86,569 research outputs found
Building stock dynamics and its impacts on materials and energy demand in China
China hosts a large amount of building stocks, which is nearly 50 billion square meters. Moreover, annual new construction is growing fast, representing half of the world's total. The trend is expected to continue through the year 2050. Impressive demand for new residential and commercial construction, relative shorter average building lifetime, and higher material intensities have driven massive domestic production of energy intensive building materials such as cement and steel. This paper developed a bottom-up building stock turnover model to project the growths, retrofits and retirements of China's residential and commercial building floor space from 2010 to 2050. It also applied typical material intensities and energy intensities to estimate building materials demand and energy consumed to produce these building materials. By conducting scenario analyses of building lifetime, it identified significant potentials of building materials and energy demand conservation. This study underscored the importance of addressing building material efficiency, improving building lifetime and quality, and promoting compact urban development to reduce energy and environment consequences in China
Dynamic charge inhomogenity in cuprate superconductors
The inelastic x-ray scattering spectrum for phonons of -symmetry
including the CuO bond-stretching phonon dispersion is analyzed by a Lorentz
fit in HgBaCuO and BiSrCuO, respectively, using
recently calculated phonon frequencies as input parameters. The resulting mode
frequencies of the fit are almost all in good agreement with the calculated
data. An exception is the second highest -branch compromising the
bond-stretching modes which disagrees in both compounds with the calculations.
This branch unlike the calculations shows an anomalous softening with a minimum
around the wavevector \vc{q}=\frac{2\pi}{a}(0.25, 0, 0). Such a disparity
with the calculated results, that are based on the assumption of an undisturbed
translation- and point group invariant electronic structure of the CuO plane,
indicates some {\it static} charge inhomogenities in the measured probes. Most
likely these will be charge stripes along the CuO bonds which have the
strongest coupling to certain longitudinal bond-stretching modes that in turn
selfconsistently induce corresponding {\it dynamic} charge inhomogenities. The
symmetry breaking by the mix of dynamic and static charge inhomogenities can
lead to a reconstruction of the Fermi surface into small pockets.Comment: 7 pages, 4 figure
“Open Markets” v. “Structured Bilateral Trades”: Results of Economic Modeling of Point-to-Point Source Water Quality Trading in the Non-Tidal Passaic River Basin
Environmental Economics and Policy,
Exploring the assortativity-clustering space of a network's degree sequence
Nowadays there is a multitude of measures designed to capture different
aspects of network structure. To be able to say if the structure of certain
network is expected or not, one needs a reference model (null model). One
frequently used null model is the ensemble of graphs with the same set of
degrees as the original network. In this paper we argue that this ensemble can
be more than just a null model -- it also carries information about the
original network and factors that affect its evolution. By mapping out this
ensemble in the space of some low-level network structure -- in our case those
measured by the assortativity and clustering coefficients -- one can for
example study how close to the valid region of the parameter space the observed
networks are. Such analysis suggests which quantities are actively optimized
during the evolution of the network. We use four very different biological
networks to exemplify our method. Among other things, we find that high
clustering might be a force in the evolution of protein interaction networks.
We also find that all four networks are conspicuously robust to both random
errors and targeted attacks
Doping evoluton of antiferromagnetic order and structural distortion in LaFeAsOF
We use neutron scattering to study the structural distortion and
antiferromagnetic (AFM) order in LaFeAsOF as the system is doped
with fluorine (F) to induce superconductivity. In the undoped state, LaFeAsO
exhibits a structural distortion, changing the symmetry from tetragonal (space
group ) to orthorhombic (space group ) at 155 K, and then
followed by an AFM order at 137 K. Doping the system with F gradually decreases
the structural distortion temperature, but suppresses the long range AFM order
before the emergence of superconductivity. Therefore, while superconductivity
in these Fe oxypnictides can survive in either the tetragonal or the
orthorhombic crystal structure, it competes directly with static AFM order.Comment: reference update
Intrinsic Percolative Superconductivity in Heavily Overdoped High Temperature Superconductors
Magnetic measurements on heavily overdoped ,
, and single crystals reveal
a new type magnetization hysteresis loops characterized by the vanishing of
usual central peak near zero field. Since this effect has been observed in
various systems with very different structural details, it reflects probably a
generic behavior for all high temperature superconductors. This easy
penetration of magnetic flux can be understood in the picture of percolative
superconductivity due to the inhomogeneous electronic state in heavily
overdoped regime.Comment: 4 pages, 5 figure
Field dependent anisotropy change in a supramolecular Mn(II)-[3x3] grid
The magnetic anisotropy of a novel Mn(II)-[3x3] grid complex was investigated
by means of high-field torque magnetometry. Torque vs. field curves at low
temperatures demonstrate a ground state with S > 0 and exhibit a torque step
due to a field induced level-crossing at B* \approx 7.5 T, accompanied by an
abrupt change of magnetic anisotropy from easy-axis to hard-axis type. These
observations are discussed in terms of a spin Hamiltonian formalism.Comment: 4 pages, 4 figures, to be published in Phys. Rev. Let
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