• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.28 no.4
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• pp.393-405
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• 2018

Objective: This study examines the types of hazardous factors in the working environment and the time-trend for their exposure levels over 10 years (2007 to 2016). Study Design and Method: The types of hazardous factors and exposure levels were drawn from the 19 measurement reports on the working environment over 10 years at a shock absorber manufacturing facility. Risk assessment of the types of factors and time-trend of exposure levels were evaluated using the factors and exposure levels. Results: A total of 34 hazardous factors were evaluated. The types were noise, 15 organic compounds, seven kinds of acid sand alkalis, eight kinds of heavy metals, and three other compounds. Special management materials used were nickel, hexavalent chrome, and sulfuric acid. Human carcinogens (1A) used were trichloroethylene, nickel, and sulfuric acid. There were six types of substances belonging to the IARC's 2B (body carcinogens) classification or higher, including, methyl isobutyl ketone, ethyl benzene, and trichloroethylene. No detection was found for 627 out of the 2065 total measurements in 19 exposure survey reports, representing 30.4%. Organic solvents, acid and alkali products, and heavy metals showed continuous low exposure concentrations. Noise, welding fumes, and the evaluation of mixed solvents show a gradual decrease in geometric mean and maximum over the time-trend of 10 years. Conclusions: In the case of a shock absorber manufacturing facility, the hazardous factors of noise and the evaluation of mixed solvents still indicate high concentrations exceeding the exposure limits and necessitate reduction studies. These two factors and welding fumes showed a continuous decrease in their ten-year tendency. Organic compounds, acids/alkalis, and heavy metals were managed smoothly in a work environment of continuous low concentrations.

• Korean Journal of Food Science and Technology
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• v.10 no.2
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• pp.143-150
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• 1978

In our previous report (Korean J. Food Sci. Technol., 9, 123. (1977), functional properties of soyprotein isolates prepared from defatted soybean meal were studied. Using those properties soyprotein fibers, which may be acceptable as meat analogs, were prepared with protein spinning apparatus. Soyprotein can be converted into the suitable form for the spinning by denaturation with alkali (0.6%) and continuous fibers were spun by extruding spinning solution into an 20% NaCl-1 N acetic acid coagulating bath. The process for producing soyprotein fibers on a bench scale was described and break strength, break elongation and textural parameters of the fibers formed were evaluated. The possible scheme of formation of soyprotein fibers was discussed.

• Korean Journal of Microbiology
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• v.5 no.2
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• pp.61-68
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• 1967

In the process of the incorporation of orthophsphate into protein and other cell constituents, the role of inorganic polyphosphate and RNA-polyphosphate complex and the correlation between them were pursued by analyzing the contents of $^{32}P$ and total P in various fractions of Chlorella cells, which had been uniformly labeled with $^{32}P$ before the inoculation in a normal "cold" medium or P-free medium during the culture. The effects of ionizing radiation and various micronutritional-element deficiencies on the phosphate incorporation into, and biosynthesis of, protein and other introgenus compounds in the cells were also observed. When the uniformly $^{32}P$-labeled algae were grown in a normal "cold" medium the contents of $^{32}$ P in the fractions of protein, DNA and RNA-polyphosphate complex increased, but those in the fraction of acid-insoluble polyphosphate decreased. On the other hand, amount of $^{32}P$in the fraction of RNA was almost unchanged in spite of rapid increase of the total P. In the growing period of $^{32}P$-labeled algae in a P-free medium, amounts of $^{32}P$ in the fractions of DNA, protein and lipid increased, while those in the fractions of RNA-polyphosphate and inorganic polyphosphates decreased. When the algal cells were irradiated with about 70, 000r of gamma-rays before the inoculation in the medium, amounts of phosphate in the fractions of DNA, RNA, nucleotides and protein decreased during the culture, compared with those of the control. However, the phosphate content in the fraction of acid-insoluble polyphosphate of the irradiated cells increased than those of the control. In the growing period of the algae in a Mo-free, medium, amounts of acid-soluble total phosphate and nucleotides of the cells increased, while the amounts of residual protein and RNA decresed compared with those of the normal cells. Amounts of alkali-labile protein and phospholipid of the cells grown in a B-free medium decreased, whereas amount of phosphate in acid-soluble fraction increased compared with the control. In general, the contents of protein and RNA in each microelement deficient cells decreased more or less, compared with those in the normal cells.in the normal cells.

• Journal of the Korean Wood Science and Technology
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• v.40 no.2
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• pp.78-90
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• 2012

Soybean hull is an attractive feedstock for glucose production. To increase the glucose conversion in acid hydrolysis, a pretreatment method combined steam explosion with alkali pretreatment for soybean hull was studied. For first step pretreatment, steam explosion conditions (log Ro 2.45) were optimized to obtain maximum solid recovery and cellulose content. In the second step pretreatment, the conditions for potassium hydroxide pretreatment of steam exploded soybean hull were optimized by using RSM (response surface methodology). The optimum conditions for minimum lignin content were determined to be 0.6% potassium hydroxide concentration, $70^{\circ}C$ reaction temperature and 198 min reaction time. The predicted lignin content was 2.2% at the optimum conditions. Experimental verification of the optimum conditions gave the lignin content in similar value with the estimated value of the model. Finally, glucose conversion of pretreated soybean hull using acid hydrolysis resulted in $97.1{\pm}0.4%$. This research of two-step pretreatment was a promising method for increasing the glucose conversion in the cellulose-to-glucose process.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.29 no.8
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• pp.455-460
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• 2016

A textured front surface is required in high efficiency silicon solar cells to reduce reflectance and to improve light trapping. Wet etching with alkaline solution is usually applied for mono crystalline silicon solar cells. However, alkali texturing method is not appropriate for multi-crystalline silicon wafers due to grain boundary of random crystallographic orientation. Accordingly, acid texturing method is generally used for multi-crystalline silicon wafers to reduce the surface reflectance. To reduce reflectivity of multi-crystalline silicon wafers, double texturing method with combination of acid and reactive ion etching is an attractive technical solution. In this paper, we have studied to optimize RIE condition by different RF power condition (100, 150, 200, 250, 300 W).

• Korean Chemical Engineering Research
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• v.46 no.3
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• pp.529-534
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• 2008

The normal shell and the regenerated oyster shell, Crassostrea gigas, are separated according to the characteristics of inner shell morphology. To study characteristics of chitin obtained from the regenerated shell, chitin prepared by acid and alkali process is analyzed by FT-IR (Fourier transform infrared spectrometer) and XRD (X-ray Diffractometer). The content of insoluble protein in the normal shell was more than doubled as compared with that in the regenerated shell. A comparison of secondary structure of the normal shell and the regenerated shell revealed that the content of random of the regenerated shell was above 47%, indicating an amount in the structural unordered state. Through amino acid composition analysis and secondary protein structure of soluble protein isolated from the normal shell and the regenerated shell, it was found that there are differences in biomineralization strategy of the regenerated shell as compared to the normal shell. The relatively low hardness of the regenerated shell is caused by the change of amino acid composition and ordered secondary protein structure as compared to hardness of the normal shell.

• The Korean Journal of Ecology
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• v.6 no.4
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• pp.243-249
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• 1983

Absorption pattern of potassium, calcium, phosphate and nitrate ions, and the pH change during ion-absorption at pH 3.0-11.0 by Oryza sativa L. were studied to investigate indirectly the evidence of H^+-efflux by ATPase. The rice seedlings which were grown either in $L^{\circ} -dark or in L^+-sunlight$, were used both in each ion-absorption to compare with one another. The uptake rate of these ions appeared to favor more in $L^+than in L^{\circ}$, over all range in pH, nearly with the same pattern. The absorption of potassium resulted in bell shape and that of calcium increased linearly to the alkali range. The shape of phosphate-absorption showed nearly the t-distribution curve with high value in acid range and the uptake of nitrate resulted in the dual peaks, but higher in acid range. The pH of the external solution changed from the range of 3.5-11.0 to 3.5-7.0 after lhr-absorptioin, and further acidified after 3hr-absorption. It is suggested that the pH change of the external solution be affected by $ H^+-efflux$ which may be caused by the ATP-hydrolysis.

• Journal of the East Asian Society of Dietary Life
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• v.5 no.3
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• pp.255-262
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• 1995

Studies were carried out to investigate physicochemical properties of taro during the pretreatment process of making Toranbyung. Seventeen kinds of amino acids were found in taro. Aspartic acid and glutamic acid were most plentiful among those amino acids. Essential amino acids were about 42.7% of the total amino acids. Sulfur containing amino acids, mehtionine and cystine were about 2.7% The amylograph indicated that the initial temperature triggering gelatinization of both rice flour mixed with taro and glutinous rice flour mixed with taro increased as the amount of taro increased. But the maximum viscosity of rice flour mixed with taro did not increase as the amount of taroincreased while the maximum viscosity of glutinous rice flour mixed with taro increased as the amount of taro increased. And the peak temperature of both rice flour mixed with taro and glutinous rice flour miced with taro increased as the amount of taro increased. The alkali degree of insoluble ash was higher than that of soluble ash. Glutinous rice dough had more total sugar than rice dough. Yellowness of rice dough was higher than that of glutinous rice dough.

• Journal of Adhesion and Interface
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• v.23 no.4
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• pp.108-115
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• 2022

In this study, we synthesized poly(itaconic acid-co-acrylamide) (IAcAAM) used as a novel polymer adhesion promoter to improve the adhesion strength of surface-treated Cu lead frames and epoxy composites. IAcAAM comprising itaconic acid, acrylamide was prepared through radical aqueous polymerization. The chemical structure and properties of IAcAAM was analyzed by FT-IR, ¹H-NMR, GPC, and DSC. The surface of the copper lead frame was treated with high temperature, alkali, and UV ozone to reduce the water contact angle and increase the surface energy. The adhesive strength of Cu lead frame and epoxy composite increased with the decrease of contact angle. The adhesive strength of Cu lead frame/epoxy composite increased with the addition of IAcAAM in epoxy composite. As silica content increased, the adhesive strength of Cu lead frame and epoxy composite tended to slightly decrease.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.49 no.3
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• pp.160-166
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• 2004

This study was carried out to get the basic informations regarding the varietal variations for the physicochemical properties such as protein content, amylose content, fatty acid content, grain quality values and color properties such as lightness value, chroma and hue for the 164 recombinant inbred lines(RILs) of Milyang 23 and Gihobyeo(M/G) at the experimental farm in the Sangji University. The principal component analysis and heritability study were conducted for this experiments. The rapidity of grain filling(RCF) for the 164 M/G RILs could be classified into four groups such as slow maturing group less than 41％, mid-slow maturing group 41∼60％, fast maturing group 61∼80％ and very fast maturing group more than 81％ based on the rapidity of grain filling rate. The slow maturing group of RGF showed a little bit higher protein content 9.1％, compared to the other RGF groups. However, the amylose content of all the RGF groups revealed the same content by the groups. The very fast maturing group of RGF showed longer grain length in brown rice compared to other RGF varietal groups, in case of grain width in brown rice showed shorter than any other groups. The alkali digestive value which was so much related to gelatinization temperature showed 3.40 degree at fast maturing group of RGF in M/G RILs. However, the very fast maturing group of RGF revealed 4.31 degree of alkali digestive value. The principal component analysis was performed by the chemical and color properties such as quality value, protein content, amylose content, alkali digestive value, fatty acid content, lightness value, chroma and hue for M/G RILs. The first principal component was able to explained upto 36％ to total informations. It was corresponded to quality value, protein content, amylose content, fatty acid content, lightness value and a-value(green -1 red). The characters regarding grain quality showed high heritable properties more than 75％ of heritability, but color characters appeared relatively lower heritability compared to grain quality.