Dimensionality regulation in tin halide perovskite solar cells: Toward high performance and stability

Tin halide perovskites(THPs)have received extensive attention due to their low toxicity and excellent optoelectronic properties,and are considered to be the most promising alternatives to develop efficient lead-free perovskite solar cells.However,due to the unique and inherent characteristics of Sn^(2+)being easily oxidized to Sn^(4+)and fast crystallization,tin perovskite solar cells(TPSCs)show relatively poor performance and stability,compared to the lead counterparts.Recently,the introduction of bulky organic spacers into three-dimensional(3D)THPs for dimensional regulation can not only prevent the intrusion of water and oxygen,but also inhibit the self-doping effect and ion migration.In this review,we will detail how dimensional regulation enables TPSCs with high performance and superior stability.First,we summarize the intrinsic properties of THPs and analyze the root causes of their poor performance and instability.Next,we discuss the specific structure and types of the dimensional regulation strategy.Then,the mechanism of dimensional regulation is discussed in detail,mainly from inhibiting the Sn^(2+)oxidation,optimizing crystallization,passivating defects,and improving energy level alignment.Finally,future challenges and prospects for dimensional regulation are elaborated to help researchers develop more efficient and stable TPSCs.

Model test and numerical simulation on the dynamic stability of the bedding rock slope under frequent microseisms

Shake table testing was performed to investigate the dynamic stability of a mid-dip bedding rock slope under frequent earthquakes. Then, numerical modelling was established to further study the slope dynamic stability under purely microseisms and the influence of five factors, including seismic amplitude, slope height, slope angle, strata inclination and strata thickness, were considered. The experimental results show that the natural frequency of the slope decreases and damping ratio increases as the earthquake loading times increase. The dynamic strength reduction method is adopted for the stability evaluation of the bedding rock slope in numerical simulation, and the slope stability decreases with the increase of seismic amplitude, increase of slope height, reduction of strata thickness and increase of slope angle. The failure mode of a mid-dip bedding rock slope in the shaking table test is integral slipping along the bedding surface with dipping tensile cracks at the slope rear edge going through the bedding surfaces. In the numerical simulation, the long-term stability of a mid-dip bedding slope is worst under frequent microseisms and the slope is at risk of integral sliding instability, whereas the slope rock mass is more broken than shown in the shaking table test. The research results are of practical significance to better understand the formation mechanism of reservoir landslides and prevent future landslide disasters.

Full-scale multi-functional test platform for investigating mechanical performance of track–subgrade systems of high-speed railways

Motivated by the huge practical engineering demand for the fundamental understanding of mechanical characteristics of high-speed railway infrastructure,a fullscale multi-functional test platform for high-speed railway track–subgrade system is developed in this paper,and its main functions for investigating the mechanical performance of track–subgrade systems are elaborated with three typical experimental examples.Comprising the full-scale subgrade structure and all the five types of track structures adopted in Chinese high-speed railways,namely the CRTS I,the CRTS II and the CRTS III ballastless tracks,the double-block ballastless track and the ballasted track,the test platform is established strictly according to the construction standard of Chinese high-speed railways.Three kinds of effective loading methods are employed,including the real bogie loading,multi-point loading and the impact loading.Various types of sensors are adopted in different components of the five types of track–subgrade systems to measure the displacement,acceleration,pressure,structural strain and deformation,etc.Utilizing this test platform,both dynamic characteristics and long-term performance evolution of high-speed railway track–subgrade systems can be investigated,being able to satisfy the actual demand for large-scale operation of Chinese high-speed railways.As examples,three typical experimental studies are presented to elucidate the comprehensive functionalities of the full-scale multi-functional test platform for exploring the dynamic performance and its long-term evolution of ballastless track systems and for studying the long-term accumulative settlement of the ballasted track–subgrade system in high-speed railways.Some interesting phenomena and meaningful results are captured by the developed test platform,which provide a useful guidance for the scientific operation and maintenance of high-speed railway infrastructure.

Stability Test of Naomai Xingshen Capsules

[Objectives]To explore the stability of Naomai Xingshen Capsules.[Methods]Accelerated test and long-term test were carried out to investigate the changes in properties,identification,moisture,disintegration time and microbial limit of Naomai Xingshen Capsules.[Results]There were basically no changes in all indicators for the three batches of samples(after 6-month accelerated test and 24-month long-term test),and they all met the requirements of quality standards.[Conclusions]The preparation of Naomai Xingshen Capsules is stable and reliable,and the stability test provides a reliable basis for its expiration date.

Experimental Study on the Stability of Shuji Tablets

[Objectives]To investigate the stability of Shuji tablets.[Methods]Accelerated test and long-term test were used to investigate the changes of tablet properties,weight difference,alcohol-soluble extract,disintegration time and microbial limit.[Results]All the indicators of the three batches of samples(after 6 months of accelerated test and 18 months of long-term test)basically remained unchanged and all met the standards of the quality standard.[Conclusions]The preparation is stable and reliable,and the stability test provides a reliable basis for its validity.

Physical modeling of long-term dynamic characteristics of the subgrade for medium-low-speed maglevs

To investigate the dynamic characteristics and long-term dynamic stability of the new subgrade structure of medium-low-speed(MLS)maglevs,cyclic vibration tests were performed under natural and rainfall conditions,and the dynamic response of the subgrade structure was monitored.The dynamic response attenuation characteristics along the depth direction of the subgrade were compared,and the distribution characteristics of the dynamic stress on the surface of the subgrade along the longitudinal direction of the line were analyzed.The critical dynamic stress and cumulative deformation were used as indicators to evaluate the long-term dynamic stability of the subgrade.Results show that water has a certain effect on the dynamic characteristics of the subgrade,and the dynamic stress and acceleration increase with the water content.With the dowel steel structure set between the rail-bearing beams,stress concentration at the end of the loaded beam can be prevented,and the diffusion distance of the dynamic stress along the longitudinal direction increases.The dynamic stress measured in the subgrade bed range is less than 1/5 of the critical dynamic stress.The postconstruction settlement of the subgrade after similarity ratio conversion is 3.94 mm and 7.72 mm under natural and rainfall conditions,respectively,and both values are less than the 30 mm limit,indicating that the MLS maglev subgrade structure has good long-term dynamic stability.

基于ADAMS/CAR的某SUV汽车操纵稳定性仿真实验分析及优化

操纵稳定性是车辆正常行驶时受到外界扰动后保持稳定运行或迅速恢复稳定的一种能力,对车辆安全平稳运行至关重要。为优化车辆的操纵稳定性,对某SUV汽车进行动力性分析,建立物理模型和数学模型,阐述悬架对汽车操纵稳定性的影响。采用ADAMS/CAR进行整车建模,运用MATLAB软件对操纵稳定性评价指标进行评分。选取悬架的力学特性参数作为优化变量,以操纵稳定性评价指标的评分作为优化目标,通过对比选取最优方案。研究结果表明:NGSA-II算法对道路实验评价指标的优化效果较好,能够显著提升整车的操纵稳定性。

Performances and long-term stability of the LHAASO-KM2A prototype array

A prototype array for the LHAASO-KM2A, which consists of 42 detector units and fully overlaps the ARGO-YBJ experiment, was set up at the Yangbajing cosmic ray observatory and has been in stable operation since Octoter 2010. The resulting performances of the KM2A electromagnetic particle detector prototypes fully meet the design requirements. Through hybrid observation of cosmic ray showers with the ARGO-YBJ experiment, the performances and long-term stability of the prototype array are tested and the results are consistent with expectation. The cosmic ray moon shadow observed by the prototype array is also presented.

成形网对液压过滤材料性能稳定性的影响

液压过滤材料在过滤过程中会出现过滤比严重下降的问题,极大影响了滤材过滤性能的稳定性。首先利用Geodict软件模拟了滤材孔径分布不均匀对过滤性能的影响,结果表明,在平均孔径一定的情况下,滤材的最大孔径越大,滤材过滤性能的稳定性越差;然后采用实验探究了成形网目数对滤材孔径分布以及液体过滤性能的影响,结果表明,当成形网的目数大于等于400目时,不同直径、不同定量的滤材在成形过程中的流失率和孔径分布逐渐趋于稳定,在滤材的物理参数和过滤精度接近时,500目成形网制备的滤材过滤性能的稳定性要高于80目成形网制备的滤材。

正交试验综合评分法用于预拌泡沫混凝土配合比优化设计技术研究

通过正交试验,针对胶凝材料组成、矿物掺合料、水胶比、发泡剂等因素,对泡沫混凝土的发泡效果、湿表观密度、凝结时间、抗压强度等性能的影响程度和规律进行了研究分析,采用综合评分法确定最优配合比,结果表明水胶比定则并不适用于泡沫混凝土;通过掺加和调整减水剂、稳泡剂和保水剂、促凝剂对泡沫混凝土的流动性、稳泡性能及凝结性能进行改进;通过加压试验方法测定泡沫混凝土的压力变化量,为配合比设计优化提供评价依据。

欧洲地铁、城轨及高端铁路货车标记自粘膜性能的检测方法研究

文章对出口欧洲的地铁、城轨及高端铁路货车车体外表面标识及内部装饰应用的自粘膜性能进行了深入研究,从功能、基础材料、通用参数等几个方面详细介绍了自粘膜的特点,并对该类型产品的检测方法及性能试验进行了归纳总结,其中包括对自粘膜厚度、光泽度、粘合性、尺寸稳定性的一般检测,较为复杂的化学稳定性检测以及应用氙辐射方法的耐候性检测。研究了化学稳定性检测中耐清洗剂特性的要求以及对油漆清除剂的抗性的要求。此外,重点分析了耐候性检测中氙辐射的检测方法、实验室或实验箱条件及评定依据以及辐射度、光照、喷淋、滤镜等参数对应的欧洲标准和行业一致性的规定。为出口欧洲铁路货车的相关设计、工艺、质检人员及自粘膜配件相关供应商提供检测方法的参考。

长江细砂路用性能分析及路基断面设计与施工技术研究

随着生态环境和基本农田保护意识的逐渐增强,长江沿岸道路建设的填筑材料越来越多地采用了长江细砂,因地制宜地利用了当地料源。文章通过填砂路基断面结构形式的设计、路基稳定性计算验证及原材料性能检测分析,结果表明填砂路基的梯形包边结构稳定可靠,长江细砂亦是良好的路基填筑材料。结合工程实例的应用,试验总结了路基填砂施工中的机械组合、工序流程及工艺参数,经大面积填筑施工后的压实度检测和沉降观测,效果良好,可为后续同类型施工提供一定的借鉴意义。

炸药抗过载性能试验方法

炸药抗过载性能的测试与表征,是侵彻战斗部装药选型的重要依据。基于单自由度受迫振动模型,建立炸药抗过载性能试验测试装置,模拟战斗部侵彻过程中炸药装药所承受的力学环境和变形行为,提出过载条件下炸药的点火判据∫σdσ(σ和σ分别为应力和应力率),形成了炸药抗过载性能表征方法。采用该装置对3种典型的DNAN基不敏感侵彻熔注炸药的抗过载性能进行测试,得到它们的点火阈值分别为1.8 GPa^(2)/ms、2.2 GPa^(2)/ms和3.3 GPa^(2)/ms;采用平头弹侵彻试验方法,对上述3种炸药的抗过载性能进行验证,得到了3种炸药的着靶爆炸反应的临界速度范围分别为444~475 m/s、512~531 m/s和大于570 m/s。研究结果表明,炸药抗过载性能测试和平头弹侵彻试验方法试验的验证结果一致,说明炸药抗过载性能试验方法可作为侵彻战斗部装药选型的科学有效手段。

高效液相色谱法测定皮革中7种苯并三唑类防紫外线稳定剂

建立了高效液相色谱法测定皮革产品中7种苯并三唑类防紫外线稳定剂迁移量的方法。该方法采以甲醇作为提取溶剂,通过超声萃取,采用外标法进行定量,试验结果表明:7种目标物能够被有效分离,目标物浓度在0.1~30.0 mg/L范围内与峰面积呈良好的线性关系,线性相关系数均在0.99907以上,检出限在0.33~0.99 mg/kg。方法的平均回收率为85.98%~94.13%,相对标准偏差为2.58%~4.05%。该方法准确可靠,适用于皮革产品中苯并三唑类防紫外线稳定剂的检测分析。

海浪扰动下电液3-UPS/S舰船并联稳定平台振动特性分析

针对电液驱动的舰船并联稳定平台在实际工况下的振动问题,以电液3-UPS/S舰船并联稳定平台为研究对象,在考虑铰链刚度的基础上应用虚功原理建立稳定平台的动力学模型;通过海浪谱函数,计算了随机海浪激励下船舶的运动响应,进而得到稳定平台跟踪舰船运动的响应规律;分析了稳定平台在随机海浪激励条件下和初始工作空间内的固有频率变化特性;最后,为验证动力学模型的正确性,采用脉冲激励法对稳定平台样机进行模态试验,固有频率理论值与试验值的最大误差为4.66%,可以验证动力学模型的正确性。

稳定杆连杆总成的自动装配工艺与性能检测

针对汽车稳定杆连杆总成的自动装配问题,围绕连杆总成的装配要求,以连杆中心距在120~350 mm范围内的塑料球座类球头总成产品为主要装配对象,优化稳定杆连杆总成自动装配工艺,设计多工位回转工作台及可调式工装夹具,并利用特殊辅具解决卡环安装中容易发生变形的问题。自动装配工艺优化后,提高了生产效率。对某车型稳定杆连杆总成进行装配,通过试验机进行性能检测,验证各项性能均满足技术要求,产品质量稳定,可靠性高。

断级配水泥稳定碎石基层设计

文中分析了形成干涉的级配粒径范围,并以最小振实矿料间隙率VCA和最大CBR值为优化指标,获得了骨架结构粗集料级配组成。根据胶砂填充设计思想对细集料级配及水泥胶凝材料组成进行体积法设计,试验结果表明,与普通水泥稳定级配碎石基层相比,设计的断级配水泥稳定碎石基层抗压强度和弯拉强度均有提升。

半柔性路面磷酸铵镁水泥灌浆料路用性能研究

半柔性路面是一种在大空隙沥青混合料(15%~30%)中灌注水泥基材料而形成的一种刚柔并济的路面形式。为了探究磷酸铵镁水泥作为灌浆材料制备的半柔性路面的路用性能,对不同空隙率的大空隙沥青混合料中灌注磷酸铵镁水泥灌浆材料,制备了不同空隙率的半柔性试件,并对其进行了水稳定性、低温抗裂性能以及高温抗车辙性能测试。试验结果表明:随着沥青混合料空隙率的增大,半柔性试件水稳定性及高温抗车辙性能提高,低温性能下降。

膨润土掺量对沥青性能影响试验分析

为研究膨润土掺量对沥青性能的影响,选用70#基质沥青,按照6种膨润土掺量(即0%、10%、15%、20%、25%、30%)制备试件,并对试件进行马歇尔稳定度试验、间接拉伸强度试验、回弹模量试验及四点弯曲疲劳试验。结果表明,膨润土掺量为20%时,沥青混合料的性能有了明显提高,不仅间接拉伸强度及回弹模量有明显提升,抗变形能力也明显增强。

煤粉工业锅炉低脉动圆盘供料器的研发

为了提高煤粉工业锅炉供料的稳定性,研发了低脉动圆盘供料器,设计了圆盘供料器性能测试系统,并测量了圆盘供料器在6个典型工况下的性能。将圆盘供料器应用在煤粉工业锅炉系统中,验证了圆盘供料器的使用效果。结果表明:圆盘供料器的最大供料量约为2.8 t/h,供料量波动小于±2%。在煤粉工业锅炉系统中应用时,测量到圆盘供料器的最大供料量约为2.56 t/h,锅炉的炉膛负压和烟气氧含量平均波动幅度都下降50%以上。性能测试试验和工业化示范应用结果表明,圆盘供料器达到设计要求,能够实现低脉动供料。