Tracking model of an adaptive lattice filter for a linear chirp FMsignal in noise

The paper studies the behavior of the partial correlation (PARCOR) coefficients and the output misadjustment of the stochastic gradient adaptive lattice filter in response to a complex linear chirp FM signal in white Gaussian noise. Analytic expressions for the optimal PARCOR coefficients of the filter are derived. Analytic as well as iterative models for a three-stage filter are also derived. The analytic expressions show that the tracking and convergence properties of the filter are separate phenomena. Simulation results also show that the spectral contents of the PARCOR coefficients for the stochastic gradient update algorithm consist of a stationary and a linearly swept component. A single-stage model is developed to explain this behavior. Finally, output misadjustment plots for the filter show that an optimum value for the forgetting factor can be obtained to minimize the misadjustment, but the value required to achieve local minimum misadjustment varies with each stage of the filter. It is shown that in applications where the input has a high signal-to-noise ratio (SNR), the misadjustment decreases rapidly at each successive stage, thus implying that relatively short filter lengths are sufficient to provide effective tracking     

Aluminum Oxide at the Monolayer Limit via Oxidant-Free Plasma-Assisted Atomic Layer Deposition on GaN

Atomic layer deposition (ALD) is an essential tool in semiconductor device fabrication that allows the growth of ultrathin and conformal films to precisely form heterostructures and tune interface properties. The self-limiting nature of the chemical reactions during ALD provides excellent control over the layer thickness. However, in contrast to idealized growth models, it is challenging to create continuous monolayers by ALD because surface inhomogeneities and precursor steric interactions result in island growth. Thus, the ability to create closed monolayers by ALD would offer new opportunities for controlling interfacial charge and mass transport in semiconductor devices, as well as for tailoring surface chemistry. Here, encapsulation of c-plane gallium nitride (GaN) with ultimately thin (≈3 Å) aluminum oxide (AlO_x) is reported, which is enabled by the partial conversion of the GaN surface oxide into AlO_x using sequential exposure to trimethylaluminum (TMA) and hydrogen plasma. Introduction of monolayer AlO_x decreases the work function and enhances reactivity with phosphonic acids under standard conditions, which results in self-assembled monolayers with densities approaching the theoretical limit. Given the high reactivity of TMA with surface oxides, the presented approach likely can be extended to other dielectrics and III–V-based semiconductors, with relevance for applications in optoelectronics, chemical sensing, and (photo)electrocatalysis.     

Fully Automated Production and Characterization of 64Cu and Proof‐of‐Principle Small‐Animal PET Imaging Using 64Cu‐Labelled CA XII Targeting 6A10 Fab

⁶⁴Cu is a cyclotron‐produced radionuclide which offers, thanks to its characteristic decay scheme, the possibility of combining positron emission tomography (PET) investigations with radiotherapy. We evaluated the Alceo system from Comecer SpA to automatically produce ⁶⁴Cu for radiolabelling purposes. We established a ⁶⁴Cu production routine with high yields and radionuclide purity in combination with excellent operator radiation protection. The carbonic anhydrase XII targeting 6A10 antibody Fab fragment was successfully radiolabelled with the produced ⁶⁴Cu, and proof‐of‐principle small‐animal PET experiments on mice bearing glioma xenografts were performed. We obtained a high tumor‐to‐contralateral muscle ratio, which encourages further in vivo investigations of the radioconjugate regarding a possible application in diagnostic tumor imaging.     

Interference Analysis of Filtered Multitone Modulation Over Time-Varying Frequency- Selective Fading Channels

We consider in this paper filtered multitone (FMT) modulation over frequency-selective time-varying fading channels. Due to the phase and amplitude distortion introduced by the fading channel, not only is the orthogonality among different subcarriers destroyed, but also the perfect Nyquist sampling condition of the baseband matched filters is no longer valid. Consequently, interchannel, as well as intersymbol, interference will cause distortions to the transmitted signals. In this paper, the interference caused by the channel frequency selectivity and time variance is quantified by analyzing the demodulated signals at the receiver under several different fading-channel conditions. An analysis of the average carrier-to-interference (C/I) ratio of the FMT system is provided in order to demonstrate the underlying tradeoff between spectral efficiency and system performance. For comparison purposes with other multicarrier communication systems (or modulation techniques), the C/I ratio of the conventional orthogonal frequency-division multiplexing system is also provided and compared with that of the FMT system under the same channel conditions and spectral efficiency. Finally, numerical and simulation results are given that confirm the C/I ratio results obtained     

The pipeline bus: An interconnection network for multiprocessor systems

The design of a network switch for synchronously clocked packet switching networks is presented. The switch includes the node interface and logic handling of the arbitration and routing for a large class of network topologies, namely n-dimensional rectangular grids including hypercubes and other highly efficient topologies. In the context of the SUPRENUM project the paper concentrates on two-dimensional meshes. Routing, arbitration, blocking, and fault tolerance issues are discussed.     

Synthese von Aldehyden und Carbonsäuren durch katalytische Oxidation vicinaler Diole

Synthesis of Aldehydes and Carboxylic Acids by Catalytic Oxidation of Vicinal Diols Results of studies on oxidative cleavage of aliphatic vicinal diols by oxygen in the presence of cobaltous compounds are reported. The effect of experimental conditions on the yield of aldehydes and acids are presented. Yields of 90% resp. 86% of these compounds are obtained.