TiN/Ti multi-permeating alloying layer has been formed on the low carbon steel by means of the double glow-discharge plasma surface alloying technique and hollow-cathode effect. The alloying layer was detected by axio...TiN/Ti multi-permeating alloying layer has been formed on the low carbon steel by means of the double glow-discharge plasma surface alloying technique and hollow-cathode effect. The alloying layer was detected by axiovert 25 CA optical microscope with computer analyzing software （LEC）, GDA-2 glow discharge spectroscopy （GDS）, X-ray diffraction （XRD） and galvanochemical method. The results showed that the thickness of TiN/Ti multi-permeating alloying layer was about 10μm, the content of Ti on the surface was up to 63.48 wt% and the content of N was up to 12.46 wt%. The atom Ti and N concentrations changed gradually across the depth of the alloying layer and the preferred orientation of TiN/Ti alloying layer was crystal surface （200）. The multi-permeating alloying layer and substrate were combined through metallurgy. The surface appearances of the multi-permeating alloying layer were uniform and of a compact cellular structure. The hardness of the surface was about 1600-3000 HV0.1. The corrosion resistance of the permeating TiN/Ti alloying layer in 0.5 mol/L H2SO4 solution was greatly increased and the corrosion rate was only 0.3082 g/m^2. h.展开更多
Asphalt pavement is currently one of the main components in the construction of roads and bridges.However,from a practical point of view,various quality problems are prone to occur in the surface layer of asphalt pave...Asphalt pavement is currently one of the main components in the construction of roads and bridges.However,from a practical point of view,various quality problems are prone to occur in the surface layer of asphalt pavement,which will lead to the poor overall quality of road and bridge projects.Therefore,it should be applied reasonably.Advanced testing technologies are used to test the mixture quality,compaction,segregation,thickness,and other aspects of the asphalt pavement surface layer,so as to improve the quality of the asphalt pavement surface layer,and then improve the overall quality of road and bridge construction.Therefore,this paper mainly analyzes the technologies for asphalt pavement surface layer testing in road and bridge engineering construction.展开更多
To study the properties of a new surface-type infrared decoy,the numerical dispersion model and the infrared radiance model of the plates are established. In addition,the temperature of a single plate was measured dur...To study the properties of a new surface-type infrared decoy,the numerical dispersion model and the infrared radiance model of the plates are established. In addition,the temperature of a single plate was measured during combustion experiment,and the spatial position and infrared radiance of each plate are calculated in plate cloud by the two models respectively. Furthermore,the radar images of the plate cloud are simulated and analyzed in dependence of time and direction for single and multiple launching. The result shows that the surface-type infrared decoy can be a point source of interference when the missile is remote tracking. In the meanwhile,the plates cloud shelters the infrared characteristics of the plume and jets of aircraft when the missile is on IR imaging guidance mode. Moreover,With the analysis of the plate cloud dispersion at different intervals and the infrared radiation intensity in the case of different launching number,it can be concluded that a comfortable launching interval can maintain a continuous plate cloud,launching the decoys simultaneously increase the increment of the radiation intensity obviously,the multiple launching is an effective way to enhance the interference property of the decoy.展开更多
针对薄壁堆焊结构中裂纹类缺陷定位、定量检测的需要,采用TOFD(Time Of Flight Diffraction)超声检测技术对裂纹类缺陷进行了检测。研究了其超声衍射时间差法的检测特征,对获得的B、D扫描图像的特征进行了分析和解释。结果表明,该方法...针对薄壁堆焊结构中裂纹类缺陷定位、定量检测的需要,采用TOFD(Time Of Flight Diffraction)超声检测技术对裂纹类缺陷进行了检测。研究了其超声衍射时间差法的检测特征,对获得的B、D扫描图像的特征进行了分析和解释。结果表明,该方法可以检测到表面下2 mm^10 mm内的垂直裂缝,结合A扫描信号和B、D扫描图像的特征,能够有效地对裂纹状缺陷进行识别、定位和定量。该技术能为堆焊质量评价提供比较可靠准确的信息。展开更多
Bilayer humidity-responsive actuators are generally composed of actuating and supporting layers of different materials with largely different wettability.Such kinds of bilayer actuators suffer from low adhesive force ...Bilayer humidity-responsive actuators are generally composed of actuating and supporting layers of different materials with largely different wettability.Such kinds of bilayer actuators suffer from low adhesive force between the two layers during usage.This study demonstrates the preparation of humidity-responsive bilayer actuators that have the same materials in the actuating and supporting layers to avoid the adhesive issue.The bilayer actuators consist of a porous poly(acrylic acid)(PAA)/poly(allylamine hydrochloride)(PAH)layer and a nonporous PAA/PAH layer that are fabricated by exponentially layer-by-layer assembly method.At a high/low relative humidity(RH),the nonporous PAA/PAH layer can efficiently expand/shrink by absorbing/desorbing water while the volume expansion/shrinkage of the porous PAA/PAH layer in an environment with changed humidity is significantly suppressed by the micrometer-sized pores.The largely different expansion/shrinkage of the nonporous and porous PAA/PAH layers when subjected to humidity changes enables rapid and reversible rolling/unrolling motions of the bilayer actuator.The bilayer actuator shows a faster rolling speed and a larger bending curvature when subjected to a larger humidity increase.展开更多
基金supported by National Natural Science Foundation of China (No. 50374054)the Natural Science Foundation of Shanxi Province (No. 20031050)
文摘TiN/Ti multi-permeating alloying layer has been formed on the low carbon steel by means of the double glow-discharge plasma surface alloying technique and hollow-cathode effect. The alloying layer was detected by axiovert 25 CA optical microscope with computer analyzing software （LEC）, GDA-2 glow discharge spectroscopy （GDS）, X-ray diffraction （XRD） and galvanochemical method. The results showed that the thickness of TiN/Ti multi-permeating alloying layer was about 10μm, the content of Ti on the surface was up to 63.48 wt% and the content of N was up to 12.46 wt%. The atom Ti and N concentrations changed gradually across the depth of the alloying layer and the preferred orientation of TiN/Ti alloying layer was crystal surface （200）. The multi-permeating alloying layer and substrate were combined through metallurgy. The surface appearances of the multi-permeating alloying layer were uniform and of a compact cellular structure. The hardness of the surface was about 1600-3000 HV0.1. The corrosion resistance of the permeating TiN/Ti alloying layer in 0.5 mol/L H2SO4 solution was greatly increased and the corrosion rate was only 0.3082 g/m^2. h.
文摘Asphalt pavement is currently one of the main components in the construction of roads and bridges.However,from a practical point of view,various quality problems are prone to occur in the surface layer of asphalt pavement,which will lead to the poor overall quality of road and bridge projects.Therefore,it should be applied reasonably.Advanced testing technologies are used to test the mixture quality,compaction,segregation,thickness,and other aspects of the asphalt pavement surface layer,so as to improve the quality of the asphalt pavement surface layer,and then improve the overall quality of road and bridge construction.Therefore,this paper mainly analyzes the technologies for asphalt pavement surface layer testing in road and bridge engineering construction.
文摘To study the properties of a new surface-type infrared decoy,the numerical dispersion model and the infrared radiance model of the plates are established. In addition,the temperature of a single plate was measured during combustion experiment,and the spatial position and infrared radiance of each plate are calculated in plate cloud by the two models respectively. Furthermore,the radar images of the plate cloud are simulated and analyzed in dependence of time and direction for single and multiple launching. The result shows that the surface-type infrared decoy can be a point source of interference when the missile is remote tracking. In the meanwhile,the plates cloud shelters the infrared characteristics of the plume and jets of aircraft when the missile is on IR imaging guidance mode. Moreover,With the analysis of the plate cloud dispersion at different intervals and the infrared radiation intensity in the case of different launching number,it can be concluded that a comfortable launching interval can maintain a continuous plate cloud,launching the decoys simultaneously increase the increment of the radiation intensity obviously,the multiple launching is an effective way to enhance the interference property of the decoy.
基金financially supported by the National Basic Research Program (No. 2013CB834503)the National Natural Science Foundation of China (No. 21225419)
文摘Bilayer humidity-responsive actuators are generally composed of actuating and supporting layers of different materials with largely different wettability.Such kinds of bilayer actuators suffer from low adhesive force between the two layers during usage.This study demonstrates the preparation of humidity-responsive bilayer actuators that have the same materials in the actuating and supporting layers to avoid the adhesive issue.The bilayer actuators consist of a porous poly(acrylic acid)(PAA)/poly(allylamine hydrochloride)(PAH)layer and a nonporous PAA/PAH layer that are fabricated by exponentially layer-by-layer assembly method.At a high/low relative humidity(RH),the nonporous PAA/PAH layer can efficiently expand/shrink by absorbing/desorbing water while the volume expansion/shrinkage of the porous PAA/PAH layer in an environment with changed humidity is significantly suppressed by the micrometer-sized pores.The largely different expansion/shrinkage of the nonporous and porous PAA/PAH layers when subjected to humidity changes enables rapid and reversible rolling/unrolling motions of the bilayer actuator.The bilayer actuator shows a faster rolling speed and a larger bending curvature when subjected to a larger humidity increase.
