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Complete Characterization (complete + characterization)
Selected AbstractsComplete Characterization of Thermoelectric Materials by a Combined van der Pauw ApproachADVANCED MATERIALS, Issue 38 2010Johannes de Boor Thermoelectric materials can convert waste heat directly into electrical power and represent an important contribution to lessen energy scarcity. Here we present a novel, simple and inexpensive approach for a complete thermoelectric characterization, by which all relevant quantities, like the electrical conductivity, the thermal conductivity, the Seebeck coefficient, and the figure of merit, can be determined directly. [source] "Breathing" in Adsorbate-Responsive Metal Tetraphosphonate Hybrid MaterialsCHEMISTRY - A EUROPEAN JOURNAL, Issue 27 2009Rosario M. Abstract Breathe easy: Reversible H2O and NH3 gas uptake by 2D calcium tetraphosphonates (see figure) is accompanied by framework structural changes similar to those previously reported for some carboxylate-based hybrids. This breathing mechanism is accompanied by a volume increase of 55,%, while maintaining the topology and crystallinity of the material. The structures of various layered calcium tetraphosphonates (CaH6DTMP; H8DTMP=hexamethylenediamine tetrakis(methylenephosphonic acid)), have been determined. Starting from CaH6DTMP,2H2O, thermal treatment and subsequent exposure to NH3 and/or H2O vapors led to four new compounds that showed high storage capacity of guest species between the layers (up to ten H2O/NH3 molecules) and a maximum volume increase of 55,%. The basic building block for these phosphonates consists of an eight-membered ring chelating Ca2+ through two phoshonate groups, and the organic ligand is located within the layers, which are held together by hydrogen bonds. The structural analysis revealed that the uptake/removal of guest species (H2O and NH3) induces significant changes in the framework not only by changing the interlayer distances but also through important conformational changes of the organic ligand. An anisotropic breathing motion could be quantified by the changes of the unit-cell dimensions and ligand arrangements in four crystalline derivatives. Complete characterization revealed the existence of interconversion reactions between the different phases upon gas uptake and release. The observed behavior represents, to the best of our knowledge, the first example of a breathing-like mechanism in metal phosphonates that possess a 2D topology. [source] Head-to-Head Right-Handed Cross-Links of the Antitumor-Active Bis(,- N,N,-di- p -tolylformamidinato)dirhodium(II,II) Unit with the Dinucleotides d(GpA) and d(ApG)CHEMISTRY - A EUROPEAN JOURNAL, Issue 32 2008Helen Abstract Reactions of cis -[Rh2(DTolF)2(NCCH3)6](BF4)2 with the dinucleotides d(GpA) and d(ApG) proceed to form [Rh2(DTolF)2{d(GpA)}] and [Rh2(DTolF)2{d(ApG)}], respectively, with bridging purine bases spanning the Rh,Rh unit in the equatorial positions. Both dirhodium adducts exhibit head-to-head (HH) arrangement of the bases, as indicated by the presence of H8/H8 NOE cross-peaks in the 2D ROESY NMR spectra. The guanine bases bind to the dirhodium core at positions N7 and O6, a conclusion that is supported by the absence of N7 protonation at low pH,values and the notable increase in the acidity of the guanine N1H sites (pKa,7.4 in 4:1 CD3CN/D2O), inferred from the pH-dependence titrations of the guanine H8 proton resonances. In both dirhodium adducts, the adenine bases coordinate to the metal atoms through N6 and N7, which induces stabilization of the rare imino tautomer of the bases with a concomitant substantial decrease in the basicity of the N1H adenine sites (pKa,7.0,7.1 in 4:1 CD3CN/D2O), as compared to the imino form of free adenosine. The presence of the adenine bases in the rare imino form is further corroborated by the observation of DQF-COSY H2/N1H and ROE N1H/N6H cross-peaks in the 2D NMR spectra of [Rh2(DTolF)2{d(GpA)}] and [Rh2(DTolF)2{d(ApG)}] in CD3CN at ,38,°C. The 2D NMR spectroscopic data and the molecular modeling results suggest the presence of right-handed variants, HH1R, in solution for both adducts (HH1R refers to the relative base canting and the direction of propagation of the phosphodiester backbone with respect to the 5, base). Complete characterization of [Rh2(DTolF)2{d(GpA)}] and [Rh2(DTolF)2{d(ApG)}] by 2D,NMR spectroscopy and molecular modeling supports anti- orientation of the sugar residues for both adducts about the glycosyl bonds as well as N- and S-type conformations for the 5,- and 3,-deoxyribose residues, respectively. [source] Head-to-Head Cross-Linked Adduct between the Antitumor Unit Bis(,- N,N,-di- p -tolylformamidinato)dirhodium(II,II) and the DNA Fragment d(GpG)CHEMISTRY - A EUROPEAN JOURNAL, Issue 25 2006Helen T. Chifotides Dr. Abstract Reactions of the compound cis -[Rh2(DTolF)2(CH3CN)6](BF4)2, a formamidinate derivative of the class of antitumor compounds [Rh2(O2CR)4] (R=Me, Et, Pr), with 9-ethylguanine (9-EtGuaH) or the dinucleotide d(GpG) proceed by substitution of the acetonitrile groups, with the guanine bases spanning the RhRh bond, in a bridging fashion, through sites N7/O6. In the case of 9-EtGuaH, both head-to-head (HH) and head-to-tail (HT) isomers are formed, whereas with the tethered bases in d(GpG), only one right-handed conformer HH1R [Rh2(DTolF)2{d(GpG)}] is present in solution. For both cis -[Rh2(DTolF)2(9-EtGuaH)2](BF4)2 and [Rh2(DTolF)2{d(GpG)}], the absence of N7 protonation at low pH and the substantial decrease of the pKa values for N1-H deprotonation, support N7/O6 binding of the bases to the dirhodium core. The N7/O6 binding of the bases is further corroborated by the downfield shift by ,,,4.0 ppm of the 13C NMR resonances for the C6 nuclei as compared to the corresponding resonances of the free ligands. The HH arrangement of the guanine bases in [Rh2(DTolF)2{d(GpG)}] is indicated by the intense H8/H8 ROE cross-peaks in the 2D ROESY NMR spectrum. Complete characterization of the [Rh2(DTolF)2{d(GpG)}] conformer by 2D NMR spectroscopy supports anti- orientation and N (C3,- endo) conformation for both deoxyribose residues. The N-pucker for the 5,-G base is universal in such cross-links, but it is very unusual for platinum and unprecedented for dirhodium HH cross-linked adducts to have both deoxyribose residues in the N-type conformation. The bulk, the nonlabile character, and the electron-donating ability of the formamidinate bridging groups spanning the dirhodium core affect the nature of the preferred dirhodium DNA adducts. Molecular modeling studies performed on [Rh2(DTolF)2{d(GpG)}] corroborate the structural features obtained by NMR spectroscopy. [source] Principles of Highly Resolved Determination of Texture and Microstructure using High-Energy Synchrotron Radiation,ADVANCED ENGINEERING MATERIALS, Issue 6 2009Helmut Klein Abstract Diffraction imaging with hard X-rays (high-energy synchrotron radiation) using the detector sweeping techniques allows measurement of the texture and microstructure of polycrystalline materials with high orientation- and location-resolution. These techniques provide continuous two-dimensional images of different sections and projections of the six-dimensional "orientation-location" space. For the high orientation resolution case, it is possible to measure the orientation and location coordinates of up to 105 individual grains simultaneously. From these parameters, the grain size and shape can also be obtained, yielding the complete orientation stereology of the polycrystalline aggregate, which is required for its complete characterization. For the high location resolution case, the intensity at any point of the diagrams corresponds to a pole density as a function of the orientation-location space. [source] Thermodynamic analysis of binding of p -substituted benzamidines to trypsinFEBS JOURNAL, Issue 6 2001Reinskje Talhout Understanding the structural basis of inhibitor,enzyme interactions, important for the design of new drugs, requires a complete thermodynamic characterization of the binding process as well as a description of the structure of the complex. In this paper, the binding of p -substituted benzamidinium derivatives to the structurally well-characterized serine proteinase bovine pancreatic trypsin has been studied using isothermal titration calorimetry. These experiments have permitted a complete characterization of the temperature dependence of the inhibitor-binding thermodynamics. At 25 °C, both the enthalpy and entropy of binding are favourable for all studied derivatives, but this is only true for a relatively narrow temperature range. As binding is characterized by a negative change in heat capacity, the process is characterized by enthalpy,entropy compensation, resulting in a change of the net thermodynamic driving force for association from entropic to enthalpic with increasing temperature. These phenomena are not unusual when hydrophobic forces play an important role. The trend in the relative binding potencies can, to a significant extent, be attributed to the electron-donating/withdrawing character of the substituent at the para position, as shown by the Hammett plot for the different inhibitors; the more polar the p -substituted benzamidine, the less potent it will be as a trypsin inhibitor. This behaviour might result from a bulk solvation effect, meaning that the more polar, lower potency inhibitors will be more stabilized in water than the less polar, higher potency inhibitors. [source] Strain Mapping at the Atomic Scale in Highly Mismatched Heterointerfaces,ADVANCED FUNCTIONAL MATERIALS, Issue 14 2007M. Sánchez Abstract A complete characterization of dislocation network in a highly mismatched interface with high spatial resolution has been performed. The interface between InN quantum dots and a (0001) GaN substrate contains three noninteracting sets of regularly-spaced misfit dislocations lying along <110> directions. The network has a "Star of David" form, with each star bounding a hexagonal region which is pseudomorphic. These misfit dislocations form a threading dislocation network at the island edges due to free surface forces. [source] NMR Characterization of Complex p- Oligophenyl Scaffolds by Means of Aliasing Techniques to Obtain Resolution-Enhanced Two-Dimensional SpectraHELVETICA CHIMICA ACTA, Issue 9 2004Damien Jeannerat The usefulness of computer-assisted aliasing to secure maximal resolution of signal clusters in 1H- and 13C-NMR spectra (which is essential for structure determination by HMBC 2D NMR spectroscopy) in minimal acquisition time is exemplified by the complete characterization of the two complementary p -octiphenyls 1 and 2 with complex substitution patterns. The need for digital resolution near 1,Hz/pt to dissect the extensive signal clusters in the NMR spectra of these refined oligomers excluded structure determination under routine conditions. High resolution was secured by exploiting the low signal density in the 13C dimension of HMBC spectra by using computer-assisted aliasing to maximize signal density. Based on the observed shifts in DEPT and 1H-decoupled 13C-NMR spectra of 1 and 2, computer-assisted aliasing allowed to reduce the number of required time increments by a factor of 20 to 30 compared to full-width spectra with identical resolution. Without signal-to-noise constraints, this computer-assisted aliasing reduced the acquisition time for high-resolution NMR spectra needed for complete characterization of refined oligomers 1 and 2 by the same factor (e.g., from over a day to about an hour). With resolved signal clusters in fully aliased HSQC and HMBC spectra, unproblematic structure determination of 1 and 2 is demonstrated by unambiguous assignment of all C- and H-atoms. These findings demonstrate that computer-assisted aliasing of the underexploited 13C dimension makes extensive molecular complexity accessible by conventional multidimensional heteronuclear NMR experiments without extraordinary efforts. [source] Transplants and Implants: The Economics of Self-ImprovementINTERNATIONAL ECONOMIC REVIEW, Issue 3 2001Ken Burdett This article examines equilibrium self-improvement and marriage proposal strategies in a two-sided search model with nontransferable utility. Singles are vertically differentiated,some make better marriage partners than others. A complete characterization of equilibrium is provided. It is shown there are two externalities to self-improvement decisions. Further, these externalities may support multiple Pareto rankable equilibria. By encouraging everybody to self-improve, society can create a situation where everybody is forced to improve to remain "acceptable." But a preferred equilibrium may exist where there is less (costly) self-improvement. [source] A bounding surface plasticity model for cyclic loading of granular soilsINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 14 2005N. Khalili Abstract A constitutive model for describing the stress,strain behaviour of granular soils subjected to cyclic loading is presented. The model is formulated using bounding surface theory within a critical state framework. A single set of material parameters is introduced for the complete characterization of the constitutive model. The shape of the bounding surface is based on experimental observations of undrained stress paths for loose samples. A mapping rule which passes through stress reversal points is introduced to depict the stress,strain behaviour during unloading and reloading. The effect of particle crushing is considered through a modified critical state line. Essential features of the model are validated using several experimental data from the literature. Both drained and undrained loading conditions are considered. The characteristic features of behaviour in granular soils subjected to cyclic loading are captured. Copyright © 2005 John Wiley & Sons, Ltd. [source] Addressing agent loss in vehicle formations and sensor networksINTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL, Issue 15 2009Tyler H. Summers Abstract In this paper, we address the problem of agent loss in vehicle formations and sensor networks via two separate approaches: (1) perform a ,self-repair' operation in the event of agent loss to recover desirable information architecture properties or (2) introduce robustness into the information architecture a priori such that agent loss does not destroy desirable properties. We model the information architecture as a graph G(V, E), where V is a set of vertices representing the agents and E is a set of edges representing information flow amongst the agents. We focus on two properties of the graph called rigidity and global rigidity, which are required for formation shape maintenance and sensor network self-localization, respectively. For the self-repair approach, we show that while previous results permit local repair involving only neighbours of the lost agent, the repair cannot always be implemented using only local information. We present new results that can be applied to make the local repair using only local information. We describe implementation and illustrate with algorithms and examples. For the robustness approach, we investigate the structure of graphs with the property that rigidity or global rigidity is preserved after removing any single vertex (we call the property as 2-vertex-rigidity or 2-vertex-global-rigidity, respectively). Information architectures with such properties would allow formation shape maintenance or self-localization to be performed even in the event of agent failure. We review a characterization of a class of 2-vertex-rigidity and develop a separate class, making significant strides towards a complete characterization. We also present a characterization of a class of 2-vertex-global-rigidity. Copyright © 2008 John Wiley & Sons, Ltd. [source] Observer-based stabilization of linear switching systemsINTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL, Issue 14 2009Paolo Caravani Abstract The discrete component of the hybrid state of a discrete-time linear switching system is assumed to be uncontrolled and unobserved. Conditions of stabilizability for this class of systems are given in terms of a new definition of control invariance, based on the realization of a discrete observer that permits reconstruction of the discrete-state in certain intervals of the time basis. This paper highlights the relationship between the minimum dwell time of the system and its stabilizability. An almost complete characterization of stabilizability is offered in terms of certain subsets of the continuous-state space. These sets are amenable to tractable parametric procedures for controller synthesis. Copyright © 2008 John Wiley & Sons, Ltd. [source] Structure of nanoporous zirconia-based powders synthesized by different gel-combustion routesJOURNAL OF APPLIED CRYSTALLOGRAPHY, Issue 2007Jorge R. Casanova Zirconia-based ceramics that retain their metastable tetragonal phase at room temperature are widely studied due to their excellent mechanical and electrical properties. When these materials are prepared from precursor nanopowders with high specific surface areas, this phase is retained in dense ceramic bodies. In this work, we present a morphological study of nanocrystalline ZrO2,2.8 mol% Y2O3 powders synthesized by the gel-combustion method, using different organic fuels , alanine, glycine, lysine and citric acid , and calcined at temperatures ranging from 873 to 1173,K. The nanopore structures were investigated by small-angle X-ray scattering. The experimental results indicate that nanopores in samples prepared with alanine, glycine and lysine have an essentially single-mode volume distribution for calcination temperatures up to 1073,K, while those calcined at 1173,K exhibit a more complex and wider volume distribution. The volume-weighted average of the nanopore radii monotonically increases with increasing calcination temperature. The samples prepared with citric acid exhibit a size distribution much wider than the others. The Brunauer,Emmett,Teller technique was used to determine specific surface area and X-ray diffraction, environmental scanning electron microscopy and transmission electron microscopy were also employed for a complete characterization of the samples. [source] Graph classes characterized both by forbidden subgraphs and degree sequencesJOURNAL OF GRAPH THEORY, Issue 2 2008Michael D. Barrus Abstract Given a set of graphs, a graph G is -free if G does not contain any member of as an induced subgraph. We say that is a degree-sequence-forcing set if, for each graph G in the class of -free graphs, every realization of the degree sequence of G is also in . We give a complete characterization of the degree-sequence-forcing sets when has cardinality at most two. © 2007 Wiley Periodicals, Inc. J Graph Theory 57: 131,148, 2008 [source] 145 Preliminary Results of Cytoskeletal Components in Various Red Algae Using Confocal Laser Scanning MicroscopyJOURNAL OF PHYCOLOGY, Issue 2003W. E. Schmidt Data concerning the cytoskeletal components of red algae are scant. The goal of this ongoing comparative survey is to develop a more complete characterization of the red algal cytoskeleton, and subsequent elucidation of its function, using representative taxa belonging to major evolutionary lineages within the Rhodophyta. Preliminary data were obtained using enzyme digestion of cell walls and detergent rinses with direct (phalloidin) and indirect (monoclonal antibodies) labeling methods for microfilaments and tubulin, respectively. Samples were viewed using confocal laser scanning microscopy. Results will be discussed in light of the more thoroughly understood cytoskeletal system reported for green algae. [source] The Language of Intoxication: Preliminary InvestigationsALCOHOLISM, Issue 3 2009Ash Levitt Background:, The extensive vocabulary individuals use to describe alcohol's subjective effects has largely gone unexamined in contemporary alcohol research. The present study examined the language drinkers use to describe their own intoxication. It is argued that this language can provide a more complete characterization of alcohol's subjective effects than is available from existing objective and subjective measures of alcohol use and can inform future self-report research. Method:, Toward this goal, a preliminary, cross-sectional, web-based study of the familiarity and usage of current intoxication-related words was conducted in 2 different samples (n = 290 and 146, respectively) of university undergraduates. Results:, Exploratory factor analyses using data from the first sample and confirmatory factor analyses using data from the second sample similarly showed that commonly used terms loaded onto 2 factors, which directly reflected the number of drinks required to be considered moderately or heavily intoxicated, respectively. Gender differences were also found in the familiarity and self-use of some terms across both samples. Conclusions:, The findings suggest that alcohol researchers include multiple intoxication-related terms in future self-report research, and to periodically assess current intoxication-related vocabulary considering demographic, generational, and socio-cultural differences. [source] CONSISTENT MARKET EXTENSIONS UNDER THE BENCHMARK APPROACHMATHEMATICAL FINANCE, Issue 1 2009Damir Filipovi The existence of the growth optimal portfolio (GOP), also known as the Kelly portfolio, is vital for a financial market to be meaningful. The GOP, if it exists, is uniquely determined by the market parameters of the primary security accounts. However, markets may develop and new security accounts become tradable. What happens to the GOP if the original market is extended? In this paper we provide a complete characterization of market extensions which are consistent with the existence of a GOP. We show that a three fund separation theorem applies for the extended GOP. This includes, in particular, the introduction of a locally risk free security, the savings account. We give necessary and sufficient conditions for a consistent exogenous specification of the prevailing short rates. [source] A comprehensive study and modeling of centre-tap differentially driven single-turn integrated inductors for 10-GHz applicationsMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 3 2003S. F. Lim Abstract This paper presents a complete characterization of single-turn differentially driven high-quality (Q) factor inductors at 10 GHz. The separate characterization of individual physical dimension through a series of 3D electromagnetic (EM) simulations allows us to evaluate their effects on the inductor's Q and inductance L separately. The results show that single-turn inductors can generate Q greater than 20 at 10 GHz with inductance L at the sub-nano Henry range. Finally, a lumped-element equivalent circuit of the inductor was developed for predicting associated Q, L, and frequency behavior. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 38: 182,185, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11008 [source] The distant activity of Short Period Comets,, II.MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 1 2008E. Mazzotta Epifani ABSTRACT The activity of the Short Period Comets (SPCs) at large heliocentric distance (Rh > 3 au) occurs in a region of the Solar system where the water sublimation rate is low and so the sublimation of other volatiles, for example CO or CO2, could drive the presence of a coma. The detection of distant activity in a SPC can therefore give important hints on its composition. Moreover, a complete characterization of the distant SPCs degree of activity is crucial in order to give correct estimates of the nucleus size and to obtain more reliable size-distribution curves of cometary nuclei. The aim of this paper is to present the last results of a program of CCD imaging of distant SPCs, started in 2004 December and concluded with observing runs at the 3.5-m Telescopio Nazionale Galileo at La Palma, in 2005 April, and at the 2.2-m Centro Astronómico Hispano Alemán (CAHA) telescope in Spain, in 2005 May. During the Spring 2005 campaign, 12 SPCs have been targeted in the R band (eight numbered SPCs and four still unnumbered SPCs): 61P/Schajn,Schaldach, 71P/Clark, 98P/Takamizawa, 103P/Hartley 2, 117P/Helin,Roman,Alu 1, 118P/Shoemaker,Levy 4, 121P/Shoemaker,Holt 2, 136P/Mueller 3, P/2002 T5 (LINEAR), P/2003 S1 (NEAT), P/2003 S2 (NEAT), P/2004 DO29 (Spacewatch,LINEAR). The heliocentric distance of the targets was 3.05 ,Rh, 5.30 au. Several levels of activity were detected in the sample, from stellar appearance to well-developed coma and tail. In some cases, the occurrence of cometary activity could be enhanced only with deep visible imaging (e.g. with very long exposure time). For comets with stellar appearance, it was possible to derive a value or a range for the nucleus radius rnucleus (assuming a ,classical' albedo value of 0.04): 98P (rnucleus= 0.43 ± 0.10 km), 136P (rnucleus= 1.2 ± 0.2 km), P/2003 S2 (rnucleus= 0.81 to 1.55 km). For the active comets, we measured dust production levels in terms of Af, quantity, which was 9.9 , Af,, 671 cm. Ensemble properties of the whole sample of the long-term program (a total of 17 SPCs) have been analysed in terms of the relationship among distant activity and dynamical evolution of the targets (in particular, an inward ,jump' of the perihelion distance): we can conclude that, even if there is some theoretical indication that this could occur, the hypothesis of distant activity triggered by a rise in perihelion temperature cannot be univocally invoked for these comets. [source] Organic anion transporters: discovery, pharmacology, regulation and roles in pathophysiologyBIOPHARMACEUTICS AND DRUG DISPOSITION, Issue 1 2010Adam L. VanWert Abstract Our understanding of the mechanisms behind inter- and intra-patient variability in drug response is inadequate. Advances in the cytochrome P450 drug metabolizing enzyme field have been remarkable, but those in the drug transporter field have trailed behind. Currently, however, interest in carrier-mediated disposition of pharmacotherapeutics is on a substantial uprise. This is exemplified by the 2006 FDA guidance statement directed to the pharmaceutical industry. The guidance recommended that industry ascertain whether novel drug entities interact with transporters. This suggestion likely stems from the observation that several novel cloned transporters contribute significantly to the disposition of various approved drugs. Many drugs bear anionic functional groups, and thus interact with organic anion transporters (OATs). Collectively, these transporters are nearly ubiquitously expressed in barrier epithelia. Moreover, several reports indicate that OATs are subject to diverse forms of regulation, much like drug metabolizing enzymes and receptors. Thus, critical to furthering our understanding of patient- and condition-specific responses to pharmacotherapy is the complete characterization of OAT interactions with drugs and regulatory factors. This review provides the reader with a comprehensive account of the function and substrate profile of cloned OATs. In addition, a major focus of this review is on the regulation of OATs including the impact of transcriptional and epigenetic factors, phosphorylation, hormones and gender. Copyright © 2009 John Wiley & Sons, Ltd. [source] | |||||||||||||||||||||||||