Assessing the damming effects on runoff using a multiple linear regression model: A case study of the Manwan Dam on the Lancang River

AbstractThe Lancang River in Yunnan Province, with a length of 1170km and a 1780-m drop from northwest to southeast, is the most controversial river in southwest China because 14 cascade hydropower stations have been planned on the main waterway. The Manwan Dam, the first of the 14 dams, began operating in 1993, and the associated downstream runoff may have been affected by its construction. To assess this impact, we first investigated the relationships between monthly runoff observed from the Gajiu station and meteorological data obtained from four meteorological gauging stations with a time-lag of 0-3 months over the pre-dam period (1957-2000). Second, we established and validated a multiple linear regression equation employing monthly meteorological and hydrological data during the pre-dam period. Finally, we simulated the monthly runoff after dam construction (1993-2000) using the established equations and assessed the impact of dam construction on runoff by comparing the observed actual monthly runoff with the simulated monthly runoff. Our results suggested a very high hydro-meteorological correlation for the pre-dam period, which opened up the possibility of runoff forecasting. Further, the multiple linear regression equation displayed good simulation performance as coefficient of determination (R2) and the Nash-Suttcliffe coefficient (NS) reached 0.84 and 0.82 respectively. By comparing the observed and the predicted monthly runoff, we found that construction of the Manwan Dam caused a visible disturbance on monthly runoff that, with the disturbance value, displayed a multi-peak fluctuation of up-down variation in the annual hydrologic regime circl

Angular distribution of N-doped carbon nanotubes in alumina membrane channels : A high-energy X-ray diffraction study

An alignment study of multi-wall N-doped carbon nanotubes prepared by a template pyrolytic carbon deposition method inside channels of an alumina membrane has been performed using high-energy X-ray diffraction on the ID15B beamline at the European Synchrotron Radiation Facility (ESRF, Grenoble). The two-dimensional diffraction pattern of the deposited carbon nanotubes, recorded directly, within the alumina membrane, using an image plate detector, exhibits two non-continuous arcs corresponding to the 002 graphitic reflection. The following values of the angle between the axis of the carbon nanotubes lying along the membrane channels and the incident beam were taken for five positions: 0±, 30±, 45±, 60± and 90±. The anisotropic scattering distribution of the two-dimensional patterns indicates an orientational alignment of the nanotubes. The one-dimensional intensity patterns obtained by scanning around the circumference of the (0 0 2) ring have allowed an estimation of the angular distribution of the nanotubes axes

Vortex structure in d-density wave scenario of pseudogap

We investigate the vortex structure assuming the d-density wave scenario of the pseudogap. We discuss the profiles of the order parameters in the vicinity of the vortex, effective vortex charge and the local density of states. We find a pronounced modification of these quantities when compared to a purely superconducting case. Results have been obtained for a clean system as well as in the presence of a nonmagnetic impurity. We show that the competition between superconductivity and the density wave may explain some experimental data recently obtained for high-temperature superconductors. In particular, we show that the d-density wave scenario explains the asymmetry of the gap observed in the vicinity of the vortex core.Comment: 8 pages, 10 figure

Optical Sum Rule in Finite Bands

In a single finite electronic band the total optical spectral weight or optical sum carries information on the interactions involved between the charge carriers as well as on their band structure. It varies with temperature as well as with impurity scattering. The single band optical sum also bears some relationship to the charge carrier kinetic energy and, thus, can potentially provide useful information, particularly on its change as the charge carriers go from normal to superconducting state. Here we review the considerable advances that have recently been made in the context of high $T_c$ oxides, both theoretical and experimental.Comment: Review article accepted for publication in J. Low Temp. Phys. 29 pages, 33 figure

Partial Wave Analysis of J/ψ→γ(K+K−π+π−)J/\psi \to \gamma (K^+K^-\pi^+\pi^-)

BES data on $J/\psi \to \gamma (K^+K^-\pi^+\pi^-)$ are presented. The $K^*\bar K^*$ contribution peaks strongly near threshold. It is fitted with a broad $0^{-+}$ resonance with mass $M = 1800 \pm 100$ MeV, width $\Gamma = 500 \pm 200$ MeV. A broad $2^{++}$ resonance peaking at 2020 MeV is also required with width $\sim 500$ MeV. There is further evidence for a $2^{-+}$ component peaking at 2.55 GeV. The non-$K^*\bar K^*$ contribution is close to phase space; it peaks at 2.6 GeV and is very different from $K^{*}\bar{K^{*}}$.Comment: 15 pages, 6 figures, 1 table, Submitted to PL

Single Spin Asymmetry ANA_N in Polarized Proton-Proton Elastic Scattering at s=200\sqrt{s}=200 GeV

We report a high precision measurement of the transverse single spin asymmetry $A_N$ at the center of mass energy $\sqrt{s}=200$ GeV in elastic proton-proton scattering by the STAR experiment at RHIC. The $A_N$ was measured in the four-momentum transfer squared $t$ range $0.003 \leqslant |t| \leqslant 0.035$ \GeVcSq, the region of a significant interference between the electromagnetic and hadronic scattering amplitudes. The measured values of $A_N$ and its $t$-dependence are consistent with a vanishing hadronic spin-flip amplitude, thus providing strong constraints on the ratio of the single spin-flip to the non-flip amplitudes. Since the hadronic amplitude is dominated by the Pomeron amplitude at this $\sqrt{s}$, we conclude that this measurement addresses the question about the presence of a hadronic spin flip due to the Pomeron exchange in polarized proton-proton elastic scattering.Comment: 12 pages, 6 figure

High pTp_{T} non-photonic electron production in pp+pp collisions at s\sqrt{s} = 200 GeV

We present the measurement of non-photonic electron production at high transverse momentum ($p_T >$ 2.5 GeV/$c$) in $p$ + $p$ collisions at $\sqrt{s}$ = 200 GeV using data recorded during 2005 and 2008 by the STAR experiment at the Relativistic Heavy Ion Collider (RHIC). The measured cross-sections from the two runs are consistent with each other despite a large difference in photonic background levels due to different detector configurations. We compare the measured non-photonic electron cross-sections with previously published RHIC data and pQCD calculations. Using the relative contributions of B and D mesons to non-photonic electrons, we determine the integrated cross sections of electrons ($\frac{e^++e^-}{2}$) at 3 GeV/$c < p_T <~$10 GeV/$c$ from bottom and charm meson decays to be ${d\sigma_{(B\to e)+(B\to D \to e)} \over dy_e}|_{y_e=0}$ = 4.0$\pm0.5$({\rm stat.})$\pm1.1$({\rm syst.}) nb and ${d\sigma_{D\to e} \over dy_e}|_{y_e=0}$ = 6.2$\pm0.7$({\rm stat.})$\pm1.5$({\rm syst.}) nb, respectively.Comment: 17 pages, 17 figure

Evolution of the differential transverse momentum correlation function with centrality in Au+Au collisions at sNN=200\sqrt{s_{NN}} = 200 GeV

We present first measurements of the evolution of the differential transverse momentum correlation function, {\it C}, with collision centrality in Au+Au interactions at $\sqrt{s_{NN}} = 200$ GeV. {\it C} exhibits a strong dependence on collision centrality that is qualitatively similar to that of number correlations previously reported. We use the observed longitudinal broadening of the near-side peak of {\it C} with increasing centrality to estimate the ratio of the shear viscosity to entropy density, $\eta/s$, of the matter formed in central Au+Au interactions. We obtain an upper limit estimate of $\eta/s$ that suggests that the produced medium has a small viscosity per unit entropy.Comment: 7 pages, 4 figures, STAR paper published in Phys. Lett.

Ultra violet sensors based on nanostructured ZnO spheres in network of nanowires: a novel approach

The ZnO nanostructures consisting of micro spheres in a network of nano wires were synthesized by direct vapor phase method. X-ray Photoelectron Spectroscopy measurements were carried out to understand the chemical nature of the sample. ZnO nanostructures exhibited band edge luminescence at 383 nm. The nanostructure based ZnO thin films were used to fabricate UV sensors. The photoresponse measurements were carried out and the responsivity was measured to be 50 mA W−1. The rise and decay time measurements were also measured