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Abstract

Graphical abstarct

Purpose

This paper aims to improve the refractive index sensor performance for analytes with large refractive index by adopting the technology of microstructured fiber (MF) and surface plasmon resonance (SPR).

Design/methodology/approach

The structure adopts an MF with a hexagonal lattice cladding structure composed of all-circular air holes, and three defect regions are introduced. The liquid analyte that needs to be tested is filled in the defect area. The surface plasmon polarition mode is generated and coupled with the core mode, thus forming a refractive index sensing channel. When the resonance conditions are satisfied, the resonance wavelength will be changed with the refractive index of the liquid analyte. All parameters that may affect the performance of the sensor are numerical simulated, and the structure is optimized through a large number of calculations.

Findings

The results demonstrate that the maximum dynamic sensitivity (SR) can reach to 24,260 nm/RIU, and the average sensitivity (SR-AV) can reach to 18,046 nm/RIU when the refractive index range is from 1.42 to 1.47. Besides, the sensitivity linearity (R2) is approximately 0.965, and its resolution is 4.1 × 10–6 RIU. The comparison with some literature results shown that the proposed sensor has certain advantages over the sensors reported in these literatures.

Originality/value

This work proposed an SPR-based refractive index sensor with a simple MF structure. It has a certain reference significance for the design and optimization of SPR-based MF sensors. Moreover, owing to its simple structure, high refractive index sensitivity and linear sensing performance, this sensor will play an important role in the detection of high refractive index liquid analytes.

Details

Sensor Review, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 0260-2288

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Article
Publication date: 24 January 2025

Rui Zhang, Qiang Zhang, Junbo Cheng and Xiaodong Zhou

Achieving accurate trajectory tracking control of robot manipulators is challenging due to dynamic model errors and uncertain payloads. This paper aims to enhance trajectory…

11

Abstract

Purpose

Achieving accurate trajectory tracking control of robot manipulators is challenging due to dynamic model errors and uncertain payloads. This paper aims to enhance trajectory tracking performance for robots with n degrees of freedom (DOF).

Design/methodology/approach

This study proposes a robust motion control framework that combines uncertainty and disturbance estimator with model-based compensation. The proposed framework ensures precise trajectory tracking in robot manipulators. In addition, uncertainties in the high-DOF robot dynamics are estimated through a simple model-based compensation for system error dynamics. The stability of the closed-loop system of the proposed framework is analyzed and proved.

Findings

The results indicate that the proposed framework can significantly reduce tracking errors and increase disturbance resistance. The simulation results of a two-link robotic arm verify the effectiveness of the proposed method. The results of the experiments conducted on a seven-DOF torque-controlled Flexiv4S manipulator demonstrate the superior trajectory tracking performance and robustness of the proposed algorithm.

Originality/value

This study introduces a highly efficient, robust motion control framework for high-DOF robots, which can improve the trajectory tracking performance in the presence of model uncertainties.

Details

Industrial Robot: the international journal of robotics research and application, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 0143-991X

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Article
Publication date: 19 October 2020

Nailong Liu, Xiaodong Zhou, Zhaoming Liu, Hongwei Wang and Long Cui

This paper aims to enable the robot to obtain human-like compliant manipulation skills for the peg-in-hole (PiH) assembly task by learning from demonstration.

481

Abstract

Purpose

This paper aims to enable the robot to obtain human-like compliant manipulation skills for the peg-in-hole (PiH) assembly task by learning from demonstration.

Design/methodology/approach

A modified dynamic movement primitives (DMPs) model with a novel hybrid force/position feedback in Cartesian space for the robotic PiH problem is proposed by learning from demonstration. To ensure a compliant interaction during the PiH insertion process, a Cartesian impedance control approach is used to track the trajectory generated by the modified DMPs.

Findings

The modified DMPs allow the robot to imitate the trajectory of demonstration efficiently and to generate a smoother trajectory. By taking advantage of force feedback, the robot shows compliant behavior and could adjust its pose actively to avoid a jam. This feedback mechanism significantly improves the dynamic performance of the interactive process. Both the simulation and the PiH experimental results show the feasibility and effectiveness of the proposed model.

Originality/value

The trajectory and the compliant manipulation skill of the human operator can be learned simultaneously by the new model. This method adopted a modified DMPs model in Cartesian space to generate a trajectory with a lower speed at the beginning of the motion, which can reduce the magnitude of the contact force.

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Article
Publication date: 1 August 2016

Yanqiu Chen, Xiaodong Zhou, Taolin Zhang, Zhijian Fu, Yuqi Hu and Lizhong Yang

– The purpose of this paper is to study the behavior of smoke flow in building fires and optimize the design of smoke control systems.

332

Abstract

Purpose

The purpose of this paper is to study the behavior of smoke flow in building fires and optimize the design of smoke control systems.

Design/methodology/approach

A total of 435 3-D fire simulations were conducted through NIST fire dynamics simulator to analyze thermal behavior of combined buoyancy-induced and pressure-driven smoke flow in complex vertical shafts, under consideration of influence of heat release rate (HRR) and locations of heat sources. This influence was evaluated through neutral pressure plane (NPP), which is a critical plane depicting the flow velocity distributions. Hot smoke flows out of shafts beyond the NPP and cold air flows into shafts below the NPP.

Findings

Numerical simulation results show that HRR of heat source has little influence on NPP, while location of heat source can make a significant difference to NPP, particularly in cases of multi-heat source. Identifying the location of NPP helps to develop a more effective way to control the smoke with less energy consumption. Through putting an emphasis on smoke exhausting beyond the NPP and air supplying below the NPP, the smoke control systems can make the best use of energy.

Research limitations/implications

Because of the chosen research approach, the research results may need to be tested by further experiments.

Practical implications

The paper includes implications for the optimization of smoke control systems design in buildings.

Originality/value

This paper fulfills an identified need to research the behavior of hot smoke in building fires and optimize the design of smoke control systems.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 26 no. 6
Type: Research Article
ISSN: 0961-5539

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Article
Publication date: 2 May 2008

Xiaodong Zhou, Huaqiang Shi, Xun Fu, Danmei Wu and Zhengshui Hu

The purpose of this paper is to investigate the tribological properties of MoS2 nano‐sized hollow spheres in liquid paraffin (LP) and the corresponding action mechanism. Morever…

745

Abstract

Purpose

The purpose of this paper is to investigate the tribological properties of MoS2 nano‐sized hollow spheres in liquid paraffin (LP) and the corresponding action mechanism. Morever, its feasibity of industrial application as an oil additive in the industrial lubrication field is also explored.

Design/methodology/approach

The tribological properties of MoS2 nano‐sized hollow spheres (NH‐MoS2) modified by Cyanex 301(di‐(2,4,4‐trimethylpentyl) dithiophosphinic acid) with size of 200 ∼ 300 nm in LP are studied and compared with those of the commercial colloidal MoS2 (CC‐MoS2) on a four‐ball tester and an Optimol SRV Oscillating friction and wear tester in a ball‐on disk configuration. The worn surfaces of the lower flat disc are examined with a scanning electron microscopy and an X‐ray photoelectron spectroscopy, respectively.

Findings

Results show that NH‐MoS2 is a better extreme‐pressure additive and anti‐wear (AW) and friction‐reducing additive in LP than CC‐MoS2. Under the optimum concentration of 0.5 per cent for both NH‐MoS2 and CC‐MoS2 and the load of 400 N, the friction coefficient of NH‐MoS2 + LP and CC‐MoS2 + LP decreases about 43.8 and 6.3 per cent, and the wear volume loss decreases about 60.3 and 12.0 per cent compared with the pure LP. The boundary lubrication mechanism for NH‐MoS2 + LP can be deduced as the effective chemical adsorption protective film formed by the long chain alkyls R and active elements (S and P) in the modification layer and tribochemical reaction film containing the tribochemical products of the additive. Moreover, sliding and rolling frictions co‐exist in NH‐MoS2 + LP, doing contributions to the good tribological properties as well.

Originality/value

In this paper, the Cyanex 301‐modified MoS2 nano‐sized hollow spheres with diameter of 200 ∼ 300 nm are firstly added into LP to investigate its tribological properties. The excellent AW and friction‐reducing properties indicate that this MoS2 hollow spheres product is a good oil additive, and the fundamental data presented here will be useful for its further industrial application in the future.

Details

Industrial Lubrication and Tribology, vol. 60 no. 3
Type: Research Article
ISSN: 0036-8792

Keywords

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Article
Publication date: 7 April 2015

Yanqiu Chen, Xiaodong Zhou, Taolin Zhang, Yuqi Hu and Lizhong Yang

– The purpose of this paper is to study the behavior of smoke flow in a typical high-rise residential building fire in six common smoke control systems.

528

Abstract

Purpose

The purpose of this paper is to study the behavior of smoke flow in a typical high-rise residential building fire in six common smoke control systems.

Design/methodology/approach

The pressure, temperature and CO2 concentration were used to trace the motion of turbulent smoke flow through CFD.

Findings

It is found that the hot smoke could rise up and spread into the indoor space on the upper floors through the staircase. When the pressure in the evacuation staircase is higher, it would be more difficult for the smoke to enter the staircase and transport vertically. On the other hand, the smoke would soon transport to the indoor space on the upper floors horizontally. During this process, the smoke shows a more disorder horizontal transport under the sole effect of thermal buoyancy than the co-existence of thermal buoyancy and the air inlet.

Research limitations/implications

Because of the chosen research approach, the research results may need to be tested by further experiments.

Practical implications

The paper includes implications for the design of smoke control systems and evacuation in a building fire.

Originality/value

This paper fulfils an identified need to study the behavior of smoke in a fire and optimize the design of smoke control systems.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 25 no. 3
Type: Research Article
ISSN: 0961-5539

Keywords

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Article
Publication date: 27 August 2019

Shengliang Zhang, Yuan Chen, Xiaodong Li and Guowei Dou

The purpose of this study is to use role expectation theory to identify potential determinants of user voting avoidance on mobile social media.

257

Abstract

Purpose

The purpose of this study is to use role expectation theory to identify potential determinants of user voting avoidance on mobile social media.

Design/methodology/approach

Data were collected through a survey of 602 WeChat users, and the proposed model was analysed using structural equation modelling.

Findings

Results indicate that user voting avoidance was positively influenced by unfair competition, perceived inauthenticity, perceived information insecurity, over-consumption of renqing (a unique Chinese human relation) and organisation placement in the context of mobile social media.

Originality/value

This study illustrates mobile user voting avoidance from the perspective of role expectation theory and clarifies the importance of avoidance in current voting research.

Details

Kybernetes, vol. 49 no. 5
Type: Research Article
ISSN: 0368-492X

Keywords

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Article
Publication date: 8 August 2022

Liying Zhou, Fei Jin, Banggang Wu, Xiaodong Wang, Valerie Lynette Wang and Zhi Chen

This study aims to examine if the participation of live-stream influencers (LSIs) affects tipping frequency on live streaming platforms, and further investigate the mediating and…

3533

Abstract

Purpose

This study aims to examine if the participation of live-stream influencers (LSIs) affects tipping frequency on live streaming platforms, and further investigate the mediating and moderating mechanisms.

Design/methodology/approach

Quasi-experiment and difference-in-differences models are used for data analysis. Propensity score matching is used to address potential unobservable endogeneity.

Findings

Real-time live streaming data reveal that LSIs’ participation significantly improves tipping frequency in live streaming rooms. Also, more users are attracted to the live streaming rooms and more users become active in participation. Additionally, the positive impact of LSIs’ participation is enhanced in the live streaming rooms with a greater number of relationship links between users.

Research limitations/implications

The findings clarify the new role of influencers and reveal the mechanisms on how LSIs benefit the platforms.

Practical implications

The findings offer novel insights into implementing influencer marketing to interactive social media platforms, by encouraging influencer participation, user relationship building and influencer network growth.

Originality/value

This study highlights the value of LSIs for interactive social media platforms in terms of organic growth, revenue generation and cost reduction.

Details

European Journal of Marketing, vol. 56 no. 10
Type: Research Article
ISSN: 0309-0566

Keywords

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Article
Publication date: 4 December 2017

Longwei Wang, Min Zhang and Xiaodong Li

The purpose of this paper is to empirically investigate the effects of competence and goodwill trust on knowledge creation and the moderating effects of legal inadequacy on those…

507

Abstract

Purpose

The purpose of this paper is to empirically investigate the effects of competence and goodwill trust on knowledge creation and the moderating effects of legal inadequacy on those relationships.

Design/methodology/approach

A questionnaire survey was used to collect data from 196 research and development alliances in China. Hierarchical moderated regression was used to test the research hypotheses.

Findings

The authors find that competence trust has a positive and linear relationship with knowledge creation while goodwill trust has an inverted U-shaped relationship with it. The results also reveal that the inverted U-shaped relationship between goodwill trust and knowledge creation is stronger when legal inadequacy is high, while the impact of competence trust on knowledge creation is not influenced by legal inadequacy.

Originality/value

The findings provide insights into the distinctive effects of competence and goodwill trust on knowledge creation in partnerships, deepening current understandings of the bright and dark sides of inter-firm trust. This study also clarifies the influences of legal inadequacy on the effectiveness of competence and goodwill trust, which enhances existing knowledge about the impact of legal systems on the relationships between inter-firm trust and knowledge management.

Details

Industrial Management & Data Systems, vol. 117 no. 10
Type: Research Article
ISSN: 0263-5577

Keywords

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Article
Publication date: 22 March 2019

Longwei Wang, Xiaodong Li and Min Zhang

The purpose of this paper is to empirically investigate the effects of cooperation history on contractual governance and the moderating effects of dependence asymmetry on those…

277

Abstract

Purpose

The purpose of this paper is to empirically investigate the effects of cooperation history on contractual governance and the moderating effects of dependence asymmetry on those relationships from the perspective of a weaker firm in emergent economies. Drawing from resource dependence theory and contingency theory, this paper develops a conceptual model to investigate the impact of cooperation history on contractual governance.

Design/methodology/approach

The authors use data from 188 buyer–supplier relationships in China

Findings

The authors find that cooperation history is positively associated with contractual governance when dependence asymmetry is high but negatively associated with contractual governance when dependence asymmetry is low. Furthermore, the negative moderating effect of dependence asymmetry on the relationship between cooperation history and contractual complexity is stronger than the relationship between cooperation history and contract enforcement.

Originality/value

This study contributes to a better understanding of how cooperation history affects contractual governance with respect to the various levels of dependence on partners by incorporating a contingency view. This study also advances the literature on interfirm governance by distinguishing contractual governance into contractual complexity and contract enforcement.

Details

Baltic Journal of Management, vol. 14 no. 3
Type: Research Article
ISSN: 1746-5265

Keywords

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