81 research outputs found
Disentanglement of overlapping spectrograms in attosecond time-resolved photoelectron spectroscopy of solids
No full textGebauer A, Schabbehard T, Maschmann L, Pfeiffer W. Disentanglement of overlapping spectrograms in attosecond time-resolved photoelectron spectroscopy of solids. Physical Review B . 2025;111(12): 125146.Attosecond time-resolved photoelectron spectroscopy reveals photoemission dynamics, for example, via reconstruction of attosecond beating by interference of two-photon transitions (RABBITT). However, the multitude of photoemission peaks in a RABBITT spectrogram often limits the applicability of the method to well-separated photoemission channels. Here, we derive relations between RABBITT oscillations of sidebands and principal bands within strong field approximation. This allows extracting timing information on the photoemission dynamics for rather convoluted RABBITT spectra, for which the common analysis would fail. This improvement is demonstrated for simulated overlapping RABBITT spectrograms based on a solid-state photoemission model showing the robust reconstruction of the individual photoemission delays
Inclusive J/Psi production in decays of B mesons
No full textThe production of J/Psi in B meson decays has been measured on the Y(4S) resonance using the Crystal Ball detector at the e+e- storage ring DORIS II. The J/Psi is identified by its e+e- decay mode. We obtain a branching ratio of BR(B->J/Psi X)=(1.12+-0.33+-0.25)% in good agreement with theoretical predictions based on color suppression. The J/Psi momentum distribution is observed to be peaked at high values. This implies a substantial contribution from direct B meson decays to the J/Psi. In addition upper limits on J/Psi production in Y(1S) and Y(2S) decays and in continuum processes are determined
Inklusive Charmoniumproduktion in Zerfaellen der UPSILON-Resonanzen
No full textSIGLETIB Hannover: MA 4659 / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman
Mechanical characterization of a Au coated carbon nanotube multi-layered structure
No full textMultiwalled Carbon Nanotube (MWCNT) -coated surfaces have been proved to be able to provide stable resistance for the electrical contact under low force conditions since they can offer a compliant support for the conducting gold layer. However, the contact mechanics of the Au/MWCNTs composite have not been understood. In this study, a finite element multi-layered contact model was developed, in which the top layer was modeled as a composite and under layer was modeled as CNT forest. The study shows that this complex surface is best modeled as a multi-layered structure. The model is optimized and validated with nano-indenter data. The model can help to better understand the structure and material properties of Au/CNTs surfaces, and can provide guidance to optimize the surface in terms of contact resistance performance in MEMS switches
Determination of Gamma-ee of the Upsilon(1S) and Upsilon(2S) Resonances, and Measurement of R At W = 9.39 GeV.
No full textUsing the Crystal Ball detector operating at the DORIS II storage ring we have measured the leptonic partial widths Fee of the Y(1S) and Y(2S) resonances. We find Gamma-ee(Y(1S)) = 1.34+-0.03+-0.06 keV andGamma-ee(Y(2S)) = 0.56+-0.04+-0.02 keV.The effect on Gamma-ee of applying different prescriptions for radiative corrections is discussed. W e also measure R, the ratio of non-resonant hadronic cross section to the Born cross section of mu pair production, at c.m. energy W = 9 . 3 9 G e V to beR=3.48+-0.04+-0.16
Caracterização do ambiente marinho do Estado do Espírito Santo utilizando dados do banco Nacional de Dados Oceanográficos
No full textabstractO Banco Nacional de Dados Oceanográficos (BNDO), vinculado à Diretoria de Hidrografia e Navegação (DHN) da Marinha do Brasil consiste num acervo de dados que podem ser disponibilizados ao público gratuitamente e com mínima burocracia. Entretanto, pouco se sabe da validade destes dados para a caracterização de extensas áreas marinhas. Neste sentido, foi escolhida a região marinha do Estado do Espírito Santo compreendida entre os paralelos 18°S e 20°S e meridianos 41°W e 37°W, para verificar tal hipótes
Ein analoges 40 MHz Bandpaßfilter für niedrige Versorgungsspannungen
No full textS.113-118Der Beitrag beschreibt ein integriertes analoges Bandpaßfilter, realisiert in einer 1 Mikrometer BiCMOS-Technologie. Die Implementierung der Schaltung basiert auf einer Differenzpfad-Gyrator-Technik zur Emulation der Induktivitäten. Die Struktur des Filters besteht aus einer Reihenschaltung von elliptischem Hoch- und Tiefpaß. Aufgrund der hohen Bandbreite von 8 MHz sowie einer entsprechend hohen Bandmittenfrequenz von 40 MHz stellt die vorgestellte Realisierung die kostengünstigste Alternative dar. Bei einer Versorgungsspannung von 4 V beträgt der Stromverbrauch 170 mA. Zur Realisierung von Frequenz und Gütetuning wurden harmonische Oszillatoren mit den im Filter verwendeten Basisblöcken integriert. Die gesamte Chipfläche der Schaltung beträgt 9 mm2
XFEL Cryomodule Transport: from the Assembly Laboratory in CEA-Saclay (France) to the Test-Hall in DESY-HAMBURG (GERMANY)
No full textThe one hundred, 12 m long XFEL 1.3 GHz cryomodules are assembled at CEA Saclay (F) and have therefore to be transported, fully assembled, to the installation site in DESY Hamburg (D). Various studies and tests have been performed to assess and minimize the risk of damages during transport; a new transport frame and a specialised company are being used for the series transport. This paper resumes the studies performed, describes the final configuration adopted for the series transport and the results obtained for the first XFEL modules
A low-voltage BiCMOS power stage
No full textS.155-159A novel low-voltage class AB output stage integrated in BiCMOS technology is presented. It features a novel class AB low impedance output stage and has a simple but efficient quiescient current regulation. The amplifier exhibits a 3dB bandwidth of 5MHz while driving a combined parallel load of 30_/300pF at 2V power supply voltage. The voltage amplification of the output stage is greater than 1.0 which simplifies the design of the preceeding stage
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