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We describe first measurement in a novel thin-layer channel flow cell designed for the investigation of heterogeneous electrocatalysis on porous catalysts. For the interpretation of the measurements, a macroscopic model for coupled species transport and reaction, which can be solved numerically, is feasible. In this paper, we focus on the limiting current. We compare numerical solutions of a macroscopic model to a generalization of a Leveque-type asymptotic estimate for circular electrodes, and to measurements obtained in the aforementioned flow cell. We establish that on properly aligned meshes, the numerical method reproduces the asymptotic estimate. Furthermore, we demonstrate that the measurements are partially performed in the sub-asymptotic regime, in which the boundary layer thickness exceeds the cell height. Using the inlet concentration and the diffusion coefficient from literature, we overestimate the limiting current. On the other hand, the use of fitted parameters leads to perfect agreement between model and experiment.

Absolute VUV optical absorption cross sections for ozone have been measured between 325 and 110 nm (3.0 - 11.3 eV) using a synchrotron radiation source. Vibrational fine structure is resolved in Rydberg bands and comparison of this with the limiting bands in the photoelectron spectrum confirms that the order (increasing ionization energy) of the three lowest ionization bands is . Near-threshold electron energy-loss spectra have also been recorded. In these, in addition to the known triplet states between 1 and 2 eV, a low-lying triplet state has been located around 3.4 eV and several others between 6 and 9 eV. Characterization of the valence states (both optically allowed and forbidden) are discussed in relation to the results of early theoretical computations which seem to give a good account of the ozone spectrum.

Abstract-This paper traces the development/evolution of three of our recently proposed MPEG coded video traffic models, that can capture the statistical properties of MPEG video data. The basic ideas behind these models are to decompose an MPEG compressed video sequence into several parts according to motion/scene complexity or data structure. Each part is described by a self-similar process. These different self-similar processes are then combined to form the respective models. In addition, Beta distribution is used to characterize the marginal cumulative distribution (CDF) of the self-similar processes. Comparison among the three models shows that the latest model (called the simple IPB composite model) is the most practical one in terms of accuracy and complexity. Simulations based on many real MPEG compressed movie sequences, including StarWars, have demonstrated that the simple model can capture the autocorrelation function (ACF) and the marginal CDF very closely.

The DArk Matter Particle Explorer (DAMPE) is a space-borne particle detector designed to probe electrons and gamma-rays in the few GeV to 10 TeV energy range, as well as cosmic-ray proton and nuclei components between 10 GeV and 100 TeV. The silicon-tungsten tracker-converter is a crucial component of DAMPE. It allows the direction of incoming photons converting into electron-positron pairs to be estimated, and the trajectory and charge (Z) of cosmic-ray particles to be identified. It consists of 768 silicon micro-strip sensors assembled in 6 double layers with a total active area of 6.6 m 2 . Silicon planes are interleaved with three layers of tungsten plates, resulting in about one radiation length of material in the tracker. Internal alignment parameters of the tracker have been determined on orbit, with non-showering protons and helium nuclei. We describe the alignment procedure and present the position resolution and alignment stability measurements. NUDBGO STK PSD z x y Figure 1: Schematic view of the DAMPE detector. Sensitive detectors and support structures are shown. The z-axis of the DAMPE coordinate system is oriented to the zenith, orthogonal to the STK planes and y points to the Sun.10 GeV to 100 TeV, with excellent energy resolution and direction precision [1,2]. The main objectives of DAMPE are the identification of possible indirect signatures of Dark Matter annihilation or decay, improving the understanding of the origin and propagation mechanisms of high energy cosmic rays and gamma-ray astronomy. It consists of four sub-detectors ( Figure 1) stacked together as follows, moving from top to bottom. First is a Plastic Scintillator-strip Detector (PSD), which measures the cosmic ray charge (Z) and provides the veto signal for charged particles in gamma-ray detection. It is followed by a Silicon-Tungsten tracKer-converter (STK), that is described in detail in the next section. Next, there is an imaging calorimeter made of 14 layers of Bismuth Germanium Oxide (BGO) bars in a hodoscopic arrangement with a total thickness of about 32 radiation lengths, which provides a precise energy measurement and particle identification for electron/hadron separation. The BGO is aided by the NeUtron Detector (NUD), a borondoped plastic scintillator detecting delayed neutrons coming from hadronic interactions at high energies, which serves to improve the electron/hadron separation power.The STK is a key component of DAMPE, allowing the trajectory and absolute ion charge (Z) of incoming particles to be reconstructed and measured respectively. Moreover, thanks to its high position resolution, the direction of incoming photons converting into electron-positron pairs in the STK's tungsten plates can be precisely reconstructed. In order to fully exploit the trajectory reconstruction capabilities of the STK, a precise alignment of the instrument is needed, as explained in this paper.The paper is organized as follows. In Section 2 the STK is briefly described. Section 3 provides the details of the on-orbit data and simulati...