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The transpiration has been recognized as one of the most effective thermal protection methods for future hypersonic vehicles. To improve efficiency and safety, it is urgent to optimize the design of the transpiration system for heat and drag reduction. The purpose of this paper is to investigate the effects of transpiration on heat and drag reduction.

A chemical nonequilibrium flow model with the transpiration is established by using Navier–Stokes equations, the shear-stress transport turbulence model, thermodynamic properties and the Gupta chemical kinetics model. The solver programmed for this model is verified by comparing with experimental results in the literature. Effects of air injection on the flow field, the aerodynamic resistance and the surface heat flux are calculated with the hypersonic flow past a blunt body. Furthermore, a modified blocking coefficient formula is proposed.

Numerical results show that the transpiration can reduce the aerodynamic resistance and the surface heat flux observably and increase the shock wave standoff distance slightly. It is also manifested that the modified formula is in better agreement with the wind tunnel test results than the original formula.

The modified formula can expand the application range of the engineering method for the blocking coefficient. This study will be beneficial to carry out the optimal design of the transpiration system.

This paper aims to study the impact of external fairness of executive compensation on M&A premium, and examine the moderate role of institutional investors. The high M&A premium is the main factors that induce the huge impairment of listed companies’ goodwill and the plummeting performance. Executives are the decision-makers of M&As, and their decision-making process is inevitably affected by the psychological factors. In recent years, institutional investors have become an important external force that can affect the governance of listed companies.

The authors use M&A data of listed companies from 2008 to 2018 and use OLS regression to test the relationship between executive compensation fairness and M&A premium.

The results show that the lower the external fairness of executive compensation, the greater the M&A premium. Institutional investors can effectively reduce the impact of external compensation unfairness on M&A premiums. The mechanism tests show that executives' psychological perception of fairness induced by external unfairness reduces their motivation to work and prompts them to use high premium to seek alternative compensation incentives. Further examinations of executive characteristics and corporate characteristics show that the role of external unfairness in executive compensation in driving M&A premiums is more pronounced in companies with longer executive tenure, weaker executive reputation incentives and private property.

This paper enriches the research on the pre-factors of M&A premiums from the perspective of executives’ psychological perception of fairness, provides evidence that institutional investors play a positive governance role and provides decision-making references for companies to take corresponding measures to reduce M&A premium risks.

This paper aims to clarify the relationship between the cone bit seal failure and the down-hole drilling fluid pressure and high temperature that occur during ultra-deep well drilling. It proposes that the contact pressure distribution under low pressure conditions is favourable for lubrication and the seal inner wear is serious under high pressure conditions. Furthermore, the more reliable cone bit seal can be obtained using the back propagation (BP) neural network and genetic algorithm (GA) to reduce the drilling cost.

The wear morphologies of the seal surface were analyzed using Contour GT-K to determine the seal contact pressure distribution. Then, the influences of the drilling fluid pressure and high temperature on the metal seal interface were analyzed using finite element method. The structural parameters of the seal under high pressure were optimized based on the BP neural network and GA.

This paper proposes that the inner seal contact pressure increases rapidly with an increase in the drilling fluid pressure. The design parameters of the seal components should be adjusted reasonably to ensure that the outer contact pressure is greater than the inner contact pressure, which is advantageous for forming a lubricant film on the inner side of the seal. The uneven temperature distribution of the seal surface will further aggravate seal failure.

Study on the bit seal with good property is significant in drilling application, and the optimized seal can prolong the cone bit life.

The purpose of this paper is to answer the following two questions: What are the influences of the top managers’ different leadership styles on organizational innovation? What is the mechanism by which the different leaderships exert different effects on organizational innovation?

To test the hypothesized model, a data set based on 133 MBA part-time students from Tsinghua University and Zhejiang University in China was built, after interviewing several top managers as a pilot study. With the help of SPSS macro, hierarchical regression and bootstrapping analysis, the paper analyzes the effects of two leadership styles on innovation performance, through the mediation mechanism of openness involving open breadth and open depth.

The results indicate that transformational leadership enhances, while transactional leadership reduces, the organizational innovation performance. The openness breadth and openness depth not only mediate the beneficial effect of transformational leadership on innovation, but also mediate the deleterious effect of transactional leadership on innovation.

This study empirically explores the different functions of transformational leadership and transactional leadership for leading organizational innovation performance. Furthermore, a new form of organization is an open design or strategy that allows more external knowledge and resources to be absorbed, which is claimed as a new paradigm for organization innovation. This study integrates the concepts of breadth of openness and depth of openness on the basis of open innovation literature, as an intermediate mechanism to explain the different effects of the two forms of top managers’ leadership.

The recent promotion of prefabricated housing (PH) in China has resulted in a prosperous period for its implementation. However, transaction costs (TCs) cause low economic efficiency to stakeholders and hinder the further promotion of PH. No relevant study has yet been made to investigate the TCs and their causes in the PH field. This paper identifies critical TCs and explores the influencing factors from the developers' perspective.

Semi-structured interviews and a questionnaire survey were used to collect data about TCs and influencing factors. The most influential factors are identified with their impacts on particular TCs, yielded from correlation analysis and logistic regression.

From the developers' perspective in China's PH market, this study identified that the most concerning sources of TCs are: hidden costs arising from disputes, extra workloads from design changes, learning costs, intensive communication and coordination in assembly and unexpected information costs in decision-making. The use of an ordered logistic regression approach indicates that the four most influential factors are: qualification of the general contractor, mandatory local policies, owner type and competitiveness of the developer.

To reduce the TCs, experiencing learning and ensuring the design scheme's complicity are recommended to save information searching and exchanging costs. The implications for the PH developers are for them to: (1) professionalize their own organization and (2) procure high-qualified general contractors. For the policymakers, this means they should improve the clarity of the mandatory local policies for PH step-by-step.

By applying the TCs economic theory, this study explores factors that influence TCs in the PH industry. It sheds light on the influencing mechanism behind the TCs in the context of prefabricated housing.

The purpose of this study is to make a prediction of China's energy consumption structure from the perspective of compositional data and construct a novel grey model for forecasting compositional data.

Due to the existing grey prediction model based on compositional data cannot effectively excavate the evolution law of correlation dimension sequence of compositional data. Thus, the adaptive discrete grey prediction model with innovation term based on compositional data is proposed to forecast the integral structure of China's energy consumption. The prediction results from the new model are then compared with three existing approaches and the comparison results indicate that the proposed model generally outperforms existing methods. A further prediction of China's energy consumption structure is conducted into a future horizon from 2021 to 2035 by using the model.

China's energy structure will change significantly in the medium and long term and China's energy consumption structure can reach the long-term goal. Besides, the proposed model can better mine and predict the development trend of single time series after the transformation of compositional data.

The paper considers the dynamic change of grey action quantity, the characteristics of compositional data and the impact of new information about the system itself on the current system development trend and proposes a novel adaptive discrete grey prediction model with innovation term based on compositional data, which fills the gap in previous studies.

The purpose of this study is to determine the cavitation flow characteristics of the high-pressure differential control valve. The relationship between cavitation, flow coefficient and spool angle is obtained. By analyzing the relationship between different spool angles and energy loss, the energy loss at different spool angles is predicted.

A series of numerical simulations were performed to study the cavitation problem of a high-pressure differential control valve using the RNG k–e turbulence model and the Zwart cavitation model. The flow states and energy distribution at different spool angles were analyzed under specific working conditions.

The cavitation was the weakest when the spool angle was 120° or the outlet pressure was 8 MPa. The pressure and speed fluctuations of the valve in the throttle section were greater than those at other locations. By calculating the entropy production rate, the reason and location of valve energy loss are analyzed. The energy loss near the throttling section accounts for about 92.7% of the total energy loss. According to the calculated energy loss relationship between different regions of the spool angle, the relationship between any spool angle and energy loss in the [80,120] interval is proposed.

This study analyzes the cavitation flow characteristics of the high-pressure differential control valve and provides the law of energy loss in the valve through the analysis method of entropy. The relationship between spool angle and energy loss under cavitation is finally proposed. The research results are expected to provide a theoretical basis for the optimal design of valves.

Yi Jing is one of the most archaic works among the Chinese classics. Various schools of thought developed their philosophies from the philosophical perspectives in this book and its influence is wide ranging and far reaching. This paper attempts to show how leaders can approach the Yi Jing beneficially by identifying the principles, values and virtues in each of the 64 scenarios, deriving insights about change and leadership. It also aims to show how the Yi Jing compares with Western management literature.

This paper provides an analysis of Qian Gua of Yi Jing as an example of how leaders can draw insights from Yi Jing about change and leadership.

Qian Gua, which is the first scenario in the Yi Jing, offers us powerful insights about change and leadership by offering: a framework of understanding change and human enterprises, considering the aspects of beginning, process, benefit and sustainability; a framework to understand the leadership development process; and leadership principles of conscientious self‐cultivation, transformational leadership through virtues and riding the tides of change.

A change and leadership model inspired by the Yi Jing should interest business leaders both in the east and the west, and help Westerners gain success in doing business in China or collaborating with the Chinese on a joint venture.

This is the first paper to draw insights about change and leadership through an analysis of Qian Gua of Yi Jing.