| 1. |
- Abt, I, et al.
(författare)
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Inclusive V-0 production cross sections from 920 GeV fixed target proton-nucleus collisions
- 2003
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Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 29:2, s. 181-190
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Tidskriftsartikel (refereegranskat)abstract
- Inclusive differential cross sections dsigma(pA)/dx(F) and dsigma(pA)/dp(t)(2) for the production of K-S(0), Lambda, and (&ULambda;) over bar particles are measured at HERA in proton-induced reactions on C, Al, Ti, and W targets. The incident beam energy is 920 GeV, corresponding to roots = 41.6 GeV in the proton-nucleon system. The ratios of differential cross sections dsigma(pA)(K-S(0))/dsigma(pA)(Lambda) and dsigma(pA)((&ULambda;) over bar)/dsigma(pA) (Lambda) are measured to be 6.2 +/- 0.5 and 0.66 +/- 0.07, respectively, for x(F) approximate to -0.06. No significant dependence upon the target material is observed. Within errors, the slopes of the transverse momentum distributions da,Ald t also show no significant dependence upon the target material. The dependence of the extrapolated total cross sections sigma(pA) on the atomic mass A of the target material is discussed, and the deduced cross sections per nucleon sigma(pN) are compared with results obtained at other energies.
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| 2. |
- Abt, I, et al.
(författare)
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Measurement of the b(b)over-bar production cross section in 920 GeV fixed-target proton-nucleus collisions
- 2003
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Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 26:3, s. 345-355
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Tidskriftsartikel (refereegranskat)abstract
- Using the HERA-B detector, the b (b) over bar production cross section has been measured in 920 GeV proton collisions on carbon and titanium targets. The b (b) over bar production was tagged via inclusive bottom quark decays into J/psi by exploiting the longitudinal separation of J/psi --> l(+)l(-) decay vertices from the primary proton-nucleus interaction. Both e(+)e(-) and mu(+)mu(-) channels have been reconstructed and the combined analysis yields the cross section sigma(b (b) over bar) = 32(-12)(+14)(stat) (+6)(-7)(sys) nb/nucleon.
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| 3. |
- Liu, T. B., et al.
(författare)
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Synthesis, structures and electrochemical properties of nitro- and amino-functionalized diiron azadithiolates as active site models of Fe-only hydrogenases
- 2004
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Ingår i: Chemistry - A European Journal. - : Wiley. - 0947-6539 .- 1521-3765. ; 10:18, s. 4474-4479
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Tidskriftsartikel (refereegranskat)abstract
- Complex [{(mu-SCH2)(2)N(4-NO2C6H4)}Fe-2(CO)(6)] (4) was prepared by the reaction of the dianionic intermediate [(mu-S)(2)Fe-2(CO)(6)](2-) and N,N-bis(chloromethyl)-4-nitroaniline as a biomimetic model of the active site of Fe-only hydrogenase. The reduction of 4 by Pd-C/H-2 under a neutral condition afforded complex [{(mu-SCH2)(2)N(4-NH2C6H4)}Fe-2(CO)(6)] (5) in 67% yield. Both complexes were characterized by IR, H-1 and C-13 NMR spectroscopy and MS spectrometry. The molecular structure of 4, as determined by X-ray analysis, has a butterfly 2Fe2S core and the aryl group on the bridged-N atom slants to the Fe(2) site. Cyclic voltammograms of 4 and 5 were studied to evaluate their redox properties. It was found that complex 4 catalyzed electrochemical proton reduction in the presence of acetic acid. A plausible mechanism of the electrocatalytic proton reduction is discussed.
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| 4. |
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| 5. |
- Belonoshko, Anatoly B., et al.
(författare)
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First-principles study of hydrogen diffusion in α-Al 2O3 and liquid alumina
- 2004
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Ingår i: Physical Review B Condensed Matter. - 0163-1829 .- 1095-3795. ; 69:2, s. 243021-243026
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Tidskriftsartikel (refereegranskat)abstract
- We have studied the energetics and mobility of neutral hydrogen in alumina Al2O3 using ab initio density-functional calculations. The mobility of hydrogen was studied in corundum (α-Al2O 3) as well as in liquid alumina. Using both static as well as molecular-dynamics calculations, and applying classical transition state theory, we derive the temperature-dependent diffusivity of hydrogen in α-Al 2O3 as D(T)=(21.7 × 10-8 m 2/s)exp(-1.24 eV/kT). The corresponding diffusivity of hydrogen in liquid/amorphous alumina, derived directly from ab initio molecular dynamics calculations, is D(T)=(8.71 × 10-7 m2/s)exp(-0.91 eV/kT). The computed diffusivity compares very well to experimental data. We conclude that diffusion of neutral hydrogen through the bulk of alumina is a good approximation of the mechanism for hydrogen mobility in corrosion scales. The representation of grain-boundary structures by amorphous alumina is, probably, realistic at higher temperatures.
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| 6. |
- Cho, Eunyoung, et al.
(författare)
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Alcohol intake and colorectal cancer : a pooled analysis of 8 cohort studies
- 2004
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Ingår i: Annals of Internal Medicine. - : American College of Physicians. - 0003-4819 .- 1539-3704. ; 140:8, s. 603-613
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Epidemiologic studies have generally reported positive associations between alcohol consumption and risk for colorectal cancer. However, findings related to specific alcoholic beverages or different anatomic sites in the large bowel have been inconsistent. OBJECTIVE: To examine the relationship of total alcohol intake and intake from specific beverages to the incidence of colorectal cancer and to evaluate whether other potential risk factors modify the association. DESIGN: Pooled analysis of primary data from 8 cohort studies in 5 countries. SETTING: North America and Europe. PARTICIPANTS: 489,979 women and men with no history of cancer other than nonmelanoma skin cancer at baseline. MEASUREMENTS: Alcohol intake was assessed in each study at baseline by using a validated food-frequency questionnaire. RESULTS: During a maximum of 6 to 16 years of follow-up across the studies, 4687 cases of colorectal cancer were documented. In categorical analyses, increased risk for colorectal cancer was limited to persons with an alcohol intake of 30 g/d or greater (approximately > or =2 drinks/d), a consumption level reported by 4% of women and 13% of men. Compared with nondrinkers, the pooled multivariate relative risks were 1.16 (95% CI, 0.99 to 1.36) for persons who consumed 30 to less than 45 g/d and 1.41 (CI, 1.16 to 1.72) for those who consumed 45 g/d or greater. No significant heterogeneity by study or sex was observed. The association was evident for cancer of the proximal colon, distal colon, and rectum. No clear difference in relative risks was found among specific alcoholic beverages. LIMITATIONS: The study included only one measure of alcohol consumption at baseline and could not investigate lifetime alcohol consumption, alcohol consumption at younger ages, or changes in alcohol consumption during follow-up. It also could not examine drinking patterns or duration of alcohol use. CONCLUSIONS: A single determination of alcohol intake correlated with a modest relative elevation in colorectal cancer rate, mainly at the highest levels of alcohol intake.
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| 7. |
- Dong, B.G., et al.
(författare)
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Shape coexistence and band termination in 131La
- 2002
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Ingår i: Gaoneng Wuli Yu He Wuli. - 0254-3052. ; 26:3, s. 266-272
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Tidskriftsartikel (refereegranskat)abstract
- The configuration-dependent cranked Nilsson-Strutinsky model is used to study the band structures in La-131. Shape coexistence and band termination are investigated for several configurations. The calculations indicate that La-131 is a gamma-soft nucleus. The theoretical results are compared with experimental data. The calculated pi( h(11/2))(2) circle times nu( h(11/2))(8) configuration with (pi, alpha) = ( +, - 1/2) shows very good agreement with the experimental band observed to highest spin. The termination of this band is not favored, i. e. a relatively large energy is required to build the highest spin states in the band.
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| 8. |
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| 9. |
- Parry, C. M., et al.
(författare)
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First evidence for smooth band termination in valence space in the mass 130 region : Spectroscopy of 127La
- 2000
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Ingår i: Physical Review C - Nuclear Physics. - 0556-2813. ; 61:2, s. 213031-213035
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Tidskriftsartikel (refereegranskat)abstract
- High spin states in 127La have been studied using the 32S(100Mo,p4n) reaction at a beam energy of 155 MeV. Gamma rays were detected using the EUROBALL III spectrometer. One of the side bands in 127La is observed to be populated to a spin of 83/2+. These data are compared with cranked Nilsson-Strutinski calculations which suggest that the structure is a smoothly terminating band, in valence space, based upon a π[(g7/2d5/2)5(h11/2)2]⊗ ν[(g7/2d5/2)12(h11/2)6(d3/2s1/2)2] configuration, which can carry a maximum spin of 47.5ℏ. This is the first identification of such a structure in this mass region.
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| 10. |
- Robinson, SD, et al.
(författare)
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High-spin structures and band termination effects in Cd-104
- 2002
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Ingår i: Journal of Physics G: Nuclear and Particle Physics. - : IOP Publishing. - 0954-3899. ; 28:6, s. 1415-1431
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Tidskriftsartikel (refereegranskat)abstract
- High-spin states in the neutron-deficient isotope Cd-104 were populated using the Cr-50(Ni-58,4p)Cd-104 reaction at a beam energy of 250 MeV The level scheme has been extended using triple gamma-ray coincidences to a spin of 29h and an excitation energy of 18.2 MeV. Several collective structures involving the excitation of h(11/2) neutrons have been observed to spins approaching 30h. The high-spin structure has been compared to the results of cranked Nilsson-Strutinsky calculations.
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