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This paper aims to enhance lubrication performance of the pitcher plant–like textured surface with various parameters.

A pitcher plant–like structure surface is fabricated on the copper alloy, and the lubrication performance of the pitcher plant–like structure with various parameters is evaluated. In addition, the pressure distribution and oil film load capacity of the pitcher plant–like surface are simulated based on Navier–Stokes equations.

When the direction of motion aligns with the pitcher plant–like structure, the friction coefficient remains lower than that of the nontextured surface, and it exhibits a decreasing trend with the increasing of the texture width and spacing distance; the lowest friction coefficient (0.04) is achieved with B = 0.3 mm, L = 1.0 mm and θ = 45°, marking a 75% reduction compared to the nontextured surface. Simulation results demonstrate that with the increase in texture width and spacing distance, the oil film load-bearing capacity demonstrates an increasing trend.

Bionic pitcher plants are prepared on the copper alloy to improve the lubrication performance and wear resistance.

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-04-2024-0119/

Under fix-position preload, the high rotation speed of the angular contact ball bearing exacerbates the frictional heat generation, which causes the increase of the bearing temperature and the thermal expansion. The high rotation speed also leads to the centrifugal expansion of the bearing. Under the thermal and centrifugal effect, the structural parameters of the bearing change, affecting the mechanical properties of the bearing. The mechanical properties of the bearing determine its heat generation mechanism and thermal boundary conditions. The purpose of this paper is to study the effect of centrifugal and thermal effects on the thermo-mechanical characteristics of an angular contact ball bearing with fix-position preload.

Because of operating conditions, elastic deformation occurs between the ball and the raceway. Assuming that the surfaces of the ball and channel are absolutely smooth and the material is isotropic, quasi-static theory and thermal network method are used to establish the thermo-mechanical coupling model of the bearing, which is solved by Newton–Raphson iterative method.

The higher the rotation speed, the greater the influence of centrifugal and thermal effects on the bearing dynamic parameters, temperature rise and actual axial force. The calculation results show that the effects of thermal field on bearing dynamic parameters are more significant than the centrifugal effect. The temperature rise and actual axial force of the bearing are measured. Comparing the calculation and the experimental results, it is found that the temperature rise and the actual axial force of the bearing are closer to reality considering thermal and centrifugal effects.

In the past studies, the thermo-mechanical coupling characteristics research and experimental verification of angular contact ball bearing with fix-position preload are not concerned. Research findings of this paper provide theoretical guidance for spindle design.

This paper aims to improve the wear resistance of titanium alloy using a high-hardness boride layer, which was fabricated on Ti6Al4V by a high-temperature boronizing process.

The boride layers on Ti6Al4V were obtained at 1000°C for 5–15 h. Scanning electron microscopy, energy dispersive analysis and X-ray diffractometer were used to characterize the properties of the boride layer. The tribological performance of the boride layer at room and elevated temperatures was investigated.

The X-ray diffraction analysis showed that the boride layers were a dual-phase structure of TiB and TiB₂. When the boronizing time increased from 5 h to 15 h, the microhardness increased from 1192 HV_0.5 to 1619.8 HV_0.5. At 25°C and elevated temperatures, the friction coefficients of the boride layers were higher than that of Ti6Al4V. The wear track areas of T-5 at 200°C and 400°C were 2.5 × 10^–3 and 1.1 × 10^–3 mm², respectively, which were 6.1% and 2.6% of that of Ti6Al4V, indicating boride layer exhibited a significant wear resistance. The wear mechanisms of the boride layer transformed from slight peeling to oxidative wear and abrasive wear as the temperature was raised.

The findings provide an effective strategy for improving the wear resistance of Ti6Al4V and have important implications for the application of titanium alloy in a high-temperature field.

The purpose of this paper is to research on optimization of spindle bearing preload based on efficiency coefficient method and provide theoretical guidance for variable preload of intelligent spindle.

Based on an established thermo-mechanical coupling model of angular contact ball bearing with fix-position preload, temperature rise and axial stiffness of the bearing at different speeds and preload are analyzed, and life of the bearing is estimated by the improved L-P theory. The bearing temperature rise, axial stiffness and life data are standardized, and the preload is optimized by the efficiency coefficient method according to the requirements of operating conditions.

The optimized preload meets comprehensive requirements of the bearing temperature rise, axial stiffness and life under different operating conditions.

In the past studies, it is rarely reported that temperature rise, stiffness and life of the bearing under thermo-mechanical coupling effect are used as objective functions to optimize preload at different speeds.

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-06-2020-0205/

This paper aims to synthesize a novel alkanolamine borate and explore the performance of as a copper wire drawing oil.

In this paper, a copper wire drawing oil (CU-KL) was formulated by using a novel alkanolamine borate, naphthenic base oil, fatty alcohol polyoxyethylene ether and palm oil. The tribological performance of CU-KL and commercial copper wire drawing oils (CU-DRB and CU-8010) was investigated

Under applied loads of 5 N-15 N, the average friction coefficient of CU-KL was 29.4%, 5.4% and 25.3% lower than that of CU-DRB, respectively. At sliding speed of 1000–5000 rpm, the average friction coefficient of CU-KL was reduced by 14.3%, 6% and 10.3% compared with CU-DRB, respectively. Through scanning electron microscope and energy dispersive spectrometry, CU-KL can form B-containing compound at the contact interface, which could synergistically enhance the lubrication effect and improve the wear resistance.

The properties of CU-KL under different test condition were studied, and the findings are of great significance for the application of alkanolamine borate in copper wire drawing oil.

This study aims to solve the premature failure of the rubber stator due to wear, reduce the frictional resistance moment of the screw pump to solve the problem of a model of Daqing oilfield screw pump oil recovery system shutdown after the difficult start.

For the first time, the rotor surface of a screw pump was treated with dot-matrix texture to study the effect of dot matrix texture on the tribological performance of the stator-rotor friction subsets of screw pump. Reciprocating friction tests with different texture morphologies (S-shape, double tongue) and angular parameters (0°, 45° and 90°) were conducted at 10% of the texture area and pump silicone grease.

When point texture was added to the surface of the rotor sample, the friction coefficient and wear quantity of the sample were lower than those of the surface without texture treatment, and the double tongue 0° combination showed the best tribological properties. At this time, the average coefficient of friction and wear is reduced by 22.8% and 62%, 28.6% and 64.8%.

The introduction of texture can effectively improve the tribological performance of progressive screw pumps, and this paper provides important theoretical and experimental support for the design of progressive screw pumps in practical applications.

This paper aims to realize an in-situ quality inspection system rapidly for new injection molding (IM) tasks via transfer learning (TL) approach and automation technology.

The proposed in-situ quality inspection system consists of an injection machine, USB camera, programmable logic controller and personal computer, interconnected via OPC or USB communication interfaces. This configuration enables seamless automation of the IM process, real-time quality inspection and automated decision-making. In addition, a MobileNet-based deep learning (DL) model is proposed for quality inspection of injection parts, fine-tuned using the TL approach.

Using the TL approach, the MobileNet-based DL model demonstrates exceptional performance, achieving validation accuracy of 99.1% with the utilization of merely 50 images per category. Its detection speed and accuracy surpass those of DenseNet121-based, VGG16-based, ResNet50-based and Xception-based convolutional neural networks. Further evaluation using a random data set of 120 images, as assessed through the confusion matrix, attests to an accuracy rate of 96.67%.

The proposed MobileNet-based DL model achieves higher accuracy with less resource consumption using the TL approach. It is integrated with automation technologies to build the in-situ quality inspection system of injection parts, which improves the cost-efficiency by facilitating the acquisition and labeling of task-specific images, enabling automatic defect detection and decision-making online, thus holding profound significance for the IM industry and its pursuit of enhanced quality inspection measures.

In the current literature, there is little systematic research on the relationship among adjustment of the income distribution, change in economic structure and improvement of macroeconomic efficiency.

This paper expands Marx's reproduction schema into the “Marx–Sraffa” three-department structure table comprising fixed capital, general means of production and means of consumption and employs China's input–output table from 1987 to 2015 to portray the relationship between income distribution and macroeconomic efficiency under investment-driven growth.

This paper calculates the wage–profit curve of China's economy and evaluates the space of macroeconomic efficiency improvement in China based on the deviation between actual and potential income distribution structure.

The results show that there is a downward trend of the profit rate, which meets Marx's theoretical prediction, and the decline in the profit rate is mainly attributed to an increase in the organic composition of capital arising from the rapid growth of fixed capital investment under extended growth. The analysis of macroeconomic efficiency shows that the space for improving macroeconomic efficiency is extremely limited under traditional growth pattern and that China must transform its economic development pattern and foster new economic growth drivers.

Economic statecraft is a critical aspect of China’s foreign policy and has played a vital role in China’s relations with its Asian neighbors. The Chinese economic ties with Asia are significant not only because China is the second largest economy in today’s world but also because it has an important impact on regional economic co‐operation and international supply chains. Relentless growth in military buildup and more assertive foreign policy led many pundits to focus almost exclusively on political and military aspects of the Chinese grand strategy in Asia. The purpose of this study is to re‐examine this picture by studying China’s economic statecraft in the region.

This paper will address following research questions: How does the Chinese foreign economic policy serve its political aspirations in East Asia? Why has China increasingly relied on a combination of economic pressures and incentives to achieve its foreign policy objectives? How effective is China’s economic diplomacy as a strategic weapon? What are the limitations of such policy? What challenges does Beijing face in exercising its economic power in East Asia?

Beijing has a comprehensive, long-term grand strategy in Asia, and economic statecraft is a major component of it. Economic statecraft is a double-edged sword. It has given the People’s Republic of China more political influence but frictions and disputes between China and its trading partners are growing as well. Even with the slower growth of the Chinese economy, China will continue to be a game changer for the region. The economic diplomacy has long been part of the foreign policy toolkit used by the People’s Republic of China and will play more important role in the years to come.

Thus far, China’s expanding economic ties with many countries in the world have not generated significant spillover effects. Although China is the dominant economic partner for every country in East Asia, its “soft power” remains to be weak. With the slower growth of the Chinese economy, another looming issue is whether China is going to be able to make a shift away from a trade- and export-led growth model that brought its dramatic economic success. All these could lead China’s economic statecraft less potent. Meanwhile, it should be noted that Asian economies that once relied on the USA are reaching a turning point as China comes to the fore, a trend that may challenge the existing international order. Should this momentum continue, it could alter the balance of power between Washington and Beijing in the region.

For Beijing, economic statecraft concerns both the economic dimension of foreign policy and the strategic dimension of economic policy. Although there is a growing literature on China’s soft power and military capabilities, the study of the economic dimensions of China’s foreign policy remains underdeveloped. With rising confidence and sophistication, Beijing has deployed economic resources to achieve geopolitical aims.

Needless to say, China’s economic statecraft has already triggered heated debate in the United States, Asia and elsewhere in the international community. However, the study of the Chinese economic diplomacy has received relatively little scholarly attention in the English-speaking world. This paper will fill a gap in the analysis and literature.