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Amorphous and nanocrystalline Zinc Oxynitride (nc-ZnON) has been found to be one kind of potential materials for thin film transistors in the application of advanced display because of their high carrier mobility and low persistent photocurrent. We report a systematic study of ZnON properties and their correlation to the deposition conditions in a reactive sputtering process using a metallic Zn target in a gas mixture of Ar, N2 and O2. The most sensitive parameter to the material properties is O2 and N2 flow rates. At given N2 and Ar flow rates, the ZnON materials show polycrystalline ZnO properties when a relatively high O2 flow rate is used; become a mixture of ZnO and Zn3N2 with a nanocrystalline structure when a medium O2 flow rate is used; and finally show polycrystalline Zn3N2 properties when a small or no O2 flow rate is used. The RF power also shows a strong influence on the material properties. At a given gas mixture, a low RF power produces polycrystalline ZnO-like materials and a high power produces polycrystalline Zn3N2-like materials. At an optimized medium RF power, the material shows nc-ZnON properties. Finally, under the optimized condition, the nc-ZnON films are made with an optical bandgap of 1.3-1.5 eV, electron mobility above 80 cm2/V.s and electron density of 1x1018 cm-3, which are suitable for high quality TFTs in advanced display application.

It has been demonstrated that reprogramming factors are sequestered in the pronuclei of zygotes after fertilization, because zygotes enucleated at the M phase instead of interphase of the first mitosis can support the development of cloned embryos. However, the contribution of the parental pronucleus derived from either the sperm or the oocyte in reprogramming remains elusive. Here, we demonstrate that the parental pronuclei have asymmetric reprogramming capacities and that the reprogramming factors reside predominantly in the male pronucleus. As a result, only female pronucleus-depleted (FPD) mouse zygotes can reprogram somatic cells to a pluripotent state and support the full-term development of cloned embryos; male pronucleus-depleted (MPD) zygotes fail to support somatic cell reprogramming. We further demonstrate that fusion of an additional male pronucleus into a zygote greatly enhances reprogramming efficiency. Our data provide a clue to further identify critical reprogramming factors in the male pronucleus.

According to previous studies, the bond strength between the carbon fiber–reinforced plastics and metals mainly depends on the bond layer between the carbon fiber–reinforced plastic composites and the metal. This article presents the results of the experiments conducted on the tensile bond strength between the carbon fiber–reinforced plastic tubes and aluminum joints. The parameters examined in these experiments include adhesive type, surface roughness of the bonded area, and thickness and length of the bond layer. The results show that the 3M DP-460NS Off-White adhesive was suitable for our experiment. The bonded surfaces of the specimens were smoothened with a P600 sandpaper to achieve higher bond strengths with the adhesive. For the six bond thicknesses tested, a thickness of 0.2 mm was optimal for the tensile experiments. The ultimate tensile force was approximately directly proportional to the bond length.

The contact mechanics for a rigid wheel and deformable terrain are complicated owing to the rigid flexible coupling characteristics. Bekker’s equations are used as the basis to establish the equations of the sinking rolling wheel, to vertical load pressure relationship. Since vehicle movement on the Moon is a complex and on-going problem, the researcher is poised to simplify this problem of vertical loading of the wheel. In this paper, the quarter kinetic models of a manned lunar rover, which are both based on the rigid road and deformable lunar terrain, are used as the simulation models. With these kinetic models, the vibration simulations were conducted. The simulation results indicate that the quarter kinetic model based on the deformable lunar terrain accurately reflects the deformable terrain’s influence on the vibration characteristics of a manned lunar rover. Additionally, with the quarter kinetic model of the deformable terrain, the vibration simulations of a manned lunar rover were conducted, which include a parametric analysis of the wheel parameters, vehicle speed, and suspension parameters. The results show that a manned lunar rover requires a lower damping value and stiffness to achieve better vibration performance.

A high-thrust screw-type piezoelectric ultrasonic motor with a three-wavelength exciting mode is proposed in this paper. The motor mainly includes a stator and a screw output shaft, and the stator is composed of twelve rectangular piezoelectric plates and a hollow metal elastomer with an internal thread. The stator can be excited to generate the combined micro ultrasonic vibration mode. With this ultrasonic vibration mode, a three-wavelength traveling wave can be synthesized. The three-wavelength traveling wave is used to drive the screw output shaft by means of the frictional force between the stator and the shaft. Rotary-linear motion can be achieved without any additional conversion mechanism. Large thrust output can be easily obtained using a three-wavelength exciting mode. The exciting mode is analyzed in detail. The prototype is designed, simulated, and fabricated. A series of experiments are carried out and the results indicate that the maximum output thrust is 50.8 N at an excitation frequency and peak-to-peak voltage of 28.9 kHz and 120 Vp-p, respectively. The maximum force density is 247.8 N/kg.

The demand for energy-harvesting technology is steadily growing in the field of self-powered wireless sensor systems for use in pneumatic systems. The purpose of this research was to study an energy harvester excited by alternating air load in a pneumatic system. The harvester was designed to consist of a power chamber and a compressed chamber, and to the bottom of the power chamber a piezoelectric patch as been affixed. The harvester is excited by the changing pressure, which can be adjusted through changing volume, and the alternating air pressure energy can be harvested through the deformation of the piezoelectric patch. A test system was built and a prototype device was tested under various experimental conditions. The test results show that the energy generation performance of the harvester can be influenced by varying the volume compression parameters, with the output voltage increasing when the flow increases. The maximal output voltage and power are 24.7 V and 1.06 mW, respectively. An effective power of 0.28 mW was measured across the 200 kΩ resistor at a pressure of 200 kPa and a cycle time of 2.5 s with a flow of 150 L/min.

The hybrid joints of manipulators can be switched to either active (actuated) or passive (underactuated) mode as needed. Consider the property of hybrid joints, the system switches stochastically between active and passive systems, and the dynamics of the jump system cannot stay on each trajectory errors region of subsystems forever; therefore, it is difficult to determine whether the closed-loop system is stochastically stable. In this paper, we consider stochastic stability and sliding mode control for mobile manipulators using stochastic jumps switching joints. Adaptive parameter techniques are adopted to cope with the effect of Markovian switching and nonlinear dynamics uncertainty and follow the desired trajectory for wheeled mobile manipulators. The resulting closed-loop system is bounded in probability and the effect due to the external disturbance on the tracking errors can be attenuated to any preassigned level. It has been shown that the adaptive control problem for the Markovian jump nonlinear systems is solvable if a set of coupled linear matrix inequalities (LMIs) have solutions. Finally, a numerical example is given to show the potential of the proposed techniques.