The Experts below are selected from a list of 264 Experts worldwide ranked by ideXlab platform
Aoqing Tang - One of the best experts on this subject based on the ideXlab platform.
-
Curing theory of A f -A g type free radical polymerization (II)
Science China-chemistry, 1999Co-Authors: Haijun Wang, Ze-sheng Li, Zhong-yuan Lu, Xu-ri Huang, Aoqing TangAbstract:By means of polymer statistical theory, the sol fraction and the gelation condition of A f -A g type nonlinear free radical polymerization are obtained by introducing the probabilities with respect to initiation and chain addition. With Lagrange expansion theorem, the Equilibrium Number fraction distribution of A f -Ag type is obtained, and its invariant property is proved. Moreover, the evaluation of average polymer quantities for post-gel regime is simplified by this invariant property.
-
Curing theory of A f -A g type free radical polymerization (I)──Distribution function and its invariant property
Science China-chemistry, 1998Co-Authors: Haijun Wang, Ze-sheng Li, Zhong-yuan Lu, Xu-ri Huang, Aoqing TangAbstract:By means of polymer statistical theory, the sol fraction and the gelation condition of A f-A g type nonlinear free radical polymerization are obtained by introducing the probabilities with respect to initiation and chain addition. With Lagrange expansion theorem, the Equilibrium Number fraction distribution of A f-A g type is obtained, and its invariant property is proved. Moreover, the evaluation of average polymer quantities for post-gel regime is simplified by this invariant property.
Ze-sheng Li - One of the best experts on this subject based on the ideXlab platform.
-
Curing theory of A f -A g type free radical polymerization (II)
Science China-chemistry, 1999Co-Authors: Haijun Wang, Ze-sheng Li, Zhong-yuan Lu, Xu-ri Huang, Aoqing TangAbstract:By means of polymer statistical theory, the sol fraction and the gelation condition of A f -A g type nonlinear free radical polymerization are obtained by introducing the probabilities with respect to initiation and chain addition. With Lagrange expansion theorem, the Equilibrium Number fraction distribution of A f -Ag type is obtained, and its invariant property is proved. Moreover, the evaluation of average polymer quantities for post-gel regime is simplified by this invariant property.
-
Curing theory of A f -A g type free radical polymerization (I)──Distribution function and its invariant property
Science China-chemistry, 1998Co-Authors: Haijun Wang, Ze-sheng Li, Zhong-yuan Lu, Xu-ri Huang, Aoqing TangAbstract:By means of polymer statistical theory, the sol fraction and the gelation condition of A f-A g type nonlinear free radical polymerization are obtained by introducing the probabilities with respect to initiation and chain addition. With Lagrange expansion theorem, the Equilibrium Number fraction distribution of A f-A g type is obtained, and its invariant property is proved. Moreover, the evaluation of average polymer quantities for post-gel regime is simplified by this invariant property.
-
Intrinsic symmetry of the AABb-type distribution
Macromolecular Theory and Simulations, 1994Co-Authors: Xing-cai Xiao, Ze-sheng Li, Auchin TangAbstract:By taking an A a B b -type polymerization as an example, an intrinsic symmetry of the Equilibrium Number fraction distribution of species is revealed. The symmetry shows that the distribution is invariant under transformation between the variables which describe the total system and the variables which describe the sol. It results that, when the polymer quantities for the pre-gel regime are given, the corresponding quantities for the post-gel regime can easily be obtained. As an illlustration, the k th radius of an A a B-type polymerization is discussed
-
On the intramolecular cyclization of Aa type crosslinking reaction
Journal of Macromolecular Science Part A, 1992Co-Authors: Auchin Tang, Ze-sheng LiAbstract:Abstract By taking into consideration of intramolecular cyclization, the Aa type crosslinking reaction is investigated to give the sol fraction for postgelation from which the Equilibrium Number fraction distribution is deduced. Furthermore, by means of differentiation technique, a recursion formula for evaluating the kth polymer moment is obtained.
J. Javier Sanchez-asin - One of the best experts on this subject based on the ideXlab platform.
-
Social Capital, Scale Economies of Skills and the Equilibrium Number of Entrepreneurs
SSRN Electronic Journal, 2015Co-Authors: Vincente Salas Fumás, J. Javier Sanchez-asinAbstract:This paper draws on occupational choice theory to explain that observed differences in shares of entrepreneurs as self-employed across countries, may respond to differences in social capital as a support of generalized trust. With a (incomplete) panel data from 63 countries, for a period of 25 years, we find that higher social capital is negatively associated with the share of self-employed who hire employees, and positively with the average Number of employees per employer. The results are consistent with the hypothesis that environments of high trust allow entrepreneurs, as employers, to implement more decentralized organization structures and to take advantage of the scale economies of skills in entrepreneurial decisions, leading to a market Equilibrium with fewer firms under the direction of high-skilled entrepreneurs. The paper also highlights the importance of treating the self-employed as a heterogeneous group of employers and solo self-employed in entrepreneurship research.
-
Social Capital and the Equilibrium Number of Entrepreneurs
SSRN Electronic Journal, 2011Co-Authors: Vicente Salas-fumás, J. Javier Sanchez-asinAbstract:Social capital is viewed either as a proprietary asset that serves private interests, including those of entrepreneurs, or as a collective asset that supports trust-based transactions saving on transaction costs both in markets and within the boundaries of firms, and benefiting society as a whole. This paper explains the relative specialization between entrepreneurs and market-governed exchanges as a result of the interaction between social capital that lowers transaction costs, and the scale economies of ability in managerial jobs (Lucas 1978). The main hypothesis formulated in the paper is that higher social capital will benefit the hierarchy relatively more than the market as a governance mechanism, and therefore in economies with higher social capital, the Equilibrium Number of entrepreneurs will be lower and their average span of control larger than in economies with lower social capital. The empirical evidence, with data from the Spanish Autonomous Communities, is consistent with this prediction.
D G Stephenson - One of the best experts on this subject based on the ideXlab platform.
-
colonization of the krakatau islands by land birds and the approach to an Equilibrium Number of species
Philosophical Transactions of the Royal Society B, 1990Co-Authors: I W B Thornton, R A Zann, D G StephensonAbstract:The colonization of the Krakataus by resident land birds is re-examined in view of two additional good data points, 1951 and 1984-86, which were not available to MacArthur & Wilson (1967) in their seminal work on island biogeography. The bird data for all years were carefully assessed with respect to the explicit criteria needed for the calculation of rates of extinction, immigration and turnover; these parameters are defined and calculated. Calculated from data from the two most recent surveys, the Equilibrium Number of species (S) for Rakata, the largest island, is from 48 to 56 and for the archipelago as a whole from 44 to 58; the ranges reflect alternative assessments of the records. By fitting a colonization equation to data from all surveys, S for the archipelago is estimated as 36 species, and by a procedure attempting to account for cryptoturnover, 38 species. These estimates compare with 30 (MacArthur & Wilson 1967) and 40-45 (Mayr 1965). Thirty-seven species were present during 1984-86. The establishment of the secondary forest and closure of the canopy had the greatest effect on colonization parameters of resident land birds since 1883. Immigration and turnover peaked in the period 1908-21 and fell sharply over the next decade, when, in contrast, extinctions reached a peak. The species that have colonized the Krakataus are mostly wide-ranging species that are found in both Java and Sumatra and have wide ecological tolerances. The earlier colonists were open country, generalist species, but since forest formation there was an increase in the proportion that are true forest species and more specialist feeders; more recent colonists have been aerial predators and insect feeders. Analysis of the colonization data suggests that the first resident land birds colonized the Krakataus one or two decades after the 1883 eruption. The newly emergent island, Anak Krakatau, has provided early seral habitats for species that have been lost from the other islands of the archipelago because of ecological succession and consequently the island provides an ecological refuge, postponing the extinction of birds that depend on these open habitats. Anak Krakatau's emergence and continued existence will reduce species turnover and delay the achievement of Equilibrium on the archipelago.
Matti Krusius - One of the best experts on this subject based on the ideXlab platform.
-
Equilibrium Number of quantized vortex lines in rotating3He-B
Czechoslovak Journal of Physics, 1996Co-Authors: Wen Xu, Bernard Plaçais, V. M. H. Ruutu, Matti KrusiusAbstract:A slow cool-down at constant rotation velocity Ω from the normal to the superfluid state is expected to give the Equilibrium state of vortex lines. We have checked this by counting the Number of vortex lines in3He-B using cw NMR. Our measurements with 0≤Ω≤0.28 rad/s confirm the expectation.
-
Quantized vortices at a moving A-B interface in superfluid3He
Physica B-condensed Matter, 1994Co-Authors: Erkki Thuneberg, Ü. Parts, Y. Kondo, J. S. Korhonen, Matti KrusiusAbstract:Abstract We have studied the B⇌A phase transitions in a rotating container. The initial state contains the Equilibrium Number of vortices, and after the A-B interface has traversed the container, the vortex state was studied using NMR. We find that the A-phase state resulting from a B→A transition contains the Equilibrium Number of continuous vortices. Possible explanations are discussed.
-
Vortex layer on the interface between the A and B phases in superfluid 3He.
Physical Review Letters, 1993Co-Authors: Ü. Parts, Matti Krusius, Y. Kondo, J. S. Korhonen, Erkki ThunebergAbstract:Using NMR techniques we monitor the structure and Number of vortices in a cylindrical container, rotating at constant angular velocity Ω, before and after the passage of the A-B interface. The initial A phase contains the Equilibrium Number of vortices. The final B phase is found to have a deficit of vortices which depends nonmonotonically on the measured time t AB of the A→B transition. We argue that a vortex layer is formed in front of the moving A-B interface. The measured vortex deficit can be understood by analyzing the stability of the layer
