion that the reaction between hydrocarbon and oxygen radicals induced by electron collision, is believed to be a primarily process for triggering the overall NO oxidation and the eventual NOx reduction. Upon the completion of the initiating step, various radicals (OH, $NO_2$ etc.) successively produced by hydrocarbon decomposition form the primary path of NO-$NO_2$ conversion. When the initiating step is not activated, hydrocarbon consumption rate appeared to be very low, thereby the targeted level of NO conversion can only be achieved by the addition of more input energy. Present study showed ethylene and propene to have higher affinity with 0 radical under all conditions, thereby both of these hydrocarbons show very fast and efficient NO-$NO_2$ oxidation. It was also shown that propene is superior to ethylene in the aspect of NOx removal.

• 한국연소학회:학술대회논문집
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• 2000.05a
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• pp.178-188
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• 2000

In the present study, a systematic chemical kinetic calculations were made to investigate the augmentation of $NO-NO_{2}$ conversion due to the addition of various hydrocarbons (methane, ethylene, ethane, propene, propane) in the nonthermal plasma treatment. It is included in the present conclusion that the reaction between hydrocarbon and oxygen radicals induced by electron collision, is believed to be a primarily process for triggering the overall NO oxidation and the eventual NOx reduction. Upon the completion of the initiating step, various radicals (OH, $HO_{2}$ etc.) successively produced by hydrocarbon decomposition form the primary path of $NO-NO_{2}$ conversion. When the initiating step is not activated, hydrocarbon consumption rate appeared to be very low, thereby the targeted level of NO conversion can only be achieved by the addition of more input energy. Present study showed ethylene and propene to have higher affinity with 0 radical under all conditions, thereby both of these hydrocarbons show very fast and efficient $NO-NO_{2}$ oxidation. It was also shown that propene is superior to ethylene in the aspect of NOx removal.

• Journal of the Korean Applied Science and Technology
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• v.31 no.4
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• pp.541-548
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• 2014

This study was performed to obtain high conversion efficiency of $C_7H_8$ using non-thermal plasma and metal-supported catalyst. Adsorption-desorption characteristics of toluene was performed using 4A type (Zeolite) filled in a concentration reactor. Through this test, it was found that the concentration reactor has 0.020 g/g of adsorption capacity (at ambient temperature and pressure) and 3,600 ppm of desorption property at $150^{\circ}C$ (with in 20 min). In case of developed catalyst, toluene decomposition rate of Pd-AO (Pd coated catalyst) was better than Pd/Cu-AO and Pd/Ag-AO (Pd/Ag composite metal catalyst). Developed non-thermal plasma system was obtained flame amplification effect using injection process of desorbed tolune, and 98% of removal efficiency.