In this work,a new structure is used to enhance the nonlinear effect in the cavity,which improvesthe performance of the 1.3μm broadband swept source.The swept source adopts a semiconductoroptical amplifier(SOA),a cir...In this work,a new structure is used to enhance the nonlinear effect in the cavity,which improvesthe performance of the 1.3μm broadband swept source.The swept source adopts a semiconductoroptical amplifier(SOA),a circulator,a coupler,and a tunable filter.In the structure,the lightpasses through the nonlinear medium(SOA)twice in two opposite directions,which excites thenonlinear ffect and increases the performance of the swept source.The tunable filter is based on apolygon rotating mirror and gratings.Traditionally,multiple SOAs are adopted to improve thesweep range and the optical power,which increases the cost and complexity of the swept source.The method proposed in this paper can improve the spectral range and optical power of the sweptsources without additional accessories.For the short-cavity swept source,the power increasesfrom 6 mW to 7.7 mW,and the sweep range increases from 98 nm to 120 nm.The broadband swept sources could have wide applications in biomedical imaging,sensor system,measurementand so on.展开更多
The aim of this paper is to solve the problems that the existing method of critical production of gas cap reservoir is only suitable for single-phase flow, and the method of critical production of gas cap reservoir un...The aim of this paper is to solve the problems that the existing method of critical production of gas cap reservoir is only suitable for single-phase flow, and the method of critical production of gas cap reservoir under water-flooding is still blank. In this paper, the relationships between dynamic and static equilibrium, plane radial flow theory, oil-water infiltration method and three-dimensional seepage field decomposition theory, were applied to study a calculation method for critical production of directional wells and horizontal wells. Furthermore, the effects of different factors on critical output were studied, such as horizontal permeability, ratio of horizontal permeability to vertical permeability, length of horizontal section, effective thickness, viscosity of crude oil and water content etc. Results show that the critical production increases with the increment of the horizontal permeability, the ratio of the vertical permeability to the horizontal permeability, the reservoir thickness and the horizontal well length;when the viscosity of crude oil is small, the critical production decreases first and then increases with the increase of water content;when the viscosity of crude oil is high, the critical production increases continuously with the increase of water content. This study could provide theoretical and technical guidance for changing of the working system of oil wells. It can avoid gas channeling and improve the development effect.展开更多
波长快速扫描系统在算力网络、5G前传网络以及新一代可重构光分插复用系统等领域起着重要作用,整个波长扫描测试系统的性能基本取决于激光器性能的优劣。为此,基于In Ga As P/In P增益芯片优异的宽光谱光学特性和Littman-Metcalf外腔反...波长快速扫描系统在算力网络、5G前传网络以及新一代可重构光分插复用系统等领域起着重要作用,整个波长扫描测试系统的性能基本取决于激光器性能的优劣。为此,基于In Ga As P/In P增益芯片优异的宽光谱光学特性和Littman-Metcalf外腔反馈原理研制了一台具备宽调谐范围、高扫描速度以及无模式跳变等特点的可调谐激光器。实验上获得了240 nm/s的最高扫描速度、0.001 nm的最小步进触发间隔、优于±1.3 pm/1 min的波长稳定性、优于2.39 pm的绝对波长精度、优于±0.02 d B/1 min的功率稳定性及无跳模范围为110 nm的单纵模扫频输出。该研究有助于推动波长快速扫描测试系统的研究进程,提升波分复用等器件的测试精度和效率。展开更多
AIM： To categorize neovessels morphology and to detect response to anti-angiogenic therapy by using structural and angiographic modes of swept source optical coherence tomography（SS-OCT）.METHODS： Thirty-two eyes w...AIM： To categorize neovessels morphology and to detect response to anti-angiogenic therapy by using structural and angiographic modes of swept source optical coherence tomography（SS-OCT）.METHODS： Thirty-two eyes with neovessels at disc（NVD） and neovessels elsewhere（NVE）-as diagnosed by fluorescein angiography-were included. Cross sectional OCT images of disc and macular regions were registered to enface OCT angiography（OCTA）, B-scan blood flow over lay and density maps. Three eyes received antiangiogenic treatment.RESULTS： Pin point registration of cross-sectional OCT and OCTA images differentiated active NVD with vascular elements from fibrous or equivalent fibrovascular elements. En face images delineated NVE as vascular tufts or area of filling while cross-sectional images differentiated NVE from microvascular intraretinal abnormality（IRMA）. All cases were associated with enlargement of foveal avascular zone and or areas of capillary non perfusion. Regressed NVD appeared as ghost vessel or pruned vascular loops after injection.CONCLUSION： Structural and angiographic modes of SS-OCT can detect, characterize and categorize the pattern of wide spectrum of neovessels based on blood flow data and density maps. It is potentially useful to detect ischemic changes in the vascular bed and regression of NVD after therapeutic regimens providing substitute for invasive techniques.展开更多
基金supported by the National Key R&D Program of China(2016YFF0102003 and 2016YFF0102000).
文摘In this work,a new structure is used to enhance the nonlinear effect in the cavity,which improvesthe performance of the 1.3μm broadband swept source.The swept source adopts a semiconductoroptical amplifier(SOA),a circulator,a coupler,and a tunable filter.In the structure,the lightpasses through the nonlinear medium(SOA)twice in two opposite directions,which excites thenonlinear ffect and increases the performance of the swept source.The tunable filter is based on apolygon rotating mirror and gratings.Traditionally,multiple SOAs are adopted to improve thesweep range and the optical power,which increases the cost and complexity of the swept source.The method proposed in this paper can improve the spectral range and optical power of the sweptsources without additional accessories.For the short-cavity swept source,the power increasesfrom 6 mW to 7.7 mW,and the sweep range increases from 98 nm to 120 nm.The broadband swept sources could have wide applications in biomedical imaging,sensor system,measurementand so on.
文摘The aim of this paper is to solve the problems that the existing method of critical production of gas cap reservoir is only suitable for single-phase flow, and the method of critical production of gas cap reservoir under water-flooding is still blank. In this paper, the relationships between dynamic and static equilibrium, plane radial flow theory, oil-water infiltration method and three-dimensional seepage field decomposition theory, were applied to study a calculation method for critical production of directional wells and horizontal wells. Furthermore, the effects of different factors on critical output were studied, such as horizontal permeability, ratio of horizontal permeability to vertical permeability, length of horizontal section, effective thickness, viscosity of crude oil and water content etc. Results show that the critical production increases with the increment of the horizontal permeability, the ratio of the vertical permeability to the horizontal permeability, the reservoir thickness and the horizontal well length;when the viscosity of crude oil is small, the critical production decreases first and then increases with the increase of water content;when the viscosity of crude oil is high, the critical production increases continuously with the increase of water content. This study could provide theoretical and technical guidance for changing of the working system of oil wells. It can avoid gas channeling and improve the development effect.
文摘波长快速扫描系统在算力网络、5G前传网络以及新一代可重构光分插复用系统等领域起着重要作用,整个波长扫描测试系统的性能基本取决于激光器性能的优劣。为此,基于In Ga As P/In P增益芯片优异的宽光谱光学特性和Littman-Metcalf外腔反馈原理研制了一台具备宽调谐范围、高扫描速度以及无模式跳变等特点的可调谐激光器。实验上获得了240 nm/s的最高扫描速度、0.001 nm的最小步进触发间隔、优于±1.3 pm/1 min的波长稳定性、优于2.39 pm的绝对波长精度、优于±0.02 d B/1 min的功率稳定性及无跳模范围为110 nm的单纵模扫频输出。该研究有助于推动波长快速扫描测试系统的研究进程,提升波分复用等器件的测试精度和效率。
文摘AIM： To categorize neovessels morphology and to detect response to anti-angiogenic therapy by using structural and angiographic modes of swept source optical coherence tomography（SS-OCT）.METHODS： Thirty-two eyes with neovessels at disc（NVD） and neovessels elsewhere（NVE）-as diagnosed by fluorescein angiography-were included. Cross sectional OCT images of disc and macular regions were registered to enface OCT angiography（OCTA）, B-scan blood flow over lay and density maps. Three eyes received antiangiogenic treatment.RESULTS： Pin point registration of cross-sectional OCT and OCTA images differentiated active NVD with vascular elements from fibrous or equivalent fibrovascular elements. En face images delineated NVE as vascular tufts or area of filling while cross-sectional images differentiated NVE from microvascular intraretinal abnormality（IRMA）. All cases were associated with enlargement of foveal avascular zone and or areas of capillary non perfusion. Regressed NVD appeared as ghost vessel or pruned vascular loops after injection.CONCLUSION： Structural and angiographic modes of SS-OCT can detect, characterize and categorize the pattern of wide spectrum of neovessels based on blood flow data and density maps. It is potentially useful to detect ischemic changes in the vascular bed and regression of NVD after therapeutic regimens providing substitute for invasive techniques.
