Photon diffusion in thermal barrier coatings (TBCs) significantly deteriorates the overall performance of gas turbines operating at high temperatures. This study presents the strategy of high‐temperature photon suppression, based on a ceramic composite consisting of the second component with a smaller refractive index and controlled particle size. Using the Mie theory, it is theoretically demonstrated that controlling the second component particle size closer/equal to the infrared radiation wavelength region (1–5 μm) could reduce photon diffusion. Ceramic composites comprised of 8 wt.% yttria‐stabilized zirconia (8YSZ, matrix) and corundum (second component) with different particle sizes were prepared. The total and the photon thermal conductivity of the 8YSZ/corundum composites are lower than pure 8YSZ by ∼48.9% and ∼96.4% at 1200°C, respectively. With the addition of corundum into 8YSZ, the thermal radiation transport of 8YSZ is significantly suppressed due to the photon scattering produced by the lower refractive index and proper particle size of the corundum. Besides, the fracture toughness and hardness of composites increased by ∼20% and ∼13%, respectively, compared to the 8YSZ. Composite with the corundum particles size of 1 μm displays the lowest values of total and photon thermal conductivity at high temperature.

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Elliptical ultrasonic vibration assisted milling (EUVAM) is widely used as an efficient processing method for hard-to-machining materials such as titanium alloy, superalloy, and hard-brittle materials. To uncover the mechanism of the intermittent cutting characteristics in EUVAM, the tool-workpiece contact rate model is developed by combining with the kinematic relationship between the tool edge and the workpiece in the process. According to the analysis of the contact rate model, the phenomenon that the contact rate increases rapidly with the time-varying tooth position angle in onedimensional ultrasonic vibration assisted milling can be improved in EUVAM. In addition, considering the variation of window function and undeformed cutting thickness, a force model is established. And the experiment of EUVAM is performed to verify the model of ultrasonic milling force, and the influence of process parameters (amplitude, cutting speed, feed rate and cutting depth) on ultrasonic milling force is also analyzed.

The GNSS time transfer technology is the high precision time transfer method based on the navigation satellite system and has been widely applied in time and frequency. Benefiting from the development of GNSS time transfer technology and the expansion of user needs for real-time time service applications, real-time time transfer technology has become an important research direction. GNSS Precise Point Positioning (PPP) is one of the most commonly used methods of GNSS time transfer technology. With the development of the many facilities, the application of the real-time GNSS PPP has become wider and wider. In this paper, we demonstrate and evaluate the performance of the international GNSS service (IGS) products in the near real-time PPP time transfer technology. A set of the PPP solutions were computed from the observed data from the timekeeping laboratories, and three types of products provided by IGS, including Ultra-Rapid (IGU), Rapid (IGR), and Final (IGS final) orbit and clock offset products. IGS final and IGR products have extremely high accuracy and stability and are used as a reference for the time transfer with IGU product. The near real time clock offset and the comparison link performed with the IGU product can provide a time comparison service with an accuracy of 0. 5ns for near real time applications.