Abstract:To address the challenges long prevalent in aircraft development strength testing—such as sequential execution, information silos, inefficient collaboration, and delayed validation—this paper proposes a digital parallel collaboration architecture oriented toward the entire lifecycle structural strength test of aircraft, reengineering the organizational models, process systems, and technical methodologies of strength testing. Centered on the core principles of "digital model-driven testing, end-to-end process integration, parallelized operations, interconnected design, and closed-loop optimization,". It introduces a "Three-Dimensional Coordinate System Architecture" (Aircraft Development Lifecycle x All Test Elements x Digital Approaches), enabling three-dimensional integration of development phases, test activities, and digital capabilities. By defining eight development stages, five core test activities, and six digital methodologies, a "1+5" procedural document system is established, complemented by maturity management, product data management, and a collaborative platform. An engineering case study validates the practicability of the parallel-collaborative architecture. The architecture developed in this study can be extended to other types of strength tests, providing a replicable engineering model for the digital parallel collaboration of aerospace structural testing across the full life cycle.

Abstract:A polarization-ratio control device based on the selective Bragg reflection of cholesteric liquid crystal (CLC) was designed for single-beam spin-exchange relaxation-free (SERF) atomic magnetometers, in which the same optical beam is used for both atomic pumping and magneto-optical detection, while conventional polarization-control optics hinder system miniaturization. An ellipticity angle of 22.5° was selected as the target operating point, corresponding to a required power ratio of 5.83:1 between the left- and right-handed circularly polarized components. This polarization requirement was converted into structural parameters of the CLC device, and a two-dimensional frequency-domain model was established in COMSOL Multiphysics for numerical simulation. The results show that, at an operating wavelength of 795 nm, the designed CLC pitch is approximately 497 nm. When the effective thickness is approximately 4.34 pitches, the reflectance of the target-handed circularly polarized component reaches approximately 82.84%, whereas the orthogonally handed component maintains a low reflectance, enabling effective control of the transmitted circular-polarization power ratio. A CLC sample was subsequently fabricated and characterized experimentally. The transmitted beam retained an approximately Gaussian spatial intensity distribution. Under small variations in the angle of incidence, the relative variations in both transmitted power and ellipticity remained within approximately 0.5%. During a 30-min continuous measurement, the transmitted power remained stable at approximately 3.68 mW, with an overall fluctuation of less than 1.72%. The experimental results demonstrate that the proposed CLC device can achieve elliptical-polarization ratio control through finite selective reflection, providing a potential approach for the miniaturization and integration of polarization-control optics in single-beam atomic magnetometers. Key words: atomic magnetometer; cholesteric liquid crystal; selective Bragg reflection; elliptical polarization; polarization ratio; polarization control;COMSOL Multiphysics software; optical-path integration

Abstract:This paper reviews the physical principles and information-theoretic description of ghost imaging, an imaging technique based on the high-order statistical correlation of optical fields. First, the physical principles of ghost imaging are introduced: the fundamental concepts of optical field correlation functions and first- and second-order coherence are expounded, and the high-order statistical correlation characteristics of typical light sources, including coherent states, thermal (pseudo-thermal) light, and entangled photon pairs, are analyzed. The imaging mechanism in which the degree of second-order coherence of the optical field exhibits a single-peaked distribution under both entangled photon-pair and (pseudo-)thermal light illumination, thereby establishing a point-to-point mapping between the object plane and the image plane, is discussed, together with the unified interpretation offered by the Klyshko equivalent optical path. Subsequently, from the information-theoretic perspective, the ghost imaging process is modeled as the transmission of information in a “source–channel–sink” model: the applicable conditions and internal relations of classical information metrics, including mutual information, channel capacity, Fisher information, and the Cramér–Rao bound, in imaging performance evaluation are analyzed; the encoding optimization and decoding optimization approaches guided by information metrics are classified, compared, and reviewed; and the applicable conditions and feasible paths for introducing quantum information-theoretic tools such as quantum mutual information and quantum Fisher information are explored. It is pointed out that the statistical structure of the second-order correlation function of the optical field determines the information acquisition capability of the imaging system, and that information metrics are evolving from “post-hoc evaluation” toward “a priori design”. It is concluded that mutual information, channel capacity, and Fisher information characterize imaging performance in terms of information acquisition efficiency, channel transmission potential, and parameter estimation precision, respectively, and are mutually complementary. It is proposed that future research be deepened in directions such as the collaborative design of encoding and decoding optimization, the quantitative comparison between the performance of decoding algorithms and information-theoretic limits, quantum channel modeling for ghost imaging with non-classical light sources, and applications oriented toward weak signals and special bands, so as to further reveal the mechanisms of information transfer in the ghost imaging process, enhance the information transmission efficiency and image reconstruction accuracy of imaging systems, and promote the application and development of related technologies in biomedical imaging, radar detection, and other fields.

Abstract:The dynamics of the interconnected electron–nuclear spin system affect the response bandwidth of atomic-spin inertial measurement and its ability to reject external magnetic-field interference and are important for performance evaluation and operating-parameter selection. An axial steady-state operating point is obtained from the full six-dimensional nonlinear Bloch model under spin-exchange relaxation-free (SERF) conditions. A local transverse model in complex variables is derived and checked against the numerical Jacobian and small-perturbation time-domain responses. With the operating point, diagonal dynamics, and input vectors fixed, off-diagonal coupling terms are set to zero or continuously scaled to compare changes in the transverse poles and the inertial and magnetic-field responses. At a rotation-step amplitude of 0.0125 rad/s, the normalized root-mean-square error between the outputs of the two models is 0.00686%. In the reference case with bidirectional coupling, the transverse slow-pole decay rate increases from 0.25 s?1 to 37.91 s?1. The contribution of slow nuclear-spin dynamics to the electron-spin output extends the settling time from 0.0191 s to 0.1541 s. When both off-diagonal coupling coefficients are increased by 30%, the inertial response bandwidth increases from 4.18 Hz to 8.34 Hz. Modal decomposition shows that the fast- and slow-mode contributions to the magnetic-field dc gain nearly cancel in the reference case, while their different time evolutions can still produce a transient peak. The magnitude and complex phase of the coupling product jointly affect the transverse poles, whereas the measurement response also depends on modal input excitation and output projection. These results apply to small perturbations near the specified operating point and the local coupling-term variations examined. The findings provide a theoretical reference for system parameter design that considers both inertial response bandwidth and magnetic-field rejection.

Abstract:Nuclear Magnetic Resonance Gyroscopes (NMRGs) exhibit significant potential for miniaturization and high-precision, positioning them as a critical technology path for next-generation micro-gyroscopes. To support the development of micro?NMRGs, this study fabricated a fully glass?based Rb–Xe vapor cell with an internal dimension of 1 mm×1 mm×1 mm via optical bonding, and systematically measured key parameters of the nuclear spin ensemble. Results at 130 ℃ showed longitudinal relaxation time (T1), transverse relaxation time (T2), and polarization fields were 7.382 s, 3.316 s, and 11.382 nT for 129Xe, respectively, and those for 131Xe were 15.381 s, 9.029 s, and 20.344 nT, respectively. These parameters as a function of temperature in the range of 115 ℃-140 ℃ were also obtained. Based on the measured parameters, the angular random walk (ARW) for the NMRG employing this cell is estimated to be 0.17?°/√h. A key challenge remains further increasing the relaxation times. This research on miniature vapor cell provides a foundational basis for advancing micro-NMRGs development.