The Indian shield comprises a number of Archean–Paleoproterozoic cratonic blocks and predominantly Meso–Neoproterozoic mobile belts with Archean protoliths.All these ancient cratons were thought to be integral parts of
The influence of laser parameters on are beharior of laser-TIC, dauble-side welding was investigated by utilizing CCD sensor and intage processing methods. It was found that are images had an obvious transformation fr...The influence of laser parameters on are beharior of laser-TIC, dauble-side welding was investigated by utilizing CCD sensor and intage processing methods. It was found that are images had an obvious transformation from laser preheating to laser plasma ejected from the keyhole bottom, resulting in the phenomena of arc column convergence and arc root constrictian. The attraction phenomenon of the laser and the arc is also found in laser-TIG double-side welding. More noteworthy is that the behavior of arc attraction or constriction became much obvious at a lower current or laser plasma ejected from the keyhole bottom. The decrease in arc voltage had a certain relation u＇ith the improvement of arc stabilio.展开更多
In continuous wave CO2 laser-TlG hybrid welding process, the laser energy is not fully utilized because of the absorption and defocusing by plasma in the arc space. Therefore, the optimal welding result can only be ac...In continuous wave CO2 laser-TlG hybrid welding process, the laser energy is not fully utilized because of the absorption and defocusing by plasma in the arc space. Therefore, the optimal welding result can only be achieved in a limited energy range. In order to improve the welding performance further, a novel hybrid welding method--pulse CO2 laser-TIG arc hybrid welding by coordinated control is proposed and investigated. The experimental results indicate that, compared with continuous wave CO2 laser-TIG hybrid welding, the absorption and defocusing of laser energy by plasma are decreased further, and at the same time, the availability ratio of laser and arc energy can be increased when a coordinated frequency is controlled. As a result, the weld appearance is also improved as well as the weld depth is deepened. Furthermore, the effect of frequency and phase of pulse laser and TIG arc on the arc images and welding characteristics is also studied. However, the novel hybrid method has great potentials in the application of industrials from views of techniques and economy.展开更多
Novel Eu^(2+)-activated phosphate phosphors based on high-temperature phaseσ-Ba_(2)P_(2)O_(7),which is an unstable phase at room temperature,were synthesized for the first time by a melt synthesis technique using an ...Novel Eu^(2+)-activated phosphate phosphors based on high-temperature phaseσ-Ba_(2)P_(2)O_(7),which is an unstable phase at room temperature,were synthesized for the first time by a melt synthesis technique using an arc-imaging furnace.By doping Mg^(2+)into the host lattice,Eu^(2+)-activatedσ-Ba_(2)P_(2)O_(7)phosphors were successfully obtained in a single phase form of a hexagonal structure and the emission intensity was also effectively enhanced.展开更多
文摘The Indian shield comprises a number of Archean–Paleoproterozoic cratonic blocks and predominantly Meso–Neoproterozoic mobile belts with Archean protoliths.All these ancient cratons were thought to be integral parts of
文摘The influence of laser parameters on are beharior of laser-TIC, dauble-side welding was investigated by utilizing CCD sensor and intage processing methods. It was found that are images had an obvious transformation from laser preheating to laser plasma ejected from the keyhole bottom, resulting in the phenomena of arc column convergence and arc root constrictian. The attraction phenomenon of the laser and the arc is also found in laser-TIG double-side welding. More noteworthy is that the behavior of arc attraction or constriction became much obvious at a lower current or laser plasma ejected from the keyhole bottom. The decrease in arc voltage had a certain relation u＇ith the improvement of arc stabilio.
文摘In continuous wave CO2 laser-TlG hybrid welding process, the laser energy is not fully utilized because of the absorption and defocusing by plasma in the arc space. Therefore, the optimal welding result can only be achieved in a limited energy range. In order to improve the welding performance further, a novel hybrid welding method--pulse CO2 laser-TIG arc hybrid welding by coordinated control is proposed and investigated. The experimental results indicate that, compared with continuous wave CO2 laser-TIG hybrid welding, the absorption and defocusing of laser energy by plasma are decreased further, and at the same time, the availability ratio of laser and arc energy can be increased when a coordinated frequency is controlled. As a result, the weld appearance is also improved as well as the weld depth is deepened. Furthermore, the effect of frequency and phase of pulse laser and TIG arc on the arc images and welding characteristics is also studied. However, the novel hybrid method has great potentials in the application of industrials from views of techniques and economy.
基金supported by a project from NEDO,New Energy and Industrial Technology Development Organization(Rare Metal Substitute Materials Development Project Development of Technology for Reducing Tb and Eu Usage in Phosphors for Fluorescent Lamp by High-speed Material Synthesis and Evaluation).
文摘Novel Eu^(2+)-activated phosphate phosphors based on high-temperature phaseσ-Ba_(2)P_(2)O_(7),which is an unstable phase at room temperature,were synthesized for the first time by a melt synthesis technique using an arc-imaging furnace.By doping Mg^(2+)into the host lattice,Eu^(2+)-activatedσ-Ba_(2)P_(2)O_(7)phosphors were successfully obtained in a single phase form of a hexagonal structure and the emission intensity was also effectively enhanced.
