Dispersive Charge Research Articles

Construction of sublimable pure organic ionic material with high solid luminescence efficiency based on anion-π+ interactions tuning strategy

Charged species with π-conjugated moieties play a vital role in the development of organic electronic field, but the executable strategy of attaining high luminescent efficiency with sublimable pure organic salts is rare due to their inherent ionic nature and low vapor pressure, extremely restricting their application in the field of organic optoelectronics via common vacuum evaporation method. In this work, a series of central-type organic salts based polycyclic aromatic hydrocarbon (PAH) core are developed because of their potential higher luminescence efficiency than that of reported terminal-type organic salts like protonated pyridine framework, and they are equipped with aggregation-induced emission enhancement performance and tunable emission. The analyses of spectral data, crystal packing, and theoretical simulation demonstrate that rationally dispersing surface charge of large π cation by regulating donor–acceptor (D-A) distribution facilitates to increase anion-π+ interactions and suppress the free rotation of phenyl groups, contributing to the fluorescence enhancement in the solid state. Notably, after tuning counter-ions’ steric hindrance and dispersed charges (BArF24−), the sublimable pure organic ionic materials are obtained with high solid luminescence efficiency, and its vacuum-evaporated organic light-emitting diode (OLED) is prepared based on pure organic salt with bright yellow emission. Such inspiring results offer us new alternative material system for the organic optoelectronics.

Excitation spectrum of spin-1 Kitaev spin liquids

We study the excitation spectrum of the spin-1 Kitaev model using the symmetric tensor network. By evaluating the virtual order parameters defined on the virtual Hilbert space in the tensor network formalism, we confirm the ground state is in a $\mathbb{Z}_2$ spin liquid phase. Using the correspondence between the transfer matrix spectrum and low-lying excitations, we find that contrary to the dispersive Majorana excitation in the spin-1/2 case, the isotropic spin-1 Kitaev model has a dispersive charge anyon excitation. Bottom of the gapped single-particle charge excitations are found at $\mathbf{K}, \mathbf{K}'=(\pm2\pi/3, \mp 2\pi/3)$, with a corresponding correlation length of $\xi \approx 6.7$ unit cells. The lower edge of the two-particle continuum, which is closely related to the dynamical structure factor measured in inelastic neutron scattering experiments, is obtained by extracting the excitations in the vacuum superselection sector in the anyon theory language

Transient behavior of electrical conductivity in low‐density polyethylene in the presence of acetophenone

AbstractThe transient current in low‐density polyethylene (LDPE) is studied, particularly in the presence of the small organic molecule acetophenone (ACP). Crosslinked LDPE is used extensively in high‐voltage power transmission, and acetophenone is a common byproduct of the crosslinking chemistry. Time‐dependent current measurements of LDPE with and without ACP soaked into the polymer as well as at one or both electrodes are performed by applying step voltages. The results demonstrate that the presence of ACP causes a deviation in the predicted power‐law current decay, suggesting that electron and hole injection at the anode and cathode, respectively, are affected by the presence of this small organic molecule. ACP contributes both to the ionic conduction and charge hopping mechanism. The charge mobility depends on the applied electric field and the sample thickness. The results suggests that the dispersive charge transport phenomenon influences the measured current. This study shows how such a molecule may alter charge transport in polyethylene.

Calculation of equivalent charge weight per delay and vibration velocity prediction for millisecond delay blasting

Drilling and blasting is the most economical rock fracture technology in water conservancy, transportation, mining and tunnel engineering. And the application of nonel detonator network in rock blasting is still the most widely used initiation method in engineering blasting practice. Due to the detonator delay error, there is a deviation between the actual initiation time and designed initiation time in the Nonel detonation network, which will cause the change of blasting time sequence and the overlapping of blast-holes. There are detonator dispersion phenomenon with the same delay time and superposition effect for seismic waves with different delay time, which brings great trouble to the value of charge weight per delay and the prediction of particle peak vibration velocity. In order to the predict particle peak vibration velocity more accurately and efficiently, the millisecond delay blasting test was conducted, and the calculation model of vibration velocity for group blast-hole simultaneous blasting with dispersed charge was established. The influence of the blast-hole number on the equivalent charge weight for simultaneous blasting and its value selection method were studied and constructed. The modified particle peak vibration velocity scaled distance formula and the particle peak vibration velocity prediction method were proposed based on the results of regression analysis of single-hole blasting. The results show that the equivalent charge weight of group blast-hole simultaneous blasting is smaller than the nominal charge weight per delay, and the equivalent charge weight of simultaneous blasting can be calculated by converting through the reduction coefficient, which decreases exponentially with the increase of the blast-hole number. The superposition effect of seismic waves with different delay time can be considered by introducing vibration wave superposition factor into the modified particle peak vibration velocity scaled distance formula. The average absolute error, average relative error and root mean square error between the actual and the predicted particle peak vibration velocity values are 0.05 cm/s, 9.52% and 0.059 cm/s, respectively. It is feasible to apply the modified particle peak vibration velocity proportional distance regression analysis method to the prediction and control of blasting vibration velocity in the field.

Aniba canelilla (Kunth) Mez essential oil-loaded nanoemulsion: Improved stability of the main constituents and in vitro antichemotactic activity

The essential oil extracted from Aniba canelilla (Kunth) Mez, an aromatic plant from the Amazon region, has 1-nitro-2-phenylethane and methyleugenol as major compounds and although presents historical evidence of treating topical disorders its incorporation in a formulation aiming topical administration was yet unexplored. In this sense, nanoemulsion containing essential oil of A. canelilla was produced by high pressure homogenization and characterized in terms of physicochemical parameters, morphology and thermo and photo (UVA and UVC) stabilities. In addition, in vitro antichemotactic activity was evaluated to the essential oil, isolated compounds and loaded nanoemulsion. The nanoemulsion showed nanometric droplet size with spherical shape, adequate size dispersion and negative charge. The nanoemulsion successfully protected the main compounds of A. canelilla essential oil from thermal degradation and volatilization, also protecting or delaying degradation against UVA and UVC light. The essential oil of A. canelilla, 1-nitro-2-phenylethane, methyleugenol and the nanoemulsion containing A. canelilla essential oil presented antichemotactic activity with reduction of polymorphonuclear neutrophils migration in the range of 24.1–100 %, suggesting an anti-inflammatory potential for these substances, mainly for the loaded nanoemulsion. These promising results revealed that the nanoemulsification of A. canelilla essential oil brought benefits as it maintained stability with an improvement of antichemotactic activity, suggesting it is an interesting strategy for topical delivery of 1-nitro-2-phenylethane and methyleugenol to treat inflamed skin.

Exploring the Interface Landscape of Noble Metals on Epitaxial Graphene

Understanding the interaction between noble metals (NMs) and epitaxial graphene is essential for the design and fabrication of novel devices. Within this framework, a combined experimental and theoretical investigation of the effect of vapor‐deposited NM (silver [Ag] and gold [Au]) nanostructures on the vibrational and electronic properties of monolayer epitaxial graphene (MLG) on 4H‐SiC is presented. Large sets of Raman scattering data are analyzed using supervised classification and statistical methods. This analysis enables identification of the specific Raman fingerprints of Au‐ and Ag‐decorated MLG originating from different dispersion interactions and charge transfer at the metal nanostructure/MLG interface. It is found that Raman scattering spectra of Au‐decorated MLG feature a set of allowed phonon modes similar to those in pristine MLG, whereas the stronger Ag physisorption triggers an activation of defect‐related phonon modes and electron doping of MLG. A principal component analysis (PCA) and linear discriminant analysis (LDA) are leveraged to highlight the features in phonon dispersion of MLG that emanate from the NM deposition process and to robustly classify large‐scale Raman spectra of metal‐decorated graphene. The present results can be advantageous for designing highly selective sensor arrays on MLG patches decorated with different metals.

New Cage-Like Cerium Trihydride Stabilized at Ambient Conditions

New Cage-Like Cerium Trihydride Stabilized at Ambient Conditions

Application of controlled blasting technology in mountain excavation under complex conditions

The blasting conditions of the site leveling project of a green power and renewable energy limited company are extremely complex. There are construction facilities on both sides of the excavated hill, and expressways and county roads on the front of the excavated hill. In order to control the impact of rolling stones, blasting vibration, blasting flying stones on surrounding buildings, bridges and culverts, pre-embedded industrial water pipes, highways and roadbeds during the excavation of mountain bodies, precise controlled blasting and comprehensive vibration reduction techniques such as weak loosening, controlling the maximum single-shot (single-segment) charge, hole-by-hole blasting, dispersed charge sectional blasting, axial spacing and radial uncoupled charge are proposed. Pre-splitting blasting technology is used to stabilize the slope in slope engineering and trench blasting technology is used in excavation of cut-off ditch. The technology guarantees the normal opening of the frontal expressway and county road during the excavation operation, and does not affect the safe production of the company. This technology guarantees that the excavation of mountain body will not affect the normal opening of frontal expressway and county road, and will not affect the safety of production of the company.

Radiation-Induced Transient Currents in Films of Poly(arylene ether ketone) Including Phthalide Moiety.

The electrical properties of thin films of poly(arylene ether ketone) copolymers (co-PAEKs) with a fraction of phthalide-containing units of 3, 5, and 50 mol% in the main chain were investigated by using radiation-induced conductivity (RIC) measurements. Transient current signals and current-voltage (I-V) characteristics were obtained by exposing 20 ÷ 25 μm thick films of the co-PAEKs to monoenergetic electron pulses with energy ranging from 3 to 50 keV in an electric field ranging from 5 to 40 V/μm. The Rose-Fowler-Vaisberg semi-empirical model based on a multiple trapping formalism was used for an analysis of the RIC data, and the parameters of the highly dispersive charge carrier transport were evaluated. The analysis revealed that charge carriers moved in isolation from each other, and the applied electric fields were below the threshold field triggering the switching effect (a reversible high-to-low resistivity transition) in the co-PAEK films. It was also found that the co-PAEK films, due to the super-linear I-V characteristics, are highly resistant to electrostatic discharges arising from the effects of ionizing radiation. This property is important for the development of protective coatings for electronic devices.

Dispersive sensing in hybrid InAs/Al nanowires

Dispersive charge sensing is realized in hybrid semiconductor-superconductor nanowires in gate-defined single- and double-island device geometries. Signal-to-noise ratios (SNRs) were measured in both the frequency and time domains. Frequency-domain measurements were carried out as a function of frequency and power and yield a charge sensitivity of 1 × 10–3 e/Hz for an ∼11 MHz measurement bandwidth. Time-domain measurements yield SNR > 1 for a 20 μs integration time. At zero magnetic field, photon-assisted tunneling was detected dispersively in a double-island geometry, indicating coherent hybridization of the two superconducting islands. At an axial magnetic field of 0.6 T, subgap states are detected dispersively, demonstrating the suitability of the method to sensing in the topological regime.

Технология взрывной отбойки крепких ценных руд при веерном расположении скважин

The ores of non-ferrous and precious metals, represented by hard rocks, has a peculiar feature, that is the effect of segregation, that is the tendency of ore minerals to break down into small size classes, which in the underground mining method accumulate in significant quantities on uneven surface of bottom layers and subsequently are lost. When mining valuable non-metallic materials, there is an acute problem of overgrinding, when fines do not meet the requirements for the quality of the final product. It is well known that the granulometric composition of the ore depends mainly on the technology and parameters of drilling and blasting operations. In underground mining of ore deposits, the main method of drilling and blasting is the borehole blasting with continuous construction charges with the ring pattern. The main drawbacks of the method are: uneven distribution of the explosive along the plane of the broken layer and the expenditure of a significant part of the blast energy of the charges of the continuous structure on the blasting effect, necessarily associated with over-grinding the ore. To solve these problems, the authors proposed a blasting technology, the essence of which lies in the fact that the uniform distribution of the energy concentration of explosives in the broken layer is ensured by the dispersion of charges by air gaps and a certain order of their placement in the ring plane. For the practical implementation of the technology, a method has been developed to form dispersed charges in deep boreholes that do not require a significant increase in labor costs and additional special means. A special technique has been created that allows defining the dispersion parameters, ensuring the sustained specific consumption of explosives over the entire plane of the broken layer. Experimental studies of the proposed technology in the natural conditions of an underground mine for the extraction of valuable granulated quartz were carried out. As a result, the possibility of a significant reduction in the specific consumption of explosives (by 42 %) has been established. At the same time, the yield of the commercial product increased by 10.7 % in total, and the yield of the fraction most favorable for further processing increased by 33.7 %.

The effect of translation on the binding energy for transition-metal porphyrines adsorbed on Ag(111) surface.

The characteristics of interaction between six transition-metal porphyrines and the Ag(111) surface are detailed here as resulted from DFT calculations. Van der Waals interactions as well as the strong correlation in 3d orbitals of transition metals were taken into account in all calculations, including the structural relaxation. For each system we investigate four relative positions of the metallic atom on top the surface. We show that the interaction between the transition metal and silver is the result of a combination between the dispersion interaction, charge transfer and weak chemical interaction. The detailed analysis of the physical properties, such as dipolar and magnetic moments and the molecule–surface charge transfer, analyzed for different geometric configurations allows us to propose qualitative models, relevant for the understanding of the self-assembly processes and related phenomena.

Tunable Coacervation of Well-Defined Homologous Polyanions and Polycations by Local Polarity.

The ionic complexation of polyelectrolytes is an important mechanism underlying many important biological processes and technical applications. The main driving force for complexation is electrostatic, which is known to be affected by the local polarity near charge centers, but the impact of which on the complexation of polyelectrolytes remains poorly explored. We developed a homologous series of well-defined polyelectrolytes with identical backbone structures, controlled molecular weights, and tunable local polarity to modulate the solvation environment near charged groups. A multitude of systematic, accurate phase diagrams were obtained by spectroscopic measurements of polymer concentrations via fluorescent labeling of polycations. These phase diagrams unambiguously revealed that the liquidlike coacervation is more stable against salt addition at reduced local polarity over a wide range of molecular weights. These trends were quantitatively captured by a theory of complexation that incorporates the effects of dispersion interactions, charge connectivity, and reversible ion-binding, providing the microscopic design rules for tuning molecular parameters and local polarity.

Glucose-Induced Formation of Oxygen Vacancy and Bi-Metal Comodified Bi5O7Br Nanotubes for Efficient Performance Photocatalysis

Here, we prepared Bi-metal modified defective Bi5O7Br nanotubes (Bi/Bi5O7Br–OV) by hydrothermal synthesis to be an efficient photocatalyst. Density function theory (DFT) revealed that oxygen vacancies in Bi5O7Br could form an intermediate level, which could allow electron transfer to a new intermediate level, and finally move to the conduction band. The Bi/Bi5O7Br–OV nanotubes demonstrate superior photocatalytic degradation of phenol, showing 3 times higher than that of pristine Bi5O7Br. The defects and Bi endow Bi5O7Br nanotubes with abundant active sites and improve the solar absorption. The increased and more dispersed charge density allow enhanced electronic conductivity and the separation of photogenerated carriers. Furthermore, more ·OH radicals are generated during photochemical reaction, which is beneficial in improving the photocatalytic performance. This work will play significant roles and create opportunities in modifying Bi-based materials for promoting photocatalysis.

Prediction of the electrical characteristics of heterostructural microwave devices with transverse current transfer based on a quantum-mechanical self-consistent model of a nanoscale channel with taking into account inter-valley scattering

A mathematical model of current transfer in AlGaAs- heterostructures with taking into account inter-valley dispersion and space charge in the process of degradation is presented. The developed computational algorithm is optimized by the criterion of temporal and spatial complexity. The relative deviation of the calculation results from the experimental data on the curvature of the initial portion of the current- voltage characteristic of the resonant tunnel diodes on AlGaAs- heterostructures is less than 3%.

Superweak Coordinating Anion as Superstrong Enhancer of Cyanine Organic Semiconductor Properties.

The superweak tetrakis(nonafluoro-tert-butoxy)aluminate coordinating anion was employed to introduce pseudo-gas-phase conditions to the 2-[5-(1,3-dihydro-1,3,3-trimethyl-2H-indol-2-ylidene)-1,3-pentadien-1-yl]-1,3,3-trimethyl-3H-indolium chromophore. The resulting formation of a photoactive organic-inorganic hybrid salt has led to a highly stabilized excited state of the organic chromophore mainly due to the minimized lattice energy and Coulomb interactions. These highly beneficial features caused by the well dispersed negative charge of the anion have led to an enhanced neat spin-casted film fluorescence intensity, prolonged fluorescence lifetime, smooth thin film surfaces and a record power photovoltaic efficiency of 3.8 % when compared to organic salts of this particular chromophore containing anions with localised negative charge. Clear evidence is given that a superweak coordinating anion is an emerging key parameter in cyanine dye photochemistry. This approach can be seen as a general guideline to prepare highly efficient ionic dyes for organic semiconductor applications.

Effect of different K:Na ratios in soil on dispersive charge, cation exchange and zeta potential

SummaryThe role of potassium (K) in clay dispersion in agricultural soils containing large concentrations of K could be similar to Na. This research was carried out to assess the effect of potassium to sodium ratios (K:Na) on net dispersive charge, Gapon selectivity coefficient (KG), zeta potential (ζ) and percentage of dispersible clay. Different K:Na ratios at two electrical conductivity levels (EC = 3 and 6 dS m−1) were added to an agricultural loamy soil. The results demonstrated that the net dispersive charge and percentage of dispersible clay showed positive relations with K concentration and K:Na ratio; also, the percentage of dispersible clay and net dispersive charge had a positive correlation, at both EC levels. Therefore, net dispersive charge as well as percentage of dispersible clay can show the degrading effect of K on soil structure. The KG values for K (KG(K)) were larger than those of Na (KG(Na)) because of large cation selectivity for K in soil. Neither KG(K) nor KG(Na) had a significant effect on the percentage of dispersible clay, but they did influence net dispersive charge, indicating that the status of cation exchange might affect dispersive charge of the soil. At both EC levels, absolute amounts of ζ, as an index of diffuse double layer (DDL) thickness, increased with increasing concentrations of monovalent cations (especially K). In addition, a strong positive correlation was observed between the dispersive charge and ζ. Our results demonstrated that K could affect soil structure because of a change in cation selectivity, with K increasing repulsive forces among clay particles and creating dispersion.Highlights K created repulsive forces between clay particles that led to clay dispersion. Net dispersive charge and dispersible clay increased with increasing K concentration and K:Na ratio. Cation exchange status (KG values) affected soil net dispersive charge significantly. A positive correlation between dispersive charge and zeta potential was observed.

Translation of metal-phthalocyanines adsorbed on Au(111): from van der Waals interaction to strong electronic correlation

Using first-principles calculations, we investigate the binding energy for six transition metal - phthalocyanine molecules adsorbed on Au(111). We focus on the effect of translation on molecule - surface physical properties; van der Waals interactions as well as the strong correlation in d orbitals of transition metals are taken into account in all calculations. We found that dispersion interaction and charge transfer have the dominant role in the molecule-surface interaction, while the interaction between the transition metal and gold has a rather indirect influence over the physics of the molecule-surface system. A detailed analysis of the physical properties of the adsorbates at different geometric configurations allows us to propose qualitative models to account for all values of interface dipole charge transfer and magnetic moment of metal-phthalocyanines adsorbed on Au(111).

Boron doping induced thermal conductivity enhancement of water-based 3C-Si(B)C nanofluids

In this paper, the fabrication and thermal conductivity (TC) of water-based nanofluids using boron (B)-doped SiC as dispersions are reported. Doping B into the β-SiC phase leads to the shrinkage of the SiC lattice due to the substitution of Si atoms (0.134 nm radius) by smaller B atoms (0.095 nm radius). The presence of B in the SiC phase also promotes crystallization and grain growth of obtained particles. The tailored crystal structure and morphology of B-doped SiC nanoparticles are beneficial for the TC improvement of the nanofluids by using them as dispersions. Using B-doped SiC nanoparticles as dispersions for nanofluids, a remarkable improvement in stability was achieved in SiC-B6 nanofluid at pH 11 by means of the Zeta potential measurement. By dispersing B-doped SiC nanoparticles in water-based fluids, the TC of the as-prepared nanofluids containing only 0.3 vol.% SiC-B6 nanoparticles is remarkably raised to 39.3% at 30 °C compared to the base fluids, and is further enhanced with the increased temperature. The main reasons for the improvement in TC of SiC-B6 nanofluids are more stable dispersion and intensive charge ions vibration around the surface of nanoparticles as well as the enhanced TC of the SiC-B dispersions.

Solvent Effect on the Potential Energy Surfaces of the F- + CH3CH2Br Reaction.

Although substantial work has been undertaken on reaction pathways involved in base-promoted elimination reactions and bimolecular nucleophilic substitution reaction of F- on CH3CH2X (X = Cl, Br, I), the effect of solvents with varying dielectric constants on the stereochemistry of each of the reaction species involved across the reaction profile have not yet been clearly understood. The present investigation reports the effect of solvents on the potential energy surfaces (PES) and structures of the species appearing in the reaction pathway of F- with bromoethane. The PESs in the gas phase have been computed at MP2 level and CCSD(T) level. The performance of several hybrid density functional, such as B3LYP, M06, M06L, BHandH, X3LYP, M05, M05-2X, and M06-2X have also been investigated toward describing the elimination and nucleophilic substitution reactions. With respect to MAE values and to make the computation cost-effective, we have explored the implicit continuum solvent model, CPCM in solvents like cyclohexane, methanol, acetonitrile, dimethyl sulfoxide and water. The reactant complexes proceed through the subsequent steps to produce fluoroethane as the substitution product and ethylene as one of the elimination products. For elimination reaction both syn and anti elimination have been explored. The calculated relatives energies values, which are negative in the gas phase, are found to be positive in polar solvents since the point charge in the separated reactants are more stabilized than the dispersed charge in the transient complex, which has also been analyzed through NBO analysis.