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The purpose of this paper is to verify the relationship between the features of social media and knowledge sharing, and to examine how ambient awareness mediates this relationship.

An experiment is designed to stimulate the knowledge work in a famous Chinese business college and 156 valid samples were obtained. AMOS was used in this paper to examine the theoretical model.

There is a correlation among features of social media, ambient awareness and knowledge sharing. Surprisingly, network translucence, which indicates individuals’ meta-knowledge of others’ connections, has no influence on knowledge sharing. Although this is inconsistent with conjecture of the existing literature, it can be well explained by the phenomenon in real life, such as privacy setting in social media.

For employees who use social media to promote knowledge sharing within organizations, this study reminds them of the importance of ambient awareness. For managers, this study can give them some suggestions to make employees take full advantage of social media to achieve optimal benefits of knowledge sharing, thus improving organizational performance and innovation. For social media designers, they can make social media more useful in knowledge work by improving its specific features.

This paper proposes that ambient awareness is the mediator of the effect path between communication and knowledge sharing. And the status perception of coworkers’ exchanging information is closely related to knowledge sharing.

Smart cities show a “booming” trend both in the academia and the industry in recent years. Scholars across the world have been investigating how new technologies are applied to develop new services to the inhabitants and cities all over the world also address the “smart cities” challenges by promoting policymaking and governance. This paper aims to conduct in-depth research on smart cities by combining the study of governance policy study and information technology study.

This paper empirically mapped the trends of smart city development, outstanding scholars and hot topics about smart cities by analyzing important references using CiteSpace. The authors visualized references and topics to analyze smart city research, based on empirical data from Web of Science. Furthermore, two most important research branches – topics from smart city governance research and those from information systems (IS) research were studied, respectively.

First, the authors mapped the development of research and divided the development into three different stages. Second, the authors explored important, influential and instructive publications and publications’ attributes including authors, institutions, journals and topics. Third, the authors found there are different characteristics between the IS group and the governance group in publication situations, influential institutions, journals and authors, although the research points of the two branches are overlapping and fragmented. Finally, the authors proposed important topics, which include “internet of things (IoT)”, “big data”, “smart city systems” and “smart city management” and the authors predicted that “IoT” and “smart city challenge” would be future trends in recent years.

This study is an innovative research of its category because it visualized the development of smart city research, analyzed both governance and technology branches of smart city research synthetically using CiteSpace and forecasted future trends of smart city research by topics analysis and visualization of evolution.

This paper aims to enable the unmanned aerial vehicles to inspect the surface condition of wind turbine in close range when the global positioning system signal is not reliable, and further improve its intelligence. So a visual-inertial odometry with point and line features is developed.

Visual front-end combining point and line features, as well as its purification strategies, are first presented to improve the robustness of feature tracking in low-textured scene and rapidity of segment detector. Additionally, the inertial measurement is integrated between keyframes as constrain to reduce tracking error existed in visual-only system. Second, the graph-based visual-inertial back-end is constructed. To parameterize line features effectively, the infinite line representation not sensitive to outdoor light is employed, in which Plücker and Cayley are selected for line re-projection and nonlinear optimization. Furthermore, Jacobians of the line re-projection errors are analytically derived for better accuracy.

Experiments are performed in various scenes of the wind farm. The results demonstrate that the tight-coupled visual-inertial odometry with point and line features is more precise on all the samples than conventional algorithms in complex wind farm environments. Additionally, the constructed line feature map can be used in the following research for autonomous navigation.

The proposed visual-inertial odometry works robustly in strong electromagnetic interference, low-textured and illumination-change wind farm.

The purpose of this study is to measure and analyze the national innovation efficiency of organisation for economic co-operation and development (OECD) countries. This is to determine to what extent OECD countries efficiently use the elements that enable innovation activities possible in generating innovation outputs.

An input–output model was constructed to measure efficiency. The inputs and outputs in the research model are the input and output sub-indices of the Global Innovation Index. Data envelopment analysis was used to measure the national innovation efficiency levels of OECD countries.

The results show that national innovation efficiency is generally high in OECD countries. However, some countries lag behind in innovation efficiency. OECD countries’ ability to create and provide the elements that enable innovation activities is higher than their ability to create innovation outputs. OECD countries have a good innovation environment and a high level of resources, but they should focus on how to create more innovation outputs.

This study presents a measurement of national innovation efficiency of OECD countries which contributes “Innovation Strategy” agenda. The results empirically show that overall innovation indices cannot be the only indicator of the performance of national innovation systems. In this study, an innovation efficiency/performance matrix is constructed to present the relative positions of the countries to help in examining countries’ strengths, weaknesses and potentials based on innovation efficiency and innovation performance simultaneously. This study contributes to the literature by presenting a broader perspective and measurement of national innovation efficiency by taking an extensive number of indicators into account.

The purpose of this paper is to expound the relationship among microstructure, mechanical property, tribological behavior and deformation mechanism of carburized layer deposited on Ti-6Al-4V alloy by double-glow plasma hydrogen-free carburizing surface technology.

Morphologies and phase compositions of the carburized layer were observed by scanning electron microscope and X-ray diffraction. The micro-hardness tests were used to evaluate the surface and cross-sectional hardness of carburized layer. The reciprocating friction and wear experiments under various load conditions were implemented to investigate the tribological behavior of carburized layer. Moreover, scratch test with ramped loading pattern was carried out to illuminate the deformation mechanism of carburized layer.

Compared to substrate, the hardness of surface improved to ∼1,100 HV_0.1, while the hardness profile of carburized layer presented gradual decrease from ∼1,100 to ∼300 HV_0.1 within the distance of the total carburizing-affected region about 30 µm. The coefficient of friction, wear rate and wear morphology of carburized layer were analyzed. Scratch test indicated that the deformation process of carburized layer could be classified into three mechanisms (elastic, changing elastic–plastic and stable elastic–plastic mechanisms), and the deformation transition of the carburizing-affected region was from changing elastic–plastic to elastic mechanisms. Both the elastic and changing elastic–plastic mechanisms are conducive to the wearing course.

Using this technology, hydrogen embrittlement was avoided and wear resistance property of titanium alloy was greatly improved. Simultaneously, the constitutive relation during the whole loading process was deduced in terms of scratch approach, and the deformation mechanism of carburized layer was discussed from a novel viewpoint.

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-11-2019-0489/

Abundant oil and gas reservoirs in the deep-water are the valuable non-renewable energy sources. However, sea-water could enhance the corrosion of marine equipment such as submarine pipe trees. Various coatings, for example, polyurethane (PU) coatings are sprayed on the steel surfaces to enhance the anti-corrosion performance. Thus, to improve the anti-corrosion behavior of PU coatings in sea-water is imperative.

In this paper, the corrosion behaviors of 4130 carbon steel with and without PU coatings were discussed by electrochemical mean in sea-water. And the graphene additive in different concentrations (0.1, 0.3, 0.6 and 0.9 per cent) were also studied. A series of characterized methods were introduced to identify the anti-corrosion performances of 4130 carbon steel with and without coatings, respectively.

The results showed that the anti-corrosion property of 4130 carbon steel can enhance obviously with the PU coatings. The graphene additive can further improve the anti-corrosion behaviour of PU coatings and in the concentration of 0.6 per cent the PU/graphene coatings worked best.

This is beneficial for enhancing the service life of marine equipment in an eco-friendly method.

The purpose of this paper is to study the mechanism and effect of rare earth oxides on the properties of Cr₂O₃-TiO₂ coating.

Cr₂O₃-TiO₂ coatings with different proportion of CeO₂ were deposited by atmospheric plasma spraying on aluminum alloy 7005. The mechanical, microstructure and tribological properties were studied.

The addition of CeO₂ could improve the micro-hardness; decrease porosity, wear rate and surface roughness of the coating; and increase the bonding strength between the coating and substrate. The wear mechanism is a mixture of abrasive and adhesive wear.

The addition of CeO₂ could refine microstructure, and promote the formation of solid solution structure, and then affect the properties of coatings.

The purpose of this paper is to investigate the friction and wear mechanisms in copper-based self-lubricating composites with MoS₂ as the lubricating phase, which provides a theoretical basis for subsequent research on high-performance copper-based self-lubricating materials.

Friction tests were performed at a speed of 100 r/min, a load of 10 N, a friction radius of 5 mm and a sliding speed of 30 min. Friction experiments were carried out at RT-500°C. The phase composition of the samples was characterized by X-ray diffraction of Cu Ka radiation, and the microstructure, morphology and elemental distribution were characterized by scanning electron microscopy and energy dispersive spectroscopy. Reactants and valences formed during the wear process were analyzed by X-ray photoelectron spectroscopy.

The addition of MoS₂ can effectively improve friction-reducing and anti-wear action of the matrix, which is beneficial to form a lubricating film on the sliding track. After analyzing different changing mechanism of the sliding tracks, the oxides and sulfides of MoS₂, MoO₂, Cu₂O, CuO and Ni(OH)₂ were detected to form a synergetic lubricating film on the sliding track, which is responsible for the excellent tribological properties from room to elevated temperature.

For self-lubrication Cu–Sn–Ni–MoS₂ material in engineering field, there are still few available references on high-temperature application.

This paper provides a theoretical basis for the following research on copper-based self-lubricating materials with high performance.

With this statement, the authors hereby certify that the manuscript is the results of their own effort and ability. They have indicated all quotes, citations and references. Furthermore, the authors have not submitted any essay, paper or thesis with similar content elsewhere. No conflict of interest exits in the submission of this manuscript.

This study systematically investigated the effect of the binary rare earth oxide of La₂O₃ and Sm₂O₃ on the properties of the Al₂O₃/TiO₂ (AT) coating, including phase transform, wear behavior, etc.

AT coatings mixed with different components of binary rare earth oxides of La₂O₃ and Sm₂O₃ are prepared by atmospheric plasma spraying. The adhesion strength, micro-hardness, phase transition and tribological behavior of coatings are systematically investigated.

The X-ray diffraction (XRD) analysis shows that phase transformation is obvious after spraying, and a-Al₂O₃ is almost translated into γ-Al₂O₃ when La₂O₃ and Sm₂O₃ are doped together. Meanwhile, solid solution generated between rare earth oxide and Al₂O₃/TiO₂ coatings results in disappearance of TiO2 and rare earth oxide phase. The photos under the scanning electron microscope (SEM) indicate that binary rare earth oxide could increase the melting degree of powder and decrease porosity of coatings.The increasing of Sm₂O₃ rarely affect micro-hardness and adhesion strength, and the coating with 4 per cent Sm₂O₃ and 1 per cent La₂O₃ exhibits the best wear resistance and lowest friction coefficient among all the samples.

AT coatings mixed with different components of binary rare earth oxide of La₂O₃ and Sm₂O₃ are prepared by atmospheric plasma spraying. Binary rare earth oxide could increase the melting degree of powder and decrease porosity of AT coatings.

Tantalum is a kind of metal material with moderate hardness, high ductility, small thermal expansion coefficient, excellent corrosion resistance and outstanding biocompatibility. The purpose of this study is that its tribological performance could be tested and analyzed so as to use it in different fields.

The friction resistance of a-Ta under dry friction conditions was tested at different roads. The relationships between load and friction coefficient, wear rate and two-dimensional shape of wear scars were studied.

The stable Ta₂O₅ film with lubrication effect was generated in the process of friction. And, the larger the test load, the more Ta₂O₅ would be generated.

This work lays a theoretical foundation for tantalum as an excellent wear-resistant material.

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-02-2023-0047/