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This study aims to investigate the surface modification on 20CrMnTi gear steel individually treated by diamond-like carbon films and nitride coatings.

For this purpose, the mechanical properties of a-C:H, ta-C and AlCrSiN coatings are characterized by nano-indentation and scratch tests. The friction and wear behaviors of these three coatings are evaluated by ball-on-disc tribological experiments under dry contact conditions.

The results show that the a-C:H coating has the highest coating-substrate adhesion strength (495 mN) and the smoothest surface (Ra is about 0.045 µm) compared with the other two coatings. The AlCrSiN coating shows the highest mean coefficient of friction (COF), whereas the ta-C coating exhibits the lowest one (steady at about 0.16). The carbon-based coatings possess excellent self-lubricating properties compared with nitride ceramic ones, which effectively reduce the COF by about 64%. The major failure mode of carbon-based coatings in dry contact is slight abrasive wear. The damage of AlCrSiN coating is mainly adhesive wear and abrasive wear.

It is suggested that the carbon-based film can effectively improve the friction-reducing and wear resistance performance of the gear steel surface, which has a promising application prospect in the mechanical transmission field.

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-05-2023-0129/

The purpose of this paper is to improve the film stiffness of a dry gas seal (DGS) through the proper design of 3D macroscopic surface structures based on numerical study.

A novel generalized three-dimensional (3D) geometric model is proposed to characterize macroscopic surface structures of a DGS, including grooves, waviness, radial taper and step. The mathematical model is established to simulate film pressure distribution. The effect of the surface profile and groove bottom profile on the steady-state performance of DGSs at different working conditions is investigated.

The unidirectional groove surface has the largest film stiffness at different speed conditions and the largest opening force at medium and high speed, whereas the annular groove has the largest opening force at static pressure. For obtaining the maximum film stiffness, unidirectional combined variable depth groove surface when ns = 0.4 and k = 0.5 outperforms the other unidirectional groove surfaces, whereas circumferential waviness when ns = 1 and k = 1 is the best choice among annular groove surfaces.

This study proposes a novel generalized 3D geometric model to characterize macroscopic surface structures of a DGS. The optimal groove bottom profile for different surface profiles of DGS is presented.

This study is dedicated to systematically collating the distribution and utilization circumstances of geothermal resources in China. Moreover, it endeavors to formulate a comprehensive utilization scheme for geothermal resources during the construction and operation phases of the railway, thereby furnishing robust support and valuable reference for the holistic utilization of geothermal resources along the railway corridor.

Through an in-depth analysis of the extant utilization of geothermal resources in China, it is discerned that the current utilization modalities are relatively rudimentary, bereft of rational planning and characterized by a low utilization rate. Concurrently, by integrating the practical requisites of railway construction and operation and conducting theoretical dissections, a comprehensive utilization plan for the construction and operation periods of railway is proffered.

In light of the railway’s construction and operation characteristics, geothermal utilization models are categorized. During construction, comprehensive modalities include tunnel illumination power generation, construction area heating, tunnel antifreeze using shallow geothermal energy, tunnel pavement antifreeze and construction concrete maintenance. During operation, they comprise operation tunnel antifreeze, railway roadbed antifreeze, railway switch snow melting and deicing, geothermal power station establishment and railway hot spring health tourism planning.

According to the characteristics and actual needs of railway construction and operation, it is of great significance to rationally utilize geothermal resources to promote the construction and operation of green railways.

This study aims to evaluate the efficacy of a digital medical library, including department-based electronic journal access, library training course participation and scholarly publications.

The data on full-text electronic journal access, participants of library training courses and scholarly publications were exported from a digital medical library database during 2017–2021. In addition, electronic journal access and library training courses were divided into high-level and low-level groups, while scholarly publications were divided into physician and non-physician groups.

The scholarly publications had a positive correlation to library training courses and electronic journal access. Furthermore, scholarly publications showed a significant difference between the high-level and low-level electronic journal access groups but not between the high-level and low-level library training course groups. Scholarly publications and electronic journal access had positive correlations for both the physician and non-physician groups. Scholarly publications and library training courses, and electronic journal access and library training courses had positive correlations only in the non-physician group.

The importance of electronic journal access for scholarly publications is suggested based on the findings of the present study. The training courses held by the medical library had a positive effect on scholarly publications for the non-physician group.

The current study provides insights relevant to the electronic journal access of library-supported scholarly publications among medical departments. These results can serve as a reference for medical library development planning and decision-making in the future.