Formation Mechanism of Well-Ordered Densely Packed Nanoparticle Superlattices Deposited from Gas Phase on Template-Free Surfaces

Superlattices of nanoparticles are generally produced based on solution chemistry processes. In this paper, we demonstrate that self-assembled monolayer structures of nanoparticles with superlattice periodicities can also be produced on template-free surfaces in the gas-phase cluster beam deposition process. It is found that the packing of Fe nanoparticles corresponds to an average of two-dimensional densely packed lattice with a hexagonal summary. By controlling the nanoparticle coverage, the two-dimensional densely packed monolayer morphology can spread to the whole substrate surface being deposited. A formation mechanism of the ordered monolayers is proposed. The densely packed morphologies are formed by the balance between the diffusion rate of the nanoparticles and their filling speed on the substrate surface determined by the deposition rate, and the ordering of the nanoparticle arrays is driven by the inter-particle attractive interactions. The model is strongly supported by a series of carefully designed cluster deposition experiments.

Formation Mechanism of Well-Ordered Densely Packed Nanoparticle Superlattices Deposited from Gas Phase on Template-Free Surfaces

Superlattices of nanoparticles are generally produced based on solution chemistry processes. In this paper, we demonstrate that self-assembled monolayer structures of nanoparticles with superlattice periodicities can also be produced on template-free surfaces in the gas phase cluster beam deposition process. It is found the packing of Fe nanoparticles corresponds to an average two-dimensional densely-packed lattice with a hexagonal summary. By controlling the nanoparticle coverage, the two-dimensional densely-packed monolayer morphology can spread to the whole substrate surface being deposited. A formation mechanism of the ordered monolayers is proposed by considering the balance between the diffusion rate of the nanoparticles and their filling speed on the substrate surface determined by the deposition rate, and the ordering driven by the inter-particle attractive forces. The model is strongly supported by a serial of carefully designed cluster deposition experiments.

Phase coexistence in fluidization

The coexistence of granular liquid-like phase (cluster) and gas-like phase (void) in fluidization, a spontaneous symmetry-breaking dissipative state, contributes to excellent mixing behavior in multi-phase reactors. In present study, a universal granular state equation to describe phase coexistence far from critical point is developed, where both the inelastic solid-collision and asymmetrical instability is taken into consideration. Catastrophe theory is applied to find the stable boundary of phase coexistence, and verified by cold-flow experiment with different solid pressure. A phase diagram, based on both theoretical analysis and experimental study, is given as a useful guideline of design and operation of efficient multi-phase reactors.

A NEXUS BETWEEN HOUSEHOLD CHARACTERISTICS AND WOMEN’S EMPOWERMENT: A CASE STUDY OF PUNJAB, PAKISTAN

Purpose of the study: The empowerment of women is an important aim for them to be fully engaged in economic life and to achieve sustainable growth worldwide. One form of empowerment is to provide women with basic facilities. Methodology: The study also analyzed the impact on women's empowerment by primary data taken via multi-phase cluster sampling methods of household socio-economic and cultural characteristics in Punjab. Given the diversity of nature and context, the 6-dimensional empirical polychoric principles of empowering women generate a stringent cumulative index of women's autonomy. Main Findings: The empirical findings show that empowering women and their six-dimensional effects are positive for women's years and jobs, legal advertisements, health care institutions, social participation, safe, smooth surroundings, communication, politics and residential negative participation, unpaid housekeeping, and the fear of violence. The results show that women's empowerment is positive. Applications of this study: This study can be more effective in the manner that to offer women free advice about their rights through electronic media, the government should establish an integrated legal cell with the local government. Novelty/Originality of this study: This research contribution in the field of women empowerment that how women can deal with legal advisory, to get jobs, protection in health and institutions.

Consecutive Methane Activation Mediated by Single Metal Boride Cluster Anions NbB4−

Cleavage all C−H bonds in two methane molecules by gas-phase cluster ions at room temperature is a challenging task. Herein, mass spectrometry and quantum chemical calculations have been used to...

The Necessity of Periodic Boundary Conditions for the Accurate Calculation of Crystalline Terahertz Spectra

Terahertz vibrational spectroscopy has emerged as a powerful spectroscopic technique, providing valuable information regarding long-range interactions -- and associated collective dynamics -- occurring in solids. However, the terahertz sciences are relatively nascent, and there have been significant advances over the last several decades that have profoundly influenced the interpretation and assignment of experimental terahertz spectra. Specifically, because there do not exist any functional group or material-specific terahertz transitions, it is not possible to interpret experimental spectra without additional analysis, specifically, computational simulations. Over the years simulations utilizing periodic boundary conditions have proven to be most successful for reproducing experimental terahertz dynamics, due to the ability of the calculations to accurately take long-range forces into account. On the other hand, there are numerous reports in the literature that utilize gas phase cluster geometries, to varying levels of apparent success. This perspective will provide a concise introduction into the terahertz sciences, specifically terahertz spectroscopy, followed by an evaluation of gas phase and periodic simulations for the assignment of crystalline terahertz spectra, highlighting potential pitfalls and good practice for future endeavors.

The Necessity of Periodic Boundary Conditions for the Accurate Calculation of Crystalline Terahertz Spectra

Terahertz vibrational spectroscopy has emerged as a powerful spectroscopic technique, providing valuable information regarding long-range interactions -- and associated collective dynamics -- occurring in solids. However, the terahertz sciences are relatively nascent, and there have been significant advances over the last several decades that have profoundly influenced the interpretation and assignment of experimental terahertz spectra. Specifically, because there do not exist any functional group or material-specific terahertz transitions, it is not possible to interpret experimental spectra without additional analysis, specifically, computational simulations. Over the years simulations utilizing periodic boundary conditions have proven to be most successful for reproducing experimental terahertz dynamics, due to the ability of the calculations to accurately take long-range forces into account. On the other hand, there are numerous reports in the literature that utilize gas phase cluster geometries, to varying levels of apparent success. This perspective will provide a concise introduction into the terahertz sciences, specifically terahertz spectroscopy, followed by an evaluation of gas phase and periodic simulations for the assignment of crystalline terahertz spectra, highlighting potential pitfalls and good practice for future endeavors.