• Korean Chemical Engineering Research
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• v.55 no.6
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• pp.854-860
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• 2017

PSf/D2EHPA/CNTs beads were prepared by immobilizing extractant di-(2-ethylhexyl)- phosphoric acid (D2EHPA) and adsorbent carbon nanotubes (CNTs) on polysulfone (PSf), and the adsorption characteristics of Sr(II) on the beads were studied. The morphological characteristics of the prepared PSf/D2EHPA/CNTs beads were observed by scanning electron microscopy (SEM), thermo gravimetric analysis (TGA), and Fourier transform infrared spectrometer (FTIR). The equilibrium time for the removal of Sr(II) by PSf/D2EHPA/CNTs beads was 60 min. The experimental kinetic data followed pseudo-second-order model more than pseudo-first-order kinetics model. The maximum removal capacity of Sr(II) obtained from Langmuir isotherm was 4.75 mg/g. The removal efficiencies of Sr (II) by PSf/D2EHPA/CNTs beads were improved 2.5 times by adding the adsorbent CNTs more than by using only the extractant D2EHPA.

• Applied Chemistry for Engineering
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• v.29 no.3
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• pp.264-269
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• 2018

PSf/D2EHPA/TBP/CNTs beads were prepared by immobilizing carbon nanotubes (CNTs) and two extractants, di-(2-ethylhexyl)-phosphoric acid (D2EHPA) and tributyl phosphate (TBP) on polysulfone (PSf). The prepared PSf/D2EHPA/TBP/CNTs beads were characterized by SEM, TGA, and FTIR. The removal rate of Sr(II) by PSf/D2EHPA/TBP/CNTs beads was well described by the pseudo-second-order kinetic model. The maximum removal capacity of Sr(II) obtained from Langmuir isotherm was found to be 5.52 mg/g. The results showed that the removal efficiency of Sr(II) by PSf/D2EHPA/CNTs beads prepared in this study was significantly improved compared to that of using PSf/D2EHPA/CNTs beads without TBP.

• Korean Journal of Agricultural Science
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• v.46 no.2
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• pp.257-271
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• 2019

The use of food grade hexane (FGH) for edible oil extraction is responsible for the presence of benzene in the crude oil. Benzene is a Group 1 carcinogen and could pose a serious threat to the health of consumer. However, its detection still depends on classical methods using chromatography which requires a rapid non-destructive detection method. Hence, the aim of this study was to investigate the feasibility of using Fourier transform infrared (FTIR) spectroscopy combined with multivariate analysis to detect and quantify the benzene residue in edible oil (sesame and cottonseed oil). Oil samples were adulterated with varying quantities of benzene, and their FTIR spectra were acquired with an attenuated total reflectance (ATR) method. Optimal variables for a partial least-squares regression (PLSR) model were selected using the variable importance in projection (VIP) and the selectivity ratio (SR) methods. The developed PLS models with whole variables and the VIP- and SR-selected variables were validated against an independent data set which resulted in $R^2$ values of 0.95, 0.96, and 0.95 and standard error of prediction (SEP) values of 38.5, 33.7, and 41.7 mg/L, respectively. The proposed technique of FTIR combined with multivariate analysis and variable selection methods can detect benzene residuals in edible oils with the advantages of being fast and simple and thus, can replace the conventional methods used for the same purpose.

• Advances in environmental research
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• v.9 no.3
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• pp.215-232
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• 2020

Crude oils are essential source of energy. It is majorly found in geographical locations beneath the earth's surface and crude oil is the main factor for the economic developments in the world. Natural crude oil contains unrefined petroleum composed of hydrocarbons of various molecular weights and it contains other organic materials like aromatic compounds, sulphur compounds, and many other organic compounds. These hydrocarbons are rapidly getting degraded by biosurfactant producing microorganisms. The present study deals with the isolation, purification, and characterization of biosurfactant producing microorganism from oil-contaminated soil. The ability of the microorganism producing biosurfactant was investigated by well diffusion method, drop collapse test, emulsification test, oil displacement activity, and blue agar plate method. The isolate obtained from the oil contaminated soil was identified as Bacillus subtilis. The identification was done by microscopic examinations and further characterization was done by Biochemical tests and 16SrRNA gene sequencing. Purification of the biosurfactant was performed by simple liquid-liquid extraction, and characterization of extracted biosurfactants was done using Fourier transform infrared spectroscopy (FTIR). The degradation of crude oil upon treatment with the partially purified biosurfactant was analyzed by FTIR spectroscopy and Gas-chromatography mass spectroscopy (GC-MS).

• The Plant Pathology Journal
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• v.38 no.3
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• pp.212-219
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• 2022

Fusarium root rot caused by the soil-borne fungus Fusarium solani is one of the most important fungal diseases of cassava in Thailand, resulting in high yield losses of more than 80%. This study aimed to investigate if the exogenous application of salicylic acid formulations (Zacha) can induce resistance in cassava against Fusarium root rot and observe the biochemical changes in induced cassava leaf tissues through synchrotron radiation based on Fourier-transform infrared (SR-FTIR) microspectroscopy. We demonstrated that the application of Zacha11 prototype formulations could induce resistance against Fusarium root rot in cassava. The in vitro experimental results showed that Zacha11 prototype formulations inhibited the growth of F. solani at approximately 34.83%. Furthermore, a significant reduction in the disease severity of Fusarium root rot disease at 60 days after challenge inoculation was observed in cassava plants treated with Zacha11 at a concentration of 500 ppm (9.0%). Population densities of F. solani were determined at 7 days after inoculation. Treatment of the Zacha11 at a concentration of 500 ppm resulted in reduced populations compared with the distilled water control and differences among treatment means at each assay date. Moreover, the SR-FTIR spectral changes of Zacha11-treated epidermal tissues of leaves had higher integral areas of lipids, lignins, and pectins (1,770-1,700/cm), amide I (1,700-1,600/cm), amide II (1,600-1,500/cm), hemicellulose, lignin (1,300-1,200/cm), and cellulose (1,155/cm). Therefore, alteration in defensive carbohydrates, lipids, and proteins contributed to generate barriers against Fusarium invasion in cassava roots, leading to lower the root rot disease severity.

• Journal of Environmental Science International
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• v.24 no.9
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• pp.1145-1153
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• 2015

PVC-Zeolite composite was prepared by immobilizing zeolite with polyvinyl chloride (PVC). The prepared PVC-Zeolite beads were characterized by using X-ray diffractometer (XRD), fourier transform infrared spectrometer (FTIR), thermo gravimetric analyzer (TGA), and scanning electron microscopy (SEM). The removal properties of Sr and Cs ions from aqueous solution were investigated in batch experiment. The removal efficiencies of Sr and Cs ions by the PVC-Zeolite beads were dependent on the initial pH of solution. The removal efficiencies sharply increased at below pH 4 and was kept constant at pH 4 or more. The adsorption kinetics of Sr and Cs ions by the PVC-Zeolite beads were fitted well by the pseudo-second-order model ($r^2$>0.99) more than pseudo-first-order model. The maximum adsorption capacities of Sr and Cs ions calculated from Langmuir isotherm model were 39.37 mg/g and 55.87 mg/g, respectively.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.360.1-360.1
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• 2016

Hydroxyapatite (Ca10(PO4)6(OH)2, HAP) particles have attracted a great deal of attention in biomedical fields due to their good biocompatibility, bioactivity and fairly broad applications as drug delivery, dental implant, bone cement, and etc. Thus, many researchers have made an effort to add new functionalities such as luminescence, drug delivery, and bone regeneration properties up to HAP powders by controlling their nanostructure as well as composition. In this research, the mesoporous strontium substituted HAP (Sr-HAP) microspheres were synthesized using a hydrothermal method. In this synthesis, aspartic acid monomers were utilized to form microsphere by controlling surface energy of HAP particles and Sr ions were substituted into Ca ion sites, which induced luminescence property in HAP powders. Moreover, the change in the amount of Sr substitution was found to influence the particle size, morphology, and concurrently surface area, which led to changing drug loading as well as drug release property. The amount of Sr influences the morphology, luminescent properties, particle size, surface area cell viability and drug loading property, which are investigated by SEM, TEM, XRD, FTIR, BET, XPS and in vitro test such as MTT assay and drug release test. In particular, the multifunctional Sr-HAP with molar ratios of 0.25 (Sr/(Ca+Sr)) possessed the strongest luminescent property as well as the superior drug loading and sustained release properties that were correspondent with large surface area and pore size. Our study indicates that the fabricated multifunctional Sr-HAP microspheres are quite useful for bone regeneration and drug delivery.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2003.10a
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• pp.537-541
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• 2003

The a-Si:H TFTs using ferroelectric of SrTiO$_3$, as a gate insulator is fabricated on glass. Dielectric characteristics of ferroelectric is better than SiO$_2$, SiN. Ferroelectric increases ON-current, decreases threshold voltage of TFT and also breakdown characteristics. The a-Si:H deposited by PECVD shows absorption band peaks at wavenumber 2,000 $cm^{-1}$ /, 635 $cm^{-1}$ / and 876 $cm^{-1}$ / according to FTIR measurement. Wavenumber 2,000 $cm^{-1}$ /, 635 $cm^{-1}$ / are caused by stretching and rocking mode SiH1. The wavenumber of weaker band, 876 $cm^{-1}$ / is due to SiH$_2$ vibration mode. The a-SiN:H has optical bandgap of 2.61 eV, refractive index of 1.8 - 2.0 and resistivity of 10$^{11}$ - 10$^{15}$ aim respectively. Insulating characteristics of ferroelectric is excellent because dielectric constant of ferroelectric is about 60 - 100 and breakdown strength is over 1 MV/cm. TFT using ferroelectric has channel length of 8 - 20 $\mu$m and channel width of 80 - 200 $\mu$m. And it shows drain current of 3 $\mu$A at 20 gate voltages, Ion/Ioff ratio of 10$^{5}$ - 10$^{6}$ and Vth of 4 - 5 volts.

• Progress in Superconductivity
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• v.3 no.1
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• pp.13-16
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• 2001

We have measured the reflectivity of superconducting infinite-layer compounds $Sr_{0.9}$ $Ln_{0.1}$ Cu $O_2$ (Ln=La, Gd, Sm) with $T_{c}$ : 39 K using a Fourier-transform infrared spectrometer. We have identified the optical phonon modes from their infrared reflectivity and conductivity spectra and have proposed possible displacement patterns. The La- and the Gd-doped compounds exhibited only four ($2A_{2u}$ $+2E_{u}$) out of the five ($2A_{2u}$ $3E_{u}$) infrared-active phonons predicted by a group theoretical analysis whereas the Sm-doped compound exhibited all five modes. For the La-doped sample, we investigated the temperature dependence of the optical response functions in a wide temperature range of 7 - 300 K. In FIR region, the reflectivity is apparently enhanced below ~120 $cm^{-1}$ as temperature decreases across $T_{c}$. The value of $2$\Delta$/k_{B}$ $T_{c}$ is about 4.5, which is consistent with maximum gap value of d-wave $high- T_{c}$ cuprates.> c/ cuprates.uprates.s.

• 한국초전도학회:학술대회논문집
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• v.11
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• pp.8-8
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• 2001