Algorithm Selection Method Based on Coupling Strength for Partitioned Analysis of Structure-Piezoelectric-Circuit Coupling

In this study, we propose an algorithm selection method based on coupling strength for the partitioned analysis ofstructure-piezoelectric-circuit coupling, which includes two types of coupling or inverse and direct piezoelectriccoupling and direct piezoelectric and circuit coupling. In the proposed method, implicit and explicit formulationsare used for strong and weak coupling, respectively. Three feasible partitioned algorithms are generated, namely(1) a strongly coupled algorithm that uses a fully implicit formulation for both types of coupling, (2) a weaklycoupled algorithm that uses a fully explicit formulation for both types of coupling, and (3) a partially stronglycoupled and partially weakly coupled algorithm that uses an implicit formulation and an explicit formulation forthe two types of coupling, respectively.Numerical examples using a piezoelectric energy harvester,which is a typicalstructure-piezoelectric-circuit coupling problem, demonstrate that the proposed method selects the most costeffectivealgorithm.

Magnetic-Field Dependence of Raman Coupling Strength in Ultracold ^(40)K Atomic Fermi Gas

We experimentally demonstrate the relation of Raman coupling strength with the external bias magnetic field in degenerate Fermi gas of 40K atoms. Two Raman lasers couple two Zeeman energy levels, whose energy splitting depends on the external bias magnetic field. The Raman coupling strength is determined by measuring the Rabi oscillation frequency. The characteristics of the Rabi oscillation is to be damped after several periods due to Fermi atoms in different momentum states oscillating with different Rabi frequencies. The experimental results show that the Raman coupling strength will decrease as the external bias magnetic field increases, which is in good agreement with the theoretical prediction.

Periodic synchronization of community networks with non-identical nodes uncertain parameters and adaptive coupling strength

In this paper, we propose a novel approach for simultaneously identifying unknown parameters and synchronizing time-delayed complex community networks with nonidentical nodes. Based on the LaSalle＇s invariance principle, a cri- teflon is established by constructing an effective control identification scheme and adjusting automatically the adaptive coupling strength. The proposed control law is applied to a complex community network which is periodically synchro- nized with different chaotic states. Numerical simulations are conducted to demonstrate the feasibility of the proposed method.

Coupling strength effect on shot noise in boron devices

The shot noise properties in boron devices are investigated with a tight-binding model and the non-equilibrium Green＇s function. It is found that the shot noise and Fano factors can be tuned by changing the structures, the size, and the coupling strength. The shot noise is suppressed momentarily as we switch on the bias voltage, and the electron correlation is significant. The Fano factors are more sensitive to the ribbon width than to the ribbon length in the full coupling context. In the weak-coupling context, the Fano factors are almost invariant with the increase of length and width over a wide bias range.

Temperature-dependent interlayer exchange coupling strength in synthetic antiferromagnetic [Pt/Co]_2/Ru/[Co/Pt]_4 multilayers

In this work, we experimentally investigated the thermal stability of the interlayer exchange coupling field(Hex) and strength(-Jiec) in synthetic antiferromagnetic(SAF) structure of [Pt(0.6)/Co(0.6)]2/Ru(tRu)/[Co(0.6)/Pt(0.6)]4multilayers with perpendicular anisotropy. Depending on the thickness of the spacing ruthenium(Ru) layer, the observed interlayer exchange coupling can be either ferromagnetic or antiferromagnetic. The Hexwere studied by measuring the magnetization hysteresis loops in the temperature range from 100 K to 700 K as well as the theoretical calculation of the-Jiec. It is found that the interlayer coupling in the multilayers is very sensitive to the thickness of Ru and temperature. The Hexexhibits either a linear or a non-linear dependence on the temperature for different thickness of Ru. Furthermore, our SAF multilayers show a high thermal stability even up to 600 K(Hex= 3.19 kOe,-Jiec= 1.97 erg/cm~2 for tRu=0.6 nm, the unit 1 Oe = 79.5775 A·m-1), which was higher than the previous studies.

Variable Coupling Strength of Silicene on Ag(lll)

We perform a scanning tunneling microscopy and spectroscopy study on the electronic structures of √3×√3- silicene on Ag（111）. It is found that the coupling strength of √3×√3-silicene with the Ag-（111） substrate is variable in different regions, giving rise to notable effects in experiments. This evidence of decoupling or variable interaction of silicene with the substrate is helpful to in-depth understanding of the structure and clectronic properties of silieene.

Collective behaviour of climate indices in the North Pacific air-sea system and its potential relationships with decadal climate changes

A climate network of six climate indices of the North Pacific air-sea system is constructed during the period of 1948-2009. In order to find out the inherent relationship between the intrinsic mechanism of climate index network and the important climate shift, the synchronization behaviour and the coupling behaviour of these indices are investigated. Results indicate that climate network synchronization happened around the beginning of the 1960s, in the middle of the 1970s and at the beginnings of the 1990s and the 2000s separately. These synchronization states were always followed by the decrease of the coupling coefficient. Each synchronization of the network was well associated with the abrupt phase or trend changes of annually accumulated abnormal values of North Pacific sea-surface temperature and 500-hPa height, among which the one that happened in the middle of the 1970s is the most noticeable climate shift. We can also obtain this mysterious shift from the first mode of the empirical orthogonal function of six indices. That is to say, abrupt climate shift in North Pacific air-sea system is not only shown by the phase or trend changes of climate indices, but also might be indicated by the synchronizing and the coupling of climate indices. Furthermore, at the turning point of 1975, there are also abrupt correlation changes in the yearly mode of spatial degree distribution of the sea surface temperature and 500-hPa height in the region of the North Pacific, which further proves the probability of climate index synchronization and coupling shift in air sea systems.

Stochastic synchronization for time-varying complex dynamical networks

This paper studies the stochastic synchronization problem for time-varying complex dynamical networks. This model is totally different from some existing network models. Based on the Lyapunov stability theory, inequality techniques, and the properties of the Weiner process, some controllers and adaptive laws are designed to ensure achieving stochastic synchronization of a complex dynamical network model. A sufficient synchronization condition is given to ensure that the proposed network model is mean-square stable. Theoretical analysis and numerical simulation fully verify the main results.

Generating mechanism of pathological beta oscillations in STN-GPe circuit model: A bifurcation study

Parkinson’s disease(PD)is characterized by pathological spontaneous beta oscillations(13 Hz-35 Hz)often observed in basal ganglia(BG)composed of subthalamic nucleus(STN)and globus pallidus(GPe)populations.From the viewpoint of dynamics,the spontaneous oscillations are related to limit cycle oscillations in a nonlinear system;here we employ the bifurcation analysis method to elucidate the generating mechanism of the pathological spontaneous beta oscillations underlined by coupling strengths and intrinsic properties of the STN-GPe circuit model.The results reveal that the increase of inter-coupling strength between STN and GPe populations induces the beta oscillations to be generated spontaneously,and causes the oscillation frequency to decrease.However,the increase of intra-coupling(self-feedback)strength of GPe can prevent the model from generating the oscillations,and dramatically increase the oscillation frequency.We further provide a theoretical explanation for the role played by the inter-coupling strength of GPe population in the generation and regulation of the oscillations.Furthermore,our study reveals that the intra-coupling strength of the GPe population provides a switching mechanism on the generation of the abnormal beta oscillations:for small value of the intra-coupling strength,STN population plays a dominant role in inducing the beta oscillations;while for its large value,the GPe population mainly determines the generation of this oscillation.

Entrainment range affected by the difference in sensitivity to light-information between two groups of SCN neurons

The mammals can not only entrain to the natural 24-h light–dark cycle, but also to the artificial cycle with non 24-h period through the main clock named suprachiasmatic nucleus in the brain. The range of the periods of the artificial cycles which the suprachiasmatic nucleus(SCN) can entrain, is called entrainment range reflecting the flexibility of the SCN. The SCN can be divided into two groups of neurons functionally, based on the different sensitivities to the light information. In the present study, we examined whether the entrainment range is affected by this difference in the sensitivity by a Poincaré model. We found that the relationship of the entrainment range to the difference depends on the coupling between two groups. When the coupling strength is much smaller than the light intensity, the relationship is parabolic-like, and the maximum of the entrainment range is obtained with no difference of the sensitivity. When the coupling strength is much larger than the light intensity, the relationship is monotonically changed, and the maximum of the entrainment range is obtained when the difference is the largest. Our finding may provide an explanation for the exitance of the difference in the sensitivity to light-information as well as shed light on how to increase the flexibility of the SCN represented by widening the entrainment range.

Investigation on the dynamic behaviors of the coupled memcapacitor-based circuits

In this paper, by referring to the concept of coupled memristors （MRs） and considering the flux coupling connection, the constitutive relations for describing the coupled memcapacitors （MCs） are theoretically deduced. The dynamic behaviors of dual coupled MCs in serial and parallel connections are analyzed in terms of identical or opposite polarities for the first time. Based on the derived constitutive relations of the two coupled MCs, the modified relaxation oscillators （ROs） are obtained with the purpose of achieving controllable oscillation frequency and duty cycle. In consideration of different parameter configurations, the experimental investigation is carried out by using practical off-the-shelf circuit components to verify the correction of the theoretical calculation with numerical simulation of the coupled MCs and its application in ROs.

Entanglement in a generalized Jaynes-Cummings model

We investigate the pairwise entanglement and global entanglement in a generalized Jaynes-Cummings model, which can be used to realize Greenberger-Horne-Zeilinger （GHZ） entangled state （Zheng S B 2001 Phys. Rev. Lett. 87 230404）. Our results show that the W-type entangled states cannot be generated based on the model. The dependences of entanglement on Rabi frequency λ and dipole-dipole coupling strength Ω are given. It is found that there exists the quantum phase transition when λ= Ω. For typical experimental data, the critical temperature for pairwise entanglement is on the order of 10^-6 K. Based on these results, two strategies that overcome decoherence are proposed.

Performance Degradation of the Repeated Recycled Aggregate Concrete with 70% Replacement of Three-generation Recycled Coarse Aggregate

The feasibility of using different generations recycled coarse aggregate（RCA） on structural concrete was fully evaluated by studying the performance of the recycled coarse aggregates and their corresponding concretes, the different generations of RCA were recycled by following the repeated mode of ‘concrete-waste concrete-coarse aggregate-concrete＇. Moreover, the focus was on ‘three generations＇ of repeated RCAs, the RCA was produced by crushing and regenerating the artificial accelerated degraded concrete, the process was designed to follow the nature degradation of the concrete with a coupling action of accelerated carbonation and bending load. The properties of x-generation（x=1, 2 or 3） of repeated RCA were systematically investigated and the compressive and splitting tensile strengths of relating structural concretes（with 70% replacement of x-generation of RCA） were studied accordingly. The results show a competent compressive and splitting tensile strength of 30 MPa at 28 th day of structural concretes with all generations of repeated RAC. And the gradual degraded performance of the repeated RCAs was observed with an increased numbers of repetition（1〉2〉3 generations）, the overall performances of all repeated RCAs fulfill the Class Ⅲ according to Chinese Standards GB25177-2010. Our gained insight demonstrates a feasibility of using at least 3 generations of repeated RCA for the production of normal structural concrete.

Halide Anchors for Single-Cluster Electronics

Due to their unique electronic structure,well-defined metal clusters at the atomic level are promising materials for single-cluster electronics.However,coupling between the electrode and the cluster remains challenging mainly due to the coverage of bulky ligands on the noble clusters.Using the scanning tunneling microscopy break junction(STM-BJ)technique,we have developed a“direct contact”approach to fabrication and investigation of the charge transport through single-cluster junctions of AgCu bimetallic metal clusterswith different halide anchors.Wefound that the electrodes could make contact directly with the surface halides of the single-cluster junctions and experience different contact resistance from different halogen atoms.Experiments and calculations reveal that the halide anchors provided efficient coupling between the cluster and the electrode,and the enhanced coupling with various halide anchors promoted electron transport and improved transmission probability.Our work offers a“direct contact”strategy for interface design between clusters of noble metals and electrodes,an essential step in progress toward single-cluster electronics.

Capacitive beam position monitors for the low-β beam of the Chinese ADS proton linac

Beam Position Monitors（BPMs） for the low-β beam of the Chinese Accelerator Driven Subcritical system（CADS） Proton linac are of the capacitive pick-up type.They provide higher output signals than that of the inductive type.This paper will describe the design and tests of the capacitive BPM system for the low-β proton linac,including the pick-ups,the test bench and the read-out electronics.The tests done with an actual proton beam show a good agreement between the measurements and the simulations in the time domain.

单层硒化钨/二维钙钛矿异质结层间耦合强度的定点调控

与过渡金属硫化物中的层间激子相比,过渡金属硫化物与二维钙钛矿间的层间激子有更高的鲁棒性,且其光学性质与层间旋转角和是否退火无关.因此,过渡金属硫化物与二维钙钛矿间的层间激子正成为一个新的研究激子的体系.层间激子的有效控制是实现其功能和提高其性能的关键,然而,目前缺少对过渡金属硫化物与二位钙钛矿间层间激子有效控制的研究.本文利用二氧化硅纳米柱实现了单层WSe_(2)和(iso-BA)_(2)PbI_(4)二维钙钛矿间层间激子的定点调控.与过渡金属硫化物层间激子在应力作用下红移的现象相反,我们在过渡金属硫化物和二维钙钛矿间的层间激子中观测到10 nm的蓝移以及2.5倍的信号增强.我们推断该蓝移是由层间间距减小导致的层间耦合强度增大引起的.该推断也由观测到的层间激子相对自由激子的比例随着耦合强度的增大而增大的现象验证.同时,层间耦合还可以通过改变纳米柱的直径和高度进行调控.特别地,由于对称性被破坏,我们在直径/高度比为0.6的纳米柱上观测到三线态层间激子,且层间激子的各项异性证明其对称性确实已被破坏.总之,本研究对调控基于层间激子的光电器件、激子局域态和量子光源具有一定促进作用.

Multi-scale simulation of three-dimensional thin-film lubrication

For three-dimensional(3D)mono-layer molecular thin-film lubrication,the elasticity of the substrate affects the tribological behaviors of a thin fluid film confined by two solid substrates.To account for the elastic effects,this study establishes a multi-scale method that combines an atomistic description of the near region with a coarse-grained description of the far region of the solid substrate to simulate the thin-film lubrication.It is demonstrated that for a given temperature range and film-substrate coupling strength,the multi-scale method is in excellent agreement with the fully atomistic simulation.This study reveals that the elastic response of the substrate can be effectively rendered in the hybrid scheme.In the application of the multi-scale method to investigate the tribological properties of the multi-layer molecular thin-film lubrication,it is determined that the systematic static friction coefficient monotonously decreases as the molecular layer thickness in the fluid film increases.In comparison to the mono-layer molecular thin-film lubrication,the multi-layer molecular thin-film lubrication plays a role in reducing the friction and wear of the system.

Modifying glass fiber surface with grafting acrylamide by UV-grafting copolymerization for preparation of glass fiber reinforced PVDF composite membrane

Experimental design and response surface methodology（RSM） were used to optimize the modification of conditions for glass surface grafting with acrylamide（AM） monomer for preparation of a glass fiber reinforced poly（vinylidene fluoride）（PVDF） composite membrane（GFRP-CM）. The factors considered for experimental design were the UV（ultraviolet）-irradiation time, the concentrations of the initiator and solvent, and the kinds and concentrations of the silane coupling agent. The optimum operating conditions determined were UV-irradiation time of 25 min, an initiator concentration of 0–0.25 wt.%,solvent of N-Dimethylacetamide（DMAC）, and silane coupling agent KH570 with a concentration of 7 wt.%. The obtained optimal parameters were located in the valid region and the experimental confirmation tests conducted showed good accordance between predicted and experimental values. Under these optimal conditions, the water absorption of the grafted modified glass fiber was improved from 13.6% to 23%; the tensile strength was enhanced and the peeling strength of the glass fiber reinforced PVDF composite membrane was improved by 23.7% and 32.6% with an AM concentration at 1 wt.% and 2 wt.%. The surface composition and microstructure of AM grafted glass fiber were studied via several techniques including Field Emission Scanning Electron Microscopy（FESEM）, Fourier transform infrared spectroscopy-attenuated total reflectance（FTIR-ATR） and energy dispersive X-ray spectroscopy（EDX）. The analysis of the EDX and FTIR-ATR results confirmed that the AM was grafted to the glass fiber successfully by detecting and proving the existence of nitrogen atoms in the GFRP-CM.