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Light-induced deprotonation of molecules is an important process in photochemical reactions. Here, we theoretically investigate the tunneling deprotonation of H 2 + and its asymmetric isotopologues driven by circularly polarized THz laser pulses. The quasi-static picture shows that the field-dressed potential barrier is significantly lowered for the deprotonation channel when the mass asymmetry of the diatomic molecule increases. Our numerical simulations demonstrate that when the mass symmetry breaks, the tunneling deprotonation is significantly enhanced and the proton tunneling becomes the dominant dissociation channel in the THz driving fields. In addition, the simulated nuclear momentum distributions show that the emission of the proton is directed by the effective vector potential for the deprotonation channel and, meanwhile, the angular distribution of the emitting proton is affected by the alignment and rotation of the molecule induced by the rotating field. [ABSTRACT FROM AUTHOR]

We experimentally study two-body Coulomb explosions of CO2, O2, and CH3Cl molecules in intense femtosecond laser pulses. We observe an obvious variation in the ionic angular distribution of the fragments with respect to the kinetic energy releases (KERs). Using a classical model based on ab initio potential energy curves, we find that the dependence of the ionic angular distribution on the KER is relevant to the fact that the accurate potential energy deviates significantly from the value determined by applying the Coulomb interaction approximation at a relatively small internuclear distance of the molecule. We show that the KER-dependent ionic angular distribution provides an effective way to determine the critical internuclear distance at which the Coulomb interaction approximation holds or breaks down without relying on the knowledge of the accurate potential energy curves. [ABSTRACT FROM AUTHOR]

With a classical trajectory Monte Carlo model, we systematically study the laser intensity and field amplitude ratio dependence of nonsequential double ionization by counter-rotating two-color circularly polarized fields (800 and 1600 nm). The results show that the optimized field amplitude ratio changes with the laser intensity, which is attributed to the shift of the most probable amplitude ratio of electron returning with the laser intensity. Moreover, the laser intensity-dependent double ionization probability curve shows a remarkable dip in the transition region between the nonsequential and sequential channels. It can be well explained by the reduction of the probability of electron returning with the increase of the laser intensity. [ABSTRACT FROM AUTHOR]

The momentum distribution of photoelectrons in H2+ molecules subjected to an attosecond pulse is theoretically investigated. To better understand the laser–molecule interaction, we develop an in-line photoelectron holography approach that is analogous to optical holography. This approach is specifically suitable for extracting the amplitude and phase of the forward-scattered electron wave packet in a dissociating molecule with atomic precision. We also extend this approach to imaging the transient scattering cross-section of a molecule dressed by a near infrared laser field. This attosecond photoelectron holography sheds light on structural microscopy of dissociating molecules with high spatial-temporal resolution. [ABSTRACT FROM AUTHOR]

To prepare high-performance asphalt cold replacement liquids, a composite modification preparation process was used to synthesize a styrene–butadiene–styrene (SBS) block copolymer, styrene–butadiene–rubber (SBR) copolymer, and polyphosphate acid (PPA), erucamide/diesel/acrylic ester as surfactants/diluents/reinforcing agent respectively. These six were blended to prepare an asphalt cold replenishment liquid (ACRL), and its modification effect on base asphalt was studied using base asphalt as the control group. A comparative study was conducted on the high- and low-temperature rheological properties and microstructure. The modification mechanisms of high-temperature asphalt cold replenishment liquid (H-ACRL) and low-temperature asphalt cold replenishment liquid (L-ACRL) were studied through dynamic shear rheometry, bending beam rheometry, Fourier-transform infrared spectroscopy, fluorescence microscopy, and atomic force microscopy. The results showed that the optimal dosages of PPA/SBS/SBR in H-ACRL and L-ACRL were (1.2%/5%/3%) and (0.9%/4%/4%), respectively. Within the optimal dosage range, the particles in the cold replenishment fluid were uniformly dispersed in the asphalt to form a dense and continuous network. No new functional groups were generated during the preparation of H-ACRL and L-ACRL, showing that the modifiers (surfactants/diluents/reinforcing agent) were only physically blended with the asphalt. [ABSTRACT FROM AUTHOR]

With the development of emerging information technology, the traditional management methods of marine fishes are slowly replaced by new methods due to high cost, time-consumption and inaccurate management. The update of marine fishes management technology is also a great help for the creation of smart cities. However, some new methods have been studied that are too specific, which are not applicable for the other marine fishes, and the accuracy of identification is generally low. Therefore, this paper proposes an ecological Internet of Things (IoT) framework, in which a lightweight Deep Neural Networks model is implemented as a image recognition model for marine fishes, which is recorded as Fish-CNN. In this study, multi-training and evaluation of Fish-CNN is accomplished, and the accuracy of the final classification can be fixed to 89.89%–99.83%. Moreover, the final evaluation compared with Rem-CNN, Linear Regression and Multilayer Perceptron also verify the stability and advantage of our method. [ABSTRACT FROM AUTHOR]

We theoretically investigate nonadiabatic effects in tunneling ionization of a hydrogen atom induced by a few-cycle elliptically polarized laser pulse. We find a deflection angle between the maximum of the photoelectron momentum distribution and the direction of the negative vector potential corresponding to the electric-field peak. This deflection angle mainly originates from the fact that the instant of the maximal ionization rate does not exactly correspond to the instant of the electric-field peak in the few-cycle elliptically polarized laser pulse, revealing an ionization time shift between those two instants. The ionization time shift is a result of the nonadiabatic effect induced by the envelope of the few-cycle elliptically polarized laser pulse, which disappears in a long-pulsed laser. Our study is useful for understanding attoclock experiments using few-cycle elliptically polarized laser pulses. [ABSTRACT FROM AUTHOR]

In industrial recirculating aquaculture systems (IRAS), the autonomous decision control of feeding strategies remains a practical concern. Conventionally, control schemes were established from data‐driven view, which fails to comprehensively perceive activity status of fishes. To deal with this issue, a deep vision sensing‐based fuzzy control scheme is proposed for smart feeding in IRAS. In the first stage, a deep learning‐based object detection model is introduced to capture two aspects features as the decision factors: residual bait and eating frequency. In the second stage, a fuzzy neural network model is formulated to calculate control decision strategies via fuzzy inference. And experiments on real‐world visual scenes are conducted to verify the proposal. [ABSTRACT FROM AUTHOR]

Coherent superposition of electronic states induces attosecond electron motion in molecules. We theoretically investigate the strong-field ionization of this superposition state by numerically solving the time-dependent Schrödinger equation. In the obtained photoelectron momentum distribution, an intriguing bifurcation structure appears in the strong-field holographic interference pattern. We demonstrate that this bifurcation structure directly provides complete information about the status of the transient wave function of the superposition state: the horizontal location of the bifurcation in the momentum distribution reveals the relative phase of the involved components of the superposition state and the vertical position indicates the relative coefficient. Thus, this bifurcation structure takes a snapshot of the transient electron wave packet of the superposition state and provides an intuitive way to monitor electron motion in molecules. [ABSTRACT FROM AUTHOR]

Radioactive iodine is severely hazardous to human health and the environment because of its high specific activity and environmental mobility. In this article, three covalent organic frameworks (COFs) (named as DbTd‐COF, DpTd‐COF, and DaTd‐COF) were prepared for the removal of iodine in both gas and solution states. The COFs were obtained by the solvothermal reaction of 1,3,5,7‐tetrakis (4‐formylphenyl) adamantane (TFPA) with benzidine, 2,5‐diaminopyridine, and p‐phenylenediamine, respectively. The obtained samples were characterized by SEM, FT‐IR, TGA, and nitrogen adsorption‐desorption analysis. The rigid linker of phenzyl chains helps to improve the stability of the polymer. DbTd‐COF and DaTd‐COF show excellent thermomechanical stability with a decomposition temperature of over 400 °C. DbTd‐COF and DaTd‐COF show good uptake capacities of 4.93 and 4.48 g g−1 for iodine vapor capture, respectively. DpTd‐COF shows a slightly smaller iodine uptake of 3.43 g g−1. XPS results indicated that iodine was captured in the form of its polyiodide anions. A better recyclability can be obtained after four cycle runs. In addition, DaTd‐COF shows good removal of iodine (concentration: 500 mg L−1) from cyclohexane solution with an adsorption capacity of 666.79 mg g−1. [ABSTRACT FROM AUTHOR]

By numerically solving the three-dimensional time-dependent Schrödinger equation, we theoretically investigate the dynamic interference of the hydrogen atom in intense arbitrarily polarized high-frequency XUV pulses with and without the non-dipole correction included. Our results show a clear shift of the dynamic-interference peaks in the photoelectron spectra from the linearly and circularly polarized XUV pulses, which can be attributed to the different AC Stark shifts of the ground state. The non-dipole correction for the electron–light interaction produces a similar peak shift along the propagation direction in the photoelectron momentum spectra for the linear and circular pulses. But no obvious non-dipole effect for the AC Stark shift of the ground state is identified for the light pulse with intensity around 1019 W cm−2. [ABSTRACT FROM AUTHOR]

A novel permselective film of electrodeposited polydopamine (PDA) on electrochemical reduced graphene oxide (erGO) surface was prepared. The obtained composite films were characterized by atomic force microscope (AFM), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The influences of permselectivity with different electropolymerized cycles and concentration of dopamine on electrochemical responses of biomolecules on electrode were investigated. It was found that the composite film held high cationic permeable to dopamine (DA) and good suppression of ascorbic acid (AA) and uric acid (UA) using CV. The anodic peak currents were proportional to dopamine concentration. The significant permselectivity suggested that the PDA/graphene‐modified electrode has opened a new route to high selective dopamine biosensor. [ABSTRACT FROM AUTHOR]

This article takes Guangzhou as an example, the application of color pavement of bus lane has been studied technically, adopting research methods of internal analysis and field practice. At present, there are mainly three kinds of color pavement bus lanes in China, such as color asphalt pavement, ordinary color aggregate pavement and two-component color ceramic particles, by comparing and analyzing the performance of these three kinds of color pavement, combining with various factors such as the geographical characteristics of Guangzhou, it is considered that the two-component color ceramic particle color road surface is more suitable for the construction of Guangzhou bus lanes. The technical requirements for the setting of the color pavement bus lane were prepared, the application technology of the experiement section was introduced to provide reference for the similar project. [ABSTRACT FROM AUTHOR]

The present work is focused on the fluidization behavior of different mixed binary nanoparticles (Fe 2 O 3 + SiO 2 , Fe 2 O 3 + TiO 2 , and Fe 2 O 3 + ZnO) under the influence of a vibrated field. The results reveal that the iron-containing nanoparticle mixtures with different mass fractions can achieve uniform fluidization in the initial bed height of 40 mm, amplitude of 3.0 mm, vibration frequency of 40 Hz, and binary mixtures containing nano-SiO 2 and nano-Fe 2 O 3 have commendable fluidization behavior. Richardson–Zaki equation index indicates that the particulate dispersion degree of the different proportion mixtures increases as the mass fraction of APF (agglomerate particulate fluidization) nanoparticle increases. For a binary nanoparticle mixture containing different proportions of high content nano-SiO 2 and nano-Fe 2 O 3 , n /4.65 is closer to 1 and the relative deviation is smaller than that containing a high content TiO 2 and ZnO, indicating that the system has a good dispersibility. [ABSTRACT FROM AUTHOR]

Better sensitivity and interface of ambient sampling/ionization mass spectrometry remain a challenge. Herein, a novel, plasma-based, ambient sampling/ionization/transmission (PASIT) integrated source in a pin-to-funnel configuration was developed for the sensitive analysis of complex samples. With the funnel sleeve directly affected by direct-current discharge plasma, PASIT combines the ability to sample/ionize analyte molecules and then efficiently collect/transport charged mass species under atmospheric pressure and consequently shows an improved sensitivity. The integrated source enhances the signal intensity by more than 2 orders of magnitude compared with the previous pin-to-plate plasma source without significant background addition. A surface limit of detection (LOD) of 130 fmol mm−2 (S/N = 3) has been achieved for clenbuterol on filter paper with an argon carrier gas. Demonstrated applications include the direct determination of active ingredients from drugs and symbolic compounds from natural plants and cholesterol from mouse brain tissue sections. [ABSTRACT FROM AUTHOR]

Using the classical ensemble method, we have investigated double ionization (DI) of stretched molecules by circularly polarized laser pulses. Back analysis of the DI trajectories shows that most DI occurs through a process of collision, indicating the nonsequential feature of DI. In contrast to the common recollision picture for nonsequential double ionization, here the first electron ionizes over the inner potential barrier of the molecule, moves directly towards the other nucleus and leads to excitation or ionization of the second electron by collision. The correlated momentum distributions for the electron pairs from this collision-induced nonsequential process show an obvious correlation pattern in the direction parallel to the molecular axis, whereas they show an anticorrelation pattern in the direction perpendicular to the molecular axis. [ABSTRACT FROM AUTHOR]

Chinese liquors are often a very important part of social event in China. Driven by high profit, some illegal traders often use inferior liquors instead of the products with high quality to cheat the customer. Therefore, it is highly required to authenticate Chinese liquors. In this paper a novel method based on ambient glow discharge ionization mass spectrometry has been developed to differentiate Chinese liquors. Volatile components from liquor samples were ionized by the plasma generated by glow discharge and then detected by a commercial linear ion trap mass spectrometer. Consequently, the fingerprint mass spectra of several Chinese liquors were obtained. Combined with principal component analysis, this new method was successfully applied to differentiate different brands of Chinese liquors without any sample pretreatment. Compared with conventional methods, this novel method has the advantages of easy operation, high speed, and high efficiency, which make it a potential tool in the fields of food safety, atmosphere chemistry. [ABSTRACT FROM AUTHOR]

Abstract: Using three-dimensional classical ensembles, we have investigated the enhancement of double ionization of perpendicularly aligned H 2 molecules by a 800nm laser pulse with intensity ranging from 1×1014 W/cm2 to 6×1014 W/cm2. The simulated results show that double ionization probability of H 2 strongly depends on R and reaches a maximum at an intensity independent critical distance R C ≈5a.u. Furthermore, the enhancement of double ionization is more pronounced in the cases of weaker or stronger fields. These results, a well indication of the influence of molecular structures and laser–molecule interactions on double ionization of diatomic molecules, are analyzed in detail and qualitatively explained based on the field-induced barrier suppression model and back analysis. [Copyright &y& Elsevier]