Stereoselective Access to Fully Substituted Aldehyde‐Derived Silyl Enol Ethers by Iridium‐Catalyzed Alkene Isomerization

An in situ generated cationic Ir‐catalyst isomerizes simple allylic silyl ethers into valuable, fully substituted aldehyde‐derived silyl enol ethers. Importantly, by judicious choice of substrate, either of the two possible stereoisomers of a given enolate derivative is accessible with complete stereoselectivity. One‐pot isomerization‐aldol and isomerization‐allylation processes illustrate the synthetic utility of this method.     

Preparation of Enantiomerically Pure Compounds Employing Anodic Oxidations of Carboxylic Acids – A Late Review of Research Done in the 1980ies

There are widely unknown enantiopure building blocks and non‐conventional transformations described in this old work that could become useful in today's diversity‐oriented organic synthesis world. Coupling and mixed couplings of functionalized CF₃‐substituted chiral radicals by Kolbe electrolysis of carboxylic acids lead to hexafluoro‐hexane‐2,5‐diol and to butyro‐ and valerolactone derivatives with functional‐group relationships that normally require components with reactivity umpolung. Oxidative decarboxylation of amino‐acid and peptide derivatives by Hofer‐Moest electrolyses provide entry into the synthetic use of chiral acyliminium‐ion intermediates. Chiral oxazoline and thioazoline building blocks (from serine, threonine, and cysteine) are accessible for substitutions and cycloadditions. The stereochemical course of oxidative CO₂H replacement in serine by nucleophilically introduced groups with retention of configuration is discussed.     

Thermoluminescence and electron paramagnetic resonance (EPR) studies of mineral chrysocolla (dioptase)

The natural mineral chrysocolla (CuSiO₃·2H₂O) has been investigated in terms of thermally stimulated luminescence and EPR measurements. The glow curves for natural samples present three glow peaks at 190, 357 and 450°C. Pre annealed and subsequently irradiated samples give rise to four glow peaks at 140°C, 193°C, 305°C and 450°C. The formation of H^o centers at the expense of water molecules present in the channels has been identified by EPR measurements.     

Photostimulated luminescence properties of BaFBr:Eu under ion irradiation

The photostimulated luminescence (PSL) properties of the phosphor BaFBr:Eu after ion beam irradiation was analyzed; in particular, the PSL intensity dependent on ion fluence. The PSL intensity increased linearly with the ion fluence up to 10¹² ions/cm², and subsequently decreased gradually. The ion fluence dependence was observed to be similar among samples containing different F centers or different Eu concentrations. The fluence dependence was quantitatively analyzed based on a trapping model, in which competition between the trapping processes to storage centers and radiation defects is assumed; the model explained the experimental data quantitatively. The results indicate that radiation defects influence the PSL properties via the trapping of photostimulated electrons.     

A stochastic programming model for scheduling call centers with global Service Level Agreements

We consider the issue of call center scheduling in an environment where arrivals rates are highly variable, aggregate volumes are uncertain, and the call center is subject to a global service level constraint. This paper is motivated by work with a provider of outsourced technical support services where call volumes exhibit significant variability and uncertainty. The outsourcing contract specifies a Service Level Agreement that must be satisfied over an extended period of a week or month. We formulate the problem as a mixed-integer stochastic program. Our model has two distinctive features. Firstly, we combine the server sizing and staff scheduling steps into a single optimization program. Secondly, we explicitly recognize the uncertainty in period-by-period arrival rates. We show that the stochastic formulation, in general, calculates a higher cost optimal schedule than a model which ignores variability, but that the expected cost of this schedule is lower. We conduct extensive experimentation to compare the solutions of the stochastic program with the deterministic programs, based on mean valued arrivals. We find that, in general, the stochastic model provides a significant reduction in the expected cost of operation. The stochastic model also allows the manager to make informed risk management decisions by evaluating the probability that the Service Level Agreement will be achieved.     

A new methodology for sensitivity and stability analysis of analytic network models

In this paper we develop a methodology to study the sensitivity and the stability of models built using the Analytic Network Process. We study two types of stability: core and solution stability. The former deals with finding the region of the perturbation space in which the initial solution (i.e., the alternative that is ranked first) obtained from the ANP model remains most preferred. The latter deals with finding the regions of the perturbation space in which the solutions that were not initially most preferred (i.e., alternatives that were not ranked first) become most preferred (i.e., they are ranked first). The methodology consists of three stages: generation of the perturbation space, finding the boundaries of the regions in the perturbation space in which the different alternatives are ranked first, and finding the stability regions.     

Controlled coupling of NV defect centers to plasmonic and photonic nanostructures

Nitrogen-vacancy (NV) defect centers in diamond have recently emerged as promising candidates for a number of applications in the fields of quantum optics and quantum information, such as single photon generation and spin qubit operations. The performance of these defect centers can strongly be enhanced through coupling to plasmonic and photonic nanostructures, such as metal particles and optical microcavities. Here, we demonstrate the controlled assembly of such hybrid structures via manipulation with scanning near-field probes. In particular, we investigate the plasmonic enhancement of the single photon emission through coupling to gold nanospheres as well as the coupling of diamond nanocrystals to the optical modes of microsphere resonators and photonic crystal cavities. These systems represent prototypes of fundamental nanophotonic/plasmonic elements and provide control on the generation and coherent transfer of photons on the level of a single quantum emitter.     

Small Ball Probabilities Around Random Centers of Gaussian Measures and Applications to Quantization

Let be a centered Gaussian measure on a separable Hilbert space (E, ). We are concerned with the logarithmic small ball probabilities around a -distributed center X. It turns out that the asymptotic behavior of –log (B(X,)) is a.s. equivalent to that of a deterministic function _R (). These new insights will be used to derive the precise asymptotics of a random quantization problem which was introduced in a former article by Dereich, Fehringer, Matoussi, and Scheutzow.⁽⁸⁾     

高阶导数的插值公式

本文我们得到一种插值公式,它通过一系列点,且满足该点列上的初始高阶导数值.最后还给出这种插值公式的误差估计.