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Using laser welding-brazing technique to join 5A06 Al alloy and ST04Z galvanized steel, the authors study the effect of adding pure powder (Si, Mg, Mn, or Zn) in the joining on the material behavior of welded joints. The results show that the microstructures, tensile behavior, and corrosion behavior of the welded joints are dependent on the powder used in the welding. An intermetallic compound (IMC) layer consisting of Fe2Al5 and FeAl3 is formed between the Al alloy and the steel, which is independent of the pure element powder used. The IMC layer with the use of Zn powder has the least thickness. The welded joints with the use of pure Mg element powder have the largest corrosion resistance.Using laser welding-brazing technique to join 5A06 Al alloy and ST04Z galvanized steel, the authors study the effect of adding pure powder (Si, Mg, Mn, or Zn) in the joining on the material behavior of welded joints. The results show that the microstructures, tensile behavior, and corrosion behavior of the welded joints are dependent on the powder used in the welding. An intermetallic compound (IMC) layer consisting of Fe2Al5 and FeAl3 is formed between the Al alloy and the steel, which is independent of the pure element powder used. The IMC layer with the use of Zn powder has the least thickness. The welded joints with the use of pure Mg element powder have the largest corrosion resistance.

Using a laser welding method, the bulk metallic glass of Zr44Ti11Ni10Cu10Be25 is jointed to 1100 aluminum plate. There are two interfaces formed in the joint; one is the interface between fusion zone and aluminum, and the other is the interface between fusion zone and bulk metallic glass. The microstructures and chemical compositions of the joint are analyzed using scanning electron microscopy, energy dispersive spectrometer, and x-ray diffraction. There are island-like Zr–Al intermetallic compounds formed near the interface between the fusion zone and the bulk metallic glass, polygon-like and flower-like crystals formed in heat-affected zone, and Zr-rich phase formed in fusion zone. The laser welding leads to the formation of a composite-like structure consisting of crystals and amorphous materials. The Vickers hardness of the joint is measured. The material near the interface between fusion zone and aluminum has the largest Vickers hardness.

Based on the features of double electrode gas metal arc welding (DE-GMAW), a new hybrid heat-source model for DE-GMAW was proposed. Using this heat-source model, the temperature fields of DE-GMAW with different welding parameters were simulated. According to the simulation results with different welding parameters, the influence of welding parameters to the heat input to base metal in DE-GMAW were analyzed. To verify the rationality of the hybrid heat-source model of DE-GMAW, the simulation results of the temperature field were compared with the experimental results with same welding parameters. The research results indicate that under the same total current, the heat input to base metal decrease gradually with the increase of by-pass current. In addition, the closer to the welding line from the measured point the greater decrease rate of the heat input to base metal. By the study and comparison of the thermal cycle curve of measured points, the simulation results were in good agreement with the experimental results. These results indicate that the calculated temperature field is accurate and the hybrid heat-source model is rational.

To compare the experimental murine immunodeficiency models induced by cyclophosphamide (CP) and hydrocortisone (HY), and choose suitable animal models for function evaluation of health food.7 trials were performed: evaluation of spleen and thymus index and WBC count, evaluation of the phagocytic function of the reticuloendothelial system, evaluation of macrophage phagocytosis function, splenic natural killer (NK) activity, delayed type of hypersensitivity response, plaque-forming cell assay and assay of serum hemolysin to SRBC. The animals were randomly divided into 2 groups of 12 mice for each experimental series. Group 1 served as vehicle control and Group 2 served as the CP/HY treated control. CP-1 at 80 mg/kg was administered intraperitoneally on dayl, 2, 3, 9, 16, and 23. CP-2 at 50 mg/kg was administered intraperitoneally on dayl, 3, 5, 7, and 9. CP-3 at 40mg/kg was administered intraperitoneally on day 1 and 2. HY injection at 40 mg/kg was administered intramuscularly on day 1, 3, 5, 7, and 9. All groups were used for different immunomodulatory activity screening experiments, respect on day 29, 11, 7, and 10.Compared to vehicle control, the plaque-forming cells, serum hemolysin and WBC count were reduced in all CP groups. While the phagocytic function of the reticuloendothelial system, macrophage phagocytosis function, NK activity, delayed type of hypersensitivity response and WBC count were reduced in HY group.Both CP or HY could build a murine immunodeficiency model and they have different sensitivity indexes.

The technique of “crystallite growth preferred orientation” was presented based on the Monte Carlo (MC) simulations of grain growth, and its factor was used to establish a lattice coordinate tracking method. The nucleation and growth of crystal from the liquid phase throughout the whole simulation were examined. Changes in solid fraction and crystallite size were counted via simulation by lattice tracking. Results showed that the established model could properly reflect crystallite nucleation and growth. The model was also determined capable of accurately estimating the number of solid phase fraction and achieving change in crystallite size by the lattice tracking method. The change in solid fraction and MC step (MCS) satisfied the [Formula: see text] curve during simulation. The crystallite growth index was 0.477, which was relatively close to the theoretical value of 0.5.

Consumable DE-GMAW is a novel GMAW process with higher greater productivity. However, the consumable DE-GMAW process can hardly maintain stable without a proper control. Aiming at this problem, a rapid prototyping control platform was established for consumable DE-GMAW with a designed fuzzy controller using real-time target environment based on xPC. The developed experimental system makes it possible to sense, observe and control the consumable DE-GMAW process real-timely. On this basis, experiments were carried out to verify the feasibility of the fuzzy control system. The results show that good welding bead shape and stable welding process can be obtained through the developed fuzzy control system in consumable DE-GMAW process. This fuzzy control system lays a foundation for the consumable DE-GMAW process to become a practical manufacturing process.

Aimed at the problem of detection of pool edge for aluminum alloy MIG welding, a new method is adopted. The method is used to detect the pool edge of aluminum alloy MIG welding by applying the pulse coupled neural networks algorithm. The pulse coupled neural networks algorithm is introduced in this paper. The detection of pool edge for MIG welding pool is carried out with this algorithm by MATLAB. Then, the comparison between the result of PCNN algorithm and Canny detector is completed. The result indicates that the pulse coupled neural networks algorithm can be used to detect the process image of welding pool. And the image of pool edge by using the pulse coupled neural networks algorithm is clear and consistent. Besides, this new method can effectively overcome the influence of noise from welding pool image. The time of single frame processing is 54 ms.

Research work of wire extension control with Dual freedom PID controller in pulsed MIG welding process of aluminum alloy. In the condition of optimum parameters, the simulations were firstly completed by separately using Routine PID control and Dual freedom PID control, based on designing the wire speed of wire extension step response and gaining identification model. Based on the results of simulation using Matlab/Simulink, the experimental research on aluminum alloy pulsed MIG welding by using Dual freedom PID control was carried out in the real-time target environment with XPC Target. In the pulsed MIG welding process of aluminum alloy, the results prove that the Dual freedom PID control can bring higher precision and quicker response speed, efficiently control the stability of wire extension, and satisfy the stability of welding process.

Research work of wire extension control based on vision sensing was done in pulsed MIG welding process of aluminum alloy. In order to resolve the actuality problem of traditional PID control, a self-tuning fuzzy PID controller was designed and a rapid prototyping control platform was established for pulsed MIG welding of aluminum alloy using real-time target environment based on xPC. With vision sensing of welding zone image and corresponding image processing algorithm, a fuzzy PID closed loop control system for wire extension was designed on the basis of the built rapid prototyping control platform. Experimental results show that the method of vision sensing can meet the control requirements of wire extension stability, the rapid prototyping control system built with fuzzy PID controller based on vision sensing can realize well the control of the wire extension in pulsed MIG welding of aluminum alloy and also has strong robustness and quick response ability.

Aiming at the instability of dynamic welding arc and strong coupling among welding parameters, a mathematical model for consumable double-electrode gas metal arc welding (DE-GMAW) was established by the method of equivalent path and then dynamical analysis was carried out. On this basis, an approach was proposed to control the stability of the welding arc using the wire extensions of main and bypass torch as a control object. And then a comparative analysis of two different decoupling control schemes was made respectively using the bypass wire feed speed and the bypass current as input and using the wire feed speed of main and bypass as input. The results show that the mathematical model can reflect the process of consumable DE-GMAW well and the decoupling control scheme using the wire feed speed of main and bypass as inputs has better dynamic performance and robustness.

Based on system identification of pulsed MIG welding process for aluminum alloy, due to strong coupling among the welding parameters, PID controller, fuzzy PID controller and neural network inverse controller were designed, the strong coupling multi-input and multi-output (MIMO) system was simulated using pulse current duty cycle and wire feed speed as control input, and wire extension and pool width as control output. The results show that the neural network inverse control provides faster response and better robustness, which lays a foundation for decoupling control of aluminum pulsed MIG welding.

According to the stability problem of wire extension in aluminum alloy pulsed MIG welding, a rapid prototyping control platform using the xPC real-time target environment based on the sliding mode control theory was established, and then the real-time control on wire extension in aluminum alloy pulsed MIG welding was carry out with sliding mode controller. The results show that the sliding mode controller can control the wire extension accurately in aluminum alloy pulsed MIG welding and the rapid sliding model prototyping system has strong robustness on external disturbance and system parameters perturbation.

A new efficient welding method, Consumable DE-GMAW was proposed. According to the many problems occurred when the welding process is open-loop, such as instability of the welding process and a large welding spatter, etc. A real-time target hardware platform was built for consumable DE-GMAW based on xPC, and a rapid prototyping control system was also developed for consumable DE-GMAW with the Matlab/Simulink. The high-speed welding based on consumable DE-GMAW was realized under close loop control, and good weld shaping was acquired at high welding speed. Then the reasons realized high-speed welding through consumable DE-GMAW was analyzed briefly according to humping weld induced by arc pressure theory. The theory analysis and experiments results show that consumable DE-GMAW provides a new method for high-speed welding.

Single-crystal Ni2MnGa shows a nearly 0.2% strain under a magnetic field of 8 kOe at −8 °C. Polycrystalline samples have been prepared near stoichiometry to study the composition dependence of the magnetic and elastic properties. A narrow band of compositions has been found having a range of Curie and martensitic transformation temperatures, Tc and T0, extending to above room temperature. The compressive stress–strain characteristics in variable transverse field were studied in samples selected to have T0 just below room temperature. Stress-induced martensite was observed as expected and the magnetic field was applied under fixed load for various stresses. A transverse field of 3200 Oe caused the sample to strain under load doing work that increased up to 1.3 J/kg with increasing volume fraction of stress-induced martensite.

Single-crystal Ni2MnGa shows a nearly 0.2% strain under a magnetic field of 8 kOe at 28 °C. Polycrystalline samples have been prepared near stoichiometry to study the composition dependence of the magnetic and elastic properties. A narrow band of compositions has been found having a range of Curie and martensitic transformation temperatures, Tc and T0 , extending to above room temperature. The compressive stress–strain characteristics in variable transverse field were studied in samples selected to have T0 just below room temperature. Stress-induced martensite was observed as expected and the magnetic field was applied under fixed load for various stresses. A transverse field of 3200 Oe caused the sample to strain under load doing work that increased up to 1.3 J/kg with increasing volume fraction of stress-induced martensite. © 1998 American Institute of Physics. @S0021-8979~98!41211-8#

A three-dimensional model containing tungsten electrodes, arc plasma and a weld pool is presented for double electrodes tungsten inert gas welding. The model is validated by available experimental data. The distributions of temperature, velocity and pressure of the coupled arc plasma are investigated. The current density, heat flux and shear stress over the weld pool are highlighted. The weld pool dynamic is described by taking into account buoyance, Lorentz force, surface tension and plasma drag force. The turbulent effect in the weld pool is also considered. It is found that the temperature and velocity distributions of the coupled arc are not rotationally symmetrical. A similar property is also shown by the arc pressure, current density and heat flux at the anode surface. The surface tension gradient is much larger than the plasma drag force and dominates the convective pattern in the weld pool, thus determining the weld penetration. The anodic heat flux and plasma drag force, as well as the surface tension gradient over the weld pool, determine the weld shape and size. In addition, provided the welding current through one electrode increases and that through the other decreases, keeping the total current unchanged, the coupled arc behaviour and weld pool dynamic change significantly, while the weld shape and size show little change. The results demonstrate the necessity of a unified model in the study of the arc plasma and weld pool.

The motion of twin boundaries in Ni–Mn–Ga ferromagnetic shape memory alloy (FSMA) particles embedded in a polymer matrix has been proposed as an effective mechanism for the dissipation of vibration energy. Indirect evidence of the motion of these boundaries through vibrating sample magnetometer measurements on FSMA/polyurethane matrix composite is shown.

In a vibrational energy harvester, an external vibration causes relative motion between a permanent magnet and a magnetic field sensing element composed of a magnetostrictive material bonded to an electroactive material. The changing magnetic field causes a rotation of magnetization in the magnetostrictive material and the rotating magnetization generates a stress in the magnetostrictive material. The stress is transmitted to the electroactive material, which responds by generating electrical power.

The study was carried out in 1985-86 in Hainan Island where Plasmodium falciparum is resistant to chloroquine. Fifty cases of falciparum malaria were treated with 1800 mg amodiaquine for 3 days: the cure rate was 65.3%, and the mean time to clear fever and asexual parasitaemia was 30.7 and 60.3 hours, respectively; 34.7% of cases showed RI or RII recrudescence, and one patient's temperature did not come down to normal within 7 days.Twenty-one cases were treated with sulfadoxine-pyrimethamine (1500 mg and 75 mg, respectively): 19 were cured, I showed RI and another had an S or RI response; the mean time for fever control was 56.1 hours.Fifty cases were treated with amodiaquine plus sulfadoxine and 49 received amodiaquine plus sulfadoxine-pyrimethamine: the cure rate was 97.9% and 100%, respectively; the mean time for fever clearance was 25.0 and 25.7 hours and for parasite clearance 57.1 and 52.8 hours, respectively. These drug combinations gave much better results for cure and for symptom control than amodiaquine or sulfadoxine-pyrimethamine alone, and may be considered for treatment of chloroquine-resistant falciparum malaria.

In this paper, ferromagnetic shape memory alloys, most notably NiMnGa have received considerable attention because of the remarkable 6% to 10% field induced strains they have exhibited at room temperature in the magnetic fields of order 0.5 T. In order to address this question, the important technical properties that these materials exhibit will be reviewed and compared with those of competing active materials.