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991.
992.
Patrizio Lecca Martin Christensen Andrea Conte Giovanni Mandras Simone Salotti 《Papers in Regional Science》2020,99(1):165-182
The paper illustrates the effect of a permanent demand-side shock in the perturbed regions and the associated spillover effects in the non-perturbed regions using a spatial-numerical general equilibrium model of the EU economy. We test to what extent gradual upward pressure on wages generated by a domestic increase in demand alters the magnitude of the economic impacts in the long-run and the degree to which this could result in changes in trade patterns. We also assess the size and the direction of the effects with varying trade substitution elasticities and under both perfectly and imperfectly competitive product markets. 相似文献
993.
EU-wide monitoring survey on emerging polar organic contaminants in wastewater treatment plant effluents 总被引:1,自引:0,他引:1
Robert Loos Raquel Carvalho Diana C. António Sara Comero Giovanni Locoro Simona Tavazzi Bruno Paracchini Michela Ghiani Teresa Lettieri Ludek Blaha Barbora Jarosova Stefan Voorspoels Kelly Servaes Peter Haglund Jerker Fick Richard H. Lindberg David Schwesig Bernd M. Gawlik 《Water research》2013
In the year 2010, effluents from 90 European wastewater treatment plants (WWTPs) were analyzed for 156 polar organic chemical contaminants. The analyses were complemented by effect-based monitoring approaches aiming at estrogenicity and dioxin-like toxicity analyzed by in vitro reporter gene bioassays, and yeast and diatom culture acute toxicity optical bioassays. Analyses of organic substances were performed by solid-phase extraction (SPE) or liquid–liquid extraction (LLE) followed by liquid chromatography tandem mass spectrometry (LC-MS-MS) or gas chromatography high-resolution mass spectrometry (GC-HRMS). Target microcontaminants were pharmaceuticals and personal care products (PPCPs), veterinary (antibiotic) drugs, perfluoroalkyl substances (PFASs), organophosphate ester flame retardants, pesticides (and some metabolites), industrial chemicals such as benzotriazoles (corrosion inhibitors), iodinated x-ray contrast agents, and gadolinium magnetic resonance imaging agents; in addition biological endpoints were measured. The obtained results show the presence of 125 substances (80% of the target compounds) in European wastewater effluents, in concentrations ranging from low nanograms to milligrams per liter. These results allow for an estimation to be made of a European median level for the chemicals investigated in WWTP effluents. The most relevant compounds in the effluent waters with the highest median concentration levels were the artificial sweeteners acesulfame and sucralose, benzotriazoles (corrosion inhibitors), several organophosphate ester flame retardants and plasticizers (e.g. tris(2-chloroisopropyl)phosphate; TCPP), pharmaceutical compounds such as carbamazepine, tramadol, telmisartan, venlafaxine, irbesartan, fluconazole, oxazepam, fexofenadine, diclofenac, citalopram, codeine, bisoprolol, eprosartan, the antibiotics trimethoprim, ciprofloxacine, sulfamethoxazole, and clindamycine, the insect repellent N,N′-diethyltoluamide (DEET), the pesticides MCPA and mecoprop, perfluoroalkyl substances (such as PFOS and PFOA), caffeine, and gadolinium. 相似文献
994.
The spatial activity patterns of firms in a multi-regional system are closely connected with the structure and evolution of
regional labour markets. Based on an extensive data set (cross-section) on commuting flows in Germany, this paper aims to
identify the relationship between entrepreneurial activity and spatial labour markets, by employing in particular the concept
of ‘entrepreneurial city’. A network connectivity model is adopted to assess connectivity patterns, using the power-law and
exponential law as a statistical test framework, in order to detect the presence of economic activity hubs that may resemble
the concept of entrepreneurial cities. Various results are presented and interpreted in the final part of the paper. 相似文献
995.
996.
Summary The viscoelastic behaviour of a bisphenol A polycarbonate after yielding is described by means of empirical superposition of coordinates along both time and stress axis, which allow collecting stress relaxation data, taken both in tension and in compression, into a master curve. 相似文献
997.
998.
The purpose of this paper is to propose a formal framework for structuring and embedding the heuristic information, in order to allow an algorithmic computation, in quite general cases, of the evaluation function of the classical Hart-Nilsson-Raphael algorithm. The notion of semantic graph is first introduced, in which the atomic notion of node is expanded by associating to it an internal structure where the heuristic information is inserted. It is proved that can be computed by solving an auxiliary problem, obtained from the original one by adding new arcs, and of smaller complexity than that onw. A new algorithm is then defined for the computation of and for the determination of minimal solutions. The validity of the model proposed is discussed in detail. 相似文献
999.
Arash A. Mostofi Jonathan R. Yates Giovanni Pizzi Young-Su Lee Ivo Souza David Vanderbilt Nicola Marzari 《Computer Physics Communications》2014
wannier90 is a program for calculating maximally-localised Wannier functions (MLWFs) from a set of Bloch energy bands that may or may not be attached to or mixed with other bands. The formalism works by minimising the total spread of the MLWFs in real space. This is done in the space of unitary matrices that describe rotations of the Bloch bands at each k-point. As a result, wannier90 is independent of the basis set used in the underlying calculation to obtain the Bloch states. Therefore, it may be interfaced straightforwardly to any electronic structure code. The locality of MLWFs can be exploited to compute band-structure, density of states and Fermi surfaces at modest computational cost. Furthermore, wannier90 is able to output MLWFs for visualisation and other post-processing purposes. Wannier functions are already used in a wide variety of applications. These include analysis of chemical bonding in real space; calculation of dielectric properties via the modern theory of polarisation; and as an accurate and minimal basis set in the construction of model Hamiltonians for large-scale systems, in linear-scaling quantum Monte Carlo calculations, and for efficient computation of material properties, such as the anomalous Hall coefficient. We present here an updated version of wannier90, wannier90 2.0, including minor bug fixes and parallel (MPI) execution for band-structure interpolation and the calculation of properties such as density of states, Berry curvature and orbital magnetisation. wannier90 is freely available under the GNU General Public License from http://www.wannier.org/. 相似文献
1000.
Walter Gianelli Giovanni Camino Nadka Tzankova Dintcheva Stella Lo Verso Francesco Paolo La Mantia 《大分子材料与工程》2004,289(3):238-244
Summary: The aim of this study is to examine the effect of the compounding apparatus and of processing conditions on the properties of an organoclay‐poly[ethylene‐co‐(vinyl acetate)] (EVA) nanocomposite. The filled materials were prepared using either a discontinuous batch mixer, a single screw extruder, a counter rotating intermeshing twin‐screw compounder or a corotating intermeshing twin‐screw extruder. The characterization of the obtained nanocomposites was performed by XRD, thermogravimetry, mechanical and rheological measurements. The study has shown the possibility of producing nanocomposites based on EVA and a commercial organoclay (Cloisite 15A) by several mixing equipments. In fact all the prepared composite materials exhibit a larger interlayer clay spacing in comparison with the pristine organoclay. Moreover their elastic modulus is significantly increased from 50 to 100% depending on the processing conditions.