114 research outputs found
Dynamic memory recovery in PASCAL
No full textBei Benutzung der Datenstruktur Pointer in PASCAL tritt selbst bei kleineren Programmen schnell Speicherüberlauf ein, wenn nicht entsprechende Vorkehrungen getroffen werden. Aber gerade die Möglichkeit dynamischer Variablen ist ein entscheidendes Merkmal von PASCAL, so daß es der Verfasser für dringend angeraten hält, Möglichkeiten zur weiteren Verwendung nicht mehr benötigten Speicherplatzes zu schaffen. In der vorliegenden Arbeit werden zunächst Methoden beschrieben, wie diese Rückführung vom Benutzer bewerkstelligt werden kann. Gleichwohl ist es für eine moderne Programmiersprache unzumutbar, daß zum einen etwas derart Fundamentales vom Benutzer implementiert werden soll und zum andern dies ja für jedes Programm und Unterprogramm von neuem geschehen muß. In einem zweiten Teil der Arbeit werden daher Methoden beschrieben, wie die dynamische Speicherplatzverwaltung durch den Compiler geschehen kann. Im Gegensatz zu bekannten Methoden wird ein Kompromiß zwischen möglichst optimaler Rückführung und schneller Rechenzeit gesucht. Der Verfasser hofft dazu beizutragen, daß die unbedingte Notwendigkeit der Speicherplatzrückführung erkannt und in den Report aufgenommen wird und, daß bald mehr Compiler mit dieser Fähigkeit auf den Markt kommen.When using the data structure pointer even for small programs the memory is filled up quickly if no precautions were made. However, especially the possibility of dynamic variables is a fundamental feature of PASCAL, so that in the authors opinion it is of great importance to manage the further use of not-more-needed memory. In the present paper first methods are described how this can be done by the programmer. However, for a modern programming language it is a tall order to leave this important task to the user and, moreover, this has to be done for every program and subprogram separately. Therefore, in a second chapter methods will be described, how the compiler can manage the dynamic memory recovery in PASCAL. In contrast to known methods here it has been looked for a compromise between optimal recovery and time efficiency. The author hopes, that the fundamental necessity of recovering memory not longer needed will be recognized and entered in the report and, that more compilers with this ability will come into the market
Using Fiber Bragg Grating Sensors to Quantify Temperature Non-Uniformities in Plasmonic Catalyst Beds under Illumination
No full textDistinguishing between photothermal and non-thermal contributions is essential in plasmon catalysis. Use of a tailored optical temperature sensor based on fiber Bragg gratings enabled us to obtain an accurate temperature map of an illuminated plasmonic catalyst bed with high spatiotemporal resolution. Its importance for quantification of the photothermal and non-thermal contributions to plasmon catalysis is demonstrated using a Ru/Al2O3 catalyst. Upon illumination with LEDs, we measured temperature differences exceeding 50 °C in the top 0.5 mm of the catalyst bed. Furthermore, we discovered differences between the surface temperature and the temperature obtained via conventional thermocouple measurements underneath the catalyst bed exceeding 200 °C at 2.6 W cm−2 light intensity. This demonstrates that accurate multi-point temperature measurements are a prerequisite for a correct interpretation of catalysis results of light-powered chemical reactions obtained with plasmonic catalysts.ImPhys/Optic
Low Temperature Sunlight-Powered Reduction of CO<sub>2</sub> to CO Using a Plasmonic Au/TiO<sub>2</sub> Nanocatalyst
Get PDFSunlight-powered reduction of CO2 to fuels and chemicals is a promising strategy to close the carbon loop and facilitate the energy transition. In this research, we demonstrate that Au nanoparticles supported on TiO2 are an efficient plasmonic catalyst for the sunlight-powered reverse water-gas shift (rWGS) reaction. A maximum CO production rate of 429 mmol ⋅ gAu−1 ⋅ h−1 with a selectivity of 98 % and an apparent quantum efficiency of 4.7 % were achieved using mildly concentrated sunlight (1.44 W ⋅ cm−2 equals 14.4 sun). The CO production rate showed an exponential increase with increasing light intensity, suggesting that the process is mainly promoted by a photothermal effect. Thermal reference experiments with the same catalysts promoted CH4 formation, dropping the CO selectivity to 70 %. Thus, mildly concentrated sunlight can efficiently and selectively enhance the promotion of the rWGS reaction without using external heating.ImPhys/Optic
Measurement of the D+/- production asymmetry in 7 TeV pp collisions
Get PDFThe asymmetry in the production cross-section \sigma of D+/- mesons, A_P = (\sigma(D+) - \sigma(D-))/(\sigma(D+) + \sigma(D-)), is measured in bins of pseudorapidity \eta and transverse momentum p_T within the acceptance of the LHCb detector. The result is obtained with a sample of D+ -> K_S pi+ decays corresponding to an integrated luminosity of 1.0 fb^-1, collected in pp collisions at a centre of mass energy of 7 TeV at the Large Hadron Collider. When integrated over the kinematic range 2.0 K_S pi+ decay is negligible. No significant dependence on \eta or p_T is observed
Measurement of the time-dependent CP asymmetry in B0 -> J/ψ KS0 decays
Get PDFThis Letter reports a measurement of the CP violation observables SJ/ψK0S and CJ/ψK0S in the decay channel B0→J/ψK0S performed with 1.0 fb−1 of pp collisions at s√=7 TeV collected by the LHCb experiment. The fit to the data yields SJ/ψK0S=0.73±0.07(stat)±0.04(syst) and CJ/ψK0S=0.03±0.09(stat)±0.01(syst). Both values are consistent with the current world averages and within
expectations from the Standard Model
First observation of Bs → J/ψf0(980) decays
Get PDFUsing data collected with the LHCb detector in proton–proton collisions at a centre-of-mass energy of 7 TeV, the hadronic decay is observed. This CP eigenstate mode could be used to measure mixing-induced CP violation in the system. Using a fit to the π+π− mass spectrum with interfering resonances gives . In the interval ±90 MeV around 980 MeV, corresponding to approximately two full f0 widths we also find , where in both cases the uncertainties are statistical and systematic, respectively
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