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Gradient-porous Titanium alloys can be applied to manufacturing implants for bone replacement, due to their good biological and mechanical compatibility. In this work, the feasibility of fabricating gradient-porous Titanium by centrifugal deposition and vacuum sintering was investigated. The apparent porosity of the gradient-porous Ti examined by Archimedes method is 56%. And the open pores occupy 89%. The pore structure was observed by an optical microscope. And its porosities at different radius were calculated by image software based on optical microscopic images. In addition, a nanoindentation was employed to characterize the mechanical properties at different radius. The results showed that the porosity of the sample increased with increasing of radius. Besides, both the elastic modulus and hardness changed alone radius with a same trend.

A novel path-following control method of under-actuated AUV is proposed in this paper. Under the Serret-Frenet coordinate system, dynamics equations of path-following error were established based on virtual target AUV. And then combined with dynamics equations of AUV, controller was designed based on Lyapunov stability theory and backstepping technique. Simulation results showed that path-following error could converge to zero rapidly by using the proposed non-linear feedback control law, to make the AUV navigate along the referenced path.

We study the strong stability of linear forms of pairwise negatively quadrant dependent (NQD) identically distributed random variables sequence under some suitable conditions. To overcome the weakness of collaborative services ability in different grid portal, a new grid portal architecture based on CSGPA (Collaborative Services Grid Portal Architecture), is proposed. This paper aims to enhance the performance of PSO in complex optimization problems and proposes an improved PSO variant by incorporating a novel mutation operator. The results obtained extend and improve the corresponding theorem for independent identically distributed random variables sequence.

In order to make full use of texture features of image when fusing images, and taking into account the inherent advantages of fractal theory in this respect, a novel image fusion algorithm, which used fractal dimension and directional contrast, based on multi-wavelet transform was proposed in this paper. So, we put forward a new design of the intelligent lock which is mainly based on the technology of wireless sensor network. Particle swarm optimization (PSO) is a recently proposed intelligent algorithm which is motivated by swarm intelligence. PSO has been shown to perform well on many benchmark and real-world optimization problems; it easily falls into local optima when solving complex multimodal problems. Moreover, the objective indexes, which are image entropy, standard deviation and quality measure, were adopted to evaluate the comparative results of evaluating fusion quality. To avoid the local optimization, the algorithm renews population and enhances the diversity of population by using density calculation of immune theory and adjusting new chaos sequence.

This paper presented the key techniques development of motor/generator (M/G) for the FES system in recent years, and summarized the latest developments of three machines such as: induction machine (IM), reluctance machine (RM) and permanent magnet machine (PMM) including traditional structure PMM and Halbach structure PMM, which now widely used in the FES system. The characteristics of three machines had been compared and analyzed, which provides guidance for the FES field researchers to choose appropriate M/G.Then the comparison of spectra of the sequences respectively interpolated by FDIA and commonly used interpolation algorithm is conducted, which affirms the superiority of FDIA. Finally, an effective method of achieving best decimation of the sequence interpolated by FDIA is provided. All these lay primary theory foundation for the application of Zadoff-Chu sequence to HF channel sounding.

Because the traditional linear vectorization methods have some shortcomings including processing data slowly, being sensitive to noises and being easy to be distorted. Fuzzy rules and its inference mechanism are the assurance of achieving feature fusion. However, the self-learning function of FNN could train its weights; it is difficult to optimize fuzzy rules. Besides, the common FNN training algorithms have low constringency speed and are liable to run into the local optimization.PSO algorithm has high convergence speed and it is simpler on the operation and is more potential on optimizing FNN. Thus, PSO algorithm could be adapted to train FNN weights, and prune the redundancy links, optimize fuzzy rules base. In the paper we present an improving immune genetic algorithm based on chaos theory. The over-spread character and randomness of chaos can be used to initialize population and improve the searching speed, and the initial value sensitivity of chaos can be used to enlarge the searching space. To avoid the local optimization, the algorithm renews population and enhances the diversity of population by using density calculation of immune theory and adjusting new chaos sequence.

In order to resolve these problems, we put forward a new design of the intelligent lock which is mainly based on the technology of wireless sensor network. Particle swarm optimization (PSO) is a recently proposed intelligent algorithm which is motivated by swarm intelligence. PSO has been shown to perform well on many benchmark and real-world optimization problems; it easily falls into local optima when solving complex multimodal problems. To avoid the local optimization, the algorithm renews population and enhances the diversity of population by using density calculation of immune theory and adjusting new chaos sequence. The paper gives the circuit diagram of the hardware components based on single chip and describe how to design the software. The experimental results show that the immune genetic algorithm based on chaos theory can search the result of the optimization and evidently improve the convergent speed and astringency.

There are many factors that can affect network performance, such as delay, packet loss and capacity utilization. A Wireless-Optical Broadband Access Network (WOBAN) is gaining more attention because its good performance and merits such as reliability, robustness and high capacity as well as flexibility. In this paper, we proposed the Flow Limited and Risk Aware Routing Algorithm (FLRAR), which takes capacity utilization and link failure into account. And we also used Link Success Rate (LSR) to detect the link failure and redirect the related packets. The research results show that the process of information fusion has abilities of adapting and self-learning.

HF channel sounding requires perfect autocorrelation property of the sounding sequences. Compared with other pseudonoise sounding sequences, Zadoff-Chu sequence gets great attention due to its predominant periodic autocorrelation property. A Wireless-Optical Broadband Access Network (WOBAN) is gaining more attention because its good performance and merits such as reliability, robustness and high capacity as well as flexibility. There are many factors that can affect the network performance, such as delay, packet loss and capacity utilization. Application examples show that, this system can significantly improve the efficiency of aerodynamic design.

There are many factors that can affect network performance, such as delay, packet loss and capacity utilization. Vehicle handling directional stability has been more and more important, experiments for steering wheel corner step input response, steering oil tank response property, steady state turning and steering angle of all steering wheels were conducted in this paper, the experimental results show that multi-wheel steering system can fulfill its function very well and reach target angle, it provides a new method for researching for the vehicle handling directional stability.

In order to adapt the spectrum property of Zadoff-Chu sequence to the requirement of HF channel sounding transmitter-receiver, the Formula Direct Interpolation Algorithm (FDIA) is put forward by which the amplitude frequency characteristic of Zadoff-Chu sequence can be enhanced. Then the comparison of spectra of the sequences respectively interpolated by FDIA and commonly used interpolation algorithm is conducted, which affirms the superiority of FDIA. Finally, an effective method of achieving best decimation of the sequence interpolated by FDIA is provided. All these lay primary theory foundation for the application of Zadoff-Chu sequence to HF channel sounding.

HF channel sounding requires perfect autocorrelation property of the sounding sequences. Compared with other pseudonoise sounding sequences, Zadoff-Chu sequence gets great attention due to its predominant periodic autocorrelation property. In order to adapt the spectrum property of Zadoff-Chu sequence to the requirement of HF channel sounding transmitter-receiver, the Formula Direct Interpolation Algorithm (FDIA) is put forward by which the amplitude frequency characteristic of Zadoff-Chu sequence can be enhanced. Application examples show that, this system can significantly improve the efficiency of aerodynamic design.

Public rental housing is an important part of China’s low-income housing system. Through on-site investigations and questionnaires in housing projects in Changsha, China, it was found that the current public rental housing has made a great progress, but also exists a series of problems, such as: too much focus on the construction other than the management afterwards; the inefficiency of laws and regulations, the lack of public facilities, inexperience of management and so on. Suggestions are given as: laws and regulations needs to be improved; outstanding facilities management companies should be encouraged to join the management, providing diversified and personalized facilities management services, and more professional trainings and cooperation is urgently needed.

Extended producer responsibility (EPR) system is an environmental protection strategy to recycle end-of-life products. A dynamic analysis model between the government and the reverse supply chain (RSC) system operated under the EPR instrument was established. Game theory was applied to analyze the optimal fiscal policy of the government and the optimal decision of the participating enterprises. It concludes that governments environmental regulation is effective to improve the manufacturers remanufacturing rate and the recyclers effort-extent.

DC bias widely exists in power system. In order to analyze its influence on metering current transformer (MCT), a new digital simulation model based on Preisach theory is constructed firstly. Using this digital model, the ratio error and angle error of a running MCT are calculated under different levels of DC bias. Simulation results show that the current DC bias in power system has only little influence on the error of MCT.

A generalized higher-order global-local theory was presented. The transverse shear stresses can be got directly through the constitutive equation without using the equilibrium equation. The second derivative of interpolation function was deduced. The hammer integration of triangular area coordinate method was applied to solve the multiple integration problem of the element stiffness matrix. The order choice of numerical integration was discussed and results obtained through two different integration orders were compared. The flow of how to compile a FORTRAN program was given. A moderately thick composite laminated plate was analyzed via finite element method (FEM) based on the theory and results were compared with that of Paganos three-dimensional elasticity. It shows that the interlaminar stresses are accurate for moderately thick laminated plates.

According to geological characteristics and the occurrence of heavy oil properties in the northern Tibetan plateau, the development feasibility studies and risk analysis were carried out . A detailed examination of the effects of diagenesis were conducted in terms of microcopic observation , stratigraphic facies and other low permeability reservoir aspects. The main factor affecting reservoir properties was theorized. Finally, the reservoir development risk is illustrated. Measures of the reservoir protection and efficient exploitation were presented. The results show that diagenetic compaction and cementation makes greate impact on the reservoir properties distribution .And it is recommended to use the steam stimulation method test mining , the method is less investment , the technology is simple , fast yield , good economic returns .

This paper firstly analyzes the situation of forest biomass power generation in China. Then the environmental cost of forest biomass power generation is quantitatively accounted in the base of environmental value standard and the advantages of forest biomass power generation are presented through comparing environmental cost between forest biomass power generation and other various power generation forms. In the end, competitive power of forest biomass power generation is preliminary studied and the paper concludes that the competitiveness of forest biomass power generation is reduced automatically without complete internal accounting for environmental cost.

To meet the demand of communication automation for outfield equipment test module, special embedded system was proposed by combing host computer control board and signal acquisition board, taking advantage of high data transmission efficiency on PC104 bus. Multichannel switch, signal recuperation circuit and Analog to Digital Converter (ADC) were controlled by FPGA logic on signal acquisition board. Signal data acquired were transmitted to host computer control board to display for user in real time. Application shows that the system was easy to operate. It performs well on real time ability and stability.

In this paper, BiFeO3 (BFO) films were grown on LaAlO3 (LAO) substrate by a RF magnetron sputtering system. Fabrication parameters, such as work pressure, sputtering atmosphere, and post annealing were examined in terms of their influences on characteristics of the ferroelectric films. X-Ray diffraction, Raman scattering and scanning electron microscope measurements were employed to characterize the microstructure and the morphology of these films. At last, the ferroelectric characteristic of BFO has been studied, and the film has a large saturated polarization of 40 μC / cm2 under an applied field of 12 kV /cm.

The single-phase multiferroic Bi1-xSbxFeO3 ceramics were fabricated using traditional solid phase reaction technique and the effects of Sb3+ doping on their crystal structure and ferroelectric behavior were studied. X-ray diffraction (XRD) measurement revealed that 830°C is an appropriate sintering temperature for forming a pure-phase of Bismuth ferrite structure. The average crystalline grain size of doped ceramics becomes smaller as the doping concentration x increases. The leakage current of doped sample was much reduced compared with that of BFO. The electric hysteresis loops were obtained in the Bi1-xSbxFeO3 (x=0.02), and the residual polarization and saturated polarization are 0.03 μC/cm2 and 0.337 μC/cm2, respectively.

An cost effective, and simple method of preparation of surface modified graphene has been described in this work. Graphene oxide (GO) was synthesized from flake graphite by following a modified Hummers’ method. In comparison with other strong reducing agents used in GO reduction, we found thioglycolic acid (TGA) has its unique advantages in forming stable water dispersion of reduced GO. Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS) analysis confirmed the successful reduction of GO to graphene. Scanning electron microscopy (SEM) images of the product confirm the presence of thin sheets.

Intelligent vehicle is a preferable way for dealing with transportation problems. In cross-country environments, no apparent roads could be found, instead boscage, bumps and hollows, scattered materials make it hard to choose suitable paths. Path planning is a combinational optimization issue to find out a short path from many candidates. A combinational optimization algorithm was adopted to solve the problem. A multi-scale grid environment modeling mechanism was designed to model the unordered and irregular environment by a standard grid map. Then an ant colony optimization based algorithm was presented for finding out the most suitable path from the map. The algorithm introduced a local optima breaking mechanism based on early convergence judging process to avoid falling into local optima. Three criteria were designed for the process, say criteria of single grid, of static colony and of dynamic convergence. Feasibility and effectiveness of the method were verified by experiments.

Core test data from 10 wells indicate that the sandstone reservoir in Yuanshi oilfield is characterized by low permeability, thin pore throat, high clay mineral content, and strong sensitivity, which are likely to cause reservoir damage and affect development result. Based on the characteristics of water-sensitive, velocity-sensitive low permeability reservoir as well as non-Darcy flow behavior, the development strategy of high pressure water injection and cyclic water injection has been formulated with the assistance of engineering measures such as fracturing and reducing well spacing.

In this paper, a temperature field model of 45 steel shafts during the laser quenching was built and simulated by using ANSYS software. Its surface temperature distribution of the shaft during the laser beams scanning was simulated. Their effects of different laser power, laser beams spot size and scan speed on part’s quenching performance were analyzed.

Based on the energy recycle ideas, in view of the three-level green supply chain (GSC) including a manufacturer, a processor and a collector, the manufacturer-leading Stackelberg models were established with random recycling. The rewards and punishments contract between the manufacturer and the processor was designed, and the influences of the proposed mechanism to the game parties’ optimal strategies were discussed. The research shows that implementation of the rewards and punishments mechanism is effective to improve the effort-level for recycling end of life (EOL) product, and increase the processing rate of EOL product. The conclusions are helpful to guide the formulation and implementation of the strategy of sustainable development in China nowadays. In addition, the research has great realistic significance for instilling the consciousness of environmental protection.

In this paper, WC particles and NH4HCO3 powders were mixed evenly, and then pressed under 150MPa. The WC porous preforms were obtained after the compacts being heat treated to eliminate NH4HCO3. The volume ratios of WC in the preforms were 30%, 40% and 50% respectively. WC/Fe composites were fabricated by infiltrating liquid cast iron into the WC porous preforms. Optic microscope and scanning electron microscope were employed to observe the microstructure of the matrix alloy and the composites. The results showed that matrix alloy without WC addition had pores in the surface. The microstructure of the composites with WC volume fractions of 30%, and 40% were denser than that of 50%. Hardness and wet sliding wear behaviors of the composites were investigated at room temperature. The addition of WC particles could effectively improve the hardness and the wear resistance of the composites. The influence of volume fractions on hardness of the composites was similar to that on wear resistance. The hardness and the wear resistance of the 40vol.%WC/Fe composite was better than those of the 30vol.%WC/Fe composite. And the properties of the 50vol.%WC/Fe composite were the worst.

Optimal flight path is restricted within Minimum Threat Surface (MTS). With Taylor’s expansion, the horizon projection of 3D flight path within MTS is fitted with a polynomial function with finite items. So the original path planning problem is simplified to search the optimals values in the coefficient space of the polynomial function. Flight path cost model of flight path is built and PSO is applied to search optimal coefficients. Flow of optimization is introduced and validated with three simulation cases. Simulation results show that MTS and PSO can effectively solve global optimization of 3D flight path.

In order to evaluate the air-to-surface missile bearing-only attack effect u, the paper introduces a method which is based on EspCreator platform to develop the virtual reality simulation system. The 3D geometric models of the sea view、fighter plane、 air-to-surface missile and the target battleship are established by the 3D Max. The visual simulation of ASM Attack under bearing-only target indication is developed on the EspCreator simulation platform. The shared memory technology is applied in visual scene parameter driving and the technology of integrating DirectX API into scene loop is applied for the real-time simulation of the radar beam. The simulation system can modify the parameters easily and intuitive display simulation results. It’s a new convenient approach for research and evaluation of the weapon application simulation.

Measuring the relative distance, relative speed and target acceleration under knowing only angular information is called a "passive track" problem to target. Because of the noise in measuring result, it is necessary to describe a "passive track" problem by nonlinear random system. This paper researches optimal end guidance law about target-seeking UAV under passive guidance. As a simulation result, optimal end guidance law attacking fixed target is superior to constant coefficient proportion guidance law.

Molten iron corrosion resistance of silicon-corundum-silicon nitride composites were investigated using corundum, silicon nitride, clay and silicon powder as the main starting materials by static crucible method. The corrosion mechanism of the composites was analyzed by means of scanning electron microscope (SEM with EDS). The results revealed that corundum-silicon nitride composites possessed good molten iron corrosion behavior and the active oxidation of silicon nitride was the main reason for loose structure of the corroded specimen; The composites produced a dense layer by addition of silicon, which made superior molten iron corrosion resistance behavior.

On the basis of previous studies, the structural model of spacer fabric composites were built by using the finite element software ANSYS for analyzing the compressive properties in the paper. The compressive features of the composites were analyzed, and the influence of pile height, pile density and poisson ratio on the compressive properties was studied too. The results revealed that the maximum value of the stress appeared in the interface between the piles and the face-sheets when the spacer fabric composites were subject to compressive loads, in which the composites damaged easily. Another maximum value of the compressive stress occurred in the cross of the “8”-shaped piles, where the piles damaged easily too. And the minimum value appeared in the upper and lower face-sheets, which indicated that the damage didn’t occur easily in the face-sheets. The compressive properties of the spacer fabric composites increased with the increase of the pile density and poisson ratio, and decreased with that of the pile height. The study provides a reference for the structural optimum of the spacer fabric composites.

To simulate the deformation for soft objects, proposes a local deforming method based on surface area-preservation. The cylinder mesh is employed as the basis mesh to bypass its build step and to uniform the deformation algorithm. The damping curve is employed to simulate the gofferes appearing in the inside section of surface. The gofferes can improve greatly the deformation results. Surface area-preservation and detail-preservation are achieved to improve the authenticity of deformation. The method has been proved feasible and valid to simulate the bending deformation for soft object by experiments results.

Feature spaces optimization plays a very important role in object recognition and categorization. After analyzing of several fashionable local features at present, some optimization algorithms based on the information theory are proposed. In this paper, we describe the approaches to recognize generic objects using these features which have been optimized. As baselines for comparison, we also implemented some additional recognition systems using other optimization algorithms. The performance analysis on the obtained experimental results demonstrates that the proposed optimization algorithms are effective and efficient.

A series of gels with 3Al2O3•2SiO2 were prepared by Sol-gel method and heated at several temperatures for 2 h to synthesize Ti, Fe-doped mullite. The powers were characterized by differential thermal analysis (DSC-TG) and X-ray powder diffraction (XRD). Phase separation was promoted by doping both TiO2 and Fe2O3; with increasing the amount of dopant ions the formation temperature of Si-Al spinel decreased and the formation temperature of mullite increased by TiO2 doping but decreased by Fe2O3 doping. The formation temperature of pure mullite was about 1250-1350 °C.

To solve partner selection problems under enterprise’s green operation strategy nowadays, a new fuzzy-AHP method based on the AHP and basic theory of the triangular fuzzy number was given. Moreover, the evaluation hierarchy structure and corresponding evaluation process were described. Compared with traditional AHP approach, the proposed model combines subjective analysis with quantitative analysis more reasonably, synthesizes group opinions more adequately. The method can be practiced easily and widely, mainly because of the model’s simple, normative arithmetic formulas and the consistency of triangular-fuzzy-number-based judgment matrices. The results of a case study on selecting fabric suppliers in a middle-scale clothing enterprise indicate that, by applying the method-based software system, fair and reasonable conclusions under group decision-making environment can be acquired clearly.

In this work, the feasibility of using planetary ball milling for coating bearing balls with a self-lubricating film was investigated. Bearing balls with appropriate amount of MoS2 powder were put into vacuumed stainless steel vials and ball milled. With proceeding of ball milling, thickness of the self-lubricating film increased at first and then decreased. X-ray diffraction (XRD) and X-ray photoelectron spectrum (XPS) results revealed that the surface of the self-lubricating film was MoS2 and the inner region was a mixture of iron molybdenum alloys (Fe3Mo, FexMoy), MoS2 and FeS. Friction coefficient between the self-lubricating film and bear steel was 0.06~0.1.

Power transformer is one of the most important electric equipments in power network, its running state has a direct effect on its safe operation of power network. Fault’s occurrence of power transformer probably result in vast hazards or accidents. According to statistics, its over-temperature operation of winding often result in different fault patterns, such as aging, breakdown and its burnt, etc, which has a large proportion in its accidents of power transformer. In this paper, based on the thermal analysis theory, a 3D thermal field model of transformer’s winding and core is respectively established in ANSYS software environment. And its 3D temperature field distribution of power transformer, including winding and core is simulated. Numerical simulated results provide a reliable and convenient reference for its thermal performance analysis of power transformer.is simulated. Numerical simulated results provide a reliable and convenient reference for its thermal performance analysis of power transformer.

Joining Cu to Al has been carried out by vacuum contact reactive brazing without filler metal. Experimental results obtained showed that the eutectic structure and some Cu-Al intermetallic compounds were the main phases of the braze seam. The fracture surface of the joint presented typical brittle fracture for the existence of intermetallic compounds at the interface and the shear strength could reach 65MPa.