• Journal of the Semiconductor & Display Technology
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• v.23 no.1
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• pp.92-96
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• 2024

The application of the technology for forming Al₂O₃ thin films using ALD(atomic layer deposition) method is rapidly increasing in the semiconductor and display fields. In order to increase the efficiency of the ALD process in a mass production line, metallic by-products generated from the ALD process chamber must be effectively collected. By collecting by-products flowing out of the chamber with a cold trap device before they go to the vacuum pump, damage to the vacuum pump can be prevented and the work room can be maintained stably, resulting in increased process flow rate. In this study, a cold trap was installed between the ALD process chamber and the dry pump to measure and analyze by-products generated during the Al₂O₃ thin film deposition process. As a result, it was confirmed that Al and O elements were discharged, and the collection forms were two types: bulk and powder. And the binding energy peaked at 73.7 ~ 74.3 eV, the binding energy of Al 2p, and 530.7 eV, the binding energy of O 1s, indicating that the binding structure was Al-O.

• Journal of Korean Society of Environmental Engineers
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• v.31 no.11
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• pp.1025-1032
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• 2009

This study investigated a possibility to develop an adsorption process for volatile organic compounds (VOCs) of the solvent emitted during dry cleaning. Pitch activated carbon fiber (ACF) was chosen as an adsorbent of VOCs, and an electric swing adsorption process was utilized for the reproduction of the adsorbent after the completion of VOCs adsorption. Effects of ACF types and several solvents such as trichloroethylene (TCE) and toluene were examined on breakthrough curves and amounts of adsorbed VOCs. ACF was pretreated under various conditions in order to enhance the amounts of the adsorbed VOCs. Temperatures and voltages were measured for the reproduction of the ACF after full adsorption. ACF having micropores exhibited high adsorption of TCE, and high surface area of ACF could increase the adsorption property of toluene. In general, ACF could adsorb 41~54% TCE of the adsorbent weight. The increase of inlet VOCs concentration significantly decreased the breakthrough time and slightly lowered the amounts of adsorbed VOCs. Thus, ACF could effectively adsorb VOCs in low concentration in the feed stream. ACF pretreated by heat under vacuum showed excellent toluene adsorption with controlling oxygen functional groups on the ACF surface, which revealed that vacant carbon site could be the adsorption point of toluene. Most adsorbed toluene was desorbed at $150^{\circ}C$.

• Journal of the Korean Society of Food Science and Nutrition
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• v.40 no.9
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• pp.1307-1313
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• 2011

This study was conducted to evaluate the effects of irradiation temperature on the physicochemical and sensory properties of Tarakjuk, milk porridge. Tarakjuk was gamma-irradiated at different temperatures of $25^{\circ}C$ (in room), $4^{\circ}C$ (in ice), and $-20^{\circ}C$ (in dry ice) at a dose of 10 kGy, and then autoclaved at $120^{\circ}C$ for 15 min for comparison. pH and Hunter's color value of Tarakjuk were not changed by irradiation regardless of the temperature. However, the TBA (2-thiobarbituric acid) value decreased as irradiation temperature was decreased. The viscosity of Tarakjuk irradiated in dry ice was significantly higher than that irradiated at room temperature and in ice (p<0.05). For the sensory evaluation, there were no significant differences in overall acceptability between non-treated Tarakjuk and that irradiated in dry ice. Flavor pattern analysis using an electronic nose with a SAW (surface acoustic wave) sensor determined that the main peaks at retention times 3.88 and 7.34 sec were related with off-flavor induced by irradiation and unique flavor of Tarakjuk, respectively. These results indicated that irradiation at freezing temperature improved quality deterioration of Tarakjuk by gamma irradiation. However, sensory quality of Tarakjuk irradiated at freezing temperature was still lower than that of non-irradiated Tarakjuk. Therefore, further research is needed to improve the quality of Tarakjuk using combined treatment such as addition of antioxidants and vacuum packaging method.

• Journal of Venture Innovation
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• v.5 no.2
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• pp.85-99
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• 2022

Dryers becoming commercially available for experimental and industrial use are classified to general drying oven, hot-air dryer, vacuum dryer, freezing dryer, etc. and kinds of them are various from the function, size and volume, etc. But the moisture measurement is not applied although it is important factor for the quality control and the performance improvement of products, and then now is very passive because the weight is weighed arbitrarily after dry-end. Generally the method for measuring moisture is divided by a direct measurement method and a indirect measurement method, and the former such as the change of weight or volume on the front and rear of separation of moisture, etc. is mainly used. Relatively a indirect measurement is very limited to apply due to utilize measurement apparatuses using temperature conductivity and micro-wave etc. In this research, we easily designed the moisture measurement system using the open-source based Arduino, and monitored moisture fluctuations and weight profiles in the real-time without the effect of external environment. Concretely the temperature-humidity and load cell sensors were packaged into a drying oven and the various change values were measured, and their sensors capable to operate 60℃ and 80℃ were selected to suitable for the moisture sensitive materials and the food dry. And also the performance safety using the organic samples of banana, pear, sawdust could be secured because the changes of evaporation rate as the dry time and temperature, and the measurement values of load cell appeared stable response characteristics through repeated experiments. Hereafter we judge that the reliability can be improved increasingly through the expansion of temperature-humidity range and the comparative analysis with CFD(Computational Fluid Dynamics) program.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.8 no.2
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• pp.107-117
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• 1975

Alaska pollack caught in the Northern Pacific Ocean and frozen aboard vessel are skipped to the plant and processed into frozen fillets. In the present paper quality changes during thwaing, refreezing and storage at $-20^{\circ}C$ are discussed. Natural, running-water, vacuum and steam thawing were employed as thawing methods. And contact plate, air blast, immersion in dry ice-alcohol solution freezing and storage at $-5^{\circ}C$ were applied to refreeze the thawed fillets. As quality factors content of drip released, salt-extractable protein, VBN, DNA in the drip and pH were determined. In addition, bacteriological tests were also carried out along with the whole process. In thawing of round material, the vacuum thawing was more effective than any other method, resulting in drip, salt-extractable protein $(N\%)$, VBN and DNA as $4.4\%,\;1.82\%,\;16.21mg\%$ and $13.70\;{\mu}g/ml$, respectively. Storage at $-5^{\circ}C$ as refreezing method yielded lower in drip and DNA content but similar to or slightly higher in both salt-extractable protein and VBN, which might postulate that the quality of the frozen fillet depends not largely on the secondary freezing but on the conditions of thawing and primary freezing. It seemed that most of the bacterial flora in thawed fillet came from skin and viscera of fish, worker's hands, utensils and other processing facilities, since sanitary indicative bacteria were not detected in the frozen flesh of round Alaska pollack. Bacterial quality of fillet varied with thawing methods, vacuum thawing appeared more sanitative compared with other methods as natural, running-water, and steam thawing. Bacterial colonies isolated from the thawed fillet were composed of $73.8\%$ Gram negative rod shape, $4.9\%$ Gram positive rod shape, $18.0\%$ cocci, and $3.3\%$ yeast. Decreasing rate of coliform group of the fillet during the storage at $-20^{\circ}C$ for 30 days was more than $70\%$ and that of plate count was less than of coliform group.

• Journal of Electrical Engineering and Technology
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• v.1 no.3
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• pp.366-370
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• 2006

We investigated the negative differential resistance (NDR) property of self-assembled 4,4-di(ethynylphenyl)-2'-nitro-l-(thioacetyl)benzene ('nitro-benzene'), which has been well known as a conducting molecule [1], Self-assembly monolayers (SAMs) were prepared on Au (111), which had been thermally deposited onto pre-treated $(H_2SO_4: H_2O_2=3:1)$ Si, The Au substrate was exposed to a 1mM solution of 1-dodecanethiol in ethanol for 24 hours to form a monolayer. After thorough rinsing of the sample, it was exposed to a $0.1{\mu}M$ solution of nitro-benzene in dimethylformamide (DMF) for 30 min and kept in the dark during immersion to avoid photo-oxidation. Following the assembly, the samples were removed from the solutions, rinsed thoroughly with methanol, acetone, and $CH_2Cl_2$, and finally blown dry with $N_2$. Under these conditions, we measured the electrical properties of SAMs using ultra high vacuum scanning tunneling microscopy (UHV-STM) and scanning tunneling spectroscopy (STS) [2]. As a result, we confirmed the properties of NDR in between the positive and negative region.

• Korean Journal of Materials Research
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• v.14 no.3
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• pp.211-217
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• 2004

The oxidation behaviors of Ti-10Ta-10Nb alloy and Ti-6Al-4V alloy were studied in dry air atmosphere. Specimens were melted in consumable vacuum arc furnace and homogenized at $1050^{\circ}C$ for 24 h. Hot rolling was performed at $1000^{\circ}C$. Specimens of the alloys were oxidized as the temperature range $400~650^{\circ}C$ for 30 min. The oxidation behavior of the alloys was analysed by optical microscope, SEM/EDX, XRD, XPS and TGA. Immersion test was performed in 1% Lactic acid. In the microscope observation, oxide layer of Ti-10Ta-10Nb alloy was denser and thinner than Ti-6Al-4V's. The weight gains during the oxidation rapidly increased at the temperature above $600^{\circ}C$ in Ti-6Al-4V's alloy and$ 700^{\circ}C$ in Ti-10Ta-10Nb alloy. According to XRD results, oxide layers were composed of mostly $TiO_2$(rutile) phase. It was analysed that the passive film of the Ti alloys consisted of $TiO_2$ through X-ray photoelectron spectroscopy(XPS) analysis.

• Journal of the Korean Electrochemical Society
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• v.16 no.1
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• pp.1-8
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• 2013

This review article summarizes metal-assisted chemical etching (MAC etch or MACE), an anisotropic etching method for Si, and describes principles, main factors, and recent achievements in literature. In 1990, it was discovered that, with metal catalyst on surface and $H_2O_2$/HF as etchant, Si substrate can be etched anisotropically, in even in solution. In contrast to high-cost vacuum-based dry etching methods, MAC etch enables to fabricate a variety of high aspect ratio nanostructures through wet etching process.

• Journal of the Korean Home Economics Association
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• v.41 no.2
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• pp.107-121
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• 2003

This study was discussed the dyeing of wool and nylon fabrics with Chinese Scholar Tree extract. The extracts of Chinese Scholar Tree was prepared in the condition of heating at $95{\pm}5C$, for 1 hour and cooling to 40C. And then the extracts of color matter treate with vacuum concentration at $60{\pm}2^{\circ}C$, 30mmHg and dried with spray dryer. The dyeing of wool and nylon fabric in this experiment was also employed the mordant dyeing method such as pre-mordant, post-mordant and simultaneous mordant method. The mordanting agents used in this study were as followings ; aluminium potassium sulfate, copper(II) acetate monohydrate, chromium potassium sulfate$.$$7H_2O$, Tin(II) chloride dihydrate, iron(II)sulfate $7H_2O$. For an evaluation of the dyeing property of the mordanting agents, the pre-mordant method, the repeat dyeing and the fastness of the light, dry cleaning, washing and rubbing measured respectively. From the results of the dye absorption, the optimum dyeing condition of the wool and nylon fabrics with Chinese Scholar Tree extract is at 80C dyeing temperature for 60 minutes. The optimum concentration of mordanting agent is Al, Cr, Sn 1%, Fe, Cu 2% solution. In general, the fastness property of the dyed wool and nylon fabrics had a comparatively high grade.

• Conservation Science in Museum
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• v.9
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• pp.67-83
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• 2008

This study is process of conservation treatment for textiles and custumes containing Jikgeum(weave with supplementary golden wefts) and Bugeum(Gold sticking) among excavated ones(including all of Sinsu751) of Cheongyeongunju (a princess) collected by the National Museum of Korea. Adhesive strength was reinforced by coating 2% solution of glue on layer of gold disintegrated in the course of depletion of gold(Au) on the surface after conducting nondestructive test(X-ray fluorescent analysis) of flat gold strip and gold sticking. To remove dust on the surface and polluted materials, dry cleaning through vacuum suction and spray-type wet cleaning were conducted simultaneously and damaged part was restored to recover the relics to original state.