• Journal of the Korea institute for structural maintenance and inspection
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• v.14 no.3
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• pp.171-177
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• 2010

As concrete structures are exposed to chemical substances, damaged from salt, or progressed to the neutralization, the surface damage of the structures is generated timely fashion, resulting shortened service life. Especially, the sulfate erosion causes rapid surface defects, and the steel skeleton becomes corroded due to the water infiltration, generating stability deterioration of the concrete structure. In this study, the physical characteristics of the acid-resistant mortar with aluminosilicates was investigated in order to resolve problems of the acid resistance, one of the most serious problems of the cement type repair material. As the result of the experiment, the test specimen turned to exhibit almost equivalent physical characteristics with those of concrete sectional repair materials in terms of compressive and bending strengths. As both the cement sectional repair material and the test specimen were immerged in sulfuric acid solution to examine weight changes, the test specimens exhibited only 4% loss of their weights while the cement sectional repair materials reached at the level of 80% or above, proving the excellence acid resistant characteristics of the test specimens. Consequently, the physical characteristics of acid resistant mortar with aluminosilicates were revealed to be superior than those of concrete sectional repair materials. It can be utilized as a sectional repair material where the acidic erosion is anticipated.

• Journal of the Korean Society of Food Science and Nutrition
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• v.20 no.2
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• pp.139-147
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• 1991

The preservative effect of cellophane film packing on the quality of semi-salted and dried mackerel was studied. The product(P) of semi-salted and dried mackerel was prepared from raw mackerel by filleting, cleaning, soaking in 15%9v/w) salt solution for 30min, draining, packing with cellophane film (PT# 300, thickness:$20{\mu}{\textrm}{m}$) and drying for 4 hrs at $40^{\circ}C$ in hot air dryer. The product (C) was also prepared without cellophane film packing after draining. The product (C) and (P) were stored at $5.0{\pm}0.5^{\circ}C$. After processing and during storage, moisture content of product (P) was higher than that of product (C), but contents of VBN(volatile basic nitrogen), amino nitrogen and TMA of product (P) on dry basis were lower than those of product (C). Viable cell count, TBA value, peroxide value and decreasing rate of polyenoic acid of product (P) were also lower than those of product (C). In sensory evaluation, the shelf life of product (C) was about 9 days and that of product (P) was about 14 days. From the results of chemical and sensory evaluation, it was concluded that cellophane film packing was a good condition for preserving the quality of semi-salted and dried mackerel.

• Korean Journal of Soil Science and Fertilizer
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• v.40 no.5
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• pp.349-353
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• 2007

To investigate the effect of NaCl concentration on plant growth in three halophytes, Suaeda asparagoides, Suaeda maritima, and Salicornia herbacea, and to select afforestation species for reclaimed land along the shore, this experiment was conducted by ebb and flow system added fertilize of 1/2 Hoagland solution and halophytes were cultured for 4 month treated by 0, 50, 200, 400 mM NaCl, respectively. The shoot height was increased with 0 and 50 mM NaCl treatment of Suaeda asparagoides and Suaeda maritima and decreased with 200, 400 mM NaCl treatment, whereas them of Salicornia herbacea was increased by 200 mM NaCl treatment. The higher NaCl concentrations, the lower fresh and dry weight in Suaeda asparagoides. In case Suaeda maritima and Salicornia herbacea, fresh and dry weight was increased by 200 mM NaCl treatment. The higher NaCl concentrations, the lower chlorophyll contents in shoot of all treatment. The proline contents of 400 mM treatment in Suaeda maritima was higher than them of other treatments. The shoot water potential was generally lower in 50mM as compared to the control in Suaeda asparagoides, Suaeda maritima, significantly.

• Resources Recycling
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• v.30 no.1
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• pp.44-52
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• 2021

This study investigated the effect of the type of alkaline precipitant used on the synthesis of lithium hydroxide by examining the behavior of lithium hydroxide produced using lithium sulfate recovered from a waste lithium secondary battery as a raw material. The double-replacement reaction (DRR) process was used to remove the impurities contained in the lithium salt precursor of lithium sulfate and to improve the efficiency of the synthesis of lithium hydroxide. The experiment was conducted by control the molar ratio of the precursor ([Li]/[OH]), the reaction temperature, and the composition of the alkaline precipitant (KOH, Ca(OH)2, Ba(OH)2) used for the production of highly-crystalline lithium hydroxide. A secondary solid-liquid separation was performed following the reaction to remove the impurities generated, and the purified aqueous solution of lithium hydroxide was evaporated to remove the moisture and obtain the product as a powder. The crystallinity and synthesis behavior of the product were examined.

• Journal of Food Hygiene and Safety
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• v.33 no.6
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• pp.460-465
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• 2018

Deep sea water is deeper than 200 m in depth and maintains cool temperatures. It is clean seawater not contaminated by E. coli and other general bacteria. Because deep sea water is a recyclable resource with high industrial value, activities for commercial use are vigorously developing. We investigated safety, quality characteristics, and mineral contents of prototype products using deep sea water as a substitute for a curing agent and compared it with existing commercially processed products. This study examined the potential of deep sea water as an alternative to curing agent solution. As a result, safety and quality characteristics of processed meat products with deep sea water were not different from commercially processed meat products, but mineral contents were higher in processed meat products with deep sea water. Deep sea water could be widely used as purity salt and purity minerals that can replace chemical substances such as chemical salts. A new, active food market using deep sea water will emerge in the near future.

• Journal of Food Hygiene and Safety
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• v.36 no.6
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• pp.474-480
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• 2021

Sodium alginate is the sodium salt of alginic acid, commonly used as a food additive for stabilizing, thickening, and emulsifying properties. A relatively simple and universal analysis method is used to study sodium alginate due to the complex pretreatment process and extended analysis time required during the quantitative method. As for the equipment, HPLC-UVD and Unison US-Phenyl column were used for analysis. For the pretreatment condition, a shaking apparatus was used for extraction at 150 rpm for 180 minutes at room temperature. The calibration curve made from the standard sodium alginate solution in 5 concentration ranges showed that the linearity (R²) is 0.9999 on average. LOD and LOQ showed 3.96 mg/kg and 12.0 mg/kg, respectively. Furthermore, the average intraday and inter-day accuracy (%) and precision (RSD%) were 98.47-103.74% and 1.69-3.08% for seaweed jelly noodle samples and 99.95-105.76% and 0.59-3.63% for sherbet samples, respectively. The relative uncertainty value was appropriate for the CODEX standard with 1.5-7.9%. To evaluate the applicability of the method developed in this study, the sodium alginate concentrations of 103 products were quantified. The result showed that the detection rate is highest from starch vermicelli and instant fried noodles to sugar processed products.

• Analytical Science and Technology
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• v.19 no.2
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• pp.131-141
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• 2006

Hydrobromic acid salt of a $N_2O_2$ tetradentate ligand, N,N'-bis(2-hydroxybenzyl)-ethylene-diamine ($H-BHE{\cdot}2HBr$) was synthesized. $Br-BHE{\cdot}2HBr$, $Cl-BHE{\cdot}2HBr$, $CH_3-BHE{\cdot}2HBr$ and $CH_3O-BHE{\cdot}2HBr$ having Br, Cl, $CH_3$ and $CH_3O$ substituents at 5-position of the phenol group of $H-BHE{\cdot}2HBr$ were also synthesized. $Nap-BHE{\cdot}2HBr$ having naphthalen-2-ol instead of the phenol group was also synthesized. The potentiometry study in aqueous solution revealed that the proton dissociations of the synthesized ligands occurred in four steps and the order of the calculated overall proton dissociation constants (${\log}{\beta}_p$) of each ligand was Br-BHE < Cl-BHE < H-BHE < Nap-BHE < $CH_3$-BHE < $CH_3O$-BHE. The order showed a similar trend to that of Hammett substituent constants(${\sigma}_P$). The order of the stability constants (${\log}K_{ML}$) was CO(II) < Ni(II) < Cu(II) > Zn(II) > Cd(II) > Pb(II). The order in their stability constants (${\log}K_{ML}$) of each transition metal complex agreed well with that of the overall proton dissociation constants (${\log}{\beta}_p$).

• Analytical Science and Technology
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• v.37 no.3
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• pp.143-154
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• 2024

In this study, we improved the vitamin C test method and reviewed data on the adjustable range of chromatography conditions for quantification. First, we adjusted the mobile phase conditions such as solvent composition, salt concentration, pH and column temperature and in particular, it was confirmed through an improved test method that the peak derived from the buffer solution could be clearly separated from the target component, vitamin C by adjusting the pH. The retention time of vitamin C was partially changed by adjusting the column diameter, length and particle size but the number of theoretical plates indicated similar values and did not affect the separation and quantitative analysis of the target component. The flow rate according to the column specifications was derived from the equation proposed by the U.S. FDA (Food and Drug administration) and the Korean MFDS (Ministry of Food and Drug Safety), and evaluation of the applicability to vitamin complexes showed high selectivity for vitamin C even with altered stationary phase conditions and flow rates. In conclusion, vitamin C can be optimally separated and detected by changing the chromatographic method conditions and it was confirmed that the mobile and stationary phase conditions of liquid chromatography can be slightly adjusted in case the assay method uses an isocratic elution.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.59 no.2
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• pp.139-143
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• 2014

This study was conducted to investigate the germination and growth response by Salinities of Spergularia marina Griseb grown in the western coastal region in South Korea. The germination was investigated for 10 days at temperature $10^{\circ}C$, $15^{\circ}C$, $20^{\circ}C$, $25^{\circ}C$ in order to examine the germination of Spergularia marina Griseb by NaCl concentration 0.0, 0.3, 0.5, 1.0, 2.0%. The germination of NaCl concentration 0.0~1.0% was 90% over at $15^{\circ}C$ treatment, but the germination of NaCl concentration 2.0% was 0% at all temperature treatments. To identify the growth response of Spergularia marina Griseb according to the salinity, Spergularia marina Griseb was cultivated for 8 weeks in Hoagland culture medium and sea water. In nutrient solution culture, growth was best in NaCl 50mM among 0~400 mM concentrations and in 0, 12.5, 25, 50, 100% of sea water, growth was best in 12.5% (dilution ratio with fresh water) treatment. Spergularia marina Griseb's inorganic component contents according to salinity showed that $Na^+$ content increased, but contents of $K^+$, $Ca^+$, $Mg^+$ decreased. As a result, appropriate condition for Spergularia marina Griseb's germination is considered to be maintained at $15^{\circ}C$ and in less than NaCl 1.0% of salinity. When nutrient solution culture, NaCl 0.3% of treatment level is considered to be the optimum salinity.

• Korean Journal of Food Science and Technology
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• v.9 no.2
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• pp.123-130
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• 1977

A laboratory study was made to develop a simple and economic model method for the systematic determination of functional properties of 'Soy Protein Isolates (SPI)' prepared from defatted soybean meal. These are required to evaluate and to predict how SPI may behave in specific systems and such proteins can be used to simulate or replace conventional proteins. Data concerning the effects of pH, salt concentration, temperature, and protein concentration on the functional properties which include solubility, heat denaturation, gel forming capacity, emulsifying capacity, and foaming capacity are presented. The results are as follows: 1) The yield of SPI from defatted soybean meal increased to 83.9 % as the soybean meal was extracted with 0.02 N NaOH. 2) The suitable viscocity of a dope solution for spinning fiber was found to be 60 Poises by using syringe needle (0.3 mm) with 15 % SPI in 0.6 % NaOH. 3) Heat caused thickening and gelation in concentration of 8 % with a temperature threshold of $70^{\circ}C$. At $8{\sim}12\;%$ protein concentration, gel was formed within $10{\sim}30\;min$ at $70{\sim}100\;^{\circ}C$. It was, however, disrupted rapidly at $125\;^{\circ}C$ of overheat treatment. The gel was firm, resilient and self-supporting at protein concentration of 14 % and less susceptible to disruption of overheating. 4) The emulsifying capacity (EC) of SPI was correlated positively to the solubility of protein at ${\mu}=0$. At pH of the isoelectric point of SPI (pH 4.6), EC increased as concentration of sodium chloride increased. Using model system$(mixing\;speed:\;12,000\;r.p.m.,\;oil\;addition\;rate:\;0.9\;ml/sec,\;and\;temperature\;:\;20{\pm}1\;^{\circ}C)$, the maximum EC of SPI was found to be 47.2 ml of oil/100 mg protein, at the condition of pH 8.7 and ${\mu}=0.6$. The milk casein had greater EC than SPI at lower ionic strength while the EC of SPI was the same as milk casein at higher ionic strength. 5) The shaking test was used in determining the foam-ability of proteins. Progressively increasing SPI concentration up to 5 % indicated that the maximum protein concentration for foaming capacity was 2 %. Sucrose reduced foam expansion slightly but enhanced foam stability. The results of comparing milk casein and egg albumin were that foaming properties of SPI were the same as egg albumin, and better than milk casein, particularly in foam stability.