• Journal of the Korean Ceramic Society
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• v.26 no.1
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• pp.100-108
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• 1989

Aluminum hydroxides were prepared by the alkoxide hydrolysis method using Al-isopropoxide as a starting material and NH4OH as a catalytic agent. When Al-isopropoxide was hydrolyzed in a H2O-NH3 system, only Al(OH)3 was obtained over all pH values. However, AlOOH was formed besides Al(OH)3 when Al-isopropoxide was hydrolyzed in a H2O-NH3-isopropyl alcohol system. The AlOOH/Al(OH)3 ratio was increased as the isopropyl alcohol content was increased. The hydroxides, Al(OH)3 and AlOOH, obtained in this study and the commerical products, $\alpha$-Al2O3 and AlOOH were subjected to the carbothermal reduction and nitridation reaction to product AlN powder, using carbon black as a reducing agent under N2 atmosphere at various temperatures. AlN was synthesized from the obtained Al(OH)3 and the commercial AlOOH at 145$0^{\circ}C$, however, synthesized from the obtained AlOOH and the commercial alpha-alumina at 135$0^{\circ}C$. The temperature difference is assumed to be attributed to the reactivity of those powders. AlN powder prepared from the Al-isopropoxide was observed to have the narrower particle size distribution than that prepared from the commercial $\alpha$-Al2O3 or AlOOH.

• Archives of Pharmacal Research
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• v.29 no.12
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• pp.1096-1101
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• 2006

Armeniacae Semen not only contains amygdalin, but emulsin also, which is an enzyme that hydrolyzes amygdalin. The extraction yield of amygdalin from Armeniacae Semen was low, due to the presence of emulsin, when extracted with water. When Schizandrae Fructus solution was used as the extractant; however, amygdalin was almost completely extracted, regardless of the cutting size, due to the absence of the influence of emulsin. In addition, when the crude powder or small piece forms were used with Schizandrae Fructus solution, on epimerization of the D-amygdalin into neoamygdalin occurred. D-amygdalin and its conversion product, neoamygdalin, were quantitatively analyzed by reverse-phase, high-performance liquid chromatography (HPLC), with an optimized eluent of 10 mM sodium phosphate buffer (pH 2.3), containing 11.5% acetonitrile. The concentration and detector response were linearly correlated over the range 0.05 to 2 mM. The detection limits for both D-amygdalin and neoamygdalin were approximately $5\;{\mu}M$ for the amount injected.

• Journal of the East Asian Society of Dietary Life
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• v.20 no.3
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• pp.433-438
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• 2010

To manufaure cookies with blueberry, cookies with 0%, 1%, 3%, 5%, or 7% added blueberry were prepared and tested for quality. Their pH was decreased by addition of blueberries' addition, and the influence of the pH also decreased the sugar level. For the cookies' color, L and b (yellowness) were decreased, and a was increased. The same result was shown when anthocyanin foods were added. Cookies' diameter, spreadability, and thickness were increased as blueberries were added. The cookies' hardness was lowered with increasing addition of blueberries. 3% and 5% blueberry-added cookies received the highest sensory-test scores, so these blueberry cookie showed its possibility of success to develop it as a product.

• Journal of Powder Materials
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• v.23 no.6
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• pp.447-452
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• 2016

Neodymium-iron-boron (Nd-Fe-B) sintered magnets have excellent magnetic properties such as the remanence, coercive force, and the maximum energy product compared to other hard magnetic materials. The coercive force of Nd-Fe-B sintered magnets is improved by the addition of heavy rare earth elements such as dysprosium and terbium instead of neodymium. Then, the magnetocrystalline anisotropy of Nd-Fe-B sintered magnets increases. However, additional elements have increased the production cost of Nd-Fe-B sintered magnets. Hence, a study on the control of the microstructure of Nd-Fe-B magnets is being conducted. As the coercive force of magnets improves, the grain size of the $Nd_2Fe_{14}B$ grain is close to 300 nm because they are nucleation-type magnets. In this study, fine particles of Nd-Fe-B are prepared with various grinding energies in the pulverization process used for preparing sintered magnets, and the microstructure and magnetic properties of the magnets are investigated.

• Journal of the Korean Chemical Society
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• v.64 no.5
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• pp.259-266
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• 2020

The main purpose of this study is to examine the different physicochemical properties of spray-dried products. The carrier agents and powders after the spray-drying process were analyzed for encapsulation yield, moisture content, color parameters, total polyphenol content (TPC), antioxidant capacity (AC), bulk density, flowability, wettability, hygroscopicity, water solubility index (WSI), particle size and microstructure. The spray-drying process was carried out with different carrier agents including maltodextrin (MD) and the combination of maltodextrin and gum arabic (MD-GA) with MA/GA ratio of 70/30, dried at the inlet/outlet air temperature of 160 ℃/70 ℃, 4 bar, airflow rate of 70 ㎥·h^-1 and feed flow rate of 750 mL·h^-1. The results showed that the different carrier agents have significant influences on the physicochemical properties of the powder produced by the spray-drying method. In there, while the values of recovery efficiency and flowability of spray-dried products from MD are higher than those of spray-dried products from MD-GA combination, the opposite is true for the values of TPC, AC, bulk density and wettability, whereas hygroscopicity and WSI values are equally represented in both products.

• Environmental Engineering Research
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• v.24 no.1
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• pp.137-143
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• 2019

In this study, extraction, clean-up and instrumental analytical conditions were optimized for identifying and quantifying methyl-, chloromethylbenzi-, octyl- isothiazolinone (MIT, CMIT, BIT, OIT) and 3-iodo-2-propynyl butyl carbamate (IPBC), widely used biocidal active ingredients in human hygiene consumer products. Accuracy of the developed ultrasonic assisted extraction method followed by HPLC/MS analysis for four isothiazolinones and IPBC ranged between 60.4% and 113% in various types of consumer product samples. Method detection limits ranged 0.011-0.034 mg/kg for wet wipes, 0.57-1.5 mg/kg for liquid detergent and 0.58-1.6 mg/kg for powder detergent. Wet wipes, powder and liquid detergents collected from local market in Korea were analyzed to demonstrate the applicability of the developed method. Even after the regulation of those compounds in wet wipes, CMIT, MIT and IPBC were still frequently detected from complementary wet wipes without brand labels which were distributed to customers at local retail shops and restaurants. The maximum observed concentrations of MIT and CMIT found in those complementary wet wipes were 70.2 mg/kg and 11.3 mg/kg, respectively.

• Journal of Powder Materials
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• v.29 no.6
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• pp.499-504
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• 2022

The objective of this study is to assess the impact of spray drying conditions on medium-chain triglyceride (MCT) loading, solubility, and release of an MCT-loaded solid self-emulsifying system in a water-insoluble oily substance. MCT-loaded solid self-emulsifying systems are prepared by spray drying with SDS and calcium silicate. The effects of inlet temperature (60, 80, or 100℃) and feed solution composition (0, 10, 50, 90, or 100% ethanol) on physicochemical properties of MCT-loaded solid self-emulsifying systems are studied. The inlet temperature significantly affects the water solubility of MCT. Moreover, the feed solution composition significantly affects water solubility, release rate, and MCT loading. The MCT-loaded solid self-emulsifying system obtained at 60℃ using 90% ethanol feed solution shows the best physicochemical properties among the synthesized products and exhibits better water solubility (4.43 ± 0.44 vs. 0 ㎍/mL) and release (94.4 ± 1.6 vs. 32.8 ± 7.4%, 60 min) than a commercial product. Furthermore, the MCT-loaded solid self-emulsifying system shows an excellent emulsion droplet size (approximately 230 nm).

• Proceedings of the Korean Institute of Building Construction Conference
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• 2020.11a
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• pp.77-78
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• 2020

An alkaline activator was synthesized by dissolving waste glass powder (WGP) in NaOH-4M solution to explore its effects on the Class-C fly ash (FA) and ground granulated blast furnace slag (GGBS) based alkali-activated material (AAM). The compressive strength and porosity were measured, and (SEM-EDX) were used to study the hydration mechanism and microstructure. Results indicated that the composition of alkali solutions was significant in enhancing the properties of the obtained AAM. As the amount of dissolved WGP increased in alkaline solution, the silicon concentration increased, causing the accelerated reactivity of FA/GGBS to develop Ca-based hydrate gel as the main reaction product in the system, thereby increasing the strength. Further increase in WGP dissolution led to strength loss, which were believed to be due to the excessive water demand of FA/GGBS composites to achieve optimum mixing consistency. Increasing the GGBS proportion in a composite also appeared to improve the strength which contributed to develop C-S-H-type hydration.

• Journal of Applied Biological Chemistry
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• v.49 no.3
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• pp.101-105
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• 2006

Degradation of the herbicide butachlor was investigated using laboratory-synthesized zerovalent iron ($Fe^0$). The synthesized zerovalent iron was determined to be nanoscale powder by scanning electron microscopic analysis. To investigate degradation of butachlor using the synthesized nanoscale zerovalent iron, time-course batch experiments were conducted by treating the solution of butachlor formulation with the iron. More than 90% degradation of butachlor was observed by iron treatment within 24 h. The synthesized nanoscale zerovalent iron showed an increase in particle aggregation in the batch tests. Green rust formation and a pH drop in solutions were observed, suggesting that the oxidation of the iron occurred. When the iron was extracted with dichloromethane, a negligible concentration was found in the extract, suggesting that butachlor did not bind to the iron particles. GC/MS analysis detected the dechlorinated product as a major degradation product of butachlor in the solutions. The data indicate that laboratory-synthesized zerovalent iron functioned as a reductant to remove electron-withdrawing chlorine, giving the dechlorinated product.

• Journal of the Korean Recycled Construction Resources Institute
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• v.8 no.4
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• pp.395-403
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• 2020

CaO-based by-product, which consist of CaO, SO3, Al2O3 and so on, has being used to raw materials of CaO compound. When It was applied to recycling water of remicon, concrete performance can be enhanced because hydration reaction of powder material is accelerated. In this study, activated-sludge, which was putted desulfurization gypsum of CaO-based in recycling water, was manufactured to verify effect of them, and then they was investigated by characteristics of redy-mixde concrete. As a result of concrete tests, it was confirmed that there is no problem of strength or drying shrinkage while ensuring workability. Therefore, the possibility of specific application using activated sludge was confirmed.