We first propose and experimentally demonstrate the engineered Raman-Kerr microcomb by adjusting the gains between Raman and Kerr effects in an integrated chalcogenide microresonator, leading to controllable approache...
详细信息
In this paper, the problem of model reduction for Takagi-Sugeno (T-S) fuzzy systems is studied. The virtual inner disturbance is first constructed to map a potential link between the states of two systems before and a...
详细信息
Gaofen-3-02(GF3-02)is the first C-band synthetic aperture radar(SAR)satellite with terrain observation with progressive scans of SAR(TOPSAR)imaging mode in China,which plays an essential role in marine environment ***...
详细信息
Gaofen-3-02(GF3-02)is the first C-band synthetic aperture radar(SAR)satellite with terrain observation with progressive scans of SAR(TOPSAR)imaging mode in China,which plays an essential role in marine environment *** the weak scattering characteristics of the ocean,the system thermal noise superimposed on SAR images has significant interference,especially in cross-polarization ***-Equivalent Sigma-Zero(NESZ)is a measure of the sensitivity of the radar to areas of low *** NESZ is defined to be the scattering cross-section coefficient of an area which contributes a mean level in the image equal to the signal-independent additive noise *** TOPSAR,NESZ exhibits the shape of the SAR scanning gain curve in the azimuth and the shape of the antenna pattern in the ***,the accurate measurement of NESZ plays a vital role in the application of spaceborne SAR sea surface cross-polarization *** paper proposes a theoretical calculation method for the NESZ curve in GF3-02 TOPSAR mode based on SAR noise inner calibration data and the imaging algorithm.A method for correcting the error existing in the theoretical curve of NESZ is also proposed according to the relationship between sea surface backscattering and wind speed and the same characteristics of target scattering in the overlapping area of adjacent *** to assessment with wide-swath TOPSAR cross-polarization data,the GF3-02 TOPSAR mode has a very low thermal noise level,which is better than−33 dB at the edge of each beam,and controlled below−38 dB at the center of the *** two-dimensional reference curves of the NESZ of each beam are provided to the GF3-02 TOPSAR *** discussing the relationship between normalized radar cross section(NRCS)and wind speed,we provide a formula for NRCS related to wind speed and radar incidence *** with the NRCS derived from this formula and the NESZ-subtracted NRCS of SAR images,the bias is−0.0048
We report an integrated GeSbS microring resonator with intrinsic quality factors of more than 5 million, first demonstrating a Brillouin laser with fundamental linewidth of 143 Hz and an o u t p u t p o w e r u p t o ...
详细信息
This paper studies the power switch open-circuit(OC) fault in two-level three-phase (2L3P) voltage source inverter (VSI). According to the topological symmetry of the inverter, when it works in healthy conditions, its...
详细信息
Accurate transverse displacement measurement at the picometer scale is essential for advancing ultraprecision metrology and probing microscopic physical interactions. Here, we demonstrate a high-precision transverse d...
详细信息
Accurate transverse displacement measurement at the picometer scale is essential for advancing ultraprecision metrology and probing microscopic physical interactions. Here, we demonstrate a high-precision transverse displacement sensor leveraging a phase-matched Pancharatnam–Berry (PB) metasurface and trapezoidal prism configuration, which simplifies optical alignment by eliminating stringent Talbot self-imaging requirements. By synergistically matching the phase gradient of the PB metasurface with the prism geometry, we enable robust signal extraction through the photonic spin Hall effect, while a near-infrared source ( λ = 1550 nm) suppresses environmental interference. Differential amplification further rejects common-mode noise from laser fluctuations and electronic drift. The system achieves a displacement resolution of 46.18 pm under quasi-static conditions (0.2–100 Hz) and 124.86 pm across the full operational bandwidth (0.2–1.25 MHz), surpassing conventional polarization-encoded schemes in both sensitivity and practicality. This work thus presents a strategy for metasurface-enhanced metrology via geometric-phase-engineered photonic architectures, with transformative potential across applications from semiconductor lithography to quantum optomechanics.
An equivalent definition of hypermatrices is *** matrix expression of hypermatrices is *** permu-tation matrices,the conversion between different matrix expressions is *** various kinds of contracted products of hyper...
详细信息
An equivalent definition of hypermatrices is *** matrix expression of hypermatrices is *** permu-tation matrices,the conversion between different matrix expressions is *** various kinds of contracted products of hypermatrices are realized by semi-tensor products(STP)of matrices via matrix expressions of hypermatrices.
RNA-binding proteins (RBPs) are essential for gene expression, and the complex RNA-protein interaction mechanisms require analysis of global RNA information. Therefore, accurate prediction of RBP binding sites on full...
详细信息
Orbital angular momentum (OAM)-based dense space-division multiplexing technology has emerged as a promising candidate to break through the Shannon limit of single-mode fibers. While optical coordinate transformation ...
详细信息
This work presents an adaptive tracking guidance method for robotic fishes. The scheme enables robots to suppress external interference and eliminate motion jitter. An adaptive integral surge line-of-sight guidance ru...
详细信息
This work presents an adaptive tracking guidance method for robotic fishes. The scheme enables robots to suppress external interference and eliminate motion jitter. An adaptive integral surge line-of-sight guidance rule is designed to eliminate dynamics interference and sideslip issues. Limited-time yaw and surge speed observers are reported to fit disturbance variables in the model. The approximation values can compensate for the system's control input and improve the robots' tracking ***, this work develops a terminal sliding mode controller and third-order differential processor to determine the rotational torque and reduce the robots' run jitter. Then, Lyapunov's theory proves the uniform ultimate boundedness of the proposed method. Simulation and physical experiments confirm that the technology improves the tracking error convergence speed and stability of robotic fishes.
暂无评论