379 research outputs found
How to Increase Users' Social Commerce Engagement? A Technology Attractiveness Model
With the proliferation of social networking and electronic commerce, social commerce helps people engage in various forms of online social commercial activities through sharing their product or service knowledge and experiences. A better understanding of users' engagement in social commerce websites thus become increasingly important. Based on the attractiveness theory, this study proposes a research model that highlights the unique role of technology attractiveness, including task, social, and physical attractiveness, in promoting user involvement, which in turn affects social commerce engagement. Results demonstrate that users' perceptions of technology attractiveness are positively associated with their involvement with social commerce websites, and further stimulate engagement. In addition, website involvement partially and fully mediates the effects of social and physical attractiveness, respectively, on social commerce engagement. The limitations and implications of this study for research and practice are further discussed
How to Increase Users\u27 Social Commerce Engagement? A Technology Attractiveness Model
With the proliferation of social networking and electronic commerce, social commerce helps people engage in various forms of online social commercial activities through sharing their product or service knowledge and experiences. A better understanding of users\u27 engagement in social commerce websites thus become increasingly important. Based on the attractiveness theory, this study proposes a research model that highlights the unique role of technology attractiveness, including task, social, and physical attractiveness, in promoting user involvement, which in turn affects social commerce engagement. Results demonstrate that users\u27 perceptions of technology attractiveness are positively associated with their involvement with social commerce websites, and further stimulate engagement. In addition, website involvement partially and fully mediates the effects of social and physical attractiveness, respectively, on social commerce engagement. The limitations and implications of this study for research and practice are further discussed
Carbon Nanotubes Synthesized in Channels of Alpo4-5 Single Crystals : First X-Ray Scattering Investigations
Following the synthesis of aligned single-wall carbon nanotubes in the
channels of AlPO4-5 zeolite single crystals, we present the first X-ray
diffraction and diffuse scattering results. They can be analysed in terms of a
partial filling of the zeolite channels by nanotubes with diameter around 4A.
The possible selection of only one type of nanotube during the synthesis, due
to the constraints imposed by the zeolite host, is discussed.Comment: to appear in Solid State Com
Superparamagnetic behavior in Fe ultrathin films on GaN(0001)
In this paper, growth, structural and magnetic properties of ultrathin Fe grown on GaN(OOOl) by molecular beam epitaxy. The films and their surfaces were monitored by in-situ reflection high energy electron diffraction (RHEED) and a crystal thickness monitor. The magnetic properties of the samples were determined by a superconducting quantum interference device (SQUID) magnetometer. Superparamagnetism (SPM) of the ultrathin Fe can be activated at the ambient temperature.the hysteresis loop of an as-deposited 5 ML Fe(llO) film on GaN(0001) taken at RT and reveals that the loop on one hand has an unsaturated magnetization and on the other hand possesses tiny but noticeable Mr and Hc. These two characteristics as a whole imply a coexistence of SPM and weak FM in the ultrathin film. In order to gain further insight into this mixed magnetic state, temperature dependence of the magnetization M(T) in the form of field cooling (FC) and zero field cooling (ZFC) curves of the 5 ML sample was measured by SQUID in a T range between 5 and 300 K
Effects of bearing clearance on the chatter stability of milling process
In the present study, the influences of the bearing clearance, which is a common fault for machines, to the chatter stability of milling process are examined by using numerical simulation method. The results reveal that the presence of bearing clearance could make the milling process easier to enter the status of chatter instability and can shift the chatter frequency. In addition, the spectra analysis to vibration signals obtained under the instable milling processes show that the presence of bearing clearance could introduce more frequency components to the vibration responses but, however, under both the stable and instable milling processes, the generated frequency components will not violate the ideal spectra structures of the vibration responses of the milling process, which are usually characterized by the tooth passing frequency and its associated higher harmonics for the stable milling process and by the complex coupling of the tooth passing frequency and the chatter frequency for the instable milling process. This implies that, even under the case with bearing clearance fault, the stability of the milling process can still be determined by viewing the frequency spectra of the vibration responses. Moreover, the phenomena of the chatter frequency shift and the generation of more components provide potential ways to detect the bearing clearance in machines. (C) 2010 Elsevier Ltd. All rights reserved
Interacting Three Fluid System and Thermodynamics of the Universe Bounded by the Event Horizon
The work deals with the thermodynamics of the universe bounded by the event
horizon. The matter in the universe has three constituents namely dark energy,
dark matter and radiation in nature and interaction between then is assumed.
The variation of entropy of the surface of the horizon is obtained from unified
first law while matter entropy variation is calculated from the Gibbss' law.
Finally, validity of the generalized second law of thermodynamics is examined
and conclusions are written point wise.Comment: 7 page
Interacting Agegraphic Dark Energy
A new dark energy model, named "agegraphic dark energy", has been proposed
recently, based on the so-called K\'{a}rolyh\'{a}zy uncertainty relation, which
arises from quantum mechanics together with general relativity. In this note,
we extend the original agegraphic dark energy model by including the
interaction between agegraphic dark energy and pressureless (dark) matter. In
the interacting agegraphic dark energy model, there are many interesting
features different from the original agegraphic dark energy model and
holographic dark energy model. The similarity and difference between agegraphic
dark energy and holographic dark energy are also discussed.Comment: 10 pages, 5 figures, revtex4; v2: references added; v3: accepted by
Eur. Phys. J. C; v4: published versio
Parametrization of Born-Infeld Type Phantom Dark Energy Model
Applying the parametrization of dark energy density, we can construct
directly independent-model potentials. In Born-Infeld type phantom dark energy
model, we consider four special parametrization equation of state parameter.
The evolutive behavior of dark energy density with respect to red-shift ,
potentials with respect to and are shown mathematically. Moreover,
we investigate the effect of parameter upon the evolution of the
constructed potential with respect to . These results show that the
evolutive behavior of constructed Born-Infeld type dark energy model is quite
different from those of the other models.Comment: 5 pages, 4 figures, Accepted for publication in Astrophysics & Space
Scienc
Asymptotic behavior of w in general quintom model
For the quintom models with arbitrary potential , the
asymptotic value of equation of state parameter w is obtained by a new method.
In this method, w of stable attractors are calculated by using the ratio (d ln
V)/(d ln a) in asymptotic region. All the known results, have been obtained by
other methods, are reproduced by this method as specific examples.Comment: 8 pages, one example is added, accepted for publication in Gen. Rel.
Gra
Cosmological Constraints on the Sign-Changeable Interactions
Recently, Cai and Su [Phys. Rev. D {\bf 81}, 103514 (2010)] found that the
sign of interaction in the dark sector changed in the approximate redshift
range of 0.45\,\lsim\, z\,\lsim\, 0.9, by using a model-independent method to
deal with the observational data. In fact, this result raises a remarkable
problem, since most of the familiar interactions cannot change their signs in
the whole cosmic history. Motivated by the work of Cai and Su, we have proposed
a new type of interaction in a previous work [H. Wei, Nucl. Phys. B {\bf 845},
381 (2011)]. The key ingredient is the deceleration parameter in the
interaction , and hence the interaction can change its sign when our
universe changes from deceleration () to acceleration (). In the
present work, we consider the cosmological constraints on this new type of
sign-changeable interactions, by using the latest observational data. We find
that the cosmological constraints on the model parameters are fairly tight. In
particular, the key parameter can be constrained to a narrow range.Comment: 15 pages, 1 table, 8 figures, revtex4; v2: published versio
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