• Journal of Applied Biological Chemistry
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• v.65 no.3
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• pp.173-181
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• 2022

This study was carried out to investigate the residual characteristics of flubendiamide in kale to establish pre-harvest residue limits (PHRL) and the removal efficiency according to the washing solvent and method. Field tests were conducted at two different greenhouses, field 1 (Anseong-si, Gyeonggi-do) and field 2 (Incheon-si, Gyeonggi-do). According to the safe use guidelines kale was sprayed with flubendiamide twice every 10 days and harvested 0 (after 2 h), 1, 2, 3, 5, 7 and 10 days after the final application. The biological half-live of flubendiamide in kale was calculated based on dissipation curves of the pesticide in samples analyzed by liquid chromatography coupled with tandem mass spectrometry. In the analysis, method limits of quantitation (MLOQ) were 0.01 mg/kg, and recoveries performed with two different fortification levels of 10 MLOQ and maximum residue limit (0.7 mg/kg) were 104.2±3.6 and 101.9±10.2%, respectively. The dissipation rate constant of flubendiamide in kales were 0.2437 at field 1 and 0.1981 at field 2. PHRL calculation equations obtained using the dissipation constants estimated as follows: if the residual concentration of flubendiamide in kale on 10 days before harvest is less than 8.0 mg/kg, the residual concentration on the harvest would be under MRL. The removal of flubendiamide from kale was the greatest when it was washed with vinegar (39.8%), followed by baking soda (31.7%), calcium powder (30.2%), neutral detergent (27.2%), and tap water (15.9%). The results of this study would be useful for both farmers and consumers to produce or consume safe agricultural products.

• Journal of the Korean Geosynthetics Society
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• v.22 no.3
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• pp.87-95
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• 2023

Recently, redevelopment of the original downtown area is underway, the necessity of construction in adjacent location is increasing. However, excavations in dense urban areas are prone to ground problems due to various causes, so it is necessary to use materials and methods that can minimize such problems. As a general earth retaining method, various methods such as diaphragm wall and CIP method are applied using cement. However, since a large amount of cement is used for the installation of earth retaining method, it is necessary to conduct research on the development of new cement substitute materials to significantly reduce greenhouse gas emissions. In this study, we utilized the hardening reaction of blast furnace slag powder, desulfurized gypsum and high calcium fly ash by alkali activation and applied it to the SCW method. As a result, it was analyzed that the compressive strength of solidified soil using development solidification material was 96.2 ~ 106.3% of OPC at 28 days of curing. In addition, the strength increment ratio was 2.06 for sandy soil and 2.41 for clayey soil, which was higher than 1.85 of OPC. It seems an advantageous in terms of long-term strength. In addition, from the environmental point of view, it was analyzed that there is no elution of heavy metals and that greenhouse gas emissions can be dramatically reduced. Therefore, if further studies are conducted, it can be applied to the SCW method.

• Analytical Science and Technology
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• v.20 no.6
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• pp.516-523
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• 2007

Purification of silica mineral has been investigated by acid leaching of pulverized silica. A series of studies has been carried out on the effect of leaching silica powder as a function of the leaching time at the constant temperature of $80^{\circ}C$ in oxalic acid, aqua regia, and two mixed acids of HF/HCl, $HF/HNO_3$. The impurities of silica and leachantes were measured by neutron activation analysis (NAA), inductively coupled plasma atomic emission spectrometry (ICP-AES), atomic absorption spectrometry, x-ray fluorescence (XRF) method and wet analysis (WA). Certain metals, such as sodium, calcium, iron, aluminium and titanium, have been found in concentrations of hundreds or even thousands of mg/kg. Comparison of purification processes of silica and analytical methods of impurities in the silica was conducted in this study.

• Korean Journal of Hazardous Materials
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• v.2 no.1
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• pp.18-26
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• 2014

We analyzed the demand of competent authorities requiring adequate technical information for initial investigation of chemical accidents. Reflecting technical reports on chemical accident response by environmental agencies in the U.S. and Canada, we presented information on environmental diffusion and toxic effects available for the first chemical accident response. Hydrogen fluoride may have the risk potential to corrode metals and cause serious burns and eye damages. In case of inhalation or intake, it could have severe health effects. The substance itself is inflammable, but once heated, it decomposes producing corrosive and toxic fume. In case of contact with water, it can produce toxic, corrosive, flammable or explosive gases and its solution, a strong acid, may react fiercely with a base. In case of hydrogen fluoride leak, the preventive measures are to decrease steam generation in exposed sites, prevent the transfer of vapor cloud and promptly respond using inflammable substances including calcium carbonate, sodium bicarbonate, ground limestone, dried soil, dry sand, vermiculite, fly ash and powder cement. The method for fire fighting is to suppress fire with manless hose stanchions or monitor nozzles by wearing the whole body protective clothing equipped with over-pressure self-contained breathing apparatus from distance. In case of transport accident accompanied with fire, evacuation distance is 1,600m radius. In cae of fire, fire suppression needs to be performed using dry chemicals, CO₂, water spray, water fog, and alcohol-resistance foam, etc. The major symptoms by exposure route are dyspnoea, bronchitis, chemical pneumonia and pulmonary edema for respiration, skin laceration, dermatitis, burn, frostbite and erythema for eyes, and nausea, diarrhea, stomachache, and tissue destruction for digestive organs. In atmosphere, its persistency is low, and its bioaccumulation in aquatic organism is also low.

• Journal of the Korean Recycled Construction Resources Institute
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• v.11 no.4
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• pp.509-516
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• 2023

The use of sulfur(S) in concrete has been variously studied as a way to improve salt resistance in concrete. However, sulfur is a solid material and is difficult to powder, which has disadvantages in its usability as an admixture or mixture for cement and concrete. For these problem, polymers such as dicyclopentadiene have been used to modify sulfur, but this also exists in a sticky state after modifying and does not improve the fundamental problem. So, reforming sulfur with slaked lime and the effect on cement hydration was examined by reforming sulfur with slaked lime, and the following conclusions were obtained. Depending on the reaction conditions, slaked lime modified bio-sulfur exists in a slurry state containing unreacted sulfur, unreacted slaked lime, calcium-sulfur(Ca-S) compounds and water. When slaked lime modified bio-sulfur is used as a cement mixture, salt resistance of concrete with slaked lime modified bio-sulfur is to be superior to that of plain concrete. This is believed to be because structure of cement hydrates with slaked lime modified bio-sulfur is to be more dense to that of plain cement hydrates by the continued presence of ettringite and can be used as a cement mixture in concrete.

• Journal of the Korean Chemical Society
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• v.42 no.6
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• pp.618-628
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• 1998

Pure CaO, Mn-doped CaO, Mn/CaO, and K/CaO catalysts were prepared and tested as catalysts for the oxidative coupling of methane in the temperature range of 600 to 800$^{\circ}C$ to investigate the effects of Mn- and K-addition on the catalytic activity of calcium oxide. To characterize the catalysts, X-ray powder diffraction(XRD), XPS, SEM, DSC, and TG analyses were performed. The catalytic reaction was carried out in a single-pass flow reactor using on-line gas chromatography system. Normalized reaction conditions were generally $p(CH_4)/p(O_2)=250$ Torr/50 Torr, total feed flow rate=30 mL/min, and 1 atm of total pressure with He being used as diluent gas. Among the catalysts tested, 6.3 mol% Mn-doped CaO catalyst showed the best $C_2$ yield of 8.0% with a selectivity of 43.2% at 775$^{\circ}C$. The $C_2$ selectivity increased on lightly doped CaO catalysts, while decreased on heavily doped CaO([Mn] > 6.3 mol%) catalysts. 6 wt.% Mn/CaO and 6 wt.% K/CaO catalysts showed the $C_2$ selectivities of 13.2% and 30.9%, respectively, for the reaction. Electrical conductivities of CaO and Mn-doped CaO were measured in the temperature range of 500 to 1000$^{\circ}C$ at Po2's of $10^{-3}\; to\;10^{-1}\;atm.$ The electrical conductivity was decreased with Mn-doping and increased with increasing $P0_2$in the range of $10^{-3}\;to\;10^{-1}\;atm,$ indicating the specimens to be p-type semiconductors. It was suggested that the interstitial oxygen ions formed near the surface can activate methane and the formation of interstitial oxygen ions was discussed on the basis of solid-state chemistry.

• Journal of Veterinary Clinics
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• v.6 no.2
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• pp.227-259
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• 1989

Waterpepper is a weed which grows on damp soil. especially near swamps, and in shallow water of ponds and ditches. It Is widespread throughout the country In abundant colonies. In the present experiments, possible toxic effects of waterpepper were investigated in ruminants. Pour cows were fed waterpepper ad libitum or by force in the from of green forage, hay and/or powder, 8 goats were administered in the form of methanol extract, and 4 goats, crude juice, into the lumen. Clinical signs were examined as well as urinalysis, hematology, serum chemical analysis, pH/blood gas analysis and chclinesterase activities following administration of waterpepper. Six goats which were administered the methanol extract or crude juice were sacrificed for pathological examinations., In addition to the clini copathological examinations, the chemical constituents of waterpepper were qualitively analyzed from the methanol extract and the Effects of the waterpepper crude juice were examined on the motility of rabbit duodenum and uterus. It is revealed that waterpepper contains steroids, terpenoids, flavonoids, tannin and essential oils in the methanol extract and nitrates in the crude juice. The crude juice of waterpepper relaxed the rabbit uterine and duodenal smooth muscles. The constraction of duodenum by acetylcholine or BaCl$_2$ were partially inhibited by pretreatment of the crude juice. However, the relaxation of duodenum by the crude juice was not blocked by the pretreatments of phenoxybenzamlne, propranolol, cocaine, reserpine and tetrodotoxin. The constituents of waterpepper to evoke elaxation of duodenal smooth muscle were stable to heat. The cows administered waterpepper showed common clinical symptoms such as acrid expression, restlessness, dullness, inappetence, anorexia, severe diarrhea, mild bloat and left displacement of abomasum, while bloody feces was shown in a cow. The goats administered the mothanol extract showed common clinical signs such as acrid expression, restlessness, dullness, inappetence and soft feces, while bloody feces was shown in a goat, A goat adminstered the crude juice showde bloody feces and diarrhea. Respiratory rates and heart beats were increased along with diarrhea in the experimental cows. The erythrocyte counts and MCHC were decreased whereas PCV, MCV and neutrophils were increased in the cows administered waterpepper. In goats administered methanol extract, there were decreases in erythrocytes, PCV and hemoglobin content, and an increase in MCHC. The goats ingester with the crude juice showed negligible changes in hematologic values compared with control group which was administered the same amount of water instead of the crude juice. The contents of serum calcium, Inorganic phosphorus, magnesium, Iron, glucose, cholesterol, total protein, triglycerides and phospholipids were tended to decrease in cows. In goats serum iron, glucose, triglycerides, cholesterol, BUN and phospholipids content were decreased while the content of sodium and chloride were increased after administration of the methamol extract The goats ingested with the crude juice did not show significant changes in serum chemical analysis. Even though there were some pathological findings such as hyperemia in the small intestines and kidneys and swelling of liver parenchymal cells, the values of serum AST, ALT, LDH, alkaline phosphatase, total bilirubin and creatinine did not change significantly. While proteins, hemoglobin and blood were detected in the urine of cows, urine pH, ketone bodies, glucose, bilirubin and urobilinogen content were normal or undetected. There were no significant changes in pH/bolld gas analysis data of cows and cholinesterase activities of plasma and erythrocytes of cows and goats ingested with waterpepper or the methanol extract. It is concluded that waterpepper irritates the gatrointestinal system, causes abdominal pain, relaxes the gastrointestinal smooth muscle and dilatates blood vessels supplied to the system. The irritation and relaxation may lead to abnormal fermentation, maldigestion and malabsorption of nutrients and result in diarrhea, body feces, mild bloat and left displacement of abomasum.

• Applied Biological Chemistry
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• v.27
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• pp.47-55
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• 1984

The results of series studies on the ratio of supplements, out-door composting and out-door fermentation induced by using the rice straw as a main substrates at the cultivation of Agaricus bisporus, and the cultivation of Pleurotus ostreatus using the rice straw bundles on its compost are as follows; When rice straw for cultivation of A. bisporus was used as the main substrates in synthetic compost as a carbon source, yields were remarkably high. Fermentation was more rapid than that of barley straw or wheat straw and the total nitrogen content was high in rice straw compost. Use of barley straw compost for cultivation of A. bisporus was shown of low yield compared with rice straw, but when a 50% barley straw and 50% rice straw mixture was used, the yield was almost the same as that using only rice straw. The total organic nitrogen on the compost were shown the positive relation to the yield of A. bisporus, but the ammonium nitrogen negative relation to the mycelial growth and yield of A. bisporus. When rice straw was used as the main substrate for compost media, urea was the most suitable source of nitrogen. Poor results were obtained with calcium cyanamide and ammonium sulfate. When urea was applied three separate times, nitrogen loss during composting was decreased and the total nitrogen content of compost was increased. The supplementation of organic nutrient activated compost fermentation and increased yield of A. bisporus. The best sources of organic nutrients selected were as follows: perilla meal, sesame meal, wheat bran and poultry manure, etc. Soybean meal, tobacco powder and glutamic acid fermentation byproducts which were industrial wastes, could be substituted for perilla meal, sesame meal and wheat bran as organic nutrient sources for compost media. During out door composing of rice straw for cultivation of A. bisporus, using of tuner, composter and tunnel system increased up to 13% of its yield, and also cut down 34% of production Cost. The cultivation of P. ostreatus and utilizing of rice straw and wheat straw was established and its yield was high on the rice straw pots. When the substrates 'Rice straw' was heated by steam at $60^{\circ}C$ for 6 hr. mycelial growth of P. ostreatus was moderately rapid and its yield was high.

• Korean Journal of Dental Materials
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• v.45 no.4
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• pp.257-274
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• 2018

The purpose of this study was to evaluate the effect of acid-treatment conditions on the surface properties of the RBM (Resorbable Blast Media) treated titanium. Disk typed cp-titanium specimens were prepared and RBM treatments was performed with calcium phosphate ceramic powder. Acid solution was mixed using HCl, $H_2SO_4$ and deionized water with 4 different volume fraction. The RBM treated titanium was acid treated with different acid solutions at 3 different temperatures and for 3 different periods. After acid-treatments, samples were cleaned with 1 % Solujet solution for 30 min and deionized water for 30 min using ultrasonic cleanser, then dried in the electrical oven ($37^{\circ}C$). Weight of samples before and after acid-treatment were measured using electric balance. Surface roughness was estimated using a confocal laser scanning microscopy, crystal phase in the surface of sample was analyzed using X-ray diffractometer. Surface morphology and components were evaluated using Scanning Electron Microscope (SEM) with Energy Dispersive X-ray spectroscopy (EDX) and X-ray Photoemission Spectroscopy (XPS). Values of the weight changes and surface roughness were statistically analyzed using Tukey-multiple comparison test (p=0.05). Weight change after acid treatments were significantly increased with increasing the concentration of $H_2SO_4$ and temperature of acid-solution. Acid-treatment conditions (concentration of $H_2SO_4$, temperature and time) did not produce consistent effects on the surface roughness, it showed the scattered results. From XRD analysis, formation of titanium hydrides in the titanium surface were observed in all specimens treated with acid-solutions. From XPS analysis, thin titanium oxide layer in the acid-treated specimens could be evaluated. Acid solution with $90^{\circ}C$ showed the strong effect on the titanium surface, it should be treated with caution to avoid the over-etching process.

• Korean Journal of Soil Science and Fertilizer
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• v.4 no.1
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• pp.13-19
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• 1971

In order to establish the method of improving ill drained paddy soil where the accumulation of absorption inhibitor is worried in the earlier stages of rice growth, proper soil is selected and an field experiment is designed having treatments such as lime materials, none sulfate fertilizers, boron and straw etc. The data of yield and plant analysis in different stages of rice growth is eveluated and discussed to obtain following summaries. (1) Significant yield increase was made by the treatment of lime materials such as slacked lime or wollastonite powder, materials inhibiting the activity of microorganisms such as boron and of none sulfate fertilizers lacking inhibitor producing sources. (2) The crop scientifice causes of decreasing yield are the decreasing the number of panicles per hill, grains per panicle and the weight of grains. (3) The plant nutritional causes of decreasing yield are the lowering of nitrogen content throughout the life, phosphate content since young premodia formation stage of plant and the decreased content of magnesium, calcium and silicate in straw at harvesting stage. (4) The causes of lowering the content of various elements in rice plant grown in ill drained paddy soil are suggested as root damage by producing and accumulating absorption inhibitors such as organic acids and hydrogen sulfide etc, from the following observed facts; (a) In young premodia formation stage, attaining to the maximum production and accumulation of absorption inhibitor, the phosphate accumulation in plant was smaller in the phosphate plots than without phosphate plots and much higher in the neutralized plots by adding lime materials. (b) In the plots of straw addition, the potassium content in plant at the young premodia formation stage is very low probabley due to root damage by absorption inhibitor produced from the process of straw decomposition but higher at the stage of harvesting probably due to the immetabolic negative absorption of damaged roots. (c) The effect of boron, known as the inhibitor of microorganism activity to decompose organic matter, is apparent. (d) The effect of nonsulfate fertilizer treatment, having no source of producing inhibitor such as hydrogen sulfide, was significant. (e) All the yield components, decided around the young premodia formation stage attaining to the maximum inhibitor concentration in soil and minimum root activity, are significantly decreased.