Bifurcations and exact solutions of an asymptotic rotation-Camassa–Holm equation

This paper investigates the rotation-Camassa–Holm equation, which appears in long-crested shallow-water waves propagating in the equatorial ocean regions with the Coriolis effect due to the earth’s rotation. The rotation-Camassa–Holm equation contains the famous Camassa–Holm equation and is a special case of the generalized Camassa–Holm equation. By using the approach of dynamical systems and singular traveling wave theory to its traveling wave system, in different parameter conditions of the five-parameter space, the bifurcations of phase portraits are studied. Some exact explicit parametric representations of the smooth solitary wave solutions, periodic wave solutions, peakons and anti-peakons, periodic peakons as well as compacton solutions are obtained.

     

Iridium Complex of N-Fused Bilatrienone: Oxidative Cleavage of N-Fused Porphyrin Induced by Iridium-Cyclooctadiene Complexation

N-fused porphyrin (NFP) is a unique class of photostable near-infrared dyes with an 18π aromatic tetrapyrrole macrocyclic skeleton containing a tri-fused pentacyclic moiety. Here, the synthesis of an iridium complex of N-fused bilatrienone is reported as the degradation product of Ir-cyclooctadiene (cod)-induced oxidative cleavage of NFP under aerobic conditions. Similar to the native bilin chromophores, the ring-opened complex featured a broken π-conjugation circuit and exhibited a broad visible absorption band. In contrast, metalation of NFP using an iridium(I)(cod) complex under an inert atmosphere resulted in the formation of a cod-isomerized (κ¹,η³-C₈H₁₂)-Ir complex.     

Anisotropic longitudinal electron diffusion coefficient in wurtzite gallium nitride

The longitudinal electron diffusion coefficient (D _l ) of wurtzite (WZ) gallium nitride (GaN) is calculated by an ensemble Monte Carlo (EMC) method. By using the power spectral density associated with velocity fluctuation, the relationship between D _l and electric field strength, frequency, doping concentration and temperature is presented. The anisotropic D _l of GaN impacted by anisotropy of the electronic dispersion is also investigated. It has been found that the D _l in Γ–A direction (c-direction) is larger than that in Γ–M direction (basal plane) in most cases. For lower electric field, the D _l keeps constant at first, then decreases with increasing frequency. However, for higher electric field, the D _l firstly approaches a peak value, then decreases with increasing frequency. When the frequency is zero, the D _l decreases with the increasing electric field, and then increases until a peak value. Finally, it decreases with increasing electric field again. When the temperature increases, the D _l decreases in both directions for increasing scattering rate. A comparison between our calculated diffusion coefficient and the mobility under low electric field by Einstein equation is presented.     

Bifurcations and parametric representations of traveling wave solutions for the (2+1)‐dimensional Boiti–Leon–Pempinelle system

By using the method of bifurcation theory of planar dynamical systems to the traveling wave system of the (2+1)‐dimensional Boiti–Leon–Pempinelle system, exact explicit parametric representations of the traveling wave solutions are obtained in different parameter regions. Copyright © 2010 John Wiley & Sons, Ltd.     

Exact traveling wave solutions for the Benjamin–Bona–Mahony equation by improved Fan sub-equation method

This paper combines the bifurcation theory of dynamical systems and the Fan sub-equation method to improve the Fan sub-equation method for solving the BBM equation. Periodic solutions, kink solutions and solitary solutions are formally derived in a general form. This method is straightforward and concise, and it can also be applied to other nonlinear evolution equations.     

Slow light in photonic crystals waveguide constructed with symmetrically perturbed structure

Symmetrically perturbed photonic crystal waveguide can be constructed by inserting perturbative dielectric rods into photonic crystal waveguide structure with whose rods’ radius distributed according to a certain proportion. Slow light properties in this new structure are studied by using the plane wave expansion method (PWM). In this paper, schemes of adjusting radius of perturbative dielectric rods and adjusting the dielectric constant of perturbative dielectric rods are proposed to optimize slow light properties. The result shows that the scheme for adjusting radius of perturbative rods can realize larger average slow light bandwidth and efficiently control the NDBP value of the waveguide, but it contributes little to obtain smaller group velocity. The scheme for adjusting dielectric constant of perturbative rods can realize smaller group velocity, but can only obtain smaller slow light bandwidth and cannot efficiently enlarge NDBP value of waveguide. Both optimization schemes proposed in this paper realize group velocity that is two magnitudes smaller than the vacuum speed of light meanwhile maintaining large NDBP and low GVD region. Our results provide important theoretical basis for the potential application offered by symmetrically perturbed photonic crystal in future optical networks.     

Handover method in visible light communication between the moving vehicle and multiple LED streetlights

When the moving vehicle is communicating with LED streetlights by visible light, the multiple LED streetlights signals will be selected or signal may be interrupted between adjacent streetlights. The method of receiving signal power (RSP) handover between the moving vehicle and multiple LED streetlights transmitters will be studied. Considering two cases, no power coverage and power overlap between adjacent streetlights. Hard RSP handover used in no power coverage model and soft RSP handover used in power overlap model. Simulation results show both RSP handover methods can protect the communication between the vehicle and LED streetlights and improve the stability of communication.     

An Ultrasound Activated Vesicle of Janus Au-MnO Nanoparticles for Promoted Tumor Penetration and Sono-Chemodynamic Therapy of Orthotopic Liver Cancer

Sonodynamic therapy (SDT) has the advantages of high penetration, non-invasiveness, and controllability, and it is suitable for deep-seated tumors. However, there is still a lack of effective sonosensitizers with high sensitivity, safety, and penetration. Now, ultrasound (US) and glutathione (GSH) dual responsive vesicles of Janus Au-MnO nanoparticles (JNPs) were coated with PEG and a ROS-sensitive polymer. Upon US irradiation, the vesicles were disassembled into small Janus Au-MnO nanoparticles (NPs) with promoted penetration ability. Subsequently, GSH-triggered MnO degradation simultaneously released smaller Au NPs as numerous cavitation nucleation sites and Mn²⁺ for chemodynamic therapy (CDT), resulting in enhanced reactive oxygen species (ROS) generation. This also allowed dual-modality photoacoustic imaging in the second near-infrared (NIR) window and T₁-MR imaging due to the released Mn²⁺, and inhibited orthotopic liver tumor growth via synergistic SDT/CDT.     

Ag+-Coupled Black Phosphorus Vesicles with Emerging NIR-II Photoacoustic Imaging Performance for Cancer Immune-Dynamic Therapy and Fast Wound Healing

A silver-ion-coupled black phosphorus (BP) vesicle (BP Ve-Ag⁺) with a second near infrared (NIR-II) window photoacoustic (PA) imaging capability was firstly constructed to maximize the potential of BP quantum dot (QD) in deeper bioimaging and diversified therapy. The embedded Ag⁺ could improve the relatively large band gap of BP QD via intense charge coupling based on theoretical simulation results, subsequently leading to the enhanced optical absorption capability, accompanied with the occurrence of the strong NIR-II PA signal. Guiding by NIR-II PA bioimaging, the hidden Ag⁺ could be precisely released with the disassembly of Ve during photodynamic therapy process and captured by macrophages located in lesion region for arousing synergistic cancer photodynamic/Ag⁺ immunotherapy. BP Ve-Ag⁺ can contrapuntally kill pathogenic bacteria and accelerate wound healing monitored by NIR-II PA imaging.     

Study of Surface Modification of Nanosize Si3N4 with Macromolecular Coupling Agent LMPB-g-GMA in Different Solvents

A new macromolecular coupling agent, low-molecular-weight polybutadiene liquid rubber (LMPB)-glycidyl methacrylate (GMA), was synthesized using solution polymerization initiated by benzoyl peroxide (BPO). The molecular structure was confirmed by FTIR and NMR. This macromolecular LMPB-GMA was used for surface modification of silicon nitride (Si₃N₄) nanopowder in n-heptane, chloroform, ethyl acetate, and DMF, respectively. LMPB-GMA and modified nano-Si₃N₄ were systematically investigated by FTIR, NMR, TGA, and TEM. The results showed that LMPB-GMA bonded and formed an organic coating layer onto the surface of nanosized Si₃N₄ particles. The polarity of the solvents plays an important role in this process. Strong or weak polar both affect the results. The dosage loading of LMPB-GMA is 12 wt% of nanosized Si₃N₄. Nanosized Si₃N₄ modified in ethyl acetate has better dispersibility and stability than that modified in n-heptane or DMF. TEM pictures also reveal that modified nano-Si₃N₄ possesses good dispersibility.