Design of Ultra-compact Graphene-based Superscatterers

The energy-momentum dispersion relation is a fundamental property of plasmonic systems. In this paper, we show that the method of dispersion engineering can be used for the design of ultra-compact graphene-based superscatterers. Based on the Bohr model, the dispersion relation of the equivalent planar waveguide is engineered to enhance the scattering cross section of a dielectric cylinder. Bohr conditions with different orders are fulfilled in multiple dispersion curves at the same resonant frequency. Thus the resonance peaks from the first and second order scattering terms are overlapped in the deepsubwavelength scale by delicately tuning the gap thickness between two graphene layers. Using this ultra-compact graphene-based superscatterer, the scattering cross section of the dielectric cylinder can be enhanced by five orders of magnitude.Comment: This paper has been accepted by IEEE Journal of Selected topics in Quantum Electronic

Histone H4 H75E mutation attenuates global genomic and Rad26-independent transcription-coupled nucleotide excision repair

Nucleotide excision repair (NER) consists of global genomic NER (GG-NER) and transcription coupled NER (TC-NER) subpathways. In eukaryotic cells, genomic DNA is wrapped around histone octamers (an H3-H4 tetramer and two H2A-H2B dimers) to form nucleosomes, which are well known to profoundly inhibit the access of NER proteins. Through unbiased screening of histone H4 residues in the nucleosomal LRS (loss of ribosomal DNA-silencing) domain, we identified 24 mutations that enhance or decrease UV sensitivity of Saccharomyces cerevisiae cells. The histone H4 H75E mutation, which is largely embedded in the nucleosome and interacts with histone H2B, significantly attenuates GG-NER and Rad26-independent TC-NER but does not affect TC-NER in the presence of Rad26. All the other histone H4 mutations, except for T73F and T73Y that mildly attenuate GG-NER, do not substantially affect GG-NER or TC-NER. The attenuation of GG-NER and Rad26-independent TC-NER by the H4H75E mutation is not due to decreased chromatin accessibility, impaired methylation of histone H3 K79 that is at the center of the LRS domain, or lowered expression of NER proteins. Instead, the attenuation is at least in part due to impaired recruitment of Rad4, the key lesion recognition and verification protein, to chromatin following induction of DNA lesions

Outer characteristic simulation and performance analysis of variable shock absorber

In this study, a variable shock absorber (VSA) for semi-active suspension is developed, the structure and operation principle of the VSA is illustrated. Based on the theory of hydraulics and elasticity, the ways of calculating for the embranchment flow rate and the throttle pressure difference on the series-parallel complex pipe line (SPCPL) are deduced and employed, and the detailed mathematical model of the VSA is established by using the differential equation for annular laminar deformation under uniform load (ALDUUL). The MATLAB/Simulink software is used to simulate the detailed model, and the calculated results agree well with the experimental results. In particular, the influence rules of the bypass groove diameter of the VSA on its damping is analyzed through this model, and the results obtained can technically support the design and performance prediction of the VSA to a certain degree