Azimuthally sensitive Hanbury Brown-Twiss interferometry in Au+Au collisions at sqrt(s_{NN}) = 200 GeV

We present the results of a systematic study of the shape of the pion distribution in coordinate space at freeze-out in Au+Au collisions at RHIC using two-pion Hanbury Brown-Twiss (HBT) interferometry. Oscillations of the extracted HBT radii vs. emission angle indicate sources elongated perpendicular to the reaction plane. The results indicate that the pressure and expansion time of the collision system are not sufficient to completely quench its initial shape.Comment: 6 pages, 4 figures, published versio

Phi meson production in Au+Au and p+p collisions at sqrt (s)=200 GeV

We report the STAR measurement of Phi meson production in Au+Au and p+p collisions at sqrt (s)=200 GeV. Using the event mixing technique, the Phi spectra and yields are obtained at mid-rapidity for five centrality bins in Au+Au collisions and for non-singly-diffractive p+p collisions. It is found that the Phi transverse momentum distributions from Au+Au collisions are better fitted with a single-exponential while the p+p spectrum is better described by a double-exponential distribution. The measured nuclear modification factors indicate that Phi production in central Au+Au collisions is suppressed relative to peripheral collisions when scaled by the number of binary collisions. The systematics of versus centrality and the constant Phi/K- ratio versus beam species, centrality, and collision energy rule out kaon coalescence as the dominant mechanism for Phi production.Comment: 6 pages, 3 figures, submitted to Phys. Rev. Let

ρ\u3csup\u3e0\u3c/sup\u3e production and possible modification in Au + Au and p + p collisions at √s\u3csub\u3eNN\u3c/sub\u3e = 200 GeV

We report results on ρ(770)0→π+π− production at midrapidity in p+p and peripheral Au+Au collisions at √sNN=200  GeV. This is the first direct measurement of ρ(770)0→π+π− in heavy-ion collisions. The measured ρ0 peak in the invariant mass distribution is shifted by ∼40  MeV/c2 in minimum bias p+p interactions and ∼70  MeV/c2 in peripheral Au+Au collisions. The ρ0 mass shift is dependent on transverse momentum and multiplicity. The modification of the ρ0 meson mass, width, and shape due to phase space and dynamical effects are discussed

Distributions of Charged Hadrons Associated with High Transverse Momentum Particles in pp and Au+Au Collisions at √s\u3csub\u3eNN\u3c/sub\u3e = 200 GeV

Charged hadrons in 0.15⊥\u3c4  GeV/c associated with particles of ptrig⊥\u3e4  GeV/c are reconstructed in pp and Au+Au collisions at √sNN=200  GeV. The associated multiplicity and p⊥magnitude sum are found to increase from pp to central Au+Au collisions. The associated p⊥distributions, while similar in shape on the nearside, are significantly softened on the awayside in central Au+Au relative to pp and not much harder than that of inclusive hadrons. The results, consistent with jet quenching, suggest that the awayside fragments approach equilibration with the medium traversed

rho(0) production and possible modification in Au+Au and p+p collisions at root S-NN=200 GeV

We report results on rho(770)(0)-->pi(+)pi(-) production at midrapidity in p+p and peripheral Au+Au collisions at roots(NN)=200 GeV. This is the first direct measurement of rho(770)(0)-->pi(+)pi(-) in heavy-ion collisions. The measured rho(0) peak in the invariant mass distribution is shifted by similar to40 MeV/c(2) in minimum bias p+p interactions and similar to70 MeV/c(2) in peripheral Au+Au collisions. The rho(0) mass shift is dependent on transverse momentum and multiplicity. The modification of the rho(0) meson mass, width, and shape due to phase space and dynamical effects are discussed

Distributions of charged hadrons associated with high transverse momentum particles in pp and Au plus Au collisions at root(S)(NN)=200 GeV

Charged hadrons in 0.15 4 GeV/c are reconstructed in pp and Au+Au collisions at root s(NN)=200 GeV. The associated multiplicity and p(perpendicular to) magnitude sum are found to increase from pp to central Au+Au collisions. The associated p(perpendicular to) distributions, while similar in shape on the nearside, are significantly softened on the awayside in central Au+Au relative to pp and not much harder than that of inclusive hadrons. The results, consistent with jet quenching, suggest that the awayside fragments approach equilibration with the medium traversed

Research and Design of a Routing Protocol in Large-Scale Wireless Sensor Networks

无线传感器网络，作为全球未来十大技术之一，集成了传感器技术、嵌入式计算技术、分布式信息处理和自组织网技术，可实时感知、采集、处理、传输网络分布区域内的各种信息数据，在军事国防、生物医疗、环境监测、抢险救灾、防恐反恐、危险区域远程控制等领域具有十分广阔的应用前景。 本文研究分析了无线传感器网络的已有路由协议，并针对大规模的无线传感器网络设计了一种树状路由协议，它根据节点地址信息来形成路由，从而简化了复杂繁冗的路由表查找和维护，节省了不必要的开销，提高了路由效率，实现了快速有效的数据传输。 为支持此路由协议本文提出了一种自适应动态地址分配算——ADAR（AdaptiveDynamicAddre...As one of the ten high technologies in the future, wireless sensor network, which is the integration of micro-sensors, embedded computing, modern network and Ad Hoc technologies, can apperceive, collect, process and transmit various information data within the region. It can be used in military defense, biomedical, environmental monitoring, disaster relief, counter-terrorism, remote control of haz...学位：工学硕士院系专业：信息科学与技术学院通信工程系_通信与信息系统学号：2332007115216

Azimuthally sensitive hanbury brown-twiss interferometry in Au+Au collisions at root s(NN)=200 GeV

We present the results of a systematic study of the shape of the pion distribution in coordinate space at freeze-out in Au+Au collisions at BNL RHIC using two-pion Hanbury Brown-Twiss (HBT) interferometry. Oscillations of the extracted HBT radii versus emission angle indicate sources elongated perpendicular to the reaction plane. The results indicate that the pressure and expansion time of the collision system are not sufficient to completely quench its initial shape

Distributions of charged hadrons associated with high transverse momentum particles in pp and Au plus Au collisions at root(S)(NN)=200 GeV

Charged hadrons in 0.15 \u3c p(perpendicular to)\u3c 4 GeV/c associated with particles of p(perpendicular to)(trig)\u3e 4 GeV/c are reconstructed in pp and Au+Au collisions at root s(NN)=200 GeV. The associated multiplicity and p(perpendicular to) magnitude sum are found to increase from pp to central Au+Au collisions. The associated p(perpendicular to) distributions, while similar in shape on the nearside, are significantly softened on the awayside in central Au+Au relative to pp and not much harder than that of inclusive hadrons. The results, consistent with jet quenching, suggest that the awayside fragments approach equilibration with the medium traversed

rho(0) production and possible modification in Au+Au and p+p collisions at root S-NN=200 GeV

We report results on rho(770)(0)--\u3epi(+)pi(-) production at midrapidity in p+p and peripheral Au+Au collisions at roots(NN)=200 GeV. This is the first direct measurement of rho(770)(0)--\u3epi(+)pi(-) in heavy-ion collisions. The measured rho(0) peak in the invariant mass distribution is shifted by similar to40 MeV/c(2) in minimum bias p+p interactions and similar to70 MeV/c(2) in peripheral Au+Au collisions. The rho(0) mass shift is dependent on transverse momentum and multiplicity. The modification of the rho(0) meson mass, width, and shape due to phase space and dynamical effects are discussed