• Journal of the Korea institute for structural maintenance and inspection
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• v.9 no.4
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• pp.177-186
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• 2005

The latest concrete structure has showed that the deterioration of durability has been increased by the damage from salt, carbonization, freezing & thawing and the others. Therefore, the measures for the concrete which has deteriorated durability have been taken. Among them, it has been often used that surface treatment which cuts off the deterioration factors of durability by protecting the surface of concrete. However, troubles such as fracture and rupture in the repair layer have been reported as time goes by due to the difference between the organic repair material like epoxy and concrete properties. Researchers have been developing the repair material which can cut off the deterioration factors of durability such as $CO_2$ gas, chloride ion and water by making the formation of concrete elaborate through the reaction with calcium ion when the surface improving agent is coated on the concrete. The main ingredient of that is inorganic substance which is the same as the concrete property. This study was evaluated the surface improving agent for permeability, watertightness, air-permeability, chemical resistance and elution resistance. As a result, it has been reported that the surface improving agent improves watertightness and air-permeability by penetration more than 10mm within concrete. Therefore, it is concluded that the surface improving agent developed in this research prevents deterioration of concrete durability when it is coated on the concrete structure.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.1 no.1
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• pp.130-147
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• 1990

This study intended to investigate the characteristics of adolescent drug user in Korea. A questionnaire on adolescent drug use was administered to 1st or 2nd grade 898 students (465 males, 433 females) from 9 senior high schools in Seoul area. The extent of current using six representative drugs such as cigarettes, alcohol, chemical substance inducing hallucination(e,g., thinner, bond etc.), psychostimulant, hypnotic and minor tranqulizer was self-reported. Also their psychological distress, self-concept and individual-related variables such as academic grade, deviant behavior, drug-using peers, the perceived availability of drugs, the degree of family discipline, and the perceived parents' attitude for drinking and smoking were surveyed. Subjects were grouped into six(male) or five(female) subgroups (nonuser, simple experiencer, one kind of drug user, two kinds of drugs user, three kinds of drugs user(male only), minor tranqulizer user) to their extent of drug use. Then ANOVA procedure performed for group comparison of their psychological distress, self-concept and individual-related variables. The results showed that the most popular drugs among adolescents in Korea were cigarettes and alcohol. Minor tranqulizer was used by about 2.8% of male and 7.41% of female subjects. In general abusers showed lower academic grade, more deviant experiences, having more drug-using peers, higher degree of psychological distress, and lower postitive self-concept than nonuser group. According to the results of discriminant analysis, hostility and deviant behavior were reliable predictive variables that distinguished abuser group from nonuser group among the associated variables in this study. These results suggest that some common factors affect drug use of Korean high school students : high school students who have many common risk factors could be abusers more easily. These findings supported risk factor theory that the extent of drug use of adolescents might be associated with general maladjustment in everyday life.

• Journal of the Korean Applied Science and Technology
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• v.34 no.1
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• pp.116-124
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• 2017

A plate-type inorganic pigment complex was manufactured in a manner that treats the surface of the complex by adjusting zeta potential between talc, an inorganic pigment used as a material for color cosmetics, and hydrophobic silica. Talc, which is usually used in the prescription of color cosmetics, is a plate-type, white-colored inorganic substance with good application and spreadability to skin. Furthermore, it features excellent dispersibility and extensibility as well as outstanding heat tolerance, light stability, and chemical resistance. In general, silica contributes to durable makeup and stabilized formulation. This paper covers a process of manufacturing an inorganic pigment complex, where hydrophobic silica was applied to the surface of talc by using differences in zeta potential after the surface charges of talc and hydrophobic silica had been adjusted with cationic and anionic surfactants, respectively. The resulting inorganic pigment complex was composed of talc whose surface is coated hydrophobic silica to the thickness of $1{\mu}m$ or less, which developed an effective hydrophobic property. Zeta potential was measured to analyze the surface charge of an inorganic pigment, and FT-IR, used to check the functional group of a surfactant, was applied to treat the surface of the pigment. The surface of the inorganic pigment complex was observed employing SEM, EDS, and FIB, while its structure was confirmed with XRD and FT-IR.

• Journal of Life Science
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• v.15 no.5 s.72
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• pp.796-801
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• 2005

For usage of natural antioxidants, sanjook (Sasa boreails var. chiisanensis) leaves were extracted with methanol and investigated about its antioxidative activities and stability. It showed that the antioxidant activity of methanol extracts from the leaves of sanjook depend on their concentration within range of 0.1 to 0.8 mg/ml. The methanol extracts from the leaves of sanjook represented $583{\mu}g/ml$ for $IC_{50}$ of DPPH radical scavenging ability, $800{\mu}g/ml$for $IC_{50}$ of SOD-like activity and $38{\mu}g/ml$for $IC_{50}$ of $H_{2} O_{2}$ scavenging ability, while BHT, as a compared substance, was $271{\mu}g/ml$ for $IC_{50}$ of DPPH radical scavenging ability, $680{\mu}g/ml$ for $IC_{50}$ of SOD-like activity and $30{\mu}g/ml$ for $IC_{50}$ of $H_{2} O_{2}$ scavenging ability, respectively. The anti-au-toxidation effect for methanol extracts from the leaves of sajook was $55\∼60\%$ within range of 0.1 to 0.8 mg/ml. The pH stability on methanol extracts from the leaves of sanjook was most stable at pH 6. The more acid or akali it became, the more unstable it turned. The thermostability on methanol extracts from the leaves of sanjook remained above $80\%$ of their DPPH activity at range of $0^{\circ}C{\;}to{\;}120^{\circ}$.

• Journal of Environmental Health Sciences
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• v.44 no.3
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• pp.283-292
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• 2018

Objectives: This study was conducted to identify hazardous factors that reflect the characteristics of the academy and to provide basic data of environmental safety standard. Methods: Heavy metals, volatile organic compounds, formaldehyde, pesticides and phthalates were measured in 20 academies, which were supplementary, music, art and physical education institutes. Results: In case of heavy metals, the 12 locations were detected for lead (Pb) over the standard value, and 15 locations were exceeded for the total heavy metal. In six locations, the concentrations of volatile organic compounds were exceeded the standard value of $400{\mu}g/m^3$, and two locations for formaldehyde were exceeded the standard value of $100{\mu}g/m^3$. The most commonly detected agents in the air dust were chlorpyrifos and diazinon. The concentrations of DEHP, DINP, and DBP were detected and exceeded in several academies, The risk assessment results showed that HCHO as carcinogen had a safety level of 10-7 to 10-6, and DEHP and DINP as non-carcinogens had a safety level as assessed to be under than 0.1. Conclusions: Through the investigation of long-term environmental and health effects related laws on academies, indoor air quality management might be needed because there were cases of exceeding standard.

• Korean Journal of Environmental Agriculture
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• v.18 no.2
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• pp.185-190
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• 1999

Autotoxic substance(s) from alfalfa(Medicago sativa L.) plants reduces germination and growth of adjacent new alfalfa after alfalfa. The autotoxic chemical(s) in alfalfa are clearly unknown. Our objective was to improve the sensitivity of an alfalfa seedling bioassay for evaluating autotoxic leaf extracts. We determined critical extract concentrations that inhibit seed germination and seedling growth, compared two different culture media, and evaluated the effects of extract sterilization on the sensitivity of the assay, by using streptomycin and autoclaving method. An agar medium in petri plate gave better responses of germination and seedling growth to the extracts than using filter paper in the plate. On agar medium, the concentration of extract required to reach 50% inhibition of root length was 2.7 g $kg^{-1}$, and of germination and hypocotyl length were 3.8 and 9.9 g $kg^{-1}$, respectively. Leaf extracts with 100 ppm streptomycin stimulated germination significantly compared to Leaf extract alone but reduced root length of control by 43%. Root length was more sensitive to the autotoxin(s) than was germination or hypocotyl length. These results suggest that agar medium mixed with extract and sterilization by autoclaving could be improved the consistency and precision of bioassay, and that root length was the best parameter of autotoxic effect of alfalfa leaf extract.

• Science of Emotion and Sensibility
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• v.16 no.3
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• pp.387-396
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• 2013

In this study, the influence of classroom smells (foot odor, hair smell, sour smell, and sweat smell) of male high school and sweat smell and the offensive odor substance (ammonia and butyric acid) on the electroencephalography (EEG) activities of 20 female volunteers, ranging in age from 30 to 50 were studied. The representative response of brainwave index by these smells stimuli was most pronounced on temporal lobes among the brain lobes. By comparison with background EEG activities on temporal lobes, the smells reduced the relative alpha band power (0.04~0.13) and increased the relative beta band power (0.02~0.06) and the relative gamma band power (0.03~0.09). The alpha wave was deactivated, high beta (18~30Hz) and gamma (30~50Hz) waves were remarkably activated. The order of EEG fluctuation caused by the smell stimulus is as follows; hair smell > butyric acid > foot odor, sour smell > ammonia > sweat smell. It means that the classroom smells cause an excessive brain arousal and straining and may be reducing one's attention and learning ability.

• Journal of Physiology & Pathology in Korean Medicine
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• v.27 no.1
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• pp.83-91
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• 2013

Pruritus is a unpleasant symptom in the skin that provokes the act of or desire to scratch. Mast cells are important effector cells in allergic reactions such as pruritus and inflammation. The purpose of this study was undertaken to investigate the synergic anti-pruritic and anti-inflammatory effects of Scutellariae Radix (SB) plus Flos Loncerae (FL) extracts in rat peritoneal mast cells (RPMCs), pruritogen-induced scratching mice and 2,4-dinitrofluorobenzene (DNFB)-induced allergic mice. We investigated the effect of SB, FL and SB plus FL extracts on the production of tumor necrosis factor (TNF)-${\alpha}$, interleukin (IL)-$1{\beta}$, and histamine in RPMCs, on the scratching behavior in ICR mice, and skin clinical serverity and inflammatory mediators in DNFB-induced allergic hairless mice. RPMCs stimulated with PMA plus A23187 or compound 48/80 significantly increased TNF-${\alpha}$, IL-$1{\beta}$ or histamine production compared with media control. However, TNF-${\alpha}$ IL-$1{\beta}$ or histamine levels increased by PMA plus A23187 or compound 48/80 treatment were significantly inhibited by SB, FL in a dose-dependent manner. Especially, SB plus FL pretreatment had a synergic inhibitory effects on stimulator-induced cytokines (TNF-${\alpha}$ and IL-$1{\beta}$) and histamine production. Moreover, SB plus FL administration had a synergic inhibitory effects on the scratching behavior induced by pruritogen (compound 48/80, histamine, serotonin, substance P) in ICR mice. Furthermore, SB plus FL administration had a synergic inhibitory effects on skin damage, inflammatory mediators, leukocyte and mast cell infiltration induced by DNFB in hairless mice. These results suggest that SB plus FL administration has a potential use as a medicinal plant for treatment against itching and inflammation-related skin disease.

• Journal of environmental and Sanitary engineering
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• v.5 no.2
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• pp.105-116
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• 1990

Seungbong Island is situated about 100km away Inchon Port in the western sea of the Korean Peninsula. Field investigations were conducted for two days each from June 30 through July 1, 1981 and from August 20 through 21, 1981. The results obtained are summarized as follows: Plants growing in this island consist of a total of 193 species (70 families, 151 genera, 170 species, 22 varieties and 1 forma). Pinus thunbergii was confirmed to be the dominant species. The natural degree observed in this island was high, as a whole. The coefficient of ferny plants (Pte-Q) is 0.95, lower than grass. Atractylodes japonica Koidz., Miscanthus sinensis Anders. var. purpurascense Rendle, and Rhododendron mucronulatum Turz. are distributed mainly on the forest bed of Pinus thunbergii. The poor distribution of Chenopodium album var. centrorubrum Makino, Setaria viridis (L.) Beauv., Amaranthus mangostanus Linne is considered attributable to the phenomenon of allellopathy caused by a chemical substance secreted from the leaves of Pinus thunbergii. The component ratio of species in this island is lower than that of other islands due probably to the small area of arable land and grassland. The poor growth of plants in the forest of Pinus thunbergii, the dominant species in this island, seems to be attributed to the low relative light intensity of the forest. Seaside plants consisting of a total of 7 species were distributed mainly in the vicinity of sandy beaches. Naturalized plants comprising a total of 11 species were relatively diversified in the number of species.

• Korean Journal of Environmental Agriculture
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• v.27 no.3
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• pp.231-238
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• 2008

This study proposed the method of phosphate recovery from municipal wastewater by using ferrous iron waste, generated from the mechanical process in the steel industry. In the analysis of XRD, ferrous iron waste was composed of $Fe_3O_4$ (magnetite), practically with $Fe^{2+}$ and $Fe^{3+}$. It had inverse spinel structure. In order to identify the adsorption characteristic of phosphate on ferrous iron waste, isotherm adsorption test was designed. Experimental results were well analyzed by Freundlich and Langmuir isotherm theories. Empirical constants of all isotherms applied increased with alkalinity in the samples, ranging from 1.2 to 235 $CaCO_3/L$. In the regeneration test, empirical constants of Langmuir isotherm, i.e., $q_{max}$ (maximum adsorption capacity) and b (energy of adsorption) decreased as the frequency of regeneration was increased. Experiment was further performed to evaluate the performance of the treatment scheme of chemical precipitation by ferrous iron waste followed by biological aerated filter (BAF). The overall removal efficiency in the system increased up to 80% and 90% for total phosphate (TP) and soluble phosphate (SP), respectively, and the corresponding effluent concentrations were detected below 2 mg/L and 1 mg/L for TP and SP, respectively. However, short-circuit problem was still unsolved operational consideration in this system. The practical concept applied in this study will give potential benefits in achieving environmentally sound wastewater treatment as well as environmentally compatible waste disposal in terms of closed substance cycle waste management.