885 resultados para MAC GIN


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We report new results on identified (anti) proton and charged pion spectra at large transverse momenta (3 < p(T) < 10 GeV/c) from Cu + Cu collisions at root s(NN) = 200 GeV using the STAR detector at the Relativistic Heavy Ion Collider (RHIC). This study explores the system size dependence of two novel features observed at RHIC with heavy ions: the hadron suppression at high-p(T) and the anomalous baryon to meson enhancement at intermediate transverse momenta. Both phenomena could be attributed to the creation of a new form of QCD matter. The results presented here bridge the system size gap between the available pp and Au + Au data, and allow for a detailed exploration of the onset of the novel features. Comparative analysis of all available 200 GeV data indicates that the system size is a major factor determining both the magnitude of the hadron spectra suppression at large transverse momenta and the relative baryon to meson enhancement.

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We present the results of an elliptic flow, v(2), analysis of Cu + Cu collisions recorded with the solenoidal tracker detector (STAR) at the BNL Relativistic Heavy Ion Collider at root s(NN) = 62.4 and 200 GeV. Elliptic flow as a function of transverse momentum, v(2)(p(T)), is reported for different collision centralities for charged hadrons h(+/-) and strangeness-ontaining hadrons K-S(0), Lambda, Xi, and phi in the midrapidity region vertical bar eta vertical bar < 1.0. Significant reduction in systematic uncertainty of the measurement due to nonflow effects has been achieved by correlating particles at midrapidity, vertical bar eta vertical bar < 1.0, with those at forward rapidity, 2.5 < vertical bar eta vertical bar < 4.0. We also present azimuthal correlations in p + p collisions at root s = 200 GeV to help in estimating nonflow effects. To study the system-size dependence of elliptic flow, we present a detailed comparison with previously published results from Au + Au collisions at root s(NN) = 200 GeV. We observe that v(2)(p(T)) of strange hadrons has similar scaling properties as were first observed in Au + Au collisions, that is, (i) at low transverse momenta, p(T) < 2 GeV/c, v(2) scales with transverse kinetic energy, m(T) - m, and (ii) at intermediate p(T), 2 < p(T) < 4 GeV/c, it scales with the number of constituent quarks, n(q.) We have found that ideal hydrodynamic calculations fail to reproduce the centrality dependence of v(2)(p(T)) for K-S(0) and Lambda. Eccentricity scaled v(2) values, v(2)/epsilon, are larger in more central collisions, suggesting stronger collective flow develops in more central collisions. The comparison with Au + Au collisions, which go further in density, shows that v(2)/epsilon depends on the system size, that is, the number of participants N-part. This indicates that the ideal hydrodynamic limit is not reached in Cu + Cu collisions, presumably because the assumption of thermalization is not attained.

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We present a measurement of pi(+)pi(-)pi(+)pi(-) photonuclear production in ultraperipheral Au-Au collisions at root s(NN) = 200 GeV from the STAR experiment. The pi(+)pi(-)pi(+)pi(-) final states are observed at low transverse momentum and are accompanied by mutual nuclear excitation of the beam particles. The strong enhancement of the production cross section at low transverse momentum is consistent with coherent photoproduction. The pi(+)pi(-)pi(+)pi(-) invariant mass spectrum of the coherent events exhibits a broad peak around 1540 +/- 40 MeV/c(2) with a width of 570 +/- 60 MeV/c(2), in agreement with the photoproduction data for the rho(0)(1700). We do not observe a corresponding peak in the pi(+)pi(-) final state and measure an upper limit for the ratio of the branching fractions of the rho(0)(1700) to pi(+)pi(-) and pi(+)pi(-)pi(+)pi(-) of 2.5% at 90% confidence level. The ratio of rho(0)(1700) and rho(0)(770) coherent production cross sections is measured to be 13.4 +/- 0.8(stat.) +/- 4.4(syst.)%.

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We present the first measurements of identified hadron production, azimuthal anisotropy, and pion interferometry from Au + Au collisions below the nominal injection energy at the BNL Relativistic Heavy-Ion Collider (RHIC) facility. The data were collected using the large acceptance solenoidal tracker at RHIC (STAR) detector at root s(NN) = 9.2 GeV from a test run of the collider in the year 2008. Midrapidity results on multiplicity density dN/dy in rapidity y, average transverse momentum < p(T)>, particle ratios, elliptic flow, and Hanbury-Brown-Twiss (HBT) radii are consistent with the corresponding results at similar root s(NN) from fixed-target experiments. Directed flow measurements are presented for both midrapidity and forward-rapidity regions. Furthermore the collision centrality dependence of identified particle dN/dy, < p(T)>, and particle ratios are discussed. These results also demonstrate that the capabilities of the STAR detector, although optimized for root s(NN) = 200 GeV, are suitable for the proposed QCD critical-point search and exploration of the QCD phase diagram at RHIC.

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Nuclear collisions recreate conditions in the universe microseconds after the Big Bang. Only a very small fraction of the emitted fragments are light nuclei, but these states are of fundamental interest. We report the observation of antihypertritons-comprising an antiproton, an antineutron, and an antilambda hyperon-produced by colliding gold nuclei at high energy. Our analysis yields 70 +/- 17 antihypertritons (3/Lambda(H) over bar) and 157 +/- 30 hypertritons (H-3(Lambda)). The measured yields of H-3(Lambda) (3/Lambda(H) over bar) and He-3 ((3)(He) over bar) are similar, suggesting an equilibrium in coordinate and momentum space populations of up, down, and strange quarks and antiquarks, unlike the pattern observed at lower collision energies. The production and properties of antinuclei, and of nuclei containing strange quarks, have implications spanning nuclear and particle physics, astrophysics, and cosmology.

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We present measurements of the charge balance function, from the charged particles, for diverse pseudorapidity and transverse momentum ranges in Au + Au collisions at root S-NN = 200 GeV using the STAR detector at RHIC. We observe that the balance function is boost-invariant within the pseudorapidity coverage vertical bar-1.3, 1.3 vertical bar. The balance function properly scaled by the width of the observed pseudorapidity window does not depend on the position or size of the pseudorapidity window. This scaling property also holds for particles in different transverse momentum ranges. In addition, we find that the width of the balance function decreases monotonically with increasing transverse momentum for all centrality classes. (c) 2010 Elsevier B.V. All rights reserved.

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We present the multiplicity and pseudorapidity distributions of photons produced in Au + Au and Cu + Cu collisions at root(NN)-N-s = 62.4 and 200 GeV. The photons are measured in the region -3.7 < eta < -2.3 using the photon Multiplicity detector in the STAR experiment at RHIC. The number of photons produced per average number of participating nucleon pairs increases with the beam energy and is independent of (lie collision centrality. For collisions with similar average numbers of participating nucleons the photon multiplicities are observed to be similar for An + Au and Cu + Cu collisions at a given beam energy. The ratios of the number of charged particles to photons in the measured pseudorapidity range are found to be 1.4 +/- 0.1 and 1.2 +/- 0.1 for root(NN)-N-s = 62.4 and 200 GeV, respectively. The energy dependence of this ratio could reflect varying contributions from baryons to charged particles, while mesons are the dominant contributors to photon production in the given kinematic region. The photon pseudorapidity distributions normalized by average number of participating nucleon pairs, when plotted as a function of eta-Y-beam, are found to follow a longitudinal scaling independent of centrality and colliding ion species at both beam energies. (C) 2009 Elsevier B.V. All rights reserved.

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The aim of this paper is to show that Dempster-Shafer evidence theory may be successfully applied to unsupervised classification in multisource remote sensing. Dempster-Shafer formulation allows for consideration of unions of classes, and to represent both imprecision and uncertainty, through the definition of belief and plausibility functions. These two functions, derived from mass function, are generally chosen in a supervised way. In this paper, the authors describe an unsupervised method, based on the comparison of monosource classification results, to select the classes necessary for Dempster-Shafer evidence combination and to define their mass functions. Data fusion is then performed, discarding invalid clusters (e.g. corresponding to conflicting information) thank to an iterative process. Unsupervised multisource classification algorithm is applied to MAC-Europe'91 multisensor airborne campaign data collected over the Orgeval French site. Classification results using different combinations of sensors (TMS and AirSAR) or wavelengths (L- and C-bands) are compared. Performance of data fusion is evaluated in terms of identification of land cover types. The best results are obtained when all three data sets are used. Furthermore, some other combinations of data are tried, and their ability to discriminate between the different land cover types is quantified

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A series of novel poly(ester-carbonate)s bearing pendant allyl ester groups P(LA-co-MAC)s were prepared by ring-opening copolymerization Of L-lactide (LA) and 5-methyl-5-allyloxycarbonyl-1,3-dioxan-2-one (MAC) with diethyl zinc (ZnEt2) as initiator. NMR analysis investigated the microstructure of the copolymer. DSC results indicated that the copolymers displayed a single glass-transition temperature (T-g), which was indicative of a random copolymer, and the Tg decreased with increasing carbonate content in the copolymer.

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A biodegradable amphiphilic block copolymer, PEG-b-P(LA-co-MAC), was used to prepare spherical micelles consisting of a hydrophobic P(LA-co-MAC) core and a hydrophilic PEG shell. To improve their stability, the micelles were crosslinked by radical polymerization of the double bonds in the hydrophobic blocks. The crosslinked micelles had similar sizes and a narrow size distribution compared to their uncrosslinked precursor. The improved stability of the crosslinked micelles was confirmed by measurements of the CMC and a thermodynamic investigation. These micelles can internalize into Hela cells in vitro as demonstrated by inverted fluorescence microscopy and CLSM. These stabilized nanoscale micelles have potential use in biomedical applications such as drug delivery and disease diagnosis.

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利用改进了的 Mac Diarmid氧化偶联方法合成了苯 /胺封端的苯胺四聚体 .通过对循环伏安曲线的分析 ,给出二聚体经由电化学氧化 -化学偶联成为四聚体的机理 .利用基质辅助激光解吸质谱和红外光谱对产物进行了表征

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无线通信技术在工业网络化控制系统中的应用已成为当今工业领域中的研究热点。然而无线通信技术在恶劣的工业环境中通信质量严重下降,使得现有无线通信技术在工业网络化控制系统中的应用受阻。为此在不断提高和改进无线信号传输性能的同时,更要在控制系统级层面上充分考虑无线通信技术的特点,进行相关系统结构和实时调度机制等方面的改进,以达到使系统产生的通信任务在应用层上得到可靠、实时调度的目的。同时也要从无线网络技术层面上入手,解决上层下达的通信任务在数据链路层中的实时调度问题。要设计适合工业无线网络化控制系统应用特点的MAC协议来有效调度网络所有节点的信息收发,减少高层下达的通信任务在网络中的平均时延,提高吞吐量,进而保证工业无线网络化控制系统的实时性。 因此,本文从工业无线网络化控制系统中的通信任务在数据链路层和应用层上的调度角度出发,以解决、改善工业无线网络化控制系统的实时性和可靠性等性能指标为目的。对工业无线网络化控制系统的结构、应用层调度策略和优化以及数据链路层中的MAC协议进行了系统的研究。主要工作和贡献有以下几点: (1)对工业网络化控制系统的基本问题和引入无线通信技术后产生的问题进行了探讨。在定性分析了工业环境对无线通信的影响及要求的同时,又推导出了无线通信的链路预算模型,并利用Matlab对该预算模型进行了建模,计算出了在工业级噪声指数和工业要求的误码率下,IEEE802.11b和IEEE802.15.4两大主流无线通信技术的链路预算情况及具体的量化数据。 (2)提出了工业无线网络化控制系统的双频二级拓扑结构和多路径传输机制。利用了无线信道特点和路径冗余优势,在系统级上改进了目前无线通信技术在工业网络化控制系统中的应用模式,部分缓解了无线通信技术在工业恶劣环境中的实时性和可靠性问题。为工业无线网络化控制系统结构的设计做了有益的尝试。同时,首次将DS-UWB技术应用于工业网络化控制系统中,设计出了基于该结构的UWB和FF及PROFIBUS的集成方案,为该结构的快速应用提供了有效的途径。 (3)提出了极大容忍无线通信时延的调度算法(GTD)。有效解决了工业无线网络化控制系统中周期性通信任务的实时性问题,部分弥补了因无线网络时延而导致周期性通信任务超时的缺陷。并针对GTD调度算法产生的通信窗口碎片问题进行了优化处理,又提出了面向非周期信息吞吐量最大化的优化调度算法,该算法提高了非周期性通信任务的吞吐量。同时,给出了基于这两种调度算法的非线性规划模型的调度时间表求解方法。 (4)提出了根据通信任务调度时间表进行分配无竞争期的混合CAP和CFP的MAC协议(HAF-MAC)。解决了工业无线网络化控制系统上层下达的周期性通信任务和非周期性通信任务在数据链路层中的实时调度问题,并有效解决了本文提出的应用层调度算法生成的预留时间可能存在浪费的问题。同时,在理论分析了HAF-MAC协议时隙利用率的基础上,提出了基于时隙的HAF-MAC(TSHAF-MAC)协议。TSHAF-MAC协议比HAF-MAC协议提高了时隙利用率,使吞吐量和平均延时得到了进一步改善,进而提高了非周期性通信任务的实时性。最后,对这两个协议进行了仿真建模与验证,进而较系统地解决了工业无线网络化控制系统中的通信任务的实时调度问题。 (5)分别将论文中的第三章和第四章的部分研究成果,在本人博士研究阶段研发的无线智能照明控制系统这一物理实验平台上进行了一定的验证。

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Present study consists of two experiments. In the first experiment, the relationship between psycho-behavioral factors, immune function and the stage of breast cancer was investigated. Fifty six postoperated hospitalized breast cancer patients with radiotherapy were used as the subjects. EPQ and MAC questionnaires were used to assess the patients' psycho-behavioral factors. Blood NK activation level and saliva IgA level were determined as the assessment of their immune function. It was found that the late stage breast cancer patients were more stable but more anxious in emotion. Patients with extrovert personality had higher NK activation and higher fighting spirit than did the patients with introvert personality. The patients with more fatalism had higher levels of saliva IgA and NK activation than did the patients with less fatalism. It was also found that the higher the level of saliva IgA, the higher the level of fighting spirit. In the second experiment, the effect of psycho-behavioral intervention on the immune function and the emotional state of these patients was studied. It was found that the psycho-behavioral intervention significantly increased the level of NK activation and tended to decrease the level of anxious preoccupation. The number of the patients who had to use medicine to increase peripheral blood white cells during radiotherapy was significantly decreased in patients with psycho-behavioral therapy when compared with the control group. Collectively, the data suggested that the immune function, cancer stage were related to the patients' psycho-behavioral factors and the psycho-behavioral intervention could improve the patients' immune function and emotional state.

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This report mainly summarizes the Project MAC A.I. Group work between July 1968 and June 1969 but covers some work up to February 1970. The work on computer vision is described in detail. This summary should be read in conjunction with last year's A.I. Group Report which is included at the end of this Memo.

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For the design of affinity membranes, protein adsorption in membrane affinity chromatography (MAC) was studied by frontal analysis. According to fast mass transfer, small thickness of affinity membranes and high affinity between the protein and the ligand, an ideal adsorption (IA) model was proposed for MAC and was used together with equilibrium-dispersive (E-D) model to describe the adsorption of bovine serum albumin (BSA) onto cellulose diacetate/polyethyleneimine (CA/PEI) blend membranes with and without Cu2+ chelating. E-D model was found to better describe the initial region of experimental breakthrough curves. The influence of axial dispersion was revealed and it showed the importance of design of the module to homogenously distribute feed solution. IA model was found to be better for the whole experimental breakthrough curve. According to it, the capacity of affinity membranes and the specificity of the interaction are of equal importance for the design of affinity membranes. An optimum feed concentration was also found in the operation of MAC. The discrepancy between experimental optimum feed concentrations and predicted ones from IA model may be due to the ignorance of some experimental effects such as axial dispersion.