• Journal of Korean Ophthalmic Optics Society
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• v.17 no.2
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• pp.135-141
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• 2012

Purpose: Polymerization of HEMA(2-hydroxyethyl methacrylate) which can be used in the soft contact lens has been performed by using electron beam(EB) irradiation, and examined the best condition for the polymerization. Comparing the physical properties of the contact lenses to the one fabricated by thermal polymerization method, we check the use possibility of the EB irradiation to the fabrication of the soft contact lens. Methods: We investigated the degree of polymerization of the HEMA according to the composition of the monomer, the additive ratio and the dose of electron beam (0~120 kGy). The degree of polymerization was measured depending on the EB dose to research the best synthetic condition under the EB irradiation. The physical properties of the contact lens such as water content(%), oxygen transmissibility(Dk/t) and optical transmittance were analysed by using the FT-IR results with comparing the two different polymerization method (thermal and electron beam polymerization) with same additive ratio. Results: When the dose of electron beam was above 100 kGy, the degree of polymerization of HEMA was above 99% with regardless using cross-linker and initiator. The water content of the lens fabricated by EB method showed 10% higher than the one by the thermal method which was 40%. The lens fabricated by EB method also showed higher oxygen transmissibility(Dk/t) as same with the water content, and showed twice higher value in the lens fabricated by pure HEMA. According to the FT-IR results, hydrophilic property of the lens fabricated by EB method was increased due to increasing the intermolecular hydrogen bonding. It showed above 90% optical transmittance in the visible range of wavelength on the contact lenses fabricated by the both of two different polymerization method. Conclusions: The polymerization of HEMA without cross-linker and initiator was successful above 100 kGy of EB irradiation. Moreover the lens fabricated from the polymer synthesized by pure HEMA with 100 kGy of EB showed the highest water content and oxygen transmissibility. Therefore EB irradiation is another possible method to synthesize the polymer which can be used for the soft contact lens.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.4
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• pp.414-419
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• 2005

This study was performed to compare the treatment efficiencies of two media, newly developed Bio-rock and conventional gravel, in soil clothing contact oxidation process. The composition of synthetic wastewater were $COD_{Cr}$ $150{\sim}370\;mg/L$, $BOD_5$ $150{\sim}270\;mg/L$, T-N $20{\sim}60\;mg/L$, T-P $5{\sim}25\;mg/L$, pH 7 and 2 mL/L of trace element solution. The experiment using two reactors was comparatively conducted for the flow rate of 40 L/d for 13 months, respectively. Initially Bio-rock reactor was increased to pH 12 due to $Ca(OH)_2$ with hydration of cement, but gravel reactor was dropped to pH 4 due to the degradation of organic material and nitrification. This significant pH variation deteriorated the growth and activity of microorganism. But the high pH of Bio-rock seems favorite to ammonia stripping and precipitation of phosphate. Such pH variation of Bio-rock and gravel reactors were finally stabilized to pH 8 and pH 6, respectively. The removal efficiencies of organic compounds from Bio-rock reactor were 96% of $COD_{Cr}$, 98% of $BOD_5$, 80% of T-N and 85% of T-P which stably coping against variation of influent concentration. But those of gravel reactor were 96% of $COD_{Cr}$, 96% of $BOD_5$, 42% of T-N and 40% of T-P, respectively. The Bio-rock was 2 times higher than T-N and T-P in treatment efficiency. And electron-microscopic examination showed that Bio-rock was more favorable to microbial adherence than gravel. The microbial populations were $5.2{\times}10^6\;CFU/mL$ of Bio-rock reactor compared to $2.6{\times}10^6\;CFU/mL$ in gravel reactor. In result Bio-rock was favor to microbial adherence and high treatment efficiency in spite of variation of influent concentration which had the advantages in saving running time and reducing site requirement.

• The Korean Journal of Pharmacology
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• v.22 no.1 s.38
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• pp.34-44
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• 1986

In our previous studies, we had clarified many pharmacological effects of majarine: the bacteriostatic effect in vitro; the potentiation of hypnotic action of alcohol; hypotensive effect in rats and hypothermic effect in mice. This study was undertaken to search for a new antihypertensive drug. Red crystalline was obtained from majarine (which was extracted from Berberis koreana Palibin) by chemical methods. And this crystalline was identified as $C_{19}H＿{16}NO＿4$ contained one hydroxy group instead of methoxy group of majarine in isoquinoline ring and named 'Majarol' (5,6-Dihydro-9-hydroxy, 10-methoxybenzo-[g]-1,3-benzodioxolo [5,6-a] quinolizinium). We examined the effects of majarol on blood pressure and heart rate in urethane ancsthetized rats and the rate and amplitude of contraction of isolated frog heart. Several drugs: atropine sulfate, diphenhydramine chloride, hexamethonium bromide, phentolamine, epinephrine, propranolol and isoproterenol were used to clarify the mechanism of the hypotensive action of majarol. The results of experimints were as follows; 1. In low dose (0.5-2mg/kg, i.v.), majarol showed a typical transient hypotensive effect and slight decrease in heart rate. In high dose (5-10 mg/kg, i.v.), majarol showed a typical transient and a subsequent prolonged hypotensive effect and a significant prolonged decrease in heart rate was followed. 2. The hypotensive effects of majarol was not abolished by the pretreatments with atropine sulfate, hexamethonium bromide and diphenhydramine. The pretreatment with phentolamine inhibited significantly the hypotensive effects of majarol and the pretreatment wtih majarol blocked markedly the hypertensive effect of epinephrine. The positive chronotropic effect of isoproterenol was not blocked by the pretreatment with majarol. 3. In low dose, majarol increased the amplitude and decreased rate of contraction, but in high dose, majarol inhibited the amplitude and rate of contraction of isolated frog heart.

• The Korean Journal of Pesticide Science
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• v.3 no.3
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• pp.11-19
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• 1999

A some of synthesized 2-(4-(6-chloro-2-benzoxazolyloxy)phenoxy)-N-phenyl propionamide derivativesa substrates were found to selectivity significantly with both rice plant (Oryza sativa L.) and barnyard grass (Echinochloa crus-galli) for those her- bicidal activities with post emergence in up land. The selectivity of substrates against rice plant better than that of Fenoxaprop-ethyl. The structure activity relationship (SAR) n the selectivity of N-phenyl substituents were analyzed by the Free-Wilson and Hansch method. The SAR approach against barnyard grass is shown that the optimal ($({\pi})_{opt.}=1.60$) hydrophobicity and electron donating effects ($0<{\sigma}$ & 0$(ES)_{opt.}=0.87$) so that the herbicidal activity against rice plant can be decreased. The significance of these results on the selectivity between barnyard grass and rice plant is discussed. And it is assumed that the 2-ethoxy-3-methoxy-4-dimethylamino group substituent ($pI_{50}$=6.60, 1g/ha) is selected as the most highest herbicidal activity against barngard grass in green house.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.10
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• pp.1058-1064
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• 2005

This research was designed to investigate the removal of anionic species, such as $F^-$, $Cl^-$ and ${NO_3}^-$, by adsorption on the clay minerals. Bentonite, $Ca^{2+}$ or $Na^+$ ion exchanged bentonite and montmorillonite, such as KSF and K10 from Sigma Aldrich, were used as the adsorbent. The component of five inorganic adsorbent was analyzed by XRF and XRD and the concentration of anion was measured by ion chromatography. From the experimental results, it was shown that the adsorption equilibrium was attained after 8-24 hours. For the amount of 6 g of each adsorbent, the adsorption capacities of $F^-$ and ${NO_3}^-$ on KSF was the largest as $825\;{\mu}g/g$ and $707\;{\mu}g/g$ respectively and that of $F^-$ on $Ca^{2+}$ ion exchanged bentonite was $255\;{\mu}g/g$ and that of ${NO_3}^-$ on K10 was $103\;{\mu}g/g$. In general, the efficiency of removal for the anionic species was increased with increasing of the amount of the adsorbent. Especially, for the amount of 6 g of KSF, the efficiency of removal for $F^-$ and ${NO_3}^-$ was 99% and 95% respectively. But, for all adsorbents, the efficiency of removal for $Cl^-$ was less than 9%. Also, a Freundlich equation was used to fit the acquired experimental data. As the result, for the $F^-$ and ${NO_3}^-$ on KSF, Freundlich constants, K, was respectively 1.09 and $0.45\;[mg/g][L/mg]^{1/n}$ and the adsorption intensity(1/n) was determined to be 0.08 and 0.27 respectively.

• The Korean Journal of Pesticide Science
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• v.14 no.3
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• pp.226-234
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• 2010

Foliage residue toxicity experiment was performed against honeybee (Apis mellifera) with bifenthrin, a synthetic pyrethroid insecticide with strong acute contact toxicity and imidacloprid, a neo-nicotinoid insecticide with strong acute oral toxicity to know the honeybee toxicity at the residue level on the leaves of alfalfa and apple. Also, the formulation differences to honeybee toxicity were investigated with WP (2%) and EC (1%) of bifenthrin and WP (10%) and SL (4%) of imidacloprid. Generally, foliage residual toxicity of honeybee and residual amounts of tested insecticides was higher in alfalfa leaves with large leaf area per unit weight than in apple leaves. While on the other hand, the only bifenthrin WP treatment showed higher honeybee toxicity on apple leaves than alfalfa. Although imidacloprid showed higher residue amounts ranged $4.9{\sim}25.4\;mg{\cdot}kg^{-1}$ than bifenthrin ranged $0.6{\sim}12.7\;mg{\cdot}kg^{-1}$ on the leaves, the residual toxicity to honeybee was lower than bifenthrin because of its strong penetration character. In conclusion, the residual toxicity of insecticide to honeybee could be affected by the contact and vaporized toxicity of chemical, the residual amounts on the surface of leaves, and the leaf area per unit weight and formulation differences.

• Clean Technology
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• v.11 no.3
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• pp.123-128
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• 2005

Among various metal oxides semiconductors, $TiO_2$ is the most studied semiconductor for environmental clean-up applications due to its unique ability in photocatalyzing various organic contaminants, its chemical inertness, and nontoxicity. $TiO_2$, however, has a few drawbacks to be solved such as reactivity mainly working under ultraviolet irradiation (${\lambda}$ < 387 nm) and electron - hole recombination on $TiO_2$. In this study, to extend the absorption range of $TiO_2$ into the visible range and enhance electron - hole separation, we synthesized platinum (Pt) deposited $C-TiO_2$. The presence of Pt as an electron sink has been known to snhance the separation of photogenerated electron-hole pairs and induce the thermal decomposition. The characterization of as-synthesized $Pt-C-TiO_2$ was performed by Transmission Electron Microscopic (TEM), the Brunuer-Emmett-Teller (BET) method, X-ray Diffractometer (XRD), UV-vis spectrometer (UV-DRS), and X-ray Photoelectron Spectroscopy (XPS). In order to estimate the photocatalytic activity of the synthesized materials, the photoelectron Spectroscopy (XPS). In order to estimate the photocatalytic activity of the synthesized materials, the photodegradation experiment of an azo dye (Acid Red 44; $C_{10}H_7N=NC_{10}H_3(SO_3Na)_2OH$)was carried out by using an Xe arc lamp (300 W, Oriel). A 420 nm cut-off filter was used for visible light irradiation. From the results, Pt-deposited $C-TiO_2$ showed a far superior phothdegradation activity to Degussa P25, the commercial product under the irradiation of visible light and enhanced photocatalytic activity of visible-working $C-TiO_2$. This is a useful result into the application for the purification system of dye wastewater using visible energy of sun light.

• The Journal of the Petrological Society of Korea
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• v.6 no.3
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• pp.210-225
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• 1997

From their general natures of peraluminous, S-type and ilmenite-series granites, two-mica granites in the Cheongsan, Inje-Hongcheon, Yeongju and Namwon areas were originated from crust-derived granitic magma and solidified under reducing condition. Each two-mica granite in Inje-Hongcheon and Namwon districts was differentiated from the the residual magma of porphyric biotite granite and high Ti/Mg biotite granite, respectively. The genetic relationships between two-mica granite and porphyritic biotite granite in Chenongsan district and between two-mica granite and biotite granodiorite in Yeongju district are ambiguous. In Namwon district granitic magmas were water-saturated and possible water solubilities in magmas were more than 5.8wt.%. In Yeongju district two-mica granitic magma was nearly water-saturated and showed possible water solubilities between 2.4~5.8wt.%. Two-mica granitic magmas in Cheongsan and Inje-Hongcheon districts were water-undersaturated. Pressure-dependent minimum melt compositions (0.5~2kb) and petrographic textures of two-mica granites in Inje-Hongcheon and Yeongju districts represent that the granites intruded and solidified at shallow level, whereas those in Cheongsan and Namwon districts exhibit relatively deeper level of granitic intrusion (2-3kb). The intersection of granite-solidus/muscovite stability indicates that magmatic primary muscovite can be crystallized from the water-saturated magma above 1.6kb (ca. 6km), but below the pressure muscovite can be formed by the subsolidus reaction. On the other hand, more pressure would be necessary for the crystallization of primary muscovite from the water-undersaturated magma. This pressure condition can explain the occurrence of primary and secondary muscovites from the two-mica granites in the areas considered. The experimental muscovite stability must be cautious of the application to examine the origin of muscovite. The muscovite stability can move toward high temperature field with adding of Ti, Fe and Mg components to the octahedral site of pure muscovite end member.

• Journal of Food Hygiene and Safety
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• v.17 no.1
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• pp.1-7
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• 2002

This study was performed to investigate the possibility of water purification by a wild train of Oenanthe javanica DC. Three commercially available dishwashing detergents and a standard surfactant, linear alkylbenzene sulfonate (LAS), were used for this study. The experiment was done in 1.5 ι transluscent aquariums. The plants were distributed into various concentrations of detergents and various kinds of detergent in the separate aquariums. The wet weight of the plants was significantly decreased (p<0.05), and the visual vitality of the plants also decreased in 2 days. The higher the concentration of detergent was, and the more time the plants were exposed to the detergents, the more decrease of growth was observed. The pH value of the culture media decreased in 2 days and in 4 days, then slightly increased in 6 days. However, the pH value of the media did not return to the initial neutral level of pH in 6 days. The pH value of the culture media containing the LAS remarkably increased in 6 days and increased to a neutral pH value in 18 days (p<0.01) as the pH of the other culture media. The chemical oxygen demand (COD) of the culture media gradually increased over the 4 days. A decrease of COD was observed in 6 days, but no tendency was observed between 12 and 18 days. The detergent in the culture media was highly significantly decreased in 2 days (p<0.01) and gradually decreased after this. After 6 days the remaining detergent was 12.4∼23.7% from the various levels of initially added concentration, and 22.4 ∼34.2% from the flour kinds of detergents. These results show that the reduction of detergent was caused by Oenanthe javanica and the effect was significant during the first 6 days when the plants were still growing well. These results indicate that the plant purifies contaminated water for several days and the effect could be variable according to the level of contamination and the environment in which the plant grows.

• The Journal of Korean Academy of Prosthodontics
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• v.46 no.5
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• pp.511-519
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• 2008

Statement of problem: An incompatibility between the initiator systems of self-curing composite resins and light-curing adhesives was supposed recently. Purpose: The purpose of the study was to evaluate the influence of activators for self/dual bonding on dentin shear bonding strengths. Material and methods: Fifty human molars were divided into 5 groups. A flat dentin surface was created for each tooth. A self-curing composite resin (Luxacore) was bonded with the following adhesives (n = 10); One-Step, Prime&Bond NT, AdheSE, Prime&Bond NT and AdheSE were also used in combination with activators. Shear bond strengths were measured after 24 hours of water storage. The specimens were loaded in shear in the Instron until failure at a 1 mm/min crosshead speed. Data were compared using one-way ANOVA and Tukey HSD test (${\alpha}$= 0.05). Results: The dentin adhesive systems in order of decreasing median bond strength were One-Step > Prime&Bond NT with activator, AdheSE with activator > Prime&Bond NT, AdheSE. Among adhesives, One-Step had the highest bond strength. Prime&Bond NT with activator had higher bond strengths than Prime&Bond NT that was used alone, and so was AdheSE. Conclusion: Shear bond strengths were increased in Prime&Bond NT and AdheSE when these were used with activators comparing used without activators. But using activators was not effective clinically comparing One-Step.