• Journal of Chest Surgery
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• v.29 no.9
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• pp.1045-1049
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• 1996

Post-intubation tracheoesophageal fistula is rare, and its management causes a serious problems to surgeons. We have experienced 4 cases in 3 patients. Simple ditcision and closure of the fistulas were done by trans-cervical approach after weaning of ventilator. The tracheal defect was closed by simple suture, and the esophageal defect was closed in two layers before a viable muscle flap was interposed between the two suture lines in order to prevent recurrence. There was one delayed tracheal stenosls and one recurrent fistula, and these complications were also managed success ully.

• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.1704-1707
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• 1997

In this work, position and vibratiion control of a two-link manipulator with one flexible link, which an unkoun but bounded payload mass and two pair of artificial muscle-type penumatic actuators, are investgated. A flexible link robot has advantages over a figid link robot in the sense that it is much safer when it cones into contact with its environment, including humans. Furthermore, for the sake of safety, it would be more desirabel if an actuator could deliver required force while maintaining proper compliance. An artificial muscle-type penumatic actuator is adequate for such cases. In this study, a controller based on singular perturbation method, adaptive and sliding mode contro, and .mu.-synthesis is developed. The effectiveness of the proposed control scheme is confirmed through simulations and experiments.

• 기계와재료
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• v.23 no.2
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• pp.54-65
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• 2011

전기 활성 고분자 복합재는 전기적 자극을 가하여 기계적 움직임을 얻을 수 있고, 기계적 자극을 통해 전기적 신호를 얻을 수 있어 차세대 액추에이터 및 센서와 생물학적 조직과의 유사성으로 인공 근육 및 로봇분야의 응용소재로 최근 주목받고 있다. 본고에서는 전기 활성 고분자 복합재의 기본적이 개념과 함께 국내외 기술 동향을 살펴보았다. 또한 전기 활성 고분자 복합재에 있어 핵심내용인 전기활성 소재의 종류 및 작동원리, 전극소재, 이를 이용한 센싱 및 액추에이팅 구동특성과 응용에 대해 소개하고 마지막으로 현 시점에서의 전기 활성 고분자 복합재 응용에 있어 문제점과 이를 해결하기 위한 연구방안에 대해 언급한다.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.22 no.2
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• pp.331-336
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• 2013

The purpose of this study is to visualize the characteristics of ER fluids as preceding step of developing 3 port ER valves. As the strength of the electric field increases, more clusters in flow are made and these clusters are thought to be the reasons of the load flow rate being increased and the outlet flow rate being decreased. The ER Valves and load and outlet flow rate check method are considered to be applied to the fluid power control system. Using the manufactured pressure control valve, a one-link manipulator with FHA in robot system is driven. As a result, it is experimentally confirmed that the pressure control valve using ER fluids is applicable to use in driving actuator. If it applies characteristics of the ER fluids, it will be able to apply in the control system for the ER Valve which occurs from industrial controller(PLC).

• The Journal of Korea Robotics Society
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• v.16 no.1
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• pp.17-22
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• 2021

Soft robot research has been actively conducted due to the advantages of soft materials that have less motion restrictions and higher energy efficiency compared to rigid robots. In particular, soft robots are being applied in more and more diverse fields, and the need for soft robots is increasing, especially when dealing with soft or deformable objects that rigid robots cannot perform. Various soft robots are being developed, and studies on artificial muscles with versatility, seamless integration with sensing, and self-healing capabilities are being proposed. In this study, we propose one of the most simple rectangular shaped HASEL (Hydraulically amplified self-healing electrostatic) actuators and compare the performance according to shape deformation such as the size or ratio of actuators and electrodes. Developing these actuators can be used in many ways for artificial muscles in soft robotics.

• The Journal of Korean Academy of Prosthodontics
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• v.54 no.4
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• pp.407-412
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• 2016

The neutral zone technique is an alternative approach for the construction of complete dentures on highly atrophic ridges with history of denture instability. This technique achieves two objectives. First, the teeth will not interfere with the normal muscle function, and second, the force exerted by the musculature against the denture is more favorable for stability and retention. In this case of a 78-years-old female patient with severely atrophic ridges who had been using unstable complete dentures, the neutral zone impression technique was used to increase the stability and the retention of dentures. The neutral zone for both arch was located with modeling compound. After the arrangement of artificial teeth within the neutral zone, the external impression was taken to determine the tissue surface. The final dentures showed enhanced stability and retention and the patient was satisfied with the new dentures with respect to functional and esthetic aspects.

• Polymer(Korea)
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• v.30 no.6
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• pp.471-477
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• 2006

Ion exchange metal composite(IPMC) has toughness equivalent to the range of human's muscle, transformation-actuation force by relatively low voltage and the fast response time. Thus, as a new method for preparing thicker IPMC, the solution casting method to make the films of various thicknesses out of liquid nation was attempted in this study. To reduce the surface resistance of electrode, the first plated electrode prepared by Oguro method was replated with Au and Ir using ion beam assisted deposition(IBAD). The microstructures of electrode surfaces before and after IBAD plating were investigated using SEM. The change of water and ion-conductivity in IPMC were measured under applied voltage. The displacement and driving force of IPMCs with various thicknesses were measured to evaluate the driving properties.

• Journal of Korean Academy of Nursing
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• v.38 no.6
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• pp.874-880
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• 2008

Purpose: The purpose of this study was to identify muscle atrophy in critically ill patients on ventilators. A comparison was made between limb circumferences and muscle areas on the day of admission to an intensive care unit (ICU) and on the 8th day after admission. Methods: The data were collected from 30 critically ill patients using ventilators at S hospital ICU in Seoul during the period from October 2005 to April 2006. Limb circumferences and skinfold thickness were measured on the day of admission and on the 8th day after admission to the ICU. Limb circumferences and skinfold thickness were measured on the right mid-arm, right mid-thigh, and right mid-calf using a measuring tape and a skinfold calipers. Limb muscle areas were calculated by an equation after measuring limb circumferences and skinfold thickness. The data were analyzed by paired t-test and independent t-test. Results: 1) Mid-arm circumference, mid-thigh circumference and mid-calf circumference on the 8th day after admission to the ICU were significantly less than those on the day of admission to the ICU, 2) Mid-arm muscle area, mid-thigh muscle area and mid-calf muscle area on the 8th day after admission to the ICU were significantly less than those on the day of admission to the ICU, 3) Steroid and vecuronium medication didn't affect changes in limb circumferences (mid-arm, mid-thigh, mid-calf) and muscle areas (mid-arm, mid-thigh, mid-calf on the 8th day after admission to the ICU compared to the day of admission. Conclusion: Limb muscle atrophy may occur on the 8th day after admission to the ICU in critically ill patients using ventilator.

• Journal of the Korean Society for Precision Engineering
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• v.27 no.6
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• pp.82-89
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• 2010

Ankle-foot orthosis with an artificial pneumatic muscle which is intended for the assistance of plantarfelxion torque was developed. In this study, power pattern of the device in the various pneumatics and the effectiveness of the system were investigated. The pneumatic power was provided by ankle-foot orthosis controlled by user‘s physiological signal, that is, muscular stiffness in soleus muscle. This pneumatic power can assist plantarflexion torque of ankle joint. The subjects performed maximal voluntary isokinetic plantarflexion motion on a biodexdynamometer in different pneumatics, and they completed three conditions: 1) without wearing the orthosis, 2) wearing the orthosis with artificial muscles turned off, 3) wearing the orthosis activated under muscular stiffness control. Through these experiments, we confirmed the effectiveness of the orthosis and muscular stiffness control using the analyzing isokinetic plantarflexion torque. The experimental results showed that isokinetic torques of plantarflexion motion of the ankle joints gradually increased in incremental pneumatic. The effectiveness of the orthosis was -7.26% and the effectiveness of the muscular stiffness control was 17.83% in normalized isokinetic plantarflexion torque. Subjects generated the less isokinetic torques of the ankle joints in wearing the orthosis with artificial muscles turned off, but isokinetic torques were appropriately reinforced in condition of wearing the orthosis activated under muscular stiffness control(17.83%) compared to wearing the orthosis(-7.26%). Therefore, we respect that developed powered orthosis is applied in the elderly that has weak muscular power as the rehabilitation equipment.

• Journal of radiological science and technology
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• v.40 no.4
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• pp.567-573
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• 2017

The purpose of this study was to evaluate whether or not there was artifact when the upper limb could not be lifted to the top of the head during multi-detector computed tomography(MDCT) scans of the chest and abdomen. Contrast radiography of the human and chest phantom was performed with 128channal MDCT. Under the same conditions(120 kVp, 110 mAs, standard algorithm)both hands lifted up and put down each time in the human experiment. In the chest phantom experiment, the radiography was carried out when the upper limb phantom was adjusted at a certain distance(0, 3, 7 cm) from the chest phantom. Subsequently, the values of Noise, CT number, SNR, and CNR were measured in the field of concern. The noise value of fat, rib, and muscle increased when the arm was lifted in humans(0.79, 47.8, 27%). Furthermore, when the upper limb was lowered, the noise value of muscle and lung increased in the phantom(31.2, 9.4%). In addition, the noise value of the muscles and lung decreased by 5, 25.12% and 5.6, 15.35% as the upper limb moved about 0,3,7cm away from the chest. When the chest and abdominal radiography were performed, in the case of the presence of other parts outside the inspection area, the probability of artifact was minimal while the distance was more than 3cm away from the upper limb to the chest and abdomen.