CAS Shanghai Institute of Applied Physics

Shanghai, China

CAS Shanghai Institute of Applied Physics

Shanghai, China

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Ma G.-L.,CAS Shanghai Institute of Applied Physics | Bzdak A.,Brookhaven National Laboratory
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2014

We show that the incoherent elastic scattering of partons, as present in a multi-phase transport model (AMPT), with a modest parton-parton cross-section of σ. =. 1.5-3 mb, naturally explains the long-range two-particle azimuthal correlation as observed in proton-proton and proton-nucleus collisions at the Large Hadron Collider. © 2014 The Authors.


Ma G.-L.,CAS Shanghai Institute of Applied Physics
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2014

Within a multi-phase transport (AMPT) model with the string melting mechanism and imported initial electric quadrupole moment, the difference between the elliptic flow of positive and negative pions is calculated. The slope parameter r of the linear dependence of δv2=v2(π-)-v2(π+) on A ch = (N + - N -)/(N + + N -) is yielded owing to the parton cascade, which converts the initial electric quadrupole distribution into the final charge-dependent elliptic flow. The slope parameter r is found to be increased by the hadronization given by the coalescence, and decreased by the resonance decays. The slope parameter r is very sensitive to both the initial electric quadrupole percentage and centrality bin and consequently a helpful constraint on the quadrupole moment of the chiral magnetic wave is obtained for Au + Au collisions at the top RHIC energy. © 2014 Elsevier B.V.


Zhu Y.,CAS Shanghai Institute of Applied Physics
Nuclear Physics A | Year: 2013

We report preliminary results on HΛ3 production in Au + Au collisions at RHIC at √sNN=7.7, 11.5, 19.6, 27, 39, and 200 GeV. The beam energy dependence of strangeness population factor HΛ3/3HeΛ/p is shown and the result indicates that HΛ3/3HeΛ/p has an increasing trend with 1.7. σ significance. The hypertriton lifetime combining the above Au + Au collision data set is measured to be 123±2226(stat)±10(sys) ps. © 2013 Elsevier B.V.


Ma G.-L.,CAS Shanghai Institute of Applied Physics
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2013

Within a multi-phase transport (AMPT) model with string melting scenario, the transverse momentum imbalance between prompt photon and jet is studied in Pb+Pb collisions at sNN=2.76TeV. Jet loses more energy in more central collisions due to strong partonic interactions between jet parton shower and partonic matter, which is more significant than due to hadronic interactions only. The hadronization and final-state hadronic interactions have little influences on the imbalance. The imbalance ratio xjγ is sensitive to both production position and passing direction of γ-jet, which provides an opportunity to do detail γ-jet tomography on the formed partonic matter by selecting different xjγ ranges. It is also proposed that γ-hadron azimuthal correlation associated with photon+jet is a probe to see the medium responses to different γ-jet production configurations. © 2013 Elsevier B.V.


Ma G.-L.,CAS Shanghai Institute of Applied Physics
Physical Review C - Nuclear Physics | Year: 2013

Within a multiphase transport (AMPT) model, dijet asymmetry is studied in Pb+Pb collisions at √sNN=2.76 TeV. It is found that a large dijet asymmetry (AJ) is produced by strong interactions between jets and partonic matter. It is demonstrated that hadronization and final-state hadronic rescatterings have little effect on AJ. The final A J is found to be driven by both initial AJ and partonic jet energy loss, which is consistent with an increasing jet energy loss in a hot and strongly interacting partonic medium in more central Pb+Pb collisions. © 2013 American Physical Society.


Deng H.,CAS Shanghai Institute of Applied Physics | Feng C.,CAS Shanghai Institute of Applied Physics
Physical Review Letters | Year: 2013

To improve temporal coherence in electron beam based light sources, various techniques employ frequency up conversion of external seed sources via electron beam density modulation; however, the energy spread of the beam may hinder the harmonic generation efficiency. In this Letter, a method is described for cooling the electron beam energy spread by off-resonance seed laser modulation, through the use of a transversely dispersed electron beam and a modulator undulator with an appropriate transverse field gradient. With this novel mechanism, it is shown that the frequency up-conversion efficiency can be significantly enhanced. We present theoretical analysis and numerical simulations for seeded soft x-ray free-electron laser and storage ring based coherent harmonic generation in the extreme ultraviolet spectral region. © 2013 American Physical Society.


Ma G.-L.,CAS Shanghai Institute of Applied Physics
Physical Review C - Nuclear Physics | Year: 2014

Within a multiphase transport model, medium modifications of differential jet shapes are investigated in Pb+Pb collisions at sNN = 2.76 TeV. The differential jet shapes are significantly modified by the strong interactions between jets and a partonic medium in Pb+Pb collisions relative to that in p+p collisions. The modifications are slightly weakened by the hadronization of coalescence, but strengthened by resonance decays in hadronic rescatterings. Subleading jets display larger medium modifications than leading jets, especially in central Pb+Pb collisions with large dijet asymmetries. These behaviors of medium modifications of differential jet shapes reflect a dynamical evolution of redistribution of jet energy inside a quenched jet cone in high-energy heavy-ion collisions. © 2014 American Physical Society.


Wen Y.,CAS Shanghai Institute of Applied Physics
Analytical chemistry | Year: 2011

The sensitivity of aptamer-based electrochemical sensors is often limited by restricted target accessibility and surface-induced perturbation of the aptamer structure, which arise from imperfect packing of probes on the heterogeneous and locally crowded surface. In this study, we have developed an ultrasensitive and highly selective electrochemical aptamer-based cocaine sensor (EACS), based on a DNA nanotechnology-based sensing platform. We have found that the electrode surface decorated with an aptamer probe-pendant tetrahedral DNA nanostructure greatly facilitates cocaine-induced fusion of the split anticocaine aptamer. This novel design leads to a sensitive cocaine sensor with a remarkably low detection limit of 33 nM. It is also important that the tetrahedra-decorated surface is protein-resistant, which not only suits the enzyme-based signal amplification scheme employed in this work, but ensures high selectivity of this sensor when deployed in sera or other adulterated samples.


Li D.,CAS Shanghai Institute of Applied Physics | Song S.,CAS Shanghai Institute of Applied Physics | Fan C.,CAS Shanghai Institute of Applied Physics
Accounts of Chemical Research | Year: 2010

Interest in the development of sensitive, selective, rapid, and cost-effective biosensors for biomedical analysis, environmental monitoring, and the detection of bioterrorism agents is rapidly increasing. A classic biosensor directly transduces ligand-target binding events into a measurable physical readout. More recently, researchers have proposed novel biosensing strategies that couple ligand-induced structural switching of biomolecules with advanced optical and electronic transducers. This approach has proven to be a highly general platform for the development of new biosensors. In this Account, we describe a series of electrochemical and optical nucleic acid sensors that use target-responsive DNA structures. By employing surface-confined DNA structures with appropriate redox labels, we can monitor target-induced structural switching of DNA or aptamer-specific small molecule probes by measuring electrochemical currents that are directly associated with the distance between the redox label and the electrode surface. We have also demonstrated significant improvements in sensing performance through optimization of the DNA self-assembly process at electrode surfaces or the introduction of nanomaterial-based signal amplification. Alternatively, gold nanoparticles interact differently with folded and unfolded DNA structures, which provides a visual method for detecting target-induced structural switching based on the plasmonic change of gold nanoparticles. This novel method using gold nanoparticles has proven particularly suitable for the detection of a range of small-molecule targets (e.g., cocaine) and environmentally toxic metal ions (e.g., Hg2+). Rational sequence design of DNA aptamers improves the sensitivity and increases the reaction kinetics. Recently, we have also designed microfluidic devices that allow rapid and portable mercury detection with the naked eye. This Account focuses on the use of bulk and nanoscale gold and DNA/aptamer molecules. We expect that researchers will further expand the analyte spectrum and improve the sensitivity and selectivity of nucleic acid sensors using functional biomolecules, such as DNAzymes, peptide aptamers and engineered proteins, and nanomaterials of different sizes, dimensions and compositions, such as carbon nanotubes, graphene, silicon nanowires, and metal nanoparticles or nanorods. © 2010 American Chemical Society.


Patent
CAS Shanghai Institute of Applied Physics | Date: 2014-12-02

The present invention provides an integrated type microfluidic electrochemical biosensor system for rapid biochemical analysis and the usage of the system. The system comprising: a continuous feeding unit for sequentially conveying lead eluent, sample solution, sample eluent, signal probe solution, signal probe eluent and electrochemical detection buffer solution; a microfluidic chip consists of one or more micro-channel network, the microfluidic chip covers the electrode array to form a channel system, capture probes which have interaction with the said sample solution fixed on the surface of the electrode array, said channel system is connected with the continuous feed unit; and a power system for providing power to said continuous feeding unit. The invention innovatively combine three technologies of planar electrode arrays, microfluidic chip technology and continuous feeding unit together, and the integrated type microfluidic electrochemical biosensing system which is small in size and low in cost and has a wide application prospect is provided.

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