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Rare earth inorganic-organic hybrid compounds based on Keggin-type polyoxometalate {SiW_(12)} with fast-responsive photochromism and switchable luminescence properties

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Journal of Rare Earths 2024年第2期42卷 286-292,I0003页

作者： Hong Cui Yanli Yang Xue Bai Xu Han Wensha zhang Ying Lu shuxia Liu Key Laboratory of Polyoxometalate and Reticular Material Chemistry of the Ministry of Education College of ChemistryNortheast Normal UniversityChangchun 130024China

Four rare earth inorganic-organic hybrid compounds based on Keggin-type polyoxometalate {SiW_(12)}with general formula [{RE(DMF)_(4)(H_(2)O)_4RE(DMF)_(6)}_(2){SiW_(12)O_(40)}_(3)](RE = La(1),Pr(2),Sm(3),Eu(4),DMF=N,N-dimethylformamide) were synthesized by the conventional solution method.Structure analyses indicate that four compounds are isostructural and are all built from three [SiW_(12)O_(40)]^(4-) polyoxoanions and DMF ligands linked by RE^(3+).Compounds 1-4 are extremely sensitive to UV light and present excellent photochromic properties,in which the coloring and fading time of samples are both no more than 2 min,and the reversible coloring-fading process can be repeated for at least 10 cycles with little fatigue,suggesting that compounds 1-4 can be a series of fast-responsive and durable photochromic materials.Moreover,the solid-state photoluminescence spectra of compounds 3(Sm) and 4(Eu)display strong characteristic emissions of rare earth ions based on f-f transitions.Meanwhile,compound4(Eu) has a longer fluorescence lifetime up to 566.74 μs.Notably,co mpounds 3(Sm) and 4(Eu) exhibit the switchable luminescence behavior induced by photochromism,which allows them to be used as potential molecular switches.

关键词： Inorganic-organic hybrid Keggin-type polyoxometalates Rare earths Photochromism Photoluminescence

Irrigation and nitrogen fertiliser optimisation in protected vegetable fields of northern China:Achieving environmental and agronomic sustainability

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Journal of Integrative Agriculture 2024年第3期23卷 1022-1033页

作者： Bingqian Fan Yitao zhang Owen Fenton Karen Daly Jungai Li Hongyuan Wang Limei Zhai Xiaosheng Luo Qiuliang Lei shuxia Wu Hongbin Liu State Key Laboratory of Efficient Utilization of Arid and Semi-arid Arable Land in Northern China/Key Laboratory of Nonpoint Source Pollution Control Ministry of Agriculture and Rural Affairs/lnstitute of Agricultural Resources and Regional PlanningChinese Academy of Agricultural SciencesBeijing 100081China Institute of Geographic Sciences and Natural Resources Research Chinese Academy of SciencesBeijing 100101China Teagasc Environmental Research CentreWexford Y35Ireland Institute of Plant Nutrition Resources and Environmental SciencesHenan Academy of Agricultural SciencesZhengzhou 450002China

Globally,sub-optimal use of nitrogen (N) fertiliser and elevated N irrigation groundwater have led to high leached nitrate (NO_(3)^(–)) losses from protected vegetable field systems.Optimising fertiliser and irrigation management in different soil types is crucial to reduce future N loads from such systems.The present 4-year study examined leached N loads from lysimeter monitoring arrays set up across 18 protected vegetable system sites encompassing the dominant soil types of northern China.The treatments applied at each field site were:1) a high N and high irrigation input treatment (HNHI);2) a low N but high irrigation input treatment (LNHI) and 3) a low N with low irrigation input treatment (LNLI).Results showed that the mean annual leached total nitrogen loads from the HNHI,LNHI and LNLI treatments were 325,294 and 257 kg N ha^(–1) in the fluvo-aquic soil,114,100 and 78 kg N ha^(–1) in the cinnamon soil and 79,68 and 57 kg N ha^(–1) in the black soil,respectively.The N dissolved in irrigation water in the fluvo-aquic soil areas was 8.26-fold higher than in the cinnamon areas.A structural equation model showed that N fertiliser inputs and leaching water amounts explained 14.7 and 81.8%of the variation of leached N loads,respectively.Correspondingly,reducing irrigation water by 21.5%decreased leached N loads by 20.9%,while reducing manure N and chemical N inputs by 22 and 25%decreased leached N loads by only 9.5%. This study highlights that protected vegetable fields dominated by fluvo-aquic soil need management to curtail leached N losses in northern China.

关键词： agriculture water quality nitrate groundwater irrigation management

Synthesis of PtCu-based nanocatalysts:Fundamentals and emerging challenges in energy conversion

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Journal of Energy Chemistry 2022年第1期31卷 583-606,I0015页

作者： Wenjuan Yan Dongpei zhang Quanxing zhang Yu Sun shuxia zhang Feng Du Xin Jin State Key Laboratory of Heavy Oil Processing Center for Chemical Engineering Experimental TeachingChina University of PetroleumQingdao 266580ShandongChina

Proton exchange membrane fuel cell and direct methanol fuel cells have gained more attention due to high-energy density,remarkable conversion efficiency,and low emission.However,their widely practical application was hindered by the high usage,limited sources,and high price of Pt catalysts.To achieve more cost-effective catalytic systems,PtCu-based multi-metallic nanoparticles are highly efficient for the oxygen reduction reaction(ORR)and methanol oxidation reaction(MOR).The incorporation of non-noble Cu metal can alter the properties of hybrids by forming new facets,planes,edges to promote the cleavage or formation of chemical bonds in catalytic reaction.This is a rapid growing area with numerous contributions from the interdisciplinary areas of nanocatalysis.This paper has summarized the recent progress in the past two years,in synthesizing PtCu-based alloys with various composition and morphologies,and critically discussed the effect of the catalyst preparation method,metal precursor,surfactant,reductant and heating temperature on nanostructure and electronic configuration.The important role of the composition,size,and morphology of PtCu bimetallic catalysts for electro oxidation reactions has been further established for structure-dependency studies.The challenges and perspectives of nanocatalysts for ORR and MOR discussed in this work is to provide further insights into rational design for cost-effective materials for energy.

关键词： PtCu Nanostructure Electrocatalysis Oxidation

Cross-metathesis of biomass to olefins:Molecular catalysis bridging the gap between fossil and bio-energy

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Chinese Journal of Chemical Engineering 2022年第8期35卷 44-60页

作者： Wenjuan Yan Zhenchao You Kexin Meng Feng Du shuxia zhang Xin Jin State Key Laboratory of Heavy Oil Processing Center for Chemical Engineering Experimental TeachingChina University of PetroleumQingdao 266580China

Terminal olefins are important building blocks for the industry of biofuels,oligomers,and lubricants production.The industrial processes for production of olefins involving oligomerization of ethylene or cracking of petrochemical waxes have several flaws including low yield and high cost in product separation.Cross-metathesis of bio-derived unsaturated fatty esters and olefins with ethylene(ethenolysis),allows the conversion of sustainable waste biomass to various renewable olefins with much safer,less toxic,sustainable,and zero-CO_(2) emission processes.To our best knowledge,however,a comprehensive summary of key advances in this field(since 2017)is yet to be available,particularly on molecular features of homogeneous and heterogeneous catalysts.This paper presents a critical review on molecular structures of metal complex and oxide catalysts for ethenolysis of olefins and oleochemicals.The influence of cationic centers,coordination conditions,nature of ligands,operating conditions on catalyst performances will be systematically discussed along with relevant reaction mechanism.The key challenges for rational design of coordinated cationic hybrids have been summarized,which will provide insights to technological advancement of large-scale production of oleochemical-derived olefins.

关键词： Metathesis Catalysts Metal complex Metal oxide Olefins Oleochemicals

Lipocalin 2 in the Paraventricular Thalamic Nucleus Contributes to DSS-Induced Depressive-Like Behaviors

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神经科学通报:英文版 2023年第8期39卷 1263-1277页

作者： Yeru Chen Du Zheng Hongwei Wang shuxia zhang Youfa Zhou Xinlong Ke Gang Chen Department of Anesthesiology Sir Run Run Shaw HospitalSchool of MedicineZhejiang UniversityHangzhou 310016China

The incidence rate of anxiety and depression is significantly higher in patients with inflammatory bowel diseases(IBD)than in the general population.The mechanisms underlying dextran sulfate sodium(DSS)-induced depressive-like behaviors are still unclear.We clarified that IBD mice induced by repeated administration of DSS presented depressive-like behaviors.The paraventricular thalamic nucleus(PVT)was regarded as the activated brain region by the number of c-fos-labeled neurons.RNA-sequencing analysis showed that lipocalin 2(Lcn2)was upregulated in the PVT of mice with DSS-induced depressive behaviors.Upregulating Lcn2 from neuronal activity induced dendritic spine loss and the secreted protein induced chemokine expression and subsequently contributed to microglial activation leading to blood-brain barrier permeability.Moreover,Lcn2 silencing in the PVT alleviated the DSS-induced depressive-like behaviors.The present study demonstrated that elevated Lcn2 in the PVT is a critical factor for DSS-induced depressive behaviors.

关键词： Infammatory bowel disease Depression Lcn2 Blood-brain barrier

Medical Image Encryption Based on Josephus Traversing and Hyperchaotic Lorenz System

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Journal of Shanghai Jiaotong university(Science) 2024年第1期29卷 91-108页

作者：杨娜张淑霞白牡丹李珊珊 School of Information Engineering Chang'an UniversityXi'an 710064China

This study proposes a new medical image encryption scheme based on Josephus traversing and hyper-chaotic Lorenz system.First,a chaotic sequence is generated through hyperchaotic system.This hyperchaotic sequence is used in the scrambling and diffusion stages of the algorithm.Second,in the scrambling process,the image is initially confused by Josephus scrambling,and then the image is further confused by Arnold map.Finally,generated hyperchaos sequence and exclusive OR operation is used for the image to carry on the positive and reverse diffusion to change the pixel value of the image and further hide the effective information of the image.In addition,the information of the plaintext image is used to generate keys used in the algorithm,which increases the ability of resisting plaintext attack.Experimental results and security analysis show that the scheme can effectively hide plaintext image information according to the characteristics of medical images,and is resistant to common types of attacks.In addition,this scheme performs well in the experiments of robustness,which shows that the scheme can solve the problem of image damage in telemedicine.It has a positive significance for the future research.

关键词： medical image image encryption Josephus traversing hyperchaotic Lorenz system

PtCo-based nanocatalyst for oxygen reduction reaction:Recent highlights on synthesis strategy and catalytic mechanism

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Chinese Journal of Chemical Engineering 2023年第1期53卷 101-123页

作者： Wenjuan Yan Puhua Sun Chen Luo Xingfan Xia Zhifei Liu Yuming Zhao shuxia zhang Liang Sun Feng Du State Key Laboratory of Heavy Oil Processing Center for Chemical Engineering Experimental TeachingOil Industry Training CenterChina University of PetroleumQingdao 266580China Petrochemical Research Institute PetroChinaBeijing 102200China

Oxygen reduction reaction over Pt-based catalyst is one of the most significant cathode reactions in fuel cells.However,low reserves and high price of Pt have motivated researchers worldwide seeking enhanced utilization efficiency and durability by doping non-noble metals to form Pt-based alloy catalysts.Alloying Pt with Co has been recognized as one of the most effective approaches to achieve this goal.PtCo bimetal combination is one of the most promising candidates to synthesize highly efficient catalysts for oxygen reduction reaction(ORR)applications,owing to its relatively more suitable oxygen binding energy for four-electron transfer reactions.Recently,impressive strategies have been developed to fabricate more active and stable PtCo-based multimetallic alloys with tailorable size and morphology.This paper aims to summarize the most recent highlights on the study of the relationship between preparation strategies,morphologies,electroactivities of the PtCo-based catalyst at atomic level and further the relevant reaction mechanism.The challenges and opportunities on the further development of electrocatalysts for fuel cells are included to provide reference for the practical application.

关键词： Electrochemistry Catalysis Oxygen reduction reaction Fuel cells PtCo nanoalloy Multimetallic

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基于集成重要性采样的随机梯度下降算法

南京理工大学学报 2024年第3期48卷 342-350页

作者：张浩鲁淑霞河北大学数学与信息科学学院河北保定071002 河北省机器学习与计算智能重点实验室河北保定071002

许多机器学习和深度学习问题都可以使用随机梯度优化算法求解,目前流行的算法大多通过均匀采样从样本集中抽取样本计算梯度估计。然而,随机采样的梯度估计会带来较大的方差,这个方差会随着优化的进行而累积,降低算法收敛速度。为缓解这... 详细信息

许多机器学习和深度学习问题都可以使用随机梯度优化算法求解,目前流行的算法大多通过均匀采样从样本集中抽取样本计算梯度估计。然而,随机采样的梯度估计会带来较大的方差,这个方差会随着优化的进行而累积,降低算法收敛速度。为缓解这一现象,可以为每个样本赋予不同的采样概率。该文基于集成学习的思想,提出了一种新的选取非均匀采样分布的算法。算法的主要目的是选取一个采样器权重,使梯度估计的方差尽可能小。所提算法由多个简单采样器组成,采样权重为每个简单采样器分配贡献权重,从而得到最终的采样分布。集成重要性采样算法可以和以往的随机梯度优化方法任意结合,该文给出了使用集成重要性采样的随机梯度下降算法。在试验中,可以直观地看到算法起效的原因。在真实数据集中,展示了所提算法减小方差的效果,与其他算法相比具有一定优势。

关键词：集成学习重要性采样采样器随机梯度下降方差减少

Highly dispersed metal incorporated hexagonal mesoporous silicates for catalytic cyclohexanone oxidation to adipic acid

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Chinese Journal of Chemical Engineering 2020年第10期28卷 2542-2548页

作者： Wenjuan Yan Wenxiang zhang Qi Xia Shuaishuai Wang shuxia zhang Jian Shen Xin Jin State Key Laboratory of Heavy Oil Processing Center for Chemical Engineering Experimental TeachingChina University of PetroleumQingdao 266580China College of Environment and Resources Xiangtan UniversityXiangtan 411105China

Adipic acid is a dicarboxylic acid of great industrial importance,mainly used in the production of nylon-6,6 and polyurethane.The use of nitric acid as an oxidant in the industrial production of adipic acid poses significant carbon footprint to the environment.Clean adipic acid synthesis methods using a heterogeneous catalyst with H2O2 as oxidant and water as solvent have potential advantages of low catalyst cost,easy synthesis and recovery,cleanness and environmental protection.In this work,hexagonal mesoporous silicate materials were synthesized by a sol–gel method and evaluated for cyclohexanol/cyclohexanone oxidation to adipic acid.The physical and chemical properties of Fe-HMS were characterized by XRD,HR-TEM,BET and UV–Vis.The experimental results showed that Fe-HMS materials show pore sizes ranging from 2–3 nm.W-and Mo-based polyoxometalates were also evaluated and compared to the Fe-based HMS catalysts.To improve the adipic acid yield,the influence of the transition metal as well as the effect of metal loading,reaction temperature and catalyst amount on the catalytic performances of Fe-HMS have been investigated in details.When Si/Fe atomic ratio=100,Fe-HMS catalyst shows the highest activity,with a cyclohexanone conversion of 92.3%and adipic acid selectivity of 29.4%.The reaction pathway of cyclohexanone oxidation was further proposed based on experimental data.

关键词： Oxidation Adipic acid Hexagonal mesoporous silicates hydrogen peroxide