Small Domain Size Research Articles

Automated Search for Impossibility Theorems in Social Choice Theory: Ranking Sets of Objects

We present a method for using standard techniques from satisfiability checking to automatically verify and discover theorems in an area of economic theory known as ranking sets of objects. The key question in this area, which has important applications in social choice theory and decision making under uncertainty, is how to extend an agent's preferences over a number of objects to a preference relation over nonempty sets of such objects. Certain combinations of seemingly natural principles for this kind of preference extension can result in logical inconsistencies, which has led to a number of important impossibility theorems. We first prove a general result that shows that for a wide range of such principles, characterised by their syntactic form when expressed in a many-sorted first-order logic, any impossibility exhibited at a fixed (small) domain size will necessarily extend to the general case. We then show how to formulate candidates for impossibility theorems at a fixed domain size in propositional logic, which in turn enables us to automatically search for (general) impossibility theorems using a SAT solver. When applied to a space of 20 principles for preference extension familiar from the literature, this method yields a total of 84 impossibility theorems, including both known and nontrivial new results.

Recent developments on high Curie temperature PIN–PMN–PT ferroelectric crystals

Pb(In0.5Nb0.5)O3–Pb(Mg1/3Nb2/3)O3–PbTiO3 (PIN–PMN–PT) ferroelectric crystals attracted extensive attentions in last couple years, due to their higher usage temperatures range (>30°C) and coercive fields (∼5kV/cm), meanwhile maintaining similar electromechanical couplings (k33>90%) and piezoelectric coefficients (d33∼1500pC/N), when compared to their binary counterpart Pb(Mg1/3Nb2/3)O3–PbTiO3. In this article, we reviewed recent developments on the PIN–PMN–PT single crystals, including the Bridgman crystal growth, dielectric, electromechanical, piezoelectric and ferroelectric behaviors as functions of temperature and dc bias. Mechanical quality factor Q was studied as a function of orientation and phase. Of particular interest is the dynamic strain, which related to the Q and d33, was found to be improved when compared to the binary system, exhibiting the potential usage of PIN–PMN–PT in high power application. Furthermore, PIN–PMN–PT crystals exhibit improved thickness dependent properties, due to their small domain size, being on the order of 1μm. Finally, the manganese acceptor dopant in the ternary crystals was investigated and discussed briefly in this paper.

Effect of in situ-formed polydimethylsiloxane on the properties of polyimide hybrids

Polyimide-polydimethylsiloxane (PI-PDMS) hybrids were synthesized by combining an in situ sol–gel reaction of diethoxydimethylsilane (DEDMS) and imidization of poly(amide acid) (PAA) prepared from pyromellitic dianhydride (PMDA) and 4,4′-oxydianiline (ODA). Transparent hybrid films were obtained with up to 3 wt.% PDMS content corresponding to the relatively small domain size of PDMS as confirmed by scanning electron microscopy. The hybrid films with up to 3 wt.% of PDMS content showed higher tensile modulus, strength and elongation at break than those of pristine PI, due to the in situ-formed PDMS. The thermal stability of the hybrids also increased with the increase of PDMS content, as evidenced by TGA.

Transformation between dense and sparse spirals in symmetrical bistable media

Transformation between dense and sparse spirals is studied numerically based on a bistable FitzHugh–Nagumo model. It is found that the dense spiral can transform into two types of sparse spirals via a subcritical bifurcation: positive phase sparse spiral and negative phase sparse spiral. The choice of the two types of sparse spirals after the transformation is affected remarkably by the boundary effect if a small domain size is applied. Moreover, the boundary effect gives rise to novel meandering of sparse spiral with only outward petals.

Agonist-selective Dynamic Compartmentalization of Human Mu Opioid Receptor as Revealed by Resolutive FRAP Analysis

Techniques for analyzing the membrane diffusion of molecules are the most promising methods for investigating the compartmentalization of G-protein-coupled receptors, particularly as relevant to receptor signaling processes. Here, we report fluorescence recovery after photobleaching (FRAP) measurements performed at variable spot radius for human mu opioid (hMOP) receptors on SH-SY5Y neuroblastoma cells in the presence of ligands. Although an antagonist did not affect the behavior of the receptors compared with the basal state, two different agonists, DAMGO and morphine, caused markedly different changes to receptor diffusion. Like receptors in the absence of ligand, receptors bound to morphine exhibited diffusion confined to joined semipermeable domains, but with smaller domain size and diffusion coefficient. This effect was inhibited by pertussis toxin, strongly suggesting that this dynamic behavior is associated with early steps of signaling. In the presence of DAMGO, half of the receptors displayed free long-range diffusion and the other half were confined to smaller isolated domains. Hypertonic sucrose buffer suppressed this effect, which we attribute to receptor entry into clathrin-coated pits. It is likely that the observation of distinct receptor dynamics in the presence of DAMGO and morphine involves the agonist-selective phosphorylation of the receptor.

Polarization fatigue in Pb(In 0.5Nb 0.5)O 3–Pb(Mg 1/3Nb 2/3)O 3–PbTiO 3 single crystals

Electric fatigue tests have been conducted on pure and manganese-modified Pb(In 0.5Nb 0.5)O 3–Pb(Mg 1/3Nb 2/3)O 3–PbTiO 3 (PIN–PMN–PT) single crystals along different crystallographic directions. Polarization degradation was observed to suddenly occur above 50–100 bipolar cycles in 〈1 1 0〉 oriented samples, while 〈0 0 1〉 oriented samples exhibited almost fatigue free characteristics. The fatigue behavior was investigated as a function of orientation, magnitude of the electric field and manganese dopant. It was found that 〈0 0 1〉 oriented PIN–PMN–PT crystals were fatigue free, due to its small domain size, being on the order of 1 μm. The 〈1 1 0〉 direction exhibited a strong electrical fatigue behavior due to mechanical degradation. Micro/macro cracks developed in fatigued 〈1 1 0〉 oriented single crystals. Fatigue and cracks were the result of strong anisotropic piezoelectric stress and non-180° domain switching, which completely locked the non-180° domains. Furthermore, manganese-modified PIN–PMN–PT crystals were found to show improved fatigue behavior due to an enhanced coercive field.

Optimization of piezoelectric properties for [001](c) poled 0.94Pb(Zn(13)Nb(23))O(3)-0.06PbTiO(3) single crystals.

The piezoelectric properties of [001](c) poled 0.94Pb(Zn(13)Nb(23))O(3)-0.06PbTiO(3) single crystals were greatly enhanced by controlling their domain configurations. Contrary to the interpretation of charged domain walls being the main contributor to the piezoelectric enhancement, we found that smaller domain size and more neutral domain walls were the main contributors for the piezoelectric enhancement of these multidomain crystals. The properties of 109 degrees neutral domain walls in 0.94Pb(Zn(13)Nb(23))O(3)-0.06PbTiO(3) single crystals were extracted by using a piezoelectric domain wall model.

Influence of a Mesogenic Dendrimer on the Morphology of Polymer–Fullerene Composites for Photovoltaics

The efficiency of “bulk hetero junction”-type plastic solar cells depends crucially on the morphology of an entangled network of two immiscible compounds that serve as electron donor and electron acceptor, respectively. The present work describes preliminary results about the question how the luminescence and the morphology of a composite containing a fullerene C60 derivative and a p-phenylene vinylene (PPV) derivative are altered, when a dendrimer with a fullerene core and mesogenic side-chains is added. Fluorescence quenching and surface topography of the composites indicate that adding the mesogenic dendrimer can result in smaller domain sizes, which may be useful for photovoltaic applications.

Magnetic and ferroelectric properties of epitaxial Sr-doped [formula omitted] thin films

We investigate the magnetic and ferroelectric properties of epitaxial Sr-doped BiFeO 3, i.e., Bi 0.75Sr 0.25FeO 3−δ, thin films prepared by pulsed laser deposition. The films deposited at high oxygen pressure show a ferroelectric hysteresis loop at room temperature with remnant polarization of 2 P r = 86.13 μ C / cm 2 and coercive field of 2 E C = 75.5 kV / cm . Compared with the epitaxial BiFeO 3 thin film, the remnant polarization and coercive field of Bi 0.75Sr 0.25FeO 3−δ are small, probably due to the dilution of Bi 3+ ions, the existence of oxygen vacancies, and a small domain size. On the contrary, the films deposited at low oxygen pressure show a ferromagnetic hysteresis loop at room temperature. However, x-ray absorption and x-ray magnetic circular dichroism measurements show that the observed magnetic moment might be related to the formation of a γ - Fe 2O 3 impurity phase.

Structural characterization of C–S–H and C–A–S–H samples—Part I: Long-range order investigated by Rietveld analyses

Rietveld analyses on samples belonging to C–S–H and C–A–S–H series (0.8≤C/S≤1.7) were realized on X-ray powder patterns. The tobermorite M model was successfully used to refine all the powder patterns from C–S–H samples whatever the C/S value. This gives clear indication on the steady change in a unique structural description, corresponding to a ‘tobermorite M defect’ model, when passing from C–S–H(I) (C/S<1.0) to C–S–H(II) type (C/S>1.0). The possibility for both C–S–H types (from polymerized silicate chains to isolated silicate dimers) to accommodate the same structural model is explained by the continuous evolution of the occupancies of the cationic sites: the interlayer Ca atoms, the Si atoms from paired and bridging silicates. Accurate refinements of the structural and microstructural parameters evidenced the well crystallized feature of C–S–H phase combined with a small coherent domain size. Insertion of Al atoms in the C–S–H structure (C–A–S–H phase) involves a clear disruption into the layered atomic framework. The large increase of layer spacing observed when incorporating aluminum into C–S–H indicates that Al atoms should be located in the interlayer region of the structure in new crystallographic sites. Aluminum atoms are not substituted silicon crystallographic sites or interlayer calcium crystallographic sites.

Stability of monolayers and bilayers in a copolymer-homopolymer blend model

We study the stability of layered structures in a variational model for diblock copolymerhomopolymer blends with respect to perturbations of their interfaces. The main step consists of calculating the first and second derivatives of a sharp-interface Ohta–Kawasaki energy for straight mono- and bilayers and determining the sign of the latter. By developing the interface perturbations in a Fourier series we fully characterise the stability of the structures in terms of the energy parameters. Both for the monolayer and for the bilayer there exist parameter regions where these structures are unstable. For strong repulsive interaction between the monomer types in the diblock copolymer the bilayer is always stable with respect to interface perturbations, irrespective of the domain size. The monolayer is only stable for small domain size. In the course of our computations we also give a Green’s function for the Laplacian on a twodimensional periodic strip.

Morphology and interaction between lipid domains

Cellular membranes are a heterogeneous mix of lipids, proteins and small molecules. Special groupings enriched in saturated lipids and cholesterol form liquid-ordered domains, known as "lipid rafts," thought to serve as platforms for signaling, trafficking and material transport throughout the secretory pathway. Questions remain as to how the cell maintains small fluid lipid domains, through time, on a length scale consistent with the fact that no large-scale phase separation is observed. Motivated by these examples, we have utilized a combination of mechanical modeling and in vitro experiments to show that membrane morphology plays a key role in maintaining small domain sizes and organizing domains in a model membrane. We demonstrate that lipid domains can adopt a flat or dimpled morphology, where the latter facilitates a repulsive interaction that slows coalescence and helps regulate domain size and tends to laterally organize domains in the membrane.

The effect of interfacial adhesion on the impact strength of immiscible PP/PETG blends compatibilized with triblock copolymers

Abstract In this work, recycled Poly(ethylene glycol-co-cyclohexane-1,4-dimethanol terephthalate) plastic (PETG) was used to enhance the properties and lower the cost of polypropylene(PP). In order to adjust the interfacial adhesion, three triblock copolymers having the same styrene block at two ends but different block in the middle, were used a the compatibilizers, namely, styrene–ethylene/butylene–styrene (SEBS), styrene–butadiene–styrene (SBS), styrene–isoprene–styrene (SIS). The ratio of PP to PETG was fixed at 70/30 and the relationship between interfacial adhesion and mechanical properties was investigated. The addition of SIS caused a considerable increase in Izod impact toughness, but only slightly improved toughness was observed for blends compatibilized with SEBS. The effect of SBS on improving the impact toughness lied in between that of SIS and SEBS. SEM micrographs showed that PETG forms a fibrillar-like structure for all the uncompatibilized and compatibilized blends, and the blends compatibilized with SBS have smallest domain size, the blends compatibilized with SEBS have largest domain size, while the ones compatibilized with SIS show a moderate domain size. Results from melt rheometry and SEM observation together with work of interfacial adhesion, indicated a strongest interfacial adhesion in blends compatibilized with SBS, poorest in blends compatibilized with SEBS, and moderate in blends compatibilized with SIS. It is very interesting to found that the much improved impact strength was not observed in the blends with the strongest interfacial adhesion but achieved in the blend with moderate interfacial adhesion. Investigation on the impact fractured surface revealed an easier debonding of fibril from matrix and consequently drawn out of matrix in blends compatibilized by SIS with moderate interfacial adhesion, which was considered as the main reason for the much improved impact toughness in this system.

Influence of Growth Temperature on the Characteristics of Ga-Doped ZnO Thin Films Deposited by Magnetron Sputtering

Ga-dope ZnO (ZnO:Ga) thin films with n-type semiconducting behavior were grown on c-sapphire substrates by radio frequency magnetron sputtering at various growth temperatures. The room temperature grown ZnO:Ga film showed a slight preferred orientation along the c-axis with small domain size and high density of stacking faults. The increase in growth temperature from 300 to 550 °C resulted in the growth of granular shaped epitaxial ZnO:Ga films due to insufficient thermal energy and large lattice mismatch. The films grown at above 550 °C showed a flat surface with the simultaneous improvement of the electrical carrier concentration and carrier mobility (6.3×1018/cm-3 and 27 cm2 V-1 s-1, respectively). In addition, there was an increase in the grain size and a decrease in the dislocation density in the high temperature grown films. The low-temperature photoluminescence of the ZnO:Ga films grown at <450 °C showed the redshift in deep-level emission, which was attributed to a transition from Zni to Oi level.

Nanodomains in Fe+3-doped lead zirconate titanate ceramics at the morphotropic phase boundary do not correlate with high properties

Configuration of domain walls in undoped and Fe+3-doped lead zirconate titanate (PZT) ceramics at the morphotropic phase boundary has been investigated by the transmission electron microscopy. The distance between domain walls in undoped PZT is on the order of hundreds of nanometers and is drastically reduced to tens of nanometers by acceptor doping. The properties of doped and undoped samples are compared and discussed in terms of domain size, phase mixture, and presence of dopants. It is suggested that the small domain size cannot be a dominant effect in the enhancement of the properties in morphotropic PZT.

Incommensurately modulated LT″-Ni 1+δSn ( δ=0.60, 0.63): Rietveld refinement, line-broadening analysis and structural relation with LT- and LT′-Ni 1+δSn

X-ray powder diffraction data of NiAs/Ni 2In-type Ni 1.60Sn and Ni 1.63Sn alloys annealed at or below about 573 K reveal the development of an incommensurately ordered phase called LT″. In this phase Ni(2) atoms occupy partially the trigonal–bipyramidal interstices formed by five Sn within an NiAs-type arrangement Ni(1)Sn. The modulated occupational ordering of Ni(2) in the LT″ phase can be described in the superspace group Cmcm( α00)0 s 0, and the parameters describing this occupational modulation were refined together with atomic displacement modulations using the Rietveld method. The structure parameters revealed close structural analogies of the LT″ phase with the previously reported commensurate LT-Ni 1+ δ Sn and incommensurate LT′-Ni 1+ δ Sn phases (A. Leineweber, J. Solid State Chem. 177 (2004) 1197–1212), which both occur for lower Ni contents than the LT″ phase. The 1st-order satellite reflections visible in the powder-diffraction patterns exhibit, with respect to the fundamental reflections, a considerable diffraction-line broadening, caused by a small size of the particularly ordered domains. This small-domain-size broadening was successfully described by a recently developed reflection-index ( hklm) dependent (anisotropic) line-broadening model (A. Leineweber, V. Petricek, J. Appl. Crystallogr. 40 (2007) 1027–1034) designed to consider the effect of fluctuations of the lattice metrics on the peak widths in powder diffraction patterns of incommensurately modulated crystal structures. The small domain sizes encountered for the LT″ phase indicate that domain coarsening is much more difficult than for the LT and LT′ phases. This special feature of the LT″ phase goes along with a compared to the LT and LT′ phases absent orthorhombic distortion and the low ordering temperature, which are discussed as a consequence of the ordering patterns due to the Ni(2) atoms.

Horizontal diffusion by submeso motions in the stable boundary layer

Four networks of wind data are used to construct the first systematic estimates of the horizontal diffusivity from observations of submeso motions on scales often unresolved in numerical models. Currently, the horizontal diffusivity in numerical models is specified mainly for numerical reasons without observational support. The data analysis in this study emphasizes the stable boundary layer although results are briefly presented for the unstable boundary layer. The horizontal diffusivity is estimated from the horizontal gradient and the observed flux. Horizontal gradients of scalars are generally difficult to directly estimate from observations with sufficient accuracy for much of the data. As an alternative, simulated particles with conservative properties are introduced into the observed wind field in order to estimate the horizontal diffusivity for submeso motions. The sensitivity of the horizontal diffusivity to details of the method is examined. The horizontal diffusivity increases with the range of time and space scales that are included in the evaluation. The horizontal diffusivity is much larger with significant topography and may increase with wind speed, depending on the site location. The coarse station spacing or the small domain size is found to be a major limitation to the analysis.

Surface Layer Characteristics of TiB&lt;SUB&gt;2&lt;/SUB&gt;/Al Composite by Stress Peening

The effect of stress peening on the surface layer characteristics of the TiB 2 /6351Al Composite including residual stress, microhardness and microstructures were investigated. The results show that the compressive residual stresses and microhardness were improved by stress peening. Microstructures investigation showed that, the deformation amount increased by stress peening which results in smaller domain size and higher density dislocations/microstrain. The more reinforcements distributed in the matrix played an important role in the compressive residual stresses increments and microstructures improvements. Stress peening is an effective method to improve the compressive residual stresses and the work-hardened state of the TiB 2 /6351Al Composite.

Enhanced electrochemical lithium storage activity of LiCrO2 by size effect

Download options Please wait... Supplementary files TEM images; rate performance data; GITT data; voltageprofiles; XRD data; XPS data PDF (1317K) Article information DOI https://doi.org/10.1039/B817624H Article type Paper Submitted 08 Oct 2008 Accepted 05 Feb 2009 First published 11 Mar 2009 Download Citation J. Mater. Chem., 2009,19, 2993-2998 BibTex EndNote MEDLINE ProCite ReferenceManager RefWorks RIS Permissions Request permissions Enhanced electrochemical lithium storage activity of LiCrO2 by size effect G. X. Feng, L. F. Li, J. Y. Liu, N. Liu, H. Li, X. Q. Yang, X. J. Huang, L. Q. Chen, K. W. Nam and W. S. Yoon, J. Mater. Chem., 2009, 19, 2993 DOI: 10.1039/B817624H To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page. If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given. If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page. Read more about how to correctly acknowledge RSC content. Search articles by author G. X. Feng L. F. Li J. Y. Liu N. Liu H. Li X. Q. Yang X. J. Huang L. Q. Chen K. W. Nam W. S. Yoon

Scale effect on statistics of the macrophysical properties of trade wind cumuli over the tropical western Atlantic during RICO

This study investigates the effect of observational domain size and pixel resolution on the statistics of macrophysical properties of trade wind cumulus clouds over the tropical western Atlantic. In order to better facilitate comparison with model simulations, the results are presented as an extension of earlier work by Zhao and Di Girolamo (2007), who have analyzed 152 Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) scenes collected between September and December 2004 to generate comprehensive statistics of cumulus clouds at the original 60 km × 60 km domain and 15 m pixel resolution of the data. The statistics change with domain size because as the domain size becomes smaller, (1) the probability of chopping clouds by the domain boundaries into smaller clouds increases, and (2) the probability of having cloudier and clearer domains increases. In addition, degrading pixel resolution results in (1) an amalgamation of smaller clouds into larger clouds, and (2) an increase in the frequency of partially filled cloudy pixels. The mean cloud fraction in our ASTER data set increases more than fourfold, with the total number of clouds reducing 26‐fold, when pixel resolution degrades from 15 m to ∼1 km. The cloud fraction frequency distribution becomes wider with a shift of the peak toward higher values at coarser resolution. However, at smaller domain sizes, the shift of the peak toward larger values due to pixel effects is overcompensated by the increase in frequency of smaller cloud fractions. The change in cloud size distribution is significant at domains smaller than 10 km × 10 km. An increase in the cloud size at coarser resolution shifts the peak of the size distribution toward larger values. At 15 m resolution, 98% of clouds are distributed at distances less than 300 m, with a peak in the nearest‐neighbor distance at less than 50 m at all domain sizes. The peak of the nearest‐neighbor distribution becomes wider and shifts to larger distances at coarser resolution. These results clearly indicate the importance of considering scale effect when comparing cloud resolving model simulations of trade wind cumuli with observations.