• Journal of Sericultural and Entomological Science
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• v.53 no.1
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• pp.6-11
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• 2015

Antheraea yamamai silkworm cocoon is considered as a natural biocompatible materials, but can not be used as medical resources due to its difficult processability. In this study, we examined the general characteristics including cocoon shell weight and structural and thermal properties of Antheraea yamamai silkworm cocoon. The cocoon shell weight and thickness of wild silkworm cocoon was 0.528 g and 0.424 mm, respectively. The cocoon has yellow-green color in outside cocoon but white in inner layer cocoon. Amino acid analysis showed that the main amino acid of Antheraea yamamai cocoon is alanine, glycine, serine, aspartic acid, tyrosine and arginine. X-ray diffractometry showed that strong diffraction peaks at $2{\theta}=16.8^{\circ}$, $20.4^{\circ}$, corresponded to ${\beta}$-sheet structure and sharp diffraction peaks at $2{\theta}=15.0^{\circ}$, $24.3^{\circ}$, $30.0^{\circ}$ due to the presence of calcium oxalate on cocoon surface. Antheraea yamamai cocoon was degraded at $370^{\circ}C$. These results might be used as basic information for development of non-textile materials using Anthereae yamamai silkworm cocoon.

• Korean Journal of Soil Science and Fertilizer
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• v.50 no.4
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• pp.235-250
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• 2017

In this study, we monitored 4 volatile organic compounds (VOCs) such as chloroform, dichloromethane, 1,2-dichloroethane, and tetrachloromethane in groundwater samples to determine the detection frequency and their concentrations and evaluated the health risk level considering ingestion, inhalation, and skin contact. 75 groundwater wells were selected. 24 wells were from monitoring background groundwater quality level and 51 wells were from monitoring groundwater quality level in industrial or contamination source area. In the results, the detection frequency for chloroform, dichloromethane, 1,2-dichloroethane, and tetrachloromethane was 42.3%, 8.1%, 6.0%, and 3.4%, respectively. The average concentrations of VOCs were high in the order of chloroform ($1.7{\mu}g\;L^{-1}$), dichloromethane ($0.08{\mu}g\;L^{-1}$), tetrachloromethane ($0.05{\mu}g\;L^{-1}$), and 1,2-dichloroethane ($0.05{\mu}g\;L^{-1}$). Chloroform had the highest detection frequency and average detection concentration. In the contaminated groundwater, the detection frequency of VOCs was high in the order of chloroform, dichloromethane, 1,2-dchloroethane, and tetrachloromethane. The average concentrations for chloroform, dichloromethane, 1,2-dichloroethane, and tetrachloromethane were $2.23{\mu}g\;L^{-1}$, $0.08{\mu}g\;L^{-1}$, $0.07{\mu}g\;L^{-1}$, and $0.06{\mu}g\;L^{-1}$, respectively. All the 4 compounds were detected at industrial complex and storage tank area. The maximum concentration of chloroform, dichloromethane, and 1,2-dichloroethane was detected at industrial complex area. Especially, the maximum concentration of chloroform and dichloromethane was detected at a chemical factory area. In the uncontaminated groundwater, the detection frequency of VOCs was high in the order of chloroform, dichloromethane, and 1,2-dchloroethane and tetrachloromethane was not detected. The average concentrations for chloroform, dichloromethane, and 1,2-dichloroethane were $0.57{\mu}g\;L^{-1}$, $0.07{\mu}g\;L^{-1}$, and $0.03{\mu}g\;L^{-1}$, respectively. Although chloroform in the uncontaminated groundwater was detected the most, the concentration of chloroform was not exceeding water quality standards. By land use, the maximum detection frequency of 1,2-dichloroethane was found near a traffic area. For human risk assessment, the cancer risk for the 4 VOCs was $10^{-6}{\sim}10^{-9}$, while the non-cancer risk (HQ value) for the 4 VOCs is $10^{-2}{\sim}10^{-3}$.

• The Korean Journal of Soil Zoology
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• v.5 no.2
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• pp.125-131
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• 2000

Disposing technique for dairy cattle manure using earthworms and the possibility of utilizing earthworms in poultry feed were investigated. In addition, chemical properties of manure and cast of earthworms were investigated. Temperature in the vinyl-house for earthworm nursery was able to be maintained above 0$\^{C}$ in winter and 25-28$\^{C}$ in summer. In closed-covering method, the number of escaped earthworms was the highest among three covering methods. The time was longer after manure excretion, the numbers of escaped earthworm were higher. There were some incidences of mortality of earthworm in closed-covering site. The amount of manure ingested by earthworm was increased in order of non-covering, closed-covering and gap-covering method. Fresh manure was more ingested than old one by earthworm. Earthworms reduced manure about 50% on the dry weight base and reduced total amounts of N, P$_2$O$\_$5/ and K$_2$O of manure by 41, 50 and 60%, respectively. Earthworm could be utilized by adult poultry (>60 g) for feeding. However, adverse effect of live earthworm was observed with young poultry (<450 g).

• KOREAN JOURNAL OF CROP SCIENCE
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• v.37 no.3
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• pp.224-229
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• 1992

The objective of the study was to clarify the pattern of fertilizer absorption by tillering hybrid, IK$_1$/IRI. Nangano No.1 hybrid was included as non-tillering check hybrid. Hybrids were grown in pots and the plants were periodically analyzed for their chemical components like nitrogen, phosphorus, potassium, calcium and magnesium. The results obtained indicate that the amount of nitrogen, phosphorus and potassium absorbed by IK$_1$/IRI was slightly lower than that absorbed by Nangano No.1, except nitrogen in the maturity of IK$_1$ /IRI. However, no major differences were observed for the calcium and magnesium content between two hybrids. In most cases amount of nitrogen and calcium in the plant of two hybrids seemed to decrease as the plants mature, while amount of those chemicals in the ears increased. Nitrogen efficiency for IK$_1$ /IRI seemed a little lower than that for Nangano No.1.

• Journal of Korean Society of Environmental Engineers
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• v.38 no.10
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• pp.543-550
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• 2016

Amine-type PP-g-VBC-EDA adsorbent, which possesses anionic exchangeable function, was prepared through photoinduced graft polymerization of vinylbenzyl chloride (VBC) onto polypropylene non-woven fabric and subsequent amination reaction using ethylenediamine (EDA). Adsorption characteristics of anionic nutrients on the PP-g-VBC-EDA adsorbent have been studied by batch adsorption experiments. The equilibrium data well fitted the Langmuir isotherm model, and the maximum monolayer sorption capacity was found to be 59.9 mg/g for $NO_3-N$ and 111.4 mg/g for $PO_4-P$. The adsorption energies were higher than 8 kJ/mol indicating anion-exchange process as the primary adsorption mechanism. The pseudo-second order kinetic model described well the kinetic data and resulted in the activation energy of 9.8-36.7 kJ/mol suggesting that the overall rates of $NO_3-N$ and $PO_4-P$ adsorption are controlled by the chemical process. Thermodynamic parameters such as ${\Delta}G^o$, ${\Delta}H^o$ and ${\Delta}S^o$ indicated that the adsorption nature of PP-g-VBC-EDA for anionic nutrients is spontaneous and exothermic. The PP-g-VBC-EDA could be regenerated by washing with 0.1 N HCl.

• Journal of Conservation Science
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• v.32 no.3
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• pp.377-384
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• 2016

There are physical and chemical method for removement of a lacquered layer existing on the surface when gilding an iron Buddha, these caused environmental pollution by surface degradation and is very noxious for conservation scientist's health. Thus, on this study, we conducted a lacquered layer removement experiments using Nd:YAG Laser which is contactless and eco-friendly. Specimens were made by polishing $5{\times}5$ size of iron(99.9%) specimens surfaces evenly and by differing of number of coating of unrefined lacquer, so there were thickness differences of $10{\mu}m$, $20{\mu}m$, and $30{\mu}m$. The laser machine used in this study was Nd:YAG Laser, and we used two wavelength modes; 1064 nm(160~180 mJ) for infrared light region and 532 nm(50~350 mJ) for ultraviolet light region. The experiment done by investigating the transition of specimens' surfaces with laser wavelength, energy, and numbers of investigation. The remain amount of lacquered layer surfaces before/after laser irradiation was investigated by stereoscopic microscope, observation by SEM, Non-contact Surface Roughness Measurement Device, and FT-IR etc. As a result of each analysis, we could verify the thickness of $10{\mu}m$, $20{\mu}m$ of lacquered layer removed without surface degradation when using 1064 nm wavelength with $1.0J/cm^2$ density. We could find out that Nd:YAG Laser is effective for removing remained lacquered layers when gilding an iron Buddha. In the future, when not only the metal has made various studies also wood lacquered furniture or the like, it seems to be utilized to remove the lacquer without surface damage.

• Applied Biological Chemistry
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• v.46 no.2
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• pp.117-122
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• 2003

Starches from 4 rice cultivars, including Whachungchalbyeo and Whachungbyeo, together with two correspondiug conversion mutants with giant embryonic phenotype, Whachungchal-giant embryonic rice and Whachung-giant embryonic rice, were isolated to compare its physico-chemical properties. The amylose content and the length of glucose chains in the fractionated amylose was reduced in response to conversion of the rice cultivars for developing giant embryonic phenotype. For the fine structure of amylopectin, conversion to giant embyonic rice cultivars accompanied with slight increase in the length of B chain plus decrease in the amount of A chain, and also a slight increase in average glucose chains length of amylopectin fractions could be observed. X-ray diffractogram revealed 4 cultivars to be the representative A types. We could also obtain the results that the hydrolysis rate by glucoamylase in the waxy rice cultivars decreased in response to conversion to the giant embryonic rice cultivars, while the rate increased in the non-waxy rice cultivas. Termination temperature for gelatinization was observed to decrease in response to conversion into the giant embryonic rice cultivars, however, the enthalpy for gelatinization was found to increase with the same conversion process.

• Journal of Food Hygiene and Safety
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• v.32 no.1
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• pp.14-19
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• 2017

The purpose of the study was to simplify standard HACCP manual for improving the on-site applicability and increasing the implementation rate of HACCP program for small- and medium-sized dairy farms (SMDF). A survey was carried out in 32 SMDFs using a structured questionnaire. The results indicated that the number of workers had a positive correlation with HACCP certifications (p < 0.05). Most of HACCP non-certified farms (66.7%) were run by two workers with 40-60 cows and milking yields of 1,000-1,500 L per day. Major drawbacks for dairy farmers to implement current HACCP system were the difficulties in daily recording and facility management (40%). On the basis of the survey results, it was suggested that the development of on-site standard HACCP manual and user-friendly record chart with O/X checklist were the most urgent factors to increase HACCP implementation rate. In addition, the alternative third party service for microbial and chemical tests could also be accompanied for small-sized dairy farms.

• Applied Chemistry for Engineering
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• v.9 no.2
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• pp.226-231
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• 1998

Hot melt adhesive which is solventless type has been widely used due to the possibility of automated adhesion process. The main purpose of this study is the development of polyamide based hot melt adhesive to improve the property of conventional ethylene-vinyl acetate hot melt adhesive, which has an inherent problem against heat resistance. In this study, it was found that the terpolymers of nylon 6, nylon 66, and nylon 12(CM831, 843P types) instead of nylon homopolymer were suitable base resins for hot melt adhesive, since the disruption of regularity in the polymer chains reduced the crystallinity, resulting in lower melting point and melt viscosity. According to the results, the optimum adhesion property could be obtained by the using 75/25~50/50 weight radio of CM831/843P resin as a base resin. Terpene resin was used as tackifier to improve adhesion and wetting properties. The best result can be obtained with the 10 wt.% addition of terpene resin. The terpene resin acted as proper tackifier in this system which decreased the melt temperature and viscosity, but increased the mechanical strength of adhesive itself. Also, the rheological property of the adhesive changed from typical non-Newtonian behavior to Newtonian behavior as terpene resin was added.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.8
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• pp.176-182
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• 2018

One of the most important factor of esthetic prosthesis is the color of the teeth. Zirconia is produced in the process of design, milling, coloring, drying, and sintering. The effect of the drying degree of zirconia colorant on the color tone is examined. For the experiment, a total of 45 zirconia specimens(15 for each) were fabricated by using cad/cam system. The zirconia specimens(L block(LAZOR), Z block(Zircos-E block posterior), A block(AlphaZ)) were then subjected to zirconia sintering in accordance with the manufacturer's instructions, using a chemical coloring agent to Non-drying(0sec), intermediate (10sec), and completely dried (10min) temperature holding times. The color tone was measured using a spectrophotometer. The results were analyzed with a One-way analysis of variance and the Tukey post-hoc test (${\alpha}=.05$) The $L^*$ values of L, A specimens, $a^*$ values of A specimens, and $b^*$ values of Z specimens were not statistically different according to the degree of drying (p>0.05), While the $L^*$ value of Z specimen, $a^*$ value of L, Z specimen, $b^*$ values of L, A specimens were statistically different according to the degree of drying(p <0.05). In conclusion, the drying of zirconia colourants improves zirconia brightness and increases the optical properties of the enamel.