Chongbin Hou, Yang Qiu, Xingyan Zhao, Shaonan Zheng, Yuan Dong, Qize Zhong and Ting Hu
By investigating the thermal-mechanical interaction between the through silicon via (TSV) and the Cu pad, this study aimed to determine the effect of electroplating defects on the…
Abstract
Purpose
By investigating the thermal-mechanical interaction between the through silicon via (TSV) and the Cu pad, this study aimed to determine the effect of electroplating defects on the upper surface protrusion and internal stress distribution of the TSV at various temperatures and to provide guidelines for the positioning of TSVs and the optimization of the electroplating process.
Design/methodology/approach
A simplified model that consisted of a TSV (100 µm in diameter and 300 µm in height), a covering Cu pad (2 µm thick) and an internal drop-like electroplating defect (which had various dimensions and locations) was developed. The surface overall deformation and stress distribution of these models under various thermal conditions were analyzed and compared.
Findings
The Cu pad could barely suppress the upper surface protrusion of the TSV if the temperature was below 250 ?. Interfacial delamination started at the collar of the TSV at about 250 ? and became increasingly pronounced at higher temperatures. The electroplating defect constantly experienced the highest level of strain and stress during the temperature increase, despite its geometry or location. But as its radius expanded or its distance to the upper surface increased, the overall deformation of the upper surface and the stress concentration at the collar of the TSV showed a downward trend.
Originality/value
Previous studies have not examined the influence of the electroplating void on the thermal behavior of the TSV. However, with the proposed methodology, the strain and stress distribution of the TSV under different conditions in terms of temperature, dimension and location of the electroplating void were thoroughly investigated, which might be beneficial to the positioning of TSVs and the optimization of the electroplating process.
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Yanfei Yang, Xiaobo Wang, Sen Mei, Xing Zhu, Shiqiang Chen, Peng Xiong, Zhihai Hu, Kun Xiong and Dong Song Yuan
The purpose of this paper is to investigate the tribological performance and mechanisms of BN/calcium borate nanocomposites (BCBNs) as additives in lubricating oil.
Abstract
Purpose
The purpose of this paper is to investigate the tribological performance and mechanisms of BN/calcium borate nanocomposites (BCBNs) as additives in lubricating oil.
Design/methodology/approach
BCBNs were prepared by heterogeneous deposition method. And the morphology and structure of samples were analysed by transmission electron microscopy, Fourier transform infrared spectra and X-ray powder diffraction pattern. The maximum non-seizure load (PB) of samples was tested using four-ball friction tester. The average friction coefficients and wear tracks were obtained. In addition, tribological mechanism was also investigated using optical microscope, energy dispersive spectroscopy and X-ray photoelectron spectroscope.
Findings
It was found that the nanocomposites present core-shell nanostructure with the thickness of shell around 12 nm and the diameter of particles 100-200 nm, and tribological tests indicate that the PB value of BCBNs was increased by 113 per cent, whereas the average friction coefficient was decreased by 23.6 per cent and the bloom’s wear area was also decreased by 25.2 per cent.
Originality/value
This paper involves investigation on tribological properties and mechanism of the BCBNs with core-shell structure.
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Keywords
Kaifeng Jiang, Si Yuan and Qinyan Xing
This paper aims to propose a new adaptive strategy for two-dimensional (2D) nonlinear finite element (FE) analysis of the minimal surface problem (MSP) based on the element energy…
Abstract
Purpose
This paper aims to propose a new adaptive strategy for two-dimensional (2D) nonlinear finite element (FE) analysis of the minimal surface problem (MSP) based on the element energy projection (EEP) technique.
Design/methodology/approach
By linearizing nonlinear problems into a series of linear problems via the Newton method, the EEP technique, which is an effective and reliable point-wise super-convergent displacement recovery strategy for linear FE analysis, can be directly incorporated into the solution procedure. Accordingly, a posteriori error estimate in maximum norm was established and an adaptive 2D nonlinear FE strategy of h-version mesh refinement was developed.
Findings
Three classical known surfaces, including a singularity problem, were analysed. Moreover, an example whose analytic solution is unavailable was considered and a comparison was made between present results and those computed by the MATLAB PDE toolbox. The results show that the adaptively-generated meshes reflect the difficulties inherent in the problems and the proposed adaptive analysis can produce FE solutions satisfying the user-preset error tolerance in maximum norm with a fair adaptive convergence rate.
Originality/value
The EEP technique for linear FE analysis was extended to the nonlinear procedure of MSP and can be expected to apply to other 2D nonlinear problems. The employment of the maximum norm makes point-wisely error control on the sought surfaces possible and makes the proposed method distinguished from other adaptive FE analyses.
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Yuxue Sheng and James P. LeSage
We are interested in modeling the impact of spatial and interindustry dependence on firm-level innovation of Chinese firms The existence of network ties between cities imply that…
Abstract
We are interested in modeling the impact of spatial and interindustry dependence on firm-level innovation of Chinese firms The existence of network ties between cities imply that changes taking place in one city could influence innovation by firms in nearby cities (local spatial spillovers), or set in motion a series of spatial diffusion and feedback impacts across multiple cities (global spatial spillovers). We use the term local spatial spillovers to reflect a scenario where only immediately neighboring cities are impacted, whereas the term global spatial spillovers represent a situation where impacts fall on neighboring cities, as well as higher order neighbors (neighbors to the neighboring cities, neighbors to the neighbors of the neighbors, and so on). Global spatial spillovers also involve feedback impacts from neighboring cities, and imply the existence of a wider diffusion of impacts over space (higher order neighbors).
Similarly, the existence of national interindustry input-output ties implies that changes occurring in one industry could influence innovation by firms operating in directly related industries (local interindustry spillovers), or set in motion a series of in interindustry diffusion and feedback impacts across multiple industries (global interindustry spillovers).
Typical linear models of firm-level innovation based on knowledge production functions would rely on city- and industry-specific fixed effects to allow for differences in the level of innovation by firms located in different cities and operating in different industries. This approach however ignores the fact that, spatial dependence between cities and interindustry dependence arising from input-output relationships, may imply interaction, not simply heterogeneity across cities and industries.
We construct a Bayesian hierarchical model that allows for both city- and industry-level interaction (global spillovers) and subsumes other innovation scenarios such as: (1) heterogeneity that implies level differences (fixed effects) and (2) contextual effects that imply local spillovers as special cases.
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Jing Jiang, Yuan Yuan, Yanan Dong and Huijuan Dong
This study aims to examine the joint impact of customer mistreatment (external stressor) and team performance pressure (internal stressor) on employees’ proactive customer service…
Abstract
Purpose
This study aims to examine the joint impact of customer mistreatment (external stressor) and team performance pressure (internal stressor) on employees’ proactive customer service performance (PCSP) using the stressor-emotion model.
Design/methodology/approach
The sample consisted of 220 employees and 54 branch leaders from a large restaurant chain in China. This study conducted a multi-time and multi-source design study using Mplus 7.4 to examine the hypotheses.
Findings
Customer mistreatment has a positive effect on employees’ emotional exhaustion, which further reduces PCSP. Team performance pressure strengthens the dysfunctional effect of customer mistreatment on emotional exhaustion, whereas leaders’ positive affective presence mitigates the negative relationship between emotional exhaustion and PCSP.
Originality/value
This study investigates how internal and external stressors jointly affect employees’ PCSP. Thus, it provides a comprehensive perspective of employee stress management and active service management for organization managers.
研究目的
基于压力源-情绪模型, 本研究旨在了解客户不当对待(外部压力源)和团队绩效压力(内部压力源)如何共同影响员工的主动对客服务绩效。
设计/方法/方法
我们的样本来自中国一家大型连锁餐厅的220名员工和54名分店负责人。我们进行了多时间和多来源设计, 并采用Mplus 7.4检验所有假设。
研究结果
客户不当对待会导致员工情绪衰竭, 进而降低主动对客服务绩效。团队绩效压力加强了客户不当对待对员工情绪衰竭的消极影响,而领导者积极情感体现可以减弱员工情绪衰竭对其员工主动对客服务绩效的负面影响。
原创性
本文的贡献是全面探讨内部和外部压力源如何共同影响员工的主动对客服务绩效, 从而为组织管理者提供一个更全面的员工压力管理和主动服务管理的视角。
Objetivo
Este estudio examina el impacto conjunto de los abusos de los clientez (estresor externo) y la presión sobre el rendimiento del equipo (estresor interno) en el rendimiento proactivo del servicio al cliente (PCSP) de los empleados utilizando el modelo estresor-emoción.
Diseño/metodología/enfoque
Nuestra muestra está formada por 220 empleados y 54 jefes de establecimientos pertenecientes a una gran cadena de restaurantes de China. Realizamos un diseño multitemporal y multifuente con Mplus 7.4 para examinar todas las hipótesis.
Resultados
Los abusos de los clientes tienen un efecto positivo sobre el agotamiento emocional de los empleados, lo que reduce aún más la PCSP. La presión sobre el rendimiento del equipo refuerza el efecto disfuncional del abuso de los clientes sobre el agotamiento emocional, mientras que la presencia afectiva positiva de los líderes mitiga la relación negativa entre el agotamiento emocional y la PCSP.
Originalidad/valor
Este artículo contribuye a investigar cómo los factores estresantes internos y externos afectan conjuntamente a la PCSP de los empleados. Proporciona una perspectiva más completa de la gestión del estrés de los empleados y de la gestión activa de los servicios para los directivos de las organizaciones.
Details
Keywords
- Customer mistreatment
- Employees’ emotional exhaustion
- Proactive customer service performance
- Team performance pressure
- Leaders’ positive affective presence
- 顾客不当对待、员工情绪衰竭、主动对客服务绩效、团队绩效压力、领导者积极情感体现
- Abuso del cliente
- Agotamiento emocional de los empleados
- Rendimiento proactivo del servicio al cliente
- Presión sobre el rendimiento del equipo
- Presencia afectiva positiva de los líderes
Haohan Sun and Si Yuan
An improved adaptive finite element analysis based on local error estimate is proposed via the element energy projection (EEP) technique. This paper aims to discuss the…
Abstract
Purpose
An improved adaptive finite element analysis based on local error estimate is proposed via the element energy projection (EEP) technique. This paper aims to discuss the aforementioned idea.
Design/methodology/approach
The computational region for a posteriori error estimation based on EEP method is further confined to a critical set of local elements generated in the previous adaptive step, enhancing efficiency while maintaining accuracy. The adaptive procedure incorporated with hierarchical mesh refinement is then developed.
Findings
The effectiveness of the improved error estimation of the overall adaptive analysis is confirmed by several benchmark examples. The results show that the shrinkage of the local computational region has little negative influence on the accuracy of a posteriori error estimation, thus yielding an improved adaptive procedure with simplified logic and reduced cost.
Originality/value
By localizing the computational region for error estimation, two crucial but cumbersome tricks, i.e. treatments of virtual elements and hanging nodes, are removed, giving the proposed approach full clarity and flexibility. The improved adaptive procedure characterizes simpler and faster computational algorithm and can produce results with required accuracy measured in maximum norm.
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Haohan Sun and Si Yuan
A general strategy is developed for adaptive finite element (FE) analysis of free vibration of elastic membranes based on the element energy projection (EEP) technique.
Abstract
Purpose
A general strategy is developed for adaptive finite element (FE) analysis of free vibration of elastic membranes based on the element energy projection (EEP) technique.
Design/methodology/approach
By linearizing the free vibration problem of elastic membranes into a series of linear equivalent problems, reliable a posteriori point-wise error estimator is constructed via EEP super-convergent technique. Hierarchical local mesh refinement is incorporated to better deal with tough problems.
Findings
Several classical examples were analyzed, confirming the effectiveness of the EEP-based error estimation and overall adaptive procedure equipped with a local mesh refinement scheme. The computational results show that the adaptively-generated meshes reasonably catch the difficulties inherent in the problems and the procedure yields both eigenvalues with required accuracy and mode functions satisfying user-preset error tolerance in maximum norm.
Originality/value
By reasonable linearization, the linear-problem-based EEP technique is successfully transferred to two-dimensional eigenproblems with local mesh refinement incorporated to effectively and flexibly deal with singularity problems. The corresponding adaptive strategy can produce both eigenvalues with required accuracy and mode functions satisfying user-preset error tolerance in maximum norm and thus can be expected to apply to other types of eigenproblems.
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Terence Y.M. Lam and Junjie Yan
Shanghai is currently faced with a rapid increase in the ageing population and demand for elderly homes. Continuing care retirement community (CCRC) has been emerging as a…
Abstract
Purpose
Shanghai is currently faced with a rapid increase in the ageing population and demand for elderly homes. Continuing care retirement community (CCRC) has been emerging as a high-end alternative to offer specialised accommodation to the elderly in major cities. Since the first development in 2008, the industry is now still at the infancy stage. This study aims to examine the investment barriers hindering the supply and demand of CCRCs with an aim to recommend practical and senior housing policy measures to facilitate CCRC developments.
Design/methodology/approach
Multiple-case study method was used to confirm whether the literature findings on investment barriers apply to the context of Shanghai. Four representative CCRC development cases in Shanghai were examined, in which qualitative data were collected from interviews with experienced CCRC development managers and quantitative data from a questionnaire survey of the CCRC residents.
Findings
Operation management experience, financial risks and government support policy were found to be the main supply barriers. Chinese traditional family-oriented culture and affordability were not the main demand barriers of CCRCs in Shanghai. Poor quality of services and living environment were identified as the main barriers suppressing the demand for CCRC.
Research limitations/implications
Although common trends and views can be drawn from the representative cases in Shanghai to provide valid results, further research should be conducted on other major cities in China so that the results can be widely applied.
Practical implications
Successful CCRC investment strategy should focus on partnering with experienced professional eldercare management companies, provisions of high-quality medical professionals and trained care personnel and delivery of flexible care service, along with intensive capital flows for land, construction and operating costs.
Social implications
Additional senior housing policy support should be established to promote the CCRC supply to address the ageing needs, particularly granting lands for CCRC developments at Tiers 1 and 2 major cities where the land cost is high.
Originality/value
This research’s practical and policy measures can be applied to enable and promote CCRC developments in Shanghai, thus benefitting both housing investors and the government. The findings also form a baseline for CCRC developments in other major cities.
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Wei Yuan, Guangneng Dong, Kwai Sang Chin, Meng Hua and Qianjian Guo
Streak defect and dynamic harmonic excitation (DHE) loading play important roles in machine operating conditions. The purpose of this paper was to assess the effects of streak…
Abstract
Purpose
Streak defect and dynamic harmonic excitation (DHE) loading play important roles in machine operating conditions. The purpose of this paper was to assess the effects of streak defect and DHE loading on the tribological properties of surface-contact friction pairs, for example the differential gear end-face on the washer, via experimental investigation.
Design/methodology/approach
Streak defect was artificially introduced into the washer surface, which was loaded with DHE loads produced by a spring-connecting weight system. The wear scar of the washers and the monitored friction force signals were respectively scanned using scanning electron microscope (SEM) and analyzed using wavelet simulation.
Findings
The friction force curves, SEM images and discrete wavelet transform results indicate that DHE loading tends to increase friction force, to accelerate plowing damages and result in side-flow of material and plastic deformation on the surfaces of the washer. Whereas, streak oil-channel textures on washer specimen can be machined to modify the lubrication condition in the running-in stage so as to improve the tribological properties of the sliding pairs which were even subjected to DHE loading.
Originality/value
On the basis of this thesis research, the effect of streak defect and DHE loading on tribological performance of surface-contact sliding pairs is discussed. The results of wear form and friction state with the effect of streak defect and DHE loading facilitate to optimize the operating condition of mechanical parts.
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Abstract
Purpose
This study aims to explore the spatio-temporal dynamic characteristics and influencing factors of the coordination degree of the three systems of digital economy, energy and human habitat in Western China and to provide academic research support for promoting coordinated and sustainable development in similar regions of the world.
Design/methodology/approach
Based on system theory and sustainable development theory, this study primarily uses the coupled coordination degree model to assess the degree of coordination between the three systems.
Findings
The findings of this study indicate that: The three systems’ overall coordination is low. The distribution of the degree of coordination has spatial differences and its coefficient of variation is small. The probability of the coordination type changing for the better is greater than that of the opposite, and neighboring provinces interact with one another. The old-age dependence ratio, the resident population’s urbanization rate and public budget expenditure have the strongest gray association with the degree of coordination.
Practical implications
This study’s findings will be valuable for policymakers in developing policies to promote the coordinated and sustainable growth of the region’s digital economy, energy and human habitat. Additionally, the findings will aid in facilitating regional exchanges and cooperation to enhance the level of sustainable development.
Social implications
This study’s findings will contribute to increased social interest in coordinating sustainable growth in the digital economy, energy and human habitat.
Originality/value
This study examines the digital economy, energy and human habitat within the same framework and investigates spatial spillover effects using spatial Markov chains.