• FLOWER RESEARCH JOURNAL
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• v.17 no.3
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• pp.185-189
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• 2009

This study was carried out to investigate the effect of shading (50% or not) and pruning height (3cm, 6cm, and 9cm) of remained above-ground plant part on shoot emergence aspect, mortality rate, flowering and cut flower characteristics of two years old Gypsophila paniculata plants. Days to shoot emergence (80%) advanced, emerged shoot number increased and mortality rate surveyed on late October decreased in 50% shading treatment. In addition to, mortality rate decreased, as above-ground plant part was highly pruned. Blooming was earlier with highly pruning the remained above-ground pan and under non-shading condition than shading. Growth traits such flower stalk length, primary branches number, stem diameter, and cut flower yield were the best and also non-particulate rate and rosette formation rate were the lowest in pruning height of 9cm under non-shading condition.

• Journal of Periodontal and Implant Science
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• v.53 no.3
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• pp.207-217
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• 2023

Purpose: Non-crosslinked and crosslinked collagen membranes are known to exhibit distinct degradation characteristics, resulting in contrasting orientations of the adjacent tissues and different biological processes. The aim of this study was to conduct a histomorphometric assessment of non-crosslinked and crosslinked collagen membranes regarding neovascularization, tissue integration, tissue encapsulation, and biodegradation. Methods: Guided bone regeneration was performed using either a non-crosslinked (BG) or a crosslinked collagen membrane (CM) in 15 beagle dogs, which were euthanized at 4, 8, and 16 weeks (n=5 each) for histomorphometric analysis. The samples were assessed regarding neovascularization, tissue integration, encapsulation, the remaining membrane area, and pseudoperiosteum formation. The BG and CM groups were compared at different time periods using nonparametric statistical methods. Results: The remaining membrane area of CM was significantly greater than that of BG at 16 weeks; however, there were no significant differences at 4 and 8 weeks. Conversely, the neovascularization score for CM was significantly less than that for BG at 16 weeks. BG exhibited significantly greater tissue integration and encapsulation scores than CM at all time periods, apart from encapsulation at 16 weeks. Pseudoperiosteum formation was observed in the BG group at 16 weeks. Conclusions: Although BG membranes were more rapidly biodegraded than CM membranes, they were gradually replaced by connective tissue with complete integration and maturation of the surrounding tissues to form dense periosteum-like connective tissue. Further studies need to be performed to validate the barrier effect of the pseudoperiosteum.

• Journal of Veterinary Clinics
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• v.24 no.3
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• pp.350-357
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• 2007

Bone graft had been widely investigated for reconstruction of bone defects or acceleration of bone healing in orthopedics, neurosurgery and dental surgery. Autograft is the golden standard of bone graft but it is associated with donor site morbidity and is restricted in quantity. Xenograft has been researched an alternative method for autograft. The purpose of this study was to investigate the efficacy of new bone formation according to three different preparations of implants on rabbit xenograft. Cortical bone xenografts which made from bovine femoral cortical bone were treated by freezing, freeze-drying or defat-freezing implant preparations. They were transplanted into proximal diaphyseal shaft of bifibulae of 15 rabbits which were divided into three groups according to their implant preparation method. The fibulae transplantations were evaluated radiographically and examined osteoblast activity by bone alkaline phosphatase (BALP) biweekly for 16 weeks to observe new bone formation and union of the experimental defected region. New bone formation was observed in 7 cases in freeze-drying and defat-freezing group, respectively. Union of proximal and distal end of defected region, which was considered as success of bone graft, was observed in 4 cases (40%; 4 of 10 cases), respectively. In freezing group, new bone formation was observed in 6 cases but, there is no union observed. BALP value was increased over twice after two weeks of graft procedure in all union cases of freeze-drying and defat-freezing group (two of five animals, respectively) then gradually decreased to 16th week. In non-union cases, there is no significant variation in BALP value. Defat-freezing or freeze-drying preparations of implants are more efficacious in new bone formation than freezing method on rabbit xenograft. While it is difficult to propose which is superior between defat-freezing and freeze-drying, defatting of implants may enhance new bone formation in xenograft.

• Clinical and Experimental Reproductive Medicine
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• v.51 no.1
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• pp.57-62
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• 2024

Objective: The purpose of this study was to use a mouse model to investigate the blastocyst formation rate in vitrified-warmed embryos derived from vitrified-warmed oocytes. Methods: Metaphase II oocytes obtained from BDF1 mice were vitrified and warmed, followed by fertilization with epididymal sperm. On day 3, a total of 176 embryos, at either the eight-cell or the morula stage, were vitrified-warmed (representing group 1). For group 2, 155 embryos at the same developmental stages were not vitrified, but rather were directly cultured until day 5. Finally, group 3 included day-5 blastocysts derived from fresh oocytes, which served as fresh controls. The primary outcome measured was the rate of blastocyst formation per day-3 embryo at the eight-cell or morula stage. Results: The rates of blastocyst formation per day-3 embryo were comparable between groups 1 and 2, at 64.5% and 69.7%, respectively (p>0.05). The formation rates of good-quality blastocysts (expanded, hatching, or hatched) were also similar for groups 1 and 2, at 35.5% and 43.2%, respectively (p>0.05). For the fresh oocytes (group 3), the blastocyst formation rate was 75.5%, which was similar to groups 1 and 2. However, the rate of good-quality blastocyst formation in group 3 was 57.3%, significantly exceeding those of group 1 (p=0.001) and group 2 (p=0.023). Conclusion: Regarding developmental potential to the blastocyst stage, vitrified-warmed day-3 embryos originating from vitrified-warmed oocytes demonstrated comparable results to non-vitrified embryos from similar oocytes. These findings indicate that day-3 embryos derived from vitrified-warmed oocytes can be effectively cryopreserved without incurring cellular damage.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1999.10a
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• pp.351-356
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• 1999

In this study, the characteristics of chip formation of the cold drawn Bi-S free machining steels were assessed. And for comparison, those of the cold drawn Pb-S free machining steel, the hot rolled low carbon steel which has MnS as free machining inclusions and the conventional steels were also investigated. During chip formation, the cold drawn free machining steels show relatively little change in thickness and width of chip compare to those of the conventional carbon steels. And a single parameter which indicates the degree of deformation during chip formation, 'chip cross-section area ratio' is introduced. The chip cross-section area. The variational patterns of cross-section area is divided by undeformed chip cross-section area. The variational patterns of the chip cross-section area ratio of the materials cut are similar to those of the shear strain values. The shear stress, however, seems to be dependent on the carbon content of the materials. The cold drawn BiS and Pb-S steels show nearly the same chip forming behaviors and the energy consumed during chip formation is almost same. A low carbon steel without free machining aids shows poor chip breakability due to its high ductility. By introducing a small amount of non-metallic inclusions such as MnS, Bi, Pb or merely increasing carbon content the chip breakability improves significantly.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.37 no.9
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• pp.863-878
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• 2009

Unsteady three-dimensional flowfield generated by transverse fuel injection into a supersonic mainstream is simulated with a DES turbulence model. Comparisons are made with experimental results in terms of the temporal eddy position and eddy formation frequency. The vorticity field around the jet exit is also analyzed to understand the formation mechanism of the large eddy structures. Results indicate that the DES model correctly predicts the convection characteristics of the large scale eddies. However, it is also observed that the numerical results slightly over-predict the eddy formation frequency. The large eddy structures are generated as the counter-rotating vortices are detached alternately in the upstream recirculation region.

• Nuclear Engineering and Technology
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• v.41 no.7
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• pp.929-944
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• 2009

The present study is concerned with the extension of the Effective Convectivity Model (ECM) to the phase-change problem to simulate the dynamics of the melt pool formation in a Light Water Reactor (LWR) lower plenum during hypothetical severe accident progression. The ECM uses heat transfer characteristic velocities to describe turbulent natural convection of a melt pool. The simple approach of the ECM method allows implementing different models of the characteristic velocity in a mushy zone for non-eutectic mixtures. The Phase-change ECM (PECM) was examined using three models of the characteristic velocities in a mushy zone and its performance was compared. The PECM was validated using a dual-tier approach, namely validations against existing experimental data (the SIMECO experiment) and validations against results obtained from Computational Fluid Dynamics (CFD) simulations. The results predicted by the PECM implementing the linear dependency of mushy-zone characteristic velocity on fluid fraction are well agreed with the experimental correlation and CFD simulation results. The PECM was applied to simulation of melt pool formation heat transfer in a Pressurized Water Reactor (PWR) and Boiling Water Reactor (BWR) lower plenum. The study suggests that the PECM is an adequate and effective tool to compute the dynamics of core melt pool formation.

• Journal of Astronomy and Space Sciences
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• v.26 no.1
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• pp.59-74
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• 2009

Relative navigation system is presented using GPS measurements from a single-channel global positioning system (GPS) simulator. The objective of this study is to provide the real-time inter-satellite relative positions as well as absolute positions for two formation flying satellites in low earth orbit. To improve the navigation performance, the absolute states are estimated using ion-free GRAPHIC (group and phase ionospheric correction) pseudo-ranges and the relative states are determined using double differential carrier-phase data and singled-differential C/A code data based on the extended Kalman filter and the unscented Kalman filter. Furthermore, pseudo-relative dynamic model and modified relative measurement model are developed. This modified EKF method prevents non-linearity of the measurement model from degrading precision by applying linearization about absolute navigation solutions not about the priori estimates. The LAMBDA method also has been used to improve the relative navigation performance by fixing ambiguities to integers for precise relative navigation. The software-based simulation has been performed and the steady state accuracies of 1 m and 6 mm ($1{\sigma}$ of 3-dimensional difference errors) are achieved for the absolute and relative navigation using EKF for a short baseline leader/follower formation. In addition, the navigation performances are compared for the EKF and the UKF for 10 hours simulation, and relative position errors are mm-level for the two filters showing the similar trends.

• JSTS:Journal of Semiconductor Technology and Science
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• v.13 no.1
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• pp.22-27
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• 2013

Detailed study on how the plasma process during the sidewall spacer formation suppresses the formation of silicide is done. In non-patterned wafer test, it is found that both fluorocarbon reactive ion etch (RIE) and TEOS plasma-enhanced deposition processes modify the Si surface so that the silicide reaction is chemically inhibited or suppressed. In order to investigate the cause of the chemical modification, we analyze the elements on the silicon surface through Auger Electron Spectroscopy (AES). From the AES result, it is found that the carbon induces chemical modification which blocks the reaction between silicon and nickel. Thus, protecting the surface from the carbon-containing plasma process prior to nickel deposition appears critical in successful silicide formation.

• Journal of The Korean Astronomical Society
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• v.36 no.3
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• pp.105-110
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• 2003

Recent observations of galaxy clusters in radio and X-ray indicate that cosmic rays and magnetic fields may be energetically important in the intracluster medium. According to the estimates based on theses observational studies, the combined pressure of these two components of the intracluster medium may range between $10\%{\~}100\%$ of gas pressure, although their total energy is probably time dependent. Hence, these non-thermal components may have influenced the formation and evolution of cosmic structures, and may provide unique and vital diagnostic information through various radiations emitted via their interactions with surrounding matter and cosmic background photons. We suggest that shock waves associated with cosmic structures, along with individual sources such as active galactic nuclei and radio galaxies, supply the cosmic rays and magnetic fields to the intracluster medium and to surrounding large scale structures. In order to study 1) the properties of cosmic shock waves emerging during the large scale structure formation of the universe, and 2) the dynamical influence of cosmic rays, which were ejected by AGN-like sources into the intracluster medium, on structure formation, we have performed two sets of N-body /hydrodynamic simulations of cosmic structure formation. In this contribution, we report the preliminary results of these simulations.