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Article
Publication date: 23 June 2020

Guohua Zhang, Gongnan Xie and Bengt Ake Sunden

In this study, numerical simulations are performed to compare the adiabatic film cooling effectiveness and reveal the difference of film cooling mechanisms of two models…

Abstract

Purpose

In this study, numerical simulations are performed to compare the adiabatic film cooling effectiveness and reveal the difference of film cooling mechanisms of two models with the same geometries and cross-section areas of film holes’ exits at three typical blowing ratios (M = 0.5, 1 and 1.5). The two models are an elliptical model and a cylindrical model with 90° compound angle, respectively.

Design/methodology/approach

Three different cases are considered in this work and the baseline is the model with a cylindrical film hole. The same boundary conditions and a validated turbulence model (realizable k-ε) are adopted for all cases.

Findings

The results show that both the elliptical and cylindrical models with 90° compound angle can enhance the film cooling effectiveness compared with the baseline. However, the elliptical model performs well at lower blowing ratios and in the near region at each blowing ratio because of the wider width of the film hole’s exit. The cylindrical model with 90° compound angle provides better film cooling effectiveness in the further downstream area of the film hole at higher blowing ratio because of the less lift-off and better coolant coverage in the larger x/D region along the mainstream direction.

Originality/value

Overall, it can be concluded that although the elliptical and cylindrical models with 90° compound angle have identical hole exits, the different inlet direction and cross-sectional geometry affect the flow structures when the coolant enters, moves through and exits the hole and finally different film cooling results appear.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 31 no. 1
Type: Research Article
ISSN: 0961-5539

Keywords

Article
Publication date: 3 May 2016

Di Ma, Shubai Li, Longgui Xu, Xiuying Hu, Guohua Zhang, Chuanqi Jia and Xinchao Yuan

This paper aims to study the anodization of aluminum in a mixture solution of 1,3-propanediol solutions and 0.4 mol l−1 H3PO4 at a low temperature.

Abstract

Purpose

This paper aims to study the anodization of aluminum in a mixture solution of 1,3-propanediol solutions and 0.4 mol l−1 H3PO4 at a low temperature.

Design/methodology/approach

The morphology and composition of the resulting anodic aluminum oxide (AAO) template was characterized by means of a scanning electron microscope in combination with an energy dispersive spectrometer.

Findings

Pore density and pore diameter both were found to be dependent on the temperature of anodization.

Originality/value

The resulting AAO templates exhibited uniform and regular pores with diameters that were significantly smaller than those found in AAO templates anodized at room temperature.

Details

Anti-Corrosion Methods and Materials, vol. 63 no. 3
Type: Research Article
ISSN: 0003-5599

Keywords

Article
Publication date: 31 July 2019

Guohua Zhang, Xueting Liu, Bengt Ake Sundén and Gongnan Xie

This study aims to clarify the mechanism of film hole location at the span-wise direction of an internal cooling channel with crescent ribs on the adiabatic film cooling…

Abstract

Purpose

This study aims to clarify the mechanism of film hole location at the span-wise direction of an internal cooling channel with crescent ribs on the adiabatic film cooling performance, three configurations are designed to observe the effects of the distance between the center of the ellipse and the side wall(Case 1, l = w/2, Case 2, l = w/3 and for Case 3, l = w/4).

Design/methodology/approach

Numerical simulations are conducted under two blowing ratios (i.e. 0.5 and 1) and a fixed cross-flow Reynolds number (Rec = 100,000) with a verified turbulence model.

Findings

It is shown that at low blowing ratio, reducing the distance increases the film cooling effectiveness but keeps the trend of the effectiveness unchanged, while at high blowing ratio, the characteristic is a little bit different in the range of 0 = x/D =10.

Research limitations/implications

These features could be explained by the fact that shrinking the distance between the hole and side wall induces a much smaller reserved region and vortex downstream the ribs and a lower resistance for cooling air entering the film hole. Furthermore, the spiral flow inside the hole is impaired.

Originality/value

As a result, the kidney-shaped vortices originating from the jet flow are weakened, and the target surface can be well covered, resulting in an enhancement of the adiabatic film cooling performance.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 29 no. 8
Type: Research Article
ISSN: 0961-5539

Keywords

Article
Publication date: 15 June 2015

Chuanqi Liu, Qicheng Sun and Guohua Zhang

Granular materials possess multiscale structures, i.e. micro-scales involving atoms and molecules in a solid particle, meso-scales involving individual particles and their…

Abstract

Purpose

Granular materials possess multiscale structures, i.e. micro-scales involving atoms and molecules in a solid particle, meso-scales involving individual particles and their correlated structure, and macroscopic assembly. Strong and abundant dissipations are exhibited due to mesoscopic unsteady motion of individual grains, and evolution of underlying structures (e.g. force chains, vortex, etc.), which defines the key differences between granular materials and ordinary objects. The purpose of this paper is to introduce the major studies have been conducted in recent two decades.

Design/methodology/approach

The main properties at individual scale are introduced, including the coordination number, pair-correlation function, force and mean stress distribution functions, and the dynamic correlation function. The relationship between meso- and macro-scales is analyzed, such as between contact force and stress, the elastic modulus, and bulk friction in granular flows. At macroscales, conventional engineering models (i.e. elasto-plastic and hypo-plastic ones) are introduced. In particular, the so-called granular hydrodynamics theory, derived from thermodynamics principles, is explained.

Findings

On the basis of recent study the authors conducted, the multiscales (both spatial and temporal) in granular materials are first explained, and a multiscale framework is presented for the mechanics of granular materials.

Originality/value

It would provide a paramount view on the multiscale studies of granular materials.

Details

Engineering Computations, vol. 32 no. 4
Type: Research Article
ISSN: 0264-4401

Keywords

Article
Publication date: 5 February 2021

Ying Zhang, Xing Lu and Wikrom Prombutr

The authors investigate the extent to which online talk can influence contemporaneous and future stock trading, especially when market news is unpresented.

Abstract

Purpose

The authors investigate the extent to which online talk can influence contemporaneous and future stock trading, especially when market news is unpresented.

Design/methodology/approach

The authors propose an improved sentiment formula incorporating online hype, neutral sentiment and poster reputation. In addition, they conduct event study, OLS regression analyses and probit models.

Findings

First, investors tend to be more talkative in relation to firms that are (1) smaller size, (2) more growth-like, (3) with lower prices and higher short interests and (4) of higher beta. Second, the bullish tone of investors positively affects the abnormal returns of small-capitalization stocks. However, online talk has little impact on large-capitalization stocks, except that more postings boost trading liquidity. Third, online talk predicts the presence of future news regardless of firm size, with stronger predictive power found for small-capitalization stocks.

Practical implications

It is of interest to practitioners and researchers to study online talk so as to better understand the trading psychology of retail investors and the effects on the stock market. Furthermore, policymakers are interested in tracking activities on stock message boards in order to prevent security fraud and protect investors' interests.

Originality/value

The results are robust and suggest that online talk has significant impacts on stock trading exploiting an information asymmetry. This study of stock message board posting activities helps researchers to understand whether message contents contain valuable and unique content compared with information available via more traditional media channels.

Details

Review of Behavioral Finance, vol. 14 no. 2
Type: Research Article
ISSN: 1940-5979

Keywords

Article
Publication date: 7 April 2021

Guohua Cao and Jing Zhang

This study aims to combine two fraud-related streams of the literature on guanxi and overconfidence into an integrated framework, which is the fraud triangle, to interpret…

Abstract

Purpose

This study aims to combine two fraud-related streams of the literature on guanxi and overconfidence into an integrated framework, which is the fraud triangle, to interpret the mechanism of fraud commission and detection.

Design/methodology/approach

A bivariate probit model with Partial Observability (POBi Probit) is applied. Moreover, the POBi Probit model is adjusted to the Chinese context. The China-specific POBi Probit model is constructed using data of Chinese A-share listed companies from 2008 to 2014, with a total of 15,109 firm-year observations.

Findings

Overconfidence induces fraud commission and worsens fraud detection; overconfidence mediates the relationship between fraud and guanxi; the “white side” of guanxi comes from alumni networks, while the “dark side” is derived from relatives-based networks; overconfidence induces fraud commission in accounting and disclosure and benefits the detection of disclosure frauds. Guanxi suppresses fraud commission in management and disclosure, however, it worsens fraud detection given fraud in management and disclosure; overconfidence induces fraud commission in both state-owned enterprises (SOE) and non-SOEs, and benefits fraud detection in SOEs. Guanxi suppresses fraud commission and worsens fraud detection in SOEs and city-owned firms.

Research limitations/implications

There are two drawbacks of the partial observable bivariate probit (POBi-Probit) method that must be mentioned here. On one hand, the ex ante variable selection is one of the most difficult parts of applying the POBi-Probit model and different variables are included in different studies. On the other hand, the POBi-Probit model might not converge if too many variables are included. Thus, many widely accepted factors can be included in the model. Thus, this study initially sets the POBi-Probit model based mainly on Khanna et al. (2015) and then adjusts the model for the Chinese context (e. g. considering government ownership) according to Yiu et al. (2018) and Zhang (2018) and the local study of Meng et al. (2019). Considering the observability of fraud, on one hand, the observability of fraud commission is a widely accepted limitation, especially when accounting opacity comes across with regulatory efficiency (Yiu et al. (2018). On the other hand, the observability of relationships is another obstacle to this study. Future studies can go further by revealing the presently unobservable relationships using Big Data technology.

Originality/value

This paper theoretically and practically contributes to the literature on both corporate fraud and corporate governance. Theoretically, by introducing integrated principal-agent resource-reliance theory (IPRT) and upper echelon theory (UET), this paper broadens the framework of fraud triangle theory (FTT) and testifies the availability of the broaden FTT in the transitional and emerging-market context of China. Practically, this paper provides evidence that guanxi and overconfidence are two of the factors affecting corporate fraud. Thus, this paper provides a governance approach opposing corporate fraud in China, which may help the other emerging economies in transition.

Details

Chinese Management Studies, vol. 15 no. 3
Type: Research Article
ISSN: 1750-614X

Keywords

Article
Publication date: 10 December 2018

Feng Zhang and Guohua Jiang

Firms increasingly diversify their technological competencies to achieve different strategic objectives. This study aims to explore the impacts of technological knowledge…

Abstract

Purpose

Firms increasingly diversify their technological competencies to achieve different strategic objectives. This study aims to explore the impacts of technological knowledge characteristics on patenting choices for inventions created by subsidiaries in an uncertain and fast changing environment.

Design/methodology/approach

The data used in this study are patents granted to the world largest firms by the USPTO for inventions attributable to their subsidiaries in China between 1996 and 2005. In addition, the patent data from State Intellectual Property Office (SIPO) of China are used for the matching in terms of filing patent applications in both USA and China for a same piece of technology. A discrete Logit model is used to examine the effects of technological distance and categories on Chinese patent application and international priority.

Findings

The findings suggest that firms have priority to seek international patent protection, instead of host country protection, for valuable subsidiary inventions in their background and marginal technological fields. In addition, a firm may seek host country legal protection simultaneously for inventions built upon knowledge from technologically distant fields.

Research limitations/implications

As we are more interested in protecting technological knowledge, the protection of other types of knowledge, such as organizational knowledge, deserves further research attentions. Moreover, future research may expand current study by including small and medium firms, as well as firms in other developing economies.

Practical implications

While the economic and legal environment in China may have evolved since studied period, the results have practical implications for firms in other developing countries that are at an early stage of catching-up or those in a host location featuring a similar uncertain and fast changing environment. In particular, the study suggests that foreign firm managers would have more strategic choices of patenting than local firms in the host country. For strategically important inventions bridging complex knowledge from different technological areas, firms could seek protection in multiple countries simultaneously, including both home country and other major markets. Furthermore, managers could choose whether or not to protect a particular category of technologies in host country depending on value of the technology to the firm and the IPR protection of host country. Finally, the approach of looking at knowledge-level characteristics, which can be easily measured through readily available intra-firm information, provides managers with a practical and useful tool to make these strategic decisions.

Originality/value

This study represents an effort to extend the understanding on how foreign MNCs could generate and appropriate valuable technologies in an uncertain and fast-changing environment. In particular, the authors focus on how MNCs could use different international patenting patterns to benefit from subsidiary inventions. Whereas previous literature mainly focuses on country-level and firm-level determinants, this study approaches the topic through the lens of knowledge-level factors. By studying how knowledge characteristics determine firm strategic behaviors, the authors offer additional justifications of the knowledge-based view of the firm. Meanwhile, the findings enrich our understanding of an important component of MNC’s global strategies in managing their technologies through selectively patenting in different locations. Firms pursue diversified technologies for different strategic objectives. As subsidiary inventions become a very important source of firm competitiveness, MNCs have to face the trade-off between higher patenting costs and the appropriability of subsidiary generated knowledge. The findings suggest that it is not necessary for MNCs to protect all subsidiary inventions in host countries.

Details

Journal of Asia Business Studies, vol. 12 no. 4
Type: Research Article
ISSN: 1558-7894

Keywords

Article
Publication date: 4 June 2019

Guohua He, Ran An and Patricia Faison Hewlin

This paper aims to explore the psychological mechanism in the relationship between paternalistic leadership (PL) and employee well-being (EWB) in cross-cultural nonprofit…

Abstract

Purpose

This paper aims to explore the psychological mechanism in the relationship between paternalistic leadership (PL) and employee well-being (EWB) in cross-cultural nonprofit organizations. It also aims to further promote the integration of research on PL and self-concept by examining the relationship between PL and collective self-concept (CSC).

Design/methodology/approach

Data were collected on 72 supervisors and 233 expatriate Chinese teachers from 42 Confucius Institutes and 15 Confucius classrooms in Canada and the USA.

Findings

PL has a significant effect on EWB. Benevolent and moral leadership are positively related to CSC, while authoritarian leadership is negatively related to CSC. CSC mediates the relationship between PL and EWB. Furthermore, employees’ cross-cultural adaptability positively moderates the relationship between CSC and EWB; the indirect effect between PL and EWB via CSC is stronger for employees with stronger cross-cultural adaptability.

Originality/value

This is the first study that has examined the psychological mechanism under which PL affects EWB in cross-cultural nonprofit organizations. It contributes to the integration of research on PL and CSC by examining its relationship for the first time. It provides important implications for improving the well-being of expatriate employees in cross-cultural organizations.

Details

Chinese Management Studies, vol. 13 no. 3
Type: Research Article
ISSN: 1750-614X

Keywords

Article
Publication date: 2 January 2018

Guohua Jiang, Dongmei Zhao and Bo Zhao

The purpose of this paper is to investigate the optoelectronic properties of the multichannel ZnO UV photodetectors.

Abstract

Purpose

The purpose of this paper is to investigate the optoelectronic properties of the multichannel ZnO UV photodetectors.

Design/methodology/approach

ZnO nanowires were assembled by dielectrophoresis for the UV photodetectors. Different ZnO channels were adjusted by different alternating current voltages and investigated for UV optoelectronic properties.

Findings

The number of the ZnO channels increases with the enhancing alternating current voltage. Optimum performance of the UV photodetectors is obtained with more channels.

Originality/value

Dielectrophoresis is a promising method for controllable assembly of multichannel ZnO photodetectors. ZnO photodetectors with more channels demonstrate a good response to 380-nm UV light, which shows great potential application in UV photodetector.

Details

Microelectronics International, vol. 35 no. 1
Type: Research Article
ISSN: 1356-5362

Keywords

Article
Publication date: 20 July 2021

Guohua He, Yanfei Wang, Xinnian Zheng, Zisheng Guo and Yu Zhu

This study explores how paternalistic leadership (PL) influences Chinese expatriates' work engagement in a cross-cultural context, and examines how expatriates'…

Abstract

Purpose

This study explores how paternalistic leadership (PL) influences Chinese expatriates' work engagement in a cross-cultural context, and examines how expatriates' cross-cultural adaptability sets a boundary condition for this relationship.

Design/methodology/approach

Data were collected from two-wave surveys of 82 supervisors and 318 Chinese expatriate teachers from 57 Confucius Institutes in 18 countries. Structural equation modeling was used to test the hypothesized relationships.

Findings

Benevolent and moral leadership as job resources are negatively related to work–family conflict (WFC), whereas the job demand of authoritarian leadership positively relates to WFC. Further, WFC mediates the effect of PL styles on Chinese expatriates' work engagement. Cross-cultural adaptability moderates the negative relationship between WFC and work engagement, and the indirect effect of PL styles on work engagement through WFC.

Practical implications

Organizations should consider WFC an important intervening mechanism linking PL and Chinese expatriates' work engagement. Cross-cultural organizations can mitigate the negative impact of WFC on work engagement by enhancing expatriates' cross-cultural adaptability.

Originality/value

This study is the first to examine the PL–work engagement relationship via a work–family interface, which contributes to integrating leadership and work–family outcomes. It enriches research on the JD-R model by showing that job resources and job demands affect employee outcomes through the mediation of stressors. Furthermore, this study identifies a new personal resource by examining cross-cultural adaptability's moderating role.

Details

International Journal of Manpower, vol. 43 no. 4
Type: Research Article
ISSN: 0143-7720

Keywords

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