DYNAMIC FOR A STOCHASTIC MULTI-GROUP AIDS MODEL WITH SATURATED INCIDENCE RATE

In this paper,a stochastic multi-group AIDS model with saturated incidence rate is studied.We prove that the system is persistent in the mean under some parametric restrictions.We also obtain the sufficient condition for the existence of the ergodic stationary distribution of the system by constructing a suitable Lyapunov function.Our results indicate that the existence of ergodic stationary distribution does not rely on the interior equilibrium of the corresponding deterministic system,which greatly improves upon previous results.

不同pH条件下硫化钼纳米片吸附Cd(Ⅱ)的微观机制研究

本研究结合静态实验和X射线吸收精细结构谱学(EXAFS)评估了硫化钼纳米片对重金属Cd(Ⅱ)的吸附行为和微观机制。结果表明:Cd(Ⅱ)在硫化钼纳米片上的吸附受溶液pH、反应时间和温度的显著影响,但不受离子强度的影响。在pH 3.3~9.6范围内, pH升高显著促进了硫化钼对Cd(Ⅱ)的吸附量,但不改变吸收速率、吸附等温线和热力学。二级动力学模型能更好地拟合该吸附平衡,且内表面颗粒扩散模型显示了吸附过程中的三个典型阶段。等温线和热力学分析说明Cd(Ⅱ)在硫化钼上的吸附是异质性的、自发的、吸热的和不可逆的过程。EXAFS光谱学分析揭示了该吸附存在两种类型:在较低的pH(3.56,6.48)条件下,内表面络合以Cd–S配位键为主;在较高的pH(9.57)条件下,出现Cd(OH)2沉淀,且配位键以Cd–O和Cd–Cd的形式存在。这些研究结果对于评估重金属离子和硫化钼纳米片在分子水平上的作用机理提供了新的视野。

Plasma-induced grafting of acrylic acid on bentonite for the removal of U(VI) from aqueous solution

Fabrication of reusable adsorbents with satisfactory adsorption capacity and using environmentfriendly preparation processes is required for the environment-related applications. In this study,acrylic acid（AA） was grafted onto bentonite（BT） to generate an AA-graft-BT（AA-g-BT）composite using a plasma-induced grafting technique considered to be an environment-friendly method. The as-prepared composite was characterized by scanning electron microscopy, x-ray powder diffraction, thermal gravity analysis, Fourier transform infrared spectroscopy and Barrett–Emmett–Teller analysis, demonstrating the successful grafting of AA onto BT. In addition, the removal of uranium（VI）（U（VI）） from contaminated aqueous solutions was examined using the as-prepared composite. The influencing factors, including contact time,p H value, ionic strength, temperature, and initial concentration, for the removal of U（VI） were investigated by batch experiments. The experimental process fitted best with the pseudo-secondorder kinetic and the Langmuir models. Moreover, thermodynamic investigation revealed a spontaneous and endothermic process. Compared with previous adsorbents, AA-g-BT has potential practical applications in treating U（VI）-contaminated solutions.

Heralded entanglement purification protocol using high-fidelity parity-check gate based on nitrogen-vacancy center in optical cavity

The decoherence of entangled states caused by the noisy channel is a salient problem for reducing the fidelity of quantum communication.Here we present a heralded two-photon entanglement purification protocol(EPP)using heralded high-fidelity parity-check gate(HH-PCG),which can increase the entanglement of nonlocal two-photon polarization mixed state.The HH-PCG is constructed by the input-output process of nitrogen-vacancy(NV)center in diamond embedded in a single-sided optical cavity,where the errors caused by the imperfect interaction between the NV center-cavity system and the photon can be heralded by the photon detector.As the unwanted components can be filtrated due to the heralded function,the fidelity of the EPP scheme can be enhanced considerably,which will increase the fidelity of quantum communication processing.

Stratified magnetohydrodynamic flow of tangent hyperbolic nanofluid induced by inclined sheet

This paper studies stratified magnetohydrodynamic （MHD） flow of tan- gent hyperbolic nanofluid past an inclined exponentially stretching surface. The flow is subjected to velocity, thermal, and solutal boundary conditions. The partial differential systems are reduced to ordinary differential systems using appropriate transformations. The reduced systems are solved for convergent series solutions. The velocity, temperature, and concentration fields are discussed for different physical parameters. The results indi- cate that the temperature and the thermal boundary layer thickness increase noticeably for large values of Brownian motion and thermophoresis effects. It is also observed that the buoyancy parameter strengthens the velocity field, showing a decreasing behavior of temperature and nanoparticle volume fraction profiles.

一类k-Hessian方程解的存在性和渐近稳定性

该文考虑了边界爆破k-Hessian问题Sk(λ(D^(2)z))=b(x)f(z),x∈Ω,z|■Ω=+∞,其中,Ω■R^(N)是一个严格凸的光滑有界区域.文章通过单调迭代方法、上下解方法和Karamata正则变化理论得到了k-Hessian方程径向对称正解的存在性和严格凸的爆破正解的边界渐近行为.

Synchronization performance in time-delayed random networks induced by diversity in system parameter

Synchronization rhythm and oscillating in biological systems can give clues to understanding the cooperation and competition between cells under appropriate biological and physical conditions. As a result, the network setting is appreciated to detect the stability and transition of collective behaviors in a network with different connection types. In this paper, the synchronization performance in time-delayed excitable homogeneous random networks（EHRNs） induced by diversity in system parameters is investigated by calculating the synchronization parameter and plotting the spatiotemporal evolution pattern, and distinct impacts induced by parameter-diversity are detected by setting different time delays. It is found that diversity has no distinct effect on the synchronization performance in EHRNs with small time delay being considered. When time delay is increased greatly, the synchronization performance of EHRN degenerates remarkably as diversity is increased. Surprisingly, by setting a moderate time delay, appropriate parameter-diversity can promote the synchronization performance in EHRNs, and can induce the synchronization transition from the asynchronous state to the weak synchronization. Moreover, the bistability phenomenon, which contains the states of asynchronous state and weak synchronization,is observed. Particularly, it is confirmed that the parameter-diversity promoted synchronization performance in time-delayed EHRN is manifested in the enhancement of the synchronization performance of individual oscillation and the increase of the number of synchronization transitions from the asynchronous state to the weak synchronization. Finally, we have revealed that this kind of parameter-diversity promoted synchronization performance is a robust phenomenon.

带有对数非线性项的回火分数p-Laplace系统的驻波解

本文引入回火分数p-Laplace(-△-λ)_(p)^(s),讨论了含有对数非线性项的回火分数p-Laplace系统的驻波解.通过极值原理和直接移动平面法,分别研究在全空间和上半空间上驻波解的径向对称性和非存在性.

Synchronization and wave propagation in neuronal network under field coupling

Electric and chemical synapse play important role in connecting neurons and thus signal propagation can be realized between neurons. External electric stimulus can change the excitability of neuron and then the electrical activities can be modulated completely. Continuous fluctuation of ion concentration in cell can induce complex time-varying electromagnetic field during the exchange of charged ions across the membrane of neuron. Polarization and magnetization in the media(and neuron), which exposed to electromagnetic radiation, can modulate the dynamical response and mode transition in electrical activities of neurons. In this paper, magnetic flux is used to describe the effect of electromagnetic field, and the three-variable HindmarshRose neuron model is updated to propose a four-variable neuron model that the effect of electromagnetic induction and radiation can be explained. Based on the physical law of electromagnetic induction, exchange of charged ions and flow of ion currents will change the distribution of electromagnetic filed in cell, and each neuron will be exposed to the superimposed field triggered by other neurons. Therefore, signal exchange could occur even synapse coupling between neurons is removed in the case of field coupling. A chain network is proposed to investigate the signal exchange between neurons under field coupling when synapse coupling is not available. It is found that field coupling between neurons can change the collective behaviors in electrical activities. A statistical factor of synchronization and spatial patterns are calculated, these results confirmed that field coupling is effective for signal communication between neurons. In the end, open problems are suggested for readers' extensive guidance in this field.

Differential coupling contributes to synchronization via a capacitor connection between chaotic circuits

Nonlinear oscillators and circuits can be coupled to reach synchronization and consensus. The occurrence of complete synchronization means that all oscillators can maintain the same amplitude and phase, and it is often detected between identical oscillators. However, phase synchronization means that the coupled oscillators just keep pace in oscillation even though the amplitude of each node could be different. For dimensionless dynamical systems and oscillators, the synchronization approach depends a great deal on the selection of coupling variable and type. For nonlinear circuits, a resistor is often used to bridge the connection between two or more circuits, so voltage coupling can be activated to generate feedback on the coupled circuits. In this paper, capacitor coupling is applied between two Pikovsk-Rabinovich(PR) circuits, and electric field coupling explains the potential mechanism for differential coupling. Then symmetric coupling and cross coupling are activated to detect synchronization stability, separately. It is found that resistor-based voltage coupling via a single variable can stabilize the synchronization, and the energy flow of the controller is decreased when synchronization is realized. Furthermore, by applying appropriate intensity for the coupling capacitor, synchronization is also reached and the energy flow across the coupling capacitor is helpful in regulating the dynamical behaviors of coupled circuits, which are supported by a continuous energy exchange between capacitors and the inductor. It is also confirmed that the realization of synchronization is dependent on the selection of a coupling channel. The approach and stability of complete synchronization depend on symmetric coupling, which is activated between the same variables. Cross coupling between different variables just triggers phase synchronization. The capacitor coupling can avoid energy consumption for the case with resistor coupling, and it can also enhance the energy exchange between two coupled circuits.

Astrocyte calcium wave induces seizure-like behavior in neuron network

It has been revealed experimentally that astrocytes can participate in synaptic transmission by modulating and responding to the release of neurotransmitters with calcium elevations. Researches suggest that seizure-like discharges(SDs) or seizure-like firings(SFs) in neurons, characterizing neurological disorder, may arise locally in restricted areas(focal area) and then propagate throughout the brain. But the underlying mechanism remains unclear. To study the possible role astrocytes playing in the SDs propagation, we construct a minimal neuron-astrocyte network model by connecting a neurons chain and an astrocytes chain.The focal area is modelled by an IP3 reservoir which provides persistent IP3 out-flux. The study suggests that calcium wave propagation in astrocytes determines the propagation of SDs in the connected neurons. On the other hand, SDs in neurons allows the calcium wave propagates longer distance in the astrocytes, which suggests the mutually cooperating of astrocytes and neurons in accomplishing SD propagation. Furthermore, once SDs propagate and occupy the neuron network, it could not be terminated by recovery of the focal area. The results may imply that treatment of brain disorders should not only focus on local area but the whole neuron network.

二维有机-无机杂化钙钛矿:从材料性能到器件应用（英文）

二维(2D)钙钛矿材料(包括纯2D和准2D)是在传统意义上的三维钙钛矿晶格中插入大基团卤化铵形成的.在过去的20年里,二维钙钛矿材料种类不断丰富,相关理论研究不断深入,在光电器件领域的应用不断拓展.本综述介绍了2D钙钛矿材料的基本形成机制和性能,汇总和比较了2D钙钛矿薄膜的制备方法,并给出了其在太阳电池以及发光二极管领域的应用实例.最后,提出了该领域亟待解决的问题,以及未来的研究趋势.

A new photosensitive neuron model and its dynamics

Biological neurons can receive inputs and capture a variety of external stimuli,which can be encoded and transmitted as different electric signals.Thus,the membrane potential is adjusted to activate the appropriate firing modes.Indeed,reliable neuron models should take intrinsic biophysical effects and functional encoding into consideration.One fascinating and important question is the physical mechanism for the transcription of external signals.External signals can be transmitted as a transmembrane current or a signal voltage for generating action potentials.We present a photosensitive neuron model to estimate the nonlinear encoding and responses of neurons driven by external optical signals.In the model,a photocell(phototube)is used to activate a simple FitzHugh-Nagumo(FHN)neuron,and then external optical signals(illumination)are imposed to excite the photocell for generating a time-varying current/voltage source.The photocell-coupled FHN neuron can therefore capture and encode external optical signals,similar to artificial eyes.We also present detailed bifurcation analysis for estimating the mode transition and firing pattern selection of neuronal electrical activities.The sampled time series can reproduce the main characteristics of biological neurons(quiescent,spiking,bursting,and even chaotic behaviors)by activating the photocell in the neural circuit.These results could be helpful in giving possible guidance for studying neurodynamics and applying neural circuits to detect optical signals.

General hyperentanglement concentration for polarization- spatial-time-bin multi-photon systems with linear optics

Hyperentanglement has attracted considerable attention recently because of its high-capacity for long- distance quantum communication. In this study, we present a hyperentanglement concentration pro- tocol （hyper-ECP） for nonlocal three-photon systems in the polarization, spatial-mode, and time- bin partially hyperentangled Greenberger-Horne-Zeilinger （GHZ） states using the Schmidt projection method. In our hyper-ECP, the three distant parties must perform the parity-check measurements on the polarization, spatial-mode, and time-bin degrees of freedom, respectively, using linear optical ele- ments and Pockels cells, and only two identical nonlocal photon systems are required. This hyper-ECP can be directly extended to the N-photon hyperentangled GHZ states, and the success probability of this general hyper-ECP for a nonlocal N-photon system is the optimal one, regardless of the photon number N.

Coherent and incoherent theories for photosynthetic energy transfer

自然界的光合作用有一个显著的特点,即能量传递效率近乎100%.近年来,由于光合作用实验技术的飞速发展,譬如二维光谱实验和单分子泵浦探测实验,其能量传输过程中的量子相干效应已经在实验上得到了证实.传统的非相干理论能够有效计算能量转移效率,如广义的F?rster理论和修正的Redfield理论.然而,为了描述光合作用中的量子相干效应,人们必须利用量子相干理论.例如,除了传统的Redfield理论之外,还有级联运动方程、量子路径积分、相干修正的Redfield理论、小极化子量子主方程、广义Bloch-Redfield理论等.本文综述了上述方法的主要内容,不仅有助于对自然界光合作用中激子能量转移的量子动力学进行有效的量子模拟,并对人工太阳能收集装置的设计提供了一定的指导作用.

初始值敏感的周期和混沌振荡模态系统同步稳定性（英文）

目的:具有记忆特性的振子系统的模态选择对初始值具有敏感性。本文旨在探讨初始值控制的振子的耦合同步稳定一致性问题。创新点:1.两个周期振子耦合后达到混沌同步;2.周期振子和混沌振子耦合后达到周期性振荡同步。方法:1.通过分岔分析,研究振荡模态和初始值选择之间的关系(图2、6和8);2.通过数值计算,研究两个周期振子在耦合下的混沌同步关系(图7);3.通过计算同步因子和斑图,分析同步一致性对耦合强度与记忆函数增益的依赖程度(图9和10);4.通过现场可编程门阵列验证动力系统模态对初始值的依赖程度(图11和12)。结论:1.具有记忆函数的非线性振子的动力学行为(如吸引子)在参数固定的情况下与初始值选取有关。2.不同类型振子的耦合可以达到多样同步行为;周期振子耦合达到混沌同步;周期振子耦合混沌振子可以抑制混沌。3.包含记忆函数的振子网络耦合同步非常困难。

Quantum error rejection for faithful quantum communication over noise channels

Quantum state transmission is a prerequisite for various quantum communication networks. The channel noise inevitably introduces distortion of quantum states passing through either a free-space channel or a fibre channel, which leads to errors or decreases the security of a practical quantum communication network. Quantum error rejection is a useful technology to faithfully transmit quantum states over large-scale quantum channels. It provides the communication parties with an uncorrupted quantum state by rejecting error states. Usually, additional photons or degrees of freedom are required to overcome the adverse effects of channel noise. As quantum error rejection method consumes less quantum resource than other anti-noise methods, it is more convenient to perform error-rejection quantum state transmission with current technology. In this review, several typical quantum errorrejection schemes for single-photon state transmission are introduced in brief and some error-rejection schemes for entanglement distribution are also briefly presented.

部分预成核以制备单相基于FA0.92MA0.08PbI3的高效太阳电池（英文）

目前为止,对于高性能钙钛矿太阳能电池(PSCs)的开发已经进行了大量的研究,并取得了显著的成果.基于FAxMA1-xPbI3的混合阳离子钙钛矿具有广泛的吸光范围和显著的热稳定性,是获得高性能器件的理想材料.然而,很难通过前驱体来控制钙钛矿膜中混合阳离子的比例.此外,高MA+含量的FAxMA1-xPbI3薄膜存在严重的相分离和大量的陷阱态,导致光伏性能较差.为了抑制相分离,本文提出了一种退火前部分成核的后处理方法,用混合的甲酰胺碘/甲铵碘(FAI/MAI)溶液处理制备的FAI-Pb I-2-DMSO中间相,最终得到的钙钛矿为FA0.92MA0.08PbI3.发现由于类似的分子结构引发了钙钛矿后处理薄膜中的离子交换,从而促进了部分成核,缺陷大大减少.因此,增加的光捕获和减少的缺陷态有助于提高开路电压和短路电流.用后处理方法制备的PSCs在大气条件下,最大PCE为20.80%, 80天后降解率为30%,具有可靠的重现性.

Synergy and Redundancy in a Signaling Cascade with Different Feedback Mechanisms

Feedback plays an important role in various biological signal transmission systems. In this paper, a signaling cascade system(including three layers: input(S), intermediate(V), output(X) components) is employed to study the fluctuations and net synergy in information transmission, in which the V component is regulated by itself or the X component, and each feedback on V is either positive or negative. The Fano factor, the net synergy, and the signalto-noise ratio(SNR) of signaling cascade with the four possible feedback types are theoretically derived by using linear noise approximation of the master equation, and the ability of information transmission through the signaling cascade is characterized by using the partial information decomposition of information theory. It is found that the signaling cascade exhibits different responses to the four feedback mechanisms, which depend on the relationships between degradation rates of components. Our results not only clarify the dependence of the Fano factor, net synergy, and SNR on the feedback regulations with the varying of degradation rates of components, but also imply that living cells could utilize different feedback mechanisms to adapt to the external fluctuating environments.

High-capacity quantum secure direct communication with two-photon six-qubit hyperentangled states

This study proposes the first high-capacity quantum secure direct communication(QSDC) with two-photon six-qubit hyperentangled Bell states in two longitudinal momentum and polarization degrees of freedom(DOFs) of photon pairs, which can be generated using two 0.5 mm-thick type-I β barium borate crystal slabs aligned one behind the other and an eight-hole screen. The secret message can be independently encoded on the photon pairs with 64 unitary operations in all three DOFs. This protocol has a higher capacity than previous QSDC protocols because each photon pair can carry 6 bits of information, not just 2 or 4 bits.Our QSDC protocol decreases the influence of decoherence from environment noise by exploiting the decoy photons to check the security of the transmission of the first photon sequence. Compared with two-way QSDC protocols, our QSDC protocol is immune to an attack by an eavesdropper using Trojan horse attack strategies because it is a one-way quantum communication.The QSDC protocol has good applications in the future quantum communication because of all these features.