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This paper aims to demonstrate low-temperature bonding for piezoelectric materials at temperatures well below the relevant Curie temperatures so as to avoid depolarization of the piezoelectric material during bonding.

Au-coated test samples of lead zirconate titanate (PZT) are bonded to a WC-based resonant backing layer with In–Bi eutectic material in which the In–Bi metal system is a preform or thin, evaporated layers. The bonded samples are characterized using electrical impedance spectroscopy and cross-section microscopy. The first technique verifies the integrity of polarization and reveals the quality of the bondline in a non-destructive manner, particularly looking for voids and delaminations. The latter technique is destructive but gives more precise information and an overview of the structure.

Successful low-temperature (115°C) bonding with intact PZT polarization was demonstrated. The bondlines show a layered structure of Au/Au–In intermetallic compounds (with Bi inclusions)/Au, capable of withstanding temperatures as high as 271°C before remelting occurs. For bonded samples using In–Bi preform, repeatable bonds of high quality (very little voiding) were obtained, but the bonding time is long (1 h or more). For bonded samples using evaporated thin films of In–Bi, bonding can be performed in 30 min, but the process needs further optimization to be repeatable.

Low-temperature solid-liquid interdiffusion (SLID) bonding is a novel technique, merging the fields of low-temperature solder bonding with the SLID/transient liquid phase (TLP) approach, which is normally used for much higher temperatures.

This study addresses the empirical results of the spillover effect with export as the primary economic activity that enhances local businesses' total factor productivity (TFP). A learning mechanism is expected to be generated and used as the basis for the policy implication.

This study adopted the Cobb–Douglas function and multiple estimation approaches, including the generalized method of moments, the Olley–Pakes and the Levinsohn–Petrin estimation techniques. The findings were estimated based on the panel data of a Vietnamese local businesses survey conducted by the General Statistics Office of Vietnam (GSO) from 2010 to 2019.

The results showed that the highest TFP belongs to the businesses in the Southeast region, the Mekong Delta region, the mining industry and the foreign-invested enterprises. The lowest impacted TFP are businesses in the Northwest region and agricultural, forestry and fishery sectors. In addition, the estimated results also show that the positive spillover effect on TFP is shown through forward and backward linkage. The negative spillover effect is expressed through the backward and horizontal channels.

This study offers original empirical evidence on the learning mechanisms via which exports contribute to productivity improvement in a developing Asian economy, so making a valuable contribution to the existing academic literature in this domain. The findings of this research make a valuable contribution to the advancement of understanding on the many ways via which spillover effects manifest such as horizontal, forward, backward and supplied-backward linkage.

The study's findings indicate that it is advisable for governments to give priority to the development and improvement of forward and supply chain linkages between exporters and local suppliers. This approach is recommended in order to optimize the advantages derived from export spillovers. At the organizational level, it is imperative for enterprises to strengthen their technological and managerial skills in order to efficiently incorporate knowledge spillovers that originate from overseas partners and trade counterparts.

This study sheds new evidence on the export spillover effect on productivity in emerging economies, with Vietnam as the case study. The paper contributes to the research's originality by adopting novel methodological aspects to estimate local businesses' impact on total factor productivity.

The peer review history for this article is available at: https://publons.com/publon/10.1108/IJSE-05-2023-0373

The purpose of this paper is to empirically investigate the impact of corruption on foreign direct investment (FDI) and its two major modes of entry: greenfield investment (greenfield) and cross-border mergers and acquisitions (M&As).

Data are collected from 131 countries. Modern econometric techniques, including the generalized method of moments (GMM) estimator, two-stage least square estimator and two-step system GMM estimator, are used to evaluate the impact of corruption on FDI activities.

The empirical results illustrate that corruption is a deterioration factor that significantly hinders FDI inflows. However, this finding turns out to be contradictory when the two major components of FDI – greenfield investment and cross-border M&As – are separately examined. Specifically, while corruption consistently discourages cross-border M&As over time, it appears to exert positive effect on greenfield investments.

This is among the first to empirically examine the impact of corruption on FDI and its modes of entry in a number of countries spanning different time windows. In this sense, this paper also captures the changing nature of societies and economic conditions overtime and, therefore, enable academic researchers, policy-makers and business practitioners to draw broad inferences from the empirical results.

This study aims to examine the relationship between corporate environmental responsibility (CER) practices and different types of innovation carried out by small- and medium-sized enterprises (SMEs) in Vietnam.

The authors employ the bivariate probit model and the two-stage least squares regression model to estimate the effects of CER on process innovation and product innovation of SMEs.

The findings show that while CER is not significantly related to product innovation, it has a positive and significant effect on process innovation. Further analysis indicates that CER engagement increases labor productivity and financial performance of SMEs.

Corporate managers should view implementation of environmental responsibility practices as a strategy to foster process innovation and boost labor productivity and financial performance. For policy makers, government support for firms proactively engaging in CER practices could encourage firms to pursue innovative activities, which are vital to their long-term success as well as to the society's prosperity.

This study makes several important contributions. First, the authors provide new empirical evidence regarding the different effects of engaging in environmentally friendly practices on firm innovation in an under-examined emerging market setting. Second, the authors enrich our understanding of potential benefits of CER implementation. Third, the findings suggest that firm innovation may play a mediating role in the CER–firm performance association.

Employee’s service innovative behavior lays the groundwork for bottom-up innovation and ongoing service improvement in service firms. Therefore, it is vital for service organizations to understand the antecedents of employees service innovative behavior. Drawing upon the social cognitive theory, this study aims to develop a research model that examines the effects of ethical and entrepreneurial leadership on service innovative behavior.

Data were collected from 178 managers and 415 employees working in 178 small- and medium-sized (SME) hotels in Vietnam.

The findings showed that ethical leadership has direct and indirect effects on service innovative behavior, while entrepreneurial leadership only influences service innovative behavior via intrinsic motivation. In addition, trust in leader moderates the effect of intrinsic motivation on service innovative behavior

The study advances current scholarly research on leadership by combining the two areas of entrepreneurial and ethical leadership into one theoretical model and examines how these leadership styles generate hospitality employees’ service innovative behavior through the mediating effect of intrinsic motivation and the moderating effect of trust in leader.

The findings of this research offer significant implications for SME hotels and their managers. In their recruitment processes, hotels should search for particular personality traits, which have been found to predict ethical and entrepreneurial leadership. Hospitality firms also need to encourage communication between leaders and co-workers to enhance employees’ intrinsic motivation.

There are calls for research to examine whether both entrepreneurial and ethical leadership styles can be integrated to enhance employees’ positive outcomes. Evidence about the mechanism linking entrepreneurial and ethical leadership to service innovative behavior is limited. With this stated, the current study makes significant contribution to leadership and innovation literature by filling in these voids.

This study aims to investigate the impact of AI chatbots on customer trust in AI chatbots for hotel services.

The probability sampling method was employed to develop a research sample. The research uses correlation analysis and structural equation modeling to analyze the data of 413 valid observations collected in the structured questionnaire survey in Vietnam.

The paper reports that empathy response, anonymity and customization significantly impact interaction. Empathy response is found to be the strongest influence on interaction. Meanwhile, empathy response and anonymity were revealed to indirectly affect customer trust. This paper also contributes several implications for hotel providers in emerging economies.

To the best of the authors’ knowledge, this is the first study to shed light on the role of AI chatbots in explaining customers’ behavior. The results provide an enhanced understanding of how the AI chatbot system influences customers’ decision-making. It has been used to plan the chatbot application and highlight which implementation issues need the most attention in the hospitality industry.

The purpose of this paper is to demonstrate the uncontrolled vertical takeoff of an insect-mimicking flapping-wing micro air vehicle (FW-MAV) of 12.5 cm wing span with a body weight of 7.36 g after installing batteries and power control.

The forces were measured using a load cell and estimated by the unsteady blade element theory (UBET), which is based on full three-dimensional wing kinematics. In addition, the mean aerodynamic force center (AC) was determined based on the UBET calculations using the measured wing kinematics.

The wing flapping frequency can reach to 43 Hz at the flapping angle of 150°. By flapping wings at a frequency of 34 Hz, the FW-MAV can produce enough thrust to over its own weight. For this condition, the difference between the estimated and average measured vertical forces was about 7.3 percent with respect to the estimated force. All parts for the FW-MAV were integrated such that the distance between the mean AC and the center of gravity is close to zero. In this manner, pitching moment generation was prevented to facilitate stable vertical takeoff. An uncontrolled takeoff test successfully demonstrated that the FW-MAV possesses initial pitching stability for takeoff.

This work has successfully demonstrated an insect-mimicking flapping-wing MAV that can stably takeoff with initial stability.

The literature has demonstrated that lump-sum (LS) outperforms dollar-cost averaging (DCA) in uptrend markets while DCA outperforms LS only when the asset price is mean-reverted or downtrend. To bridge the gap in the literature, this study aims to use both Sharpe ratio (SR) and economic performance measure (EPM) to compare the performance of DCA and LS under both accumulative and disaccumulative approaches when the asset price is simulated to be uptrend.

This study uses both disaccumulative and accumulative approaches to compare DCA with LS and uses both SR and EPM to evaluate their performance when the asset price is simulated to be uptrend. Instead of using the annualized returns that are commonly used by other DCA studies, we compute the holding-period returns in the comparison in this paper.

The simulation shows that no matter which approach is used, DCA outperforms LS in nearly all the cases in the less uptrend markets while DCA still performs better than LS in many cases of the uptrend markets, especially when the market is more volatile and investment horizon is long, regardless which approach the authors used. The authors also find more evidence supporting DCA over LS by using EPM, which is more suitable in the analysis because the returns generated by DCA are positive skewed and flat-tailed that are ignored when SR is used.

The authors conclude that DCA is a better trading strategy than LS for investment even in the uptrend market, especially on high risky assets.

Investors could consider choosing DCA instead of LS as their trading strategy, especially when they prefer long term investment and investing in high-risk assets.

Fund managers could consider recommending DCA to their customers, especially when they prefer long term investment and investing in high-risk assets.

This is the own study and, as far as the authors know, this is the first study in the literature uses both SR and EPM to compare the performance of DCA and LS under both accumulative and disaccumulative approaches when the asset price is simulated to be uptrend.