增材制造多孔金属生物材料研究综述

增材制造的多孔金属生物材料广泛应用于植入物骨骼等生物医用工业领域,具有很大的发展潜力,目前,对多孔金属生物材料的研究主要聚焦在多孔生物材料的设计、制造与表面处理等方面.对比了不同增材制造技术的特点,并说明了粉床熔融技术最适合多孔金属生物材料的制造.同时,讨论了不同金属生物材料(生物惰性材料与降解材料)制造多孔生物材料的...     

生物医用复合材料研究现状及发展趋势

随着生物技术、医药技术、信息技术、制造技术、纳米技术和材料科学技术的迅猛发展与交互融合，新型和新概念生物医用材料层出不穷。药物控制释放材料、组织工程材料、纳米生物材料、生物活性材料、介入诊断和治疗材料、可降解和吸收生物材料、新型人造器官、人造血液等代表了新的发展趋势和方向。     

生物材料

<正>1生物材料发展概述1.1生物材料及其发展历史生物材料(Biomaterials)是近年来快速发展的新兴学科,是材料学、生命科学、医学、工程学的交叉融合,被广泛应用于临床医学、新型制造、生物技术等领域。狭义上的生物材料是指生物医用材料(Biomedical Materials),是一类用于诊断、治疗、修复或替换人体组织、器官或增进其功能的新型高技术材料。生物医用材料在临床     

可降解生物医用材料研究现状与展望

正生物医用材料,通常是指用于诊断与修复组织或器官等治疗疾病领域,对人体组织、器官及血液不产生影响与副作用的一类功能材料。材料科学的发展,使得人体中除了大脑以及大多数内分泌器官外的其他组织器官都可找到替代品。生物医用材料直接用于人体或与人体健康密切相关领域,因此对其应用范围与标准有严格的要求。不可降解生物材料在植入人     

中国生物医用材料的科研与产业化现状

<正>生物医用材料(或称生物材料)与生物系统相互接触后可以对生物体的组织、器官或功能进行诊断、治疗、增强或替代生物体内的任意组织、器官或功能,主要包括生物医用高分子材料、生物医用陶瓷材料、生物医用金属材料和生物医用复合材料等。生物医用材料是人工器官和医疗器械的基础,是材料科学的重要分支,目前已成为各国科学家竞相研究和开发的热点。     

复合纳米生物医用材料的研究

生物医用材料领域中,细胞与材料间的相互作用是研究的主要课题.材料表面的微观结构对细胞的生物调控作用更为重要.纳米材料因具有一些独特的效应,如体积效应和表面效应,有利于细胞黏附、增殖和功能表达,因而作为生物医用材料特别是组织工程支架材料具有良好的应用前景.目前用于生物医用研究的纳米材料主要有无机纳米材料、高分子纳米材料以及复合纳米材料等.仿生纳米材料的研究和利用极大地促进了组织工程学的发展.本文就近年来纳米材料在生物医用材料尤其是组织工程支架材料中的应用研究现状进行了综述.     

3D生物打印技术的发展与展望

<正>3D生物打印技术(3D bioprinting)是3D打印技术(即增材制造)的重要分支,是指按照增材制造原理,实现生物材料和"生物墨水"受控累积组装,从而制造医疗器械或辅助器具、组织工程支架、组织器官甚至生命体等的快速成型技术。30年来随着技术的进步与成熟,在生物医疗领域成功打印了包括体外模型、手术导板、骨/软骨、牙齿、气管、血管、眼球、汗腺、甚至肝肾心脏单元等,较好     

生物材料:新材料产业中的明珠

<正>"你是我的眼,带我穿越拥挤的人潮;你是我的眼,带我阅读浩瀚的书海……"歌词中的期许,如今可以利用生物材料制造的人工角膜来实现。生物材料再也不会只简简单单应用在软骨、支架等领域,通过组织工程化,人工角膜、人工肌腱、人工皮肤等产品正面向临床取得广泛的应用。事实上,生物材料内涵丰富、产品多样,涉及材料、生物、医学等多个领域,是典型的多学科融合产业,但目前商业上的应用主要还是集中在医学领域,又称生物医用材料。随着技术及工程化应用的不     

医用聚乳酸材料性能及加工方法研究进展EI

与天然降解高分子材料相比,人工合成高分子材料具有更好的力学性能、可控的降解性能及良好的生物相容性,因此广泛用于生物材料制品。聚乳酸是研究最多的人工合成高分子材料之一。文中围绕医用聚乳酸材料的性能及加工方法,首先介绍了聚乳酸体内降解规律及生物安全性的研究现状,其次综述了组织工程支架领域多种加工方法(熔融沉积3D打印、静电纺丝、气体发泡、相分离、冷冻干燥等)的技术特点,并概述了药物传输微球常用加工方法(喷雾干燥法、溶剂挥发法、其他方法)的研究进展,最后对聚乳酸材料性质、加工方法及在生物医学领域的应用前景进行了展望。     

生物材料对细胞生物学行为的影响

随着细胞生物学、基因工程等研究领域的发展,临床使用的生物医用材料已经由单纯的生物材料制成的植人物,发展成细胞与生物材料的复合物.生物医用材料不仅应具备生物安全性、生物相容性、血液相容性,还应该具有细胞外基质的作用.本文综述了生物材料作为细胞外基质,对细胞粘附、细胞生长及细胞凋亡的影响.     

Structural and optical properties of AlxOy/Pt/AlxOy multilayer absorber

We report on the microstructure and optical properties of Al_xO_y–Pt–Al_xO_y interference-type multilayer films, deposited by electron beam (e-beam) deposition onto corning 1737 glass, silicon (1 1 1) and copper substrates. The structural properties were investigated by Rutherford backscattering spectrometry, X-ray diffraction, scanning electron microscopy, energy dispersive X-ray spectroscopy and atomic force microscopy. The optical properties were extracted from specular reflection/transmission, diffuse reflectance and emissometer measurements. The stratification of the coatings consists of a semi-transparent middle Pt layer sandwiched between two layers of Al_xO_y. The top and bottom Al_xO_y layers were non-stoichiometric with no crystalline phases present. The Pt layer is in the fcc crystalline phase with a broad size distribution and spheroidal shape in and between the rims of Al_xO_y. The surface roughness of the stack was found to be comparable to the inter-particle distance. The optical calculations confirm a high solar absorptance of ∼0.94 and a low thermal emittance of ∼0.06 for the multilayer stack, which is attributed not only to the optimized nature of the multilayer interference stacks, but also to the specific surface morphology and texture of the coatings. These optical characteristics validate the spectral selectivity of the Al_xO_y–Pt–Al_xO_y interference-type multilayer stack for use in high temperature solar-thermal applications.     

Bulk crystalline BaPb34Bi14O3: A ceramic superconductor

The preparation conditions of the high T_C ceramic superconductor Ba(Pb,Bi)O₃ is correlated with the superconducting transition. Transition onsets of all materials are similar, but transition widths and transition completeness is strongly dependent on firing temperature. Only materials prepared over a narrow temperature range, resulting in a nearly ideal weight loss, have a complete and narrow transition.     

Electrostriction in Pb (Zn13Nb23)O3

The electrostriction in $\text{Pb (Zn}{}_{\mathrm{<mtext>1</mtext><mtext>3</mtext>}}\text{Nb}{}_{\mathrm{<mtext>2</mtext><mtext>3</mtext>}}\text{)}\text{O}{}_3$ crystals has been investigated using a strain gauge method. In the ferroelectric phase below 140 C, the strain vs the electric field shows a hysteresis, which is ascribed to the effect of ferroelectric domains. A quadratic relation holds between the strain x and the electric polarization P as x = QP² above about 170 C in the paraelectric phase. Values of the electrostrictive Q coefficients are determined from the measurements near 190 C, as Q₁₁ = 1.6·10^?2m⁴/C², Q₁₂ = ?0.86·10^?2m⁴/C², and Q₄₄ = 0.85·10^?2m⁴/C².     

Synthesis of a new perovskite Pb(Li14Nb34)O3

A high-pressure technique was adopted to obtain perovskite-type $\text{Pb(Li}{}_{\mathrm{<mtext>1</mtext><mtext>4</mtext>}}\text{Nb}{}_{\mathrm{<mtext>3</mtext><mtext>4</mtext>}}\text{)}\text{O}{}_3$. A new perovskite $\text{Pb(Li}{}_{\mathrm{<mtext>1</mtext><mtext>4</mtext>}}\text{Nb}{}_{\mathrm{<mtext>3</mtext><mtext>4</mtext>}}\text{)}\text{O}{}_3$ was characterized to have a cubic symmetry with $\text{a}{}_{\mathrm{<mtext>o</mtext>}}\text{= 4.069}\text{A}\text{?}$; Li and Nb ions in the B-site of perovskite lattice may be in a random arrangement.     

Magnetic,electrical and thermal studies on the V1−xMox02

The monoclinic-to-tetragonal structure transition of oxides V_1?xMo_x0₂ with $\text{0≤}\text{x}\text{≤0.20}$ has been studied by means of DTA, X-ray diffraction, magnetic susceptibility (powder samples) and electrical conductivity (single crystals) measurements within the temperature region 80 K to 400 K. A linear decrease of the transition temperature of 11 K per atom % Mo was observed. The magnetic susceptibility of the low temperature phase was found to be temperature independent paramagnetic for all preparations. Electrical conductivity measurements on the same phase showed crystals with $\text{x}\text{? 0.04}$ to be semiconducting, while a metallic behavior was observed in the region $\text{0.10 ?}\text{x}\text{? 0.14}$.     

n-PbTep+−Pb1−xSnxTe heterojunctions prepared by a modified hot wall technique

$\text{n-PbTe}\text{p}{}^{\mathrm{+}}\text{?}\text{Pb}{}_{\mathrm{1?x}}\text{Sn}{}_{\mathrm{x}}\text{Te}$ heterojunctions with a long wavelength spectral cutoff (λ_c ≈ 6 μm) were prepared using the double-channel hot wall technique. The electrical and photoelectrical properties of the heterojunctions at 77, 197 and 300 K were investigated. Detectors with R_oA equal to 170 Ω cm² and a quantum efficiency of 25–40% were obtained. Reasons for the shift of the long wavelength spectral cutoff of the heterojunctions towards shorter wavelengths are given.     

Optimization of AlxOy/Pt/AlxOy multilayer spectrally selective coatings for solar-thermal applications

Spectrally selective Al_xO_y/Pt/Al_xO_y multilayer absorber coatings were deposited onto corning 1737 glass, Si (111) and copper substrates using electron beam (e-beam) vacuum evaporator at room temperature. The employment of ellipsometric measurements and optical simulation was proposed as an effective method to optimize and deposit multilayer solar absorber coatings. The optical constants (n and k) measured using spectroscopic ellipsometry, showed that both Al_xO_y layers, which used in the coatings, were dielectric in nature and the Pt layer was semi-transparent. The optimized multilayer coatings exhibited high solar absorptance α ∼ 0.94 ± 0.01 and low thermal emittance ? ∼ 0.06 ± 0.01 at 82 °C. The Rutherford backscattering spectroscopy (RBS) data of Al_xO_y/Pt/Al_xO_y multilayer absorber indicated the Al_xO_y layers present in the coating were nearly stoichiometry. The scanning electron microscope analysis (SEM) result indicated that the average diameter and inter-particles distance of Pt grains were statistically about 146 ± 0.17 nm and 6-10 ± 0.2 nm respectively.     

Reactive plasma deposited SixCyHz films

Si_xC_yH_z films have been prepared at 200°C by reactive plasma deposition from SiH₄ and CH₄ diluted in helium in a tubular reactor. These films have a ratio s (equal to $\text{Si}\text{(}\text{Si+C}\text{))}$ ranging from 0.2 to 0.8, a refractive index ranging from 1.96 to 2.6 and an optical energy band gap in the range 2.7-2.2 eV. The total quantity of hydrogen in the film is 40% when s=0.5. Infrared analysis shows that these films have large fractions of homonuclear bonds and that this material is best described as a polymer. Mass spectrometric measurements of the gaseous products formed in the SiH₄-CH₄-He plasma have been performed and the results are related to the composition of the deposited layers.     

Core-current-enhanced domain-wall pinning in nanocrystalline Fe/sub 73.5/Cu/sub 1/Nb/sub 3/Si/sub 15.5/B/sub 7/ ribbon

We have studied the influence of surface fields H/sub p/ (generated by either direct or alternating core current) on soft magnetic properties of amorphous and nanocrystalline Fe/sub 73.5/Cu/sub 1/Nb/sub 3/Si/sub 15.5/B/sub 7/ ribbon. While in an amorphous ribbon the coercive field H/sub c/ decreases with H/sub p/, in the same optimally annealed ribbon (H/sub c/=1.3 A/m, M/sub m//spl ap/M/sub s/) H/sub c/ increases with H/sub p/ for all the explored types of H/sub p/ (static and dynamic with different phases with respect to that of the magnetizing field H). The unexpected increase of H/sub c/ in nanocrystalline ribbon is associated with the influence of H/sub p/ on the surface and main (inner) domain structure. Here, we develop a model that takes into account this influence and explains the experimental results.     

Interfacial microstructure of NiSix/HfO2/SiOx/Si gate stacks

Integration of NiSi_x based fully silicided metal gates with HfO₂ high-k gate dielectrics offers promise for further scaling of complementary metal-oxide- semiconductor devices. A combination of high resolution transmission electron microscopy and small probe electron energy loss spectroscopy (EELS) and energy dispersive X-ray analysis has been applied to study interfacial reactions in the undoped gate stack. NiSi was found to be polycrystalline with the grain size decreasing from top to bottom of NiSi_x film. Ni content varies near the NiSi/HfO_x interface whereby both Ni-rich and monosilicide phases were observed. Spatially non-uniform distribution of oxygen along NiSi_x/HfO₂ interface was observed by dark field Scanning Transmission Electron Microscopy and EELS. Interfacial roughness of NiSi_x/HfO_x was found higher than that of poly-Si/HfO₂, likely due to compositional non-uniformity of NiSi_x. No intermixing between Hf, Ni and Si beyond interfacial roughness was observed.