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Current numerical research on snow accumulation on bogies often simplifies train models as 1.5 cars or 3 cars, and there is less research on long marshalling trains with real bogies. In this article, based on the Euler–Lagrange method, the airflow structure and snow accumulation characteristics in the bogie area of an 8-car high-speed train (HST) are studied by numerical simulation. The results show that the airflow velocity and snow distribution concentration inside the bogie cabin vary along the flow direction. The downstream bogie cabin has a lower airflow speed, spatial snow particle concentration, and components snow accumulation. Because of the bogie cabin cover structure, the main airflow direction above the first and second bogie cabin is different, resulting in higher snow concentration and range on the windward side of the first bogie. There is a significant difference in snow accumulation characteristics between powered and nonpowered bogies. The powered bogie gearbox is directly affected by the airflow carrying snow particles, leading to severe snow accumulation on the windward side. This study provides a research foundation and engineering guidance for the snow protection strategy of HST bogies and is important for improving the comfort and safety of HSTs on snow-covered rails. [ABSTRACT FROM AUTHOR]

CoCrMo alloys are often used in the manufacture of artificial joints in the medical field, and their special working environment will lead to corrosion and abrasion of the surface materials, thus reducing the service life of the joints. Surface texturing technology can improve the friction performance of joints by reducing the friction area, storing abrasive particles and lubricants, etc. Its application in the field of CoCrMo alloy joint surface strengthening is of great significance. This paper analyses the characteristics of surface fabrication processing technology and the friction reduction mechanism of surface fabrication under fluid lubrication and dry friction conditions, summarizes the influence of various fabrication parameters (fabrication depth, size, density, shape, etc.) on the friction performance of the alloy, introduces other surface technologies of CoCrMo alloy as well as common medical materials, summarizes the existing problems in the research of CoCrMo alloy surface reinforcement technology at this stage and makes a study on the development direction of the surface reinforcement technology of CoCrMo alloy in the field of artificial joints. The development direction of CoCrMo alloy in the field of artificial joints is also prospected. [ABSTRACT FROM AUTHOR]

In the biomedical field, the commonly used metal implant materials are prone to "stress shielding" because of their mechanical properties and elastic modulus are very different from human bone. The mechanical properties of metal materials are often difficult to maintain in corrosive media and release harmful ions. Nor can it reliably establish a sufficient combination with human bones, resulting in a service life that does not reach the desired goal. Researchers in this field propose to combine the superior mechanical properties of metals with bioactive materials, such as bioactive ceramics and the emerging ferrous glass, and achieve this through surface modification techniques. The laser cladding technique is of great interest for its low dilution rate, high bond strength and fine organisation. This review paper describes the development of common medical metal materials and the research progress of laser cladding surface modification technology. [ABSTRACT FROM AUTHOR]