Search Results (83)

A novel reflective metasurface (RMS) is proposed in this paper. The MS measures 128 × 128 × 2.794 mm³ and consists of a six-layer vertically stacked structure, with a liquid crystal (LC) cavity in the middle layer. A dual fan-shaped direct current (DC) bias circuit is designed to minimize the interaction between the radio frequency (RF) signal and the DC source, allowing control of the LC dielectric constant via bias voltage. This enables multi-band operation to improve communication capacity and quality for x-band devices. The polarization conversion (PC) structure employs an orthogonal anisotropic design, utilizing logarithmic functions to create two pairs of bowtie microstrip patches for linear-to-circular polarization conversion (LCPC). Simulation results show that for x-polarized incident waves, with an LC dielectric constant of ε_r = 2.8, left- and right-handed circularly polarized (LHCP and RHCP) waves are achieved in the frequency ranges of 8.15–8.46 GHz and 9.84–12.52 GHz, respectively. For ε_r = 3.9, LHCP and RHCP are achieved in 9–9.11 GHz and 9.86–11.81 GHz, respectively, and for ε_r = 4.6, they are in 8.96–9.11 GHz and 9.95–11.51 GHz. In the case of y-polarized incident waves, the MS reflects the reverse CP waves within the same frequency ranges. Measured results show that at ε_r = 2.8, the axial ratio (AR) is below 3 dB in the frequency ranges 8.16–8.46 GHz and 9.86–12.48 GHz, with 3 dB AR relative bandwidth (ARBW) of 3.61% and 23.46%, respectively. For ε_r = 4.6, the AR < 3 dB in the frequency range of 9.78–11.34 GHz, with a 3 dB ARBW of 14.77%. Finally, the measured and simulated results are compared to validate the proposed design, which can be applied to various applications within the corresponding operating frequency band. Full article

This research was designed to explore science-fiction and fantasy (SFF) posters, specifically those related to films and television shows, from the perspective of their owners, examining their potential as sources of social and cultural significance and meaning. The research explored these in terms of the content of the poster, placement, media texts they reference, morals, behavior, identity, sense of self, well-being and self-expression. Data collection took place between 2020 and 2022 via an online survey (N = 273) and follow-up semi-structured interviews (N = 28) with adult science-fiction and fantasy film and television show poster owners. The significance and meaning of SFF posters were framed by two conceptual models: ‘The Three Significances’—esthetics, functionality, and significance (both spatial and personal)—and ‘The Big Three’—content, design, and color. Among these, content held the greatest significance for owners. Posters served as tools for self-expression, reflecting their owners’ identities, affinities, and convictions, while also reinforcing their connection to the media they reference. Posters helped to reinforce a sense of self and fan identity and evoke emotional responses, and the space in which they were displayed helped shape their meaning and significance. The paper sets out some suggestions for future research in this important topic. Full article

The geometric structure design of three-layer hollow fan blades is extremely complex, which is not only directly related to the blade quality and manufacturing cost but also has a significant impact on engine performance. Based on geometric algorithms and combined with design rules and process constraints, an intelligent design method for the geometric structure of three-layer hollow blades is proposed: A new cross-section curve design method based on a non-equidistant offset is presented to enable the rapid design of wall plate structure. An innovative parametric design method for the corrugation structure in cross-sections driven by process constraints such as diffusion bonding angle thresholds is put forward. The spanwise rib smoothing optimization is realized based on the minimum energy method with the corrugation angle change term. The cross-section densification design is carried out to improve the accuracy of wireframe structure and achieve the rapid solid modeling of hollow blades. Finally, the proposed methods are seamlessly integrated into the NX software (version 12), and a three-layer hollow fan blade intelligent design system is developed, which enables the automated design and modeling of the complex geometric structure of the hollow blade under an aerodynamic shape and a large number of design and process constraints. Full article

Compared with the traditional rigid solar wings, flexible solar arrays are characterized by light weight and high stowing/deployment ratio, and the repeatable stowing/deployment flexible solar arrays have become one of the hotspots of solar arrays research in the aerospace field. As integrated rigid–flexible structures, flexible solar arrays face risks of repeatable stowing/deployment function failure due to the nonlinear force-heat coupling effects. This paper takes symmetry as the core design concept, and through the introduction of rotationally symmetric sector layout, material stacking, and the stowing/deployment mechanism, the thermal response of flexible solar arrays under extreme thermal environments was systematically investigated, which significantly improves thermal distribution uniformity of the flexible solar arrays and provides a new way of solving the problem of repeatable stowing/deployment of flexible solar arrays. Furthermore, we propose a high- and low-temperature unfolding test method for fan-shaped flexible solar arrays, which verifies the reliability of symmetric fan-shaped arrays in high and low temperatures during the working process of repeatable stowing/deployment and the safety of the stowing/deployment process, as well as providing a reference for the subsequent design and test of flexible solar arrays of other configurations. Full article

As digital fandom communities expand and diversify, user engagement patterns increasingly shape the social and emotional fabric of online platforms. In the era of Industry 4.0, data-driven approaches are transforming how online communities understand and optimize user engagement. In this study, we examine how different forms of activity, specifically posting and commenting, characterize fandom engagement on Weverse, a global fan community platform. By applying a clustering approach to large-scale user data, we identify distinct subsets of heavy users, separating those who focus on creating posts (post-heavy users) from those who concentrate on leaving comments (comment-heavy users). A subsequent linguistic analysis using the Linguistic Inquiry and Word Count (LIWC) tool revealed that post-heavy users typically employ a structured, goal-oriented style with collective pronouns and formal tones, whereas comment-heavy users exhibit more spontaneous, emotionally rich expressions enhanced by personalized fandom-specific slang and extensive emoji use. Building on these findings, we propose design implications such as pinning community-driven content, offering contextual translations for fandom-specific slang, and introducing reaction matrices that address the unique needs of each group. Taken together, our results underscore the value of distinguishing multiple dimensions of engagement in digital fandoms, providing a foundation for more nuanced platform features that can enhance positive user experience, social cohesion, and sustained community growth. Full article

Exploring the diversity and community structure of darkling beetles (Tenebrionidae) and the associated environmental factors on an alluvial fan provides useful insights into the ecology of these landscape features. This study investigated Chaqikou in the Helan Mountains, which features unique alluvial fan landforms. Sample plots (200 × 200 m) were established at three positions: the fan top, fan middle, and fan edge. From May to October 2023, pitfall traps were used to survey beetle community composition and its relationship with environmental factors. Significant variations were observed in species composition and diversity indices across different months and sample plots. Strongly xerophilous species exhibited broader ecological niche breadth, while moderately xerophilous species tended to distribute in the mid-to-upper segments of alluvial fans. Non-metric multidimensional scaling analysis revealed temporal shifts in community composition, with beta diversity analysis showing that species nestedness dominated from June to August, while species replacement was prominent in May, September, and October. Redundancy analysis indicated that environmental factors affecting species distribution varied by plot. On the landscape scale, altitude was the primary factor affecting beetle distribution. Variance partitioning analysis showed that topographic, soil, and vegetation factors explained 51.7%, 20.2%, and 9.4% of the variation in the beetle community, respectively. It is evident that altitudinal gradients shape ecological filtering pressures by creating multidimensional heterogeneity in topography, soil properties, and vegetation coverage. The adaptive matching between Tenebrionid species’ biological traits and environmental factors ultimately governs the spatial distribution patterns of darkling beetle diversity in alluvial fan desert grasslands. Full article

Large curvature, high pre-swirl large high-speed centrifugal fans are the preferred choice for industrial gas quenching furnaces, as they need to operate under non-uniform inlet conditions for extended periods. The resulting inlet distortion disrupts the symmetric flow of the gas, leading to reduced fan stability and phenomena such as flow separation and rotational stall. This issue has become a key research focus in the field of large centrifugal fan applications. This paper introduces an eddy viscosity correction method, and compares it with experimental results from U-shaped pipe curved flow. The corrected SST k-ω model shows a maximum error of only 4.7%. Simulation results show that the fan inlet generates a positive pre-swirl inflow with a relative distortion intensity of 3.83°. The flow characteristics within the impeller passage are significantly affected by the swirl angle distribution. At the maximum swirl angle, the leakage flow at the blade tip develops into a stall vortex that spans the entire passage, with an average blockage coefficient of 0.29. At the minimum swirl angle, the downstream leakage flow at the blade tip is suppressed on the suction side by the main flow, leading to a reduced vortex structure within the passage and an average blockage coefficient of 0.21. To address the design challenges of large high-speed centrifugal fans under inlet distortion, a blade design method based on secondary flow suppression is proposed. Eleven impeller flow surfaces are selected as control parameters, and the centrifugal impeller blade profile is redesigned. Numerical simulations and experimental results of the gas quenching furnace’s flow and temperature fields indicate that the modified impeller significantly reduces the blade tip leakage flow strength, with the average blockage coefficient decreasing to 0.07 and 0.04, respectively. The standard deviation of the average flow velocity at the test section is reduced by 42.78% compared to the original, and the temperature fluctuation at the workpiece surface is reduced by 53.09%. Both the flow and temperature field uniformity are significantly improved. Full article

In the evolving landscape of fandom economics, fan-driven crowdfunding has emerged as a powerful force, transforming audiences from passive consumers into active participants in celebrity branding. This study examines the roles of trust, loyalty, and perceived value in shaping crowdfunding participation within Chinese Weibo K-pop communities, where fans collectively finance large-scale public advertisements for their idols. Using structural equation modeling (SEM) on survey data from 260 participants, our findings reveal that trust and loyalty within fan communities significantly enhance engagement in crowdfunding activities, reinforcing perceived idol value and financial commitment to promotional campaigns. These insights position fan crowdfunding as a key driver of digital-era consumer culture, illustrating its impact on idol branding, online community dynamics, and the monetization of fandom engagement. By bridging fandom studies, digital marketing, and behavioral economics, this research provides theoretical advancements and practical strategies for entertainment agencies and celebrity managers seeking to harness the economic power of fan-driven marketing. As fandoms continue to reshape traditional advertising models, understanding the mechanisms behind community-based crowdfunding offers new avenues for brand engagement, audience monetization, and sustainable fan participation in the global entertainment industry. Full article

Tip leakage flow interacts with the mainstream, impacting the energy transmission process within the impeller of the fan and causing a significant flow loss. Understanding the flow characteristics within the impeller is a prerequisite and foundation for achieving efficient operation of the fan. Therefore, numerical simulations and experimental methods were employed to obtain the internal flow field of the mining counter-rotating axial flow fan, and the influence of flow rate on the tip leakage flow pattern was mastered. The spatial trajectory of the leakage vortex was quantified, and the distribution characteristics of the backflow were explored. The mechanism of energy loss caused by the leakage flow was revealed. The research findings indicate that when the flow rate exceeds 1.0 Q_BEP (Q_BEP is flow rate at the best efficiency point), the complex flow field near the blade tip is mainly caused by the tip leakage flow. However, the tip leakage flow and the leading edge overflow are the main factors causing disturbances in the flow field within the impeller at small flow rates. At large flow rates, the starting positions of the tip leakage vortex cores for both the front and rear impellers are located near the middle of the blade tip. As the flow rate decreases, the starting position of the vortex core gradually shifts toward the leading edge point, and the vortex structure evolves from an initial circular shape to an elliptical shape. The tip leakage flow and the leading edge overflow are the main cause of the backflow at the impeller inlet. The helical vortices caused by the tip leakage flow and the leading edge overflow, as well as the backflow in the impeller, are the key factors causing energy loss in the tip clearance flow field. Full article

The quad-helix and W-arch are commonly used appliances for expanding the dental arch in orthodontic treatment. However, differences in performance between these two expanders remain unclear, and no guidelines exist for selecting one over the other. The purpose of this study was to investigate whether there were differences in dental arch expanding ability between these appliances. Maxillary arch expansions were simulated using the finite element method. The expander was assumed to be an elastic beam, while the teeth and alveolar bone were treated as rigid bodies. The periodontal ligament (PDL) was modeled as a nonlinear elastic material. The teeth moved in the same direction as the initial movement caused by the elastic deformation of the PDL. The right and left canines, premolars, and first molars were expanded symmetrically in either parallel or fan shapes. When the wire diameter of the W-arch was set to 0.032 inches its stiffness became equivalent to that of a quad-helix with a wire diameter of 0.036 inches. Canines and premolars were expanded through tipping movements. The molars initially tipped buccally, then became upright and moved bodily. Both expanders expanded the arch in almost the same manner. There was no difference in arch expansion ability between the W-arch made of 0.032-inch wire and the quad-helix made of 0.036-inch wire. The W-arch may be preferred as the first choice due to its simpler structure compared to the quad-helix. Full article

A subway transfer station hall is crowded and complex in structure, which makes evacuation more difficult in case of a fire, but also provides more strategic options for smoke extraction. Full-scale experiments and numerical simulations are conducted to investigate the feasibility and performance of coordinated ventilation in a T-shaped transfer station hall, accounting for different fire source locations, ventilation modes, and fire shutter operations. It is found that the optimal ventilation strategy varies based on the fire location within the T-shaped configuration. For fires on the ‘T’s horizontal side, lateral airflow from longitudinal fans can effectively disrupt smoke spreading, with coordinated extraction strategies outperforming the traditional methods. However, for fires on the ‘T’s longitudinal side, horizontal fans are ineffective in controlling smoke flow, making the traditional fire shutter closure optimal. The idea of dispersing hot smoke to a reasonable degree can create better evacuation conditions for people near a fire, while creating almost no new danger zones. Full article

Microscopic evidence demonstrated a strictly biotrophic lifestyle of the scab fungus Venturia inaequalis on growing apple leaves and characterised its hemibiotrophy as the combination of biotrophy and saprotrophy not described before. The pathogen–host interface was characterised by the formation of knob-like structures of the fungal stroma appressed to epidermal cells as early as 1 day after host penetration, very thin fan-shaped cells covering large parts of the host cell lumen, and enzymatic cuticle penetration from the subcuticular space limited to the protruding conidiophores. The V. inaequalis cell wall had numerous orifices, facilitating intimate contact with the host tissue. Pathogen-induced modifications of host cells included partial degradation of the cell wall, transition of epidermal cells into transfer cells, modification of epidermal pit fields to manipulate the flow of nutrients and other compounds, and formation of globular protuberances of mesophyll cells without contact with the pathogen. The non-haustorial biotrophy was characterised by enlarged areas of intimate contact with host cells, often mediated by a matrix between the pathogen and plant structures. The new microscopic evidence and information on the pathogens’ biochemistry and secretome from the literature gave rise to a model of the lifestyle of V. inaequalis, lacking a necrotrophic stage that covers and explains its holomorphic development. Full article

In order to improve the inlet distortion of the squirrel-cage fan, this study proposes a parametric design method for the bionic structure of the inlet nozzle generatrix, which is spliced by multiple sinusoidal curves, based on the bionic structure of the humpback whale flipper leading-edge nodule. The geometric shape of the bionic generatrix is controlled by three parameters: the number of segments n, the amplitude ratio T_m, and the amplitude of the last curve A_n. These parameters are optimized through orthogonal tests and numerical simulations, with the aim of improving the fan’s aerodynamic efficiency. Based on the selected solution, a comparative analysis is conducted to examine the impact of cylindrical, conical, and bionic inlet nozzles on inlet distortion and flow evolution within the centrifugal fan. Numerical calculations demonstrate that the fan’s maximum total efficiency, with a bionic inlet nozzle designed in a rational manner, is 5.46% higher than that of the original fan and is 2.01% higher than that of the fan with a conical inlet nozzle. The proposed bionic structure can create a buffer zone at the fan’s inlet, thereby reducing the region of high vorticity caused by the separated flow. Consequently, this improvement leads to enhanced uniformity at the impeller’s inlet. Furthermore, the design method proposed in this study for the inlet nozzle’s bionic structure effectively regulates the airflow angle near the impeller shroud, thereby enhancing the fan’s inlet distortion and improving its overall aerodynamic performance. Full article

This paper aims to investigate the indoor environmental conditions and energy use behaviours of older individuals in rural cold climates of China, with a specific focus on cooling practices during the summer months in the Shandong region. This study employs a mixed-method approach, combining quantitative indoor environmental monitoring with qualitative interviews and observations, to explore the relationship between environmental factors, household living conditions, and energy use patterns across five types of elderly households: three generations living together, older people living with grandchildren, older people living with children, older couples living together, and older people living alone. Data collection was conducted over five weeks during the summer of 2023 using HOBO UX100-003 data loggers, while external weather conditions were monitored by the China Meteorological Administration. Face-to-face interviews were conducted to gain deeper insights into daily cooling behaviours and energy use. The results reveal that cooling practices and indoor environmental conditions vary significantly among the different household types. Multigenerational households showed more complex energy use dynamics, with younger family members frequently operating high-energy appliances like air conditioners, while older individuals tended to rely on natural ventilation and electric fans to reduce energy costs. In contrast, older couples and solitary older individuals demonstrated more conservative cooling behaviours, often enduring higher indoor temperatures due to limited financial resources and a desire to minimize energy expenditures. Despite the high energy use intensity in some households, many homes failed to achieve comfortable indoor environments, particularly in dwellings with minimal insulation and older building materials. This study concludes that economic status, household structure, and building characteristics play crucial roles in shaping cooling behaviours and indoor comfort during the summer. Full article

A dual fan-shaped structure covered with Ag films was investigated for generating twin photonic hooks (t-PHs). The t-PH characteristics of this structure are studied using the Finite-Difference Time-Domain (FDTD) method. The results show that by designing appropriate fan-shaped opening angles and angles of Ag films coverage, the switching between t-PHs, S-shaped t-PHs, and W-shaped t-PHs can be achieved, along with controlling over the bending angles. The maximum first, second, and third bending angles for the obtained W-shaped t-PHs are 51.3°, 36.4°, and 41.8°, respectively, while the Ag films angle is 5°. The investigated tunable morphology t-PHs provide innovative applications in the fields of nanolithography and integrated optics. Full article