8 research outputs found
Anomalous stopping of laser-accelerated intense proton beam in dense ionized matter
Ultrahigh-intensity lasers (10-10W/cm) have opened up new
perspectives in many fields of research and application [1-5]. By irradiating a
thin foil, an ultrahigh accelerating field (10 V/m) can be formed and
multi-MeV ions with unprecedentedly high intensity (10A/cm) in short
time scale (ps) are produced [6-14]. Such beams provide new options in
radiography [15], high-yield neutron sources [16], high-energy-density-matter
generation [17], and ion fast ignition [18,19]. An accurate understanding of
the nonlinear behavior of beam transport in matter is crucial for all these
applications. We report here the first experimental evidence of anomalous
stopping of a laser-generated high-current proton beam in well-characterized
dense ionized matter. The observed stopping power is one order of magnitude
higher than single-particle slowing-down theory predictions. We attribute this
phenomenon to collective effects where the intense beam drives an decelerating
electric field approaching 1GV/m in the dense ionized matter. This finding will
have considerable impact on the future path to inertial fusion energy.Comment: 8 pages, 4 figure
Target density effects on charge tansfer of laser-accelerated carbon ions in dense plasma
We report on charge state measurements of laser-accelerated carbon ions in
the energy range of several MeV penetrating a dense partially ionized plasma.
The plasma was generated by irradiation of a foam target with laser-induced
hohlraum radiation in the soft X-ray regime. We used the tri-cellulose acetate
(CHO) foam of 2 mg/cm density, and -mm interaction
length as target material. This kind of plasma is advantageous for
high-precision measurements, due to good uniformity and long lifetime compared
to the ion pulse length and the interaction duration. The plasma parameters
were diagnosed to be T=17 eV and n=4 10 cm.
The average charge states passing through the plasma were observed to be higher
than those predicted by the commonly-used semiempirical formula. Through
solving the rate equations, we attribute the enhancement to the target density
effects which will increase the ionization rates on one hand and reduce the
electron capture rates on the other hand. In previsous measurement with
partially ionized plasma from gas discharge and z-pinch to laser direct
irradiation, no target density effects were ever demonstrated. For the first
time, we were able to experimentally prove that target density effects start to
play a significant role in plasma near the critical density of Nd-Glass laser
radiation. The finding is important for heavy ion beam driven high energy
density physics and fast ignitions.Comment: 7 pages, 4 figures, 35 conference
Improving the Performances of Random Copolymer Based Organic Solar Cells by Adjusting the Film Features of Active Layers Using Mixed Solvents
A novel random copolymer based on donor–acceptor type polymers containing benzodithiophene and dithienosilole as donors and benzothiazole and diketopyrrolopyrrole as acceptors was designed and synthesized by Stille copolymerization, and their optical, electrochemical, charge transport, and photovoltaic properties were investigated. This copolymer with high molecular weight exhibited broad and strong absorption covering the spectra range from 500 to 800 nm with absorption maxima at around 750 nm, which would be very conducive to obtaining large short-circuits current densities. Unlike the general approach using single solvent to prepare the active layer film, mixed solvents were introduced to change the film feature and improve the morphology of the active layer, which lead to a significant improvement of the power conversion efficiency. These results indicate that constructing random copolymer with multiple donor and acceptor monomers and choosing proper mixed solvents to change the characteristics of the film is a very promising way for manufacturing organic solar cells with large current density and high power conversion efficiency
LncRNAs‐circRNAs as Rising Epigenetic Binary Superstars in Regulating Lipid Metabolic Reprogramming of Cancers
Abstract As one of novel hallmarks of cancer, lipid metabolic reprogramming has recently been becoming fascinating and widely studied. Lipid metabolic reprogramming in cancer is shown to support carcinogenesis, progression, distal metastasis, and chemotherapy resistance by generating ATP, biosynthesizing macromolecules, and maintaining appropriate redox status. Notably, increasing evidence confirms that lipid metabolic reprogramming is under the control of dysregulated non‐coding RNAs in cancer, especially lncRNAs and circRNAs. This review highlights the present research findings on the aberrantly expressed lncRNAs and circRNAs involved in the lipid metabolic reprogramming of cancer. Emphasis is placed on their regulatory targets in lipid metabolic reprogramming and associated mechanisms, including the clinical relevance in cancer through lipid metabolism modulation. Such insights will be pivotal in identifying new theranostic targets and treatment strategies for cancer patients afflicted with lipid metabolic reprogramming