Unraveling the condensation reactions of heterometallic {BiNb_4} moieties into hybrid Bi_xNb_y-oxo clusters with mass spectrometry

The most effective methodologies for the construction of polynuclear complexes usually take advantage of preorganized building blocks.Herein,we successfully developed a new versatile heterometallic{BiNb₄}moiety,which can be applied for the assembly of less explored organic-inorganic hybrid polyoxoniobates.Through controlled condensation reactions,three{BiNb₄}moieties can be assembled into a pair of isomeric Bi₃Nb₁₈clusters at different temperatures;whilst four{BiNb₄}moieties can be combined into two unique Bi₄Nb₁₆and Bi₄Nb₁₈tetramers in different solvents.Interestingly,we have used mass spectrometry to probe the above condensation reactions,which clearly confirmed a stepwise bottom-up assembly process by capturing the presence of bismuth subsalicylate precursors,salicylate coordinated intermediates,Nb incorporated{BiNb₄}moieties and the final Bi_xNb_y-oxo clusters,respectively.Moreover,the packing modes of the{BiNb₄}units induce different solution behaviors,and the{BiNb₄}units in Bi4Nb16can be recombined by post-synthetic recrystallization in acetonitrile to produce a new tetramer Bi₄Nb₁₈-R.Therefore,this work provides not only a useful{BiNb₄}building unit but also the mechanism for their condensation,both of which will promote the future development of metal-oxo clusters.     

A carbonyl-rich covalent organic framework as a high-performance cathode material for aqueous rechargeable zinc-ion batteries

Aqueous rechargeable zinc-ion batteries (ZIBs) provide high theoretical capacity, operational safety, low-cost and environmental friendliness for large-scale energy storage and wearable electronic devices, but their future development is plagued by low capacity and poor cycle life due to the lack of suitable cathode materials. In this work, a covalent organic framework (Tp-PTO-COF) with multiple carbonyl active sites is synthesized and successfully introduced in aqueous rechargeable ZIBs for the first time. Tp-PTO-COF delivers high specific capacities of 301.4 and 192.8 mA h g⁻¹ at current densities of 0.2 and 5 A g⁻¹, respectively, along with long-term durability and flat charge–discharge plateaus. The remarkable electrochemical performance is attributed to the abundance of nucleophilic carbonyl active sites, well defined porous structure and inherent chemical stability of Tp-PTO-COF. Moreover, the structural evolution and Zn²⁺ ion intercalation mechanism are discussed and revealed by the experimental analysis and density functional theory calculations. These results highlight a new avenue to develop organic cathode materials for high performance and sustainable aqueous rechargeable ZIBs.

A covalent organic framework (Tp-PTO-COF) with carbonyl active sites was proposed as a novel cathode material and successfully applied in aqueous rechargeable zinc-ion batteries (ZIBs).     

雾化辅助化学气相沉积法氧化镓薄膜生长研究

采用自主设计搭建的雾化辅助化学气相沉积系统设备,开展了Ga₂O₃薄膜制备及其特性研究工作。通过X射线衍射研究了沉积温度、系统沉积压差对Ga₂O₃薄膜结晶质量的影响。结果表明,Ga₂O₃在425~650 ℃温度区间存在物相转换关系。随着沉积温度从425 ℃升高至650 ℃,薄膜结晶分别由非晶态、纯α-Ga₂O₃结晶状态向α-Ga₂O₃、β-Ga₂O₃两相混合结晶状态改变。通过原子力显微镜表征探究了生长温度对Ga₂O₃薄膜表面形貌的影响,从475 ℃升高至650 ℃时,薄膜表面粗糙度由26.8 nm下降至24.8 nm。同时,高分辨X射线衍射仪测试表明475 ℃、5 Pa压差条件下的α-Ga₂O₃薄膜样品半峰全宽仅为190.8″,为高度结晶态的单晶α-Ga₂O₃薄膜材料。     

Environmental Behaviors and Biological Effects of Engineered Nanomaterials: Important Roles of Interfacial Interactions and Dissolved Organic Matter

With the fast development of nanotechnology,reactive engineered nanomaterials(ENMs)are increasingly discharged into the environment,where they interact with environmental components and organisms and thus pose potential risks.The interactions-derived formation of nano-environmental and nano-bio interfaces determines environmental behaviors and biological effects of ENMs,and ubiquitous dissolved organic matter(DOM)is bound to impact the interfacial interactions and the resulted environmental risks.Herein,we systematically investigated adsorptive interactions between ENMs and various DOM representatives,and thereby demonstrated the effects of DOM on the aqueous suspension/aggregation,mobility in porous media,adsorption of contaminants,transformation,and biological accumulation and toxicity of ENMs.Overall,we conclude that natural DOM can in general expand environmental distribution of ENMs while limit their toxicity to organisms.     

Recent advances of hydrogel network models for studies on mechanical behaviors

Acta Mechanica Sinica - Current constitutive theories face challenges when predicting the extremely large deformation and fracture of hydrogels, which calls for the demands to reveal the...     

Syntheses,Crystal Structures and Fluorescence Properties of Three Complexes Based on 2,2'-Quinoline-4,4'-dicarboxylic Ligands

Crystallography Reports - Three new coordination complexes, [Mn(L)(H2O)4⋅(H2O)3]2 (1), [Mg(L)(H2O)4⋅(H2O)3]2 (2), and [Cu(L)(phen)⋅(H2O)4]2 (3) (H2L =...     

Surface Modification of ZrO2–3Y2O3 with Highintensity Pulsed N2+ Ion Beams

Russian Physics Journal -     

层状化合物La0.26Bi0.74OOH光学性能的研究

构建非中心对称结构及研究材料的构效关系对于探索新型非线性光学晶体具有重要意义.La0.26Bi0.74OOH是一种具有PbFC1型结构的层状化合物,结晶在非中心对称的正交晶系空间群Pmm2,其主体结构由[La0.26Bi0.74O2]-层和H+阳离子组成.本文采用水热法合成了La0.26Bi0.74OOH晶体,并首次测试了该化合物的非线性光学性能.粉末倍频实验显示La0.26Bi0.74 OOH的倍频响应为KH2PO4的0.6倍.紫外-可见-近红外漫反射光谱表明该化合物的截止波长为335 nm.此外,第一性原理计算显示该化合物为直接带隙半导体,其内部的Bi-O和La-O基团对La0.26Bi0.74 OOH的非线性光学性能起主要作用.     

芳基溴化合物的合成

以对溴苄溴和芳醛为原料,采用相转移Wittig反应合成了3个芳基溴化合物。其结构经1H NMR,IR和元素分析表征。     

HMD-Net: A Vehicle Hazmat Marker Detection Benchmark

Vehicles carrying hazardous material (hazmat) are severe threats to the safety of highway transportation, and a model that can automatically recognize hazmat markers installed or attached on vehicles is essential for intelligent management systems. However, there is still no public dataset for benchmarking the task of hazmat marker detection. To this end, this paper releases a large-scale vehicle hazmat marker dataset named VisInt-VHM, which includes 10,000 images with a total of 20,023 hazmat markers captured under different environmental conditions from a real-world highway. Meanwhile, we provide an compact hazmat marker detection network named HMD-Net, which utilizes a revised lightweight backbone and is further compressed by channel pruning. As a consequence, the trained-model can be efficiently deployed on a resource-restricted edge device. Experimental results demonstrate that compared with some established methods such as YOLOv3, YOLOv4, their lightweight versions and popular lightweight models, HMD-Net can achieve a better trade-off between the detection accuracy and the inference speed.