We investigate the squeezing properties of the cavity field in the degenerate two-photon Jaynes Cummings model. Compared with the one-photon Jaynes-Cummings model, the squeezing is more pronounced in the case of two-p...We investigate the squeezing properties of the cavity field in the degenerate two-photon Jaynes Cummings model. Compared with the one-photon Jaynes-Cummings model, the squeezing is more pronounced in the case of two-photon Jaynes-Cummings model under certain conditions.展开更多
As one of the interesting optical techniques for measurements of the velocity,the spatial filtering method is treated briefly in this paper.We shown theoretical analysis and calculation of spatial filtering velocimetr...As one of the interesting optical techniques for measurements of the velocity,the spatial filtering method is treated briefly in this paper.We shown theoretical analysis and calculation of spatial filtering velocimetry,and discussed two-dimensional measurements of the velocity.About the data processing,we used A/D conversion and interfaced with a microcomputer,so that the data can be processed automatically by the microcomputer.The preliminary experiment was performed and the experimental results show the usefulness of the present method for measurements of the velocity.展开更多
The system principle and configuration of the double differential pressure method for measuring oil tank level are presented. The fundamental method and circuit of fiber optic transmission are analyzed .The accuracy a...The system principle and configuration of the double differential pressure method for measuring oil tank level are presented. The fundamental method and circuit of fiber optic transmission are analyzed .The accuracy and security of level measurement in the oil tanks have been greatly improved.展开更多
Objective To evaluate the variations of intraocular pressure （lOP） in suspected open-angle glaucoma （OAG） patients. Methods The variations of lOP were measured in 216 eyes of suspected OAG patients at 4-hour inter...Objective To evaluate the variations of intraocular pressure （lOP） in suspected open-angle glaucoma （OAG） patients. Methods The variations of lOP were measured in 216 eyes of suspected OAG patients at 4-hour intervals for 48 h. Based on the results of the serial lOP measurements, optic disc changed and visual field defected, the patients were diagnosed as primary OAG （ POAG ）, normal tension glaucoma （NTG）, ocular hypertension （ OHT） , or physiologic cup （PC）. Results After the serial lOP measurements, 16. 7% of the suspected OAG patients were diagnosed as POAG, 32. 4% as NTG, 24. 5% as OHT, and 26. 4% as PC. The highest percentages of the POAG group had peak lOP at 8 AM （19. 4% ） and their trough lOP at 10 PM （27. 8% ） ; the NTG group had peak lOP at 12 AM （18. 6% ） and their trough lOP at 12 PM （22. 9% ） ; the OHT group had peak lOP at 4 AM （22. 6% ） and their trough lOP at 10 PM （26. 4% ） ; and the PC group had peak lOP at 4 AM （ 21. 1% ） and their trough lOP at 12 PM （ 21. 1% ）. The percentages of peak lOP outside clinic （ 8 AM - 4 PM） in the POAG, NTG, OHT and PC groups were 55. 6%, 50. 0%, 58. 4% and 45. 7%, respectively. The mean magnitude of variance was 5. 1 - 6. 7 mmHg in those suspected OAG patients. There was a strong positive correlation in lOP between both eyes at each time point of measurement and the variation curves of the right and left eyes had parallel profiles in those suspected OAG patients. Conclusion Serial measurement of lOP is still needed, in order not to miss the peak and the trough lOP readings in suspected OAG patients, which helps in better management of glaucoma.展开更多
The ratio measurement by means of the sensing optical fiber and the reference fiber with different beginning positions, and the technique to improve the stability of the sensor are first described. Then the ability to...The ratio measurement by means of the sensing optical fiber and the reference fiber with different beginning positions, and the technique to improve the stability of the sensor are first described. Then the ability to restrain and compensate the interference of the same nature through the double channel ratio measurement is illustrated. Finally, the performance of sensor and its engineering design are discussed.展开更多
In this paper an optically-powered optical fiber sensor for pressure measurement is introduced.Differential strain gauges of diffused silicon are employed as sensing elements and a micro-power-consumption circuit is u...In this paper an optically-powered optical fiber sensor for pressure measurement is introduced.Differential strain gauges of diffused silicon are employed as sensing elements and a micro-power-consumption circuit is used in the probe.Pulse width modulation and pulse position modulation are adopted for signal processing.展开更多
Non-destructive measurement of absolute stress in steel members can provide useful information to optimize the design of steel structures and allow the safety of existing structures to be evaluated.This paper investig...Non-destructive measurement of absolute stress in steel members can provide useful information to optimize the design of steel structures and allow the safety of existing structures to be evaluated.This paper investigates the non-destructive capability of ultrasonic shear-wave spectroscopy in absolute stress evaluation of steel members.The effect of steel-member stress on the shear-wave amplitude spectrum is investigated,and a method of absolute stress measurement is proposed.Specifically,the process for evaluating absolute stress using shear-wave spectroscopy is summarized.Two steel members are employed to investigate the relationship between the stress and the frequency in shear-wave echo amplitude spectrum.The H-beam loaded by the universal testing machine is evaluated by the proposed method and the traditional strain gauge method for verification.The results show that the proposed method is effective and accurate for determining absolute stress in steel members.展开更多
Transient photovoltage of ITO/organic/Al cells is studied under different bias polarities and voltages.It is found that for an ITO/NPB/Al cell,light incidence on the Al side induces more bias-dependent transient photo...Transient photovoltage of ITO/organic/Al cells is studied under different bias polarities and voltages.It is found that for an ITO/NPB/Al cell,light incidence on the Al side induces more bias-dependent transient photovoltage variation when the photovoltage is positive than when it is negative.However,for an ITO/C60 /Al cell,the variation characteristics of transient photovoltage is reversed.These results support the previously proposed mechanism that Al could inject charges into the organic layer upon photon excitation,indicating that the absorption of electrode can also contribute to photovoltaic effect.展开更多
In this work, the theoretical model of FBG when it is affected by double external variables (temperature and transverse pressure) and triple external variables (temperature, axial strain and transverse pressure) is de...In this work, the theoretical model of FBG when it is affected by double external variables (temperature and transverse pressure) and triple external variables (temperature, axial strain and transverse pressure) is deduced, respectively. The simulated results show that the properties of cross sensitivity would change in a certain regulation with the external effects and fiber parameters. At the same time, some valuable suggestions about how to improve the measurement accuracy are put forward as well.展开更多
文摘We investigate the squeezing properties of the cavity field in the degenerate two-photon Jaynes Cummings model. Compared with the one-photon Jaynes-Cummings model, the squeezing is more pronounced in the case of two-photon Jaynes-Cummings model under certain conditions.
文摘As one of the interesting optical techniques for measurements of the velocity,the spatial filtering method is treated briefly in this paper.We shown theoretical analysis and calculation of spatial filtering velocimetry,and discussed two-dimensional measurements of the velocity.About the data processing,we used A/D conversion and interfaced with a microcomputer,so that the data can be processed automatically by the microcomputer.The preliminary experiment was performed and the experimental results show the usefulness of the present method for measurements of the velocity.
文摘The system principle and configuration of the double differential pressure method for measuring oil tank level are presented. The fundamental method and circuit of fiber optic transmission are analyzed .The accuracy and security of level measurement in the oil tanks have been greatly improved.
文摘Objective To evaluate the variations of intraocular pressure （lOP） in suspected open-angle glaucoma （OAG） patients. Methods The variations of lOP were measured in 216 eyes of suspected OAG patients at 4-hour intervals for 48 h. Based on the results of the serial lOP measurements, optic disc changed and visual field defected, the patients were diagnosed as primary OAG （ POAG ）, normal tension glaucoma （NTG）, ocular hypertension （ OHT） , or physiologic cup （PC）. Results After the serial lOP measurements, 16. 7% of the suspected OAG patients were diagnosed as POAG, 32. 4% as NTG, 24. 5% as OHT, and 26. 4% as PC. The highest percentages of the POAG group had peak lOP at 8 AM （19. 4% ） and their trough lOP at 10 PM （27. 8% ） ; the NTG group had peak lOP at 12 AM （18. 6% ） and their trough lOP at 12 PM （22. 9% ） ; the OHT group had peak lOP at 4 AM （22. 6% ） and their trough lOP at 10 PM （26. 4% ） ; and the PC group had peak lOP at 4 AM （ 21. 1% ） and their trough lOP at 12 PM （ 21. 1% ）. The percentages of peak lOP outside clinic （ 8 AM - 4 PM） in the POAG, NTG, OHT and PC groups were 55. 6%, 50. 0%, 58. 4% and 45. 7%, respectively. The mean magnitude of variance was 5. 1 - 6. 7 mmHg in those suspected OAG patients. There was a strong positive correlation in lOP between both eyes at each time point of measurement and the variation curves of the right and left eyes had parallel profiles in those suspected OAG patients. Conclusion Serial measurement of lOP is still needed, in order not to miss the peak and the trough lOP readings in suspected OAG patients, which helps in better management of glaucoma.
文摘The ratio measurement by means of the sensing optical fiber and the reference fiber with different beginning positions, and the technique to improve the stability of the sensor are first described. Then the ability to restrain and compensate the interference of the same nature through the double channel ratio measurement is illustrated. Finally, the performance of sensor and its engineering design are discussed.
文摘In this paper an optically-powered optical fiber sensor for pressure measurement is introduced.Differential strain gauges of diffused silicon are employed as sensing elements and a micro-power-consumption circuit is used in the probe.Pulse width modulation and pulse position modulation are adopted for signal processing.
基金supported by the National Key Research and Development Program of China (No. 2016YFC0701102)the National Nature Science Foundation of China(No.51538003)the Shenzhen Technology Innovation Program (No.JSGG20150330103937411)
文摘Non-destructive measurement of absolute stress in steel members can provide useful information to optimize the design of steel structures and allow the safety of existing structures to be evaluated.This paper investigates the non-destructive capability of ultrasonic shear-wave spectroscopy in absolute stress evaluation of steel members.The effect of steel-member stress on the shear-wave amplitude spectrum is investigated,and a method of absolute stress measurement is proposed.Specifically,the process for evaluating absolute stress using shear-wave spectroscopy is summarized.Two steel members are employed to investigate the relationship between the stress and the frequency in shear-wave echo amplitude spectrum.The H-beam loaded by the universal testing machine is evaluated by the proposed method and the traditional strain gauge method for verification.The results show that the proposed method is effective and accurate for determining absolute stress in steel members.
基金supported by the Ministry of Science and Technology of Chinathe National Natural Science Foundation of ChinaShanghai Science and Technology Committee
文摘Transient photovoltage of ITO/organic/Al cells is studied under different bias polarities and voltages.It is found that for an ITO/NPB/Al cell,light incidence on the Al side induces more bias-dependent transient photovoltage variation when the photovoltage is positive than when it is negative.However,for an ITO/C60 /Al cell,the variation characteristics of transient photovoltage is reversed.These results support the previously proposed mechanism that Al could inject charges into the organic layer upon photon excitation,indicating that the absorption of electrode can also contribute to photovoltaic effect.
基金supported by the National Natural Science Foundation of China (No.50876120)the Natural Science Foundation Project of Chongqing, China (No.2010BB2298)
文摘In this work, the theoretical model of FBG when it is affected by double external variables (temperature and transverse pressure) and triple external variables (temperature, axial strain and transverse pressure) is deduced, respectively. The simulated results show that the properties of cross sensitivity would change in a certain regulation with the external effects and fiber parameters. At the same time, some valuable suggestions about how to improve the measurement accuracy are put forward as well.
