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The aim of this study is to explore, identify and understand the impact of technology affordance in the context of social networking sites (SNSs). Moreover, this study incorporates user experience as a moderator, in order to explore behavioral differences between veterans (high-experience users) and newbies (low-experience users).

A research model was developed to examine the influences of three technology affordances: interactivity, information and navigation on user satisfaction and SNS stickiness. Totally 266 data were collected from a famous college in China using an online survey, and structural equation modeling technique was used to examine the proposed research model.

The empirical research findings indicated that the three technology affordance attributes exhibited different degrees of influence on user satisfaction, which in turn facilitated SNS stickiness. Particularly, high-experience users were more likely influenced by interactivity and information affordances, while low-experience users are more susceptible to navigation affordance.

This study can provide guidelines to the platform administrators to design SNSs from the aspects of interactivity, information and navigation attributes and pay attention to the preference differences between high-experience users and low-experience users.

This study uncovers the significant antecedents of SNS stickiness from a technology affordance lens and reveals the moderating effect of user experience on the relationship between three technology affordance attributes and satisfaction.

By distinguishing between core business service and value-added service in mobile payment applications, this paper aims to incorporate point mechanisms (point rewarding and point exchanging) into these two separated roles of services to understand user loyalty formation. Specifically, this study aims to examine the mediating role of need satisfaction and perceived value in the relationships between point mechanisms and user loyalty.

Drawing upon self-determination theory and perceived value lens, this study develops a theoretical model that examines the mediation effects of multiple psychological outcomes on the relationships between point mechanisms (point rewarding and point exchanging) and user loyalty in the context of mobile payment. Data were collected from 731 users of a leading mobile payment application in China through an online survey. Structural equation modeling was used to analyze the hypothesized relationships.

Empirical results suggest that point rewarding enhances users’ need satisfaction of core service, whereas point exchanging increases users' perceived value of additional value-added service. Results also reveal that need satisfaction and perceived value mediate the relationships between point mechanisms (i.e. point rewarding and point exchanging) and user loyalty. In sum, the findings enhance our understanding of user loyalty formation from a dual channeling perspective.

This study informs the managers of mobile payment applications on how to build user loyalty by enhancing users' experience of core business service and value-added service through point mechanism implementation.

This study highlights the importance of both core business service and value-added service in mobile payment applications and provides new insights into the effects of point mechanisms on user loyalty by considering different service routes. Additionally, this study uncovers the mediation mechanisms of users' need satisfaction of core service and users' perceived value of additional value-added service on the two service routes, which further enrich our understanding regarding the user loyalty formation of mobile payment applications.

The purpose of this paper is to demonstrate the effect of δ-ferrite on the susceptibility to hydrogen embrittlement of type 304 stainless steel in hydrogen gas environment.

The mechanical properties of as-received and solution-treated specimens were investigated by the test of tensile and fatigue crack growth (FCG) in 5 MPa argon and hydrogen.

The presence of δ-ferrite reduced the relative elongation and the relative reduction area (H₂/Ar) of 304 stainless steel, indicating that δ-ferrite increased the susceptibility of hydrogen embrittlement in 304 stainless steel. Moreover, δ-ferrite promoted the fatigue crack initiation and propagation at the interface between δ-ferrite and austenite. The FCG tests were used to investigate the effect of δ-ferrite on the FCG rate in hydrogen gas environment, and it was found that δ-ferrite accelerated the FCG rate, which was attributed to rapid diffusion and accumulation of hydrogen around the fatigue crack tip through δ-ferrite in high-pressure hydrogen gas environment.

The dependence of the susceptibility to hydrogen embrittlement on δ-ferrite was first investigated in type 304 steel in hydrogen environment with high pressures, which provided the basis for the design and development of a high strength, hydrogen embrittle-resistant austenitic stainless steel.

The purpose of this study is to address the welding demands within large steel structures by presenting a global spatial motion planning algorithm for a mobile manipulator. This algorithm is based on an independently developed wall-climbing robot, which comprises a four-wheeled climbing mobile platform and a six-degree-of-freedom robotic manipulator, ensuring high mobility and operational flexibility.

A convex hull feasible domain constraint is developed for motion planning in the mobile manipulator. For extensive spatial movements, connected sequences of convex polyhedra are established between the composite robot’s initial and target states. The composite robot’s path and obstacle avoidance optimization problem are solved by constraining the control points on B-spline curves. A dynamic spatial constraint rapidlye-xploring random trees-connect (RRTC) motion planning algorithm is proposed for the manipulator, which quickly generates reference paths using spherical spatial constraints at the manipulator’s end, eliminating the need for complex nonconvex constraint modeling.

Experimental results show that the proposed motion planning algorithm achieves optimal paths that meet task constraints, significantly reducing computation times in task conditions and shortening operation times in non-task conditions.

The algorithm proposed in this paper holds certain application value for the realization of automated welding operations within large steel structures using mobile manipulator.

Based on the perspective of knowledge management, this study aims to discuss how to build cross-city emergency management collaboration mechanism in major emergencies and explore the important role of knowledge management in emergency management collaboration.

Based on the theoretical analysis of knowledge management and the typical case study of cross-city emergency management collaborative rescue, this study provides an in-depth analysis of how these cities achieve high emergency management performance through multidimensional and multilevel knowledge collaboration, thus revealing the mechanism of knowledge transfer, integration and sharing in achieving high emergency management performance.

Through analyzing typical cases, this study finds that building a smooth mechanism for multichannel emergency rescue information can promote the diversification of knowledge transfer methods, building a platform-based integration mechanism for emergency rescue information can enhance knowledge integration capabilities and building a linkage mechanism for emergency rescue materials between cities can promote knowledge-sharing level, thereby improving emergency management performance level.

This study has great significance for how to build cross-city emergency management collaboration mechanism in the digital era. In the future, the authors need to further discuss the following two aspects in depth: research on the impact of cross-city emergency management collaboration mechanism on improving the knowledge management capabilities of government emergency management departments; and research on the impact mechanism of knowledge management capabilities on city resilience.

Through case analysis of cross-city emergency management collaborative rescue for major emergencies in China in recent years, this study proposes three specific strategies for cross-city emergency management (smooth, integration and linkage mechanisms) and reveals that these three strategies are essentially aimed at improving the government’s knowledge management level.

Despite smart construction technology's great potential to improve the productivity of the architectural, engineering and construction (AEC) industry, the implementation of smart construction technology has failed to achieve the expected benefits due to the negative usage behaviors of construction enterprise employees. This study aims to identify the determinants and their configuration effects on the smart construction technology usage behavior (SCTUB) based on the Technology-Organization-Environment (TOE) framework. This study then verifies the practical paths to improve the employee's SCTUB from the configuration perspective.

A mixed-method approach involving survey and qualitative comparative analysis (QCA) is conducted in this study. Based on the detailed literature review and semi-structured interview, this study identifies the factors and proposes the TOE framework to determine the configuration conditions affecting employee's SCTUB and verify practical paths to promote this user behavior.

The TOE framework's technical, organizational and environmental elements are interdependent. The emergence of a high SCTUB is not determined by a single determinant but by configuration conditions. Four equifinal conditions (e.g. organization-technology type, technology-organization type, environment type and organization-technology balanced type) are verified to promote construction enterprise employee's SCTUB.

The four verified configuration conditions could guide construction enterprises to formulate complementary strategies for promoting the construction enterprises' employees to implement smart construction technology and achieve the enterprise's digital transformation.

The inter-dependence of the three-dimension factors, namely technical, organizational and environmental elements are explored to enrich the literature on the TOE framework. Meanwhile, the configuration effects of these factors on usage behavior are identified, expanding the literature on the information technology acceptance model.

The authors have prepared the triazole film on copper surface by click reaction and explored its inhibition mechanism.

The protective film is assembled by immersing bronze in solution containing p-toluenesulfonyl azide (TA) and propiolic acid (PA).

Fourier transform infrared spectroscopy (FT-IR) indicates that triazole (TTP) film was formed on bronze surface via click chemistry reaction between TA and PA. It shows TTP film has a good protection for bronze in the atmospheric environment simulation solution. Quantum chemical calculation (QC) and molecule dynamics simulation suggests TTP molecule adsorbs on bronze surface via N and O.

This is beneficial to develop the corrosion inhibitors for the corroded copper alloys.

To maintain the well integrity, the strength and sealing ability of premium connection should be in the safe scope. ISO 13679 is widely used for evaluating the ability of tubing and casing connection all over the world. FE is adopted to simulate the ISO 13679 tests.

Because of the disadvantage of experiment such as long period, high cost and high requirement on the facility, considering the convenience and universality of finite element method, as well as the contacting nonlinearity and material nonlinearity, three-dimensional finite element model of a certain type of premium connection is established with the consideration of helix angle. The loads exerted on the premium connection are the loads in series B test and thermal cycle test of ISO 13679. The distributions of Von Mises stress and contact pressure in various cases were studied.

The results showed that the bending load has a great influence on the distribution of Von Mises stress and contact pressure for premium connection. The Von Mises stress and contact pressures on the sealing surface are smaller on the tension side and greater on the compression side. With increasing axial compression load, the contact pressures on the tension side are too small, which may lead to sealing failure. The influence of temperature on the performance of premium connection cannot be ignored when choosing or designing premium connections. Both the Von Mises stress and contact pressure decrease slightly during a period of thermal cycle. Although the performance of the premium connection is good in a period of thermal cycle, its performance in a long period should be evaluated. Finite element simulation can effectively simulate the ISO 13679 test procedure and obtain the stress and contact pressure distribution. It can be used as a reference for evaluating the performance of premium connections.

Considering the convenience and universality of finite element method, as well as the contacting nonlinearity and material nonlinearity, three-dimensional finite element model of a certain type of premium connection is established with the consideration of helix angle.

The purpose of this paper is to put forward a path planning method in complex environments containing dynamic obstacles, which improves the performance of the traditional A* algorithm, this method can plan the optimal path in a short running time.

To plan an optimal path in a complex environment with dynamic and static obstacles, a novel improved A* algorithm is proposed. First, obstacles are identified by GoogLeNet and classified into static obstacles and dynamic obstacles. Second, the ray tracing algorithm is used for static obstacle avoidance, and a dynamic obstacle avoidance waiting rule based on dilate principle is proposed. Third, the proposed improved A* algorithm includes adaptive step size adjustment, evaluation function improvement and path planning with quadratic B-spline smoothing. Finally, the proposed improved A* algorithm is simulated and validated in real-world environments, and it was compared with traditional A* and improved A* algorithms.

The experimental results show that the proposed improved A* algorithm is optimal and takes less execution time compared with traditional A* and improved A* algorithms in a complex dynamic environment.

This paper presents a waiting rule for dynamic obstacle avoidance based on dilate principle. In addition, the proposed improved A* algorithm includes adaptive step adjustment, evaluation function improvement and path smoothing operation with quadratic B-spline. The experimental results show that the proposed improved A* algorithm can get a shorter path length and less running time.

This paper aims to quickly obtain an accurate and complete dense three-dimensional map of indoor environment with lower cost, which can be directly used in navigation.

This paper proposes an improved ORB-SLAM2 dense map optimization algorithm. This algorithm consists of three parts: ORB feature extraction based on improved FAST-12, feature point extraction with progressive sample consensus (PROSAC) and the dense ORB-SLAM2 algorithm for mapping. Here, the dense ORB-SLAM2 algorithm adds LoopClose optimization thread and dense point cloud map and octree map construction thread. The dense map is computationally expensive and occupies a large amount of memory. Therefore, the proposed method takes higher efficiency, voxel filtering can reduce the memory while ensuring the density of the map and then use the octree format to store the map to further reduce memory.

The improved ORB-SLAM2 algorithm is compared with the original ORB-SLAM2 algorithm, and the experimental results show that the map through improved ORB-SLAM2 can be directly used in navigation process with higher accuracy, shorter tracking time and smaller memory.

The improved ORB-SLAM2 algorithm can obtain a dense environment map, which ensures the integrity of data. The comparisons of FAST-12 and improved FAST-12, RANSAC and PROSAC prove that the improved FAST-12 and PROSAC both make the feature point extraction process faster and more accurate. Voxel filter helps to take small storage memory and low computation cost, and octree map construction on the dense map can be directly used in navigation.