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Spectral sensing plays a crucial part in imaging technologies, optical communication, and other fields. However, complicated optical elements, such as prisms, interferometric filters, and diffraction grating, are required for commercial multispectral detectors, which hampers their advance toward miniaturization and integration. In recent years, metal halide perovskites have been emerging for optical‐component‐free wavelength‐selective photodetectors (PDs) because of their continuously tunable bandgap, fascinating optoelectronic properties, and simple preparation processes. In this review, recent advances in wavelength‐selective perovskite PDs, including narrowband PDs, dual‐band PDs, multispectral‐recognizable PDs, and X‐ray PDs, are highlighted, with an emphasis on device structure designs, working mechanisms, and optoelectronic performances. Meanwhile, the applications of wavelength‐selective PDs in image sensing for single‐/dual‐color imaging, full‐color imaging, and X‐ray imaging are introduced. Finally, the remaining challenges and perspectives in this emerging field are presented. [ABSTRACT FROM AUTHOR]

The classical geometry of the 6-endotransition state for nucleophilic additions into oxocarbenium ions can be perturbed by incorporating the reactive groups into medium-sized rings, leading to the formation of 2,6-trans-dialkyl tetrahydropyrans. The bicyclic products exhibit inside–outside stereoisomerism, as seen in numerous macrolide natural products. [ABSTRACT FROM AUTHOR]

• Curved image sensor arrays possess the advantage of the wide field of view, low aberration, simple lens requirement. • The fabrication strategies for curved image sensor arrays are summarized. • The recent advance in curved image sensor array and its application in the artificial electronic eyes are focused. [Display omitted] A conventional wide-angle camera consists of a planar image sensor array and multiple optic elements, which increases the camera's volume, weight, and cost. In nature, most biological visual systems possess a curved retina, providing the capability of a wide field of view imaging with high sensitivity through a single lens. Inspired by the unique advantage of the biological eye, various curved image sensor arrays have been demonstrated, which enable a wide field of view, low aberration, and highly sensitive image acquisition with a simple lens design. Herein, various fabrication strategies for the curved image sensor arrays are summarized. In addition, the applications of the curved device in the artificial electronic eyes as well as the challenges and opportunities of the curved image sensor array are also discussed. [ABSTRACT FROM AUTHOR]

African swine fever virus (ASFV) is the causative agent of African swine fever (ASF) which reaches up to 100% case fatality in domestic pigs and wild boar and causes significant economic losses in the swine industry. Lack of knowledge of the function of ASFV genes is a serious impediment to the development of the safe and effective vaccine. Herein, I267L was identified as a relative conserved gene and an early expressed gene. A recombinant virus (SY18ΔI267L) with I267L gene deletion was produced by replacing I267L of the virulent ASFV SY18 with enhanced green fluorescent protein (EGFP) cassette. The replication kinetics of SY18ΔI267L is similar to that of the parental isolate in vitro. Moreover, the doses of 102.0 TCID50 (n = 5) and 105.0 TCID50 (n = 5) SY18ΔI267L caused virulent phenotype, severe clinical signs, viremia, high viral load, and mortality in domestic pigs inoculated intramuscularly as the virulent parental virus strain. Therefore, the deletion of I267L does not affect the replication or the virulence of ASFV. Utilizing the fluorescent-tagged virulence deletant can be easy to gain a visual result in related research such as the inactivation effect of some drugs, disinfectants, extracts, etc. on ASFV. [ABSTRACT FROM AUTHOR]

Hydropower dams are subjected to soft water penetration during their service lives. Concrete deterioration due to calcium leaching will decrease the durability of concrete and affect dam safety. The long-term performance of concrete dams due to calcium leaching should be evaluated and predicted accurately to complete reinforcement work in a timely manner. In this paper, a methodology that combined microscopic tests and numerical analysis to evaluate the long-term performance of dam concrete due to calcium leaching is proposed. The current state of concrete is evaluated by analyzing the components of sediments and seepage water through microscopic and spectroscopic tests, such as X-ray photoelectron spectroscopy, scanning electron microscopy, and inductively coupled plasma mass spectrometry. The long-term degradation of concrete was predicted by utilizing a multi-scale model of calcium leaching, which considered the micro-pore structure of cement hydrates flux with time. The simulated results using this calcium leaching model showed a good agreement with other experiments. Finally, a real case study including field inspection was performed and the long-term durability of dam concrete was predicted through microscopic tests and finite element analysis method. It implies that the proposed method could provide calculation and theoretical basis for the durability analysis of concrete dams due to calcium leaching. [ABSTRACT FROM AUTHOR]

Abstract: A catalytic intramolecular ylide annulation for the controllable construction of benzobicyclo[4.3.0] ring systems with three continuous stereogenic centers is developed in a single manipulation. In the presence of 20mol% of triphenylphosphine, the reactions of compounds 1a–1f afford benzobicyclo[4.3.0] compounds 3 and 4 as major products, respectively, with excellent diastereoselectivities in good to excellent yields, depending on the base used. In addition, 2-methyl α,β-unsaturated esters 2a–2c also work well to give the corresponding benzobicyclo[4.3.0] compounds with one quaternary carbon center with high diastereoselectivities in good yields under the same conditions. [Copyright &y& Elsevier]

The first time steroselective synthesis of (Z)-β-bromo Baylis–Hillman ketones has been achieved using a one-pot three-component reaction. The new system uses MgBr2 as both the Lewis acidic promoter and the bromine source for the Michael-type addition with α,β-acetylenic ketones to form an active β-bromo allenolate intermediate, which in turn attacks various aldehydes to afford β-bromo Baylis–Hillman adducts in good yields and Z-selectivity. [Copyright &y& Elsevier]

N,N-Dichloro-o-nitrobenzenesulfonamide (2-NsNCl[sub 2]) was found to be an effective electrophilic nitrogen source for the direct diamination of α,β-unsaturated ketones without the use of any metal catalysts. The reaction is very convenient to carry out without the protection of inert gases. Molecular sieves (4 Å) and temperature were found to play key roles in controlling the formations of 3-trichloromethyl and dichloromethyl imidazoline products (16 examples). The 2-Ns-protection group of the resulting diamine products can be easily cleaved under mild Fukuyama's conditions. A new mechanism hypothesis of [2+3] cyclization and N-chlorination has been proposed to explain the product structures, particularly their regio- and stereochemistry. [ABSTRACT FROM AUTHOR]

Several chemical changes in soil are associated with plant growth-promoting rhizobacteria (PGPR). Some bacterial strains directly regulate plant physiology by mimicking synthesis of plant hormones, whereas others increase mineral and nitrogen availability in the soil as a way to augment growth. Identification of bacterial chemical messengers that trigger growth promotion has been limited in part by the understanding of how plants respond to external stimuli. With an increasing appreciation of how volatile organic compounds signal plants and serve in plant defense, investigations into the role of volatile components in plant-bacterial systems now can follow. Here, we present chemical and plant-growth data showing that some PGPR release a blend of volatile components that promote growth of Arabidopsis thaliana. In particular, the volatile components 2,3-butanediol and acetoin were released exclusively from two bacterial strains that trigger the greatest level of growth promotion. Furthermore, pharmacological applications of 2,3-butanediol enhanced plant growth whereas bacterial mutants blocked in 2,3-butanediol and acetoin synthesis were devoid in this growth-promotion capacity. The demonstration that PGPR strains release different volatile blends and that plant growth is stimulated by differences in these volatile blends establishes an additional function for volatile organic compounds as signaling molecules mediating plant-microbe interactions. [ABSTRACT FROM AUTHOR]

Highly stereoselective synthesis of (E)-β-bromo Baylis-Hillman ketones has been achieved using a three-component X–C/C–C formation reaction. The synthesis involves the Michael-type addition of TiBr4 to α,β-acetylenic ketones without using any bases and carbonyl coupling with aldehydes. Modest yields (50–65%) and complete E/Z geometric selectivity have been realized for 10 examples. [ABSTRACT FROM AUTHOR]

High-nitrogen multicore metal complexes M 8 N 60 is proposed; M 8 N 60 is high detonation heat and high stability; Structure and stability can be controlled by electron spin multiplets for M 8 N 60. [Display omitted] Due to electronic structure of conventional primary explosives with CHNO, such systems present a significant challenge to improving energy utilization. In this work, high-nitrogen multicore metal Complex M 8 N 60 (M = Cr, Mo, W, Mn, Re) were built as primary explosive by density functional theory (DFT) to contain metal–metal multiple bonds (M≡M) and multipoint coordination ability. Metal-metal(M−M) and metal–ligand (M−N) fuzzy bond orders were calculated by DFT at the PBE/LanL2DZ level, which suggests M 8 N 60 is stable and a high detonation heat compound. Moreover, the stability of spin state of transition metals can be changed with the spin multiplet because of spin orbitals. Thus, M 8 N 60 may be a class of new high-energy primary explosive and spintronic material because of high electronic polarizability, which can realize information storage dependent on electron spins. [ABSTRACT FROM AUTHOR]

Ink analysis played an important role in document examination, but the limited dataset made it difficult for many algorithms to distinguish inks accurately. This article aimed to evaluate the feasibility of two data augmentation (DA) methods, Gaussian noise data augmentation (GNDA) and extended multiplicative signal augmentation (EMSA), for the classification of felt‐tip pen ink brands. Four brands of felt‐tip pens were analyzed using FT‐IR spectroscopy. Five classification models were used, convolutional neural network (CNN), K‐nearest neighbor (KNN), support vector machine (SVM), random forest (RF), and partial least squares discriminant analysis (PLS‐DA). The results showed that the datasets generated by GNDA and EMSA are similar to the original datasets and have some diversity. The EMSA method had optimal classification results when combined with CNN, with classification accuracy (ACC), precision (PRE), recall (REC) and F1 score reaching 99.86%, 99.87%, 99.86%, 99.86%, and 99.86%, compared with GNDA‐CNN method (ACC = 80.90%, PRE = 87.34%, REC = 81.62%, F1 score = 79.23%). This study shows that when raw spectral data is small, DA methods can be combined with neural network models to identify ink brands effectively. [ABSTRACT FROM AUTHOR]

Copper‐based halides, a type of perovskite derivative, inherit their excellent optoelectronic properties and solution processability and also have the advantages of being nontoxic and stable. Despite the tremendous achievements of microfabrication in conventional halide perovskites, reports on copper‐based halide array devices are rare due to their difficult high‐quality crystallization. Here, by introducing single‐crystal thin films grown by space confinement method as substrates, reliable photolithography based on their single crystals is successfully achieved and controllable homoepitaxial single‐crystal arrays is demonstrated. By adjusting the substrate, angle, and growth time, the orientation, arrangement, and size of arrays could be controlled. Temperature and time are used to regulate the growth stage to obtain clean and appropriately sized arrays. ITO/Cs3Cu2I5/ITO neuromorphic device based on homoepitaxial arrays is developed. The variation of synaptic plasticity could be controlled by the number and frequency of light pulses. The device successfully simulated the process of “learning, forgetting, and relearning” in the human brain, demonstrating the potential of application in sensing‐storage‐computing‐integrated devices. [ABSTRACT FROM AUTHOR]

ZnO, as a potential candidate, has attracted extensive attention in optoelectronics, energy systems and other fields. However, the wide bandgap of ZnO severely limits its application in a wide range of photoresponse, and preparing p-type ZnO is another stumbling block that hinders the development of ZnO-based devices. Here, a high-performance photodetector with a wider spectral detection range from UV–vis to NIR builds on the structure of p-ZnO/Al 2 O 3 /n-Si is fabricated. The PD exhibits a marked sensitivity (75,000%), excellent responsivity (13.80 A W−1, 365 nm), high specific detectivity (> 1012 Jones), fast response (< 100 μs), which indicates that inserting an insulated Al 2 O 3 layer between an n-type semiconductor and a p-type semiconductor is a fruitful method to enhance carriers separation and collection efficiency. The carrier transport mechanism at the interface of PDs with different Al 2 O 3 thickness is based on the quantum mechanical of Fowler-Nordheim tunneling or direct tunneling. Additionally, the overall signal levels of the photodetector could be further optimized using the piezo-phototronic effect. This study demonstrates an alternative route to implement high-efficiency photodetectors with a broader response range and provides an in-depth understanding of regulating carrier tunneling of the p-ZnO/Al 2 O 3 /n-Si heterojunction using the piezo-phototronic effect. [Display omitted] • A high-performance photodetector with a broad spectral range from UV–vis to NIR is fabricated. • The carrier transport mechanism of devices with different insulation thicknesses is systematically studied. • The photoelectric performance of the detector is significantly improved by piezo-phototronic effect. [ABSTRACT FROM AUTHOR]

Describes a study on the development of a novel tandem asymmetric carbon-carbon formation process promoted by a Lewis acid. Stereospecific synthesis of the unusual Baylis-Hillman adducts, beta-branched alpha-(aminoalkyl)-acrylates; Anionic additions of vinylcuprates to p-toluenesulfinimines.