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Sintering is a vital technology used for consolidation of metal and ceramic powders. The process is generally long and energy consuming because of the way in which heat transfer happens in electrical and gas furnaces. This study focuses on optimizing the sintering process of metallic powders, in particular titanium, using high frequency induction heating as alternative sintering method. Using electromagnetic induction and the associated Eddy current effect, the heat is generated directly into the electrically conductive object. Consequently, faster heating rates and lower heat loses are achieved. The purpose of this study is to understand the effect of process parameters, such as the powder compact density, on the efficiency of the induction heating and the properties of the sintered materials. The average heating rates recorded while heating to 1300oC are in the range of 3.5o to 15.3o C per second. Significant densification and consolidation, evident by the amount of closed porosity and increase in tensile strength was found in spite of the short heating time. The results show that the powder compact density plays a crucial role on the heating efficiency as well on the properties of the sintered material such as final density, porosity distribution and tensile properties. The samples with higher initial density showed tensile strength and ductility values comparable to those of high vacuum sintered and those specified by international standards for powder metallurgy Ti products.

High strength, low density, good corrosion resistance and biocompatibility is the combination of properties that Ti and its alloys can provide for engineering applications. Its costs are the most important limiting factor for the widespread use of Ti. Cost reduction for Ti alloys can derive from the use of cheaper alloying elements as well as the use of alternative manufacturing techniques. In this study binary Ti-X alloys (where X = Cu or Mn) were formulated and produced using the conventional powder metallurgy route of pressing and sintering. These chemical elements were selected because they are β stabilisers and can be used to create α+β Ti alloys. The study shows that with the techniques and processing parameters used handable products without delamination can be pressed. Moreover, chemically homogenous materials with density and mechanical property values comparable to those of other wrought-equivalent Ti alloys produced via powder metallurgy were achieved.

In this paper, the TiAl/Ti laminated (MIL) composite was fabricated via hot-pack rolling of the as-forged Ti-43Al-9V-0.3Y (at.%) plates and commercial Ti6Al4V (wt.%) sheet at 1250°C and then annealed at 90°C for 6 hours. The composite was analyzed by XRD and SEM techniques, respectively. Results showed that the interface between Ti and TiAl in the composite was consisted of four different microstructure areas and the phase constitutions for each area were: area 1: acicular β-Ti and α2 phase; area 2: acicular α2 phase; area 3: acicular α2 phase and B2 matrix; and area 4: acicular γ, α2 phase and B2 matrix. The fracture toughness of the TiAl/Ti MIL composite was tested, showing that the KIC value was about 38.35MPa·m1/2 at room temperature and higher than that of the pure Ti-43Al-9V-0.3Y alloy, which had a value of about 24.72 MPa·m1/2. The possible toughening mechanism for the TiAl/Ti MIL composite was discussed.

Vacuum-sintered billets of Ti-6Al-4V alloy from powder blend were extruded at two different temperatures: 1150 °C and 950 °C. The extruded material at 1150 °C was subjected to various heat treatments to obtain different microstructures: annealing in the β phase, β solution treatment and aging and α+β solution treatment and aging. The materials processed were characterised using scanning electron microscopy, X-ray diffraction and the mechanical properties were measured by tensile test. The microstructure of both extrusions are fairly similar, consisting of lamellar colonies, and the mechanical properties are also comparable, with yield strengths of about 1000 MPa, ultimate tensile strength of about 1100 MPa and elongation at fracture of 8-9%. The β annealing treatment, through coarsening the lamellar microstructure, reduces the strength of the alloy while keeping a high ductility. Both solution treatments and aging, which produces aged martensite and aged martensite and primary alpha, respectively, increases the strength and reduces the ductility. There is a trade-off between ductility and strength when it comes to tailoring the microstructure, and the as-extruded Ti-6Al-4V condition is the one with the best balance between strength and ductility.

According to the geometric optics, off-axis parabolic mirrors are used in terahertz time domain system for focusing the terahertz pulse. Theoretically, the focus of the parabolic reflector to eliminate the effects of spherical aberration, but a very high sensitivity to its optical axis misalignment, subtle misalignment will reduce the focal spot quality and therefore the need for precision optical axis adjustment is important. This article discusses terahertz time-domain spectroscopy system adjustment method in four off-axis parabolic mirror, after many experiments have proved feasible. In this work, two optical path adjustment methods were analyzed. The first approach is based on adjustment of spot shape from collimation and focus. In the second method, depend on the principle that the incident light path is different from reflected light path in parabolic cross section. Through testing this two methods have been proved feasible.

In this paper, we propose a real time method to detect vehicles on road by using a vehicle mounted monocular camera. Based on lane detection design, low time cost and high accuracy vehicle detecting and tracking algorithm is achieved. Robust and fast lane detection has been achieved using Hough transform in combination with a line merging method. The lane data are used for effective vehicle hypothesis generation. A subsequent validation, based on the area ratio of hypothesis vehicle, is used to eliminate false positives. Further, a data fusion mechanism is proposed to incorporate temporal information for stably updating vehicle detection results over time. Experimental results show that, without specific hardware and software optimizations, our method is able to detect vehicles on road with low false alarm rate at real time speeds of 30 frames per second.

For the common highway bridge strengthening works, this article divides the evaluation of bridge strengthening works into three categories layers - durability, safety and suitability, to evaluate the bridge strengthening from a technical level. Then analyzed separately for each category layer, select the parameter indices which have an important influence on each category layer to be the evaluation indicators. When evaluating the safety and suitability, the durability has been taken into consideration to amend their evaluation scores. On the basis of the obtained scores of the category layers, by using the Analytic Hierarchy Process method and the weighted average method, we can get the evaluate score of the members, components, parts entirety and the entirety of bridge successively. Proposed a kind of post-evaluation method applies to the common highway bridge reinforcement. This post-evaluation method provides theoretical references for the effect post-evaluation bridge reinforcement.

At present, in the digital audio processing sampling rate is respectively 32 kHz, 44.1 kHz, 48 kHz [1]. Because of the different criteria, there is much inconvenience in the process of research. Therefore, the sampling rate converter is a must, between any two kinds of sampling rate. In synchronous sampling rate conversion, you can use decimation and interpolation for sampling rate conversion, but in the asynchronous sampling rate system, due to the different input clock pulse with the output clock pulse, the above method cannot achieve. Therefore we introduce the fractional delay filter sampling rate conversion. This article introduces the principle of the sampling rate conversion and the fractional delay filter based on Farrow structure. At last, we simulate asynchronous sampling rate conversion of audio signal through the MATLAB.

Formation mechanism of high-angle reverse faults has always been one of the questions concerning structural geologists. The mechanics of high-angle reverse faults does not conform to the Mohr-Coulomb criterion or Anderson’s theory of faulting. Geologists tried to explain the formation mechanism of high-angle reverse faults by inversion structure theory, Maximum Effective Moment Criterion and fault-valve model and so on. It is hard to explain the mechanism of high-angle reverse faults in Sanan oilfield with these viewpoints. It is considered that the cause of formation of such high-angle reverse faults was that the dip direction of normal fault plane has been overturned by the intensive superposed folding and interlayer gliding. “Overturned fault dip” can be regarded as a new type of inversion structure and supplements the existing types of inversion structure.

A high precision, rapid and automatic high-voltage capacitor charging system is needed for pulse power system. A charging system based on high-voltage capacitor bank as energy storage device and c8051f020 MCU as control system, is designed in this paper .The hardware of this system includes a voltage measurement and control circuit, operation and display screen circuit, optical coupling circuit, fiber optical transceiver circuit. The software of this system uses closed-loop control algorithm to control the motor of voltage regulator, and the voltage of high voltage capacitor is charged from 0 to 20KV. By analyzing for the data of experimental and adopt the method of curve fitting, a modified voltage control algorithm is established. The modified algorithm improves the accuracy of charged voltage for high voltage capacitor to more than 99%.

LED driver plays an important role in unleashing many advantages of LED, such as high efficiency, long life-time. A constant current fly-back LED driver based on TOP222 is designed in this paper, and the transformer of the constant current power supply and the constant current feedback circuit are deeply researched. The experiment shows that, the output current of the LED driver is 1A, the output power is 10W, the power supply works in constant voltage mode within the low load situation. The result shows that the driver featured with good stability, constant-current characteristic, and high efficiency, is capable for driving LED.

This paper introduces a new type of matching toolshotcrete machine booster manipulator which is used to support tunnels and roadways under the mine. The working principle, feed mechanism and operating mechanism of shotcrete machine booster manipulator are mainly described in this article. Moreover, some key factors should be considered in the design process, which can achieve better jet effect.

A UV curable hybrid system with a dual mechanism of radical and cationic photo-polymerization, was investigated. A kind of free radical oligomer with low viscosity named hexahydrophthalic acid diglycidyl acrylate was first synthesized. The structure of the oligomer was characterization by FTIR. The UV curing processing of hybrid system was traced by real-time FTIR, and compared with free radical, cationic system. Thermal decomposition temperature and glass transition temperature of UV curing film for various system were determined by thermogravimetric analysis (TGA) and differental scanning calorimetry (DSC), respectively. And physical and mechanical properties of those curing films were analyzed and compared. The results show that the radical polymerization of double bond and cationic polymerization of epoxy group could occur simultaneously in hybrid system. The conversion rate of epoxy group for hybrid system was higher than that of epoxy group for cationic system, which demonstrated that the cationic photo-initiator (DPI·PF6) can be sensitized by the free radical photo-initiator (Irgacure 184). Compared with free radical and cationic system, the hardness and mechanical properties of hybrid system curing film were better than those of the cationic system curing film, while closed to those of free radical system.

Aqueous polyurethane(PU) polyols were synthesized from polyester polyol, toluene diisocyanate(TDI), dimethylolbutyric acid (DMBA) and diethanolamine(DEA). The structure of PU polyol and resulting polyurethane film were confirmed by the Fourier Transform Infrared Spectroscopy (FT-IR). The effects of NCO/OH and DMBA content on the particle size of PU polyol and resulting polyurethane films, which formed by the mixture of PU polyol and water-dispersible polyisocyanate, was investigated by dynamic light scattering analysis, dynamic mechanical analysis and measurement of the mechanical properties.The results show the increase in DMBA content or NCO:OH ratio may be used to decrease the particle size of aqueous polyurethane polyol, increase the Tg for two-component aqueous PU film and maybe adjust the mechanical properties of resulting film.

The polyimide foam (PIF) was prepared by the foaming of precursor derived from dimethyl ester of 3,3′,4,4′-biphenyltetracarboxylic dianhydride (BPDA) and 4,4′-diaminodiphenyl methane (MDA). The structure and properties of polymers were investigated by FTIR, 1H NMR, TG, DSC, SEM and mechanical testing. The findings show the PIF developed is of glass transition temperature of about 309°C, weight loss 5wt% at 517°C, density of 0.0018 g/cm3, cell structure of about 150μm, open-cell of 20%, thermal conductivity of 0.0277W/cm·K suitable for thermal insulation foam.

Screw conveyor is widely used in food packaging field. This paper puts forward a new kind of flexible blades of screw conveyor, to replace the traditional rigid helical blade. Based on the theory of compliant mechanism, the motion are analyzed when the flexible screw blade works. Based on the medium mechanics theory related, The interaction between flexible screw and material relations are analyzed, and the mathematical model of power consumption and transmission capacity are established. The work process of flexible screw working process is simulated with discrete element software EDEM. The result verified the theory is correct.

According to the cutting theory of involute tooth profile, established an exact three-dimensional parametric model by UG. Used ABAQUS to crate finite element model for gear meshing. After simulated the meshing process, discussed the periodicity of the tooth surface contact stress. Based on the result of finite element analysis, made a comparison of the maximum contact stress between finite element solution and Hertz theoretical solution, analyzed the contact stress distribution on tooth width, and researched the effect of friction factor on contact stress. All that provided some theoretical basis for gear contact strength design.

On-site metrology calibration is of practical significance and necessity to promote the rational development and utilization of water resources and to strengthen the management of water metering facilities specification. In this paper, on-site flowmeter calibration method and principle is detailed with standard instrument comparison test, deviation control range of on-site metrology calibration measurement is proposed with the application of error theory. Standard instrument reference method is proved to meet on-site metrology calibration requirements by examples analysis. Further research orientation is also put forward.

Teaching programming and manual programming are usually used to realize gait planning of humanoid robot. Many methods are lack of the adjustment of center of gravity and lead to the robot walking instability. The gait planning of humanoid robot is solved based on the Linear Inverted Pendulum Model and Zero Moment Point equation in this paper. Two feet trajectories are also planned to realize the smooth transition and overcome the impact during walking with the cubic spline interpolation method. The validation and feasibility of the method proposed in the paper are proved by the results of simulation and experiments.

The thermal degradation of phenolic formaldehyde resins (PF) were studied using thermo gravimetric analysis (TGA). The evolved volatiles during thermal degradation of PF were examined by mass spectrometry (MS). The structure changes of thermal degradation of synthetical phenolic resin (PF1.2) and commercial resin (CPF) were investigated by solid-state 13C nuclear magnetic resonance (13C-NMR) techniques. The experimental results show that the degradation process of PF could be separated into three stages. In the first stage, ether bonds and unreacted terminal hydroxymethyl groups of the cured resin degraded. Methylene bridges decomposed into methyl groups then yielded both phenol and cresol homolog in the second stage. In the third stage, cyclodehydration and forming char of phenolic hydroxyl occurred. Our study showed that the main thermal degradation of PF in the second stage is the decomposition reaction of the methylene bridges instead of auto-oxidation of the methylene bridges reported in previous works.

A high amplitude, fast rising time, and high isolating strength trigger signal is needed for triggering spark gap switch. A high voltage power supply scheme was verified by means of simulation in this paper. Proper parameters of power supply circuit were selected according to the simulation result. Finally, a pulsed power supply was developed. The experimental results show that a negative pulse with 25 kV isolating strength and 15 kV amplitude can be generated by the power supply, and this generated negative pulse can meet the demand of triggering spark gap switch.

Ozone is widely used in industry or even home nowadays, the power supply with frequency and duty cycle easy-adjust feature is very important to ozone production. An intelligent power supply based on MCU system is introduced in this paper, Intelligent Power Module (IPM) is used to compose a full bridge inverter circuit, and PWM technology is used to drive the IGBTs integrated in the IPM. The frequency and duty of the output AC can be adjusted manually or by auto tracking, and can be displayed synchronously on the LCD. The result shows that the power supply can adjust and display the output frequency and duty cycle by keyboard manually or by auto tracking based on detected current, and ozonizer have a higher efficiency with adjustable output frequency and duty cycle.

In the paper, the natural gas engine (NGE)model based on AVL BOOST software is built and simulated. The simulation value and experiment value coincide, showing that the NGE model is correct and reasonable. On this basis, the model has been used to analyze the effect of the key parameters, such as compression ratio, ignition advance angle, valve timing, supercharging ratio on the engine power, maximum combustion pressure, exhaust temperature, the maximum rise rate of pressure. Combined with the relevant theories of engine, the value ranges of the key parameters can be designed. The research achievement is valuable in the development and optimization matching of the NGE.

The image fusion algorithm discussed in this paper which utilizes wavelet decomposition and fuzzy reasoning combines images from diverse imaging sensors into a single composite image. It first decomposed source images through wavelet transform, computed the extent of each source image’s contribution through fuzzy reasoning using the area feature of source images, and then fused the coefficients through weighted averaging with the extents of each source images’ contributions as the weight coefficients. Experimental results indicate the final composite image may have more complete information content or better perceptual quality than any one of the source images.

When gear is working, the size of contact stress with tooth surface directly affects its service life and security. In this paper, creates a three-dimensional model of parametric gear by the UG parametric modeling tool, then transforms the modeling data and imports into ANSYS to analysis the loading-velocity of gear and the compressive stress produces through gear meshing. Finally, gets the distribution and the change rule of equivalent contact stress with tooth surface when produced radial displacement and in the case of several teeth contacted in gear running. Introduction

The article introduces the vibrating test of gear box in the engineroom of 1.25MW wind turbine in wind farm in Inner Mongolia province, and obtains the detailed structure form and parameters of the wind turbine, and has real-time monitoring on four wind turbines of four typical areas in the wind farm, and gets time domain response of wind turbine. The on-line condition monitoring was applied on full power test platform that uses 1.25MW wind turbine, vibrating test was used for key parts in the engineroom of wind turbine, spindle, gearbox, generator ,generator underframe and so on, and the natural frequency of generator underframe and time and frequency domain response of gearbox, ring gear, generator and generator underframe are obtained. Through two tests, the vibration characteristic in the engineroom is obtained.

In this paper, the Neimenggu high alumina coal gangue was calcined at 400℃~1000℃, its micro-structure in different calcining temperature was studied using XRD and IR, and then the preferred activated condition and the PAI were investigated by testing the strength of cement mortars with activated coal gangue. The result shows that: the optimal calcining temperature of the gangue is 800℃, at this temperature the high activated SiO2 and AI2O3 can be decomposed from the gangue. The activity of the original gangue is very high, the PAI of the cement mortars with 800℃ activated coal gangue can achieve to 126%, and thus can be used as high activity cement admixture. The PAI of the high alumina gangue is higher than that of coal gangue from other parts of China.

This paper discusses the establishment and improvement of the performance evaluation and supervision system of public investment projects in China, aiming at promoting the standardization, scientific and rationality of China’s public investment. We constructed a benign long-term mechanism which is deterrent to corrupt behavior in the field of public investment and also promotes economic growth, in order to improve the operational efficiency of public investment projects in China.

Based on the modeling and simulation software 20-sim developed by Control Engineering Group in University of Twebte in the Netherlands, the bond graph model of the hydraulic system for the working device of ZL50 wheel loader was established. During simulating the model, with the main parameters of the model were set based on the actual test result, which can skip deriving state function and simulate the system directly with the results of pressure response. The simulation results show that this method is feasible and convenience in the application of hydraulic dynamic simulation. Further more, through the test of cylinder pressure when the loader in the practical work, by comparing with the simulation results, which provides a new way in the field of dynamic modeling and simulation for hydraulic system.

This work aims at developing a new environmental-friendly treatment for hot-dip galvanized (HDG) steel as alternative to the classic systems based on chromates. A double layer film on the HDG steel sheets was prepared by immersing the sheets in 5 g/L Ce(NO3)3 aqueous solution and 5 vol.% silane solution in turn. The morphology of the cerium conversion film was analyzed using scanning electron microscopy (SEM). The corrosion resistance of the films was investigated by linear polarization (LPR) and natural salt spray (NSS) tests. The results show that the surface morphology of cerium conversion film appears on a “dry-mud” structure, which is favorable to enhance the combined strength between the cerium conversion and the silane film. The corrosion protection efficiency of the double layer films increases greatly, especially both the anodic and cathodic processes of zinc corrosion on the samples are suppressed conspicuously, and the synergistic protection effect of the single cerium film and the single silane film is evident.

In this paper, the conical spiral blade cutting model is analyzed and deduced, and the conical spiral blade cutting formula and blanking method is studied. The blank is processed with Archimedes spiral cutting method,and the forming spiral can be completed only with several processing. The new blanking method makes complex production process more simplified, save a lot of material, and the design method is more suitable for actual production. In the actual machining process the desired results are achieved.