Natural creatures and ancient cultures are full of potential sources to provide inspiration for applied *** by the fractal geometry in nature and the fretwork frame in ancient culture,here we design the acoustic metas...
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Natural creatures and ancient cultures are full of potential sources to provide inspiration for applied *** by the fractal geometry in nature and the fretwork frame in ancient culture,here we design the acoustic metasurface to realize sound anomalous modulation,which manifests itself as an incident-dependent propagation behavior:sound wave propagating in the forward direction is allowed to transmit with high efficiency while in the backward direction is obviously *** quantitatively investigate the dependences of asymmetric transmission on the propagation direction,incident angle and operating frequency by calculating sound transmittance and energy *** compact fractal fretwork metasurface for acoustic anomalous modulation would promote the development of integrated acoustic devices and expand versatile applications in acoustic communication and information encryption.
A high-sensitivity cavity ring-down spectroscopy gas detection system with integrated optical components and embedded microprocessor units is presented for the detection of hydrogen sulfide(H_(2)S)in sulphur hexafluor...
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A high-sensitivity cavity ring-down spectroscopy gas detection system with integrated optical components and embedded microprocessor units is presented for the detection of hydrogen sulfide(H_(2)S)in sulphur hexafluoride(SF_(6))and its mixture with nitrogen(N_(2)).The system exploits a periodic laser wavelength modulation to simplify the mode *** line profile fitting is used for sample quantitative *** verify the sensitivity and stability of concentration detection,the effect of background gas and temperature on the responses of spectral line broadening and absorption cross-section are *** result deviation caused by variation of background gas can be compensated by the pre-correction of empty cavity ring-down *** is also found that the implication of tem-perature on the spectra cannot be *** full width at half maximum and peak value decreased linearly with the increase of temperature,while the baseline is undergoing accelerated *** Allan variance analysis,the limits of detection reach 4.44×10^(-9)in SF_(6)and 2.96×10^(-9)in N_(2)with average time of 67 *** study provides a meaningful approach for the online detection of characteristic gas in gas insulation equipment.
In complex electromagnetic environments, targets that need to be interfered with often possess high levels of concealment and anti-interference capabilities. Additionally, due to the dynamic characteristics of these t...
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Cerebral stroke is a major health problem, and if not recognized and treated immediately, it can result in considerable morbidity and fatality. Predicting the possibility of a stroke can help with intervention, result...
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The advent of the Internet of Things (IoT) has revolutionized connectivity by interconnecting a vast array of devices, underscoring the critical need for robust data security, particularly at the Physical Layer Securi...
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The advent of the Internet of Things (IoT) has revolutionized connectivity by interconnecting a vast array of devices, underscoring the critical need for robust data security, particularly at the Physical Layer Security (PLS). Ensuring data confidentiality and integrity during wireless communications poses a primary challenge in IoT environments. Additionally, within the constrained frequency bands available, Cognitive Radio Networks (CRNs) has emerged as an urgent necessity to optimize spectrum utilization. This technology enables intelligent management of radio frequencies, enhancing network efficiency and adaptability to dynamic environmental changes. In this research, we focus on examining the PLS for the primary channel within the underlying CRNs. Our proposed model involves a primary source-destination pair and a secondary transmitter-receiver pair sharing the same frequency band simultaneously. In the presence of a common eavesdropper, the primary concern lies in securing the primary link communication. The secondary user (SU) acts as cooperative jamming, strategically allocating a portion of its transmission power to transmit artificial interference, thus confusing the eavesdropper and protecting the primary user's (PU) communication. The transmit power of the SU is regulated by the maximum interference power tolerated by the primary network's receiver. To evaluate the effectiveness of our proposed protocol, we develop closed-form mathematical expressions for intercept probability ((Formula presented.)) and outage probability (OP) along the primary communication link. Additionally, we derive mathematical expressions for OP along the secondary communications network. Furthermore, we investigate the impact of transmit power allocation on intercept and outage probabilities across various links. Through both simulation and theoretical analysis, our protocol aims to enhance protection and outage efficiency for the primary link while ensuring appropriate secondary
Global illumination(GI)plays a crucial role in rendering realistic results for virtual exhibitions,such as virtual car *** scenarios usually include all-frequency bidirectional reflectance distribution functions(BRDFs...
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Global illumination(GI)plays a crucial role in rendering realistic results for virtual exhibitions,such as virtual car *** scenarios usually include all-frequency bidirectional reflectance distribution functions(BRDFs),although their geometries and light configurations may be *** allfrequency BRDFs in real time remains challenging due to the complex light *** approaches,including precomputed radiance transfer,light probes,and the most recent path-tracing-based approaches(ReSTIR PT),cannot satisfy both quality and performance requirements ***,we propose a practical hybrid global illumination approach that combines ray tracing and cached GI by caching the incoming radiance with *** approach can produce results close to those of ofline renderers at the cost of only approximately 17 ms at runtime and is robust over all-frequency *** approach is designed for applications involving static lighting and geometries,such as virtual exhibitions.
Bridge decks are the surface of bridges that carry the weight of the vehicles and pedestrians crossing over them. The design of bridge decks varies depending on the span, traffic volume, and material availability. But...
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Concrete is a vital component in modern construction, prized for its strength, durability, and versatility. Accurately determining the quantities of concrete components is crucial in civil engineering applications to ...
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Mangroves are woody plant communities that appear in tropical and subtropical regions,mainly in intertidal zones along the *** their considerable benefits to humans and the surrounding environment,their existence is t...
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Mangroves are woody plant communities that appear in tropical and subtropical regions,mainly in intertidal zones along the *** their considerable benefits to humans and the surrounding environment,their existence is threatened by anthropogenic activities and natural ***,it is vital to conduct efficient efforts to increase mangrove plantations by identifying suitable *** efforts are required to support conservation and plantation practices and lower the mortality rate of ***,identifying ecologically potential areas for plantation practices is mandatory to ensure a higher success *** study aimed to identify suitable locations for mangrove plantations along the southern coastal frontiers of Hormozgan,*** this end,we applied a hybrid Fuzzy-DEMATEL-ANP(FDANP)model as a Multi-Criteria Decision Making(MCDM)approach to determine the relative importance of different criteria,combined with geospatial and remote sensing *** this regard,ten relevant sources of environmental criteria,including meteor-ological,topographical,and geomorphological,were used in the *** statistical evaluation demonstrated the high potential of the developed approach for suitable location *** on the final results,6.10％and 20.80％of the study area were classified as very-high suitable and very-low suitable *** obtained values can elucidate the path for decision-makers and managers for better conservation and plantation ***,the utility of charge-free remote sensing data allows cost-effective implementation of such an approach for other regions by interested researchers and governing organizations.
Recently,significant efforts have been exerted to replace mineral oil with environmentally friendly oils due to safety and environmental ***,there is a need to clarify the physical mechanisms behind the ageing impact ...
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Recently,significant efforts have been exerted to replace mineral oil with environmentally friendly oils due to safety and environmental ***,there is a need to clarify the physical mechanisms behind the ageing impact of these *** authors use advanced optical spectroscopy techniques in correlation with dielectric measurements to understand the ageing processes in environmentally friendly oils as well as mineral ***,different samples of environmentally friendly oils and mineral oil were utilised to investigate the ageing *** samples were subjected to different ageing periods using a thermal accelerated ageing ***,the severity of the produced byproducts due to the oil degradation is examined based on several measured properties representing macroscopic and microscopic *** macroscopic category was evaluated through dielectric properties,including breakdown voltage,dielectric permittivity,and dissipation *** microscopic category,on the other hand,was assessed using techniques such as ultraviolet-visible absorption spectroscopy and photoluminescence *** techniques enabled a deep understanding of the molecular-level changes occurring in the oil under ageing conditions,thereby getting new insights into oil ageing *** is worth mentioning that natural ester oil demonstrated the most favourable performance across various properties under ageing conditions.
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