807 research outputs found

    Stereochemistry of Complex Halides of the Transition Metals

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    The aim of this lecture i& to provide a survey of the stereochemistry of the tetrahalogeno complexes of the metal ions of the first transition series. In particular we wish to consider which non-bonding electron configurations favour the formation of regular tetrahedral complexes but we pass from this to examine the shape of four-coordinate complexes with other non-bonding -electron arrangements. Recent experimental studies dealing with the preparation of various metal complexes having d 2, d 5, d 6 and d 8 non-bonding configurations will be summarised and the results of the investigations of the structures of these complexes are discussed

    El Renacimiento de la Química Inorgánica

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    Unified Behavior of Alkali Core-Level Binding-Energy Shifts Induced by sp Metals

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    Thin overlayers of Na, K, Rb, and Cs on different sp-metal substrates have been investigated using photoelectron spectroscopy. The alkali core levels show clearly resolved binding-energy shifts between the surface layer, the intermediate layer(s), and the interface layer. The magnitude of these shifts depends on sp metal and on alkali metal. The layer-resolved core-level binding-energy shifts are well reproduced by models based on a thermodynamical description. For three-layer alkali films the core-level binding energy of the intermediate layer is found to exhibit a small but significant shift between different sp-metal substrates. A simple relationship between the core-level binding-energy shift for the interface layer and the difference in rs value between the sp substrate and the adsorbate is shown to exist

    Soft x-ray photoemission studies of Hf oxidation

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    Charging of oxide films under x rays is an important issue that must be taken into consideration for determination of core-level binding energies as well as valence band offsets. Measurements are taken as a function of time, thickness, and annealing condition. Photoemission results show the presence of metallic Hf with the 4f7/2 binding energy of 18.16 eV, and at least one clear suboxide peak

    Effects of a localized beam on the dynamics of excitable cavity solitons

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    We study the dynamical behavior of dissipative solitons in an optical cavity filled with a Kerr medium when a localized beam is applied on top of the homogeneous pumping. In particular, we report on the excitability regime that cavity solitons exhibits which is emergent property since the system is not locally excitable. The resulting scenario differs in an important way from the case of a purely homogeneous pump and now two different excitable regimes, both Class I, are shown. The whole scenario is presented and discussed, showing that it is organized by three codimension-2 points. Moreover, the localized beam can be used to control important features, such as the excitable threshold, improving the possibilities for the experimental observation of this phenomenon.Comment: 9 Pages, 12 figure

    Site‐specific weed management—constraints and opportunities for the weed research community: Insights from a workshop

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    The adoption of site‐specific weed management (SSWM) technologies by farmers is not aligned with the scientific achievements in this field. While scientists have demonstrated significant success in real‐time weed identification, phenotyping and accurate weed mapping by using various sensors and platforms, the integration by farmers of SSWM and weed phenotyping tools into weed management protocols is limited. This gap was therefore a central topic of discussion at the most recent workshop of the SSWM Working Group arranged by the European Weed Research Society (EWRS). This insight paper aims to summarise the presentations and discussions of some of the workshop panels and to highlight different aspects of weed identification and spray application that were thought to hinder SSWM adoption. It also aims to share views and thoughts regarding steps that can be taken to facilitate future implementation of SSWM
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