The formation mechanism for the equilateral triangle structure of the He-3(+) cluster is proposed. The curve of the total energy versus the internuclear distance R for this structure has been calculated by the method ...The formation mechanism for the equilateral triangle structure of the He-3(+) cluster is proposed. The curve of the total energy versus the internuclear distance R for this structure has been calculated by the method of a modified arrangement channel quantum mechanics. The result shows that the curve has a minimal -7.81373 a. u at R = 1.55 a(0). The binding energy of He-3(+) with respect to He+He++He was calculated to be 0.1064 a.u. (about 2.89 eV). This means that the He-3(+) cluster may be formed in the equilateral triangle structure stably by the interaction of He+ with two helium atoms.展开更多
The formation mechanism for the equilateral triangle structure of Lia cluster is proposed. The curve of the total energy versus the interatomic distance for this structure has been calculated by using the method of Go...The formation mechanism for the equilateral triangle structure of Lia cluster is proposed. The curve of the total energy versus the interatomic distance for this structure has been calculated by using the method of Gou's Modified Arrangement Channel Quantum Mechanics. The result shows that the curve has a minimal energy of-22.338 60 a.u at R = 5.82 ao. The total energy of Lia when R approaches co has the value of-22.284 09 a.u. This is also the total energy of three lithium atoms dissociated from Lia. The difference value of 0.0545 08 a.u. for the above two energy values is the dissociation energy of Li3 cluster, which is also its binding energy. Therefore the binding energy per lithium atom for Lia is 0.018 169 a.u. = 0.494 eV, which is greater than the binding energy of 0.453 eV per atom for Li2 calculated in a previous work. This means that the Li3 cluster may be formed in the equilateral triangle structure of side length R = 5.82ao stably with a stronger binding from the symmetrical interaction among the three lithium atoms.展开更多
With the purpose to understand better the role of information not only in communication systems,but actually in our environmental reality,this paper presented the model of Universal Triangle of Reality,composed by Mat...With the purpose to understand better the role of information not only in communication systems,but actually in our environmental reality,this paper presented the model of Universal Triangle of Reality,composed by Matter,Energy and Information,as fundamental constitutive components of this reality.Arguments coming from the field of physics,both at the cosmic and microparticles scale are presented,showing undoubtable conclusions that information is a fundamental component of reality in our material world.At the cosmic level,where the unusual high concentration of mass in the black holes constitutes a special state of matter,suitable for analysis of their special properties,the problem of the conservation principle of information is discussed.At the quantum level,the special unusual characteristics derived from the non-localization principle are also highlighted,together with information-involved problems and solutions.The Universal Triangle of Reality in the living systems reveals the high role of the involved information,both as the informational common organization on the entire evolution scale,and as the info-dynamics processes inside of own structure and resulted from interaction with the environment.The relevant advances in the approaching and understanding of the functionality of the living systems from informational point of view are highlighted,showing the high contribution of information concepts in understanding/solving of various older/recent problems in philosophy,neuroscience/neurology/psychiatry,neuro-physics/neuropsychology/behavior sciences,geriatrics/gerontology,biology and life sciences.展开更多
The formation mechanism for the equilateral triangle structure of the He3+ cluster is proposed. The curveof the total energy versus the internuclear distance R for this structure has been calculated by the method of a...The formation mechanism for the equilateral triangle structure of the He3+ cluster is proposed. The curveof the total energy versus the internuclear distance R for this structure has been calculated by the method of a modifiedarrangement channel quantum mechanics. The result shows that the curve has a minimal -7.81373 a.u at 1 = 1.55 a0.The binding energy of He3+ with respect to He+He+ +He was calculated to be 0.1064 a.u. (about 2.89 eV). This meansthat the He3+ cluster may be formed in the equilateral triangle structure stably by the interaction of He+ with two heliumatoms.展开更多
A real-time arc welding robot visual control system based on a local network with a multi-level hierarchy is developed in this paper. It consists of an intelligence and human-machine interface level, a motion planning...A real-time arc welding robot visual control system based on a local network with a multi-level hierarchy is developed in this paper. It consists of an intelligence and human-machine interface level, a motion planning level, a motion control level and a servo control level. The last three levels form a local real-time open robot controller, which realizes motion planning and motion control of a robot. A camera calibration method based on the relative movement of the end-effector connected to a robot is proposed and a method for tracking weld seam based on the structured light stereovision is provided. Combining the parameters of the cameras and laser plane, three groups of position values in Cartesian space are obtained for each feature point in a stripe projected on the weld seam. The accurate three-dimensional position of the edge points in the weld seam can be calculated from the obtained parameters with an information fusion algorithm. By calculating the weld seam parameter from position and image data, the movement parameters of the robot used for tracking can be determined. A swing welding experiment of type V groove weld is successfully conducted, the results of which show that the system has high resolution seam tracking in real-time, and works stably and efficiently.展开更多
A graded structural material(GSM)with a material transition from TA15 to TC11 was fabricated by wire arc additive manufacturing(WAAM)method.The grain morphology,chemical composition,microstructure and mechanical prope...A graded structural material(GSM)with a material transition from TA15 to TC11 was fabricated by wire arc additive manufacturing(WAAM)method.The grain morphology,chemical composition,microstructure and mechanical properties of the as-deposited GSM were all characterized to investigate their variations along the deposition direction.The results indicate that from TA15 to TC11,the grain size decreases and a transition from columnar grains to equiaxed grains occurs.The content of alloy element alters greatly within a short distance,and the width of the mutation zone is 800μm.Both TA15 and TC11 regions exhibit basketweave microstructure withα-phase andβ-phase.However,during the transition from TA15 to TC11,theα-lath becomes fine,which leads to an increase in microhardness.The tensile test shows that the bonding strength at the interface is higher than the longitudinal strength of TA15,and the lateral elongation at the interface is higher than that of TA15 and TC11.展开更多
The submerged arc brazing method was used to connect the tin-based babbit alloy with the steel matrix.The microstructure of the submerged arc brazed Babbitt interface layer on the surface of Q235 B steel was analyzed ...The submerged arc brazing method was used to connect the tin-based babbit alloy with the steel matrix.The microstructure of the submerged arc brazed Babbitt interface layer on the surface of Q235 B steel was analyzed by OM,SEM and EDS and the hardness properties of the joint interface layer were tested by MH-5 microhardness tester.the result of research shows that a layer of canine-shaped intermetallic compound with uneven thickness is formed at the interface,and the thickness is 10-20 μm.The interface layer includes two kinds of compound layers,namely the Fe Sn layer near the side of the steel substrate and FeSn layer near the side of the babbit.During the interfacial reaction process,Fe atoms in the steel matrix dissolve into the liquid babbit alloy and form a certain concentration gradient at the interface.The farther from the interface,the lower the Fe atom concentration.The growth of Gibbs free energy of Fe Sn is lower when the temperature is above 780.15 K,and the temperature during the welding process is much higher than 780.15 K,moreover the precipitation temperature of Fe Sn is higher.Therefore,in the subsequent cooling process,Fe Sn is first precipitated from the interface near the side of steel matrix and then FeSn is precipitated from the interface near the side of babbit alloy.Microhardness test showed that the intermetallic compound at the interface layer significantly improved the hardness properties.展开更多
Pure Ni nanopowders were successfully prepared by the method of anodic arc disch arged plasma with homemade experimental apparatus. The particle size, mircostruc ture and morphology of the particles by this process we...Pure Ni nanopowders were successfully prepared by the method of anodic arc disch arged plasma with homemade experimental apparatus. The particle size, mircostruc ture and morphology of the particles by this process were characterized via X-ra y powder diffraction (XRD), transmission electron microscopy (TEM) and the corre sponding selected area electron diffraction (SAED); The specific surface area an d pore parameters were investigated by multi-point full analysis of nitrogen ads orption-desorption isotherms at 77K by Brunauer- Emmett-Teller (BET) surface are a analyzer; The chemical composition were determined by X-ray energy dispersive spectrometry (XEDS) equipped in SEM and element analyze instrument. The experime nt results indicate that the samples by this method with high purity,the crystal structure of the particles is as same as the bulk material, is fcc structure, w ith average particle sizes about 47nm, ranging from 20 to 70nm, and distributed uniformly in spherical chain shapes, the specific surface areavis 14.23m2/g, po re volume of pore is 0.09cm3/g and average pore diameter is 23nm.展开更多
This work mainly articulated the effects of nozzle structure on arc characteristics in gas pool coupled activating TIG (GPCA-TIG) welding process by using Fluent Software. Different models were set up to adapt the d...This work mainly articulated the effects of nozzle structure on arc characteristics in gas pool coupled activating TIG (GPCA-TIG) welding process by using Fluent Software. Different models were set up to adapt the different torch structure during computer progress. The specific configuration of the welding torch made the gas flow in outer gas passage constrained. The nozzle structure has great influence on outer gas distribution because of the changing of coupling region between the outer active gas and molten pool surface. When the coupling degree is reduced or the outer gas passage become smaller, the oxygen in outer gas penetrates into the arc plasma and spreads to the arc region more easily. Owing to its cooling effects, the morphology of arc is contracted, and the arc temperature is increased. When the inner wall and the outer wall of outer gas passage are not parallel, the wide top and narrow bottom nozzle shape can bring more oxygen into the arc plasma, the arc is contracted and the peak temperature of arc rises a little more comparing to the narrow top and wide bottom one.展开更多
Galvanized steel sheets were joined by tungsten inert gas(TIG) and metal inert gas(MIG) brazing process using copper based filler. The results show that the joint zone hardness is higher than that of the base material...Galvanized steel sheets were joined by tungsten inert gas(TIG) and metal inert gas(MIG) brazing process using copper based filler. The results show that the joint zone hardness is higher than that of the base material or copper filler from the microhardness tests of TIG brazing specimens, and the fracture spot is at the base materials zone from the tensile tests of MIG brazing specimens. Examination using energy dispersive X-ray analysis reveals the presence of intermetallic compound Fe5Si3(Cu) in the joint. The dispersal of fine Fe5Si3(Cu) particles is the main strengthening factor for the joint. The Fe5Si3(Cu) particles are determined to arise from three sources, namely, spot micro-melt, whisker-like fragmentation and dissolve-separation actions.展开更多
Based on the fractal geometry, a new way for selecting material burden ratio and size distribution, named physical design of burden, which is different from stoichiometric weight of carbon burden, would play a more im...Based on the fractal geometry, a new way for selecting material burden ratio and size distribution, named physical design of burden, which is different from stoichiometric weight of carbon burden, would play a more important role in the operation of submerged arc furnace process. Cold simulation investigation was carried out to find how the fraction and size of metal balls affects the specific conductivity of charge mixture, by applying the percolation structure theory. A parameter equation, s/s=A(F-Fc)v, was suggested to calculate the specific conductivity of the charge mixture.展开更多
A novel hybrid visual servoing control method based on structured light vision is pro-posed for robotic arc welding with a general six degrees of freedom robot. It consists of a positioncontrol inner-loop in Cartesian...A novel hybrid visual servoing control method based on structured light vision is pro-posed for robotic arc welding with a general six degrees of freedom robot. It consists of a positioncontrol inner-loop in Cartesian space and two outer-loops. One is position-based visual control inCartesian space for moving in the direction of weld seam, i.e., weld seam tracking, another is image-based visual control in image space for adjustment to eliminate the errors in the process of tracking.A new Jacobian matrix from image space of the feature point on structured light stripe to Cartesianspace is provided for dierential movement of the end-e?ector. The control system model is simplifiedand its stability is discussed. An experiment of arc welding protected by gas CO2 for verifying iswell conducted.展开更多
The plasma-neutral gas structure generated in a magnesium cathodic arc operated with oxygen gas at a constant current of 50 A has been investigated by employing a simplified one-dimensional fluid model. The model incl...The plasma-neutral gas structure generated in a magnesium cathodic arc operated with oxygen gas at a constant current of 50 A has been investigated by employing a simplified one-dimensional fluid model. The model includes elastic collisions and charge-exchange reactions between metallic particles and gas molecules, and also generation and recombination of gaseous ions by electron impact. The distribution profiles of density and velocity of species along the axial direction were obtained at different background gas pressures (in the range of 0.7-3.0 Pa) by this model. A comparison with the experiments was made. At lower gas pressures, the depositing particles were mainly the metallic ions with a larger kinetic energy. As the gas pressure increased, the magnesium atoms with smaller kinetic energy acted as the dominant depositing species. Determined by the minimization of the system's total energy, MgO(100) or/and MgO(110) orientation appeared easily in the MgO films at lower gas pressures, and at higher gas pressures, the film preferred orientation was MgO(111).展开更多
An electric-arc plasma installation operated in the hidden anode arrangement is constructed and used for the preparation of carbon nanostructures. A contracted plasma arc generated by a plasma torch using an inert gas...An electric-arc plasma installation operated in the hidden anode arrangement is constructed and used for the preparation of carbon nanostructures. A contracted plasma arc generated by a plasma torch using an inert gas is used as heat source. The average mass temperature of arc is higher than 10^4 K, while its power density, which is directly transferred onto the electrode (anode), is - 2 kW/mm^2. The anode contact area formed on the electrode moves against the arc by way of shifting the electrode and is hidden completely in the interior of plasma gas stream moving towards it. As a result of both the direct plasma attack and the opposite movement of streams in the hidden anode contact area, a temperature higher than 6000 K is reached. Thus, intensive vaporization takes place, which forms a saturated plasma-gas-aerosol phase of the initial material of electrode (anode). This gas phase is mixed in and carried by the plasma stream. Over that mixed plasma stream, a controlled process of quenching (fixation) is carried out by twisted turbulent fluid streams. After the fixation, the resultant carbon nano-structures are caught by a filter and collected in a bunker.展开更多
Subsurface geological cross sections of 0 - 200 m depth were constructed using a dense drilling database of the Osaka Plain in the intra-arc Osaka Basin of the Japan island arc, an active plate margin. The cross secti...Subsurface geological cross sections of 0 - 200 m depth were constructed using a dense drilling database of the Osaka Plain in the intra-arc Osaka Basin of the Japan island arc, an active plate margin. The cross sections revealed the subsurface geological structures and the geometry of folding and faulting in the basin. The comparison between the constructed subsurface cross sections and the seismic sections of the basement and basin fills at a depth of 1500 - 2000 m showed that the basement and shallow subsurface structures are similar;however, the shallow cross sections were of higher resolution than the deep seismic profiles.展开更多
Forming and nanostructuring processes of TiN film by electric arc evaporation under the conditions of the reactive nitrogen gas deficit in the gas mixture (30%) have been investigated. The results of a technological e...Forming and nanostructuring processes of TiN film by electric arc evaporation under the conditions of the reactive nitrogen gas deficit in the gas mixture (30%) have been investigated. The results of a technological experiment, electron microscopic examination, X-ray diffraction phase analysis and mechanical testing of the film revealed that a significant increase in ion density and mobility leads to deterioration of the formation temperature conditions, structural and phase changes in TiN film and change of the main cubic phase (111)TiN on a hexagonal (101)TiN0.3. In the end repeated decrease of the the film microhardness with (101)TiN0.3 was caused not only by erosion of the film, but also because of change in the processes of its formation and nanostructuring in comparison with similar processes of the film with (111)TiN.展开更多
Graphite electrodes were used for the direct current (DC) arc discharge in water. And high-resolution transmission electron microscopy (HRTEM) was used to investigate the products. Based on the experimental phenom...Graphite electrodes were used for the direct current (DC) arc discharge in water. And high-resolution transmission electron microscopy (HRTEM) was used to investigate the products. Based on the experimental phenomena and nano-structure products, arc plasma characteristics in water were analyzed theoretically. Two growth regions and relevant growth modes were proposed to interpret the formation mechanisms of nano-structures by arc discharge in water. Furthermore, liquid nitrogen and cross magnetic field was applied to change the arcing state respectively, and new carbon nano-structures were obtained. Their formation mechanisms were also analyzed correspondingly.展开更多
Rotating arc sensor is a key device for automation welding. The vibration has a big influence on signal's correct collection and reliable automatic welding. In order to solve the vibration problem and the dynamic ...Rotating arc sensor is a key device for automation welding. The vibration has a big influence on signal's correct collection and reliable automatic welding. In order to solve the vibration problem and the dynamic balancing design with the restricted space,a bearing force analysis based dynamic balancing structure optimal design is proposed and implemented with the help of Pro/Engineer( PROE) and automatic dynamic analysis of mechanical systems( ADAMS) virtual prototype technology, in which three parameters of the counterbalance are considered. The method is suitable for the practical online adjustment. The simulation result shows that optimal design based counterbalance structure and parameters can satisfy the space requirement with lower vibration. The methodology provides a new idea for dynamic balancing design and adjustment of rotating arc sensor with adjustable rotation radius.展开更多
CrAlYN coatings with different Y contents(0,5 and 12 at.%)were deposited by cathodic arc evaporation to investigate the influence of Y-addition on the structure,mechanical and thermal properties of CrAlN coatings by u...CrAlYN coatings with different Y contents(0,5 and 12 at.%)were deposited by cathodic arc evaporation to investigate the influence of Y-addition on the structure,mechanical and thermal properties of CrAlN coatings by using X-ray diffraction,scanning electron microscopy,differential scanning calorimetry,thermal gravimetric analysis and nanoindentation.The structural transformation of single phase cubic Cr_(0.42)Al_(0.58)N and Cr_(0.39)Al_(0.56)Y_(0.05)N coatings to cubic−wurtzite mixed Cr_(0.32)Al_(0.56)Y_(0.12)N coating leads to a drop in hardness from(30.2±0.7)GPa of Cr_(0.42)Al_(0.58)N and(32.0±1.0)GPa of Cr_(0.39)Al_(0.56)Y_(0.05)N to(25.2±0.7)GPa of Cr_(0.32)Al_(0.56)Y_(0.12)N.The incorporation of 5 at.%Y retards the thermal decomposition of CrAlN,verified by the postponed precipitation of w-AlN and N-loss upon annealing.Correspondingly,Cr_(0.39)Al_(0.56)Y_(0.05)N coating consistently exhibits the highest hardness value during thermal annealing.Nevertheless,alloying with Y exerts an adverse effect on the oxidation resistance of CrAlN.展开更多
文摘The formation mechanism for the equilateral triangle structure of the He-3(+) cluster is proposed. The curve of the total energy versus the internuclear distance R for this structure has been calculated by the method of a modified arrangement channel quantum mechanics. The result shows that the curve has a minimal -7.81373 a. u at R = 1.55 a(0). The binding energy of He-3(+) with respect to He+He++He was calculated to be 0.1064 a.u. (about 2.89 eV). This means that the He-3(+) cluster may be formed in the equilateral triangle structure stably by the interaction of He+ with two helium atoms.
文摘The formation mechanism for the equilateral triangle structure of Lia cluster is proposed. The curve of the total energy versus the interatomic distance for this structure has been calculated by using the method of Gou's Modified Arrangement Channel Quantum Mechanics. The result shows that the curve has a minimal energy of-22.338 60 a.u at R = 5.82 ao. The total energy of Lia when R approaches co has the value of-22.284 09 a.u. This is also the total energy of three lithium atoms dissociated from Lia. The difference value of 0.0545 08 a.u. for the above two energy values is the dissociation energy of Li3 cluster, which is also its binding energy. Therefore the binding energy per lithium atom for Lia is 0.018 169 a.u. = 0.494 eV, which is greater than the binding energy of 0.453 eV per atom for Li2 calculated in a previous work. This means that the Li3 cluster may be formed in the equilateral triangle structure of side length R = 5.82ao stably with a stronger binding from the symmetrical interaction among the three lithium atoms.
文摘With the purpose to understand better the role of information not only in communication systems,but actually in our environmental reality,this paper presented the model of Universal Triangle of Reality,composed by Matter,Energy and Information,as fundamental constitutive components of this reality.Arguments coming from the field of physics,both at the cosmic and microparticles scale are presented,showing undoubtable conclusions that information is a fundamental component of reality in our material world.At the cosmic level,where the unusual high concentration of mass in the black holes constitutes a special state of matter,suitable for analysis of their special properties,the problem of the conservation principle of information is discussed.At the quantum level,the special unusual characteristics derived from the non-localization principle are also highlighted,together with information-involved problems and solutions.The Universal Triangle of Reality in the living systems reveals the high role of the involved information,both as the informational common organization on the entire evolution scale,and as the info-dynamics processes inside of own structure and resulted from interaction with the environment.The relevant advances in the approaching and understanding of the functionality of the living systems from informational point of view are highlighted,showing the high contribution of information concepts in understanding/solving of various older/recent problems in philosophy,neuroscience/neurology/psychiatry,neuro-physics/neuropsychology/behavior sciences,geriatrics/gerontology,biology and life sciences.
基金The project supported by National Natural Science Foundation of China under Grant No. 19974027
文摘The formation mechanism for the equilateral triangle structure of the He3+ cluster is proposed. The curveof the total energy versus the internuclear distance R for this structure has been calculated by the method of a modifiedarrangement channel quantum mechanics. The result shows that the curve has a minimal -7.81373 a.u at 1 = 1.55 a0.The binding energy of He3+ with respect to He+He+ +He was calculated to be 0.1064 a.u. (about 2.89 eV). This meansthat the He3+ cluster may be formed in the equilateral triangle structure stably by the interaction of He+ with two heliumatoms.
基金This work was supported by the National High Technology Research and Development Program of China under Grant 2002AA422160 by the National Key Fundamental Research and the Devel-opment Project of China (973) under Grant 2002CB312200.
文摘A real-time arc welding robot visual control system based on a local network with a multi-level hierarchy is developed in this paper. It consists of an intelligence and human-machine interface level, a motion planning level, a motion control level and a servo control level. The last three levels form a local real-time open robot controller, which realizes motion planning and motion control of a robot. A camera calibration method based on the relative movement of the end-effector connected to a robot is proposed and a method for tracking weld seam based on the structured light stereovision is provided. Combining the parameters of the cameras and laser plane, three groups of position values in Cartesian space are obtained for each feature point in a stripe projected on the weld seam. The accurate three-dimensional position of the edge points in the weld seam can be calculated from the obtained parameters with an information fusion algorithm. By calculating the weld seam parameter from position and image data, the movement parameters of the robot used for tracking can be determined. A swing welding experiment of type V groove weld is successfully conducted, the results of which show that the system has high resolution seam tracking in real-time, and works stably and efficiently.
基金financial supports from the National Natural Science Foundation of China(Nos.51875041,51875042)。
文摘A graded structural material(GSM)with a material transition from TA15 to TC11 was fabricated by wire arc additive manufacturing(WAAM)method.The grain morphology,chemical composition,microstructure and mechanical properties of the as-deposited GSM were all characterized to investigate their variations along the deposition direction.The results indicate that from TA15 to TC11,the grain size decreases and a transition from columnar grains to equiaxed grains occurs.The content of alloy element alters greatly within a short distance,and the width of the mutation zone is 800μm.Both TA15 and TC11 regions exhibit basketweave microstructure withα-phase andβ-phase.However,during the transition from TA15 to TC11,theα-lath becomes fine,which leads to an increase in microhardness.The tensile test shows that the bonding strength at the interface is higher than the longitudinal strength of TA15,and the lateral elongation at the interface is higher than that of TA15 and TC11.
基金supported by the University Natural Science Research Project of Jiangsu Province(Grant No.15KJA460006)
文摘The submerged arc brazing method was used to connect the tin-based babbit alloy with the steel matrix.The microstructure of the submerged arc brazed Babbitt interface layer on the surface of Q235 B steel was analyzed by OM,SEM and EDS and the hardness properties of the joint interface layer were tested by MH-5 microhardness tester.the result of research shows that a layer of canine-shaped intermetallic compound with uneven thickness is formed at the interface,and the thickness is 10-20 μm.The interface layer includes two kinds of compound layers,namely the Fe Sn layer near the side of the steel substrate and FeSn layer near the side of the babbit.During the interfacial reaction process,Fe atoms in the steel matrix dissolve into the liquid babbit alloy and form a certain concentration gradient at the interface.The farther from the interface,the lower the Fe atom concentration.The growth of Gibbs free energy of Fe Sn is lower when the temperature is above 780.15 K,and the temperature during the welding process is much higher than 780.15 K,moreover the precipitation temperature of Fe Sn is higher.Therefore,in the subsequent cooling process,Fe Sn is first precipitated from the interface near the side of steel matrix and then FeSn is precipitated from the interface near the side of babbit alloy.Microhardness test showed that the intermetallic compound at the interface layer significantly improved the hardness properties.
基金This work was supported by the Natural Science Foundation of Gansu Province,China(No.3ZS042-B25-017).
文摘Pure Ni nanopowders were successfully prepared by the method of anodic arc disch arged plasma with homemade experimental apparatus. The particle size, mircostruc ture and morphology of the particles by this process were characterized via X-ra y powder diffraction (XRD), transmission electron microscopy (TEM) and the corre sponding selected area electron diffraction (SAED); The specific surface area an d pore parameters were investigated by multi-point full analysis of nitrogen ads orption-desorption isotherms at 77K by Brunauer- Emmett-Teller (BET) surface are a analyzer; The chemical composition were determined by X-ray energy dispersive spectrometry (XEDS) equipped in SEM and element analyze instrument. The experime nt results indicate that the samples by this method with high purity,the crystal structure of the particles is as same as the bulk material, is fcc structure, w ith average particle sizes about 47nm, ranging from 20 to 70nm, and distributed uniformly in spherical chain shapes, the specific surface areavis 14.23m2/g, po re volume of pore is 0.09cm3/g and average pore diameter is 23nm.
基金supported by National Natural Science Foundation of China(Grant No.51265029)
文摘This work mainly articulated the effects of nozzle structure on arc characteristics in gas pool coupled activating TIG (GPCA-TIG) welding process by using Fluent Software. Different models were set up to adapt the different torch structure during computer progress. The specific configuration of the welding torch made the gas flow in outer gas passage constrained. The nozzle structure has great influence on outer gas distribution because of the changing of coupling region between the outer active gas and molten pool surface. When the coupling degree is reduced or the outer gas passage become smaller, the oxygen in outer gas penetrates into the arc plasma and spreads to the arc region more easily. Owing to its cooling effects, the morphology of arc is contracted, and the arc temperature is increased. When the inner wall and the outer wall of outer gas passage are not parallel, the wide top and narrow bottom nozzle shape can bring more oxygen into the arc plasma, the arc is contracted and the peak temperature of arc rises a little more comparing to the narrow top and wide bottom one.
基金Project (50475051) supported by the National Natural Science Foundation of China
文摘Galvanized steel sheets were joined by tungsten inert gas(TIG) and metal inert gas(MIG) brazing process using copper based filler. The results show that the joint zone hardness is higher than that of the base material or copper filler from the microhardness tests of TIG brazing specimens, and the fracture spot is at the base materials zone from the tensile tests of MIG brazing specimens. Examination using energy dispersive X-ray analysis reveals the presence of intermetallic compound Fe5Si3(Cu) in the joint. The dispersal of fine Fe5Si3(Cu) particles is the main strengthening factor for the joint. The Fe5Si3(Cu) particles are determined to arise from three sources, namely, spot micro-melt, whisker-like fragmentation and dissolve-separation actions.
基金Supported by the National Natural Science Foundation of China (No.50274013)
文摘Based on the fractal geometry, a new way for selecting material burden ratio and size distribution, named physical design of burden, which is different from stoichiometric weight of carbon burden, would play a more important role in the operation of submerged arc furnace process. Cold simulation investigation was carried out to find how the fraction and size of metal balls affects the specific conductivity of charge mixture, by applying the percolation structure theory. A parameter equation, s/s=A(F-Fc)v, was suggested to calculate the specific conductivity of the charge mixture.
文摘A novel hybrid visual servoing control method based on structured light vision is pro-posed for robotic arc welding with a general six degrees of freedom robot. It consists of a positioncontrol inner-loop in Cartesian space and two outer-loops. One is position-based visual control inCartesian space for moving in the direction of weld seam, i.e., weld seam tracking, another is image-based visual control in image space for adjustment to eliminate the errors in the process of tracking.A new Jacobian matrix from image space of the feature point on structured light stripe to Cartesianspace is provided for dierential movement of the end-e?ector. The control system model is simplifiedand its stability is discussed. An experiment of arc welding protected by gas CO2 for verifying iswell conducted.
基金supported by Hi-Tech Research and Development Program of China(No.2003AA311122)
文摘The plasma-neutral gas structure generated in a magnesium cathodic arc operated with oxygen gas at a constant current of 50 A has been investigated by employing a simplified one-dimensional fluid model. The model includes elastic collisions and charge-exchange reactions between metallic particles and gas molecules, and also generation and recombination of gaseous ions by electron impact. The distribution profiles of density and velocity of species along the axial direction were obtained at different background gas pressures (in the range of 0.7-3.0 Pa) by this model. A comparison with the experiments was made. At lower gas pressures, the depositing particles were mainly the metallic ions with a larger kinetic energy. As the gas pressure increased, the magnesium atoms with smaller kinetic energy acted as the dominant depositing species. Determined by the minimization of the system's total energy, MgO(100) or/and MgO(110) orientation appeared easily in the MgO films at lower gas pressures, and at higher gas pressures, the film preferred orientation was MgO(111).
文摘An electric-arc plasma installation operated in the hidden anode arrangement is constructed and used for the preparation of carbon nanostructures. A contracted plasma arc generated by a plasma torch using an inert gas is used as heat source. The average mass temperature of arc is higher than 10^4 K, while its power density, which is directly transferred onto the electrode (anode), is - 2 kW/mm^2. The anode contact area formed on the electrode moves against the arc by way of shifting the electrode and is hidden completely in the interior of plasma gas stream moving towards it. As a result of both the direct plasma attack and the opposite movement of streams in the hidden anode contact area, a temperature higher than 6000 K is reached. Thus, intensive vaporization takes place, which forms a saturated plasma-gas-aerosol phase of the initial material of electrode (anode). This gas phase is mixed in and carried by the plasma stream. Over that mixed plasma stream, a controlled process of quenching (fixation) is carried out by twisted turbulent fluid streams. After the fixation, the resultant carbon nano-structures are caught by a filter and collected in a bunker.
文摘Subsurface geological cross sections of 0 - 200 m depth were constructed using a dense drilling database of the Osaka Plain in the intra-arc Osaka Basin of the Japan island arc, an active plate margin. The cross sections revealed the subsurface geological structures and the geometry of folding and faulting in the basin. The comparison between the constructed subsurface cross sections and the seismic sections of the basement and basin fills at a depth of 1500 - 2000 m showed that the basement and shallow subsurface structures are similar;however, the shallow cross sections were of higher resolution than the deep seismic profiles.
文摘Forming and nanostructuring processes of TiN film by electric arc evaporation under the conditions of the reactive nitrogen gas deficit in the gas mixture (30%) have been investigated. The results of a technological experiment, electron microscopic examination, X-ray diffraction phase analysis and mechanical testing of the film revealed that a significant increase in ion density and mobility leads to deterioration of the formation temperature conditions, structural and phase changes in TiN film and change of the main cubic phase (111)TiN on a hexagonal (101)TiN0.3. In the end repeated decrease of the the film microhardness with (101)TiN0.3 was caused not only by erosion of the film, but also because of change in the processes of its formation and nanostructuring in comparison with similar processes of the film with (111)TiN.
基金National Natural Science Foundation of China (No.50377030)
文摘Graphite electrodes were used for the direct current (DC) arc discharge in water. And high-resolution transmission electron microscopy (HRTEM) was used to investigate the products. Based on the experimental phenomena and nano-structure products, arc plasma characteristics in water were analyzed theoretically. Two growth regions and relevant growth modes were proposed to interpret the formation mechanisms of nano-structures by arc discharge in water. Furthermore, liquid nitrogen and cross magnetic field was applied to change the arcing state respectively, and new carbon nano-structures were obtained. Their formation mechanisms were also analyzed correspondingly.
基金Foundations of Jiangxi Provincial Department of Science and Technology,China(Nos.20132BAB206028,20132BAB206030)
文摘Rotating arc sensor is a key device for automation welding. The vibration has a big influence on signal's correct collection and reliable automatic welding. In order to solve the vibration problem and the dynamic balancing design with the restricted space,a bearing force analysis based dynamic balancing structure optimal design is proposed and implemented with the help of Pro/Engineer( PROE) and automatic dynamic analysis of mechanical systems( ADAMS) virtual prototype technology, in which three parameters of the counterbalance are considered. The method is suitable for the practical online adjustment. The simulation result shows that optimal design based counterbalance structure and parameters can satisfy the space requirement with lower vibration. The methodology provides a new idea for dynamic balancing design and adjustment of rotating arc sensor with adjustable rotation radius.
基金The authors are grateful for the financial supports from the National Natural Science Foundation of China(No.51775560).
文摘CrAlYN coatings with different Y contents(0,5 and 12 at.%)were deposited by cathodic arc evaporation to investigate the influence of Y-addition on the structure,mechanical and thermal properties of CrAlN coatings by using X-ray diffraction,scanning electron microscopy,differential scanning calorimetry,thermal gravimetric analysis and nanoindentation.The structural transformation of single phase cubic Cr_(0.42)Al_(0.58)N and Cr_(0.39)Al_(0.56)Y_(0.05)N coatings to cubic−wurtzite mixed Cr_(0.32)Al_(0.56)Y_(0.12)N coating leads to a drop in hardness from(30.2±0.7)GPa of Cr_(0.42)Al_(0.58)N and(32.0±1.0)GPa of Cr_(0.39)Al_(0.56)Y_(0.05)N to(25.2±0.7)GPa of Cr_(0.32)Al_(0.56)Y_(0.12)N.The incorporation of 5 at.%Y retards the thermal decomposition of CrAlN,verified by the postponed precipitation of w-AlN and N-loss upon annealing.Correspondingly,Cr_(0.39)Al_(0.56)Y_(0.05)N coating consistently exhibits the highest hardness value during thermal annealing.Nevertheless,alloying with Y exerts an adverse effect on the oxidation resistance of CrAlN.