• Food Science and Biotechnology
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• v.15 no.3
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• pp.374-379
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• 2006

This study was carried out to investigate the physicochemical properties of frozen pork muscle which has been thawed using the ohmic thawing process, and to establish the optimal ohmic power intensity. The samples were frozen at $-40^{\circ}C$ and thawed at 0, 10, 20, 30, and 40 V by ohmic thawing. Increasing ohmic power intensity correlated with increased thawing rates. The relationship between ohmic power intensity and thawing rate can be represented as a polynomial function. The pH value decreased with increasing ohmic power intensity (p<0.05). With regard to color measurement, the $L^*$, a, and b values of thawing at all ohmic power intensities were not significantly different. The water holding capacity showed a peak value of 41.62% with an ohmic thawing intensity of 30 V. Cooking losses were lowest at the lowest ohmic thawing intensity of 10 V. Thiobarbituric acid reactive substance (TBARS) levels with all thawing processes were slightly higher than that of the control (p<0.05). Increasing ohmic power intensity did not tend to change the total volatile basic nitrogen (TVBN) value.

• Food Science of Animal Resources
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• v.26 no.2
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• pp.223-228
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• 2006

This study was carried out to investigate the effects of ohmic power intensity on the physico-chemical properties of hamburger patties. Six different ohmic power intensities (0, 10, 20, 30, 40, and 50V) were delivered by controlling the power with the sine wave at 50Hz. The ohmic power intensity influenced the thawing rate, and increasing ohmic power intensity increased the thawing rate. The faster thawing rate was obtained at higher ohmic power intensity (50V) with 0.5% NaCl added meat patties in comparison to no NaCl added hamburger patties. The pH values of all patties were not significantly different with increasing ohmic power intensity (p<0.05). Increasing thawing rate did not tend to improve the water holding capacity (WHC) of all patties by ohmic thawing. Cooking losses were almost the same regardless of increasing ohmic power intensity. Increasing ohmic power intensity tended to increase the thiobarbituric acid reactive substance (TBARS) levels. TBARS levels of all hamburger patties without NaCl were significantly higher than that of 0.5% NaCl added hamburger patties (p<0.05) at higher ohmic intensity (50V). In conclusion, these results indicated that a higher ohmic power intensity at 50 V induced the lipid oxidation of all patties.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.16 no.5
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• pp.390-396
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• 2003

As the design rule of device continued to shrink, the contact resistance in small contact size became important. Although the conventional TiN/Ti structure as a ohmic layer has been widely used, we propose a new TiN/Co film structure. We characterized a contact resistance by using a chain pattern and a KELVIN pattern, and a leakage current determined by current-voltage measurements. Moreover, the microstructure of TiN/ Ti/ silicide/n$\^$+/ contact was investigated by a cross-sectional transmission electron microscope (TEM). The contact resistance by the Co ohmic layer showed the decrease of 26 % compared to that of a Ti ohmic layer in the chain resistance, and 50 ％ in KELYIN resistance, respectively. A Co ohmic layer shows enough ohmic behaviors comparable to the Ti ohmic layer, while higher leakage currents in wide area pattern than Ti ohmic layer. We confirmed that an uniform silicide thickness and a good interface roughness were able to be achieved in a CoSi$_2$ Process formed on a n$\^$+/ silicon junction from TEM images.

• The Korean Journal of Food And Nutrition
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• v.24 no.4
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• pp.740-745
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• 2011

Ohmic heating uses electric resistance heat which occurs equally and rapidly inside food when an electrical current is passed throught. In this study, we observed the physical & chemical characteristics changes which occurs in soybean protein during heating denaturation by using ohmic and conventional heating. After the ohmic heating process, we could not find any change of the primary protein structure in the denaturated soy protein samples. However, the rate of imbibed water(RIW) of the ohmic samples was 2 times faster than that of the conventional samples. Also the ANS-surface hydrophobicity was decreased, which is very closely related to RIW. In the differential scanning calorimeter(DSC) analysis result, all 7S soyprotein fraction samples were completely denaturated by ohmic and conventional heating. However, the 11S samples were completely denatured only by ohmic heating. According to the DSC result, we decided that soyprotein was damaged by temperature and electrical current during ohmic heating. The damage of electrical current was a cause of the characteristic changes.

• Journal of Microbiology and Biotechnology
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• v.12 no.2
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• pp.183-188
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• 2002

The ohmic heating of foods for sterilization provides a shorter come-up time compared to conventional thermal processes. The electric fields as well as the heat generated by ohmic heating facilitate germicidal effects. In the present study, the effect of ohmic heating on the structure and permeability of the cell membrane of yeast cells, Saccharomyces cerevisae, isolated from Takju (a traditional Korean rice-beer), was investigated. The ohmic heating was found to translocate intracellular protein materials out of the cell wall, and the amount of exuded protein increased significantly as the electric field increased from 10 to 20 V/cm. As higher frequencies were applied, more materials were exuded. Compared to conventional heating, more amounts of proteins and nucleic acids were exuded when these cells were treated with ohmic heating. The molecular weights of the major exuded proteins ranged from 14 kDa to 18 kDa, as analyzed by Tricine-SDS PAGE. A TEM study also confirmed the leakage of cellular materials, thus indicating irreversible damage to the cell wall by ohmic heating. It was, therefore, concluded that the electric fields generated by ohmic heating induced electroporation, causing irreversible damage to the yeast cell wall and promoting the translocation of intracellular materials.

• The Korean Journal of Food And Nutrition
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• v.28 no.1
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• pp.126-133
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• 2015

Ohmic heating uses electric resistance heat which occurs equally and rapidly inside food when the electrical current is transmitted into. Prior to the study, we have researched the potato starch's thermal property changes during ohmic heating. Comparing with conventional heating, the gelatinization temperature and the range of potato starch treated by ohmic heating are increased and narrowed respectively. This result is appeared equally at wheat, corn and sweet potato starch. At this study, we treated potato, wheat, corn and sweet potato starch by ohmic/conventional method and observed change of external structure by microscope and internal structure by X-ray diffractometer. Conventional heated at $55^{\circ}C$ potato starch was not external structural changes. But ohmic heated potato starch is showed largely change. Some small size starch particle were broken or small particles are made of larger particle together or small particles caught up in the large particle. Changes in ohmic heated potato starch at $60^{\circ}C$ was greater. The inner matter came to an external particle burst inside and only the husk has been observed. The same change was observed in the rest of the starch. The change of internal structure of potato starch was measured using X-ray diffraction patterns. There was no significant difference between ohmic and conventional heating at $55^{\circ}C$. But almost every peak has disappeared ohmic at $60^{\circ}C$. Especially $5.4^{\circ}$ peak to represent the type B was completely gone. When viewed from the above results, external changes with change in the internal crystal structure of the starch particles were largely unknown to appear. In conclusion, during ohmic heating changes of starch due to the electric field with a change in temperature by the heating was found to have progressed at the same time.

• Korean Journal of Materials Research
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• v.13 no.7
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• pp.465-472
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• 2003

Pd/Ge/Ti/Pt and Pd/Ge/Pd/Ti/Au ohmic contacts to n-type InGaAs were investigated for applications to AlGaAs/GaAs HBT emitter ohmic contacts. In the Pd/Ge/Ti/Pt ohmic contact minimum specific contact resistivity of $3.7${\times}$10^{-6}$ $\Omega$$\textrm{cm}^2$ was achieved by rapid thermal annealing at $^400{\circ}C$/10 sec. In the Pd/Ge/Ti/Au ohmic contact, minimum specific contact resistivity of $1.1${\times}$10^{-6}$ $\Omega$$\textrm{cm}^2$ was achieved by annealing at 40$0^{\circ}C$/10 sec but the ohmic performance was degraded with increasing annealing temperature due to the reaction between the ohmic contact materials and the InGaAs substrate. However, non-spiking planar interface and relatively good ohmic contact (high-$10^{-6}$ /$\Omega$$\textrm{cm}^2$) were maintained after annealing at $450^{\circ}C$/10 sec. Therefore, these thermally stable ohmic contact systems are promising candidates for compound semiconductor devices. RF performance of the AlGaAs/GaAs HBT was also examined by employing the Pd/Ge/Ti/Pt and Pd/Ge/Pd/Ti/Au systems as emitter ohmic contacts. Cutoff frequencies were 63.5 ㎓ and 65.0 ㎓, respectively, and maximum oscillation frequencies were 50.5 ㎓ and 51.3 ㎓, respectively, indicating very successful high frequency operations.

• The Korean Journal of Food And Nutrition
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• v.27 no.1
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• pp.112-119
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• 2014

Ohmic heating uses electric resistance heat which occurs equally and rapidly inside food when the electrical current is transmitted into. Prior to the study, we have researched the potato starch's thermal property changes during ohmic heating. Comparing with conventional heating, the gelatinization temperature and the range of potato starch treated by ohmic heating are increased and narrowed respectively. Herein, we have studied thermal property changes of wheat, corn, potato and sweet potato starch by ohmic heating as well as conventional heating. And then we measure the water holding capacity of starches. Annealing of starch is a heat treatment method heated at 3~4% below the gelatinization point. This treatment changes the starch's thermal property. In the DSC analysis of this study, the $T_o$, $T_p$, $T_c$ of all starch levels have increased, and the $T_c$-$T_o$ narrowed. In the ohmic heating, the treatment sample is extensively changed but not with the conventional heating. From the ohmic treatment, increases from gelatinization temperature are potato ($8.3^{\circ}C$) > wheat ($5.3^{\circ}C$) > corn ($4.9^{\circ}C$) > sweet potato ($4.5^{\circ}C$), and gelatinization ranges are potato ($7.9^{\circ}C$), wheat ($7.5^{\circ}C$), corn ($6.1^{\circ}C$) and sweet potato ($6.8^{\circ}C$). In the case of conventional treatment, water holding capacity is not changed with increasing temperature but the ohmic heating is increased. Water holding capacity is related to the degree of gelatinization for starch. This result show that when treated with below gelatinization temperature, the starches are partly gelatined by ohmic treatment. When viewing the results of the above, ohmic treatment is enhanced by heating and generating electric currents to the starch structure.

• Proceedings of the Korea Association of Crystal Growth Conference
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• 1997.06a
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• pp.231-236
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• 1997

To improve electrical properties and uniformity of high-low doped n-type GaAs, new ohmic contacts with a low-resistance and the superior uniformity was developed using a concept of hybrid ohmic contact. The hybrid ohmic contact displayed good surface and interface morphology and had minimum contact resistivity of 3${\times}$10-6 $\Omega$$\textrm{cm}^2$ in a wide annealing temperature ranged from 340$^{\circ}C$ to 420$^{\circ}C$, which was much wider than that of conventional ohmic contacts. The microstructural analysis showed that the Pd/Ge ohmic contact at low annealing temperature (∼300$^{\circ}C$) and also annealing temperature (∼400$^{\circ}C$), resulting ij hybrid ohmic contacts.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.1061-1064
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• 2009

Through dark injection space-charge-limited current (DI-SCLC) and trap-free SCLC measurements, it has been demonstrated that an indium tin oxide (ITO)/buckminsterfullerene ($C_{60}$) electrode can form a quasi-Ohmic contact with N, N'-bis (naphthalen-1-yl)-N, N'-bis(phenyl) benzidine (NPB). The DI-SCLC results show a clear peak current along with a shift of the peak position as the field intensity varies, implying an Ohmic (or quasi-Ohmic) contact. A theoretical simulation of the SCLC also shows that ITO/$C_{60}$ forms an Ohmic contact with NPB. The Ohmic contact makes it possible to estimate the NPB hole mobility through the use of both DI-SCLC and trap-free SCLC analysis. This also contributes to a reduction in power consumption.