Der ProLan-X - Sprachreport

Bei der Realisierung großer Software-Projekte treten immer wieder Probleme auf, was die Koordination der Mitarbeiter, die Ausnutzung der vorhandenen Ressourcen und nicht zuletzt die Qualität der erzeugten Produkte angeht. Um die Vorgänge bei der Produktion von Software durchschaubarer und verständlicher zu machen, versucht man, diese aus der Sicht von Meta-Modellen zu beschreiben. Dabei fließen die individuellen Rahmenbedingungen einer jeden Entwicklungsumgebung ein; die vorhandenen Ressourcen werden ebenso modellien wie die durchzuführenden Tätigkeiten und ihre Abhängigkeiten. Die Beschreibungssprache für den Software-Prozeß ProLan-X dient der (konkreten) Beschreibung der Bestandteile des Meta-Modells MoMo, das ebenfalls in dieser Arbeitsgruppe entwickelt wurde [Schramm]. Die am Projekt beteiligten Personen, Hardware- und Software-Ressourcen und ihre Aufgaben werden in möglichst natürlicher Weise verhaltensorientien beschrieben. Aus dieser Beschreibung kann eine Ablaufumgebung generien werden, die die Durchführung des Projekts unterstützt und protokolliert. Der vorliegende Bericht faßt die Eigenschaften der Sprache ProLan-X zusammen und erläuten ihre Verwendung. Er setzt das MoMo-Modell als bekannt voraus

Microwave-induced water flow in a microchannel built on a coplanar waveguide

We present experimental and numerical investigations of water flow in a microsystem induced by microwave electric fields. Microwave dielectric heating induces gradients of temperature which produce spatial variations in mass density and dielectric permittivity that lead to buoyancy and dielectric forces in the liquid, respectively. The experimental system consists of a microchannel, filled with water, which is built on top of a coplanar waveguide operating in the fundamental transversal electromagnetic (TEM) mode at frequencies in the range 1–4 GHz. The flow originated by standing waves is studied. Maxima and minima of electric field amplitude lead to maxima and minima of fluid flow. This observation allows us to measure the TEM wavelength and good agreement is found with the theoretical results for the TEM mode inside the microchannel. We also present three dimensional finite-element calculations of the electric, temperature and fluid velocity fields in the microchannel. In a first approach, the calculations are performed using the equations in the limit of small temperature variations, which allows us to decouple the electrical, mechanical and thermal equations. These calculations show a good agreement with the velocity profiles. Subsequently, the effect of considering finite increments of temperature is taken into account and the new numerical results improve the quantitative comparison with experimental velocities.Ministerio de Gobierno español MEC-FIS2006-03645Junta de Andalucía-P09-FQM-458

Nickel: A very fast diffuser in silicon

Nickel is increasingly used in both IC and photovoltaic device fabrication, yet it has the potential to create highly recombination-active precipitates in silicon. For nearly three decades, the accepted nickel diffusivity in silicon has been DNi(T)=2.3×10exp−3 exp(−0.47 eV/kBT) cm2/s, a surprisingly low value given reports of rapid nickel diffusion in industrial applications. In this paper, we employ modern experimental methods to measure the higher nickel diffusivity DNi(T)=(1.69±0.74)×10exp−4 exp(−0.15±0.04 eV/kBT)  cm2/s. The measured activation energy is close to that predicted by first-principles theory using the nudged-elastic-band method. Our measured diffusivity of nickel is higher than previously published values at temperatures below 1150 °C, and orders of magnitude higher when extrapolated to room temperature.Peer reviewe

Bose-Einstein correlations of same-sign charged pions in the forward region in pp collisions at √s=7 TeV

Bose-Einstein correlations of same-sign charged pions, produced in protonproton collisions at a 7 TeV centre-of-mass energy, are studied using a data sample collected by the LHCb experiment. The signature for Bose-Einstein correlations is observed in the form of an enhancement of pairs of like-sign charged pions with small four-momentum difference squared. The charged-particle multiplicity dependence of the Bose-Einstein correlation parameters describing the correlation strength and the size of the emitting source is investigated, determining both the correlation radius and the chaoticity parameter. The measured correlation radius is found to increase as a function of increasing charged-particle multiplicity, while the chaoticity parameter is seen to decreas

Study of charmonium production in b -hadron decays and first evidence for the decay Bs0

Using decays to φ-meson pairs, the inclusive production of charmonium states in b-hadron decays is studied with pp collision data corresponding to an integrated luminosity of 3.0 fb−1, collected by the LHCb experiment at centre-of-mass energies of 7 and 8 TeV. Denoting byBC ≡ B(b → C X) × B(C → φφ) the inclusive branching fraction of a b hadron to a charmonium state C that decays into a pair of φ mesons, ratios RC1C2 ≡ BC1 /BC2 are determined as Rχc0ηc(1S) = 0.147 ± 0.023 ± 0.011, Rχc1ηc(1S) =0.073 ± 0.016 ± 0.006, Rχc2ηc(1S) = 0.081 ± 0.013 ± 0.005,Rχc1 χc0 = 0.50 ± 0.11 ± 0.01, Rχc2 χc0 = 0.56 ± 0.10 ± 0.01and Rηc(2S)ηc(1S) = 0.040 ± 0.011 ± 0.004. Here and below the first uncertainties are statistical and the second systematic.Upper limits at 90% confidence level for the inclusive production of X(3872), X(3915) and χc2(2P) states are obtained as RX(3872)χc1 < 0.34, RX(3915)χc0 < 0.12 andRχc2(2P)χc2 < 0.16. Differential cross-sections as a function of transverse momentum are measured for the ηc(1S) andχc states. The branching fraction of the decay B0s → φφφ is measured for the first time, B(B0s → φφφ) = (2.15±0.54±0.28±0.21B)×10−6. Here the third uncertainty is due to the branching fraction of the decay B0s → φφ, which is used for normalization. No evidence for intermediate resonances is seen. A preferentially transverse φ polarization is observed.The measurements allow the determination of the ratio of the branching fractions for the ηc(1S) decays to φφ and p p asB(ηc(1S)→ φφ)/B(ηc(1S)→ p p) = 1.79 ± 0.14 ± 0.32

Measurement of the inelastic pp cross-section at a centre-of-mass energy of 13TeV

The cross-section for inelastic proton-proton collisions at a centre-of-mass energy of 13TeV is measured with the LHCb detector. The fiducial cross-section for inelastic interactions producing at least one prompt long-lived charged particle with momentum p &gt; 2 GeV/c in the pseudorapidity range 2 &lt; η &lt; 5 is determined to be ϭ acc = 62:2 ± 0:2 ± 2:5mb. The first uncertainty is the intrinsic systematic uncertainty of the measurement, the second is due to the uncertainty on the integrated luminosity. The statistical uncertainty is negligible. Extrapolation to full phase space yields the total inelastic proton-proton cross-section ϭ inel = 75:4 ± 3:0 ± 4:5mb, where the first uncertainty is experimental and the second due to the extrapolation. An updated value of the inelastic cross-section at a centre-of-mass energy of 7TeV is also reported

Hetero-type dual photoanodes for unbiased solar water splitting with extended light harvesting

Metal oxide semiconductors are promising photoelectrode materials for solar water splitting due to their robustness in aqueous solutions and low cost. Yet, their solar-to-hydrogen conversion efficiencies are still not high enough for practical applications. Here we present a strategy to enhance the efficiency of metal oxides, hetero-type dual photoelectrodes, in which two photoanodes of different bandgaps are connected in parallel for extended light harvesting. Thus, a photoelectrochemical device made of modified BiVO4 and alpha-Fe2O3 as dual photoanodes utilizes visible light up to 610nm for water splitting, and shows stable photocurrents of 7.0 +/- 0.2 mA cm(-2) at 1.23 V-RHE under 1 sun irradiation. A tandem cell composed with the dual photoanodes-silicon solar cell demonstrates unbiased water splitting efficiency of 7.7%. These results and concept represent a significant step forward en route to the goal of &gt;10% efficiency required for practical solar hydrogen production.ope

Updated Determination of D⁰–D¯⁰Mixing and CP Violation Parameters with D⁰→K⁺π⁻ Decays

We report measurements of charm-mixing parameters based on the decay-time-dependent ratio of D⁰→K⁺π⁻ to D⁰→K⁻π⁺ rates. The analysis uses a data sample of proton-proton collisions corresponding to an integrated luminosity of 5.0  fb⁻¹ recorded by the LHCb experiment from 2011 through 2016. Assuming charge-parity (CP) symmetry, the mixing parameters are determined to be x′²=(3.9±2.7)×10⁻⁵, y′=(5.28±0.52)×10⁻³, and R[subscript D]=(3.454±0.031)×10⁻³. Without this assumption, the measurement is performed separately for D⁰ and D[over ¯]⁰ mesons, yielding a direct CP-violating asymmetry A[subscript D]=(-0.1±9.1)×10⁻³, and magnitude of the ratio of mixing parameters 1.00<|q/p|<1.35 at the 68.3% confidence level. All results include statistical and systematic uncertainties and improve significantly upon previous single-measurement determinations. No evidence for CP violation in charm mixing is observed

Observation of D⁰ Meson Decays to Π⁺π⁻μ⁺μ⁻ and K⁺K⁻μ⁺μ⁻ Final States

The first observation of the D⁰→π⁺π⁻μ⁺μ⁻ and D⁰→K⁺K⁻μ⁺μ⁻ decays is reported using a sample of proton-proton collisions collected by LHCb at a center-of-mass energy of 8 TeV, and corresponding to 2  fb⁻¹ of integrated luminosity. The corresponding branching fractions are measured using as normalization the decay D⁰→K⁻π⁺[μ⁺μ⁻][subscript ρ⁰/ω], where the two muons are consistent with coming from the decay of a ρ⁰ or ω meson. The results are B(D⁰→π⁺π⁻μ⁺μ⁻)=(9.64±0.48±0.51±0.97)×10⁻⁷ and B(D⁰→K⁺K⁻μ⁺μ⁻)=(1.54±0.27±0.09±0.16)×10⁻⁷, where the uncertainties are statistical, systematic, and due to the limited knowledge of the normalization branching fraction. The dependence of the branching fraction on the dimuon mass is also investigated

Measurement of CP observables in B± → D(⁎)K± and B± → D(⁎)π± decays

Measurements of CP observables in B ± →D (⁎) K ± and B ± →D (⁎) π ± decays are presented, where D (⁎) indicates a neutral D or D ⁎ meson that is an admixture of D (⁎)0 and D¯ (⁎)0 states. Decays of the D ⁎ meson to the Dπ 0 and Dγ final states are partially reconstructed without inclusion of the neutral pion or photon, resulting in distinctive shapes in the B candidate invariant mass distribution. Decays of the D meson are fully reconstructed in the K ± π ∓ , K + K − and π + π − final states. The analysis uses a sample of charged B mesons produced in pp collisions collected by the LHCb experiment, corresponding to an integrated luminosity of 2.0, 1.0 and 2.0 fb −1 taken at centre-of-mass energies of s=7, 8 and 13 TeV, respectively. The study of B ± →D ⁎ K ± and B ± →D ⁎ π ± decays using a partial reconstruction method is the first of its kind, while the measurement of B ± →DK ± and B ± →Dπ ± decays is an update of previous LHCb measurements. The B ± →DK ± results are the most precise to date