Genetic algorithm-enabled quantitative characterization of planar defect using local resonance frequency and attenuation.

Ring-excited unimorph ultrasonic transducer with double acoustic black hole structure for enhanced vibration radiation

The structural characteristics of magneto-plasmonic crystals (MPCs) play a critical role in their performances, but current research often focuses on specific applications with fixed structural designs, leaving a gap in the systematic understanding of how geometric parameters influence their magneto-optical (MO) properties, particularly the evolution and underlying mechanisms of Faraday effects. To address the issue, this study employs the finite-difference time-domain method to numerically investigate the extraordinary optical transmission and MO properties of MPCs composed of a perforated Au film on a bismuth-substituted yttrium iron garnet layer. The influence of key structural parameters-including film thicknesses, hole size, shape (circular/square), periodicity, and arrangement (single/double holes per unit cell)-on the transmission spectra, Faraday rotation, and electric field distribution is systematically analyzed. For single-hole arrays, the optimal circular-hole arrays achieve a transmission of 27.3% and a Faraday rotation of 0.69°, while the optimal square-hole arrays yield 26.2% transmission and 0.67° rotation. Double-hole arrays, particularly with square holes, exhibit enhanced transmission sensitivity to environmental refractive index changes, reaching 174.61 nm/RIU, compared to 113-115 nm/RIU for single-hole structure. Electric field analysis reveals that enhanced coupling between surface plasmon polaritons and localized surface plasmon resonances underpins the improved MO performance. The study demonstrates that while double-hole arrays offer higher sensing sensitivity, single-hole arrays provide a larger figure of merit for MO applications. These findings provide valuable guidelines for designing high-performance MPC devices and plasmonic sensors by elucidating the relationship between structural geometry and performance.

Abstract Holes and cracks can form at the bottom or inside of a structure due to the influence of external forces. They can also appear during processes such as exploration drilling and pipeline installation, and fatigue cracks or local separation may occur due to natural phenomena. Defects like hidden holes and cracks are often detected using ultrasonic waves. Detecting such defects typically requires expensive equipment or multiple transducers, but in this study, we develop a novel detection system for hidden holes, utilizing a single ultrasonic transducer and applying a piecewise nonlinear approximating transformation (PNAT) method combined with modal assurance criterion (MAC). The present study aims to detect the hidden holes in relatively large-scale specimens (300 mm × 100 mm × 100 mm) utilizing information from small-scale specimens (300 mm × 50 mm × 50 mm) along with some assumptions. To implement the proposed method, reflected longitudinal waves are analyzed and employed. A signal processing method is developed and applied to mitigate the influences of the DC components and noises in the measured ultrasonic signals. The filtered signals are then approximately classified through the PNAT process. Finally, various shapes and temperature conditions of hidden holes are evaluated using the MAC method. To validate the proposed approach, several experimental examples considering various diameters, angles and temperatures are conducted. As a result of the validation, the large-scale specimen cases including diameter cases of 13 mm, 7 mm and 4 mm, angle cases of 140 °, 120 ° and 100 °, and temperature cases of -30 °C, 30 °C and 100 °C could be classified and detected within relative errors of 5.6 %, 4.5 % and 6.3 %, respectively, compared with the reference signals of lab-scale specimens.

ABSTRACT This study examines the effect of financial strategic alliances (FSAs) on firms' risk‐taking, We find that FSAs increase risk‐taking, but this effect disappears after FSA termination. Mechanism analysis shows that FSAs increase firms' risk‐taking by alleviating financing constraints and reducing agency costs. This effect is stronger for non‐state‐owned entities and firms operating in highly competitive industries. It is also stronger for firms that acquire more resources within the FSA network (with larger structural holes and higher indegree in the network), and for those adopting bilateral strategic agreements or specifying the cooperation duration in the alliance terms.

This study investigates the impact of network structural characteristics on sustainable innovation performance within regional collaborative networks in China’s artificial intelligence (AI) industry. Provincial-level innovation networks were constructed and analyzed using social network analysis to trace their evolutionary pathways using patent application data from 2010 to 2024. The findings reveal that China’s AI innovation network has developed into a multi-tiered, polycentric structure with Beijing as the primary hub. An inverted U-shaped relationship was identified between network centrality, structural holes, and regional collaborative innovation performance at various developmental stages. The external institutional environment, particularly through government R&D subsidies and intellectual property protection, plays a significant moderating role, generally diminishing the effect of centrality while enhancing that of structural holes during the rapid expansion phase. Regional heterogeneity analyses confirmed these patterns in eastern, central, and western China, whereas in the northeast, only centrality showed a significant association with performance. By integrating network location theory with an institutional perspective, this study offers a dual-perspective framework for understanding how sustainable innovation ecosystems can be fostered through network governance and policy interventions. The results provide evidence-based policy implications aimed at enhancing collaborative innovation capacity, mitigating regional disparities, and advancing sustainable development.

The utilization of tuned mass dampers (TMDs) is subject to numerous restrictions. In general, the control performance of a TMD is limited by the ratio of the mass block to the effective mass of the main structure (mass ratio). These dampers also require precise tuning to the required target frequency to absorb the host structure’s vibrational energy. Due to their unique geometric gradient forms, acoustic black hole (ABH) structures can slow the propagation speed of bending waves and concentrate them at the apex, thereby significantly enhancing the suppression of broadband vibration. In this paper, we combine the above two methods to form a single novel device named ABH-TMD. Firstly, a mechanical model of the proposed device is established. The bending-wave control equation is derived, followed by a numerical analysis and experimental tests for further verification. Secondly, a series of numerical simulations are conducted. The response of the controlled beam is determined based on time histories and the frequency domain. Lastly, parameter analysis is carried out to investigate the control’s effectiveness. Based on the numerical and experimental results, we conclude that the proposed ABH-TMD can successfully concentrate elastic waves, thereby surpassing the traditional TMD under broadband frequency conditions.

ABSTRACT Whereas organizational network studies infer employees’ agentic desires through observed network changes, we capture desires to collaborate more closely with co‐workers directly through a survey. We argue that formal structures create workflow dependencies between employees as they gather others’ inputs to complete their tasks, and individuals desire to alter their networks to manage those dependencies using the following two main collaborative approaches: (1) collaborating more intensely with existing formal workflow network partners; and (2) engaging in bypassing approaches with specific partners outside of their prescribed formal workflow. We found that employees pursued a tie‐strengthening approach with formal partners they already trusted to provide high‐quality work inputs in a reliable manner. When using the bypassing approach, employees’ choice of desired partners reduced their workflow dependencies on alters upstream in the formal workflow, detouring around them either by choosing an alter that was structurally equivalent to existing partners or moving two steps further upstream to choose alters that close disadvantageous structural holes, suggesting these potential greater collaboration ties had higher latent structural value . Our study illustrates agentic desires toward dealing with the formal workflow's dependencies through the choice of specific partners with whom to collaborate more closely in the future, using tie‐strengthening and bypassing approaches.

Abstract This study examines how social embeddedness and multiplex relationships shape criminal collaboration within organized crime networks. Drawing on data from three major investigations into the ‘Ndrangheta, we analyze how kinship, clan affiliation, leadership, and prior interactions influence participation in meetings and phone calls. Using relational hyperevent models, we assess the dynamic and multiplex nature of these networks across time and investigations. Results show that kinship, leadership, and shared clan affiliation consistently increase the likelihood of interaction, with stronger effects for face‐to‐face meetings. Prior joint interactions also predict future collaboration, especially when the mode remains consistent. We find contrasting patterns of closure: meetings resist triadic closure, reinforcing exclusivity and hierarchy, whereas phone calls promote connectivity by bridging structural holes. By modeling multiple relational mechanisms simultaneously and across different networks, this study contributes to research on criminal embeddedness and the structural organization of illicit collaboration.

Magnetic pulse welding based on a field shaper using a single-turn multi-layer flat coil and enhancing the magnetic field in local areas with the field shaper can achieve point welding of metal sheets, with broad application prospects in dissimilar metal welding. By reasonably optimizing the structural parameters of the flat coil and the field shaper, the magnetic field strength and eddy current density in the local area can be effectively improved, thereby increasing the Lorentz force to improve the collision speed of the sheet, and ultimately improving the welding quality of the sheets. In view of this, the goal of this work was to maximize magnetic pressure, optimize the structural parameters of the flat coil and field shaper, and innovatively propose a new type of field shaper with an arc-shaped hole structure, which effectively improved the welding quality without changing the welding energy. Furthermore, a magnetic pulse spot welding (MPSW) experimental platform was built using the optimized magnet device, achieving the spot welding of AA1060 aluminum sheets and stainless steel (SS304) sheets both with a thickness of 1mm. Through peeling and stretching experiments, it was proven that the strength of the welded joint exceeded that of the base metal, indicating that the effective welding of dissimilar metals has been achieved. In addition, through microscopic analysis, it could be seen that a waveform composite interface was formed at the welding interface, which further indicated that the welding performance of the welded joint was good. The results indicated that the use of the new field shaper with an arc-shaped hole structure could reduce the critical discharge voltage for effective welding by 2kV, directly converting it into lower energy consumption requirements and a wider process window, which had important economic value for industrial applications.

ABSTRACT The previous research has overlooked the impact of technological linkages between key inventors in acquiring firms and target firms on individual creativity. Therefore, this study analyses 145 technological mergers and acquisitions (TMAs) conducted by Chinese high‐tech listed companies. Using patent data, this research constructs inventor networks for acquiring firms during the 3 years prior to and 3–5 years after the mergers. It examines how different types of technological relatedness between acquiring and target firms influence individual creativity. The analysis employs two dimensions of network positions—network centrality and structural hole—as mediating variables. The results reveal that technological complementarity between key inventors in acquiring firms and target firms significantly enhances the creativity of key inventors. Furthermore, network centrality and structural hole mediate the relationship between technological complementarity and the creativity of key inventors. This study extends the application of social network theory in the context of TMAs, providing new insights into how different types of technological relatedness affect the creativity of key inventors in acquiring firms.

ABSTRACT Environmental, Social, and Governance (ESG) performance has become a crucial factor in determining a firm's resilience and strategic agility in the evolving capital markets environment. This study examines how ESG practices contribute to organizational resilience through the mediating role of dynamic capabilities and the moderating effect of social network embedding, operationalized via board directors' social capital (centrality and structural holes). The proposed framework is tested using moderated mediation models on panel data from 7560 A‐share companies listed on the Shanghai and Shenzhen stock markets from 2013 to 2022. The findings demonstrate three major findings. First, ESG performance significantly enhances firms' dynamic capabilities, which include innovation, adaptation, and absorptive capacity, thereby strengthening their resilience to external shocks. Second, a stronger board network position amplifies the ESG‐capability link. Third, heterogeneity analyses reveal that the ESG‐resilience nexus is more pronounced in eastern regions, among large‐scale firms, non‐state‐owned enterprises, and in post‐pandemic periods. According to the study, ESG is a strategic resource. It highlights the role of director networks in the process of utilizing ESG investments to promote the long‐term sustainability of organizations. These results can contribute to the body of research on dynamic capabilities and stakeholder governance by providing a cross‐level model that incorporates sustainability, network theory, and resilience in emerging market environments.

Purpose This study examines the relationships among Structural Holes (SHs), Chinese Cooperative Culture (CCC) and Tacit Knowledge Integration (TKI) during corporate crises. It further explores the governance mechanism through which knowledge workers construct Transactive Memory Systems (TMS) to facilitate TKI. Design/methodology/approach We employed a mixed-methods approach comprising two studies. Study One combined empirical modeling (792 questionnaires and social network analyses) and scenario experiments (200 participants) to test two hypotheses. Study Two used focused ethnography (55 direct observations, 217 archival documents and 81 semi-structured interviews) to explore the governance mechanism. Findings Our findings show that SH impede TKI during corporate crises. However, CCC moderates this relationship in an inverted U-shape: TKI is highest at moderate SH levels but decreases when SH are either too many or too few. Knowledge workers construct TMS to facilitate TKI through six micro-processes (relational connection, expertise elicitation, affective commitment, cognitive convergence, knowledge synthesis and contextual deployment) across three stages (specialization, credibility and coordination). Originality/value This study makes four contributions: (1) We fundamentally challenge the static, asset-based view of IC treating human, structural and relational capital as passive repositories awaiting extraction by theorizing IC as a crisis-driven network resource dynamically governed through culturally embedded structural mechanisms. (2) We expose culture not as peripheral but as the institutional logic legitimizing IC flows across structural divides, where CCC’s tripartite moral economy resolves brokerage legitimacy paradoxes and enables SH as prosocial governance conduits. (3) We operationalize IC’s “black box” via a granular governance mechanism that transforms structural and cultural resources into crisis resilience. (4) We develop a structure-culture matrix diagnostic tool and cognitive calibration protocols to dynamically align SH density with CCC intensity, optimizing tacit IC mobilization during crises.

Conventional tourism planning in ecologically fragile regions often adopts a reductionist perspective, failing to address the synergistic spatial interactions between ecological conservation, resource utilization, and infrastructure. To bridge this gap, this study develops a multi-constraint synergistic assessment framework for the dry-hot valley of Lujiang Dam (LJD) in China. Grounded in the understanding of rural tourism as a complex adaptive system, the framework innovatively integrates the InVEST model, kernel density estimation, and cumulative cost-distance algorithms to identify Natural Spatial Suitability for Tourism Development (NSSTD). Key findings include (1) pronounced spatial heterogeneity in habitat quality, with high-quality zones in the west/southeast requiring strict conservation; (2) a “barbell-shaped” clustering of natural/cultural resources at the valley’s northern and southern extremities, highly congruent with ethnic settlements; and (3) a “concentric layered” accessibility pattern where 88.08% of resources are within a 90 min drive. Crucially, the spatial overlay analysis revealed that NSSTD (54.74 km2) emerges not from single high-value zones but from areas of synergy, such as those with medium habitat quality coupled with high resource endowment and accessibility. These results provide a scientifically robust, spatially explicit layer for China’s “Multi-plan Integration” territorial spatial planning. They enable differentiated strategies—channeling development to southern corridors, implementing niche tourism in northern “structural hole” villages, and enforcing conservation in western habitats—thereby offering a replicable methodology to balance ecological integrity with sustainable rural development.

Abstract An overview of nonlinear electrostatic structures in a collisionless plasma is given, as described by its three Schamel-type evolution equations. Separated in the phase velocity, these equations are related to the three acoustic modes of a two-component plasma, namely ion acoustic, the slow electron acoustic, and the slow ion acoustic mode. In their derivation, a novel coupling method is used that combines the propagation part with the structural part of the coherent wave pattern, with the focus on the exact reproduction of the kinetic equilibrium structures of the Vlasov–Poisson (VP) system. This is where the two central elements of Schamel’s equilibrium theory come into play, the nonlinear dispersion relation and the pseudo-potential. Various aspects such as existence, linearity, particle trapping scenario, non-negativity and stability are investigated and the corresponding fundamentals are conveyed. These include the correct understanding of the linear limit as distinct from the linear Vlasov limit and the alleviation of the positivity problem associated with the square root nonlinearity $$\sqrt{\phi }\partial _x\phi$$ by introducing appropriate pedestals for the electrostatic potential $$\phi (x,t)$$ . A general proof for the existence of solitary ion hole solutions over the entire temperature range is presented: $$0<\theta =\frac{T_e}{T_i} < \infty$$ , which corrects and extends the more restrictive condition $$\theta \le 3.5$$ used in the literature. Ion holes can therefore also exist for hotter electrons. The stability of a solitary electron hole, based on the S-equation, which focuses on a specific macroscopic structural behavior beyond kinetics, and a previous transverse but limited VP instability analysis, exhibits marginal longitudinal stability. The associated linear perturbations are in the form of the asymmetric shift eigenmode of a solvable Schrödinger problem. This finding of the possible dominance of the shift mode perturbation provides a new hint for the anticipated general kinetic proof of marginal stability and transverse instability of electrostatic structures under these conditions including undisclosed potentials.

Abstract In this analysis, we study the thermodynamic properties, phase structure, and critical behavior of a nonlinear electrodynamics charged black hole. Considering both the grand canonical and canonical ensembles, we employ the Bekenstein entropy and its non-extensive R é nyi generalization. The R é nyi parameter rescales the temperature and modifies the response functions, thereby shifting the stability windows and critical points. In the extended phase space, we derive a modified Smarr relation and the associated equation of state. Heat capacity divergences indicate second-order transitions, while the free energy structure exhibits first-order small-large black hole transitions: a Hawking-Page type transition in the grand canonical ensemble and a Van der Waals-like swallowtail in the canonical ensemble.

We demonstrate a novel plasma process capable of etching the ONON (silicon oxide/silicon nitride) hole structure for manufacturing 3D-NAND devices with a depth beyond 10 μm and an aspect ratio of approximately 100. The process utilizes hydrogen fluoride (HF) and a phosphorus-containing gas under cryogenic conditions in a dual-frequency capacitively coupled plasma chamber. To investigate the plasma-surface interactions at cryogenic temperatures, we performed in situ quadrupole mass spectroscopy measurements and density functional theory calculations. We found that the surface co-adsorption of the H2O by-product and the HF etchant at cryogenic temperatures and the additional enhancement of H2O adsorption by phosphorus-containing species produced from admixing a few percentage of a phosphorus-containing gas are key factors to enhancing the etch rate. This novel process has achieved dramatic productivity improvement compared with conventional fluorocarbon-based plasma etching processes, thus enabling the formation of ultra-high-aspect-ratio etching features for next-generation semiconductor device manufacturing.

With the gradual refinement of the division of labor in the market, suppliers in the upstream of the supply chain and customers in the downstream have become increasingly closely connected, forming a supply chain network among firms. As one of the important components of the social network in which firms are located, the supply chain network also affects the innovation activities of firms. Under the severe situation of “bottlenecking” of key common technologies in the industry, it is especially important to study the innovation effect and mechanism of the embedded position of firms in the supply relationship structure. In this theoretical and practical context, this study focuses on collecting supply chain data of the biopharmaceutical industry, constructing a biopharmaceutical supply chain network, using tools such as UCINET for social network analysis, identifying key core common technologies of the biopharmaceutical industry based on patent data, and finally constructing and validating the research model. The research process mainly explores two key issues: firstly, the impact of firm centrality on firm General-Purpose Technologies (GPTs) innovation; and secondly, the impact of structural holes on firm General-Purpose Technologies.

Knowledge hiding, the deliberate withholding of knowledge, can undermine team effectiveness and organizational performance. However, little is known about its diffusion within organizational teams. Drawing on social contagion theory, this study uses Autologistic Actor Attribute Models (ALAAMs) to examine knowledge hiding across workplace and social communication networks. Whole-network survey data from 200 employees in 31 teams in the U.S. and China reveal that, overall, knowledge hiding does not spread through communication networks. Certain network structures, however, facilitate its transmission: individuals centrally connected to multiple teammates or embedded in closed triads with both a hider and a non-hider are more likely to hide knowledge, whereas those bridging structural holes between hiders and non-hiders tend to avoid it. These findings advance social contagion theory and knowledge hiding research by showing how norm-violating behavior diffuses across different network structures and by characterizing knowledge hiding as network-embedded rather than solely an individual act.

The study of black holes originated at the forefront of theoretical physics. In the early years, researchers such as Carl Schwarzschild and John Michell proposed early theories related to black holes, which were later supported by observational data. This article first dissects the key scientific concepts of black holes - such as event horizons, singularities, and their impacts on the surrounding spacetime; At the same time, it traces the historical evolution of black hole research and presents in its entirety the entire process from "theoretical conception" to "observational evidence". In recent years, with the development of key technologies such as the Event Horizon Telescope (EHT) and gravitational wave astronomy, human research on black holes has witnessed significant breakthroughs: Nowadays, we can directly "observe" the existence of black holes, and by studying the interaction between black holes and matter and other means, we can gain a deeper understanding of the overall evolution of the universe, the evolution of individual galaxies, and the internal structure of black holes themselves.