Unraveling the Interfacial Charge Migration Pathway at the Atomic Level in a Highly Efficient Z‐Scheme Photocatalyst

A highly efficient Z‐scheme photocatalytic system constructed with 1D CdS and 2D CoS₂ exhibited high photocatalytic hydrogen‐evolution activity of 5.54 mmol h^?1 g^?1 with an apparent quantum efficiency of 10.2 % at 420 nm. More importantly, its interfacial charge migration pathway was unraveled: The electrons are efficiently transferred from CdS to CoS₂ through a transition atomic layer connected by Co–S_5.8 coordination, thus resulting in more photogenerated carriers participating in surface reactions. Furthermore, the charge‐trapping and charge‐transfer processes were investigated by transient absorption spectroscopy, which gave an estimated charge‐separation yield of approximately 91.5 % and a charge‐separated‐state lifetime of approximately (5.2±0.5) ns in CdS/CoS₂. This study elucidates the key role of interfacial atomic layers in heterojunctions and will facilitate the development of more efficient Z‐scheme photocatalytic systems.     

全光纤多模速度干涉仪的研究

针对传统全光纤单模速度干涉仪在爆炸冲击试验中,前端的单模准直器对高速运动的物体的漫反射光难以有效收集,提出了全光纤多模速度干涉仪的装置。利用超辐射发光二极管作为光源,初步验证了全光纤多模速度干涉仪的可行性。主要阐述了全光纤多模速度干涉仪的原理和结构,并将其与全光纤单模速度干涉仪在喇叭振动速度的实验中进行比较,取得了一致的结果,最后还进行霍普金森压杆撞击实验,实测的速度最大值为10.49 m/s,与理论值10 m/s符合较好。     

基于载流子选择性接触的N型晶硅电池钝化特性研究

为了研究载流子选择性接触结构在N型晶硅电池钝化特性,本文设计了专门的材料结构.分析对比了不同掺杂浓度分布的材料结构在退火后、沉积SiNx:H薄膜后及烧结后隐开路电压值的变化,并对其钝化机理进行了分析.研究结果表明隐开路电压值对掺杂浓度分布非常敏感.随着掺杂浓度分布进入硅基体的"穿透"深度增加,相对应地退火后、SiNx:H薄膜沉积后及烧结后隐开路电压值均呈现先增加后减小的趋势,且样片沉积SiNx:H薄膜后隐开路电压的增加幅度也逐渐减小,而样片烧结后隐开路电压值又出现不同幅度的下降,且隐开路电压值的下降幅度逐渐减小.通过适当的掺杂工艺,可以使得烧结后的隐开路电压均值达到738 mV.     

聚甲基丙烯酸甲酯-氯化银复合纳米微球的制备及其摩擦学性能

采用原位种子乳液聚合法合成了聚甲基丙烯酸甲酯 氯化银(PMMA AgCl)核壳结构复合纳米微球,通过透射电镜(TEM),红外光谱(IR),热分析(TG DTA)和X射线粉末衍射(XRD)等测试手段对其结构及性能进行了表征.在四球试验机上对其摩擦学行为进行了考察,研究结果表明,PMMA AgCl核壳结构复合纳米微球用作润滑油添加剂具有良好的抗磨性能,能显著提高基础油的失效负荷.     

Conversion of Cellulose and Lignin Residues into Transparent UV-Blocking Composite Films

The valorization of cellulose and lignin residues in an integrated biorefinery is of great significance to improve the overall economics but has been challenged by their structural recalcitrance, especially for lignin residue. In this work, a facile chemical conversion route to fabricating functional UV-blocking cellulose/lignin composite films through a facile dissolution–regeneration process using these biomass residues was proposed. Three representative lignin residues, i.e., aspen and poplar wood lignin, and corn stover (CS) lignin were assessed for their feasibility for the film fabrication. The UV-blocking performance of the composite films were comparatively investigated. Results showed that all these three lignin residues could enhance the UV-blocking property of the composite films, corresponding to the reduction in the optical energy band gap from 4.31 to 3.72 eV, while poplar lignin had a considerable content of chromophores and showed the best UV-blocking enhancement among these three assessing lignins. The enhancement of UV-blocking property was achieved without compromising the visible-light transparency, mechanical strength and thermal stability of the composite films even at 4% lignin loading. This work showed the high promise of integrating biomass residue conversion into lignocellulose biorefinery for a multi-production purpose.     

Fabrication and sustained release properties of porous hollow silica nanoparticles

MCM-41-type mesoporous silica nanospheres(MSN) have been prepared using n-cetyltrimethylammonium bromide(CTAB) as a soft template.The pseudo-moire' rotational pattern inside the MSN results in many interior defects.Hollow mesoporous silica(HMS) spheres were synthesized by solvent extraction of the template from MSN.The morphology and structure of MSN and HMS were studied by TEM,XRD and nitrogen sorption techniques.A model drug,bromocresol green dye,was packed inside different regions of HMS through impregna...     

用离子液前驱体合成高荧光性能的ZnO和CdS纳米材料

合成了含Cd和Zn的离子液,使其提供金属离子,与Na2S反应制备离子液包裹的半导体纳米材料．X射线衍射和透射电子显微镜分析结果显示：在Cd离子液与Na2S反应中,得到的是尺寸在5～6nm、离子液包裹CdS纳米晶,而在Zn的体系中,最终产物为尺寸在1μm左右六方盘形貌的ZnO颗粒．用热力学和结晶动力学详细讨论了造成Cd和Zn体系在反应条件相同时,产物的形貌和结构差别的原因．荧光性质的测试结果表明：该方法制备的ZnO和CdS纳米粒子具有很好的荧光性能．     

Shape-controlled solvothermal synthesis of bismuth subcarbonate nanomaterials

Much effort has been devoted to the synthesis of novel nanostructured materials because of their unique properties and potential applications. Bismuth subcarbonate ((BiO)₂CO₃) is one of commonly used antibacterial agents against Helicobacter pylori (H. pylori). Different (BiO)₂CO₃ nanostructures such as cube-like nanoparticles, nanobars and nanoplates, were fabricated from bismuth nitrate via a simple solvothermal method. The nanostructures were characterized by powder X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM). It was found that the solvents and precursors have an influence on the morphologies of (BiO)₂CO₃ nanostructures. The possible formation mechanism of different (BiO)₂CO₃ nanostructures fabricated under different conditions was also discussed.     

Synthesis and antitumor evaluation of C3/C3 fluoroquinolone dimers(Ⅰ):Tethered with a fused heterocyclic s-triazolo[2,1-b][1,3,4]thiadiazole

<正>Five C3/C3 fluoroquinolone dimers tethered with a fused heterocyclic ring of s-triazolo[2,1-b][1,3,4]thiadiazole derived from antibacterial quinoiones were synthesized and characterized,and their in vitro antitumor activity against L1210,CHO cell lines was evaluated via the respective IC_(50) values.     

Electrochemical impedance analysis of nanoporous TiO_2 electrode at low bias potential

<正>TiO_2 colloid was prepared by the sol-gel method and was bladed on transparent conduction glass to made nanoporous electrode. The impedance performance of TiO_2 electrode was studied at various bias potential.A simplified equivalent circuit was proposed to investigate the charge transport impedance of TiO_2 film and good fitting results were obtained.