• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.26 no.3
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• pp.171-176
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• 2013

In this paper, we present a MEMS (micro-electro-mechanical system) implantable blood pressure sensor which has designed and fabricated with consideration of size, design flexibility, and wireless detection. Mechanical and electrical characterizations of the sensor were obtained by mathematical analysis and computer aided simulation. The sensor is composed of two coils and a air gap capacitor formed by separation of the coils. Therefore, the sensor produces its resonant frequency which is changed by external pressure variation. This frequency movement is detected by inductive coupling between the sensor and an external antenna coil. Theoretically analyzed resonant frequency of the sensor under 760 mmHg was calculated to 269.556 MHz. Fused silica was selected as sensor material with consideration of chemical and electrical reaction of human body to the material. $2mm{\times}5mm{\times}0.5mm$ pressure sensors fitted to radial artery were fabricated on the substrates by consecutive microfabrication processes: sputtering, etching, photolithography, direct bonding and laser welding. Resonant frequencies of the fabricated sensors were in the range of 269~284 MHz under 760 mmHg pressure.

• Journal of the Korean Society for Precision Engineering
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• v.30 no.1
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• pp.18-23
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• 2013

Omni-directional robot is a typical holonomic constraint robot that has three degrees of freedom movement in 2D plane. In this study, a new omni-directional robot whose wheels are arranged in radial directions was proposed to improve driving performance of the robot. Unlike a general omni-directional robot whose wheels were arranged in a circumferential direction, moments do not arises in the proposed robot when the robot travels in a straight line. To analyze driving performance, dynamic modeling of the omni-directional robot, which considers friction and slip, was carried out. By friction measurement experiments, the relationship between dynamic friction coefficient and relative velocity was derived. Dynamic friction coefficient according to the angle difference between robot travel direction and wheel rotation direction was also obtained. By applying these results to the dynamic model, driving performance of the robot was calculated. As a result, the proposed robot was 1.5 times faster than the general robot.

• Nuclear Engineering and Technology
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• v.53 no.5
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• pp.1403-1415
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• 2021

The transient capability of a SP₃ based pin-wise core analysis code SPHINCS is developed and verified through the analyses of the C5G7-TD benchmark. Spatial discretization is done by the fine mesh finite difference method (FDM) within the framework of the coarse mesh finite difference (CMFD) formulation. Pin size fine meshes are used in the radial fine mesh kernels. The time derivatives of the odd moments in the time-dependent SP₃ equations are neglected. The pin homogenized group constants and Super Homogenization (SPH) factors generated from the 2D single assembly calculations at the unrodded and rodded conditions are used in the transient calculations via proper interpolation involving the approximate flux weighting method for the cases that involve control rod movement. The simplifications and approximations introduced in SPHINCS are assessed and verified by solving all the problems of C5G7-TD and then by comparing with the results of the direct whole core calculation code nTRACER. It is demonstrated that SPHINCS yields accurate solutions in the transient behaviors of core power and reactivity.

• Korean Journal of Applied Biomechanics
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• v.33 no.2
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• pp.52-61
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• 2023

Objective: This study aimed to investigate the effect of a combined functional intervention program on the pain-related questionnaire, the erector spinae contractile properties, and trunk extensor strength of prime-aged females with non-specific chronic low back pain. Method: 16 (female: 16) prime-aged subjects (age: 60.88 ± 6.09 years, height: 158.16 ± 5.58 cm, weight: 59.05 ± 9.44 kg) participated in this study. Results: Except for Tampa Scale of Kinesiophobia all pain-related questionnaires revealed a significant decrease after the intervention program (p<.001). Tensiomyography of the erector spinae revealed a significant post-intervention program increase in the maximum radial displacement (p<.05) and velocity of contraction (p<.05), however, there wasn't a significant post-intervention program change in the contraction time. Additionally, Trunk extensor strength showed a significant increase post-intervention program (p<.001). Conclusion: Our results indicated that the combined functional intervention program positively changed pain-related questionnaires and reduced erector spinae muscle stiffness, increasing the velocity of erector spinae contraction. Additionally, improved the trunk extensor strength.

• Journal of Korean Ophthalmic Optics Society
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• v.15 no.2
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• pp.151-154
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• 2010

Purpose: We investigated how the movement of iris and visual axis affects the finite schematic eye Methods: Using the schematic eye with the crystalline lens in the existing forms of the radial GRIN and the spherical GRIN, the iris centre was moved 0.5 mm in nasal direction and visual axis was tilted $5^{\circ}$ in same direction, with the additional degree of 2.5 down to locate the focal point in fovea. This study analyzed performance change of the optical system, designing it same as the real eye. Results: The whole aberration distribution showed a considerable difference in performance in comparison with the real eye; the biggest difference shown at the central field of optical system. The spherical aberration showed the biggest difference, and a peripheral power error and field curvature leaned toward (+) direction in aberration distribution. Conclusions: When designing the schematic eye with the performance similar with that of the real eye by taking into consideration the iris centre and visual axis, the aberration at the center field of optical system in particular should be corrected. Spherical aberration which showed the biggest difference should be corrected in the first place. In addition, a peripheral power error and field curvature that leaned toward (+) direction should be moved toward (-) direction.

• Journal of the Korean Wood Science and Technology
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• v.39 no.1
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• pp.15-20
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• 2011

The pine wilt disease is one of the most serious forest diseases that kill the pine trees, and the study on the invasion and movement of the pine wood nematode within the tree is very important for understanding the inhabitation of pine wood nematode. In this relation, the microscopic observation was carried out to study the place of inhabitation and movement of pine wood nematode within the infested wood. In result, the rays were mainly infested by pine wood nematode and showed dark discoloration due to their necrosis in cross, radial and tangential surface. Also, the intensive damage was found in the resin canals. On the other hand, some traumatic resin canals in tangential band were identified in the sapwood near the cambium. In the ray, the pine wood nematode occurred more commonly in the ray parenchyma cell and fusiform ray with horizontal resin canal than in the ray tracheid and uniseriate ray without horizontal resin canal, respectively. The pine wood nematode was thought to move from ray to tracheid through the large natural opening, window-like pit, in the cross-field, neither through the small natural opening, bordered pit, in the tracheid nor through the tracheid wall by creating a bore hole.

• Journal of the Korean Wood Science and Technology
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• v.48 no.4
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• pp.513-526
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• 2020

The existing preservation methods are difficult to be applied to a large dimension log which is needed for making traditional wooden ship 'Jalur' in Riau Province. Novel techniques to provide the use of readily available species to replace traditional species alternative were investigated. These included infusion and a combination of injection and bandage-wrapping methods for preserving living trees of Balam (Macaranga conifera (Rchb.f. & Zoll.) Müll.Arg.) and Bintangor (Calophyllum soulattri Burm.f.). Water-based boron compounds were applied as wood preservatives. In total, 18 discs from the bottom, middle, and top of four trees and two controls were used. Trees undergoing treatment were also used to see how wood anatomical structure might affect the boron penetration. The overall aim was to identify the best method for use in Jalur manufacturing. The results showed that in infused Balam tree where the hose position for the preservative intake was deep (10-15 cm from the bark), no boron compound was observed in the outer sapwood. Combination of injection and bandage-wrapping method gave higher percentage of boron penetration at bottom and middle of Balam tree. However, infused Bintangor showed 100% boron penetration. The larger vessel diameter, the absence of tyloses, and the simple perforation plates in Bintangor wood were likely to have contributed to the higher penetration of boron. The combination of bandage-wrapping and infusion, or alternatively by infusing the living trees close to the bark, and at as low as position in the stem gives better protection when treatments are applied to living trees.

• Journal of Acupuncture Research
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• v.20 no.6
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• pp.201-209
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• 2003

Objective : Recently, Seguele of Traffic Accident patients are increasing, especially cervical injury bring only severe sequela but also mortal damage to the patient. In treatment of the disease, the east medical treatment is another effective method. Methods : The patient resisted the west theraphy improved greatly in movement and sensation by acupuncture, moxibustion, herb medication and Physical treatment. In MRI, The treatment result is proved. Acupuncture on Stomach Meridian(足陽明胃經) referring to Naijing(內經) is thought effective. Results : Tetraplegia by Traffic Accident is considered as Wei Symptom in term of the east medicine, By means of radial and physical study of the patient treated by the east medicine, we are conviced that the east medicine is the excellent method Conclusions : Referring to the past documentary data, The only Treatment on this disease is Surgical operation, but the operation isn't the successful one because seg. of spinal cord injury is mortal. The east treatment, acupuncture, moxibustion herb medication and physical treatment isn't only effective but also satisfactory. In the future, The study on this disease by the east medicine should be made thoroughly.

• Journal of Power System Engineering
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• v.13 no.6
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• pp.95-101
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• 2009

The generator for gas turbine power generation consists of the rotor which generates magnetic field, the winding coil which is the path for the field current and the wedge and retaining ring which prevents the radial movement of the coil. Relatively severe deformation was observed at the coil end section during the inspection of the generator for peaking-load operation, and the thermal-electricity and the centrifugal force were evaluated by the simple modeling of the windings to find the cause. But the simulation stress was not sufficient to induce the coil plastic deformation. The analysis result seems to be applicable to the base-load generators which runs continuously without shut down up to a year, but there had been more deformation than simulated for the generator which is started up and shut down frequently. The cause of the coil deformation was the restriction of the expansion and shrinkage. The restriction occurs when the winding coil shrinks, and the stress overwhelms the yield stress and cause the plastic deformation. The deformation is accumulated during the start-ups and shut-downs and the thermal growth occurs. The factors which induce the coil restriction during the expansion and shrinkage should be reduced to prevent the unallowable deformation. The resolutions are cutting off the field current earlier during the generator shut-down, modifying the coil end section to remove the stress concentration and making the insulation plate inserted between the coil end section and the retaining ring have the constant thickness.

• Physical Therapy Korea
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• v.11 no.4
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• pp.7-17
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• 2004

Individuals who propel wheelchairs have a high prevalence of upper extremity injuries (i.e., carpal tunnel syndrome, elbow/shoulder tendonitis, impingement syndrome). Musculoskeletal injuries can result from overuse or incorrect use of manual wheelchairs, and can hinder rehabilitation efforts. To better understand the mechanisms of upper extremity injuries, this study investigates the motion of the wrist during wheelchair propulsion. This study also examines changes in the variables that occur with fatiguing wheelchair propulsion to determine how the time parameters of wheelchair propulsion and the state of fatigue influence the risk of injury. A two dimensional (2-D) analysis of wrist movement during the wheelchair stroke was performed. Twenty subjects propelled a wheelchair handrim on a motor-driven treadmill at two different velocities (50, 70 m/min). The results of this study were as follows; The difference in time parameters of wheelchair propulsion (cadence, cycle time, push time, recovery time, and PSP ratio) at two different velocities was statistically significant. The wrist kinematic characteristics had statistically significant differences at two different velocities, but wrist radial deviation and elbow flexion/extension had no statistically significant differences. There were statistically significant differences in relation to fatigue in the time parameter of wheelchair propulsion (70 m/min) between initial 1 minute and final 1 minute. The wrist kinematic characteristics between the initial 1 minute and final 1 minute in relation to fatigue had statistically significant differences but the wrist flexion-extension (50 m/min) had no statistically significant differences. According to the results, the risk of musculoskeletal injuries is increased by fatigue from wheelchair propulsion. To prevent musculoskeletal injuries, wheelchair users should train in a muscle endurance program and consider wearing a splinting/grove. Moreover, wheelchair users need education on propulsion posture, suitable joint position, and proper recovery patterns of propulsion.