Analysis of the thermal effects during the packaging process or in the actual operating environment is necessary to develop small monolithic integrated sensing chips with…
Abstract
Purpose
Analysis of the thermal effects during the packaging process or in the actual operating environment is necessary to develop small monolithic integrated sensing chips with heterogeneous integration. The use of multiple layers and various materials in monolithic integrated sensing chips addresses the coefficient of thermal expansion (CTE) mismatch issue. The purpose of this study is to focus on the residual stress analysis of the shielding electrode, which is a metal film that prevents pull-in of proof-mass during anodic bonding in microelectromechanical system (MEMS) chips with pressure sensors embedded in an accelerometer.
Design/methodology/approach
The finite element model of the chip was built by the commercial software ANSYS, and the residual stress was evaluated during the die attachment process for the shielding electrode. Various shielding electrode materials and a proposed design with a keep-out zone to reduce the residual stress are discussed, with a focus on the relationship between the geometric parameters of the chip and the residual stress for copper shielding electrodes of different thicknesses.
Findings
The results of the finite element analysis showed that the use of polysilicon as a shielding electrode in the proposed design generated the lowest residual stress because of its low CTE. The maximum stresses in both of in-plane and out-of-plane directions in the finite element model were reduced by keep-out zone design for the proposed design of the copper shielding electrode, and had 11 times reduction in out-of-plane direction especially, according to the nonlinear analysis as the stress concentration point in the shielding electrode moved. Moreover, the design with a thinner shielding electrode, thinner glass substrate and higher CTE of the glass substrate also lowered the maximum von Mises stress. On the other hand, the stress level during the operating temperature, without considering residual stress, overestimated up to five times in the proposed design.
Originality/value
In this study, valuable suggestions are proposed for the design of chips with pressure sensors embedded in accelerometers.
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Hung‐Yi Lu, Hsin‐Ya Hou, Tzong‐Horng Dzwo, Yi‐Chen Wu, James E. Andrews, Shao‐Ting Weng, Mei‐Chun Lin and Jun‐Ying Lu
The melamine milk scandal caused a crisis of confidence in food containing dairy products. The purpose of this paper is to explore the determinants of precautionary behaviour to…
Abstract
Purpose
The melamine milk scandal caused a crisis of confidence in food containing dairy products. The purpose of this paper is to explore the determinants of precautionary behaviour to avoid food containing dairy products among Taiwanese college students.
Design/methodology/approach
Of the total respondents selected using a multistage cluster sampling plan, 1,213 respondents completed the questionnaire.
Findings
The survey results showed that subjective norms, attitude, perceived behavioural control, attention to news, and perceived credibility of information are significantly associated with the intention to take precautionary behaviour.
Originality/value
The paper developed a modified theory of planned behaviour (TPB) that focused on attention and perceived credibility of milk scandal‐related information as additional determinants of precautionary behaviour to avoid food containing dairy products. The inclusion of attention and perceived credibility of information constructs enabled a better model fit than that of the TPB model.
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This paper aims to report on an investigation into ways in which end‐users perceived citation database interfaces, especially citation database interfaces' usability.
Abstract
Purpose
This paper aims to report on an investigation into ways in which end‐users perceived citation database interfaces, especially citation database interfaces' usability.
Design/methodology/approach
The investigation used the Technology Acceptance Model (TAM) constructs of usefulness and ease of use to assess acceptance of citation database interfaces by university graduate students. A structural equation model was used to fit and validate the Citation Database Interface Acceptance Model (CDIAM).
Findings
Causal relationships between the constructs considered by the CDIAM were well supported, accounting for 95 per cent of total variance in citation database interface acceptance and usage. The study concluded that perceived usefulness, and not ease of use of citation database interface, is a key determinant of their acceptance and usage. The results of the construct measurement for perceived usefulness and ease of use in this research are quite consistent with the results reported in recent research.
Originality/value
Study findings may help to evaluate human‐computer interaction using the MIS‐proven TAM and improve usability of the citation database system.
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Shih-Liang Chao, Chin-Shan Lu, Kuo-Chung Shang and Ching-Chiao Yang
Ming-Hui Liu, Jianbin Xiong, Chun-Lin Li, Weijun Sun, Qinghua Zhang and Yuyu Zhang
The diagnosis and prediction methods used for estimating the health conditions of the bearing are of great significance in modern petrochemical industries. This paper aims to…
Abstract
Purpose
The diagnosis and prediction methods used for estimating the health conditions of the bearing are of great significance in modern petrochemical industries. This paper aims to discuss the accuracy and stability of improved empirical mode decomposition (EMD) algorithm in bearing fault diagnosis.
Design/methodology/approach
This paper adopts the improved adaptive complementary ensemble empirical mode decomposition (ICEEMD) to process the nonlinear and nonstationary signals. Two data sets including a multistage centrifugal fan data set from the laboratory and a motor bearing data set from the Case Western Reserve University are used to perform experiments. Furthermore, the proposed fault diagnosis method, combined with intelligent methods, is evaluated by using two data sets. The proposed method achieved accuracies of 99.62% and 99.17%. Through the experiment of two data, it can be seen that the proposed algorithm has excellent performance in the accuracy and stability of diagnosis.
Findings
According to the review papers, as one of the effective decomposition methods to deal with nonlinear nonstationary signals, the method based on EMD has been widely used in bearing fault diagnosis. However, EMD is often used to figure out the nonlinear nonstationarity of fault data, but the traditional EMD is prone to modal confusion, and the white noise in signal reconstruction is difficult to eliminate.
Research limitations/implications
In this paper only the top three optimal intrinsic mode functions (IMFs) are selected, but IMFs with less correlation cannot completely deny their value. Considering the actual working conditions of petrochemical units, the feasibility of this method in compound fault diagnosis needs to be studied.
Originality/value
Different from traditional methods, ICEEMD not only does not need human intervention and setting but also improves the extraction efficiency of feature information. Then, it is combined with a data-driven approach to complete the data preprocessing, and further carries out the fault identification and classification with the optimized convolutional neural network.
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Shiang-Lih Chen McCain, Jeffrey Lolli, Emma Liu and Li-Chun Lin
The study aims to analyze guest comments on the Uber Eats food delivery app (FDA) in the USA during the April–June 2020 COVID-19 pandemic lockdown period. Three aspects…
Abstract
Purpose
The study aims to analyze guest comments on the Uber Eats food delivery app (FDA) in the USA during the April–June 2020 COVID-19 pandemic lockdown period. Three aspects influencing customer satisfaction with the FDA were evaluated in this study: (1) performance on the app, (2) product quality and (3) service quality.
Design/methodology/approach
One thousand customer comments posted on the Uber Eats Google Play app from April 1 to June 30, 2020 were analyzed in this study. The text mining technique was applied to discover the hidden, but meaningful patterns from the unstructured text. Content analysis was applied to systematically analyze the text into organized categories and themes.
Findings
Among the three dimensions evaluated in this study, the most important dimension regarding customers' perceptions toward the FDA was the service quality dimension (40.02%), followed by the FDA's performance dimension (39.43%) and the product quality dimension (20.54%) was least important. Additionally, customers' perceptions towards the three dimensions were all unfavorable and there were more negative comments than the positive comments: FDAs (P/N = 0.728), product quality (P/N = 0.60) and service quality (P/N = 0.865).
Originality/value
Previous studies investigating FDAs assessed solely the performance of the app. However, customers' experience of a food delivery service is comprised of multiple components including the app, the restaurant and the delivery driver. To fill the void, this study evaluated a third-party app performance, product quality and service quality to capture the totality of customers' food delivery service experience.
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Yi-chun Lin and Angela Shin-yih Chen
Career plateau is a major concern for many seasoned employees because they often stay in the same position longer than expected and over time begin to lack job challenges. This…
Abstract
Purpose
Career plateau is a major concern for many seasoned employees because they often stay in the same position longer than expected and over time begin to lack job challenges. This phenomenon is now considered a normal stage in career development. The purpose of this study is to test the effects of two types of career plateau: hierarchical and job content on career commitment (career identity, career insight and career resilience), along with the mediating effect of perceived external employability. We also determined in the moderated mediation model if Super's (1957) three career stages amplify and attenuate the indirect effect of hierarchical/job content plateau on career commitment (career identity, career insight, career resilience) via perceived external employability.
Design/methodology/approach
We tested the hypotheses with survey data collected from a convenience sample of 472 white-collar full-time employees who also studied in the MBA and continuing education program in five large universities in Taiwan (77% return rate).
Findings
The mediation model result showed that perceived external employability partially and negatively mediated the influence of hierarchical plateaus on career commitment (career identity, career insight and career resilience). Perceived external employability partially and negatively mediated the influence of job content plateaus on career identity and career insight but fully and negatively mediated on career resilience. The result of the moderated mediation model also demonstrated that only employees in the trial stage had influences on the mediation relationships among the hierarchical plateau, perceived external employability and career commitment with its two dimensions of career identity and career insight only other than those in the stabilization and maintenance stages.
Practical implications
The findings of this study can benefit career management scholars and practitioners since they promote a better understanding of the career management practices that are relevant for seasoned employees who are valued for their knowledge, experience and expertise when encountering the three career stages.
Originality/value
Drawing on the conservation of resources (COR) theoretical perspective, we fill the gap in the literature by proposing perceived external employability as a mediator in the link between career plateau and career commitment and generalize the results to plateaued employees at the different career stages.
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Chern Sheng Lin, Chang-Yu Hung, Chung Ting Chen, Ke-Chun Lin and Kuo Liang Huang
This study aims to present an optical alignment and compensation control of die bonder for chips containing through-silicon vias and develop three-dimensional integrated circuit…
Abstract
Purpose
This study aims to present an optical alignment and compensation control of die bonder for chips containing through-silicon vias and develop three-dimensional integrated circuit stacked packaging for compact size and multifunction.
Design/methodology/approach
The machine vision, optical alignment method and sub-pixel technology in dynamic imaging condition are used. Through a comparison of reference image, the chip alignment calibration can improve machine accuracy and stability.
Findings
According to the experimental data and preliminary results of the analysis, accuracy can be achieved within the desired range, and the accuracy is much better than traditional die bonder equipment. The results help further research in die bonder for chips containing through-silicon vias.
Originality/value
In subsequent testing of the chip, the machine can simultaneously test multiple chips to save test time and increase productivity.
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Yi-chun Lin, Angela Shin-yih Chen and Yu-ting Lai
The purpose of this paper is to identify the impact of career plateau (hierarchical and job-content plateau) on internal employability, and to investigate psychological contract…
Abstract
Purpose
The purpose of this paper is to identify the impact of career plateau (hierarchical and job-content plateau) on internal employability, and to investigate psychological contract breach as a moderator on the relationship between career plateau (hierarchical and job-content plateau) and internal employability.
Design/methodology/approach
Data were collected by distributing paper-based questionnaires to 521 workers in private banking sectors in Taiwan. Hierarchical regression analysis was used to examine the results of the relationships.
Findings
The results supported the idea that career plateau (hierarchical and job-content plateaus) could be a significant antecedent of internal employability. Psychological contract breach significantly moderated the negative relationship between career plateau (hierarchical and job-content plateau) and internal employability. Specifically, the negative relationship between career plateau and internal employability will be stronger for employees who perceive a higher level of psychological contract breach.
Practical implications
These findings can help human resource practitioners gain a better understanding of the value of applicable approaches as an influence on a plateaued employee’s perception of internal employability, and to facilitate a positive employer–employee relationship, which could foster both a successful career for an individual and a prosperous performance for the organization that employs them.
Originality/value
Career plateau have been aroused variety issues in HR practice, but employability and psychological contract breach have barely been discussed with career plateau. This study empirically establishes the correlation between career plateau and internal employability as well as shown that psychological contract breach would decrease the plateaued individual’s willingness to stay in the current organization. Thus, the career plateau may provide organizations with a helpful perspective on one’s career development. Building substantial relationships between employees and employers lead to better human capital for organizations as it deals with rapidly changes in the real world.
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Dongdong Song, Wenxiang Qin, Qian Zhou, Dong Xu and Bo Zhang
The anticorrosion coatings used in marine and atmospheric environment are subjected to many environmental factors. And the aging failure has been puzzling researchers. The purpose…
Abstract
Purpose
The anticorrosion coatings used in marine and atmospheric environment are subjected to many environmental factors. And the aging failure has been puzzling researchers. The purpose of this study is to find the correlation between the initial aging of epoxy coatings and the typical marine atmospheric environmental factors.
Design/methodology/approach
The epoxy coatings were subjected to a one-year exposure in three typical marine atmospheres. Meanwhile, principal component analysis, linear regression and Spearman and gray correlation analysis were applied to quantify the environmental characteristics and establish correlations with the coating aging.
Findings
The results indicate that the coating will undergo macroscopic fading and chalking upon exposure to the marine atmosphere, while microscopic examination reveals holes, cracks and partial peeling. The adhesion performance and electrochemical properties of the coating deteriorated with prolonged exposure, coating aging mainly occurs with the generation of O-H bonds and the breakage of molecular chains such as C-N and C-O-C. The coating was most deeply aged after exposure to the Xisha, followed by Zhoushan and finally Qingdao. Environmental factors affect the photooxidative aging and hydrolytic degradation processes of coatings and thus coating aging. To further demonstrate the correlation between environmental factors and coating aging, principal component analysis was used. The correlation model between environmental factors and coating aging was subsequently obtained. The correlation model between the rate of coating adhesion loss (E) and the comprehensive evaluation parameter of environmental factors (Z) is expressed as E = 0.142 + 0.028Z. Meanwhile, the Spearman correlation analysis and gray correlation method were used to investigate the impact of each environmental factor on coating aging. Solar irradiation, relative humidity and wetting time have the highest correlation with coating aging, which are all above 0.8 and have the greatest influence on coating aging; wind speed and temperature have the smallest correlation with coating aging, which are about 0.6 and have the least influence on coating aging.
Originality/value
This paper establishes a correlation between typical marine environmental factors and coating aging performance, which is crucial for predicting the service life of other coatings in diverse environments.