• Proceedings of the Korean Institute of Building Construction Conference
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• 2011.05b
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• pp.59-60
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• 2011

This study is investigated reduced heat hydration and fresh and hardened concrete of high strength concrete by hydration heat reducing agent that is type of alcohol, paraffin wax micro-capsules, and strontium.

• Proceedings of the Korean Ceranic Society Conference
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• 2003.04a
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• pp.135.2-135
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• 2003

• Proceedings of the Korean Magnestics Society Conference
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• 2013.12a
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• pp.52-52
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• 2013

• Proceedings of the Materials Research Society of Korea Conference
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• 1998.08a
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• pp.132.3-132
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• 1998

• 한국신재생에너지학회:학술대회논문집
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• 2010.11a
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• pp.89.2-89.2
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• 2010

고체산화물 연료전지는 $800{\sim}1000^{\circ}C$인 고온에서 작동하므로 적용되는 밀봉재의 요구조건은 매우 중요하다. 본 연구에서는 SOFC 밀봉재로서 $SiO_2-B_2O_3-RO$계 결정화 유리를 선정하였으며 작동온도 부근에서 결정화를 유도하여 고온점성유동을 제어하고자 하였다. 따라서 $SiO_2-B_2O_3-RO$계에 RO인 CaO, SrO, BaO, MgO를 상호 치환하였을 때 결정상의 생성, 생성온도, 생성결정의 종류가 sealing 특성에 어떠한 영향을 주는가를 검토하였다. 결정화유리를 $800^{\circ}C$로 유지하였을 때 생성되는 주 결정상은 Calsium silicate, Strontium silicate, Barium silicate, Magnesium silicate이였으며 Strontium silicate 의 생성속도가 가장 빨랐으며 결정상은 불산으로 에칭하여 SEM으로 관찰하였다. Barium silicate를 유도한 결정화 유리가 $800^{\circ}C$에서 1000시간 유지하였을 경우 가장 내화학성이 우수하며 강도값도 154MPa로 가장 높았다. 또한 부분 결정화를 통해 $800^{\circ}C$ 점성유동이 제어됨을 고온현미경을 통해 관찰하였다.

• Journal of Microbiology and Biotechnology
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• v.7 no.4
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• pp.250-257
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• 1997

A new sensing system based on the immobilization of luminescent bacteria, photobacterium phosphoreum, was proposed for continuous real-time monitoring of pollutants. The response curves demonstrate that Photobacterium phosphoreum immobilized on the strontium alginate were very sensitive to seven reference chemicals used. The significant inhibitory concentrations for bioluminescence emission were 5 ppm for Pb$(NO_3)_2$), $NiCl_2$, $CdCl_2$, 50 ppm for $NaASO_2$, 0.1 ppm for $HgCl_2$, 0.5 ppm for pentachlorophenol and less than 5 ppm for SDS, respectively. The alginate mixed-cells (AMC) retained their luminescence during experimental period (29 days) under storage condition of $-80^{\circ}C$. The variables affecting performance of continuous flow through monitoring (CFTM) was optimized in order to ensure stability and efficiency. The flow through cell with strontium-alginate immobilized luminescent bacteria was tested with salicylate and 4-nitrophenol. A rapid response of luminescence was recorded by time drive mode in bioluminescence spectrometer after exposure to both toxicants.

• Advances in environmental research
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• v.6 no.4
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• pp.301-315
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• 2017

An Amberlite XAD-4 resin impregnated with di(2-ethylhexyl)phosphoric acid was prepared and its adsorption-desorption behaviors with Sr(II) ions under various conditions was examined. The resin was characterized by fourier transform infrared and thermal analysis techniques. The effects contact time, temperature, pH, interfering ions and eluants were studied. Results showed that adsorption of Sr (II) well fitted with pseudo-second-order kinetic model. The equilibrium adsorption data of Sr (II) on the impregnated resin were analyzed by Jossens, Weber-van Vliet, Redlich-Peterson and Fritz-Schlunder models to find out desirable equilibrium condition. Among them, the Fritz-Schlunder model best fitted to the experimental data. The maximum sorption capacity of impregnated resin amounted to 0.45 mg/ g at pH 8.0 and $20^{\circ}C$.

• Safety and Health at Work
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• v.4 no.4
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• pp.216-220
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• 2013

A 46-year-old man who had worked as a bumper spray painter in an automobile body shop for 15 years developed lung cancer. The patient was a nonsmoker with no family history of lung cancer. To determine whether the cancer was related to his work environment, we assessed the level of exposure to carcinogens during spray painting, sanding, and heat treatment. The results showed that spray painting with yellow paint increased the concentration of hexavalent chromium in the air to as much as $118.33{\mu}g/m^3$. Analysis of the paint bulk materials showed that hexavalent chromium was mostly found in the form of lead chromate. Interestingly, strontium chromate was also detected, and the concentration of strontium chromate increased in line with the brightness of the yellow color. Some paints contained about 1% crystalline silica in the form of quartz.

• Electrical & Electronic Materials
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• v.8 no.3
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• pp.324-331
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• 1995

0.36[wt%l $SiO_{2}$ and 0.1[wt%] $H_{3}$B $O_{3}$ were added to strontium ferrite magnets of the magnetoplumbite phase SrO.5.7F $e_{2}$ $O_{3}$ to hinder grain growth and accelerate sintering, respectively. This experiment was carried out to investigate effect of particle size distribution as a function of milling time(20, 30, 40, 50, 60, 70 hours) on the magnetic properties of SrO.5.7F $e_{2}$ $O_{3}$ ferrite magnet. The B-H curve, density and the degree of orientation were measured. And the microstructure of ferrite magnets was examined with a SEM. The optimal conditions and properties of the typical sample are the following : The milling time was 60 hours. Magnetic and physical properties are $B_{r}$=4, 000[G], $_{b}$ $H_{c}$=3, 330[Oe], (BH)max=3.786[MGOe], $_{I}$ $H_{c}$=3, 525[Oe], density=5.0063[g/c $m^{3}$] and orientation factor f=0.813.0.813.3.3.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.31A no.7
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• pp.63-68
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• 1994

The Curie point annealing effects on electrophysical phenomena at the magnetized strontium ferrite(SrO$\cdot$ 6$Fe_{2}O_{3}$) ceramics electrode/10$^{-3}$M KC1 aqueous electrolyte interfaces have been studied using cyclic voltammetric, normal pulse voltammetric, chronocoulometric, and electrochemical impedance techiques. After the Curie point annealing the magnetic flux densities of the speciment was decreased from 900-1100 gauss to 1-2 gauss, i.e. demagnetized. The real component of interfacial impedance was decreased from 7280-7320 ohm to 790-830 ohm. The adsorption and the charge on the electrical double layer was increased from 0 $\mu$C to -58 $\mu$C. The Curie point annealing and the related electrical double layer effect can influence not only the electrophysical properties of the strontium ferrite ceramics electrode itself but also the electrochemical phenomena at the electrode interface. This experimental results suggest that the Curie point annealing and the related electrical double layer effect can be applied to electrochemical magnetic sensors.