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The electrical properties of piezoelectric vibrators have a crucial influence on the operating state of ultrasonic motors. In order to solve the problem that the current piezoelectric vibrator generates a large amount of heat during vibration to degrade its performance, which in turn affects the normal operation of ultrasonic motors, this paper prepares a novel piezoelectric vibrator and tests its maximum vibration velocity under the working condition, which is more than twice as much as that of the current commercial PZT-8.

The crystal structures of the samples were analyzed by using an X-ray diffractometer. For microstructure observation, samples were observed by scanning electron microscope (SEM). The quasi-static piezoelectric coefficient meter (ZJ-3AN) was used for piezoelectric measurement. Dielectric properties were measured by utilizing an impedance analyzer (Agilent 4294A) with a laboratory heating unit. Ferroelectric hysteresis loops were obtained using a ferroelectric analyzer (Radiant, Multiferroic 100). A Doppler laser vibrometer (Polytec PSV-300F, Germany) and a power amplifier were used for piezoelectric vibration measurements, during which the temperature rise was determined by an infrared radiation thermometer (Victor 303, China).

The ceramics exhibit enhanced piezoelectric performance at 0.1–0.4 mol% of Yb doping contents. The ceramic of 0.4 mol% Yb reaches the maximal internal bias field and presents a larger mechanical quality factor of 1,692 compared with that of 0.2 mol% Yb-doped ceramic, in spite of a slightly decreased dielectric constant of 439 pC/N, the unit of the piezoelectric constant, which is the ratio of the local charge (pC) to the frontal force (N) and electromechanical coupling coefficient of 0.63. The vibrator with this large mechanical quality factor ceramic displays a vibration velocity of up to 0.81 m/s under the constraint of 20 °C temperature rising, which is much higher than commercial high-power piezoelectric ceramics PZT-8.

The enhanced high-power properties of the piezoelectric vibrator by Yb doping may provide a potential application for the high-performance USM and offer the possibility of long-term stable operation under high power for special equipment like USM. In the subsequent phase of research, the novel PZT-based high-power piezoelectric vibrator can be utilized in the USM, and the motor's performance will be evaluated under aerospace conditions to objectively assess the reliability of the piezoelectric vibrator.

Existing empirical studies emphasize the role of customer preference measurement accuracy (CPMA) on customized product quality while neglecting the role of manufacturing flexibility. However, the rise of web-based technology has highlighted consumer-manufacturer interaction in mass customization (MC). This paper explores the relationships between CPMA, manufacturing flexibility, customer participation and customized product quality, inspired by module decomposition and integration theory.

The study carried out a questionnaire survey of 241 directors who are specifically responsible for MC in the apparel industry in China and tested hypotheses with structural equation modeling (SEM).

CPMA has a direct positive influence on customized product quality and an indirect positive effect through manufacturing flexibility. Also, customer participation after placing an order (CPAPO) has a negative moderating effect on the linkage between CPMA and manufacturing flexibility.

A more dynamic relationship between CPMA and MF can be explored in the future, and the findings can be tested in other industries with more abundant data.

Manufacturing flexibility should be improved along with CPMA in MC. Also, disruptions caused by customer participation in the post-design stage should be noticed. In this context, better consumer service in the early design stage may be one possible solution.

First, the essential but unexplored mediating role of manufacturing flexibility is identified, adding knowledge to the consumer–manufacturer interaction literature in MC production. Second, module decomposition and integration are applied to unify consumers and manufacturers into one empirical model, enriched theoretical research on modular theory. Third, this study opens new discussions on the moderating role of customer participation.

The purpose of this paper is to describe the policy and trends in rural education in China over the past 40 years; and also discuss a number of challenges that are faced by China’s rural school system.

The authors use secondary data on policies and trends over the past 40 years for preschool, primary/junior high school, and high school.

The trends over the past 40 years in all areas of rural schooling have been continually upward and strong. While only a low share of rural children attended preschool in the 1980s, by 2014 more than 90 percent of rural children were attending. The biggest achievement in compulsory education is that the rise in the number of primary students that finish grade 6 and matriculate to junior high school. There also was a steep rise of those going to and completing high school. While the successes in upscaling rural education are absolutely unprecedented, there are still challenges.

This is descriptive analysis and there is not causal link established between policies and rural schooling outcomes.

The authors illustrate one of the most rapid rises of rural education in history and match the achievements up with the policy efforts of the government. The authors also explore policy priorities that will be needed in the coming years to raise the quality of schooling.

This is the first paper that documents both the policies and the empirical trends of the success that China has created in building rural education from preschool to high school during the first 40 years of reform (1978-2018). The paper also documents – drawing on the literature and the own research – the achievements and challenges that China still face in the coming years, including issues of gender, urbanization, early childhood education and health and nutrition of students.

China is the world's largest consumer of pesticides. To increase the use efficiency and achieve more sustainable and environmentally friendly use of pesticides in China, it is crucial to understand why Chinese farmers use such a large amount of pesticides.

The relationship between farm size and pesticide use was investigated by using national household-level panel data from 1995 to 2016.

Farms that are small and fragmented lead to the use of large amounts of pesticides in China. For a given crop type, three factors contribute to a negative relationship between farm size and pesticide use: the spillover effect from the use of pesticides by other farmers in the same village, the level of mechanization and the management ability of farmers. The first two factors play important roles in the cultivation of grain crops, while the last factor is the main reason why farmers with larger plots of land use fewer pesticides in the cultivation of vegetables. In addition, the effect of agricultural machinery services on reducing the use of pesticides is currently limited, and the service system in China is still insufficient, which has been pointed out that it is also due to the prevalence of small and fragmented farms.

The authors investigate and compare the farm size–pesticide use relationship in both grain and cash crop production. Moreover, the authors systematically explore and explain how farm size is related to a reduction in pesticide use in the cultivation of grain crops and cash crops. These results can help to better understand the role of land scale in pesticide use, lay a foundation for the formulation of policies to reduce pesticide use and provide valuable knowledge about pesticide use for other developing countries around the world.

The purpose of this paper is to describe the structure of nonlinear dampers and the dynamic equations, and nonlinear realization principles and optimize the parameters of nonlinear dampers. Using the finite element method to analyze the seismic performance of the frame structure with shock absorber.

The nonlinear shock absorber was installed in a six-storey reinforced concrete frame structure to study its seismic performance. The main structure was designed according to the eight degree seismic fortification intensity, and the time history dynamic analysis was carried out by Abaqus finite element software. EL-Centro, Taft and Wenchuan seismic record were selected to analyze the seismic response of the structure under different magnitudes and different acceleration peaks.

Through the principle study and parameter analysis of the nonlinear shock absorber, combined with the finite element simulation results, the shock absorption performance and shock absorption effect of the nonlinear energy sink (NES) nonlinear shock absorber are given as follows: first, the damping of the NES shock absorber is satisfied, and the linear spring stiffness and nonlinear stiffness of the shock absorber are based on the relationship k1=kn×kl2, so that the spring design length is fixed, and the linear stiffness of the shock absorber can be obtained. The nonlinear shock absorber has the characteristics of high rigidity and frequency bandwidth, so that the frequency is infinitely close to the frequency of the main structure, and when the mass of the shock absorber satisfies between 0.056 and 1, a good shock absorption effect can be obtained, and the reinforced concrete with the shock absorber is obtained. The frame structure can effectively reduce the seismic response, increase the natural vibration period of the structure and reduce the damage loss of the structure. Second, the spacer and each additional shock absorber have a small difference in shock absorption effect. After the shock absorber parameters are accurately calculated, the number of installations does not affect the shock absorption effect of the structure. Therefore, the shock absorber is properly constructed and accurately calculated. Parameters can reduce costs.

New shock absorbers reduce earthquake-induced damage to buildings.

The purpose of this paper is to investigate dynamics of causal interactions and financial risk contagion among BRICS stock markets under rare events.

Two methods are adopted: The new causal inference technique, namely, the Liang causality analysis based on information flow theory and the dynamic causal index (DCI) are used to measure the financial risk contagion.

The causal relationships among the BRICS stock markets estimated by the Liang causality analysis are significantly stronger in the mid-periods of rare events than in the pre- and post-periods. Moreover, different rare events have heterogeneous effects on the causal relationships. Notably, under rare events, there is almost no significant Liang's causality between the Chinese and other four stock markets, except for a few moments, indicating that the former can provide a relatively safe haven within the BRICS. According to the DCIs, the causal linkages have significantly increased during rare events, implying that their connectivity becomes stronger under extreme conditions.

The obtained results not only provide important implications for investors to reasonably allocate regional financial assets, but also yield some suggestions for policymakers and financial regulators in effective supervision, especially in extreme environments.

This paper uses the Liang causality analysis to construct the causal networks among BRICS stock indices and characterize their causal linkages. Furthermore, the DCI derived from the causal networks is applied to measure the financial risk contagion of the BRICS countries under three rare events.

The research effort on entrepreneurship education has been mainly for the higher education settings and on the individual level of analysis. On the contrary, this research urges scholars to expedite attention to the secondary education settings, especially in the emerging economies in Asia and Africa. This paper aims to reveal the existing landscape of literature development on the topic and promote ecological approaches of constructing entrepreneurship education programs in schools. It advocates the “incubator” role of schools for students and the necessity of establishing socially embedded entrepreneurship education as the playground for future entrepreneurs.

This study followed the systematic literature review as its research design. It obtained 1,555 publications from six academic databases and 60 more publications from expert consulting and backward snowballing technique. Data screening resulted in a total of 101 relevant publications with the upper secondary education as their research context. The qualitative integrative synthesis method was then applied to integrate research evidence to the five circles of systems according to Urie Bronfenbrenner’s ecological systems theory.

This study contributes to the entrepreneurship education and youth career development literature, especially in the developing countries. Results discovered that entrepreneurship education programs, when interacting with ecological systems, resulted in training success. The most frequently studied systems were microsystems; here, there was a dominant focus on program-level reporting and analyzing. There was less focus on other systems such as mesosystems, exosystems or macrosystems. Moreover, only one study was associated with chronosystems, suggesting a significant research gap regarding the longitudinal studies. However, this review validated the different approaches to delivering entrepreneurship education in emerging and developed economies.

One limitation of this research lies in the methodology. The inclusion criteria limited the studies to the context of upper secondary education and excluded those of secondary education in general. The sampling method limited the power of this research to analyze and discuss policy-level studies because policies most likely embrace the whole secondary education level as its target. Another limitation is associated with the lack of experimental studies in assessing the comparative advantages of following the ecological approach when constructing entrepreneurship education. It, therefore, remains an undiscussed matter within this study regarding whether following the ecological approach means empirically a better educational choice or not.

This study discusses the implications for policymakers, especially in emerging economies, and suggests that awareness, attention and funding are needed to empower youth entrepreneurship education from an ecological systems view.

To the best of the authors’ knowledge, this research is one of few studies that use the ecological systems theory in the context of entrepreneurship education with the purpose of focusing on environment-level analysis instead of individual-level analysis. Through the systematic literature review, this study proposes an ecological approach to comprehend, guide, evaluate and improve the design and implementation of entrepreneurship education programs in schools based on well-articulated research evidence. The research can inform both researchers and educators by offering a holistic perspective to observe and evaluate entrepreneurship education programs and their levels of social connectedness.

The purpose of this paper is to shed light on the effect of high‐level human capital investment, using tertiary education as the proxy, on the urban‐rural income gap in China.

Using a panel dataset covering 28 provinces of China over the period from 1988 to 2007, this paper employs Hansen's method and two‐step GMM‐SYS estimator to estimate the threshold regression model and the dynamic fixed‐effect panel model, respectively.

The urban‐rural income gap is found to be related to high‐level human capital investment in an inverted U‐shaped pattern with respect to economic development level. The estimated threshold turning point is around 20,000 RMB GDP per capita. This estimate is sufficiently robust to model specifications and variants of the dependent variable.

The authors forecast that high‐level human capital investment could play a role in bridging the urban‐rural income gap at the national level by 2014, when China's GDP per capita assumes an annual growth rate of 7.5 percent.

This, it is believed, is the first research to find an inverted U‐shaped pattern for high‐level human capital investment and urban‐rural income gap nexus in China.

This study aims to propose a vertical coupling dynamic analysis method of vehicle–track–substructure based on forced vibration and use this method to analyze the influence on the dynamic response of track and vehicle caused by local fastener failure.

The track and substructure are decomposed into the rail subsystem and substructure subsystem, in which the rail subsystem is composed of two layers of nodes corresponding to the upper rail and the lower fastener. The rail is treated as a continuous beam with elastic discrete point supports, and spring-damping elements are used to simulate the constraints between rail and fastener. Forced displacement and forced velocity are used to deal with the effect of the substructure on the rail system, while the external load is used to deal with the reverse effect. The fastener failure is simulated with the methods that cancel the forced vibration transmission, namely take no account of the substructure–rail interaction at that position.

The dynamic characteristics of the infrastructure with local diseases can be accurately calculated by using the proposed method. Local fastener failure will slightly affect the vibration of substructure and carbody, but it will significantly intensify the vibration response between wheel and rail. The maximum vertical displacement and the maximum vertical vibration acceleration of rail is 2.94 times and 2.97 times the normal value, respectively, under the train speed of 350 km·h⁻¹. At the same time, the maximum wheel–rail force and wheel load reduction rate increase by 22.0 and 50.2%, respectively, from the normal value.

This method can better reveal the local vibration conditions of the rail and easily simulate the influence of various defects on the dynamic response of the coupling system.

This study investigates how food safety trust works as a critical moderator in the Chinese online fresh agricultural market based on an extended technology acceptance model.

The authors propose a research model that integrates attributes from the technology acceptance model, perceived product quality, logistics service quality, risk, and food safety trust. Structural equation modeling was applied to estimate the causal relationships using data from 851 Chinese customers.

The results indicated that perceived usefulness, product quality, and logistics service quality significantly enhance Chinese customers' intention to shop online for fresh agricultural products. Further, the positive effects increase when customer trust in food safety changes from low to high. In contrast, perceived risk reduces Chinese customers' willingness to engage in online shopping, but the negative influence is weaker for customers with high trust in food safety than for those with low trust. However, perceived ease of use plays an insignificant role in predicting online purchase intention and the impact does not vary depending on food safety trust.

This study suggests managers should consider the important moderating role of food safety trust to make effective strategies for fresh agricultural e-commerce development in China.