Squeezing xenon into phenylether bis-urea nanochannels

2015 ◽  
Vol 93 (9) ◽  
pp. 1031-1034 ◽  
Author(s):  
Clifford R. Bowers ◽  
Muslim Dvoyashkin ◽  
Sahan R. Salpage ◽  
Christopher Akel ◽  
Hrishi Bhase ◽  
...  
Keyword(s):  
Gas Phase ◽  
Persistence Length ◽  
Channel Structure ◽  
Chemical Shift Tensor ◽  
Cross Sectional ◽  
Elliptical Cross ◽  
One Dimensional ◽  
Single File ◽  
Nmr Data ◽  
Pattern Characteristic

One-dimensional nanochannels, hundreds of microns in persistence length but with elliptical cross-sectional dimensions of only ∼3.7 Å × 4.8 Å, are formed by the columnar assembly of phenylether bis-urea macrocycles. Hyperpolarized Xe-129 NMR is utilized to investigate the Xe atom packing and Xe diffusion inside the needle shaped crystals. The elliptical channel structure produces a Xe-129 powder pattern characteristic of an asymmetric chemical shift tensor extending to well over 300 ppm with respect to the gas phase, reflecting the highly anisotropic electronic environment and extreme confinement of the atom. Consistent with the simple geometrical criterion, hyperpolarized tracer exchange NMR data reveals single-file diffusion in the bis-urea nanochannels.

The Exact One-Dimensional Theory for End-Loaded Fully Anisotropic Beams of Narrow Rectangular Cross Section

2001 ◽  
Vol 68 (6) ◽  
pp. 865-868 ◽  
Author(s):  
P. Ladeve`ze ◽  
J. G. Simmonds
Keyword(s):  
Cross Section ◽  
Plane Stress ◽  
Rectangular Cross Section ◽  
Dimensional Theory ◽  
Explicit Formulas ◽  
Cross Sectional ◽  
Rectangular Shape ◽  
One Dimensional ◽  
Anisotropic Elastic ◽  
Derivatives Of

The exact theory of linearly elastic beams developed by Ladeve`ze and Ladeve`ze and Simmonds is illustrated using the equations of plane stress for a fully anisotropic elastic body of rectangular shape. Explicit formulas are given for the cross-sectional material operators that appear in the special Saint-Venant solutions of Ladeve`ze and Simmonds and in the overall beamlike stress-strain relations between forces and a moment (the generalized stress) and derivatives of certain one-dimensional displacements and a rotation (the generalized displacement). A new definition is proposed for built-in boundary conditions in which the generalized displacement vanishes rather than pointwise displacements or geometric averages.

Long waves in a straight channel with non-uniform cross-section

2015 ◽  
Vol 770 ◽  
pp. 156-188 ◽  
Author(s):  
Patricio Winckler ◽  
Philip L.-F. Liu
Keyword(s):  
Boundary Layer ◽  
Wave Propagation ◽  
Cross Section ◽  
Three Dimensional ◽  
Channel Cross Section ◽  
Cross Sectional ◽  
New Model ◽  
One Dimensional ◽  
Uniform Channel ◽  
The Cross

A cross-sectionally averaged one-dimensional long-wave model is developed. Three-dimensional equations of motion for inviscid and incompressible fluid are first integrated over a channel cross-section. To express the resulting one-dimensional equations in terms of the cross-sectional-averaged longitudinal velocity and spanwise-averaged free-surface elevation, the characteristic depth and width of the channel cross-section are assumed to be smaller than the typical wavelength, resulting in Boussinesq-type equations. Viscous effects are also considered. The new model is, therefore, adequate for describing weakly nonlinear and weakly dispersive wave propagation along a non-uniform channel with arbitrary cross-section. More specifically, the new model has the following new properties: (i) the arbitrary channel cross-section can be asymmetric with respect to the direction of wave propagation, (ii) the channel cross-section can change appreciably within a wavelength, (iii) the effects of viscosity inside the bottom boundary layer can be considered, and (iv) the three-dimensional flow features can be recovered from the perturbation solutions. Analytical and numerical examples for uniform channels, channels where the cross-sectional geometry changes slowly and channels where the depth and width variation is appreciable within the wavelength scale are discussed to illustrate the validity and capability of the present model. With the consideration of viscous boundary layer effects, the present theory agrees reasonably well with experimental results presented by Chang et al. (J. Fluid Mech., vol. 95, 1979, pp. 401–414) for converging/diverging channels and those of Liu et al. (Coast. Engng, vol. 53, 2006, pp. 181–190) for a uniform channel with a sloping beach. The numerical results for a solitary wave propagating in a channel where the width variation is appreciable within a wavelength are discussed.

scholarly journals Multiphase modeling of nitrate photochemistry in the quasi-liquid layer (QLL): implications for NO<sub>x</sub> release from the Arctic and coastal Antarctic snowpack

2008 ◽  
Vol 8 (16) ◽  
pp. 4855-4864 ◽  
Author(s):  
C. S. Boxe ◽  
A. Saiz-Lopez
Keyword(s):  
Gas Phase ◽  
Liquid Layer ◽  
Solar Spectrum ◽  
The Arctic ◽  
Transfer Model ◽  
Multiphase Model ◽  
Gas Phase Reactions ◽  
One Dimensional ◽  
Quasi Liquid Layer ◽  
Summer Range

Abstract. We utilize a multiphase model, CON-AIR (Condensed Phase to Air Transfer Model), to show that the photochemistry of nitrate (NO3−) in and on ice and snow surfaces, specifically the quasi-liquid layer (QLL), can account for NOx volume fluxes, concentrations, and [NO]/[NO2] (γ=[NO]/[NO2]) measured just above the Arctic and coastal Antarctic snowpack. Maximum gas phase NOx volume fluxes, concentrations and γ simulated for spring and summer range from 5.0×104 to 6.4×105 molecules cm−3 s−1, 5.7×108 to 4.8×109 molecules cm−3, and ~0.8 to 2.2, respectively, which are comparable to gas phase NOx volume fluxes, concentrations and γ measured in the field. The model incorporates the appropriate actinic solar spectrum, thereby properly weighting the different rates of photolysis of NO3− and NO2−. This is important since the immediate precursor for NO, for example, NO2−, absorbs at wavelengths longer than nitrate itself. Finally, one-dimensional model simulations indicate that both gas phase boundary layer NO and NO2 exhibit a negative concentration gradient as a function of height although [NO]/[NO2] are approximately constant. This gradient is primarily attributed to gas phase reactions of NOx with halogens oxides (i.e. as BrO and IO), HOx, and hydrocarbons, such as CH3O2.

Intermolecular Interactions of Xe Atoms Confined in One-dimensional Nanochannels of Tris(o-phenylenedioxy)cyclotriphosphazene as Studied by High-pressure 129Xe NMR

2003 ◽  
Vol 58 (12) ◽  
pp. 727-734 ◽  
Author(s):  
Hirokazu Kobayashi ◽  
Takahiro Ueda ◽  
Keisuke Miyakubo ◽  
Taro Eguchi
Keyword(s):  
High Pressure ◽  
Nmr Spectroscopy ◽  
Chemical Shift ◽  
Pressure Dependence ◽  
Average Distance ◽  
Chemical Shift Tensor ◽  
Axially Symmetric ◽  
One Dimensional ◽  
129Xe Nmr ◽  
The One

The pressure dependence of the 129Xe chemical shift tensor confined in the Tris(o-phenylenedioxy) cyclotriphosphazene (TPP) nanochannel was investigated by high-pressure 129Xe NMR spectroscopy. The observed 129Xe spectrum in the one-dimensional TPP nanochannel (0.45 nm in diameter) exhibits a powder pattern broadened by an axially symmetric chemical shift tensor. As the pressure increases from 0.02 to 7.0 MPa, a deshielding of 90 ppm is observed for the perpendicularcomponent of the chemical shift tensor δ⊥, whereas a deshielding of about 30 ppm is observed for the parallel one, δ‖. This suggests that the components of the chemical shift tensor, δ‖ and δ⊥, are mainly dominated by the Xe-wall and Xe-Xe interaction, respectively. Furthermore, the effect of helium, which is present along with xenon gas, on the 129Xe chemical shift is examined in detail. The average distance between the Xe atoms in the nanochannel is estimated to be 0.54 nm. This was found by using δ⊥ at the saturated pressure of xenon, and comparing the increment of the chemicalshift value in δ⊥ to that of a β -phenol/Xe compound.

scholarly journals Guest-induced fluorescence property of macrocyclic boronic ester

2014 ◽  
Vol 70 (a1) ◽  
pp. C672-C672
Author(s):  
Haruki Sugiyama ◽  
Kohei Johmoto ◽  
Hidehiro Uekusa ◽  
Yuji Kikuchi ◽  
Hiroki Takahagi ◽  
...  
Keyword(s):  
Crystal Packing ◽  
Uv Light ◽  
Condensation Reaction ◽  
Fluorescence Property ◽  
Channel Structure ◽  
Diffusion Method ◽  
Blue Color ◽  
Guest Molecules ◽  
One Dimensional ◽  
Naphthalene Molecule

Macrocyclic boronic esters (1) are obtained as a self-assembled molecule by condensation reaction between rac-tetrol (2) and 1,4-naphthalenediboronic acid (3) in the presence of toluene molecule [1]. In the crystal, this macrocyclic molecules form a charasteristic one dimensional channel structure that accommodates various small molecules. Interestingly, reversible desorption / absorption phenomena of guest molecules is observed without significant crystal packing change, meaning this crystal may have guest storage, separation, and catalytic abilities. In the course of exploring further functional aspects of the molecule, we give fluorescence property to this crystal by inclusion of acene molecules into this robust one dimensional channel structure. Naphthalene inclusion crystal was obtained by the diffusion method. The crystal structure is isostructural to known crystals, that is, a naphthalene molecule is included in a channel and sandwiched by two naphthalene moieties of the macrocyclic molecule (inter planar distance is about 3.6 angstrom). Under UV light, a blue color fluorescence observed in this crystal, suggesting the guest naphthalene molecule contributes the fluorescence property. After heating by 200 degrees C, the naphthalene was released to leave isostructural apohost crystal without fluorescence property. However, by naphthalene vapor exposure to the apohost crystal, the fluorescence property was recovered, which means naphthalene desorption and absorption are possible in crystalline state. Moreover Anthracene and Tetracene inclusion crystal were obtained, and they also showed light blue and yellow color fluorescence under UV light, respectively. Thus, the fluorescence function was successfully realized by inclusion of acene molecule in the one dimensional channel of the crystals, and furthermore the fluorescent color can be controlled by changing acene molecules.

scholarly journals How to Evaluate Digital Leadership: A Cross-sectional Study

2021 ◽  
Author(s):  
Kevin Claassen ◽  
Dominique Rodil Dos Anjos ◽  
Jan Kettschau ◽  
Horst Christoph Broding
Keyword(s):  
Construct Validity ◽  
Online Survey ◽  
Leadership Skills ◽  
Principal Component ◽  
Cross Sectional Study ◽  
Working Environment ◽  
Cross Sectional ◽  
One Dimensional ◽  
Leadership Competence ◽  
Transformation Processes

Abstract Background: With the increasing digitalization of the working environment, the demands on managers are changing fundamentally to the point of an emerging field of research in digital leadership. Municipal administrations are particularly affected by the digital transformation processes. Therefore, a score to measure the construct of digital leadership competence in the context of virtual-based workstation was developed and tested.Methods: Based of an online survey with n = 546 employees at virtual-based workstations in municipal administrations in 2020, the instrument is tested regarding selectivity (coefficients), dimensionality (principal component analysis), homogeneity (inter-product-moment correlations), reliability (Cronbach's α) and construct validity (correlation with general leadership skills).Results: The instrument can be considered selective, one-dimensional, homogeneous, reliable and constructively valid in the sense of the formulated hypotheses. By integrating the employees‘ perspective, the instrument aims to be one of the first of its kind to initiate a scientific further discourse. Among other things, the categorization of the co-determination component as either traditional or digital leadership can be discussed.Conclusions: The developed instrument for measuring digital leadership performs well concerning the aspects of discriminatory power, one-dimensionality, homogeneity, reliability as well as construct validity. It aims to induce further research and a scientific discourse on the topic of health-oriented leadership within the world of work 4.0.

scholarly journals SIMULATION OF SINGLE CRYSTAL ONE DIMENSIONAL ZnO RODS ARRAY GROWTH PROCESS

2021 ◽  
Author(s):  
Andrey Sharapov ◽  
Igor Matyushkin
Keyword(s):  
Zinc Oxide ◽  
Single Crystal ◽  
Gas Phase ◽  
Growth Process ◽  
Silicon Oxide ◽  
Phase Growth ◽  
One Dimensional ◽  
Zno Rods

In this work, the formation of zinc oxide arrows by gas-phase growth on the surface of silicon oxide is simulated.

Statistical Thermodynamics and Surface Phase Transitions of Interacting Particles Adsorbed on One-Dimensional Channels Arranged in a Triangular Cross-Sectional Structure

2009 ◽  
Vol 150 ◽  
pp. 73-100 ◽  
Author(s):  
P.M. Pasinetti ◽  
F. Romá ◽  
J.L. Riccardo ◽  
A.J. Ramirez-Pastor
Keyword(s):  
Monte Carlo ◽  
Interaction Energy ◽  
Lattice Gas ◽  
Nearest Neighbor ◽  
Single Channel ◽  
Scaling Analysis ◽  
Surface Phase ◽  
Cross Sectional ◽  
One Dimensional ◽  
Sectional Structure

Monte Carlo simulations and finite-size scaling analysis have been carried out to study the critical behavior in a submonolayer lattice-gas, which mimics a nanoporous environment. In this model, one-dimensional chains of atoms were arranged in a triangular cross-sectional structure. Two kinds of lateral interaction energies have been considered: (1) wL, interaction energy between nearest-neighbor particles adsorbed along a single channel and (2) wT, interaction energy between particles adsorbed across nearest-neighbor channels. We focus on the case of repulsive transverse interactions (wT > 0), where a rich variety of structural orderings are observed in the adlayer, depending on the value of the parameters kBT/wT (kB being the Boltzmann constant) and wL /wT. For wL /wT = 0, successive planes are uncorrelated, the system is equivalent to the triangular lattice, and the well-known [ ] ordered phase is found at low temperatures and a coverage, , of 1/3 [2/3]. In the more general case (wL /wT  0), the competition between interactions along a single channel and the transverse coupling between sites in neighboring channels leads to a three-dimensional adsorbed layer. Consequently, the and structures “propagate” along the channels and new ordered phases appear in the adlayer. The influence of each ordered phase on adsorption isotherms, differential heat of adsorption and configurational entropy of the adlayer has been analyzed and discussed in the context of the lattice-gas theory. Finally, the Monte Carlo technique was combined with the recently reported free energy minimization criterion approach (FEMCA) [F. Romá et al.: Phys. Rev. B Vol. 68 (2003), art. no. 205407] to predict the critical temperatures of the surface-phase transformations occurring in the adsorbate. The excellent qualitative agreement between simulated data and FEMCA results allows us to interpret the physical meaning of the mechanisms underlying the observed transitions.

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