The multiphoton ionization (MPI) of diethylamine is first reported in this paper. Atime-of-flight mass spectrometer was used in the experiment under collision-free condition. MPImass spectra were measured in the regio...The multiphoton ionization (MPI) of diethylamine is first reported in this paper. Atime-of-flight mass spectrometer was used in the experiment under collision-free condition. MPImass spectra were measured in the region of 464 ～486 nm using a dye laser and at double fre-quency of a Nd:YAG laser. Molecular ion was created through resonance enhanced multiphotonionization (REMPI) via Rydberg states. Fragment, ion distribution was formed through “lladderswitching” process. The experimentai demonstration of the process is reported for the first timeby the discussion of dependence of ion relative, abundance on laser wavelength and energy. Thecompetition bet,ween further up-pumping and fragmentation of Parent ion also exists, and higherlaser intensity favors the former.展开更多
Conventional thermoacoustic engines have a stack pore radius that is almost constant in the axial direction. Hence, a thermoacoustic engine is expected to improve the energy conversion efficiency using a multistage st...Conventional thermoacoustic engines have a stack pore radius that is almost constant in the axial direction. Hence, a thermoacoustic engine is expected to improve the energy conversion efficiency using a multistage stack with multiple pore radii. The stack comprises several bundles of numerous narrow tubes with specified pore radii. The optimum pore radius of the stack is determined by the oscillation frequency and the temperature in the stack. Consequently, the suitable pore radius changes in the axial direction, because the temperature gradient exists along the stack axis. Therefore, a multistage stack with multiple pore radii is introduced, which achieves a desired optimum pore radius everywhere in the stack. The energy conversion efficiency of the multistage stack, which was studied experimentally for a straight-tube type thermoacoustic engine, was compared with that of a conventional single-stage stack. In these experiments, the improvement of the energy conversion efficiency was confirmed. A numerical method with the transmittance matrix to include the effect of a multistage stack was used, and good agreement between experimental and numerical results was obtained. The results make a future possibilities for stack design intended to higher thermoacoustic engine efficiency expect.展开更多
文摘The multiphoton ionization (MPI) of diethylamine is first reported in this paper. Atime-of-flight mass spectrometer was used in the experiment under collision-free condition. MPImass spectra were measured in the region of 464 ～486 nm using a dye laser and at double fre-quency of a Nd:YAG laser. Molecular ion was created through resonance enhanced multiphotonionization (REMPI) via Rydberg states. Fragment, ion distribution was formed through “lladderswitching” process. The experimentai demonstration of the process is reported for the first timeby the discussion of dependence of ion relative, abundance on laser wavelength and energy. Thecompetition bet,ween further up-pumping and fragmentation of Parent ion also exists, and higherlaser intensity favors the former.
文摘Conventional thermoacoustic engines have a stack pore radius that is almost constant in the axial direction. Hence, a thermoacoustic engine is expected to improve the energy conversion efficiency using a multistage stack with multiple pore radii. The stack comprises several bundles of numerous narrow tubes with specified pore radii. The optimum pore radius of the stack is determined by the oscillation frequency and the temperature in the stack. Consequently, the suitable pore radius changes in the axial direction, because the temperature gradient exists along the stack axis. Therefore, a multistage stack with multiple pore radii is introduced, which achieves a desired optimum pore radius everywhere in the stack. The energy conversion efficiency of the multistage stack, which was studied experimentally for a straight-tube type thermoacoustic engine, was compared with that of a conventional single-stage stack. In these experiments, the improvement of the energy conversion efficiency was confirmed. A numerical method with the transmittance matrix to include the effect of a multistage stack was used, and good agreement between experimental and numerical results was obtained. The results make a future possibilities for stack design intended to higher thermoacoustic engine efficiency expect.
