• Journal of the Korea Society of Computer and Information
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• v.25 no.10
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• pp.231-240
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• 2020

Countries around the world have already taken direct and indirect measures to warn of the harmful effects of mobile phone electromagnetic waves. On the other hand, in the Republic of Korea the installation of Wi-Fi has been expandedwithout restrictions by location, and there is a widespread atmosphere of protesting human rights violations even if young students cannot use mobile phones, ignoring problems caused by the use of mobile phones. Human brain cells are increasingly exposed to electromagnetic waves of mobile phones as the penetration rate of smartphones grows.In order to solve the long-lasting question of whether electromagnetic waves from mobile phones will harm the human body, many studies are being conducted in various countries around the world, andthe recently published findingshave warned of the potential for harm. The labeling of electromagnetic waves alone is not sufficient to raise awareness about the dangers of electromagnetic waves. It is necessary that the Republic of Korea organize and operate a national electromagnetic wave research center in line with its status as an IT powerhouse, along with the revision of the Radio Wave Act, which directly warns the public about the hazards of mobile phone electromagnetic waves and can directly impose obligations on the mobile phone industry.

• Journal of Magnetics
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• v.19 no.1
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• pp.59-63
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• 2014

Nano-sized nickel substituted cobalt ferrite powders, $Ni_xCo_{1-x}Fe_2O_4$ ($0.0{\leq}x{\leq}1.0$), were fabricated by the sol-gel method, and their crystallographic and magnetic properties were studied. All the ferrite powders showed a single spinel structure, and behaved ferrimagnetically. When the nickel substitution was increased, the lattice constants and the sizes of particles of the ferrite powders decreased. The M$\ddot{o}$ssbauer absorption spectra of $Ni_xCo_{1-x}Fe_2O_4$ ferrite powders could be fitted with two six-line subspectra, which were assigned to a tetrahedral A-site and octahedral B-sites of a typical spinel crystal structure. The increase in values of the magnetic hyperfine fields indicated that the superexchange interaction was stronger, with the increased nickel concentration in $Ni_xCo_{1-x}Fe_2O_4$. This could be explained using the cation distribution, which can be written as, $(Co_{0.28-0.28x}Fe_{0.72+0.28x})[Ni_xCo_{0.72-0.72x}Fe_{1.28-0.28x}]O_4$. The two values of the saturation magnetization and the coercivity decreased, as the rate of nickel substitution was increased. These decreases could be explained using the cation distribution, the magnetic moment, and the magneto crystalline anisotropy constant of the substituted ions.

• The Journal of Korean Academy of Prosthodontics
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• v.33 no.2
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• pp.317-334
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• 1995

The purpose of this study was to compare the bone formation, maturation around HA-and titaniumcoated dental implants in dog. 5 hydroxyapatite coated IMZ implants and 5 titanium coated IMZ implants were placed into the previously extracted site in the mandible of 5 adults dogs. All dogs were injected intravenously Tetracycline, Alizalin red S, and Calcein for bone fluorescent labelling, After the experimental period of 16weeks, the dogs were sacrificed and tissue samples around the implants were obtained. Microscopic observations(ligth, polariged and fluorescence microscope), morphometric analysis, line profile with EPMA, and quantitative analysis for Ca,P, and Ti were performed. The results were as follows ; 1. Bone maturations around the implants were relatively lower than those of natural teeth. No significant differences in bone maturation and remodeling patterns were observed between the two implants groups. 2. Calcification of bone surrounding the implants was initiated in 8-11 weeks for HA-coated implants, while it took 11 weeks or more for Ti-coated implants. 3. Bone-to-implants contact ratio of 82.63% was recorded for HA-coated group and 72.25% for titanium coated group, with no significant difference between the two groups. 4. Bone around the implants exhibited reduced quantity of Ca and P in the $100{\mu}m$ region relative to natural teeth, while the rest of the regions showed no statistical differences. No significant differences were found between the two implant groups. 5. There was a separation of HA layer from the implant core and subsequent infiltration of inflammatory cells into the resulting space in the HA-coated implants, and evidences of phagocytosis of HA particles by macrophages. Bone calcification was more rapid around HA-coated implants compared to titanium-coated implants, but HA coated implants did not show any significant differences either in the degree of calcification or the bone-to-implant contact ratio over Ti coated implants. HA coated implants may have complications associated with HA absorption and separation of HA layer from the implant core.

• Particle and aerosol research
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• v.6 no.2
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• pp.51-59
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• 2010

ZnO quantum dots embedded in a silica matrix without agglomeration were synthesized from $TEOS:Zn(NO_3)_2$ solutions in one-step process by aerosol-gel method. It was successfully demonstrated that the size of ZnO Q-dots could be controlled from 2 to 7 mm verified by a high resolution transmission electron microscope observation. The line scanning energy dispersive X-ray spectroscopy(EDS) revealed that the Q-dots existed preferentially inside SiO2 sphere when Zn/Si < 0.5. However, the Q-dots distributed homogeneously all over the sphere when Zn/Si > 1.0. Blue-shifted UV/Vis absorption peak observation confirmed the quantum size effect on the optical properties. The photoluminescence(PL) emission peaks of the powders at room temperature were consistent with previous reports in the following aspects: 1) PL characteristics are dominated by two peaks of deep-level defect-related emissions at 2.4 - 2.8 eV, 2) the first defect-related peak at 2.4 eV was blue shifted due to the quantum size effect with decreasing the concentration of $Zn(NO_3)_2$(decreasing the size of ZnO q dots). More interestingly, the existence of surface-exposed ZnO q dots affects greatly the second defect PL peak at 2.8 eV.

• The Bulletin of The Korean Astronomical Society
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• v.38 no.2
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• pp.36-36
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• 2013

Globular clusters (GCs) are among the oldest stellar objects in the universe and provide valuable constraints on many aspects of galaxy evolution. GC systems typically exhibit bimodal color distributions the phenomenon of which has been a major topic in the area of GC research. GC color bimodality established a paradigm where scenarios to explain its origin require two GC groups with different formation origins. The GC division, asserted mainly by photometric color bimodality so far, has been viewed as the presence of two distinct metallicity subgroups within individual galaxies. In this study, we make use of spectroscopy of GC systems associated with two giant galaxies, M31 (the Andromeda) and M87 (NGC 4486), to investigate the GC bimodality and the underlying metallicity distributions. Recent spectroscopy on the globular cluster (GC) system of M31 with unprecedented precision witnessed a clear bimodality in absorption-line index distributions of old GCs. Given that spectroscopy is a more detailed probe into stellar population than photometry; the discovery of index bimodality may point to the very existence of dual GC populations. However, here we show that the observed spectroscopic dichotomy of M31 GCs emerges due to the nonlinear nature of metallicity-to-index conversion and thus one does not necessarily have to invoke two separate GC subsystems. We present spectra of 130 old globular clusters (GCs) associated with the Virgo giant elliptical galaxy M87, obtained using the Multi-Object Spectrography (MOS) mode of Faint Object Camera and Spectrograph (FOCAS) on the Subaru telescope. M87 GCs with reliable metallicity measurements exhibit significant inflection along the color-metallicity relations, through which observed color bimodality is reproduced from a broad, unimodal metallicity distribution. Our findings lend further support to this new interpretation of the GC color bimodality, which could change much of the current thought on the formation of GC systems and their host galaxies.

• 한국생물공학회:학술대회논문집
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• 2003.04a
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• pp.74-78
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• 2003

Multi-channel images of 11-MUA and 11-MUOH self-assembled monolayers were obtained by using two-dimensional surface plasmon resonance (SPR) absorption. Patterning process was simplified by exploiting direct photo-oxidation of thiol bonding (photolysis) instead of conventional photolithography. Sharper images were resolved by using a white light source in combination with a narrow bandpass filter in the visible region, minimizing the diffraction patterns on the images. The line profile calibration of the image contrast caused by different resonance conditions at each points on the sensor surface (at a fixed incident angle) enables us to discriminate the monolayer thickness in sub-nanometer scale. Furthermore, there is no signal degradation such as photo bleaching or quenching which are common in the detection methods based on the fluorescence.

• Proceedings of the Korean Society of Near Infrared Spectroscopy Conference
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• 2001.06a
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• pp.1192-1192
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• 2001

Usually there are many furnaces in a ethylene plant and the performance of total furnaces can be improved if that of each furnace is monitored and controlled. For this purpose real-time data for the effluent of each furnace is necessary. However, it is very difficult to analyze the total effluent stream of a ethylene furnace by real-time because it is composed of so many components including heavy hydrocarbons. Fortunately, component data for lighter hydrocarbons is much more important than that of heavier ones for ethylene furnace. In ordinary case, the on-line measurement of light hydrocarbons is performed by on-stream gas chromatography, after separating gas-phase part from effluent. The main and important components of gas-phase are Methane, Ethane, Ethylene, and Propylene. If we can use Near-infrared spectroscopy for measuring those components within good reproducibility, shorter analysis time, better repeatability, easier maintenance and lower cost will make Near-infrared (NIR) analyzer replace on-stream gas chromatography in this process. Although it is known to be very difficult to measure gas components because of very weak absorption in Near-infrared region, we have studied the feasibility of the application of NIR for the measurement of gas-phase hydrocarbon in the effluent of ethylene furnace. The samples were obtained from actual process and NIR spectra were collected over 1100 to 2500nm range. NIR spectra and calibrations showed and demonstrated the possibility of extending NIR spectroscopy to the measurement of gas-phase hydrocarbon in the effluent of ethylene furnace.

• Journal of the Korean Graphic Arts Communication Society
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• v.28 no.1
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• pp.15-24
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• 2010

Photovoltaic solar cells are all in the incident because they are not converted into electrical energy, high-efficiency solar cells in order to reduce the loss of elements must be. Significant factor in the loss of solar cells, optical loss and electrical loss can be divided into. Optical losses occur when the sun will be joined on the surface of the reflection, the shadow loss due to electrodes, and the losses are in the solar wavelengths. Commercialization is currently the most common solar cells on the front of the light incident on the electrode is formed. Therefore, the shadow caused by the electrode to cover the dead area of the sun, due to factors that hinder the absorption of sunlight which is shadowing them and conversion efficiency of solar cells is the inhibition factor. These barriers to eliminate the electrode linewidth reduces the shadowing to reduce, but simply of the electrode line width is reduced electrode area by reducing the series resistance elevates this because to improve the electrode Aspect ratio(height/width) to increase Ag development of paste is required. In this study, aspect ratio of screen-printing method to increase the electrode Ag paste composition of the binder for the characterization of rheology in the shadow of the electrode by reducing the optical loss of the photoelectric conversion efficiency of solar cells to boost the performance measures was. Properties and printability of the paste, the binder resin sintered characteristics that affect the thermal properties are excellent with a good screen printability acrylic resin, ethyl cellulose, using a resin were evaluated. Prepared paste rheology properties, was formed to evaluate the electrode conductivity and aspect ratio.

• BMB Reports
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• v.30 no.6
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• pp.397-402
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• 1997

A thiol-specific spin label was attached to cysteine-102 of yeast cytochrome c and electron paramagnetic resonance (EPR) spectra were measured as a function of added cytochrome c oxidase concentration. The intensity decreased due to line broadening as cytochrome c formed a complex with cytochrome c oxidase and reached a minimum when the ratio of cytochrome c to cytochrome c oxidase became one. Replacement of either Lys-72 or Lys-87 of cytochrome c by Glu did not result in a significant change in binding affinity. Interestingly the K72E mutant, unlike K87E, had a much lower rate of electron transfer than the wild type. These results indicate that many positively charged residues as a group participate in complex formation but Lys-72 might be important for cytochrome c to be locked in an orientation for an efficient electron transfer. A stoichiometry of 1 was also confirmed by optical absorption of the cytochrome c-cytochrome c oxidase complex which had been run through a gel chromatography cloumn to remove unbound cytochrome c. The EPR spectrum of this 1:1 complex, however, was a mixture of two components. This explains a biphasic kinetics for a single binding site on cytochrome c oxidase without invoking conformational transition.

• Biomolecules & Therapeutics
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• v.25 no.5
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• pp.553-558
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• 2017

Paclitaxel (PTX) is one of the most frequently used anticancer agent for treating refractory ovarian cancer, metastatic breast cancer and non-small cell lung cancer. However, its oral administration is impeded by very low bioavailability (<5%) due to the P-glycopprotein (P-gp) efflux pump effect. This study investigated in vitro and in vivo P-gp inhibitory effects of adamantyl derivatives AC-603 and AC-786 in rats. Two adamantyl derivatives tested in this study increased the cytotoxicity of daunomycin (DNM) in P-gp overexpressed cell line by inhibiting P-gp efflux function. Pharmacokinetics of PTX with orally co-administered P-gp inhibitors were assessed in rats to improve PTX absorption. The pharmacokinetic parameters of PTX were determined in rats after intravenous (2 mg/kg) or oral (25 mg/kg) administration in the presence or absence of verapamil (a positive control), AC-603 or AC-786 (0.5 mg/kg or 5 mg/kg). Compared to control group (PTX alone), experimental groups (PTX with AC-603 or AC-786) significantly increased the area under the plasma concentration-time curve of PTX following oral administration by 1.7-2.2 fold. The volume of distribution and total clearance of PTX were decreased, while other parameters were not significantly changed. In conclusion, co-administration of AC-603 or AC-786 enhanced the relative bioavailability of orally administered PTX as compared to control.