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| 2. |
- Adcox, K, et al.
(författare)
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PHENIX detector overview
- 2003
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Ingår i: Nuclear Instruments & Methods in Physics Research. Section A: Accelerators, Spectrometers, Detectors, and Associated Equipment. - 0167-5087. ; 499:2-3, s. 469-479
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Tidskriftsartikel (refereegranskat)abstract
- The PHENIX detector is designed to perform a broad study of A-A, p-A, and p-p collisions to investigate nuclear matter under extreme conditions. A wide variety of probes, sensitive to all timescales, are used to study systematic variations with species and energy as well as to measure the spin structure of the nucleon. Designing for the needs of the heavy-ion and polarized-proton programs has produced a detector with unparalleled capabilities. PHENIX measures electron and muon pairs, photons, and hadrons with excellent energy and momentum resolution. The detector consists of a large number of subsystems that are discussed in other papers in this volume. The overall design parameters of the detector are presented. (C) 2002 Elsevier Science B.V. All rights reserved.
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| 3. |
- Zhang, L. N., et al.
(författare)
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Triple helix of beta-D-glucan from Lentinus Edodes in 0.5 M NaCl aqueous solution characterized by light scattering
- 2001
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Ingår i: Polymer journal. - : Springer Science and Business Media LLC. - 0032-3896 .- 1349-0540. ; 33:4, s. 317-321
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Tidskriftsartikel (refereegranskat)abstract
- beta-(1 -->3)-D-glucan with (1 -->6) branching (L-FV-I) from Lentinus edodes in water was degraded into seven fractions of different molecular weights by ultrasonic irradiation. Weight-average molecular weight M,, radius of gyration (1/2)(5) and intrinsic viscosity [eta] of the beta -D-glucan and its fractions in 0.5 M NaCl aqueous solution and dimethylsulfoxide (DMSO) were studied by multi-angle laser light scattering (MALLS), GPC combined with MALLS, and viscometry. M, dependence of [eta] for the glucan in 0.5 M NaCl aqueous solution was represented approximately by [eta] =7.69 x 10(-6) M-w(1.32) (cm(3) g(-1)) at M-w from 1.87 X 10(5) to 1.20 X 10(6) at 25 degreesC. GPC chromatograms of the glucans in aqueous solution contained two peaks, a main peak corresponding to triple-stranded chains with molecular weight M-w,M-m, and small second peak corresponding to fragments of single chains with M-w,M-s (about 20 +/-5% content). Analysis of M-w,M-m and (1/2)(z,m) in term of the known theory for wormlike chains yielded 2180 +/- 100 nm(-1), 120 +/- 10 nm and 0.31 nm for molar mass per unit contour length M-L, persistence length q, and contour length h per main-chain glucose residue, respectively, which agree closely with theory data of triple-helical chains and reported parameters for triple-helix schizophyllan in 0.01 M NaOH aqueous solution. The ratios of M-w,M-m, in 0.5 M NaCl to M, in DMSO were calculated to be roughly 3. The predominant species of the glucan in 0.5 M NaCl aqueous solution exist as triple-helical chains with high rigidity, and in DMSO as single-flexible chains.
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| 4. |
- Li, B., et al.
(författare)
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Low-temperature dependence of midinfrared optical constants of lead-germanium-telluride thin film
- 2002
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Ingår i: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 91:6, s. 3556-3561
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Tidskriftsartikel (refereegranskat)abstract
- The design and manufacture of diode lasers for gas analysis or multilayer thin-film optical devices used at low-temperature require the refractive index and the temperature coefficient of IV-VI compound over a significant temperature range. In this article, the refractive index and the absorption coefficient of Pb0.94Ge0.06Te thin film have been determined from transmission spectra measured at temperature between 80 and 300 K in the spectral range of 2.5-8.5 mum by fitting based on a Lorentz-oscillator model. It is found that the maximum refractive index occurs at 150 K, which corresponds to the structural phase transition from rocksalt to rhombohedrally distorted structure and reflects an increase of lattice polarizability. The value of the index of refraction is 5.350-6.000 in the spectral range of 4.0-8.5 mum for all measured temperatures, which reveals that Pb1-xGexTe is a highly refractive infrared material. The temperature coefficient of refractive index, dn/dT, is found to be -0.006-0.002 K-1 in the spectral range of 3.0-8.5 mum for all measured temperature. An empirical formula that fits the temperature coefficient in the spectral range of 4.0-8.5 mum is presented. The dependence of the transmission and absorption spectra on decreasing temperature can be explained by the modification of the energy-band structure due to rhombohedral distortions. The conclusion can be drawn that anomalies corresponding to the ferroelectric phase transition occur in both refractive index and absorption coefficient of Pb1-xGexTe alloy.
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| 5. |
- Scherer, SW, et al.
(författare)
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Human chromosome 7: DNA sequence and biology
- 2003
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Ingår i: Science (New York, N.Y.). - : American Association for the Advancement of Science (AAAS). - 1095-9203 .- 0036-8075. ; 300:5620, s. 767-772
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Tidskriftsartikel (refereegranskat)abstract
- DNA sequence and annotation of the entire human chromosome 7, encompassing nearly 158 million nucleotides of DNA and 1917 gene structures, are presented. To generate a higher order description, additional structural features such as imprinted genes, fragile sites, and segmental duplications were integrated at the level of the DNA sequence with medical genetic data, including 440 chromosome rearrangement breakpoints associated with disease. This approach enabled the discovery of candidate genes for developmental diseases including autism.
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| 6. |
- Zhang, L., et al.
(författare)
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Effects of intense laser irradiation on Raman intensity features of carbon nanotubes
- 2002
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 65:7
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Tidskriftsartikel (refereegranskat)abstract
- The effect of intense laser irradiation on the features of Raman intensity of carbon nanotubes (CNT's) has been examined. The intensity of the D band decreases and the relative intensity between the G peaks changes with increasing laser power density (LPD) and remain unchanged with subsequent decrease in LPD. This behavior is different from the reversible variation of the G band frequency in the same process of power increase and subsequent decrease. It has been demonstrated that such irreversible change in intensity features originates from sample purification. This result suggests a simple and fast CNT purification method using intense laser irradiation.
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| 7. |
- Zhang, Shi-Li, et al.
(författare)
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Abnormal anti-Stokes Raman scattering of carbon nanotubes
- 2002
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 66:3
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Tidskriftsartikel (refereegranskat)abstract
- Abnormal anti-Stokes Raman scattering (AASR) was unambiguously observed in carbon nanotubes (CNT's). In contrast to traditional Raman scattering theory, the absolute value of the Raman frequency of the anti-Stokes peak is not the same as that of the corresponding Stokes peak. It was demonstrated that AASR scattering originates from the unique nanoscale cylindrical structure of CNT's that can be considered naturally as a graphite structure with an intrinsic defect from its rolling. The double-resonance Raman scattering theory was applied to interpret the scattering mechanism of the AASR phenomenon successfully and quantitatively.
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| 8. |
- Adcox, K, et al.
(författare)
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Centrality dependence of the high (PT) charged hadron suppression in Au+Au collisions at root s(NN)=130 GeV
- 2003
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Ingår i: Physics Letters. Section B: Nuclear, Elementary Particle and High-Energy Physics. - 0370-2693. ; 561:1-2, s. 82-92
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Tidskriftsartikel (refereegranskat)abstract
- PHENIX has measured the centrality dependence of charged hadron p(T) spectra from Au +An collisions at root(s)NN = 130 GeV The truncated mean p(T) decreases with centrality for p(T) > 2 GeV/c, indicating an apparent reduction of the contribution from hard scattering to high p(T) hadrdn production. For central collisions the yield at high p(T) is shown to be suppressed compared to binary nucleon-nucleon collision scaling of p + p, data. This suppression is monotonically increasing with centrality, but most of the change occurs below 30% centrality, i.e., for collisions with less than similar to140 participating nucleons. The observed p(T) and centrality dependence is consistent with the particle production predicted by models including hard scattering and subsequent energy loss of the scattered partons in the dense matter created in the collisions. (C) 2003 Published by Elsevier Science B.V.
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| 9. |
- Adcox, K, et al.
(författare)
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Event-by-event fluctuations in mean p(T) and mean E(T) in root s(NN)=130 GeVAu+Au collisions
- 2002
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Ingår i: Physical Review C (Nuclear Physics). - 0556-2813. ; 66:2
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Tidskriftsartikel (refereegranskat)abstract
- Distributions of event-by-event fluctuations of the mean transverse momentum and mean transverse energy near mid-rapidity have been measured in Au+Au collisions at roots(NN)=130 GeV at the Relativistic Heavy-Ion Collider. By comparing the distributions to what is expected for statistically independent particle emission, the magnitude of nonstatistical fluctuations in mean transverse momentum is determined to be consistent with zero. Also, no significant nonrandom fluctuations in mean transverse energy are observed. By constructing a fluctuation model with two event classes that preserve the mean and variance of the semi-inclusive p(T) or e(T) spectra, we exclude a region of fluctuations in roots(NN)=130 GeV Au+Au collisions.
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| 10. |
- Adcox, K, et al.
(författare)
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Flow Measurements via Two-Particle Azimuthal Correlations in Au+Au Collisions at sqrt[sNN]=130 GeV
- 2002
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Ingår i: Physical Review Letters. - 1079-7114. ; 89
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Tidskriftsartikel (refereegranskat)abstract
- Two-particle azimuthal correlation functions are presented for charged hadrons produced in Au+Au collisions at the Relativistic Heavy Ion Collider (sqrt[sNN]=130 GeV). The measurements permit determination of elliptic flow without event-by-event estimation of the reaction plane. The extracted elliptic flow values (v2) show significant sensitivity to both the collision centrality and the transverse momenta of emitted hadrons, suggesting rapid thermalization and relatively strong velocity fields. When scaled by the eccentricity of the collision zone ε, the scaled elliptic flow shows little or no dependence on centrality for charged hadrons with relatively low pT. A breakdown of this ε scaling is observed for charged hadrons with pT >1.0 GeV/c.
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