摘要：A numerical procedure for hydrodynamic redesign of the conventional vaned diffuser into the low solidity vaned diffuser by means of a real-coded genetic algorithm with Boltzmann, Tournament and Roulette Wheel selection is presented. In the first part, an investigation on the relative efficiency of the different real-coded genetic algorithm is carried out on a typical mathematical test function. The real-coded genetic algorithm with Boltzmann selection shows the best optimization performance compared to the Tournament and Roulette Wheel selection. In the second part, an approach to redesign the vaned diffuser profile is introduced. Goal of the optimum design is to search the highest static pressure recovery coefficient and low solidity vaned diffuser. The result of the low solidity vaned diffuser optimum design confirms that the efficiency and optimization performance of the real-coded Boltzmann selection genetic algorithm outperforms the other selection methods. A comparison between the designed low solidity vaned diffuser and original vaned diffuser shows that the diffuser pump with the redesigned low solidity vaned diffuser has the higher static pressure recovery and improved total hydrodynamic performance. In addition, the smaller outlet diameter of designed vaned diffuser tends to a more compact size of diffuser pump compared to the original diffuser pump. The obtained results also demonstrate the real-coded Boltzmann selection genetic algorithm is a promising optimization algorithm for centrifugal pumps design.

摘要：Fast electron-hole recombination issues during titanium dioxide(TiO_(2))photocatalysis limit its application in preventing bacterial infection during bone defect *** this study,TiO_(2)@reduced graphene oxide(rGO)composites were synthesized using a hydrothermal method in which rGO,which possesses very high electrical conductivity,promotes the separation of photoelectron-hole pairs of TiO_(2),thus improving the efficiency of photocatalytic production of reactive oxygen species(ROS).Subsequently,TiO_(2)@rGO composites were introduced into poly-L-lactic acid(PLLA)to prepare bone scaffolds with photocatalytic antibacterial function via selective laser *** results showed that TiO_(2)grew on the surface of rGO and formed a covalent bond connection(Ti-O-C)with rGO.A decreased electrochemical impedance of TiO_(2)@rGO composites was observed,and the transient photocurrent intensity increased from 0.05 to 0.5μA/cm^(2).Analysis of electron spin resonance found that the photocatalytic products of TiO_(2)were·OH and·O^(2-),two kinds of ROS capable of killing bacteria via disrupting the structure of the bacterial membrane in *** experiments showed that the PLLA/TiO_(2)@rGO scaffolds had good antibacterial properties against Escherichia coli and Staphylococcus ***,we report that these scaffolds exhibited both enhanced mechanical properties due to the addition of TiO_(2)@rGO as a reinforcement material and good biocompatibility during cell proliferation.

摘要：The sensitivities of betavoltaic batteries and photovoltaic batteries to series and parallel resistance are *** on the study,an electrode pattern design principle of GaAs betavoltaic batteries is *** PIN junctions with and without the proposed electrode pattern are fabricated and measured under the illumination of ^（63）*** show that the proposed electrode can reduce the backscattering and shadowing for the beta particles from ^（63）Ni to increase the GaAs betavoltaic battery short circuit currents effectively but has little impact on the fill factors and ideal factors.

摘要：The design work of motional cable in products is vital due to the difficulty in estimating the potential issues in current *** this paper,a physics-based modeling and simulation method for the motional cable harness design is *** model,based on continuum mechanics,is established by analyzing the force of microelement in *** the analysis procedure,three coordinate systems：inertial,Frenet and main-axis coordinate systems are *** variable substitution and dimensionless processing,the equation set is discretized by differential quadrature method and subsequently becomes an overdetermined nonlinear equation set with boundary conditions solved by Levenberg-Marquardt *** the profile of motional cable harness obtained from the integral of arithmetic solution,a motion simulation system based on＂path＂and＂profile＂as well as the experimental equipments is *** the same parameters as input for the simulation and the real cable harness correspondingly,the issue in designing,such as collision,can be easily found by the simulation *** research obtains a better result which has no potential collisions by redesign,and the proposed method can be used as an accurate and efficient way in motional cable harness design work.

摘要：Current design rationale （DR） systems have not demonstrated the value of the approach in practice since little attention is put to the evaluation method of DR knowledge. To systematize knowledge management process for future computer-aided DR applications, a prerequisite is to provide the measure for the DR knowledge. In this paper, a new knowledge network evaluation method for DR management is presented. The method characterizes the DR knowledge value from four perspectives, namely, the design rationale structure scale, association knowledge and reasoning ability, degree of design justification support and degree of knowledge representation conciseness. The DR knowledge comprehensive value is also measured by the proposed method. To validate the proposed method, different style of DR knowledge network and the performance of the proposed measure are discussed. The evaluation method has been applied in two realistic design cases and compared with the structural measures. The research proposes the DR knowledge evaluation method which can provide object metric and selection basis for the DR knowledge reuse during the product design process. In addition, the method is proved to be more effective guidance and support for the application and management of DR knowledge.

摘要：Isotope source energy deposition along the thickness direction of a semiconductor is calculated,based upon which an ideal short current is evaluated for betavoltaic ***-hole pair recombination and drifting length in a PN junction built-in electric field are extracted by comparing the measured short currents with the ideal short currents.A built-in electric field thickness design principle is proposed for betavoltaic batteries：after measuring the energy deposition depth and the carrier drift length,the shorter one should then be chosen as the built-in electric field *** the energy deposition depth is much larger than the carrier drift length,a multi-junction is preferred in betavoltaic batteries and the number of the junctions should be the value of the deposition depth divided by the drift length.

摘要：A good cooling circle should ensure that the system can work at an appropriate temperature in the requirements of power increase,engine compartment constraint and working demands for modern engineering machinery,which asks for a thorough understanding of system thermal loads before practical ***,traditional experiment method spends a long time,costs a huge resource but lacks efficiency,whereas virtual design can avoid the shortcomings of traditional method and can analyze operating states adequately with variable loads on engine,generator,drives,battery pack and HVAC ***,this paper focuses on a new virtual design method based on multi-dimension coupled simulation adopting Flowmaster software for initial prediction and CFX tool for further *** simulation results in different operating conditions are compared and validated with *** experiment and range analysis are used to explore key parameters of cooling *** research will be helpful in guiding future design and optimization of engineering machinery.

摘要：We present a method for computed tomography(CT)image processing and modeling for tibia microstructure,achieved by using computer graphics and fractal *** the large-scale image data of tibia species with DICOM standard for clinical applications,we take advantage of algorithms such as image binarization,hot pixel removing and close operation to obtain visually clear image for tibia *** of these images are based on 20 CT scanning images with 30μm slice thickness and 30μm interval and continuous changes in *** each pore,we determine its profile by using an improved algorithm for edge ***,to calculate its three-dimensional fractal dimension,we measure the circumference perimeter and area of the pores of bone microstructure using a line fitting method based on the least ***,we put forward an algorithm for the pore profiles through ellipse *** results show that the pores have significant fractal characteristics because of the good linear correlation between the perimeter and the area parameters in log–log scale coordinates system,and the ratio of the elliptical short axis to the long axis through ellipse fitting tends to *** on support vector machine and structural risk minimization principle,we put forward a mapping database theory of structure parameters among the pores of CT images and fractal dimension,Poisson’s ratios,porosity and equivalent *** this basis,we put forward a new concept for 3D modeling called precision-measuring digital expressing to reconstruct tibia microstructure for human hard tissue.

摘要：V-shape hulls are widely used in peacekeeping efforts such as demining vehicles in order to deflect the blast energy and reduce the effects of mine blast. Blast resistant design and energy absorption enhancement of V-shape plates were carried out using finite element analysis package ABAQUS. Various geometries of V-shape plates with and without interlayer of materials like Al-foams and honeycomb were employed to analyze their effects on the deformation of the plate and applied stresses and strains. The results obtained show that application of metallic foams leads to better response of the plate and consequently results in more energy dissipation, less dame to vehicle and enhances crew survivability.

摘要：The conceptual design and optimization of a tilt-rotor Micro Air Vehicle(MAV) for a well-defined mission are performed. The objective of this design cycle is to decrease the design time in order to efficiently create a functional tilt-rotor drone. A flight mission is firstly defined for a tiltrotor MAV performing hovering and cruise flight scenarios. Secondly, a complex wing shape is chosen and modeled in order to determine the final shape. The initial shape is scaled in order to acquire an arbitrary wingspan of one meter. For the specific area and wingspan, the aspect ratio of the designed wing shape is found to be equal to 2.32. Thirdly, a constraint analysis of the MAV is performed by using an energy balance analysis for six different flight scenarios. This analysis yields the required power loading and wing loading. Fourthly, the weight of the vehicle is estimated using both statistical and computational methods. After estimating the total weight and the wing loading of the MAV, the surface of the wing is determined, yielding a final wingspan of 0.76 m. Subsequently, considering the total weight of the designed MAV, the needed lift coefficient is ***, using the lift coefficient in conjunction with XLFR5, a batch of airfoils is selected and analyzed to evaluate the aerodynamic coefficients of the wing with each airfoil. This analysis ultimately leads to the optimum airfoil being selected. Finally, design of the fuselage and tail, internal components selection, and servo-mechanisms design are carried out prior to a stability analysis. All these proposed steps are needed to design efficient and functional tilt-rotor MAVs.