A General Strategy for Ordered Carrier Transport of Quasi‑2D and 3D Perovskite Films for Giant Self‑Powered Photoresponse and Ultrahigh Stability

Organic–inorganic hybrid perovskite materials have been focusing more attention in the field of self-powered photodetectors due to their superb photoelectric properties.However,a universal growth approach is required and challenging to realize vertically oriented growth and grain boundary fusion of 2D and 3D perovskite grains to promote ordered carrier transport,which determines superior photoresponse and high stability.Herein,a general thermal-pressed(TP)strategy is designed to solve the above issues,achieving uniaxial orientation and single-grain penetration along the film thickness direction.It constructs the efficient channel for ordered carrier transport between two electrodes.Combining of the improved crystal quality and lower trap-state density,the quasi-2D and 3D perovskite-based self-powered photodetector devices(with/without hole transport layer)all exhibit giant and stable photoresponse in a wide spectrum range and specific wavelength laser.For the MAPbI_(3)-based self-powered photodetectors,the largest R_(λ) value is as high as 0.57 A W^(−1)at 760 nm,which is larger than most reported results.Meanwhile,under laser illumination(532 nm),the FPEA_(2)MA_(4)Pb_(5)I_(16)-based device exhibits a high responsivity(0.4 A W^(−1)) value,which is one of the best results in 2DRP self-powered photodetectors.In addition,fast response,ultralow detection limit,and markedly improved humidity,optical and heat stabilities are clearly demonstrated for these TP-based devices.

Progression in the Oxidation Stability of MXenes

MXenes are under the spotlight due to their versatile physicochemical characteristics. Since their discovery in 2011, significant advancements have been achieved in their synthesis and application sectors. However, the spontaneous oxidation of MXenes, which is critical to its processing and product lifespan, has gotten less attention due to its chemical complexity and poorly understood oxidation mechanism. This perspective focuses on the oxidation stability of MXenes and addresses the most recent advancements in understanding and the possible countermeasures to limit the spontaneous oxidation of MXenes. A section is dedicated to the presently accessible methods for monitoring oxidation, with a discussion on the debatable oxidation mechanism and coherently operating factors that contribute to the complexity of MXenes oxidation. The current potential solutions for mitigating MXenes oxidation and the existing challenges are also discussed with prospects to prolong MXene's shelf-life storage and expand their application scope.

Influence of control strategy on stability of dual-spin projectiles with fixed canards

Existing literature has shown that the control force at the nose could cause dynamic instability for controlled projectiles. To lower the adverse impact on the dual-spin projectile with fixed canards under the premise of meeting guidance system requirements, the influence of control moment provided by a motor on the flight stability is analyzed in this paper. Firstly, the effect of the rolling movement on stability is analyzed based on the stability criterion derived using the Hurwitz stability theory. Secondly, the evaluation parameters combining the features of different control periods that could assess the variation of stability features after the motor torque are obtained. These effective formulas are used to indicate that, to reduce the flight instability risks, the stabilized rolling speed of roll speed keeping period should be as small as possible; the variation trend of motor torque during the rolling speed controlling period and the roll angle of the forward body during roll angle switching period are recommended corresponding to the projectile and trajectory characteristics. Moreover,detailed numerical simulations of 155 mm dual-spin projectile are satisfactory agreement with the theoretical results.

MTCR-CR Routing Strategy for Connection-Oriented Routing over Satellite Networks

The high-speed movement of satellites makes it not feasible to directly apply the mature routing scheme on the ground to the satellite network.DT-DVTR in the snapshot-based connectionoriented routing strategy is one of the representative solutions,but it still has room for improvement in terms of routing stability.In this paper,we propose an improved scheme for connection-oriented routing strategy named the Minimal Topology Change Routing based on Collaborative Rules(MTCR-CR).The MTCR-CR uses continuous time static topology snapshots based on satellite status to search for intersatellite link(ISL)construction solutions that meet the minimum number of topology changes to avoid route oscillations.The simulation results in Beidou-3 show that compared with DT-DVTR,MTCR-CR reduces the number of routing changes by about 92%,the number of path changes caused by routing changes is about38%,and the rerouting time is reduced by approximately 47%.At the same time,in order to show our algorithm more comprehensively,the same experimental index test was also carried out on the Globalstar satellite constellation.

An Experimental Investigation on Low Load Combustion Stability and Cold-Firing Capacity of a Gasoline Compression Ignition Engine

Gasoline compression ignition (GCI) is one of the most promising combustion concepts to maintain low pollutant emissions and high efficiency. However, low load combustion stability and firing in cold-start operations are two major challenges for GCI combustion. Strategies including negative valve overlap (NVO), advanced injection strategies, fuel reforming, and intake preheating have been proposed in order to solve these difficulties;however, the cold start is still an obstacle. The objective of this work is to study effective methods to achieve GCI engine cold start-up. This work combines NVO, in-cylinder fuel reforming, and intake preheating to achieve quick firing under cold-start conditions and the subsequent warmup conditions. The results show that start of injection (SOI) during the intake stroke yields the best fuel economy, and injection during the compression stroke has the potential to extend the low load limit. Furthermore, SOI during the NVO period grants the ability to operate under engine conditions with cold intake air and coolant. With highly reactive products made by in-cylinder fuel reforming and fast heat accumulation in the combustion chamber, the NVO injection strategy is highly appropriate for GCI firing. An additional assisted technical method, such as intake preheating, is required to ignite the first firing cycle for a cold-start process. With the combination of NVO, in-cylinder fuel reforming, and intake preheating, the GCI engine successfully started within five combustion cycles in the experiment. After the firing process, the engine could stably operate without further intake preheating;thus, this method is appropriate for engine cold-start and warm-up.

Metal-organic frameworks with mixed-ligands strategy as heterogeneous nucleation center to assist crystallization for efficient and stable perovskite solar cells

Deep-level defects and random oriented configuration in perovskite crystallization process would cause the nonradiative recombination and further affect the performance of perovskite solar cells(PSCs).Herein,two metal-organic frameworks(MOFs)with tunable Lewis-base passivation sites have been constructed(Cd-Httb and Cd-Httb-BDC,Httb=5-(4-(1H-1,2,4-triazole-1-yl)benzyl)-1h-tetrazole,BDC=1,4-dicarboxybenzene)to eliminate deep-level defects and simultaneously as nanostructured heterogeneous nucleation seed to assist the growth of large-grained perovskite films.Compared with the control and Cd-Httb,Cd-Httb-BDC designed with mix-ligands strategy exhibited the enhanced inducted effect on the crystallization and nucleation of high-quality perovskite films during annealing process.Consequently,the resultant Cd-Httb-BDC-modified device achieved higher power conversion efficiency(PCE)(22.18%)than the control(20.89%)and Cd-Httb(21.56%).Meanwhile,the unencapsulated Cd-Httb-BDC-modified device still maintained 90%of initial PCE after 1500 h in ambient conditions and exhibited enhanced thermal stability(85℃ in N_(2) atmosphere).This work presented a successful example of mixligands strategy on construction of high-quality MOF-assisted perovskite films for high-efficient and stable PSCs.

Lithium nitrate regulated carbonate electrolytes for practical Li-metal batteries: Mechanisms, principles and strategies

Li-metal batteries(LMBs)regain research prominence owing to the ever-increasing high-energy requirements.Commercially available carbonate electrolytes exhibit unfavourable parasitic reactions with Limetal anode(LMA),leading to the formation of unstable solid electrolyte interphase(SEI)and the breed of Li dendrites/dead Li.Significantly,lithium nitrate(LiNO_(3)),an excellent film-forming additive,proves crucial to construct a robust Li_(3)N/Li_(2)O/Li_(x)NO_(y)-rich SEI after combining with ether-based electrolytes.Thus,the given challenge leads to natural ideas which suggest the incorporation of LiNO_(3) into commercial carbonate for practical LMBs.Regrettably,LiNO_(3) demonstrates limited solubility(~800 ppm)in commercial carbonate electrolytes.Thence,developing stable SEI and dendrite-free LMA with the incorporation of LiNO_(3) into carbonate electrolytes is an efficacious strategy to realize robust LMBs via a scalable and cost-effective route.Therefore,this review unravels the grievances between LMA,LiNO_(3)and carbonate electrolytes,and enables a comprehensive analysis of LMA stabilizing mechanism with LiNO_(3),dissolution principle of LiNO_(3) in carbonate electrolytes,and LiNO_(3) introduction strategies.This review converges attention on a point that the LiNO_(3)-introduction into commercial carbonate electrolytes is an imperious choice to realize practical LMBs with commercial 4 V layered cathode.

Stabilization strategy of a car-following model with multiple time delays of the drivers

An extended car-following model with multiple delays is constructed to describe driver's driving behavior.Through stability analysis,the stability condition of this uncontrolled model is given.To dampen the negative impact of the driver's multiple delays(i.e.,stability condition is not satisfied),a novel control strategy is proposed to assist the driver in adjusting vehicle operation.The control strategy consists of two parts:the design of control term as well as the design of the parameters in the term.Bifurcation analysis is performed to illustrate the necessity of the design of parameters in control terms.In the course of the design of parameters in the control term,we improve the definite integral stability method to reduce the iterations by incorporating the characteristics of bifurcation,which can determine the appropriate parameters in the control terms more quickly.Finally,in the case study,we validate the control strategy by utilizing measured data and configuring scenario,which is closer to the actual traffic.The results of validation show that the control strategy can effectively stabilize the unstable traffic flow caused by driver's delays.

Transient Stability Analysis of Hu-Liao HVDC and AC Parallel Transmission System

In this paper, transient stability analysis was focused on Hu-Liao HVDC and AC parallel transmission system. The Hu-Liao HVDC project was introduced;Simulation method and mathematic models of AC and DC systems were stu-died as well as corresponding regulators and controllers. The dynamic performance and the interaction between AC and DC systems during serious disturbance were researched by detail time-domain simulation. Comparison was also made under different operation schemes. The research will bring important and significant reference for further operation and stability control of Hu-Liao HVDC and AC system.

平抑风电波动的电-氢混合储能容量优化配置

针对电-氢混合系统协同平抑接入新型电力系统的新能源波动问题,提出考虑碱性电解槽运行特性的电-氢混合储能容量优化配置方案。首先,基于经验模态分解,将原始风电功率信号分解为符合波动量限值的直接并网分量和混合储能功率任务;在综合考虑电化学储能和氢储能介质充放电功率约束和存储状态约束的基础上,制定计及碱性电解槽运行特性的混合储能能量管理策略。基于此策略,以综合成本最小为目标,建立用于平抑风电波动的电-氢混合储能容量配置模型,并通过实际数据进行计算分析。算例结果表明,所提策略下的容量配置方案,在满足平抑需求的前提下,可以有效提高系统经济性。

Effect of the Policies to Prevent Drug Shortage and Stabilize Drug Prices in Medical Institutions

Objective To evaluate the effect of some policies to prevent drug shortage and stabilize drug prices,and to provide reference for improving relevant policies.Methods With a combination of random stratified sampling and quota sampling,532 medical institutions in 20 provinces were selected to carry out questionnaire surveys.Then,a comparative analysis was made to study the changes of drugs on the shortage list and drugs on non-shortage list before and after the release of the policy of ensuring supply and stabilizing prices.Results and Conclusion The policy played an important role in curbing the growth of drug shortage in the medical institutions,but it did not curb the growth of drugs on non-shortage list.Besides,the drugs on non-shortage list showed an overall fluctuation and upward trend.Meanwhile,from the perspective of drug prices,the price stability problem of drugs on the shortage list and on the non-shortage list became more serious,and the average price increase was 256% and 239%,respectively.The implementation of policies related to the supply and price stability of drugs prevents the growth trend of drug shortages in the list of medical institutions,which has been recognized by most medical institutions.However,there is an increasing trend in the number of drugs on non-shortage list.In addition,the price increase of drugs on both the shortage list and non-shortage list is severe.Some medical institutions report that they have difficulties in using the information reporting system of drug shortage and the classification,grading and the alternative use of drug shortages.It is recommended to strengthen the management of price stabilization of drugs on the shortage list.Further attention should be paid to the supply and price stabilization of drugs on non-shortage list.At the same time,trainings in the classification and substitution of drug shortage and information reporting system should be actively organized,thus comprehensively improving the capabilities of medical institutions at all levels to deal with the problem of drug shortage.

“双循环”格局下中国饲料粮进口稳定性研究

“双循环”格局下适度进口已成为缓解国内饲料粮供需矛盾的现实选择。在有效利用国际饲料粮市场的同时,降低饲料粮进口的稳定性风险,既重要且必要。在对国内饲料粮供需形势精准判断的基础上,综合分析饲料粮进口的可获性与可供性,并采用香农熵指数法对饲料粮的进口来源稳定性进行评估。结果表明:国内饲料粮供需格局趋紧并呈现常态化发展趋势,供需缺口不断扩大,适度进口饲料粮是大势所需。总量上,世界饲料粮的供应潜力巨大;时点上,我国与国际饲料粮生产波动的相关性较弱。因此,利用国际市场弥补国内饲料粮的供需缺口是可行的。1992—2020年,我国饲料粮进口的稳定程度整体处于较低水平,其中,玉米、麦麸和大麦的变动幅度较大,大豆的波动幅度较小。在新一轮高水平开放格局下,亟须完善政策体系、优化进口结构、提高进口稳定性,构建“双循环”新发展格局下开放型的国家饲料粮安全保障体系。

两种新型稳控系统的对比研究

为适应新型电力系统环境下电网安全稳定性的快速大幅变化,需要研制新型安全稳定的控制系统。新型稳控系统存在两种技术方案:智能决策自升级稳控系统和在线稳控系统。从构建思路、系统架构、关键技术和实现难度等方面对这两种方案进行了研究,阐述了两者之间的区别与联系,并给出了推荐方案,为稳控系统的技术发展提供了有益思路。

拿什么留住边民:基于云南3个边境县的混合研究

边民居留稳定性对于保障边境安全、稳定和繁荣具有重要现实意义。文章从新劳动力迁移理论出发,基于个人因素和家庭因素两个维度选取6个条件变量,对云南省三个边境县展开问卷调查,运用fsQCA、logistic、边民访谈和地区个案进行混合方法的三角互证,探究边民居留稳定性影响因素与组态效应。研究发现:边民迁移动力为生存发展型,阻力源自家庭照护与知能不足,迁移地点倾向省外。组态分析得出边民高居留稳定性的组态包括“长者稳健”“婚姻民族黏性”“低知女性驻留”。logistic回归分析复证年龄、民族、婚姻状况对边民居留稳定性的作用显著。其政策寓意在于:“产业强边”应侧重民族文化产业;“社保稳边”应强化普惠适老型和家庭亲厚型社保;“教育兴边”需关注女性受教育权和发展权;“移民实边”目标可聚焦“新边民”的居留韧性。文章据此构建“产业—社保—教育”复合助推策略,以“产业强边”为主体,以“社保稳边”与“教育兴边”为两翼,介绍各地典型做法与经验,提供方法菜单,以助推边民居留。

区域新能源并网暂态功角稳定分析与紧急控制策略优化

随着新型电力系统发展和新能源机组不断投产,南方区域将形成多区域新能源与邻近常规电源联合集中接入系统的场景。新能源集中接入常与常规电源共用输电通道,将影响区域系统暂态稳定特性及输送通道的传输能力,使南方区域系统的安全稳定运行和风险防控面临了前所未有的挑战。为深入研究区域新能源送出的稳定特性建立了区域新能源交流集中送出的等值系统模型,分析了新能源并入对区域系统对暂态稳定特性影响的主要机理。基于等面积法则对区域送出系统暂态过程的加、减速面积进行了定量分析,提出了紧急控制切机策略的协调优化方法,实现区域送出传统机组与新能源机组紧急控制切机量及控制代价的最小化的切机策略配置。最终,基于广东区域海风火电打捆送出系统为例,对分析结果的正确性进行了验证。

好氧颗粒污泥结构稳定强化策略研究评述

好氧颗粒污泥由于其强大的抗冲击能力和出色的除污效果,在常规活性污泥性能升级改造中得到热点关注,而其形成时间较长和稳定性较弱的问题限制了在污水处理厂的商业化应用。为了能尽快将好氧颗粒污泥技术广泛投入到污水处理领域中,有必要重新深入认知形成机制和结构稳定性的关键影响因素,从而达到精准调控其形成过程和实现长期稳定有效使用目的。该文通过系统地收集和分析相关研究文献,梳理了好氧颗粒污泥形成机制,形成机制主要集中在七大类假说,即晶核理论、自凝聚原理、胞外聚合物假说、丝状菌假说、细胞疏水性假说、选择压驱动假说和阶段假说等。从宏观和微观两个角度分析了其稳定性的关键影响因素。宏观上,反应器的高径比、水力剪切力、有机负荷率等因素都会对好氧颗粒污泥的形成和稳定性产生影响;微观上,微生物的群体感应及其分泌的胞外聚合物等因素也发挥着重要作用。详细阐述了好氧颗粒污泥微生物群落组成和功能,进一步整理了好氧颗粒污泥微生物群落与颗粒结构稳定性能的内在关联。依据以上研究进展并结合工程应用的实际情况和需求,总结概况了好氧颗粒污泥结构稳定强化策略,即控制污泥粒径、改善进料与曝气方式、调控胞外聚合物分泌、调控群体感应等。初步构想了基于生物强化、崩解和再造粒的技术路径,具有生化、物化和化学理论融合的特点,在一定程度上可能代表了群体感应-晶核凝聚共诱导造粒的研究方向。

稳控装置在海油平台电网的应用

稳控装置采用先进的平台化设计思想,通过硬件、软件模块化设计提供标准模型服务。稳控装置是陆地电网遇到大扰动时,为保证电力系统稳定性而在电厂或变电站内装设的控制设备,按标准化策略实现切机、切负荷、快速减出力等功能。本文通过对国产电网稳控装置标准服务的研究,制定适应于海洋平台电站管理的稳控策略,完成稳控装置智能化策略和功能研发;根据现场策略需求配置稳控主从机,研发适用于现场工况的控制处置策略和智能化需求。

基于演化博弈的民航危险品运输培训监管

为促进民航危险品运输培训精准监管,提升民航监管效能,实现合规培训与监管的最佳局面,进一步保障航空运输安全。首先从行为交互和微观经济学的角度,运用演化博弈方法,构建危险品运输培训机构和民航局双方演化博弈模型,定量分析博弈双方行为策略选择的情境条件及形成原因;然后运用MATLAB软件对重要参数的敏感性进行数值仿真分析,探讨受训者能力不足造成不安全事件概率、查处成功率、处罚力度和监管成本4个重要参数对系统演化路径及结果的影响效应;最后从管理层面对民航危险品运输培训监管提出有针对性的建议及措施。结果表明:受训者能力不足造成不安全事件概率、查处成功率和处罚力度3个参数对博弈双方行为选择具有正效应,而监管成本对博弈双方行为选择具有负效应。

基于模糊理论的输电网络电压无功控制策略

为解决新能源、电动汽车、储能等新技术应用下,高复杂度电力系统电压稳定控制问题,提出了一种基于模糊理论的输电网络电压无功控制策略。该方法引入模糊理论中的隶属度函数,根据系统节点与不同分区之间的耦合程度制定无功控制策略。根据灵敏度计算网络各个节点之间的电气距离,通过模糊聚类算法对节点进行初步分区,并采用聚类融合算法对聚类产生的多个结果进行融合,从而得到最终分区结果。根据关键节点对各个分区的隶属度制定主辅控制策略。IEEE30节点输电网络的算例分析表明,该控制策略可以有效实现对无功功率的控制。

演化博弈视角下高校学报联合办刊策略

引入协同增效收益及其分配系数、成本、投机收益、惩罚等影响因素,构建高校学报联合办刊演化博弈模型,求得演化均衡解。结果表明:协同增效收益、惩罚对演化博弈系统最佳稳定状态具有正向影响;成本、投机收益对演化博弈系统最佳稳定状态具有负向影响;存在合理的协同增效收益分配系数。联合办刊需要重视各高校学报办刊资源的异质性和互补性,加强顶层设计明晰各高校学报权、责、利,重视并有效减少联合办刊运营成本。