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Constant
Kinds of Constant Terms modified by Constant Selected AbstractsPRINCIPLES OF POLITICS APPLICABLE TO ALL GOVERNMENTS BY BENJAMIN CONSTANT,ECONOMIC AFFAIRS, Issue 3 2004Dennis O'Keeffe In this review of Constant's Principles of Politics Applicable to All Governments, Constant's belief in liberal economics and the importance of tradition is analysed. [source] Polarizability, Susceptibility, and Dielectric Constant of Nanometer-Scale Molecular Films: A Microscopic ViewADVANCED FUNCTIONAL MATERIALS, Issue 13 2010Amir Natan Abstract The size-dependence of the polarizability, susceptibility, and dielectric constant of nanometer-scale molecular layers is explored theoretically. First-principles calculations based on density functional theory are compared to phenomenological modeling based on polarizable dipolar arrays for a model system of organized monolayers composed of oligophenyl chains. Size trends for all three quantities are primarily governed by a competition between out-of-plane polarization enhancement and in-plane polarization suppression. Molecular packing density is the single most important factor controlling this competition and it strongly affects the bulk limit of the dielectric constant as well as the rate at which it is approached. Finally, the polarization does not reach its "bulk" limit, as determined from the Clausius,Mossotti model, but the susceptibility and dielectric constant do converge to the correct bulk limit. However, whereas the Clausius,Mossotti model describes the dielectric constant well at low lateral densities, finite size effects of the monomer units cause it to be increasingly inaccurate at high lateral densities. [source] FELLOW CITIZENS AND IMPERIAL SUBJECTS: CONQUEST AND SOVEREIGNTY IN EUROPE'S OVERSEAS EMPIRESHISTORY AND THEORY, Issue 4 2005ANTHONY PAGDEN ABSTRACT This article traces the association between the European overseas empires and the concept of sovereignty, arguing that, ever since the days of Cicero,if not earlier,Europeans had clung to the idea that there was a close association between a people and the territory it happened to occupy. This made it necessary to think of an "empire" as a unity,an "immense body," to use Tacitus's phrase,that would embrace all its subjects under a single sovereign. By the end of the eighteenth century it had become possible, in this way, to speak of "empires of liberty" that would operate for the ultimate benefit of all their "citizens," freeing them from previous tyrannical rulers and bringing them under the protection of more benign regimes. In such empires sovereignty could only ever be, as it had become in Europe, undivided. The collapse of Europe's "first" empires in the Americas, however, was followed rapidly by Napoleon's attempt to create a new kind of Empire in Europe. The ultimate, and costly, failure of this project led many, Benjamin Constant among them, to believe that the age of empires was now over and had been replaced by the age of commerce. But what in fact succeeded Napoleon was the modern European state system, which attempted not to replace empire by trade, as Constant had hoped, but to create a new kind of empire, one that sought to minimize domination and settlement, and to make a sharp distinction between imperial ruler and imperial subject. In this kind of empire, sovereignty could only be "divided." Various kinds of divided rule were thus devised in the nineteenth century. Far, however, from being an improvement on the past, this ultimately resulted in,or at least contributed greatly to,the emergence of the largely fictional and inevitably unstable societies that after the final collapse of the European empires became the new states of the "developing world." [source] Creole Materialities: Archaeological Explorations of Hybridized Realities on a North American PlantationJOURNAL OF HISTORICAL SOCIOLOGY, Issue 1 2010STEPHEN A. MROZOWSKI This paper explores the hybridized realities of European, Native American and Afro-Caribbean/Afro-American residents of Sylvester Manor, New York and Constant Plantation, Barbados during the seventeenth century. It draws on archaeological and landscape evidence from two plantations that were owned and operated by different members of the same family during the seventeenth century. One of plantations, known as Sylvester Manor, encompassed all 8,000 acres of Shelter Island, New York. It was established in 1652 primarily to help in the provisioning of two large sugar plantations on Barbados, Constant and Carmichael plantations. Sylvester Manor was operated by Nathaniel Sylvester; an Englishman who spent the first twenty years of life living in Amsterdam where his father was a merchant. Constant and Carmichael plantations were operated by his brother Constant Sylvester. Both the Barbados and New York plantations relied upon a labor force of enslaved Afro-Caribbean's. Archaeological evidence from Sylvester Manor has also revealed that Native American laborers played a prominent role in the daily activities of this northern plantation. Material and landscape evidence reveal the construction of hybridized identities that in the case of Barbados, are still part of the fabric of a postcolonial reality. Evidence from Sylvester Manor provides detailed insights into the construction of hybridized identities under the exigencies of a plantation economy whose global connections are dramatically visible in the archaeological record. [source] Constant or special observations of inpatients presenting a risk of aggression or violence: nurses' perceptions of the rules of engagementJOURNAL OF PSYCHIATRIC & MENTAL HEALTH NURSING, Issue 4 2005I. MACKAY bsc (hons) rmn In acute psychiatric settings the practice of ,observation' is commonly employed. Increased levels of observation, ,constant' or ,special' are used for those perceived as presenting a ,higher' risk. As an intervention it is used most frequently for those at risk of self-harm or suicide, the practice is also however, used for those thought to present a risk of violent behaviour. In this descriptive study the perceptions of 1st level registered mental nurses (RMNs) gave an account of observation for those perceived to be at risk of violence or aggression and insight into what was considered important and desirable in practice. Unstructured qualitative interviews were conducted with a purposive sample of six RMNs from a psychiatric intensive care unit. Three major categories, Procedure, Role, and Skills emerged which revealed a complex practice far removed from its literal description as merely ,watching'. Six subcategories emerged from the Role. (1) intervening; (2) maintaining the safety of the patient and others; (3) prevention de-escalation and the management of aggression and violence; (4) assessing; (5) communication; and (6) therapy. Skills in these and, experience were thought to IMPACT on the success of the practice. The description of this and the skills involved offer a definition of the ,rules of engagement' which give insight to the practice and the training needs of staff advocated for ,observation'. The acronym IMPACT may be useful in this. [source] Contextualising Recent Tensions in Seventh-day Adventism: "A Constant Process of Struggle and Rebirth"?JOURNAL OF RELIGIOUS HISTORY, Issue 3 2010ARTHUR PATRICK Between 1844 and 1863, fragments of disappointed Millerism developed the landmark ideas, the denominational name and the basic structure of what is now the Seventh-day Adventist Church with fifteen million members (2008) in 201 countries. This article contextualises the struggle of recent decades between continuity and change in Adventist teaching, suggesting that a score of doctoral theses/dissertations and other studies offer a coherence that is deeply disturbing for some believers, insufficient for some others, but satisfying for many. The demands in Western culture for faith to be shaped by evidence and to offer existential meaning have elicited three stances in relation to traditional Adventist thought: reversion, alienation, and transformation. Whereas the consequent tensions may be viewed as evidence of "growth, vitality and increased understanding," they also constitute an urgent call for effective internal and external dialogue. [source] Enhanced Permeability and Dielectric Constant of NiZn Ferrite Synthesized in Nanocrystalline Form by a Combustion MethodJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 5 2007Sasanka Deka The performance parameters of Ni0.5Zn0.5Fe2O4, synthesized in the nanocrystalline form by an autocombustion method, have been investigated. The sample sintered at 1200°C, with Bi2O3 as additive shows a very high value of initial permeability ,,i of >400 at 1 MHz, with low loss. Similarly, a very high dielectric constant is obtained at lower frequencies. The results show that optimum magnetic and electrical properties can be achieved for the NiZn ferrite nanocrystalline powders synthesized by the present autocombustion method and sintered at a relatively lower temperature of 1200°C when compared with a temperature of 1400°C required for the materials synthesized by the conventional ceramic method. [source] Mirror Constant for Tyranno® Silicon-Titanium-Carbon-Oxygen Fibers Measured in Situ in a Three-Dimensional Woven Silicon Carbide/Silicon Carbide CompositeJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 3 2002Ian J. Davies The strength, S, of ceramic and glass fibers often can be estimated from fractographic investigation using the fracture mirror radius, rm, and the relationship S=Am/(rm)1/2, where Amis the "mirror constant." The present work estimates the value of Amfor Tyranno® Si-Ti-C-O fibers in situ in a three-dimensional woven SiC/SiC-based composite to be 2.50 ± 0.09 MPa·m1/2. This value is within the range of 2,2.51 MPa·m1/2 previously obtained for nominally similar Nicalon® Si-C-O fibers. [source] From First Design Brainstorm Session to Final Coat of Paint: Communication, an Essential ConstantNEW DIRECTIONS FOR STUDENT SERVICES, Issue 101 2003Jerry Price Hundreds of variables must be considered when undertaking even the smallest construction project. When renovating a still-occupied seven-hundred-bed residence complex, however, the details to manage seem endless. Effective communication among all parties,especially students,is essential to completing the project successfully. [source] Liberal Values: Benjamin Constant and the Politics of Religion , By Helena RosenblattRELIGIOUS STUDIES REVIEW, Issue 2 2010Andrew Dole No abstract is available for this article. [source] Effects of Constant, 9 and 16-h Light Cycles on Sperm Quality, Semen Storage Ability and Motile Sperm Subpopulations Structure of Boar SemenREPRODUCTION IN DOMESTIC ANIMALS, Issue 5 2006MM Rivera Contents This study was performed to test the effect that two separate, daily, constant-light regimes of both 9 and 16 h could have on the main parameters of boar-semen quality analysis, as well as on the motile sperm subpopulations structure and the ability of its conservation at 16°C. Results show that both luminous regimes have slight, specific effects on the main parameters of boar-semen quality analysis, as well as on the motile sperm subpopulations structure. Furthermore, the conservation ability at 16°C of boar semen was not significantly different between both photoperiods. When a temporal study was performed, results showed that semen quality and motility parameter changes were stabilized at nearly constant values from the second month of the study to the last month in both luminous regimes, indicating a rapid light-related effect on testicular function. Our results indicate that light regimes oscillating from 9 h daily to 16 h daily are of little importance in the control of boar-semen quality in a farming environment. [source] ChemInform Abstract: New Percolative BaTiO3,Ni Composites with a High and Frequency-Independent Dielectric Constant (,r , 80000).CHEMINFORM, Issue 51 2001Carlos Pecharroman Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] Estimation of Ion-Pairing Constants in Plasticized Poly(vinyl chloride) Membranes Using Segmented Sandwich Membranes TechniqueELECTROANALYSIS, Issue 17-18 2009Vladimir Abstract Segmented sandwich membrane method was used to determine ion-pairing constants for four cationic sites: tris-(2,3,4-dodecyloxy)benzenetrimethylammonium, tris-(2,3,4-dodecyloxy)benzenedimethyloctylammonium, tris-(2,3,4-dodecyloxy)benzenemethyldioctylammonium, and dimethyldioctadecylammonium with chloride, bromide, nitrate, benzene sulfonate, trichloroacetate, thiocyanate, perchlorate and picrate, as well as ion-pairing constants for two anionic sites: tetraphenylborate and tris-(2,3,4-octyloxy)benzenesulfonate with dimedrol, quinine, anapriline, and amantadine cations in poly(vinyl chloride) membranes plasticized with 2-nitrophenyl octyl ether. Ion association constants of anions with quaternary ammonium sites regularly increase from picrate to chloride along with reduction of the anion radius and with improvement of site exchanger center steric accessibility. Ion association constants of amine cations with tris-(2,3,4-octyloxy)benzenesulfonate are several orders higher than those with tetraphenylborate and regularly increase from tertiary amine to primary one. [source] Voltammetry as a Virtual Potentiometric Sensor in Modeling of a Metal-Ligand System and Refinement of Stability Constants.ELECTROANALYSIS, Issue 8 2004Part 1. Abstract A mathematical conversion of data coming from nonequilibrium and dynamic voltammetric techniques (a direct current sampled (DC) and differential pulse (DP) polarography) into potentiometric sensor type of data is described and tested on a dynamic metal-ligand system. A combined experiment involving DCP, DPP and glass electrode potentiometry (GEP) was performed on a single solution sample containing a fixed [LT],:,[MT] ratio (acid-base titration). Dedicated potentiometric software ESTA was successfully employed in the refinement operations performed on virtual potentiometric (VP) data obtained from DC and DP polarography. It was possible to refine stability constants either separately, from VP-DC or VP-DP, or simultaneously from any combination of VP-DC, VP-DP and GEP. The concept of VP-DC or VP-DP is reported for the first time and numerous documented and possible advantages are discussed. The proposed procedure can be easily utilized also by nonelectrochemists who are interested in, e.g., the ligand design strategies. [source] Stability Constants and Dissociation Rates of the EDTMP Complexes of Samarium(III) and Yttrium(III)EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 30 2008Ferenc Krisztián Kálmán Abstract The stability constants of Sm(EDTMP) (log,KML = 20.71) and Y(EDTMP) (log,KML = 19.19) were determined by a competition reaction between the Ln3+ ion (Ln3+ = Sm3+ or Y3+) and Cu2+ for the EDTMP ligand by spectrophotometry at pH , 10, in the presence of an excess amount of citrate (0.15 M NaCl, 25 °C). For determining the stability constants of Cu(EDTMP) (log,KML = 19.36) and Ca(EDTMP) (log,KML = 8.71) pH,potentiometry was used. In the pH range 4,9 the EDTMP complexes are present in the form of nonprotonated and mono-, di- and triprotonated species. The Ca2+ ion forms a dinuclear complex with Ln(EDTMP). In a simplified blood plasma model consisting of Sm3+, Ca2+ and Zn2+ metal ions, EDTMP, citrate, cysteine and histidine ligands, Sm3+ is practically present in the form of [Sm(HEDTMP)Ca]2,, whereas Zn2+ predominantly forms [Zn(HEDTMP)]5, and [Zn(H2EDTMP)]4, complexes. For studying the dissociation rates of the complexes, the kinetics of the metal exchange (transmetallation) reactions between the Ln(EDTMP) complexes and Cu2+,citrate were investigated in the pH range 7,9 by the stopped-flow method. The rates of the exchange reactions are independent of the Cu2+ concentration and increase with the H+ concentration. The rate constants, characterizing the proton-assisted dissociation of the Ln(EDTMP) complexes, are several orders of magnitude higher than those of the similar Ln(EDTA) complexes, because the protonation constants of Ln(EDTMP) are high and the protonated Ln(HEDTMP) and Ln(H2EDTMP) species are present in higher concentration. The half-times of dissociation of Sm(EDTMP) and Y(EDTMP) at pH = 7.4 and 25 °C are 4.9 and 7.5 s, respectively. These relatively short dissociation half-time values do not predict the deposition of Ln3+ ions in bones in the form of intact Ln(EDTMP) complexes. It is more probable that sorption of the EDTMP ligand and Sm3+ or Y3+ ions occurs independently after the dissociation of complexes.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) [source] Optimised Dirac operators on the lattice: construction, properties and applicationsFORTSCHRITTE DER PHYSIK/PROGRESS OF PHYSICS, Issue 2 20082Article first published online: 29 NOV 200, W. Bietenholz Abstract We review a number of topics related to block variable renormalisation group transformations of quantum fields on the lattice, and to the emerging perfect lattice actions. We first illustrate this procedure by considering scalar fields. Then we proceed to lattice fermions, where we discuss perfect actions for free fields, for the Gross-Neveu model and for a supersymmetric spin model. We also consider the extension to perfect lattice perturbation theory, in particular regarding the axial anomaly and the quark gluon vertex function. Next we deal with properties and applications of truncated perfect fermions, and their chiral correction by means of the overlap formula. This yields a formulation of lattice fermions, which combines exact chiral symmetry with an optimisation of further essential properties. We summarise simulation results for these so-called overlap-hypercube fermions in the two-flavour Schwinger model and in quenched QCD. In the latter framework we establish a link to Chiral Perturbation Theory, both, in the p -regime and in the ,-regime. In particular we present an evaluation of the leading Low Energy Constants of the chiral Lagrangian , the chiral condensate and the pion decay constant , from QCD simulations with extremely light quarks. [source] The Tris(trimethylsilyl)silane/Thiol Reducing System: A Tool for Measuring Rate Constants for Reactions of Carbon-Centered Radicals with ThiolsHELVETICA CHIMICA ACTA, Issue 10 2006Chryssostomos Chatgilialoglu Abstract An extension of the well-known ,free-radical-clock' methodology is described that allows one to determine the rate constants of carbon-centered radicals with a variety of thiols by using the tris(trimethylsilyl)silane/thiol couple as a reducing system. A total of 20 rate constants for the hydrogen abstraction from a variety of alkyl-, silyl-, and aryl-substituted thiols by the primary-alkyl radical 2 in toluene at 80° were determined with the aid of the 5- exo-trig cyclization as a timing device. Further, seven rate constants for the hydrogen abstraction from a variety of alkyl- and silyl-substituted thiols by the acyl radical 9 in benzene at 80° were measured using the decarbonylation process as a timing device. The rate constants varied over two orders of magnitude from 106 to 108,M,1 s,1. Substituent effects were rationalized. The radical-trapping abilities of these reducing systems and those of other common hydrogen donors were compared. [source] Theoretical study of ribonucleotide reductase mechanism-based inhibition by 2,-azido-2,-deoxyribonucleoside 5,-diphosphatesJOURNAL OF COMPUTATIONAL CHEMISTRY, Issue 2 2004Susana Pereira Abstract 2,-Azido-2,-deoxyribonucleoside 5,-diphosphates are mechanism-based inhibitors of Ribonucleotide Reductase. Considerable effort has been made to elucidate their mechanism of inhibition, which is still controversial and not fully understood. Previous studies have detected the formation of a radical intermediate when the inhibitors interact with the enzyme, and several authors have proposed possible structures for this radical. We have conducted a theoretical study of the possible reactions involved, which allowed us to identify the structure of the new radical among the several proposals. A new reactional path is also proposed that is the most kinetically favored to yield this radical and ultimately inactivate the enzyme. The energetic involved in this mechanism, both for radical formation and radical decay, as well as the calculated Hyperfine Coupling Constants for the radical intermediate, are in agreement with the correspondent experimental values. This mechanistic alternative is fully coherent with remaining experimental data. © 2003 Wiley Periodicals, Inc. J Comput Chem 25: 227,237, 2004 [source] THE ANALYSIS OF STRESS RELAXATION DATA OF SOME VISCOELASTIC FOODS USING A TEXTURE ANALYZER,JOURNAL OF TEXTURE STUDIES, Issue 4 2006H. SINGH ABSTRACT Uniaxial compression test for dough and several commercial products like jello, mozzarella cheese, cheddar cheese, tofu and sausage (cooked and uncooked) was performed using a texture analyzer (TA). Percent stress relaxation (%SR ), k1 (initial rate of relaxation), k2 (extent of relaxation) and relaxation time (RT) were calculated and compared for different products. The TA software was used to convert the raw SR data into a linear form. Constants k1 and k2 were determined from the intercept and slope of the linear data. Higher values of %SR and k2 (90 and 9, respectively) indicated higher elasticity for jello, whereas wheat flour dough samples showed the lowest values (20,30) for %SR and 1 to 2 for k2. The RT and k1 values were not good indicators for differentiating different products based on their viscoelastic behavior. Measurement of RT was limited by the maximum time for which the data were collected, whereas k1, because of its mathematical form, needed careful interpretation. In this study, %SR was found to be a good measure to interpret viscoelasticity of different food samples. [source] Origins and Applications of London Dispersion Forces and Hamaker Constants in CeramicsJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 9 2000Roger H. French The London dispersion forces, along with the Debye and Keesom forces, constitute the long-range van der Waals forces. London's and Hamaker's work on the point-to-point dispersion interaction and Lifshitz's development of the continuum theory of dispersion are the foundations of our understanding of dispersion forces. Dispersion forces are present for all materials and are intrinsically related to the optical properties and the underlying interband electronic structures of materials. The force law scaling constant of the dispersion force, known as the Hamaker constant, can be determined from spectral or parametric optical properties of materials, combined with knowledge of the configuration of the materials. With recent access to new experimental and ab initio tools for determination of optical properties of materials, dispersion force research has new opportunities for detailed studies. Opportunities include development of improved index approximations and parametric representations of the optical properties for estimation of Hamaker constants. Expanded databases of London dispersion spectra of materials will permit accurate estimation of both nonretarded and retarded dispersion forces in complex configurations. Development of solutions for generalized multilayer configurations of materials are needed for the treatment of more-complex problems, such as graded interfaces. Dispersion forces can play a critical role in materials applications. Typically, they are a component with other forces in a force balance, and it is this balance that dictates the resulting behavior. The ubiquitous nature of the London dispersion forces makes them a factor in a wide spectrum of problems; they have been in evidence since the pioneering work of Young and Laplace on wetting, contact angles, and surface energies. Additional applications include the interparticle forces that can be measured by direct techniques, such as atomic force microscopy. London dispersion forces are important in both adhesion and in sintering, where the detailed shape at the crack tip and at the sintering neck can be controlled by the dispersion forces. Dispersion forces have an important role in the properties of numerous ceramics that contain intergranular films, and here the opportunity exists for the development of an integrated understanding of intergranular films that encompasses dispersion forces, segregation, multilayer adsorption, and structure. The intrinsic length scale at which there is a transition from the continuum perspective (dispersion forces) to the atomistic perspective (encompassing interatomic bonds) is critical in many materials problems, and the relationship of dispersion forces and intergranular films may represent an important opportunity to probe this topic. The London dispersion force is retarded at large separations, where the transit time of the electromagnetic interaction must be considered explicitly. Novel phenomena, such as equilibrium surficial films and bimodal wetting/dewetting, can result in materials systems when the characteristic wavelengths of the interatomic bonds and the physical interlayer thicknesses lead to a change in the sign of the dispersion force. Use of these novel phenomena in future materials applications provides interesting opportunities in materials design. [source] Quantitative Analysis of Dielectric Constants from EFM Images of Multicomponent Polymer BlendsMACROMOLECULAR CHEMISTRY AND PHYSICS, Issue 11 2006Andrey V. Krayev Abstract Summary: A simple quantitative model for the analysis of EFM images of three- or more-component polymer blends is applied to determine the dielectric constants of the blend constituents. The value of the dielectric constant of PIPA calculated from the EFM images of POMA-PIPA-APP blend is determined in good agreement with the literature value. [source] Estimation of Aqueous-Phase Reaction Rate Constants of Hydroxyl Radical with Phenols, Alkanes and AlcoholsMOLECULAR INFORMATICS, Issue 11-12 2009Ya-nan Wang Abstract A quantitative structure activity relationship (QSAR) model was developed for the aqueous-phase hydroxyl radical reaction rate constants (kOH) employing quantum chemical descriptors and multiple linear regressions (MLR). The QSAR development followed the OECD guidelines, with special attention to validation, applicability domain (AD) and mechanistic interpretation. The established model yielded satisfactory performance: the correlation coefficient square (R2) was 0.905, the root mean squared error (RMSE) was 0.139, the leave-many-out cross-validated QLMO2 was 0.806, and the external validated QEXT2 was 0.922 log units. The AD of the model covering compounds of phenols, alkanes and alcohols, was analyzed by Williams plot. The main molecular structural factors governing kOH are the energy of the highest occupied molecular orbital (EHOMO), average net atomic charges on hydrogen atoms (), molecular surface area (MSA) and dipole moment (,). It was concluded that kOH increased with increasing EHOMO and MSA, while decreased with increasing and ,. [source] Estimation of Carboxylic Acid Ester Hydrolysis Rate ConstantsMOLECULAR INFORMATICS, Issue 9-10 2003H. Hilal Abstract SPARC chemical reactivity models were extended to calculate hydrolysis rate constants for carboxylic acid esters from molecular structure. The energy differences between the initial state and the transition state for a molecule of interest are factored into internal and external mechanistic perturbation components. The internal perturbations quantify the interactions of the appended perturber (P) with the reaction center (C). These internal perturbations are factored into SPARC's mechanistic components of electrostatic and resonance effects. External perturbations quantify the solute-solvent interactions and are factored into H-bonding, field stabilization and steric effects. These models have been tested using 1471 measured hydrolysis rate constants in water and mixed-solvent systems at different temperatures. The aggregate RMS deviation of the calculated versus observed values was 0.374,M,1s,1; close to the intralaboratory experimental error. [source] Rotational Spectra, Structures, Hyperfine Constants, and the Nature of the Bonding of KrCuF and KrCuCl.CHEMINFORM, Issue 34 2004Julie M. Michaud No abstract is available for this article. [source] A Theoretical Study of the NMR Spin,Spin Coupling Constants of the Complexes [(NC)5Pt,Tl(CN)n]n- (n = 0,3) and [(NC)5Pt,Tl,Pt(CN)5]3- : A Lesson on Environmental Effects.CHEMINFORM, Issue 2 2004Jochen Autschbach No abstract is available for this article. [source] Atomistic Simulation of the Lattice Constants and Lattice Vibrations in LnM4Al8 (Ln: Nd, Sm; M: Cr, Mn, Cu, Fe).CHEMINFORM, Issue 39 2003Yan-mei Kang No abstract is available for this article. [source] Isotropic 13C Hyperfine Coupling Constants Distinguish Neutral from Anionic Ubiquinone-Derived Radicals,CHEMPHYSCHEM, Issue 18 2009Scott E. Boesch A radical notion: Calculated isotropic 13C hyperfine coupling constants are distinctly different for the anionic ubisemiquinone model UQ., (picture, left) rather than the protonated UQH. (picture, right) and can distinguish between the two in electron transfer proteins such as cytochrome bo3, cytochrome bc1, or photosynthetic reaction centers. [source] Evaluation of Intrinsic Ionization and Complexation Constants of TiO2 and Mg-Fe Hydrotalcite-like CompoundsCHINESE JOURNAL OF CHEMISTRY, Issue 10 2006Wan-Guo Hou Abstract The intrinsic surface reaction constants, pKinta1, pKinta2, p*KintC and p*KintA, were evaluated by a modified double extrapolation (MDE) for TiO2 without structural charge and Mg-Fe hydrotalcite-like compounds (HTlc) with structural charge, respectively. The results of intrinsic surface reaction constants for TiO2 were compared with those obtained by class double extrapolation (CDE) in literature. Furthermore, the values of intrinsic surface reaction constants obtained by MDE were used to simulate the charging behaviors of the materials. The following conclusions were obtained. For TiO2 without structural charge, the pKinta1 and pKinta2 evaluated by MDE are equal to those by CDE, however the p*KintC and p*KintA evaluated by MDE are much different from those by CDE. In principle, the results of the p*KintC and p*KintA evaluated by MDE are more accurate than those by CDE. The values of intrinsic surface reaction constants obtained by MDE can excellently simulate the charging curves for TiO2 with the triple layer model (TLM). For HTlc with positive structural charge, the results of *KintC=0 and *KintA,, were obtained by MDE, which means the inert electrolyte chemical binding does not exist; the point of zero net charge (PZNC) of c -independence also exist as the same as solid without structural charge, and the pHPZNC obtained by the acid-base titration can excellently be simulated and the surface charging tendency can be simulated to a great extent using the pKinta1 and pKinta2 evaluated by MDE and the diffuse layer model (DLM). [source] Sensitivity-enhanced Experiments for the Measurement of J and Dipolar Coupling ConstantsCHINESE JOURNAL OF CHEMISTRY, Issue 7 2002Dong-Hai Lin Abstract A sensitivity-enhanced IPAP NMR experiment was described in this paper, which separates the 1H- 15N doublets into two different spectra to alleviate the problem of resonance overlaps and achieve the accurate measurement of J and residual dipolar coupling constants in proteins. This experiment offered 20%,60% sensitivity enhancement over the original IPAP experiment, and therefore produced more measurable resonances. Pulsed field gradient was used for coherence selection. Water-flip-back approach was used for water suppression. The sensitivity-enhanced IPAP experiment was employed in the measurement of 1JNH and 1DNH constants of the protein UBC9. [source] Irradiance Gradients in the Presence of Participating Media and OcclusionsCOMPUTER GRAPHICS FORUM, Issue 4 2008Wojciech Jarosz Abstract In this paper we present a technique for computing translational gradients of indirect surface reflectance in scenes containing participating media and significant occlusions. These gradients describe how the incident radiance field changes with respect to translation on surfaces. Previous techniques for computing gradients ignore the effects of volume scattering and attenuation and assume that radiance is constant along rays connecting surfaces. We present a novel gradient formulation that correctly captures the influence of participating media. Our formulation accurately accounts for changes of occlusion, including the effect of surfaces occluding scattering media. We show how the proposed gradients can be used within an irradiance caching framework to more accurately handle scenes with participating media, providing significant improvements in interpolation quality. [source] | ||||||||||||||||||||||||||||||||||||||||||||||||||||