Advanced Materials Research Vol. 739

Abstract: In order to obtain adequate water resources, the decision to build water reservoirs is unavoidable. However, the large amount of sand and rocks washed out from upstream shortens the lifespan of the water reservoirs. Therefore, the sediment needs to be cleared away to prolong the lifespan of the reservoirs, secure the water storage in the water reservoirs and improve their efficiency to achieve the best economic benefits. This research aimed to discuss the reasons for geographical and environmental change, as well as natural ecological destruction due to construction of water reservoirs. The findings could serve as a reference to further ecological engineering projects to restore ecological and geographical conditions, and to improve the land degradation situation caused by the construction of water reservoirs.

Abstract: Most analysis of global warming are seldom analyses the countries adaptability to the climate change but may have an impact on the strategy of tackling global worming. Even if considered the influence, just works with the simple static model and not the dynamic model to analyze. This study is considering adaptation that is crucial for the analysis of the pollutant control problems in the dynamic framework. We show that the optimal trajectory and stock in the global optimality and Nash equilibrium respectively.

Abstract: Nowadays, the international community pays attention to the climate change and environmental issues. The strategy of low-carbon tourism has gradually become a realistic choice for the tourism development in the every country. Qinghai Lake scenic area is the leading scenic area of tourism development in Qinghai Province and the key area of tourism development in western China. Therefore, the low-carbon development is the only way. This paper analyzes the necessity of low-carbon development in tourist scenic area, respectively from tourism development and construction, operation and management, tourism attractions, tourism production and tourism consumption, and then discusses the low-carbon development path in Qinghai Lake scenic area.

Abstract: A bump of irregular frame structure as an example, the use of ANSYS software, the structure dynamic characteristics analysis, given the cycle ratio and modal participation mass percentage, as the bump of irregular frame structure design reference.

Abstract: Classical hextremum problem to determine the optimum geometrical parameters of a linear-elastic, homogeneous, isotropic circular membrane with a rigid central disk is the static effect of a concentrated force is solved. Ratio of 0.326 found between the inner and outer radius of the membrane plate provides the greatest sensitivity, efficient thickness and minimum materials consumption, which is a consequence of the implementation of the condition of reliability for the safety factor for the down to the limit state of springing element. The energy failure theory of Huber-Hencky-Mises (Huber M.T., Hencky H., Mises R.) is used as the constraint equation. Due to the complexity (transcendence) of the formula target sensitivity function that depends on two controlled variables, the procedure of maximization is performed by search for the direct numerical method. The developed mechanical-mathematical model of the optimization process is based on three well-known conditions proposed by G. Kirchhoff for the thin plate-bending theory.The derived formulas can be used for optimal design of capacitive, inductive and strain measuring force sensory data unit, in which the membrane requires the greatest move, that is, high sensitivity, and the membrane plate is loaded only by the working pressure without experiencing reaction from the mechanism of the device.

Abstract: Gearing is one of the most critical components in mechanical power transmission systems.. This paper explains about the comparison of the geometry of spur gears for two different modules by modeling and mathematical equations, load distribution at various positions of the contact line and the stress analysis of spur gears using three-dimensional finite element method. The bending stresses were examined using three-dimensional finite element model.. These stresses of different modules obtained from the finite element analysis were compared and the considerable reduction of weight occurred was found and also the values are compared with the theoretical values. Both results agree very well. This indicates that the finite element method model is accurate.

Abstract: The purpose of this study was to verify the stresses induced by dental restoration on bi-material FEM alveolar bone model. Implanting induced stresses over the alveolar bone are studied during the past decades. With the improving computing technology, computer simulations with FEM( Finite Element Method) software are employed on investigating the stresses after the cure. An important issue about FEM calculations is the discretelized model. Single material bone model were adopt in the early stage studies. Due to the nature of human bone structure, the assumption of homogenous material over the bone is not an adequate one nowadays. Bi-material bone structure has become the mainstream of the numerical studies these years. The bones are modeled with a cancellous core surrounded by a dense cortical layer. Forces, stresses, deformations and strains are calculated by performing FEA on those digital bone models. However, the reliability of bi-material bones digital models is not verified. We built a bi-material prototype and an identical digital implanted bone model. Same boundary conditions and loads are applied on both models. The induced strains measured by strain gage agree with the computer calculated results well.

Abstract: LED has characters of small size, long life and low power consumption, and it is environmental friendly. These advantages make LED have a huge market in the lighting industry. LED with the light distribution design can meet the requirements of the application under different circumstances. With the acknowledgement of the principles of light distribution design, based on optical engineering software LightTools, we study the light distribution design of LED back light module for direct-down illumination and LED shadowless lamp. After the secondary optics light distribution design of the LED light, its transmittance and uniformity has been noticeably improved. We depict different types of micro-structure on the surface of 3mm thickness PMMA diffuser, test and analysis the optical properties of the diffuser under different microstructure.

Abstract: The shifted Chebyshev polynomials and Floquet theory are both adopted for the prediction regenerative chatter stability and Hopf bifurcation in milling. The influences of the system parameter on the stability of the milling system have been analyzed. The stability lobe diagrams are obtained. The result shows that the shifted Chebyshev polynomials method is more accurate than the semi-discretion scheme for spindle speed lower than 3500 round per minutes. The stability in milling can well be predicted by the cutting depth and feed rate lobes diagrams. Only Hopf bifurcations are detected by the Eigen-value analysis. The stable solution transform from the stable equilibrium point to the quasi-periodic oscillation after Hopf bifurcation.

Abstract: This document explains and demonstrates the composing of power losses of MOSFETs in DC/DC converters which are based on Single-ended Forward topology and Resonant Reset technology and how to calculate the losses by equations. For the purpose of validating the correctness of these equations, two different MOSFETs are chosen and uesed in the same DC/DC converter. Furthermore, some practical method is presented in choosing the most suited MOSFETs for certain DC/DC converters.