• 한국전기전자재료학회논문지
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• 제20권1호
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• pp.86-91
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• 2007

Contact material is widely used as electrical parts. Ag-CdO has a good wear resistance and stable contact resistance. But the disadvantages of Ag-Cd alloy are coarse Cd oxides and harmful metal, Cd. Then Ag-Sn alloy that has stable and fine Sn oxide at high temperature has been developed. In order to investigate the effect of Te additional that affects the formation of the oxide layer on the surface and the formation of oxide in matrix Ag, we studied the microstructures and properties of Ag-Sn-In(-Te) material fabricated by rapid solidification process. The experimental procedure were melting using high frequency induction, melt spinning, and internal oxidation. Specimens were examined and analyzed by Transmission electron microscopy(TEM), energy dispersive X-ray spectroscopy(EDS) and Vickers hardness. As a result, internal oxidation was completed even at $600^{\circ}C$. Te forms coarse $In_{2}TeO_{6}$ phase and makes fine and well dispersed $SnO_{2}$ Phase. 0.3 wt% Te shows favorable properties.

• Geomechanics and Engineering
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• 제7권3호
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• pp.297-316
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• 2014

This paper presents a detailed study focused on investigating the effects of silt content on the static and dynamic properties of sand-silt mixtures. Specimens with a low-plastic silt content of 0, 15, 30 and 50% by weight were tested in static triaxial, cyclic triaxial, and resonant columns in addition to consolidation tests to determine such parameters as compression index, internal friction angle, cohesion, cyclic stress ratio, maximum shear modulus, normalized shear modulus and damping ratio. The test procedures were performed on specimens of three cases: constant void ratio index, e = 0.582; same peak deviator stress of 290 kPa; and constant relative density, $D_r$ = 30%. The test results obtained for both the constant-void-ratio-index and constant-relative-density specimens showed that as silt content increased, the internal friction angle, cyclic stress ratio and maximum shear modulus decreased, but cohesion increased. In testing of the same deviator stress specimens, both cohesion and internal friction angle were insignificantly altered with the increase in silt content. In addition, as silt content increased, the maximum shear modulus increased. The cyclic stress ratio first decreased as silt content increased to reach the threshold silt content and increased thereafter with further increases in silt content. Furthermore, the damping ratio was investigated based on different silt contents in three types of specimens.

• Parasites, Hosts and Diseases
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• 제52권1호
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• pp.117-120
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• 2014

Several studies have reported that the citrus red mites Panonychus citri were an important allergen of citrus-cultivating farmers in Jeju Island. The aim of the present study was to purify and assess properties of a cysteine protease from the mites acting as a potentially pathogenic factor to citrus-cultivating farmers. A cysteine protease was purified using column chromatography of Mono Q anion exchanger and Superdex 200 HR gel filtration. It was estimated to be 46 kDa by gel filtration column chromatography and consisted of 2 polypeptides, at least. Cysteine protease inhibitors, such as trans poxy-succinyl-L-leucyl-amido (4-guanidino) butane (E-64) and iodoacetic acid (IAA) totally inhibited the enzyme activities, whereas serine or metalloprotease inhibitors did not affect the activities. In addition, the purified enzyme degraded human IgG, collagen, and fibronectin, but not egg albumin. From these results, the cysteine protease of the mites might be involved in the pathogenesis such as tissue destruction and penetration instead of nutrient digestion.

• Macromolecular Research
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• 제11권2호
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• pp.104-109
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• 2003

A microcellular, which combines a rubber with the conventional formulation of styrene/divinylbenzene/sorbitan monooleate/water system, was prepared using high internal phase emulsion (HIPE) polymerization. Although the open microcellular foam with low density from the conventional HIPE polymerization shows highly porous characteristics with fine, regular and isotropic structure, the one having much smaller cell size is desirable for various applications. In this study, a polybutadiene was introduced to reduce the cell size with comparable properties. Major interests were focused on the effects of rubber concentration and agitation speed on the cell sizes and compression properties. Scanning electron microscopy was used to observe the microcellular morphology and compression tests were conducted to evaluate the stress-strain behaviors. It was found that the cell size decreased as rubber concentration increased, reflecting a competition between the higher viscosity of continuous phase and the lower viscosity ratio of dispersed to continuous phases due to the addition of high molecular weight rubber into the oil phase of emulsion. A correlation for the average cell size depending on agitation speed was attempted and the result was quite satisfactory.

• Journal of Ginseng Research
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• 제22권2호
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• pp.96-101
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• 1998

This paper describes the determination of bulk density and the discrimination of internal structure of red ginseng by nuclear magnetic resonance (NMR). The 102 red ginseng roots were tested for bulk density. The NMR properties measured by NMR parameters such as spin-lattice relaxation time ($T_1$) and spin-spin relaxation time ($T_2$) were determined using the low field proton NMR analyzer. Bulk density of red ginseng root showed a highly negative significant correlation (r=-0.8934) with the value of $T_1$, but a highly positive significant correlation (r=0.7672 and 0.5909) with the value of T21 (short T2) and T22 (long T2), respectively. Multiple regression equation, Y=-0.0069.$T_1$+0.3044.$T_{21}$-0.0156.$T_{22}$-0.6368, using the MNR parameter values of 80 red ginseng roots can effectively predict the bulk density of 22 red ginseng roots with the correlation coefficient of 0.9396 and the standard error of 0.086. The differences in the internal structure of normal and inside white part of red ginseng were easily found by the signal intensity of NMR image based on magnetic properties of proton nucleus.

• 대한한방내과학회지
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• 제24권2호
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• pp.233-248
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• 2003

Objectives : This research examined about dietary therapy on the gastric & duodenal ulcer based on the literary findings, for clinical treatment and prevention of the gastric & duodenal ulcer. Methods : This Research examined on histories, compositions, applications, and effects of dietetic on about 200 cases of dietary therapy of the gastric & duodenal ulcer from recent Chinese literatures Results : 1. Various vegetables, animals and mineral materials including herbs, grains, vegetables, fruits, food and drink were used for the dietary therapy. 2. Methods of the preparation for use as therapeutics were decoction, pulvis, gruel, medicinal wine, cake, tea, paste and gelatin and etc. 3. Frequently used materials were cuttle fish bone, Bletillae rhizoma, oyster shell, egg shell, sugar, aloe, licorice, lily, red jujube, and pig stomach. 4. Four properties of cold, warm, cool and hot were equal in frequencies. Most common tastes were sweet and bitter. Conclusion : Though dietary therapy for the gastric & duodenal ulcer is not based on clinical or experimental data, but through experience. It is mostly based on Yin-Yang and five elements, visceral manifestation, channels and their collateral channels and chinese herbal medicine theories. If we use them properly according to oriental medicine method, it will be effective on treating and preventing the gastric & duodenal ulcer.

• 설비공학논문집
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• 제29권3호
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• pp.97-104
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• 2017

Reinforcement of insulation in apartment buildings reduces the heating and cooling energy consumption by lowering the heat transfer in the building envelope. There are differences between internal and external insulation methods in heat transmission properties. However, some building load calculation programs cannot analysis the differences between the two. This is because these programs do no account for the timelag or thermal storage effect of the wall according to the location of insulation. In this study, the heat transmission characteristics of internal and external insulation were analyzed by EnergyPlus, and heating and cooling energy demand was compared. The results showed that external insulation system had lower heating and cooling loads than internal insulation system. Also the heat transfer rate of external insulation is steadier than internal insulation. About 13.6% of heating and cooling energy demand decreased when the outdoor wall was finished with external insulation compared to the demand with internal insulation.

• 대한치료과학회지
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• 제10권2호
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• pp.21-30
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• 2018

Objective: The purpose of this study was to investigate questions and instructions for internal feedback effects on functional recovery and task performance while chronic stroke patients practised task-specific training. Method: Twenty-four chronic stroke patients were randomly divided into two groups; when patients performed same tasks, one was treated using questions and the other using instructions for internal feedback Both lasted 30 minutes, 5 times a week for 8 weeks. Outcome measures included Erasmus MC Modifications to the Nottingham Sensory Assessment (EmNSA), Measurement Properties of the Motor Evaluation Scale for Upper Extremity in Stroke patients (MESUPES), Chedoke Arm and Hand Activity Inventory (CAHAI), Korean version of Modified Barthel Index (K-MBI). Results: There were no significant differences between the two groups in EmNSA and K-MBI(p>.05). But, in MESUPES and CAHAI, there was significant difference between the two groups(p<.05). Conclusion: In this study, questions for internal feedback during task-specific training are more effective in improving upper extremity motor function and task performance than instructions for internal feedback.

• 한국결정성장학회:학술대회논문집
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• 한국결정성장학회 2000년도 Proceedings of 2000 International Nano Crystals/Ceramics Forum and International Symposium on Intermaterials
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• pp.243-248
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• 2000

Effect of NiO addition on microstructure, stability of tetragonal phase and mechanical properties was investigated. (Y, Ni)-TZP solid solution was obtained by pressureless sintering. The fracture toughness was increased by solid solution of NiO. Neither reaction phase nor glassy phase was observed at the grain boundaries. From these results, it was determined that solid solution of NiO was destabilized tetragonal phase of Y-TZP. Y-TZP/Ni nanocomposite that contained nano-sized Ni particles was also fabricated by internal reduction method. Some evaluations and discussions were carried out for both (Y, Ni)-TZP solid solution and Y-TZP/Ni nanocomposite.

• Geomechanics and Engineering
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• 제22권2호
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• pp.165-171
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• 2020

Laboratory determination of strength and deformation behavior of clean sands and gravels has always been challenging due to the difficulty in obtaining their undisturbed samples. An alternative solution to this problem is to develop correlations between mechanical properties of cohesionless soils and their gradation characteristics. This study presents database of 3 natural sands with 11 varying particle size gradation curves to allow investigating relationships between mean particle size, maximum and minimum void ratio, relative density and shear strength of the test soils. Direct shear tests were performed at relative densities of 50, 75 and 95% to explore the effects of gradation and density on the angle of internal friction of the modeled sand samples. It is found that the mean grain size D₅₀ bears good correlations with void ratio range (e_max - e_min) and peak angle of internal friction 𝜙'_peak. The generated regression models are in good agreement with published literature and can be considered as reliable for natural sands in Pakistan. These empirical correlations can save considerable time and efforts involved in laboratory and field testing.