Molecular self-assemblies. 2. A computational method for the prediction of the structure of one-dimensional screw, glide, and inversion molecular aggregates and implications for the packing of molecules in monolayers and crystals

1994 ◽  
Vol 116 (2) ◽  
pp. 455-470 ◽  
Author(s):  
Jerry Perlstein
Keyword(s):  
Computational Method ◽  
Molecular Aggregates ◽  
One Dimensional ◽  
And Inversion

Effective Shear Area in One Dimensional Ship Hull Finite Element Models to Predict Natural Frequencies of Vibration

2013 ◽  
Author(s):  
Osvaldo Pinheiro de Souza e Silva ◽  
Severino Fonseca da Silva Neto ◽  
Ilson Paranhos Pasqualino ◽  
Antonio Carlos Ramos Troyman
Keyword(s):  
Finite Element ◽  
Natural Frequencies ◽  
Three Dimensional ◽  
Experimental Tests ◽  
Numerical Results ◽  
Computational Method ◽  
Scale Model ◽  
Dimensional Model ◽  
One Dimensional ◽  
Shear Area

This work discusses procedures used to determine effective shear area of ship sections. Five types of ships have been studied. Initially, the vertical natural frequencies of an acrylic scale model 3m in length in a laboratory at university are obtained from experimental tests and from a three dimensional numerical model, and are compared to those calculated from a one dimensional model which the effective shear area was calculated by a practical computational method based on thin-walled section Shear Flow Theory. The second studied ship was a ship employed in midshipmen training. Two models were made to complement some studies and vibration measurements made for those ships in the end of 1980 decade when some vibration problems in them were solved as a result of that effort. Comparisons were made between natural frequencies obtained experimentally, numerically from a three dimensional finite element model and from a one dimensional model in which effective shear area is considered. The third and fourth were, respectively, a tanker ship and an AHTS (Anchor Handling Tug Supply) boat, both with comparison between three and one dimensional models results out of water. Experimental tests had been performed in these two ships and their results were used in other comparison made after the inclusion of another important effect that acts simultaneously: the added mass. Finally, natural frequencies experimental and numerical results of a barge are presented. The natural frequencies numerical results of vertical hull vibration obtained from these approximations of effective shear areas for the five ships are finally discussed.

Polysulfonylamine, CLXXXV. Wasserstoffbrücken oder Halogenbrücken? Die supramolekularen Strukturen von 3-Bromanilinium- und 4-Bromanilinium-di(4-brombenzolsulfonyl)amid / Polysulfonylamines, CLXXXV. Hydrogen Bonding or Halogen Bonding? The Supramolecular Structures of 3-Bromoanilinium and 4-Bromoanilinium Di(4-bromobenzenesulfonyl)amides

2008 ◽  
Vol 63 (8) ◽  
pp. 954-962 ◽  
Author(s):  
Virginia Lozano ◽  
Matthias Freytag ◽  
Peter G. Jones ◽  
Armand Blaschette
Keyword(s):  
Hydrogen Bonding ◽  
Hydrogen Bonds ◽  
Halogen Bonding ◽  
Database Search ◽  
Type I ◽  
Two Dimensional ◽  
Chemical Difference ◽  
One Dimensional ◽  
Phenyl Rings ◽  
And Inversion

This study characterizes the supramolecular synthons that dominate the interionic organization of 3-bromoanilinium di(4-bromobenzenesulfonyl)amide (1) and the corresponding 4-bromoanilinium salt (2) in their respective crystal structures (1: orthorhombic, Pbca, Z´ = 1; 2: monoclinic, P21/n, Z´ = 1). Although these compounds contain N+-H donors and C-Br groups in equal numbers, their ion packings are exclusively governed by classical, and mostly bifurcated, hydrogen bonds of the type N+-H···O=S/N−, whereas halogen bonding C-Br···O=S/N− is absent from both structures. The isomerism of the cations, which is the only chemical difference between 1 and 2, drives the hydrogen bonds to form a network that is two-dimensional in 1, but one-dimensional in 2. The resulting layers or strands are coherently built up from hydrophilic internal regions consisting of NH3 + and (SO2)2N− groups, external hydrophobic domains of phenyl rings, and peripherically projecting bromine atoms. As the hydrophobic groups from adjacent layers or strands do not interdigitate, the bromine atoms are sterically available to form short Br・ ・ ・Br interlayer contacts of quasi-type I in 1 and inversion symmetric Br4 interstrand quadrilaterals in 2. The results of a database search for quadrilateral (C-Br)4 synthons are also presented.

Third-Order Nonlinear Optical Properties of One-Dimensional Open-Shell Molecular Aggregates Composed of Phenalenyl Radicals

2014 ◽  
Vol 20 (35) ◽  
pp. 11129-11136 ◽  
Author(s):  
Kyohei Yoneda ◽  
Masayoshi Nakano ◽  
Kotaro Fukuda ◽  
Hiroshi Matsui ◽  
Shota Takamuku ◽  
...  
Keyword(s):  
Optical Properties ◽  
Nonlinear Optical ◽  
Open Shell ◽  
Nonlinear Optical Properties ◽  
Molecular Aggregates ◽  
Third Order ◽  
One Dimensional
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