Colorless to black switching with high contrast ratio via the electrochemical process of a hybrid organic-inorganic perovskite

Colorless‐to‐black switching has attracted widespread attention for smart windows and multifunctional displays because they are more useful to control solar energy.However,it still remains a challenge owing to the tremendous difficulties in the design of completely reverse absorptions in transmissive and colored states.Herein,we report on an electrochemical device that can switch between colorless and black by using the electrochemical process of hybrid organic–inorganic perovskite MAPbBr_(3),which shows a high integrated contrast ratio of up to 73%from 400 to 800 nm.The perovskite solution can be used as the active layer to assemble the device,showing superior transmittance over the entire visible region in neutral states.By applying an appropriate voltage,the device undergoes reversible switching between colorless and black,which is attributed to the formation of lead and Br_(2)in the redox reaction induced by the electron transfer process in MAPbBr_(3).In addition,the contrast ratio can be modulated over the entire visible region by changing the concentration and the applied voltage.These results contribute toward gaining an insightful understanding of the electrochemical process of perovskites and greatly promoting the development of switchable devices.

Temperature dependence of multi-jump magnetic switching process in epitaxial Fe/MgO(001) films

Temperature dependence of magnetic switching processes with multiple jumps in Fe/MgO（001） films is investigated by magnetoresistance measurements. When the temperature decreases from 300K to 80K, the measured three-jump hysteresis loops turn into two-jump loops. The temperature dependence of the fourfold in-plane magnetic anisotropy constant K1, domain wall pinning energy, and an additional uniaxial magnetic anisotropy constant KUare responsible for this transformation. The strengths of K1 and domain wall pinning energy increase with decreasing temperature, but KU remains unchanged. Moreover, magnetization reversal mechanisms, with either two successive or two separate 90°domain wall propagation, are introduced to explain the multi-jump magnetic switching process in epitaxial Fe/MgO（001） films at different temperatures.

Markov repairable systems with stochastic regimes switching

Compared with the classical Markov repairable system, the Markov repairable system with stochastic regimes switching introduced in the paper provides a more realistic description of the practical system. The system can be used to model the dynamics of a repairable system whose performance regimes switch according to the external conditions. For example, to satisfy the demand variation that is typical for the power and communication systems and reduce the cost, these systems usually adjust their operating regimes. The transition rate matrices under distinct operating regimes are assumed to be different and the sojourn times in distinct regimes are governed by a finite state Markov chain. By using the theory of Markov process, Ion channel theory, and Laplace transforms, the up time of the system are studied. A numerical example is given to illustrate the obtained results. The effect of sojourn times in distinct regimes on the availability and the up time are also discussed in the numerical example.

Resistive Switching Memory of TiO2 Nanowire Networks Grown on Ti Foil by a Single Hydrothermal Method

The resistive switching characteristics of TiO_2 nanowire networks directly grown on Ti foil by a single-step hydrothermal technique are discussed in this paper. The Ti foil serves as the supply of Ti atoms for growth of the TiO_2 nanowires, making the preparation straightforward. It also acts as a bottom electrode for the device. A top Al electrode was fabricated by e-beam evaporation process. The Al/TiO_2 nanowire networks/Ti device fabricated in this way displayed a highly repeatable and electroforming-free bipolar resistive behavior with retention for more than 10~4 s and an OFF/ON ratio of approximately 70. The switching mechanism of this Al/TiO_2 nanowire networks/Ti device is suggested to arise from the migration of oxygen vacancies under applied electric field. This provides a facile way to obtain metal oxide nanowire-based Re RAM device in the future.

The Switching Fractional Order Chaotic System and Its Application to Image Encryption

Many studies on fractional order chaotic systems and secure communications have been carried out, however, switching fractional order chaotic system and its application to image encryption have not been explored yet. In this paper, a new switching fractional order chaotic system is proposed, containing fractional order Chen system and the other two fractional order chaotic systems. Chaotic attractors and dynamical analysis including Lyapunov exponent, bifurcation diagram, fractal dimension, dissipation, stability and symmetry are shown firstly. After that, some circuit simulations through Multisim are presented. By controlling switch k U+2082 and k U+2083, switching among the three fractional order chaotic subsystems can be realized. Finally, we apply the switching fractional order chaotic system to image encryption using exclusive or U+0028 XOR U+0029 encryption algorithm. The encryption scheme could increase randomness and improve speed of encryption. © 2017 Chinese Association of Automation.

Dynamic optimization of 1,3-propanediol fermentation process:A switched dynamical system approach

This paper considers a dynamic optimization problem(DOP)of 1,3-propanediol fermentation process(1,3-PFP).Our main contributions are as follows.Firstly,the DOP of 1,3-PFP is modeled as an optimal control problem of switched dynamical systems.Unlike the existing switched dynamical system optimal control problem,the state-dependent switching method is applied to design the switching rule.Then,in order to obtain the numerical solution,by introducing a discrete-valued function and using a relaxation technique,this problem is transformed into a nonlinear parameter optimization problem(NPOP).Although the gradient-based algorithm is very efficient for solving NPOPs,the existing algorithm is always trapped in a local minimum for such problems with multiple local minima.Next,in order to overcome this challenge,a gradient-based random search algorithm(GRSA)is proposed based on an improved gradient-based algorithm(IGA)and a novel random search algorithm(NRSA),which cannot usually be trapped in a local minimum.The convergence results are also established,and show that the GRSA is globally convergent.Finally,a DOP of 1,3-PFP is provided to illustrate the effectiveness of the GRSA proposed by this paper.

Research of Crossbar Switch of High Performance Network of Signal Processing System

The new type of embedded signal processing system based on the packet switched network is achieved. According to the application field and the-characteristics of signal processing system, the RapidIO protocol is used to solve the high-speed interconnection of multi-digital signal processor （DSP）. Based on this protocol, a kind of crossbar switch module which is used to interconnect multi-DSP in the system is introduced. A route strategy, some flow control rules and error control rules, which adapt to different RapidIO network topology are also introduced. Crossbar switch performance is analyzed in detail by the probability module. By researching the technique of crossbar switch and analyzing the system performance, it has a significant meaning for building the general signal processing system.

Informative Property of the Data Set in a Single-input Single-output (SISO) Closed-loop System with a Switching Controller

Closed-loop identification is important and necessary to various model-based advanced process control strategies, whose performance depends greatly on the informative property of the data set. Switching control is an important method in process control. Therefore, this paper studies the informative property of a data set in a single-input single-output (SISO) closed-loop system with a switching controller. It is proved that this data set is informative if the controller switches among at least two modes (i.e., feedback laws). Our result does not require any assumption on the way of switch and removes the constraints on the switching manner required in some classical literature. Finally, simulation case studies based on a continuous stirred-tank reactor (CSTR) process are given to validate the results.

Identification of key genes responsible for cytokine-induced erythroid and myeloid differentiation and switching of hematopoietic stem cells by RAGE

We utilized a unique culture system to analyze the expression patterns of gene, protein, and cell surface antigen, and the biological process of the related genes in erythroid and myeloid differentiation and switching of hematopoietic stem cells （HSCs） in response to cytokine alterations. Gene-specific fragments （266） identified from five populations of cytokine-stimulated HSCs were categorized into three groups： （1） expressed specifically in a single cell population; （2） expressed in two cell populations, and （3） expressed in three or more populations. Of 145 defined cDNAs, three （2%） were novel genes. Protein two-dimensional gel electrophoresis and flow cytometry analyses showed overlapped and distinguished protein expression profiles in the cell populations studied. Biological process mapping of mRNAs expressed in erythroid and myeloid lineages indicated that mRNAs shared by both lineages attended ＇core processes,＇ whereas genes specifically expressed in either lineage alone were related to specific processes or cellular maturation. Data from this study support the hypothesis that committed HSCs （El4 or G14） cells can still be redirected to develop into myeloid or erythroid cells when erythropoietin （EPO） is replaced with granulocyte-colony stimulating factor （G-CSF） under erythroid-cultured condition or G-CSF with EPO in myeloid-cultured environment, respectively. Our results suggest that genes or proteins co-expressed in erythroid and myeloid lineages may be essential for the lineage maintenance and switching in hematopoiesis.

基于FreeSWITCH的电话约车系统方案与应用

随着移动互联网技术的发展,智能交通出行系统日益普及,老年人等不方便使用智能手机的人群面临约车难的问题。对这一难题进行了研究,提出一种基于FreeSWITCH的电话约车方案。该方案通过对接IMS/PSTN实现全自动叫车功能,并由约车平台进行车辆调度和结果反馈。该方案操作简便、无需智能手机,提高了出行效率和便利性。实际应用案例验证了系统的可行性和实用性,为不方便使用智能手机的人群提供了便捷的出行选择。

面向下一代互联网实验平台的新型报文处理模型——EasySwitch

下一代互联网实验平台应能提供网络原型系统快速开发及部署能力,以有效支撑新型互联网体系结构关键技术的实现和验证.基于FPGA(Field Programmable Gate Array)技术构建的网络实验平台可以提供较高的可编程性和性能,而它对硬件逻辑设计能力的要求则严重限制了平台的广泛应用.新型报文处理模型EasySwitch通过优化设计并预置通用报文交换及处理逻辑,有效实现用户定制报文处理逻辑与通用报文处理逻辑解耦;良定义的用户模块接口则使用户仅需关注业务特定逻辑实现,有效简化用户逻辑设计.理论分析表明,EasySwitch可通过提供确定性资源约束模型,有效支持FPGA资源的优化利用.此外,EasySwitch具有较低的报文调度处理延迟,对实验系统输入流量真实特性影响较小.EasySwitch模型在NetMagic平台的有效实现及应用表明该模型可为下一代互联网新型报文处理机制及协议的快速设计、开发和验证提供有力支撑.

Comparative Performance Evaluation of Large FPGAs with CNFET-and CMOS-based Switches in Nanoscale

Routing resources are the major bottlenecks in improving the performance and power consumption of the current FPGAs. Recently reported researches have shown that carbon nanotube field effect transistors(CNFETs) have considerable potentials for improving the delay and power consumption of the modern FPGAs. In this paper, hybrid CNFET-CMOS architecture is presented for FPGAs and then this architecture is evaluated to be used in modern FPGAs. In addition, we have designed and parameterized the CNFET-based FPGA switches and calibrated them for being utilized in FPGAs at 45 nm, 22 nm and 16 nm technology nodes.Simulation results show that the CNFET-based FPGA switches improve the current FPGAs in terms of performance, power consumption and immunity to process and temperature variations. Simulation results and analyses also demonstrate that the performance of the FPGAs is improved about 30%, on average and the average and leakage power consumptions are reduced more than 6% and 98% respectively when the CNFET switches are used instead of MOSFET FPGA switches. Moreover, this technique leads to more than 20.31%smaller area. It is worth mentioning that the advantages of CNFET-based FPGAs are more considerable when the size of FPGAs grows and also when the technology node becomes smaller.

Switch Corridor方差互换定价的蒙特卡罗加速算法

主要研究为对冲跨市场波动率风险而开发的双标的资产的新型方差产品——Switch Corridor方差互换的定价问题。该产品由瑞士信贷(Credit Suisse)于2012年率先推出,逐渐成为了结构性产品市场上最受欢迎的新产品系列之一。使用控制变量Monte Carlo方法研究了双Heston随机波动率模型下Switch Corridor方差互换的定价问题,基于仿射结构理论,得到辅助标的过程下方差产品价格的解析解,构造了问题求解的高效控制变量。进一步地,考察了不同辅助过程波动率的选取对加速效果的影响。通过数值实验可以证明,基于动态波动率选取的辅助过程起到了很好的加速效果。该算法亦可方便地解决其他随机波动率模型下高维方差产品的计算问题。

互联网使用对稻农收入的影响研究——基于生产环节信息获取的实证

增加农民收入是我国“三农”工作的核心任务。互联网在农业主体中的普及和应用已经逐步渗透到农业生产全过程,对农民收入增长产生重要影响。以湖北省1110个水稻种植户为实证研究对象,利用内生转换模型探究农户在生产环节使用互联网获取信息对其农业收入的影响。研究结果表明:使用互联网能够显著促进农户农业收入增长。在采用替换模型方法和不同被解释变量进行再估计后,结果依然稳健。机制分析显示,互联网使用通过提升农户生产技术效率、土地生产率和劳动生产率实现农业收入的增长。此外,互联网使用对人力资本水平高、家庭经营土地规模大、初始农业收入高的农户增收效果更为明显。因此,政府应通过以下措施助力农户利用互联网增收:继续加快数字乡村建设,完善农村互联网基础设施,推进互联网在涉农主体中的普及和应用;开展基础教育与技能培训;对低收入群体提供精准信息供给服务,推进信息资源下沉。

特快速空间辐射暂态电磁场测量装置研究

为研究隔离开关操作条件下GIS的瞬态辐射电磁场特性,该文开展特快速高频辐射电磁场测量装置的研制。开关操作辐射电磁场具有上升陡度大、幅值高、频带宽等特点,因此该文选择双锥天线和电小环天线进行电场和磁场的测量,设计特快速辐射电场、磁场与VFTO联合测量方案。通过特快速高频辐射电磁场测量装置对550 kV GIS试验平台隔离开关操作产生的特快速辐射电场、磁场进行测量。结果表明:开关操作时GIS变电站电磁环境极其恶劣,分闸时电场强度可达3.5 kV/m,磁场强度可达220 A/m;合闸时电场强度为2.5 kV/m,磁场强度为150 A/m。单次脉冲持续时间约5μs,主要频率成分为8 MHz,46 MHz,58 MHz。

半隐式延迟解耦的开关动作高效处理方法

传统电磁暂态仿真采用详细模型建模电压源型换流器(voltage source converter,VSC)并采用双插值法(double interpolation method,DIM)处理步长内的开关事件,由于详细模型的导纳阵时变,DIM算法流程复杂,在进行大电网仿真时严重影响计算效率。针对这一问题,应用半隐式延时解耦原理建模VSC,并对步长内开关事件的处理方法进行研究,通过对开关函数在步长内的占空比进行等值代替DIM,提高仿真效率。首先,从VSC状态方程出发,得到VSC解耦模型,实现换流器的并行计算,提高计算效率;其次,分析了不处理开关事件时累计误差的产生机理,并给出了计算时序和开关函数等值占空比的计算方法,保证仿真精度;最后,以PSCAD的仿真波形为基准,验证了所提方法的精度和有效性,讨论了所提方法的方法特点。

10.4~28 GHz的超宽带6位数字衰减器设计

基于中芯国际40 nm CMOS工艺设计并实现了一种超宽带6位数字衰减器,其工作频率为10.4~28 GHz。该衰减器采用内嵌式开关型结构,6位衰减单元的设计采用T型、桥T型和π型三种拓扑结构。该6位衰减器可以实现0.5 dB的衰减步进,31.5 dB的动态衰减范围。采用大衰减量幅度补偿电路和高匹配特性的衰减位级联结构,衰减器在10.4~28 GHz的频段范围内具有平坦的64态衰减量,衰减器的整体前仿真插入损耗为1.73~2.08 dB,后仿真插入损耗为4.32~6.31 dB,64态的输入输出回波损耗均小于-10 dB。

霍尔电推进PPU阳极电源拓扑技术研究

针对未来对大功率以及超大功率电源处理单元的需求,对国内外霍尔推力器阳极电源拓扑技术的研究现状进行了分析与总结,采用软开关四管Buck-Boost变换器的PWM加移相控制策略,结合对该策略的时序仿真分析试验,对传统“四边形电感电流”模式进行了改进,解决了电路工作在低负载情况下时,整个电路会因开关管的额外损耗导致变换器的效率降低的问题,使电路在全电压全负载范围内实现了开关管的零电压开通,将电感电流的有效值降到了最小,在极大地降低了开关管造成的损耗的同时提升了四管Buck-Boost变换器效率。

Successful couplings for difusion processes with state-dependent switching

This work is concerned with successful couplings for a class of multidimensional diffusion processes with state-dependent switching. We construct a type of couplings for this class of processes, and give some sufficient conditions to guarantee this type of couplings to be successful. Besides, two illustrative examples are provided.