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In this study, the plasma oxidation effect in tin-oxide (SnOx) thin film was investigated. And on this basis, we fabricated n-type thin-film transistors (TFTs) using the SnOx thin film with the plasma oxidation by experiments. By adjusting the processing time of the oxygen plasma treatment (OPT), the optimized SnOx TFT device exhibited an extremely high field-effect mobility of 87.6 cm2 V−1 s−1, a desirable on-to-off current ratio of 1.9 × 104 and a threshold voltage of − 0.9 V. Furthermore, we investigated the origin of the performance enhancements in the n-type SnOx TFTs with the optimized OPT by introducing the density of states (DOS) modeling in TCAD simulation. The numerical simulation indicated that the attributes of donor-like Gaussian defect states (oxygen vacancies) were modified in overall DOS due to the plasma oxidation effect. These present results show that the SnOx TFT treated by oxygen plasma has great promise in the future high-performance flat panel display industries.

Two-phase cooling technique including flow boiling heat transfer in microchannel is being widely applied in the mechanical and electronic devices, whereas most of the existing related studies still...

Factors affecting eutectic Si modification in Al-Si hypoeutectic alloy with the addition of Na, Sr, Eu and Yb were investigated. The modification effect is determined by element concentration in eutectic Si, which is mainly attributed to the solubility of modifying element M in α-Al and the interaction energy parameter of Al (or Si) and modifying element. A great modification is achieved by M of a limited solubility in α-Al and a moderate interaction energy parameter of Si (or Al) and M. The results are verified by the experimental results reported in the previous literatures. The effect of cooling rate on modification is also discussed in this work.

The smooth spherical BiOCl photocatalyst was synthesized successfully by a facile solvothermal method and further characterized by X-ray diffraction, scanning electron microscopy, energy dispersive spectrometer and UV-Vis diffuse reflectance spectra techniques. The photocatalytic activity of as-prepared photoctalyst was evaluated by the degradation of Rhodamine B (RhB) under visible light irradiation (λ>420 nm). The results showed that the BiOCl with smooth spherical morphology exhibits an excellent photocatalytic activity and stability. RhB was thoroughly degraded after 60 min of visible light irradiation.

AZ91D magnesium alloy substrate was first pretreated in a phosphoric acid to obtain a phosphate coating, and then, the electroless ternary Ni-W-P coating was deposited using a sulfate nickel bath. The morphologies of the Ni-W-P coating were observed by using scanning electron microscope, the deposition rate of the coating was examined with the method of gravimetric analysis, and the phase analysis was identified by x-ray diffractometer. Electrochemical property was tested by means of an electrochemical analyzer. The results indicated that the addition of an optimum concentration of CeO2 (cerium oxide) particles could evidently improve the deposition rate and the stability of the plating bath. However, it acted as an inhibiting effect as the concentration of CeO2 particles exceeded to 8 mg/L in the sulfate nickel bath. The results also revealed that the morphology of Ni-W-P coating became more smooth, compact and uniform with the increase in the concentrations of CeO2 particles in the bath, but the corrosion resistance decreased due to the precipitation of crystal phases (Ni3P, Ni4W, etc.) after heat treatment.

In this study, the superior effect of RbF on reducing the hydrogen desorption operating temperature of the Li N H system was demonstrated. By doping 5 mol% RbF in the LiNH2 LiH system, we obtain the lowest hydrogen desorption peak temperature (211 °C) at a heating rate of 5 °C/min, which is approximately 69 °C lower than that of the pristine LiNH2 LiH system. Moreover, the system starts to desorb H2 at 120 °C, which is the lowest hydrogen desorption onset temperature. The hydrogen desorption peak and onset temperatures can be further decreased by doping more RbF. It is proposed that the RbH produced during heat treatment improves the dehydrogenation properties of the RbF-doped LiNH2 LiH sample.

Long rod has strong ability of penetrating into targets with high velocity because of the big ratio of L/D. In the process of the penetration, the resistance of target is so big that the deformation of the head of the projectile is severe. There are many factors influence the process, which make it difficult to get analytic solutions. In this paper, we propose a simplified calculation method which considering engineering strain of the head of projectile. And the rigid-plastic model was used to describe the constitutive model of projectiles. The relationship between the engineering strain of the mushroom area and velocity was analyzed, which is exponential. Then, combined with cavity expansion theory, the calculation results about the DOP are in good agreements with the experimental results. At last, there are numerical simulations about the relative experiments, and the results obtained from numerical simulations show the deformation of the projectile and the depth of the penetration, which are in good agreement with the theoretical calculation and experiments.

The goal of this research is to investigate cratered hole geometries on film cooling performance. Five kinds of cratered holes, namely, the concentric crater, the circular crater, the downstream offset crater, the upstream offset crater, and the direct crater are being studied along with the conventional flush hole. All craters has the same depth of 0.5 hole diameter. Through numerical simulation with CFX at a single blowing ratio of 0.5 and Reynold number of 11000, we analyze and compare the performance and behavior of five kinds of cratered holes with the conventional cylindrical hole. The simulation employs k-ε turbulent model and wall function. Film cooling effectiveness is achieved for all cases. Among all cases, concentric cratered hole perform the best which increases averaged film cooling effectiveness by 64% at X/D=5.35. All cratered holes appear some performance improvement compared to the baseline case. For cratered holes, film lateral convergence and stream-wise attaching performance was both enhanced owing to the expansional configuration of the crater and the consequent backflow region.

The effects of pre-treatments on the precipitate microstructures of an Al-Zn-Mg-Cu alloy are investigated. Meanwhile, the creep-rupture behavior of the under-aged and peak-aged alloys are comparatively analyzed. Additionally, the effects of pre-treatment on the fracture mechanisms are discussed. It is found that the precipitate microstructures are sensitive to pre-treatments. The intragranular precipitates of the peak-aged alloy are larger than those of the under-aged. The precipitate free zone of the peak-aged alloy is wider than that of the under-aged. Some large intergranular precipitates appear on the grain boundaries of the under-aged alloy, and induce the nucleation of microvoids. Eventually, the creep fracture of the under-aged alloy is accelerated. Therefore, the differences in microstructures lead to the shorter creep-rupture life of the under-aged alloy, compared to the peak-aged alloy.

Passively compensating a payload weight requires a mechanism that can generate a nonlinear torque curve. Existing gravity-balancing mechanisms (GBMs) rely on linear or torsional springs with various principles to generate the required torque profile. This paper presents the design of a novel GBM whose balancing capability can be adjusted. The idea is to employ two linear springs, one extension spring and one compression spring, to synthesize the required nonlinear torque curve. The springs are concentrated on the base joint to reduce the overall size. An optimization formulation is given to maximize the weight compensation capability. The effects of various parameters on the achievable weight are discussed. Low-volume planar springs are specifically designed to serve as the linear springs so that large stiffness can be generated in a limited space. By preloading the springs, the GBM can easily adjust its torque curve to match different payloads. An illustrative prototype is given with experiment verifications to demonstrate the claimed merits of the proposed GBM.

In this study, we sought to control the assembly of an endotoxin known as the biologically supramolecular lipopolysaccharide (LPS, which consists of three portions: an O antigen, a core carbohydrate, and a lipid A molecule) in order to modulate immunological responses in a manner that has the potential for utilization in vaccine development. Changing the structures of LPS aggregates from lamellas to specific nonlamellas (i.e., cubosomes and hexosomes) can dramatically enhance the strength of LPS in causing inflammatory responses, leading to highly active responses. In order to control the formation of cubosome-free and hexosome-free nonlamellas, we designed a simple strategy based on the use of hydrophilic gold nanodots (AuNDs) to control LPS assembly to facilitate the formation of stable endotoxin nanovesicles, which are stable precursors of cubosomes and hexosomes with specific immunological effects. Structurally, the wall thicknesses of these nanovesicles are exactly twice the lengths of a single LPS molecule, indicating that the LPS molecules adopt a tail-to-tail arrangement (with the lipid A portions acting as the tail domain). The involvement of the hydrophilic AuNDs to laterally link polar domains of LPS can result in the progressive extension of an endotoxically active zone of lipid A assembly, leading to the eventual formation of large-size nanovesicles. Our results showed that endotoxin nanovesicles with such dense lipid A units can elicit the stronger inflammatory gene expressions, including interleukin 6 (IL-6), IL-1A, TNF-α, C-X-C chemokine ligand (CXCL) 1, 2, and 11, which have characteristics of T-helper 1 adjuvants. These findings provide evidence that the concept of manipulating the surface hydrophilicity of AuNDs to control LPS assembly in order to avoid the formation of highly active cubosomes and hexosomes, and thereby modulate immunological responses appropriately, could prove useful in vaccine development.

Alumina ceramics film which has high hardness, wear resistance and erosion resistance can be obtained using micro arc oxidation on the surface of aluminum alloy. The process parameters have great influence on the surface morphology of alumina ceramics film prepared by micro arc oxidation. In this research, the alumina ceramics film was gotten using micro arc oxidation with different process parameters. The surface morphology of ceramics film was analyzed using scanning electron microscope (SEM). The SEM photograph was processed using ImageJ software. The dimensions of holes diameter and porosity on the surface of ceramics film were investigated. The influence regularity of process parameters such as current density, impulse frequency, duty ratio and process time to the surface morphology of alumina ceramics film was researched. This can provide basis for the optimization of process parameters.

Alumina ceramics film which has high hardness, wear resistance and erosion resistance can be obtained using micro arc oxidation on the surface of aluminum alloy. The process parameters have great influence on the corrosion resistance of alumina ceramics film prepared by micro arc oxidation. In this research, the alumina ceramics film was gotten using micro arc oxidation with different process parameters. The corrosion resistance of ceramics coating prepared by micro arc oxidation on the surface of aluminum alloy was investigated by putting the samples into sodium chloride solution of the concentration 3.5%.The influence regularity of process parameters such as current density, impulse frequency, duty ratio and process time on the corrosion resistance of alumina ceramics film was researched. This can provide basis for the optimization of process parameters.

The effects of various input parameters on the warpage of strip were investigated and discussed. Three theoretical techniques, including virtual layers method (VLM), energy balance method (EBM), and finite element method (FEM), were adopted to evaluate the distributions of plastic strain, temperature, and stress of the strip, respectively. The longitudinal residual warpage can then be calculated accordingly. It was found that the cooling condition in cooling section plays a key role on the residual warpage of strip, which is possibly to be controlled within an accepted range by applying a suitable cooling scheme in this section.

Digital watermarking is an encryption technology commonly used to protect intellectual property and copyright. In this study, we restored watermarks that had already been affected by noise interference, used the Walsh–Hadamard codes as the watermark identification codes, and applied salt-and-pepper noise and Gaussian noise to destroy watermarks. First method, we used a low-pass filter and median filter to remove noise interferences. The second one, we used a back-propagation neural network algorithm to suppress noises. We removed nearly all noise and recovered the originally embedded watermarks of Walsh–Hadmard codes.

Because the process of blade in electrochemical machining(EMC) can be effected by many factors, such as blade shapes, machining electrical field, electrolyte fluid field and anode electrochemical dissolution, different ECM machining parameters maybe result in great affections on blade machining accuracy. Regard some type of aero-engine blade as research object, a great deal of ECM machining parameter combination which probably result in machining failure can be eliminated based on BP neural network firstly. Furthermore, the optimized ECM machining parameter combination has been discovered. To verify the validity of the optimized ECM parameter combination, a serial of machining experiments have been conducted on an industrial scale ECM machine, and the experiment results demonstrates that the optimized ECM parameter combination not only can satisfy the manufacturing requirements of blade fully but has excellent ECM process stability.

Electrochemical micro-machining (EMM) has become one of the main machining methods for production of miniaturized parts and components. Utilizing the developed EMM set-up, the effects of ultrasonic wave frequency on characteristics of localized dissolution and accuracy of micro-hole in EMM are investigated and evaluated. The experiment results demonstrate that the accuracy of micro-hole and characteristics of localized dissolution can become better with the increase of ultrasonic wave frequency. The accuracy of micro-hole machined by 26KHZ can improve about 30% than that by 16KHZ. Moreover, the ability of localized dissolution by 26KHZ can be increased about 27%-30%.

We propose a novel non-parametric method to identify generalized frequency response functions (GFRFs) for multi-input multi-output (MIMO) nonlinear systems in this paper. Firstly, the formula to calculate GFRFs is derived in terms of the corresponding output frequency properties of GFRFs of the MIMO nonlinear system excited by a single-tone signal. Secondly, to improve the efficiency of the non-parametric identification method, we utilize the multitone excitation to drive the MIMO nonlinear system, and propose a searching algorithm of the frequency base of multitone excitation. Finally, the general procedure of identifying GFRFs of MIMO nonlinear system excited by the multitone excitation is summarized. The proposed non-parametric identification method is suitable for application as it only depends on input–output data of the MIMO nonlinear system and avoids time-consuming study of its complicated physical mechanisms. Moreover, the proposed non-parametric identification method is proved to be effective by the precisely identifying GFRFs of a two-input two-output nonlinear system.

Accelerating axle gear-shift hole processing technique of CNC equipment headstock was improved for gear colliding with housing wall during processing, interference phenomenon, galling and surface quality during scrapping plane. Experience proves that the machining process improvement of the accelerating shaft shift holes of the headstock is very successful and the product bottleneck effect is eliminated.

The short carbon fiber (Cf) reinforced hydroxyapatite (HA) bio-composite was prepared by an in-situ processing. Mechanical properties and microstructure of Cf/HA were investigated. Structures of HA was analyzed using XRD and fracture surface morphologies of bio-composite were analyzed using SEM. Result shows that grain size of HA under hot pressing sintering (1423K, 35MPa) grow up to approximately 50nm. Bio-composite exhibits excellent mechanical properties when Cfmass fraction is 3%, whose flexural strength and flexural modulus reach the maximum values of 130MPa and 36GPa which surpass common level of nature bone. SEM fracture surface morphologies of Cf/HA shows Cfcan be uniformly dispersed in the HA matrix when the mass fraction less than 6%, while when the mass fraction is11%, partial aggregation appears.

A new kind of ultrasonic machining is proposed for sintered NdFeB permanent magnet. Experiments were carried out on self-made equipment. Test results showed that the MRR would increase with the amplitude of tool, static load and the size of abrasive grain at certain range. This kind of ultrasonic machining is a suitable method for machining NdFeB material.

Electrochemical micro-machining (EMM) appears to be very promising as a future micro-machining technique, since in many areas of applications, it offers many advantages, which include excellent machining precision and control, high machining rate, perfect surface quality and a wide range of materials that can be machined, regardless of their strength and toughness. In the paper, a new style EMM equipment for micro-holes is presented. Double vertical column style structure is chosen as the main mechanical structure of the equipment, which has the advantage of excellent structure rigidity, compact framework dimension as well as good maneuverability and maintainability. In order to verify the reliability of this EMM equipment, some measurement works including static measurements, assembling interferences checking and kinematics simulation have been done. Furthermore, the low-speed kinematics characteristics of the developed EMM equipment are concentrated. The kinematics simulation results indicate that the developed EMM equipment can satisfy the requirements for low-speed motion and anti-interference characteristics of EMM process.

Because the process of blade in electrochemical machining(EMC) can be effected by many factors, such as blade shapes, machining electrical field, electrolyte fluid field and anode electrochemical dissolution, different ECM machining parameters maybe result in great affections on blade machining accuracy. Regard some type of aero-engine blade as research object, five main machining parameters, applied voltage, initial machining gap, cathode feed rate, electrolyte temperature and pressure difference between electrolyte inlet and outlet, have been evaluated and optimized based on BP neural network technique. From 3125 possible machining parameter combinations, 657 optimized parameter combinations are discovered. Furthermore, the final optimized ECM process parameters have been obtained. To verify the validity of the optimized ECM parameter combination, a serial of machining experiments have been conducted on an industrial scale ECM machine, and the experiment results demonstrates that the optimized ECM parameter combination not only can satisfy the manufacturing requirements of blade fully but has excellent ECM process stability.

Electrochemical micro-machining (EMM) has become one of the main machining methods for production of miniaturized parts and components. Utilizing a developed EMM set-up, sets of experiments have been carried out to investigate the influences of some of the predominant electrochemical process parameters such as pulse frequency, feed rate of tool, machining voltage and ultrasonic frequency on the machining accuracy of micro-holes. According to the present investigation, the most effective zone of pulse on time and ultrasonic frequency can be considered as 15-50μs and 26KHZ, respectively, which can gives a desirable machining accuracy for micro-holes. A machining voltage range of 6-10V can be commended to obtain high machining accuracy. From the micrographs of the machined micro-holes, it may be observed that a lower value of electrolyte concentration with moderate machining voltage and moderate value of pulse on time will produce more accurate shape of micro-holes.

The energy transfer method is used to measure the flow velocity of the outside the high pressure water jet (WJ) and Abrasive water jet (AWJ) nozzle. The impact forces of the flow measured by the piezoelectricity ergometer will be transformed to the velocity value, the average velocity of the flow outside the nozzle will be obtained. The result indicates the velocity will reduce along the direction of the flow, and the velocity of the AWJ flow will reduced greatly than the WJ flow, which indicates that the length of the core part of the AWJ flow is shorter than the WJ Flow, the stand-off should be within the 0mm-15mm ranges to gain the most effective machining.

Laser cladding is a new developed green manufacturing process. The main process parameters include the power of laser beam, the diameter of laser facula, the scan speed and the quantity of powder supply. It’s difficulty to analyse the influence of the process factors to the product quality because the effect mechanism is quiet complicated. Model of Artificial neural network for the optimization of process parameter in laser cladding manufacturing was developed in this paper. And proper process parameters were achieved which can provide guide for the practice production.

Sintered NdFeB permanent magnet is widely used in many areas because of its excellent magnet property. In this study, the machining parameters of electrical discharge machining (EDM) are varied to study the effects of electrical discharge energy on material removal rate and surface roughness of NdFeB magnet. Moreover, the micro-cracks on the machined surface induced by EDM are also examined. The experimental results reveal that the MRR increases with the electrical discharge energy. The number of surface cracks on the machined surface increases with the enhancement of discharge energy Thus, using EDM process to machine sintered NdFeB magnet depends on setting the machining parameters to prevent surface crack.

Sintered NdFeB magnet is widely used in many areas because of its excellent magnet. This paper studies the effect of ultrasonic vibration of tool on electrical discharge machining of it. Experiments were carried out on self-made equipment and material removal rate(MRR) against pulse-on time, MRR versus peak current and machined surface results with and without ultrasonic employment were analyzed. Results show that MRR of the ultrasonic assisted electro-discharge machining would be up to five times higher than MRR of the conventional EDM for small pulse durations and low discharge currents. The machined surface of US/EDM is finer than EDM because of less arcing and short circuit pulses. There are less cracks on the surface.

A simulation system was developed to forecast machining quality and optimize grinding parameters for the machining of ceramic die material. The system can forecast the surface quality of machined ceramic die material with high precision, optimize machining parameters and analyze the dominant factors. Based on the process database, the simulation system is applicable to various machining methods. It can help to raise the automaticity for the machining of ceramic die material and develop the farther intelligent system.

This study aims to experimentally explore the thermal histories and temperature distributions in a workpiece during a friction stir welding (FSW) process involving the butt joining of aluminum 6061-T6. Different types of thermocouple layout are devised to measure the temperature histories during FSW at different locations on the workpiece in the welding direction. Successful welding processes are achieved by appropriately controlling the maximum temperatures during the welding process. Regression analyses by the least squares method are used to predict the temperatures at the joint line. A second-order polynomial curve is found to best fit the experimental temperature values in the width direction of the workpiece. The Vickers hardness test is conducted on the welds to evaluate the hardness distribution in the thermal-mechanical affected zone, the heat affected zone, and the base metal zone. Tensile tests are also carried out, and the tensile strength of the welded product is compared with that of the base metal.

Based on the basic geological features of Yixingzhai gold deposit, the geological features, classification and relation to mineralization of breccia pipes were discussed by surveying the xenoliths and breccia’s mineral composition, structure and construction, typical mineralization alteration phenomenon on field and microscopic anatomy in breccia pipes. And the ore-controlling mechanism and the formation mechanism of the blasting breccia pipes were investigated. The main conclusion shows that Hewan and Nanmenshan breccia pipes nearby the NW-striking deep fault are shaped earlier, belonging to the acidic siliceous ingredient production of ultra-hypabyssal magmatic in the late magma stage; Tietangdong and Nanmenshan breccia pipes that are shaped latter are the ultra-hypabyssal auriferous fluid production composed mainly of the skarn in the hydrothermal stage after the magma period. Both root in the unified deep magmatic chamber, belonging to differentiation derivatives at different stages in the deep magmatic chamber.

Simulation of the flow field of the gas-liquid-solid three-phase flow outside the abrasive water jet rectangle nozzle and ellipse nozzle is studied by the computed fluid dynamic software-fluent, and the velocity field of the three-phase flow is obtained. The simulation result expresses that the flow is expanded when it is out of the nozzle; the velocity of the flow is the highest at the axis, which comes down by its side, the velocity of the flow is high at the beginning then it is decreased because the flow is resisted by the air; the shape of the jet at the start is closed to the geometry of the nozzle, then it is rounded in the external area; the velocity field outside the ellipse nozzle is distributed evenly around the center. By plotting the velocity field of the rectangle nozzle and the ellipse nozzle in the Y-Z section, it is expressed that the changing range of velocity is enlarged with the increasing of distance offset the nozzle.

A new kind of ultrasonic machining method named ultrasonic machining aided tool rotation is proposed for sintered NdFeB permanent magnet. In the process abrasive slurry enters the machining area through holes in the rotary tool which can assure the grains easily enter the machining surface slurry. Its machining mechanisms are studied and material removal model is developed. Experimental research was carried out on self-made equipment. Experimental results were accordance with the developed model. It is proved that this new kind of ultrasonic machining technology is suitable to machine deep hole for sintered NdFeB material.

For applying acoustic radiation force to manipulate biomaterials such as cell, DNA, bio-macromolecule without contact, stationary sound field of an ultrasonic transducer was computed numerically. With the numerical data about the sound field, spatial distribution of the acoustic radiation force was analyzed. Besides the radiation force in the axial direction, trapping forces in the lateral direction were discovered. By moving the reflector continuously and carefully, positions of trapping wells were changed simultaneously, as the result, non-contact manipulation of micro cells was implemented.

Sintered NdFeB permanent magnet is widely used in many applications because of its excellent magnet property. However the report of EDM research on NdFeB magnet is not available. This paper presents a detailed investigation of the material removal mechanisms of sintered NdFeB magnet through analysis of the machining debris and the surface SEM quality. It is included three types of machining mechanisms: melting and evaporating, thermal cracking, spalling or whole grain removal.

Effect of whisker orientation on mechanical properties of hydroxyapatite-SiCw composite bioceramics was studied in this paper. Experiment results show that the mechanical properties of the material are the best when the tensile stress acted on the composite material is parallel with the hot pressing plane or the shearing stress is normal to the hot pressing plane, and they are the worst when the tensile stress acted on the composite material is normal to the hot pressing plane or the shearing stress is parallel with the hot pressing plane. This will offer great guidance for practical applications of the hydroxyapatite-SiCw composite bioceramics.

A porous composite scaffold for tissue engineering had been developed through a novel gel-casting approach with needle-like nano hydroxyapatite (HA) crystallites and chitin. The freeze-dried nano-HA powder was firstly dispersed in the chitin solvent before chitin dissolves in its solvent completely. The composite solution was evenly mixed with a selected porosifier and poured into a mold in which it became a composite gel under the reaction of water molecules in atmosphere. Subsequently, the composite gel was subjected to the simultaneous extraction of the porosifier and chitin solvent in distilled water. After the drying process the porous composite scaffold was obtained. The morphological analysis showed that the manufactured scaffold had uniform and isotropic porous structure with controlled, fully interconnected pores. In vitro experiments indicated that the bone-like apatite layer formed easily on the walls of the porous n-HA/chitin composite scaffold.

The material removal mechanism of ultrasonic machining sintered Nd-Fe-B magnetic materials was studied theoretically. The relation between critical load and central crack is given. In order to assure the material removal mode on material surface is brittle micro-fracture, the acting force of a single abrasive particle working on workpiece surface should be higher than the critical load. Experimental results show that there should be an optimal static load and an optimal abrasive size in certain ultrasonic machining system. The research results are helpful to guide practical production.

Theory calculation result indicates that the maximal critical content of SiCw in hydroxyapatite-SiCw composite bioceramics is 23.7%. Hydroxyapatite-SiCw composite micropowder was synthesized using in-situ composite method, and hydroxyapatite-SiCw composite bioceramics with different content of SiCw were produced by hot pressing sintering method. The microstructures of the materials were analyzed by SEM, and the mechanical properties were tested. The results show that the mechanical properties of composite material are the best when the whisker content is 20~23.7%.

In the internal air system of modern aero-engine, the cooling air is generally taken from the compressor platform, transported radially inwards towards the shaft and further transported to the hot parts. Since strongly swirling air is bled in the compressor rotor to a much lower radius, a means of vortices will be created, which lead to very high pressure losses and limit the cooling flow rate. The present work investigates the fluid flow for twelve kinds of vortex reducer geometries which utilize columnar baffles to divide the cavity into several chambers and avoid extensive vortex formation, therefore the pressure loss decreases and the flow mass increases observably. Based on the numerical study, the pressure loss is closely related to the curvature of the curve and the intersection angle (β) at the entry. Geometries of columnar baffles installed in the cavity include the straight angled degrees (0°,45°,60°) towards the radial and the curved such as Archimedean spirals (ρ = aθ, a = 12,20,30), hyperbolic spirals (ρ θ = a, a = 50,80,100) and logarithmic spirals (ρ = eα θ, α = 0.3,0.4,0.5). For the straight, the attention is focused on six and twelve baffles which are evenly arranged along the circumferential, but six ones for the curved. Otherwise, a key point is that the total volume of baffles is equal for different vortex reducer geometries. The results show that vortex reducer configurations with twelve baffles perform better than those with six baffles for the straight with the same angle. Compared with the straight radial baffle, the other kinds of baffles play better roles with respect to reducing pressure losses and gaining large flow mass. As a rule, the large pressure loss occurs when the curvature for the curved is large, because the flow direction changes greatly. A dedicated investigation about the influence of varied vortex reducer configurations is presented in this paper, particular discussions and conclusions are shown.

Based on the static strength calculation, the fracture reason was examined for the last stage moving blades of an Extraction Condensing Steam Turbine (ECST) in a power plant. The calculations revealed that the original blade design was unreasonable, which resulted in the compound stress exceeding the material allowable stress. The study was focused on redesigning the broken moving blade by means of three-dimensional design on the premise of satisfying the static strength requirement. Furthermore, by using commercial CFD (Computational Fluid Dynamics) software NUMECA, the flow field was simulated and analyzed for both the last stage and the penultimate stage under the circumstances of unbroken and broken, so was it for the redesigned last stage. Detailed discussion was given to the influence of the broken blades on the performance of the whole stage, and feasible conclusions were drawn on the improved moving blades. It was shown that the redesigned moving blades produced a good performance under practical operation.

The rigid-elastic coupling model of air suspension and the virtual prototype model of the commercial heavy-duty truck are established by means of finite element and multi-body dynamic methods. The virtual prototype model of the truck is validated by experiment and simulation analysis of a pulse excitation response. A digital Belgian block road is modelled based on measured data from a proving ground. Stress-time history of the shoulder pole beam is calculated when the virtual prototype is run on the road. Fatigue analysis of the shoulder pole beam is completed by rainflow counting method and Miner's linear fatigue cumulation damage theory.

As a main difficult problem encountered in electrochemical machining (ECM), the cathode design is tackled, at present, with various numerical analysis methods such as finite difference, finite element and boundary element methods. Among them, the finite element method presents more flexibility to deal with the irregularly shaped workpieces. However, it is very difficult to ensure the convergence of finite element numerical approach. This paper proposes an accurate model and a finite element numerical approach of cathode design based on the potential distribution in inter-electrode gap. In order to ensure the convergence of finite element numerical approach and increase the accuracy in cathode design, the cathode shape should be iterated to eliminate the design errors in computational process. Several experiments are conducted to verify the machining accuracy of the designed cathode. The experimental results have proven perfect convergence and good computing accuracy of the proposed finite element numerical approach by the high surface quality and dimensional accuracy of the machined blades.