纳米磷酸钙复合骨支架体内降解的实验研究

研究纳米磷酸钙复合氧化铝氧化镁生物玻璃骨组织工程支架在动物体内的降解特性,为进一步构建组织工程化纳米人工骨提供研究依据;本研究将合成灭菌后的纳米磷酸钙复合骨支架植入新西兰大白兔股部肌袋,并在植入4、8、12、16 w取材进行大体、组织学、电镜观察降解情况,16 w时将取出的材料煅烧,测量残余无机物含量,同时进行X线衍射实验,测量残余材料的晶相组成.结果是:合成的纳米磷酸钙复合骨支架孔隙率为80%,孔径200～450 μm,抗压强度为3.8 MPa.材料在动物体内前8 w内降解较慢,生物力学强度减低不明显,12 w后降解明显加速,强度明显减低,并有羟基磷灰石成分出现,煅烧后残余无机物最少,16 w明显新骨形成,降解残余材料分布于新形成的骨组织内部,羟基磷灰石成分明显增多.结论显示纳米磷酸钙复合骨支架具有较好的降解性、生物相容性和诱导成骨作用,可作为骨组织工程的支架材料.     

ZnO表面改性Zn-Cu组织工程支架的研究

目的 利用ZnO对Zn-Cu组织支架材料进行表面改性,以提高其亲水性和抑菌、抗菌性能.方法 采用气压渗流铸造法制备了理论孔隙率约为60％的Zn-xCu(x=0,1,2,3)合金组织工程支架,并利用水热法对Zn-xCu(x=0,1,2,3)组织工程多孔支架进行ZnO表面修饰.采用扫描电子显微镜、X射线衍射仪,对制备的多孔...     

纳米针状表面改性的仿生多孔钛植入体及体外成骨性能（英文）

通过冷冻铸造和热氧化法制备一种新型兼具抗菌功能和良好骨整合性能的纳米针状表面改性仿生多孔钛植入体。分析和表征仿生多孔钛植入体的孔隙形貌和尺寸、力学性能和体外成骨性能。结果表明:当控制冷冻铸造工艺中浆料中钛粉体积比为10%时,多孔试样的孔隙度为(58.32±1.08)%、孔径为(126.17±18.64)μm、压缩强度为(58.51±20.38)MPa、弹性模量为(1.70±0.52)GPa。在1200°C烧结1 h,多孔试样的孔隙度为(58.24±1.50)%、孔径为(124.16±13.64)μm、压缩强度为(54.77±27.55)MPa、弹性模量为(1.63±0.30)GPa。通过热氧化方法在多孔钛植入体试样的孔隙表面制备出均匀分布的纳米针状结构。通过对工艺的优化,制备出具有良好孔隙形貌和尺寸,同时具备良好力学性能和体外成骨性能的纳米针状表面改性仿生多孔钛植入体,具有重要的临床应用前景。     

多孔镁表面生物活性β-TCP涂层的制备及其细胞相容性研究

采用化学沉积法在镁支架表面制备生物活性的β-TcP(磷酸三钙陶瓷)涂层,利用X射线衍射,扫描电子显微镜研究β-TCP涂层的相结构和表面形貌.并对表面改性的镁支架与类成骨细胞UMR106的体外生物相容性进行了详细研究.结果表明,表面改性后的镁支架浸提液细胞毒性为1级,即无细胞毒性;材料浸提液无细胞DNA毒性,对细胞周期无改变,也无异倍体细胞出现.实验结果证明,表面改性后的多孔镁具有良好的细胞相容性,是一种很有前景的新型骨组织工程支架材料.     

多孔Ta-10%Nb支架制备及其体外生物性能评价（英文）

通过海绵浸渍法和烧结技术制备得到组织工程用的高孔隙Ta-10%Nb支架材料,该材料的孔隙尺寸为300～600μm,孔隙率达到(68.0±0.41)%,同时开孔率高达(93.5±2.6)%。研究表明,制备得到的Ta-10%Nb支架材料具有与人体骨组织相似的弹性模量(2.54±0.5) GPa和抗压强度(83.43±2.5) MPa。同时,这种材料具有良好的三维空间结构单元,通过在该材料上进行鼠MC3T3-E1细胞共培养发现,细胞能很好地粘附生长和增殖。该材料所具备的良好生物力学性能和生物相容性能,使其在生物医学组织工程支架材料应用中具有良好的应用前景。这种多孔金属材料拥有良好的孔隙结构单元、适当的孔隙率以及大的表面积,使得该材料与细胞发生良好的作用。     

多孔钛骨组织工程支架设计及孔结构表征

针对目前骨组织工程支架微孔结构难以准确设计制备的问题,提出了一种基于点云的参数化建模+3D打印新方法。通过提取cube(C)、diamond(D)、gyroid(G)3种结构的型面函数点云数据,完成对不同孔结构特征的参数化建模。通过对模型有限元力学分析,对不同孔结构特征的多孔钛骨组织支架进行力学设计与订制。借助激光选区熔融(SLM)3D打印技术,完成对不同孔特征的骨组织支架快速成型。对多孔钛骨组织支架进行了相关材料学表征,包括孔结构表征与力学性能测试。结果表明:参数化模型的快速成型制造,能够有效地设计制备钛合金骨组织工程支架的孔结构特性,且可有效设计订制支架的力学性能,从仿生的角度实现多孔钛合金骨组织工程支架生物学功能的设计优化。     

酸蚀处理时间对种植体表面特性的影响规律

利用酸蚀处理技术对Al2O3喷砂处理后的种植体表面进行改性处理。采用扫描电镜(SEM)、表面接触角分析仪、表面轮廓仪等研究酸蚀处理后种植体的表面形貌、粗糙度和亲水性等表面特性。结果表明:酸蚀处理可促使种植体表面形成了多孔洞结构,进而改变其表面特性;当酸蚀处理20min时,种植体表面形成了蜂窝状多级孔洞结构,其表面粗糙度Ra为(1.77±0.064)μm、表面接触角为(47.7±3.022)°,有利于种植体与骨组织形成骨性结合。     

超疏水泡沫镍材料的制备及其油水分离性能∗

针对目前油水分离方法分离效率低、重复利用率低、二次污染环境等问题,开展了疏水三维多孔油水分离材料的研究。 以泡沫镍为基底材料,通过水热法构造多级微纳复合结构表面和氟硅烷疏水化处理得到超疏水泡沫镍。 利用扫描电子显微镜、能谱仪、X-射线衍射仪和全反射傅里叶变换红外光谱仪、接触角测量仪表征其表面形貌、成分和疏水性能,测试改性泡沫镍的油水分离性能和重复利用率。 结果表明:在泡沫镍表面成功制备出“鸟巢状”垂直排列的 Ni(OH)₂纳米片阵列,并形成局部“团簇状”凸起,协同泡沫镍本身微米级孔骨架构成多级微纳米粗糙结构,具有低表面能的氟硅烷成功组装在多级微纳结构表面,实现了优异的超疏水性能。 改性泡沫镍可实现对甲苯、氯仿、正己烷与水的混合物吸附分离,且具有良好的循环使用性。 制备的超疏水泡沫镍可在磁场控制下实现对油水混合物的分离,是一种高效、智能的油水分离三维多孔材料。     

低粘附超疏水金属网的制备及在溢油清理中的应用

目的寻找一种高效、便捷的海上清理油污的方法。方法通过水热法在光滑的不锈钢金属网基底上生长出具有纳米柱状结构的氧化锌晶体,然后用低表面能的长链硅烷对氧化锌金属网进行表面改性,制备出具有超疏水-超亲油性能的金属网材料。通过扫描电镜、透射电镜、X射线衍射、红外光谱、接触角测试、粘附力测试等手段对材料表面的微观形貌、化学成分和润湿性能进行分析。结果改性后的金属网材料表面覆盖了均匀的氧化锌微纳米结构,氧化锌晶体柱的长度约为3~5μm,截面呈现出很规则的六边形形貌。低表面能处理后的氧化锌表面变得模糊,但结构并未发生变化。与空白金属网相比,改性后的金属网对水的接触角达到154°,对油滴接触角为0°。该金属网材料可以自动收集并回收水面上的溢油,对多种油类和有机溶剂的回收效率均高于95%,循环吸油10次后依然具有90%的回收效率。同时该金属网材料还具有良好的耐磨性能,经过胶带剥离50次或800#砂纸打磨后涂层仍保持着良好的超疏水性。结论在氧化锌微纳米结构与低表面能物质的共同作用下,金属网表面具有了优异的超疏水-超亲油性能,可以自动收集水上的油污,具有较高的油水分离效率和较好的涂层稳定性,适用于海上溢油的清理。     

硅烷偶联剂对β一偏磷酸钙晶须的表面改性研究

为了改善β-偏磷酸钙晶须(β-CMPw)的疏水性能,采用八甲基环四硅氧烷(D4)和乙烯基三乙氧基硅烷(A-151),在超声分散条件下对β-CMPw进行了表面改性.采用润湿性试验测定晶须的硫水性能,通过扫描电镜(SEM)、热分析(TG-DSC)研究了超声时间和改性剂种类、含量对表面改性的影响.结果表明:晶须改性后的疏水性均优于未改性的晶须,获得了较佳的表面改性条件,即改性剂选用D4,超声时间20min,所加改性剂的质量分数为2%.     

Effects of Post-weld Heat Treatment on Microstructure,Mechanical Properties and the Role of Weld Reinforcement in 2219 Aluminum Alloy TIG-Welded Joints

In as-welded state, each region of 2219 aluminum alloy TIG-welded joint shows diff erent microstructure and microhardness due to the diff erent welding heat cycles and the resulting evolution of second phases. After the post-weld heat treatment, both the amount and the size of the eutectic structure or θ phases decreased. Correspondingly, both the Cu content in α-Al matrix and the microhardness increased to a similar level in each region of the joint, and the tensile strength of the entire joint was greatly improved. Post-weld heat treatment played the role of solid solution strengthening and aging strengthening. After the post-weld heat treatment, the weld performance became similar to other regions, but weld reinforcements lost their reinforcing eff ect on the weld and their existence was more of an adverse eff ect. The joint without weld reinforcements after the post-weld heat treatment had the optimal tensile properties, and the specimens randomly crack in the weld zone.     

The First Phase of the SRIF Industrialized Base in ＂West Area＂ Has Been Put into Operation

After nearly two years＇ tense construction, the first phase of industrialized base of Shenyang Research Institute of Foundry （SRIF）, located at the Tiexi Casting and Forging Industrial Park in the west of Tiexi District, has now been completed and formally put into operation.     

Thermodynamics Study on the Decomposition of Chromite with KOH

Institute of Process Engineering, Chinese Academy of Sciences, China, has proposed a method for oxidative leaching of chromite with potassium hydroxide. Understanding the mechanism of chromite decomposition, especially in the potassium hydroxide fusion, is important for the optimization of the operating parameters of the oxidative leaching process. A traditional thermodynamic method is proposed and the thermal decomposition and the reaction decomposition during the oxidative leaching of chromite with KOH and oxygen is discussed, which suggests that chromite is mainly destroyed by reactions with KOH and oxygen. Meanwhile, equilibrium of the main reactions of the above process was calculated at different temperatures and oxygen partial pressures. The stable zones of productions, namely, K2CrO4 and Fe2O3, increase with the decrease of temperature, which indicates that higher temperature is not beneficial to thermodynamic reactions. In addition, a comparison of the general alkali methods is carried out, and it is concluded that the KOH leaching process is thermodynamically superior to the conventional chromate production process.     

Influence of Heat Treatment on Damping Behaviour of the Magnesium Wrought Alloy AZ61

The effect of isochronal heat treatments for 1h on variation of damping, hardness and microstructural change of the magnesium wrought alloy AZ61 was investigated. Damping and hardness behaviour could be attributed to the evolution of precipitation process. The influence of precipitation on damping behaviour was explained in the framework of the dislocation string model of Granato and Lücke.     

Effect of Rare Earth Doping on Impedance,Modulus and Conductivity Properties of Multiferroic Composites:0.5(BiLa_xFe_(1-x)O_3)–0.5(PbTiO_3)

The Lanthanum-doped bismuth ferrite–lead titanate compositions of 0.5(Bi LaxFe1-xO3)–0.5(Pb Ti O3)(x = 0.05,0.10,0.15,0.20)(BLxF1-x-PT) were prepared by mixed oxide method.Structural characterization was performed by X-ray diffraction and shows a tetragonal structure at room temperature.The lattice parameter c/a ratio decreases with increasing of La(x = 0.05–0.20) concentration of the composites.The effect of charge carrier/ion hopping mechanism,conductivity,relaxation process and impedance parameters was studied using an impedance analyzer in a wide frequency range(102–106Hz) at different temperatures.The nature of Nyquist plot confirms the presence of bulk effects only,and non-Debye type of relaxation processes occurs in the composites.The electrical modulus exhibits an important role of the hopping mechanism in the electrical transport process of the materials.The ac conductivity and dc conductivity of the materials were studied,and the activation energy found to be 0.81,0.77,0.76 and 0.74 e V for all compositions of x = 0.05–0.20 at different temperatures(200–300 °C).     

Quantitative Analysis of the Crystallographic Orientation Relationship Between the Martensite and Austenite in Quenching–Partitioning–Tempering Steels

The orientation relationships(ORs)between the martensite and the retained austenite in low-and medium-carbon steels after quenching–partitioning–tempering process were studied in this work.The ORs in the studied steels are identified by selected-area electron diffraction(SAED)as either K–S or N–W ORs.Meanwhile,the ORs were also studied based on numerical fitting of electron backscatter diffraction data method suggested by Miyamoto.The simulated K–S and N–W ORs in the low-index directions generally do not well coincide with the experimental pole figure,which may be attributed to both the orientation spread from the ideal variant orientations and high symmetry of the low-index directions.However,the simulated results coincide well with experimental pole figures in the high-index directions{123}_(bcc).A modified method with simplicity based on Miyamoto’s work was proposed.The results indicate that the ORs determined by modified method are similar to those determined by Miyamoto’method,that is,the OR is near K–S OR for the low-carbon Q–P–T steel,and with the increase of carbon content,the OR is closer to N–W OR in medium-carbon Q–P–T steel.     

Using Finite Element and Contour Method to Evaluate Residual Stress in Thick Ti-6Al-4V Alloy Welded by Electron Beam Welding

This work was to reveal the residual stress profile in electron beam welded Ti-6Al-4V alloy plates(50 mm thick) by using finite element and contour measurement methods.A three-dimensional finite element model of 50-mmthick titanium component was proposed,in which a column–cone combined heat source model was used to simulate the temperature field and a thermo-elastic–plastic model to analyze residual stress in a weld joint based on ABAQUS software.Considering the uncertainty of welding simulation,the computation was calibrated by experimental data of contour measurement method.Both test and simulated results show that residual stresses on the surface and inside the weld zone are significantly different and present a narrow and large gradient feature in the weld joint.The peak tensile stress exceeds the yield strength of base materials inside weld,which are distinctly different from residual stress of the thin Ti-6Al-4V alloy plates presented in references before.     

Microstructures and Tensile Properties of Ultrafine-Grained Ni–(1–3.5) wt% SiC_(NP) Composites Prepared by a Powder Metallurgy Route

Silicon carbide nanoparticle-reinforced nickel-based composites(Ni–Si CNP),with a Si CNPcontent ranged from1 to 3.5 wt%,were prepared using mechanical alloying and spark plasma sintering.In addition,unreinforced pure nickel samples were also prepared for comparative purposes.To characterize the microstructural properties of both the unreinforced pure nickel and the Ni–Si CNPcomposites transmission electron microscopy(TEM) was used,while their mechanical behavior was investigated using the Vickers pyramid method for hardness measurements and a universal tensile testing machine for tensile tests.TEM results showed an array of dislocation lines decorated in the sintered pure nickel sample,whereas,for the Ni–Si CNPcomposites,the presence of nano-dispersed Si CNPand twinning crystals was observed.These homogeneously distributed Si CNPwere found located either within the matrix,between twins or on grain boundaries.For the Ni–Si CNPcomposites,coerced coarsening of the Si CNPassembly occurred with increasing Si CNPcontent.Furthermore,the grain sizes of the Ni–Si CNPcomposites were much finer than that of the unreinforced pure nickel,which was considered to be due to the composite ball milling process.In all cases,the Ni–Si CNPcomposites showed higher strengths and hardness values than the unreinforced pure nickel,likely due to a combination of dispersion strengthening(Orowan effects) and particle strengthening(Hall–Petch effects).For the Ni–Si CNPcomposites,the strength increased initially and then decreased as a function of Si CNPcontent,whereas their elongation percentages decreased linearly.Compared to all materials tested,the Ni–Si CNPcomposite containing 1.5% Si C was found more superior considering both their strength and plastic properties.     

Directional Growth of Tin Crystals Controlled by Combined Solute Concentration Gradient Field and Static Magnetic Field

A new method was introduced to achieve directional growth of Sn crystals. Microstructures in liquid(Pb)/liquid(Sn) diffusion couples were investigated under various static magnetic fields. Results show that the β-Sn crystals mainly reveal an irregular dendritic morphology without or with a relatively low static magnetic field(B0.3 T). When the magnetic field is increased to 0.5 T, the β-Sn dendrites close to the final stage of growth begin to show some directional character. With a further increase in the magnetic field to a higher level(0.8–5 T), the β-Sn dendrites have an enhanced directional growth character, but the dendrites show a certain deflection. As the magnetic field is increased to 12 T, the directional growth of the β-Sn dendrites in the center of the couple is severely destroyed. The mechanism of the directional growth of the β-Sn crystals and the deflection of the β-Sn crystals with the application of static magnetic field was tentatively discussed.     

电化学噪声数据处理方法概述

综述了常见的电化学噪声数据处理方法,介绍了直流趋势剔除、统计分析、快速傅立叶变换(FFT)法计算功率谱密度(PSD)以及小波变换处理电化学噪声信号的基本过程,并阐释了各种数学处理及所得参数的物理意义。