Exploring device physics of perovskite solar cell via machine learning with limited samples

Perovskite solar cells(PsCs)have developed tremendously over the past decade.However,the key factors influencing the power conversion efficiency(PCE)of PSCs remain incompletely understood,due to the complexity and coupling of these structural and compositional parameters.In this research,we demon-strate an effective approach to optimize PSCs performance via machine learning(ML).To address chal-lenges posed by limited samples,we propose a feature mask(FM)method,which augments training samples through feature transformation rather than synthetic data.Using this approach,squeeze-and-excitation residual network(SEResNet)model achieves an accuracy with a root-mean-square-error(RMSE)of 0.833%and a Pearson's correlation coefficient(r)of 0.980.Furthermore,we employ the permu-tation importance(PI)algorithm to investigate key features for PCE.Subsequently,we predict PCE through high-throughput screenings,in which we study the relationship between PCE and chemical com-positions.After that,we conduct experiments to validate the consistency between predicted results by ML and experimental results.In this work,ML demonstrates the capability to predict device performance,extract key parameters from complex systems,and accelerate the transition from laboratory findings to commercialapplications.

Recent developments in superjunction power devices

Superjunction(SJ)is one of the most innovative concepts in the field of power semiconductor devices and is often referred to as a"milestone"in power MOS.Its balanced charge field modulation mechanism breaks through the strong dependency between the doping concentration in the drift region and the breakdown voltage V_(B)in conventional devices.This results in a reduction of the trade-off relationship between specific on-resistance R_(on,sp)and V_(B)from the conventional R_(on,sp)∝V_(B)^(2.5)to R_(on,sp)∝W·V_(B)^(1.32),and even to R_(on,sp)∝W·V_(B)^(1.03).As the exponential term coefficient decreases,R_(on,sp)decreases with the cell width W,exhibiting a development pattern reminiscent of"Moore's Law".This paper provides an overview of the latest research developments in SJ power semiconductor devices.Firstly,it introduces the minimum specific on-resistance R_(on,min)theory of SJ devices,along with its combination with special effects like 3-D depletion and tunneling,discussing the development of R_(on,min)theory in the wide bandgap SJ field.Subsequently,it discusses the latest advancements in silicon-based and wide bandgap SJ power devices.Finally,it introduces the homogenization field(HOF)and high-K voltage-sustaining layers derived from the concept of SJ charge balance.SJ has made significant progress in device performance,reliability,and integration,and in the future,it will continue to evolve through deeper integration with different materials,processes,and packaging technologies,enhancing the overall performance of semiconductor power devices.

A research on the effect of plasma spectrum collection device on LIBS spectral intensity

Only a small amount of spectral information is collected because the collection solid angle of the optical fiber probe and lens is very limited when collecting spectral information.To overcome this limitation,this study presents a novel method for acquiring plasma spectral information from various spatial directions.A parabolic-shaped plasma spectral collection device(PSCD)is employed to effectively collect more spectral information into the spectrometer,thereby enhancing the overall spectral intensity.The research objects in this study were soil samples containing different concentrations of heavy metals Pb,Cr,and Cd.The results indicate that the PSCD significantly enhances the spectral signal,with an enhancement rate of up to 45%.Moreover,the signal-to-noise ratio also increases by as much as 36%.Simultaneously,when compared to the absence of a device,it is found that there is no significant variation in plasma temperature when the PSCD is utilized.This observation eliminates the impact of the spatial effect caused by the PSCD on the spectral intensity.Consequently,a concentrationspectral intensity relationship curve is established under the PSCD.The results revealed that the linear fitting R^(2)for Pb,Cr,and Cd increased by 0.011,0.001,and 0.054,respectively.Additionally,the limit of detection(LOD)decreased by 0.361 ppm,0.901 ppm,and 0.602 ppm,respectively.These findings indicate that the spectral enhancement rate elevates with the increase in heavy metal concentration.Hence,the PSCD can effectively enhance the spectral intensity and reduce the detection limit of heavy metals in soil.

Charge transport properties and variable photo-switching of three-terminal Cs_(2)AgBiBr_(6) device

In this study,we present an in-depth exploration of charge transport phenomena and variable photo-switching characteristics in a novel double-perovskite-based three-terminal device.The Cs_(2)AgBiBr_(6) thin film(TF)was synthesized through a three-step thermal evaporation process followed by precise open-air annealing,ensuring superior film quality as confirmed by structural and morphological characterizations.Photoluminescence spectroscopy revealed distinct emissions at 2.28 and 2.07 eV,indicative of both direct and indirect electronic transitions.Our device exhibited space-charge limited current(SCLC)behaviour beyond 0.35 V,aligning with the relationship Current(I)∝Voltage(V)^(m),where the exponent m transitioned from≤1 to>1.Detailed analysis of Schottky parameters within the trap-filled limit(TFL)regime was conducted,accounting for variations in temperature and optical power.Significantly,the self-powered photodetector demonstrated outstanding performance under illumination.The sensitivity of the device was finely tunable via the applied bias voltages at the third terminal.Notably,an optimal bias voltage of±100μV yielded maximum responsivity(R)of 0.48 A/W and an impressive detectivity(D*)of 1.07×10^(9) Jones,highlighting the potential of this double-perovskite-based device for advanced optoelectronic applications.

Static Induction Devices with Planar Type Buried Gate

Based on the surface-gate and buried-gate structures,a novel buried-gate structure called the planar type buried-gate (PTBG) structure for static induction devices (SIDs) is proposed.An approach to realize a buried-gate type static induction transistor by conventional planar process technology is presented.Using this structure,it is successfully avoided the second epitaxy with a high degree of difficulty and the complicated mesa process in conventional buried gate.The experimental results demonstrate that this structure is desirable for application in power SIDs.Its advantages are high breakdown voltage and blocking gain.

Performance Limits and Advancements in Single 2D Transition Metal Dichalcogenide Transistor

Two-dimensional(2D)transition metal dichalcogenides(TMDs)allow for atomic-scale manipulation,challenging the conventional limitations of semiconductor materials.This capability may overcome the short-channel effect,sparking significant advancements in electronic devices that utilize 2D TMDs.Exploring the dimension and performance limits of transistors based on 2D TMDs has gained substantial importance.This review provides a comprehensive investigation into these limits of the single 2D-TMD transistor.It delves into the impacts of miniaturization,including the reduction of channel length,gate length,source/drain contact length,and dielectric thickness on transistor operation and performance.In addition,this review provides a detailed analysis of performance parameters such as source/drain contact resistance,subthreshold swing,hysteresis loop,carrier mobility,on/off ratio,and the development of p-type and single logic transistors.This review details the two logical expressions of the single 2D-TMD logic transistor,including current and voltage.It also emphasizes the role of 2D TMD-based transistors as memory devices,focusing on enhancing memory operation speed,endurance,data retention,and extinction ratio,as well as reducing energy consumption in memory devices functioning as artificial synapses.This review demonstrates the two calculating methods for dynamic energy consumption of 2D synaptic devices.This review not only summarizes the current state of the art in this field but also highlights potential future research directions and applications.It underscores the anticipated challenges,opportunities,and potential solutions in navigating the dimension and performance boundaries of 2D transistors.

Research on Nonlinear Dynamic Characteristics ofStructures Supported on Slide-Limited Friction Base Isolation System

This paper presents a new type of base isolation system, i. e. , slide-limited friction (S-LF) base isolation system . Based on this system, the harmonic and subharmonic periodic response of S-LF subjected to harmonic motions is investigated by using Fourier-Galerkin-Newton (FGN) method with Flo-quet theory. The dynamic response of S-LF subjected to earthquake ground motions is calculated with a high order precision direct integration method, and the numerical results are presented in maximum acceleration response spectra of superstructure and maximum sliding displacement response spectrum form. The comparison of isolating effects of S-LF, pure-friction base isolation system (P-F) and resilient-friction base isolation system (R-FBI) shows that the isolating property of S-LF is superior to those of P-F and R-FBI. Finally, by analyzing an engineering example, it is observed that the distribution of the maximum shear between floors and absolute acceleration of S-LF to earthquake ground motion is very different from that of traditional structures.

基于有限单元法驾驶室防翻保护结构性能分析

防滚翻保护装置(ROPS)设计的可靠性,直接影响驾驶员是否能得到有效的保护。根据实车尺寸和视野要求,进行ROPS结构设计和挠曲极限量DLV设计;利用UG建立驾驶室三维模型,并建立有限元分析模型;根据国家标准关于ROPS的规定,对驾驶室翻滚保护的安全性进行分析,重点对不同方向的承载进行分析;基于驾驶室翻滚测试试验台,选取侧向加载进行测试,验证模型分析的可靠性。结果可知:当侧向力增加到140kN时,驾驶室吸收的能量为16672J,满足最小能量吸收能力要求;侧向载荷加载时,应力和位移均出现最大值,分别为372MPa和11.86mm,满足材料承载和能量加载要求;试验获得侧向加载时的最大应力和最大位移,满足材料和设计尺寸的要求,且与仿真结果的误差均小于4%,表明仿真分析模型是可靠的。所设计的防翻保护装置可以起到保护作用,为此类设计生产提供参考。

起重机高度限位关键部件有限元分析

本文针对典型起重机高度限位——断火器装置和齿轮传动限制器,分别建立CAD几何模型,运用有限元方法,仿真装置运行过程,获取运行过程中关键机构、部件及零件的承载受力,通过可靠性影响因素分析,获取不同影响因素对装置可靠性影响,并提出相关意见建议。

计及柔性限流装置与直流断路器协同动作的电弧抑制暂态特性研究

直流系统的故障隔离是保证直流系统稳定运行的重要技术。针对传统故障隔离策略对直流断路器(direct current circuit breaker, DCCB)的性能要求较高的问题,提出了一种利用柔性限流装置(flexible current limiting device,FCLD)与DCCB协同动作的故障隔离策略。首先,研究了直流系统永久性故障和瞬时性故障情况下FCLD与DCCB的协同作用机理。其次,分析考虑FCLD电流抑制作用下DCCB开断过程的电弧暂态特性。最后,在Matlab/Simulink平台中进行仿真,验证所提协同策略的可行性。结果表明:FCLD可有效抑制DCCB的开断电弧;基于所提故障隔离策略,直流系统可在瞬时故障情况下实现平稳穿越,永久故障情况下实现DCCB的无弧开断。该策略降低了直流系统故障隔离过程中对DCCB的开断要求,提升了直流系统的故障穿越能力。

FX高速包装机成品烟条输送装置的设计与应用

为解决FX高速包装机成品烟条输送过程中损耗高的问题,设计一种新的成品烟条输送装置。该装置主要由变频电机、输送链板、限位装置及下滑装置4个部分组成,通过传感器监控成品烟条的运输过程,出现成品烟条堵塞时立即停止包装机和输送链板,并实时调整变频电机的速度,实现成品烟条的均匀运输,减少停机次数;通过限位装置对成品烟条进行平衡、减速,保证成品烟条在下滑装置的运输过程中保持稳定,降低成品烟条的损耗。以某卷烟厂生产的实际为对象对该装置进行测试,结果表明,应用后成品烟条损耗降低30%,成品烟条滑落和掉落的问题降低到0,运输过程中成品烟条堵塞的次数减少70%,为提高FX高速包装机的高生产效率提供保障。

国内典型残膜捡拾装置应用分析及建议

覆膜栽培种植技术发展至今在促进农作物增产增收的同时也带来不可忽视的残膜污染问题。在残膜回收作业中,残膜捡拾装置起到举足轻重的作用。为推进国内残膜回收机械领域的种类细分工作,以国内典型残膜捡拾装置为出发点,首先分别介绍搂膜弹齿排、挑膜弹齿排、残膜捡拾滚筒的工作特点,接着分别介绍各类残膜捡拾装置在残膜回收机上的应用情况,然后从捡拾装置的作业效果、作业环境及对象、装置耐用性三个方面分析现有残膜捡拾装置的应用局限性,最后结合中国残膜污染现状对残膜捡拾技术的发展提出优化结构、增强耐用性、提高信息化水平以及鼓励创新等相关建议。

骨折复位固定系统的设计和临床前研究

目的探讨骨折复位固定系统的安全性、有效性和临床应用价值。方法描述骨折复位固定系统组件克氏针限位器和克氏针导向锁紧器的设计和应用;6个医生根据手感或应用克氏针限位器在合成骨中植入克氏针,测量克氏针穿出骨的长度;克氏针导向锁紧器配合锁定板及2根直径1.5 mm克氏针、2根直径1.5 mm克氏针和2根直径2.0 mm克氏针固定合成骨构建的骨折模型,测量结构的失效扭矩。结果克氏针限位器降低了克氏针穿出骨的长度,差异有统计学意义(P<0.001),克氏针导向锁紧器配合锁定板及2根直径1.5 mm克氏针固定骨折失效扭矩高于2根直径1.5 mm克氏针和2根直径2.0 mm克氏针固定骨折(P<0.05)。结论骨折复位固定系统是提供复位和固定骨折、判断和优化锁定板螺钉位置及保护骨折块血运的新技术。

混合型限流熔断器触发装置用电流互感器铁芯结构设计

针对短路电流保护装置的电流测控单元因电子元器件失效或电源掉电而导致保护装置拒动的问题,提出了一种无源电磁式电流互感器,分析了触发装置的工作原理,根据铁芯材料的磁化特性曲线,确定了互感器有效工作区间内铁芯的最大磁感应强度。针对铁芯在大电流条件下磁通容易饱和的问题,通过仿真分析了气隙分布对互感器内磁感应强度的影响。设计出在短路电流峰值为15 kA时仍可有效工作的电磁式电流互感器铁芯结构,三维瞬态电磁场仿真显示短路电流上升率为20 A/μs、二次绕组匝数为30匝时,铁芯二次绕组侧输出电压不小于14 V。最后设计制作了采用无源电磁式电流互感器作为触发装置的混合型限流熔断器工程样机,并进行了短路电流检测实验,实验结果与仿真基本一致,证明了铁芯设计的准确性和有效性。

Device performance limit of monolayer SnSe_(2) MOSFET

Two-dimensional(2D)semiconductors are attractive channels to shrink the scale of field-effect transistors(FETs),and among which the anisotropic one is more advantageous for a higher on-state current(I_(on)).Monolayer(ML)SnSe_(2),as an abundant,economic,nontoxic,and stable two-dimensional material,possesses an anisotropic electronic nature.Herein,we study the device performances of the ML SnSe_(2) metal-oxide-semiconductor FETs(MOSFETs)and deduce their performance limit to an ultrashort gate length(L_(g))and ultralow supply voltage(V_(dd))by using the ab initio quantum transport simulation.An ultrahigh I_(on) of 5,660 and 3,145µA/µm is acquired for the n-type 10-nm-L_(g) ML SnSe_(2) MOSFET at V_(dd)=0.7 V for high-performance(HP)and low-power(LP)applications,respectively.Specifically,until L_(g) scales down to 2 and 3 nm,the MOSFETs(at V_(dd)=0.65 V)surpass I_(on),intrinsic delay time(τ),and power-delay product(PDP)of the International Roadmap for Device and Systems(IRDS,2020 version)for HP and LP devices for the year 2028.Moreover,the 5-nm-L_(g) ML SnSe_(2) MOSFET(at V_(dd)=0.4 V)fulfills the IRDS HP device and the 7-nm-L_(g) MOSFET(at V_(dd)=0.55 V)fulfills the IRDS LP device for the year 2034.

最终接头临时锚拉系统设计及工艺研究

“整体预制水下推出式”最终接头结构设计复杂,安装精度要求高,施工风险大。为有效保证最终接头水下施工过程安全可控,保证最终接头及其两侧已安装沉管施工质量,通过安装特定结构的临时锚拉系统,抵消水力压接过程中GINA止水带反弹作用力。根据其工作原理及受力特点,结合有关资料进一步研究、制定了大应力作用下限位刚拉杆拆除方案,确保最终接头施工顺利实现提供必要基础。通过现场实践,该系统及工艺可在类似工程中参考应用。

某推拉窗窗扇坠落事故的原因分析以及警示

分析了某推拉窗窗扇坠落事故的原因,并简要阐述了事故原因的调查过程。通过案例分析,提出推拉窗规范安装防脱落装置和正确选用限位装置的必要性。

曳引电梯限速器电气安全装置的检验

电梯限速器是电梯系统的关键组成部分,电梯限速器安全开关是电梯安全保护系统中的关键部件,曳引电梯限速器在电气安全方面的重要性日益突显。然而,由于制造差异、工作原理和型号规格等不同,限速器动作的方式也不一致,尤其是电气安全开关的数量位置,不同的限速器也不一样。通过深入分析市面上普遍较为常见的限速器,从安全装置的动作情况和设置情况两个方面论述了电梯限速器安全开关的检验,着重分析了电梯限速器检验过程中容易忽视的安全开关的设置问题。最后提出了限速器开关校验过程中的几点措施,以此降低电梯的安全事故的概率。该校验方法能够有效地发现限速器电气安全开关存在的问题,确保检验的质量,为电梯系统的安全运行提供了可靠的保障。

既有砌体结构摩擦滑移隔震加固工程有限元分析

摩擦滑移隔震技术具有成本经济、设计简洁等优点,广泛应用于各类隔震建筑中。基于摩擦滑移的隔震原理,结合既有砌体结构的特征,设计出新型摩擦滑移装置,并将其应用于既有结构加固设计中。结合工程实例,通过建立3组不同连接方式的多层砌体结构模型,对比基础不同连接形式在罕遇地震下的加速度、基底剪力及位移反应。试验结果表明:摩擦滑移隔震装置的设置能够大大降低结构的地震响应。设置限位型的摩擦滑移连接也能起良好的隔震效果,限位装置的增加能够有效地减小底部滑移量,满足工程使用的要求。根据工程实例,对摩擦滑移隔震的“双基础圈梁”装置的具体构造,以及在加固设计中的平面布置及关键部位的构造等进行说明,为摩擦滑移技术在加固设计中的应用与进一步优化提供思路。

一种立式机架升降装置控制方法的应用

介绍了一种新型的立式机架升降装置控制方法和应用。通过利用限制变频装置转矩输出特性,结合立式机架升降实际状态,PLC控制系统按照预先设定的升降转矩值控制升降操作。在进行立式机架升降操作时,把变频装置的输出转矩控制在预先设定的允许范围内,确保升降机构不会由于卡阻或者超行程等现场不稳定状态,导致过负荷带来设备损坏,从而预防升降装置损坏引起的重大设备事故。方法应用于现场后,避免了恶劣环境下现场检测元器件状态失效对立式机架升降操作的不利影响,解决了立式机架升降装置频繁损坏问题,杜绝了由于立式机架升降操作导致的升降装置故障。