Non-Hermitian skin effect in a single trapped ion

Non-Hermitian skin effect (NHSE) describes the exponential localization of all eigenstates toward boundaries in non-Hermitian systems, and has attracted intense research interest of late. Here we theoretically propose a scheme in which the NHSE significantly impacts the external motion of a single trapped ion through complex spin-motion dynamics. On the one hand, we show the competition between the NHSE and the coherent Bloch dynamics. On the other hand, since the NHSE manifests as a non-reciprocal flow in occupied phonon modes, we demonstrate that such dynamics can have potential applications in cooling and sensing. Our proposal can be readily implemented using existing experimental techniques, and offers a scalable (in terms of the available ions and phonon modes) simulation platform for relevant non-Hermitian physics.Comment: 9 pages, 8 figure

Analysis of a discrete-layout bimorph disk elements piezoelectric deformable mirror

We introduce a discrete-layout bimorph disk elements piezoelectric deformable mirror (DBDEPDM), driven by the circular flexural-mode piezoelectric actuators. We formulated an electromechanical model for analyzing the performance of the new deformable mirror. As a numerical example, a 21-actuators DBDEPDM with an aperture of 165 mm was modeled. The presented results demonstrate that the DBDEPDM has a stroke larger than 10  μm and the resonance frequency is 4.456 kHz. Compared with the conventional piezoelectric deformable mirrors, the DBDEPDM has a larger stroke, higher resonance frequency, and provides higher spatial resolution due to the circular shape of its actuators. Moreover, numerical simulations of influence functions on the model are provided

Interfollicular Epidermal Differentiation is Gradualistic Rather than Stepwis with GRHL3 Controlling Progression from Stem to Transition Cell States

Although interfollicular epidermal (IFE) differentiation is thought to bestepwise as reflected in sharp boundaries between the basal, spinous, granularand cornified layers, this prediction has not been studied at a single cellresolution. We used single cell RNA-seq to show that IFE differentiation is bestdescribed as a single step gradualistic process with a large number of transitioncells between the basal and spinous layer. RNA-velocity analysis identifies acommitment point that separates the plastic basal and transition cell state fromthe unidirectionally differentiating cells. We also show that GRHL3, best knownfor promoting IFE terminal differentiation, has a major function in suppressingepidermal stem cell expansion and the emergence of an abnormal stem cell stateby suppressing Wnt signaling in stem cells

Interfollicular Epidermal Differentiation is Gradualistic Rather than Stepwis with GRHL3 Controlling Progression from Stem to Transition Cell States

Although interfollicular epidermal (IFE) differentiation is thought to bestepwise as reflected in sharp boundaries between the basal, spinous, granularand cornified layers, this prediction has not been studied at a single cellresolution. We used single cell RNA-seq to show that IFE differentiation is bestdescribed as a single step gradualistic process with a large number of transitioncells between the basal and spinous layer. RNA-velocity analysis identifies acommitment point that separates the plastic basal and transition cell state fromthe unidirectionally differentiating cells. We also show that GRHL3, best knownfor promoting IFE terminal differentiation, has a major function in suppressingepidermal stem cell expansion and the emergence of an abnormal stem cell stateby suppressing Wnt signaling in stem cells

Three Vectors Model Predictive Torque Control Without Weighting Factor Based on Electromagnetic Torque Feedback Compensation

Finite control set-model predictive torque control (FCS-MPTC) depends on the system parameters and the weight coefficients setting. At the same time, since the actual load disturbance is unavoidable, the model parameters are not matched, and there is a torque tracking error. In traditional FCS-MPTC, the outer loop—that is, the speed loop—adopts a classic Proportional Integral (PI) controller, abbreviated as PI-MPTC. The pole placement of the PI controller is usually designed by a plunge-and-test, and it is difficult to achieve optimal dynamic performance and optimal suppression of concentrated disturbances at the same time. Aiming at squirrel cage induction motors, this paper first proposes an outer-loop F-ETFC-MPTC control strategy based on a feed-forward factor for electromagnetic torque feedback compensation (F-ETFC). The electromagnetic torque was imported to the input of the current regulator, which is used as the control input signal of feedback compensation of the speed loop; therefore, the capacity of an anti-load-torque-disturbance of the speed loop was improved. The given speed is quantified by a feed-forward factor into the input of the current regulator, which is used as the feed-forward adjustment control input of the speed controller to improve the dynamic response of the speed loop. The range of the feed-forward factor and feed-back compensation coefficient can be obtained according to the structural analysis of the system, which simplifies the process of parameter design adjustment. At the same time, the multi-objective optimization based on the sorting method replaces the single cost function in traditional control, so that the selection of the voltage vector works without the weight coefficient and can solve complicated calculation problems in traditional control. Finally, according to the relationship between the voltage vector and the switch state, the virtual six groups of three vector voltages can be adjusted in both the direction and amplitude, thereby effectively improving the control performance and reducing the flow rate and torque ripple. The experiment is based on the dSPACE platform, and experimental results verify the feasibility of the proposed F-ETFC-MPTC. Compared with traditional PI-MPTC, the feed-forward factor can effectively improve the stability time of the system by more than 10 percent, electromagnetic torque feedback compensation can improve the anti-load torque disturbance ability of the system by more than 60 percent, and the three-vector voltage method can effectively reduce the disturbance

Nonlinear El Niño impacts on the global economy under climate change

Abstract The El Niño-Southern Oscillation (ENSO) is a consequential climate phenomenon affecting global extreme weather events often with largescale socioeconomic impacts. To what extent the impact affects the macroeconomy, how long the impact lasts, and how the impact may change in a warming climate are important questions for the field. Using a smooth nonlinear climate-economy model fitted with historical data, here we find a damaging impact from an El Niño which increases for a further three years after initial shock, amounting to multi-trillion US dollars in economic loss; we attribute a loss of US$2.1 T and US$3.9 T globally to the 1997-98 and 2015-16 extreme El Niño events, far greater than that based on tangible losses. We find impacts from La Niña are asymmetric and weaker, and estimate a gain of only US$0.06 T from the 1998-99 extreme La Niña event. Under climate change, economic loss grows exponentially with increased ENSO variability. Under a high-emission scenario, increased ENSO variability causes an additional median loss of US$33 T to the global economy at a 3% discount rate aggregated over the remainder of the 21st century. Thus, exacerbated economic damage from changing ENSO in a warming climate should be considered in assessments of mitigation strategies

Near-term projection of Amazon rainfall dominated by phase transition of the Interdecadal Pacific Oscillation

Abstract The Amazon basin experienced a prolonged drought condition during the 2010s, leading to a large-scale forest degradation destructive to ecosystems and human society. Elusive are issues as to whether the decadal drought is driven by external forcing or internal variability, and whether the drought will continue or recover soon. Using large ensemble simulations from a state-of-the-art climate model, here we find a negative-to-positive phase transition of the Interdecadal Pacific Oscillation (IPO) explains ~45% (~40–49%) of the observed decadal drought of Amazon rainfall since 2010, much greater than the role of external forcing (~12%). Constraining future IPO phase transition reduces the uncertainty by ~38% from a range of −0.73 to + 0.31 mm day−1 decade−1 to a range of −0.42 to + 0.23 mm day−1 decade−1, of the near-term Amazon rainfall projection before 2040 under a mid-intensity emission scenario. Thus, the IPO plays a crucial role in the post-2010 drying and the near-term rainfall projection

Murine interfollicular epidermal differentiation is gradualistic with GRHL3 controlling progression from stem to transition cell states.

The interfollicular epidermis (IFE) forms a water-tight barrier that is often disrupted in inflammatory skin diseases. During homeostasis, the IFE is replenished by stem cells in the basal layer that differentiate as they migrate toward the skin surface. Conventionally, IFE differentiation is thought to be stepwise as reflected in sharp boundaries between its basal, spinous, granular and cornified layers. The transcription factor GRHL3 regulates IFE differentiation by transcriptionally activating terminal differentiation genes. Here we use single cell RNA-seq to show that murine IFE differentiation is best described as a single step gradualistic process with a large number of transition cells between the basal and spinous layer. RNA-velocity analysis identifies a commitment point that separates the plastic basal and transition cell state from unidirectionally differentiating cells. We also show that in addition to promoting IFE terminal differentiation, GRHL3 is essential for suppressing epidermal stem cell expansion and the emergence of an abnormal stem cell state by suppressing Wnt signaling in stem cells