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Search Results: 1 - 10 of 19477 matches for " Haiyan Gao "
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Status on nucleon electromagnetic form factors
Haiyan Gao
Physics , 2003, DOI: 10.1142/S021830130300117X
Abstract: Nucleon electromagnetic form factors are fundamental quantities related to the charge and magnetization distributions inside the nucleon. Understanding the nucleon electromagnetic structure in terms of the underlying quark and gluon degrees of freedom of quantum chromodynamics is a challenging and urgent task. The nucleon electromagnetic form factors have been studied in the past extensively from unpolarized electron scattering experiments. With the development in polarized beam, recoil polarimetry, and polarized target technologies, polarization experiments have provided more precise data on these quantities. At the same time, significant theoretical progress in areas ranging from effective field theories to lattice QCD calculations, has been made in describing these data. In this article, we review recent experimental and theoretical progress on this subject. we also provide future outlook on this topic.
Neutron Electromagnetic Form Factors
Haiyan Gao
Physics , 2004, DOI: 10.1142/S0217751X05023049
Abstract: The nucleon electromagnetic form factors have been studied in the past extensively from unpolarized electron scattering experiments. With the development in polarized beam, recoil polarimetry, and polarized target technologies, polarization experiments have provided more precise data on these quantities. In this talk, I review recent experimental progress on this subject.
High Resolution Search for Exotic Pentaquark $Θ^{++}$, and $Θ^+$ at Jefferson Lab
Haiyan Gao,Wang Xu
Physics , 2004,
Abstract: Recent evidence for the existence of pentaquark $\Theta^+$ particle from several experiments at several different laboratories around the world has caused great excitement and raised many unanswered questions. We discuss a new proposal on a high resolution experiment searching for pentaquark states in Hall C at Jefferson Lab using an untagged bremsstrahlung photon beam employing both the hydrogen and the deuterium targets by studying the following processes: $\gamma p \to \Theta^{++} K^-$, and $\gamma n \to \Theta^+ K^-$. This new experiment will significantly improve our current knowledge of the mass, the width of the $\Theta^+$ particle if it is confirmed and provide unambiguous evidence for the existence or non-existence of the $\Theta^{++}$ particle from the \gamma p \to \Theta^{++} K^-$ process.
Pion photoproduction on the nucleon
Haiyan Gao,Lingyan Zhu
Physics , 2004, DOI: 10.1063/1.1871659
Abstract: The $\gamma n \to \pi^- p$ and $\gamma p \to \pi^+ n$ reactions are essential probes of the transition from meson-nucleon degrees of freedom to quark-gluon degrees of freedom in exclusive processes. The cross sections of these processes are also advantageous, for the investigation of oscillatory behavior around the quark counting prediction, since they decrease relatively slower with energy compared with other photon-induced processes. In this talk, we discuss recent results on the $\gamma p \to \pi^+ n$ and $\gamma n \to \pi^{-}p$ processes from Jefferson Lab experiment E94-104. We also discuss a new experiment in which singles $\gamma p \to \pi^+ n$ measurement from hydrogen, and coincidence $\gamma n \to \pi^{-} p$ measurements at the quasifree kinematics from deuterium for center-of-mass energies between 2.3 GeV to 3.4 GeV in fine steps at a center-of-mass angle of $90^\circ$ are planned. The proposed measurement will allow a detailed investigation of the oscillatory scaling behavior in photopion production processes.
Direct Writing of Flexible Electronics through Room Temperature Liquid Metal Ink
Yunxia Gao, Haiyan Li, Jing Liu
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0045485
Abstract: Background Conventional approaches of making a flexible circuit are generally complex, environment unfriendly, time and energy consuming, and thus expensive. Here, we describe for the first time the method of using high-performance GaIn10-based electrical ink, a significantly neglected room temperature liquid metal, as both electrical conductors and interconnects, for directly writing flexible electronics via a rather easy going and cost effective way. Methods The new generation electric ink was made and its wettability with various materials was modified to be easily written on a group of either soft or rigid substrates such as epoxy resin board, glass, plastic, silica gel, paper, cotton, textiles, cloth and fiber etc. Conceptual experiments were performed to demonstrate and evaluate the capability of directly writing the electrical circuits via the invented metal ink. Mechanisms involved were interpreted through a series of fundamental measurements. Results The electrical resistivity of the fluid like GaIn10-based material was measured as 34.5 μΩ·cm at 297 K by four point probe method and increased with addition of the oxygen quantity, which indicates it as an excellent metal ink. The conductive line can be written with features that are approximately 10 μm thick. Several functional devices such as a light emitting diode (LED) array showing designed lighting patterns and electrical fan were made to work by directly writing the liquid metal on the specific flexible substrates. And satisfactory performances were obtained. Conclusions The present method opens the way to directly and quickly writing flexible electronics which can be as simple as signing a name or drawing a picture on the paper. The unique merit of the GaIn10-based liquid metal ink lies in its low melting temperature, well controlled wettability, high electrical conductivity and good biocompability. The new electronics writing strategy and basic principle has generalized purpose and can be extended to more industrial areas, even daily life.
An Efficient Method of Web Sequential Pattern Mining Based on Session Filter and Transaction Identification
Jingjun Zhu,Haiyan Wu,Guozhu Gao
Journal of Networks , 2010, DOI: 10.4304/jnw.5.9.1017-1024
Abstract: Web sequential pattern mining is an important way to analyze the access behavior of web users. In this paper, we present an efficient method of web sequential pattern mining based on session filter and transaction identification. Different from traditional mining methods, we categorize the user sessions into human user sessions, crawler sessions and resource-download user sessions. Then we filter out the non-human user sessions, leaving the human user sessions for sequential pattern mining. With the purpose of mining users’ meaningful sequential patterns, we identify users’ transactions from the user sessions, and do the sequential pattern mining based on transaction level. We present a method of transaction identification based on users’ access path tree. It can find out all the transactions effectively. We also make some improvements on PrefixSpan algorithm, which can reduce the memory space it takes and avoid generating duplicate projections. The experimental results of our mining method are very satisfactory.
Directly Writing Resistor, Inductor and Capacitor to Composite Functional Circuits: A Super-Simple Way for Alternative Electronics
Yunxia Gao, Haiyan Li, Jing Liu
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0069761
Abstract: Background The current strategies for making electronic devices are generally time, water, material and energy consuming. Here, the direct writing of composite functional circuits through comprehensive use of GaIn10-based liquid metal inks and matching material is proposed and investigated, which is a rather easy going and cost effective electronics fabrication way compared with the conventional approaches. Methods Owing to its excellent adhesion and electrical properties, the liquid metal ink was demonstrated as a generalist in directly making various basic electronic components such as planar resistor, inductor and capacitor or their combination and thus composing circuits with expected electrical functions. For a precise control of the geometric sizes of the writing, a mask with a designed pattern was employed and demonstrated. Mechanisms for justifying the chemical components of the inks and the magnitudes of the target electronic elements so as to compose various practical circuits were disclosed. Results Fundamental tests on the electrical components including capacitor and inductor directly written on paper with working time up to 48 h and elevated temperature demonstrated their good stability and potential widespread adaptability especially when used in some high frequency circuits. As the first proof-of-concept experiment, a typical functional oscillating circuit including an integrated chip of 74HC04 with a supply voltage of 5 V, a capacitor of 10 nF and two resistors of 5 kΩ and 1 kΩ respectively was directly composed on paper through integrating specific electrical elements together, which presented an oscillation frequency of 8.8 kHz. Conclusions The present method significantly extends the roles of the metal ink in recent works serving as only a single electrical conductor or interconnecting wires. It opens the way for directly writing out complex functional circuits or devices on different substrates. Such circuit composition strategy has generalized purpose and can be extended to more areas, even daily pervasive electronics.
Exotic Hadrons Of Minimal Pentaquark ($qqqq\Bar{Q}$) States
Haiyan Gao,Bo-Qiang Ma
Physics , 2003, DOI: 10.1142/S021773239900239X
Abstract: It is shown that the exotic non-qqq hadrons of pentaquark $qqqq\bar{q}$ states can be clearly distinguished from the conventional qqq-baryon resonances or their hybrids if the flavor of $\bar{q}$ is different from any of the other four quarks. We suggest the physical process $p(e,e'K^-)Z(uuud\bar{s})$, which can be investigated at the Thomas Jefferson National Accelerator Facility (JLab), as an ideal process to search for the existence or non-existence of the exotic hadron of minimal pentaquark state $Z(uuud\bar{s})$. (The search for the existence of $Z(uudd\bar{s})$ is also discussed in the paper. We added this sentence after the original published form of this paper.)
Spectra of 2 × 2 Upper-Triangular Operator Matrices  [PDF]
Haiyan Zhang
Applied Mathematics (AM) , 2013, DOI: 10.4236/am.2013.411A1004
Abstract:

In [Perturbation of Spectrums of 2 × 2 Operator Matrices, Proceedings of the American Mathematical Society, Vol. 121, 1994], the authors asked whether there was an operator \"\" such that \"\" for a given pair (A,B) of operators, where the operator \"\" was defined by \"\". In this note, a partial answer for the question is given.

Reader-Friendly Navigator for Global Tax Treaty Cases—Book Review of “A Global Analysis of Tax Treaty Disputes”  [PDF]
Haiyan Xu
Beijing Law Review (BLR) , 2018, DOI: 10.4236/blr.2018.92009
Abstract: This paper is a book review for the informative and thoughtful book “A Global Analysis of Tax Treaty Disputes”, edited by Prof. Eduardo Baistrocchi. As one of the first readers of this book, I firmly believe that it is a most fascinating pioneering work on global and comparative analysis of tax treaty disputes from empirical approach.
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