Enhancing performance of low-temperature processed CsPbI2Br all-inorganic perovskite solar cells using polyethylene oxide-modified TiO_(2)

CsPbX_(3)-based(X=I,Br,Cl)inorganic perovskite solar cells(PSCs)prepared by low-temperature process have attracted much attention because of their low cost and excellent thermal stability.However,the high trap state density and serious charge recombination between low-temperature processed TiO_(2)film and inorganic perovskite layer interface seriously restrict the performance of all-inorganic PSCs.Here a thin polyethylene oxide(PEO)layer is employed to modify TiO_(2)film to passivate traps and promote carrier collection.The impacts of PEO layer on microstructure and photoelectric characteristics of TiO_(2)film and related devices are systematically studied.Characterization results suggest that PEO modification can reduce the surface roughness of TiO_(2)film,decrease its average surface potential,and passivate trap states.At optimal conditions,the champion efficiency of CsPbI_(2)Br PSCs with PEO-modified TiO_(2)(PEO-PSCs)has been improved to 11.24%from 9.03%of reference PSCs.Moreover,the hysteresis behavior and charge recombination have been suppressed in PEO-PSCs.

Diagnosis of the Kinetic Energy of the“21·7”Extreme Torrential Rainfall Event in Henan Province,China

An extreme torrential rain(ETR)event occurred in Henan Province,China,during 18-21 July 2021.Based on hourly rain-gauge observations and ERA5 reanalysis data,the ETR was studied from the perspective of kinetic energy(K),which can be divided into rotational wind(V_(R))kinetic energy(K_(R)),divergent wind kinetic energy(K_(D)),and the kinetic energy of the interaction between the divergent and rotational winds(K_(RD)).According to the hourly precipitation intensity variability,the ETR process was divided into an initial stage,a rapid increase stage,and maintenance stage.Results showed that the intensification and maintenance of ETR were closely related to the upper-level K,and most closely related to the upperlevel K_(R),with a correlation coefficient of up to 0.9.In particular,the peak value of hourly rainfall intensity lagged behind the K_(R) by 8 h.Furthermore,diagnosis showed that K transformation from unresolvable to resolvable scales made the ETR increase slowly.The meridional rotational wind(u_(R))and meridional gradient of the geopotential(φ)jointly determined the conversion of available potential energy(APE)to K_(R) through the barotropic process,which dominated the rapid enhancement of K_(R) and then caused the rapid increase in ETR.The transportation of K by rotational wind consumed K_(R),and basically offset the K_(R) produced by the barotropic process,which basically kept K_(R) stable at a high value,thus maintaining the ETR.

Enhanced Extreme Ultraviolet Free Induction Decay Emission Assisted by Attosecond Pulses

We demonstrate the extreme ultraviolet free induction decay emission that can be significantly enhanced by employing isolated attosecond pulses.The near infrared pulses are applied to excite the neon atoms into Rydberg states coherently,and isolated attosecond pulses are used to manipulate populations of the Rydberg states and the subsequent free induction decay process.The time resolved experimental measurement of dependence of the resonance emission yield would help to understand the buildup dynamics of population of excited states.The enhancement assisted by attosecond pulses can serve as a mechanism to develop high-flux extreme ultraviolet light sources.

A Two-step Design Method for Shaft Work Targeting on Low-temperature Process

In low-temperature processes, there are interactions between heat exchanger network(HEN) and refrigeration system. The modification on HEN of the chilling train for increasing energy recovery does not always coordinate with the minimum shaft work consumption of the corresponding refrigeration system. In this paper, a systematic approach for optimizing low-temperature system is presented through mathematical method and exergy analysis. The possibility of "pockets", which appears as right nose section in the grand composite curve(EGCC) of the process, is first optimized. The EGCC with the pockets cutting down is designed as a separate part. A case study is used to illustrate the application of the approach for a HEN of a chilling train with propylene and ethylene refrigerant system in an ethylene production process.

Data processing and initial results from the CE-3 Extreme Ultraviolet Camera

The Extreme Ultraviolet Camera （EUVC） onboard the Chang＇e-3 （CE-3） lander is used to observe the structure and dynamics of Earth＇s plasmasphere from the Moon. By detecting the resonance line emission of helium ions （He＋） at 30.4 nm, the EUVC images the entire plasmasphere with a time resolution of 10 min and a spatial resolution of about 0.1 Earth radius （RE） in a single frame. We first present details about the data processing from EUVC and the data acquisition in the commissioning phase, and then report some initial results, which reflect the basic features of the plas- masphere well. The photon count and emission intensity of EUVC are consistent with previous observations and models, which indicate that the EUVC works normally and can provide high quality data for future studies.

Fast and Balanced Charge Transport Enabled by Solution-Processed Metal Oxide Layers for Efficient and Stable Inverted Perovskite Solar Cells

Metal oxide charge transport materials are preferable for realizing long-term stable and potentially low-cost perovskite solar cells(PSCs).However,due to some technical difficulties(e.g.,intricate fabrication protocols,high-temperature heating process,incompatible solvents,etc.),it is still challenging to achieve efficient and reliable all-metal-oxide-based devices.Here,we developed efficient inverted PSCs(IPSCs)based on solution-processed nickel oxide(NiO_(x))and tin oxide(SnO_(2))nanoparticles,working as hole and electron transport materials respectively,enabling a fast and balanced charge transfer for photogenerated charge carriers.Through further understanding and optimizing the perovskite/metal oxide interfaces,we have realized an outstanding power conversion efficiency(PCE)of 23.5%(the bandgap of the perovskite is 1.62 eV),which is the highest efficiency among IPSCs based on all-metal-oxide charge transport materials.Thanks to these stable metal oxides and improved interface properties,ambient stability(retaining 95%of initial PCE after 1 month),thermal stability(retaining 80%of initial PCE after 2 weeks)and light stability(retaining 90%of initial PCE after 1000 hours aging)of resultant devices are enhanced significantly.In addition,owing to the low-temperature fabrication procedures of the entire device,we have obtained a PCE of over 21%for flexible IPSCs with enhanced operational stability.

New Process of Low-temperature Fixed-bed Fisher-Tropsch Reaction Using JL-GX Catalyst

On April 17, 2017 the new process of low-temperature fixed-bed Fisher-Tropsch reaction using the JL-GX catalyst developed independently by the Beijing Jingli Clean Energy Technology Company, Ltd., has been realized through the commissioning of the commercial demonstration unit at the Xingtai Rising Sun Chemical Company. In comparison with the conventional Fisher-Tropsch process, this novel Fisher-Tropsch process can be adapted to a variety of feed gases, which besides natural gas can also use the industrial offgases (including the coke oven gas, the coal seam gas, the oilfield associated gas, and the marsh gas) to manufacture synthetic chemicals through Fisher-Tropsch process.

A comparative study of CuO/TiO_2-SnO_2,CuO/TiO_2 and CuO/SnO_2 catalysts for low-temperature CO oxidation

Nanometer SnO2 particles were synthesized by sol-gel dialytic processes and used as a support to prepare CuO supported catalysts via a deposition-precipitation method. The samples were characterized by means of TG-DTA, XRD, H2-TPR and XPS. The catalytic activity of the CuO/TiO2-SnO2 catalysts was markedly depended on the loading of CuO, and the optimum CuO loading was 8 wt.% （Tloo = 80 ℃）. The CuO/TiO2-SnO2 catalysts exhibited much higher catalytic activity than the CuO/TiO2 and CuO/SnO2 catalysts. H2-TPR result indicated that a large amount of CuO formed the active site for CO oxidation in 8 wt.% CuO/TiO2-SnO2 catalyst.

Construction of a macromolecular structural model of Chinese lignite and analysis of its low-temperature oxidation behavior

The aim of this paper is to analyze the change in the active structure of lignite during the process of lowtemperature oxidation by constructing a molecular structure model for lignite. Using quantum computation combined with experimental results of proximate analysis, ultimate analysis, Fourier transform infrared spectroscopy(FTIR) and X-ray photoelectron spectroscopy(XPS), a structural model for the large molecular structure was constructed. By analyzing the bond lengths in the model molecule, the evolution law for the active structure of lignite was predicted for the process of low-temperature oxidation. In low-temperature oxidation,alkanes and hydroxyls are the primary active structures observed in lignite, though ether may also react. These active functional groups react with oxygen to release heat, thereby speeding up the reaction between coal and oxygen. Finally, the content of various functional groups in the process of lignite low-temperature oxidation was analyzed by infrared analysis, and the accuracy of the model was verified.

Estimation of extreme wind speed in SCS and NWP by a non-stationary model

In offshore engineering design, it is considerably significant to have an adequately accurate estimation of marine environmental parameters, in particular, the extreme wind speed of tropical cyclone （TC） with different return periods to guarantee the safety in projected operating life period. Based on the 71-year （1945-2015） TC data in the Northwest Pacific （NWP） by the Joint Typhoon Warning Center （JTWC） of US, a notable growth of the TC intensity is observed in the context of climate change. The fact implies that the traditional stationary model might be incapable of predicting parameters in the extreme events. Therefore, a non-stationary model is proposed in this study to estimate extreme wind speed in the South China Sea （SCS） and NWP. We find that the extreme wind speeds of different return periods exhibit an evident enhancement trend, for instance, the extreme wind speeds with different return periods by non- stationary model are 4.1%-4.4% higher than stationary ones in SCS. Also, the spatial distribution of extreme wind speed in NWP has been examined with the same methodology by dividing the west sea areas of the NWP 0°-45°N, 105°E-130°E into 45 subareas of 5° × 5°, where oil and gas resources are abundant. Similarly, remarkable spacial in-homogeneity in the extreme wind speed is seen in this area： the extreme wind speed with 50-year return period in the subarea （15°N-20°N, 115°E-120°E） of Zhongsha and Dongsha Islands is 73.8 m/s, while that in the subarea of Yellow Sea （30°N-35°N, 120°E-125°E） is only 47.1 m/s. As a result, the present study demonstrates that non-stationary and in-homogeneous effects should be taken into consideration in the estimation of extreme wind speed.

A systematic approach for synthesizing a low-temperature distillation system

In this paper, by combining a stochastic optimization method with a refrigeration shaft work targeting method,an approach for the synthesis of a heat integrated complex distillation system in a low-temperature process is presented. The synthesis problem is formulated as a mixed-integer nonlinear programming(MINLP) problem,which is solved by simulated annealing algorithm under a random procedure to explore the optimal operating parameters and the distillation sequence structure. The shaft work targeting method is used to evaluate the minimum energy cost of the corresponding separation system during the optimization without any need for a detailed design for the heat exchanger network(HEN) and the refrigeration system(RS). The method presented in the paper can dramatically reduce the scale and complexity of the problem. A case study of ethylene cold-end separation is used to illustrate the application of the approach. Compared with the original industrial scheme, the result is encouraging.

On the Key Dynamical Processes Supporting the 21.7 Zhengzhou Record-breaking Hourly Rainfall in China

An extremely heavy rainfall event occurred in Zhengzhou,China,on 20 July 2021 and produced an hourly rainfall rate of 201.9 mm,which broke the station record for China's Mainland.Based on radar observations and a convection-permitting simulation using the WRF-ARW model,this paper investigates the multiscale processes,especially those at the mesoscale,that support the extreme observed hourly rainfall.Results show that the extreme rainfall occurred in an environment characteristic of warm-sector heavy rainfall,with abundant warm moist air transported from the ocean by an abnormally northward-displaced western Pacific subtropical high and Typhoon In-Fa(2021).However,rather than through back building and echo training of convective cells often found in warm-sector heavy rainfall events,this extreme hourly rainfall event was caused by a single,quasi-stationary storm in Zhengzhou.Scale separation analysis reveals that the extreme-rainproducing storm was supported and maintained by the dynamic lifting of low-level converging flows from the north,south,and east of the storm.The low-level northerly flow originated from a mesoscale barrier jet on the eastern slope of the Taihang Mountain due to terrain blocking of large-scale easterly flows,which reached an overall balance with the southerly winds in association with a low-level meso-β-scale vortex located to the west of Zhengzhou.The large-scale easterly inflows that fed the deep convection via transport of thermodynamically unstable air into the storm prevented the eastward propagation of the weak,shallow cold pool.As a result,the convective storm was nearly stationary over Zhengzhou,resulting in record-breaking hourly precipitation.

Extending Extreme Programming User Stories to Meet ISO 9001 Formality Requirements

For software organizations needing ISO 9001 certification, including those that have adopted agile methodologies, it is important that their software life cycle processes be able to manage the requirements imposed by this certification standard. However, the user stories in the XP agile methodology do not provide auditors with enough evidence that certain steps and activities have been performed in compliance with ISO 9001. This paper proposes an extension to the user story, based on four sub processes related to the CMMI-DEV model: 1) identification of the source of the user story;2) categorization of the non functional requirements;3) identification of the user story relationships;and 4) prioritization of the user stories. These sub processes are aligned with the XP release planning phase, and enhance the ability of user stories to accumulate the information that is mandatory for achieving ISO 9001 certification.

Stratosphere-troposphere synergetic effect on the extreme low-temperature event over China in late November 2022

In late November 2022,most regions in China were hit by a strong northwest-path cold wave,bringing a high-hazard extreme low-temperature event(ELTE).Several parts of Northwest China experienced extremely low temperatures and record-breaking snow depths.A stratosphere-troposphere synergetic effect was suggested to be closely related to the ELTE according to a diagnostic analysis.On the one hand,the concurrent establishment of two blockings in Europe-Northeast Atlantic and North Pacific led to a polar vortex split at the tropopause,and the Arctic Oscillation phase subsequently turned negative.An airflow with high potential vorticity(PV)was squeezed out of the Arctic.Meanwhile,a high-PV air that originated from the lower stratospheric Arctic was conveyed southwards to the western Siberian Plain along the sloping isentropic surface.This condition triggered a tropospheric response in which the East Asia trough deepened due to the intensified cyclonic circulation induced by the high-PV intrusion.On the other hand,downward propagation of stratospheric anomalies accompanied by stratospheric polar vortex displacement and split was observed in mid-and late November,respectively.Changes in stratospheric circulation contributed to enhanced blockings over Europe-Northeast Atlantic in the lower stratosphere or upper troposphere.As a result,the inverted omega-shaped circulation pattern was formed in the middle to upper troposphere,and it consisted of the intensified East Asia trough and two blockings in the upstream and downstream regions.The high-PV air upstream of the East Asia trough was advected to China,which directly led to the outbreak of the ELTE.The establishment of double blockings and the displacement or split of the stratospheric polar vortex can be efficient signals for cold-event prediction in China.This study provides novel insights into the cause of ELTEs under warming climates in the future.

Sampling Geostatistical Structures in Extremal Framework

Geostatistics of extreme values makes it possible to model the asymptotic behavior of random phenomena that depend on time or space. In this paper, we propose new models of the extremal coefficient of a stationary random field where the cumulative distribution is associated with a multivariate copula. More precisely, some models of extensions of the extremogram and these derivatives are built in a spatial framework. Moreover, both these two geostatistical tools are modeled using the extremal variogram which characterizes the asymptotic stochastic behavior of the phenomena.

中国极端天气气候研究——“地球系统与全球变化”重点专项项目简介及最新进展

全球变暖背景下,极端天气气候事件频发,并表现出群发性、持续性、复合性等特点,不可预测性增加;持续性强降水、极端低温、复合型极端高温干旱、群发性热浪和台风等极端天气气候事件对我国经济社会和可持续发展影响巨大。然而,上述极端天气气候事件的新特征、关键过程和机理尚不完全清楚,重大极端事件的预报预测水平亟待提升。文章首先简要介绍“地球系统与全球变化”重点专项项目“中国极端天气气候事件的形成机理及其预测和归因”的基本情况。项目拟在分析全球变化背景下对我国造成重大影响的极端天气气候事件新特征的基础上,深入研究多尺度海-陆-气耦合过程影响极端天气气候事件的机理,挖掘极端天气气候事件次季节-季节预测的前兆信号;发展动力与物理统计相结合的极端事件预测新方法,研制针对中国极端事件的新一代高分辨率数值预报与检测归因系统。文章重点总结了自2022年12月项目立项至今取得的最新研究成果和进展。

近62 a三峡地区区域性暴雨过程气候特征及长期变化规律

【目的】充分认识三峡地区区域暴雨过程的气候特征及长期变化规律对于科学防汛以及合理利用水资源具有重要意义。【方法】基于三峡地区33个国家级气象观测站1961—2022年逐日降水量资料和目前重庆市气候中心业务采用的区域性暴雨过程监测指标,对三峡地区区域性暴雨过程进行客观识别,并利用多种数理统计方法分析区域性暴雨过程的气候特征和长期变化规律。【结果】结果表明:(1)三峡地区近三分之二的暴雨以区域性过程形式出现,平均每年区域性暴雨过程有8.4次,主要出现在5—9月,尤以6—7月为集中发生时段。区域性暴雨过程首次开始日期多年平均为5月8日,末次结束日期为9月17日。平均每次过程的暴雨覆盖范围为8.6站,持续时间1.3 d,平均暴雨强度为74.7 mm/d。(2)三峡地区区域性暴雨过程年频次存在2~3 a和8 a左右的变化周期,年平均区域性暴雨过程覆盖范围存在4~6 a和8~11 a周期变化。(3)近62 a三峡地区区域性暴雨过程的首次开始日期显著提前,末次结束日期无明显变化,发生期显著变长;发生频次没有明显变化趋势、平均持续时间、平均覆盖范围、平均综合强度也均没有明显变化趋势,但平均暴雨强度呈增强趋势。(4)近62 a,三峡地区区域性暴雨过程的各项指标均未发生突变现象。【结论】研究成果为三峡地区防汛减灾、水资源管理以及回应三峡工程对局地气候影响的社会关切等提供科学支撑。

考虑极端天气冲击过程的风电机组竞争失效可靠性评估

针对风电机组的运行可靠性易受极端天气影响的问题,提出了一种考虑极端天气冲击过程的风电机组竞争失效可靠性评估方法。同时考虑风电机组自然退化、极端天气冲击导致的瞬时退化以及极端天气持续过程产生的加速退化,构建极端天气下的风电机组综合退化模型;考虑风电机组退化过程对其耐冲击性能的影响,建立风电机组竞争失效可靠度模型以评估风电机组可靠性;基于我国北方某风电场工程数据和极端天气历史数据评估了某2 MW风电机组的可靠性并进行了参数灵敏度分析。结果显示,到第5年时,仅考虑自然退化的方法评估风电机组可靠度为0.84,而考虑极端天气冲击过程的方法评估风电机组可靠度为0.178,后者更加符合工程实际。通过模型参数的灵敏度分析发现,运行时间超过3年后,退化失效开始逐渐影响风电机组的可靠性。

基于XGBoost增量实现业务流程执行结果的预测性监控方法

随着工业制造业务流程智能化提升,以预测执行结果为目标的监控技术成为必需。该技术基于历史执行构建预测模型,从而对正在执行的流程进行结果预测。但现有研究假定流程执行行为一直保持不变,实际上流程在运行中常发生变化(即流程执行发生漂移),因此预测模型也需要适应这种漂移。针对这种情况,受到在线学习思想的启发,提出了基于XGBoost增量实现以流程执行结果为目标的预测流程监控技术,并分别在真实数据集和合成数据集上进行了大量的实验。实验结果表明,基于XGBoost的增量学习技术能够很好地为工业制造真实场景中的预测性流程监控提供一种有效的解决方案。

基于多模型融合策略的温室番茄光合速率预测方法

温室番茄光合速率的准确预测对于番茄的生长和产量评估具有重要意义。然而,由于温室环境的复杂性和多变性,传统的光合速率预测模型往往难以满足精准预测的需求。因此,为了进一步提高预测模型的准确性和稳定性,本研究提出了一种基于多模型融合策略的温室番茄光合速率预测方法。首先,采集温湿度、光照强度、CO_(2)浓度不同组合下的番茄光合速率,构建样本集,并采用五折交叉验证法(Cross-Validation)对数据进行预处理。以预处理的数据为基础,分别基于粒子群优化支持向量机(PSO-SVR)、布谷鸟优化极限学习机(CS-ELM)和北方苍鹰优化高斯过程回归(NGO-GPR)算法建立番茄光合速率预测模型对光合速率进行初步预测,然后采用Stacking算法通过基于决策树的集成学习模型(XGBoost)组合各基础模型的预测结果,进而实现多模型融合。仿真分析结果表明,与单一预测模型相比,基于多模型融合的光合速率预测模型充分发挥了各基础模型的优势,可以进一步提高光合速率预测的准确性和稳定性,该模型验证集MAE为0.569 7μmol/(m^(2)·s),RMSE为0.721 4μmol/(m^(2)·s)。因此,本文提出的方法在温室作物光合速率预测方面具有一定的优势,可为温室番茄等作物光环境优化调控提供一定的理论基础和技术支撑。