scholarly journals Spin-ice physics in cadmium cyanide

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Chloe S. Coates ◽  
Mia Baise ◽  
Adrian Schmutzler ◽  
Arkadiy Simonov ◽  
Joshua W. Makepeace ◽  
...  
Keyword(s):  
Dipole Moments ◽  
Interaction Strength ◽  
Magnetic Interaction ◽  
Energy Scale ◽  
Spin Ice ◽  
Structural Behaviour ◽  
Geometric Frustration ◽  
Cadmium Cyanide ◽  
The Difference ◽  
Increased Strength

AbstractSpin-ices are frustrated magnets that support a particularly rich variety of emergent physics. Typically, it is the interplay of magnetic dipole interactions, spin anisotropy, and geometric frustration on the pyrochlore lattice that drives spin-ice formation. The relevant physics occurs at temperatures commensurate with the magnetic interaction strength, which for most systems is 1–5 K. Here, we show that non-magnetic cadmium cyanide, Cd(CN)2, exhibits analogous behaviour to magnetic spin-ices, but does so on a temperature scale that is nearly two orders of magnitude greater. The electric dipole moments of cyanide ions in Cd(CN)2 assume the role of magnetic pseudospins, with the difference in energy scale reflecting the increased strength of electric vs magnetic dipolar interactions. As a result, spin-ice physics influences the structural behaviour of Cd(CN)2 even at room temperature.

Charge-Transfer Dipoles at the Si-SiO2 Interface and the Metal-Semiconductor Worfunction Difference In Mos Devices.

1987 ◽  
Vol 105 ◽  
Author(s):  
Hisham Z. Massoud
Keyword(s):  
Dipole Moment ◽  
Charge Transfer ◽  
Dipole Moments ◽  
Silicon Substrates ◽  
Interface Dipole ◽  
Mos Devices ◽  
Flatband Voltage ◽  
The Difference ◽  
Definition Of ◽  
Mos Structures

AbstractThe magnitude of the dipole moment at the Si-SiO2 interface resulting from partial charge transfer that takes place upon the formation of interface bonds has been calculated. The charge transfer occurs because of the difference in electronegativity between silicon atoms and SiO2 molecules which are present across the interface. Results obtained for (100) and (111) silicon substrates indicate that the magnitude of the interface dipole moment is dependent on substrate orientation and the interface chemistry. Dipole moments at the Si-SiO2 and gate-SiO2 interfaces should be included in the definition of the flatband voltage VFB of MOS structures. CV-based measurements of the metal-semiconductor workfunction difference φms on (100) and (111) silicon oxidized in dry oxygen and metallized with Al agree with the predictions of this model. Other types of interface dipoles and their processing dependence are briefly discussed.

Experimental and computed dipole moments in donor–bridge–acceptor systems with p-phenylene and p-carboranediyl bridges

2009 ◽  
Vol 74 (1) ◽  
pp. 131-146 ◽  
Author(s):  
Ladislav Drož ◽  
Mark A. Fox ◽  
Drahomír Hnyk ◽  
Paul J. Low ◽  
J. A. Hugh MacBride ◽  
...  
Keyword(s):  
Dipole Moment ◽  
Dipole Moments ◽  
Electronic Effects ◽  
Electronic Interactions ◽  
Donor And Acceptor ◽  
Homo And Lumo ◽  
Pull Systems ◽  
The Difference ◽  
Experimental Values ◽  
2D And 3D

Dipole moments were measured for a series of substituted benzenes, biphenyls, terphenyls, C-monoaryl- and C,C′-diaryl-p-carboranes. For the donor–bridge–acceptor systems, Me2N–X–NO2, where X is 1,4-phenylene, biphenyl-4,4′-diyl, terphenyl and 1,4-C6H4-p-CB10H10C-1,4-C6H4, the measured interaction dipole moments are 1.36, 0.74, 0.51 and 0.00 D, respectively. The magnitude of the dipole moment reflects the ability of the bridge to transmit electronic effects between donor and acceptor groups. Thus, whilst the 1,4-phenylene bridges allow moderate electronic interactions between the remote groups, the p-carboranediyl unit is less efficient as a conduit for electronic effects. Averaged dipole moments computed at the DFT (B3LYP/6-31G*) level of theory from two distinct molecular conformers are in good agreement with the experimental values. Examination of the calculated electronic structures provides insight into the nature of the interactions between the donor and acceptor moieties through these 2D and 3D aromatic bridges. The most significant cooperative effect of the bridge on the dipole moment occurs in systems where there is some overlap between the HOMO and LUMO orbitals. This orbital overlap criterion may help to define the difference between “push-pull” systems in which electronic effects are mediated by the bridging moiety, and simpler systems in which the bridge acts as an electronically innocent spacer unit and through-space charge transfer/separation is dominant.

Deformation of Perforated Aluminium Plates under In-Plane Compressive Loading

2016 ◽  
Vol 710 ◽  
pp. 357-362
Author(s):  
Irene Scheperboer ◽  
Evangelos Efthymiou ◽  
Johan Maljaars
Keyword(s):  
Research Work ◽  
Compressive Loading ◽  
Local Buckling ◽  
Buckling Load ◽  
Structural Behaviour ◽  
Critical Buckling Load ◽  
Out Of Plane ◽  
The Difference ◽  
Ultimate Resistance ◽  
Multiple Holes

Aluminium plates containing a single hole or multiple holes in a row are recently becoming very popular among architects and consultant engineers in many constructional applications, due to their reduced weight, as well as facilitating ventilation and light penetration of the buildings. However, there are still uncertainties concerning their structural behaviour, preventing them from wider utilization. In the present paper, local buckling phenomenon of perforated aluminium plates has been studied using the finite element method. For the purposes of the research work, plates with simply supported edges in the out-of-plane direction and subjected to uniaxial compression are examined. In view of perforations, circular cut-outs and the total cut-out size has been varied between 5 and 40% of the total plate area. Moreover, different perforation patterns have been investigated, from a single, central cut-out to a more refined pattern consisting of up to 25 holes equally distributed over the plate. Regarding the material characteristics, several aluminium alloys are considered and compared to steel grade A36 on plates of different slenderness. For each case the critical (Euler) buckling load and the ultimate resistance has been determined.A study into the boundary conditions of the plate showed that the restrictions at the edges parallel to the load direction have a large influence on the critical buckling load. Restraining the top or bottom edge does not significantly influence the resistance of the plate.The results showed that the ultimate resistance of aluminium plates containing multiple holes occurs at considerably larger out-of-plane displacement as that of full plates. For very large total cut-out, a plate containing a central hole has a larger resistance than a plate with equal cut-out percentage but with multiple holes. The strength and deformation in the post-critical regime, i.e. the difference between the critical buckling load and the ultimate resistance, differs significantly for different number of holes and cut-out percentage.

scholarly journals ATXN1 N-terminal region explains the binding differences of wild-type and expanded forms

2019 ◽  
Vol 12 (1) ◽  
Author(s):  
Sara Rocha ◽  
Jorge Vieira ◽  
Noé Vázquez ◽  
Hugo López-Fernández ◽  
Florentino Fdez-Riverola ◽  
...  
Keyword(s):  
Protein Interactions ◽  
Protein Structures ◽  
Interaction Strength ◽  
Terminal Region ◽  
Spinocerebellar Ataxia Type ◽  
Wild Type ◽  
Binding Interface ◽  
Strength Of Interaction ◽  
The Difference ◽  
Polyq Expansion

Abstract Background Wild-type (wt) polyglutamine (polyQ) regions are implicated in stabilization of protein-protein interactions (PPI). Pathological polyQ expansion, such as that in human Ataxin-1 (ATXN1), that causes spinocerebellar ataxia type 1 (SCA1), results in abnormal PPI. For ATXN1 a larger number of interactors has been reported for the expanded (82Q) than the wt (29Q) protein. Methods To understand how the expanded polyQ affects PPI, protein structures were predicted for wt and expanded ATXN1, as well as, for 71 ATXN1 interactors. Then, the binding surfaces of wt and expanded ATXN1 with the reported interactors were inferred. Results Our data supports that the polyQ expansion alters the ATXN1 conformation and that it enhances the strength of interaction with ATXN1 partners. For both ATXN1 variants, the number of residues at the predicted binding interface are greater after the polyQ, mainly due to the AXH domain. Moreover, the difference in the interaction strength of the ATXN1 variants was due to an increase in the number of interactions at the N-terminal region, before the polyQ, for the expanded form. Conclusions There are three regions at the AXH domain that are essential for ATXN1 PPI. The N-terminal region is responsible for the strength of the PPI with the ATXN1 variants. How the predicted motifs in this region affect PPI is discussed, in the context of ATXN1 post-transcriptional modifications.

Time violating amplitudes in the (3He, p) reactions

1988 ◽  
Vol 66 (7) ◽  
pp. 612-617 ◽  
Author(s):  
Ali E. Khalil
Keyword(s):  
Reaction Mechanism ◽  
Time Reversal ◽  
Born Approximation ◽  
Interaction Strength ◽  
Direct Reaction ◽  
Distorted Wave ◽  
Distorted Wave Born Approximation ◽  
Dwba Calculation ◽  
Hermitian Conjugate ◽  
The Difference

The difference between the polarization (P) of protons in the reaction (3He, [Formula: see text]) and the analyzing power (A) in the inverse reaction ([Formula: see text], 3He) has been calculated using a spin-independent isospin-independent, time reversal violating interaction in the form [α(r)[Formula: see text] + Hermitian conjugate]. The interaction strength is adjusted to be 1% of the time conserving optical potentials. A distorted-wave Born approximation (DWBA) calculation assuming a direct reaction mechanism has been performed. The relative values of the time violating amplitudes have no signatures for any measurable time violating effects.

Dipole moments and solvatochromism of metal complexes: principle photophysical and theoretical approach

2016 ◽  
Vol 18 (27) ◽  
pp. 17822-17826 ◽  
Author(s):  
Galina V. Loukova ◽  
Alexey A. Milov ◽  
Vladimir P. Vasiliev ◽  
Vladimir I. Minkin
Keyword(s):  
Excited State ◽  
Metal Complexes ◽  
Theoretical Approach ◽  
Dipole Moments ◽  
Excited State Dipole Moments ◽  
The Difference

For metal-based compounds, the ground- and excited-state dipole moments and the difference thereof are obtained both experimentally and theoretically.

Dielectric studies. Part XX. Molecular relaxation of some heterocyclic amines in dilute solution

1968 ◽  
Vol 46 (14) ◽  
pp. 2369-2372 ◽  
Author(s):  
J. Crossley ◽  
S. Walker
Keyword(s):  
Relaxation Time ◽  
Dipole Moments ◽  
Relaxation Times ◽  
Lone Pair ◽  
Intermolecular Forces ◽  
Dilute Solution ◽  
Microwave Frequencies ◽  
Heterocyclic Molecules ◽  
Dielectric Constant And Loss ◽  
The Difference

Dielectric constant and loss data have been obtained at microwave frequencies for acridine, 4-methyl-pyridine, phthalazine, quinoline, and isoquinoline in both cyclohexane and p-xylene solution. The data have been used to calculate relaxation times and apparent dipole moments. For phthalazine, quinoline, and isoquinoline in cyclohexane at 50 °C the distribution coefficient is zero and their relaxation times are very similar. Although the axes about which these three molecules may relax lead to different volumes being swept out, no variation in relaxation behavior has been detected, and each system can be characterized by one relaxation time. The relaxation times for all the heterocyclic molecules except quinoline and acridine in p-xylene are appreciably longer than in cyclohexane. Relaxation time values appear a sensitive means of detecting the weak molecular interaction between the amine and the p-xylene. The difference in behavior between the quinoline and acridine as opposed to isoquinoline could be attributed to a more appreciable steric effect in the former two, hindering the approach of the π-electrons of the p-xylene molecules to the hybridized lone pair on the nitrogen atom. No interaction is, in fact, detectable in the case of quinoline and acridine. The importance of allowing for weak intermolecular forces, even in dilute solution, when relaxation values are being anticipated, is emphasized.

Study on the Mechanical Property of 20Cr13 Stainless Steel Barrel Processed by Cold Radial Forging

2016 ◽  
Vol 723 ◽  
pp. 119-124
Author(s):  
Yu Hui Qi ◽  
Xiao Yun Zhang ◽  
Li Xia Fan ◽  
Cheng Xu
Keyword(s):  
Mechanical Properties ◽  
Mechanical Property ◽  
Stainless Steel ◽  
New Technology ◽  
Radial Forging ◽  
Hardness Tester ◽  
The Difference ◽  
Bulging Test ◽  
Increased Strength ◽  
Anisotropic Mechanical Property

The barrel is a key part of automatic weapon. And the cold radial forging progress is a new technology for manufacturing the barrels. It will introduce some changes of the material, such as increased strength, decreased plasticity and introduction of anisotropic mechanical property. It can affect the service performance, so it is necessary to study the difference of tangential and axial mechanical properties of barrel blank and forged barrel. This paper focuses on the research of 20Cr13 stainless steel barrel. The mechanical properties of barrel blank and forged barrel are measured by the tensile, compression and bulging test. And the hardness is measured by Vickers hardness tester. The structural change of 20Cr13 stainless steel also has been observed by metalloscope in the metallographic experiment. It reveals the influence of the cold radial forging progress on the mechanical properties of 20Cr13 stainless steel barrel. And it also provides the reference data of the cold radial forging progress of 20Cr13 stainless steel.

Bonding topology, hydrogen bond strength, and vibrational chemical shifts on hetero-ring hydrogen-bonded complexes — Theoretical insights revisited

2012 ◽  
Vol 90 (4) ◽  
pp. 368-375 ◽  
Author(s):  
Boaz G. Oliveira ◽  
Regiane C. M. U. Araújo
Keyword(s):  
Hydrogen Bond ◽  
Bond Strength ◽  
Chemical Shifts ◽  
Dipole Moments ◽  
Interaction Strength ◽  
Hydrogen Bond Strength ◽  
Electronic Densities ◽  
Bonded Complexes ◽  
Hydrogen Bonded

This work presents a theoretical study about the interaction strength of the hydrogen-bonded complexes C2H4O···HF, C3H6O···HF, C2H4O···HCF3, and C3H6O···HCF3 at the B3LYP/6–311++G(d,p) level. The structures, hydrogen bond energies, charge transfers, and dipole moments of these complexes were analyzed in accordance with routine spectroscopy events, such as the red- and blue-shifts on the stretch frequencies of the proton donors (HF and HCF3). The ChelpG atomic charges were used to quantify the charge-transfer fluxes from electron donor (O) towards to acceptors (HF or HCF3). Moreover, the topological calculations on the basis of the quantum theory of atoms in molecules (QTAIM) approach were also used to unveil the hydrogen bond strength (O···H), mainly in the determination of their electronic densities and Laplacian shapes.

scholarly journals Measuring bulk flows of the intracluster medium in the Perseus and Coma galaxy clusters using XMM-Newton

2020 ◽  
Vol 633 ◽  
pp. A42 ◽  
Author(s):  
J. S. Sanders ◽  
K. Dennerl ◽  
H. R. Russell ◽  
D. Eckert ◽  
C. Pinto ◽  
...  
Keyword(s):  
Galaxy Clusters ◽  
Temporal Variations ◽  
Energy Scale ◽  
Line Of Sight ◽  
Intracluster Medium ◽  
Link Type ◽  
The North ◽  
Systematic Uncertainties ◽  
The Difference ◽  
Width Measurements

We demonstrate a novel technique for calibrating the energy scale of the EPIC-pn detector on XMM-Newton, which allows us to measure bulk flows in the intracluster medium (ICM) of the Perseus and Coma galaxy clusters. The procedure uses the fluorescent instrumental background lines present in all observations, in particular, Cu-Kα. By studying their spatial and temporal variations, in addition to incorporating calibration observations, we refined the absolute energy scale of the detector to better than 150 km s−1 at the Fe-K line, a large improvement over the nominal calibration accuracy of 550 km s−1. With our calibration, we mapped the bulk motions over much of the central 1200 and 800 kpc of Perseus and Coma, respectively, in spatial regions down to 65 and 140 kpc size. We cross-checked our procedure by comparing our measurements with those found in Perseus by Hitomi for an overlapping 65 kpc square region, finding consistent results. For Perseus, there is a relative line-of-sight velocity increase of 480 ± 210 km s−1 (1σ) at a radius of 250 kpc east of the nucleus. This region is associated with a cold front, providing direct evidence of the ICM sloshing in the cluster potential well. Assuming the intrinsic distribution of bulk motions is Gaussian, its width is 214 ± 85 km s−1, excluding systematic uncertainties. Removing the sloshing region, this is reduced to 20–150 km s−1, which is similar in magnitude to the Hitomi line width measurements in undisturbed regions. In Coma, the line-of-sight velocity of the ICM varies between the velocities of the two central galaxies. Maps of the gas velocity and metallicity provide clues about the merger history of the Coma, with material to the north and east of the cluster core having a velocity similar to NGC 4874, while that to the south and west has velocities close to NGC 4889. Our results highlight the difference between a merging system, such as Coma, where we observe a ∼1000 km s−1 range in velocity, and a relatively relaxed system, such as Perseus, with much weaker bulk motions.

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