Terminal Sliding Mode Control of Mobile Wheeled Inverted Pendulum System with Nonlinear Disturbance Observer

A terminal sliding mode controller with nonlinear disturbance observer is investigated to control mobile wheeled inverted pendulum system. In order to eliminate the main drawback of the sliding mode control, “chattering” phenomenon, and for compensation of the model uncertainties and external disturbance, we designed a nonlinear disturbance observer of the mobile wheeled inverted pendulum system. Based on the nonlinear disturbance observer, a terminal sliding mode controller is also proposed. The stability of the closed-loop mobile wheeled inverted pendulum system is proved by Lyapunov theorem. Simulation results show that the terminal sliding mode controller with nonlinear disturbance observer can eliminate the “chattering” phenomenon, improve the control precision, and suppress the effects of external disturbance and model uncertainties effectively

Estrogen-Dependent Epigenetic Regulation of Soluble Epoxide Hydrolase via DNA Methylation

To elucidate molecular mechanisms responsible for the sexually dimorphic phenotype of soluble epoxide hydrolase (sEH) expression, we tested the hypothesis that female-specific down-regulation of sEH expression is driven by estrogen-dependent methylation of the Ephx2 gene. Mesenteric arteries isolated from male, female, ovariectomized female (OV), and OV with estrogen replacement (OVE) mice, as well as the human cell line (HEK293T) were used. Methylation-specific PCR and bisulfite genomic sequencing analysis indicate significant increases in DNA/CG methylation in vessels of female and OVE compared with those of male and OV mice. The same increase in CG methylation was also observed in male vessels incubated with a physiological concentration of 17beta-estradiol (17beta-E2) for 48 hours. All vessels that displayed increases in CG methylation were concomitantly associated with decreases in their Ephx2 mRNA and protein, suggesting a methylation-induced gene silencing. Transient transfection assays indicate that the activity of Ephx2 promoter-coding luciferase was significantly attenuated in HEK293T cells treated with 17beta-E2, which was prevented by additional treatment with an estrogen receptor antagonist (ICI). ChIP analysis indicates significantly reduced binding activities of transcription factors (including SP1, AP-1, and NF-kappaB with their binding elements located in the Ephx2 promoter) in vessels of female mice and human cells treated with 17beta-E2, responses that were prevented by ICI and Decitabine (DNA methyltransferase inhibitor), respectively. In conclusion, estrogen/estrogen receptor-dependent methylation of the promoter of Ephx2 gene silences sEH expression, which is involved in specific transcription factor-directed regulatory pathways

Isospin Effect on the Process of Multifragmentation and Dissipation at Intermediate Energy Heavy Ion Collisions

In the simulation of intermediate energy heavy ion collisions by using the isospin dependent quantum molecular dynamics, the isospin effect on the process of multifragmentation and dissipation has been studied. It is found that the multiplicity of intermediate mass fragments $N_{imf}$ for the neutron-poor colliding system is always larger than that for the neutron-rich system, while the quadrupole of single particle momentum distribution $Q_{zz}$ for the neutron-poor colliding system is smaller than that of the neutron-rich system for all projectile-target combinations studied at the beam energies from about 50MeV/nucleon to 150MeV/nucleon. Since $Q_{zz}$ depends strongly on isospin dependence of in-medium nucleon-nucleon cross section and weakly on symmetry potential at the above beam energies, it may serve as a good probe to extract the information on the in-medium nucleon-nucleon cross section. The correlation between the multiplicity $N_{imf}$ of intermediate mass fragments and the total numer of charged particles $N_c$ has the behavior similar to $Q_{zz}$, which can be used as a complementary probe to the in-medium nucleon-nucleon cross section.Comment: 18 pages, 9 figure

Enhanced surface acceleration of fast electrons by using sub-wavelength grating targets

Surface acceleration of fast electrons in intense laser-plasma interaction is improved by using sub-wavelength grating targets. The fast electron beam emitted along the target surface was enhanced by more than three times relative to that by using planar target. The total number of the fast electrons ejected from the front side of target was also increased by about one time. The method to enhance the surface acceleration of fast electron is effective for various targets with sub-wavelength structured surface, and can be applied widely in the cone-guided fast ignition, energetic ion acceleration, plasma device, and other high energy density physics experiments.Comment: 14 pages, 4figure

Hyperbolic Metamaterial Nanoparticles for Efficient Hyperthermia in the II and III Near-Infrared Windows

The use of gold nanoparticles for hyperthermia therapy in near infrared (NIR) spectral regions has catalysed substantial research efforts due to the potential impact in clinical therapy applications. However, the photoscattering effect scaling with the square of the nanoparticle volume leads to a low absorption efficiency, which has hindered the utility of gold nanoparticles in NIR II regions above 1000 nm. Here, we conquer this limit by introducing hyperbolic metamaterial nanoparticles that are made of multi-layered gold/dielectric nanodisks and exhibit >70% absorption efficiency in the NIR II and III regions. Their high light-to-heat conversion is demonstrated by a much larger temperature increase than that of gold nanodisks with the same amount of gold. Efficient in vitro hyperthermia of living cells with negligible cytotoxicity shows the potential of our approach for next-generation bio-medical applications