• Korean Journal of Soil Science and Fertilizer
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• v.16 no.2
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• pp.168-178
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• 1983

Influence of several dehydration treatments on original structure and water behavior in the process of drying were investigated employing three hawaiian volcanic ash soils and four synthetic minerals. These three soils were developed under different rainfall condition and contained three different amount of amorphous materials in them. Measurement of water losses by oven drying at $105^{\circ}C$, $P_2O_5$ drying, freeze drying, and critical point drying revealed that more water losses were noted by oven drying than by three other drying techniques and the differences of water losses between oven and $P_2O_5$-drying were closely related to amoun: of amorphous materials in them, showing the order of Kaiwiki > Hilo > Kawaihae. This indicates that dehydration of amorphous materials by elevated temperature ($105^{\circ}C$) excluded water beyond that in the adsorbed (hygroscopic) state. The effect of dehydration treatments on initial structure was visualized by scanning electron microscopy. The micrographs showed that oven-and $P_2O_5$-dried samples formed into large mass of sub-angular blocky, dense, and closed crumbs, while the freeze dried and critical point dried samples resulted in less shrinkage, and small, fluffy and open spongy structure. However, critical point drying technique produced bulkier, softer, and greater open structure samples than even freeze drying. Additional Index Words: original structure, synthetic minerals, critical point drying, $P_2O_5$ drying. 1. This is a part of author's Ph.D. dissertation submitted to the University of Hawaii, Honolulu, Hawaii 96822 in 1979. 2. Professor of Agricultural Chemistry, Korea University.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.21 no.3
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• pp.156-161
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• 2011

Objectives: Tetrahydrofuran (THF) is a colorless, water-miscible organic liquid with low viscosity at standard temperature and pressure. THF has been used as a solvent and a precursor for various syntheses of polymers. However, THF is known to irritate to the eyes, skin and mucus membranes. Overexposure by inhalation, ingestion or skin contact may produce nausea, dizziness, headaches, respiratory irritation and possible skin burns. The purpose of this study is to evaluate of the worker exposure and characteristics of workers in the workplaces that use or manufacture THF. Methods: Sixteen factories in Korea, which manufacture or use THF, were selected for this study and a total of 130 air samples including 104 time-weighted average (TWA) samples and 26 short-term exposure limit (STEL) samples, were collected. Air samples were collected with charcoal tube (100mg/50mg) and analyzed by gas chromatograph/flame ionization detector(GC/FID). Results: The TWA concentration of THF was 16.05ppm (GM) at PS script printing, 2.32ppm (GM) at PVC stabilizer, 1.03ppm (GM) at Lithium triethylborohydride, 0.63ppm (GM) at Polytetramethylene ether glycol(PTMEG), 0.42ppm (GM) at Manufacturing THF, 0.13ppm (GM) at Glue and 0.12ppm (GM) at synthetic rubber/resins. Two out of sampes for PS script printing exceeded 50ppm as 8-hour exposure limit of MOEL. The short term exposure to THF was 54.77ppm (GM) at PS script printing, 17.10ppm (GM) at PTMEG, 13.76ppm (GM) at Manufacturing THF, 2.86ppm (GM) at Lithium triethylborohydride, 0.87ppm (GM) at synthetic rubber/resins and 0.13ppm (GM) Glue. We found that the highest exposure process for both the TWA and STEL samples was PS script process. Two samples exceeded 100ppm as short term exposure limit of Ministry of Employment and Labor(MOEL). Conclusions: Characteristic of STEL concentration for THF is considerably different from TWA concentration in workplaces because workers could exposure high concentration of THF in a moment when they work irregularly schedule. So exposure controls for momentary works have to be prepared, and considered the skin absorption and inhale of THF.

• The Korean Journal of Mycology
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• v.27 no.2 s.89
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• pp.94-99
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• 1999

For the purpose of utilizing cellulose resources by cellulolytic enzymes of Stropharia rugosoannulata, it's cultural conditions for the prodution of cellulolytic enzymes in synthetic media were investigated. The optimum pH for the production of Avicelase and ${\beta}-glucosidase$ was pH 5.0, while that of CMCase was pH 4.0. The optimum temperature for the production of Avicelase, CMCase and ${\beta}-glucosidase$ was $40^{\circ}C$. Among the carbon sources, xylose was good for the production of CMCase and ${\beta}-glucosidase$, but maltose was good for the production of Avicelase. The optimum concentration of the carbon sources for the production of CMCase, Avicelase and ${\beta}-glucosidase$ was 1.0, 0.8 and 1.1%, respectively. As inorganic nitrogen sources, $NH_4Cl$ was good for the production of all the three cellulolytic enzymes. The optimum concentration of $NH_4Cl$ for the production of CMCase was 0.3% while that of Avicelase and ${\beta}-glucosidase$ was 0.4%. As organic nitrogen sources, malt extract was good for the production of all the three cellulolytic enzymes. The optimum concentration of organic nitrogen for the production of ${\beta}-glucosidase$ was 1.3% while that of CMCase and Avicelase was 1.0%. As the mineral sources, $CoCl_2$ good for the was good for the production of all the three cellulolytic enzymes. The optimum concentration of $CoCl_2$ for the production of all the three enzymes was 0.35%.

• The Korean Journal of Mycology
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• v.14 no.2
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• pp.131-139
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• 1986

Cultural and nutritional conditions for Lyophyllum decastes and its chemical composition in a synthetic medium were investigated. The optimal temperature and pH for the production of mycelium were $25^{\circ}C$ and pH 7.5. The mycelium yield was the highest on 15th day. Among the carbon sources, glucose and CMC were the best for the production of mycelium and their optimal concentrations were 3 and 6%, respectively. As an organic nitrogen, proteose peptone was the best and $(NH_4)_2HPO_4$ as an inorganic nitrogen was good. The optimal concentration of proteose peptone and $(NH_4)_2HPO_4$ were 2 and 0.2%, respectively. The optimal ratio of glucose to proteose peptone for production of mycelium was 10 : 1. Also, the optimal concentrations of $K_2HPO_4$ and $MgSO_4$ were 0.2 and 0.06%, respectively and that of $CaCl_2$ was 0.1%. Among the bioextracts, yeast extract was the most effective and its optimal concentration was 1.5%. In chemical components of the mycelium of Lyophyllum decastes, total sugar, crude protein and crude fat were 34.80, 28.35 and 2.50%, respectively. Its ash was 7.57% and crude fiber 11.99%.

• Journal of Conservation Science
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• v.35 no.6
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• pp.681-688
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• 2019

In this study, the characteristics of natural and synthetic adhesives used in woodcraft were evaluated. The pattern of deterioration of wood and adhesives according to changes in temperature and humidity were compared. For materials, one type of anlmal glue, three kinds of polyvinyl acetate adhesives, one type of epoxy adhesive and one type of zelkova wood were selected. Characteristics of physical and chemical characteristics, weather resistance and drying speed assessment were carried out. The adhesion characteristic evaluation showed that the adhesion strength of anlmal glue and one type of polyvinyl acetate adhesive were 6.54 N/㎟ and 7.01 N/㎟, pH meter of anlmal glue and polyvinyl acetate adhesives was pH 7.03 and pH 3.32-3.59 which were range of available as an adhesive. According to the test results of weather resistance, epoxy adhesives had the highest decreasing value in adhesion strength after deterioration. In the reversible test of the adhesive, it was found to be highly reversible in NaOH, a soluble solvent excluding epoxy, but attention is required when using the wood since it may show discoloration during processing.

• KSBB Journal
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• v.22 no.5
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• pp.271-277
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• 2007

Natural pigments have many applications like colouring agent, pigments, food additives, and antiseptics. At present, instead of synthetic pigments that have contributed to the development of industry, many kinds of natural pigments have been developed. The constituents of gardenia fruits, Gardenia jasminoides ELLIS, are traditionally known as herb medicine and natural dyes/pigments due to the customer is needs. The fruits produce yellow carotenoid pigments and iridoid compounds. The two main components in the yellow pigments are called crocin and crocetin. The extraction mode of yellow pigment from Gardenia is depended upon the extraction time, temperature, and volume of solvent. Red pigments or blue pigments formed from geniposide and amino acids have been reported a lot. Geniposide, the principal iridoid glucoside contained in gardenia fruit, was hydrolyzed to genipinic acid or genipin as a precursor for the pigment by enzymatic or chemical reaction. These red or blue pigments prepared with materials hydrolyzed of geniposide and amino acid and had properties governed by the electrostatic character of the amino acid. The pigments showed good stability to heat and pH but were gradually bleached by light while the other natural pigments are unstable in light, heat, acid, and base solution. The safety of the pigments was considered to be of little virulences in comparison to synthetic pigments.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.35 no.1
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• pp.38-50
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• 2013

Purpose: The aim of this study is to evaluate the effect and potential of electron beam (E-beam) irradiation treatment to the synthetic bony mixtures composed of hydroxyapatite (HA; Bongros$^{(R)}$, Bio@ Co., Korea) and tricalcium phosphate (${\beta}$-TCP, Sigma-Aldrich Co., USA), mixed at various ratios and of type I collagen (Rat tail, BD Biosciences Co., Sweden) as an organic matrix. Methods: We used 1.0~2.0 MeV linear accelerator and 2.0 MeV superconductive linear accelerator (power 100 KW, pressure 115 kPa, temperature $-30{\sim}120^{\circ}C$, sensor sensitivity 0.1~1.2 mV/kPa, generating power sensitivity 44.75 mV/kPa, supply voltage $5{\pm}0.25$ V) with different irradiation dose, such as 1, 30 and 60 kGy. Structural changes in this synthetic bone material were studied in vitro, by scanning electron microscopy (SEM), elementary analysis and field emission scanning electron microscope (FE-SEM), attenuated total reflection (ATR), and electron spectroscopy for chemical analysis (ESCA). Results: The large particular size of HA was changed after E-beam irradiation, to which small particle of TCP was engaged with organic collagen components in SEM findings. Conclusion: The important new in vitro data to be applicable as the substitutes of artificial bone materials in dental and medical fields will be able to be summarized.

• Asian Journal of Turfgrass Science
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• v.25 no.2
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• pp.202-207
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• 2011

Organic fertilizers are divided into natural organic and synthetic organics. The benefits of natural organic fertilizer were reported from the previous researches. However, the limited research results about clippings as a source of natural organic fertilizers were reported. The objective of the research to investigate effects of liquid fertilizer produced from fermented clippings for creeping bentgrass growth. Liquid fertilizer (LF) produced was used for the research to be compared with Urea and two natural organic fertilizers of different source (NO-1 and NO-2). Creeping bentgrass (Agrostis stolonifera L., L-93) was used for the study. Turfgrass quality was measured by visual evaluation every two weeks from June to October, 2011 using a scale of 1 to 9 (1=worst, 6=acceptable, and 9=best). Turfgrass disease damage was measured by percent of area damaged when a turfgrass disease occurred. LF produced lower damage than NO and urea when temperature was high. Although NO-2 produced the highest or equal to the highest turfgrass quality in June and October, LF had the highest or equal to the highest quality from July to September.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.47 no.11
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• pp.753-760
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• 2019

Sparkjet actuator, also known as plasma synthetic jet actuator, which is a kind of active flow control actuator is considered as being high possibility for the supersonic flow control due to ejecting stronger jet compared to the other active flow control actuators. Sparkjet actuator generates high temperature and high pressure flow inside the cavity by using arc plasma and leads momentum by ejecting such flow through orifice or nozzle. In this research, numerical calculation of sparkjet actuator with respect to the location of electrodes which exists inside the cavity is conducted and the change of the performance of sparkjet actuator is suggested. As the location of electrodes goes closer to the bottom of the cavity, impulse is increased and the average pressure inside the cavity maintains higher. When the location of electrode is 25% and 75% of the entire cavity height, impulse is 2.515 μN·s and 2.057 μN·s, respectively. Each impulse is changed by about 9.92% and -10.09% compared to when the location of electrodes is 50% of the entire cavity height.

• Journal of the Mineralogical Society of Korea
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• v.18 no.2
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• pp.109-115
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• 2005

Beidellite, a member of the smectite group, was synthesized hydrothermally from dickite. Physical and chemical properties of the synthetic Na-beidellite were characterized by the analytical methods of XRD, IR, TG, DTA, EDS, XRF and ICP. The result of Greene-Kelly test indicates that the synthesized smectite is Na-beidellite. IR spectrum of synthesized beidellite exhibited Al-O-H bending vibration at $818\;cm^{-1}\;and\;770\;cm^{-1}$ which was observed particularly in pure beidellite. TGA analysis revealed that the synthesized Na-beidellite comprises $16\;wt\%$ of water. DTA curve showed an endothermic peak at $117^{\circ}C$ due to dehydration reaction and peaks at $482^{\circ}C$ and $685^{\circ}C$ due to dehydroxylation reaction. The clay mineral was transformed to mullite and cristobalite at the temperature of $1028^{\circ}C$. The CEC value, Methylene Blue test and swelling capacity was determined to be $116\~118\;cmol/kg,\;84\~91\%,\;29\~32\;mL/2g$, respectively. The chemical composition of the synthesized phase was identified as $Na_{0.5}Al_{2.5}Si_{3.5}O_{10}(OH)_2$ from EDS and XRF analyses.