171,431 research outputs found
Effect of distribution of stickers along backbone on temperature-dependent structural properties in associative polymer solutions
Effect of distribution of stickers along the backbone on structural
properties in associating polymer solutions is studied using self-consistent
field lattice model. Only two inhomogeneous morphologies, i.e.,
microfluctuation homogenous (MFH) and micelle morphologies, are observed. If
the system is cooled, the solvent content within the aggregates decreases. When
the spacing of stickers along the backbone is increased the
temperature-dependent range of aggregation in MFH morphology and half-width of
specific heat peak for homogenous solutions-MFH transition increase, and the
symmetry of the peak decreases. However, with increasing spacing of stickers,
the above three corresponding quantities related to micelles behave
differently. It is demonstrated that the broad nature of the observed
transitions can be ascribed to the structural changes which accompany the
replacement of solvents in aggregates by polymer, which is consistent with the
experimental conclusion. It is found that different effect of spacing of
stickers on the two transitions can be interpreted in terms of intrachain and
interchain associations.Comment: 10 pages, 4 figures. arXiv admin note: text overlap with
arXiv:1202.459
Spectral Theory of Time Dispersive and Dissipative Systems
We study linear time dispersive and dissipative systems. Very often such
systems are not conservative and the standard spectral theory can not be
applied. We develop a mathematically consistent framework allowing (i) to
constructively determine if a given time dispersive system can be extended to a
conservative one; (ii) to construct that very conservative system -- which we
show is essentially unique. We illustrate the method by applying it to the
spectral analysis of time dispersive dielectrics and the damped oscillator with
retarded friction. In particular, we obtain a conservative extension of the
Maxwell equations which is equivalent to the original Maxwell equations for a
dispersive and lossy dielectric medium.Comment: LaTeX, 57 Pages, incorporated revisions corresponding with published
versio
Measurement and Analysis of Multiband Bistatic and Monostatic Radar Signatures of Wind Turbines
This paper presents the results of recent measurements taken with two radar systems to measure the simultaneous monostatic and bistatic signature of wind turbines, at S-band and X-band. Coherent monostatic and bistatic data was collected with the University College London (UCL) NetRAD 2.4 GHz radar, and the Cranfield University CW radar operating at X-band. This initial analysis shows the bistatic Doppler signature of wind turbines and informs on the key differences seen at modest bistatic angles. Polarimetric variations are also analysed via data gathered using co-polarised VV and HH and cross-polarised VH components
Parton Distributions at Hadronization from Bulk Dense Matter Produced at RHIC
We present an analysis of , , and spectra from
Au+Au collisions at GeV in terms of distributions of
effective constituent quarks at hadronization. Consistency in quark ratios
derived from various hadron spectra provides clear evidence for hadron
formation dynamics as suggested by quark coalescence or recombination models.
We argue that the constituent quark distribution reflects properties of the
effective partonic degrees of freedom at hadronization. Experimental data
indicate that strange quarks have a transverse momentum distribution flatter
than that of up/down quarks consistent with hydrodynamic expansion in partonic
phase prior to hadronization. After the AMPT model is tuned to reproduce the
strange and up/down quark distributions, the model can describe the measured
spectra of hyperons and mesons very well where hadrons are formed
through dynamical coalescence.Comment: 5 pages, 3 figures, two more paragraph added to address the referee's
comment, figure updated to include the KET scale. Accepted version to appear
in Phys. Rev.
Dynamic Transitions for Quasilinear Systems and Cahn-Hilliard equation with Onsager mobility
The main objectives of this article are two-fold. First, we study the effect
of the nonlinear Onsager mobility on the phase transition and on the
well-posedness of the Cahn-Hilliard equation modeling a binary system. It is
shown in particular that the dynamic transition is essentially independent of
the nonlinearity of the Onsager mobility. However, the nonlinearity of the
mobility does cause substantial technical difficulty for the well-posedness and
for carrying out the dynamic transition analysis. For this reason, as a second
objective, we introduce a systematic approach to deal with phase transition
problems modeled by quasilinear partial differential equation, following the
ideas of the dynamic transition theory developed recently by Ma and Wang
Extended Hylleraas three-electron integral
A closed form expression for the three-electron Hylleraas integral involving
the inverse quadratic power of one inter-particle coordinate is obtained, and
recursion relations are derived for positive powers of other coordinates. This
result is suited for high precision calculations of relativistic effects in
lithium and light lithium-like ions.Comment: Submited to Phys. Rev.
Preserving Our Collective Memory: The Case of HK Magazine
Founded in 1991, HK Magazine was one of the major English-language publications on local affairs, social issues and entertainment listings published weekly in Hong Kong for a quarter of a century. Apart from providing local entertainment information, it also witnessed the rapid social and political changes of Hong Kong when Britain handed over sovereignty of Hong Kong to China in 1997. In July 2013, HK Magazine was sold to the South China Morning Post (SCMP) Group which was subsequently purchased by Alibaba Group in December 2015. However, the SCMP Group announced on 28 September 2016 that the magazine's final issue would be released on 7 October 2016. The closure of the magazine was viewed by many as the loss of a “fun, independent and free-thinking' publication. In response to the huge reaction from the community, the SCMP Group agreed that the content of HK Magazine would be migrated to the SCMP website before the HK Magazine website was removed. It was however revealed that the SCMP website did not preserve the full archive of HK Magazine as promised. A public appeal was launched to help preserve the collective memory of Hong Kong by archiving the back issues of the magazine. Apart from reviewing the discussion arising from the close down of HK Magazine, this paper also addresses the critical role of the library in long term preserving HK Magazine on one hand and providing access to its digital content on the other
- …