Small data global regularity for simplified 3-D Ericksen-Leslie's compressible hyperbolic liquid crystal model

In this article, we consider the Ericksen-Leslie's hyperbolic system for compressible liquid crystal model in three spatial dimensions. Global regularity for small and smooth initial data near equilibrium is proved for the case that the system is a nonlinear coupling of compressible Navier-Stokes equations with wave map to $\mathbb{S}^2$. Our argument is a combination of vector field method and Fourier analysis. The main strategy to prove global regularity relies on an interplay between the control of high order energies and decay estimates, which is based on the idea inspired by the method of space-time resonances. In particular the different behaviors of the decay properties of the density and velocity field for compressible fluids at different frequencies play a key role.Comment: 61 pages; all comments wellcom

Constraints on holographic dark energy models using the differential ages of passively evolving galaxies

Using the absolute ages of passively evolving galaxies observed at different redshifts, one can obtain the differential ages, the derivative of redshift $z$ with respect to the cosmic time $t$ (i.e. ${\rm d} z/{\rm d}t$). Thus, the Hubble parameter $H(z)$ can be measured through the relation $H(z)=-({\rm d} z/{\rm d}t)/(1+z)$. By comparing the measured Hubble parameter at different redshifts with the theoretical one containing free cosmological parameters, one can constrain current cosmological models. In this paper, we use this method to present the constraint on a spatially flat Friedman-Robert-Walker Universe with a matter component and a holographic dark energy component, in which the parameter $c$ plays a significant role in this dark energy model. Firstly we consider three fixed values of $c$=0.6, 1.0 and 1.4 in the fitting of data. If we set $c$ free, the best fitting values are $c=0.26$, $\Omega_{\rm m0}=0.16$, $h=0.9998$. It is shown that the holographic dark energy behaves like a quintom-type at the $1\sigma$ level. This result is consistent with some other independent cosmological constrains, which imply that $c<1.0$ is favored. We also test the results derived from the differential ages using another independent method based on the lookback time to galaxy clusters and the age of the universe. It shows that our results are reliable.Comment: 18 pages including 7 figures and 1 tables. Final version for publication in Modern Physics Letters A (MPLA)[minor revision to match the appear version

Dual-band filtering power divider with capacitor-loaded centrally coupled-line resonators

In this paper, a dual-band filtering power divider (DB-FPD) with capacitor-loaded centrally coupled-line resonators (CLCCLRs) is presented. The proposed design utilizes four CLCCLRs, two resistors and one inductor to achieve the dual functions of dual-band filtering and power division. By altering the values of the capacitors loaded at the ends of the coupled-lines, the center frequencies of the two passbands can be adjusted independently. It is noted that changing one passband will not affect the other. For demonstration, a microstrip filtering power divider is designed, fabricated and measured. Under different values of the loaded capacitors, experimental results show that the lower band center frequency varies from 0.7 GHz to 1.0 GHz with the upper band fixed at 1.75 GHz, whereas the upper band center frequency varies from 1.65 GHz to 1.95 GHz when the lower band is fixed at 1.0 GHz. The measured results show good agreement with the simulations

PlantPAN: Plant promoter analysis navigator, for identifying combinatorial cis-regulatory elements with distance constraint in plant gene groups

<p>Abstract</p> <p>Background</p> <p>The elucidation of transcriptional regulation in plant genes is important area of research for plant scientists, following the mapping of various plant genomes, such as <it>A. thaliana</it>, <it>O. sativa </it>and <it>Z. mays</it>. A variety of bioinformatic servers or databases of plant promoters have been established, although most have been focused only on annotating transcription factor binding sites in a single gene and have neglected some important regulatory elements (tandem repeats and CpG/CpNpG islands) in promoter regions. Additionally, the combinatorial interaction of transcription factors (TFs) is important in regulating the gene group that is associated with the same expression pattern. Therefore, a tool for detecting the co-regulation of transcription factors in a group of gene promoters is required.</p> <p>Results</p> <p>This study develops a database-assisted system, PlantPAN (Plant Promoter Analysis Navigator), for recognizing combinatorial <it>cis</it>-regulatory elements with a distance constraint in sets of plant genes. The system collects the plant transcription factor binding profiles from PLACE, TRANSFAC (public release 7.0), AGRIS, and JASPER databases and allows users to input a group of gene IDs or promoter sequences, enabling the co-occurrence of combinatorial transcription factor binding sites (TFBSs) within a defined distance (20 bp to 200 bp) to be identified. Furthermore, the new resource enables other regulatory features in a plant promoter, such as CpG/CpNpG islands and tandem repeats, to be displayed. The regulatory elements in the conserved regions of the promoters across homologous genes are detected and presented.</p> <p>Conclusion</p> <p>In addition to providing a user-friendly input/output interface, PlantPAN has numerous advantages in the analysis of a plant promoter. Several case studies have established the effectiveness of PlantPAN. This novel analytical resource is now freely available at <url>http://PlantPAN.mbc.nctu.edu.tw</url>.</p

Surface Chern-Simons theory for third-order topological insulators and superconductors

Three-dimensional 3rd-order topological insulators (TOTIs) and superconductors (TOTSCs), as the highestorder topological phases hosting zero corner modes in physical dimension, has sparked extensive research interest. However, such topological states have not been discovered in reality due to the lack of experimental schemes of realization. Here, we propose a novel surface Chern-Simons (CS) theory for 3rd-order topological phases, and show that the theory enables a feasible and systematic design of TOTIs and TOTSCs. We show that the emergence of zero Dirac (Majorana) corner modes is entirely captured by an emergent $\mathbb{Z}_{2}$ CS term that can be further characterized by a novel two-particle Wess-Zumino (WZ) term uncovered here in the surfaces of three-dimensional topological materials. Importantly, our proposed CS term characterization and two-particle WZ term mechanism provide a unique perspective to design TOTIs (TOTSCs) in terms of minimal ingredients, feasibly guiding the search for underlying materials, with promising candidates being discussed. This work shall advance both the theoretical and experimental research for highest-order topological matters.Comment: 5+11 pages, 4+5 figure

Wireless Power Transfer and Energy Harvesting Using Metamaterials and Metasurfaces

In this invited talk/paper, we review and explore the use of metamaterials and metasurfaces for wireless power transfer (WPT) and wireless energy harvesting (WEH) which are two closely related hot topics. The focus is on how to improve the energy conversion efficiency of both systems. It is shown that metamaterials and metasurfaces can indeed achieve a higher RF to DC energy conversion efficiency and operational distance by changing the electromagnetic fields between the transmitter and receiver, and/or making their reception less sensitive to incident wave angle and polarization. They can also be used as either parasitic elements or loading components to improve WEH performance

Poly[(μ5-2,6-dimethyl­pyridine-3,5-dicarboxyl­ato)zinc]

In the polymeric title complex, [Zn(C9H7NO4)]n, the ZnII cation is located on a twofold rotation axis and is coordinated by five 2,6-dimethyl­pyridine-3,5-dicarboxyl­ate (mpdc) anions in a distorted ZnNO4 trigonal–bipyramidal geometry. The mpdc anion is also located on the twofold rotation axis and bridges five ZnII cations, forming the three-dimensional polymeric complex. Weak C—H⋯π inter­actions are present in the crystal structure

P3^3OVD: Fine-grained Visual-Text Prompt-Driven Self-Training for Open-Vocabulary Object Detection

Inspired by the success of visual-language methods (VLMs) in zero-shot classification, recent works attempt to extend this line of work into object detection by leveraging the localization ability of pre-trained VLMs and generating pseudo labels for unseen classes in a self-training manner. However, since the current VLMs are usually pre-trained with aligning sentence embedding with global image embedding, the direct use of them lacks fine-grained alignment for object instances, which is the core of detection. In this paper, we propose a simple but effective Pretrain-adaPt-Pseudo labeling paradigm for Open-Vocabulary Detection (P$^3$OVD) that introduces a fine-grained visual-text prompt adapting stage to enhance the current self-training paradigm with a more powerful fine-grained alignment. During the adapting stage, we enable VLM to obtain fine-grained alignment by using learnable text prompts to resolve an auxiliary dense pixel-wise prediction task. Furthermore, we propose a visual prompt module to provide the prior task information (i.e., the categories need to be predicted) for the vision branch to better adapt the pretrained VLM to the downstream tasks. Experiments show that our method achieves the state-of-the-art performance for open-vocabulary object detection, e.g., 31.5% mAP on unseen classes of COCO