Gauge Field Induced Chiral Zero Mode in Five-dimensional Yang Monopole Metamaterials

Owing to the chirality of Weyl nodes characterized by the first Chern number, a Weyl system supports one-way chiral zero modes under a magnetic field, which underlies the celebrated chiral anomaly. As a generalization of Weyl nodes from three-dimensional to five-dimensional physical systems, Yang monopoles are topological singularities carrying nonzero second-order Chern numbers c2 = +1 or -1. Here, we couple a Yang monopole with an external gauge field using an inhomogeneous Yang monopole metamaterial, and experimentally demonstrate the existence of a gapless chiral zero mode, where the judiciously designed metallic helical structures and the corresponding effective antisymmetric bianisotropic terms provide the means for controlling gauge fields in a synthetic five-dimensional space. This zeroth mode is found to originate from the coupling between the second Chern singularity and a generalized 4-form gauge field - the wedge product of the magnetic field with itself. This generalization reveals intrinsic connections between physical systems of different dimensions, while a higher dimensional system exhibits much richer supersymmetric structures in Landau level degeneracy due to the internal degrees of freedom. Our study offers the possibility of controlling electromagnetic waves by leveraging the concept of higher-order and higher-dimensional topological phenomena.Comment: 64 pages including supplementary material, to appear in Physical Review Letter

Dendrimer-Based Demulsifiers for Polymer Flooding Oil-in-Water Emulsions

Two polyamidoamine-based dendritic molecules, named here as benzyl-G3 and octyl-G3, were synthesized using H₂NCH₂CH₂NRCH₂CH₂NH₂ (where R is either rigid benzyl or flexible octyl hydrophobic tails that are linked to the central nitrogen atom). With consideration of factors, such as the settling time, demulsifier dosage, temperature, oil content, and kinds of surfactants, the synthesized molecules were systematically investigated as demulsifiers for breaking up polymer flooding oil-in-water emulsions. In comparison to traditional G3 polyamidoamine, both benzyl-G3 and octyl-G3 exhibited better demulsification efficiencies with a dosage of 200 mg/L at a relatively low temperature (30 °C) in short periods of time (40 min) and reached 99.3 and 99.8% oil removal rates as they were added to the low oil-containing emulsion (1500 mg/L), respectively. A series of measurement methods were then adopted to explore the demulsification mechanism of the two demulsifiers. The interfacial tension and ζ potential measurements indicated that the high demulsification efficiency of the two dendrimers could be due to electrostatic charge neutralization. Moreover, the dendrimers and surfactants showed strong interactions according to the turbidity measurements, the results of which demonstrated that the hydrophobic tails located at the center of the dendrimers also influenced the demulsification efficiency

The Demulsification Properties of Cationic Hyperbranched Polyamidoamines for Polymer Flooding Emulsions and Microemulsions

Polymer flooding emulsions and microemulsions caused by tertiary oil recovery technologies are harmful to the environment due to their excellent stability. Two cationic hyperbranched polyamidoamines (H-PAMAM), named as H-PAMAM-HA and H-PAMAM-ETA, were obtained by changing the terminal denotation agents to H-PAMAM, which was characterized by 1H NMR, FT-IR, and amine possession, thereby confirmed the modification. Samples (300 mg/L) were added to the polymer flooding emulsion (1500 mg/L oil concentration) at 30 °C for 30 min and the H-PAMAM-HA and H-PAMAM-ETA were shown to perform at 88% and 91% deoil efficiency. Additionally, the increased settling time and the raised temperature enhanced performance. For example, an oil removal ratio of 97.7% was observed after dealing with the emulsion for 30 min at 60 °C, while 98.5% deoil efficiency was obtained after 90 min at 45 °C for the 300 mg/L H-PAMAM-ETA. To determine the differences when dealing with the emulsion, the interfacial tension, ζ potential, and turbidity measurements were fully estimated. Moreover, diametrically different demulsification mechanisms were found when the samples were utilized to treat the microemulsion. The modified demulsifiers showed excellent demulsification efficiency via their obvious electroneutralization and bridge functions, while the H-PAMAM appeared to enhance the stability of the microemulsion

Nitrogen-Rich Salts Based on the Energetic [Monoaquabis(<i>N</i>,<i>N</i>‑bis(1<i>H</i>‑tetrazol-5-yl)amine)-zinc(II)] Anion: A Promising Design in the Development of New Energetic Materials

Nitrogen-rich energetic salts involving various cations (lithium, <b>1</b>; ammonium, <b>2</b>; hydrazinium, <b>3</b>; hydroxylammonium, <b>4</b>; guanidinium, <b>5</b>; aminoguanidinium, <b>6</b>; diaminoguanidinium, <b>7</b>; and triaminoguanidinium, <b>8</b>) based on nitrogen-rich anion [Zn­(BTA)₂(H₂O)]^2– (N% = 65.37, BTA = <i>N</i>,<i>N</i>-bis­[1<i>H</i>-tetrazol-5-yl]­amine anion) were synthesized with a simple method. The crystal structures of all compounds except <b>1</b>, <b>2</b>, and <b>6</b> were determined by single-crystal X-ray diffraction and fully characterized by elemental analysis and FT-IR spectroscopy. The thermal stabilities were investigated by differential scanning calorimetry (DSC). The DSC results show that all compounds exhibit high thermal stabilities (decomposition temperature >200 °C). Additionally, the heats of formation were calculated on the basis of the experimental constant-volume energies of combustion measured by using bomb calorimetry. Lastly, the sensitivities toward impact and friction were assessed according to Bundesamt für Materialforschung (BAM) standard methods

Nitrogen-Rich Salts Based on the Energetic [Monoaquabis(<i>N</i>,<i>N</i>‑bis(1<i>H</i>‑tetrazol-5-yl)amine)-zinc(II)] Anion: A Promising Design in the Development of New Energetic Materials

Nitrogen-rich energetic salts involving various cations (lithium, <b>1</b>; ammonium, <b>2</b>; hydrazinium, <b>3</b>; hydroxylammonium, <b>4</b>; guanidinium, <b>5</b>; aminoguanidinium, <b>6</b>; diaminoguanidinium, <b>7</b>; and triaminoguanidinium, <b>8</b>) based on nitrogen-rich anion [Zn­(BTA)₂(H₂O)]^2– (N% = 65.37, BTA = <i>N</i>,<i>N</i>-bis­[1<i>H</i>-tetrazol-5-yl]­amine anion) were synthesized with a simple method. The crystal structures of all compounds except <b>1</b>, <b>2</b>, and <b>6</b> were determined by single-crystal X-ray diffraction and fully characterized by elemental analysis and FT-IR spectroscopy. The thermal stabilities were investigated by differential scanning calorimetry (DSC). The DSC results show that all compounds exhibit high thermal stabilities (decomposition temperature >200 °C). Additionally, the heats of formation were calculated on the basis of the experimental constant-volume energies of combustion measured by using bomb calorimetry. Lastly, the sensitivities toward impact and friction were assessed according to Bundesamt für Materialforschung (BAM) standard methods