Iterative Algorithms for Multiscale State Estimation, Part 1: Concepts

The objective of the present investigation is to explore the potential of multiscale refinement schemes for the numerical solution of dynamic optimization problems arising in connection with chemical process systems monitoring. State estimation is accomplished by the solution of an appropriately posed least-squares problem. To offer at any instant of time an approximate solution, a hierarchy of successively refined problems is designed using a wavelet-based Galerkin discretization. In order to fully exploit at any stage the approximate solution obtained also for an efficient treatment of the arising linear algebra tasks, we employ iterative solvers. In particular, we will apply a nested iteration scheme to the hierarchy of arising equation systems and adapt the Uzawa algorithm to the present context. Moreover, we show that, using wavelets for the formulation of the problem hierarchy, the largest eigenvalues of the resulting linear systems can be controlled effectively with scaled diagonal preconditioning. Finally, we deduce appropriate stopping criteria and illustrate the characteristics of the solver with a numerical example.     

AFM in Organic Solid State Reactions

Abstract

Organic solid-state reactions are probed with the atomic force microscope (AFM). In all cases phase rebuilding gives rise to characteristic submicroscopic features which change in shape due to phase transformation in later stages of the chemical reaction. Photo-(E/Z)-isomerization of olefin 1 occurs in the crystal, photodimerization of 9-chloroanthracene 3 is used as a probe for characterizing the luminosity distribution of SNOM-tips. Gas/solid imbibition in chiral host 5 proceeds enantiospecifically. Histidine crystals form the dihydrochloride with HC1, ammonia and methylamine react face-selectively with crystalline adipic acid 8, furane-2-carboxylic acid 10 and 2-mercaptobenzothiazole 12. Crystals of olefin 14 add chlorine. Solid-state diazotations and subsequent transformations of the solid diazonium nitrates into triazenes occur quantitatively. Solid/solid pinacol- and benzilic acid rearrangements are probed with the AFM. The features formed by long range molecular movements relate to the crystal packing and are thus different on different faces. Correlations with X-ray structural data are demonstrated. All reactions proceed to completion on a preparative scale and do not produce wastes as do their less selective counterparts if performed in solution.     

Dynamical multistability induced by radiation pressure in high-finesse micromechanical optical cavities

We analyze the nonlinear dynamics of a high-finesse optical cavity in which one mirror is mounted on a flexible mechanical element. We find that this system is governed by an array of dynamical attractors, which arise from phase locking between the mechanical oscillations of the mirror and the ringing of the light intensity in the cavity. We develop an analytical theory to map out the diagram of attractors in parameter space, derive the slow amplitude dynamics of the system, including thermal fluctuations, and suggest a scheme for exploiting the dynamical multistability in the measurement of small displacements.     

Device calibration impacts security of quantum key distribution

Characterizing the physical channel and calibrating the cryptosystem hardware are prerequisites for establishing a quantum channel for quantum key distribution (QKD). Moreover, an inappropriately implemented calibration routine can open a fatal security loophole. We propose and experimentally demonstrate a method to induce a large temporal detector efficiency mismatch in a commercial QKD system by deceiving a channel length calibration routine. We then devise an optimal and realistic strategy using faked states to break the security of the cryptosystem. A fix for this loophole is also suggested.     

Zur Nachweisung von Alkaloiden in Leichentheilen

Ohne Zusammenfassung     

Untersuchung der Flammenemission von Metallhalogeniden und deren Nutzung zur Analytik der Halogene

Departing from the until now well known A and B systems of the indium and gallium halide emissions the authors tried to find further spectra of molecule bands in flames. The following band systems were observed: InF¹ (A, B and C systems), GaF¹ (A, B and C systems), A1F¹ (A system), T1C1¹, TlBr¹, TII¹ and the C systems of the GaCl, GaBr, InCl and InBr molecules.From the behaviour of the intensities of excited and nonexcited MeX species and the existence of InF-C bands (excitation energy 5.30 eV) in the hydrogen-nitrogen diffusion flame it could be derived that the excited state results from the reaction of metal and halogen atoms. Furthermore the experimental results of MeX intensity measurements indicate reactions of excited molecules with particles of flame gases. This is especially valid for the A and B systems of the indium and gallium halides (triplet states) which have as a result of the forbidden transitions a relatively long life time. Using other gas mixtures (Hr-air, propane-air) and observation of CuX and alkaline earth halide bands as well gave the possibility to set up a block diagram of optimum conditions for measuring the different MeX emissions.Examination of the analytical performance gave detection limits of 0.7 $\text{mg}\text{l}$ for F^?1 and about 4 $\text{mg}\text{l}$ for Cl^?, Br^? and I^? by means of InX emissions. The limits of the concentration ratios for the determination of traces were 1:640 (Cl^? in HBr) up to 1:60,000 (I^? in HF). The best determinations of other halogens are possible in HC1 and HF matrices.     

Herstellung von Aryl-isothiocyanaten aus Arylaminen und Bis-diäthylthiocarbamoylsulfiden

The preparation of aryl-isothiocyanates from aryl-amines and bis-diethylthiocarbamoyl sulfides is reported and mechanisms are proposed for these reactions of thiocarbamoyl derivatives.