• Journal of the korean academy of Pediatric Dentistry
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• v.30 no.1
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• pp.25-32
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• 2003

S. mutans is the most important causative bacteria of dental caries among the oral bacteria. S. salivarius is a normal inhabitant in the human oral cavity. Nine strains of S. salivarius in this study were isolated from the oral cavities of children and identified, and their effect on S. mutans and S. oralis was studied. 1. The mean weight of produced artificial plaque on the wires in the beaker was 204.9 mg in the culture of S. mutans only, whereas being reduced to 1.9 mg through 20.6mg in the combined culture of S. mutans and each S. salivarius isolate (p<0.05). The viable cell didn't show the difference between them after culturing. 2. When S. mutans was cultured in the media containing culture supernatant of each S. salivarius isolate in M17 broth, the mean weight of produced artificial plaque was 117.1 mg on the wires, whereas being 47.7 mg in the media containing culture supernatant of each S. salivarius isolate in M17 broth containing 5% sucrose. 3. The polymer produced by S. salivarius isolates was on the thin layer chromatography. 4. Inulin and levan didn't inhibit the formation of artificial plaque by S. mutans in the beaker test. These results suggested that fructan-producing S. salivarius isolates inhibited the formation of artificial plaque by S. mutans.

• Journal of the Korean Geosynthetics Society
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• v.16 no.4
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• pp.231-240
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• 2017

Recently, there have been frequent occurrences of ground sink in the urban area, which have resulted in human and material damage and are accompanied by economic losses. This is caused by artificial factors such as soil loss, poor compaction, horizontal excavation due to the breakage of the aged sewage pipe, and lack of water proof at vertical excavation. The ground sink can be prevented by preliminary restoration and reinforcement through exploration, but it can be considered that it is not suitable for urgent restoration by the existing method. In this study, a model experiment was carried out to simulate the in-ground cavities caused by groundwater flow for developing non-excavation urgent restoration in underground cavity and the range of the relaxation zone was estimated by detecting the around the cavity using a relaxation zone detector. In addition, disturbance region and relaxation region were separated by injecting gypsum into cavity formed in simulated ground. The shape of the underground cavity due to the groundwater flow was similar to that of the failure mode III formed in the dense relative density ground due to water pipe breakage in the previous study. It was confirmed that the relaxed region detected using the relaxation zone detector is formed in an arch shape in the cavity top. The length ratio of the relaxation region to the disturbance region in the upper part of the cavity center is 2: 1, and it can be distinguished by the difference in the decrease of the shear resistance against the external force. In other words, it was confirmed that the secondary damage should not occur in consideration of the expandability of the material used as the injecting material in the pre-repair and reinforcement, and various ground deformation states will be additionally performed through additional experiments.

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.172-172
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• 2006

Molecular imprinting constitutes a valuable method of preparing polymeric materials with specific binding properties. The most conspicuous merit of molecular imprinting is that structurally three-dimensional recognition sites can be introduced into a polymer matrix with ease and low cost when compared with the complicated process of biological system for antigen and antibody. We used a thermally reversible bond for the preparation of the monomer-template complex, which allowed us to remove the template easily by means of a simple thermal reaction and to simultaneously introduce various functional groups into the cavity. This method is especially propitious for developing artificial receptors for molecules lacking strongly interactive groups.

• Journal of electromagnetic engineering and science
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• v.9 no.4
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• pp.211-217
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• 2009

A three-dimensional locally one-dimensional multiresolution time-domain(LOD-MRTD) method is introduced and unconditional stability is proved analytically. The updating formulations have fewer terms on the right-hand side than those of an alternating direction implicit MRTD(ADI-MRTD). The validation of the method is presented using the resonance frequency problem of an empty cavity. The reduction of the numerical dispersion technique is also combined with the proposed method. The numerical examples show that the combined method can improve the accuracy significantly.

• Journal of the Korean Society of Visualization
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• v.2 no.2
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• pp.3-7
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• 2004

In this paper, computational aeroacoustics (CAA) method is used for flow-noise analysis and flow-noise visualization. High order high resolution scheme of optimized high order compact is used to resolve the small acoustic quantities and large flow quantities at the same time. An adaptive nonlinear artificial dissipation model and generalized characteristic boundary condition are also used. Aeolion tone noise, cavity noise, and jet noise are investigated. The visualizations of flow-noise are successful and characteristics of noise are studied. It is observed that the propagation directivity of noise is different with that of flow. With the help of CAA method, the visualization of noise is possible.

• Journal of Veterinary Clinics
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• v.9 no.2
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• pp.451-456
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• 1992

The 2% Sodium carboxymethylcellulose(CMC) and 10% Dextran 70 solutions were evaluated for the prevention of postoperative adhesion formation in rats. The artificial injuries(2cm longitudinal incision and suture) were performed on the colon and uterine horns in the rats. 2% CMC and 10% dextran solutions were applied to the injured surfaces and peritoneal cavity in the rats. Ten days later, there were significant difference(p<0.01) in the prevention of adhesion formation between control and treated groups(2% CMC and 10% dextran 70), but the,$\boxUl$ was no significant difference between 2% CMC and 10% dextran 70 treated groups. The increment rate of body weight in the 10% dextran 70 treated group was lower than 2% CMC and control groups(p<0.05.). A positive correlation was found between the severity of adhesion formation and the plasma fibrinogen concentration in blood.

• Journal of Yeungnam Medical Science
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• v.37 no.3
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• pp.169-178
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• 2020

Glass ionomer cement (GIC) is a tailor-made material that is used as a filling material in dentistry. GIC is cured by an acid-base reaction consisting of a glass filler and ionic polymers. When the glass filler and ionic polymers are mixed, ionic bonds of the material itself are formed. In addition, the extra polymer anion reacts with calcium in enamel or dentin to increase adhesion to the tooth tissue. GICs are widely used as adhesives for artificial crowns or orthodontic brackets, and are also used as tooth repair material, cavity liner, and filling materials. In this review, the current status of GIC research and development and its prospects for the future have been discussed in detail.

• 한국생물공학회:학술대회논문집
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• 2002.04a
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• pp.139-144
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• 2002

Two types of alginate gel beads capable of floating in the gastric cavity were prepared. The first, alginate gell bead containing olive oil(Al-Oil), is a hydrogel bead and its buoyancy is attributable to olive oil held in the alginate gel matrix. The model drug, metronidazole(MZ), contained in Al-Oil was released gradually into artificial gastric fluid. The profiles of MZ release from Al-Oil shown initial burst and after 90 min they were about 100%. The second, alginate gel bead containing curdlan microsphere(Al-C), is a gel bead with curdlan-MZ microsphere in the matrix. To sustained release rate of drug, alginate bead were prepared curdlan microsphere containing MZ. Results demonstrated that sustained delivery of MZ over 2h can be easily achieved while the bead remained float. The release properties of prepared alginate beads are applicable not only for sustained release of drugs but also for targeting the gastric mucosa.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.04b
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• pp.198-203
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• 1995

In the paper, we have proposed a new technique to detemine the initial billet for the forged products using a function approximation in neural network. A three-layer neural network is used and a back propagation algorithm is employed totrain the network. An optimal billet which satisfied the forming limitation, minimum of incomplete filling in the die cavity, load and energyas well as more uniform distribution of effective strain, is determined by applying the ability of function approximation of te neural network. The amount of incomplete filling in the die, load and forming energyas well as effective strain are measured by the rigid-plastic finite element method. The new technique is applied tofind the optimal billet size for the axisymmetric rib-web product in hot forging. This would reduce the number of finite element simulation for determing the optimal billet of forging products, further it is usefully adapted to physical modeling for the forging design.

• Proceedings of the Korean Society of Embryo Transfer Conference
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• 2006.10a
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• pp.84-85
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• 2006