Remote Functionalization of Inert C(sp)-H Bonds via Dual Catalysis Driven by Alkene Hydrofluoroalkylation Using Industrial Feedstocks.

We have developed a dual-catalytic system capable of site-selective azidation of inert C(sp)-H bonds with concomitant and modular anti-Markovnikov alkene fluoroalkylation. The protocol leverages the synergetic cooperation of both the photocatalyst and earth-abundant iron catalyst to deliver two radical species in succession to minimally functionalized alkenes. This powerful catalyst system exhibits broad scope, mild conditions, and excellent regioselectivity for a variety of substrates and fluoroalkyl fragments.

Lewis acid-promoted direct synthesis of isoxazole derivatives.

Isoxazole derivatives were synthesized via a one-pot method utilizing 2-methylquinoline derivatives as template substrates, sodium nitrite as a nitrogen-oxygen source, and solely using aluminum trichloride as the additive. This approach circumvents the need for costly or highly toxic transition metals and presents a novel pathway for the synthesis of isoxazole derivatives.

The Influence of Fly Ash on the Tensile Creep Prediction of High-Strength Concrete at Early Ages.

In this study, the tensile creep (TC) of high-strength concrete (HSC) containing 30 wt% fly ash was measured at early ages to investigate the applicability of creep prediction models for concrete containing FA, and to provide ideas to study the prediction model of concrete creep containing other SCMs in the future. The TC values obtained from the experiment were compared with the predicted values of six TC models. Then the accuracy of different models was evaluated by the ratio of predicted values to experimental values.

A Bifunctional CdS/MoO /MoS Catalyst Enhances Photocatalytic H Evolution and Pyruvic Acid Synthesis.

The best use of photogenerated electrons and holes is crucial to boosting photocatalytic activity. Herein, a bifunctional dual-cocatalyst-modified photocatalyst is constructed based on CdS/MoO /MoS hollow spheres for hydrogen evolution coupled with selective pyruvic acid (PA) production from lactic acid (LA) oxidation. MoS and MoO are simultaneously obtained from the conversion of CdMoO in one step.

Direct Transformation of Nitrogen-Containing Methylheteroarenes to Heteroaryl Nitrile by Sodium Nitrite.

The cyanation reaction of methylheteroarenes with acetyl chloride and sodium nitrite via the radical process in high yields is reported. According to the control experiments, the reaction mechanism underwent radical progress. It is very useful in the pharmacy industry due to its metal-free and easy treatment conditions.

Matrix Measure-Based Event-Triggered Impulsive Quasi-Synchronization on Coupled Neural Networks.

In this article, the quasi-synchronization for a kind of coupled neural networks with time-varying delays is investigated via a novel event-triggered impulsive control approach. In view of the randomly occurring uncertainties (ROUs) in the communication channels, the global quasi-synchronization for the coupled neural networks within a given error bound is considered instead of discussing the complete synchronization. A kind of distributed event-triggered impulsive controllers is presented with considering the Bernoulli stochastic variables based on ROUs, which works at each event-triggered impulsive instant.

Dopant-free hole-transporting materials for stable Sb(S,Se) solar cells.

Herein, we demonstrate that a thiophene-modified quinoxaline core small molecule can be applied in Sb(S,Se) solar cells. We reveal that the interaction between thiophene and Sb(S,Se) through the Sb-S bond essentially improves the interfacial hole-extraction ability. This study provides a cost-effective dopant-free hole-transporting material for inorganic thin film solar cell applications with excellent stability.

Matrix Measure-Based Projective Synchronization on Coupled Neural Networks With Clustering Trees.

This article mainly studies the projective quasisynchronization for an array of nonlinear heterogeneous-coupled neural networks with mixed time-varying delays and a cluster-tree topology structure. For the sake of the mismatched parameters and the mutual influence among distinct clusters, the exponential and global quasisynchronization within a prescribed error bound instead of complete synchronization for the coupled neural networks with clustering trees is investigated. A kind of pinning impulsive controllers is designed, which will be imposed on the selected neural networks with some largest norms of error states at each impulsive instant in different clusters.

CsPbBr Nanocrystal Induced Bilateral Interface Modification for Efficient Planar Perovskite Solar Cells.

Organic-inorganic halide perovskite solar cells (PSCs) have drawn tremendous attention owing to their remarkable photovoltaic performance and simple preparation process. However, conventional wet-chemical synthesis methods inevitably create defects both in the bulk and at the interfaces of perovskites, leading to recombination of charge carriers and reduced stability. Herein, a bilateral interface modification to perovskites by doping room-temperature synthesized CsPbBr nanocrystals (CN) is reported.

Revealing composition and structure dependent deep-level defect in antimony trisulfide photovoltaics.

Antimony trisulfide (SbS) is a kind of emerging light-harvesting material with excellent stability and abundant elemental storage. Due to the quasi-one-dimensional symmetry, theoretical investigations have pointed out that there exist complicated defect properties. However, there is no experimental verification on the defect property.

Direct Hydrothermal Deposition of Antimony Triselenide Films for Efficient Planar Heterojunction Solar Cells.

Antimony selenide (SbSe) has attracted increasing attention in photovoltaic applications due to its unique quasi-one-dimensional crystal structure, suitable optical band gap with a high extinction coefficient, and excellent stability. As a promising light-harvesting material, the available synthetic methods for the fabrication of a high-quality film have been quite limited and seriously impeded both the fundamental study and the efficiency improvement. Here, we developed a facile and low-cost hydrothermal method for in situ deposition of SbSe films for solar cell applications.

Sequential Coevaporation and Deposition of Antimony Selenosulfide Thin Film for Efficient Solar Cells.

Antimony selenosulfide (Sb (S,Se) ) is an emerging low-cost, nontoxic solar material with suitable bandgap and high absorption coefficient. Developing effective methods for fabricating high-quality films would benefit the device efficiency improvement and deepen the fundamental understanding on the optoelectronic properties. Herein, equipment is developed that allows online introduction of precursor vapor during the reaction process, enabling sequential coevaporation of Sb Se and S powders for the deposition of Sb (S,Se) thin films.

Protective Geopolymer Coatings Containing Multi-Componential Precursors: Preparation and Basic Properties Characterization.

This paper presents an experimental investigation on geopolymer coatings (GPC) in terms of surface protection of civil structures. The GPC mixtures were prepared with a quadruple precursor simultaneously containing fly ash (FA), ground granulated blast-furnace slag (GBFS), metakaolin (MK), and Portland cement (OPC). Setting time, compressive along with adhesive strength and permeability, were tested and interpreted from a perspective of potential applications.

Metal chloride perovskite thin film based interfacial layer for shielding lithium metal from liquid electrolyte.

Fabricating a robust interfacial layer on the lithium metal anode to isolate it from liquid electrolyte is vital to restrain the rapid degradation of a lithium metal battery. Here, we report that the solution-processed metal chloride perovskite thin film can be coated onto the lithium metal surface as a robust interfacial layer to shield the lithium metal from liquid electrolyte. Via phase analysis and density functional theory calculations, we demonstrate that the perovskite layer can allow fast lithium ion shuttle under a low energy barrier of 0.

General Synthesis of Lead-Free Metal Halide Perovskite Colloidal Nanocrystals in 1-Dodecanol.

Lead halide perovskite nanocrystals (NCs) exhibit great application potential in optoelectronic devices because of their tunable band gaps and facile colloidal synthesis, but they suffer from serious lead toxicity and instability. It is highly desirable to substitute lead with other elements to acquire nontoxic and environmentally friendly lead-free perovskite NCs for optoelectronic devices. Here, we report a general method for the colloidal synthesis of a series of bismuth/antimony-based halide perovskite NCs with various constituents and optical band gaps from 1.

Composition engineering of SbS film enabling high performance solar cells.

SbS is a kind of stable light absorption materials with suitable band gap, promising for practical applications. Here we demonstrate that the engineering on the composition ratio enables significant improvement in the device performance. We found that the co-evaporation of sulfur or antimony with SbS is able to generate sulfur- or antimony-rich SbS.

Interfacial Engineering by Indium-Doped CdS for High Efficiency Solution Processed Sb(SSe ) Solar Cells.

Sb(SSe ) alloy material is a kind of encouraging material for realistically apposite solar cell because it benefits from high absorption coefficient, suitable bandgap, superior stability, and plentiful elemental storage. Interfacial engineering is vital for effective charge carrier transport in solar cells, which could upgrade the photoelectric conversion efficiency (PCE). Herein, as an interlayer, indium-doped CdS thin film fabricated by chemical bath deposition is found to remarkably enhance the photovoltaic performance of Sb(SSe ) solar cells.

n-Type Doping of SbS Light-Harvesting Films Enabling High-Efficiency Planar Heterojunction Solar Cells.

SbS is a kind of new light-absorbing material possessing high stability in ambient environment, high absorption coefficient in the visible range, and abundant elemental storage. To improve the power conversion efficiency of SbS-based solar cells, here we control the defect in SbS absorber films. It is found that the increase of sulfur vacancy is able to upgrade photovoltaic properties.

VO as Hole Transporting Material for Efficient All Inorganic SbS Solar Cells.

This research demonstrates that VO is able to serve as hole transporting material to substitute organic transporting materials for SbS solar cells, offering all inorganic solar cells. The VO thin film is prepared by thermal decomposition of spin-coated vanadium(V) triisopropoxide oxide solution. Mechanistic investigation shows that heat treatment of VO layer has crucial influence on the power conversion efficiency of device.

Bottom-up synthesis of nitrogen-doped graphene sheets for ultrafast lithium storage.

A facile bottom-up strategy was developed to fabricate nitrogen-doped graphene sheets (NGSs) from glucose using a sacrificial template synthesis method. Three main types of nitrogen dopants (pyridinic, pyrrolic and graphitic nitrogens) were introduced into the graphene lattice, and an inimitable microporous structure of NGS with a high specific surface area of 504 m(2) g(-1) was obtained. Particularly, with hybrid features of lithium ion batteries and Faradic capacitors at a low rate and features of Faradic capacitors at a high rate, the NGS presents a superior lithium storage performance.

An ultracompact multimode interference wavelength splitter employing asymmetrical multi-section structures.

By using the film mode matching method, a novel design for asymmetrical multi-section 1.55/1.31 μm wavelength splitter based on multimode interference has been proposed and simulated, which can be effectively applied to wavelength multiplexer, self-biased photodiode, and other optical devices.

Increased genetic vulnerability to smoking at CHRNA5 in early-onset smokers.

Context: Recent studies have shown an association between cigarettes per day (CPD) and a nonsynonymous single-nucleotide polymorphism in CHRNA5, rs16969968.

Objective: To determine whether the association between rs16969968 and smoking is modified by age at onset of regular smoking.

Data Sources: Primary data.