• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.7-8
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• 2010

The surface conductive layer (SCL) of chemical vapor deposition (CVD) diamonds has attracting much interest. However, neither photoemission electron microscopic (PEEM) nor micro-spectroscopic (PEEMS) information is available so far. Since SCL retains in an ultra-high vacuum (UHV) condition, PEEM or PEEMS study will give an insight of SCL, which is the subject of the present study. The sample was made on a Ib-type HTHP diamond (001) substrate by non-doping CVD growthin a DC-plasma deposition chamber. The SCL properties of the sample in air were; a few tens K/Sq. in sheet resistance, ${\sim}180\;cm^2/vs$ in Hall mobility, ${\sim}2{\times}10^{12}/cm^2$ in carrier concentration. The root-square-mean surface roughness (Rq) of the sample was ~0.2nm as checked by AFM. A $2{\times}1$ LEED pattern and a sheet resistance of several hundreds K/Sq. in UHV were checked in a UHV chamber with an in-situ resist-meter [1]. The sample was then installed in a commercial PEEM/S apparatus (Omicron FOCUS IS-PEEM) which was composed of electro-static-lens optics together with an electron energy-analyzer. The presence of SCL was regularly monitored by measuring resistance between two electrodes (colloidal graphite) pasted on the two ends of sample surface. Figure 1 shows two PEEM images of a same area of the sample; a) is excited with a Hg-lamp and b) with a Xe-lamp. The maximum photon energy of the Hg-lamp is ~4.9 eV which is smaller that the band gap energy ($E_G=5.5\;eV$) of diamond and the maximum photon energy of the Xe-lamp is ~6.2 eV which is larger than $E_G$. The image that appear with the Hg-lamp can be due to photo-excitation to unoccupied states of the hydrogen-terminated negative electron affinity (NEA) diamond surface [2]. Secondary electron energy distribution of the white background of Figs.1a) and b) indeed shows that the whole surface is NEA except a large black dot on the upper center. However, Figs.1a) and 1b) show several features that are qualitatively different from each other. Some of the differences are the followings: the two main dark lines A and B in Fig.1b) are not at all obvious and the white lines B and C in Fig.1b) appear to be dark lines in Fig.1a). A PEEMS analysis of secondary electron energy distribution showed that all of the features A-D have negative electron affinity with marginal differences among them. These differences can be attributed to differences in the details of energy band bending underneath the surface present in SCL [3].

• Analytical Science and Technology
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• v.24 no.4
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• pp.243-248
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• 2011

A selective determination method of mercury (II) ion in aqueous solution by luminol-based chemiluminescence system (luminol CL system) has been developed. Determination of metal ions such as copper (II), iron (III), chromium (III) ion in solution by the luminol CL system using its catalytic role in the reaction of luminol and hydrogen peroxide has been reported by several groups. In this study, the catalytic activity of mercury (II) ion in the reaction of luminol and hydrogen peroxide was observed by the enhanced CL intensity of the luminol CL system. Based on this phenomenon, experimental conditions of the luminol CL system were investigated and optimized to determine mercury (II) ion in aqueous solution. While mercury (II) ion in mixed sample solution containing mercury (I) and (II) ions highly enhanced the CL intensity of the luminol CL system, the mercury (I) ion could not enhanced the CL intensity. Thus selective determination of the mercury (II) ions in a mixture containing mercury (I) and (II) ions could be achieved. Each concentration of mercury (I) and (II) ions in aqueous solution can be obtained from the results of the CL method that give the concentration of only mercury (II) ion and the inductively coupled plasma (ICP) method that give the total concentration of mercury ions. On the optimized conditions, the calibration curve of mercury (II) ion was linear over the range from $1.25{\times}10^{-5}$ to $2.50{\times}10^{-3}M$ with correlation coefficient of 0.991. The detection limit of mercury (II) ion in aqueous solution was calculated to be $1.25{\times}10^{-7}M$.

• The Korean Journal of Mycology
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• v.44 no.1
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• pp.23-30
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• 2016

This study was conducted for comparison of ingredients, phytochemical compounds and antioxidant activity of Wofiporia extensa cultured in Gangwon-do, Gyeongsang-do, and Jeolla-do. Three contents of Wofiporia extensa were analyzed as oxygen (46~48%), carbon (38~39%), hydrogen (6.05~6.1%) and nitrogen (0.17~0.21%). The mineral contents of 50% ethanol Wofiporia extensa extracts were measured as sulfur (S) 145~149 ppm, Magnesium (Mg) 69~72 ppm, phosphorus (P) 122~154 ppm and calcium (Ca) 210.61~509.98 ppm. Wofiporia extensa from Gyeongsang-do (509.98 ppm) contained a significantly higher quantity of Ca than that from Gangwon-do (210.62 ppm) and Jeolla-do (223.88 ppm). In the gas chromatograph-mass spectrometry (GC-MS) analysis, oleic acid was identified in three 50% ethanol Wofiporia extensa extracts. In the 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2'-azino-bis-3-ethylbenzothiazoline-6-sulphonic acid (ABTS) assay for antioxidant activity, the $IC_{50}$ values of Wofiporia extensa cultured in Gangwon-do, Gyeongsang-do and Jeolla-do were calculated as 2.966 mg/mL, 23.03 mg/mL, and 4.16 mg/mL and 3.521 mg/mL, 12.17 mg/mL, and 7.40 mg/mL. In the ferric reducing antioxidant power (FRAP) assay, the $IC_{50}$ values of Wofiporia extensa cultured in Gangwon-do, Gyeongsang-do, Jeolla-do were 6.585 mg/mL, 19.06 mg/mL, and 18.97 mg/mL, respectively. In summary, Wofiporia extensa cultured in Gangwon-do had stronger antioxidant activity and higher concentration of oleic acid than that of Geyongsang-do and Jeolla-do. However, Wofiporia extensa cultured in Geyongsang-do contained a much higher concentration of Ca than that of Gangwon-do and Jeolla-do.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.107-108
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• 2008

The spectacular development of AMLCDs, been made possible by a-Si:H technology, still faces two major drawbacks due to the intrinsic structure of a-Si:H, namely a low mobility and most important a shift of the transfer characteristics of the TFTs when submitted to bias stress. This has lead to strong research in the crystallization of a-Si:H films by laser and furnace annealing to produce polycrystalline silicon TFTs. While these devices show improved mobility and stability, they suffer from uniformity over large areas and increased cost. In the last decade we have focused on microcrystalline silicon (${\mu}c$-Si:H) for bottom gate TFTs, which can hopefully meet all the requirements for mass production of large area AMOLED displays [1,2]. In this presentation we will focus on the transfer of a deposition process based on the use of $SiF_4$-Ar-$H_2$ mixtures from a small area research laboratory reactor into an industrial gen 1 AKT reactor. We will first discuss on the optimization of the process conditions leading to fully crystallized films without any amorphous incubation layer, suitable for bottom gate TFTS, as well as on the use of plasma diagnostics to increase the deposition rate up to 0.5 nm/s [3]. The use of silicon nanocrystals appears as an elegant way to circumvent the opposite requirements of a high deposition rate and a fully crystallized interface [4]. The optimized process conditions are transferred to large area substrates in an industrial environment, on which some process adjustment was required to reproduce the material properties achieved in the laboratory scale reactor. For optimized process conditions, the homogeneity of the optical and electronic properties of the ${\mu}c$-Si:H films deposited on $300{\times}400\;mm$ substrates was checked by a set of complementary techniques. Spectroscopic ellipsometry, Raman spectroscopy, dark conductivity, time resolved microwave conductivity and hydrogen evolution measurements allowed demonstrating an excellent homogeneity in the structure and transport properties of the films. On the basis of these results, optimized process conditions were applied to TFTs, for which both bottom gate and top gate structures were studied aiming to achieve characteristics suitable for driving AMOLED displays. Results on the homogeneity of the TFT characteristics over the large area substrates and stability will be presented, as well as their application as a backplane for an AMOLED display.

• The Korean Journal of Physiology
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• v.20 no.1
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• pp.53-63
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• 1986

Carbon monoxide(CO) poisoning has been one of the major environmental problems because of the tissue hypoxia, especially brain tissue hypoxia, due to the great affinity of CO with hemoglobin. Inhalation of the pure oxygen$(0_2)$ under the high atmospheric pressure has been considered as the best treatment of CO poisoning by the supply of $0_2$ to hypoxic tissues with dissolved from in plasma and also by the rapid elimination of CO from the carboxyhemoglobin(HbCO). Hydrogen peroxide $(H_2O_2)$ was rapidly decomposed to water and $0_2$ under the presence of catalase in the blood, but the intravenous administration of $H_2O_2$ is hazardous because of the formation of methemoglobin and air embolism. However, it was reported that the enema of $H_2O_2$ solution below 0.75% could be continuously supplied $0_2$ to hypoxic tissues without the hazards mentioned above. This study was performed to evaluate the effect of $H_2O_2$ enema on the elimination of CO from the HbCO in the recovery of the acute CO poisoning. Rabbits weighting about 2.0 kg were exposed to If CO gas mixture with room air for 30 minutes. After the acute CO poisoning, 30 rabbits were divided into three groups relating to the recovery period. The first group T·as exposed to the room air and the second group w·as inhalated with 100% $0_2$ under 1 atmospheric pressure. The third group was administered 10 ml of 0.5H $H_2O_2$ solution per kg weight by enema immediately after CO poisoning and exposed to the room air during the recovery period. The arterial blood was sampled before and after CO poisoning ana in 15, 30, 60 and 90 minutes of the recovery period. The blood pH, $Pco_2\;and\;Po_2$ were measured anaerobically with a Blood Gas Analyzer and the saturation percentage of HbCO was measured by the Spectrophotometric method. The effect of $H_2O_2$ enema on the recovery from the acute CO poisoning was observed and compared with the room air group and the 100% $0_2$ inhalation group. The results obtained from the experiment are as follows: The pH of arterial blood was significantly decreased after CO poisoning and until the first 15 minutes of the recovery period in all groups. Thereafter, it was slowly increased to the level of the before CO poisoning, but the recovery of pH of the $H_2O_2$ enema group was more delayed than that of the other groups during the recovery period. $Paco_2$ was significantly decreased after CO poisoning in all groups. Boring the recovery Period, $Paco_2$ of the room air group was completely recovered to the level of the before CO Poisoning, but that of the 100% $O_2$ inhalation group and the $H_2O_2$ enema group was not recovered until the 90 minutes of the recovery period. $Paco_2$ was slightly decreased after CO poisoning. During the recovery Period, it was markedly increased in the first 15 minutes and maintained the level above that before CO Poisoning in all groups. Furthermore $Paco_2$ of the $H_2O_2$ enema group was 102 to 107 mmHg and it was about 10 mmHg higher than that of the room air group during the recovery period. The saturation percentage of HbCO was increased up to the range of 54 to 72 percents after CO poisoning and in general it was generally diminished during the recovery period. However in the $H_2O_2$ enema group the diminution of the saturation percentage of HbCO was generally faster than that of the 100% $O_2$ inhalation group and the room air group, and its diminution in the 100% $O_2$ inhalation group was also slightly faster than that of the room air group at the relatively later time of the recovery period. In conclusion, the enema of 0.5% $H_2O_2$ solution is seems to facilitate the elimination of CO from the HbCO in the blood and increase $Paco_2$ simultaneously during the recovery period of the acute CO poisoning.

• Journal of Mushroom
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• v.16 no.2
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• pp.111-117
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• 2018

This study was conducted to compare the composition and antioxidant activity of 1- and 2-year-old Poria cocos Wolf cultivated at a mortuary and cemetery. An elemental analyzer test showed oxygen, carbon, hydrogen, nitrogen, and sulfur to be present at concentrations of 45~46%, 39~41%, 6.06~6.1%, 0.21~0.22%, and 0%, respectively. No differences in composition were observed among samples. Eleven minerals (S, Ca, Mg, P, As, Se, Cu, Fe, Pb, Zn, and Cd) found in P. cocos cultivated at the mortuary and cemetery were analyzed by inductively coupled plasma mass spectrometry (ICP). The levels of S, Fe, Mg, and Zn in P. cocos were higher in cemetery-cultivated samples than in mortuary-cultivated samples. A 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay for antioxidant activity revealed half-maximal inhibitory concentration ($IC_{50}$)values of P. cocos to be 8.601 mg/mL (mortuary, 1 year old), 12.85 mg/mL (cemetery, 1 year old), 1.23 mg/mL (mortuary, 2 years old), and 1.18 mg/mL (landfill, 1 year old). A 2,2'-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) assay revealed $IC_{50}$ values of 15.85 mg/mL (mortuary, 1 year old),14.59 mg/mL(cemetery, 1 year old), 3.9 mg/mL (mortuary, 2 years old), and 14.92 mg/mL (cemetery, 1 year old). The results showed a concentration-dependent effect. Two-year-old mortuary-cultivated P. cocos had the highest antioxidant activity among samples. Ultrastructure analysis with a field emission scanning electron microscope (FE-SEM) showed no obvious differences among samples.

• Journal of the Korean Society of Food Science and Nutrition
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• v.38 no.9
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• pp.1161-1166
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• 2009

The purpose of the present study was to effect of red pepper seeds powder on antioxidative defense system and oxidative damage in rats fed high fat high cholesterol diet. Rats were divided into five experimental groups which are composed of normal diet group, high fat high cholesterol diet group, high fat high cholesterol diet with 5% red pepper seeds powder supplemented group (SA group), high fat high cholesterol diet with 10% red pepper seeds powder supplemented group (SB group), and high fat.high cholesterol diet with 15% red pepper seeds powder supplemented group (SC group). Supplementation of red seed pepper groups (SA, SB, and SC groups) resulted in increased activities of hepatic glutathione peroxidase and superoxide dismutase. However, there was no significant difference in the activity of hepatic catalase among all experimental groups. Hepatic superoxide radical contents in microsome and mitochondria were significantly reduced in red pepper seeds powder supplemented groups. Hepatic hydrogen peroxide contents in mitochondria were significantly reduced 15% red pepper seeds powder supplemented group. Hepatic carbonyl values in microsome were significantly reduced in 10% and 15% red pepper seeds powder supplemented groups. Thiobarbituric acid reaction substance (TBARS) values in liver and plasma were reduced in red pepper seeds powder supplemented groups. These result suggest that red pepper seeds powder may reduce oxidative damage by the activation of antioxidative defense system in rats high fat.high cholesterol diets.

• Restorative Dentistry and Endodontics
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• v.34 no.2
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• pp.95-102
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• 2009

The aim of this study was to evaluate the influence of light energy on the tooth whitening effect of bleaching agent in vitro..Extracted human mandibular molars were sectioned to 2 fragments(mesial. distal) and lingual portions of crown were used in this study. All specimens were stained using a red wine for 24 hours and immersed in artificial saliva. Specimens divided into four groups, group 1 and 2 light-activated by LumaCool (LED, LumaLite, Inc., Spring Valley, USA), group 3 and 4 light-activated by FlipoWhite2 (Plasma acr lamp, Lokki. Australia). Group 1 and 3 bleached with Luma White (LumaLite, Inc., Spring Valley, USA), group 2 and 4 bleached with Polaoffice(SDI, Victoria, Australia). Bleaching treatment performed during 10 minutes every 24 hours and repeated 6 times. During bleaching treatment, distal fragments was light-activated (L) but mesial fragments was not(NL). Shade assessment employed before and after bleaching treatment using spectrophotometer. The results of the change in shade was compared and analysed between NL and L by using paired-sample T test with 95 % level of confidence. There were no significant differences between NL and L with a few exceptions. In group 2, $a^*$ value more change in L, in group 3, $b^*$ value more change in L, in group 4, $a^*$ value less change in L. After bleaching, $L^*$ value and ${\Delta}E$ increased in all groups and the value of $a^*$ and $b^*$ decreased in all groups. Within the limitation of this test conditions, the results of this study indicate that the light energy has no obvious improving impact on the tooth whitening effect of a bleaching agent.