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In this study, a real-time dwell scheduling algorithm based on pulse interleaving is proposed for a distributed radar network system. A time pointer vector is introduced to indicate the moment when the dwell task with the highest synthetic priority should be chosen. This task is further allocated to the radar node with the lowest interleaving time utilization ratio, effectively reducing the time gaps during scheduling. Meanwhile, the pulse interleaving analysis determines whether the assigned dwell task can be scheduled successfully on the corresponding radar node. The time slot occupation matrix and energy assumption matrix are introduced to indicate the time and energy resource consumption of radar nodes, which not only simplifies the pulse interleaving analysis process but also enables pulse interleaving among the tasks with different pulse repetition intervals and numbers. Furthermore, to improve the efficiency of dwell scheduling, a threshold of interleaving time utilization ratio is set to adaptively choose the sliding step of the time pointer. The simulation results reveal that the proposed algorithm can execute real-time dwell scheduling for a distributed radar network system and achieve better scheduling performance than the existing dwell scheduling algorithm.

Abstract The effective dwell scheduling algorithm must be studied to make full use of the radar system's limited resources. In this study, a real‐time dwell scheduling in phased array radar is investigated, where the optimisation problem model that takes the importance, urgency and desired execution time criteria into consideration is built. A real‐time dwell scheduling algorithm for phased array radar based on a backtracking strategy is proposed to solve this problem. Based on the scheduled task pointed by the time pointer, when it is not interleaved with the previously scheduled tasks, two previously interleaved blocks are backtracked, and the actual execution time of tasks in these two blocks are adjusted. In order to guarantee real‐time scheduling, the concept of the virtual dwell task is introduced to reduce the dimension of the original execution time optimisation problem first, then it is converted into two convex optimisation problems and their analytical solutions are deduced. Simulation results demonstrate that the proposed algorithm can realise real‐time dwell scheduling, and it has the lowest Task Drop Ratio, the highest Hit Value Ratio, Time Utilisation Ratio and low Average Time Shifting Ration compared with conventional and up‐to‐date algorithms.

Abstract Background Bone morphogenetic protein 9 (BMP9) has been identified as a crucial inducer of osteoblastic differentiation in mesenchymal stem cells (MSCs). Although microRNAs (miRNAs) are known to play a role in MSC osteogenesis, the mechanisms of action of miRNAs in BMP9-induced osteoblastic differentiation remain poorly understood. Methods In this study, we investigate the possible role of the miR17-92 cluster in the BMP9-induced osteogenic differentiation of MSCs by using both in vitro and in vivo bone formation assays. Results The results show that miR-17, a member of the miR17-92 cluster, significantly impairs BMP9-induced osteogenic differentiation. This impairment is effectively rescued by a miR-17 sponge, an antagomiR sequence against miR-17. Using TargetScan and the 3′-untranslated region luciferase reporter assays, we show that the direct target of miR-17 is the retinoblastoma gene (RB1), a gene that is pivotal to osteoblastic differentiation. We also confirm that RB1 is essential for the miR-17 effects on osteogenesis. Conclusion Our results indicate that miR-17 expression impairs normal osteogenesis by downregulating RB1 expression and significantly inhibiting the function of BMP9.

The effect of different welding heat inputs on the microstructure and mechanical properties of the simulated coarse grained heat affected zone (CGHAZ) of high-strength wind power steel with yield strength of 500 MPa has been investigated using scanning electron microscopy (SEM) and electron backscatter diffraction (EBSD). Charpy impact tests have demonstrated that there exists an optimum heat input of ∼20 kJ/cm that allows optimum impact toughness to be obtained for the CGHAZ. It was shown that this is related to the refined bainitic structure and the highest density of high-angle grain boundaries (HAGBs) with misorientation angle of more than 45°. In crystallographic visualization studies, it was shown that the weakest variant selection occurs for the bainite transformation in the optimal heat input, leading to the highest density of HAGBs with each Closed-packet group containing two or three Bain groups and showing a staggered arrangement structure. The contribution that can effectively deflect and prevent crack propagation during impact experiments has to come from the block boundary. However, it was also found that the center segregation induced by C and Mn reduces the low-temperature impact toughness of the core sample before and after simulated welding, and affects the fluctuations of impact toughness and fatigue performance of simulated CGHAZ. Mn segregation can have a genetic effect on the welding heat affected zone, inducing a lower temperature martensitic transformation, which in turn leads to a decrease in low-temperature toughness and fatigue crack arrest performance.

Metasurfaces provide excellent design flexibility, allowing for the creation of versatile integrated designs with significant potential for practical applications. This paper proposes a dual-channel polarization-modulated metasurface, which realizes the modulation of line-polarized light (LP) to circularly polarized light (CP) with opposite rotation. The polarization state of the dual channels can be changed by adjusting the polarization angle of the line-polarized light. Through the reasonable selection of element atoms, the function of the quarter waveplate is combined with the wavefront control of the general metalens, and the spiral phase can be arbitrarily added to the two channels to realize the simultaneous generation of multi-mode vortex beams. This work achieves functional integration on a single-layer metasurface, enabling its application in polarization imaging and other areas. This work achieves functional integration on a single-layer metasurface, enabling its application in polarization imaging and other areas.

Porcine deltacoronavirus (PDCoV) is an emerging swine enteropathogenic coronavirus (CoV) that mainly causes acute diarrhea/vomiting, dehydration, and mortality in piglets, possessing economic losses and public health concerns. However, there are currently no proven effective antiviral agents against PDCoV. Cepharanthine (CEP) is a naturally occurring alkaloid used as a traditional remedy for radiation-induced symptoms, but its underlying mechanism of CEP against PDCoV has remained elusive. The aim of this study was to investigate the anti-PDCoV effects and mechanisms of CEP in LLC-PK1 cells. The results showed that the antiviral activity of CEP was based on direct action on cells, preventing the virus from attaching to host cells and virus replication. Importantly, Surface Plasmon Resonance (SPR) results showed that CEP has a moderate affinity to PDCoV receptor, porcine aminopeptidase N (pAPN) protein. AutoDock predicted that CEP can form hydrogen bonds with amino acid residues (R740, N783, and R790) in the binding regions of PDCoV and pAPN. In addition, RT-PCR results showed that CEP treatment could significantly reduce the transcription of ZBP1, cytokine (IL-1β and IFN-α) and chemokine genes (CCL-2, CCL-4, CCL-5, CXCL-2, CXCL-8, and CXCL-10) induced by PDCoV. Western blot analysis revealed that CEP could inhibit viral replication by inducing autophagy. In conclusion, our results suggest that the anti-PDCoV activity of CEP is not only relies on competing the virus binding with pAPN, but also affects the proliferation of the virus in vitro by downregulating the excessive immune response caused by the virus and inducing autophagy. CEP emerges as a promising candidate for potential anti-PDCoV therapeutic development.

Abstract The rapid expansion of large-scale pig farming has brought about a surge in viral diseases with high morbidity rates and diverse manifestations. This widespread occurrence of multiple viral diseases in pig farms has inflicted severe economic losses on the global swine industry. Consequently, there is an urgent need for eco-friendly and efficient antiviral drugs that can effectively combat viruses and prevent diseases such as PEDV, PRRSV, PRV, and other viral infections. To this end, we conducted a study on the antiviral activity and cytotoxicity of eleven different Chinese herbal extracts (CHE) against PRV. In vitro testing of several extracts, namely, Echinacea, Ilex purpurea Hassk, Ganoderma lucidum Kars, Taraxacum mongolicum, and Ilex rotunda Thunb, exhibited remarkable inhibition of PRV infection without causing any cytotoxic effects. Specifically, their antiviral selectivity indexes were significantly higher, with values ranging from 6- to 144-fold. The antiviral efficacy of five CHEs was evaluated against other RNA viruses, including PRRSV and PEDV. The extracts showed substantial inhibition of PEDV and PRRSV proliferation. Echinacea and Ilex purpurea Hassk extracts exhibited the highest virus inhibitory effects. To understand the antiviral mechanisms underlying their potent activity, a time-of-addition experiment was conducted. The results indicated that these extracts effectively targeted the early infection and postinfection stages of PRV, PEDV, and PRRSV. The study found that the Chinese herbal extracts, Echinacea and Ilex purpurea Hassk, had both direct and indirect effects on virus particles and cellular targets, demonstrating broad-spectrum antiviral activity against multiple clinical strains of PRV and PEDV. These findings provide a strong foundation for the development of herbal medicines to prevent and treat infections caused by PRV, PEDV and PRRSV in the swine industry. The identified extracts show great promise for the formulation of effective and environmentally friendly antiviral interventions. Graphical Abstract

Metalenses, with their unique modulation of light, are in great demand for many potential applications. As a proof-of-principle demonstration, we focus on designing SiO2 metalenses that operate in the deep ultraviolet region, specifically around 193 nm. Based on the deep ultraviolet metalens proposed in this paper, an integrated deep ultraviolet doublet metalens is further offered. When the incident light is a plane wave with a wavelength of 193 nm, the integrated doublet metalens can reduce the beam size by a factor of 4:1, and the emitted light is flat. The integrated doublet metalens can project the reticle image proportionally, making the projection image clear. The integrated doublet metalens has the best imaging effect at the propagation distance of 2 μm and can tolerate ±3 degrees of incident angle deviation. Our findings establish general and systematic strategies to guide the design of traditional optical lens arrays with excellent integrated doublet metalenses and pave the way for enhanced optical performance in the application of large-relative-aperture deep ultraviolet detection, deep ultraviolet microscope systems, laser beam combining systems, deep ultraviolet lithography systems, etc.

The broadband metamaterial perfect absorbers over various incident angles are highly significant in long-wave infrared (LWIR) detection. Previous research on LWIR metamaterial absorbers has mainly focused on metallic resonators. Here, we propose two broadband LWIR metamaterial absorbers that use dielectric resonators instead. The germanium (Ge) resonators on the top layer excite resonance modes that control the equivalent impedance of the structure, which acts on the high-lossy Si3N4-Ti reflecting layer to assume the absorption. Firstly, we designed a three-layer structure of Ge-Si3N4-Ti, which achieved a broadband absorption with an average absorptivity of 93.1 % in the 8–12 μm range. The absorption ratio of metal can be effectively reduced by replacing the metal. Then, to further enhance the absorptivity, we inserted a Si3N4 layer into the Ge layer, increasing the 90 % absorption bandwidth to 7.96–14.16 μm and the average absorptivity in 8–14 μm to 96.5 %. Compared to metamaterial absorbers based on metallic resonators, dielectric resonators with a large feature size make fabricating easier. Our proposed metamaterial absorber provides ultra-wideband absorption covering the LWIR range. In addition, it is insensitive to the incident angle, making it a potential candidate for thermal imaging and broadband thermal emission applications.

Spatially concentrated absorption is able to form local hotspots and helps to generate hot electrons with higher energy than free electrons, which can be used to improve the performance of hot electron devices. Herein, a broadband, wide‐angle, and highly concentrated metamaterial absorber operating in near‐infrared and midinfrared bands is proposed. The absorptivity of the proposed absorber exceeds 90% in the wavelength range of 2.0–5.4 μm, and the average absorptivity at 2.0–5.4 μm reaches 93.5%. Moreover, the absorber can highly concentrate the energy of the incident light on a point on the bottom surface of the device; the area with concentrated energy only accounts for 1.4% of the total area of the bottom, thus forming a hotspot. Meanwhile, the absorber can still maintain an average absorptivity of more than 85% when the incident light angle of various polarization directions reaches 60°. These characteristics enable the device to provide a solution to improve the performance of hot electrons, energy collection, and imaging devices.

Metamaterial absorbers (MAs) provide new miniaturization, integration, and high‐performance solution for infrared polarization imaging systems. However, it is challenging for past MAs to obtain broadband absorption and a high extinction ratio simultaneously. Herein, a long‐wave infrared broadband polarization‐selective MA with an ultrahigh extinction ratio is proposes and numerically demonstrated. The MA is composed of a metal–dielectric–metal sandwich structure. The cut‐wire resonator on the top layer and the wire pair on the bottom layer provide the MA with excellent polarization selectivity. In the wavelength range of 8.28–14.15 μm, the absorption of the Transverse Magnetic (TM) wave is greater than 90%, while the absorption of the Transverse Electric (TE) wave is less than 0.15%, and the average extinction ratio reaches 724. The high extinction ratio remains to reach 119 when the MA is integrated into a silicon substrate. This work promises to bring new solutions to infrared polarization imaging.

Black silicon properties are investigated in the wavelength range extending from 0.2 to 25 μm with a focus on the mid‐infrared (MIR). It is demonstrated that concurrently increasing the initial level of doping of bare silicon, with given limits, enables reaching even higher absorptance and higher spectral range. Unprecedented light absorptance levels are obtained on black silicon with up to 99.5% in the spectral range from 1 to 8 μm and above 90% until 20 μm, leading to ultrabroadband, ultrablack silicon surfaces. The synergetic effects of morphology and volume doping are elucidated; in particular, how the high aspect‐ratio of conical nanostructures plays a crucial role. The experimental findings are analyzed with numerical simulations involving plasmonic effects of highly doped silicon and supported by tomographic processing of microscopy images. Guidelines and corresponding manufacturing routes are provided by which ultrabroadband, ultrablack silicon surfaces can be obtained within minutes of plasma processing, with no need for further functionalization. With the scalable manufacturing involving solely pure silicon, the resulting ultrabroadband perfect absorbers should be of benefit for large‐scale deployment of radiative cooling devices, blackbody infrared light sources, and infrared radiation sensing.

Two-party collaborative signature scheme is an important cryptographic technology for user authentication and data integrity protection when using mobile devices for financial and securities transactions. However, the two-party collaboration scheme has the following shortcomings: firstly, it is not flexible enough, and it requires the collaborating parties to be secure and trusted; secondly, the two-party collaboration security still needs to be improved. Once a hacker obtains the signature private key and collaborative identity of a mobile device, it can construct a legitimate two-party collaborative signature. Third, the application scenario of two-party co-signature is limited and cannot meet the application scenario of multi-device co-signature. For this reason, this paper designs a multi-party collaborative signature scheme based on SM2 digital signature algorithm in the standard "SM2 Elliptic Curve Public Key Cryptography" of GM/T003-2012. This scheme consists of multiple (more than 2) participants to jointly generate the signature group public key and valid signature in an interactive manner, while ensuring that each user cannot know the signature key other than their own during the signing process. We implement this scheme based on the GMP library. The experimental results show that this scheme is not only flexible but also more secure and trustworthy to meet the application scenario of multi-device collaborative signing. In addition, the time for multiple participants to construct signatures in this scheme is similar, and the time for signature verification is less different from that of the original SM2 signature.

The infrared radiation of the target and scene needs to be transmitted through the surface atmosphere, and it can be detected by infrared thermal imaging equipment. The mid-wave infrared band (MWIR, 3–5 μm) and the long-wave infrared band (LWIR, 8–14 μm) are two atmospheric windows for heat transmission and are the principal operating band of infrared equipment. This paper proposed a broadband metamaterial absorber based on hybrid multi-mode resonance in the MWIR and LWIR. Metamaterial absorber with rectangular grating structure achieves a total of six absorption peaks with high absorption in the MWIR and LWIR. The proposed absorber is scalability in the MWIR and LWIR by tuning the structural parameters. And we designed six absorption peaks to achieve a broadband absorber based on the combined action of propagating surface plasmons (PSP), localized surface plasmons (LSP), and Fabry–Pérot (FP) resonance modes. The average absorption rate of the MWIR is 52 %, and the average absorption rate of the LWIR is 86 %. The geometry of the absorber structure is relatively large, which facilitates fabrication and integration. Although, in terms of its resonance mechanism, the absorption is directly related to the incident angle. However, the metamaterial absorber maintains good wide-angle characteristics when the incident angle is ± 45°. Therefore, the proposed dual-band absorbers in the MWIR and LWIR will have great application potential in infrared detection devices.

Pseudorabies is a highly contagious viral disease caused by the pseudorabies virus (PRV), and it is one of the most devastating diseases for the swine industry worldwide. However, the host-virus interaction and virus-related host factors at the mRNA level in virus natural host (pig) cells, are not fully understood. Here, we performed time-course RNA sequencing of the PK-15 cells infected with a recombinant strain PRV-Becker-GFP to study the dynamic competition between the host and the virus. At early stage of infection (3 hpi), our results suggested that the activation of cytosolic DNA-sensing pathway and NOD-like receptor signaling pathway might play a role in recognition of PRV, and the activation of NF-kappa B signaling pathway and TNF signaling pathway might be involved in immune response against the virus. However, all these pathways were subsequently inhibited by PRV. Additionally, our data indicated the fatty acid degradation pathway was significantly downregulated during late stage of infection (9 hpi), which was likely to accumulate fatty acids for viral envelope synthesis. Moreover, we verified the expression of 5 representative genes (ALDH1B1, ACAA2, ACSL3, ADH5, and EHHADH) related to fatty acid degradation pathway by RT-qPCR. Overall, our findings provide valuable information to better understand host-virus interactions and the immune escape mechanism of PRV-Becker as a virulent strain, offering novel targets for porcine anti-PRV breeding research and potential clinical treatment.

We provide a method to regulate intramolecular charge transfer (ICT) through distorting fragment dipole moments based on molecular planarity and intuitively investigate the physical mechanisms of one-photon absorption (OPA), two-photon absorption (TPA), and electron circular dichroism (ECD) properties of the multichain 1,3,5 triazine derivatives o-Br-TRZ, m-Br-TRZ, and p-Br-TRZ containing three bromobiphenyl units. As the position of the C–Br bond on the branch chain becomes farther away, the molecular planarity is weakened, with the position of charge transfer (CT) on the branch chain of bromobiphenyl changing. The excitation energy of the excited states decreases, which leads to the redshift of the OPA spectrum of 1,3,5-triazine derivatives. The decrease in molecular plane results in a change in the magnitude and direction of the molecular dipole moment on the bromobiphenyl branch chain, which weakens the intramolecular electrostatic interaction of bromobiphenyl branch chain 1,3,5-triazine derivatives and weakens the charge transfer excitation of the second step transition in TPA, leading to an increase in the enhanced absorption cross-section. Furthermore, molecular planarity can also induce and regulate chiral optical activity through changing the direction of the transition magnetic dipole moment. Our visualization method helps to reveal the physical mechanism of TPA cross-sections generated via third-order nonlinear optical materials in photoinduced CT, which is of great significance for the design of large TPA molecules.

Ultra-broadband metamaterials absorbers with high absorption, ultrathin thickness and easy configurations are designed and demonstrated, which pave the way for enhancing the optical performance in applications of infrared thermal emitters, imaging and photodetectors.

Herein, a hierarchical metamaterial (HMM) is reported to achieve multispectral camouflage for thermal infrared detectors and radar. The HMM consists of a frequency‐selective emitter (FSE) integrated with a microwave absorber (MA). The FSE layer has an average absorptivity of 0.18, 0.85, and 0.18 in the wavelength of 3–5, 5–8, and 8–14 μm, respectively, in the case of the normal incidence. The absorptivity of MA maintains more than 91% (87%) in the broadband of 8–12 GHz (the entire X‐band) up to incident angles of ±40° for TM (TE) polarization. Overall, the average surface emissivity of HMM is 0.25, 0.86, and 0.26 in the infrared broadband of 3–5, 5–8, and 8–14 μm, respectively. The FSE considers infrared camouflage and infrared radiative cooling. The performance of HMM in microwave range remains unchanged, compared to MA structure without FSE layer. From the point of view of thickness, the HMM structure is only 2.34 mm. These excellent performances indicate that the herein described proposed HMM has promising applications in multispectral camouflage fields.

Beam splitters are widely applied in various optical systems as a common beam-splitting device. The conventional stereoscopic and flat-type beam splitters greatly limit the packaging and integration of optical systems due to their large size and restricted emitting direction. Recently, beam-splitting devices made of various transmissive or reflective metasurfaces have shown the potential to overcome these challenges. However, in optical systems such as machine vision, these single-ended beam splitters increase the design complexity of the signal feedback link due to the limitation of the beam-splitting path direction. Here, we proposed and numerically simulated a transflective all-dielectric metasurface beam splitter by applying incompletely transmissive structural designs to the metasurface and using the transmission phase modulation mechanism. It can realize the beam separation for arbitrarily polarized incident light on the same side of the normal at both transmissive and reflective ends with a single-layer unit cell arrangement structure and has a similar emergence angle. The results reveal that at 1550 nm, the angular tolerance bandwidth is about 32°, the total splitting efficiency is over 90%, and the splitting ratio is approximately 1:1. After comparison and verification of simulation results, this transflective metasurface beam splitter is hopeful to be applied in new compact optical systems that require real-time signal feedback, such as coaxial light sources and photoelectric sensing.

The introduction of distortions into the metasurfaces with in-plane symmetry offers a possibility to achieve resonances with high quality (Q) factors, but such distortions make the metasurfaces sensitive to the polarization state of the incident light. Here, we propose and numerically demonstrate a polarization-insensitive dual-band refractive index (RI) sensor. In this work, the proposed metasurface is imparted with fourfold symmetry by combining two pairs of asymmetric silicon elliptical nanodisks, allowing it to acquire polarization-insensitive properties to the incident light. Two narrow-band reflection peaks with full width at half maximum (FWHM) of 3.36 nm and 4.53 nm are excited and tailored for RI sensing. Their sensitivities are 2756.67 nm/RIU and 2319.93 nm/RIU, with figure of merit (FOM) values of 820.44 RIU−1 and 532.09 RIU−1. This work provides a new approach to realize polarization-independent and high-performance RI sensor devices.

We design and numerically analyze a Fano resonance device based on periodical all-dielectric “lucky knot” shaped nanostructure in the mid-infrared region with high sensitivity, which is insensitive to polarization and incident angle. The proposed nanostructure is sensitive to the change of the refractive index of the substance to be tested. We established the correspondence between the change of the refractive index and the peak position of the reflection spectrum. And then we propose an optical refractive index sensor with a sensitivity of 986 nm/RIU, and a maximum figure of merit of 32.7, which is much higher compared to the sensor based on metallic materials. The maximum Q-factor can reach 520. This study may provide a further step in optical sensing, biosensing and environmental monitoring.

Infrared broadband absorbers are in great demand in various applications, such as integration into uncooled infrared detectors and microbolometers. In this thesis, we demonstrate and compare three different design methods: coupling multi-sized resonators, inlaying metallic structures in the dielectric layer and choosing laminated dielectric layers made of lossless and lossy materials. Due to their absorption mechanisms, we initially propose a W/ZnTe/W/Ge/W and an embedded Ti/Si/Ti absorber, both of which can achieve ultra-broadband absorption from 8 to 14 μm, with average absorptions of 88% and 92%. We further propose a Ti/Ge/Si3N4/Ti absorbers which can realise near-perfect absorption in the LWIR band, with average absorptions of 95% where all absorption curves exceed 90%. Our study provides the broadband LWIR absorbing structures in addition to providing new insight into the understanding of the interaction of propagating and localised surface plasmon resonances, with the prospect of expanding to other absorbing-structure designs from visible to THz regimes.

Not satisfied with the current stage of the extensive research on 3D printing technology for polymers and metals, researchers are searching for more innovative 3D printing technologies for glass fabrication in what has become the latest trend of interest. The traditional glass manufacturing process requires complex high-temperature melting and casting processes, which presents a great challenge to the fabrication of arbitrarily complex glass devices. The emergence of 3D printing technology provides a good solution. This paper reviews the recent advances in glass 3D printing, describes the history and development of related technologies, and lists popular applications of 3D printing for glass preparation. This review compares the advantages and disadvantages of various processing methods, summarizes the problems encountered in the process of technology application, and proposes the corresponding solutions to select the most appropriate preparation method in practical applications. The application of additive manufacturing in glass fabrication is in its infancy but has great potential. Based on this view, the methods for glass preparation with 3D printing technology are expected to achieve both high-speed and high-precision fabrication.

Abstract Efficiently exciting surface plasmon polaritons (SPP) is highly desired in many photonic applications, but most approaches (such as prism and grating couplers) cannot control flexibly their SPP excitation directions. While Pancharatnam-Berry (PB) metasurfaces were recently proposed to achieve direction-controllable SPP excitations, such scheme suffers from low-efficiency issue due to both direct reflections at the coupler surface and the mode mismatch between the coupler and the guiding-out plasmonic structure. In this article, we solve these issues via imposing two criterions to guide design both the metasurface and the plasmonic metal, based on which a direction-controllable SPP excitation with very high efficiency can be realized. As a proof of concept, we designed/fabricated a realistic device working in the microwave regime, and performed both near-field and far-field measurements to demonstrate that it can achieve an spoof SPP conversion efficiency ~78%, much higher than previous devices. Full-wave simulations are in good agreement with experiments, showing that the efficiency can be further pushed to 92% with optimized designs. Our findings can stimulate spoof SPP-related applications, particularly can help enhance the spin-dependent light-matter interactions in low frequency regime.

Subdirect decomposition of algebra is one of its quite general and important constructions. In this paper, some subdirect decompositions (including subdirect irreducible decompositions) of finite distributive lattices and finite chains are studied, and some general results are obtained.

A strategy for fabricating bendable AlGaInP light emitting diode (LED) arrays is presented in this paper. Sample LED arrays with 8 × 8 pixels were fabricated and subjected to bending. Bending only weakly affected the light output power and the current–voltage characteristics of the arrays. LED arrays suffer from a thermal problem owing to the energy loss during the electrical-to-optical energy conversion. We have designed a three-dimensional heat conduction model for analyzing the effect of the polymer substrate, the configuration of pixels, and the micro-structure on heat dissipation in bendable LED arrays. Thermal conductivity of the polymer substrate critically affected the heat dissipation, suggesting that the substrate thickness should be in the 500–1000 μm range. A larger pixel distance yielded more distributed heat sources and more uniform temperature distribution. Micro-structured polymer substrates yielded lower temperature, especially for the fins array micro-structure. Based on enhancing the polymer’s thermal conductivity and distributing LED pixels, optimizing the substrate’s micro-structure is an effective method to improve heat dissipation in bendable LED arrays. Optimized heat dissipation could effectively reduce heat accumulation in LED arrays and alleviate an increase in the junction temperature, allowing to increase the output power of the device.

An array of 320 × 240 micro-light-emitting diodes (micro-LEDs) based on an AlGaInP epitaxial wafer and with a unit size of 100 µm×100 µm was designed and fabricated. The optimum width of the isolation groove between adjacent light-emitting units was determined based on a compromise between full isolation of each LED and maximization of the light emitting area, and was found to be 20 µm. The grooves were filled with a mixed Si granule-polyurethane composite medium, because this type of insulating material can reflect part of the emitted light from the sidewall to the window layer in each light-emitting unit, and could thus improve lighting output efficiency. The 10-µm-wide square-circle anode was designed to increase the light emitting area while simultaneously being simple to fabricate. The device current used was in the 0.42–1.06 mA range to guarantee internal quantum efficiency of more than 85%, with a corresponding voltage range of 2–2.3 V. The layered temperature distribution in a single unit was simulated under a drive voltage of 2.2 V, and the maximum device temperature was 341 K. The micro-opto-electro-mechanical systems (MOEMS) technology-based fabrication process, experimental images of the device and device test results are presented here.