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Because of the various geometric descriptions of different bearing types, performance calculation of journal bearing is complicated, and is difficult in traditional model. This paper aims to simplify the calculation of the journal bearing performance, and to reduce the workload.

On the basis of previous research, a general performance calculation model of journal bearing is proposed in this paper. Eccentricity ratio and attitude angle of axis to each pad are calculated by coordinates of spindle center and each pad center by establishing the unified coordinate system. The surface deformation of journal bearing is taken into consideration, and a correction value is added to the dimensionless oil film thickness.

The performance calculation results of various fix-pad and tilting-pad journal bearings match the results of the existing references very well, revealing the validity of the model. The general model can greatly reduce programming workload, and increase adaptability to different bearings.

Geometric descriptions of both fix-pad and tilting-pad journal bearings are unified in this model, which can be applied to both standard and non-standard journal bearings with different preload ratios. In addition, due to the unification of different bearings types, this model is more conducive to performance comparison among different bearing types, and promotes the development of new structural forms for journal bearings.

The purpose of this paper is to investigate time-optimal control problems for multiple unmanned aerial vehicle (UAV) systems to achieve predefined flying shape.

Two time-optimal protocols are proposed for the situations with or without human control input, respectively. Then, Pontryagin’s minimum principle approach is applied to deal with the time-optimal control problems for UAV systems, where the cost function, the initial and terminal conditions are given in advance. Moreover, necessary conditions are derived to ensure that the given performance index is optimal.

The effectiveness of the obtained time-optimal control protocols is verified by two contrastive numerical simulation examples. Consequently, the proposed protocols can successfully achieve the prescribed flying shape.

This paper proposes a solution to solve the time-optimal control problems for multiple UAV systems to achieve predefined flying shape.

This study aims to investigate how opening high-speed railways affects the cost of debt financing based on China's background.

Using panel data on Chinese listed firms from 2008 to 2017, this study constructs a quasi-natural experiment and adopts a difference-in-difference model with multiple time periods to empirically examine the relation between the high-speed railway openings and debt financing cost.

Our results show that opening high-speed railways reduces the cost of debt financing, and this negative correlation is more significant in non-state firms, firms with weaker internal control, and firms that hire non-Big Four auditors. Besides, we explore the impact mechanisms and find that opening high-speed railways improves analyst attention, institutional investor participation, and information disclosure quality, which in turn lowers the cost of debt financing.

The results imply that the opening of high-speed railways helps to alleviate the information asymmetry and adverse selection between firms and creditors and ultimately reduces the cost of corporate debt financing.

This paper can inform firms and stakeholders about the impact of opening high-speed railways on debt financing cost: it improves the information environment, reduces the geographical location restrictions of debt financing, ensures the reasonable pricing of corporate debt, and thus promotes the healthy and sound development of the debt market.

This paper provides theoretical support and empirical evidence for the impact of infrastructure construction on the information environment of the debt market in China, which enriches the research on the “high-speed railway economy.” In addition, as an exogenous event, the opening of high-speed railways instantly shortens the time distance between firms and external stakeholders, which gives us a natural environment to conduct empirical research, thus providing a new perspective for financial research on firms' geographical location.

This study aims to explore whether and how workplace loneliness leads to cyberloafing and the role of leader problem-focused interpersonal emotion management in buffering this relationship.

Drawing on ego depletion theory, the authors propose that employees' workplace loneliness leads to cyberloafing via ego depletion, while leader interpersonal emotion management (i.e. leadership behavior targeted at managing employees' negative emotions) can help to alleviate the situation. To test this study’s predictions, the authors collected multisource data at three time points from a sample of 219 employee–colleague dyads.

The results show that workplace loneliness is positively related to cyberloafing and that ego depletion mediates this relationship. Leader problem-focused interpersonal emotion management weakens the relationship between workplace loneliness and ego depletion and the indirect relationship between workplace loneliness and cyberloafing via ego depletion such that the above relationships are weak (versus strong) when leader problem-focused interpersonal emotion management is high (versus low).

The study results suggest that workplace loneliness is an important hidden danger that leads to cyberloafing because lonely employees suffer more from ego depletion. Leaders' interpersonal emotion management strategy serves as a potential buffer for such a negative effect.

The purpose of this paper is to propose a wheel/rail mixed lubrication model to study the water lubrication behavior of wheel/rail contact interface.

The numerical simulation method is applied in this paper. A deterministic mixed lubrication model considering surface roughness and transient state is established. The quasi-system numerical and finite difference method are used for numerical solution. The model is verified by comparing with the experimental data in the literature under the same conditions.

Under wet conditions, the change of train speed will change the lubrication state of the wheel/rail contact interface. With an increasing speed, the average film thickness and the film thickness ratio increase, while the adhesion coefficient, the contact load ratio and the contact area ratio decrease. When the creep ratio increases from 0% to 0.5%, the wheel/rail adhesion coefficient and subsurface stress increase sharply. With the increase of axle load, the average film thickness decreases and the adhesion coefficient increases.

This paper aims to improve the mixed lubrication theory by analyzing the characteristics of wheel/rail friction and lubrication, so as to provide some guidance and theory for train driving behavior.

Using the deterministic model, the lubrication state of the wheel/rail contact interface affected by various external factors and the adhesion behavior of wheel/rail progressive process from boundary lubrication to mixed lubrication are studied.

This study aims to investigate how high-speed railway (HSR) development affects urban construction investment (UCI) bond yield spreads based on China’s background.

This study constructs a quasi-natural experiment and adopts regression analyses to empirically examine the relation between HSR development and UCI bond yield spreads. The empirical analysis is based on a Chinese sample of 15,109 bond offering observations from 2008 to 2019.

The results show that HSR development reduces UCI bond yield spreads. Mechanistic analysis shows that HSR development increases land prices and the level of urbanization, which in turn lowers the UCI bond yield spreads. In addition, the impact of HSR development on UCI bond yield spreads is more significant at higher marketization levels and lower degrees of dependence on land finance cities where UCI corporations are located.

The results imply that transportation infrastructure improvement, such as HSR development, helps to enhance the credit of local governments and the solvency of UCI corporations and ultimately reduces the financing cost of UCI bonds.

This paper provides theoretical support and empirical evidence for the impact of transportation infrastructure construction on the implicit debt risks of local governments in China, which enriches the research on the “HSR economy” from a micro perspective and expands the research on the influencing factors of local governments’ debt risk.

This paper seeks to study the tribological properties, corrosion inhibition properties and action mechanism of two triazine‐containing disulfides, TOSS and TOMA, as additives in combustion engine base oil (5CST); those properties of an alkyl disulfide dodecyl disulfide and zinc dialkyldithiophosphate (ZDDP) were also evaluated for comparison to discover whether these additives could be used as potential substitute candidates for ZDDP.

Their tribological performances were evaluated using a four‐ball machine. The worn surfaces were investigated by scanning electron microscopy and X‐ray photoelectron spectroscopy (XPS)

The three additives have good load‐carrying capacity and corrosion inhibition properties comparable with those of ZDDP. The anti‐wear properties of the triazine‐containing disulfides TOSS and TOMA are good but a little inferior to those of ZDDP. The friction‐reducing performances of the additives are better than those of ZDDP. The XPS results show that absorption and tribochemical reactions occur to generate a complex boundary lubrication films comprising inorganic sulfate, sulfide, iron oxide and organic nitrogen, and sulfur‐containing compounds.

The anti‐oxidation properties are still to be estimated, and the synergistic effectiveness with other additives could be demonstrated.

These additives are good extreme pressure and anti‐wear additives in combustion engine base oil and, through further modification of molecular structure or combination with other additives, they may be a potential replacement for ZDDP.

To reduce the cost, the products synthesized were not finely separated. Their tribological properties as additives in the widely used combustion engine base oil were first investigated and results indicate that they show excellent performances.

With the development of social economy, the urbanization of the world has presented a new development trend. The green, ecological, and economic city has gradually attracted people's attention. How to plan new cities and towns to coordinate economic development with nature has been the focus of domestic and foreign scholars. Based on this premise, this article elaborates the domestic and foreign research status of ecological city and puts forward a new type of green ecological civilization from the perspective of evolution of civilization. From the perspective of green ecological economy, the evolution of China's urban planning is studied in terms of the urban and rural areas, nature, pollution, industry, culture, and other aspects. To accumulate experience, green ecological planning in New York is also analyzed at multiple levels, such as urban expansion, energy, and urban water use. According to the development of our country in the past 30 years, the development strategy of urbanization suitable to China's national conditions is introduced on the basis of ecological economy. From the perspective of green ecological planning and economy, practice has proved that new urban planning is able to promote the establishment of a resource-saving society, to enhance the coordinated development of the population, resources, environment, and economy, and to comprehensively improve people's quality of life.

Energy commodities are characterised by rigid demand and high price volatility, linked to many variables such as climate factors, exchange rates, availability of resources. At the same time, the authorities often set prices, so wholesale energy companies need to create margins carefully by managing the procurement process and selecting appropriate tools to manage the risks associated with the volatility of energy prices. The purpose of this paper is to analyse and evaluate price and volume risks in the energy procurement process considering a “non-speculative” point of view, which is understudied in the literature review.

The paper adopts a quantitative approach to risk evaluation, based on accounting indicators, and applies it to a large Italian energy wholesale company.

A set of key risk indicators to measure price and volume risks is presented in the results, split into synthesis risk, unbalanced risks, modulation risks and risks derived from bilateral contracts. These indicators are applied to the case study, and each risk is prioritised and discussed.

This contribution is one of the first attempts to analyse energy procurement risks in a non-speculative approach. The proposed method allows: first, to evaluate and prioritise the three major types in the energy procurement process, second, to observe the trend of risk exposure, third, the performance measurement of the procurement process, and fourth, benchmarking activities if widely implemented in the energy sector.

This paper aims to examine whether rewards incentives of non-state-owned enterprises can settle the matters of motivation lack, strained labor relations and frequent labor-capital conflicts and realize co-win cooperation of workers, enterprises and the society.

Based on the data of 1,617 questionnaires in 257 enterprises, this research reveals the total rewards factors that affect the labor motivation of non-stated-owned enterprises in China and improve labor productivity by adopting the hierarchical linear regression analysis and multi-group path analysis, and establishes a new model of win-win cooperation between labor and capital and the society through the incentive function of these elements by stimulating the enthusiasm of workers, improving labor productivity, increasing profits, expanding capital accumulation and absorbing labor force.

The authors have discovered that in general the main incentives that stimulate the enthusiasm of employees are the factors of performance and recognition and development and career opportunity in total rewards. The factor of benefits also has a significant incentive effect on employees in the western area of China, migrant workers with lower education and male employees, but negative effect on the post-1990s employees in non-state-owned enterprises. However, the compensation factor should be used with caution when encouraging employees in eastern region and the post-1980s. The total rewards factors of development and career opportunities and the performance and the recognition and benefits should be used to motivate workers to improve labor productivity, increase corporate profits and absorb more labor force, which is a long-term solution to win-win cooperation between labor and capital and social sustainable development. It is an important way to increase profits and absorb more labor force by increasing employee’s human capital investment and improving labor proficiency of employees under age 45. The conclusions provide new effective management methods for non-state-owned enterprises in China.

As a consequence, it will encourage employees to improve labor productivity and increase profits and thus absorb more labor force, if we use these factors of performance and recognition, development and career opportunity and benefits integratedly, we will find a permanent solution that the two sides of the labor and management and the society enjoy a win-win cooperation.

The research will provide theoretical basis for non-state-owned enterprises to apply a new and effective management style so that we can establish a win-win cooperation between the labor and management. What’s more, the research will develop the Dual Economy Theory of Lewis and the employment theory of Keynes and will also provide a theoretical basis for the realization of Taylor’s harmonious industrial relations.