• 한국결정성장학회지
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• 제29권6호
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• pp.365-371
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• 2019

본 연구에서 SiO₂ 증착용 확산 화염 버너의 연료와 산소의 비율 변화에 따른 화염의 온도 분포를 전산 유체 해석을 수행하였다. 이는 친환경 원료물질을 이용한 광섬유 제조용 SiO₂ 프리폼 증착 공정을 시뮬레이션하기 위한 전단계에 해당한다. 예혼합 연소를 모델링하기 위해서 열 유동, 대류 및 화학 반응을 고려하였고 Reynolds-averaged Navier-Stokes 방정식과 k-ω 모델을 사용하였으며, 실제 화염의 온도 분포와 형상을 비교하여 연소 모델링의 적절성을 확인하였다. 결과적으로 화염의 온도 분포는 보조 산소의 유량이 증가하면 노즐 표면으로부터 최고 온도까지의 거리가 증가하는 경향성을 보였다. 또한 혼합 가스의 당량비가 큰 연소 반응에서 불완전 연소로 인한 온도 분포의 폭이 크게 나타나는 것을 확인하였다.

• Asian-Australasian Journal of Animal Sciences
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• 제11권6호
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• pp.697-701
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• 1998

In order to improve silage quality and utilization of napier grass (Pennisetum purpureum Schum.) by goats, the grass was ensiled with molasses (MOL) and/or defatted rice bran (DRB). Napier grass was harvested at the growing stage in July and cut into 3 cm length. The grass was mixed with 4% MOL and/or 15% DRB, ensiled 15 kg each into plastic bags and stored for 9 months. Dry matter content of the silage ensiled with MOL (MOL-silage) was 13.4%, but increased to 20% with DRB addition. The addition of MOL decreased pH value and ammonia nitrogen content, but increased lactic acid content. MOL-silage contained about 6% spoilage, but addition of DRB decreased spoilage to less than 1%. Goats were fed the silage at a level of 2.25% (DM basis) of their body weight. Goats fed DRB- or MOL/DRB-silages maintained nitrogen retention, but goats fed MOL-silage did not. The rumen fluid of goats fed DRB-silage tended to be higher in acetic acid and lower in propionic acid than those fed the other silages. Ammonia in the rumen fluids, urea nitrogen in the blood and the urinary nitrogen excretion were the lowest in goats fed MOL/DRB-silage. As the result, the ratio of retained nitrogen to nitrogen intake was the highest in goats fed MOL/DRB-silage. In conclusion, addition of DRB to napier grass increased DM of silage and decreased the volume of spoilage. The combination of MOL and DRB can improve the fermentation quality and thus enhance the utilization of the silage by goats, more than the MOL or DRB being as a single treatment.

• Composites Research
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• 제30권1호
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• pp.41-45
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• 2017

Magnetite nanoparticles were synthesized by adding an ammonium hydroxide to a mixed solution of iron (II) and (III) chlorides. A silicon surfactant of ${\alpha},{\omega}$-(3-aminopropyl)polydimethylsiloxane was adsorbed on the particles as dispersant and a polydimethylsiloxane polymer was used to prepare ferrofluids of silicone oil base. Fluorinated surfactants of anionic ammoniated perfluoroalkyl sulfonamide and nonionic fluoroaliphatic polymeric esters were applied to the particles and a perfluoropolyether was used to prepare ferrofluids of fluorine oil base. The experimental conditions were used for preparing the ferrofluids with concentrations of 200, 300 and 400 mg/mL, and density, magnetization and viscosity of the products were characterized. The density values increased in proportion to the concentration, indicating 1.11-1.27 g/mL for silicone-oil-based fluids and 1.95-2.10 g/mL for fluorine-oil-based fluids in the range of 200-400 mg/mL. The saturation magnetization of the silicone-oil-based and fluorine-oil-based fluids indicated 14.7, 24.4, and 30.7 mT and 15.8, 23.3, and 33.7 mT for 200, 300, and 400 mg/mL, respectively, depending on the content of magnetic particles in the fluid. The viscosity of the silicone-oil-based ferrofluids was highly stable compared to that of the fluorine-oil-based with increasing temperatures. The ferrofluids are usually applied to seals and speakers with the silicone base and to seals with the fluorine base.

• Asian-Australasian Journal of Animal Sciences
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• 제22권2호
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• pp.201-205
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• 2009

Effects of Cordyceps militaris mycelia on rumen microbial fermentation were determined by measuring in vitro gas production, cellulose digestion and VFA concentrations. C. militaris mycelia was added to buffered rumen fluid with final concentrations of 0.00, 0.10, 0.15, 0.20, 0.25 and 0.30 g/L and incubation times were for 3, 6, 9, 12, 24, 36, 48 and 72 h. At all incubation times, the gas production showed a quadratic increase with the supplementation of C. militaris mycelia; maximum responses were seen with 0.25 g/L supplementation. However, the gas production was significantly lower for the 0.30 g/L supplementation than for the 0.25 g/L supplementation from 9 h to 72 h incubation. The cellulose filter paper (FP) digestion showed a quadratic increase, as did the gas production except at 3 h incubation. The concentration of total VFA was significantly increased by the supplementation of C. militaris mycelia compared with the control treatment; the highest response was also seen with 0.25 g/L supplementation. This was true for responses in the concentration of acetic and propionic acids. As opposed to other responses, the responses of pH to the supplementation of C. militaris mycelia showed a quadratic decrease from 3 h to 36 h incubation. In conclusion, C. militaris mycelia alter the mixed rumen microbial fermentation with increases in the production of gas and VFA, and cellulose FP digestion.

• Asian-Australasian Journal of Animal Sciences
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• 제24권3호
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• pp.364-368
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• 2011

An experiment was conducted to examine the effects of Cordyceps militaris mycelia on microbial populations and fibrolytic enzyme activities in vitro. C. militaris mycelia was added to buffered rumen fluid with final concentrations of 0.00, 0.10, 0.15, 0.20, 0.25 and 0.30 g/L and incubation times were for 3, 6, 9, 12, 24, 36, 48 and 72 h. At all incubation times, the supplementation of C. militaris mycelia linearly increased the number of total viable and celluloytic bacteria; maximum responses were seen with 0.25 g/L supplementation of C. militaris mycelia. The addition of C. militaris mycelia above the level of 0.20 g/L significantly (p<0.01) increased the number of total and cellulolytic bacteria compared with the control. On the other hand, the response of fungal counts to the supplementation of C. militaris mycelia showed a linear decrease; the lowest response was seen with 0.30 g/L supplementation of C. militaris mycelia. It would seem that C. militaris mycelia possess a strong negative effect on rumen fungi since the lowest level of C. militaris mycelia supplementation markedly decreased fungal counts. Carboxylmethyl cellulase activities were linearly increased by the addition of C. militaris mycelia except at 3 and 9 h incubation times. At all incubation times, the supplementation of C. militaris mycelia linearly increased the activities of xylanase and avicelase. In conclusion, the supplementation of C. militaris mycelia to the culture of mixed rumen microorganisms showed a positive effect on cellulolytic bacteria and cellulolytic enzyme activities but a negative effect on fungi.

• 한국기계가공학회지
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• 제17권4호
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• pp.39-46
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• 2018

Two surfaces that have relative motion show different characteristics according to surface roughness or surface patterns in all lubrication areas. For two rough surfaces with mixed lubrication, this paper proposes a new approach that includes the contact characteristics of the surfaces and a probabilistic method for a numerical analysis of lubrication. As the contact area of the two surfaces changes according to the loading conditions, asperity contact is very important. An average flow model developed by Patir-Cheng is central to the study of lubrication for rough surfaces. This average flow model also refers to a multi-asperity contact model for deriving a modified Reynolds equation and calculating the lubricant characteristics of a bearing surface with random roughness during fluid flow. Based on the average flow model, this paper carried out a numerical analysis of lubrication using a contact model by considering a load change made by the actual contact of asperities between two surfaces. Lubrication properties show different characteristics according to the surface patterns. This study modeled various geometric surface patterns and calculated the characteristics of lubrication.

• 한국실내디자인학회논문집
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• 제22권1호
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• pp.115-123
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• 2013

Today, the views on Temporality of space have been changed not only to be based on the concept of time, but also to identify the space with a body adapted to the new circumstances. The study suggests that the actions of performers in space have been important by changes of views and are connected to the music phenomenology mixed with music whose tempo is the phenomenology related with of human consciousness itself, and derives the temporal property by putting them into Rem Koolhaas space with the fluid quality. According to Clifton's Phenomenology of Music, an understanding of music is made in both human body and consciousness as two ways to listen to sounds and enjoy music. Though a correlation between the characteristics of Clifton's Phenomenology of Music and one of resulted from uncertainty and immateriality of modern space Temporality, we could work out four kinds of characters which are the continuity of the fluidity from temporal programs, contrasting changes or synchronicity, the multidimensionality from synesthesia of line and face, ventilation by quality of the material and immaterial circumstances of sound effects, the implication in events resulted from cognition for information and unexpected actions, and the autonomy of the route of a variety of experiences including intimate connection of inter-related events and temporary and diverse external conditions. Hereby Temporality of musical phenomenology in Rem Koolhaas's space can be experienced by systems base oh the importance of host's motion, changes of programs according to the motion as well as uncertainty and immaterial changes. Due to the changes user's emotion and motion is undergone as Temporality that changes automatically.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2017년도 춘계학술대회 논문집
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• pp.156-156
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• 2017

In this work, analysis of biocompatible TiO2 oxide multilayer by the XPS depth profiling was researched. the manufacture of the TiO2 barrier-type multilayer was accurately performed in a mixed electrolyte containing HAp, Pd, and Ag nanoparticles. The temperature of the solution was kept at approximatively $32^{\circ}C$ and was regularly rotated by a magnetic stirring rod in order to increase the ionic diffusion rate. The manufactured specimens were carefully analyzed by XPS depth profile to investigate the result of chemical bonding behaviors. From the analysis of chemical states of the TiO2 oxide multilayer using XPS, the peaks are showed with the typical signal of Ti oxide at 459.1 eV and 464.8 eV, due to Ti 2p(3/2) and Ti 2p(1/2), respectively. The Pd-3d peak was split into Pd-3d(5/2) and Pd-3d(3/2)peaks, and shows two bands at 334.7 and 339.9 eV for Pd-3d3 and Pd-3d5, respectively. Also, the peaks of Ag-3d have been investigated. The chemical states consisted of the O-1s, P-2p, and Ti-2p were identified in the forms of PO42- and PO43-. Based on the results of the chemical states, the chemical elements into the TiO2 oxide multilayer were also inferred to be penetrated from the electrolyte during anodic process.The structure characterization of the modified surface were performed by using FE-SEM, and from the result of biological evaluation in simulated body fluid(SBF), the biocompatibility of TiO2 oxide multilayer was effective for bioactive property.

• 한국임상수의학회지
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• 제30권4호
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• pp.310-314
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• 2013

12년령 암컷 혼혈견이 외음부에 돌출된 질 종양으로 내원하였다. 이 환자는 정상적으로 변과 오줌을 배출하였고 임신 경험은 없었다. 혈청생화학적인 소견상 질소혈증, 경미한 고나트륨 혈증과 alkaline phosphatase 값의 상승이 있었다. 혈액학적 검사 소견은 정상이었다. 초음파 검사에서 좌 우측 자궁각의 내강에 존재하는 액체로 인하여 무에코성에서 저에코성으로 나타났고 심하게 종대되어 있었다. 또한, 우측 난관의 종양 내에 국소적으로 저에코성 영역이 나타났다. 컴퓨터단층촬영에서는 우측 난소낭, 액체로 인해 확장된 자궁, 확장된 질과 질의 종양이 관찰되었다. 본 환자에 대해 난소자궁적출술과 회음부 절개술을 통한 종양절제술을 실시하여 난관과 질에 존재하는 종양을 제거하였다. 본 환자는 난관 선암종, 질 섬유종, 자궁축농증이 병발한 첫 번째 사례로 여겨진다.

• Biomolecules & Therapeutics
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• 제4권4호
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• pp.419-427
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• 1996

To solubilize practically insoluble biphenyl dimethyl dicarboxylate (DDB), which has been used for the treatment of chronic hepatitis as tablets or hard capsules, the solubilities of DDB in various hydrophilic, oily and hydrocarbon vehicles, and aqueous surfactant solutions were measured by high performance liquid chromatography. It was found that, among the vehicles studied, polyethylene glycol (PEG) 300 revealed the best solvency, and the solubility reached 17.6 mg/ml at 37$^{\circ}C$. The addition of glycyrrhizic acid ammonium salt (GAA) to DDB-PEG 300 solution (5-20 mg/g) inhibited the formation of precipitates, and at the concentration of 10 mg/g, any precipitaction was not observed even after 2 years at 4$^{\circ}C$. Furthermore, GAA markedly enhanced the permeation of DDB through the rabbit duodenal mucosa in a concentration dependent manner. The addition of copolyvidone (ca. 1.0%) to DDB-GAA-PEG 300 system (1 : 0.5 97.5 w/w) was most effective in preventing the considerable precipitation of DDB-PEG 300 solution (7.5 mg/750 mg) when mixed with water of 300-900 ml at 37$^{\circ}C$. GAA showed a synergistic effect in the prevention of precipitate formation. This finding suggests that this DDB formulation may form less precipitation when DDB soft capsules disintegrate and diffuse into the gastrointestinal fluid, resulting in improving the bioavailability Dissolution rate of DDB (7.5 mg) from sort elastic capsules of DDB-GAA-PEG 300 system was rapid. The supersaturation state was maintained for 2 hr at the concentration of 7.35$\pm$3.3 mg in 900 ml of water without precipitation. The total amount of DDB dissolved from this new formulation was 5.3 and 6.1 times higher, when compared to marketed DDB tablets (25 mg) and capsules (7.5 mg), respectively.