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The purpose of this paper is to study the tribological effect of zinc borate ultrafine powder (ZBUP) oil additive on the running-in quality.

The running-in quality was assessed by friction coefficient and surface topography. Fractal parameters including fractal dimension, the width of multifractal, the multifractal difference, multifractal parameters, phase trajectory and correlation dimension were used to extract the nonlinear characteristics of surface topography and friction coefficient.

When the ZBUP additive was added, the convergence degree of the phase trajectory and the stability of the running in were higher than that of base oil. It indicates that the ZBUP additive can improve the running-in quality of sliding bearing. Besides, the ZBUP additive can shorten the running-in time. A boundary protective film, which has good friction-reducing and anti-wear effects, was generated on the surface when the ZBUP additive was added.

The results have a great significance to improve the running-in quality and prolong the service life of the sliding bearing.

Running-in is a transient process prior to steady state and of great importance for mechanical performance. To reveal the fractal behavior in the running-in process, the steel-on-steel friction and wear tests were performed.

The friction coefficient, friction temperature, friction noise and vibration were recorded, and the surface profile of lower sample was measured on line. The signals and profiles were characterized by correlation dimension and box-counting dimension, respectively.

The signals have the consistent fractal evolvement law, that is, the correlation dimension increases and tends to a stable value. The box-counting dimension of one surface becomes close to that of the other surface. The running-in process can be interpreted as a process in which the fractal dimension of friction signals increases, and the counter surfaces spontaneously adapt to and modify each other to form a spatial ordered structure.

The results reveal the running-in behavior from a new perspective.

As a key basic component used in machining, high-speed steel (HSS) tools often prone to wear and failure during machining. Therefore, the purpose of this study is to adopt a suitable approach to improve the stability of the cutting force, the service life and the wear resistance.

Laser shock processing (LSP) was used to process the tool rake face and the tribological test was performed with ball-on-disk wear tester.

Experimental results show that cutting force of the LSP-treated tool is lower than untreated tool under the same cutting conditions. Wear rate of the tool nose treated by LSP decreases obviously and the tool life increases by 40 per cent.

HSS is often used in the manufacture of complex cutting tools. The main value of this article is to improve the tool surface wear resistance, thereby extending the service life of cutter. This paper is valuable not only in theory but also with reference value in engineering practice.

The purpose of this paper is to study the dynamic features of friction coefficient during running-in state based on recurrence analysis, so as to recognize the running-in state of crankshaft journal bearings.

The friction coefficient was measured in the friction experiments and the dynamic features are analyzed by recurrence plots (RPs), unthreshold recurrence plots (URPs) and recurrence quantification analysis.

During the running-in process, RPs have gone through disrupted patterns, drift patterns and homogeneous patterns successively. URP shows that the phase trajectory spirals in the disrupted pattern gradually converge in the drift pattern and remain stable in the homogeneous pattern. Three independent measures, recurrence rate, entropy and laminarity, are chosen to characterize friction coefficient from the perspective of point, diagonal line and vertical line structures of the RPs.

The results provide a feasible way to monitor the running-in process and recognize the running-in state.

The purpose of this paper is to reveal the dynamic contact characteristics of the slip ring. Dynamic contact resistance models considering wear and self-excited were established based on fractal theory.

The effects of tangential velocity, stiffness and damping coefficient on dynamic contact resistance are studied. The relationships between fractal parameters, wear time and contact parameters are revealed.

The results show that the total contact area decreases with the friction coefficient and fractal roughness under the same load. Self-excited vibration occurs at a low speed (less than 0.6 m/s). It transforms from stick-slip motion at 0.4 m/s to pure sliding at 0.5 m/s. A high stiffness makes contact resistance fluctuate violently, while increasing the damping coefficient can suppress the self-excited vibration and reduce the dynamic contact resistance. The fractal contact resistance model considering wear is established based on the fractal parameters models. The validity of the model is verified by the wear tests.

The results have a great significance to study the electrical contact behavior of conductive slip ring.

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-09-2023-0300/

This paper seeks to propose that practical wisdom originating within the Chinese classical traditions has been instrumental in China's ascendance to the world stage. Its purpose is to analyze biographical data across 200 Chinese business leaders in order to gauge the relative influence of two competing ideologies – Maoism and Confucianism.

This paper is based on a two‐step design process. First, modern day leadership archetypes characterizing Maoist and Confucian ideology were developed from the literature. Second, these archetypes were applied in the content analysis of biographical data on Chinese business leaders.

There was evidence of both Maoism and Confucianism in the practices of Chinese business leaders. An unintended, third cohort of leaders emerged, representative of the younger end of the biographical distribution, who appear to embrace paradox in their ideological orientation.

There were three practical implications for management and leadership development: the importance of integrating the concept of paradox into management and leadership development curricula; the provision of illustrative alternatives to western world leadership exemplars; and increased emphasis on global leadership as an emergent phenomenon with particular attention to the burgeoning internationalization of Chinese enterprise and its associated ideologies.

The current leadership literature is dominated by western world exemplars. This paper offers an alternative view; one rich with the wisdom and classical traditions of the Chinese culture.