The combination of hydroxyapatite composite powder and three-dimensional (3D) printing rapid prototyping techniques has markedly improved skeletal interactions in orthopedic surgery applications. 3D printing methodology ensures effective bionic microstructure and shape interactions between an implant and the surrounding normal tissue. In effort to enhance the quality, precision, and mechanical properties of printed bone scaffolds, this study examines binder droplet spreading performance on the surface of hydroxyapatite (HA) microspheres. The piezoelectric nozzle diameter is about 10 μm, which sprays droplets 20 μm in diameter. The average size of HA powder particles is about 60 μm in diameter. Most laboratories, however, are limited to observation of a single droplet 20 μm or smaller in diameter impacting a spherical surface 60 μm in diameter. Based on non-dimensional scale similarity theory in axisymmetric Stokes flow dynamics, this study conducted experiments and simulation on the same collision conditions (droplet 200 μm in diameter, spherical surface 600 μm in diameter). Simulation results were consistent with experiment data, and form a basis for future research on modeling droplet impact on spherical surfaces.

Before performing bone surgery, a diagnosis is obtained mainly based on CT digital images. It is impossible for surgeons to test their operation plans and recovery strategy before surgery. Choosing between strength-match bone nails and bone plates is difficult, and post-operative stress complication is inevitable. Surgeons need to measure defect areas carefully in order to choose appropriate internal fixation devices based only on experience. Consequently, surgery time increases. Longer surgery time means a higher possibility for vein thrombosis or even artery thrombosis. In addition, for caput femoris, which contains many vessels and nerves, a long surgery is more likely to cause intraoperative complications, disability, or even death. A 3DP customized bone preoperative diagnosis model can characterize a given fracture or defect precisely, and thus increase the observation field of view before surgery. This paper first analyze the model structure of skeletal anatomy, and then study the skeletal bionics design of the internal micro structure, the preoperative diagnosis outline shape structure, and the biomechanical property. Based on this study, we fabricate different strength bone scaffold by controlling the 3DP processing parameters, materials size and their shape. The preoperative diagnosis model can help surgeons define the level and type of bone defects. It facilitates choosing between bone nails and bone plates. The preoperative model can also be used as basis to set up bone nails, bone plates, and bone substitute implanting plans. As a physical model for preoperative design, recovery simulation, implant choice, and 3D spatial data measurements, the 3DP preoperative diagnosis model can substantially improve the effect of surgery, decrease surgery time, and consequently, decrease the possibility of intraoperative and post-operative complications.

设计并制备了一种带有电流导引结构的新型倒装AlGaInP LED.实验结果表明,在20 mA直流电流注入下,器件的电压为2.19V,输出光功率与普通倒装器件相比提高了17.33％.通过电流导引结构,使得器件注入电流被主动引导到电极以外部分,有效增大了上电极以外部分有源区中用于发光的有效载流子数目的比例,同时减轻了电流密度过大现象,大大提高了器件的出光效率.

A novel two-wafer concept for micro-electro-mechanically tunable vertical cavity surface emitting lasers (VCSELs) is presented. The VCSEL is composed by two wafers: one micro-electromechanical-system membrane wafer with four arms to adjust the cavity length through electrostatic actuation and a "half-VCSEL" wafer consisting of a fixed bottom mirror and an amplifying active region. The measurement results of the electricity pumped tunable VCSEL with more than 9 mW output power at room temperature over the tuning range prove the feasibility of the proposition.

Thermal characteristics of AlGaInP thin-film LED with transparent conducting ITO p-type contact by electrical method are presented and discussed . Samples without ITO fabricated from the same AlGaInP /GaAs epitaxial material are also prepared as references . The temperature coefficients of the samples are measured firstly and they are used as temperature sensitive parameters to determine the temperature rise . Heating response curves show that the temperature of chip in the sample with ITO is about 9K lower than the sample without ITO when the time of applying 60mA operation current exceeds 10 5 μs. It can be also calculated that thermal resistance(from chip to ambient condition) of the sample with ITO is about 40K/W lower than the one without ITO. Finally we make the conclusion that the ITO layer is helpful for the thermal management of LED and it can improve the reliability the AlGaInP thin-film LED effectively.