Synthesis of multi-color luminescent ZnO nanoparticles by ultra-short pulsed laser ablation

Abstract Crystalline ZnO nanoparticles (NPs) are synthesized by ultra-short femtosecond (fs) pulsed laser ablation (PLA) of a zinc plate in deionized water, and are investigated by optical absorption and time resolved luminescence spectra in combination with the morphology and structure analysis. The comparison with previous experiments based on short nanosecond (ns) PLA highlights that pulse duration is a crucial parameter to determine the size and the optical properties of ZnO NPs. While short PLA generates NPs with average size S ‾ of ~ 30 nm, ultrashort PLA allows to achieve much smaller NPs, S ‾ ⩽ 10  nm, that evidence weak quantum confinement effects on both the absorption edge and th…

Quasifreeπ+production studied using theC12(γ, π+n)B11reaction in theΔ(1232)resonance region

Results are presented from a coincidence study of the {sup 12}C({gamma},{pi}{sup +}{ital n}){sup 11}B quasifree pion production reaction made in the {Delta}-resonance region using tagged photons. Cross sections for reactions originating on 1{ital p}-shell protons are found to be significantly larger than predicted by calculations based on quasifree pion production. It is suggested that more sophisticated calculations, perhaps including medium effects, may be required to reproduce the data. {copyright} {ital 1996 The American Physical Society.}

Investigation of multiparticle final states in12C photoreactions

The ${}^{12}\mathrm{C}(\ensuremath{\gamma},pn)$, ${}^{12}\mathrm{C}(\ensuremath{\gamma},pp)$, ${}^{12}\mathrm{C}(\ensuremath{\gamma},ppp)$, ${}^{12}\mathrm{C}(\ensuremath{\gamma},pp{\ensuremath{\pi}}^{\ifmmode\pm\else\textpm\fi{}})$, ${}^{12}\mathrm{C}(\ensuremath{\gamma},p{\ensuremath{\pi}}^{\ifmmode\pm\else\textpm\fi{}})$ reactions have been studied using tagged photons of energy ${E}_{\ensuremath{\gamma}}=250$--600 MeV. A model which includes all major absorption mechanisms and final state interactions gives results that agree well with the shapes of missing energy spectra, but for some channels the predicted cross sections are too large.

The angular distribution of the 12C(γ,pn) reaction for Eγ=120−150 MeV

The angular distribution of nucleons emitted in the 12C(γ,pn) reaction has been measured using tagged photons at the Mainz microtron MAMI. The variation of the reaction strength with the polar angles of the two emitted nucleons is reported for Eγ=120−150 MeV. The proton angular distribution peaks at more backward angles than the 2H(γ,p) differential cross section indicating a departure from the simple quasi-deuteron model of 2N photo-emission. The distribution shape is in reasonable agreement with microscopic theoretical models which include both π- and ρ-exchange.

Über hydrazide von Polyacrylsäuren. I. Mitt. Darstellung und Eigenschaften der Polyacrylsäurehydrazide

SARS-CoV-2 vaccination modelling for safe surgery to save lives: data from an international prospective cohort study

Abstract Background Preoperative SARS-CoV-2 vaccination could support safer elective surgery. Vaccine numbers are limited so this study aimed to inform their prioritization by modelling. Methods The primary outcome was the number needed to vaccinate (NNV) to prevent one COVID-19-related death in 1 year. NNVs were based on postoperative SARS-CoV-2 rates and mortality in an international cohort study (surgical patients), and community SARS-CoV-2 incidence and case fatality data (general population). NNV estimates were stratified by age (18–49, 50–69, 70 or more years) and type of surgery. Best- and worst-case scenarios were used to describe uncertainty. Results NNVs were more favourable in su…

Mechanisms in theC12(γ,pn)and(γ,pp)Reactions

${}^{12}\mathrm{C}(\ensuremath{\gamma},pn)$ and $(\ensuremath{\gamma},pp)$ cross sections have been measured in kinematics which emphasize direct $2N$ knockout for ${E}_{\ensuremath{\gamma}}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}120--400\mathrm{MeV}$ and ${\ensuremath{\theta}}_{p}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}23\ifmmode^\circ\else\textdegree\fi{}--152\ifmmode^\circ\else\textdegree\fi{}$. The cross sections for both reactions peak strongly in the $\ensuremath{\Delta}$-resonance region. Theoretical calculations that account for the medium dependence of the $\ensuremath{\Delta}$ propagator predict a similar photon energy dependence to the data and describe the …

Proceedings of the 23rd Paediatric Rheumatology European Society Congress: part one

The ALICE experiment at the CERN LHC

Journal of Instrumentation 3(08), S08002 (2008). doi:10.1088/1748-0221/3/08/S08002

Proton photoproduction from 12C

Abstract The 12 C(γ,p) differential cross-section in the Δ-resonance region has been measured using tagged photons. Data are presented for 20 MeV wide photon energy bins at 200, 300, 400 and 500 MeV and for proton angles from 52° to 128°. The present 12 C(γ,p) measurements are compared with previous experiments carried out at Frascati, Tokyo and Bonn. Comparisons are also made with theoretical calculations developed at Gent and Valencia which provide an interpretation of the photon reaction mechanism in terms of the major contributing processes. Coincidence data with correlated neutrons, protons and pions are also presented.

The12C(γ,NN)reaction studied over a wide kinematic range

The ${}^{12}\mathrm{C}(\ensuremath{\gamma},np)$ and ${}^{12}\mathrm{C}(\ensuremath{\gamma},pp)$ reactions have been studied using the Glasgow photon tagging spectrometer at the Mainz MAMI electron microtron for ${E}_{\ensuremath{\gamma}}=150--700$ MeV over a kinematic range which extends well beyond the approximately back-to-back detector arrangements of previous work. For ${}^{12}\mathrm{C}(\ensuremath{\gamma},np)$ the general trends of the missing energy distributions are reproduced over a wide range of kinematics and photon energies by the theory developed by the Valencia group. The corresponding ${}^{12}\mathrm{C}(\ensuremath{\gamma},pp)$ channel is overestimated by a factor of \ensurem…

Characterization of prejunctional muscarinic autoreceptors in the guinea-pig trachea

1. The effects of ten muscarinic antagonists on electrically evoked [3H]-acetylcholine release and muscle contraction were compared in an epithelium-free preparation of the guinea-pig trachea that had been preincubated with [3H]-choline. 2. The M3-selective antagonists UH-AH 37, 4-diphenyl-acetoxy-N-piperidine methobromide and para-fluorohexahydrosiladiphenidol were more potent in reducing the contractile response than in facilitating the evoked [3H]-acetylcholine release. Hexahydrosiladiphenidol did not discriminate between pre- and postjunctional effects. The rank order of the postjunctional potencies of the ten antagonists as well as the postjunctional pA2 values obtained for hexahydrosi…

12C(γ,π+n) and 12C(γ,π+p) reactions across the Δ resonance region

Abstract Differential cross-sections from (γ,π+n) and (γ,π+p) experiments on 12C are presented together with a microscopic model calculation. The comparison of experimental data with theory confirms that quasifree pion production is the dominant process for the (γ,π+n) reaction. The comparison of (γ,π+p) with (γ,π+n) data shows the importance of final state interactions. first time to experimentally study the strength and the possible mechanisms involved in the final state interaction.

Nuclear pion photoproduction in theΔresonance region

A measurement of the /sup 12/C( gamma , pi /sup +/n)/sup 11/B reaction in quasifree pi -production kinematic regimes has been performed using tagged photons in conjunction with large solid angle pi and n detectors. The aim of the experiment was to investigate predicted modifications to the Delta excitation of nucleons and their subsequent propagation and decay, brought about by the nuclear medium. Differential cross sections are presented for photon energies spanning the Delta (1232) excitation region. The measurements are consistent with distorted wave impulse approximation calculations in which the amplitude for proton Delta excitation, followed by Delta propagation and decay to pi /sup +…

Über Hydrazide von Polyacrylsäuren. II. Mitt. Darstellung und Eigenschaften von Polyacrylsäurehydrazonen

Ion storage technique for very long living states: The decay rate of the 5D 3/2 state of Ba II

The metastable 5D 3/2 state of Ba+ is used to demonstrate the possibility of the ion storage technique for the measurement of extremely long lived states. The ions are confined in a r.f. quadrupole trap and excited by a strong pulsed tunable dye laser to the 6P 1/2 state which partially decays into the 5D 3/2 state. Sampling of the time development of the ground state population leads to the determination of the 5D 3/2 decay rate. Using He as a buffer gas at a pressure of about 10−6 mbar to initially store the ions, varying the gas density and extrapolating to zero pressure, we find for the lifetime $$\tau _{D_{3/2} } = 17.5 \pm 4s$$ .

The ALMA REBELS Survey: The First Infrared Luminosity Function Measurement at $\mathbf{z \sim 7}

We present the first observational infrared luminosity function (IRLF) measurement in the Epoch of Reionization (EoR) based on a UV-selected galaxy sample with ALMA spectroscopic observations. Our analysis is based on the ALMA large program Reionization Era Bright Emission Line Survey (REBELS), which targets 42 galaxies at $\mathrm{z=6.4-7.7}$ with [CII] 158$\micron$ line scans. 16 sources exhibit a dust detection, 15 of which are also spectroscopically confirmed through the [CII] line. The IR luminosities of the sample range from $\log L_{IR}/L_\odot=11.4$ to 12.2. Using the UVLF as a proxy to derive the effective volume for each of our target sources, we derive IRLF estimates, both for de…

Studien zum vorgang der wasserstoffübertragung 32 über einige faktoren, welche das carbinol-pinakol-verhältnis und die asymmetrische induktion bei der elektrochemischen reduktion von acetophenon bestimmen

Bei der elektrochemischen Reduktion von Acetophenon zum Pinakol wird der Einflus zugesetzter chiraler Leitsalze wie (I) oder (II) auf den Reaktionsablauf untersucht.

Etude de l'arôme de vieillissement de vins doux naturels de grenache noir du Roussillon

*INRA Unité de Recherches Biopolymères Arômes Montpellier (FRA) Diffusion du document : INRA Unité de Recherches Biopolymères Arômes Montpellier (FRA); National audience