• Resources Recycling
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• v.30 no.5
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• pp.25-31
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• 2021

Smelting reduction of spent lithium-ion batteries results in the production of metallic alloys in which reduced cobalt, nickel and copper coexist. In this study, we investigated the leaching of the metallic alloys containing the above three metals together with iron, manganese, and silicon. The mixture of hydrochloric acid and hydrogen peroxide as an oxidizing agent was employed, and the effect of the concentration thereof, the reaction time and temperature, and pulp density was investigated to accomplish the complete leaching of cobalt, nickel, and copper. The effect of the hydrogen peroxide concentration and pulp density on the leaching was prominent, compared to that of reaction time and temperature, especially in the range of 20 to 80℃. The complete leaching of the metals present in metallic alloys, except silicon, was accomplished using 2 M HCl and 5% H₂O₂ with a pulp density of 30 g/L for 150 min at 60℃.

• Korean Journal of Metals and Materials
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• v.47 no.8
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• pp.488-493
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• 2009

Direct syntheses of bulk $Ti_3Al$ via electro-discharge-sintering (EDS) of a stoichiometric elemental powder mixture were investigated. A capacitor bank of $450{\mu}F$ was charged with three input energies, 0.5, 1.0, and 1.5 kJ. The charged capacitor bank was then instantaneously discharged through 0.3 g of a Ti-25.0 at.%Al powder mixture for consolidation. Complete phase transformation occurred in less than $200{\mu}sec$ by the discharge and a bulk $Ti_3Al$ compact was obtained. Compared with consolidated samples fabricated by conventional methods such as high vacuum sintering and casting, the electro-discharge-sintered $Ti_3Al$ compact shows a very fine microstructure with a hardness value of 425 Hv. Electro-discharge-sintering under a $N_2$ atmosphere successfully modified the surface Ti oxide of the $Ti_3Al$ compact into Ti nitride, which concurred with the synthesis and consolidation of $Ti_3Al$. Complete conversion yielding a single phase $Ti_3Al$ is primarily dominated by the fast solid state diffusion reaction.

• The Journal of Internal Korean Medicine
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• v.31 no.1
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• pp.11-24
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• 2010

Objectives : This study was carried out to investigate the hepatoprotective effects of mixture with Hovenia dulcis Thunb (HDT) and Acer tegmentosum Maxim(ATM) on D-galactosamine-induced liver failure in rats. Methods : The animals were divided into 4 groups: control, with liver failure and no treatment; H1A1, with liver failure and oral treatment with HDT 1 and ATM 1; H1A2, with liver failure and oral treatment with HDT 1 and ATM 2; H1A4, with liver failure and oral treatment with HDT 1 and ATM 4. The animals were treated for 3 weeks and then examinations of change of body weight, aspartate aminotransferase (AST), alanine aminotransferase (ALT), gamma glutamyl transpeptidase ($\gamma$-GTP), total cholesterol, triglyceride, total bilirubin, superoxide dismutase (SOD), catalase, histopathologic change, and complete blood count (CBC) were performed. Results : All experimental groups had significantly decreased AST in serum and markedly increased activity of SOD as compared with the control group. H1A1, and H1A4 significantly decreased ALT in serum and H1A4 at 2 weeks was significantly higher on the change of body weight as compared with the control group. In histopathologic change of liver tissue by light microscopy, all experimental groups showed recovery effects of liver cells which were damaged by D-galactosamine. Conclusions : Based upon these results, it could be assumed that a mixture of HDT and ATM has hepatoprotective and antioxidative effects on D-galactosamine-induced liver failure. Therefore, a mixture of HDT and ATM might be utilized as a protective agent in therapy for liver diseases.

• Resources Recycling
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• v.25 no.1
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• pp.16-23
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• 2016

The separation behaviour of Mo and W from sulfuric acid solution by solvent extraction with Alamine 336 was investigated as a function of solution pH and extractant concentration. Selective extraction of Mo over W by Alamine 336 was obtained in the pH range of 3-5 with low amine concentration. The mixture of Alamine 336 and acidic extractants improved the separation factor between Mo and W and was in the following order: D2EPHA > PC88A > Decanol > Versatic acid. The stripping efficiency of Mo and W from the loaded mixture of Alamine 336 and D2EHPA was very poor, while complete stripping of Mo and W was possible from the mixture of Alamine 336 and Decanol by using a mixture of $NH_4OH$ and $NH_4Cl$.

• The Journal of the Korean Society for Microbiology
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• v.6 no.1
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• pp.15-20
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• 1971

A vaccine was prepared by $10^6$ r cobalt-60 irradiation of lyophilized virulent Brucella melitensis and tested in mice for immunogenic activity against a lethal challenge dose of the homologous strain. The vaccine(GIV) produced a high degree of immunity in mice, and comparative studies demonstrated it to be superior to vaccines prepared by heat or by chemical(ether, formalin, or phenol) treatment. Living vaccines, Brucella abortus. strain 19 and an R-form of Brucella melitensis were lethal for mice in larger doses. A comparison of seven adjuvant mixtures for use with the GIV showed no statistically significant difference, but. Freund's complete adjuvant and a mixture of aluminum-potassium sulfate and pectin appeared to enhance the activity of the GIV.

• Journal of Korean Society on Water Environment
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• v.24 no.1
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• pp.118-122
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• 2008

Degradations of phenol and chlorinated compounds mixtures were studied with ultrasound of 20 kHz and 0.57, 1.14 W/mL. In presence of carbon tetrachloride (CT), degradation rate of phenol is faster than chloroform (CF), dichloromethane (DCM) and phenol solution. It is due to that CT generates of free chlorine (HOCl and $OCl^-$) from the sonochemical degradation and plays a role of hydrogen atom scavenger. CF and DCM are react with free chlorine, so amount of free chlorine is smaller than CT solution. The degradation rates of chlorinated compounds decreased with co-presence of phenol in the solution due to the distribution ultrasonic energy to both compounds. The measured chloride ion was lower than the theoretical concentration assuming complete degradation. This means not all the contaminants destructed went through complete degradation.

• Applied Biological Chemistry
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• v.39 no.4
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• pp.309-314
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• 1996

2-Furyltriisopropoxytitanium was synthesized in situ through transmetallation of 2-furyllithium with chlorotitaniumtriisopropoxide. The compound could be isolated at room temperature and preserved at $-10^{\circ}C$ for several weeks. The reactivity 2-furyltriisopropoxytitanium to carbonyl compounds proved to be high. A complete aldehyde selectivity was observed in competition reactions of 2-furyltriisopropoxytitanium with a 1:1 mixture of aldehyde and ketone. In competition reactions of 2-furyltriisopropoxytitanium with a 1 : 1 mixture of ketone and ketone, the degree of ketone / ketone discrimination was substantial. In the reaction of 2-furyltriisopropoxytitanium to ketone-ester function, the reagent was solely reacted with the ketone function.

• International Journal of Concrete Structures and Materials
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• v.11 no.2
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• pp.391-401
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• 2017

In this study, the effects of water-to-binder (W/B) ratio and replacement ratio of blast furnace slag (BFS) on the compressive strength of concrete were first investigated to determine an optimized mixture. Then, using the optimized high-strength concrete (HSC) mixture, hooked steel fibers with various aspect ratios and volume fractions were used as additives and the resulting mechanical properties under compression and flexure were evaluated. Test results indicated that replacement ratios of BFS from 50 to 60% were optimal in maximizing the compressive strength of steam-cured HSCs with various W/B ratios. The use of hooked steel fibers with the aspect ratio of 80 led to better mechanical performance under both compression and flexure than those with the aspect ratio of 65. By increasing the fiber aspect ratio from 65 to 80, the hooked steel fiber volume content could be reduced by 0.25% without any significant deterioration of energy absorption capacity. Lastly, complete material models of steel-fiber-reinforced HSCs were proposed for structural design from Lee's model and the RILEM TC 162-TDF recommendations.

• Restorative Dentistry and Endodontics
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• v.43 no.2
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• pp.17.1-17.7
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• 2018

Iatrogenic perforations negatively impact the outcome of endodontic treatments. Studies on prognostic factors showed that perforations in the coronal third of the root with periodontal pocket formation have an unfavorable prognosis. A 36-year-old female was referred for endodontic evaluation of tooth #13 with a history of an iatrogenic perforation, happened 3 years ago. There was a sinus tract associated with perforation, 10 mm probing on the mesial and mesio-palatal, bleeding on probing, radiolucent lesion adjacent to the perforation and complete resorption of the interdental bone between teeth #13 and #12. After the treatment options were discussed, she chose to save the tooth. The tooth was accessed under rubber dam isolation, the perforation site was cleaned and disinfected using 0.5% sodium hypochlorite and sealed with calcium-enriched mixture cement. Eighteen months after treatment the tooth was functional and asymptomatic. The probing depths were normal without bleeding on probing. Radiographically, the interdental crestal bone formed between teeth #13 and #12. Despite all negative prognostic factors in this case (i.e., perforations in the coronal third, pocket formation, and radiolucent lesion), healing was unexpectedly achieved via non-surgical repair of the perforation. Further research on biological aspects of healing in the periodontium following iatrogenic perforations are recommended.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.55 no.2
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• pp.57-61
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• 2006

This paper calculates and gives the analysis of mean energy in pure $SiH_4,\;Ar-SiH_4$ mixture gases ($SiH_4-0.5[%],\;5[%]$) over the range of $E/N =0.01{\sim}300[Td]$, p = 0.1, 1, 5.0 [Torr] by Monte Carlo the Backward prolongation method of the Boltzmann equation using computer simulation without using expensive equipment. The results have been obtained by using the electron collision cross sections by TOF, PT, SST sampling, compared with the experimental data determined by the other author. It also proved the reliability of the electron collision cross sections and shows the practical values of computer simulation. The calculations of electron swarm parameters require the knowledge of several collision cross-sections of electron beam. Thus, published momentum transfer, ionization, vibration, attachment, electronic excitation, and dissociation cross-sections of electrons for $SiH_4$ and Ar, were used. The differences of the transport coefficients of electrons in $SiH_4$, mixtures of $SiH_4$ and Ar, have been explained by the deduced energy distribution functions for electrons and the complete collision cross-sections for electrons. A two-term approximation of the Boltzmann equation analysis and Monte Carlo simulation have been used to study electron transport coefficients.