8,884 research outputs found
Studies on the evolution of alkali silicate in a simulated alkali-silica reaction system
In this study, the interaction between the reactive silica present in aggregates and the alkalis and
hydroxyls present in the pore solution of cement paste is simulated in a chemical model system and
investigated experimentally. Various properties of the solid and liquid phases are investigated. The
results show that the nano and micro structure and properties of the formed alkali silicate change
significantly during this process
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Atomic and nano-scale characterization of a 50-year-old hydrated C3S paste
This paper investigates the atomic and nano-scale structures of a 50-year-old hydrated alite paste. Imaged by TEM, the outer product C-S-H fibers are composed of particles that are 1.5-2 nm thick and several tens of nanometers long. 29Si NMR shows 47.9% Q1 and 52.1% Q2, with a mean SiO4 tetrahedron chain length (MCL) of 4.18, indicating a limited degree of polymerization after 50 years' hydration. A Scanning Transmission X-ray Microscopy (STXM) study was conducted on this late-age paste and a 1.5 year old hydrated C3S solution. Near Edge X-ray Absorption Fine Structure (NEXAFS) at Ca L3,2-edge indicates that Ca2 + in C-S-H is in an irregular symmetric coordination, which agrees more with the atomic structure of tobermorite than that of jennite. At Si K-edge, multi-scattering phenomenon is sensitive to the degree of polymerization, which has the potential to unveil the structure of the SiO44 - tetrahedron chain
Kashaev's invariant and the volume of a hyperbolic knot after Y. Yokota
I follow Y. Yokota to explain how to obtain a tetrahedron decomposition of
the complement of a hyperbolic knot and compare it with the asymptotic behavior
of Kashaev's link invariant using the figure-eight knot as an example.Comment: 21 pages, 21 figures, submitted to the Proceedings of "Physics and
Combinatorics" Workshop, Nagoya 199
Tetrahedron Equation and Quantum R Matrices for Spin Representations of B^{(1)}_n, D^{(1)}_n and D^{(2)}_{n+1}
It is known that a solution of the tetrahedron equation generates infinitely
many solutions of the Yang-Baxter equation via suitable reductions. In this
paper this scheme is applied to an oscillator solution of the tetrahedron
equation involving bosons and fermions by using special 3d boundary conditions.
The resulting solutions of the Yang-Baxter equation are identified with the
quantum R matrices for the spin representations of B^{(1)}_n, D^{(1)}_n and
D^{(2)}_{n+1}.Comment: 17 pages, 7 figures, minor misprint correcte
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