两步电化学法制备羟基磷灰石/氧化铝复合生物涂层的研究

研究旨在开发一种可应用于医用金属表面生物学改性的复合生物陶瓷涂层。通过先阳极氧化、再电沉积的两步电化学方法成功制备了羟基磷灰石(hydroxyapatite,HA)／Al2O3复合生物涂层。利用扫描电子显微镜(SEM)研究了阳极氧化Al2O3(anodic aluminum oxide,AAO)膜的表面形貌与HA／Al2O3复合涂层的表面及截面形貌结构;用X射线衍射仪(XRD)、Fourier变换红外光谱仪(FT-IR)与能谱仪(EDS)表征了复合涂层的物相组成;用等离子原子发射光谱仪(ICP-AES)和粘接拉伸试验分别测定涂层在模拟体液(SBF)中的体外行为和浸渍后涂层间的结合强度,结果表明：所制备的HA含有少量碳酸根,在SBF中呈现优良的稳定性并能诱导新的磷灰石层的形成;HA底部嵌入AAO膜的孔洞中形成互锁界面,经模拟体液处理后两者之间结合强度为3．2MPa。     

固相离子交换法制备碳酸羟基磷灰石涂层的研究

通过涂覆-烧结法在氧化铝(Al2O3)基体上制备羟基磷灰石(HA)/氟羟基磷灰石(FHA)双层涂层,然后采用固相离子交换法在湿CO2气氛中对HA表层进行碳酸化处理。XRD、FTIR和SEM测试结果表明:FHA中间层能有效地抑制HA与Al2O3的反应,湿CO2气氛中的湿气有利于分解相的恢复,而碳酸根能进入到表面涂层结构内部,形成A型替代为主的碳酸羟基磷灰石(CHA)。所获得的双层涂层具有多孔粗糙的表面,但与Al2O3基体结合紧密。     

悬浮液粉体含量对电泳沉积羟基磷灰石涂层的影响

从不同羟基磷灰石(hydroxyapatite,HA)粉体含量的悬浮液中,在钛表面电泳沉积HA涂层.采用扫描电镜、X射线衍射表征涂层的微观形貌及物相组成,通过黏结-拉伸实验测定涂层与基底的结合强度.结果表明:提高悬浮液的HA粉体含量,有助于提高电泳沉积HA涂层的致密性,改善其烧结性能,提高烧结致密化程度;HA涂层致密性的提高,有效地抑制了钛基底表面氧化反应,改善了涂层与基底的界面结合状态,使HA涂层与钛基底的结合强度从悬浮液HA粉体含量为5g/L时的4.54MPa,提高到悬浮液HA粉体含量为20g/L时的19.92MPa.     

钛涂覆多孔羟基磷灰石/氧化铝生物陶瓷涂层的性能研究

通过电泳沉积的方法在生物医用钛基体表面制备羟基磷灰石(HA)/Al/壳聚糖(CS)复合涂层,通过高温烧结分解CS颗粒并制备钛基多孔HA/Al_2O_3复合生物陶瓷涂层。通过粘结-拉伸实验测定涂层与基材的结合强度;XRD和SEM对涂层的物相组成和形貌进行表征;CHI660C电化学工作站测试涂层在模拟体液中的耐蚀性能。研究表明,经过热处理后的涂层为表面可形成平均孔径为5μm的多孔HA/Al_2O_3,涂层厚度可达25μm,涂层中的HA颗粒致密粘连,Al在高温条件下反应成Al_2O_3从而使涂层与基体的结合强度最高可达30.5MPa,涂层的涂覆使Ti金属在人体模拟体液中具有良好的耐腐蚀能力。     

微弧氧化和电泳沉积复合制备羟基磷灰石/TiO2复合涂层及其生物学特性

采用微弧氧化和电泳沉积复合的方法,在钛样品表面沉积了羟基磷灰石(hydroxyapatite,HA)/TiO2复合涂层.用扫描电子显微镜,能量散射X射线能谱分析和X射线衍射对复合涂层的表面形貌、形成过程、元素组成及含量变化、相组成进行了观察和分析.通过剪切粘结实验确定了复合涂层与基体的结合强度,并在高温消毒后,将成骨样细胞MC-3T3-E1接种于试件表面进行培养以评估HA/TiO2复合涂层的生物学性能.结果表明形成的复合涂层由内层致密的TiO2层、中间HA/TiO2混合过渡层和外层HA层构成,其中HA含量呈梯度变化,使TiO2层逐渐向HA层过渡.HA/TiO2复合涂层和基体间的结合强度约为(19.3±2.5)MPa.通过细胞免疫荧光染色观察到细胞在培养3 h就可附着于复合涂层表面并形成良好的铺展,而且随着培养时间的延长,细胞的形态更加舒展,附着在复合涂层表面的细胞数量亦逐渐增加,初步表明复合涂层具有较好的生物学和力学性能.     

羟基磷灰石/TiO_2复合涂层在模拟脑脊液中生物相容性(英文)

应用阳极氧化法在Ti-6Al-4V钛合金(TC4)表面制备了多孔TiO2涂层,在TiO2涂层表面电沉积制备了羟基磷灰石(hydroxyapatite,HA)/TiO2复合涂层,用实验用人工脑脊液(artificial cerebrospinal fluid,ACSF)体液模拟人体的脑脊液,以TC4和TiO2涂层为对比,研究了HA/TiO2涂层在浸泡过程中发生的物理化学变化,考察了HA/TiO2复合涂层抑制钛合金中元素Al和V的析出情况。结果表明:3种样品随浸泡时间的延长遵循的生长规律为:HA成核→HA晶粒长大→HA晶粒相互团簇形成一体→涂层逐渐扩大覆盖到整个基体表面;TC4,TiO2以及HA/TiO2涂层在ACSF中都能够诱导HA的生成,表现出了良好的生物活性。检测浸泡后溶液中Al和V的浓度可知,阳极氧化法制备的TiO2涂层对于Al,V元素的析出起到了一定的抑制作用,能够进一步提高钛合金的生物相容性。     

溶胶凝胶法制备羟基磷灰石/TiO2复合生物活性涂层的研究

通过溶胶凝胶法在纯钛基体上制备了羟基磷灰石/TiO2复合生物活性涂层.HA可以提高钛基的生物活性,TiO2可以提高涂层与基体的物理、化学相容性和结合强度.HA和TiO2溶胶由前驱体制得,按不同物质的量比直接混合两种溶胶来制备复合溶胶.使用XRD、SEM研究了不同温度下热处理后涂层的组成和结构.实验结果表明HA的结晶度和晶粒随着温度的升高而提高和变大;涂层表面为连续多孔结构.粘结拉伸结果表明复合涂层与基体结合良好,较纯HA涂层与基体的结合强度有较大提高.复合涂层试样于SBF中浸泡2d、7d和14d的SEM分析结果表明复合涂层表面的磷灰石形成量较高.电位动力学曲线分析表明复合涂层可以提高基体的耐蚀性.     

以葡萄糖为造孔剂制备多孔羟基磷灰石涂层

采用电泳沉积方法在钛基材表面制得羟基磷灰石(hydroxyapatite,HA)/葡萄糖复合涂层,经烧结处理得到多孔HA涂层。采用红外光谱仪、扫描电镜、X射线衍射和热重分析表征了涂层的组成、表面形貌、物相组成及热稳定性,黏结-拉伸实验测定涂层与基体的结合强度,人体模拟体液(simulated body fluid,SBF)浸泡测定涂层的生物亲合性。结果表明:经700℃烧结处理,复合涂层中的葡萄糖微粒热分解得到多孔HA涂层,孔径为2～20μm,涂层与基体的结合强度可达17.6MPa;在1.5倍SBF(各离子浓度为SBF的1.5倍)中浸泡5d后,多孔HA涂层表面碳磷灰石化,呈现良好的生物亲合性。     

氧化铝基体上羟基磷灰石/氟羟基磷灰石双层涂层的制备及性能

通过涂覆-烧结法在氧化铝(Al_2O_3)表面制得羟基磷灰石(HA)/氟羟基磷灰石(FHA)双层涂层,HA和FHA重复沉积在氧化铝基体上形成均匀涂层,然后在1300 ℃进行热处理.在此过程中,如果没有FHA中间层,HA会和Al_2O_3发生严重的反应,形成磷酸三钙和钙铝化合物.SEM、XRD及粘接拉伸试验表明:FHA中间层能有效地抑制HA与Al_2O_3的反应,所获得的双层涂层具有多孔粗糙的表面,但与Al_2O_3基体结合紧密.涂层经1300 ℃热处理后,其结合强度约为30 MPa.     

HA/SiO2/Fe2O3复合涂层的制备及其在 HEPES模拟体液中的生物活性

采用电泳沉积法制备了HA/CS/SiO2/Fe2O3复合涂层,经700℃烧结2 h后得到HA/SiO2/Fe2O3复合涂层,并通过FT-IR、SEM、EDS、XRD、万能材料试验机、电化学工作站进行测试与表征。同时研究了HA/SiO2/Fe2O3复合涂层材料对枯草芽孢杆菌的抑菌性能,采用2-[4-(2-羟乙基)-1-哌嗪基]乙磺酸(HEPES)模拟体液培养,对复合涂层的体外生物活性进行评价。实验结果表明,HA/SiO2/Fe2O3复合涂层与钛基体间的结合强度达31.9 MPa,在HEPES模拟体液中培养14 d后,复合涂层表面碳磷灰石化,同时复合涂层粉体对枯草芽孢杆菌的抑菌率达到81.9%。因此,HA/SiO2/Fe2O3复合涂层具有较强的结合强度和较高的生物活性,并且具有一定的抑菌性,有望开发成为人体骨骼替代植入材料。     

茶多酚提取方法进展

本文综述了国内外现有茶多酚提取方法的现状以及近期的研究进展，并对其优缺点进行了评价。这将有助于中低档茶的综合利用和茶多酚的进一步开发应用。     

COMPARISON OF METHODS OF ANALYSIS OF GYPSUM1

The different analytical methods proposed for the evaluation of gypsum have been subjected to an experimental test. A combination method, consisting of a fusion with KHCO₃ and determination of CaO by KMnO₄ titration, the SO₃ by Andrews method of titration of BaCrO₄ has been found to give very reliable results with the least consumption of time.     

HEASUREHENT OF INSTANTANEOUS RATES OF LOSS OF VOIATILE COMPOUNDS DURING DRYING OF DROPS

A novel technique serves to monitor instantaneous rates of loss of a volatile solute from a suspended drop during drying. A highly sensitive electron capture detector is used to monitor concentrations of SF6 released into a flowing gas stream from a suspended, drying drop. Simultaneously, the appearance and morphological development of the drop are monitored with a video camera. This provides the wherewithal of relating instantaneous rates of loss of the volatile solute to particular events during the development of particle morphology.

Initial experiments have been carried out with drops of aqueous solutions of glucose, sucrose, maltodextrin and coffee extract. The results clearly display the onset of the volatiles-retentive selective diffusion phenomenon. There is also substantial loss of the volatile component later in the drying process, when the drops undergo repeated ex ansion, bursting and cratering due to the formation of internaf bubbles. These experiments appear to be the first quantitative demonstration of major losses accompanying changes in drop morphology.     

氢气纯度分析方法准确性的探讨

ONACCURACYOFANALYSISOFOFHYDROGEN1前言我公司目前应用的氢气纯度分析方法有两种,一种是爆炸反应法,另一种是焦性没食子酸吸收法。几年来,人们对两种分析方法的准确性曾有过褒贬不一的评论。这里我们也谈谈自己粗浅的观点。2爆炸法测定氢气纯度一定量的氢气样品与适量的空气之均匀混合物因反应后生成液体水而引起气体体积减少,减少的体积等于参加反应气体体积之和。其中l／3为氧气,2／3为氢气。根据氢气取样量和反应前后混气体体积之差,以及氢气在反应中的体积比例关系,可计算出样品的氢气纯度。计算公式式中：A一混…     

SEDIMENTATION OF BINARY MIXTURES OF PARTICLES OF UNEQUAL DENSITIES AND OF DIFFERENT SIZES

A model is developed for the sedimentation from a suspension of two particle species of unequal densities and of different sizes. The composition and the thickness of various layers in the sediments are predicted using graphical and analytical methods. The model predictions were in excellent agreement with experimental results, when the particle size ratio was ≥ 108. When size ratio of the particles was 2.60 and 4.31 the agreement occurred in about 50 percent of the cases.     

环氧树脂羟基值测定方法的研究

利用乙酸酐、吡啶和浓硫酸混合的乙酰化试剂测定环氧树脂中羟基值含量的方法具有操作简便、滴定终点明显和分析结果误差小等优点。     

骑式摩托车油箱喷涂工艺的改进

面对日益激烈的市场竞争,摩托车油箱外观质量越来越成为影响销售的因素之一。文章介绍了改进工艺后的油箱涂装,该涂装体系提高了油箱外观的丰满度,降低了油箱涂装的生产成本。     

ANALYSIS OF RECENT MEASUREMENTS OF THE VISCOSITY OF GLASSES

Viscosity of Simple Soda-Silicate 500° to 1400°C Comparison of the results given by English with those of Washburn, Shelton and Libman, indicates a discrepancy in the absolute values of log₁₀ viscosity amounting to 0.6, those of Washburn et al., being relatively too high. If correction for this is made, the isothermal curves of log₁₀ viscosity as a function of soda content are smooth up to 50% Na₂O, showing no inflection. The observations as a function of temperature T are all represented within accidental error by an equation of the type where all three constants vary regularly with the composition. Change of Viscosity of Glass (6SiO₂, 2Na₂O) due to Molecular Substitution of CaO, MgO and Al₂O₃ for Na₂O The effect is clearly brought out by plotting (from the results of English) the change of log₁₀η due to the substitution as a function of temperature. The curves each show a sharp bend at a temperature between 840° and 1050°C, which is designated the aggregation temperature T_a. If we divide these curves by the corresponding percentage substituted, we get curves for each oxide which are straight and parallel below the aggregation temperatures, the slopes (increase of change of log₁₀η per 100°C) being −0.056 (CaO), −0.055 (MgO), −0.018 (A1₂O₃) per per cent oxide substituted. For substitution of 1/2 molecule the slopes are −0.325 (CaO), −0.23 (MgO) and −0.18 (Al₂O₃) per 100°. At the aggregation temperature the change of log₁₀η per per cent is a minimum, 0.03 to 0.06 for CaO, 0.12 for MgO, 0.07 for Al₂O₃. Evidence of Aggregation in Glasses, from viscosity Measurements The sharp bends in the plots of change of log₁₀η due to substitution of an oxide for Na₂O, suggest the beginning of molecular aggregation at these temperatures. These aggregation temperatures are close to the devitrification temperatures, but the effect on the viscosity curves cannot be due to actual devitrification since it does not change with time. Taking the aggregation temperatures as equal to devitrification temperatures, additional isotherms are roughly sketched into the equilibrium triangle of the system Na₂O-CaO-SiO₂. Change of Viscosity of Glass (4SiO₂, 2Na₂O) due to of Substitution of B₂O₃ for SiO₂ The change of log₁₀η (from the results of English) is plotted as a function of temperature, and also the change of log₁₀η per per cent B₂O₃. The curves are more complex than for the substitution for Na₂O.     

酚醛树脂热降解动力学研究

用热失重非等温法对不同甲醛,苯酚魔鬼洋比的酚树脂进行了热降解动力学研究。结果表明,甲醛,苯酚摩尔比为１．５时,酚醛树旨的热发活化能最高。耐热性最好。     

剪力对梁变形影响的分析

本文用材料力学的分析方法,导出了一个计入剪力时梁的挠曲线的微分方程式。为了估计剪力对梁变形的影响,在集中力作用下梁内剪力用一个单值连续的反三角函数表示。由能量法确定了截面因子数值之后,定量地给出计入剪力时梁变形的分析结果。其结果和弹性力学的结来是一致的。