161 research outputs found
Achieving Stable Radiation Pressure Acceleration of Heavy Ions via Successive Electron Replenishment from Ionization of a High-Z Material Coating
A method to achieve stable radiation pressure acceleration (RPA) of heavy ions from laser-irradiated ultrathin foils is proposed, where a high-Z material coating in front is used. The coated high-Z material, acting as a moving electron repository, continuously replenishes the accelerating heavy ion foil with comoving electrons in the light-sail acceleration stage due to its successive ionization under laser fields with Gaussian temporal profile. As a result, the detrimental effects such as foil deformation and electron loss induced by the Rayleigh-Taylor-like and other instabilities in RPA are significantly offset and suppressed so that stable acceleration of heavy ions are maintained. Particle-in-cell simulations show that a monoenergetic Al13+ beam with peak energy 3.8 GeV and particle number 10(10) (charge > 20 nC) can be obtained at intensity 10(22) W/cm(2).NSAF [U1630246]; National Natural Science Foundation of China [11575298, 11575011]; National Key Program of S&T Research and Development [2016YFA0401100]; Science Challenging Project [TZ2016005]; Engineering and Physical Sciences Research Council (EPSRC) [EP/J002550/1, EP/K022415/1]; Thousand Young Talents Program of China; Special Program for Applied Research on Super Computation of the NSFC-Guangdong Joint FundSCI(E)ARTICLE2011
Global Incidence and mortality of oesophageal cancer and their correlation with socioeconomic indicators temporal patterns and trends in 41 countries
Oesophageal cancers (adenocarcinomas [AC] and squamous cell carcinomas [SCC]) are characterized by high incidence/mortality in many countries. We aimed to delineate its global incidence and mortality, and studied whether socioeconomic development and its incidence rate were correlated. The age-standardized rates (ASRs) of incidence and mortality of this medical condition in 2012 for 184 nations from the GLOBOCAN database; national databases capturing incidence rates, and the WHO mortality database were examined. Their correlations with two indicators of socioeconomic development were evaluated. Joinpoint regression analysis was used to generate trends. The ratio between the ASR of AC and SCC was strongly correlated with HDI (rβ=β0.535 [men]; rβ=β0.661 [women]) and GDP (rβ=β0.594 [men]; rβ=β0.550 [women], both pβ<β0.001). Countries that reported the largest reduction in incidence in male included Poland (Average Annual Percent Change [AAPC]β=ββ7.1, 95%C.I.β=ββ12,β1.9) and Singapore (AAPCβ=ββ5.8, 95%C.I.β=ββ9.5,β1.9), whereas for women the greatest decline was seen in Singapore (AAPCβ=ββ12.3, 95%C.I.β=ββ17.3,β6.9) and China (AAPCβ=ββ5.6, 95%C.I.β=ββ7.6,β3.4). The Philippines (AAPCβ=β4.3, 95%C.I.β=β2,6.6) and Bulgaria (AAPCβ=β2.8, 95%C.I.β=β0.5,5.1) had a significant mortality increase in men; whilst Columbia (AAPCβ=ββ6.1, 95%C.I.β=ββ7.5,β4.6) and Slovenia (AAPCβ=ββ4.6, 95%C.I.β=ββ7.9,β1.3) reported mortality decline in women. These findings inform individuals at increased risk for primary prevention
Two charged strangeonium-like structures observable in the process
Via the Initial Single Pion Emission (ISPE) mechanism, we study the
invariant mass spectrum distribution of . Our calculation indicates there exist a sharp peak
structure () close to the threshold and a broad
structure () near the threshold. In addition, we
also investigate the process due to
the ISPE mechanism, where a sharp peak around the threshold
appears in the invariant mass spectrum distribution. We
suggest to carry out the search for these charged strangeonium-like structures
in future experiment, especially Belle II, Super-B and BESIII.Comment: 7 pages, 5 figures. Accepted by Eur. Phys. J.
Study of J/Psi decays into eta Kstar Kstar-bar
We report the first observation of \mPJpsi \to \mPeta\mPKst\mAPKst decay in
a \mPJpsi sample of 58 million events collected with the BESII detector. The
branching fraction is determined to be . The selected signal event sample is further used to search for the
\mPY resonance through \mPJpsi \to \mPeta \mPY, \mPY\to\mPKst\mAPKst. No
evidence of a signal is seen. An upper limit of \mathrm{Br}(\mPJpsi \to \mPeta
\mPY)\cdot\mathrm{Br}(\mPY\to\mPKst\mAPKst) < 2.52\times 10^{-4} is set at the
90% confidence level.Comment: 11 pages, 4 figure
Generation of overdense and high-energy electron-positron-pair plasmas by irradiation of a thin foil with two ultraintense lasers
A scheme for enhanced quantum electrodynamics (QED) production of electron-positron-pair plasmas is proposed that uses two ultraintense lasers irradiating a thin solid foil from opposite sides. In the scheme, under a proper matching condition, in addition to the skin-depth emission of gamma-ray photons and Breit-Wheeler creation of pairs on each side of the foil, a large number of high-energy electrons and photons from one side can propagate through it and interact with the laser on the other side, leading to much enhanced gamma-ray emission and pair production. More importantly, the created pairs can be collected later and confined to the center by opposite laser radiation pressures when the foil becomes transparent, resulting in the formation of unprecedentedly overdense and high-energy pair plasmas. Two-dimensional QED particle-in-cell simulations show that electron-positron-pair plasmas with overcritical density 10(22) cm(-3) and a high energy of 100s of MeV are obtained with 10 PW lasers at intensities 10(23) W/cm(2), which are of key significance for laboratory astrophysics studies.National Natural Science Foundation of China [11575298, 91230205, 11575031, 11175026]; National Basic Research 973 Projects [2013CBA01500, 2013CB834100]; National High-Tech 863 Project; Thousand Young Talents Program of China; Engineering and Physical Sciences Research Council (EPSRC) [EP/1029206/1]SCI(E)[email protected]
Peak Observer Based Self-tuning of Type-2 Fuzzy PID Controllers
Part 11: Simulations and Fuzzy ModelingInternational audienceFuzzy PID (proportional-integral-derivative) controllers are commonly used as an alternative to the conventional PID controllers. In order to improve the control system performance of these controllers many self-tuning methods are already studied. It is mostly observed that the self-tuning mechanism should tune the scaling factors of the fuzzy controller to enhance the transient system performance. On the other hand, these studies only focus on the ordinary (Type-1) Fuzzy PID controllers. In this study, Type-2 Fuzzy PID controllers are studied and a peak observer based self-tuning method is proposed for these controllers. In order to show the benefit of the proposed approach, several Matlab simulations are performed where different type of fuzzy control structures are compared. The results obtained from the simulation studies clearly show the advantage of the proposed approach
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