47,917 research outputs found
Effective potentials for atom-atom interaction at low temperatures
We discuss the concept and design of effective atom-atom potentials that
accurately describe any physical processes involving only states around the
threshold. The existence of such potentials gives hope to a quantitative, and
systematic, understanding of quantum few-atom and quantum many-atom systems at
relatively low temperatures.Comment: 4 pages, 4 figure
Study on laser welding of dual phase steel
In this paper, Neodymium-doped Yttrium Aluminum Garnet crystal laser welding machine is used to study the laser welding process of dual phase steel. The electric current, pulse width and frequency are selected as variables for welding, and the maximum force of weldment under different parameters is detected by tensile testing machine. Through the analysis of the experimental results, find out the influence of different parameters on the welding quality, select the best welding parameters. The analysis shows that the current has the most significant effect on the welding quality, followed by the frequency, and the pulse width has almost no effect
Efficient electronic entanglement concentration assisted with single mobile electron
We present an efficient entanglement concentration protocol (ECP) for mobile
electrons with charge detection. This protocol is quite different from other
ECPs for one can obtain a maximally entangled pair from a pair of
less-entangled state and a single mobile electron with a certain probability.
With the help of charge detection, it can be repeated to reach a higher success
probability. It also does not need to know the coefficient of the original
less-entangled states. All these advantages may make this protocol useful in
current distributed quantum information processing.Comment: 6pages, 3figure
Evolution of Conversations in the Age of Email Overload
Email is a ubiquitous communications tool in the workplace and plays an
important role in social interactions. Previous studies of email were largely
based on surveys and limited to relatively small populations of email users
within organizations. In this paper, we report results of a large-scale study
of more than 2 million users exchanging 16 billion emails over several months.
We quantitatively characterize the replying behavior in conversations within
pairs of users. In particular, we study the time it takes the user to reply to
a received message and the length of the reply sent. We consider a variety of
factors that affect the reply time and length, such as the stage of the
conversation, user demographics, and use of portable devices. In addition, we
study how increasing load affects emailing behavior. We find that as users
receive more email messages in a day, they reply to a smaller fraction of them,
using shorter replies. However, their responsiveness remains intact, and they
may even reply to emails faster. Finally, we predict the time to reply, length
of reply, and whether the reply ends a conversation. We demonstrate
considerable improvement over the baseline in all three prediction tasks,
showing the significant role that the factors that we uncover play, in
determining replying behavior. We rank these factors based on their predictive
power. Our findings have important implications for understanding human
behavior and designing better email management applications for tasks like
ranking unread emails.Comment: 11 page, 24th International World Wide Web Conferenc
On the role of selective nucleation and growth to recrystallization texture development in a Mg-Gd-Zn alloy
One of the main material properties altered by rare earth additions in
magnesium alloys is texture, which can be specifically adjusted to enhance
ductility and formability. The current study aims at illuminating the texture
selection process in a Mg-0.073at%Gd-0.165at%Zn alloy by investigating
recrystallization nucleation and early nucleus growth during static
recrystallization. An as-cast sample of the investigated alloy was deformed in
uniaxial compression at 200{\deg}C till 40% strain and was then cut into two
halves for subsequent microstructure characterization via ex-situ and quasi
in-situ EBSD investigations. In order to gain insights into the evolution of
texture during recrystallization, the contributions from dynamic and static
recrystallization were initially separated and the origin of the non-basal
orientation of recrystallization nuclei was traced back to several potential
nucleation sites within the deformed matrix. Considering the significant role
of double-twin band recrystallization in determining the recrystallization
texture, this type of recrystallization nucleation was further investigated via
quasi-in-situ EBSD on a deformed sample, annealed at 400{\deg} for different
annealing times. With progressive annealing a noticeable trend was observed, in
which the basal nuclei gradually diminished and eventually vanished from the
annealed microstructure. In contrast, the off-basal nuclei exhibited continuous
growth, ultimately becoming the dominant contributors to the recrystallization
texture. The study therefore emphasizes the importance of particular nucleation
sites that generate favorably oriented off-basal nuclei, which over the course
of recrystallization outcompete the neighboring basal-oriented nuclei in terms
of growth, and thereby dominate the recrystallization texture
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