• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.1613-1616
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• 1997

In order to develop a human hand mechanism, a 5-bar finger with redundant actuation is designed and implemented. an optimal set of acutator locations and link lengths for the case of one redundant actuator is obtained by employing a composite design index which simulataneously consider several performance indices such as workspace, isotropic index, and force transmission ratio. Each joing is driven by an compact actuator mechanism having ultrasonic motor and a gear set with poeneiometer an controlled by VME Bus-based control system.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.48-51
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• 1996

A 5-bar structure with redundant actuators is proposed as a finger mechanism. It is shown that one additional redundant actuator greatly enhances the load handling capacity of the system. The actuator location should be carefully decided to maximize the performance enhancement. Furthermore, we develop stiffness and frequency control algorithms based on the internal loading created by redundant actuation. The effectiveness of these algorithms have been demonstrated by simulations.

• 한국태양에너지학회:학술대회논문집
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• 2011.04a
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• pp.116-120
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• 2011

In this paper, we studied the optimization of the screen pringting method for crystalline silicon solar cell fabrication. The 156 * 156 mm2 p-type silicon wafers with $200{\mu}m$ thickness and $0.5-3{\Omega}cm$ resistivity were used after texturing, doping, and passivation. Screen printing method is a common way to make the c-Si solar cell with low-cost and high-efficiency. We studied the optimized condition for screen printing with crystalline silicon solar cell as changing the printing direction (finger line or bus bar), finger width, and mesh angle. As a result, the screen printing with finger line direction showed higher finger height and better conversion efficiency, compared with one with bus bar direction. The experiments with various finger widths and mesh angles were also carried out. The characteristics of solar cells was obtained by measuring light current-voltage, optical microscope and electroluminescence.

• Annals of Clinical Neurophysiology
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• v.2 no.1
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• pp.21-26
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• 2000

Background: There has been few electrophysiologic studies in median proper palmar digital nerve(PPDN). Bar electrode may be a useful tool to evaluate the pathophysiologic state of the distal peripheral nerves. Objectives : To evaluate sensory nerve conduction velocities(NCVs) of median PPDNs in normal controls and carpal tunnel syndrome(CTS) patients by bar electrode, and clarify the usefulness of the bar electrode. Methods : We checked NCV of each median PPDN of thumb(D1), index(D2) and middle finger(D3) in normal controls(68 hands) and CTS patients(95 hands) by bar electrode. The each mean NCV of both groups were compared to find the correlation between them. Results : The mean NCV of each median PPDN in control group were $38.7{\pm}4.2$(D1), $32.0{\pm}4.6$(D2), $34.2{\pm}4.4$(D3) m/sec, and in CTS group were $35.3{\pm}8.9$(D1), $20.2{\pm}5.2$(D2), $20.2{\pm}5.1$(D3) m/sec orderly. There were significant differences between mean NCV of each finger in control group(p=0.0001), but not between each left and right finger(p>0.05). The differences between each mean NCV of control and CTS were significant in all 3 fingers(p=0.0014, 0.0000, 0.0000). Conclusion : Bar electrode is a useful tool to evaluate the pathophysiologic state of the median PPDNs in normal controls and CTS patients.

• Membrane and Water Treatment
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• v.15 no.2
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• pp.79-88
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• 2024

Modification of Polyvinylidene fluoride (PVDF) hollow fiber membranes (HFMs) characteristics and performance were investigated via post treatment using different oxidants. sodium hypochlorite (NaOCl), hydrogen peroxide (H₂O₂) and potassium persulfate (KPS). Fourier transform infrared (FTIR) and Proton nuclear magnetic resonance (¹H-NMR) results revealed no structural differences after post treatment. Cross-sectional micrographs show finger-like structures at the outer and inner walls of the HFMs and sponge-like structures in middle, where NaOCl and KPS post treated fibers exhibited a decrease in finger-like structures in addition to aggregates appearing on the surface, consequently leading to an increase in the surface roughness (Ra) from 48 nm to 52.8nm and 56 nm, respectively. Hydrogen peroxide post treatment only was observed to decrease the water contact angle from 98° to 81.4°. It was also observed that the elongation at break and the modulus deceased after NaOCl post treatment from 34.5 to 28.5% and from 19.3 Mpa to 16.6 Mpa, respectively. Moreover, pure water flux after H₂O₂ post treatment increased from 87.8 LMH/bar to 113 LMH/bar at 0.45 bar, while no changes were detected for the methylene blue dye rejection (74%) between raw and hydrogen peroxide post treated fibers at the same pressure. According to the findings hydrogen peroxide post treated PVDF HFMs have the most uniform surfaces, with almost no alterations in structural and mechanical properties or porosities with enhanced hydrophilicity and pure water flux maintaining appropriate rejection. Therefore, it is considered an efficient surface modifying agent for UF/NF membranes or low-pressure separators.

• Archives of Craniofacial Surgery
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• v.21 no.6
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• pp.384-386
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• 2020

This report describes osteotomy and iliac bone graft for malunion caused by failed mandibular fracture reduction. A 27-year-old man was referred 3 months after a motor vehicle accident. At another hospital, two operations had been performed for symphyseal fracture using two resorbable plates. Malocclusion was noted, and panoramic radiography and computed tomography revealed a misaligned dental arch, with a 9.37-mm gap between the central and the lateral incisor of the left mandible. A wafer was made from the patient's dental model, and a maxillary arch bar was applied. Through a lower gingivolabial incision, osteotomy was performed between the malunited symphyseal fracture segments. Both segments were reduced to their original position using the wafer and fixed with titanium miniplates via intermaxillary fixation (IMF). The intersegmental gap was filled with cancellous bone from the iliac crest. The gingival defect was covered with a mucosal transposition flap from the gingivolabial sulcus. IMF and the wafer were maintained for 5 and 9 weeks, respectively. At postoperative week 13, the screws were removed from the mandible and satisfactory occlusion was noted. His mouth opening improved from 2.5 to 3 finger breadths (40 mm). This case demonstrates the need for sufficient IMF when using resorbable plates.