• Proceedings of the Materials Research Society of Korea Conference
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• 한국재료학회 2011년도 춘계학술발표대회
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• pp.34.2-34.2
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• 2011

The demand for Ru has been increasing in the electronic, chemical and semiconductor industry. Chemical mechanical planarization (CMP) is one of the fabrication processes for electrode formation and barrier layer removal. The abrasive particles can be easily contaminated on the top surface during the CMP process. This can induce adverse effects on subsequent patterning and film deposition processes. In this study, a post Ru CMP cleaning solution was formulated by using sodium periodate as an etchant and citric acid to modify the zeta potential of alumina particles and Ru surfaces. Ru film (150 nm thickness) was deposited on tetraethylorthosilicate (TEOS) films by the atomic layer deposition method. Ru wafers were cut into $2.0{\times}2.0$ cm pieces for the surface analysis and used for estimating PRE. A laser zeta potential analyzer (LEZA-600, Otsuka Electronics Co., Japan) was used to obtain the zeta potentials of alumina particles and the Ru surface. A contact angle analyzer (Phoenix 300, SEO, Korea) was used to measure the contact angle of the Ru surface. The adhesion force between an alumina particle and Ru wafer surface was measured by an atomic force microscope (AFM, XE-100, Park Systems, Korea). In a solution with citric acid, the zeta potential of the alumina surface was changed to a negative value due to the adsorption of negative citrate ions. However, the hydrous Ru oxide, which has positive surface charge, could be formed on Ru surface in citric acid solution at pH 6 and 8. At pH 6 and 8, relatively low particle removal efficiency was observed in citric acid solution due to the attractive force between the Ru surface and particles. At pH 10, the lowest adhesion force and highest cleaning efficiency were measured due to the repulsive force between the contaminated alumina particle and the Ru surface. The highest PRE was achieved in citric acid solution with NaIO4 below 0.01 M at pH 10.

• Journal of Photoscience
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• 제1권2호
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• pp.135-141
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• 1994

Elevated near-UV radiation, containing a large amount of UV-B and a small amount of UV-C, inhibited the development of leaves and tillers, the increase in biomass production, the elongation of plant height, the photosynthetic rate and the chlorophyll content in rice plants in a phytotron. Elevated UV-B radiation filtered through cellulose diacetate film or UV-31 cut filter (transmission down to 290 nm) similarly suppressed each growth component above. Near-UV radiation-caused injuries were alleviated either by elevated CO$_2$ atmosphere or by exposure to high irradiance-visible radiation. On the basis of these findings, we examined cultivar differences in the resistance to UV radiation-caused injuries among 198 rice cultivars belonging to 5 Asian rice ecotypes ( aus, aman, boro, bulu and tjeleh) from the Bengal region and Indonesia and to Japanese lowland and upland rice groups. It was shown that .various cultivars having different sensitivities to the effects of near-UV radiation were involved in the same ecotype and the same group, and that the Japanese lowland rice group and the boro ecotype were more resistant. Among Japanese lowland rice cultivars, Sasanishiki (one of the leading varieties in Japan) exhibited more resistance to near-UV radiation, while Norin 1 showed less resistance, although these two cultivars are closely related. It was thus indicated that the resistance to the inhibitory effects of near-UV radiation of rice cultivars is not simply due to the difference in the geographical situation where rice cultivars are cultivated. From the genetic analysis of resistance to the inhibitory effects of UV radiation on growth of rice using F$_2$ plants generated by reciprocally crossing Sasanishiki and Norin 1 and F$_3$ lines generated by self-fertilizing F$_2$ plants, it was evident that the resistance to the inhibitory effects of elevated near-UV radiation in these rice plants was controlled by recessive polygenes.

• Restorative Dentistry and Endodontics
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• 제28권5호
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• pp.392-401
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• 2003

The purpose of this study was to evaluate the penetration pattern of dentin adhesives according to the orientation of dentinal tubules with confocal laser scanning microscopy. Specimens having perpendicular. parallel and oblique surface to dentinal tubules were fabricated. The primer of dentin adhesives (ALL $BOND^{\circledR}{\;}2,{\;}CLEARFIL^{TM}$ SE BOND and PQ1) was mixed with fluorescent material. rhodamine B isothio-cyanate (Aldrich Cherm. CO., Milw., USA), It was applied to the specimens according to the instructions of manufactures. The specimens were covered with composite resin (Estelite, shade A2) and then cut to a thickness of 500$\mu\textrm{m}$ with low speed saw (Isomet^{TM}, Buehler. USA). The adhesive pattern of dentin adhesives were observed by fluorescence image using confocal laser scanning microscopy. The results were as follows. 1. For the groups with tubules perpendicular to bonded surface. funnel shape of resin tag was observed in all specimen. However. resin tags were more prominent in phosphoric acid etching system (ALL $BOND^{\circledR}$ 2 and PQ1) than self etching system ($CLEARFIL^{TM}$ SE BOND). 2. For the groups with tubules parallel to bonded surface. rhodamine-labeled primer penetrated into peritubular dentin parallel to the orientation of dentinal tubules. But rhodamine-labeled primer of PQ1 diffused more radially into surrounding intertubular dentin than other dentin adhesive systems. 3. For the groups with tubules oblique to bonded surface. resin tags appeared irregular and discontinuous. But they penetrated deeper into dentinal tubules than other groups.

• Journal of Korean Society for Atmospheric Environment
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• 제17권5호
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• pp.425-437
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• 2001

This study is based on the uses meta-analysis methodology to examine the statistical consistency and importance of random variation among results of epidemiologic studies between air pollutants exposure and childhood asthma. Studies for this meta-analysis were conducted by reviewing previous results and by asking researcher active in this field for recommendations. Overall, 10 cases of air pollutants exposures and childhood asthma were reviewed. A variety of statistical methods for meta-analysis have been used to assess the combined effects, to identify heterogeneity, and to provide a single summary risk estimate based on a set of simiar epidemiologic studies. In this study, classification of exposure metircs on air environmental epidemiologic studies are reported for (1) aggravation of childhood asthma by a 50 ppb increase SO$_2$(6 individual studies); (2) aggravation of childhood asthma by a 50 ppb increase NO$_2$(5 individual studies); (3) aggravation of childhood asthma by a 50 ppb increase $O_3$(7 individual studies); (4) aggravation of childhood asthma by a 10$\mu\textrm{g}$/m$^3$increase PM$_{10}$ (4 individual studies); (5) aggravation of childhood asthma by a 1 ppm increase CO (2 individual studies); and (6) comparison of results between a Korean study results and this meta-analytic study. Results of this study indicated that an inverse-variance weighted pooling of the hospital admission risk at a 1ppm increment of CO levels was 1.12% (95% CI : 1.01 ~ 1.24). The hospital admission risk was estimated to increase 5% (95% CI : 1.02~1.08), 6%(95% CI : 1.04~1.09), and 5% (95% CI : 1.02~1.09) with each 50ppb increase of SO$_2$, NO$_2$, and $O_3$, respectively. In addition, our results lead to a small but significant elevation in risk of 2% (RR = 1.02, 95% CI = 1.01~1.04) with each 10$\mu\textrm{g}$/m$^3$increase of PM$_{10}$ among 4 individual studies. We found a small elevation in risk of childhood asthma, and pooled results of 10 epidemiologic studies of childhood asthma using increase a cut-off-point levels of air pollutants showed a few pieces of evidence. The results of this meta-analysis suggested that air pollution associated with an increased incidence of childhood asthma. According to this study, relationship between exposure to air pollutants and childhood asthma in Korea seem to be high than results of this meta-analysis.sis.

• The Journal of Korean Academy of Prosthodontics
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• 제49권1호
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• pp.8-15
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• 2011

Purpose: This study evaluated the bonding strength of direct relining resin to Co-Cr denture base material according to surface treatment and immersion time. Materials and methods: In this study, Co-Cr alloy was used in hexagon shape. Each specimen was cut in flat surface, and sandblasted with $110\;{\mu}m$ $Al_2O_3$ for 1 minute. 54 specimens were divided into 3 groups; group A-control group, group B-applied with surface primer A, group C-applied with surface primer B. Self curing direct resin was used for this study. Each group was subdivided into another 3 groups according to the immersion time. After the wetting storage, shear bond strength of the specimens were measured with universal testing machine. The data were analyzed using two-way analysis of variance and Tukey post hoc method. Results: In experiment of sandblasting specimens, surface roughness of the alloy was the highest after 1 minute sandblasting. In experiment of testing shear bond strength, bonding strength was lowered on group B, C, A. There were significant differences between 3 groups. According to period, Bonding strength was the highest on 0 week storage group, and the weakest on 2 week storage group. But there were no significant differences between 3 periods. According to group and period, bonding strength of all group were lowered according to immersion time but there were no significant differences on group B and group C, but there was significant difference according to immersion time on group A. Conclusion: It is useful to sandblast and adopt metal primers when relining Co-Cr metal base dentures in chair-side.

• Analytical Science and Technology
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• 제7권3호
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• pp.339-347
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• 1994

A multicolumn system consisted of two valve(10-port and 6-port valve)-three column (28% DC 200, SP 1700 and Chromosorb 102 column) was developed. Nine natural gas components composed of $N_2$, $CH_4$, $CO_2$, $C_2H_6$, $C_3H_8$, $i-C_4H_{10}$, $n-C_4H_{10}$, $i-C_5H_{12}$ 및 $n-C_5H_{12}$ completed all the baseline separation within 18 minutes. The accuracy and the precision of this system was tested. The retention times and the peak areas were determined with a repeatability between 0.02 and 0.16%, and less than 1%, respectively. Calibration curves for natural-gas components were plotted by the partial pressure injection method of pure gases, and good linear relationships for each component were presented. By using these calibration curves the accuracy of the multicolumn system compaired with that of the single column system for a certified standard gas of natural gas. As a result, relative error in the single and the multicolumn system was less than 0.5% and 0.04%, respectively. The result of application of this system in the analysis of importing LNG composition showed that the heating values calculated by the multicolum system were estimated lower compared with those calculated by the single column system and consequently, the importing price of LNG was able to be cut down.

• Membrane Journal
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• 제15권2호
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• pp.121-131
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• 2005

Separation and purification of lysozyme from chicken egg white was studied using ultrafiltration. We have obtained experimental data through the cellulose membranes with the molecular weight cut off (MWCO) of 10 kDa, 30 kDa and 100 kDa in a stirred ultrafiltration device. Certain amounts of egg white were dissolved into 20 mM phosphate buffers of pH 6, 7 and 8 to make protein solutions of $1\%,\;2\%,\;3\%\;and\;10\%$ concentration. Permeation flux increased with increasing MWCO of the membrane. Permeation flux increased with increasing transmembrane pressure (TMP) and decreasing the protein concentration. As the MWCO of membrane decreased, the selectivity increased. The selectivity increased with increasing TMP and protein concentration of the solution.

• Asian-Australasian Journal of Animal Sciences
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• 제29권12호
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• pp.1782-1789
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• 2016

This study evaluated the effect of vacuum and modified atmosphere (40% $CO_2+60%$ $N_2$, MA) packaging on the chemical composition, physicochemical properties and sensory attributes of chill-stored meat from 10 fallow deer (Dama dama) bucks at 17 to 18 months of age. The animals were hunter-harvested in the forests of north-eastern Poland. During carcass dressing (48 to 54 h post mortem), both musculus longissimus muscles were cut out. Each muscle was divided into seven sections which were allocated to three groups: 0, A, and B. Samples 0 were immediately subjected to laboratory analyses. Samples A were vacuum-packaged, and samples B were packaged in MA. Packaged samples were stored for 7, 14, and 21 days at $2^{\circ}C$. The results of the present study showed that the evaluated packaging systems had no significant effect on the quality of fallow deer meat during chilled storage. However, vacuum-packaged meat samples were characterised by greater drip loss. Vacuum and MA packaging contributed to preserving the desired physicochemical properties and sensory attributes of meat during 21 days of storage. Regardless of the packaging method used, undesirable changes in the colour, water-holding capacity and juiciness of meat, accompanied by tenderness improvement, were observed during chilled storage.

• Korean Journal of Food Science and Technology
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• 제9권3호
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• pp.220-224
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• 1977

To dry the sweet potato efficiently, the fresh sweet potato was soaked in hot water of $60{\sim}65^{\circ}C$ for $1{\sim}1.5hrs.$ and cut into 0.5cm thick slices, followed by pressing at $40kg/cm^2$. This predehydrated cake contained $43{\sim}55%$ moisture and can be dried further either by sundrying or hot air drying. Using the dried sweet potato, ethanol was produced (ethanol production; 433l/M/T) by the conventional alcohol fermentation. The extracts as a by-product ($340{\sim}450ml$ per Kg of fresh potato) contained 5% total sugar and may be used directly for alcohol fermentation without further concentration.

• Herbal Formula Science
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• 제7권1호
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• pp.167-181
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• 1999

Rhizoma Arisaematis, Lignum Akebiae, Rhizoma Zedoariae, Cortex Eucommiae, Folium Perillae, Radix Sophorae Subprostratae, Radixi, Radix Ledeboutriellae, Rhizoma Atractylodis, Herba Ephedrae, Radix Puerariae and Radi Aconitx Bupleuri have been used in Korea for many centuries as a treatment for various disease. The purpose of the present study is to determine the effect of several herbs on norepinephrine(NE) induced blood vessel contraction in rabbits and pigs. Rabbit(2 kg, male) were killed by $CO_2$ exposure and a segment (8-10mm) of each rabbit was cut into equal segments and mounted in a tissue bath. Contractile force was measured with force displacement transducers under 2-3 g loading tension. The dose of norepinephrine(NE) which evoked 50% of maximal response $(ED_{50})$ was obtained from cumulative dose response curves for NE $(10^{-6}{\sim}10^{-3}M)$. Contractions evoked by NE $(ED_{50})$ were inhibited significantly by Rhizoma Arisaematis, Lignum Akebiae, Rhizoma Zedoariae, Cortex Eucommiae, Folium Perillae, Radix Sophorae Subprostratae and Herba Ephedrae in abdominal aorta. Contractions evoked by NE $(ED_{50})$ were inhibited significantly be Lignum Akebiae, Rhizoma Zedoariae, Cortex Eucommiae, Herba Ephedrae, Radix Puerariae and Radix Bupleuri in femoral artery. Contractions evoked by NE $(ED_{50})$ were inhibited significantly by Radix Sophorae Subprostratae, Radix Aconiti and Herba Ephedrae in renal artery. These results indicate that each herb can relax NE induced contraction of rabbit and pig blood vessel selectively, and that this relaxation relates to Gui-Gyung(歸經).