scholarly journals Microphase separation in active filament systems maintained by cyclic dynamics of cluster size and order

2021 ◽  
Vol 3 (1) ◽  
Author(s):  
Lorenz Huber ◽  
Timo Krüger ◽  
Erwin Frey
Keyword(s):  
Cluster Size ◽  
Microphase Separation ◽  
Cyclic Dynamics

Production and STEM examination of controlled-size silver clusters

1983 ◽  
Vol 41 ◽  
pp. 338-339
Author(s):  
M. A. Listvan ◽  
R. P. Andres
Keyword(s):  
Cluster Size ◽  
Metal Clusters ◽  
Experimental Parameter ◽  
Carbon Films ◽  
Metal Species ◽  
Silver Clusters ◽  
Free Jet ◽  
Size Dependent ◽  
Cluster Properties ◽  
Controllable Size

Knowledge of the function and structure of small metal clusters is one goal of research in catalysis. One important experimental parameter is cluster size. Ideally, one would like to produce metal clusters of regulated size in order to characterize size-dependent cluster properties.A source has been developed which is capable of producing microscopic metal clusters of controllable size (in the range 5-500 atoms) This source, the Multiple Expansion Cluster Source, with a Free Jet Deceleration Filter (MECS/FJDF) operates as follows. The bulk metal is heated in an oven to give controlled concentrations of monomer and dimer which were expanded sonically. These metal species were quenched and condensed in He and filtered to produce areosol particles of a controlled size as verified by mass spectrometer measurements. The clusters were caught on pre-mounted, clean carbon films. The grids were then transferred in air for microscopic examination. MECS/FJDF was used to produce two different sizes of silver clusters for this study: nominally Ag6 and Ag50.

Morphological studies of linear (AB)n multiblock copolymers and their blends

1992 ◽  
Vol 50 (1) ◽  
pp. 384-385
Author(s):  
Richard J. Spontak ◽  
Steven D. Smith ◽  
Arman Ashraf
Keyword(s):  
Electron Microscopy ◽  
Microphase Separation ◽  
Multiblock Copolymers ◽  
First Order ◽  
Morphological Studies ◽  
Transmission Electron ◽  
First Order Phase Transition ◽  
Covalently Bonded ◽  
Total Molecular Weight ◽  
First Order Phase

Block copolymers are composed of sequences of dissimilar chemical moieties covalently bonded together. If the block lengths of each component are sufficiently long and the blocks are thermodynamically incompatible, these materials are capable of undergoing microphase separation, a weak first-order phase transition which results in the formation of an ordered microstructural network. Most efforts designed to elucidate the phase and configurational behavior in these copolymers have focused on the simple AB and ABA designs. Few studies have thus far targeted the perfectly-alternating multiblock (AB)n architecture. In this work, two series of neat (AB)n copolymers have been synthesized from styrene and isoprene monomers at a composition of 50 wt% polystyrene (PS). In Set I, the total molecular weight is held constant while the number of AB block pairs (n) is increased from one to four (which results in shorter blocks). Set II consists of materials in which the block lengths are held constant and n is varied again from one to four (which results in longer chains). Transmission electron microscopy (TEM) has been employed here to investigate the morphologies and phase behavior of these materials and their blends.

Cluster size effects revisited

1995 ◽  
Vol 92 ◽  
pp. 205-225 ◽  
Author(s):  
J Jortner
Keyword(s):  
Size Effects ◽  
Cluster Size

Design a Cellular System with Different Cluster Size and Investigate the Co Channel Interference Assuming a Limited Geographical Area with Fixed Channel Assignment Strategy

2017 ◽  
Vol 3 (04) ◽  
Author(s):  
Md.Taz Uddin, Ahmed al Marzean, Md Rafiqul Islam, Shahjahan Ahmed
Keyword(s):  
Channel Assignment ◽  
Cluster Size ◽  
Geographical Area ◽  
Cellular System ◽  
Communication Industry ◽  
Mobile Operator ◽  
Channel Interference ◽  
Assignment Strategy ◽  
Fixed Channel Assignment ◽  
Mobile Communication Industry

There are different communication standards in present mobile communication industry. Each of this standards has its own feature, architecture, and channel assignment strategies. Each mobile operator uses one of any standard and their aim is to support as much user as possible to communicate with tolerable interference. For that reason they use different cluster size and frequency planning to cover entire geographical area. To reuse the given bandwidth within the entire geographical area some cells uses same sets of frequency and interference arise when the distance between these cells is small. Also when distance is large then capacity is going low. In this thesis our work is to investigation the co channel interference among different cluster size assuming a limited sub urban geographical area in a cellular GSM network. Also we calculate the number of users using each of this cluster size and finally design a cellular system in this geographical area using best results (minimum interference and maximum capacity).

A simple method to determine the mean cluster size in a molecular beam

1991 ◽  
Vol 21 (3) ◽  
pp. 265-269 ◽  
Author(s):  
J. Cuvellier ◽  
P. Meynadier ◽  
P. Pujo ◽  
O. Sublemontier ◽  
J-P Visticot ◽  
...  
Keyword(s):  
Cluster Size ◽  
Molecular Beam ◽  
Simple Method ◽  
The Mean
Sign in / Sign up

Export Citation Format

Share Document