Full control by locally induced relaxation

We demonstrate a scheme for controlling a large quantum system by acting on a small subsystem only. The local control is mediated to the larger system by some fixed coupling Hamiltonian. The scheme allows us to transfer arbitrary and unknown quantum states from a memory to the large system ("upload access") as well as the inverse ("download access"). We study the sufficient conditions of the coupling Hamiltonian and give lower bounds on the fidelities for downloading and uploading.     

A critical analysis of the hand and Othmer-Tobias correlations

Carniti, P., Cori, L. and Ragaini, V., 1978. A Critical Analysis of the Hand and Othmer-Tobias Correlations. Fluid Phase Equilibria, 2: 39–47.The Hand (H) and Othmer-Tobias (OT) correlations are extensively analyzed on 83 aqueous and 26 non-aqueous ternary systems. Twenty solutropic systems are also included. 65% and 58% of the systems give a linear correlation coefficient greater than 0.99 for H and OT respectively.An analysis of the sensitivity to systematic or random errors demonstrates the H correlation to be highly insensitive. A remarkable insensitivity, although not completly for some systematic errors, is also demonstrated for the OT correlation. However there is sufficient proof that they are both unsuitable as a check of experimental data, even though they are used for this purpose.The relation, not necessarily linear, derived from the H correlation, log(x₃₂/x₂₂) vs. log(x₃₁/x₁₁) is useful in locating the plait point.     

Thermodynamics of alcohols and monosaccharides in aqueous solutions of biuret at 25°C

The excess enthalpies of ternary aqueous solutions of biuret with four aliphatic alcohols or four isomeric pentoses have been determined by flow microcalorimetry at 25°C. The coefficients of the virial expansion of the excess enthalpies have been evaluated and compared with those already reported for urea and thiourea with the same alcohols and pentoses used here. For biuret-alcohol systems, the cross coefficients are positive and depend on the length and branching of the alkyl chain of the alcohols. On the contrary, they are negative for biuret-pentose systems. Hence, biuret, as urea and thioura, is able to differentiate the behavior of families of solutes characterized by the same functional groups. The results are interpreted in terms of the relative stabilities of the hydration cospheres of predominantly hydrophobic or predominantly hydrophilic cosolutes. However, hypotheses about the hydration cospheres of the saccharides, which are more complex than those used previously, seem to be necessary to rationalize their complete behavior in water.     

Comparison of mass spectrometric methods for studying thermally labile compounds: Rifapentine

Results of 16 different mass spectrometric ionization and sample-introduction methods are compared for the case of a thermally very labile antibiotic, rifapentine. These suggest that extensive thermal decomposition occurs during evaporation when the sample can come into contact with hot metal parts, usually the source housing. The intensity of the molecular ion and the extent of fragmentation depend on various parameters, such as the ionization process, positive or negative-ion detection and the type of sample introduction. The most informative methods for rifapentine seem to be ‘in-beam’ electron impact, negative ionization with particle beam and direct liquid introduction interfaces and positive- and negative-ion fast atom bombardment.     

Sensitizing effect of bio-based chemicals from urban wastes on the photodegradation of azo-dyes

To promote bio-based products for the industry, six bio-organic substances (cHALi) isolated from yard trimmings (green) and food (humid) urban residues aged under aerobic digestion for 0–60 days were investigated for their potential to perform as sensitizers for azo-dyes photodegradation. Ethylorange (EO) was used as probe molecule at 5 mg L^?1 starting concentration and irradiated in a closed Pyrex^® cell with a Xenon (1500 W) lamp and a cut-off filter for wavelengths below 340 nm or in a cylindrical photochemical reactor equipped with a 125 W medium pressure Hg lamp. The cHALi/EO ratio in the starting EO solution varied in the 0–200 (w/w) range. The % dye abatement was found a function of the irradiation time, of the type of cHALi substance and of the cHALi/EO ratio. The best results were achieved with cHALi isolated after 7 days biomass aerobic digestion. Total dye abatement was achieved within relatively short few hours. A progressive dye mineralization was observed under the same experimental conditions. On the contrary no significant degradation was evident for the cHALi substances within the same irradiation time. Several hydroxylated azo compounds were identified as likely responsible of residual color after total EO abatement. The results, coupled to the previously reported good performance of the same cHALi substances as auxiliaries for textile dyeing, augur well for the development of both efficient and environmentally friendly textile dyeing processes.     

An exact solution for one-dimensional unsteady nonlinear groundwater flow

After a brief review of the validity of Darcy's law, a nonlinear flow law is adopted for the analytical solution of a groundwater flow problem. A one-dimensional unsteady flow in plane geometry, with prescribed head at the boundaries, is studies. The solution of the analogous linear case is reviewed through the use of Boltzmann's transformation. A solution for nonlinear flow is obtained through a generalization of this transformation. Detailed expressions for specific discharge and drawdown are derived for two significant values of the exponent of the flow law. All results are presented in dimensionless form for a comparative analysis. Some significant cases are plotted. Finally, some implications of the adoption of a nonlinear flow law are discussed.

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Sommario Dopo un breve riepilogo sui limiti di validità della legge di Darcy, si adotta una formulazione non lineare della legge del moto per la risoluzione analitica di un problema di filtrazione. Si studia un moto non stazionario monodimensionale in geometria piana, con carico assegnato al contorno. Viene richiamata la soluzione dell'analogo caso lineare, tramite l'applicazione della trasformata di Boltzmann. Una soluzione per il moto non lineare è ottenuta mediante la generalizzazione di tale trasformazione. Si ricavano le espressioni della velocità apparente di filtrazione e del drawdown per due valori significativi dell'esponente della legge del moto. Tutti i risultati sono presentati in forma adimensionale per una analisi comparativa. Alcuni casi significativi sono diagrammati. In conclusione, sono discusse alcune implicazioni dell'adozione di una legge del moto non lineare.

     

High-Q factor single mode circular photonic crystal nano-resonator

In this work, the analysis, fabrication and optical characterization of a two-dimensional circular photonic crystal (2D-CPC) nano-resonator based on an air/GaAs/air slab waveguide are presented. Four InAs/InGaAs quantum dots (QDs) stacked layers emitting around 1300 nm at room temperature were embedded in a GaAs waveguide layer grown on an Al_0.7Ga_0.3As layer and GaAs substrate. The patterning of the structure and the membrane release were achieved by using electron beam lithography, ICP plasma etching and selective wet etching of the AlGaAs sacrificial layer. The micro-luminescence spectrum recorded from the fabricated nano-cavity shows a narrow optical transition at the resonance wavelength of about 1282 nm with a FWHM and Q-factor of 6.2 Å and more than 2000, respectively.     

Decomposition of the Kähler equation

It is shown that the Kähler equation in a four-dimensional pseudo-Riemannian manifold with Lorentzian signature decomposes uniquely into four uncoupled equations of Duffin type.