A novel online Differential Mode Group Delay(DMGD)monitoring method based on four-wave mixing(FWM) in few mode fiber(FMF) transmission system is proposed, and the DMGD monitoring is achieved on the whole range of 15-5...A novel online Differential Mode Group Delay(DMGD)monitoring method based on four-wave mixing(FWM) in few mode fiber(FMF) transmission system is proposed, and the DMGD monitoring is achieved on the whole range of 15-50 ps/km. Detection principle is deduced and relationship of the power of idler waves and DMGD is analyzed. With various chromatic dispersion(CD)values, different line widths and different optical signal noise ratio(OSNR) values, the simulations are carried out. The simulation results show that this new DMGD monitoring method is less affected by different line widths and has a high tolerance for OSNR.展开更多
It is common that airlines encounter a disruption of a flight schedule,which is mainly caused by resource shortages.In case of a disruption,subject to scarce resources,most of airlines lose flexibility of performing a...It is common that airlines encounter a disruption of a flight schedule,which is mainly caused by resource shortages.In case of a disruption,subject to scarce resources,most of airlines lose flexibility of performing aircraft recovery on the basis of business interest priorities and need to delay,swap,and cancel flights.This paper proposes an air-rail inter-modal strategy to incorporate a High-Speed Rail(HSR)transport mode into an aviation network for aircraft recovery.The air-rail inter-modal strategy focuses on occasionally operational integration of existing airside and HSR infrastructure capacities.It is different from air-rail cooperation implemented in Europe which emphasizes a long-term strategy.In addition to modelling the air-rail inter-modal strategy,an inter-modal time-band network is presented.Modelling is applied to a pure aviation network and the inter-modal network.Comparison results show that the inter-modal air-rail strategy helps to reduce the number of cancelled flights and the total disruption cost.展开更多
Introduction: To investigate the inter-observer and inter-modality variabilities of two imaging guided equipments—cone-beam computed tomography (CBCT) and ultrasound (US) in kidney stereotactic body radiotherapy. Met...Introduction: To investigate the inter-observer and inter-modality variabilities of two imaging guided equipments—cone-beam computed tomography (CBCT) and ultrasound (US) in kidney stereotactic body radiotherapy. Methods: A renal metastasis case implanted with three gold anchor fiducial markers was firstly scanned by US to acquire a 3-dimension US image and followed by 4-dimension CBCT in every fraction. Seven observers retrospectively registered the pre-treatment images with the corresponding reference images based on the gold markers. Registration uncertainty of the observers between two imaging modalities was evaluated. Results: The uncertainties over whole treatment course in CBCT were 0.88 mm, 1.94 mm and 0.86 mm in lateral, longitudinal and vertical directions respectively;while 0.8 mm, 0.97 mm and 1.36 mm were found in US. Conclusion: The greatest uncertainty was found in longitudinal direction in CBCT due to the fact that the respiration motion is the most rigorous in cranial-caudal direction. In US, since the probe was hold almost in upright position, the strong echo in vertical direction was attributed to the greatest uncertainty for such direction.展开更多
为了提升光纤的传输性能,设计了一种空气孔-沟槽辅助六芯光纤结构。六芯光纤中每根纤芯被一层低折射率沟槽包围,纤芯与沟槽之间存在一层包层,同时光纤周围环绕着空气孔辅助结构。基于光纤的耦合模式理论,对光纤的串扰、模场面积以及弯...为了提升光纤的传输性能,设计了一种空气孔-沟槽辅助六芯光纤结构。六芯光纤中每根纤芯被一层低折射率沟槽包围,纤芯与沟槽之间存在一层包层,同时光纤周围环绕着空气孔辅助结构。基于光纤的耦合模式理论,对光纤的串扰、模场面积以及弯曲损耗3种传输特性进行了深入分析。研究结果表明:带有空气孔-沟槽辅助结构的光纤在芯间串扰方面表现最佳,串扰值达到最低约-55 d B;而单沟槽辅助结构则有效增大了光纤的模场面积,达到最大值约390μm^(2)。然而,不同结构下光纤的弯曲损耗变化并未呈现明显规律,但其对数取值集中在4~9 d B/m。展开更多
基金supported by the National Science Foundation of China (61574080)Research Center of Optical Communications Engineering & Technology,Jiangsu Province (ZXF201803)
文摘A novel online Differential Mode Group Delay(DMGD)monitoring method based on four-wave mixing(FWM) in few mode fiber(FMF) transmission system is proposed, and the DMGD monitoring is achieved on the whole range of 15-50 ps/km. Detection principle is deduced and relationship of the power of idler waves and DMGD is analyzed. With various chromatic dispersion(CD)values, different line widths and different optical signal noise ratio(OSNR) values, the simulations are carried out. The simulation results show that this new DMGD monitoring method is less affected by different line widths and has a high tolerance for OSNR.
基金co-supported by the Tianjin Natural Science Foundation, China (No. 18JCQNJC04300)the National Natural Science Foundation of China (No. 71801215)the Foundation for University Key Teacher by the Ministry of Education of China (Nos. 3122018C033, 3122015L010)
文摘It is common that airlines encounter a disruption of a flight schedule,which is mainly caused by resource shortages.In case of a disruption,subject to scarce resources,most of airlines lose flexibility of performing aircraft recovery on the basis of business interest priorities and need to delay,swap,and cancel flights.This paper proposes an air-rail inter-modal strategy to incorporate a High-Speed Rail(HSR)transport mode into an aviation network for aircraft recovery.The air-rail inter-modal strategy focuses on occasionally operational integration of existing airside and HSR infrastructure capacities.It is different from air-rail cooperation implemented in Europe which emphasizes a long-term strategy.In addition to modelling the air-rail inter-modal strategy,an inter-modal time-band network is presented.Modelling is applied to a pure aviation network and the inter-modal network.Comparison results show that the inter-modal air-rail strategy helps to reduce the number of cancelled flights and the total disruption cost.
文摘Introduction: To investigate the inter-observer and inter-modality variabilities of two imaging guided equipments—cone-beam computed tomography (CBCT) and ultrasound (US) in kidney stereotactic body radiotherapy. Methods: A renal metastasis case implanted with three gold anchor fiducial markers was firstly scanned by US to acquire a 3-dimension US image and followed by 4-dimension CBCT in every fraction. Seven observers retrospectively registered the pre-treatment images with the corresponding reference images based on the gold markers. Registration uncertainty of the observers between two imaging modalities was evaluated. Results: The uncertainties over whole treatment course in CBCT were 0.88 mm, 1.94 mm and 0.86 mm in lateral, longitudinal and vertical directions respectively;while 0.8 mm, 0.97 mm and 1.36 mm were found in US. Conclusion: The greatest uncertainty was found in longitudinal direction in CBCT due to the fact that the respiration motion is the most rigorous in cranial-caudal direction. In US, since the probe was hold almost in upright position, the strong echo in vertical direction was attributed to the greatest uncertainty for such direction.
文摘为了提升光纤的传输性能,设计了一种空气孔-沟槽辅助六芯光纤结构。六芯光纤中每根纤芯被一层低折射率沟槽包围,纤芯与沟槽之间存在一层包层,同时光纤周围环绕着空气孔辅助结构。基于光纤的耦合模式理论,对光纤的串扰、模场面积以及弯曲损耗3种传输特性进行了深入分析。研究结果表明:带有空气孔-沟槽辅助结构的光纤在芯间串扰方面表现最佳,串扰值达到最低约-55 d B;而单沟槽辅助结构则有效增大了光纤的模场面积,达到最大值约390μm^(2)。然而,不同结构下光纤的弯曲损耗变化并未呈现明显规律,但其对数取值集中在4~9 d B/m。
