207 research outputs found
Stability of Multi-Dimensional Switched Systems with an Application to Open Multi-Agent Systems
Extended from the classic switched system, themulti-dimensional switched
system (MDSS) allows for subsystems(switching modes) with different state
dimensions. In this work,we study the stability problem of the MDSS, whose
state transi-tion at each switching instant is characterized by the
dimensionvariation and the state jump, without extra constraint imposed.Based
on the proposed transition-dependent average dwell time(TDADT) and the
piecewise TDADT methods, along with the pro-posed parametric multiple Lyapunov
functions (MLFs), sufficientconditions for the practical and the asymptotical
stabilities of theMDSS are respectively derived for the MDSS in the presenceof
unstable subsystems. The stability results for the MDSS areapplied to the
consensus problem of the open multi-agent system(MAS) which exhibits dynamic
circulation behaviors. It is shownthat the (practical) consensus of the open
MAS with disconnectedswitching topologies can be ensured by (practically)
stabilizingthe corresponding MDSS with unstable switching modes via theproposed
TDADT and parametric MLF methods.Comment: 12 pages, 9 figure
System optimization of an all-silicon IQ modulator : achieving 100 Gbaud dual polarization 32QAM
We experimentally demonstrate the highest, to the
best of our knowledge, reported net rate in a SiP IQ modulator.
At 100 Gbaud 32QAM (quadrature amplitude modulation), and
assuming 20% FEC (forward error correction) overhead, we
achieved a dual polarization net rate of 833 Gb/s. This record was
achieved by adapting digital signal processing to the challenging
pattern dependent distortion encountered in the nonlinear and
bandwidth limited regime. First the Mach Zehnder modulator
(MZM) operating point (trading off modulation efficiency and
3 dB bandwidth) and linear compensation (electrical and optical)
are jointly optimized. Next, the key application of nonlinear preand post-compensation are explored. We show that nonlinear
processing at the transmitter, in our case an iterative learning
control (ILC) method, is essential as post-processing alone could
not achieve reliable communications at 100 Gbaud. Nonlinear
post-compensation algorithms pushed the performance under the
FEC threshold with the introduction of structured intersymbol
interference in post processing and a simple one-step maximum
likelihood sequence detector. We provide detailed descriptions of
our methodology and results
Digital photoprogramming of liquid-crystal superstructures featuring intrinsic chiral photoswitches
Dynamic patterning of soft materials in a fully reversible and programmable manner with light enables applications in anti-counterfeiting, displays and labelling technology. However, this is a formidable challenge due to the lack of suitable chiral molecular photoswitches. Here, we report the development of a unique intrinsic chiral photoswitch with broad chirality modulation to achieve digitally controllable, selectable and extractable multiple stable reflection states. An anti-counterfeiting technique, embedded with diverse microstructures, featuring colour-tunability, erasability, reversibility, multi-stability and viewing-angle dependency of pre-recorded patterns, is established with these photoresponsive superstructures. This strategy allows dynamic helical transformation from the molecular and supramolecular to the macroscopic level using light-activated intrinsic chirality, demonstrating the practicality of photoprogramming photonics
Transient Receptor Potential V Channels Are Essential for Glucose Sensing by Aldolase and AMPK
Fructose-1,6-bisphosphate (FBP) aldolase links sensing of declining glucose availability to AMPK activation via the lysosomal pathway. However, how aldolase transmits lack of occupancy by FBP to AMPK activation remains unclear. Here, we show that FBP-unoccupied aldolase interacts with and inhibits endoplasmic reticulum (ER)-localized transient receptor potential channel subfamily V, inhibiting calcium release in low glucose. The decrease of calcium at contact sites between ER and lysosome renders the inhibited TRPV accessible to bind the lysosomal v-ATPase that then recruits AXIN:LKB1 to activate AMPK independently of AMP. Genetic depletion of TRPVs blocks glucose starvation-induced AMPK activation in cells and liver of mice, and in nematodes, indicative of physical requirement of TRPVs. Pharmacological inhibition of TRPVs activates AMPK and elevates NAD(+) levels in aged muscles, rejuvenating the animals' running capacity. Our study elucidates that TRPVs relay the FBP-free status of aldolase to the reconfiguration of v-ATPase, leading to AMPK activation in low glucose
Microbial Community Succession and Response to Environmental Variables During Cow Manure and Corn Straw Composting
In composting system, the composition of microbial communities is determined by the constant change in the physicochemical parameters. This study explored the dynamics of bacterial and fungal communities during cow manure and corn straw composting using high throughput sequencing technology. The relationships between physicochemical parameters and microbial community composition and abundance were also evaluated. The sequencing results revealed the major phyla included Proteobacteria, Bacteroidetes, Firmicutes, Chloroflexi and Actinobacteria, Ascomycota, and Basidiomycota. Linear discriminant analysis effect size (LEfSe) illustrated that Actinomycetales and Sordariomycetes were the indicators of bacteria and fungi in the maturation phase, respectively. Mantel test showed that NO3--N, NH4+-N, TN, C/N, temperature and moisture content significantly influenced bacterial community composition while only TN and moisture content had a significant effect on fungal community structure. Structural equation model (SEM) indicated that TN, NH4+-N, NO3--N and pH had a significant effect on fungal abundance while TN and temperature significantly affected bacterial abundance. Our finding increases the understanding of microbial community succession in cow manure and corn straw composting under natural conditions
Quantum metric nonlinear Hall effect in a topological antiferromagnetic heterostructure
Quantum geometry - the geometry of electron Bloch wavefunctions - is central
to modern condensed matter physics. Due to the quantum nature, quantum geometry
has two parts, the real part quantum metric and the imaginary part Berry
curvature. The studies of Berry curvature have led to countless breakthroughs,
ranging from the quantum Hall effect in 2DEGs to the anomalous Hall effect
(AHE) in ferromagnets. However, in contrast to Berry curvature, the quantum
metric has rarely been explored. Here, we report a new nonlinear Hall effect
induced by quantum metric by interfacing even-layered MnBi2Te4 (a PT-symmetric
antiferromagnet (AFM)) with black phosphorus. This novel nonlinear Hall effect
switches direction upon reversing the AFM spins and exhibits distinct scaling
that suggests a non-dissipative nature. Like the AHE brought Berry curvature
under the spotlight, our results open the door to discovering quantum metric
responses. Moreover, we demonstrate that the AFM can harvest wireless
electromagnetic energy via the new nonlinear Hall effect, therefore enabling
intriguing applications that bridges nonlinear electronics with AFM
spintronics.Comment: 19 pages, 4 figures and a Supplementary Materials with 66 pages, 4
figures and 3 tables. Originally submitted to Science on Oct. 5, 202
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