• Applied Chemistry for Engineering
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• v.18 no.4
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• pp.320-325
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• 2007

Nickel powders were prepared from an aqueous nickel acetate solution and hydrazine hydrate using diethanolamine as the nonaqueous organic solvent in the conventional and microwave synthetic method. It was investigated that microwave non-thermal effect and synthetic condition affect the preparation of nickel powders by means of X-ray diffractometry, scanning electron microscopy, thermal gravymetry analysis, and X-ray photoelectron spectroscopy analysis. Compared with the conventional synthetic method, less of aggregation, smaller particle size, and more uniform distribution of particle size were obtained in the microwave synthetic method due to the non-thermal effect of microwaves.

• Journal of Korean Society of Water and Wastewater
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• v.19 no.1
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• pp.3-7
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• 2005

In the present study a feasibility of a novel filtration process using synthetic for secondary effluent reclamation was investigated. Polyurethane was chosen as a filter medium among tested three media. Compressibility and up-flow velocity were changed to determine the optimum operation for the system. An equation was introduced to express the relationship between the removal efficiency and up-flow velocity. In pilot study, the synthetic medium filtration with compression showed very stable effluent quality without clogging trouble, though the system operated with 3 times higher filtration rate and much longer backwashing interval than conventional systems.

• Journal of Magnetics
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• v.7 no.4
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• pp.147-150
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• 2002

The pinning direction, the spin flop behaviors and the magnetoresistive properties in top synthetic spin valve structure [NiFe/CoFe/Cu/CoFe (t$_{p2}$)/Ru/CoFe (t$_{p1}$)/IrMn] were investigated. The magnetoresistive and pinning characteristics of synthetic spin valves strongly depended on the differences in the two pinning layer thickness, ${\Delta}t(=t_{p2}-t_{p1})$. In contrast to the conventional spin valves, the pinning direction (P1) was canted off with respect to the growth field axis with ${\Delta}t$. We found that the canting angle ${\Phi}$ had different values according to the annealing field direction and ${\Delta}t$. When the samples were annealed at above the blocking temperature of IrMn with zero fields, the canted pinned layer could be set along the growth field axis. Because the easy axis which was induced by the growth field during deposition is still active in all ferromagnetic layers except the IrMn at $250{^{\circ}C}$, the pinning direction could be aligned along the growth field axis, even in 0 field annealing.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.1
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• pp.29-36
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• 2010

The spectroscopic characteristics of synthetic and natural emeralds were investigated by UV-Vis and FTIR spectroscopy before and after heat treatment. The Mo and Co for synthetic flux and C1 for synthetic hydrothermal emeralds have been detected by X-ray fluorescence analysis. In the region of UV-Visible, the absorption of emerald from Colombia was generally increased after the heat treatment. The peak which related to C1 component in the $3000-2600cm^{-1}$ was shown in the hydrothermal synthetic emeralds by FTIR spectroscopy. The $2358cm^{-1}$ peak which originates from $CO_2$ was decreased after the heat treatment in the natural emerald. This was corresponded with the changes of gas element after heat treatment.

• Biomolecules & Therapeutics
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• v.23 no.6
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• pp.597-603
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• 2015

Synthetic cannabinoids JWH-018 and JWH-250 in 'herbal incense' also called 'spice' were first introduced in many countries. Numerous synthetic cannabinoids with similar chemical structures emerged simultaneously and suddenly. Currently there are not sufficient data on their adverse effects including neurotoxicity. There are only anecdotal reports that suggest their toxicity. In the present study, we evaluated the neurotoxicity of two synthetic cannabinoids (JWH-081 and JWH-210) through observation of various behavioral changes and analysis of histopathological changes using experimental mice with various doses (0.1, 1, 5 mg/kg). In functional observation battery (FOB) test, animals treated with 5 mg/kg of JWH-081 or JWH-210 showed traction and tremor. Their locomotor activities and rotarod retention time were significantly (p<0.05) decreased. However, no significant change was observed in learning or memory function. In histopathological analysis, neural cells of the animals treated with the high dose (5 mg/kg) of JWH-081 or JWH-210 showed distorted nuclei and nucleus membranes in the core shell of nucleus accumbens, suggesting neurotoxicity. Our results suggest that JWH-081 and JWH-210 may be neurotoxic substances through changing neuronal cell damages, especially in the core shell part of nucleus accumbens. To confirm our findings, further studies are needed in the future.

• Communications of Mathematical Education
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• v.28 no.1
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• pp.97-130
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• 2014

The purpose of the study was to investigate the aspects of analogy of high school student's thinking process revealed in the inquiry activity with synthetic division. The case study method of qualitative research was conducted with two high school 10th grade students. Structure-mapping model(SMM) of Gentner and similarity frames which were proposed by other researchers were utilized to analyze the data. Two students used analogy as a tool and they could discover synthetic division of more than 2 degrees, but they revealed different levels of mathematics discovery depending on the different degree of analogical thinking. Surface similarity in the process of inquiry activity played a vital role in analogical thinking. We asked students to explore and discover analogy based on structure similarity. Analogy based on the systematic approach made it possible to predict upper domain. Analogy based on the procedure similarity induced internalization. We could conclude that analogy has instrumental, heuristic and reflective characteristics.

• Transactions of the Korean hydrogen and new energy society
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• v.28 no.5
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• pp.561-569
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• 2017

In this study, a synthetic amine made using the ethylene oxide-ammonia reaction was used as an absorbent to remove carbon dioxide. Existing absorbents were used in a mix in order to improve performance; however, because the ethylene oxide-ammonia reaction generates primary, secondary, and tertiary amines simultaneously, it has the merit that separate mixing of the absorbents was not needed. The performance of carbon dioxide absorption with the synthetic amine was compared to that of MEA. As a result of an experiment, it was determined that the $CO_2$ loading was 1.15 times better than that of MEA (a commonly used amine), while the cyclic capacity was 2.28 times higher. Because the heat of reaction was 1.10 times lower than for MEA, the synthetic amine showed superior performance in terms of absorption and regeneration.

• Proceedings of the Korean Magnestics Society Conference
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• 2003.12a
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• pp.80-80
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• 2003

• KIEE International Transactions on Electrophysics and Applications
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• v.5C no.4
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• pp.145-151
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• 2005

The synthetic breaking test method was developed to evaluate the breaking performance of ultra high-voltage circuit breaker and made up of two independent circuits; current source circuit and voltage source circuit. In application of this test method, it is necessary to extend the arc of the test breaker. So, the new re-ignition system using VTGS (Vacuum Triggered Gap-Switch) was constructed to improve the efficiency and reliability of this test. In this re-ignition system, VTGS operates in high vacuum state of $5{\time}10^{17}$torr and control system consists of the triggering device and the air M-G (Motor-Generator). This re-ignition system showed the operating characteristics, such as delay time ($t_d$) and jitter time ($t_j$ not exceeding 5us and 1us respectively, and had the operating voltage of $25\~150kVdc$ at the gap distance of 24mm.

• The Korea Journal of Herbology
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• v.33 no.6
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• pp.9-18
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• 2018

Objective : Many patients take antihypertensive drugs as well as herbal medicines at the same time in order to treat other symptoms or to keep their well-being. In this study, interactions between herbal medicines and synthetic antihypertensive drugs were analyzed. Methods : To investigate the interaction between herbal medicines and synthetic antihypertensive drugs, three electronic databases, including OASIS, Mediline and Sciencedirect were searched. Experimental and clinical studies on the interaction between herbal medicines and antihypertensive drugs were independently reviewed and included. Results : Analyzing selected studies, twenty herbs were found to interact with antihypertensive drugs. Herbs found to increase the antihypertensive effect were Panax ginseng, Carthamus tinctorius, Magnolia officinalis, Silybum marianum, Scutellaria baicalensis, Schisandra chinensis, Sophora flavescens, Piper nigrum, Curcuma longa, Ginkgo biloba, Juncus effuses and Hydrastis canadensis. In contrast, Commiphora myrrha, Rhodiola rosea, Hypericum perforatum, Eurycoma longifolia, and Daturae metel were found to inhibit the antihypertensive effect. Stephania tetrandra could increase or decrease the effect depending on the type of antihypertensive drug. Epedria sínica was suspected of pharmacodynamic interaction with antihypertensive drug. Glycyrrhiza uralensis has been reported to have serious side effects in combination with antihypertensive drugs. Conclusion : These results imply that when used in combination with herbal medicines and synthetic antihypertensive drugs, proper doses and herbs which are to avoid need to be informed to the patients. Despite concerns about interactions between herbal medicines and synthetic drugs, related research is very limited. More systematic researches are needed to give information on patient safety as well as to guide clinical practice.