• Journal of Wetlands Research
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• v.23 no.3
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• pp.234-241
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• 2021

This paper contributes to the understanding of the effect of pulley on the performance of the vortex turbine in free water surface. The experimental work was to analyze the rotation, voltage and current of the turbine due to physical factors (vortex height, velocity, effective head, etc.) at flow rates ranging from 0.0069 to 0.0077 m³/s in the inlet channel. As a result, the experimental values showed that voltage, current and rotational speed of the vortex turbine decreased with increasing the pulley ratio regardless of the blade type. The efficiency of straight blade and twisted blade was 52 % at the gear ratio of 0.45, whereas the efficiency of small twisted blade was 54 % at the pulley ratio of 0.21. The highest amount of the energy generated by the water free vortex turbine occurred within a pulley ratio of 0.5. The efficiency of this vortex turbine was observed at 0.2 ~ 58 % depending on the pulley ratio.

• Journal of Wetlands Research
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• v.25 no.3
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• pp.176-183
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• 2023

The aim of this paper is to understand the blade number effect on vortex turbine performance in the cylindrical vortex chamber below the free water surface. Using the same blade profile, the performance of gravitational vortex turbine is tested each with 2, 3, 4, 5 and 6 blades installed at the relative vortex height (y/h_v) ranging from 0.065 to 0.417. The obtained results indicate that the rotation, voltage, current and power increase in the relative vortex height of 0.065 and 0.111 when increasing the number of blades at flow velocity of less than 0.7 m/s. The average power of the 5-blade turbine is more than others. The performance of the 4-blade turbine with a 130 mm diameter installed near the orifice is higher than that of the same number of blades with a 220 mm diameter in the vortex chamber.

• Textile Coloration and Finishing
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• v.35 no.4
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• pp.239-245
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• 2023

Cellulose is an abundant biodegradable material in nature with excellent properties, but due to its poor processability, it has been widely studied for processing through modification. Cellulose acetate propionate (CAP) is a cellulose derivative in which the hydroxyl group of cellulose is replaced by acetyl and propionyl groups. CAP has several advantages, such as excellent solubility, structural stability, light and weather resistance, and good transparency. Porous nanofibers with excellent specific surface area, which can be applied in various fields, can be easily formed by the phase separation method using highly volatile solvents. High speed centrifugal spinning is a nano/micro fiber preparation method with advantages such as fast spinning and easy alignment control. In this study, a CAP/polybutylene succinate (PBS) spinning solution with chloroform as solvent was prepared to prepare porous microfibers and the fiber morphology was examined as a function of the disk rotation speed in an high speed centrifugal spinning device.

• Progress in Medical Physics
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• v.19 no.2
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• pp.102-112
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• 2008

We developed a high-resolution micro-CT system based on rotational gantry and flat-panel detector for live mouse imaging. This system is composed primarily of an x-ray source with micro-focal spot size, a CMOS (complementary metal oxide semiconductor) flat panel detector coupled with Csl (TI) (thallium-doped cesium iodide) scintillator, a linearly moving couch, a rotational gantry coupled with positioning encoder, and a parallel processing system for image data. This system was designed to be of the gantry-rotation type which has several advantages in obtaining CT images of live mice, namely, the relative ease of minimizing the motion artifact of the mice and the capability of administering respiratory anesthesia during scanning. We evaluated the spatial resolution, image contrast, and uniformity of the CT system using CT phantoms. As the results, the spatial resolution of the system was approximately the 11.3 cycles/mm at 10% of the MTF curve, and the radiation dose to the mice was 81.5 mGy. The minimal resolving contrast was found to be less than 46 CT numbers on low-contrast phantom imaging test. We found that the image non-uniformity was approximately 70 CT numbers at a voxel size of ${\sim}55{\times}55{\times}X100\;{\mu}^3$. We present the image test results of the skull and lung, and body of the live mice.

• Progress in Medical Physics
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• v.23 no.3
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• pp.127-137
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• 2012

A conversing beam is firstly designed for radiosurgery by a neurosugern Lars Leksell in 1949 with orthogonal x-rays tube moving through horizontal moving arc to focusing the beam at target center. After 2 decades he composits 201 source of the Co-60 for gamma knife which beams focused at locus. Sveral linac-based stereotactic radiosurgery using the circular collimated beam which size range for 0.4~4.0 cm in a diameter by non-coplanar multiarc have been developed over the decades. The irregular lesions can be treated by superimposing with several spherical shots of radiation over the tumour volume. Linac based techniques include the use of between 4 and 11 non-co-planar arcs and a dynamic rotation technique and use photon beam energies in the range of 6~10 MV. Reviews of the characteristics of several treatment techniques can be found in the literature (Podgorsak 1989, Schell 1991). More in recent, static conformal beams defined by custom shaped collimators or a mini- or micro-multileaf collimator (mMLC) have been used in SRS. Finally, in the last few years, intensity-modulated mMLC SRS has also been introduced. Today, many commercial and in-house SRS programs have also introduced non-invasive immobilization systems include the cyberknife and tomotherapy and proton beam. This document will be compared the characteristics of dose distribution of radiosurgery as introduced gamma knife, BrainLab include photon knife in-house SRS program and cyberknife in currently wide used for a cranial SRS.

• Spatial Information Research
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• v.22 no.2
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• pp.53-62
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• 2014

The floor field model is the micro pedestrian model based on a cellular automata for modeling pedestrian movement in the interior space using the static and dynamic floor field. It regards a form of pedestrian as square but the actual pedestrian's shape and size are similar to ellipsoid or rectangle. Because of this, we are difficult to give a rotation effect to pedestrians and there is a limit to reflect an impact of clogging and jamming. Also, this model is not able to reflect an impact of a posture and visibility effectively in the pedestrian movement. In this study, we suggest the improved pedestrian model incorporating the actual shape and size of pedestrian. The pedestrian's shape is defined not square but rectangle which is close to the actual body size of Korean. Also, we define the model which is able to represent the impact of clogging and jamming between pedestrians by adding the pedestrian's posture. We develop the simulator for testing the suggested model and study the difference between two models by comparing a number of effects. As a result, we could confirm solving the problem with dynamic value in the existed model and reflecting the panic effect in evacuation situation.

• Journal of the Korean Magnetics Society
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• v.23 no.6
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• pp.193-199
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• 2013

The regional distribution of magnetic isotropy depending on the post annealing condition for the dual-type structure GMR-SV (giant magnetoresistance-spin valve) of NiFe/Cu/NiFe/IrMn/NiFe/Cu/NiFe multilayer was investigated. The rotation of in-plane ferromagnetic layer induced by controlment of the post annealing temperature inside of the vacuum chamber. The magnetoresistive curves of a dual-type IrMn based GMR-SV depending on the direction of the magnetization easy axis of the free layer and the pinned layer are measured by between $0^{\circ}$ and $360^{\circ}$ angles for the applied fields. The optimum annealing temperature having a steady and isotropy magnetic sensitivity of 1.52 %/Oe was $107^{\circ}C$ in the rotational section of $0{\sim}90^{\circ}$. By investigating the switching process of magnetization for an arbitrary measuring direction, the in-plane orthogonal magnetization for the dual-type GMR-SV multilayer can be used by a high sensitive biosensor for detection of magnetized micro-beads.

• Korean Journal of Soil Science and Fertilizer
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• v.25 no.1
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• pp.70-76
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• 1992

A field experiment was conducted to find out the influence of cropping systems under rotation of paddy-upland soil on soil microorganisms with specific reference to cations concentration in the soil. The results obtained was summarized as follows. 1. The number of soil bacteria and actinomycetes increased in fallow, continuous cultivation of rice and soybean while the number of fungi decreased. 2. Gram negative bacteria as Pseudomonas spp. and Rhizobium spp. remarkably incerased with increasing Gram positive bacteria of Bacillus subtilis in continuous cultivatio of soybean. 3. The relative population of soil born plant pathogen such as Fusarium spp. Rhizoctionia spp. and Phoma spp. to the total soil fungi was high in cultivation of potato and Chinese cabbage. The ratio of soil plant pathogen to the total soil fungi was high in cultivation of potato with Chinese cabbage. 4. The number of bacteria and actinomycetes was positively correlated with ratio of Ca＋Mg/K in soil while negatively correlated with soil fungi.

• Restorative Dentistry and Endodontics
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• v.33 no.4
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• pp.323-331
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• 2008

Flexibility and fracture properties determine the performance of NiTi rotary instruments. The purpose of this study was to evaluate how geometrical differences between three NiTi instruments affect the deformation and stress distributions under bending and torsional conditions using finite element analysis. Three NiTi files (ProFile .06 / #30, F3 of ProTaper and ProTaper Universal) were scanned using a Micro-CT. The obtained structural geometries were meshed with linear, eight-noded hexahedral elements. The mechanical behavior (deformation and von Mises equivalent stress) of the three endodontic instruments were analyzed under four bending and rotational conditions using ABAQUS finite element analysis software. The nonlinear mechanical behavior of the NiTi was taken into account. The U-shaped cross sectional geometry of ProFile showed the highest flexibility of the three file models. The ProTaper, which has a convex triangular cross-section, was the most stiff file model. For the same deflection, the ProTaper required more force to reach the same deflection as the other models, and needed more torque than other models for the same amount of rotation. The highest von Mises stress value was found at the groove area in the cross-section of the ProTaper Universal. Under torsion, all files showed highest stresses at their groove area. The ProFile showed highest von Mises stress value under the same torsional moment while the ProTaper Universal showed the highest value under same rotational angle.

• The Journal of Korea Assosiation for Disability and Oral Health
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• v.15 no.1
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• pp.84-88
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• 2019

Malocclusion occurs more frequently in Special Health Care Needed (SHCN) patients than those in general. As caregiver's needs for orthodontic treatment tend to increase, the dentist should know how to decide the extent of treatment. This case report is about orthodontic treatment for two SHCN patients; one patient with cerebral palsy, and another patient with autism. A 10-year-old patient with cerebral palsy showed protrusion and rotation of maxillary anterior teeth. To resolve his chief complaints and make better oral hygiene, he underwent orthodontic treatment using micro tube appliances for 6 months. Another 11-year-old patient with autism had anterior crossbite and showed space deficiency of #13 and chronic gingivitis because of poor oral hygiene. She underwent orthodontic treatment with maxillary skeletal expander, facemask and AP expansion appliance. After 18 months we found positive overjet and ended the treatment. When giving SHCNs orthodontic treatment, the extent of treatment can be chosen according to the patient's cooperative ability and the traits of disabilities. Before initiating orthodontic treatment, the caregivers should be aware of their limitations of the treatment. Since oral hygiene is crucial factor in every dental treatment, education of oral hygiene process for the caregivers and SHCN patient must be done before the orthodontic treatment.