作者机构：
[Hwa, RC] Univ Oregon, Inst Theoret Sci, Eugene, OR 97403 USA.;Univ Oregon, Dept Phys, Eugene, OR 97403 USA.;Huazhong Normal Univ, Inst Particle Phys, Wuhan 430079, Peoples R China.
通讯机构：
[Hwa, RC] U;Univ Oregon, Inst Theoret Sci, Eugene, OR 97403 USA.
摘要：
We study the production of hadrons in Au+Au collisions in the region 0.6<xF<1.2, which we refer to as the transfragmentation region (TFR), since it corresponds roughly to η′>0, where η′=η−ybeam, depending on the transverse momentum pT. We show how hadrons can be produced in that region when the hadronization process is parton recombination. The inclusive x distributions for proton and pion production are calculated with momentum degradation taken into account. The results show that the proton yield is significantly higher than that of the pions in the TFR. Without particle identification, the existing data cannot be used for comparison with our result on the p/π ratio. Without pT determination, it is not feasible to relate the x distribution to the experimental η′ distribution. Nevertheless, on theoretical grounds we have shown why the production of hadrons in the TFR is not forbidden by momentum conservation.
期刊：
JOURNAL OF PHYSICS G-NUCLEAR AND PARTICLE PHYSICS,2006年32(3):243-250 ISSN：0954-3899
通讯作者：
Sa, BH
作者机构：
China Inst Atom Energy, Beijing 102413, Peoples R China.;Huazhong Normal Univ, Inst Particle Phys, Wuhan 430079, Peoples R China.;Acad Sinica, Inst Theoret Phys, Beijing 100080, Peoples R China.;[Sa, BH] China Inst Atom Energy, POB 275 18, Beijing 102413, Peoples R China.
通讯机构：
[Sa, BH] C;China Inst Atom Energy, POB 275 18, Beijing 102413, Peoples R China.
摘要：
The BRAHMS and PHOBOS collaborations recently revisited the limiting fragmentation shown in the charged particle pseudorapidity density distribution in Au + Au collisions at RHIC energies. The PHOBOS collaboration especially emphasized that the observations of the charged particle universal (pseudo)rapidity scaling (limiting fragmentation) in and Au + Au collisions at relativistic energies may play an important role in the study of reaction dynamics. We use a parton and hadron cascade model, PACIAE, to investigate the charged particle universal (pseudo)rapidity scaling in the above collisions. It is pointed out that, because the universal scaling was observed in the tail region of the (pseudo)rapidity distributions, the discrepancies among distributions may not be properly visible. Therefore, this universal scaling may not have much to do with reaction dynamics, especially quark–gluon plasma. In addition, the charged particle universal scaling observed in the hadronic final state seems to arise from the partonic initial state.
作者机构：
[Ha, Zhijie; Li, Yuanyuan; Liu, Jinping; Li, YY] Cent China Normal Univ, Dept Phys, Ctr Nano Sci & Technol, Wuhan 430079, Peoples R China.
通讯机构：
[Li, Yuanyuan] C;Cent China Normal Univ, Dept Phys, Ctr Nano Sci & Technol, Wuhan 430079, Peoples R China.
关键词：
nanostructures;chemical synthesis;scanning and transmission electron microscopy
摘要：
An experimental procedure is presented for synthesis of AlOOH nanofibers by a hydrothermal process in aqueous solution of cetyltrimethyl ammonium bromide (CTAB) surfactant at 200 degrees C. The structure, morphology, purity and size of the products are investigated by powder X-ray diffraction (XRD), transmission electron microscopy (TEM) and standard selected area electron diffraction (SAED). A possible formation mechanism of the AlOOH nanostructures is proposed based on the reaction dynamics process and the surfactant-assisted growth. (c) 2006 Elsevier B.V. All rights reserved.
期刊：
Journal of Solid State Chemistry,2006年179(3):843-848 ISSN：0022-4596
通讯作者：
Huang, XT
作者机构：
[Huang, XT; Liu, JP] Cent China Normal Univ, Dept Phys, Ctr Nanosci & Technol, Wuhan 430079, Peoples R China.;[Huang, XT] Cent China Normal Univ, Dept Phys, Ctr Nanosci & Technol, 152-7 Luo Yu Rd, Wuhan 430079, Peoples R China.
通讯机构：
[Huang, XT] C;Cent China Normal Univ, Dept Phys, Ctr Nanosci & Technol, 152-7 Luo Yu Rd, Wuhan 430079, Peoples R China.
关键词：
crystal morphology;photoluminescence;growth from solutions;OPTICAL-PROPERTIES;OXIDE NANOSTRUCTURES;HYDROTHERMAL PROCESS;DEPOSITION METHOD;NANOWIRES;GROWTH;FABRICATION;MICROTUBES;NANORODS;ROUTE
摘要：
We have successfully synthesized single-crystal ZnO nanotubes and tubular whiskers by employing Zn(NO3)(2) center dot 6H(2)O, NH3 center dot H2O as the starting materials in the presence of polyethylene glycol (PEG, M-w = 2000) at ambient pressure and low temperature (70 degrees C). Characterizations are carried out by X-ray powder diffraction (XRD), X-ray energy dispersive spectroscopy (EDS), scanning electron microscopy (SEM), transmission electron microscopy (TEM, HRTEM) and photoluminescence (PL) measurement, The results show that the as-prepared ZnO are tubular textures, which have average cross-sectional dimensions of 200-300 nm, lengths of 2-3.5 mu m, and wall thickness of 80 nm. These tubular products demonstrate a sharp ultraviolet excitonic emission peak centered at 385 nm at room temperature. A possible growth mechanism and the influence of the reaction temperature on the formation of crystalline ZnO are presented. (C) 2005 Elsevier Inc. All rights reserved.
通讯机构：
[Liu, Shouyin] H;Huazhong Normal Univ, Dept Elect & Informat Engn, Wuhan 430079, Peoples R China.
会议名称：
10th International Conference on Communication Technology (ICCT 2006)
会议时间：
NOV 27-30, 2006
会议地点：
Guilin, PEOPLES R CHINA
会议主办单位：
[Liu, Shouyin;Zhan, Jinjing;Xie, Wenwu;Li, Fan] Huazhong Normal Univ, Dept Elect & Informat Engn, Wuhan 430079, Peoples R China.
摘要：
This paper proposes a new channel estimation method based on frequency-domain superimposed pilot time-domain correlation (FSPTC) for orthogonal frequency division multiplexing (OFDM) systems. In this scheme, pilots are directly added on information symbols in frequency-domain at the transmitter without consuming extra bandwidth. At the receiver, we acquire the coarse estimation of channel and information symbols through the correlation between the known pilots and the received signals. More accurate estimation is obtained by iterative operations, which eliminate the effect of unknown information symbols on pilot correlation. The effect of parameters - total number of sub-carriers, the pilot period and the pilot power ratio - on estimation performance is discussed in theory and simulation. The simulation results show that the system performance of our proposed scheme is approximate to the performance under the situation of ideal channel state information (CSI).
期刊：
INTERNATIONAL JOURNAL OF THEORETICAL PHYSICS,2006年45(12):2274-2281 ISSN：0020-7748
通讯作者：
Jiang, Qing-Quan
作者机构：
[Jiang, Qing-Quan] Cent China Normal Univ, Dept Phys, Wuhan 430079, Hubei, Peoples R China.;Cent China Normal Univ, Coll Phys Sci & Technol, Wuhan 430079, Hubei, Peoples R China.;China W Normal Univ, Inst Theoret Phys, Nanchong 637002, Sichuan, Peoples R China.
通讯机构：
[Jiang, Qing-Quan] C;Cent China Normal Univ, Dept Phys, Wuhan 430079, Hubei, Peoples R China.
摘要：
The charge and spin Hall conductance of the two-dimensional hole gas within the Luttinger model with and without inversion symmetry breaking terms in a perpendicular magnetic field are studied, and two key phenomena are predicted. The sign of the spin Hall conductance is modulated periodically by the external magnetic field, which means a possible application in the future. Furthermore, a resonant spin Hall conductance in the two-dimensional hole gas with a certain hole density at a typical magnetic field is indicated, which implies a likely way to firmly establish the intrinsic spin Hall effect. The charge Hall conductance is unaffected by the spin-orbit coupling.
作者机构：
[Werner, Klaus; Liu, Fu-Ming] Cent China Normal Univ, Inst Particle Phys, Wuhan 430070, Peoples R China.
通讯机构：
[Liu, Fu-Ming] C;Cent China Normal Univ, Inst Particle Phys, Wuhan 430070, Peoples R China.
摘要：
The existence of pentaquarks, namely, baryonic states made up of four quarks and one antiquark, became questionable, because the candidates, i.e. the Θ+ peak, are seen in certain reactions, i.e. p+p collisions, but not in others, i.e. e+e− annihilations. In this paper, we estimate the production of Θ+(1540) and Ξ--(1860) in e+e− annihilations at different energies using the Fermi statistical model as originally proposed in its microcanonical form. The results are compared with that from proton-proton (pp) collisions at SPS (CERN’s superconducting proton synchrotron) and RHIC (relativistic heavy ion collisions at Brookhaven) energies. We find that, if pentaquark states exist, the production is highly possible in e+e− annihilations. For example, at LEP energy s=91.2 GeV, both Θ+(1540) and Ξ--(1860) yield more than in pp collisions at SPS and RHIC energy.
