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Pr doped SnO2 particles as negative electrode material of lithium-ion battery are synthesized by the coprecipitation method with SnCl4·5H2O and Pr2O3 as raw materials. The structure of the SnO2 particles and Pr doped SnO2 particles are investigated respectively by XRD analysis. Doping is achieved well by coprecipitation method and is recognized as replacement doping or caulking doping. Electrochemical properties of the SnO2 particles and Pr doped SnO2 particles are tested by charge-discharge and cycle voltammogram experimentation, respectively. The initial specific discharge capacity of Pr doped SnO2 the negative electrode materials is 676.3mAh/g. After 20 cycles, the capacity retention ratio is 90.5%. The reversible capacity of Pr doped SnO2 negative electrode material higher than the reversible capacity of SnO2 negative electrode material. Pr doped SnO2 particles has good lithiumion intercalation/deintercalation performance.

Aiming to investigate the effects of custom-made and thread dental implant systems on the stress distribution in alveolar bone using linear analysis of the finite element method (FEM). Two types of systems: the custom-made implant and the thread dental implant system, were studied using a three-dimensional finite element analysis (3D FEA). Comparing the parts of all systems for loading in different directions, the stress and deformation distribution in custom-made implant and alveolar bone are better than that in thread dental implant system. The analysis data definitely demonstrated the difference in stress and deformation distribution of components in different dental implant systems. Results show the custom-made implants are provided with more advantages and can be used in future experiment and clinical test.

In this paper, we investigate Device-to-Device (D2D) communication underlaying cellular networks to provide spectrally efficient support of local services. Since in underlay mode, D2D communications share resources in the time and frequency domains with cellular system, it will introduce potentially severe interference to the cellular users and accordingly presents a challenge in radio resource management. In order to avoid generating interference to the high-priority users (cellular users) operating on the same time-frequency resources and to optimize the throughput over the shared resources under the transmit power and the quality of service (QoS) constraints, we propose an interference alignment-based resource sharing scheme for D2D communication underlaying cellular networks. The simulation results demonstrate that by using the proposed scheme, D2D communication can effectively improve the total throughput without generating harmful interference to cellular networks.

This paper focuses on the construction quality control of broadened roadbeds and all structure layers of pavements, proposes construction control methods and corresponding treatment measures, combining the design features and the main points of construction of some provincial roads project, aiming at the asphalt pavement longitudinal cracking in highway reconstruction.

With energy and environmental issues are increasingly becoming the focus of global attention, building energy efficiency is one of the basic strategic planning for sustainable development in China, it is developing rapidly, and gets impressive results. Nevertheless, the building energy saving in our country that what has a lot of questions. For this reason, virtual simulation technology is made full use in building energy-saving and made practical engineering application analysis, a new method will be sock in building energy-saving design.

With ever increased demand for reduced sizes and increased complexity and accuracy, traditional machine tools have become ineffective for machining miniature components. Typical examples include dental implants, the parts used in mechanical watch movement, and the parts used in medical endoscope. With complex geometry and tight tolerance, few machine tools are capable of making them. This paper introduces our PC-based CNC Turn-Mill Machining Center. It has 5 axes, an automatic bar feeder, an automatic part collection tray, and a tool changer. In particularly, it has a special synchronization control algorithm that gives not only higher accuracy but also ease of use. In addition, to improve the accuracy, the software based volumetric error compensation system is implemented. Based on the experiment testing, the machining error is ± 3 µm in turning, ± 7 µm in milling and the maximum profile error is less than ± 7.5 µm in gear hobbing.

In this paper, we study positive solutions to the repulsive singular perturbation Hill equations with impulse effects. It is proved that such a perturbation problem has at least one positive impulsive periodic solution by a nonlinear alternative of Leray--Schauder.