• Journal of the Korean Vacuum Society
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• v.22 no.4
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• pp.181-187
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• 2013

$Dy^{3+}$-doped $BaMoO_4$ phosphor powders were synthesized by using the solid-state reaction method and their crystalline structure, morphology and size of particles, excitation and emission properties were investigated. The structure of all the phosphor powders, irrespective of the mol ratio of $Dy^{3+}$ ions, was found to be the tetragonal system with the main diffraction peak at (112) plane. The grain particles agglomerate together to form larger clusters with increasing the mol ratio of $Dy^{3+}$ ions. The excitation spectra were composed of a broad band centered at 293 nm and weak multiline peaked in the range of 230~320 nm, which were due to the transitions of $Dy^{3+}$ ions. The emission of the phosphors peaking at 666 and 754 nm, originating from the transitions of $^4F_{9/2}{\rightarrow}^6H_{11/2}$ and $^4F_{9/2}{\rightarrow}^6H_{9/2}$ of $Dy^{3+}$ ions, was rather weak, while the intensity of blue and yellow emission peaking at 486 nm and 577 nm due to the transitions of $^4F_{9/2}{\rightarrow}^6H_{15/2}$ and $^4F_{9/2}{\rightarrow}^6H_{13/2}$ of $Dy^{3+}$ ions was significantly stronger. The experimental results suggest that the white-light emission can be realized by controlling the yellow-to-blue intensity ratio of $Dy^{3+}$ emission.

• Journal of Wetlands Research
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• v.20 no.1
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• pp.80-93
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• 2018

Research trend about nonpoint pollution source(NPS) that have studied since 1980 was divided into 4 categories: 1) runoff characteristics of NPS, 2) treatment technique, 3) LID and green infrastructure(GI), 4) management practices and policy. This study reviews them and recommends the future research direction. The research on runoff characteristics of NPS until 2010 was mainly carried out. But recently, many researchers has been conducting studies on technology development, effect evaluation and field application. Providing best measures on NPS should be tried to conduct studies that many fields such as society, geography, meteorology and environment are fused. But it has not been enough yet. Because the cause material and optimum measures of NPS are different from each other regionally, it is considered that it needs studies to prepare measures and guidelines with regional characteristics rather than a uniform measures and guidelines by the central government. In addition, more comprehensive studies must be carried out to establish rules and regulations to manage NPS not only by government sector but also the private sector.

• Weed & Turfgrass Science
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• v.5 no.3
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• pp.111-125
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• 2016

Cordgrass (Spartina spp.) is recognized as a highly invasive plant in estuaries throughout the world because of remarkable versatility and resiliency, significant reproduction, strong adaptability, rapid spreading, and vigorous growth. In this review, therefore, to provide insights on the effective management practices, the previous research works were summarized and discussed. Spartina spp. is a perennial halophyte, warm-season (C4) grass that reproduces both sexually through seeds and asexually by rhizomes. Management strategies for cordgrass have included various physical, biological, and chemical controls. Herbicides are usually the most cost-effective means of control. Currently, glyphosate, imazapyr, fluazifop and haloxyfop have been practically used. To improve the control efficacy, a combination of two more than methods (example, mowing-spraying) is needed to be applied consistently every year for at least 3 to 4 years and to be sprayed with enough dry time (>4-6 hr) at an early growth stage (before flowering). Consistently repeated application of same herbicide have to be avoided to prevent an unexpected emergence of herbicide-resistant lines. On the other hand, Spartina spp. have many positive functions for agricultural and eco-engineering purposes. Thus, we have to give more intensive research for effectively managing advantages and disadvantages of Spartina plantations.

• Tunnel and Underground Space
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• v.20 no.2
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• pp.82-91
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• 2010

Grouting technology is one of the ground improvement methods used in water controlling and reinforcement of rock mass in underground structure construction. It is necessarily required to find out the characteristics of grout flow through discontinuities in a rock mass for an adequate grout design and performance assessment. Laminar flow is not always applicable in simulating a grout flow in a rock mass, since the rock joints usually have apertures at a micro-scale and the flow through these joints is affected by the joint roughness and the velocity profile of the flow changes partially near the roughness. Thus, the influence of joint roughness and aperture on the grout flow in rough rock joint was numerically investigated in this study. The commercial computational fluid dynamics code, FLUENT, was applied for this purpose. The computed results by embedded Herschel-Bulkley model and VOF (volume of fluid) model, which are applicable to simulate grout flow in a narrow rock joint that is filled with air and water, were well compared with that of analytical results and previously published laboratory test for the verification. The injection pressure required to keep constant injection rate of grout was calculated in a variety of Joint Roughness Coefficient (JRC) and aperture conditions, and the effect of joint roughness and aperture on grout flow were quantified.

• Research in Plant Disease
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• v.12 no.2
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• pp.144-147
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• 2006

Egg yolk immunoglobulin (IgY) is much widely used in medical fields, but its use in serology of plant viruses is much limited. We produced an IgY against pepper mild mottle virus (PMMoV) and applied it to several serological tests. Polyclonal antibodies were obtained from the egg yolk of chicken immunized with a total of 2mg of purified PMMoV over 2 months. The titers of antibodies were measured with the ring-test over six months after the first injection. The highest.titers of IgY was 1/2,560 at 2 months after the first injection. Approximately 60-80 mg of IgY were obtained from one egg yolk. Using the IgY, 1ng/ml of purified PMMoV was detected with the indirect ELISA. Gelrite gel double diffusion test, ELISA and tissue immuno-binding assay employing IgY gave similar sensitivity and specificity to those of IgG developed in rabbit. Therefore, the IgY which can be obtained in large quantities from a chicken, might be useful for the antibody production and the serology of plant viruses.

• Journal of Life Science
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• v.18 no.4
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• pp.550-555
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• 2008

This study focused on alcohol fermentation properties of red ginseng extracts using Saccharomyces cerevisiae JF-Y3. Central composite design was employed to investigate the influence of red ginseng extract content ($10{\sim}50%$, v/v) and yeast extract ($0.5{\sim}2.5%$, w/v) on the properties of alcohol fermentation added with red ginseng extracts. Yeast cell growth was affected both by red ginseng extract content and yeast extract content, and red ginseng extract content had a greater effect on yeast cell number than yeast extract content. Yeast cell number increased along with decrease of the red ginseng extract content and with increase of yeast extract content. Alcohol content was maximal at 30% red ginseng extracts and 0.50% yeast extract and the predicted maximum value of alcohol content was 12.45%. Brix degree and total sugar content were significant within 1% level (p<0.01), and brix degree was affected both by red ginseng extract and yeast extract content. Total sugar content was significantly affected by red ginseng content.

• Journal of Life Science
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• v.18 no.4
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• pp.556-564
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• 2008

Response surface methodology was used to monitor the optimization of fermentation conditions for red ginseng wine. A central composite design was applied to investigate the effects of independent variables, fermentation temperature ($X_1$), fermentation time ($X_2$) and initial pH ($X_3$) on dependent variables, physicochemical characteristics and effective ingredients. Alcohol and total sugar content were significantly affected both by fermentation temperature and time. Crude saponin content was greatly affected by fermentation time, and pH was significantly affected by initial pH. Fermentation time and initial pH had a greater effect on ginsenoside content than fermentation temperature. Ginsenoside content increased along with fermentation time and initial pH. We elicited a regression formula for each variable, and superimposed the total optimum points of fermentation conditions for physicochemical characteristics and the effective constituents. The predicted values at the optimum fermentation conditions were at $21{\sim}27^{\circ}C$ for $15{\sim}20$ day in initial pH $4.6{\sim}5.2$.

• Education of Primary School Mathematics
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• v.18 no.3
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• pp.235-247
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• 2015

This study analyzed what STEAM elements, except mathematical content, are contained in 2009 revised elementary school 3rd and 4th grade group mathematics textbooks. STEAM elements in the textbooks were examined by grade and by content area in the elementary school mathematics curriculum. According to the results, the difference between 3rd and 4th grade in the number of STEAM elements is almost not visible. Distribution of specific content areas could be seen that the distribution STEAM element is similar to the percentage distribution of the content area. However, the number of STEAM elements are different depending on the type of STEAM. The number of arts element is 448(67.6%) and this elements are seen the most. The number of representative art and cultural art is 344(51.9%) and 104(15.7%), respectively. The number of technology-engineering and science is 160(24.1%) and 55(8.3%), respectively. We need to developed to promote use of science element in next mathematics curriculum.

• Journal of the Korean Society for Nondestructive Testing
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• v.36 no.1
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• pp.18-26
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• 2016

The semiconductor industry is one of the key industries of Korea, which has continued growing at a steady annual growth rate. Important technology for the semiconductor industry is high integration of devices. This is to increase the memory capacity for unit area, of which key is photolithography. The photolithography refers to a technique for printing the shadow of light lit on the mask surface on to wafer, which is the most important process in a semiconductor manufacturing process. In this study, the width and step-height of wafers patterned through this process were measured to ensure uniformity. The widths and inter-plate heights of the specimens patterned using photolithography were measured using transmissive digital holography. A transmissive digital holographic interferometer was configured, and nine arbitrary points were set on the specimens as measured points. The measurement of each point was compared with the measurements performed using a commercial device called scanning electron microscope (SEM) and Alpha Step. Transmission digital holography requires a short measurement time, which is an advantage compared to other techniques. Furthermore, it uses magnification lenses, allowing the flexibility of changing between high and low magnifications. The test results confirmed that transmissive digital holography is a useful technique for measuring patterns printed using photolithography.

• Journal of the Korean Society for Nondestructive Testing
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• v.36 no.3
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• pp.195-201
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• 2016

Eddy current testing (ECT) is commonly applied for the inspection of automated production lines of metallic products, because it has a high inspection speed and a reasonable price. When ECT is applied for the inspection of a metallic object having an uneven target surface, such as the spline gear of a spline shaft, it is difficult to distinguish between the original signal obtained from the sensor and the signal generated by a defect because of the relatively large surface signals having similar frequency distributions. To facilitate the detection of defect signals from the spline gear, implementation of high-order filters is essential, so that the fault signals can be distinguished from the surrounding noise signals, and simultaneously, the pass-band of the filter can be adjusted according to the status of each production line and the object to be inspected. We will examine the infinite impulse filters (IIR filters) available for implementing an advanced filter for ECT, and attempt to detect the flaw signals through optimization of system design parameters for detecting the signals at the system level.