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Mixed-cation chiral perovskites displaying warm-white circularly polarized luminescence

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Science China Chemistry 2023年第5期66卷 1425-1434页

作者： hua-Li Liu hua-yang Ru Meng-En Sun Zhao-yang Wang Shuang-Quan Zang Henan Key Laboratory of Crystalline Molecular Functional Materials Henan International Joint Laboratory of Tumor Theranostical Cluster MaterialsGreen Catalysis Centerand College of ChemistryZhengzhou UniversityZhengzhou 450001China

Chiral perovskites with exceptional structural flexibility and optoelectrical properties are regarded as promising materials for optoelectronic and spintronic ***,the effects of achiral organic ligands on the chiroptical activity of chiral perovskites have been rarely ***,we present four one-dimensional lead bromide perovskites R-/S-(AMP)_(2)Pb_(3)Br_(10)(1-R and 1-S)with mono-cation and R-/S-AMP(DMA)Pb Br_(5)(2-R and 2-S)with mixed-cation templated by chiral R-/S-2-aminomethylpyrrolidine(R-/S-AMP)and achiral dimethylammonium(DMA).All four compounds demonstrate broadband emissions from self-trapped excitons(STEs).Derived from the stronger chirality transfer synergistically induced by achiral DMA,amplified bathochromically-shifted circular dichroism signals and strong warm-white circularly polarized emissions have been observed in 2-R and *** mixed-cation structural engineering provides a new route toward developing chiral perovskites for optoelectronic applications.

关键词： chiral perovskites achiral cations chirality transfer circular dichroism circularly polarized luminescence

Stability of second-order stochastic neutral partial functional differential equations driven by impulsive noises

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Science China(Information Sciences) 2016年第11期59卷 117-127页

作者： Feng JIANG hua yang Yi SHEN School of Statistics and Mathematics Zhongnan University of Economics and Law School of Automation Huazhong University of Science and Technology School of Mathematics and Computer Science Wuhan Polytechnic University

This paper investigates the stability of second-order stochastic neutral partial functional differential equations driven by impulsive noises. Some sufficient conditions ensuring pth moment exponential stability of the second-order stochastic neutral partial functional differential equations driven by impulsive noises are obtained by establishing a new impulsive-integral inequality. These existing results are generalized and improved by the present study. Finally, an example is given to show the effectiveness of our results.

关键词： second-order stochastic neutral partial functional differential equations exponential stability impulsive noises sine family cosine family

Tracing the behaviour of hexachlorobenzene in a paddy soil-rice system over a growth season

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Journal of Environmental Sciences 2008年第1期20卷 56-61页

作者： yang hua ZHENG Minghui ZHU Yongguan Research Center for Eco-Environrnental Sciences Chinese Academy of Sciences Beijing 100085 China.

Hexachlorobenzene （HCB）, a persistent organic pollutant （POP）, has been found in paddy soils. To improve the understanding of HCB contamination in paddy soils, a laboratory simulative study was carried out to investigate the behavior of HCB in a paddy soil and rice plants. This study was divided into three experiments. First, an experiment aimed to examine the evaporation of HCB in paddy soil. In the second experiment, rice was planted in 10 mg/kg HCB contaminated soil and after pot culture at 3, 6, 9, and 27 weeks （at maturity）, both soil and plant samplings were scheduled to be sampled. The soil samples comprised rhizosphere soil, nortrhizosphere soil, and unplanted contaminated soil, whereas plant samples included shoots, roots, and rice grains （dehusked）. Lastly, in this part, HCB in xylem saps was designed to be examined. The results showed that （1） the HCB translocation from paddy soil to rice by vaporization; （2） the HCB concentration in rice grains was surprisingly high; （3） the observed HCB decrease in rice rhizosphere offers a potential means for in situ HCB degradation; （4） HCB might not be transported along transpiration in rice.

关键词： HCB paddy soil rice rhizosphere xylem sap

Research on parafoil stability using a rapid estimate model

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Chinese Journal of Aeronautics 2017年第5期30卷 1670-1680页

作者： hua yang Lei SONG Weifang CHEN School of Aeronautics and Astronautics Zhejiang University School of Aeronautic Science and Engineering Beihang University

With the consideration of rotation between canopy and payload of parafoil system, a four-degree-of-freedom（4-DOF） longitudinal static model was used to solve parafoil state variables in straight steady flight. The aerodynamic solution of parafoil system was a combination of vortex lattice method（VLM） and engineering estimation method. Based on small disturbance assumption,a 6-DOF linear model that considers canopy additional mass was established with benchmark state calculated by 4-DOF static model. Modal analysis of a dynamic model was used to calculate the stability parameters. This method, which is based on a small disturbance linear model and modal analysis, is high-efficiency to the study of parafoil stability. It is well suited for rapid stability analysis in the preliminary stage of parafoil design. Using this method, this paper shows that longitudinal and lateral stability will both decrease when a steady climbing angle increases. This explains the wavy track of the parafoil observed during climbing.

关键词： Dynamic model Motion mode Parafoil Small-disturbance theory Stability

Water Dissociation Phenomena on a Bipolar Membrane──Current-voltage Curve in Relation with IonicTransport and Limiting Current Density

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Chemical Research in Chinese Universities 2001年第4期17卷 457-464页

作者： XU Tong-wen yang Wei-hua Department of Applied Chemistry University of Science and Technology of ChinaHefei 230026P.R.China

The water dissociation mechanism on a bipolar membrane under the electrical field was investigated and characterized in terms of ionic transport and limiting current density. It is considered that the depletion layer exists at the junction of a bipolar membrane, which is coincided with the viewpoint of the most literatures, but we also consider that the thickness and conductivity of this layer is not only related with the increase of the applied voltage but also with the limiting current density. Below the limiting current density, the thickness of the depletion layer keeps a constant and the conductivity decreases with the increase of the applied voltage; while above the limiting current density, the depletion thickness will increase with the increase of the applied voltage and the conductivity keeps a very low constant. Based on the data reported in the literatures and independent determinations, the limiting current density was calculated and the experimental curves Ⅰ-Ⅴ in the two directions were com

关键词： Bipolar membrane Water dissociation Ionic transport Limiting current density

High coercivity cobalt carbide nanoparticles as electrocatalysts for hydrogen evolution reaction

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Nano Research 2022年第5期15卷 3901-3906页

作者： Yaqin Qie Yixuan Liu Fanqi Kong Zhilin yang hua yang College of Chemistry Jilin UniversityChangchun 130012China

Cobalt carbide nanoparticles(NPs),as a typical carbide material,have attracted extensive attention in the fields of magnetism and ***,we adopted a modified solution route by pyrolysis long-chain amines at high temperatures to obtain Co_(2)C NPs,in which different forms of Co NPs were used as *** results reveal that no matter what the structure of the precursor and the type of long-chain amine,single-phase Co_(2)C NPs with good crystallinity are *** the same time,carbonization of hexagonal close packed(hcp)cobalt as the precursor gives the materials high magnetic anisotropy,exhibiting a large coercivity(~1,300 Oe)on the *** terms of catalytic properties,benefiting from intrinsically high activity of Co_(2)C NPs,the material demonstrates superior hydrogen evolution reaction(HER)performance,with optimal overpotential as low as 73 mV at the current density of 10 mA·cm^(-2).This provides new ideas for the further development of transition metal carbides(TMCs)and the improvement of their magnetic and electrocatalytic properties.

关键词： cobalt carbide nanoparticles solution route hard magnetic properties hydrogen evolution reaction

Simple intra-signal-interference removing detector for HE-DCSK

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The Journal of China Universities of Posts and Telecommunications 2013年第6期20卷 102-108页

作者： yang hua JIANG Guo-ping College of Electronic Science and Engineering Nanjing University of Posts and Telecommunications College of Automation Nanjing University of Posts and Telecommunications

In this paper, a novel simple detector is designed to remove the intra-signal interference in high efficiency differential chaos shift keying （HE-DCSK） modulation scheme. With the help of data bit estimated before correlation detection, this new detector could remove the modulated chaotic segment that would form intra-signal interference component in the correlator output from every received information-bearing signal in HE-DCSK, leading to greatly and effectively improved system bit error rate （BER） performance. The effectiveness of this proposed detector is studied analytically based on the numerical integration method and evaluated by computer simulation in additive-white-Gaussian- noise （AWGN） channel. Simulation results reveal that the proposed detector can dramatically improve the overall BER performance of HE-DCSK even at relatively low signal noise ratio （SNR） levels.

关键词： chaos communications intra-signal interference removing high-efficiency differential chaos shift keying bit error rate

Experimental Observation of Constructive Quantum Interference via Hybrid Excitation in an Na2-Na System

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Chinese Physics Letters 2002年第3期19卷 334-337页

作者： yang Xi-hua, Li Yong-Fang Key Laboratory of Optical and Magnetic Resonance Spectroscopy Department of Physics East China Normal University Department of Physics Xi"an JiaoTong University Department of Physics Shaanxi Normal University

We report on an experimental observation of constructive quantum interference between two atomic transition pathways 3P1/2-5S (or 4D) and 3P3/2-5S (or 4D) via equal-frequency hybrid excitation and collision-aided radiative excitation in an Na2-Na system. Through the special excitation processes, constructive quantum interference is realized for a Λ-type quantum-beat configuration with a widely-spaced doublet (about 17 cm^-1) in the excited sodium atom driven by one laser. The dependences of quantum interference on the argon buffer gas pressure and sample temperature are also examined.

关键词： Excited states

Evaluation method and empirical application of human activity suitability of land resources in Qinghai-Tibet Plateau

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Journal of Geographical Sciences 2023年第7期33卷 1397-1418页

作者： XU Yong WANG Lijia yang hua Key Laboratory of Regional Sustainable Development Modelling Institute of Geographic Sciences and Natural Resources ResearchCASBeijing 100101China University of Chinese Academy of Sciences Beijing 100049China

The current suitability evaluation methods for land resources human activity in China suffer from theoretical deficiencies related to fundamental data accuracy,elevation and slope classification,and suitability class *** application of these methods is also hindered by excessive evaluation indicators,data acquisition difficulties,and limited applicability to high altitude *** address these issues,this paper proposes a technical evaluation framework for the Qinghai-Tibet Plateau(QTP) that employs selected key parameters varying with elevation and slope to establish grid-scale evaluation models for construction land suitability(CLS) and arable land suitability(ALS).A generalized algorithm is then proposed for key parameters such as air density,air temperature,slope suitability for construction,and soil erosion resistance of sloping arable *** research is conducted using Milin County in southeast Tibet as a case study,with interval measurements of 100 m in elevation and 1° in *** evaluation model is tested using grid accuracies of 30 m,50 m,100 m,250 m,500 m,and 1000 *** results reveal that:Firstly,the CLS and ALS can be categorized into five classes:highly suitable,suitable,moderately suitable,marginally suitable,and unsuitable,with varying area ratios under different grid ***,existing construction lands in Milin County are mainly distributed in suitable,highly suitable,and moderately suitable CLS classes,accounting for over 94% of the total area studied under different grid *** arable land is mainly distributed in suitable,highly suitable,and moderately suitable ALS classes,accounting for over 96%.Thirdly,the empirical research in Milin County indicates that the evaluation method,quantitative model,and parameters algorithm for evaluating human activity suitability of land resources on the QTP are feasible and applicable,with a recommended grid accuracy within 100 m and a maximum of 250 ***,t

关键词： human activity evaluation model construction land suitability arable land suitability land resource Qinghai-Tibet Plateau