利用1989—1996年滇西地震预报实验场绝对重力和相对重力观测资料,采用逐年差分和多年累积的方法,分析滇西地震预报实验场内部不同时间尺度的重力场演变特征及其与丽江地震在时空上的对应关系,结果表明:①1992年以前,研究区内部重力场...利用1989—1996年滇西地震预报实验场绝对重力和相对重力观测资料,采用逐年差分和多年累积的方法,分析滇西地震预报实验场内部不同时间尺度的重力场演变特征及其与丽江地震在时空上的对应关系,结果表明:①1992年以前,研究区内部重力场变化平稳,1993年出现局部变化,1995年变化急剧加大,震后快速反向调整,变化量值基本与震前多年累积相当,重力场演化特征与丽江地震存在高度时空对应关系,表明该时段重力场变化为丽江地震的孕震特征。②研究区差分及累积重力场动态演化过程中,在川滇菱形块体与滇西块体边界产生重力变化梯度带,表明这2个块体构造活动剧烈。③沿红河断裂带出现(-60~90)×10-8 m/s 2的重力变化高梯度带,其走向与红河断裂构造高度一致,反映区域重力场变化受主要活动构造控制,是地下深部壳幔物质运移的表现。展开更多
A 16-channel arrayed waveguide grating(AWG)with an 800 GHz channel spacing in the O-band has been developed and fabricated based on silica planar lightwave circuit(PLC)technology.By extending the wave⁃length allocatio...A 16-channel arrayed waveguide grating(AWG)with an 800 GHz channel spacing in the O-band has been developed and fabricated based on silica planar lightwave circuit(PLC)technology.By extending the wave⁃length allocation from 8 channels to 16 channels as specified in IEEE 802.3bs,we increased the number of chan⁃nels and boosted transmission capacity to meet the 1.6 Tbps and higher-speed signal transmission requirements for future data centers.Through optimizing the AWG structure,it has achieved insertion loss(IL)better than-1.61 dB,loss uniformity below 0.35 dB,polarization-dependent loss(PDL)below 0.35 dB,adjacent channel cross⁃talk under-20.05 dB,ripple less than 0.75 dB,center wavelength offset under 0.22 nm and 1 dB bandwidth ex⁃ceeding 2.88 nm.The AWG has been successfully measured to transmit 53 Gbaud 4-level pulse amplitude modu⁃lation(PAM4)signal per channel and the total transmission speed can reach over 1.6 Tbps.展开更多
This study systematically analyzed the spatiotemporal evolution characteristics of geomagnetic anomalies before and after the 2013 Sichuan Lushan M7.0 earthquake and the Gansu Minxian M6.6 earthquake by constructing a...This study systematically analyzed the spatiotemporal evolution characteristics of geomagnetic anomalies before and after the 2013 Sichuan Lushan M7.0 earthquake and the Gansu Minxian M6.6 earthquake by constructing a geomagnetic diurnal variation model based on Taylor polynomial fitting,combined with midnight mean values of the geomagnetic F component from China,s geomagnetic observatory network.The results reveal distinct differences in anomaly patterns,namely per-sistent positive anomalies were observed in the epicentral region of the Lushan earthquake,while significant negative anomalies characterized the Minxian earthquake zone.This differential response reveals the modulating effect of the electrical structure of the seismogenic medium on space electromagnetic disturbances,namely positive anomalies may correspond to the stage of stable stress accumulation in intact rock,while the expansion of negative anomalies may reflect an amplification of electromagnetic disturbances induced by fracture expansion.Further analysis demonstrates that both anomalies exhibit a three-stage evolutionary pattern,namely pre-seismic accumulation,co-seismic release,and post-seismic adjustment.The phase transitions in these anomalies are closely correlated with regional tectonic stress accumulation and destabilization processes.These findings not only provide new evidence for the physical interpretation of seismomagnetic precursors but also establish a theoretical foundation for developing earthquake prediction methods based on the dynamic evolution of geomagnetic anomalies.展开更多
Planar lightwave circuit(PLC)splitters have long been foundational components in passive optical communication networks,achieving commercial success since the 1990s.However,their inherent fixed splitting ratios impose...Planar lightwave circuit(PLC)splitters have long been foundational components in passive optical communication networks,achieving commercial success since the 1990s.However,their inherent fixed splitting ratios impose significant limitations on capacity expansion,often requiring physical replacement and causing service disruptions.Thermally tunable optical splitters address this challenge by enabling adjustable splitting ratios,but their operation is contingent upon a continuous power supply and complex driving systems.In this work,we present a novel,non-volatile tunable PLC platform based on Sb_(2)S_(3)phase-change materials.The proposed device,which incor-porates a Mach-Zehnder interferometer(MZI)optical switch structure,offers tunable splitting ratios via laser-direct writing or ohmic heating,providing flexible reconfiguration capabilities.Experimental results demonstrate non-volatile power splitting ranging from 50∶50 to 20∶80,with a modest increase of approximately 1 dB in additional loss.This work highlights the potential of the proposed platform for low-power,high-efficiency,and reconfigurable photonic networks.展开更多
文摘利用1989—1996年滇西地震预报实验场绝对重力和相对重力观测资料,采用逐年差分和多年累积的方法,分析滇西地震预报实验场内部不同时间尺度的重力场演变特征及其与丽江地震在时空上的对应关系,结果表明:①1992年以前,研究区内部重力场变化平稳,1993年出现局部变化,1995年变化急剧加大,震后快速反向调整,变化量值基本与震前多年累积相当,重力场演化特征与丽江地震存在高度时空对应关系,表明该时段重力场变化为丽江地震的孕震特征。②研究区差分及累积重力场动态演化过程中,在川滇菱形块体与滇西块体边界产生重力变化梯度带,表明这2个块体构造活动剧烈。③沿红河断裂带出现(-60~90)×10-8 m/s 2的重力变化高梯度带,其走向与红河断裂构造高度一致,反映区域重力场变化受主要活动构造控制,是地下深部壳幔物质运移的表现。
基金Supported by the National Key Research and Development Program of China(2021YFB2800201)the Strategic Priority Research Program of Chinese Academy of Sciences(XDB43000000)。
文摘A 16-channel arrayed waveguide grating(AWG)with an 800 GHz channel spacing in the O-band has been developed and fabricated based on silica planar lightwave circuit(PLC)technology.By extending the wave⁃length allocation from 8 channels to 16 channels as specified in IEEE 802.3bs,we increased the number of chan⁃nels and boosted transmission capacity to meet the 1.6 Tbps and higher-speed signal transmission requirements for future data centers.Through optimizing the AWG structure,it has achieved insertion loss(IL)better than-1.61 dB,loss uniformity below 0.35 dB,polarization-dependent loss(PDL)below 0.35 dB,adjacent channel cross⁃talk under-20.05 dB,ripple less than 0.75 dB,center wavelength offset under 0.22 nm and 1 dB bandwidth ex⁃ceeding 2.88 nm.The AWG has been successfully measured to transmit 53 Gbaud 4-level pulse amplitude modu⁃lation(PAM4)signal per channel and the total transmission speed can reach over 1.6 Tbps.
基金supported by a Collaborative Project of the National Natural Science Foundation of China on Technical Maintenance and Data Preprocessing of the GPS Observation Array for the Qiaojia Earthquake(No.0120603)the National Natural Science Foundation of China(No.41274079).
文摘This study systematically analyzed the spatiotemporal evolution characteristics of geomagnetic anomalies before and after the 2013 Sichuan Lushan M7.0 earthquake and the Gansu Minxian M6.6 earthquake by constructing a geomagnetic diurnal variation model based on Taylor polynomial fitting,combined with midnight mean values of the geomagnetic F component from China,s geomagnetic observatory network.The results reveal distinct differences in anomaly patterns,namely per-sistent positive anomalies were observed in the epicentral region of the Lushan earthquake,while significant negative anomalies characterized the Minxian earthquake zone.This differential response reveals the modulating effect of the electrical structure of the seismogenic medium on space electromagnetic disturbances,namely positive anomalies may correspond to the stage of stable stress accumulation in intact rock,while the expansion of negative anomalies may reflect an amplification of electromagnetic disturbances induced by fracture expansion.Further analysis demonstrates that both anomalies exhibit a three-stage evolutionary pattern,namely pre-seismic accumulation,co-seismic release,and post-seismic adjustment.The phase transitions in these anomalies are closely correlated with regional tectonic stress accumulation and destabilization processes.These findings not only provide new evidence for the physical interpretation of seismomagnetic precursors but also establish a theoretical foundation for developing earthquake prediction methods based on the dynamic evolution of geomagnetic anomalies.
基金sponsored by the National Key Research and Development Program of China(2020YFA0714504,2019YFA0709100)the program of the National Natural Science Foundation of China(U24A20309,62305043).
文摘Planar lightwave circuit(PLC)splitters have long been foundational components in passive optical communication networks,achieving commercial success since the 1990s.However,their inherent fixed splitting ratios impose significant limitations on capacity expansion,often requiring physical replacement and causing service disruptions.Thermally tunable optical splitters address this challenge by enabling adjustable splitting ratios,but their operation is contingent upon a continuous power supply and complex driving systems.In this work,we present a novel,non-volatile tunable PLC platform based on Sb_(2)S_(3)phase-change materials.The proposed device,which incor-porates a Mach-Zehnder interferometer(MZI)optical switch structure,offers tunable splitting ratios via laser-direct writing or ohmic heating,providing flexible reconfiguration capabilities.Experimental results demonstrate non-volatile power splitting ranging from 50∶50 to 20∶80,with a modest increase of approximately 1 dB in additional loss.This work highlights the potential of the proposed platform for low-power,high-efficiency,and reconfigurable photonic networks.
