BOND EQUILIBRIUM THEORY IN COVALENTLY BONDED ALLOYS

1981 ◽  
Vol 42 (C4) ◽  
pp. C4-201-C4-204
Author(s):  
M. Cutler
Keyword(s):  
Equilibrium Theory ◽  
Covalently Bonded

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.

Morphological behavior of compatibilized ternary blends prepared by mechanical mixing

1993 ◽  
Vol 51 ◽  
pp. 1200-1201
Author(s):  
S.D. Smith ◽  
R.J. Spontak ◽  
D.H. Melik ◽  
S.M. Buehler ◽  
K.M. Kerr ◽  
...  
Keyword(s):  
Interfacial Adhesion ◽  
Diblock Copolymers ◽  
Ternary Blends ◽  
Mechanical Mixing ◽  
Design Considerations ◽  
Covalently Bonded ◽  
Homopolymer Blends ◽  
Emulsifying Agent ◽  
Surface Active ◽  
Low Entropy

When blended together, homopolymers A and B will normally macrophase-separate into relatively large (≫1 μm) A-rich and B-rich phases, between which exists poor interfacial adhesion, due to a low entropy of mixing. The size scale of phase separation in such a blend can be reduced, and the extent of interfacial A-B contact and entanglement enhanced, via addition of an emulsifying agent such as an AB diblock copolymer. Diblock copolymers consist of a long sequence of A monomers covalently bonded to a long sequence of B monomers. These materials are surface-active and decrease interfacial tension between immiscible phases much in the same way as do small-molecule surfactants. Previous studies have clearly demonstrated the utility of block copolymers in compatibilizing homopolymer blends and enhancing blend properties such as fracture toughness. It is now recognized that optimization of emulsified ternary blends relies upon design considerations such as sufficient block penetration into a macrophase (to avoid block slip) and prevention of a copolymer multilayer at the A-B interface (to avoid intralayer failure).

Macroeconomic Equilibrium Theory in the Context of Methodological Problems of Contemporary Economic Science

2008 ◽  
pp. 77-88
Author(s):  
M. Likhachev
Keyword(s):  
Empirical Analysis ◽  
Equilibrium States ◽  
Equilibrium Theory ◽  
Economic Systems ◽  
Economic Science ◽  
The Real ◽  
Theoretical Status ◽  
Methodological Problems ◽  
Real Stability

The article is devoted to the analysis of methodological problems in using the conception of macroeconomic equilibrium in contemporary economics. The author considers theoretical status and relevance of equilibrium conception and discusses different areas and limits of applicability of the equilibrium theory. Special attention is paid to different epistemological criteria for this theory taking into account both empirical analysis of the real stability of economic systems and the problem of unobservability of equilibrium states.

Integrating economic cycles theory with equilibrium theory (the second half of the 1920s and 1930s) and N. D. Kondratiev’s project of economic dynamics

2014 ◽  
pp. 22-39 ◽  
Author(s):  
N. Makasheva
Keyword(s):  
Economic Theory ◽  
Equilibrium Theory ◽  
Economic Dynamics ◽  
Economic Cycles

The article considers the ways to overcome the methodological gap between the analysis of economic cycles and the pure economic theory as suggested by the Western economists in the 1920s and 1930s. In this context, N. D. Kondratiev’s project of economic dynamics is analyzed, which implied a radically different vision of the opportunities to solve this problem.

Some Developments in Economic Theory Since 1940: An Eyewitness Account

2010 ◽  
pp. 4-23 ◽  
Author(s):  
K. Arrow
Keyword(s):  
Economic Theory ◽  
General Equilibrium ◽  
Equilibrium Theory ◽  
General Equilibrium Theory ◽  
Economics Of Information ◽  
Modern Economic ◽  
Eyewitness Account ◽  
Theory Uncertainty ◽  
Professional Formation

The article considers the evolution of some branches of modern economic theory from the perspective of the authors biography as a scientist and his professional formation. It describes problems of econometrics, general equilibrium theory, uncertainty, economics of information, and growth. It is shown how different authors representing various fields came to similar conclusions simultaneously and independently, what were the problems, in response to which economists of the second half of last century developed their theories, and what were the contexts of such development.

Thermally-Induced Dehydrogenative Coupling of Organosilanes and H-Terminated Silicon Quantum Dots onto Germanane Surfaces

2020 ◽  
Author(s):  
Haoyang Yu ◽  
Alyxandra Thiessen ◽  
Md Asjad Hossain ◽  
Marc Julian Kloberg ◽  
Bernhard Rieger ◽  
...  
Keyword(s):  
2D Materials ◽  
Future Generation ◽  
Optical Devices ◽  
Surface Reactivity ◽  
Organic Monolayers ◽  
Present Contribution ◽  
Thermally Induced ◽  
Dehydrogenative Coupling ◽  
Silicon Quantum Dot ◽  
Covalently Bonded

<div><div><div><p>Covalently bonded organic monolayers play important roles in defining the solution processability, ambient stability, and electronic properties of two-dimensional (2D) materials such as Ge nanosheets (GeNSs); they also hold promise of providing avenues for the fabrication of future generation electronic and optical devices. Functionalization of GeNS normally involves surface moieties linked through covalent Ge−C bonds. In the present contribution we extend the scope of surface linkages to include Si−Ge bonding and present the first demonstration of heteronuclear dehydrocoupling of organosilanes to hydride-terminated GeNSs obtained from the deintercalation and exfoliation of CaGe2. We further exploit this new surface reactivity and demonstrated the preparation of directly bonded silicon quantum dot-Ge nanosheet hybrids.</p></div></div></div>

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