A Tri-Salt Composite Electrolyte with Temperature Switch Function for Intelligently Temperature-Controlled Lithium Batteries

The intense research of lithium-ion batteries has been motivated by their successful applications in mobile devices and electronic vehicles.The emerging of intelligent control in kinds of devices brings new requirements for battery systems.The high-energy lithium batteries are expected to respond or react under different environmental conditions.In this work,a tri-salt composite electrolyte is designed with a temperature switch function for intelligently temperature-controlled lithium batteries.Specifically,the halide Li_(3)YBr_(6)together with LiTFSI and LiNO_(3)works as active fillers in a low-melting-point polymer matrix(polyethyleneglycol dimethyl ether(PEGDME)and polyethylene oxide(PEO)),which is further filled into the pre-lithiated alumina fiber skeleton.Above 60°C,the composite electrolyte exists in the liquid state and fully contacts with the working electrodes on the liquid–solid interface,effectively minimizing the interfacial resistance and leading to high discharge capacity in the cell.The electrolyte is changed into a solid state below 30°C so that the ionic conductivity is significantly reduced and the interface resistance is increased dramatically on the solid–solid interface.Therefore,by simply adjusting the temperature,the cell can be turned“ON”or“OFF”intentionally.This novel function of the composite electrolyte has enlightening significance in developing intelligently temperature-controlled lithium batteries.

Estimation of enhanced low dose rate sensitivity mechanisms using temperature switching irradiation on gate-controlled lateral PNP transistor

The mechanisms occurring when the switched temperature technique is applied,as an accelerated enhanced low dose rate sensitivity(ELDRS)test technique,are investigated in terms of a specially designed gate-controlled lateral PNP transistor(GLPNP)that used to extract the interface traps(Nit)and oxide trapped charges(Not).Electrical characteristics in GLPNP transistors induced by ^(60)Co gamma irradiation are measured in situ as a function of total dose,showing that generation of Nit in the oxide is the primary cause of base current variations for the GLPNP.Based on the analysis of the variations of Nit and Not,with switching the temperature,the properties of accelerated protons release and suppressed protons loss play critical roles in determining the increased Nit formation leading to the base current degradation with dose accumulation.Simultaneously the hydrogen cracking mechanisms responsible for additional protons release are related to the neutralization of Not extending enhanced Nit buildup.In this study the switched temperature irradiation has been employed to conservatively estimate the ELDRS of GLPNP,which provides us with a new insight into the test technique for ELDRS.

Multifunctional disk device for optical switch and temperature sensor

A multifunctional surface plasmon polariton disk device coupled by two metal-insulator-metal（MIM） waveguides is proposed and investigated numerically with finite-difference time-domain simulation. It can be used as optical switch and temperature sensor by filling disk with liquid crystal and ethanol, respectively. The simulation results demonstrate that the transmission characteristics of an optical switch can be manipulated by adjusting the radius of disk and the slit width between disk and MIM waveguides. The transmittance and modulation depth of optical switch at 1550 nm are up to 64.82% and 17.70 d B, respectively. As a temperature sensor, its figure of merit can reach 30.46. In this paper, an optical switch with better efficiency and a temperature sensor with better sensitivity can be achieved.

Multifunctional interlayer with simultaneously capturing and catalytically converting polysulfides for boosting safety and performance of lithium-sulfur batteries at high-low temperatures

Lithium-sulfur(Li-S) batteries as extremely promising high-density energy storage devices have attracted extensive concern. However, practical applications of Li-S batteries are severely restricted by not only intrinsic polysulfides shuttle resulting from their concentration gradient diffusion and sluggish conversion kinetics but also serious safety issue caused by thermolabile and combustible polymer separators.Herein, it is presented for the first time that a robust and multifunctional separator with urchin-like Co-doped Fe OOH microspheres and multiwalled carbon nanotubes(MWCNTs) as an interlayer simultaneously achieves to suppress polysulfides shuttle as well as improves thermotolerance and nonflammability of commercial PP separator. Accordingly, Li-S batteries with modified separator exhibit remarkable performance in a wide range temperatures of-25–100 ℃. Typically, under 25 ℃, ultrahigh initial capacities of 1441 and 827.29 m A h g-1 at 1 C and 2 C are delivered, and remained capacities of 936 and 663.18 mA h g-1 can be obtained after 500 cycles, respectively. At 0.1 C, the S utilization can reach up to 97%. Significantly, at 1 C, the batteries also deliver an excellent performance with remained capacities of high to862.3, 608.4 and 420.6 m A h g-1 after 100, 300 and 450 cycles under 75, 0 and-25 ℃, respectively. This work provides a new insight for developing stable and safe high-performance Li-S batteries.

A feedback-controlled Brownian ratchet operated by a temperature switch

In this paper, we present a model of the Brownian motor in a feedback controlled ratchet, in which the application of the flashing potential depends on the state of the particle to be controlled. We derive an analytical expression for the velocity induced by the feedback ratchet, which is a function of several parameters, including the ratio of the two switching temperatures and the asymmetry parameter of the potential field. The motor shows a current inversion when either parameter is varied.

Room Temperature Phosphorescence pH Switch Based on Photo-induced Electron Transfer

In this paper, photoinduced electron transfer(PET) phosphoroionophore, N-(1-bromo- 2-naphthylmethyl)-diethanolamine (BND) was synthesized and its phosphorescent characteristics were studied. The experimental results showed that strong phosphorescence could be observed in b-cyclodextrin aqueous solution only at low pH value. This system combined AND and NOT function to produce a three-input inhibit (INH) logic gate.

Optimization on temperature efficiency and switch time of thin-walled regenerator with perturbation analysis

The heat transfer characteristic of honeycomb ceramic regenerator was optimized by the perturbation analytical-numerical method. The results show that there is a temperature efficiency peak and the corresponding optimal switch time. The decrease of air oxygen concentration leads to the decrease of maximum temperature efficiency. Optimal switch time is directly proportional to the matrix thickness. The solid heat conduction along the flow direction and the regenerator heat storage capacity of the unit volume have no impact on maximum temperature efficiency and optimal switch time. The temperature efficiency tendency based on the semi-analysis is the same as dispersion combustion tests with low oxygen concentration, and optimal switch time of 2-4 s agrees well with that of 4 s in high-temperature gasification tests. The possibility of design, operate and control a thin-walled regenerator with high efficiency by means of the perturbation method is proved.

Induced current of high temperature superconducting loops by combination of exciting coil and thermal switch

With its commercialization, the second-generation(2G) high temperature superconducting(HTS) RE–Ba–Cu–O(REBCO, RE is rare earth) tape is extensively applied to the superconducting magnets in the high magnetic fields. However,unlike low temperature superconducting(LTS) magnets, the HTS magnet cannot operate in the persistent current mode(PCM) due to the immature superconducting soldering technique. In this paper, an exciting method for two HTS sub-loops,so-called charging and load loops, is proposed by flux pump consisting of exciting coil and controllable thermal switch.Two HTS sub-loops are made of an REBCO tape with two slits. An exciting coil with iron core is located in one sub-loop and is supplied with a triangular waveform current so that magnetic field is generated in another sub-loop. The influence of magnetic flux on induced current in load loop is presented and verified in experiment at 77 K. The relationship between the induced magnetic flux density and the current on the sub-loops having been calibrated, magnetic flux density, and induced current are obtained. The results show that the HTS sub-loops can be excited by a coil with thermal switch and the induced current increases with magnetic flux of exciting coil increasing, which is promising for persistent current operation mode of HTS magnets.

Frequency Switches at Transition Temperature in Voltage-Gated Ion Channel Dynamics of Neural Oscillators

Understanding of the mechanisms of neural phase transitions is crucial for clarifying cognitive processes in the brain. We investigate a neural oscillator that undergoes different bifurcation transitions from the big saddle homoclinic orbit type to the saddle node on an invariant circle type, and the saddle node on an invariant circle type to the small saddle homoclinic orbit type. The bifurcation transitions are accompanied by an increase in thermodynamic temperature that affects the voltage-gated ion channel in the neural oscillator. We show that nonlinear and thermodynamical mechanisms are responsible for different switches of the frequency in the neural oscillator. We report a dynamical role of the phase response curve in switches of the frequency, in terms of slopes of frequency-temperature curve at each bifurcation transition. Adopting the transition state theory of voltagegated ion channel dynamics, we confirm that switches of the frequency occur in the first-order phase transition temperature states and exhibit different features of their potential energy derivatives in the ion channel. Each bifurcation transition also creates a discontinuity in the Arrhenius plot used to compute the time constant of the ion channel.

Numerical Study of Transient Temperature Distribution in Passively Q-Switched Yb:YAG Solid-State Laser

In this work, the thermal characterization of continuously pumped passively Q-switched laser is quantitatively represented. The system under investigation is end-pumped Yb:YAG passively Q-switched by Cr4+:YAG as saturable absorber. The rate equations describing the dynamics of laser action are numerically solved simultaneously with the temperature conductivity heat equation to depict the transient temperature distribution. The study has been performed in the cylindrical coordinates to characterize the temperature distribution in the axial and radial directions. The thermal transient time in both directions as well as the thermal focal length are calculated. The temporal behavior of the temperature distribution has been illustrated in a 3-dimensional diagram.

Investigation of a CO2 Switching Arc Using Spectroscopic Diagnostics and Computational Fluid Dynamics Simulations

A deep understanding of the physical processes coming along with the current interruption in high voltage circuit breakers is essential for the optimization of today’s switching technologies.Therefore a switching arc in a model circuit breaker is studied by means of computational fluid dynamics(CFD)simulations and optical emission spectroscopy(OES)in this contribution.Experimental investigations are performed in carbon dioxide(CO2)at absolute filling pressures of 0.1 and 0.5 MPa.CFD simulations are carried out based on a model of the arcing zone including a consistent treatment of the radiation transport and the wall ablation.Carbon ion line radiation is analysed in the experiment using an optical path in the heating channel between the electrodes inside the nozzle system.The pressure value in the arc is estimated based on the line width-intensity dependence.Obtained values correspond to the measured pressure outside the arc.For the temperature profiles,a good agreement within the accuracy of the approaches is observed between the CFD simulations and the results of OES.

Structure and switching of single-stranded DNA tethered to a charged nanoparticle surface

Using a molecular theory, we investigate the temperature-dependent self-assembly of single-stranded DNA（ss DNA）tethered to a charged nanoparticle surface. Here the size, conformations, and charge properties of ss DNA are taken into account. The main results are as follows： i） when the temperature is lower than the critical switching temperature, the ss DNA will collapse due to the existence of electrostatic interaction between ss DNA and charged nanoparticle surface; ii）for the short ss DNA chains with the number of bases less than 10, the switching of ss DNA cannot happen, and the critical temperature does not exist; iii） when the temperature increases, the electrostatic attractive interaction between ss DNA and charged nanoparticle surface becomes weak dramatically, and ss DNA chains will stretch if the electrostatic attractive interaction is insufficient to overcome the elastic energy of ss DNA and the electrostatic repulsion energy. These findings accord well with the experimental observations. It is predicted that the switching of ss DNA will not happen if the grafting densities are too high.

High Temperature Superconducting Magnetic Energy Storage and Its Power Control Technology

High temperature superconducting （HTS） power inductor and its control technology have been studied and analyzed in the paper. Based on the results of simulations and practical experiments, a controlled release scheme has been proposed and verified for developing a practical HTS SMES prototype.

并联IGBT占空比的温度特性建模与分析

并联IGBT是解决托卡马克(Tokamak)装置中等离子体垂直位移快速控制电源容量逐渐增大问题的有效途径。而并联IGBT之间的结温平衡是并联系统安全稳定运行的关键因素之一。因此,研究结温对并联IGBT功率损耗差异的影响对提高并联系统的稳定性至关重要。然而现有的研究成果主要集中在单个器件损耗模型或者是并联IGBT的最佳工作频率范围而未涉及对并联IGBT最佳工作占空比范围的讨论。研究发现,当IGBT工作在正温度系数区间时,结温差异造成的通态损耗差异与开关损耗差异呈不同的温度特性。因此,提出零温度-占空比的概念来估计并联IGBT之间结温失配趋势。该文建立零温度-占空比模型,并以此来分析电路设计参数、IGBT器件参数以及结温差异对并联IGBT最佳工作占空比范围的影响。实验结果表明,通过零温度-占空比模型可以对并联IGBT的可靠性、电路设计参数以及器件选型提供可行的参考。

一种基于HTCC的高隔离度开关电路设计

基于开关芯片实现的开关电路是射频前端的基本单元之一,其功能是实现射频信号的导通和关断,在小功率射频信号传输中应用广泛。本文以6 GHz~15 GHz超宽带、60 dB隔离度为设计目标,采用高温共烧陶瓷基板工艺和级联腔体隔离技术,以级联开关芯片为基本电路结构,设计了高隔离度开关电路。该电路包含一只限幅器和两只吸收式砷化镓单刀单掷开关,装配于两个相邻的隔离腔体结构中,通过类同轴垂直传输过渡到基板内对称带状线传输结构,再辅以两侧地孔,实现电磁屏蔽。对开关电路进行电磁场建模仿真,结果表明该结构具有良好的传输特性和隔离特性;在射频前端电路制造完成后对开关电路进行装配和测试,测试结果与建模仿真结果一致性高,验证了本文设计的开关电路具有高隔离度特性。

脉冲晶闸管热网络模型及运行状态评估方法

针对脉冲晶闸管承受强流脉冲导致的瞬态电磁热力联合冲击产生的热疲劳累积突发性失效问题,提出了在脉冲晶闸管内布置温度传感器的状态监测方法,建立了脉冲晶闸管的高阶瞬态热阻抗网络模型,分析了强流脉冲作用下脉冲晶闸管内部不同层的温度分布规律,并通过理论计算验证了分析方法的有效性。计算结果表明,热网络模型计算相对偏差小于5%。可为脉冲晶闸管型强流开关的状态评估提供理论指导。

涂层传热性能对母线散热能力影响分析

为提升电力开关柜散热性能、提高供配电稳定性,本文依据传热学基础理论对电力开关柜传热过程进行分析,采用溶液共混法成功制备了适用于电力开关柜母线散热的涂层材料,并基于电磁-热-流多物理场耦合原理构建了电力开关柜涂层-热分析模型,结合母线负载电流计算理论,从涂层热导率、发射率等方面对涂覆散热涂层前后的电力开关柜传热特性进行分析。结果表明:涂层热导率相比于涂层发射率对母线温升影响较小,母线表面涂覆涂层之后,B相母线表面发射率由0.2增大到0.846时,三相母线最大负载电流与未涂覆相比提升18.75%。

低压开关柜中温升监测装置的应用分析

旨在研究低压开关柜的温升监测装置设计与应用,考虑到开关柜结构复杂、部件温度过高可能导致过热故障的问题。通过研究发现,温升在线监测装置能够有效感知开关柜内零部件温度变化,为控制温度提供有力支持。设计包括远红外测温技术、数据采集模块、上位机软件以及报警系统的综合应用,以全面监测开关柜区域。通过大数据和计算机技术分析温度变化数据,预防过热故障的发生,提高设备可靠性,延长寿命,对电力系统的稳定运行具有积极意义。

双面散热SiC功率模块温度均匀性和开关特性评估

碳化硅MOSFET因其材料特性被广泛应用于新能源汽车的高压、高频和高功率密度场合。在考虑双面水冷散热过程,往往忽略芯片布局间距对于散热以及芯片温度均匀性的影响,未考虑芯片温度均匀性对于多芯片并联电流均匀性的影响。针对上述问题,设计一种双面水冷的封装结构,分析不同芯片布局间距对芯片温度均匀性的影响,分析不同结温及不同芯片布局对寄生参数及开关特性的影响,并针对不同芯片布局间距和不同液冷工况,采用大量仿真及响应面对比分析,验证了所提方法的有效性,为SiC功率模块封装对芯片温度均匀性及开关特性的影响提供技术方法指导和定量分析。

双波长LD泵浦Nd^(3+)∶YAG免温控被动调Q激光器的研究

传统的固体激光器体积、重量大,功耗高,限制了其在空间受限设备中的应用。被动调Q的LD泵浦免温控固体激光器省去了复杂的温度控制装置,调Q机构简单,能够满足复杂温度环境的特殊应用场景的小型化、低功耗要求。提出了基于双波长LD泵浦实现宽温度范围免温控阈值自适应的1.06μm激光脉冲输出方法。基于Nd∶YAG晶体设计了角锥棱镜谐振腔,仿真分析了LD泵浦源到激光棒的面心距对热负载的影响,并确定4 mm的最佳面心距。数值分析了相同泵浦功率下-40~60℃温度范围内激光静态能量输出变化,以及不同初始透过率的可饱和吸收体对激光阈值脉宽的影响。计算结果表明在-37℃~60℃范围内,阈值脉宽都在200μs以下,阈值脉宽最低点达到了29.4μs。构建主波实时探测的阈值自适应调节装置并搭建实验系统,实验结果表明,在温度范围为-35~60℃时,阈值脉宽变化范围为40~180μs。采用激光腔体一体加工成型,应用轻量化的铝合金材料,实现工程化应用,体积83.5 mm×44 mm×29.5 mm,重量约为230 g。在23.8%初始透过率的饱和吸收体条件下实现单脉冲输出能量42 mJ,脉冲宽度5.2 ns。