• Journal of the Korean Society of Clothing and Textiles
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• v.41 no.1
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• pp.131-140
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• 2017

Uniform nanofibers of polyurethane with different content of Juniperus Chinensis extracts (JCE) were successfully prepared by the electrospinning method. We investigated physiochemical properties of prepared compound nanoweb according to various concentrations of Juniperus Chinensis extracts using a Fourier transform infrared (FT-IR) spectrometer, X-ray diffractometer (XRD), thermogravimeter (TGA), and differential scanning calorimeter (DSC). The antibacterial activity of the JCE loaded PU nanofiber was conducted using the disk diffusion test against Gram-positive and Gram-negative bacteria. JCE was induced in the infrared spectra in the absorption band of PU/JCE nanowebs at $3,300cm^{-1}$, $2,960cm^{-1}$, $1,400-1,600cm^{-1}$, and $1,050cm^{-1}$. Thermal stability decreased with increasing JCE content in the PU/JCE nanowebs. The DSC curve of the PU nanoweb shows an endotherm peak at $420^{\circ}C$; in addition, the peak also became smaller and broader with increasing JCE content. The diffraction intensities of PU observed at 2 theta of $20^{\circ}$ decreased with the increasing amount of JCE in the compound nanoweb. In addition, the crystal intensities of the compound nanowebs also decreased along with the JCE content. Structural analysis indicates that JCE and PU are miscible. Juniperus Chinensis incorporated PU nanofibers demonstrated excellent antibacterial properties against both Gram-positive and Gram-negative bacteria.

• Journal of Astronomy and Space Sciences
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• v.2 no.1
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• pp.19-33
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• 1985

The singularities of differential Newtonian equation of motion in three body problem cause the loss of accuracy and the considerable increase of the computer time. These singularities could be eliminated during the process of regularization to transform the independent variables and the coordinate of Newtonian equations of motion. In this study, we calculated the positions and velocities of three body along the time scale to find out the unique solution of regularized Newtonian equations of motion with the $5^{th}$ order Runge-Kutta method by assuming the suitable initial velocities and positions. As the results of these calculations it is shown that the tripe stellar system eventually distintegrated, two of them formed a binary, and the last one escaped from this system with a hyperbolic orbit. This may suggest one possible explanation for the binary formation.

• Journal of Astronomy and Space Sciences
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• v.25 no.4
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• pp.395-404
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• 2008

We explore the linkage between the long term variability of the Sun and earth's climate change by analysing periodicities of time series of solar proxies and global temperature anomalies. We apply the power spectral estimation method named as the periodgram to solar proxies and global temperature anomalies. We also decompose global temperature anomalies and reconstructed total solar irradiance into each local variability components by applying the EMD (Empirical Mode Decomposition) and MODWT MRA (Maximal Overlap Discrete Wavelet Multi Resolution Analysis). Powers for solar proxies at low frequencies are lower than those of high frequencies. On the other hand, powers for temperature anomalies show the other way. We fail to decompose components which having lager than 40 year variabilities from EMD, but both residuals are well decomposed respectively. We determine solar induced components from the time series of temperature anomalies and obtain 39% solar contribution on the recent global warming. We discuss the climate system can be approximated with the second order differential equation since the climate sensitivity can only determine the output amplitude of the signal.

• Korean Journal of Materials Research
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• v.21 no.1
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• pp.67-71
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• 2011

La doped CuO-ZnO-$Al_2O_3$ powders are prepared by sol-gel method with aluminum isopropoxide and primary distilled water as precursor and solvent. In this synthesized process, the obtained metal oxides caused the precursor such as copper (II) nitrate hydrate and zinc (II) nitrate hexahydrate were added. To improve the surface areas of La doped CuO-ZnO-$Al_2O_3$ powder, sorbitan (z)-mono-9-octadecenoate (Span 80) was added. The synthesized powder was calcined at various temperatures. The dopant was found to affect the surface area and particle size of the mixed oxide, in conjunction with the calcined temperature. The structural analysis and textual properties of the synthesized powder were measured with an X-ray Diffractometer (XRD), a Field-Emission Scanning Electron Microscope (FE-SEM), Bruner-Emmett-Teller surface analysis (BET), Thermogravimetry-Differential Thermal analysis (TG/DTA), $^{27}Al$ solid state Nuclear Magnetic Resonance (NMR) and transform infrared microspectroscopy (FT-IR). An increase of surface area with Span 80 was observed on La doped CuO-ZnO-$Al_2O_3$ powders from $25m^2$/g to $41m^2$/g.

• Polymer(Korea)
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• v.28 no.2
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• pp.194-200
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• 2004

Porcine small intestine submucosa (SIS) has been widely used as a biomaterial without immunorejection responses. Crosslinked SIS sponges were characterized for the possibility of the bio-interactive wound dressings and tissue engineered scaffolds. SIS powders were dissolved in 3% acetic acid aqueous solution at 48hrs followed by pouring into mold and then fabricated by freeze-drying method. SIS sponge was prepared by crosslinked with 1-ethyl-(3-3-dimethyl aminopropyl) carbodiimide hydrochloride (EDC) solution (deionized water: ethanol=5:95) with 1-100mM concentration for 24 hrs and Iyophilized. SIS sponges were characterized by scanning electron microscopy, differential scanning calorimeter, and Fourier transform infrared spectrometer and were tested their porosity and water absorption ability. It was observed that the concentration of EDC might be exceeded 50 mM to get good physical characteristics. In conclusion, it seems that SIS sponge could be very useful for the applications of wound healing and tissue construction.

• Korean Journal of Medicinal Crop Science
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• v.26 no.5
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• pp.417-429
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• 2018

Background: The objective of this study was to make colloidal dispersions of the active compounds of radix of Angelica gigas Nakai that could be charaterized as nano-composites using hot melt extrusion (HME). Food grade hydrophilic polymer matrices were used to disperse these compound in aqueous media. Methods and Results: Extrudate solid formulations (ESFs) mediated by various HPMCs (hydroxypropyl methylcelluloses) and Na-Alg polymers made from ultrafine powder of the radix of Angelica gigas Nakai were developed through a physical crosslink method (HME) using an ionization agent (treatment with acetic acid) and different food grade polymers [HPMCs, such as HP55, CN40H, AN6 and sodium alignate (Na-Alg)]. X-ray powder diffraction (XRD) analysis confirmed the amorphization of crystal compounds in the HP55-mediated extrudate solid formulation (HP55-ESF). Differential scanning calorimetry (DSC) analysis indicated a lower enthalpy (${\Delta}H=10.62J/g$) of glass transition temperature (Tg) in the HP55-ESF than in the other formulations. Infrared fourier transform spectroscopy (FT-IR) revealed that new functional groups were produced in the HP55-ESF. The content of phenolic compounds, flavonoid (including decursin and decursinol angelate) content, and antioxidant activity increased by 5, 10, and 2 times in the HP55-ESF, respectively. The production of water soluble (61.5%) nano-sized (323 nm) particles was achieved in the HP55-ESF. Conclusions: Nano-composites were developed herein utilizing melt-extruded solid dispersion technology, including food grade polymer enhanced nano dispersion (< 500 nm) of active compounds from the radix of Angelica gigas Nakai with enhanced solubility and bioavailability. These nano-composites of the radix of Angelica gigas Nakai can be developed and marketed as products with high therapeutic performance.

• Korean Journal of Materials Research
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• v.18 no.5
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• pp.235-240
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• 2008

This paper presents results and observations obtained from a study of the optical and thermal properties of alkali tellurite depending on the composition. Fourier transform infrared (FT-IR) spectra showed evidence of chemical modification from $TeO_4$ trigonal bipyramids (tbp) to $TeO_3$ trigonal pyramids (tp) in tellurite glasses. The optical band gaps of the different glass samples calculated using Tauc's method were found to range from 3.5-3.8 eV. The glass transition temperature (Tg) and glass stability (${\Delta}T$) of alkali tellurite glasses were investigated, as $M_2O$ [M: Li, Na, K] amounted to 25 mol%, through the use of differential thermal analysis (DTA). The coefficient of thermal expansion (CTE) was measured in a thermo mechanical analysis (TMA) with a slow heating rate after the glass samples were annealed. The results confirm that the optical band gap of alkali tellurite glasses depends on the Te-O-Te structural relaxation related to the ratio of bridging/non bridging oxygen (BO/NBO). In contrast, the thermal properties are related to the ionic field strength of the Te-O-M and M-O-M bonds, and the Te-O-Te breakage depends on the ratio of BO/NBO.

• Journal of Pharmaceutical Investigation
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• v.41 no.3
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• pp.179-184
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• 2011

This study aimed to confirm the effect of molecular weight (MW) in solid dispersion of carvedilol with poly-vinylpyrrolidone (PVP) of various MW. Solid dispersion of carvedilol with PVP was prepared by spray-drying method. Scanning electron microscopy (SEM) was used to analyze the surface of solid dispersion samples. Differential scanning calorimetry (DSC) and X-ray diffraction (XRD) were used to analyze the crystalline of solid dispersion. Fourier transform infrared spectroscopy (FT-IR) was used to analyze the change of chemical structure characteristic of solid dispersion. DSC and XRD show that drug crystalline was changed. FT-IR revealed that chemical structure of solid dispersion comparing the chemical structure of drug was changed. The dissolution studies of solid dispersion presented at simulated gastric juice (pH 1.2). The dissolution rate of solid dispersion was dramatically enhanced than pure drug and the MW of PVP has an effect on the release property of carvedilol in solid dispersion. In conclusion, the present study has confirmed the effect of MW of PVP on release property of solid dispersion formulation of carvedilol with PVP.

• Journal of the Korean Vacuum Society
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• v.6 no.3
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• pp.213-219
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• 1997

The plasma polymerized styrene films were prepared by using an inter-electrode capacitively coupled gas-flow-type reactor, and the effects of plasma polymerization condition on the molecular weight distribution were investigated by Fourier Transform Infrared (FT-IR), Pyrolysis Gas Chromatography(PyGC), Differential Scanning Calorimetry(DSC) and Gel Permeation Chromatography(GPC). From the above results, the very cross-linked films different from chemical characteristics of the starting monomer were taken out, and it is realized that the molecular structure, cross linking density, and molecular weight distribution could be controlled by changing the parameters such as deposition pressure, deposition power and gas flow rate. Accordingly, it is suggested that plasma polymerization method performed by inter-electrode capacitively coupled gas-flow-type reactor has good characteristics for manufacturing the functional organic thin films which can be applied in sensors, opto-electric device, photo-resist by changing the polymerization parameters.

• Korean Journal of Medicinal Crop Science
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• v.26 no.4
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• pp.317-327
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• 2018

Background: The root of Angelica gigas Nakai is used as a traditional herbal medicine in Korea for the treatment of many diseases. However, the poor water solubility of the active components in A. gigas Nakai is a major obstacle to its bioavailability. Methods and Results: This work aimed at enhancing the solubility of the active compounds of A. gigas Nakai by a chemical (using a surfactant) and physical (hot melt extrusion, HME) crosslinking method. Fourier transform infrared spectroscopy revealed multiple peaks in the case of the extrudate solids, attributable to new functional groups including carboxylic acid, alkynes, and benzene derivatives. Differential scanning calorimetry analysis showed that the extrudate soilid had a lower glass transition temperature ($T_g$) and enthalpy (${\Delta}H$) ($T_g:43^{\circ}C$, ${\Delta}H$ : < 6 J/g) as compared to the non-extrudate ($T_g:68.5^{\circ}C$, ${\Delta}H:123.2$) formulations. X-ray powder diffraction analysis revealed the amorphization of crystalline materials in the extrudate solid. In addition, enhanced solubility (53%), nanonization (403 nm), and a higher amount of extracted phenolic compounds were achieved in the extrudate solid than in the non-extrudate (solubility : 36%, nanonization : 1,499 nm) formulation. Among the different extrudates, acetic acid and span 80 mediated formulations showed superior extractions efficiency. Conclusions: HME successfully enhanced the production of amorphous nano dispersions of phenolic compound including decursin from extrudate solid formulations.