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51.
Environmental certification is becoming the main tool for application of sustainable development principles. The European Regulation Emas and the international standard ISO 14001 both require for certification, to perform an environmental management system to prevent environmental impacts and to continuously improve environmental performance. For a good environmental performance evaluation (EPE), certification needs to use scientific methodologies and to interface with scientific research; here we proposed emergy analysis as a valid method for EPE and emergetic environmental performance and condition indicators (EPIs, ECIs) to monitor a territorial system: Ravenna province (Italy). Together with emergy indicators were selected other indicators for a deeper EPE: emitted/adsorbed CO2, energy consumptions, air and water pollution measures. The paper showed that Ravenna system has a good environmental performance and demonstrated how different indicators from the most advanced chemical research (chemical-physical, analytical, etc.) contribute to a complete EPE of a complex territorial system and are useful for environmental certification and sustainable development.  相似文献   
52.
An ab initio Hartree–Fock method devoted to the study of polymers is presented, truncation criteria for the exchange and the Coulomb series are discussed, and it is shown that the error in the total energy evaluation can be reduced to below 0.0001 a.u./cell with little computational effort. Results for six polyacetylene isomers are presented and compared with previous ab initio data obtained using the same basis set. In agreement with the experimental findings, the alternating all-trans structure is the most stable.  相似文献   
53.
Bearing in mind the insight into the Hohenberg–Kohn theorem for Coulomb systems provided recently by Kryachko (Int J Quantum Chem 103:818, 2005), we present a re-statement of this theorem through an elaboration on Lieb’s proof as well as an extension of this theorem to finite subspaces. Contribution to the Serafin Fraga Memorial Issue.  相似文献   
54.
Central European Journal of Operations Research - Disaster management generally includes the post-disaster stage, which consists of the actions taken in response to the disaster damages. These...  相似文献   
55.
Some algebraic structures determined by the class (þ) of all effects of a Hilbert space þ and by some subclasses of (þ) are investigated, in particular de Morgan-Brouwer-Zadeh posets [it is proved that (þ n )(n<) has such a structure], Brouwer-Zadeh * posets (a quite trivial example consisting of suitable effects is given), and Brouwer-Zadeh 3 posets which are both de Morgan and *.It is shown that a nontrivial class of effects of a Hilbert space exists which is a BZ 3 poset. An -preclusivity relation on the set of all vectors of þ is introduced, and it is shown that it satisfies the regularity condition also for [1/2, 1].  相似文献   
56.
In a theory of local field algebras satisfying the split property, we introduce an algebra generated by the local energy-momentum operators obtained from the canonical local implementation of translations, and possibly by the local charges operators. We discuss the relations of this algebra to the given algebra of local observables and take some steps toward the characterization of theories where they coincide. In the presence of spontaneously broken symmetries, we present a no-go theorem.  相似文献   
57.
The decay rates for the exclusiveB decaysBK c andBK* c are calculated in the context of the heavy quark effective theory. We obtain(BK c )/ (BK)=1.6±0.2 and(BK* c )/ (K*)=0.39±0.04. These results lead to estimates BR(BK c )=(0.11±0.02)% and BR(BK* c )=(0.05±0.01)% if we use the central current experimental values forB(K, K *) branching ratios.  相似文献   
58.
59.
A lagrangian euclidean model of Drinfeld-Sokolov (DS) reduction leading to generalW-algebras on a Riemann surface of any genus is presented. The background geometry is given by the DS principal bundleK associated to a complex Lie groupG and anSL(2,) subgroupS. The basic fields are a hermitian fiber metricH ofK and a (0, 1) Koszul gauge fieldA * ofK valued in a certain negative graded subalgebrar ofg related tos. The action governing theH andA * dynamics is the effective action of a DS field theory in the geometric background specified byH andA *. Quantization ofH andA * implements on one hand the DS reduction and on the other defines a novel model of 2d gravity, DS gravity. The gauge fixing of the DS gauge symmetry yields an integration on a moduli space of DS gauge equivalence classes ofA * configurations, the DS moduli space. The model has a residual gauge symmetry associated to the DS gauge transformations leaving a given fieldA * invariant. This is the DS counterpart of conformal symmetry. Conformal invariance and certain non-perturbative features of the model are discussed in detail.  相似文献   
60.
We study some global projective properties of real plane curves with cusps, beaks and normal crossings. Starting from Fabricius-Bjerre's formula on the singularities of a curve in an affine plane, we describe its extension to a projective setting. Given a curve RP2, by fixing a base point we associate some indices to its singularities and double tangents. We prove two global relations linking these entities together.  相似文献   
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