• Journal of Power System Engineering
• /
• v.17 no.6
• /
• pp.149-155
• /
• 2013

Since bio-diesel oil has a merit that it satisfies both demand of substitution for fossil fuel and reduction in carbon dioxide emission, it is widely used in diesel engines by blending in gas oil in small quantity. It is needed to reduce in NOx emission in some way or others if blending ratio of bio-diesel oil is going to increase, because it is demerit that bio-diesel oil emits more NOx emission than gas oil. In this study, it was accomplished to optimize 3 factors what effect on NOx emission as blending ratio of bio-diesel oil, injection timing and common rail pressure with an introduction of a design of experiments, in order to minimize a number of tests. It was cleared that to introduce the design of experiments was very available in NOx optimization.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.17 no.1
• /
• pp.52-58
• /
• 2004

Magneto-Impedance(MI) sensor is a highly sensitive sensor, which was able to detect a weak geomagnetic field. It also has a merit to be able to build in the low power system. In this study, their magnetic permeability and anisotropy field(H$\sub$k/) as a function of some different thickness of sputtered amorphous CoZrNb films with zero-magnetostriction and soft magnetic property are investigated. In order to make a uniaxial anisotropy, film was subjected to the post annealing in a static magnetic field with 1KOe intensity at 250, 300, and 320$^{\circ}C$ respectively for 2 hours. Magnetic properties of films are measured by using a M-H loop tracer. Magnetic permeability of a film is measured over the frequency range from 1 ㎒ to 750㎒. By thickening a CoZrNb film relatively, magnetic permeability and impedance are examine to design the. MI sensor which drives at 50㎒, and thereof fabricated the MI sensor which drives at the 50㎒.

• Journal of the Microelectronics and Packaging Society
• /
• v.21 no.2
• /
• pp.31-35
• /
• 2014

The thickness dependent electrical, structural, and optical properties of ZnO films grown by atomic layer deposition (ALD) at various growth temperatures were investigated. In order to deposit ZnO films, diethylzinc and deionized water were used as metal precursor and reactant, respectively. ALD process window was found at the growth temperature range from $150^{\circ}C$ to $250^{\circ}C$ with a growth rate of about $1.7{\AA}/cycle$. The electrical properties were studied by using van der Pauw method with Hall effect measurement. The structural and optical properties of ZnO films were analyzed by using X-ray diffraction, field emission scanning electron microscopy, and UV-visible spectrometry as a function of thickness values of ZnO films, which were selected by the lowest electrical resistivity. Finally, the figure of merit of ZnO films could be estimated as a function of the film thickness. As a result, this investigation of thickness dependent electrical, structural, and optical properties of ZnO films can provide proper information when applying to optoelectronic devices, such as organic light-emitting diodes and solar cells.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2002.11a
• /
• pp.132-135
• /
• 2002

MI(Magneto-Impedance) sensor which is made by thin films has significantly high detecting sensitivity in weak magnetic field. It also has a merit to be able to build in the low power system. Its structure is simple, which makes it easier to prepare a miniature. In this study, its magnetic permeability and anisotropy field($H_{k}$) as a function of a thickness of sputtered amorphous CoZrNb films with zero-magnetostriction and soft magnetic property are investigated. In order to make a uniaxial anisotropy, film was subjected to the post annealing in a static magnetic field with 1KOe intensity at 250, 300, and $320^{\circ}C$ respectively for 2 hours. Magnetic properties of film are measured by using a MH loop tracer. Its magnetic permeability of a film is measured over the frequency range 1 MHz to 750MHz. And, it was examined on the permeability and impedance to design the MI sensor which acts at 50MHz by thickening a CoZrNb film relatively, and fabricated the MI sensor which acts at the 50MHz.

• Journal of Ginseng Research
• /
• v.22 no.2
• /
• pp.82-90
• /
• 1998

In order to stabilize the price of fresh ginseng by extension of seasonal variation and marketing structure, and to reduce the cost of production by works of intensive and short term, studies were carried out. As fresh ginseng of 4 years old by the MA and CA was stored for 12 week at 4$^{\circ}C$, samples were collected after every 1, 2, 3, 4, 6, 8, 12 weeks for processing red ginseng. Color and Sensual characteristics on ginseng steamed red for the quality evaluation are summarized as follows. For the time course of storage with red ginseng, which was processed from fresh one after various treatments, L and b values were decreased, however a value was increased. In particular, absorbance was step-wisely increased. Turbidity was somewhat increased, and non-treatment of preservative were shown 2 times higher of absorbance. Extraction ratio of ethanol-soluble extractives slightly increased by the preservation methods, and as storage period was passed. CA storage and preservative treat merit versus MA and non-preservative treatment gave much stability in ginseng quality. In the sensual characters, sour taste and sweet taste were increased, but fresh taste and rice scorched taste were decreased. Bitter taste was not much changed until end of storage. CA was shown smaller differences than MA in the pH change. Addition of preservative extended the storage time.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• v.2
• /
• pp.598-601
• /
• 2006

The radio signal in GNSS was intentionally designed with two frequencies in order to combat the dispersion error caused by trans-ionospheric propagation. By measuring the path delay independently at the two, widely spaced GPS frequencies, L1 & L2, the TEC along the path from satellite to receiver can be measured directly. The issue with dual frequency measurement of the ionosphere is the calibration of L1/L2 interfrequency biases. L1/L2 interfrequency biases are generated because physical electric signal paths of L1 and L2 circuits are different from each other for both satellites and receiver. Conventionally L1/L2 interfrequency bias is estimated and broadcasted by 2D ionospheric model. In this paper, we estimated IFB (interfrequency bias) by 2D & 3D ionospheric models including real time filter methods and compared the result of those and concluded the merit of 3D tomography model to recover the problem of 2D thin shell model. We confirmed our conclusion by experimental data.

• Journal of the Korean Ceramic Society
• /
• v.41 no.10 s.269
• /
• pp.771-776
• /
• 2004

[ $Ba(Zr_{0.08}Ti_{0.92})O_3$ ] polycrystal was grown by floating zone technique with two ellipsoidal mirrors using the $8\%$of Zr-modified BZT ceramics as both a feed rod and a seed crystal. In order to study the annealing effect, a part of the grown crystal was sliced and annealed in the oxygen atmosphere at $1,200^{\circ}C$ for 10 h. The dielectric constant and loss at 10 kHz, 100 kHz, and 1 MHz were measured in the temperature range between $-100^{\circ}C$ and $150^{\circ}C$ to investigate the dielectric properties of the grown polycrystal. The electric-field dependence of the dielectric constant at 10 kHz and 100 kHz was studied by measuring the dielectric constants as a function of the biased-electric fields which ran from -15 kV/cm to 15 kV/cm. Due to the effect of annealing in the oxygen atmosphere, the electric-field tunability of dielectric constants increased from $47.5\%$ to 5 to and the figure of merit for this material from 39.6 to 46.4. Since the figure of merit can be increased to more than 46.4 by increasing the maximum value of the biased-electric fields to more than 15 V/cm, this material nay have a possibility for applications in microwave tuning devices at room temperature.

• Journal of the Korean Vacuum Society
• /
• v.20 no.5
• /
• pp.356-360
• /
• 2011

Indium oxide ($In_2O_3$) single layer and $In_2O_3$/copper (Cu) bi-layer films were prepared on glass substrates by RF and DC magnetron sputtering without intentional substrate heating. In order to determine the effect of the Cu bottom layer on the optical, electrical and structural properties of $In_2O_3$ films, 3-nm-thick Cu film was deposited on the glass substrate prior to deposition of the $In_2O_3$ films. As-deposited $In_2O_3$ films had an optical transmittance of 79% in the visible wavelength region and a sheet resistance of 2,300 ${\Omega}/{\square}$, while the $In_2O_3$/Cu film had optical and electrical properties that were influenced by the Cu bottom layer. $In_2O_3$/Cu films had a lower sheet resistance of 110 ${\Omega}/{\square}$ and an optical transmittance of 71%. Based on the figure of merit, it can be concluded that the Cu bottom layer effectively increases the performance of $In_2O_3$ films for use as transparent conducting oxides in flexible display applications.

• Korean Journal of Materials Research
• /
• v.24 no.3
• /
• pp.145-151
• /
• 2014

Solution-based Sb-doped $SnO_2$ (ATO) transparent conductive oxides using a low-temperature process were fabricated by an electrospray technique followed by spin coating. We demonstrated their structural, chemical, morphological, electrical, and optical properties by means of X-ray diffraction, X-ray photoelectron spectroscopy, field-emission scanning electron microscopy, atomic force microscopy, Hall effect measurement system, and UV-Vis spectrophotometry. In order to investigate optimum electrical and optical properties at low-temperature annealing, we systemically coated two layer, four layer, and six layers of ATO sol-solution using spin-coating on the electrosprayed ATO thin films. The resistivity and optical transmittance of the ATO thin films decreased as the thickness of ATO sol-layer increased. Then, the ATO thin films with two sol-layers exhibited superb figure of merit compared to the other samples. The performance improvement in a low temperature process ($300^{\circ}C$) can be explained by the effect of enhanced carrier concentration due to the improved densification of the ATO thin films causing the optimum sol-layer coating. Therefore, the solution-based ATO thin films prepared at $300^{\circ}C$C exhibited the superb electrical (${\sim}7.25{\times}10^{-3}{\Omega}{\cdot}cm$) and optical transmittance (~83.1 %) performances.

• Journal of Korean Physical Therapy Science
• /
• v.4 no.1
• /
• pp.315-327
• /
• 1997

The purpose of this thesis is to investigate the application of a medical cure with a mixture of the merit of a hydrotherapy, as a kind of a physical therapy, and the remedy efficacy of mugwort, which uses in a chinese medical treatment in order to remove an unpleasant smell of HOT Pack and its tube to use in hospital. The usability of mugwort and the degree of its preference was obtained through question naires sent to 120 students including 50 students of the department of physical therapy. And the feeling, at the moment a HOT Pack Tube was opened, was investigated through 74-physical therapists. This research is to investigate the effect of the remedy to add a mugwort-pack in a HOT Pack tube using already in hospital. The results of this study are as following : The efficacy of a mugwort-pack to get rid of an unpleasant smell got better than that of a HOT Pack and its tube. As most of physical therapy laboratory lies to a basement of a hospital, the efficacy to remove a particular offensive smell of a basement got better than that of a HOT Pack using in a common hospital. Also, the degree of patients' preference on a HOT Pack to add with mugwort got to be higher and increased gradually. I can't see the definite difference of a medical remedy, but, I suppose that the visible feeling was of much help for the effect of patients's remedy.