50 research outputs found
Opportunistic Wireless Control Over State-Dependent Fading Channels
The heterogeneous system consisting of the wireless control system (WCS) and
mobile agent system (MAS) is ubiquitous in Industrial Internet of Things (IIoT)
systems. Within this system, the positions of mobile agents may lead to shadow
fading on the wireless channel that the WCS is controlled over and can
significantly compromise the WCS's performance. This paper focuses on the
controller design for the MAS to ensure the performance of WCS in the presence
of WCS and MAS coupling. Firstly, the constrained finite field network (FFN)
with profile-dependent switching topology is adopted to proceed the operational
control for the MAS. By virtue of the algebraic state space representation
(ASSR) method, an equivalent form is obtained for the WCS and MAS coupling. A
necessary and sufficient condition in terms of constrained set stabilization is
then established to ensure the Lyapunov-like performance with expected decay
rate. Finally, a graphical method together with the breath-first searching is
provided to design state feedback controllers for the MAS. With this method, it
is easy to check the constrained set stabilization of MAS and to ensure the
performance requirements of WCS in the presence of WCS and MAS coupling. The
study of an illustrative example shows the effectiveness of the proposed
method
Large-gap quantum spin Hall insulators in tin films
The search of large-gap quantum spin Hall (QSH) insulators and effective
approaches to tune QSH states is important for both fundamental and practical
interests. Based on first-principles calculations we find two-dimensional tin
films are QSH insulators with sizable bulk gaps of 0.3 eV, sufficiently large
for practical applications at room temperature. These QSH states can be
effectively tuned by chemical functionalization and by external strain. The
mechanism for the QSH effect in this system is band inversion at the \Gamma
point, similar to the case of HgTe quantum well. With surface doping of
magnetic elements, the quantum anomalous Hall effect could also be realized
Intertwined Dirac cones induced by anisotropic coupling in antiferromagnetic topological insulator
Antiferromagnetic topological insulators (AFM TIs), which host magnetically
gapped Dirac-cone surface states and exhibit many exotic physical phenomena,
have attracted great attention. The coupling between the top and bottom surface
states becomes significant and plays a crucial role in its low-energy physics,
as the thickness of an AFM TI film decreases. Here, we find that the coupled
surface states can be intertwined to give birth to a set of brand new
Dirac cones, dubbed \emph{intertwined Dirac cones}, through the anisotropic
coupling due to the -fold crystalline rotation symmetry () in the presence of an out-of-plane electric field. Interestingly, we
also find that the warping effect further drives the intertwined Dirac-cone
state into a quantum anomalous Hall phase with a high Chern number ().
Then, we demonstrate the emergent six intertwined Dirac cones and the
corresponding Chern insulating phase with a high Chern number () in
MnBiTe(BiTe)MnBiTe heterostructures
through first-principles calculations. This work discovers a new intertwined
Dirac-cone state in AFM TI thin films and also reveals a new mechanism for
designing the quantum anomalous Hall state with a high Chern number.Comment: 7 pages, 4 figures+supplemental material
Floquet engineering of black phosphorus upon below-gap pumping
Time-periodic light field can dress the electronic states and lead to
light-induced emergent properties in quantum materials. While below-gap pumping
is regarded favorable for Floquet engineering, so far direct experimental
evidence of momentum-resolved band renormalization still remains missing. Here,
we report experimental evidence of light-induced band renormalization in black
phosphorus by pumping at photon energy of 160 meV which is far below the band
gap, and the distinction between below-gap pumping and near-resonance pumping
is revealed. Our work demonstrates light-induced band engineering upon
below-gap pumping, and provides insights for extending Floquet engineering to
more quantum materials
Developmental clock and mechanism of de novo polarization of the mouse embryo.
Embryo polarization is critical for mouse development; however, neither the regulatory clock nor the molecular trigger that it activates is known. Here, we show that the embryo polarization clock reflects the onset of zygotic genome activation, and we identify three factors required to trigger polarization. Advancing the timing of transcription factor AP-2 gamma (Tfap2c) and TEA domain transcription factor 4 (Tead4) expression in the presence of activated Ras homolog family member A (RhoA) induces precocious polarization as well as subsequent cell fate specification and morphogenesis. Tfap2c and Tead4 induce expression of actin regulators that control the recruitment of apical proteins on the membrane, whereas RhoA regulates their lateral mobility, allowing the emergence of the apical domain. Thus, Tfap2c, Tead4, and RhoA are regulators for the onset of polarization and cell fate segregation in the mouse
Impact of pension income on healthcare utilization of older adults in rural China.
ObjectiveIn China, rural residents experience poorer health conditions and a higher disease burden compared to urban residents but have lower healthcare services utilization. Rather than an insurance focus on enhanced healthcare services utilization, we aim to examine that whether an income shock, in the form of China's New Rural Pension Scheme (NRPS), will affect outpatient, inpatient and discretionary over-the-counter drug utilization by over 60-year-old rural NRPS residents.MethodsProviding a monthly pension of around RMB88 (USD12.97), NRPS covered all rural residents over 60 years old. Fuzzy regression discontinuity design (FRDD) was employed to explore the NRPS causal effect on healthcare services utilization, measured by outpatient and inpatient visits and discretionary over-the-counter drug purchases. The nationwide China Health and Retirement Longitudinal Study (CHARLS) 2018 provided the data.ResultsWithout significant changes in health status and medication needs, 60-plus-year-old NRPS recipients significantly increased the probability of discretionary OTC drug purchases by 33 percentage points. NRPS had no significant effect on the utilization of outpatient and inpatient utilization. The increase in the probability of discretionary OTC drug purchases from the NRPS income shock was concentrated in healthier and low-income rural residents. Robustness tests confirmed that FRDD was a robust estimation method and our results are robust.ConclusionNRPS was an exogenous income shock that significantly increased the probability of discretionary over-the-counter drug purchases among over 60-year-old rural residents, but not the utilization of inpatient or outpatient healthcare services. Income remains an important constraint for rural residents to improve their health. We recommend policymakers consider including commonly used over-the-counter drugs in basic health insurance reimbursements for rural residents; provide health advice for rural residents to make discretionary over-the-counter drug purchases; and to mount an information campaign on over-the-counter drug purchasing in order to increase the health awareness of rural residents
Symmetry and topology in antiferromagnetic spintronics
Antiferromagnetic spintronics focuses on investigating and using
antiferromagnets as active elements in spintronics structures. Last decade
advances in relativistic spintronics led to the discovery of the staggered,
current-induced field in antiferromagnets. The corresponding N\'{e}el
spin-orbit torque allowed for efficient electrical switching of
antiferromagnetic moments and, in combination with electrical readout, for the
demonstration of experimental antiferromagnetic memory devices. In parallel,
the anomalous Hall effect was predicted and subsequently observed in
antiferromagnets. A new field of spintronics based on antiferromagnets has
emerged. We will focus here on the introduction into the most significant
discoveries which shaped the field together with a more recent spin-off
focusing on combining antiferromagnetic spintronics with topological effects,
such as antiferromagnetic topological semimetals and insulators, and the
interplay of antiferromagnetism, topology, and superconductivity in
heterostructures.Comment: Book chapte