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The purpose of this paper is to reveal the changing role of the parameters of the DDGM(1,1) model after multiple transformations in the modeling sequence.

This paper considers DDGM(1,1) model as the research object, adopts the parameter packet technique to analyze the influence of multiple transformations on the modeling accuracy of this model and discusses the quantitative relation of model parameters as multiple transformations in system’s characteristic sequences.

The results of numerical calculation show that the modeling accuracy of DDGM(1,1) model is not affected by multiple transformations in the characteristics sequence of systems.

The paper succeeds in realizing the properties of DDGM(1,1) model by using the method of multiple transformations, which is helpful to understand the modeling mechanism and expand the application range of DDGM(1,1) model.

The purpose of this paper is to study the properties of derived grey verhulst prediction model with multiplication transformation and reduce its modeling complexity.

The paper discussed the parameter characteristics of grey derived verhulst model under multiple transformation, and demonstrated its effect on its simulative value and predictive value by investigating the multiple transformation acting on the raw data sequence of this grey model. The parameter characteristics of this model under multiple transformations and its effect of the simulation value and forecasting value are analyzed by studying the properties of multiply transformation of this model.

The research finding shows that the modeling accuracy of derived grey verhulst model is in no relation to multiple transformations.

The above results imply that the data level can be reduced; the process of building derived grey verhulst model can be simplified; but the simulative and predictive accuracy of this model remain unchanged.

The paper succeeds in realising the properties of derived grey verhulst model by using the method of multiplication transformation, which is helpful to understand the modeling mechanism and expand the application range of derived grey verhulst model.

This paper aims to investigate the friction noise properties of M50 matrix curved microporous channel composites filled with solid lubricant Sn-Ag-Cu (MS).

Pure M50 (MA) and MS are prepared by selective laser melting and vacuum-pressure infiltration technology. The tribological and friction noise properties of MA and MS are tested through dry sliding friction and then the influential mechanism of surface wear sate on friction noise is investigated by analyzing the variation law of noise signals and the worn surface characteristics of MS.

Experimental results show that the friction noise sound pressure level of MS is only 75.6 dB, and it mainly consists of low-frequency noise. The Sn-Ag-Cu improves the surface wear state, which reduces self-excited vibration of the interface caused by fluctuation of friction force, leading to the decrease of friction noise.

This investigation is meaningful to improve the tribological property and suppress the friction noise of M50 bearing steel.

This paper aims to explore the damage mechanism of a lubricating film on the worn surface of solid self-lubricating composites under different loads.

By comparing the actual stress with the strength, it is possible to determine the approximate wear state of the lubricating film. To prove the validity of the mathematical model that can predict the initiation of micro cracks or even the failure of the lubricating film, M50-5 Wt.% Ag self-lubricating composites (MA) was prepared. Tribological tests of the composites against Si₃N₄ ceramic balls were conducted at room temperature from 2 to 8 N. The electron probe microanalysis images of the lubricating film verify the wear state of the lubricating film.

The study found that the back edge of the contact area is the most vulnerable to destruction. The tensile stress and the equivalent shear stress have a positive correlation with load and friction coefficient. When the load is 4 N, an intact lubricating film covers the worn surface because the tensile stress and the equivalent shear stress are below the tensile strength and the shear strength, respectively; under other working conditions, the lubricating film is destroyed.

This paper has certain theoretical guidance for the study of tribological properties of solid self-lubricating composites. Moreover, this mathematical model is appropriate to be applied for the other composites.

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.

The purpose of this paper is to investigate the relationship between investors' divergence of opinions and the asset prices of foreign stocks and also examine the effect of home market country-level factors on the influence of divergency of opinions on stock price.

The authors employ panel data estimation with fixed effects to examine the host market response in divergent opinions to the earnings announcements. The paper uses the American Depositary Receipts (ADRs) of 42 countries from 1985 to 2011.

The authors find a negative relationship between differences of opinions and excess quarterly earnings announcement returns, and investors do process information asymmetrically based on good and bad earnings shocks. In addition, the authors find the negative relationship between divergent opinions and excess earnings announcement returns in ADRs is more pronounced in countries with short-sales restrictions, while other home-market country-level factors – the enforcement of insider trading law, legal origin, investor protection and rating on accounting standard – do not influence the relationship between investors' divergency of opinion and stock returns.

This paper is among the first to bring asymmetric effects on convergence in Miller framework and enhance the understanding of price convergence documented in Miller (1977). In addition, this study incorporates home-market country-level factors in explaining the relationship between investors' divergency of opinions and stock returns.

Despite previous research highlighting the consequences of facades of conformity (FOC) on attitudes, emotions and feelings, little is known about their negative effects on behaviors. This study draws on the job stress process model to examine the association between FOC and cyberloafing and explores how anxiety functions as an underlying mechanism affecting cyberloafing.

A total of 185 employees from Chinese organizations participated in a two-wave questionnaire survey.

The study found a positive relationship between FOC and cyberloafing and noted that anxiety mediates this relationship. The research also identified that performance–avoidance goal orientation moderates the relationship between FOC and anxiety, as well as the indirect effects of the FOC–cyberloafing relationship via anxiety.

The research findings demonstrate that FOC is positively associated with anxiety and cyberloafing. The disruptive nature of FOC in the workplace has been revealed. Furthermore, this study provides valuable suggestions for managers on how to reduce employee FOC and cyberloafing.

Using the job stress process model, this study investigates whether (main effect), how (a mediating mechanism) and when (boundary condition) FOC drives cyberloafing, deepening the understanding of the relationship between FOC and cyberloafing.

Low levels of human capital in rural China are rooted in the poor schooling outcomes of elementary school students. The purpose of this paper is to provide insight into the distribution of academic performance in rural China and identify vulnerable groups.

The authors draw on a data set of 25,892 observations constructed from 11 school-level surveys spanning nine provinces and one municipality in China conducted from 2013 to 2015.

The authors find that the distribution of academic performance is uneven across provinces and subgroups. In general, male students, Han, living in richer counties, living with their parents and studying in rural public schools do better academically than female students, non-Han, living in poorer counties, left behind and studying in private migrant schools in cities.

Using the results of this study, policymakers should be able to better target investments into rural education focusing on at risk subpopulations.

With limited data sources, the research on the academic performance of students in rural China is largely absent. The findings of this study help to fill the gaps in the literature base.

This paper aims to examine how emotions affect consumers' food choices and food preparation activities during stressful periods, using the context of the coronavirus disease 2019 (COVID-19) outbreak in China.

This study used an online survey, with a sample of 1,050 individuals from 32 regions in China. Multi-regression and mediation models were used to test the relationships among perceived knowledge, emotions and food behaviors.

The results show that positive emotions positively affect healthy food consumption and engagement in food preparations. In contrast, negative emotions contribute to an increase in indulgent food consumption and quick-and-easy meal preparations. Increased knowledge of the current situation can enhance positive emotions and thus promote healthy food behaviors. Lacking knowledge may result in unhealthy food behaviors through negative emotions.

This study contributes to the understanding of emotions and food behaviors by examining the effects of both negative and positive emotions in the general population, exploring a wider constellation of food behaviors and identifying perceived knowledge as an important antecedent to emotions' effects on food behaviors. Implications for consumers and public policy are offered.

This paper aims to study the impact of the interaction effects between live-streaming marketing and clothing type on consumers' intention to purchase clothing, and the mediating effect of internalization and identification on the relationship between them.

This paper conducts a scenario experiment to 486 consumers who had experience in purchasing clothing on the live-streaming platform and employs the analysis of variance, structural equation model and multivariate regression model.

Our findings reveal that professional live-streaming marketing (PLSM) can better stimulate consumers' intention to purchase formal clothing than entertainment live-streaming marketing (ELSM) does. Compared with PLSM, ELSM can better stimulate consumers' intention to purchase casual clothing. When PLSM promotes formal clothing, it triggers the internalization mechanism of consumers, so as to improve their purchase intention. When ELSM promotes casual clothing, it triggers consumers' identification mechanism, so as to improve their purchase intention.

This paper helps to identify the differences in the impact of different types of live-streaming marketing on consumers' intention to purchase different types of clothing, as well as the mediating role of internalization and identification mechanisms. This paper provides a theoretical reference for clothing firms to strategically select the appropriate type of live-streaming marketing.