Abstract:This paper summarizes the research progress of metrology and test technology for optical properties of materials, including internationally mutual recognized calibration and measurement capabilities, international comparisons, national metrology primary standard facilities, verification regulations and calibration specifications, and national standards. It introduces the methods, principles, capability, and uncertainties of primary standards such as spectral rule transmittance, spectral diffuse reflectance, and diffuse transmittance visual density measurement facilities, as well as social common standards such as wavelength in a continuous wide spectrum. It also summarizes the national standards on the test methods for the comprehensive optical, mechanical, thermal, and chemical properties of optical materials with colorless optical glass as an example. It concludes that the national metrology and test technology for optical properties of materials have been improved rapidly, with significant international and domestic influence, effectively ensuring the research and application of high?quality optical materials and high?precision material optical property measurement instruments, and promoting the high?quality development of the national optical material industry. With increasing demands for advanced optical materials in cutting?edge fields, it is very important to steadily enhance the technical infrastructure, continuously expand the measurement range, and deeply focus on the physical essences, to underpin the key metrology and test technology for optical properties of materials to further play a key role in the fields of precision measurement, efficient perception, digital reconstruction, intelligent decision?making, human?computer interaction and so on.

Abstract:This article introduces the principle of single?photon Light Detection and Ranging（LiDAR） system, elaborates on the composition and core device characteristics of single?photon LiDAR system, and discusses the advantages of single?photon LiDAR technology such as photon?level sensitivity and picosecond level time accuracy. From the perspectives of hardware improvement and algorithm improvement, optimization methods for single?photon LiDAR systems were analyzed. The applications of single?photon LiDAR technology in ground?based long?range target imaging, aerospace remote sensing, and complex scene imaging were explored, and the future development direction of single?photon LiDAR technology was prospected. It was pointed out that the detection efficiency, dark count rate, time jitter, and power consumption can be improved by expanding the detector response band, optimizing device design, and applying new materials; Advanced algorithms can be utilized to achieve deep information mining, and improve detection accuracy and real?time performance; Single?photon LiDAR technology can be combined with other advanced technologies to expand its application scope.

Abstract:In order to meet the calibration needs of large?size transient pressure probe rakes, a pressure probe rake calibration method based on expansion shock tube was proposed. The FLUENT software was used to simulate the dynamics of the shock wave in the shock tube, and the operation law of the shock wave and the change of pressure and density of the flow field were analyzed. The results showed that the pressure in the low?pressure section eventually became uniform after being affected by the incident shock wave, the reflected shock wave, the compression wave and its multiple reflections. The pressure measurement experiments were conducted by using the expansion shock tube device with soft and hard aluminum diaphragms. The results showed that the rise time was less than 9 ms and the duration of platform pressure was greater than 50 ms in the low?pressure section inside a 150 mm diameter of shock tube. This study has important reference value for the calibration of transient pressure testing systems in aero engine, aerospace, medical and other fields.

Abstract:In order to study the effects of femtosecond laser drilling and electrical discharge machining (EDM) drilling on high cycle fatigue life of nickel based single crystal turbine blade, finite element models for two drilling methods were established respectively. In the process of finite element calculation, combined with the constitutive characteristics of nickel based single crystal and the crystal plastic slip theory, the user defined material mechanical behavior (UMAT) of the single crystal constitutive model was written, and the shear stress distribution on each sliding surface of nickel based single crystal under high cycle fatigue boundary conditions was calculated. Based on the critical plane method, different damage criteria were established for the sliding system and sliding surface under specific stress state. The damage criteria of nickel based single crystal turbine blade suitable for femtosecond laser drilling and EDM drilling were selected, and the high cycle fatigue life prediction models were established respectively. The high cycle fatigue life of single crystal specimen and single crystal turbine blade with two drilling methods were predicted, and compared with the actual high cycle fatigue test results. The comparison error between the calculated life prediction results and the experimental life was about 10%. The research results provide a reference for optimizing the processing technology of aeroengine turbine blades.

Abstract:To tackle the challenges of miniaturization and enhanced application reliability in ⁸⁷Rb atom interferometers, an integrated optical system has been devised. Adopting the philosophy of modular design, the system is divided into three modules: fiber laser, spatial optical path and frequency stabilization, for easy installation and adjustment. By employing self?developed miniaturized optical components and optimizing the design of the spatial optical path and fiber laser, a substantial reduction in the size of the spatial optical path has been achieved, only with dimensions of 120 mm × 190 mm × 26 mm and a weight of 900 g. The optical path of frequency stabilization just has dimensions of 50 mm × 70 mm × 40 mm. All optical elements are securely fixed onto the optical baseplate using epoxy resin glue or screws. The design has avoided spring?loaded optical mounts, ensuring stress and thermal stability and effectively enhancing the stability of the spatial optical path. Furthermore, the precise temperature controls have been implemented for both spatial optical path modules. The reliability of the spatial optical path has been further enhanced. During temperature experiment ranging from 0 °C to 40 °C, the internal temperature fluctuation is less than 0.1 ℃, and the peak?to?peak power fluctuation is less than 8%. The integrated optical system achieves a sensitivity of 323.4 μGal?/Hz@T = 20 ms in dynamic atom interferometer and long?term stability of 10.3 μGal@1 000 s. This design provides an effective solution for the miniaturization and practical application of atomic interferometers.

Abstract:In order to solve the problem of high temperature gas flow field test in the whole process measurement of aero engine, a rotating multi?section and multi?parameter flow field scanning and measurement device was developed. The designed rotary scanning measurement section was used to replace the original hybrid diffuser section of a certain type of aero engine, the circumferential measurement point encryption was realized by controlling the rotation of the measurement section, and the temperature field, pressure field, velocity field, direction field and other parameters were measured at the turbine outlet and afterburner inlet of the aero engine at the same time. The feasibility of the design of the rotary scanning measurement device, the layout design of the temperature / pressure / velocity multi?field synchronous test, the reliability design of the probe, the accurate measurement of the temperature of high?temperature gas with a large declination angle, and the complex three?dimensional flow field measurement scheme with a large declination angle were verified by experiments. Then, tests were conducted under the test conditions of a certain type of aircraft engine to verify the practical application effect of the rotating multi?section and multi?parameter flow field scanning measurement device. This study provides important technical support for the performance evaluation and component matching research of aircraft engines.

Abstract:To meet the on?site in?situ calibration requirements of precision data collectors used in aircraft engine test benches, a comprehensive in?situ calibration system for data collectors has been developed. A low thermoelectric potential scanning switch was designed, and the data collector calibration software was developed for controlling multifunctional calibration sources, low thermoelectric potential scanning switches, and precision data collectors to achieve on?site in?situ calibration. The low thermoelectric potential path switching technology was used to automatically convert and collect multiple signals. Automated and parallelized execution of calibration programs was realized through multi?threaded calibration technology. The application effect of the in?situ comprehensive calibration system for aircraft engine test bench data collectors was verified through experiments. The results showed that the accuracy of the system met the requirements, and the time required to calibrate a single data collector using the system was only 3 hours, which was more than 6 times more efficient than traditional manual calibration methods. This system provides strong support for achieving efficient, convenient, and on?site calibration of multi?channel data collectors, and provides important reference for the research of in?situ automation calibration technology for other measuring equipment.