Effects of PNN/PZT ratios on phase structure,electric properties and relaxation behavior of PZN–PNN–PZT ceramics

Pb(Zn_1/3Ni_2/3)_c(Ni_1/3Nb_2/3)_a(Zr_xTi_y)_bO₃ (PZN–PNN–PZT, the ratios of PNN/PZT a/b were 0.88, 1 and 1.136) piezoelectric ceramics were prepared by a traditional solid-state reaction method. The effects of PNN/PZT ratio on phase structure, microstructure and electric properties as well as the relaxation behaviors of PZN–PNN–PZT ceramics were investigated. The XRD patterns showed that all ceramics samples had a pure perovskite phase structure. Meanwhile, it was found that the phase structure undergoes a tetragonal, tetragonal-rhombohedral to rhombohedral transition as ratios of PNN/PZT increased. With the increasing of a/b from 0.88 to 1.136, the dielectric constant and diffusive phase coefficient decreases, it was indicated that relaxation behaviors also decreased. When ceramics with a/b was 1.136, the dielectric relaxation γ reached the minimum and electrical properties were poor. The electric properties of ceramics with a/b was 1.00 have an excellent properties, it was indicated that ceramics reached an optimization at the MPB structure.     

Effect of bioactive dental adhesive on periodontal and endodontic pathogens

The objectives of this study were to: (1) develop a new bioactive dental bonding agent with nanoparticles of amorphous calcium phosphate and dimethylaminohexadecyl methacrylate for tooth root caries restorations and endodontic applications, and (2) investigate biofilm inhibition by the bioactive bonding agent against eight species of periodontal and endodontic pathogens for the first time. Bonding agent was formulated with 5?% of dimethylaminohexadecyl methacrylate. Nanoparticles of amorphous calcium phosphate at 30?wt% was mixed into adhesive. Eight species of biofilms were grown on resins: Porphyromonas gingivalis, Prevotella intermedia, Prevotella nigrescens, Aggregatibacter actinomycetemcomitans, Fusobacterium nucleatum, Parvimonas micra, Enterococcus faecalis, Enterococcus faecium. Colony-forming units, live/dead assay, biomass, metabolic activity and polysaccharide of biofilms were determined. The results showed that adding dimethylaminohexadecyl methacrylate and nanoparticles of amorphous calcium phosphate into bonding agent did not decrease dentin bond strength (P?>?0.1). Adding dimethylaminohexadecyl methacrylate reduced the colony-forming units of all eight species of biofilms by nearly three orders of magnitude. The killing efficacy of dimethylaminohexadecyl methacrylate resin was: P. gingivalis?>?A. actinomycetemcomitans?>?P. intermedia?>?P. nigrescens?>?F. nucleatum?>?P. micra?>?E. faecalis?>?E. faecium. Dimethylaminohexadecyl methacrylate resin had much less biomass, metabolic activity and polysaccharide of biofilms than those without dimethylaminohexadecyl methacrylate (P?<?0.05). In conclusion, a novel dental adhesive was developed for root caries and endodontic applications, showing potent inhibition of biofilms of eight species of periodontal and endodontic pathogens, and reducing colony-forming units by three orders of magnitude. The bioactive adhesive is promising for tooth root restorations to provide subgingival margins with anti-periodontal pathogen capabilities, and for endodontic sealer applications to combat endodontic biofilms.     

Ag<Subscript>2</Subscript>S/Bi<Subscript>2</Subscript>S<Subscript>3</Subscript> co-sensitized TiO<Subscript>2</Subscript> nanorod arrays prepared on conductive glass as a photoanode for solar cells

TiO₂ nanorod arrays (TiO₂ NRAs) were synthesized through a hydrothermal method. Ag₂S and Bi₂S₃ were then grown on the surface of TiO₂ NRAs with successive ionic layer adsorption and reaction method. The pristine rutile TiO₂ NRAs, Ag₂S/TiO₂, Bi₂S₃/TiO₂, and Bi₂S₃/Ag₂S/TiO₂ electrodes were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, ultraviolet–visible absorption spectroscopy, and electrochemical analysis. According to photoelectrochemical (PEC) measurement, an enhanced short circuit current density was obtained for the co-sensitized TiO₂ NRAs under simulated sunlight illumination, which was 10.7 times higher than that of the TiO₂ NRAs. Appropriate potential positions of conduction band and valence band of Bi₂S₃ that match well those of rutile TiO₂ NARs and Ag₂S lead to the improved PEC performance. In addition, the PEC property of the co-sensitized TiO₂ NRAs under visible light irradiation was also investigated and showed a dramatically enhanced photocurrent response.     

Whisker growth on SnAgCu–xPr solders in electronic packaging

The addition of rare earth Pr into Sn3.8Ag0.7Cu solder results in the formation of PrSn₃ phase, which can induce the whiskers growth. After several hours’ exposure at room temperature in air, different morphologies of whiskers appear in the regions of PrSn₃ intermetallic compounds. The Pr content and storage time are the main parameters for affecting the whiskers growth at ambient temperature. The oxidation mechanism of PrSn₃ phase was used to explain the whiskers growth, the compressive stress is proposed as the driving force for whisker growth.     

聚(3-羟基丁酸酯-3-羟基戊酸酯)/聚碳酸亚丙酯复合支架的构建与表征

分别采用反应性和非反应性熔融共混方法结合粒子沥滤技术以及碱处理技术构建不同质量比的聚(3-羟基丁酸酯-3-羟基戊酸酯)(PHBV)/聚碳酸亚丙酯(PPC)复合支架,通过表征支架的表面形态、孔隙率大小和体外降解性能,发现反应性共混法可显著改善支架的相容性和界面粘接。非反应性熔融共混法构建的支架孔隙率高于反应性共混法构建的复合支架。随着PPC含量的升高,复合支架的孔隙率升高。当PHBV/PPC质量比达50/50时,支架在PBS缓冲液中降解最快,反应性共混法构建的支架亲水性高于非反应性共混法,碱处理技术可显著改善复合支架的亲水性。这对功能重建的体内研究和临床实践具有潜在的理论价值和应用前景。     

数字化背景下汽车仪表盘界面设计研究

目的研究汽车数字化仪表盘界面因素对驾驶员驾驶体验的作用和影响。方法分析现有汽车仪表盘的研究现状和问题,选取5个具有代表性的样本,从仪表盘样式、整体布局、信息架构、基本信息列表4个方面,同时搭配色彩比例、风格类型进行纵向与横向分析研究。结论通过对选取的5个样本的研究和分析,提出在数字化汽车仪表盘的设计过程中,遵循布局简洁、色彩准确、体验丰富的设计规律,具有重要的实践意义和价值。     

会展设计中的交互技术应用分析

目的研究交互技术在会展设计中的应用。方法通过对世博会经典展馆与专业会展设计的分析,对交互技术与会展设计之间的关系与应用方式进行研究,并以此对会展设计与交互技术应用的趋势作出展望。结论在以世博会为代表的会展活动与设计中,交互与虚拟现实技术的应用改变了传统的展示方式,不但强调和突显了观众的主体作用,而且也扩大了信息的承载量,提高了展示的艺术效果与效率。     

第三组元对Mg-Sn合金铸态组织与力学性能的影响

利用光学显微镜、扫描电子显微镜和X射线衍射仪分析Mg-3.52Sn-xM和Mg-6.54Sn-xM(M=Al,Zn,Nd,Gd)合金的铸态组织和相组成,测试其拉伸力学性能。结果表明:在Mg-3.52Sn合金中分别添加0.91%(质量分数,下同)Al和1.03%Zn后,粗大树枝晶有所细化,小块状Mg2Sn相极少;分别添加0.92%Nd和1.10%Gd后,树枝晶明显弱化,出现较多的小块状或细短杆状化合物Mg-Sn-Nd和Mg-Sn-Gd。在Mg-6.54Sn合金分别添加0.93%Al和1.08%Zn后,树枝晶明显细化,原先趋于连续网状分布的Mg2Sn相有所破碎;分别添加0.86%Nd和0.74%Gd后,树枝晶亦明显弱化,Mg2Sn相已完全破碎成小块状并呈弥散分布或出现明显破碎,同样出现较多的小块状或细短杆状化合物Mg-SnNd和Mg-Sn-Gd。在Mg-3.52Sn和Mg-6.54Sn二元合金中添加约1%的Al和Zn能有效提高其室温和高温拉伸力学性能,而分别添加约1%的Nd和Gd则不能有效提高其室温和高温拉伸力学性能,且Nd的弱化效果更明显。     

含季铵盐聚合物丙烯酸酯共混防污涂料的制备与性能

用溶液聚合法合成了甲基丙烯酰乙基三甲基氯化铵(DMC)-甲基丙烯酸缩水甘油醚(GMA)-丙烯酸乙酯含季铵盐聚合物(QASP)的丙烯酸酯共聚物,并将合成的含季铵盐的丙烯酸酯共聚物和气相二氧化硅触变剂、氧化亚铜防污剂碾磨混合均匀得到共混物防污涂料。测试结果表明:随着共混物涂料中DMC用量的增加,涂层的抗拉强度先增加后降低,剪切强度降低,亲水性增强,有利于阻抗蛋白质的吸附;涂层吸水率的温敏性较强;防污涂料中铜离子渗出率在达到峰值后还能保持在比较高的水平,对于防污有效。