40 research outputs found
Time bound of atomic adiabatic evolution in the accelerated optical lattice
The accelerated optical lattice has emerged as a valuable technique for the
investigation of quantum transport physics and has found widespread application
in quantum sensing, including atomic gravimeters and atomic gyroscopes. In our
study, we focus on the adiabatic evolution of ultra-cold atoms within an
accelerated optical lattice. Specifically, we derive a time bound that delimits
the duration of atomic adiabatic evolution in the oscillating system under
consideration. To experimentally substantiate the theoretical predictions,
precise measurements to instantaneous band populations were conducted within a
one-dimensional accelerated optical lattice, encompassing systematic variations
in both lattice's depths and accelerations. The obtained experimental results
demonstrate a quantitatively consistent correspondence with the anticipated
theoretical expressions. Afterwards, the atomic velocity distributions are also
measured to compare with the time bound. This research offers a quantitative
framework for the selection of parameters that ensure atom trapped throughout
the acceleration process. Moreover, it contributes an experimental criterion by
which to assess the adequacy of adiabatic conditions in an oscillating system,
thereby augmenting the current understanding of these systems from a
theoretical perspective
Atomic Ramsey interferometry with S- and D-band in a triangular optical lattice
Ramsey interferometers have wide applications in science and engineering.
Compared with the traditional interferometer based on internal states, the
interferometer with external quantum states has advantages in some applications
for quantum simulation and precision measurement. Here, we develop a Ramsey
interferometry with Bloch states in S- and D-band of a triangular optical
lattice for the first time. The key to realizing this interferometer in
two-dimensionally coupled lattice is that we use the shortcut method to
construct pulse. We observe clear Ramsey fringes and analyze the
decoherence mechanism of fringes. Further, we design an echo pulse
between S- and D-band, which significantly improves the coherence time. This
Ramsey interferometer in the dimensionally coupled lattice has potential
applications in the quantum simulations of topological physics, frustrated
effects, and motional qubits manipulation
Biaxial strain modulated electronic structures of layered two-dimensional MoSiGeN4 Rashba systems
The two-dimensional (2D) MA2Z4 family has received extensive attention in
manipulating its electronic structure and achieving intriguing physical
properties. However, engineering the electronic properties remains a challenge.
Herein, based on first-principles calculations, we systematically investigate
the effect of biaxial strains on the electronic structures of 2D Rashba
MoSiGeN4 (MSGN), and further explore how the interlayer interactions affect the
Rashba spin splitting in such strained layered MSGNs. After applying biaxial
strains, the band gap decreases monotonically with increasing tensile strains
but increases when the compressive strains are applied. An
indirect-direct-indirect band gap transition is induced by applying a moderate
compressive strain (< 5%) in the MSGNs. Due to the symmetry breaking and
moderate spin-orbit coupling (SOC), the monolayer MSGN possess an isolated
Rashba spin splitting (R) near the Fermi level, which could be effectively
regulated to the Lifshitz transition (L) by biaxial strain. For instance, a
L-R-L transformation of Fermi surface is presented in monolayer and a more
complex and changeable L-R-L-R evolution is observed in bilayer and trilayer
MSGNs as the biaxial strain vary from -8% to 12%, which actually depend on the
appearance, variation, and vanish of the Mexican hat band in the absence of SOC
under different strains. The contribution of Mo-dz2 orbital hybridized with
N-pz orbital in the highest valence band plays a dominant role on the band
evolution under biaxial strains, where the R-L evolution corresponds to the
decreased Mo-dz2 orbital contribution. Our study highlights the biaxial strain
controllable Rashba spin splitting, in particular the introduction and even the
evolution of Lifshitz transition near Fermi surface, which makes the strained
MSGNs as promising candidates for future applications in spintronic devices.Comment: 21 pages, 7 figures, supplementary informatio
Clinical evaluation of premonitory urges in children and adolescents using the Chinese version of Individualized Premonitory Urge for Tics Scale
BackgroundPremonitory urges (PUs) have been the focus of recent efforts to assess the severity and develop interventions for tic disorders (TD). We aimed to investigate the PUs in TD and its comorbidities from multiple dimensions, using the Chinese version of the Premonitory Urge for Tics Scale (C-PUTS) and the Chinese version of the Individualized Premonitory Urge for Tics Scale (C-IPUTS), in order to provide perspectives for the diagnosis and management of TD in children and adolescents.MethodsA total of 123 cases were included in the study. The IPUTS was translated, back-translated, culturally adjusted, and pre-investigated to determine the items of the C-IPUTS. The reliability and validity of the C-IPUTS scale were evaluated by a questionnaire survey on children and adolescents with TD at the Developmental Pediatrics Department of the Second Hospital of Jilin University. Meanwhile, the C-PUTS, which had been evaluated and used in China, Yale Global Tic Severity Scale (YGTSS), Yale-Brown Obsessive-Compulsive Scale (Y-BOCS), Depression Self-Rating Scale (DSRS), Screen for Childhood Anxiety-Related Disorders (SCARED), Achenbach Child Behavior Checklist (CBCL), and Swanson, Nolan and Pelham, Version IV (SNAP-IV), were used to assess the association of PUs with tics and comorbidities of TD.ResultsAll dimensions of the C-IPUTS demonstrated good reliability and validity. Our findings suggested that PUs in children and adolescents in China occurred primarily at the head/face and neck/throat. The different dimensions of the C-IPUTS (number, frequency, and intensity) and C-PUTS were positively correlated with the YGTSS total score, while the C-PUTS was positively correlated with the Y-BOCS, SCARED, DSRS, and SNAP-IV scale total scores. The three dimensions of the C-IPUTS demonstrated correlations with anxiety severity and obsessive-compulsive symptoms.ConclusionThe C-IPUTS can be used to assess PUs reliably and effectively and provide further information for the C-PUTS from various dimensions in a Chinese setting. PUs relate to obsessive-compulsive symptoms, anxiety, attention deficit hyperactivity, and behavioral problems in children and adolescents with TDs. Accordingly, PUs evaluation using the C-IPUTS combined with the PUTS might provide useful information for future therapies for TDs to achieve greater tic reduction
Relationship between hydrogeochemical characteristics of hot springs and seismic activity in the Jinshajiang fault zone, Southeast Tibetan Plateau
Significant anomalous hydrogeochemical changes in hot spring water are detected during strong seismic cycles. It is now necessary to clarify the relationship between tectonic movements, earthquakes and the evolution of hot springs. In this paper, laboratory analyses of major, trace elements, δD, δ18O and 87Sr/86Sr values of 28 hot spring waters in the Jinshajiang fault zone (JSJFZ) in the northwestern boundary of the Sichuan-Yunnan block were conducted. The results showed that the primary source of water for JSJFZ hot springs was atmospheric precipitation. The geothermal reservoir temperature variation based on the silicon enthalpy mixing model ranged from 73 to 272°C. And the circulation depth range was 1.2–5.4 km. The segmentation characteristics of the 87Sr/86Sr values were related to the influence of source rocks on groundwater cycle processes. A conceptual model of the hydrologic cycle of hot springs explained the spatial distribution of earthquakes associated with tectonic movements. The Batang segment had the strongest water-rock reaction, the highest reservoir temperature and the deepest circulation depth; meanwhile, it was also an earthquake prone area. The fluid circulation of the JSJFZ corresponds well with the seismicity, which indicates that the hydrological characteristics of the hot spring water in a fracture zone play a crucial role in receiving information on seismic activity
Review of agricultural IoT technology
Agricultural Internet of Things (IoT) has brought new changes to agricultural production. It not only increases agricultural output but can also effectively improve the quality of agricultural products, reduce labor costs, increase farmers' income, and truly realize agricultural modernization and intelligence. This paper systematically summarizes the research status of agricultural IoT. Firstly, the current situation of agricultural IoT is illustrated and its system architecture is summarized. Then, the five key technologies of agricultural IoT are discussed in detail. Next, applications of agricultural IoT in five representative fields are introduced. Finally, the problems existing in agricultural IoT are analyzed and a forecast is given of the future development of agricultural IoT
Deformation and Cracking Resistance of MgO-Incorporated Cementitious Material: A Review
In China, MgO-based expansive agent (MEA) has been used for concrete shrinkage compensation and cracking control for over 40 years. The expansive behavior of MEA in cementitious materials could be manipulated to some extent by adjusting the calcination process of MEA and influenced by the restraint condition of the matrix. It is key to investigate the factors related to deformation and cracking resistance so that the desired performance of MEA in certain concrete structures could be achieved. This paper reviews the influence of key parameters such as hydration reactivity, dosage, and calcination conditions of MEA, the water-to-binder ratio, supplementary cementitious material, aggregates, and curing conditions on the deformation and cracking resistivity of cement paste, mortar, and concrete with an MEA addition. The numerical simulation methods and deformation prediction models are then summarized and analyzed for more reasonable estimations
Multimodal Identification Based on Fingerprint and Face Images via a Hetero-Associative Memory Method
Multimodal identification, which exploits biometric information from more than one biometric modality, is more secure and reliable than unimodal identification. Face recognition and fingerprint recognition have received a lot of attention in recent years for their unique advantages. However, how to integrate these two modalities and develop an effective multimodal identification system are still challenging problems. Hetero-associative memory (HAM) models store some patterns that can be reliably retrieved from other patterns in a robust way. Therefore, in this paper, face and fingerprint biometric features are integrated by the use of a hetero-associative memory method for multimodal identification. The proposed multimodal identification system can integrate face and fingerprint biometric features at feature level when the system converges to the state of asymptotic stability. In experiment 1, the predicted fingerprint by inputting an authorized user’s face is compared with the real fingerprint, and the matching rate of each group is higher than the given threshold. In experiment 2 and experiment 3, the predicted fingerprint by inputting the face of an unauthorized user and the stealing authorized user’s face is compared with its real fingerprint input, respectively, and the matching rate of each group is lower than the given threshold. The experimental results prove the feasibility of the proposed multimodal identification system