Investigation for Electrophoretic Deposition of Hydroxyapatite Coatings and the Surface Modification of Coatings

羟基磷灰石（Ca10(PO4)6(OH)2，HA）是人骨等硬组织的主要无机成分，具有良好的生物相容性和高的生物活性，被广泛用作为生物医用植入材料。然而，HA陶瓷材料的力学性能较差，限制了它在生物医学领域的应用。为此人们致力于发展各种HA涂层或复合材料。在医用金属上涂覆HA涂层是目前复合生物医学材料领域研究的热点之一。电泳沉积法可在复杂形貌的基体上获得均匀的涂层并且涂层的结构和成分可控。这些独特的优势使其在HA陶瓷涂层的制备中引起了广泛的兴趣。但是电泳沉积法制备HA陶瓷涂层普遍存在着结合强度不够高的问题。为了改善电泳沉积法制备的HA涂层的结合强度并进一步提高HA涂层的生物学性能，本论文在实验室课...Hydroxyapatite (Ca10(PO4)6(OH)2, HA), the major inorganic component of human bone and other hard tissues, has been used extensively for biomedical implant applications due to its good bioactivity and excellent biocompatibility. However, the poor mechanical properties of HA ceramic have limited its clinical applications. For this reason, a great deal of research has concentrated on the development...学位：工学硕士院系专业：化学化工学院化学工程与生物工程系_化学工程学号：2062007115088

FABRICATION OF HYDROXYAPATITE/ALUMINUM OXIDE COMPOSITE COATINGS BY THE COMBINATION OF ELECTROPHORETIC DEPOSITION AND REACTION BONDING PROCESS

在金属表面用电泳沉积(electrophoretic deposition,EPD)法制备羟基磷灰石(hydroxyapatite,HA)涂层的主要问题是结合强度较低。为了提高HA涂层与基体的结合强度,先采用EPD在钛表面制得羟基磷灰石/铝(hydroxyapatite/aluminum,HA/Al)复合涂层,然后采用反应结合方法(reaction bonding process)制备羟基磷灰石/氧化铝(hydroxyapatite/aluminum oxide,HA/Al2O3)复合涂层,并与相同条件下制备的HA单一涂层进行比较研究。用扫描电镜表征涂层的表面和横截面形貌。用能量散射X射线衍射(X-ray diffraction,XRD)谱分析HA/Al2O3复合涂层的化学组成。用XRD仪研究涂层的物相组成和热稳定性。通过黏结–拉伸实验测定HA涂层与基体的结合强度。结果表明:通过850℃热处理,HA/Al复合涂层中的Al粉发生氧化反应生成Al2O3,经反应结合得到HA/Al2O3复合涂层;反应结合提高了HA涂层的致密化程度且降低了基底钛表面的氧化程度;与单一HA涂层相比,HA/Al2O3复合涂层与基底间的结合强度得到明显提高。The major problem in fabricating hydroxyapatite (HA) coating on metal substrate by electrophoretic deposition is the low bonding strength between the coating and substrate. In order to improve the bonding strength,hydroxyapatite/aluminum oxide (HA/Al2O3) composite coating was fabricated on titanium substrate using the combination of electrophoretic deposition and reaction bonding process. The HA single coating was prepared in the same conditions for comparison. Scanning electronic microscope was employed to characterize the surface and cross-sectional morphologies of the as-prepared coatings. The chemical compositions of the composite coating were analyzed through energy dispersive X-ray spectroscopy. X-ray diffraction was used to study the phase com-position and thermal stability of the as-prepared coatings. The bonding strength between the coating and substrate was tested by a shear strength testing experiment. The results show that the Al in HA/Al green coating prepared by the EPD was oxidized to Al2O3,and HA/Al2O3 composite coating was obtained using the reaction bonding process by heat treatment at 850 ℃. The reaction bonding process promotes the coating's sintering densification and improves the substrate's oxidation resistance during the heat treatment. In comparison with the HA single coating,the HA/Al2O3 composite coating exhibits much higher bonding strength.国家自然科学基金(20573086);; 国家科技支撑计划(2007BAE05B04);; 厦门市科技计划(3502Z20063005)资助项

EFFECTS OF SUSPENSION POWDER CONTENT ON THE ELECTROPHORETIC DEPOSITION OF HYDROXYAPATITE COATINGS

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5 g/L时的4.54 MPa,提高到悬浮液HA粉体含量为20 g/L时的19.92 MPa。Hydroxyapatite(HA) coatings were deposited on titanium substrate by electrophoretic deposition in suspensions with dif-ferent HA powder contents.The surface and cross-sectional morphologies and phase composition of the as-prepared coatings were characterized by scanning electronic microscopy and X-ray diffraction.The bonding strength between the coating and substrate was tested by a shear strength testing experiment.The results show that suspension HA powder content has a significant effect on the mi-crostructure of the deposited coating,and further on its sintering property and the bonding strength between the coating and substrate.The increase in suspension HA powder content is beneficial in producing dense green coating,improving the sintering process of coating and the oxidation resistance of the substrate,and consequently increasing the bonding strength.The bonding strength between the HA coating and titanium substrate can be increased from 4.54 MPa with a suspension HA powder content of 5 g/L to 19.92 MPa with a suspension HA powder content of 20 g/L.国家自然科学基金(20573086);; 国家科技支撑计划(2007BAE051304);; 厦门市科技计划(3502Z20063005)资助项

Seasonal Variation on Nutrient Limitation for Phytoplankton Growth in a Coastal River-Reservoir System,Southeast China

选取厦漳泉三地市饮用水源地九龙江20条支流以及4个水库开展2013~2014年为期一年的逐月水质与生态调查与监测,并借助gIS、统计分析方法,识别了氮磷营养盐和浮游植物藻类丰度和群落的时空变异性,河流与水库氮磷营养盐限制的差异性以及其控制性的季节性变化特征.结果表明,九龙江支流和水库的营养盐、藻类丰度和群落都分别展示出明显的时空变异性.支流和水库均呈现营养盐氮素浓度冬春季节较高,夏秋季节较低;营养盐磷素浓度大体与之相反.水库藻类丰度于夏季最高,而支流藻类丰度呈现冬春季节较高,夏秋季节较低的趋势.其中,汀溪水库于秋冬春季节和夏季呈现硅藻,绿藻演替;江东库区于冬春,夏秋季节呈现绿藻-隐藻、绿藻-蓝藻演替;石兜-坂头水库以及支流均未出现季节演替现象,优势藻分别为蓝藻、绿藻.rdA排序图较好地显示了浮游植物藻类与环境因子之间的关系.水库叶绿素A与氮磷营养盐之间呈现显著相关性,相关关系较强,并且其相关关系在冬春季节呈现营养盐磷的限制性,夏秋季节呈现营养盐氮的限制性.相比于水库,支流叶绿素A与营养盐之间只有夏秋季节呈现显著相关性,且相关关系较弱.A comprehensive analysis was conducted using a dataset obtained from October in 2013 to October in 2014 monitoring in 20 headwater streams of Jiulong River and four reservoirs,situated in such a coastal river-reservoir system in Southeast China suffering from intensive anthropogenic disturbance.In-situ monitoring,GIS and statistical analysis were coupled in this study to identify the spatiotemporal variations of nutrients & phytoplankton abundance and community structure,the differentiation of nitrogen & phosphorus limitation of phytoplankton growth,and the seasonal variations in nutrient limitation of phytoplankton growth.The results showed that there were obvious spatiotemporal variations in terms of nutrients & phytoplankton abundance and community structure in the 20 headwater streams and four reservoirs.The concentration of nitrogen was higher in winter and spring whereas lower in summer and autumn for both 20 headwater streams and four reservoirs.However,the concentration of phosphorus showed an opposite trend.The phytoplankton's abundance was the highest in summer for four reservoirs while it was higher in winter and spring,lower in summer and autumn in the 20 headwater streams.Meanwhile,the main trend in the succession of phytoplankton was from Bacillariophyta in autumn,winter and spring to Chlorophyta in summer in Tingxi reservoir,from Chlorophyta-Cryptophyta in winter and spring to Chlorophyta-Cyanophyta in summer and autumn in Jiangdong reservoir.No obvious trend exhibited in phytoplankton succession in Shidou-Bantou reservoir and 20 headwater streams.The Redundancy analysis( RDA) ordination plots well displayed the phytoplankton's community structure and its relationships with environmental factors.Besides,according to linear regression analysis there was a closer correlation between chlorophyll-a and nutrients in four reservoirs than in 20 headwater streams.In four reservoirs,N limitation was preliminarily observed in autumn whereas P limitation exhibited in winter.国家科技支撑计划项目(2013BAC06B01); 国家自然科学基金项目(41471154

荧光分析法测定金属铝箔中的微量镓

Ga~(3+)与Al~(3+)两者离子半径相近,化学性质类似,因此镓是金属铝中常见的杂质之一。荧光法是金属铝中微量镓测定的常用方法。应用表面活性剂的,见于镓-荧光镓(或其同系物)测定体系。8羟基喹啉(Oxine)曾用于硅酸岩中微量镓的萃取-荧光测定。本文研究了Ga~(3+)-Oxine-表面活性剂体系荧光测定的合适条件,并应用于金属铝箔中微量镓的测定

复杂性后尿道狭窄81例治疗分析

目的探讨复杂性后尿道狭窄或闭锁的手术治疗方法,提高手术治疗效果。方法 1991～2008年收治的81例复杂性后尿道狭窄/闭锁患者,狭窄/闭锁段长度为3～10cm,其中>5cm者27例;66例曾有1～4次手术史;62例行改良尿道套入术,19例尿道端端吻合术;73例经会阴或腹会阴切口,8例经耻骨或切除部分耻骨下缘切口。15例应用尿道替代物成形。结果 76例(93.8%)术后排尿满意,5例失败,其中改良尿道套入术和尿道端端吻合术成功率分别为95.2%(59/62)、89.5%(17/19)(P>0.05)。15例应用尿道替代物成形术均取得成功。结论复杂性后尿道狭窄/闭锁的治疗应根据尿道病变情况选择不同的手术径路及术式,改良尿道套入术具有创伤小、操作简便、成功率高等优点。尿道狭窄段>5cm者应考虑应用尿道替代物成形

Nonextensive and extensive thermostatistic properties of Fermi systems trapped in different external potentials

Research Foundation of Ministry of Education, China [20050384005]; Science Research Fund, Huaqiao University, China [07BS105]The thermostatistic properties of a q-generalized Fermi system trapped in a generic power-law potential are studied, based on the generalized statistic distribution derived from the Tsallis entropy. The total number of particles, the total energy, and the heat capacity at constant volume of the system are derived. The thermostatistic characteristics of the system are discussed in detail. It is found that the thermostatistic properties of such a system depend closely on parameter q, dimensional number of the space, kinetic characteristics of particles and shapes of the external potential, and the external potential has a great influence on the thermostatistic properties of the system. Moreover, it is shown that the results obtained here are very general and can be used to unify the description of the nonextensive and extensive thermostatistic properties of a class of Fermi systems trapped in different external potentials so that the important conclusions of many typical Fermi systems in the literature may be directly derived from the present paper

The Influence of Suspension Properties on Electrophoretic Deposition of Hydroxyapatite Coatings

涂层裂纹控制和沉积速率的研究是设计和优化电泳沉积涂层的基础.悬浮液特性是影响电泳沉积涂层的关键因素之一.通过对不同PH条件下悬浮液的粒径、zETA电位、电导率和稳定性等参数的测定,探讨悬浮液特性参数对电泳沉积羟基磷灰石涂层过程中涂层裂纹控制和沉积速率的影响.结果表明:沉积速率随悬浮液PH的增加先增加后减小,并在PH 2.9附近获得最大值.此外,沉积速率还受陈化时间的影响.悬浮液PH对涂层裂纹控制有重要影响,在PH 2.9附近电泳沉积获得的涂层的裂纹最少.悬浮液在PH 2.9附近(电导率为11--12μS/CM)且陈化1--2 d是电泳沉积针状羟基磷灰石涂层的适宜条件.It is essential to study the crack controlling and deposition rate for the design and optimization of the coatings fabricated by the electrophoretic deposition(EPD) process.The property of the suspension is a key factor in the electrophoretic deposition of coatings.The parameters related to the property of the suspension such as particle size,zeta potential of the particle,conductivity and stability were characterized and then their effects on both the crack controlling and deposition rate in the electrophoretic deposition process of hydroxyapatite(HA) coatings were discussed.Results showed that the deposition rate increases at the first stage as the pH of the suspension increased and then decreased,gaining a maximum at the pH value of about 2.9.In addition,the aging time plays an important role in the deposition rate.Again,the pH of the suspension showed a significant influence on the crack controlling of HA coatings and cracks were minimized in the coating deposited from the suspension with a pH value of about 2.9.The suspension at pH 2.9 approximately with a conductivity of 11 μs/cm to 12 μs/cm and aging for 1 d to 2 d is appropriate for the electrophoretic deposition of needle-like HA coatings.国家自然科学基金(20573086

高超声速非平衡流动-辐射特性数值模拟研究

飞行器高超声速飞行过程中所承受对流加热和辐射加热可能具有相当的量级,因此合理准确预测气动加热需要将二者进行综合考虑.文章发展了具有非玻尔兹曼电子能级分布和振动能级分布的高温空气碰撞辐射模型,并耦合一维激波后流动方程计算不同飞行条件下激波后的非平衡流动特性,采用逐线辐射输运模型计算获得激波后非平衡辐射特性、辐射强度和辐射输运通量,深入比较分析了不同飞行高度和马赫数对非平衡流动和辐射输运过程的影响.计算结果表明对于高空高马赫飞行条件,其波后流动存在显著的热力学非平衡、化学非平衡和能级非平衡特征,在近激波区域高振动能级和原子高束缚电子激发态明显低于玻尔兹曼分布.在高空高马赫条件下真空紫外辐射占据主导地位,主要是由高能原子束缚-束缚跃迁造成的.随着高度和马赫数的下降,激波层内气体解离和电离程度降低,原子辐射贡献下降,分子辐射贡献增加,导致红外、可见光和紫外波段的辐射输运增强,真空紫外辐射输运过程减弱