Monte Carlo study of tethered chains in spherical volumes

1995 ◽  
Vol 99 (38) ◽  
pp. 14108-14116 ◽  
Author(s):  
Karel Prochazka
2004 ◽  
Vol 120 (18) ◽  
pp. 8831-8840 ◽  
Author(s):  
Radu Descas ◽  
Jens-Uwe Sommer ◽  
Alexander Blumen

1994 ◽  
Vol 59 (4) ◽  
pp. 803-819 ◽  
Author(s):  
Zuzana Limpouchová ◽  
Karel Procházka

Conformations of tethered chains in restricted spherical volumes with an increasing radius were studied by Monte Carlo simulations. Simulations were performed on a tetrahedral lattice at relatively high densities of the occupied lattice sites. A simultaneous self-avoiding walk of all tethered chains creates the starting conformations of the multi-chain system which are futher equilibrated by a modified algorithm similar to that of Siepmann and Frenkel. In this paper, only a geometric excluded volume effect of segments is considered. Selectively chosen series of data for changing numbers of chains, N, their lengths, L, and radii of the sphere, R, give information on the system behavior under various conditions. In this part of our systematic study of tethered chains in constrained volumes, we present angular distribution functions of the end-to-end, end-to-gravity center distances, etc. for system studied in previous paper. The second class of studied conformational characteristics are the distributions of projections of the end-to-end vectors into the selected directions (i.e. the radial direction and the direction of the first-to-second polymer segment connection).


1994 ◽  
Vol 59 (10) ◽  
pp. 2166-2189 ◽  
Author(s):  
Karel Procházka ◽  
Zuzana Limpouchová

Monte Carlo study of tethered chain conformations in spherical cavities was performed in a relatively broad range of average segment densities (i.e. numbers of tethered chains with increasing length in the sphere). Simulations were performed on a tetrahedral lattice using (i) an equilibrated self-avoiding walk for systems containing a single tethered chain with increasing length, and (ii) a simultaneous self-avoiding walk of many tethered chains in the spherical cavity together with equilibration of the system which was performed by a modified algorithm similar to that of Siepmann and Frenkel. Only a geometric excluded volume effect of segments was considered (i.e. the prohibition principle of a double occupancy of one lattice site by two different segments). Various distribution functions (e.g. distribution of the end-to-end and the end-to-gravity center distances and their orientations with respect either to the radial direction, or to the direction of the first-to-second segment connection, etc.) were calculated and the effect of increasing average segment density in the sphere on conformational characteristics of individual chains was studied. It was found that conformational and orientational properties of relatively short tethered chains are only little affected by increasing segment density (i.e. by the number of chains in the spherical cavity), whereas arrangements of long tethered chains are significantly influenced by the density of the system.


2006 ◽  
Vol 124 (9) ◽  
pp. 094701 ◽  
Author(s):  
Radu Descas ◽  
Jens-Uwe Sommer ◽  
Alexander Blumen

Methodology ◽  
2013 ◽  
Vol 9 (1) ◽  
pp. 1-12 ◽  
Author(s):  
Holger Steinmetz

Although the use of structural equation modeling has increased during the last decades, the typical procedure to investigate mean differences across groups is still to create an observed composite score from several indicators and to compare the composite’s mean across the groups. Whereas the structural equation modeling literature has emphasized that a comparison of latent means presupposes equal factor loadings and indicator intercepts for most of the indicators (i.e., partial invariance), it is still unknown if partial invariance is sufficient when relying on observed composites. This Monte-Carlo study investigated whether one or two unequal factor loadings and indicator intercepts in a composite can lead to wrong conclusions regarding latent mean differences. Results show that unequal indicator intercepts substantially affect the composite mean difference and the probability of a significant composite difference. In contrast, unequal factor loadings demonstrate only small effects. It is concluded that analyses of composite differences are only warranted in conditions of full measurement invariance, and the author recommends the analyses of latent mean differences with structural equation modeling instead.


2011 ◽  
Author(s):  
Patrick J. Rosopa ◽  
Amber N. Schroeder ◽  
Jessica Doll

1993 ◽  
Vol 3 (9) ◽  
pp. 1719-1728
Author(s):  
P. Dollfus ◽  
P. Hesto ◽  
S. Galdin ◽  
C. Brisset

1987 ◽  
Vol 48 (C5) ◽  
pp. C5-199-C5-202
Author(s):  
T. MIYASAKI ◽  
K. AIZAWA ◽  
H. AOKI ◽  
C. ITOH ◽  
M. OKAZAKI

Sign in / Sign up

Export Citation Format

Share Document