Fabrication and Characterization of Nanopillar-Like HA Coating on Porous Ti6Al4V Scaffold by a Combination of Alkali–Acid-Heat and Hydrothermal Treatments

Porous titanium scaffold with suitable porous architecture exhibits enormous potentials for bone defect repairs. However,insufficient osteointegration and osteoinduction still remain to open as one of the major problems to achieve satisfactory therapeutic effect. To solve this problem, many studies have been carried out to improve the bioactivity of porous titanium scaff old by surface modifications. In this study, porous Ti6Al4V scaff olds were fabricated using additive manufacturing technique. Porous architectures were built up based on a diamond pore structure unit. Alkali–acid-heat(AH) treatment was applied to create a TiO_2 layer on the porous Ti6Al4V scaff old(AH-porous Ti6Al4V). Subsequently, a hydrothermal treatment was employed to enable the formation of HA coating with nanopillar-like morphology on the alkali–acid-heat-treated surface(HT/AH-porous Ti6Al4V). The effects of surface modifications on apatite-forming ability, protein adsorption,cell attachment, cell proliferation and osteogenic gene expression were studied using apatite-forming ability test, protein adsorption assay and in vitro cell culture assay. It was found that the HT/AH-porous Ti6Al4V exhibited the highest apatite formation ability and best affinity to fibronectin and vitronectin. In vitro studies indicated that the mesenchymal stem cells(MSCs) cultured on the HT/AH-porous Ti6Al4V presented improved adhesion and differentiation compared with the porous Ti6Al4V and AH-porous Ti6Al4V.     

溶液pH值对微纳米气泡减轻超滤膜污染影响研究

为有效解决膜过滤过程中由于膜污染加剧而导致分离效率下降的问题,提出引入微纳米气泡工艺,研究了pH值为3.0、6.0和10.0时微纳米气泡(MNBs)对超滤过程的影响,通过扫描电镜和聚焦离子束电子束双束显微镜分析了膜表面污染。实验结果表明pH值为3.0、6.0和10.0时鼓入MNBs后超滤归一化通量分别为0.96、1.19和1.14。pH值为3.0时鼓入MNBs对腐植酸(HA)截留率无明显增强,pH值为6.0和10.0时鼓入MNBs后截留率分别提高了12.7%和10.0%。超滤膜表面滤饼层厚度随pH值增大而减小,鼓入MNBs后滤饼层疏松多孔,有效减弱了归一化通量下降。     

Polymer brush coatings for combating marine biofouling

A variety of functional polymer brushes and coatings have been developed for combating marine biofouling and biocorrosion with much less environmental impact than traditional biocides. This review summarizes recent developments in marine antifouling polymer brushes and coatings that are tethered to material surfaces and do not actively release biocides. Polymer brush coatings have been designed to inhibit molecular fouling, microfouling and macrofouling through incorporation or inclusion of multiple functionalities. Hydrophilic polymers, such as poly(ethylene glycol), hydrogels, zwitterionic polymers and polysaccharides, resist attachment of marine organisms effectively due to extensive hydration. Fouling release polymer coatings, based on fluoropolymers and poly(dimethylsiloxane) elastomers, minimize adhesion between marine organisms and material surfaces, leading to easy removal of biofoulants. Polycationic coatings are effective in reducing marine biofouling partly because of their good bactericidal properties. Recent advances in controlled radical polymerization and click chemistry have also allowed better molecular design and engineering of multifunctional brush coatings for improved antifouling efficacies.     

Carbon nanotube–polyaniline composites

The last decade has seen a growing interest in hybrid electrically conducting nanocomposites. This article aims to provide a detailed overview of the present status of research in carbon nanotube–polyaniline (CNT/PANI) composites, from processing to structural and property evaluations. CNT/PANI are synthesized by electrochemical and chemical processing. When chemical methods are used, the main challenge is to obtain processable CNT/PANI in the emeraldine salt (ES) form composites. Stable dispersions of ES–CNT in organic media are prepared using the post doping method, inverse emulsion polymerization, or ex situ polymerizations. On the contrary, stable water dispersions of CNT/ES are prepared using hydrophilization of a preformed CNT/ES composite, direct synthesis of micelle–CNT hybrid templates, interfacial polymerization, covalent functionalization of CNT with a water soluble polymer, or using electrostatic interactions between two oppositely charged ES and CNT aqueous colloids. Moreover, the strategies for the synthesis of ternary CNT/PANI composites incorporating noble metal nanoparticles, metal oxide, or graphene sheets are also presented and analyzed in depth. Finally, we give a review of potential applications, including chemical sensors, capacitors, fuel cells and electronic devices.     

Electrophoretic deposition of hydroxyapatite nanostructured coatings with controlled porosity

Hydroxyapatite (HA) coatings with controlled porosity were prepared by electrophoretic deposition (EPD) method. Carbon black (CB) particles were used as the sacrificial template (porogen agent). Two component suspensions containing different concentrations of HA and CB particles were prepared in isopropanol. It was found that the finer and positively charged HA nanoparticles are heterocoagulated on the coarser and negatively charged CB particles to form CB–HA composite particles with net positive charge. The deposition rate from the suspensions with WR (C_CB/C_HA ratio) of 0.25 was faster than that of those with WR: 0.5 at initial times of EPD. However the situation was reversed at longer EPD times. It was also found that the amount of porosity in the coatings increases as the CB concentration in the suspension increases (15%, 24%, 31%, 43% for the coatings deposited from the suspensions with 20 g/L HA nanoparticles and 0, 5, 10 and 20 g/L CB particles, respectively).     

Examination of HA230 turbine transition duct

Abstract

The present paper reports the results of an examination of a service run transition duct from one of Siemens' industrial gas turbines and the correlation between the findings for this, and those from the studies undertaken on laboratory exposed Haynes alloy 230 material. The studies have shown that there are changes in the microstructure and hardness of the material that can be related to temperature and time of exposure, and the information gained can lead to estimations of the average component operating temperature. Metallographic studies revealed a high level of heterogeneity of the grains in this transition duct.     

不同组分的腐植酸复合肥在辣椒上的施用效应及其生理机制研究

采用盆栽试验方法,研究了不同组分的腐植酸复合肥对辣椒生长及其生理特性的影响,以筛选出适于辣椒生长的最佳肥料方案。试验结果表明,不同组分腐植酸复合肥处理与等养分无机复合肥及对照相比,产量均有显著提高,提高幅度分别为8.1％～23.5％和165.0％～195.1％。其中以HAzn增产效果最为显著。对辣椒生理活性的影响,也是以HAZn总体表现效果最佳,它可提高辣椒体内NR、SOD、POD的活性,促进叶绿素的合成代谢。此外,微量元素锌、铁之间存在着一定的拮抗作用,在一个施肥方案中,二者不宜同时施用。     

羟基磷灰石／TiO2生物活性复合涂层的研究进展

以钛及合金为基体、HA作涂层的复合材料作为植入物应用很普遍．HA涂层与钛及合金基体的结合强度较低，易出现界面剥落现象；锐钛矿型TiO2陶瓷具有较好的生物相容性，能有效地隔离植入体和生物机体，而且能提高涂层和界面的强度，故制备HA／TiO2生物复合涂层已成为国内外学者的研究热点之一。综述了HA／TiO2生物复合涂层的研究进展。     

纳米羟基磷灰石制备的实验研究

采用NaP作为分散剂,共沸蒸馏脱水来制备纳米羟基磷灰石（HA）颗粒.通过X射线衍射仪、透射电子显微镜（TEM）、和粒度分布仪等设备分别表征所制取的粉末的物相、形貌、粒度分布.主要观察NaP和共沸蒸馏方法的效果.实验结果表明,NaP作为分散剂有一定效果且在20%附近有一个最佳分散点,但是会降低羟基磷灰石（HA）粉体的热稳定性,并且,共沸蒸馏能够有效的防止团聚的发生.     

一种增强服务器高可用性的设计方法

首先简要介绍了HA(High Availability)的内容和工作原理,然后详细分析了HA的心跳数据格式和心跳流程,给出了一种增强服务器高可用性的设计方法,并在Unix操作系统Solaris上采用C 完成了HA模块开发.