With the rapid advancement of cyber-physical systems, Digital Twin (DT) is gaining ever-increasing attention owing to its great capabilities to realize Industry 4.0. Enterprises from different fields ...are taking advantage of its ability to simulate real-time working conditions and perform intelligent decision-making, where a cost-effective solution can be readily delivered to meet individual stakeholder demands. As a hot topic, many approaches have been designed and implemented to date. However, most approaches today lack a comprehensive review to examine DT benefits by considering both engineering product lifecycle management and business innovation as a whole. To fill this gap, this work conducts a state-of-the art survey of DT by selecting 123 representative items together with 22 supplementary works to address those two perspectives, while considering technical aspects as a fundamental. The systematic review further identifies eight future perspectives for DT, including modular DT, modeling consistency and accuracy, incorporation of Big Data analytics in DT models, DT simulation improvements, VR integration into DT, expansion of DT domains, efficient mapping of cyber-physical data and cloud/edge computing integration. This work sets out to be a guide to the status of DT development and application in today’s academic and industrial environment.
To proactively fulfill multiple stakeholders’ needs in the engineering solution design process, the knowledge recommendation approach is adopted as a key element in the knowledge management system. ...Nevertheless, most existing knowledge recommendation approaches cannot simultaneously meet the higher standard of in-context accuracy and diversity. To address the issue, this paper proposes a context-aware diversity-oriented knowledge recommendation approach, thereby assisting stakeholders to accomplish engineering solution design in a smarter manner. Three diversity concerns, namely item-diversity, context-diversity, and user-diversity are addressed by semantic-based content analysis, context definition and awareness, and user profile modeling, respectively. Hence, the proposed approach not only maximizes the diversity of the recommended knowledge but also guarantees its accuracy under multiple problem-solving contexts. Moreover, a practical engineering solution design case on a Smart 3D printer platform is conducted, to validate the efficacy of the proposed approach in providing usable and diverse knowledge items. It is anticipated this work can provide useful insights to practitioners in their knowledge-based engineering solution design process.
Fermi's golden rule, a remarkable concept for the transition probability involving continuous states, is applicable to the interfacial electron‐transporting efficiency via correlation with the ...surface density of states (SDOS). Yet, this concept has not been reported to tailor single‐molecule junctions where gold is an overwhelmingly popular electrode material due to its superior amenability in regenerating molecular junctions. At the Fermi level, however, the SDOS of gold is small due to its fully filled d‐shell. To increase the electron‐transport efficiency, herein, gold electrodes are modified by a monolayer of platinum or palladium that bears partially filled d‐shells and exhibits significant SDOS at the Fermi energy. An increase by 2–30 fold is found for single‐molecule conductance of α,ω‐hexanes bridged via common headgroups. The improved junction conductance is attributed to the electrode self‐energy which involves a stronger coupling with the molecule and a larger SDOS participated by d‐electrons at the electrode‐molecule interfaces.
The conductance of molecular junctions bridged in Pt‐ or Pd‐adlayer modified Au electrodes was investigated. The conductance on bimetallic electrodes was found 2–30 fold higher than that on Au electrodes. This was attributed to the increase in the local density of states by partially‐filled d shells of the adlayer.
The contact at the molecule-electrode interface is a key component for a range of molecule-based devices involving electron transport. An electrode-molecule-electrode configuration is a prototypical ...testbed for quantitatively studying the underlying physical chemistry. Rather than the molecular side of the interface, this review focuses on examples of electrode materials in the literature. The basic concepts and relevant experimental techniques are introduced.
The study of metal string complexes with 1D transition‐metal frameworks began in the early 1990s. As these complexes provide great insights into metal–metal multiple bonds and may have potential ...applications as molecular wires, this field of research has grown in the past 20 years. As such, the electronic structures of the simplest trinuclear complexes, the supporting ligand systems, and the single‐molecular conductance of metal string complexes are discussed. This review introduces the development of this field and summarizes some important results in the newly designed heteronuclear metal string complexes (HMSCs). These molecules may be of great interest in studies of the nature of heterometallic electronic effects and molecular electronic applications.
This microreview describes the development of metal string complexes, from homonuclear to heteronuclear ones, including their synthesis and physical properties.
•Proposing a data-driven iterative design approach for smart product-service system.•Utilizing real-time data in the usage context to recommend personalized services.•Predicting satisfaction degree ...of all users by utilizing machine learning.•Using a new surgical robot for flexible ureteroscopy as an illustrative case.
As an emerging digital servitization paradigm, smart product-service system (Smart PSS) leverages smart, connected products and their generated services to work as a solution bundle to improve individual user satisfaction. As a complex solution bundle at both system and product level, its iterative design differs from the existing ones mainly in two aspects. Firstly, massive in-context data during the usage stage can be leveraged to calculate the satisfaction degree of individual users intelligently. Secondly, Smart PSS, consisting of both digitalized service and physical components, can be changed in a more flexible way in a data-driven manner. An iterative design method for fast positioning and replacing the unsatisfied modules can improve the user experience and extend the Smart PSS usage life. Nevertheless, some studies made attempts, and it is still missing an iterative design method with automatic real-time user satisfaction prediction. Aiming to fill this gap, this work proposes a machine learning-based iterative design approach to automate user satisfaction prediction in the Smart PSS environment. Furthermore, an illustrative case study of a surgical robot for flexible ureteroscopy is demonstrated along with this proposed methodological framework, which overcomes the challenges of subjectivity and tedious assessment of the experts in the conventional approaches. This research can offer some valuable guidelines to today’s industrial companies in Smart PSS development.
A record high PCE of up to 3.2% demonstrates that the efficiency of hybrid solar cells (HSCs) can be boosted by utilizing a unique mono‐aniline end group of PSBTBT‐NH2 as a strong anchor to attach to ...CdTe nanocrystal surfaces and by simultaneously exploiting benzene–1,3‐dithiol solvent–vapor annealing to improve the charge separation at the donor/acceptor interface, which leads to efficient charge transportation in the HSCs.
Eye movements as the indicators of human information processing have been studied in many domains. However, it is not clear how users’ eye movements differ among specific product attribute, while ...visual impression of a product plays a crucial part in distinguishing product designs. Therefore, this paper attempts to establish guidance for exploring eye tracking applications in design concept validations through two case studies. The first case study investigated the product attributes based on the theory of cognitive-affective emotions. The second investigated the product attributes for apparent functionality and affective quality. The eye movements of 105 participants were analyzed when they evaluated the products images. The results indicated that product attributes perceived in evaluation tasks can be predicted from eye movements. Moreover, compared to the new users, experienced users had a longer mean fixation duration and tended to form their impressions of the product from multiple components.
•Product attributes perceived in evaluation task can be predicted from eye movements.•Uncover links between users' visual processing style and product components.•Guidance for eye tracking applications in design concept validations.
This study aimed to evaluate the effect of anti‐pandemic measures, including wearing a face mask and receiving vaccinations, on interpersonal distance (IPD) during the normalization stage of the ...COVID‐19 pandemic. Virtual reality (VR) technology was used to simulate the experimental environment and a confederate in different conditions. Thirty‐one participants were asked to approach the virtual confederate, who could exhibit three vaccination states and two mask‐wearing conditions, actively and passively in both indoor and outdoor environments. ANOVA results showed that the participants kept a smaller IPD from the confederate wearing a face mask (IPD = 125.6 cm) than from the one without a face mask (IPD = 154.2 cm). The effects of vaccination states were significant, with the largest distance for an unvaccinated confederate (IPD = 182.3 cm) and the smallest distance for the confederate who had received a booster vaccine (IPD = 111.5 cm). Significant effects of environment were also found, with the participants maintaining a larger IPD in an outdoor environment (IPD = 143.4 cm) than in an indoor room (IPD = 136.4 cm). Additionally, the IPD collected when the participants were passively approached (IPD = 149.6 cm) was significantly larger than that obtained when they actively approached the confederate (IPD = 130.3 cm). Moreover, when the participants faced a confederate who had received a booster vaccine and wore a mask, the IPD was not significantly different from that collected before the COVID‐19 pandemic in both the active and passive patterns. These findings help us to better understand the nature of IPD and human behaviors during the normalization stage of the pandemic and provide scientific suggestions for policymakers to develop pandemic‐prevention measures.
Antiaromatic compounds have recently received considerable attention because of their novel properties such as narrow HOMO–LUMO gaps and facile formation of mutual stacking. Here, the spontaneous ...assembly of antiaromatic meso‐2‐thienyl‐substituted 5,15‐dioxaporphyrin (DOP‐1) is scrutinized at the liquid‐solid interface by scanning tunneling microscopy (STM). Polymorphism in monolayers characterized by the orthogonal and parallel assemblies is found at the low concentration of 0.05 mM. The parallel assembly is more stable and dominantly formed at higher concentrations. Aggregation was observed at concentrations >0.2 mM, and the STM images of the aggregates implied the formation of stacked layers. The intrinsic electronic structures of the mutually stacked bilayer generated by applying an electric pulse to the monolayer were probed by scanning tunneling spectroscopy to reveal the narrowing of the HOMO–LUMO gap by about 20 % compared with the monolayer, thus suggesting significant molecular orbital interactions.
The spontaneous assembly of antiaromatic meso‐2‐thienyl‐substituted 5,15‐dioxaporphyrin (DOP‐1) has been studied at the liquid‐solid interface to elucidate its polymorphism in a monolayer and the facile formation of the stacked layer. The study of the intrinsic electronic structures of the stacked bilayer by scanning tunneling spectroscopy revealed a narrowing of the HOMO–LUMO gap compared to the monolayer, thus suggesting significant molecular orbital interactions.
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