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991.
Ana Santos‐Coquillat Enrique Martínez‐Campos Nelson Vargas‐Alfredo Raúl Arrabal Juan Rodríguez‐Hernndez Endzhe Matykina 《Macromolecular bioscience》2019,19(10)
Magnesium‐based implants present several advantages for clinical applications, in particular due to their biocompatibility and degradability. However, degradation products can affect negatively the cell activity. In this work, a combined coating strategy to control the implant degradation and cell regulation processes is evaluated, including plasma electrolytic oxidation (PEO) that produces a 13 µm‐thick Ca, P, and Si containing ceramic coating with surface porosity, and breath figures (BF) approach that produces a porous polymeric poly(ε‐caprolactone) surface. The degradation of PCL‐PEO‐coated Mg hierarchical scaffold can be tailored to promote cell adhesion and proliferation into the porous structure. As a result, cell culture can colonize the inner PEO‐ceramic coating structure where higher amount of bioelements are present. The Mg/PEO/PCL/BF scaffolds exhibit equally good or better premyoblast cell adhesion and proliferation compared with Ti CP control. The biological behavior of this new hierarchical functionalized scaffold can improve the implantation success in bone and cardiovascular clinical applications. 相似文献
992.
Achraf El Kasmi Henning Vieker Ling-nan Wu André Beyer Tarik Chafik Zhen-yu Tian 《化学物理学报(中文版)》2019,32(3):365-372
Thin cuprous oxide films have been prepared by chemical vapor deposition (pulsed spray evaporation-chemical vapor deposition) method without post-treatment. The synthesis ofcuprous oxide was produced by applying a water strategy effect. Then, the effect of water on the morphology, topology, structure, optical properties and surface composition of the obtained films has been comprehensively investigated. The results reveal that a pure phase of Cu2O was obtained. The introduction of a small quantity of water in the liquid feedstock lowers the band gap energy from 2.16 eV to 2.04 eV. This finding was mainly related to the decrease of crystallite size due to the effect of water. The topology analyses, by using atomic force microscope, also revealed that surface roughness decreases with water addition, namely more uniform covered surface. Moreover, theoretical calculations based on density functional theory method were performed to understand the adsorption and reaction behaviors of water and ethanol on the Cu2O thin film surface. Formation mechanism of the Cu2O thin film was also suggested and discussed. 相似文献
993.
A theoretical study predicts that surface-plasmon-polariton (SPP) waves may propagate along the interface of a columnar thin film (CTF) and a metal over a range of propagation directions relative to the morphology of the CTF. The range of propagation directions depends on the tilt of the columns in the CTF. The phase speed of the SPP wave varies mainly as a function of the tilt of the CTF columns. Both the confinement of the SPP wave to the interface and the decay of the SPP wave along the direction of propagation depend strongly on the direction of propagation relative to the morphologically significant plane of the CTF. The greater the columnar tilt in relation to the interface, the shorter is the range of propagation. Because of CTF porosity and the ability to engineer this biaxial dielectric material, the CTF–metal interface may be more attractive for sensor applications than the traditional dielectric–metal interface used for SPP-wave-based sensors. 相似文献
994.
Ferydon Babaei 《Optics Communications》2008,281(11):3120-3130
The transmission and reflection spectra from a right-handed chiral sculptured zirconia thin film are calculated using the piecewise homogeneity approximation method and the Bruggeman homogenization formalism using both dispersive and non-dispersive functions for axial and non-axial states. The comparison of spectral results shows that the dispersion of the dielectric function has a considerable effect on the results. In axial excitation of cross-polarized reflectances and co-polarized transmittances the dispersion effect becomes more pronounced at wavelengths further away from the homogenization wavelength. This is also true in the case of non-axial excitation of circular transmittances, while there are considerable differences for cross-polarized reflectances where (wavelength) the first Bragg peak occurs. At wavelengths in the vicinity of the homogenization wavelength the dispersion effect of the dielectric function in RRR becomes more significant. 相似文献
995.
Qiuyuan Feng Tingju Li Hongyun Yue Kai Qi Fudong Bai Junze Jin 《Applied Surface Science》2008,254(8):2262-2268
Ni-Al2O3 composite coatings were prepared by using sediment co-deposition (SCD) technique and conventional electroplating (CEP) technique from Watt's type electrolyte without any additives. The microstructure, hardness, and wear resistance of resulting composites were investigated. The results show that the incorporation of nano-Al2O3 particles changes the surface morphology of nickel matrix. The preferential orientation is modified from (2 0 0) plane to (1 1 1) plane. The microhardness of Ni-Al2O3 composite coatings in the SCD technique are higher than that of the CEP technique and pure Ni coating and increase with the increasing of the nano-Al2O3 particles concentration in plating solution. The wear rate of the Ni-Al2O3 composite coating fabricated via SCD technique with 10 g/l nano-Al2O3 particles in plating bath is approximately one order of magnitude lower than that of pure Ni coating. Wear resistance for SCD obtained composite coatings is superior to that obtained by the CEP technique. The wear mechanism of pure Ni and nickel nano-Al2O3 composite coatings are adhesive wear and abrasive wear, respectively. 相似文献
996.
在常重力下模拟微重力燃烧对载人航天器的火灾安全具有重要意义.窄通道就是这样一种可以有效限制自然对流的模拟设施.但是,不同重力下火焰传播的相似性仍然是有待研究的问题.本文用实验和数值模拟的方法,比较了不同重力下有限空间内热薄材料表面的逆风传播火焰.不同重力下火焰形状和火焰传播速度的比较表明,1cm高的水平窄通道可以有效地限制自然对流,在常重力下用这种通道能够模拟微重力下相同几何尺寸的通道中的火焰传播.因此,在地面上首先利用水平窄通道,模拟相同环境中的微重力火焰传播,然后考虑通道尺寸变化对火焰传播的影响,有可能成为地面模拟其他尺寸的空间中的微重力燃烧的方法. 相似文献
997.
Luminescence spectra and photoluminescence excitation spectra of Y2O3:Bi and Y3Al5O12:Bi thin films were investigated. Luminescence was stimulated by the emission from two types of centers that were associated
with the substitution of Bi3+ for Y3+ in sites of the crystal lattice of Y2O3 (Y3Al5O12) with point symmetries C2 and C3i (D2 and C3i). The emission of Bi3+ in the site with point symmetry C3i causes blue luminescence in both Y2O3:Bi and Y3Al5O12:Bi films with maxima at 3.03 eV and 3.15 eV, respectively, that is related to the 3P1-1S0 transition. The emission of Bi3+ in the site with point symmetry C2 gives green luminescence in Y2O3:Bi with the maximum at 2.40 eV that is also related to the 3P1-1S0 transition. The emission of Bi3+ in the site with point symmetry D2 leads to ultraviolet luminescence in Y3Al5O12:Bi with the maximum at 3.75 eV that corresponds to the 3P1-1S0 transition. The red luminescence band with the maximum at 1.85 eV in Y2O3:Bi is due to the presence of structural defects.
__________
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 75, No. 2, pp. 202–207, March–April, 2008. 相似文献
998.
X-ray photoelectron spectroscopy (XPS) was used to characterise the effects of low energy (<2 eV) argon ion plasma surface modification of TiO2 thin films deposited by radio frequency (RF) magnetron sputter system. The low energy argon ion plasma surface modification of TiO2 in a two-stage hybrid system had increased the proportion of surface states of TiO2 as Ti3+. The proportion of carbon atoms as alcohol/ether (COX) was decreased with increase the RF power and carbon atoms as carbonyl (CO) functionality had increased for low RF power treatment. The proportion of C(O)OX functionality at the surface was decreased at low power and further increase in power has showed an increase in its relive proportion at the surface. The growth of S180 cells was observed and it seems that cells are uniformly spreads on tissue culture polystyrene surface and untreated TiO2 surfaces whereas small-localised cell free area can be seen on plasma treated TiO2 surfaces which may be due to decrease in C(O)OX, increase in CO and active sites at the surface. A relatively large variation in the surface functionalities with no change in the surface roughness was achieved by different RF plasma treatments of TiO2 surface whereas no significant change in S180 cell growth with different plasma treatments. This may be because cell growth on TiO2 was mainly influenced by nano-surface characteristics of oxide films rather than surface chemistry. 相似文献
999.
The aim of this work is to discuss the growth characteristics of the ceramic coatings on Ti alloy by plasma electrolytic oxidation (PEO) technique. Ceramic coatings were prepared on Ti alloy by plasma electrolytic oxidation in different electrolyte solutions under different pulse modes. The composition and the structure of the coatings were investigated by X-ray diffraction and scanning electron microscopy (SEM), respectively. The amount of the dissolved titanium into the electrolytes during PEO process was measured by inductively coupled plasma-atomic emission spectrometer (ICP-AES). The structure and the composition of the coatings were related to the mode of the spark discharge during PEO process. (a) Under the pulsed single-polar mode: In Na3PO4 solution, the spark discharge was mainly due to the breakdown of the oxide film, and the coatings prepared were porous and mainly structured by the Ti from the substrate. In K4ZrF6-H3PO4 and NaAlO2-Na3PO4 solutions, the main mode of the spark discharge was the breakdown of the oxide film at the initial stage, and then changed into the breakdown of the vapor envelope, and the coatings were rough and thick, and mainly structured by the elements from the electrolyte. (b) Under the pulsed bi-polar mode in NaAlO2-Na3PO4 solution, the spark discharge may be mainly due to the breakdown of the oxide film, the coatings prepared were dense in inner layer and loose in outer layer, and structured by the elements from both the substrate and the electrolyte. Besides, the ICP-AES analyses showed that the amount of the dissolved titanium in the electrolyte during PEO process was more under the breakdown of the oxide film than under the breakdown of the vapor envelope, which was consistent with the changes of the structure of the coatings. Cathode pulse in the pulsed bi-polar mode increased the amount of the dissolved titanium in the electrolyte, compared with the pulsed single-polar one. 相似文献
1000.
Effect of annealing on the properties of N-doped ZnO films deposited by RF magnetron sputtering 总被引:1,自引:0,他引:1
Jinzhong Wang Elangovan Elamurugu François Jomard Ana M. Botelho do Rego Gonçalo Gonçalves Elvira Fortunato 《Applied Surface Science》2008,254(22):7178-7182
N-doped ZnO films were deposited by RF magnetron sputtering in N2/Ar gas mixture and were post-annealed at different temperatures (Ta) ranging from 400 to 800 °C in O2 gas at atmospheric pressure. The as-deposited and post-annealed films were characterized by their structural (XRD), compositional (SIMS, XPS), optical (UV-vis-NIR spectrometry), electrical (Hall measurements), and optoelectronic properties (PL spectra). The XRD results authenticate the improvement of crystallinity following post-annealing. The weak intensity of the (0 0 2) reflection obtained for the as-deposited N-doped ZnO films was increased with the increasing Ta to become the preferred orientation at higher Ta (800 °C). The amount of N-concentration and the chemical states of N element in ZnO films were changed with the Ta, especially above 400 °C. The average visible transmittance (400-800 nm) of the as-deposited films (26%) was increased with the increasing Ta to reach a maximum of 75% at 600 °C but then decreased. In the PL spectra, A0X emission at 3.321 eV was observed for Ta = 400 °C besides the main D0X emission. The intensity of the A0X emission was decreased with the increasing Ta whereas D0X emission became sharper and more optical emission centers were observed when Ta is increased above 400 °C. 相似文献