• Proceedings of the Korea Concrete Institute Conference
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• 2004.05a
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• pp.822-825
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• 2004

Corrosion of reinforced concrete structures in marine environment is one of the most important mechanism of deterioration. The conventional repair techniques of concrete structure damaged by chloride attack consist of removing damaged concrete, cleaning rebar and patching with cement-based materials. However, recently, this method was considered to be ineffective for marine concrete structure in tidal zone. It is necessary to select proper repair method for domestic marine environment which shows broad tidal zone. This paper reports the results of repair of highway concrete bridge damaged by chloride attack in domestic marine environment.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.22 no.12
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• pp.1058-1062
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• 2009

For the investigation of the mechanism of photoelectric characteristics of a hydrogenated amorphous silicon thin film transistor(a-Si:H TFT), spectral characteristics of various backlights were analyzed in terms of the photon energy at each wavelength. Photon energy spectral characteristics were obtained through the multiplication of each photon energy and spectral intensities of backlights at each wavelength and the total photon energies were obtained by the integration of the photon energy spectrums. From the comparison of the experimental photo leakage current and the calculated photon energy, it was possible to conclude that the absorption of illuminated backlight to a-Si:H layer and the generation of electrons and holes are mainly carried out at the wavelength less than 500 nm as described in previous reports.

• Journal of Pharmaceutical Investigation
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• v.2 no.1
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• pp.52-57
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• 1972

There are many reports on the stability of drugs in powders and various dosage forms. The author studied on the stability of ascorbic acid mixed with talcs. From the result of this experiment, it was considered that talcs markedly accelerated oxidative degredation of ascorbic acid in powders and the acceleration rate depends on the varieties of crude talcs. Iron salts seem to be the principal factor influencing the degradation of ascorbic acid Degradation rate of ascorbic acid mixed with purified talc is significantly slower than that with the crnde talcs. The more the concetration of ascorbic acid is diluted, the faster the degradation rate and degredation rate of Ascorbic acid is the function of tme.

• Steel and Composite Structures
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• v.9 no.1
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• pp.77-87
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• 2009

This paper reports the results of an experimental investigation of the polyvinylpyrrolidone (PVP) influence on the steel reinforcement corrosion and compressive strength of concretes in sulphate medium. The effect of admixture of PVP in concrete on the corrosion resistance of steel reinforced concrete was assessed by measuring electrochemical test during 60 days immersion in two different external solutions. AC impedance spectrum indicated that the resistance of PVP mixed electrodes were higher than those without PVP. The compressive strength of concrete specimens containing PVP was measured and an increase of 19%~24% was observed.

• Advances in concrete construction
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• v.5 no.3
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• pp.183-199
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• 2017

This paper reports an experimental study into the rheological behaviour of Smart Dynamic Concrete (SDC). The investigation is aimed at quantifying the effect of the varying amount of mineral admixtures on the rheology, setting time and compressive strength of SDC containing natural sand and crushed sand. Ordinary Portland cement (OPC) in conjunction with the mineral admixtures was used in different replacement ratio keeping the mix paste volume (35%) and water binder ratio (0.4) constant at controlled laboratory atmospheric temperature ($33^{\circ}C$ to $35^{\circ}C$). The results show that the properties and amount of fine aggregate have a strong influence on the admixture demand for similar initial workability, i.e., flow. The large amounts of fines and lower value of fineness modulus (FM) of natural sand primarily increases the yield stress of the SDC. The mineral admixtures at various replacement ratios strongly contribute to the yield stress and plastic viscosity of SDC due to inter particle friction and cohesion.

• The Korean Journal of Pain
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• v.11 no.1
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• pp.150-154
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• 1998

Epidural steroid injection have become one of the most frequently applied conservative option for the management of acute and chronic back pain. As the indications for epidural steroid injections increase so do the adverse responses associated with this procedure. This study reports the succession of 3 patients who developed galactorrhea and hyperprolactinemia after recieving an epidural steroid injection for lumbar radiculopathy and low back pain. Serum prolactin level was elevated in accordance with epidural injection of corticosteroid. We measured the serum prolactin level by immunoradiometric assay method and peak serum prolactin level at above 500, 144.2, 150.3 ng/ml respectively. Also we found the serum prolactin level decreased to normal values 3 wks after corticosteroid injection. Galactorrhra ceased in advance of decrease of serum prolactin level. That "Hyperprolactinemia and galactorrhea can occur following epidural steroid injection", requires a much larger prospective investigation.

• Journal of Pharmaceutical Investigation
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• v.32 no.3
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• pp.181-184
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• 2002

This study reports the encapsulation of plasmid DNA in erythrocyte ghosts. The plasmid DNA was encapsulated into erythrocyte ghosts using three methods; osmotic shock, electroporation in isotonic medium, and e1ectroporation in hypotonic medium. Of three methods, electroporation in hypotonic medium resulted in the highest encapsulation efficiency of plasmid DNA. The morphology of erythrocyte ghosts prepared by electroporation in hypotonic medium was similar to that by osmotic shock alone. The circulation time of plasmid DNA in mice was prolonged by administration in erythrocyte ghost-encapsulated forms. These results indicated the potential of erythrocyte ghosts for biocompative nonviral delivery system of therapeutic genes for hematological diseases.

• Journal of Pharmaceutical Investigation
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• v.3 no.1_2
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• pp.34-50
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• 1973

There are many reports on the stability of drugs in powders and tablets. The stabilities of ascorbic acid in the antacid preparations, such as calcium carbonate, magnesium carbonate, magnesium trisilicate, magnesium alumino silicate, and dried aluminum hydroxide gel under various humidities were examined. From the result of the experiment, it was assumed that the concentration of ascorbic acid, the amount of water-vapor sorption, and the physical character of the antacid ingredients were the main factors, influencing the degradation of ascorbic acid. The ascorbic acid, mixed with carbonates, such as calcium carbonate, was degradaded rapidly, while the preparation with dried aluminum hydroxide gel was slightly degraded after 10 days. A 2% ascorbic acid in the prepation was rapidly degraded than 10% ascorbic acid in the preparation.

• Journal of the Korean Society for information Management
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• v.4 no.2
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• pp.62-83
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• 1987

This paper reports investigation of informal communication among Korean biological scientists. Scientists at the research front communicate informally each other and social organization based upon this communication relation is identified. Seventy-four percent of the scientists are joined together in a large communication network which includes all of the most productive and communicative scientists. Central scientists are the nodal points for dissemination of information as well as important information sources.

• Proceedings of the Materials Research Society of Korea Conference
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• 1992.05a
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• pp.14-14
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• 1992

During the past five years a very successful effort has been made to improve existing and develop new aluminium alloys. The progress achieved has been possible because of the development of new production methods, such as powder metallurgy and spray/deposition. These methods make use of rapid solidification process which alloys compositions other than those achieved by conventional ingot metallurgy. The ingot metallurgy of the 2000 and 7000 series used thus far, as well as the age hardening Al-Li alloys, show several disadvantages caused by the production process. Such problems are primarily coarse intermetallic constituent phases, coarse grains and macrosegregation, resulting in low fracture toughness. The present contribution reports results of an experimental investigation performed on a modern high strength spay deposited aluminium alloy of the Al-Zn-Mg-Cu (7075 and the modified 7150X) type. Results are given in terms of its microstructural characterization by using X-ray diffractomertry and transmission electron microscopic. The mechanical propierties of those alloys in the as-extruded and extruded+aged condition were evaluated by using microhardness Vickers, tensile test and fracture toughness measurements.