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[en] We developed a new method for immobilization of the fix lower extremities by using a thermoplastic mask, a carbon fiber base plate, a customized headrest, and an adjustable angle holder. The lower extremities of 11 patients with lower extremity tumors were immobilized by this method. CT simulation was performed for each patient. For all 11 patients, the device fit was suitable and comfortable and had good reproducibility, which was proven in daily radiotherapy
[en] Properties of carbon fibre of relevance to its use for megavoltage radiotherapy applications have been investigated. Measurements have been made of the percentage transmission and percentage build-up of carbon fibre at energies of 5, 6 and 8 MV. The results are presented in comparison with those obtained for other materials commonly used in radiotherapy: polymethylmethacrylate (PMMA), PETG copolyester and expanded polystyrene foam. It was found that carbon fibre has a higher percentage transmission and a lower percentage build-up than either PMMA or PETG copolyester. It was also found that the build-up due to a combination of carbon fibre and 5 cm of polystyrene foam was less than 65% over the energy range for which measurements were made, and much lower than that due to PETG copolyester. It is thus proposed that carbon fibre is a suitable material from which to make devices for use in megavoltage radiotherapy. (author)
[en] The optimum ultrasonic test conditions for the thin carbon fiber reinforced plastic (CFRP) sheet were determined for the immersed reflector plate method. The effects of the water distance, the surface conditions of the specimen and transducer characteristics were studied. For a reliable test the water distance between the transducer and the front surface of the specimen should be determined when the beam profile of the transducer appears in the bell-shape. The detectability of the defect was improved as the effective beam width of the ultrasonic transducer became narrow. The transducer should be properly chosen considering to the surface condition of the test material as well as the size and type of the defect to be detected. It was possible to detect the flat bottom hole whose diameter is as small as about 500 micrometer
[en] Functionally graded composite (FGC) materials are categorized as advanced materials that display different thermal and mechanical responses compared with well-known composites, such as carbon fiber or glass fiber-reinforced composites. This paper presents the experimental results for the drilling of three materials, namely glass/epoxy, carbon/epoxy, and FGC material. FGC was compared with carbon and glass/epoxy composites in terms of thrust force, delamination factor, diameter of hole, and roundness during drilling. This study illustrated that the drilling performance of FGC is considerably more complicated than that of more common composite materials, such as glass/epoxy and carbon/epoxy. Delamination factor at the exit of hole during drilling of FGC was mainly affected by the material placed at the exit of the hole. The proposed cutting parameters and drill geometries to minimize the occurrence of delamination during drilling of carbon/epoxy and glass/epoxy apparently does not meet the expectation in drilling FGC.
[en] Highlights: • The presentation of a self-powered e-skin with combination of PDMS and carbon fiber. • It provides a simple route to achieve high-resolution pressure sensing by using micro-size conductive fibers. • With excellent flexibility, the device can be adhered on most curved surfaces for pressure sensing purposes. • The unique construction of the e-skin brings about a significant reduction in the number of test channels. Electronic skin (e-skin) comprises a network of tactile sensors, which has broad application prospects in prosthetics, advanced robotics and continuous health monitoring. Here, a self-powered artificial e-skin is fabricated in a simple and cost-effective method for high resolution pressure sensing. No external power supply is needed for the e-skin owing to the triboelectric mechanism. The response time of pressure sensing is approximately 68 ms and the sensitivity is 0.055 nA K Pa−1. With excellent flexibility, the device can be adhered on most curved surfaces for pressure sensing purposes. The fabricated e-skin with resolution as high as 127×127 dpi is capable of mapping the 2D tactile trajectory of a tip. The resolution can proceed to be improved with the enhancement of the pixel density. Furthermore, the unique construction brings about a significant reduction in the number of the test channels from N×N to 2×N, which greatly decreases the measurement costs. This work offers an effective step for e-skin, with superiorities of self-powered, high resolution, simple fabrication and low-cost.
[en] The dispersibility of non-damaged carbon fibers and the stability of fiber position have a crucial influence on the properties of continuous carbon fiber reinforced aluminum matrix (Cf/Al) composites. In order to avoid the damage to the fiber caused by excessive infiltration pressure, which can be controlled by adjusting the distance from the vibration head to the fiber bundle. The effect of different binding force on the distribution and the fixed position of non-damaged carbon fibers in the matrix were studied. The results show that with the fiber binding force increases (0 N, 2 N and 4 N), the carbon fiber bundles can be stably located in a predetermined position and gradually completely infiltrated, but with the binding force further increases (6 N and 8 N), the fiber clusters and uninfiltrated defects appeared again. It is found that the proper fiber binding force can ensure that the carbon fiber does not shift under the infiltration pressure, so that the fibers distribute uniformly in the composite, but the excessive binding forces can obviously inhibit the dispersion of the fibers. Tensile test results show that the ultimate tensile strength increases first and then decreases with the increasing of fiber binding force. When binding force reach to 4 N, the tensile performance of the composites is 203 MPa at its best. The uniform distribution of carbon fibers in the matrix play an important role in improving the tensile performance of Cf/Al composites. (paper)
[en] Carbon nanotube (CNT) fiber made from millions of carbon nanotubes (CNTs) that are highly-aligned in the axial direction, is lightweight and has many desirable properties, such as high strength and high ductility. CNT yarn is fabricated by twisting several CNT fibers to obtain improved electromechanical properties. In this paper, the mechanical behavior and electrical response of CNT fiber and their multi-ply yarns under uniaxial single and cyclic loads were investigated experimentally. The results reveal that the gauge factor of the CNT fiber is about 1.65. For CNT yarn, the sensitivity of the resistance variation decreases slightly with the number of fibers twisted in CNT yarn increasing, while the stability of resistance variation improves. The cyclic test result shows that the relative resistance changes linearly with strain. In addition, preload treatment will improve the stability of electromechanical property for CNT yarn sensors. (paper)