Strong and Tough Glass with Self-Dispersed Nanoparticles via Solidification.

Glassy materials can be broadly defined as any amorphous solid, which are important in nature and have significant societal value for their applications in daily life and industry. Although many methods have been applied, the fracture toughness of traditional glasses is still very low due to intrinsic brittleness, significantly limiting their use for structural applications. While nanoelements may be added into glasses and ceramics to form nanocomposites with enhanced properties, it is extremely difficult to distribute and disperse them inside the liquid glass/ceramic matrix with traditional processing methods. It is shown that a strong and tough glass can be fabricated through a direct-solidification process using a nanoparticle self-dispersion mechanism in a glass melt (2MgO·2Al2 O3 ·5SiO2 ) with the assistance of B2 O3 , delivering a 6.1% strain limit and strength up to E/14 (E is elastic modulus), which is close to the theoretical limit of E/10 and one of the highest among all materials reported so far. The fracture toughness of the glass with 30 vol% SiC nanoparticles is significantly higher than any other inorganic glass tested under similar conditions. This new method opens up remarkable opportunities for glass and ceramic research, manufacturing, and applications.

Three-Dimensional Printed Piezoelectric Array for Improving Acoustic Field and Spatial Resolution in Medical Ultrasonic Imaging.

Piezoelectric arrays are widely used in non-destructive detecting, medical imaging and therapy. However, limited by traditional manufacturing methods, the array's element is usually designed in simple geometry such as a cube or rectangle, restricting potential applications of the array. This work demonstrates an annular piezoelectric array consisting of different concentric elements printed by Mask-Image-Projection-based Stereolithography (MIP-SL) technology. The printed array displays stable piezoelectric and dielectric properties. Compared to a traditional single element transducer, the ultrasonic transducer with printed array successfully modifies the acoustic beam and significantly improves spatial resolution.

Morphologic studies of high fall injuries.

OBJECTIVE: By studying the mode and morphologic character of high fall injuries on the scene, and exploring the injury situation of different heights, different fall ways and postures, to provide a reference for the forensic identification of high fall injury. METHODS: All the high fall cases were statistically analysed according to their gender, age, ground-touching posture, fall height, site and type of the injury. RESULTS: Among 134 high fall cases, 98 were male and 36 were female with the age ranging from 2-71 years (37.6+/-16.9 on average), in which, 10-60 years old group consisted of 110 cases (82%). Most cases fell from windows or roofs (73%) and the touching objects were cement ground or shaft bottom of elevators. Among these cases, head injury was generally serious, followed by chest and abdominal injuries. The morphologic changes depend upon the height, nature, as well as the posture at the point while the body touches the ground. CONCLUSION: Morphologic study of high fall injury assists medicolegal physicians to make correct identifications of the cause and nature of high fall injuries.