The formation mechanism of the discharge spot at a bottom of a lead wire in a fluorescent lamp at end-of-life is investigated. When the lamp at end-of life is ignited by applying high voltage, glow-like discharge is f...The formation mechanism of the discharge spot at a bottom of a lead wire in a fluorescent lamp at end-of-life is investigated. When the lamp at end-of life is ignited by applying high voltage, glow-like discharge is formed on the surface of the lead wire. A few seconds later, a bright spot is formed at the bottom 0fthe lead-wire. Then the stem glass on which the lead-wires are mounted begins to melt. High electric field is formed between the surface of the lead-wire and the stem glass surrounding the lead wire. Then discharge spot will be formed at the contact portion of the lead wire to the stem glass by this high electric field. To prevent discharge spot formation at the bottom of the lead wire, the metal ring is set to encircle the lead wire and is connected to the lead wire potential through a resistor. By this configuration, discharge spot formation is effectively suppressed. The mechanism for preventing hot discharge spot formation by the metal ring is discussed.展开更多
An effective design method of freeform micro lens array is presented for shaping varied laser beams into prescribed rectangular illumination. The variable separation mapping is applied to design concave freeform surfa...An effective design method of freeform micro lens array is presented for shaping varied laser beams into prescribed rectangular illumination. The variable separation mapping is applied to design concave freeform surfaces for constructing a freeform lens array. Several dedicated examples show that the designed freeform optical lens array can achieve a prescribed rectangular illumination pattern, especially without considering the initial states of incident laser beams. Both high collection efficiency and good spatial uniformity can be available simultaneously. Tolerance analysis is also performed to demonstrate that this optical device can well avoid fabricating difficulty in actual applications.展开更多
Photodeachment of H^-near a reflective spherical surface was studied by Haneef et al.[J.Phys.B:At.Mol.Opt.Phys.44(2011)195004]using a theoretical imaging method.The total cross section displays interesting oscillation...Photodeachment of H^-near a reflective spherical surface was studied by Haneef et al.[J.Phys.B:At.Mol.Opt.Phys.44(2011)195004]using a theoretical imaging method.The total cross section displays interesting oscillations.Here we re-examine the total photodetachment cross section of this system by directly applying the standard closed-orbit theory.Our result for the total cross section differs from the result obtained by Haneef et al.The difference between the two results vanishes in the limit of large radius of the reflective sphere.We argue that the theoretical imaging method developed originally for photodetachment near a Hat surface can not be directly applied to the present system.展开更多
文摘The formation mechanism of the discharge spot at a bottom of a lead wire in a fluorescent lamp at end-of-life is investigated. When the lamp at end-of life is ignited by applying high voltage, glow-like discharge is formed on the surface of the lead wire. A few seconds later, a bright spot is formed at the bottom 0fthe lead-wire. Then the stem glass on which the lead-wires are mounted begins to melt. High electric field is formed between the surface of the lead-wire and the stem glass surrounding the lead wire. Then discharge spot will be formed at the contact portion of the lead wire to the stem glass by this high electric field. To prevent discharge spot formation at the bottom of the lead wire, the metal ring is set to encircle the lead wire and is connected to the lead wire potential through a resistor. By this configuration, discharge spot formation is effectively suppressed. The mechanism for preventing hot discharge spot formation by the metal ring is discussed.
基金supported by the National Natural Science Foundation of China(No.61405037)the Science and Technology Project of Fujian Province(No.2015H4014)
文摘An effective design method of freeform micro lens array is presented for shaping varied laser beams into prescribed rectangular illumination. The variable separation mapping is applied to design concave freeform surfaces for constructing a freeform lens array. Several dedicated examples show that the designed freeform optical lens array can achieve a prescribed rectangular illumination pattern, especially without considering the initial states of incident laser beams. Both high collection efficiency and good spatial uniformity can be available simultaneously. Tolerance analysis is also performed to demonstrate that this optical device can well avoid fabricating difficulty in actual applications.
基金Supported by National Natural Science Foundation of China under Grant Nos.11474079 and 11421063
文摘Photodeachment of H^-near a reflective spherical surface was studied by Haneef et al.[J.Phys.B:At.Mol.Opt.Phys.44(2011)195004]using a theoretical imaging method.The total cross section displays interesting oscillations.Here we re-examine the total photodetachment cross section of this system by directly applying the standard closed-orbit theory.Our result for the total cross section differs from the result obtained by Haneef et al.The difference between the two results vanishes in the limit of large radius of the reflective sphere.We argue that the theoretical imaging method developed originally for photodetachment near a Hat surface can not be directly applied to the present system.
