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Enhancing the photo-luminescence stability of CH_(3)NH_(3)PbI_(3) film with ionic liquids

Chinese Physics B 2022年第3期31卷 550-554页

作者： Weifeng Ma Chunjie Ding Nasrullah Wazir xianshuang wang Denan Kong An Li Bingsuo Zou Ruibin Liu Beijing Key Laboratory of Nanophotonics and Ultrafine Optoelectronic Systems School of PhysicsBeijing Institute of TechnologyBejing 100081China

The methylammonium lead triiodide(CH_(3)NH_(3)PbI_(3))-based perovskite shows a great alluring prospect in areas of solar cells, lasers, photodetectors, and light emitting diodes owing to their excellent optical and electrical advantages. However,it is very sensitive to the surrounding oxygen and moisture, which limits its development seriously. It is urgent to spare no effort to enhance its optical and electrical stability for further application. In this paper, we synthesize the MAPbI_(3) perovskite film on the glass substrate with/without the ionic liquid(IL) of 1-Butyl-3-methylimidazolium tetrafluoroborate(BMIMBF_(4)) by a simple two-step sequential solution method. The additive of BMIMBF_(4)can improve the quality of crystal structure. Moreover, the photo-luminescence(PL) intensity of MAPbI_(3) film with BMIMBF_(4) is much stronger than the pure MAPbI_(3) film after a week in the air, which is almost ten-fold of the pure one. Meanwhile, under the illumination of 405-nm continuous wave(CW) laser, the fluorescent duration of the MAPbI_(3) film with BMIMBF_(4) is approximately 2.75 min, while the pure MAPbI;film is only about 6 s. In fact, ionic liquid of BMIMBF_(4) in the perovskite film plays a role of passivation, which prevents the dissolution of MAPbI_(3) into CH_(3)NH_(3)and PbI_(2) and thus enhances the stability of environment. In addition, the ionic liquid of BMIMBF;possesses high ionic conductivity, which accelerates the electron transport, so it is beneficial for the perovskite film in the areas of solar cells, photodetectors, and lasers. This interesting experiment provides a promising way to develop the perovskite’s further application.

关键词： CH_(3)NH_(3)PbI_(3)perovskite film photo-luminescence BMIMBF_(4)ionic liquid

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央行预期管理、通胀波动与银行风险承担

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经济研究 2015年第10期50卷 34-48页

作者：汪莉王先爽复旦大学经济学院邮政编码200433

自"预期管理"概念提出以来,我国央行预期管理政策在降低经济不确定性、减少通货膨胀及其预期波动中的作用得到了越来越多的肯定,然而鲜有研究对预期管理的金融稳定效应进行解释。为此,本文通过通胀预期和央行预期管理信息的引入,在"信... 详细信息

自"预期管理"概念提出以来,我国央行预期管理政策在降低经济不确定性、减少通货膨胀及其预期波动中的作用得到了越来越多的肯定,然而鲜有研究对预期管理的金融稳定效应进行解释。为此,本文通过通胀预期和央行预期管理信息的引入,在"信息粘性"模型基础上估算出了我国通胀预期的波动数据并以此考察央行预期管理政策对通胀预期波动和银行风险承担的影响。研究结果表明:自2007年以来我国央行预期管理政策在降低通胀预期波动中的作用日益显现且在危机时期更为明显;因央行预期管理政策而降低的通胀预期波动幅度与银行风险承担间总体呈现倒"U"型关系;通胀预期波动不确定性的降低和银行货币政策预测能力的提高更有可能在非危机时引起风险低估和银行风险承担的增加;不同类型商业银行因预期管理政策而降低的通胀预期波动与银行风险承担间关系的临界值也存在差异,上市银行更有可能落入倒"U"型曲线左侧的上升区间。因此,央行预期管理政策需要在熨平经济波动和维持金融稳定间进行权衡并兼顾银行风险承担的异质性特征。

关键词：预期管理通胀预期波动银行风险承担

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Low-threshold and narrow-emission random lasing in a self-assembly TiN nanoparticle-doped carbon quantum dot/DCM nanowire composite

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Photonics Research 2022年第9期10卷 2239-2246页

作者： JING LYU XINYU ZHANG LEI CAI LI TAO WEIFENG MA AN LI YE TIAN YUNSONG YIN DENAN KONG WEN YI xianshuang wang RUIBIN LIU Beijing Key Laboratory of Nano-photonics and Ultrafine Optoelectronic Systems School of PhysicsBeijing Institute of TechnologyBeijing 100081China Yangtze Delta Region Academy of Beijing Institute of Technology Jiaxing 314000China Jiangsu Key Laboratory for Carbon-Based Functional Materials&Devices Institute of Functional Nano&Soft Materials(FUNSOM)Soochow UniversitySuzhou 215123China

The random lasing in quantum dot systems is in anticipation for widespread applications in biomedical therapy and image recognition,especially in random laser devices with high brightness and high ***,low-threshold,narrowband emission,and stable random lasing is realized in carbon quantum dot(CQD)/DCM nanowire composite-doped TiN nanoparticles,which are fabricated by the mixture of carbon quantum dots and self-assembly DCM dye *** F?rster resonance energy transfer process results in a high luminescence efficiency for the composite of carbon dots and DCM nanowires,allowing significant random lasing actions to emerge in CQD/DCM composite as TiN particles are doped that greatly enhance the emission efficiency through the plasmon resonance and random ***,sharp and low-threshold random lasing is finally realized and even strong single-mode lasing occurs under higher pumping energy in the TiN-doped CQD/DCM *** work provides a promising way in high monochromaticity random laser applications.

关键词： pumping lasing random

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基于激光诱导击穿光谱的茶叶品种快速分类

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中国激光 2019年第3期46卷 277-283页

作者：徐向君王宪双李昂泽何雅格柳宇飞何锋郭伟刘瑞斌北京理工大学物理学院北京100081 宝瑞激光科技(常州)有限公司江苏常州213000

在提取激光诱导击穿光谱(LIBS)全部特征峰的基础上,利用支持向量机建立了有效的茶叶分类模型。采集了15种茶叶样品的有效LIBS光谱数据(190～720 nm),运用窗口平移平滑和峰位漂移函数修正对光谱进行了预处理,再结合主成分分析降维,对绿... 详细信息

在提取激光诱导击穿光谱(LIBS)全部特征峰的基础上,利用支持向量机建立了有效的茶叶分类模型。采集了15种茶叶样品的有效LIBS光谱数据(190～720 nm),运用窗口平移平滑和峰位漂移函数修正对光谱进行了预处理,再结合主成分分析降维,对绿茶、红茶、白茶实现了98.3%的识别率;对同一种类中不同品种的茶叶也实现了较好的识别。研究结果表明,LIBS在茶叶品种快速识别应用中具有较好的前景。

关键词：光谱学激光诱导击穿光谱茶叶品种快速分类光谱预处理主成分分析支持向量机

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小样本量复合肥中氮磷钾高精度预测光谱方法

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中国激光 2021年第23期48卷 152-160页

作者：马骁李安王宪双孔德男邱苏玲何雅格殷允嵩柳宇飞刘瑞斌北京理工大学物理学院北京100081 宝瑞激光科技(常州)有限公司江苏常州213000

采用激光诱导击穿光谱(LIBS)技术对复合肥样品中氮(N)、磷(P)和钾(K)等营养元素进行定量分析。实验中一共选取20个样品,由于样品量较少,为了提高预测精度,采取一种新的数据提取方式来建立训练集和预测集。利用PLS结合主成分分析(PCA)为... 详细信息

采用激光诱导击穿光谱(LIBS)技术对复合肥样品中氮(N)、磷(P)和钾(K)等营养元素进行定量分析。实验中一共选取20个样品,由于样品量较少,为了提高预测精度,采取一种新的数据提取方式来建立训练集和预测集。利用PLS结合主成分分析(PCA)为训练集的光谱数据建立定标模型,定标过程中选取12个主成分。N、P、K三种元素定标模型的决定系数分别为0.99、0.98、0.99;20个样品中N、P、K元素含量(质量分数,下同)预测的平均相对误差分别为2.33%、0.70%、3.00%。之后对定标模型的鲁棒性进行检验,其中N、P的平均相对误差大多维持在12%以下。采用基于统计学原理的数据抽取方式扩充样本光谱数据后,与未扩充时相比,被测元素含量的平均相对误差降幅均在10%以上。实验结果表明,当样本数量较少时,利用所提的数据提取方法结合PLS定量分析可以提高检测的准确度,实现复合肥样品中N、P、K等营养元素的快速检测。

关键词：光谱学激光诱导击穿光谱复合肥偏最小二乘法小样本量

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基于激光诱导击穿光谱的矿石中铁含量的高准确度定量分析

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中国激光 2021年第16期48卷 195-204页

作者：邱苏玲李安王宪双孔德男马骁何雅格殷允嵩柳宇飞石丽洁刘瑞斌北京理工大学物理学院北京100081 宝瑞激光科技(常州)有限公司江苏常州213000

基于激光诱导击穿光谱(LIBS)对铁矿石、锰矿石和铬矿石中的Fe元素进行定量分析。由于矿石成分复杂,采取一系列的光谱预处理来降低由激光能量波动及样品不稳定烧蚀所造成的光谱波动。本文将分类和定量分析方法结合,首先通过支持向量机对... 详细信息

基于激光诱导击穿光谱(LIBS)对铁矿石、锰矿石和铬矿石中的Fe元素进行定量分析。由于矿石成分复杂,采取一系列的光谱预处理来降低由激光能量波动及样品不稳定烧蚀所造成的光谱波动。本文将分类和定量分析方法结合,首先通过支持向量机对光谱进行分类以避免不同类矿石间的基体效应。然后通过相关性变量筛选偏最小二乘回归分析(R-PLS)改进算法进行分析,发现三类矿石的预测集方均根误差分别降至0.975%、0.418%、0.123%,平均相对误差分别降至1.46%、6.72%和1.09%。实验结果表明,矿石分类后再进行相关性变量筛选偏最小二乘回归分析的方法可以有效提升预测准确度,为矿石成分在线检测的应用提供了可靠依据。

关键词：光谱学激光诱导击穿光谱矿石定量分析偏最小二乘回归主成分分析支持向量机

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Constraints on holographic QCD phase transitions from PTA observations

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Science China(Physics,Mechanics & Astronomy) 2025年第1期Mechanics & Astronomy) .卷 71-78页

作者： Song He Li Li Sai wang Shao-Jiang wang Center for Theoretical Physics and College of Physics Jilin University School of Physical Science and Technology Ningbo University Max Planck Institute for Gravitational Physics (Albert Einstein Institute) CAS Key Laboratory of Theoretical Physics Institute of Theoretical Physics Chinese Academy of Sciences School of Fundamental Physics and Mathematical Sciences Hangzhou Institute for Advanced StudyUniversity of Chinese Academy of Sciences (UCAS) School of Physical Sciences University of Chinese Academy of Sciences (UCAS) Theoretical Physics Division Institute of High Energy Physics Chinese Academy of Sciences

The underlying physics of QCD phase transition in the early Universe remains largely unknown due to its strong-coupling nature during the quark-gluon plasma/hadron gas transition, yet a holographic model has been proposed to quantitatively fit the lattice QCD data while with its duration of the first-order phase transition(FoPT) left undetermined. At specific baryon chemical potential, the first-order QCD phase transition agrees with the observational constraint of baryon asymmetry. It, therefore, provides a scenario for phase transition gravitational waves(GWs) within the standard model of particle physics. If these background GWs could contribute dominantly to the recently claimed common-spectrum red noise from pulsar timing array(PTA) observations, the duration of this FoPT can be well constrained, and the associated primordial black holes are still allowed by current observations.

关键词： pulsar timing array QCD phase transition gravitational waves primordial black holes

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Rational modulation of fluorophosphate cathode by anionic groups to reduce the polarization behavior for fast-charging sodium-ion batteries

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Journal of Energy Chemistry 2025年第1期100卷 509-521页

作者： Xinyuan wang Fan Zhang Xingyu Zhou Qian wang Changyu Liu Yangyang Liu Hui wang Xiaojie Liu Key Laboratory of Synthetic and Natural Functional Molecule of the Ministry of Education College of Chemistry & Materials Science Northwest University

Na3V2（PO4）2O2F （VP） is recognized as a promising cathode material for sodium-ion batteries due to its stable structural framework and high specific *** functional theory （DFT） and finite element simulations show that incorporating SO42-into VP decreases its band gap,lowers the migration energy barrier,and ensures a uniform Na+concentration gradient and stress distribution during charge and discharge ***,the average Na+diffusion coefficient of Na3V2（PO4）1.95（SO4）0.05O2F（VPS-1） is roughly double that of VP,leading to enhanced rate capability (80 C,75.5 mAh g-1) and cycling stability (111.0 mAh g-1capacity after 1000 cycles at 10 C current density) for ***-1 exhibits outstanding fast-charging capabilities,achieving an 80%state of charge in just 8.1 *** assembled VPS-1//SbSn/NPC full cell demonstrated stable cycling over 200 cycles at a high 5 C current,maintaining an average coulombic efficiency of 95.35%.

关键词： Anionic group modulation Polarization behavior Fast-charging Sodium-ion battery Fluorophosphate Cathode

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Critical effects on the photosynthetic efficiency and stem sap flow of poplar in the Yellow River Delta in response to soil water

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Journal of Forestry Research 2021年第6期32卷 2485-2498页

作者： Changxi wang Huanyong Liu Jiangbao Xia xianshuang Xing Shuyong Zhang State Forestry and Grassland Administration Key Laboratory of Silviculture in Downstream Areas of the Yellow River Shandong Agricultural UniversityTaian 271018People’s Republic of China Shandong Key Laboratory of Eco-Environmental Science for the Yellow River Delta Binzhou UniversityBinzhou 256603People’s Republic of China Hydrographic Office of Shandong Province Jinan 250002People’s Republic of China

To explore the critical relationships of photosynthetic efficiency and stem sap flow to soil moisture,two-year-old poplar saplings were selected and a packaged stem sap flow gauge,based on the stem-heat balance method,and a CIRAS-2 portable photosynthesis system were *** results show that photosynthetic rates(P_(n)),transpiration rates(T_(r)),instantaneous water use efficiency(WUE)and the stem sap flow increased initially and then decreased with decreasing soil water,but their critical values were *** turning point of relative soil water content(W_(r))from stomatal limitation to nonstomatal limitation of P_(n)was 42%,and the water compensation point of P_(n)was 13%.Water saturation points of P_(n)and T_(r)were 64%and 56%,respectively,and the WUE was 71%.With increasing soil water,the apparent quantum yield(AQY),light saturation point(LSP)and maximum net photosynthetic rate(P_(n)max)increased first and then decreased,while the light compensation point(LCP)decreased first and then *** W_(r)was 64%,LCP reached a lower value of 30.7µmol m^(-2)s^(-1),and AQY a higher value of 0.044,indicating that poplar had a strong ability to utilize weak *** W_(r)was 74%,LSP reached its highest point at 1138.3µmol·m^(-2)s^(-1),indicating that poplar had the widest light ecological amplitude and the highest light utilization *** sap flow and daily sap flow reached the highest value(1679.7 g d^(-1))at W_(r)values of 56%and 64%,respectively,and then declined with increasing or decreasing W_(r),indicating that soil moisture significantly affected the transpiration water-consumption of *** water was divided into six threshold grades by critical values to maintain photosynthetic efficiency at different levels,and a W_(r)of 64-71%was classified to be at the level of high productivity and high *** this range,poplar had high photosynthetic capacity and efficient physiological characteristics for water *** saplings had c

关键词： Gas exchange parameters Sap flow Soil moisture Water use efficiency Yellow River Delta

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Role of iron ore in enhancing gasification of iron coke:Structural evolution,influence mechanism and kinetic analysis

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International Journal of Minerals,Metallurgy and Materials 2025年第1期32卷 58-69页

作者： Jie wang Wei wang Xuheng Chen Junfang Bao Qiuyue Hao Heng Zheng Runsheng Xu School of Chemistry and Materials Science Hubei Engineering UniversityXiaogan 432000China Key Laboratory for Ferrous Metallurgy and Resources Utilization of Ministry of Education Wuhan University of Science and TechnologyWuhan 430081China Institue of Ironmaking Technology Baosteel Central Research InstituteShanghai 201999China State Key Laboratory of Advanced Metallurgy University of Science and Technology BeijingBeijing 100083China

The utilization of iron coke provides a green pathway for low-carbon *** uncover the influence mechanism of iron ore on the behavior and kinetics of iron coke gasification,the effect of iron ore on the microstructure of iron coke was ***,a comparative study of the gasification reactions between iron coke and coke was conducted through non-isothermal thermogravimetric *** findings indicate that compared to coke,iron coke exhibits an augmentation in micropores and specific surface area,and the micropores further extend and *** provides more adsorption sites for CO_(2) molecules during the gasification process,resulting in a reduction in the initial gasification temperature of iron *** the heating rate in non-isothermal gasification can enhance the reactivity of iron *** metallic iron reduced from iron ore is embedded in the carbon matrix,reducing the orderliness of the carbon structure,which is primarily responsible for the heightened reactivity of the carbon *** kinetic study indicates that the random pore model can effectively represent the gasification process of iron coke due to its rich pore ***,as the proportion of iron ore increases,the activation energy for the carbon gasification gradually decreases,from 246.2 kJ/mol for coke to 192.5 kJ/mol for iron coke 15wt%.

关键词： low-carbon ironmaking iron coke gasification structural evolution kinetic model

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