• The Journal of Korean Academy of Prosthodontics
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• v.42 no.5
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• pp.597-607
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• 2004

Purpose: This study was peformed to investigate the retrievability of the cemented crown from the cementation type implant abutment. Material and method: The cementation type implant abutments (NEOBIOTECH implant abutment regular, 3 degree taper, 10mm length, 4mm diameter, Ti grade III, machined surface. Hwasung, Kyunggi-do) and cemented crowns were divided into 3 groups, depending on their hole angles formed in the crowns for their retrievability. The abutments and crowns were luted with 4 kinds of cements and separation test using metal wedge was executed with Instron 4465 Universal Testing Machine and the maximum impact force of the modified crown ejector was measured. Results and conclusion : 1. All of the cementation type implant abutments and cemented crowns were separated with relatively small force by metal wedge. 2. The retrieving force was minimum when the metal wedge was applied perpendicular to the axis of abutment. 3. The force for retrieving crowns from abutments was maximum in resin cement group, and reduced in orders of zinc phosphate cement, glass ionomer cement and zinc oxide eugenol cement. 4. The maximum force obtained by the crown ejector was higher than the retrieval force in ZOE and GI cement and lower than that in ZPC and resin cement. 5. If it has similar conditions clinically, the cemented crowns luted with 2 types of cements (ZOE, GI cement) can be safely retrieved from the cementation type implant abutments by the modified crown ejector.

• Journal of the Korean GEO-environmental Society
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• v.15 no.9
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• pp.59-67
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• 2014

With increasing underwater structure construction, there is high interest in offshore foundation and underwater grout and various study has been done in this area. For grout materials constructed underwater, it may be washed away by water or easily disturbed and material separation phenomenon during curing period always happens. As a result, it is difficult to ensure construction quality and this has a significant influence on the design strength of structure. In this study, to understand application effects of anti-washout admixture for the preplaced construction method, where grout is injected in monopile after filled with aggregates, laboratory tests on bleeding and compressive strength of anti-washout admixture were performed under various test conditions varying size of aggregate, water and cement ratio and admixture, and test results were compared and evaluated.

• Journal of the Korean Applied Science and Technology
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• v.29 no.1
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• pp.122-128
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• 2012

The influences of fluorescence, scattering, and flocculation in turbid material by light scattering of L-aspartic acid, preservative and emulsifier were interpreted for the scattered fluorescence intensity and wavelength. They have been studied the molecular properties by the spectroscopy of laser induced fluorescence (LIF) and flocculation. The effects of optical properties in scattering media have been found by the optical parameters(${\mu}_s$, ${\mu}_a$, ${\mu}_t$). Flocculation is an important step in many solid-liquid separation processes and is widely used. When two particles approach each other, interactions of several colloid particles can come into play which may have major effect on the flocculation and LIF process. The values of scattering coefficient ${\mu}_s$ are large by means of the increasing scattering of scatterer, The values have been found that the slope decays exponentially as a function of concentration from laser source to detector by our experimental result. It may also aid in designing the best model for oil chemistry, bio-pharmaceutical products, laser medicine and application of medical engineering on LIF and coagulation in particle transport mode.

• Journal of the Korean Applied Science and Technology
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• v.31 no.2
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• pp.167-175
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• 2014

The influences of fluorescence, scattering, and flocculation in turbid material were interpreted for the scattered fluorescence intensity and wavelength, it has been studied the molecular properties by the spectroscopy of laser induced fluorescence(LIF). The effects of optical properties in scattering media have been found by the optical parameters(${\mu}_s$, ${\mu}_a$, ${\mu}_t$). Flocculation is an important step in many solid-liquid separation processes and is widely used in Photodynamic therapy. The interactions of several colloid particles can come into play which have major effect on the flocculation and LIF process. We measured scattering and fluorescence spectra of the sample for in vitro as function of concentration from lase source to detector. The value of scattering coefficient ${\mu}_s$ is large by means of the increasing particles of scatterer. Therefore, Phorphyrin A is larger than Phorphyrin C in scattering intensity ${\mu}_s$, but Phorphyrin A is smaller than Phorphyrin C in penetration depth ${\delta}$.

• Asian-Australasian Journal of Animal Sciences
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• v.5 no.2
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• pp.249-256
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• 1992

Italian ryegrass (Lolium multiflorum Lam.) was fractionated into leaf nutrient concentrate, fiber and deproteinised juice (DPJ). The fresh and fermented DPJs were concentrated and referred to as fresh deproteinised juice concentrate (FDPJC) and fermented deprotenised juice concentrate (FMTD DPJC). The FDPJC and FMTD DPJC were separately mixed with dried fiber and ensiled. Wilted crop silage and fresh fiber silage were also prepared from the same material crop. The nutritive value of these four silages were compared using four goats by $4{\times}4$ Latin square design. Green crop fractionation resulted lesser amount of crude protein and ash, and higher amount of neurtal detergent fiber, acid detergent fiber, cellulose and hemicellulose in fresh fiber. The pH of fresh fiber silage was lower than that of the other silages. Addition of FDPJC or FMTD DPJC to the dried fiber at ensiling did not improve the silage qualities; but all the silages were satisfactorily preserved. Goats fed these silages showed similar ruminal pH and total volatile fatty acid concentrations. But addition of FMTD DPJC was effective on increasing ruminal acetic acid concentration reducing propionic acid concentration. Ruminal n- and iso- butyric acid concentrations were proportional to that of propionic acid. High ammonia content of the silage containing FMTD DPJC was reflected to the ruminal ammonia concentration, urinary nitrogen excretion and serum urea level of goats. Inclusion of FDPJC or FMTD DPJC added 15 to 25% dry matter to the fiber silages with a little reduction in the digestibilities of most components of the silages.

• Clinics in Shoulder and Elbow
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• v.13 no.2
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• pp.266-269
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• 2010

Purpose: We report case of neglected elbow dislocation for three years. Material and method: A 45 years old female patient presented with neglected elbow dislocation for three years. Since the patient had contracture in both lateral and medial collateral ligament of elbow, dissection was done. After total separation of posterior articular capsule and incision of anterior articular capsule, by manual manipulation, reduction of radiohumeral and ulnohumeral joints were obtained. We applied modified Morrey type hinged external fixation in the elbow and done early elbow exercise. Result and Conclusion: Since we have experienced a satisfactory result in the case with neglected elbow dislocation for 3 years by using open reduction and hinged external fixation, we report it with the literature.

• Applied Biological Chemistry
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• v.6
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• pp.33-36
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• 1965

1. The extraction of securine, an alkaloid, from Securinega suffruticosa Rehder growing in Korea was investigated. 2. The distribution of the source plant in Korea is considered to be most intense among the Fareast countries. 3. The extracted material was identified to be genuine securinine viewing from melting point and microscopic observation. 4. The yield of the substance in this study was 0.075% in average. The less amount of recovery may be due to the collection of the plant in October instead of that in the prime season. 5. There should be more efficient way in the separation of resinous impurities from the crude product. Application of Chromatographic technique and selection of more efficient solvent will be investigated hereafter.

• Economic and Environmental Geology
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• v.18 no.3
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• pp.239-246
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• 1985

Uranium-thorium separation technique from shallow sediment and ${\alpha}$-source electrodeposition technique are established in the present work, and uranium series disequilibrium dating method is applied to the quaternary piston core from Sangback-do, South Sea of Korean Peninsula. The age of the piston core (depth 200~300cm) sampled from Latitude $34^{\circ}06^{\prime}37^{{\prime}{\prime}}$, Longitude $127^{\circ}37^{\prime}37^{{\prime}{\prime}}$ was determined as ranging from $9.0{\pm}2.2$ to $22.9{\pm}3.3$ Ky B.P, i.e., Later Pleistocene, older than Holocene which was stratigraphically known in the previous study. The sedimentation rate in the area is regularly increased according to the depth of the sedimentation layer. Except a few split sections of the piston core the sedimentation rates are avarage 7.2cm/1,000 years. Where sedimentation layer is deeper, then sedimentation rate tend to be slower. It must be pointed in age calculation that initial $^{230}Th/^{234}U$ radioactivity ratio is much influenced when detrital material was introduced in the sample. The $^{230}Th/^{234}U$ activity ratio measured in the present work is 0.06 at $^{232}Th=0$, and this value shows higher analytical errors because of the low· radioactivity of $^{230}Th$ in the samples.

• Applied Chemistry for Engineering
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• v.7 no.3
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• pp.410-415
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• 1996

It is well known that the heavy water separation process using hydrogen isotope exchange reaction over the platinum catalyst is the most efficient. In this study, the Pt/silicalite catalysts were prepared and characterized by hydrogen adsorption in order to develop the hydrophobic platinum catalyst for hydrogen isotope exchange reaction. Silicalite was synthesized as support material and it was verified that silicalite is more hydrophobic than activated carbon and ZSM-5. Also the platinum was loaded on silicalite by conventional impregnation and ion-exchange method respectively. The platinum dispersion of Pt/silicalite catalysts was measured through hydrogen adsorption experiment. The dispersion is very low in the catalyst prepared by the impregnation method while it is very high with limited platinum content in the catalyst prepared by the ion-exchange method.

• Nuclear Engineering and Technology
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• v.41 no.7
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• pp.875-884
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• 2009

We present three nuclear/hydrogen-related R&D activities being performed at KAIST: air-ingressed LOCA analysis code development, gas turbine analysis tool development, and hydrogen-production system analysis model development. The ICE numerical technique widely used for the safety analysis of water-reactors is successfully implemented into GAMMA, with which we solve the basic equations for continuity, momentum conservation, energy conservation of the gas mixture, and mass conservation of 6 species (He, N2, O2, CO, CO2, and H2O). GAMMA has been extensively validated using data from 14 test facilities. We developed a tool to predict the characteristics of HTGR helium turbines based on the throughflow calculation with a Newton-Raphson method that overcomes the weakness of the conventional method based on the successive iteration scheme. It is found that the current method reaches stable and quick convergence even under the off-normal condition with the same degree of accuracy. The dynamic equations for the distillation column of HI process are described with 4 material components involved in the HI process: H2O, HI, I2, H2. For the HI process we improved the Neumann model based on the NRTL (Non-Random Two-Liquid) model. The improved Neumann model predicted a total pressure with 8.6% maximum relative deviation from the data and 2.5% mean relative deviation, and liquid-liquid-separation with 9.52% maximum relative deviation from the data.