• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.11a
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• pp.633-636
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• 2004

Acoustic response control of a corner-pinned plate using piezoelectric wafers was studied, both theoretically and experimentally. Three different sizes of aluminum alloy plates were used and available ball joints were employed to hold the plate at the four comers. The plate with the largest aspect ratio showed the largest and most clear responses to the acoustic excitation in the range of frequencies $(0\sim200Hz)$, and sound pressure levels $(80\sim100dB)$ as predicted. The reduction of the acoustic response of the plate by piezoelectric actuator was very significant, more than expected, but abatement of the sound transmission through the plate was only slightly altered by the piezoelectric actuator. This work is an original work extending earlier work with doors excited by acoustic fields. The important difference is the used of ball joints to simulate the joints.

• Dementia and Neurocognitive Disorders
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• v.17 no.4
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• pp.131-136
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• 2018

Alzheimer's disease (AD) related genes have been elucidated by advanced genetic techniques. Familial autosomal dominant AD genes founded by linkage analyses are APP, PSEN1, PSEN2, ABCA7, and SORL1. Genome-wide association studies have found risk genes such as ABCA7, BIN1, CASS4, CD33, CD2AP, CELF1, CLU, CR1, DSG2, EPHA1, FERMT2, HLA-DRB5-HLA-DRB1, INPP5D, MEF2C, MS4A6A/MS4A4E, NME8, PICALM, PTK2B, SLC24A4, SORL1, and ZCWPW1. ABCA7, SORL1, TREM2, and APOE are proved to have high odds ratio (>2) in risk of AD using next generation sequencing studies. Thanks to the promising genetic techniques such as CRISPR-CAS9 and single-cell RNA sequencing opened a new era in genetics. CRISPR-CAS9 can directly link genetic knowledge to future treatment. Single-cell RNA sequencing are providing useful information on cell biology and pathogenesis of diverse diseases.

• Bulletin of the Korean Chemical Society
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• v.15 no.12
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• pp.1038-1042
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• 1994

The amperometric responses of thiourea were studied in 0.1 M NaOH by flow injection analysis. D. C. amperometric and pulsed amperometric detection methods were applied for the determination of thiourea at novel metal electrodes such as Pt and Au. Triple-step potential waveforms were adopted in the pulsed amperometric detection. With an optimized pulsed waveform, the current for the oxidation of thiourea was examined with the variation of flow rate of carrier solution and with the change in the amount of sample injected. Gold working electrode turned out to be better in sensitivity and signal to noise ratio than Pt electrode in the pulsed amperometric detection of thiourea. Detection limit is estimated to be 5.33 ${\times}$ 10$^{-5}$ M with this detection method.

• Journal of the Korean Magnetics Society
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• v.5 no.5
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• pp.623-626
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• 1995

High coercivity thin $Fe_{3}O_{4}$ and ${\gamma}-Fe_{2}O_{3}$ films were deposited on Si substrate under well controlled $O_{2}$ partial pressure by dcreactive magnetron sputtering. The coercivity of as-deposited maggnetite films is below 640 Oe. After cxidizing at $360^{\circ}C$ for 10 minutes, the films transform to maghemite ${\gamma}-Fe_{2}O_{3}$ completely, and the coercivity increases greatly to 2100~4120 Oe, depending on modification of not with minor addition of Co or/and Mn. The orign of coercivity enhancement is attributed mainly to magnetic anisotropy arisen from interfacial stress. The addition of 5 at% Co and 5 at% Mn greatly enhances coercivity and squareness ratio. These films are potential for ultra-high density recording applications.

• Textile Coloration and Finishing
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• v.33 no.3
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• pp.113-119
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• 2021

Polypropylene fiber has the advantages of light weight, heat retention and antibacterial properties, but it is difficult to expand its market because it cannot be dyed or imparted functionality due to its hydrophobic properties. Atmospheric pressure plasma processing can modify the surface of the fiber and create polar functional groups on the surface of the fiber. In this study, an experiment was conducted on the hydrophilization of the ultra-hydrophobicity of polypropylene through plasma processing and surface changes before and after plasma processing. The ultra-hydrophobicity of polypropylene is the cause of impossible for dyeing and imparting functionality. Untreated polypropylene became hydrophilic, and it was confirmed that the ratio of oxygen and carbon(O/C) increased about 11 times from untreated polypropylene 0.017 to plasma-treated polypropylene 0.190.

• Current Applied Physics
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• v.18 no.12
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• pp.1553-1557
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• 2018

Gallium nitride (GaN) nanoparticles are synthesized by the gallium particle trapping effect in a $N_2$ nonthermal plasma with metallic Ga vapor. A proposed method has an advantage of synthesized GaN nanoparticle purity because the gallium vapor from the inductively heated tungsten boat does not contain any impurity source. The synthesized particle size can be controlled by the amount of Ga vapor, which is adjusted using the plasma emission ratio of nitrogen to gallium, owing to the particle trapping effect. The synthesized nanoparticles are investigated by electron microscopy studies. High-resolution transmission electron microscopy (HRTEM) studies confirm that the synthesized GaN nanoparticles (10-40 nm) crystallize in a single-phase wurtzite structure. Room-temperature photoluminescence (PL) measurements indicate the band-edge emission of GaN at around 378 nm without yellow emission, which implies that the synthesized GaN nanoparticles have high crystallinity.

• Journal of Korea Port Economic Association
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• v.37 no.1
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• pp.1-18
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• 2021

A coastal marine ranching project in Uleungdo had been conducted for 5 years from 2013 to 2017 with investment costs of 5 billion won, for the special purpose of the deployment of artificial reefs, the release of young fishes. The paper focuses on an ex-post analysis of the economic feasibility for the project after completing the project, which is apart from a preliminary viability. For economic analysis, the economic benefits are derived from direct benefits including increasing effects of fisheries income and saving effects of harvesting costs, and indirect benefits including increasing effects of recreational fishing and preservation effects of coastal marine ecosystems while economic costs include releasing and purchasing costs of artificial reef and juvenile fish, R&D costs, maintenance costs and harvesting costs. The result shows that the project should not be accepted according to NPV=-0.125 billion won, IRR=4.5% and B/C ratio=0.98 under Scenario 1 which considers direct benefits and indirect benefits excluding the preservation values, while the project should be accepted under Scenario 2 indicating NPV=30.9 billion won, IRR=11.3% and B/C ratio=1.49 which considers the direct benefits as well as the indirect ones including the preservation values, based on 4.5% of the social rate of discount.

• Journal of The Korean Society of Grassland and Forage Science
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• v.22 no.2
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• pp.107-114
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• 2002

Rice straw silage added with apple pomace in different ratios were mixed with commercial concentrates and fed to Korean native goats in comparison to the corn silage mixed with the same content of commercial concentrates in whole diet as that of apple pomace added rice straw silage (rice straw : apple pomace = 100:0, 80:20, 60:40, 40:60). Dry matter intake, digestibilities of nutrients and nitrogen retention were investigated for the possibilities of application of agricultural by-products for the diets of Korean native goats. Crude protein contents of rice straw silage added with apple pomace were 6.3~7.3% and the contents of ADF, NDF and crude ash were highest in 100% rice straw mixed ratio (A) as 39.4, 61.6 and 8.9% respectively. Those were lower in corn silage (E) as 30.3, 53.4 and 4.9% respectively, however NSC content of corn silage was highest among the experimental treatments as 31.4%. Daily dry matter intakes per head and also per metabolic basal weight (DM g/kg of $BW^{0.75}$ were significantly (p<0.05) higher in D of the highest mixed ratio of apple pomace (605.3, 69.5g) than those of corn silage (E: 394.0, 46.8g). Daily live weight changes were significantly (p<0.05) higher in 40% (C: 16.7g) and 60% (D: 22.9g) apple pomace mixed ratios than 0% (A: 0.17g) and 20% (B: 4.3g) apple pomace mixed ratios. Digestibilities of dry matter and organic matter were higher in D and E than in A and B and those of ADF and NDF were higher in D as 50.2 and 57.4% respectively than the digestibilities in A, B and E. Nitrogen retention (g, %) was highest in D of the highest mixed apple pomace ratio (1.4g, 20.4%) however lowest in A (-0.3g, -7.75%).

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.27 no.4
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• pp.278-285
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• 1991

The authors propose to use the slot system in order to improve of the efficiency for the cambered otter boards. The experiment is divided into 2 parts, one is the efficiency model test, and the other is the visualization model test. The hydrodynamic characteristics of the model otter boards were tested by efficiency model test to measure the shearing, drag force of the models and visualization test using hydrogen bubble method to observe the streak-line and time-line of flow around the models, and milk spout method to observe the separation zone in the wake behind the models. This study tested for 5 models such ad without slot, slot position 0.2C, 0.4C, 0.6C and 0.8C. The results obtained are as follows: \circled1 The maximum C sub(L) of model otter board with slot position 0.6C in attack angle 27$^{\circ}$ was the highest of all models, it's value was 1.59. \circled2 In general, the L/D ratio of the one slot otter boards were 16~28% higher than otter board without slot. \circled3 The slot position 0.6C was better than any other slot position, and it's conformed by visiualization. \circled4 As to the model otter board with slot position 0.6C, flow speed of the back side was faster 1.3 to 1.7 times than in the front side. \circled5 The size of the separated zone in case of the model otter board with 0.6C was smaller than that of any other models.

• Asian-Australasian Journal of Animal Sciences
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• v.26 no.2
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• pp.227-232
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• 2013

Phytate is not only an unavailable source of phosphorus (P) for broilers but it also acts as an anti-nutrient, reducing protein and mineral absorption, increasing endogenous losses and reducing broiler performance. The objective of this study was to investigate the anti-nutritional effects of phytate by including high levels of phytase in diets not severely limited in available P. A total of 768 male Arbor Acres broilers were distributed in six treatments of eight replicate pens of 16 birds each consisting of a positive control diet (PC), positive control with 500 FTU/kg phytase, negative control (NC) diet with lower available P and calcium (Ca) levels and the same NC diet with 500, 1,000 or 1,500 FTU/kg phytase. Body weight gain (BWG), feed intake (FI), feed conversion ratio (FCR) and mortality were determined at 21 and 35 d of age while foot ash was determined in four birds per pen at 21 d of age. FI, FCR and foot ash where not affected by the lower mineral diets at 21 d of age nor by the enzyme inclusion but broilers fed lower Ca and available P diets had lower BWG. At 35 d of age no difference was observed between broilers fed the positive or NC diets but broilers fed 500, 1,000 and 1,500 FTU/kg on top of the NC diet had better FCR than broilers fed the positive control diet. When compared to birds fed a diet adequate in P, birds fed the same diet included with 500, 1,000 and 1,500 FTU/kg of phytase in marginally deficient available P and Ca diets had an improvement of performance. These results support the concept that hydrolysing phytate and reducing the anti-nutritional effects of phytate improves bird performance on marginally deficient diets that were not covering the P requirement of birds.