• Bulletin of the Korean Chemical Society
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• 제22권1호
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• pp.43-45
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• 2001

This study simplifies the phenomenological theory of viscosity previously proposed by the present authors. This simplified theory has only two thermodynamic properties and one parameter, as opposed to its predecessor, which has many, allowing for easy calculation of the liquid viscosities. The viscosity of liquid metals, an excellent test for checking the validity of the liquid theory, can be calculated using the equation based on the simplified theory. The calculated results by the current theory turn out to be good for the liquid metals, including sodium, potassium, rubbidium, cesium, lead and mercury.

• 전기화학회지
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• 제15권3호
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• pp.135-148
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• 2012

Ionic liquids are steadily attracting interests throughout a recent decade and their application is expanding into various fields including electrochemistry due to their unique properties such as non-volatility, inflammability, low toxicity, good ionic conductivity, wide electrochemical potential window and so on. These features make ionic liquids become an alternative solution for electrodeposition of metals that cannot be electroplated in aqueous electrolytes. In this review, we classify investigated metals into three categories, which are light (Li, Mg), refractory (Ti, Ta) and noble (Pd, Pt, Au) metals, rather than covering the exhaustive list of metals and try to update the recent development in this area. In electrodeposition of light metals, granular fine Li particles were successfully obtained while the passivation of electrodeposited Mg layers is an obstacle to reversible deposition-dissolution process of Mg. In the case of refractory metals, the quality of Ta and Ti deposit particles was effectively improved with addition of LiF and pyrrole, respectively. In noble metal category, EMIM TFSA ionic liquid as an electrolyte for Au electrodeposition was proven to be effective and BMP TFSA ionic liquid developed a smooth Pd deposit. Pt nanoparticle production from ionic liquid droplet in aqueous solution can be cost-effective and display an excellent electrocatalytic activity.

• Bulletin of the Korean Chemical Society
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• 제11권5호
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• pp.446-449
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• 1990

A phenomenological theory of viscosity which has been proposed by authors is applied to liquid metals for which the calculation is a severe test for liquid theories. The thermodynamic properties used in the calculations can be obtained by using the Roulette liquid theory. The calculated values of the viscosities for liquid metals are in good agreements with the observed values.

• Nuclear Engineering and Technology
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• 제49권1호
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• pp.82-91
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• 2017

Liquid alloy systems have a high degree of thermal conductivity, far superior to ordinary nonmetallic liquids and inherent high densities and electrical conductivities. This results in the use of these materials for specific heat conducting and dissipation applications for the nuclear and space sectors. Uniquely, they can be used to conduct heat and electricity between nonmetallic and metallic surfaces. The motion of liquid metals in strong magnetic fields generally induces electric currents, which, while interacting with the magnetic field, produce electromagnetic forces. Electromagnetic pumps exploit the fact that liquid metals are conducting fluids capable of carrying currents, which is a source of electromagnetic fields useful for pumping and diagnostics. The coupling between the electromagnetics and thermo-fluid mechanical phenomena and the determination of its geometry and electrical configuration, gives rise to complex engineering magnetohydrodynamics problems. The development of tools to model, characterize, design, and build liquid metal thermomagnetic systems for space, nuclear, and industrial applications are of primordial importance and represent a cross-cutting technology that can provide unique design and development capabilities as well as a better understanding of the physics behind the magneto-hydrodynamics of liquid metals. First studies for the development of computational tools for the design of liquid metal electromagnetic pumps are discussed.

• Archives of Metallurgy and Materials
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• 제65권4호
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• pp.1281-1285
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• 2020

Recently, since the demand of rare earth permanent magnet for high temperature applications such as an electric motor has increased, dysprosium (Dy), a heavy rare earth element, is becoming important due to severe bias in its production. To fulfill the increasing need of Dy, recycling offers as a promising alternative. In recycling of rare earths, Hydro-metallurgical extraction method is mainly used however it has adverse environmental effects. Liquid metal extraction on the other hand, is an eco-friendly and simple method as far as the reduction of rare earth metal oxide is concerned. Therefore, liquid metal extraction was studied in this research as an alternative to the hydro-metallurgical recycling method. Magnesium (Mg) is selected as solvent metal because it doesn't form intermetallic compounds with Fe, B and has a low melting and low boiling point. Extraction behavior of Dy in (Nd,Dy)-Fe-B magnet is observed and effect of Mg ratio on extraction of Dy is confirmed.

• Journal of Welding and Joining
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• 제18권5호
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• pp.90-97
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• 2000

Effect of alloy elements on joinability of insert metal for liquid phase diffusion bonding of heat resistant alloys was investigated in this study. Also, optimum chemical composition of insert metal was explained using interpolation method. The insert metals utilized was commercial Ni-base amorphous foils and newly developed Ni-base filler metals with B, Si and Cr in this study. Melting point and critical interlayer width(CIW) decreased with increasing additional amount of B, Si and Cr, melting point lowering element of the insert metal. Optimized chemical composition of insert metals could be estimated by interpolation method. The optimum amount of B, Si, Cr addition into the insert metal were found to be about 3%, 4% and 3%, respectively. The measured characteristic values, melting point, microhardness in the bonded interlayer and CIW of the insert metals were the almost identical to ones of the calculated results by interpolation method.

• 산업기술연구
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• 제43권1호
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• pp.25-31
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• 2023

Stretchable and flexible electronics that comply with dynamic movements and micromotion of the human tissues can enable real-time monitoring of physiologic signals onto the human skin and in the brain, respectively. Especially, gallium based liquid metal stretchable electronics can offer human-interactive biosensors to monitor various physiologic parameters. However, the liquid-like nature, surface oxidation and contamination by organic materials, and low biostability of the liquid metals have still limited the long-term use as bioelectronics. Here we introduced electrochemical deposition without oxidation pathways to overcome these practical challenges in liquid metal bioelectronics. CNT/PDDA composite with reduction way and PEDOT:BF₄ with oxidation way under organic solvent are suggested as rationally designed material engineering approaches. We confirmed that the structures with the soft, flexible, and stretchable liquid metal platform can successfully detect dopamine with a high sensitivity and selectivity, record neural signals including action potentials without scar formation, and monitor physiologic signals such as EMG and ECG.

• Bulletin of the Korean Chemical Society
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• 제33권5호
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• pp.1509-1516
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• 2012

Nano-assisted inclusion separation of alkali metals from basic solutions was reported by inclusion-facilitated emulsion liquid membrane process. The novelty of this study is application of nano-baskets of calixarene in the selective and efficient separation of alkali metals as both the carrier and the surfactant. For this aim, four derivatives of $p-tert-calix$[4]arene bearing different sulfonamide moieties were synthesized and their inclusion-extraction parameters were optimized including the calixarene scaffold $\mathbf{3}$ (4 wt %) as the carrier/demulsifier, the commercial kerosene as diluent in membrane, sulphonic acid (0.2 M) and ammonium carbonate (0.4 M) as the strip and the feed phases, the phase and the treat ratios of 0.8 and 0.3, mixing speed (300 rpm), and initial solute concentration (100 mg/L). The selectivity of membrane over more than ten interfering cations was examined and the results reveled that under the optimized operating condition, the degree of inclusion-extraction of alkali metals was as high as 98-99%.

• 한국환경과학회지
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• 제17권1호
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• pp.129-133
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• 2008

This study is an endeavor to evaluate the safety of medicines from heavy metals, prescribed on the basis of herbal medicinal system and oriental medical prescription which are circulated much recently. For that, three globular types, four extract granular types and four liquid types of herbal medicine were bought to compare and analyze the content of heavy metals, such as As, Pb, Cd and Hg, which are harmful to human body. The concentration of Pb was found to be 0.552 ppm in Sachiltang, 2.552 ppm in Anjungjogiwhan and 1.735 ppm in Cheongsangbohwawhan in case of pill type herbal medicine, and liquid type herbal medicine, Maekmundongtang was 0.002 ppm, Galgeuntang was 0.003 ppm, Sangwhatang was 0.004 ppm, 20jeon Daebotang was 0.0185 ppm. And the concentration of Pb was found to be 0.322 ppm in Banhasasimtang, 0.47 ppm in Eungjosan, 0.29 ppm in Yukmijihwangtang, 0.64 ppm in Socheongryongtang in case of granular type. It was found that the liquid types herbal medicines were relatively safer than three pill types of, four granular types of and four liquid types herbal medicines were tested for concentration of heavy metals. It is considered that is required in the stage of raw material treatment, manufacturing and packaging because those herbal medicines are directly taken in and absorbed into human body through the final treatment process.

• KSBB Journal
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• 제25권1호
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• pp.91-96
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• 2010

This study is an endeavor to evaluate the safety of medicines from heavy metals, prescribed on the basis of herbal medicinal system and oriental medical prescription which are circulated much recently. For that, six globular types, six granular types and seven liquid types of herbal medicines were bought to compare and analyze the content of heavy metals, such as As, Pb, Cd and Hg, which are harmful to human body. The concentration of As was 0.219 mg/kg to 1.243 mg/kg, Cd was 0.0282 mg/kg to 0.8481 mg/kg, Pb was 0.9582 mg/kg to 5.233 mg/kg and Hg was 0.001 mg/kg to 0.01 mg/kg in globular and granular types. Otherwise, in the liquid types, As was 0.0123 mg/kg to 0.5024 mg/kg, Cd was 0.0128 mg/kg to 0.0568 mg/kg, Pb was 0.1755 mg/kg to 0.712 mg/kg, and Hg was 0.001 mg/kg to 0.002 mg/kg. It was found that the concentration of heavy metals in liquid types herbal medicines was relatively lower than globular and granular types. It is required to treat, manufacture and manage herbal medicines for safety.