Endoscopic xenon ion laser induced autofluorescence spectra in various gastric diseases were tested in 104 patients diagnosed by endoscopy and biopsy, including 28 gastric cancer, 9 gastric ulcer, 46 chronic atrophic ...Endoscopic xenon ion laser induced autofluorescence spectra in various gastric diseases were tested in 104 patients diagnosed by endoscopy and biopsy, including 28 gastric cancer, 9 gastric ulcer, 46 chronic atrophic gastritis, and 21 superficial gastritis. The autofluorescence spectrum excited with the 365 nm line of pulsed xenon ion laser was measured. The xenon ion laser beam having an output energy of 0.5 mJ with a duration of 0.6μs and a repetition rate of 10 Hz was used as the excitation source. A coaxial optical cable for laser light and autofluorescent light transmission was inserted via the biopsy channel of an endoscope into the cavity of stomach. The tip of opitcal cable was aimed at the gastric tissue and autofluorescence spectrum was plotted on X-Y recorder. As the monochromator scanned in the range 500-750 nm, a single-pulse fluorescence spectrum could be obtained by using an optical multichannel analyser, and then this fluorescence spectrum was stored in the computer. The whole procedure could be completed within 15 seconds. The results of the present study show that autofluorescence spectra of gastric cancer have characteristic peaks near 630 nm and 690 nm, while no such peaks appear in the spectra of the corresponding normal regions. A consistency of 75% was observed in gastric cancer as compared with the pathologic diagnosis. It is claimed that this is a harmless, safe, simple, and fast procedure in the diagnosis of gastric cancer.展开更多
放电室磁场的优化设计是离子推力器结构改进设计的关键技术之一,直接影响到推进剂电离效率和整机工作稳定性。针对深空探测等空间轨道任务对20 cm氙离子推力器应用需求,利用电磁体磁感应强度实时可调的优势,获得了给定工作模式下20 cm...放电室磁场的优化设计是离子推力器结构改进设计的关键技术之一,直接影响到推进剂电离效率和整机工作稳定性。针对深空探测等空间轨道任务对20 cm氙离子推力器应用需求,利用电磁体磁感应强度实时可调的优势,获得了给定工作模式下20 cm氙离子推力器放电室磁场最优构型及其磁感应强度的最佳分布。在此基础上,运用等效磁通理论,明确了产生相同磁场构型及其磁感应强度分布的永磁体结构尺寸。将20 cm氙离子推力器放电室磁场优化前后的性能进行对比,结果表明:在不改变整机结构的情况下,放电室磁场优化后推力可提升50%,由40 m N提高到60 m N,比冲提高到3 500 s,效率提高到65%。通过磁场优化,使得20 cm氙离子推力器具备了在40 m N和60 m N双模式工作的能力。研究为高效、稳定工作的离子推力器磁场优化提供方法。展开更多
The chemical shift of Na-23 in excimer NaXe was measured by using nuclear magnetic resonance (NMR) spectra, which is in good agreement with the theoretical value obtained by ab initio calculations. The bond length, di...The chemical shift of Na-23 in excimer NaXe was measured by using nuclear magnetic resonance (NMR) spectra, which is in good agreement with the theoretical value obtained by ab initio calculations. The bond length, dissociation energy, dipole of NaXe and Mulliken charges at Na and Xe in NaXe were calculated, respectively. The spectra of ultraviolet (UV) fluorescence and surface-enhanced Raman scattering of NaXe were also measured.展开更多
文摘Endoscopic xenon ion laser induced autofluorescence spectra in various gastric diseases were tested in 104 patients diagnosed by endoscopy and biopsy, including 28 gastric cancer, 9 gastric ulcer, 46 chronic atrophic gastritis, and 21 superficial gastritis. The autofluorescence spectrum excited with the 365 nm line of pulsed xenon ion laser was measured. The xenon ion laser beam having an output energy of 0.5 mJ with a duration of 0.6μs and a repetition rate of 10 Hz was used as the excitation source. A coaxial optical cable for laser light and autofluorescent light transmission was inserted via the biopsy channel of an endoscope into the cavity of stomach. The tip of opitcal cable was aimed at the gastric tissue and autofluorescence spectrum was plotted on X-Y recorder. As the monochromator scanned in the range 500-750 nm, a single-pulse fluorescence spectrum could be obtained by using an optical multichannel analyser, and then this fluorescence spectrum was stored in the computer. The whole procedure could be completed within 15 seconds. The results of the present study show that autofluorescence spectra of gastric cancer have characteristic peaks near 630 nm and 690 nm, while no such peaks appear in the spectra of the corresponding normal regions. A consistency of 75% was observed in gastric cancer as compared with the pathologic diagnosis. It is claimed that this is a harmless, safe, simple, and fast procedure in the diagnosis of gastric cancer.
文摘放电室磁场的优化设计是离子推力器结构改进设计的关键技术之一,直接影响到推进剂电离效率和整机工作稳定性。针对深空探测等空间轨道任务对20 cm氙离子推力器应用需求,利用电磁体磁感应强度实时可调的优势,获得了给定工作模式下20 cm氙离子推力器放电室磁场最优构型及其磁感应强度的最佳分布。在此基础上,运用等效磁通理论,明确了产生相同磁场构型及其磁感应强度分布的永磁体结构尺寸。将20 cm氙离子推力器放电室磁场优化前后的性能进行对比,结果表明:在不改变整机结构的情况下,放电室磁场优化后推力可提升50%,由40 m N提高到60 m N,比冲提高到3 500 s,效率提高到65%。通过磁场优化,使得20 cm氙离子推力器具备了在40 m N和60 m N双模式工作的能力。研究为高效、稳定工作的离子推力器磁场优化提供方法。
文摘The chemical shift of Na-23 in excimer NaXe was measured by using nuclear magnetic resonance (NMR) spectra, which is in good agreement with the theoretical value obtained by ab initio calculations. The bond length, dissociation energy, dipole of NaXe and Mulliken charges at Na and Xe in NaXe were calculated, respectively. The spectra of ultraviolet (UV) fluorescence and surface-enhanced Raman scattering of NaXe were also measured.
