2,013 research outputs found

    Effects of Aromatic Ammoniums on Methyl Ammonium Lead Iodide Hybrid Perovskite Materials

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    The introduction of bulky ammoniums into methyl ammonium lead iodide hybrid perovskites (MAPbI3) has emerged as a promising strategy to improve the properties of these materials. In the present work, we studied the effects of several aromatic ammoniums onto the structural, electronic, and optical properties of MAPbI3. Although powder XRD data suggest that the bulky cations are not involved in the bulk phase of the MAPbI3, a surprisingly large effect of the bulky cations onto the photoluminescence properties was observed

    Charm Quarks Are More Hydrodynamic Than Light Quarks in Final-State Elliptic Flow

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    We study the charm quark elliptic flow (v2v_{2}) in heavy ion as well as small system collisions by tracking the evolution history of quarks of different flavors within a multi-phase transport model. The charm quark v2v_{2} is studied as a function of the number of collisions the charm quark suffers with other quarks and then compared to the v2v_{2} of lighter quarks. We find that the common escape mechanism is at work for both the charm and light quark v2v_{2}. However, contrary to the naive expectation, the hydrodynamics-type flow is found to contribute more to the final state charm v2v_{2} than light quark v2v_{2}. This could be explained by the smaller average deflection angle the heavier charm quark undergoes in each collision, so that heavy quarks need more scatterings to accumulate a significant v2v_{2}, while lighter quarks can more easily change directions with scatterings with their v2v_{2} coming more from the escape mechanism. Our finding thus suggests that the charm v2v_{2} is a better probe for studying the hydrodynamic properties of the quark-gluon plasma.Comment: 10 pages, 4 figure

    Ant-behavior inspired intelligent nanonet for targeted drug delivery in cancer therapy

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    Targeted drug delivery system is believed as one of the most promising solutions for cancer treatment due to its low-dose requirement and less side effects. However, both passive targeting and active targeting rely on systemic blood circulation and diffusion, which is actually not the real β€œactive” drug delivery. In this paper, an ant-behavior inspired nanonetwork composing of intelligent nanomachines is proposed. A big intelligent nanomachine take small intelligent nanomachines and drugs to the vicinity of of the tumor area. The small intelligent nanomachines can coordinate with each other to find the most effective path to the tumor cell for drug transportation. The framework and mechanism of this cooperative network are proposed. The route finding algorithm is presented. The convergence performance is analytically analyzed where the influence of the factors such as molecule degradation rate, home-destination distance, number of small nanomachines to the convergence is presented. Finally the simulation results validate the effectiveness of the proposed mechanism and analytical analysi

    Large Eddy Simulation analysis on confined swirling flows in a gas turbine swirl burner

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    This paper describes a Large Eddy Simulation (LES) investigation into flow fields in a model gas turbine combustor equipped with a swirl burner. A probability density function was used to describe the interaction physics of chemical reaction and turbulent flow as liquid fuel was directly injected into the combustion chamber and rapidly mixed with the swirling air. Simulation results showed that heat release during combustion accelerated the axial velocity motion and made the recirculation zone more compact. As the combustion was taking place under lean burn conditions, NO emissions was less than 10 ppm. Finally, the effects of outlet contraction on swirling flows and combustion instability were investigated. Results suggest that contracted outlet can enhance the generation of a Central Vortex Core (CVC) flow structure. As peak RMS of velocity fluctuation profiles at center-line suggested the turbulent instability can be enhanced by CVC motion, the Power Spectrum Density (PSD) amplitude also explained that the oscillation at CVC position was greater than other places. Both evidences demonstrated that outlet contraction can increase the instability of the central field. Β [m1]Is’t right? Yes

    Re-examining the premise of isobaric collisions and a novel method to measure the chiral magnetic effect

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    In these proceedings we show that the premise of the isobaric and collisions to search for the chiral magnetic effect (CME) may not hold as originally anticipated due to large uncertainties in the isobaric nuclear structures. We demonstrate this using Woods-Saxon densities and the proton and neutron densities calculated by the density functional theory. Furthermore, a novel method is proposed to gauge background and possible CME contributions in the same system, intrinsically better than the isobaric collisions of two different systems. We illustrate the method with Monte Carlo Glauber and AMPT (A Multi-Phase Transport) simulations

    Design and Analysis of a Through-Body Signal Transmission System Based on Human Oxygen Saturation Detection

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    For a long time, people have carried out various studies on molecular communication (MC) and the Internet of Bio-Nanothings (IoBNT) in order to realize biomedical applications inside the human body. However, how to realize the communication between these applications and the outside body has become a new problem. In general, different components in the blood have different light absorption rates. Based on this, we propose a new through-body communication method. The nanomachine in the blood vessel transmits signals by releasing certain substances that can influence blood oxygen saturation. The change in blood oxygen saturation can be detected by an outside body device measuring the attenuation of the light through the blood. The framework of the entire communication system is proposed and mathematically modeled. Its error performance is discussed and evaluated. The mutual information (MI) of the designed communication system is also derived and calculated. This research will contribute to the realization of the connection of the IoBNT inside the human body to the outside device

    Heavy quark flow as better probes of QGP properties

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    In earlier studies we have proposed that most parton v2 comes from the anisotropic escape of partons, not from the hydrodynamic flow, even for semi-central Au+Au collisions at SNN = 200 GeV. Here we study the flavor dependence of this escape mechanism with a multi-phase transport model. In contrast to naive expectations, we find that the charm v2 is much more sensitive to the hydrodynamic flow than the lighter quark v2, and the fraction of v2 from the escape mechanism decreases strongly with the quark mass for large collision systems. We also find that the light quark collective flow is essential for the charm quark v2. Our finding thus suggests that heavy quark flows are better probes of the quark-gluon-plasma properties than light quark flows

    Origin of the Mass Splitting of Elliptic Anisotropy in a Multiphase Transport Model

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    The mass splitting of elliptic anisotropy (v2v_2) at low transverse momentum is considered as a hallmark of hydrodynamic collective flow. We investigate a multiphase transport (AMPT) model where the v2v_2 is mainly generated by an anisotropic escape mechanism, not of the hydrodynamic flow nature, and where mass splitting is also observed. We demonstrate that the v2v_2 mass splitting in AMPT is small right after hadronization (especially when resonance decays are included); the mass splitting mainly comes from hadronic rescatterings, even though their contribution to the overall charged hadron v2v_2 is small. These findings are qualitatively the same as those from hybrid models that combine hydrodynamics with a hadron cascade. We further show that there is no qualitative difference between heavy ion collisions and small system collisions. Our results indicate that the v2v_2 mass splitting is not a unique signature of hydrodynamic collective flow and thus cannot distinguish whether the elliptic flow is generated mainly from hydrodynamics or the anisotropic parton escape.Comment: 5 pages, 4 figure

    Origin of the mass splitting of azimuthal anisotropies in a multiphase transport model

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    Both hydrodynamics-based models and a multi-phase transport (AMPT) model can reproduce the mass splitting of azimuthal anisotropy (vnv_n) at low transverse momentum (pβŠ₯p_{\perp}) as observed in heavy ion collisions. In the AMPT model, however, vnv_n is mainly generated by the parton escape mechanism, not by the hydrodynamic flow. In this study we provide detailed results on the mass splitting of vnv_n in this transport model, including v2v_2 and v3v_3 of various hadron species in d+Au and Au+Au collisions at the Relativistic Heavy Ion Collider and p+Pb collisions at the Large Hadron Collider. We show that the mass splitting of hadron v2v_2 and v3v_3 in AMPT first arises from the kinematics in the quark coalescence hadronization process, and then, more dominantly, comes from hadronic rescatterings, even though the contribution from the latter to the overall charged hadron vnv_n is small. We further show that there is no qualitative difference between heavy ion collisions and small-system collisions or between elliptic (v2v_2) and triangular (v3v_3) anisotropies. Our studies thus demonstrate that the mass splitting of v2v_2 and v3v_3 at low-pβŠ₯p_{\perp} is not a unique signature of hydrodynamic collective flow but can be the interplay of several physics effects.Comment: 11 pages, 12 figures. Followup long paper to H. Li et al. Phys. Rev. C 93 (2016) 051901(R) (2016) [arXiv:1601.05390]; changes from v1 to v2: added phi-meson results in Fig.2 and Fig.11; v3: published versio
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