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The purpose of this paper is to propose a fault diagnosis method for rolling bearings, in which the fault feature extraction is realized in a two-dimensional domain using scale invariant feature transform (SIFT) algorithm. This method is different from those methods extracting fault feature directly from the traditional one-dimensional domain.

The vibration signal of rolling bearings is first transformed into a two-dimensional image. Then, the SIFT algorithm is applied to the image to extract the scale invariant feature vector which is highly distinctive and insensitive to noises and working condition variation. As the extracted feature vector is high-dimensional, kernel principal component analysis (KPCA) algorithm is utilized to reduce the dimension of the feature vector, and singular value decomposition technique is used to extract the singular values of the reduced feature vector. Finally, these singular values are introduced into a support vector machine (SVM) classifier to realize fault classification.

The experiment results show a high fault classification accuracy based on the proposed method.

The proposed approach for rolling bearing fault diagnosis based on SIFT-KPCA and SVM is highly effective in the experiment. The practical value in engineering application of this method can be researched in the future.

This paper aims to present an investigation on flight quality analysis and design of tilt-rotor aircraft combined with corresponding flight quality specifications.

From the perspective of modal characteristics of tilt-rotor aircraft, it focuses on the analysis of the change rules of the longitudinal short-term motion mode, lateral roll convergence mode, spiral mode and Dutch roll mode. Then, the flight quality design research is carried out using the explicit model tracking control method. The quantitative relationship between flight quality requirements and explicit model is established. Accordingly, the closed-loop flight quality of XV-15 tilt-rotor aircraft is evaluated.

The stability of spiral mode is the result of the interaction of various aerodynamic derivatives and spiral instability occurs in helicopter mode. The other motion modes are stable in full flight mode and meet the requirements of level 1 specified in ADS-33E-PRF and MIL-F-8785C flight quality specifications. There is a quantitative relationship between flight quality requirements and explicit model, and the flight quality of tilt-rotor aircraft is improved through the explicit model tracking control method.

The presented analysis results showed the influence of motion modes and flight quality and the effectiveness of explicit model tracking control method in flight quality improvement, which could be considered as new information for further flight quality design of tilt-rotor aircraft.

The originality of the paper lies in the proposed design and analysis method of the flight quality of tilt-rotor aircraft from the direction of the influence of its aerodynamic derivatives and motion modes.

This paper aims to clarify the corrosion inhibition effect of different corrosion inhibitor systems on the corrosion of metal pipe string by potassium persulfate plugging agent, so as to improve the injection capacity of polymer plugging well and reduce the corrosion of steel by oxidant plugging agent.

The effect of different corrosion inhibitors on the corrosion inhibition of N80 carbon steel in 1% potassium persulfate solution was studied by electrochemical experiment and weight loss experiment. The corrosion inhibition mechanism of potassium persulfate inhibitor and the synergistic mechanism among different inhibitors were analyzed.

The results indicated that when the temperature was 50°C, the inhibition effect of 0.2% sodium molybdate with a single inhibitor was the best at pH 8.5, and the inhibition rate was 70.17%. The inhibition efficiency of 0.2% sodium molybdate + 0.3% sodium silicate in the composite inhibition system can reach 94.38%. In the temperature range of 20°C–60°C, with the increase of system temperature, the inhibition effect of corrosion inhibitor will gradually weaken.

The corrosion inhibition system of N80 steel in potassium persulfate oxidant was mainly studied, and it clarified the influence of temperature and pH value on the corrosion inhibition effect, which provided guidance and suggestions for the corrosion inhibition of tubular string in the oilfield.

Based on resource-based theory and intellectual capital theory, this paper aims to investigate the impact of digital investment on enterprise value and the mediating role of intellectual capital. Additionally, it explores the heterogeneous impacts of digital investment on enterprise value and intellectual capital.

The study utilizes a sample of listed companies in Chinese A-shares from 2013 to 2020. The entropy-weighted method is applied to measure digital investment from two dimensions: scale and increment. Finally, the research hypotheses are tested through multiple regression analysis.

The empirical results demonstrate that digital investment significantly and positively impacts enterprise value. From the channel mechanism test, digital investment can enhance enterprise value by influencing intellectual capital through human, structural and relational capital. Of these, the mediating effect of human capital is the most significant. Moreover, the impacts of digital investment on enterprise value and intellectual capital are related to the industry sectors. In the agricultural sector, digital investment has adverse effects. In the industrial and service sectors, digital investment promotes intellectual capital and enterprise value. However, in the service sector, the impact on relational capital is not significant, and the mediating effect of relational capital does not hold.

This research has a limited potential for generalization due to the lack of standard measurement models for the exploration of digital investment.

The research findings are valuable for assessing the economic effects of digital investment comprehensively and providing essential information for policy formulation and strategy implementation.

This study represents the first attempt to evaluate the relationship between digital investment and enterprise value using the entropy-weighted method. In addition, this study investigates the mediating role of intellectual capital.

This paper aims to understand the influence of cylinder liner temperature on friction power loss of piston skirts and the synergistic effect of cylinder liner temperature on lubrication and heat transfer between piston skirt and cylinder liner.

A method to calculate the influence of cylinder liner temperature on piston skirt lubrication is proposed. The lubrication is calculated by considering the different temperature distribution of the cylinder liner and corresponding piston temperature calculated by a new multilayer thermal resistance model. This model uses the inner surface temperature of the cylinder liner as the starting point, and the starting temperature corresponding to different positions of the piston is calculated using the time integral average. Besides, the transient heat transfer of mixed lubrication is taken into account. Six temperature distribution schemes of cylinder liner are designed.

Six temperature distributions of cylinder liner are designed, and the maximum friction loss is reduced by 34.4% compared with the original engine. The increase in temperature in the second part of the cylinder liner will lead to an increase in friction power loss. The increase of temperature in the third part of the cylinder liner will lead to a decrease in friction power loss. The influence of temperature change in the third part of the cylinder liner on friction power loss is greater than that in the second part.

The influence of different temperature distribution of cylinder liner on the lubrication and friction of piston skirt cylinder liner connection was simulated.

The brake controller is a key component of the locomotive brake system. It is essential to study its safety.

This paper summarizes and analyzes typical faults of the brake controller, and proposes four categories of faults: position sensor faults, microswitch faults, mechanical faults and communication faults. Suggestions and methods for improving the safety of the brake controller are also presented.

In this paper, a self-judgment and self-learning dynamic calibration method is proposed, which integrates the linear error of the sensor and the manufacturing and assembly errors of the brake controller to solve the output drift. This paper also proposes a logic for diagnosing and handling microswitch faults. Suggestions are proposed for other faults of brake controller.

The methods proposed in this paper can greatly improve the usability of the brake controller and reduce the failure rate.

This study aims to focus on the clothing recycling supply chain and aims to provide optimal decisions and managerial insights into supply chain strategies, thereby facilitating the sustainable development of the clothing industry.

Based on previous single- and dual-channel studies, game theory was employed to analyze multiple recycling channels. Concurrently, clothing consumer types were integrated into the analytical models to observe their impact on supply chain strategies. Three market scenarios were modeled for comparative analysis, and numerical experiments were conducted.

The intervention of fashion retailers in the clothing recycling market has intensified competition across the entire market. The proportions of various consumer types, their preferences for online platforms and their preference for the retailer’s channel influence the optimal decisions and profits of supply chain members. The diversity of recycling channels may enhance the recycling volume of clothes; however, it should meet certain conditions.

This study extends the existing theory from a channel dimension by exploring multiple channels. Furthermore, by investigating the classifications of clothing consumers and their influence on supply chain strategies, the theory is enhanced from the consumer perspective.

The purpose of this paper is to examine the construction of national heritage through the interpretation of sites and events, with a particular focus on hot interpretation at difficult heritage sites. 

This paper examines the processes of difficult heritage interpretation at the Memorial Hall of the Nanjing Massacre over the past 30 years, and examines the resulting political implications.

Aligning with contemporary national social and political agendas, heritage interpretation at the Memorial Hall actively serves as an authorised educational tool. Despite the hot interpretation techniques used to stimulate the emotional impact of visitor experiences, this particular traumatic past has been utilised in nation building practices that legitimise specific histories and form a national image on an international stage.

Heritage interpretation of difficult history will benefit from open dialogue and assessment of the past from multiple perspectives. This requires all stakeholders to work together to develop interpretation strategies that acknowledge and prioritise the needs of post-conflict societies. Without this form of open dialogue and reflection, the official claims of heritage interpretation achieving reconciliation between conflicted peoples remain superficial. 

This study offers a novel contribution to the discussion of heritage interpretation. The results shed light on the cultural processes surrounding state interpretation of traumatic pasts for specific political uses. The study suggests ways in which heritage sectors and authorities can achieve social goals, such as public education, reconciliation and peacebuilding, through such processes of heritage interpretation.