In this paper, carbon/glass intra-hybrid woven fabric as reinforcement and vinyl ester resin as matrix, CF/GF composite was manufactured through hand lay-up method. Then, the investigation on the mechanical property and initial fracture behavior was carried out. Initial fracture stress or knee point stress was the main factor of initial damage which discussed with AE characteristics during mechanical test. Scanning electron microscope observation was also carried out to observe the fracture of materials after testing. Besides, model of the woven fabric was built by finite element analysis method (FEM) and then the fracture mechanism was simulated by the software Marc. By combining the experimental results and finite element analysis, stress-strain curve and initial behavior of fracture progress in resin hybrid composite materials were predicted.

ABSTRACT. Concern has been growing about the cardiac toxicity of antimalarial drugs. Artemisinin, a unique type of antimalarial drug originating from a Chinese medicinal plant, has minimal adverse effects, but it has been reported to inhibit delayed rectifier potassium current, a voltage-gated potassium current. However, no studies have been published concerning the effect of artemisinin on ligand-gated potassium currents. Therefore, in the present study, we examined the influence of artemisinin on the acetylcholine receptor-operated potassium current (I K.ACh ), a ligand-gated potassium current, in guinea pig atrial myocytes using a patch clamp technique. Artemisinin(1 to 300 µM) inhibited I K.ACh induced by extracellular application of both carbachol (1 µM) and adenosine (10 µM) and that induced by intracellular loading of GTPγS (100 µM) in a concentration-dependent manner. Artemisinin inhibited carbachol-induced, adenosineinduced, and GTPγS-activated I K.ACh within almost the same concentration range. In left atria, artemisinin (1 to 100 µM) partially reversed the shortening of action potential duration induced by carbachol in a concentration-dependent manner. Carbachol-induced negative inotropic action in left atria was also inhibited by artemisinin (10 to 300 µM). In conclusion, we suggest that the anticholinergic action of artemisinin is mediated through inhibition of I K.ACh via inhibition of the muscarinic potassium channel and/or associated GTPbinding proteins. KEY WORDS: acetylcholine receptor-operated potassium current, anticholinergic effect, artemisinin, guinea pig, heart muscle.

Mechanical joints are usually and easily used for joining structural parts. However, for joining composite parts, stress concentration at the edge of circular hole of composite laminates leads local and ultimate destruction of the entire structure. Therefore, needle punching techniques were focused on to improve composite strength around open holes. Needle punch process can make handling abilities of textile fabrics by special needles for entangling fibers. By applying this technique, interlaminar properties of the composite laminates can be improved, therefore restrain of crack propagation at open holes by needle punch technique can be expected. However, effect of needle punch process on tensile properties have not been investigated. In this study, effect of needle punch process for glass fiber chopped strand mat as a reinforcement of composite materials on tensile properties of the composites with an open hole was investigated by changing needle punch density. The tensile strength was increased and decreased with increase in needle punch density. From the crosssectional observation, dispersion of fibers by kneedle punch process was the reason to improve mechanical properties.

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In recent years, due to its high specific stiffness and strength, fiber reinforced plastics (FRP) are being used in aerospace components, automobile components, sports equipment, and in various other applications. Especially since composite laminates have superior mechanical properties, there is a high demand for their use as structural materials. However, mechanical properties in the out-of-plane direction of composite laminates, specifically the interlaminar strength and fracture toughness, are much weaker than those in the inplane direction. This study focuses on the needle punch techniques that aim to improve composite properties in the out-of-plane direction. This technique is typically used for fabricating non-woven fabrics. Fiber webs were punched by a plate containing many special needles with many barbs. A portion of fibers in the in-plane direction were aligned in the out-of-plane direction. In this study, the needle punch process is applied on chopped strand mats. Static tensile tests, fatigue loading tests, and residual strength tests are performed. Tensile properties, residual strength properties and fracture mechanisms of FRPs with needle-punched chopped strand mats are investigated.