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Model Order Reduction (MOR) techniques have extensive applications across scientific and engineering disciplines, such as neutron field reconstruction of nuclear reactor cores, thermoelastic field reconstruction, fluid, and solid mechanics. In the process of building a Reduced Order Model (ROM), the selection of the basis functions in the offline stage is crucial and directly depends on the parameter space sampling strategy. This problem has always been a challenge in MOR. Research into adaptive sampling algorithms has become a hot topic in recent years. To better understand the application of these algorithms to MOR, this paper focuses on three prevalent adaptive sampling algorithms: pseudo-gradient sampling, adaptive sparse grid sampling, adaptive training set extension. These have been successfully applied in various applications, including nuclear reactor cores, molten salt reactor system, power system for convection problems. We systematically assess and compare their performance, finding that adaptive sampling algorithms excel in sampling divergent and oscillating areas and are generally better than the standard sampling strategy. Specifically, the pseudo-gradient sampling algorithm is effective for small-scale scenarios, while the other two algorithms are designed for large-scale sampling. Their practicality is confirmed through successful applications in nuclear reactor cores.

Abstract Robust anti‐counterfeiting techniques aim for easy identification while remaining difficult to forge, especially for high‐value items such as currency and passports. However, many existing anti‐counterfeiting techniques rely on deterministic processes, resulting in loopholes for duplication and counterfeiting. Therefore, achieving high‐level encryption and easy authentication through conventional anti‐counterfeiting techniques has remained a significant challenge. To address this, this work proposes a solution that combined fluorescence and structural colors, creating a physically unclonable multiplex encryption system (PUMES). In this study, the physicochemical properties of colloidal photonic inks are systematically adjusted to construct a comprehensive printing phase diagram, revealing the printable region. Furthermore, the brightness and color saturation of inkjet‐printed colloidal photonic crystal structural colors are optimized by controlling the substrate's hydrophobicity, printed droplet volume, and the addition of noble metals. Finally, fluorescence is incorporated to build PUMES, including macroscopic fluorescence and structural color patterns, as well as microscopic physically unclonable fluorescence patterns. The PUMES with intrinsic randomness and high encoding capacity are authenticated by a deep learning algorithm, which proved to be reliable and efficient under various observation conditions. This approach can provide easy identification and formidable resistance against counterfeiting, making it highly promising for the next‐generation anti‐counterfeiting of currency and passports.

This study examines the flow behavior and deformation mechanism of a FGH4113A superalloy with high γ′ content for different strain rates (0.01–1 s−1) at sub-solvus (1030, 1080 °C), near-solvus (1130 °C), and sup-solvus temperatures (1180 °C). The results indicated that the alloy exhibits four different flow behaviors: rapid softening after reaching peak stress (at 1030–1080 °C), slow softening after reaching peak stress (at 1130–1180 °C/0.1–1 s−1), steady state flow (at 1130 °C/0.01 s−1), and continuous hardening (at 1180 °C/0.01 s−1). The strain rate sensitivity exponent decreases as the flow behavior transforms from dynamic softening to continuous hardening. Moreover, the dynamic recrystallization (DRX) fraction decreases with increasing strain rate at sub-solvus temperatures, where an inverse trend was observed at near- or sup-solvus temperatures. These observations are influenced by the interplay of continuous original grain boundary migration (COBM), DRX, and grain growth. Meanwhile, the primary γ′ phase has different roles under distinct deformation conditions. At sub-solvus temperature, the primary γ′ phase facilitates DRX, grain refinement, and coordinated plastic deformation. At near-solve temperature, the primary γ′ phase predominantly contributes to coordinated plastic deformation. At the sup-solvus temperature, the γ′ phase entirely dissolves, with the grains coarsened by COBM continuously undergoing compressed, exhibiting continuous hardening.

Low-temperature bonding of nanotwinned (NT-) metals holds great potential for enhancing the performance and reliability of electronic interconnections. In this study, we performed low-temperature bonding of (111)-oriented nanotwinned silver (NT-Ag) films and thoroughly investigated the influence of (111) texture on the interfacial microstructure and bonding strength of the joints. The results demonstrated that high-quality bonding of highly (111)-oriented NT-Ag films was achieved even at 200 °C in air. The defect-free, coherent Ag(111)Ag(111) bonding interface was formed via face-to-face bonding of the highly (111)-oriented columnar grains. The shear strength of the joints significantly increased with the rise in (111) texture intensity. Moreover, we developed the void closure model to quantitatively elucidate the contribution of (111) texture to void closure and bonding ratio. Modeling results revealed that the (111) texture, with the highest surface diffusion coefficient, greatly increased the interfacial bonding ratio by accelerating surface source diffusion, thereby enabling high-strength bonding at low temperatures. The experimental validation and modeling results presented here contribute a novel perspective for optimizing interfacial microstructure and bonding strength by regulating the surface texture in the solid-state bonding of metals.

Ultrasound-assisted Kovar/SnSb10 assemblies are promising candidates for high-precision electronic devices; however, limited research has been conducted on the effect of ultrasonication on its interfacial evolution and mechanical properties. In this study, the microstructure evolution, orientation relationships (ORs), interinhibitive dissolution-precipitation mechanism, and mechanical properties of a Kovar/SnSb10 assembly with/without ultrasonication were systematically investigated. The morphology of the intermetallics (IMCs) evolved from a newly-formed, lash-type to a block-type morphology with an increasing reflow duration, and dentation-type IMCs appeared after ultrasonication. The interfacial IMC without ultrasonication mainly contained FeSn2 and a minority of Ni3Sn2, whereas the strong disturbance caused by ultrasound led to the formation of FeSn in the peripheral FeSn3 and NiSn IMCs. Furthermore, high-resolution transmission electron microscopy (HRTEM) analysis revealed that the ORs of IMC/solder and IMC/Kovar transformed from coherent and semi-coherent to incoherent relationships after ultrasonic treatment. The ORs of the IMC/solder growth front after ultrasonication were [0 1¯ 1]Sn∥[1 1 0]FeSn3, (0 1 1)Sn∥(0 0 1¯)FeSn3 and [0 1¯ 1]Sn∥[5¯ 1 0]NiSn, (0 1 1)Sn∥(0 1¯ 0)NiSn. Additionally, 60 s ultrasonic treatment promoted the growth of IMCs, and increased the ultimate shear strength by approximately 20 MPa, despite the emergence of incoherent interfaces. This phenomenon was primarily attributed to the dispersion strengthening effect of the abundant ultrasound-induced nano-Ni3Sn2 precipitates. This study substantiates the feasibility of ultrasonication-assisted Kovar/SnSb10 assemblies and introduces a novel concept for low-cost, high-efficiency, and high-performance packaging.

Flexible electronics have attracted increasing attention and are extensively used in medical care and health monitoring applications. However, research on their applications in low-temperature environments is limited, mainly owing to material intrinsic limitation. In this work, a cryogenic pressure sensor using low-melting (−71 °C) ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM]BF4) is fabricated via the template removal method. The sensor unit can function at temperatures ranging from −50 to 30 °C, with improved sensing performance at lower temperatures. At −50 °C, it demonstrates an ultralow detection limit of 0.5 Pa and a high sensitivity of 2.0 × 105 Ω/kPa, thereby enabling the detection of dynamic pressure loads with different frequencies (0.2 to 2 Hz) and waveforms (sine and triangle). Subsequently, these units are integrated into a 3 × 3 array and embedded into a bionic thumb. The sensor can accurately identify up to 9 independent touch points and recognize dynamic sliding with velocities in the range of 0.31 to 4.42 cm/s at an extremely low temperature (−50 °C), thus demonstrating remarkable multitouch and sliding trajectory recognition capabilities. Furthermore, the proposed sensor unit is expected to contribute to the research on the human–machine interface of space suits.

Substantial shear deformation induced by high-frequency friction at the interface is inseparable from recrystallization and welding quality during ultrasonic welding. In this study, we prepared welding surfaces with various micro-asperity scales to analyze the comprehensive effects of deformation heat, shear strain and strain rate on the recrystallization and welding quality. Smaller surface-contacted micro-asperities with a size of 16.03 nm led to a surge in the low angle grain boundaries and recrystallization grains before the formation of a complete weld, which drastically increased the load carry capacity by 139% for joints welded at 1500 J comparing with larger micro-asperities. Molecular dynamics simulation indicated that weld formation involved a dynamic process, including micro-connection, tear, fracture, flattening and weld spread, and the reduction in the micro-asperity scale accelerated the flattening process and aggravated shear deformation at the intimate contact positions. According to the calculation model of recrystallization induced by the shear deformation, smaller micro-asperities promoted the coupling between high shear strain and low strain rate, and maximum shear strain of 1.57 and minimum average strain rate of 346/s were obtained simultaneously, which decreased critical recrystallization strain and enlarged the dynamic recrystallization regions during ultrasonic welding.

Fluorescent materials are used broadly for anti‐counterfeiting, including currency, passports, identity cards, and other secure documents. However, a universal procedure to print fluorescent materials is still missing due to the wide variety of properties found in fluorescent materials. Here, flash nanoprecipitation (FNP) is reported as a universal procedure for fast‐fabricating large‐scale fluorescent nanoparticles to construct cutting‐edge‐level encryption in anti‐counterfeiting, such as full‐color and dual‐mode “codes‐in‐code” large‐format fluorescent patterns. The large‐format fluorescent patterns are printed with a commercial inkjet printer. They exhibitd high concealment and environmental durability for daily use. The security labels of the 2021 Chinese Racing Pigeon Association (CRPA) certificate are then industrially fabricated based on this universal procedure. The monochrome fluorescent pattern is also upgraded into a full‐color fluorescent pattern for evolutionary encryption and anti‐counterfeiting. Finally, a “codes‐in‐code” dual‐mode encryption is realized in the UV bands. The results lead to cutting‐edge and high‐security anti‐counterfeiting technology, which will broaden the use of fluorescent materials in anti‐counterfeiting due to its universality.

Conjugated polymers (CPs) are an active research area and have been commonly used in optoelectronic devices, anticounterfeiting, bioimaging, and drug delivery due to their outstanding properties, such as a high quantum yield, photothermal stability, tunable spectra, and good biocompatibility. However, there have only been a few reports regarding flexible lighting due to the insoluble conjugated structure of CPs. Herein, a facile microemulsion method is used to solve the insolubility issue and fabricate CP nanoparticles for flexible lighting and microdeformation monitoring via high‐resolution inkjet printing. These CP nanoparticles are tuned to emit white light (color coordinates are (0.35, 0.35), and the correlated color temperature is 4810 K) by adjusting the CP ratios and polystyrene content. A CP‐based white light‐emitting diode (WLED) with a high color‐rendering index (up to 95) can be fabricated by coating these nanoparticles onto an ultraviolet light‐emitting diode (UVLED). At a driving current of 30 mA, the luminous efficacy of this WLED is 64 lm W−1 for at least 100 h. The resolution of the printing array is ≈40 μm (635 dots in−1), which can be used to detect 2 μm irreversible microdeformation. This approach may broaden the applications of CPs for flexible lighting and microdeformation monitoring.

Flexible electronics can be seamlessly attached to human skin and used for various purposes, such as pulse monitoring, pressure measurement, tensile sensing, and motion detection. Despite their broad applications, most flexible electronics do not possess both high sensitivity and wide detection range simultaneously; their sensitivity drops rapidly when they are subjected to even just medium pressure. In this study, ultrabroad-range, high-sensitivity flexible electronics are fabricated through additive manufacturing to address this issue. The key to possess high sensitivity and a wide detection range simultaneously is to fabricate flexible electronics with large depth-width ratio circuit channels using the additive manufacturing inner-rinsing template method. These electronics exhibit an unprecedented high sensitivity of 320 kPa−1 over the whole detection range, which ranges from 0.3 to 30,000 Pa (five orders of magnitude). Their minimum detectable weight is 0.02 g (the weight of a fly), which is comparable with human skin. They can stretch to over 500% strain without breaking and show no tensile fatigue after 1000 repetitions of stretching to 100% strain. A highly sensitive and flexible electronic epidermal pulse monitor is fabricated to detect multiple physiological signals, such as pulse signal, breathing rhythm, and real-time beat-to-beat cuffless blood pressure. All of these signals can be obtained simultaneously for detailed health detection and monitoring. The fabrication method does not involve complex expensive equipment or complicated operational processes, so it is especially suitable for the fabrication of large-area, complex flexible electronics. We believe this approach will pave the way for the application of flexible electronics in biomedical detection and health monitoring.

Graphene has been considered as an excellent biochemical sensors’ substrate material because of its excellent physical and chemical properties. Most of these sensors have employed enzymes, antibodies, antigens, and other biomolecules with corresponding recognition ability as recognition elements, to convert chemical signals into electrical signals. However, oxidoreductase enzymes that grow on graphene surfaces are affected significantly by the environment and are easily inactivated, which hinders the further improvement of detection sensitivity and robusticity. A gold-boosted graphene sensor was fabricated by the in situ electrochemical deposition of inorganic gold nanoparticles on vertical graphene nanosheets. This approach solves the instability of biological enzymes and improves the detection performance of graphene-based sensors. The uric acid sensitivity of the gold-boosted electrode was 6230 µA mM−1 cm−2, which is 6 times higher than the original graphene electrode. A 7 h GNSs/CC electrode showed an impressive detection performance for ascorbic acid, dopamine, and uric acid, simultaneously. Moreover, it exhibited a reliable detection performance in human serum in terms of uric acid. The possible reason could be that the vertical aliened graphene nanosheet acts as a reaction active spot. This 3D graphene-nanosheet-based doping approach can be applied to a wide variety of inorganic catalytic materials to enhance their performance and improve their durability in aspects such as single-atom catalysis and integration of multiple catalytic properties.

For binary element atomization, it is essential to investigate the phase transformation from liquid to solid as a functions of the droplet sizes, as well as the reaction competitiveness, during gas atomizing solidification of their nuclei. In the present work, a series of phase transformations of undercooled Cu (60.9 wt.%)/Sn droplets were analyzed when atomized by pressure gas. The results indicated that the microstructures of the obtained powders and their morphologies were highly relevant to the droplet size. According to the phase characteristics analyzed by the microstructural observations in combination with the transient nucleation theory, powders with sizes from 10 to 100 μm were divided into three categories, exhibiting lotus-leaf, island, and stripe morphologies. The competitive formation of Cu6Sn5 or Cu3Sn was also controlled by the droplet sizes, and a diameter of approximately 45 μm was identified as the threshold size. After heat treatment at 300 °C for 4 h, the powders consisted of a single η’ Cu6Sn5 phase. The obtained Cu6Sn5 phase powders can be used in the field of high-temperature applications as intermetallic balls for integrated chip interconnects.

Although absorptive capacity and desorptive capacity has been widely present in university-industry relationships, there has been no research on their potential impact on the relationship between university patent output and university patent transfer network. We constructed datasets of patent applications and patent transfers to firms from 383 universities between 2002 and 2021 in China, and empirically demonstrated the effect of the patent output on university patent transfer network using negative binomial regression models. We also examined the moderating effects of absorptive capacity and desorptive capacity. The results reveal that university patent output positively affects the size and the connection strength of the university patent transfer network. Technology transfer offices and satellite institutions, for desorptive capacity in universities, negatively moderate the relationship between the university patent output and the university patent transfer network, respectively. For absorptive capacity in firms, research and development intensity of new products and the level of research and development personnel input, respectively, have a positively moderate effect on the relationship between the university patent output and the university patent transfer network. Our research provides insights into the dynamics of the university patent transfer network; especially against the backdrop of a sharp increase in university patent output and insufficient development of the university patent transfer network, this study provides evidence to the substitution effect of desorptive capacity in universities and the bidirectional effect of absorptive capacity in firms.

Desert steppe is widely distributed in wind erosion regions, and is also an important potential dust emission source in the regions. Recognition of dust emission characteristics of desert steppe is the foundation for accurate simulation of dust emission in wind erosion regions; however, few related studies have been conducted in desert steppe areas. In this study, we selected four sites in a region of desert steppe to conducting dust emission observations, analyzing the characteristics of horizontal saltation flux and vertical dust flux, identifying the suitable models for desert steppe, and examining the relationship between saltation bombardment efficiency and wind friction speed (u*). The results revealed the following: the supply of saltation particles in most desert steppe is unlimited, the intensity of saltation is reasonably high, and the modified Owen-type model is suitable for predicting sediment transport above desert steppe. Dust emission intensity in desert steppe is lower than that in other land use types under similar wind speeds. Schemes based on saltation bombardment theory (i.e., the MB95, Shao93, and Kok12 schemes) were found suitable for predicting vertical dust flux above desert steppe, the Kok12 dust emission scheme performed slightly better than the other two schemes. Saltation bombardment is the main mechanism for dust emission when u*s exceeds a threshold u*s (u*ts), but aerodynamic entrainment also plays an important role in dust emission, especially when u*s

In this paper, the No. 30201 working face of a specific colliery was determined as the study area in the Yushen mining area, China. The objective of this paper is to determine the optimal position for pressure regulation measures during the final mining stage. A mechanical calculation model for stabilized coal pillar was developed. The analytical solution for the front abutment pressure function was obtained. Limit equilibrium theory and beam theory were employed to compute the critical width value of the stabilized coal pillar. The analysis focused on examining the spatiotemporal relationship between the rotational deformation of the main roof and the stability of the retracement channel. The study utilized numerical simulation to investigate the failure characteristics of the surrounding rock and the stress redistribution in the stabilized coal pillar within the working face. Through comprehensive analysis, a reasonable width of 15 m for the stabilized coal pillar was determined and successfully implemented in field practices. A method of using Artificial Neural Network (ANN) to select the stabilized coal pillar width was proposed. The input characteristics of ANN were determined through theoretical analysis. Four models of BP, WOA-BP, PSO-BP, and CPSO-BP were trained. The calculation accuracy of each model is evaluated by three quantitative metrics: MAE, MRE, and RMSE. The MAE value of the CPSO-BP model is 0.9489, showing a reduction of 70.87% compared to the BP model, 55.84% compared to the WOA-BP model, and 51.26% compared to the PSO-BP model. The MRE value is 0.0559, which is 71.51%, 56.29%, and 53.24% lower than the other models, respectively. The RMSE value is 1.0617, which is 68.92%, 56.13%, and 53.03% lower than other models, respectively. The four models were employed to compute the width of the stabilized coal pillar. The values for the BP, WOA-BP, PSO-BP, and CPSO-BP models were 12.7 m, 16.3 m, 14.1 m, and 15.2 m, respectively, indicating that the CPSO-BP model can effectively determine the width of the stabilized coal pillar.

BackgroundsType 2 Diabetes Mellitus (T2DM) has become a significant global public health issue, characterized by a rising prevalence and associated deficits across multiple organ systems. Our study aims to utilize the DTI-ALPS technique to assess the change of ALPS index in T2DM patients, and to explore whether such changes are correlated with cognition level and diffusion parameters.MethodsThe study involved 41 patients with T2DM (mean age, 60.49 ± 8.88 years) and 27 healthy controls (mean age, 58.00 ± 7.63 years). All subjects underwent MRI examination, cognitive assessment, and laboratory tests. Tract-based spatial statistics (TBSS) was used to evaluate white matter changes. GLM was performed to check the DTI-ALPS index difference between T2DM and HC groups. Spearman correlation analysis and partial correlation analysis were used to analyze the correlation between the DTI-ALPS index and diffusion properties & cognitive scores.ResultsThe results show that the ALPS index was lower in T2DM patients. MoCA score was significantly correlated with the ALPS index. Patients with T2DM had a significant increase in both mean diffusivity (MD) and radial diffusivity (RD) and decrease in fractional anisotropy (FA) compared to the HC group.ConclusionThe results suggest that the ALPS index is decreased in T2DM patients and associates with cognitive level.