十六胺有机膜对羟基磷灰石晶体生长与形貌调控

采用X射线XRD、红外光谱FTIR、扫描电镜SEM、透射电镜TEM等分析手段,研究了十六胺有机膜对羟基磷灰石(HA)晶体结构、形核、晶体形貌和结晶学定向生长的调控作用及其机理。结果表明:无有机膜时,生成物为磷酸八钙(OCP)和羟基磷灰石(HA)的混合物,其生长速率很慢且晶体排列无一定规则;而在十六胺有机膜调控下,生成物为按规则排列、沿〈0001〉定向生长、结晶良好的纳米片状羟基磷灰石晶体,且其形核和生长速度均很快。其原因是:十六胺有机膜上带有的大量极性强、电荷密度高的—NH_3基团,通过静电作用在有机膜/溶液界面处形成局域过饱和浓度,促进羟基磷灰石晶体形核;另一方面,十六胺有机膜的二维晶格尺寸与HA(0001)面的晶格参数具有良好的匹配关系,构造了一个有利于HA以(0001)面形核生长的结构框架,从而促进了HA相沿〈O001〉方向定向生长。     

聚乙烯吡咯烷酮对纳米羟基磷灰石形貌的影响及其机理分析

以Ca(NO3)2.4H2O,(NH4)2HPO4为反应物,聚乙烯吡咯烷酮(PVP)为添加剂,在水热条件下,成功制得了椭球状(长径比1-1.5)的纳米羟基磷灰石(HA)。采用X射线衍射(XRD)、傅里叶变换红外吸收光谱(FTIR)和透射电子显微镜(TEM)等测试手段对所制得的纳米HA进行表征,结果表明PVP能较大程度地影响纳米HA的形貌。纳米HA颗粒的长径比随着PVP浓度的增加而减小,当PVP浓度为1.0%(质量分数)时,纳米HA长径比达最小值(1.5左右)。PVP对纳米HA形貌的调控机制可能是Ca2+与PVP形成配位键和PVP在纳米HA上吸附2种机理协同作用的结果。     

低Ca/P比溶液电沉积羟基磷灰石涂层

电沉积羟基磷灰石涂层具有工艺简单、过程易控制、适于在复杂表面制备厚度均匀涂层的特点.沉积液的Ca/P比直接影响涂层中的物相组成与涂层形貌.作者采用电沉积与后续热处理相结合的工艺,用低Ca/P比溶液在金属钛表面沉积羟基磷灰石(HA)涂层.利用X射线衍射仪、透射电镜和扫描电镜分析涂层中物相组成及后续热处理对涂层中物相和涂层形貌的影响.结果表明:随电压与温度的升高,涂层中羟基磷灰石含量增加;空气中500℃热处理后,涂层基本转化为羟基磷灰石,其Ca/P比约为1.61;热处理前,涂层由块状和条状物质组成;热处理后,涂层形貌并未改变,它由纳米颗粒的HA凝聚烧结而成.     

原位合成莫来石柱状晶强化羟基磷灰石材料

以羟基磷灰石(HA)为基体,经硅溶胶表面包覆处理的Al2(SO4)3(AES)为第二相,采用原位反应合成法制备自生莫来石柱状晶增强羟基磷灰石材料。研究莫来石晶体的形成过程以及复合材料的相组成、微观形貌和力学性能。结果表明,添加AES可以提高HA的抗弯强度,经1 050℃烧结、含10%AES的复合材料抗弯强度可达71.21 MPa,比基体提高185%;硅溶胶在加热过程中结晶化转变的顺序是:800℃以下为非晶态,800~950℃晶化成方石英,950～1 100℃为方石英+磷石英;Al2(SO4)3与SiO2反应原位生成柱状莫来石,柱状莫来石可起到类纤维的增强作用使材料强度提高。     

聚乳酸/羟基磷灰石复合型多孔状可降解生物材料

以乳酸和乙醇酸为原料分别合成了丙交酯(LA)和乙交酯(GA)2种单体,并用单体聚合成了聚丙交酯(PLA)和丙交酯乙交酯共聚物(PLGA),结合用粉末冶金的方法制得的纳米羟基磷灰石粉末(HA),制得了聚乳酸/羟基磷灰石复合型生物可降解的多孔材料。研究结果表明,PLA和PLGA聚合物的产率同聚合过程中的氮压有关,控制造孔剂的粒度,可以得到理想的多孔材料。     

水热法合成不同形貌羟基磷灰石

羟基磷灰石由于具有良好的生物相容性和生物活性而应用广泛,形貌控制对其应用至关重要。本文分别以Ca(NO3)2.4H2O、KH2PO4.3H2O为Ca源和P源,采用水热法制备不同形貌的羟基磷灰石。用X射线衍射(XRD)和扫描电镜(SEM)对反应产物进行表征,研究水热反应温度、水热反应时间和反应物浓度对羟基磷灰石形貌的影响。结果表明,不同条件下,产物为长径比不同的片状、带状及花状羟基磷灰石(HA),其长度为1~100μm、宽1~5μm、厚约100 nm、长径比为1~100,并从晶体生长动力学方面探讨不同合成条件对羟基磷灰石形貌的影响机理。     

乙二胺四乙酸二钠对钛合金表面羟基磷灰石涂层的影响

采用水热电化学方法在Ti6Al4V基体表面沉积羟基磷灰石(HA)涂层,研究乙二胺四乙酸二钠(EDTA-2Na)对HA涂层的物相组成、形貌、结合强度及生物相容性的影响.结果表明,电解液中无论添加EDTA-2Na与否,水热电化学沉积得到的仍为结晶度较高、生物相容性较好的HA涂层;不同的是,与不添加EDTA-2Na的涂层相比,添加EDTA-2Na后沉积得到的HA晶体形貌发生较大改变.随着EDTA-2Na浓度的增加,HA晶体从长薄片状到花瓣状以及纤维带状;HA涂层(002)晶面衍射峰强度随着EDTA-2Na浓度的增加逐渐减弱,涂层厚度也随之减小;HA涂层与基体的结合强度,随EDTA-2Na浓度的增加先增大后减小,在浓度为7.5×10~(-4)mol·L~(-1)时达到最大值16.8 MPa.     

黑磷烯尺寸对黑磷烯/羟基磷灰石混合物气敏性能的影响

采用水热法制备短棒状羟基磷灰石(HA),通过液相剥离法制备黑磷烯(black phosphorene,BP),并采用不同的离心速率分离出具有不同尺寸的BP。制备BP质量分数为7.0%的BP/HA混合物,用X射线衍射仪、扫描电镜、透射电镜、原子力显微镜和拉曼光谱对混合物的物相组成、微观形貌和结构进行表征,同时使用气体传感系统研究纯HA以及含有不同尺寸BP的BP/HA混合物的气体传感特性。结果表明,加入BP可显著提高HA对氨气的响应,BP的尺寸越小,对HA气敏性能的提升越大。其中BP-10000/HA对浓度(气敏实验所用空气中氨气的体积分数)为100×10^-6的氨气的响应高达58.7%,当氨气浓度上升到1 000×10^-6后,响应高达98.3%。BP尺寸越小,气敏性能越好,可能是由于具有更大的比表面积,因而具备更多的活性位点。总之,BP可显著提升HA的气敏性能,BP/HA混合物是一种很有前途的室温气敏材料。     

柠檬酸对Ca(NO3)2-P2O5体系合成羟基磷灰石粉体的影响

采用Ca(NO3)2·4H2O和P2O5为主要原料,柠檬酸为螯合剂,利用溶胶-凝胶法合成了纳米羟基磷灰石粉体.通过DSC,XRD和SEM等手段,分析了纳米HA粉体的形成历程,系统地研究了柠檬酸对粉体形成过程、产物杂质相及粉体粒度的影响,并对其影响机理进行了初步探讨.结果表明:柠檬酸的加入提高了胶体的稳定性,通过螯合作用改变了HA的形成历程.与不加柠檬酸的前驱体所制得的粉体相比,加柠檬酸后所得的HA粉体中杂质相CaO的含量明显降低.同时,柠檬酸的加入有效地抑制了粉体团聚,最终合成的粉体粒度小、颗粒均匀且具有良好的分散性.     

几种骨组织工程复合支架材料在模拟生理溶液中的生物矿化性能比较

采用生物活性玻璃(BG)、磷酸三钙(TCP)、羟基磷灰石(HA)等生物活性陶瓷与3-羟基丁酸酯-3-羟基戊酸酯的共聚物(PHBV)复合,制备了性能良好的骨组织工程支架材料,分析了PHBV/BG,PHBV/TCP,PHBV/HA三种复合多孔支架在模拟生理溶液中的一系列化学反应,以及多孔材料在模拟生理溶液中浸泡后的成分、结构和微观形貌的变化。研究结果表明,三种复合支架材料在模拟生理溶液中发生了降解反应而失重;PHBV/BG和PHBV/TCP在模拟生理溶液中还发生了生物矿化反应,在表面形成矿化沉积层,为具有骨生物活性的结晶态类骨碳酸羟基磷灰石;而PHBV/HA在模拟生理溶液中没有明显的生物活性反应。     

Dynamics of Gradient Bioceramic Composite Coating on Surface of Titanium Alloy by Wide-Band Laser Cladding

Hydroxyapatite (HA) ,akindofbioactivematerial,haswideapplicationprospectinhardtissuereplacementandrepairbecauseofsimilarchemicalcompositionandcrystallographicstructuretothoseofbonemineral[1,2 ] .TheHAcoatingwithbioactivityandbiocompatibilityonthesur faceo…     

Effect of Y2O3 Content on Microstructure of Gradient Bioceramic Composite Coating Produced by Wide-Band Laser Cladding

Hydroxyapatite (HA) ,a kind of bioactive materi-al , has wide application prospect in hard tissue re-placemen and repairment due to its si milar chemicalcomposition and crystallographic structure to that ofbone mineral[1 ,2]. Since HA has lowstrength (50 …     

熔盐电解法制备硅纳米线及其生长过程研究

结合熔盐电解法制备了数微米长、200nm左右宽的纳米级硅线。采用预烧结的多孔SiO2粉末为阴极、等摩尔比的CaCl2-NaCl混合熔盐为电解质、石墨棒为阳极,在700℃、1.8V槽电压下通电5h后获得产物单质Si。研究了单质Si在电化学形核及后续生长过程中的微观结构及形貌演变规律,发现在晶体Si电化学形核后逐渐堆积形成"珠串"状结构,构成了硅线的雏形,在高温作用下,该结构继续生长最终形成纳米级硅线结构。     

热处理对羟基磷灰石粉体表征的影响

采用化学沉淀+喷雾干燥法制备羟基磷灰石(HA)粉末,并对粉末分别采用三种不同方式的热处理:90℃下干燥24h、1200℃下烧结2h和火焰重熔,对获得的三种粉末进行TEM、SEM和XRD分析,结果表明火焰重熔热处理后的粉末结晶度最好,而且表面更加光滑致密,提高喷涂性能。     

Synthesis and Characterization of Er3+∶Y3Al5O12 Nanocrystalline Powders Prepared by Sol-Gel Method

Nano-sized Er3 ∶Y3Al5O12 powders was successfully prepared via a simple sol-gel route at as low a temperature at 800 ℃ whereas a temperature much higher is necessary to obtain this compound by solid state synthesis (about 1500 ℃). The phase purity, composition and microstructural features of the materials were analyzed by means of X-ray diffraction(XRD), infrared spectroscopy(IR) and transmission electron microscopy(TEM), and no other intermediate phase were observed to form in the range of 700～1000 ℃. The luminescence spectra of Er3 substituted for Y3 in YAG in 1% content was characterized on samples at different temperature.     

MgO/HA复合材料的强韧化与冷处理

以多种不同粒径的MgO颗粒为第二相,以HA为基体,采用无压烧结法制备MgO/HA复合材料;研究MgO粒径与MgO/HA复合材料的抗弯强度和断裂韧性之间的关系,探讨冷处理对复合材料性能的影响。结果表明:添加适宜粒径的MgO颗粒能够提高HA复合材料的抗弯强度和断裂韧性,其断裂韧性可达基体断裂韧性的1.5倍,抗弯强度可达基体抗弯强度的1.29倍,MgO颗粒增韧的粒径范围为15～35μm,增强的粒径范围为<25μm。冷处理可以进一步提高复合材料的强度和韧性,而且可以改变增韧和增强的MgO粒径范围,使增强与增韧粒径的重叠范围变宽。     

Origin and evolution of the 1918 "Spanish" influenza virus hemagglutinin gene

The "Spanish" influenza pandemic killed over 20 million people in 1918 and 1919, making it the worst infectious pandemic in history. Here, we report the complete sequence of the hemagglutinin (HA) gene of the 1918 virus. Influenza RNA for the analysis was isolated from a formalin-fixed, paraffin-embedded lung tissue sample prepared during the autopsy of a victim of the influenza pandemic in 1918. Influenza RNA was also isolated from lung tissue samples from two additional victims of the lethal 1918 influenza: one formalin-fixed, paraffin-embedded sample and one frozen sample obtained by in situ biopsy of the lung of a victim buried in permafrost since 1918. The complete coding sequence of the A/South Carolina/1/18 HA gene was obtained. The HA1 domain sequence was confirmed by using the two additional isolates (A/New York/1/18 and A/Brevig Mission/1/18). The sequences show little variation. Phylogenetic analyses suggest that the 1918 virus HA gene, although more closely related to avian strains than any other mammalian sequence, is mammalian and may have been adapting in humans before 1918.     

人工滑液在材料表面成膜的AFM图像分析

用原子力显微技术（AFM）观测复合人工滑液在材料表面形成的吸附膜的表面形貌图像,吸附膜上清晰地显示有大量的椭球形分子．该吸附膜的形成可能是复合人工滑液对人工关节材料润滑性能显著提高的一个重要因素．     

The cytogenetic study of established Syrian hamster cell lines. II. A comparative analysis of the karyotypes of cell lines HaK, CER and BHK-21 (C-13)

Hydroxyapatite (HA) coatings were prepared by three thermal spraying methods: flame spraying, high velocity oxygen fuel spraying and plasma spraying. The HA was then examined by Rietveld analysis using the General Structure Analysis Software package (GSAS) and the results compared with those for the precursor powder. A comparison between HA before and after spraying showed that all three spraying methods caused a distortion in the unit cell in the form of a unit cell a-axis length decrease and a c-axis increase. Overall unit cell volumes showed a difference between the three thermal methods, with flame spraying and high velocity oxygen fuel methods giving a unit cell volume increase and the air plasma spraying method showing a decrease, compared to the starting powders. The two different starting powders used each showed a high oxygen occupancy for the hydroxyl oxygen. When thermally sprayed, both powders gave a reduction in occupancy, which suggested carbonate substitution for the OH group, but this was subsequently removed when thermally processed. The spraying also formed oxyapatite, indicated both by spectral analysis showing a reduction in the hydroxyl peak and by the hydroxyl oxygen occupancy falling to a level below 0.5. Major differences between the three spraying methods could be seen in the distortion index calculations. The thermal spraying techniques gave an increase in the distortion index, but it was significantly higher for the plasma-sprayed coating.