• Korean Journal of Environmental Agriculture
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• v.3 no.1
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• pp.52-56
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• 1984

In order to evaluate the applicability of two kinds of antibiotic fermentation residues on rice and tomato growth, yield, yield components, and some indicators for plant growing status were checked including analysis of physico-chemical properties of these two antibiotic fermentation residues. The results obtained are as follows: 1) These two antibiotic fermentation residues contain high organic matter ($21.6{\sim}24.2%$), phosphorus ($2900{\sim}4600 ppm$) and exchangeable cations ($55.4{\sim}138.3 meq/100 g$,), showing their pH values of $7.0{\sim}8.0$ range. 2) Both have developed net positive charge rather high and stiffly that exhibits high negative ion adsorption capacities, accordingly showing higher zero point of charges($pH 7.0{\sim}8.0$) than those of common soils. 3) The effect of the two kinds of antibiotic fermentation residues on rice growth was more or less the same comparable to the effect of the other fertilizers applied, showing the maximum yield at the application rate of 40 ㎏/10a. 4) The effect of these antibiotic fermentation residues on tomato growth was also similar to effects on rice plant showing the yield increment upon fertilizer application including two antibiotic fermentation residues but no significant differences among fertilizers. 5) According to the plant growing status, plant height, dry matter, number of effective tillers and grain number per panicle of rice and plant height and fresh weight of plant of tomato showed similar trend with yield of both plants.

• Applied Chemistry for Engineering
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• v.27 no.5
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• pp.516-520
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• 2016

Concentrated liquid detergents have 2~3 times higher surfactant contents [35~45% (w/w)] compared to those of normal type detergents. In general, a single surfactant forms a lyotropic liquid crystal (LC) phase when the concentration is in the region of 30~60% (w/w). Whereas the concentrated liquid detergent at about 40% (w/w) concentration in a mixed surfactant system shows an opaque appearance of gel or LC. In order to meet consumer needs and preference for product appearance, we applied hydrotropes and various surfactants systems in concentrated liquid detergents to obtain an opaque gel-phase and also a clear transparent phase at even below zero $^{\circ}C$ temperature. The more effective hydrotropes for making concentrated liquid detergents are 1,6-hexanediol, adipic acid and dipropylene glycol (DPG) which have two hydrophilic groups in both terminated positions. In order to prepare an excellent concentrated liquid detergent, good hydrotropes alongside secondary type surfactants like LAS and SAS were used. The formation of LC phase of concentrated liquid detergents at about 40% (w/w) concentration could be prevented by the use of both hydrotropes and secondary type surfactants. The result indicate that concentrated detergents having excellent low temperature stability and controlled viscosity can be prepared.

• Korean Journal of Food Science and Technology
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• v.20 no.4
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• pp.493-497
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• 1988

Peroxide value (POV), acid value (AV), color and flavor of soybean oil packaged with polyethylene (PE) bottle and Tetra-pack were periodically checked at $60^{\circ}C,\;40^{\circ}C$ for 33 days. POV more quickly increased when the storage temperature became higher. Kinetics of POV was followed the zero-order reaction rate. $Q_{10}$ values of those were in 1.8 in PE bottle and 2.1 in Tetra-pack at $20-40^{\circ}C$. Sensory scores were stable in PE bottle and Tetra-pack $20-40^{\circ}C$ and in Tetra-pack at $60^{\circ}C$, but those reached to the critical sensory point of 5 in PE bottle at $60^{\circ}C\;after\;30^{\circ}C$ days storage. Therefore, shelf-life of soybean oil could be predicted as 14.1 months and 7.8 months in PE bottle and 32.6 months and 22.5 months in Tetra-pack at $15^{\circ}C\;and\;25^{\circ}C$ by reaction rates of POV, $Q_{10}$ values and sensory scores.

• Journal of the Korean GEO-environmental Society
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• v.14 no.7
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• pp.19-29
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• 2013

Analysis via classical soil mechanics theory is either ineffective or inappropriate for fully describing stress distribution or failure conditions in cold regions, since mechanical properties of soils in cold regions are different from those reported in the classical soil mechanics theory. Therefore, collecting and analyzing technical data, and systematic and specialized research for cold regions are required for design and construction of the structure in cold regions. Freezing and thawing repeat in active layer of permafrost region, and a loading condition affecting the structure changes. Therefore, the reliable analysis of mechanical properties of frozen soils according to various conditions is prerequisite for design and construction of the structure in cold regions, since mechanical properties of frozen soils are sensitive to temperature condition, water content, grain size, relative density, and loading rate. In this research, the direct shear apparatus which operates at 30 degrees below zero and large-scaled low temperature chamber are used for evaluating shear strength characteristics of frozen soils. Weathered granite soil is used to analyzed the shear strength characteristics with varying freezing temperature condition, vertical confining pressure, relative density, and water content. This research shows that the shear strength of weathered granite soil is sensitively affected by various conditions such as freezing temperature conditions, normal stresses, relative densities, and water contents.

• Journal of Dental Rehabilitation and Applied Science
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• v.25 no.1
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• pp.61-71
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• 2009

Anchorage control is important in orthodontic treatment. Recently miniscrew is widly used as maximum anchorage in orthodontic treatment, and then it is important to install miniscrew safely without damaging adjacent anatomic structure. In a view of Miniscrew's stability, maxilla is unfavorable than mandible, and moreover maxillary soft buccal bone has disadvantage on stability. so palatal area comes into notice for installation area. We measured distance between palatal roots and bone thickness at midpalatal area using 3D computed tomography, and have found following results. 1. On the comparison of distance between palatal roots, the distance between 2nd premolar and 1st molar was significantly longest and the distance between premolars was significantly shortest. 2. Going toward lateral area from midpalatal suture and posterior area from zero point, bone thickness significantly became shorter and shorter. And 5.0mm palatal sagittal plane has more significance decrease of bone thickness than 2.5mm palatal sagittal plane. According to these results, we can conclude that the palatal installation of miniscrew between 2nd premolar and 1st molar is safest. And it is more safe that comes closer to midpalatal suture and to anterior area in regard to incisive canal.

• Journal of the Korean Chemical Society
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• v.61 no.6
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• pp.328-338
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• 2017

The density functional theory(DFT) and ab initio calculations have been applied to investigate hydrogen interaction of $H_2O_3(H_2O)_n$ clusters(n=1-5). The structures, IR spectra, and H-bonding energies are calculated at various levels of theory. The $trans-H_2O_3$ monomer is predicted to be thermodynamically more stable than cis form at the CCSD(T)/cc-pVTZ level of theory. For clusters, the geometries are optimized at the MP2/cc-pVTZ level of theory. The binding energy of $H_2O_3-H_2O$ cluster is predicted to be -6.39 kcal/mol at the CCSD(T)//MP2/cc-pVTZ level of theory after zero-point vibrational energy (ZPVE) and basis set superposition error (BSSE) correction. This result implies that $H_2O_3$ is a stronger proton donor(acid) than either $H_2O$ or $H_2O_2$. The average binding energies per $H_2O$ are predicted to be 8.25 kcal/mol for n=2, 7.22 kcal/mol for n=3, 8.50 kcal/mol for n=4, and 8.16 kcal/mol for n=5.

• The Journal of Korean Academy of Prosthodontics
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• v.31 no.3
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• pp.423-446
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• 1993

Titanium and its alloys are finding increasing use in medical devices and dental implants. The strong selling point of titanium is its resistance to the highly corrosive body fluids in which an implant must survive. This corrosion resistance is due to a tenacious passive oxide or film which exists on the metal's surface and renders it passive. Potentiodynamic polarization measurement is one of the most commonly used electro-chemical methods that have been applied to measure corrosion rates. And the potentiodynamic polarization test supplies detailed information such as open circuit, rupture, and passivation potential. Furthermore, it indicates the passive range and sensitivity to pitting corrosion. This study was designed to compare the corrosion resistance of the commonly used dental implant materials such as CP Ti, Ti-6A1-4V, Co-Cr-Mo alloy, and 316L stainless steel. And the effects of galvanic couples between titanium and the dental alloys were assessed for their useful-ness-as. materials for superstructure. The working electrode is the specimen , the reference electrode is a saturated calomel electrode (SCE), and the counter electrode is made of carbon. In $N_2-saturated$ 0.9% NaCl solutions, the potential scanning was performed starting from -800mV (SCE) and the scan rate was 1 mV/sec. At least three different polarization measurements were carried out for each material on separate specimen. The galvanic corrosion measurements were conducted in the zero-shunt ammeter with an implant supraconstruction surface ratio of 1:1. The contact current density was recorded over a 24-hour period. The results were as follows : 1. In potential-time curve, all specimens became increasingly more noble after immersion in the test solution and reached between -70mV and 50mV (SCE) respectively after 12 hours. 2. The Ti and Ti alloy in the saline solution were most resistant to corrosion. They showed the typical passive behavior which was exhibited over the entire experimental range. Therefore no breakdown potentials were observed. 3. Comparing the rupture potentials, Ti and Ti alloy had the high(:st value (because their break-down potentials were not observed in this study potential range ) followed by Co-Cr-Mo alloy and stainless steel (316L). So , the corrosion resistance of titanium was cecellent, Co-Cr-Mo alloy slightly inferior and stainless steel (316L) much less. 4. The contact current density sinks faster than any other galvanic couple in the case of Ti/gold alloy. 5. Ag-Pd alloy coupled with Ti yielded high current density in the early stage. Furthermore, Ti became anodic. 6. Ti/Ni-Cr alloy showed a relatively high galvanic current and a tendency to increase.

• Journal of Sensor Science and Technology
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• v.8 no.3
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• pp.239-246
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• 1999

A highly sensitive photovoltaic infrared photodiode was fabricated for detecting infrared light in $3{\sim}5\;{\mu}m$ wavelength range on InSb wafer with p-i-n structure grown by MOCVD. Silicon dioxide($SiO_2$) insulating films for the junction interface and surface of photodiode were prepared using RPCVD because InSb has low melting point and evaporation temperature. After formation of In ohmic contacts by thermal evaporation, the electrical properties of the photodiode were characterized in dark state at 77K. A product of zero-bias resistance and area($R_0A$) showed $1.56{\times}10^6\;{\Omega}{\cdot}cm^2$ that satisfied BLIP(background limited infrared photodetector) condition. When the photodiode was tested under infrared light, the normalized detectivity of about $10^{11}\;cm{\cdot}Hz^{1/2}{\cdot}W^{-1}$ was obtained. we successfully fabricated a unit cell with InSb IR array with good quantum efficiency and high detectivity.

• Korean Journal of Soil Science and Fertilizer
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• v.31 no.4
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• pp.407-413
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• 1998

The influence of the anion composition of simulated acid rain on cation leaching of two soils with different surface charge properties was examined. Four mixtures of mole ratio of $SO_4:NO_3$(1:0, 2:1, 1:1, 0:1) with pH 2.0 simulated acid rain were applied to an Inceptisols(Gyuam series) and Andisols(Pyeongdae series). The Andisols had higher $SO_4{^{2-}}$ adsorption capacity than the Inceptisols because of its higher point of zero charge(PZC, pH 6.5) than Inceptisols(PZC pH 3.1). Cation leaching in Andisols varied directly with the $NO_3$ content of the leaching input due to higher mobility of $NO_3$ compared with $SO_4$ that was absorbed. The pH of the Andisols was higher with the addition of $Na_2SO_4$ than the addition of $NaNO_3$ indicating that this soil behaves as a base and has a high $SO_4$ adsorption capacity. The relative $NO_3{^-}/SO_4{^{2-}}$ content input had no effect on cation leaching of the Inceptisols. Amounts of leaching on the Andisols by simulated acid rain were higher than Inceptisols. This experiment explained that anion composition of acid rain plays a significant role in the cation leaching of soils which are able to adsorb $SO_4$.

• Journal of IKEEE
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• v.23 no.1
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• pp.14-21
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• 2019

In this paper, we implemented an on-board miniaturization antenna operating 2.4 GHz using MZR(Mu Zero Resonator). It is must be operating under the constraint that the size of the small terminal PCB should be $78{\times}38{\times}0.8mm^3$ and the size of the system should be $63{\times}38{\times}0.8mm^3$ and the size of the radiating part should be $15{\times}38{\times}0.8mm^3$. The feeding structure uses a CPW structure for stable feeding and a feeding point at the upper left of the system board. A magnetic field coupling structure is used for coupling the feeding part and the antenna. The resonance frequency of the MZR is determined by the series inductance and capacitance of the cell, so the gap between the cells, the length of the cell, the length of the interdigital capacitor, and the spacing between the radiation part and the ground plane are analyzed. The antenna was designed and fabricated using the results. The total size of the antenna including the feed structure is $20.8{\times}9.0{\times}0.8mm^3$, and the electrical length is $0.1664{\lambda}_0{\times}0.072{\lambda}_0{\times}0.0064{\lambda}_0$. The measurement result for 10 dB bandwidth, gain and directivity are 440 MHz(18.3%), 0.4405 dB, and 2.722 dB respectively. It is confirmed that the radiation pattern has omnidirectional characteristics and it can be applied to ultra small terminal antenna.