An enantioselective protonation strategy has been successfully applied to the synthesis of chiral α-tertiary azaarenes. With a dual catalytic system involving phosphoric acid and dicyanopyrazine-derived chromophore (DPZ) photosensitizer that is mediated by visible light, variety α-branched 2-vinylpyridines 2-vinylquinolines with N-aryl glycines underwent redox-neutral, radical conjugate addition–protonation process provided valuable 3-(2-pyridine/quinoline)-3-substituted amines in high...

We report herein a strategy to construct enantiopure inherently chiral macrocycles, ABCD-type heteracalix[4]aromatics, through catalytic enantioselective intramolecular C–N bond forming reaction. A ligand-palladium complex was found efficiently induce the inherent chirality of molecules during macrocyclization process with ee values up >99%. The resulting heteracalix[4]aromatics displayed excellent and pH-triggered switchable electronic circular dichroism circularly polarized luminescence properties.

Effects of gas flow rate on the length atmospheric pressure plasma jets have been investigated using a capillary dielectric barrier discharge configuration. For in only downstream region, three distinguishable modes jet versus argon rate, namely, laminar, transition, and turbulent mode, identified. case both upstream regions, curve has significant “dent” laminar mode for pure helium, neon, spraying into air ambient.

Abstract We report a synthetic strategy for chemoselective switch and diastereo‐divergent approach the asymmetric reaction of 5 H ‐oxazol‐4‐ones N ‐itaconimides catalyzed by l ‐ tert ‐leucine‐derived tertiary amine–urea compounds. The was modulated to harness either tandem conjugate addition–protonation or [4+2] cycloaddition as major product with excellent enantio‐ diastereoselectivities. Subjecting enantio‐enriched products basic silica gel reagent yields diastereomer vis‐à‐vis directly...

An enantioselective cascade aerobic oxidation and semipinacol rearrangement reaction of 2-aryl-3-alkyl-substituted indoles via visible-light-driven cooperative organophotoredox H-bonding catalysis is reported. The current method provides an expedient sustainable approach to furnish a variety valuable chiral 2-aryl-2-alkyl-substituted indolin-3-ones in 64-90 % yield with 58-94 ee. Preliminary control experiments present important insights into the stereochemistry.

A chiral bicyclic guanidine-catalyzed enantioselective sulfenylation of 3-substituted oxindoles to N-(sulfanyl)succinimides has been developed. series unprecedented 3-sulfenylated oxindoles, such as 3-benzyl/alkyl-substituted 3-benzyl/alkyloxindoles, were obtained with high enantioselectivities (up 98% ee). This methodology is also effective for the first asymmetric benzofuran-2(3H)-ones, providing 3-benzyl-3-benzylthio-substituted benzofuran-2(3H)-ones satisfactory results 95%

In the experiment of plasma jets generated in a tube dielectric barrier discharge configuration, three distinguishable modes, namely, laminar, transition, and turbulent jet have been identified. Flows helium, neon, argon gases shared hydrodynamic law when their spraying into ambient air atmospheric pressure room temperature. Aiming to reveal basic processes, we propose that length is mainly determined by reactions involving metastable atoms. These processes are responsible for variation...

An asymmetric arylation of benzofuran-2(3<italic>H</italic>)-ones with 1-naphthols has been developed through a cooperative visible light photocatalysis hydrogen-bond catalysis.

Abstract The radical cascade reaction is considered as one of the most powerful methods to build molecular complexity. However, highly stereoselective intermolecular reactions that can produce complex cyclic compounds bearing multiple stereocenters via visible-light-induced photocatalysis have been challenging yet desirable. Herein we report a facile and efficient synthesis multi-substituted trans -fused hexahydrocarbazoles readily available tryptophans acrylamides enabled by photoredox...

The rapid detection of the elements nitrogen (N), phosphorus (P), and potassium (K) is beneficial to control compound fertilizer production process, it great significance in industry. aim this work was compare ability laser-induced breakdown spectroscopy (LIBS) coupled with support vector regression (SVR) obtain an accurate reliable method for all three elements. A total 58 samples were provided by Anhui Huilong Group. collection divided into a calibration set (43 samples) prediction (15...

We present a novel method for investigating laser-driven dynamic fragmentation in tin using situ X-ray diffraction. Our experimental results demonstrate the feasibility of simultaneously identifying phase and temperature fragments through analysis diffraction pattern. Surprisingly, we observe deviation from widely accepted isentropic release assumption, with being found to be more than 100 K higher expected, owing plastic work during fragmentation. findings are further verified extensive...

Abstract We report a synthetic strategy for chemoselective switch and diastereo‐divergent approach the asymmetric reaction of 5 H ‐oxazol‐4‐ones N ‐itaconimides catalyzed by l ‐ tert ‐leucine‐derived tertiary amine–urea compounds. The was modulated to harness either tandem conjugate addition–protonation or [4+2] cycloaddition as major product with excellent enantio‐ diastereoselectivities. Subjecting enantio‐enriched products basic silica gel reagent yields diastereomer vis‐à‐vis directly...

Despite the rapid development of concepts used in current map-matching algorithms, continuous movement a vehicle is often ignored or just limited to 1 several previous matches. This may result errors complicated situations such as at Y-junctions, and entrance exit ramps highway. The trajectory-based algorithm, which determines matching road by comparing trajectory against candidate roads, has potential overcome this limitation. However, curve-to-curve simple form fails address this. key...

Driving road identification is the key issue of a vehicle navigation system that supports various services intelligent transportation systems. The method for driving also known as map matching (MM). In spite development MM algorithms, limitations still exist in obtaining positioning data and preparing candidate roads (CRs) may result mismatches some special difficult configurations such flyovers parallel roads. To overcome limitations, an integrated trajectory-based (tbMM) proposed based on...

The de-excitation probability of argon 1s5 and 1s3 metastable atoms on aluminum (alloy 2024), stainless steel (304), silicon (100), quartz (JGS1) Pyrex surfaces is measured with a low pressure (1–5 mTorr) pulsed capacitively coupled plasma. deduced from the loss rate in late afterglow, which obtained temporal evolution atom density by laser absorption. Under condition, mainly due to volume diffusion surface. for both Ar*(1s5) Ar*(1s3) ranges 0.74 0.88 these five materials, an uncertainty...

A relationship between the apparent secondary electron yield () and oxygen coverage/oxide layer thickness on an aluminum cathode is obtained in experiment under a controlled environment. The deduced from breakdown voltage two parallel plate electrodes 360 mTorr argon environment using simple Townsend model with assumption that variation of dominated by ion induced processes. measured semi situ x-ray photoemission spectroscopy equipment which directly attached to discharge chamber. It found...

Real-time monitoring of the mechanical behavior cathode materials during electrochemical cycle can help obtain an in-depth understanding working mechanism lithium-ion batteries. The LiMn2O4 composite electrode is employed as in this artificial cell, which conceived and produced along with a chemo-mechanical coupling measurement system. multi-layer beam made monitored real time using CCD camera to track its curvature deformation. Experiments show that decreases extraction lithium ions...

The energy evolution of surface plasmons on an aluminum during the oxidation process is investigated using electron loss spectroscopy (EELS) and x-ray photoemission (XPS). plasmon determined from location peak in EELS spectra; at same time, total oxygen coverage (in submonolayer regime) oxide layer thickness multilayer are obtained profiles O 1s Al 2p lines XPS spectra. In regime, slightly decreases with θ when 1, rate decrease becomes larger as increases. This behaviour can be explained by...

The initial oxidation of poly-crystalline aluminum is investigated using x-ray photoelectron spectroscopy (XPS). total oxygen coverage and the oxidic are obtained from O 1s Al 2p peaks in XPS spectra. A linear relationship found between coverage. critical representing start nucleation process determined to be 0.07 ± 0.02. It proposed that site-exchange caused by a repulsive interaction chemisorbed island substrate strength this increases with size island. Based on consideration, simple model...