45,913 research outputs found
A new conducting polymer with exceptional visible-light photocatalytic activity derived from varbituric acid polycondensation
Abstract A novel covalent, metal-free, photocatalytic material is prepared by thermal polymerization of barbituric acid (BA). The structure of the photocatalyst is analyzed by using scanning electron microscopy, X-ray diffraction, and infrared, UV?visible, and 1H solution and 13C solid-state NMR spectroscopy. The photodegradation efficiency of BA thermally polymerized at different temperatures is tested by photocatalytic degradation of aquatic rhodamine B (RhB) dye under visible-light irradiation. It is shown that heating BA at an optimized temperature of 300 °C, that is, still in the range that polymer-like polycondensation takes place, results in a photocatalyst that can remove RhB with 96% photodegradation efficiency after 70 min exposure to visible light. The polycondensation reaction of BA is identified to process through precipitation of trimer units as primary building blocks. Reference experiments such as addition of scavengers and saturation with oxygen are studied to understand the photodegradation process. It is shown that the presence of triethanolamine, and excess of oxygen and p-benzoquinone in the solution of RhB and photocatalyst (BA300) is not beneficial, but decreases the photodegradation efficiency
Fake View Analytics in Online Video Services
Online video-on-demand(VoD) services invariably maintain a view count for
each video they serve, and it has become an important currency for various
stakeholders, from viewers, to content owners, advertizers, and the online
service providers themselves. There is often significant financial incentive to
use a robot (or a botnet) to artificially create fake views. How can we detect
the fake views? Can we detect them (and stop them) using online algorithms as
they occur? What is the extent of fake views with current VoD service
providers? These are the questions we study in the paper. We develop some
algorithms and show that they are quite effective for this problem.Comment: 25 pages, 15 figure
Competing Ground States in Triple-layered Sr4Ru3O10: Verging on Itinerant Ferromagnetism with Critical Fluctuations
Sr4Ru3O10 is characterized by a sharp metamagnetic transition and
ferromagnetic behavior occurring within the basal plane and along the c-axis,
respectively. Resistivity at magnetic field, B, exhibits low-frequency quantum
oscillations when B||c-axis and large magnetoresistivity accompanied by
critical fluctuations driven by the metamagnetism when B^c-axis. The complex
behavior evidenced in resistivity, magnetization and specific heat presented is
not characteristic of any obvious ground states, and points to an exotic state
that shows a delicate balance between fluctuations and order.Comment: 18 pages, 4 figure
Elite Christianity and Spiritual Nationalism
This paper explores the intersection of spiritual renewal and grassroots nationalism within contemporary Chinese Christianity through the case of an emerging group of Christian businessmen who have spearheaded the growth of independent churches in the coastal Wenzhou area, called "boss Christians." Prompted by their success in the new entrepreneurial world, these elite male Christians strive to gain spiritual prestige and moral superiority in the Chinese church by employing a spiritual narrative of their post-Mao economic success and by articulating and spreading a new vision that they call "God's China vision." In active response to the Chinese state's nationalist discourse of modernity, they are convinced that China will rise not only in the economic sphere but also in the spiritual realm and will transform itself from a missionary-receiving country to a missionary-sending one. The paper links this grass-roots project of spiritual nationalism to a redemptive process in which elite Chinese Christians seek to address and overcome victimization and suffering inflicted by secular state modernity. It concludes that post-Mao Christian development has come to be closely connected to national memories and nationalist imagination, countering the party-state's insistence on secular nationalism.postprin
Renegotiating Locality and Morality in a Chinese Religious Diaspora: Wenzhou Christian Merchants in Paris, France
postprin
Book Reviews
The Variational Auto-Encoder (VAE) is one of the most used unsupervised
machine learning models. But although the default choice of a Gaussian
distribution for both the prior and posterior represents a mathematically
convenient distribution often leading to competitive results, we show that this
parameterization fails to model data with a latent hyperspherical structure. To
address this issue we propose using a von Mises-Fisher (vMF) distribution
instead, leading to a hyperspherical latent space. Through a series of
experiments we show how such a hyperspherical VAE, or -VAE, is
more suitable for capturing data with a hyperspherical latent structure, while
outperforming a normal, -VAE, in low dimensions on other data
types.Comment: GitHub repository: http://github.com/nicola-decao/s-vae-tf, Blogpost:
https://nicola-decao.github.io/s-va
Universality and correlations in individuals wandering through an online extremist space
The 'out of the blue' nature of recent terror attacks and the diversity of
apparent motives, highlight the importance of understanding the online
trajectories that individuals follow prior to developing high levels of
extremist support. Here we show that the physics of stochastic walks, with and
without temporal correlation, provides a unifying description of these online
trajectories. Our unique dataset comprising all users of a global social media
site, reveals universal characteristics in individuals' online lifetimes. Our
accompanying theory generates analytical and numerical solutions that describe
the characteristics shown by individuals that go on to develop high levels of
extremist support, and those that do not. The existence of these temporal and
also many-body correlations suggests that existing physics machinery can be
used to quantify and perhaps mitigate the risk of future events
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