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The challenging issues in infrared and visible image fusion (IVIF) are extracting and fusing as much useful information as possible contained in the source images, namely, the rich textures in visible images and the significant contrast in infrared images. Existing fusion methods cannot address this problem well due to the handcrafted fusion operations and the extraction of features only from a single scale. In this work, we solve the problems of insufficient information extraction and fusion from another perspective to overcome the difficulties in lacking textures and unhighlighted targets in fused images. We propose a multi-scale feature extraction (MFE) and joint attention fusion (JAF) based end-to-end method using a generative adversarial network (MJ-GAN) framework for the aim of IVIF. The MFE modules are embedded in the two-stream structure-based generator in a densely connected manner to comprehensively extract multi-grained deep features from the source image pairs and reuse them during reconstruction. Moreover, an improved self-attention structure is introduced into the MFEs to enhance the pertinence among multi-grained features. The merging procedure for salient and important features is conducted via the JAF network in a feature recalibration manner, which also produces the fused image in a reasonable manner. Eventually, we can reconstruct a primary fused image with the major infrared radiometric information and a small amount of visible texture information via a single decoder network. The dual discriminator with strong discriminative power can add more texture and contrast information to the final fused image. Extensive experiments on four publicly available datasets show that the proposed method ultimately achieves phenomenal performance in both visual quality and quantitative assessment compared with nine leading algorithms. [ABSTRACT FROM AUTHOR]

The electronic and second‐order nonlinear optical (NLO) properties of small Agn clusters (n = 1 to 3) doped graphyne (GY) and pyrazine‐modified graphyne (pyGY) have been investigated employing (time‐dependent) density functional theory calculations. A large triangular hole of GY provides an efficient site to accommodate the Agn cluster, and an Ag atom prefers to be located in the center of the pyGY, interacting with the two pyridine N atoms. The silver clusters have strong interactions with GY/pyGY, and the intramolecular charge transfer is significant for determining NLO properties. The first hyperpolarizability (β0) values can be modulated by the introduction of silver clusters. The results show that the second‐order NLO response of Ag2/Ag3 doped pyGY complex is stronger than that of corresponding Ag2/Ag3 doped GY complex, while the β0 for single Ag doped GY is significantly higher than that of Ag@pyGY. Hence, the NLO responses of these complexes depend on the size of the clusters and the type of nanosheets. All complexes exhibit excellent transparency in the deep ultraviolet region, especially Ag3@GY/pyGY. These results suggest that these Agn clusters doped GY/pyGY are excellent candidates for potential applications in optical devices. [ABSTRACT FROM AUTHOR]

The electronic and nonlinear optical (NLO) properties of Al13-TCNQ/F4-TCNQ were systematically investigated using density functional theory methods. The Al13-TCNQ/F4-TCNQ complex has a high ionization potential of 7.51/6.71 eV and a strong binding energy of 1.93/2.39 eV, indicating its high structural stability. The stability of the complexes is confirmed through atom-centered density matrix propagation simulation at different temperatures up to 2000 fs. TCNQ/F4-TCNQ (electron donor) interacts with Al13 to form a charge-transfer framework, and F4-TCNQ is a stronger electron acceptor. A113-TCNQ and A113-F4-TCNQ complexes exhibit excellent NLO responses [static first and second hyperpolarizability (β0 and γ0), hyper-Rayleigh scattering coefficient (βHRS), frequency-dependent first hyperpolarizability β(−2ω; ω, ω) and β(−ω; ω, 0)], which are crucial evaluation indexes for designing NLO materials. The static and dynamic hyperpolarizability increases with the enhancement of the electron-acceptor capacity, for example, the β0 value of Al13-F4-TCNQ (92 275 au) is larger than that of Al13-TCNQ (76 720 au). The absorption spectrum reveals that these molecules have deep ultraviolet (UV) and infrared (IR) transparent regions, and hence are new UV and IR NLO molecules. Therefore, linking an Al13 cluster with TCNQ/F4-TCNQ is an effective strategy to design stable potential candidates for high-performance NLO molecules. [ABSTRACT FROM AUTHOR]

Based on the donor‐acceptor framework of graphdiyne–triphenylamine (GDY–TPA), eight GDY–π–TPA molecules were designed by introducing a π‐conjugated bridge, including electron‐rich heterocycles, electron‐deficient heterocycles, and unsaturated hydrocarbons. The geometric structures, electronic characteristics, static nonlinear optical (NLO) properties, and frequency‐dependent HRS first hyperpolarizabilities were investigated employing the density functional theory (DFT) calculations. The charge population analysis reveals that electron‐rich heterocyclics and unsaturated hydrocarbons act as donors, whereas electron‐deficient heterocyclics can be regarded as acceptors, significantly increasing the first hyperpolarizabilities (β0) of GDY–π–TPA (except for B‐3). The C‐1 compound containing the vinyl unit is the best NLO model among all systems. The nature of the excellent NLO properties of the systems can be understood from the low excitation energy of the crucial excited state and the analysis of the first hyperpolarizability density. In addition, the varying order of static and dynamic βHRS values is consistent with those of β0 values. Understanding the relationship between structure and nonlinear optical response can provide guidance for the theoretical design of NLO molecules. [ABSTRACT FROM AUTHOR]

This paper examines the demand for military expenditure in eighteen selected Indo-Pacific countries for the years 1993–2018. As the dominant powers, the U.S. and China characterize the geopolitical structure of the Indo-Pacific region. Sino-U.S. relations are newly quantified by measuring the number of cooperative and conflict events between China and the United States based on the Global Database of Events, Language, and Tone (GDELT). After incorporating Sino-U.S. relation variables into neoclassical demand models, the panel data estimating results reveal that the increasing number of confrontations from the United States toward China has lead to increases in non-U.S. allies' military expenditure while the rise in China confronting the United States has not. U.S. allies in the Indo-Pacific region have tended to increase military expenditure when the United States increases its pressure on China. The empirical results provide evidence that Sino-U.S. relations affect the level of military expenditure in the Indo-Pacific Region. [ABSTRACT FROM AUTHOR]

Abstract Background Since 2008, a progressive pneumonia has become prevalent in broilers and laying hens. This disease occurrs the first day after hatching and lasts more than 30 days, resulting in approximately 70% morbidity and 30% mortality in broilers. The objective of this study was to isolate and identify the pathogens that are responsible for the progressive pneumonia and establish an animal model for drug screening. Results 193 serum samples were collected from 8 intensive farms from 5 provinces in China and analysed in the current research. Our clinical survey showed that 65.2% to 100% of breeding broilers, breeding layers, broilers and laying hens were seropositive for ORT antibodies. From 8 intensive farms, six ORT isolates were identified by PCR and biochemical assays, and two H9N2 viruses were isolated. Newcastle Disease Virus (NDV) and Infectious BronchitisVirus (IBV) were excluded. Typical pneumonia and airsacculitis were observed both in broilers inoculated intraperitoneally with an ORT isolate alone and in those co-infected with ORT and H9N2 virus isolates. Specifically, the survival rate was 30%, 20%, 70%, 50% and 90% in birds inoculated with ORT+H9N2 virus, ORT followed by H9N2 virus, H9N2 virus followed by ORT, and ORT or H9N2 virus alone, respectively. Conclusions The results of this study suggest that ORT infections of domestic poultry have been occurring frequently in China. ORT infection can induce higher economic losses and mortality if H9N2 AIV is also present. Although the isolation of ORT and H9N2 virus has been reported previously, there have been no reported co-infections of poultry with these two pathogens. This is the first report of co-infection of broilers with ORT and H9N2 virus, and this co-infection is probably associated with the outbreak of broiler airsacculitis in China, which has caused extensive economic losses.

Based on the combination of novel carbon material graphynes (GYs) and superalkalis (OM3), a class of GY superalkali complexes, OM3+@(GY/GDY/GTY)− (M = Li, Na, and K), has been designed and investigated using the density functional theory method. Computational results reveal that these complexes with high stability can be regarded as novel superalkali salts of GYs due to electron transfer from OM3 to GYs. For second‐order nonlinear optical response, these superalkali salts exhibit large first hyperpolarizabilities (β0). Two essential effects on β0 values are found, namely, the atomic number of alkali atom in superalkali and the pore size of GY. Integrating the two effects, the selected combination of OLi3 with large pore size graphtrigne (GTY) can lead to a considerable β0 value (6.5 × 105 au), which is a new record for superatom‐doped GYs. In the resulting complex, the OLi3 unit is located at the center of the pore of GTY, forming a planar structure with the highest stability among these salts. Besides large β0 values, these superalkali salts of GYs have a deep‐ultraviolet working region; hence, they can be considered a kind of high‐performance deep‐ultraviolet NLO molecule. [ABSTRACT FROM AUTHOR]