7,331 research outputs found
(E)-2-(4-Methoxyphenyl)-N-(2-pyridyl)-3-(2-pyridylamino)acrylamide
In the title compound, C20H18N4O2, the aminoacrylamide group makes a dihedral angles of 4.0 (1)° with the amino-bound pyridyl ring and 15.66 (12)° with the amide-bound pyridyl ring. The dihedral angle between the aminoacrylamide group and the pendant 4-methoxyphenyl group is 71.22 (9)°. In the crystal structure, N—H⋯N hydrogen bonds and C—H⋯O and C—H⋯N interactions help to establish the packing. Intramolecular C—H⋯O and C—H⋯(N,O) contacts also occur
Controllable Goos-H\"{a}nchen shifts and spin beam splitter for ballistic electrons in a parabolic quantum well under a uniform magnetic field
The quantum Goos-H\"{a}nchen shift for ballistic electrons is investigated in
a parabolic potential well under a uniform vertical magnetic field. It is found
that the Goos-H\"{a}nchen shift can be negative as well as positive, and
becomes zero at transmission resonances. The beam shift depends not only on the
incident energy and incidence angle, but also on the magnetic field and Landau
quantum number. Based on these phenomena, we propose an alternative way to
realize the spin beam splitter in the proposed spintronic device, which can
completely separate spin-up and spin-down electron beams by negative and
positive Goos-H\"{a}nchen shifts.Comment: 6 pages, 6 figure
Cascading failures in coupled networks with both inner-dependency and inter-dependency links
We study the percolation in coupled networks with both inner-dependency and
inter-dependency links, where the inner- and inter-dependency links represent
the dependencies between nodes in the same or different networks, respectively.
We find that when most of dependency links are inner- or inter-ones, the
coupled networks system is fragile and makes a discontinuous percolation
transition. However, when the numbers of two types of dependency links are
close to each other, the system is robust and makes a continuous percolation
transition. This indicates that the high density of dependency links could not
always lead to a discontinuous percolation transition as the previous studies.
More interestingly, although the robustness of the system can be optimized by
adjusting the ratio of the two types of dependency links, there exists a
critical average degree of the networks for coupled random networks, below
which the crossover of the two types of percolation transitions disappears, and
the system will always demonstrate a discontinuous percolation transition. We
also develop an approach to analyze this model, which is agreement with the
simulation results well.Comment: 9 pages, 4 figure
Neutron Density Distributions of Neutron-Rich Nuclei Studied with the Isobaric Yield Ratio Difference
The isobaric yield ratio difference (IBD) between two reactions of similar
experimental setups is found to be sensitive to nuclear density differences
between projectiles. In this article, the IBD probe is used to study the
density variation in neutron-rich Ca. By adjusting diffuseness in the
neutron density distribution, three different neutron density distributions of
Ca are obtained. The yields of fragments in the 80 MeV Ca
+ C reactions are calculated by using a modified statistical
abrasion-ablation model. It is found that the IBD results obtained from the
prefragments are sensitive to the density distribution of the projectile, while
the IBD results from the final fragments are less sensitive to the density
distribution of the projectile.Comment: 3 figure
Parameter-tuning Networks: Experiments and Active Walk Model
The tuning process of a large apparatus of many components could be
represented and quantified by constructing parameter-tuning networks. The
experimental tuning of the ion source of the neutral beam injector of HT-7
Tokamak is presented as an example. Stretched-exponential cumulative degree
distributions are found in the parameter-tuning networks. An active walk model
with eight walkers is constructed. Each active walker is a particle moving with
friction in an energy landscape; the landscape is modified by the collective
action of all the walkers. Numerical simulations show that the parameter-tuning
networks generated by the model also give stretched exponential functions, in
good agreement with experiments. Our methods provide a new way and a new
insight to understand the action of humans in the parameter-tuning of
experimental processes, is helpful for experimental research and other
optimization problems.Comment: 4 pages, 5 figure
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