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Scenarios of energy efficiency and CO2 emissions reduction potential in the buildings sector in China to year 2050
As China’s rapid urbanization continues and urban dwellers become more affluent, energy use in buildings is expected to grow. To understand how this growth can be slowed, we explore four scenarios for Chinese buildings, ranging from a high-energy-demand scenario with no new energy policies to lowest energy demand under a techno-economic-potential scenario that assumes full deployment of cost-effective efficient and renewable technologies by 2050. We show that, in the high energy demand scenario, building energy demand has an average annual growth rate of about 2.8%, with slower growth rates in the other three scenarios. In all scenarios, CO2 emissions grow slower than energy, with building CO2 peaking around 2045 in the high energy demand scenario, and as early as 2030 in the techno-economic-potential scenario. We show that although various technological solutions, systems and practices can be very effective in minimizing building energy use, rigorous policies are needed to overcome multiple implementation barriers
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On the Elevated Temperature Thermal Stability of Nanoscale Mn-Ni-Si Precipitates Formed at Lower Temperature in Highly Irradiated Reactor Pressure Vessel Steels.
Atom probe tomography (APT) and scanning transmission electron microscopy (STEM) techniques were used to probe the long-time thermal stability of nm-scale Mn-Ni-Si precipitates (MNSPs) formed in intermediate and high Ni reactor pressure vessel steels under high fluence neutron irradiation at ≈320 °C. Post irradiation annealing (PIA) at 425 °C for up to 57 weeks was used to determine if the MNSPs are: (a) non-equilibrium solute clusters formed and sustained by radiation induced segregation (RIS); or, (b) equilibrium G or Γ2 phases, that precipitate at accelerated rates due to radiation enhanced diffusion (RED). Note the latter is consistent with both thermodynamic models and x-ray diffraction (XRD) measurements. Both the experimental and an independently calibrated cluster dynamics (CD) model results show that the stability of the MNSPs is very sensitive to the alloy Ni and, to a lesser extent, Mn content. Thus, a small fraction of the largest MNSPs in the high Ni steel persist, and begin to coarsen at long times. These results suggest that the MNSPs remain a stable phase, even at 105 °C higher than they formed at, thus are most certainly equilibrium phases at much lower service relevant temperatures of ≈290 °C
Strain accommodation through facet matching in LaSrCuO/NdCeCuO ramp-edge junctions
Scanning nano-focused X-ray diffraction (nXRD) and high-angle annular
dark-field scanning transmission electron microscopy (HAADF-STEM) are used to
investigate the crystal structure of ramp-edge junctions between
superconducting electron-doped NdCeCuO
and superconducting hole-doped LaSrCuO
thin films, the latter being the top layer. On the ramp, a new growth mode of
LaSrCuO with a 3.3 degree tilt of the
c-axis is found. We explain the tilt by developing a strain accommodation model
that relies on facet matching, dictated by the ramp angle, indicating that a
coherent domain boundary is formed at the interface. The possible implications
of this growth mode for the creation of artificial domains in morphotropic
materials are discussed.Comment: 5 pages, 4 figures & 3 pages supplemental information with 2 figures.
Copyright (2015) American Institute of Physics. This article may be
downloaded for personal use only. Any other use requires prior permission of
the author and the American Institute of Physics. The following article
appeared in APL Mat. 3, 086101 (2015) and may be found at
http://dx.doi.org/10.1063/1.492779
Sensitivity of Ag/Al Interface Specific Resistances to Interfacial Intermixing
We have measured an Ag/Al interface specific resistance, 2AR(Ag/Al)(111) =
1.4 fOhm-m^2, that is twice that predicted for a perfect interface, 50% larger
than for a 2 ML 50%-50% alloy, and even larger than our newly predicted 1.3
fOhmm^2 for a 4 ML 50%-50% alloy. Such a large value of 2ARAg/Al(111) confirms
a predicted sensitivity to interfacial disorder and suggests an interface
greater than or equal to 4 ML thick. From our calculations, a predicted
anisotropy ratio, 2AR(Ag/Al)(001)/2AR(Ag/Al)(111), of more then 4 for a perfect
interface, should be reduced to less than 2 for a 4 ML interface, making it
harder to detect any such anisotropy.Comment: 3 pages, 2 figures, 1 table. In Press: Journal of Applied Physic
Comparative experimental study of local mixing of active and passive scalars in turbulent thermal convection
We investigate experimentally the statistical properties of active and
passive scalar fields in turbulent Rayleigh-B\'{e}nard convection in water, at
. Both the local concentration of fluorescence dye and the local
temperature are measured near the sidewall of a rectangular cell. It is found
that, although they are advected by the same turbulent flow, the two scalars
distribute differently. This difference is twofold, i.e. both the quantities
themselves and their small-scale increments have different distributions. Our
results show that there is a certain buoyant scale based on time domain, i.e.
the Bolgiano time scale , above which buoyancy effects are significant.
Above , temperature is active and is found to be more intermittent than
concentration, which is passive. This suggests that the active scalar possesses
a higher level of intermittency in turbulent thermal convection. It is further
found that the mixing of both scalar fields are isotropic for scales larger
than even though buoyancy acts on the fluid in the vertical direction.
Below , temperature is passive and is found to be more anisotropic than
concentration. But this higher degree of anisotropy is attributed to the higher
diffusivity of temperature over that of concentration. From the simultaneous
measurements of temperature and concentration, it is shown that two scalars
have similar autocorrelation functions and there is a strong and positive
correlation between them.Comment: 13 pages and 12 figure
Ground-state properties of the two-site Hubbard-Holstein model: an exact solution
We revisit the two-site Hubbard-Holstein model by using extended phonon
coherent states. The nontrivial singlet bipolaron is studied exactly in the
whole coupling regime. The ground-state (GS) energy and the double occupancy
probability are calculated. The linear entropy is exploited successfully to
quantify bipartite entanglement between electrons and their environment
phonons, displaying a maximum entanglement of the singlet-bipolaron in strong
coupling regime. A dramatic drop in the crossover regime is observed in the GS
fidelity and its susceptibility. The bipolaron properties is also characterized
classically by correlation functions. It is found that the crossover from a
two-site to single-site bipolaron is more abrupt and shifts to a larger
electron-phonon coupling strength as electron-electron Coulomb repulsion
increases.Comment: 6 pages, 6 figure
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