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With the development of the modern technology and aerospace industry, the noise pollution is remarkably affecting people’s daily life and has been become a serious issue. Therefore, it is the most important task to develop efficient sound attenuation barriers, especially for the low-frequency audible range. However, low-frequency sound attenuation is usually difficult to achieve for the constraints of the conventional mass-density law of sound transmission. The traditional acoustic materials are reasonably effective at high frequency range. This paper aims to discuss this issue.

Membrane-type local resonant acoustic metamaterial is an ideal low-frequency sound insulation material for its structure is simple and lightweight. In this paper, the finite element method is used to study the low-frequency sound insulation performances of the coupled-membrane type acoustic metamaterial (CMAM). It consists of two identical tensioned circular membranes with fixed boundary. The upper membrane is decorated by a rigid platelet attached to the center. The sublayer membrane is attached with two weights, a central rigid platelet and a concentric ring with inner radius e. The influences of the distribution and number of the attached mass, also asymmetric structure on the acoustic attenuation characteristics of the CMAM, are discussed.

In this paper, the acoustic performance of asymmetric coupled-membrane metamaterial structure is discussed. The influences of mass number, the symmetric and asymmetry structure on the sound insulation performance are analyzed. It is shown that increasing the number of mass attached on membrane, structure exhibits low-frequency and multi-frequency acoustic insulation phenomenon. Compared with the symmetrical structure, asymmetric structure shows the characteristics of lightweight and multi-frequency sound insulation, and the sound insulation performance can be tuned by adjusting the distribution mode and location of mass blocks.

Membrane-type local resonant acoustic metamaterial is an ideal low-frequency sound insulation material for its structure is simple and lightweight. How to effectively broaden the acoustic attenuation band at low frequency is still a problem. But most of researchers focus on symmetric structures. In this study, the asymmetric coupled-membrane acoustic metamaterial structure is examined. It is demonstrated that the asymmetric structure has better sound insulation performances than symmetric structure.

Membrane-type acoustic metamaterials (MAMs) recently have been emerged to display useful sound attenuation properties in a low-frequency regime. The purpose of this paper is to present an analytical approach to investigate the transmission loss (TL) of a square membrane-ring structure of MAM. The geometrical effects of ring mass on the TL peak and dip frequencies of the MAM are obtained and discussed.

In this paper, based on the wave propagation and vibration theory, considering the effects of ring mass and acoustic pressure on the membrane, an analytical model is presented to analyze acoustic response of MAM.

Multiple peak frequencies and wide bandwidth appear in the membrane-ring structure, and they can be tuned by changing the location or numbers of the ring mass on the membrane. It is a useful method for designing such type of metamaterial.

In this paper, an analytical method is presented to evaluate the effects of ring geometric on the TL performance of square membrane-type locally resonant metamaterial. It is proved that achieving broadband and multi-peak TL profile in a single cell can indeed happen by increasing additional ring mass. The TL and frequency bandwidth can be tuned by changing the location, adding numbers and varying mass distribution of the ring masses on the membrane.

As a good absorbing material candidate, a functionally graded wave absorber can be tailored to satisfy the impedance match principle by gradually changing material property. The paper aims to discuss these issues.

The electromagnetic wave absorption properties are discussed. An analysis model is proposed to provide an insight into its mechanical characteristics during wave absorption. Considering the energy-converting and thermal deformation properties, the thermoelastic behaviors of an absorber are analyzed by numerical method. The effects of material and geometrical properties are discussed in detail.

The results demonstrate that absorbing effect of graded composite is enhanced. Good performance of low reflectance and high absorption with gentle thermal stress distribution can be obtained by proper designing of the gradient absorber.

Functionally graded materials exhibit a progressive compositional gradient change along certain dimension of structures, which can be used as absorbing materials for the gradual change of material property tailored to satisfy the principle of impedance match. The design of functionally graded absorbing materials usually should consider not only the electromagnetic performance, but also the mechanical properties simultaneously. Therefore, few investigations have addressed the mechanical characteristics of absorbers. This paper presents some studies on the electromagnetic, especially mechanical behaviors during electromagnetic wave absorption. It is helpful to provide mechanical reference for designing an absorber.

As a kind of NP-hard combinatorial optimization problem, pipe routing design (PRD) is applied widely in modern industries. In the offshore oil and gas industry, a semi-submersible production platform is an important equipment for oil exploitation and production. PRD is one of the most key parts of the design of semi-submersible platform. This study aims to present an improved ant colony algorithm (IACO) to address PRD for the oil and gas treatment system when designing a semi-submersible production platform.

First, to simplify PRD problem, a novel mathematical model is built according to real constraints and rules. Then, IACO, which combines modified heuristic function, mutation mechanism and dynamical parameter mechanism, is introduced.

Based on a set of specific instances, experiments are carried out, and the experimental results show that the performance of IACO is better than that of two variants of ACO, especially in terms of the convergence speed and swarm diversity. Finally, IACO is used to solve PRD for the oil and gas treatment system of semi-submersible production platform. The simulation results, which include nine pipe paths, demonstrate the practicality and high-efficiency of IACO.

The main contribution of this study is the development of method for solving PRD of a semi-submersible production platform based on the novel mathematical model and the proposed IACO.

With the improvement of consumers' health consciousness, healthy food has attracted great attention in daily consumption. Previous research into the sense of power often distinguishes it into high and low level, ignoring the impact of different construal of power on consumption behaviors. This article divides power into dual construal (responsibility vs opportunity) and aims to examine the differential impacts of the construal of power on healthy food preference.

Two pretests and three formal experiments were conducted to examine the effect of the construal of power on the consumer's healthy food preference, the mediation of self-discipline perception and the moderation of the relative strength of prevention over promotion focus (i.e. RSPPF).

Results indicate that individuals who construe power as responsibility (vs opportunity) exhibit higher self-discipline perception, which in turn leads to greater healthy food preference. However, the main effect above can be weakened among the low-power group. Moreover, the above mediating effect of self-discipline perception is stronger for individuals with higher RSPPF.

First, based on the binary-construal perspective, this study refines the classification of high power and introduces it into the antecedent research of healthy food preference. Second, this paper reveals the self-discipline perception as the inner mechanism underlying the effect of the construal of power on healthy food preference, while RSPPF as the boundary condition for this mediating mechanism. Moreover, this research also provides practical implications for healthy food enterprises that the construal of power, self-discipline perception and regulatory focus should be taken into consideration in advertising design and healthy product promotion.

This paper aims to propose a two-stage vibration isolation system for large airborne equipment to isolate aircraft vibration load.

First, the vibration isolation law of the discrete model of large airborne equipment under different damping ratios, stiffness ratios and mass ratios is analyzed, which guides the establishment of a three-dimensional solid model of large airborne equipment. Subsequently, the vibration isolation transfer efficiency is analyzed based on the three-dimensional model of the airborne equipment, and the angular and linear vibration responses of the two-stage vibration isolation system under different frequencies are studied.

Finally, studies have shown that the steady-state angular vibration at the non-resonant frequency changes little. In contrast, the maximum angular vibration at the resonance peak reaches 0.0033 rad, at least 20 times the response at the non-resonant frequency. The linear vibration at the resonant frequency is at least 2.14 times the response at the non-resonant frequency. Obviously, the amplification factor of linear vibration is less than that of angular vibration, and angular vibration has the most significant effect on the internal vibration of airborne equipment.

The two-stage vibration isolation equipment designed in this paper has a positive guiding significance for the vibration isolation design of large airborne equipment.

Improvement and optimization design of a two-stage vibration isolation system proposed in this paper are conducted to ensure the device of electronic work effective.

The proposed two-stage vibration isolation system of airborne equipment is optimized and parameterized based on multi-objective genetic algorithm.

The results show that compared with initial two-stage vibration isolation system, the angular vibration of the two-stage vibration isolation system becomes 3.55 × 10^-4 rad, which decreases by 89%. The linear isolation effect is improved by at least 67.7%.

The optimized two-stage vibration isolation system effectively improves the vibration reduction effect, the resonance peak is obviously improved and the reliability of the mounting bracket and the shock absorber is highly improved, which provides an analysis method for two-stage airborne equipment isolation design under complex dynamic environment.

This paper aims to study how state ownership influences the innovation process in terms of allocating resources toward searching for new solutions and converting these efforts into economic value. On one hand, deep pockets of the state provide slack resources that may facilitate risk taking and innovation. On the other hand, soft budgets can create incentive problems and dampen the efficient use of resources. The authors suggest how accounting for competitive context can disentangle these countervailing forces.

The authors use a panel of over 240,000 Chinese firms over the years 2004–2008. The broad sample and period afforded substantial variability in terms of state ownership within and across firms. The authors use a two-stage model and a within-firm (i.e. fixed-effects) design, controlling for all time-invariant firm characteristics and the problematic unobserved heterogeneity that can often lead to erroneous inferences. Furthermore, the relatively short window limits the likelihood of time-varying unobserved firm characteristics biasing the empirical results.

The authors found that private-sector competition has the opposite effect on the relationship between state ownership and the second step of the innovation process. In industries where there is robust private-sector competition, state ownership diminishes the firm’s ability to convert R&D efforts into economic value. Private-sector competition competes away any advantages state-owned firms may have in terms of developing or accessing the complementary resources needed for commercialization. Ultimately, the inefficiencies of state ownership in terms of relatively undisciplined selection and monitoring of R&D activities outweigh any potential resource advantages derived from state ownership.

The state remains a prominent player in many economies throughout the world. The authors explored how state ownership of firms influences the resources they expend in searching out new solutions, and their success in converting such resources into economically valuable new products and services. State ownership has potentially countervailing effects on innovation. The authors disentangle these countervailing effects through consideration of how accounting for competitive context could determine whether the beneficial effects of state ownership dominate its detrimental effects for both searching for new solutions and converting these efforts into economically valuable new products. With a focus of market competition as an external force that drives the difference in innovation between SOEs and the private-sector, this study serves as a parallel effort to Jia et al. (2019) who investigate the joint effect of public and corporate governance on SOEs’ innovation performance, and Zhou et al. (2017) who concern the balance of the institution and efficiency logics on the comparative advantage of SOEs over privately owned enterprises in innovation performance.

The supervisory system of modern Chinese companies has basically adopted the supervisory board system of countries of continental law system. Certain disadvantages, however, exist in the system and the purpose of this paper is to identify those disadvantages and suggest changes.

This paper draws upon a consideration of the policy objectives and assesses the practical gaps in implementation through a consideration of case‐studies.

There are many functions and manifest functions of the supervisory board system of modern Chinese companies. Certain disadvantages, however, exist in this system: the postmortem nature of supervision causes the failure of timely supervision, and the externality of supervision leads to information asymmetry. Meanwhile, the functions of supervisory board are weakened by the fact that the law does not impose positive qualification requirements for supervisors and that the law has not laid down specific regulations for the effective deliverance of the company's financial and business information to the supervisors and the supervisory board. In order to guarantee the realization of the functions of the company's supervisory board, we should perfect in legislation the supervisory board system of our country, and at the same time strengthen the construction of company supervisory board system in our country and other relevant supervisory mechanism and supporting systems. Originality/value – This paper presents an analysis of “gaps” in policy implementation and might influence reform in this area.

Based on resource dependence theory and transaction cost economics this study explores how green customer integration (GCI) affects financial performance via information sharing and opportunistic behavior, and the moderating effects of dependence and trust.

This study develops a theoretical model and tests it using data from two-waved survey data of 206 Chinese manufacturers. The hypotheses were tested using hierarchical linear regression analysis.

The results show that GCI has a significant and positive impact on information sharing, but its impact on opportunistic behavior is insignificant. Notably, information sharing has a significant and positive impact on financial performance, while opportunistic behavior has an insignificant impact on financial performance. In addition, dependence negatively moderates the impact of GCI on information sharing and positively moderates the impact of GCI on opportunistic behavior. Trust negatively moderates the impact of GCI on opportunistic behavior.

Although GCI has received widespread attention, how it affects a firm's performance remains unclear. Most previous studies have focused only on its bright side and ignored its dark side. This study highlights how GCI affects financial performance through information sharing and opportunistic behavior, and the moderating effects of dependence and trust. This enriches the understanding of how and under what conditions GCI affects a firm's performance.