DLC/TiNi microcage for biopsy applications

A TiNi/diamond-like-carbon (DLC) microcage for biological application has been designed, fabricated and characterized. A compressively stressed DLC film with TiNi pattern on top lifts the fingers upwards once they are released from the substrate, and the microcage can be closed through shape memory effect of top TiNi film with temperature below 80°C. Further heating above 100°C, the gradual opening of the microcage can be obtained due to thermal bimorph effect. The biocompatibility of both the TiNi and DLC films has been proved using a cell-culture method.

Density, sp3 content and internal layering of DLC films by X-ray reflectivity and electron energy loss spectroscopy

A variety of hydrogenated and non-hydrogenated amorphous carbon thin films have been characterized by means of grazing-incidence X-ray reflectivity (XRR) to give information about their density, thickness, surface roughness and layering. We used XRR to validate the density of ta-C, ta-C:H and a-C:H films derived from the valence plasmon in electron energy loss spectroscopy measurements, up to 3.26 and 2.39 g/cm3 for ta-C and ta-C:H, respectively. By comparing XRR and electron energy loss spectroscopy (EELS) data, we have been able for the first time to fit a common electron effective mass of m*/me = 0.87 for all amorphous carbons and diamond, validating the `quasi-free' electron approach to density from valence plasmon energy. While hydrogenated films are found to be substantially uniform in density across the film, ta-C films grown by the filtered cathodic vacuum arc (FCVA) show a multilayer structure. However, ta-C films grown with an S-bend filter show a high uniformity and only a slight dependence on the substrate bias of both sp3 and layering.

Laser micromachining of sputtered DLC films

DLC films with different thicknesses (from 100 nm to 1.9 μm) were deposited using sputtering of graphite target in pure argon atmosphere without substrate heating. Film microstructures (sp2/sp3 ratio) and mechanical properties (modulus, hardness, stress) were characterized as a function of film thickness. A thin layer of aluminum about 60 nm was deposited on the DLC film surface. Laser micromachining of Al/DLC layer was performed to form microcantilever structures, which were released using a reactive ion etching system with SF6 plasma. Due to the intrinsic stress in DLC films and bimorph Al/DLC structure, the microcantilevers bent up with different curvatures. For DLC film of 100 nm thick, the cantilever even formed microtubes. The relationship between the bimorph beam bending and DLC film properties (such as stress, modulus, etc.) were discussed in details. © 2005 Elsevier B.V. All rights reserved.

PEO陶瓷层对铝基体上DLC薄膜承载特性的影响

重载作用下,类金刚石(DLC)薄膜直接应用于铝合金等软金属基体上易发生脆性破裂和剥离而导致过早失效.针对这一问题,以PEO陶瓷层作为承载层,采用有限元数值计算方法,对复合涂层在均布接触载荷作用下的应力场进行研究.结果表明:陶瓷层可明显降低DLC膜的表面拉应力和界面剪应力,起到了良好的载荷支撑作用;陶瓷层厚度对涂层表面拉应力,界面及基体内剪应力的分布有显著影响,其中陶瓷层厚度与接触半宽比为0.150.30时,涂层可以获得较为合理的表面和界面应力场,从而改善DLC膜在铝合金基体上的摩擦磨损性能

Primera carta pastoral que, en Chiapas, expide el Illmo. Sr. Obispo Dor. D. fr. Ramón María de San José Moreno y Castañeda, adoptando la del Illmo. Sor. Obispo de Querétaro, sobre el predominante vicio de la usura

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Carta pastoral en que el ilustrísimo Señor Arzobispo de México hace suya la del Ilmo. Sr. Obispo de Querétaro sobre la usura

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Tratado de la usura, en tres libros

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Optical and electrical properties of polymerizing plasmas and their correlation with DLC film properties

Diamond-like carbon (DLC) films were grown from radiofrequency plasmas of acetylene-argon mixtures, at different excitation powers, P. The effects of this parameter on the plasma potential, electron density, electron temperature, and plasma activity were investigated using a Langmuir probe. The mean electron temperature increased from about 0.5 to about 7.0 eV while the mean electron density decreased from about 1.2x10(9) to about 0.2x10(9) cm(-3) as P was increased from 25 to 150 W. Both the plasma potential and the plasma activity were found to increase with increasing P. Through actinometric optical emission spectrometry, the relative concentrations of CH, [CH], and H, [H], in the discharge were mapped as a function of the applied power. A rise in [H] and a fall in [CH] with increasing P were observed and are discussed in relation to the plasma characteristics and the subimplantation model. The optical properties of the films were calculated from ultraviolet-visible spectroscopic data; the surface resistivity was measured by the two-point probe method. The optical gap, E(G), and the surface resistivity, rho(s), fall with increasing P. E(G) and rho(s) are in the ranges of about 2.0-1.3 eV and 10(14)-10(16) Omega/square, respectively. The plasma power also influences the film self-bias, V(b), via a linear dependence, and the effect of V(b) on ion bombardment during growth is addressed together with variation in the relative densities of sp(2) and sp(3) bonds in the films as determined by Raman spectroscopy.

Properties of DLC films deposited by an oxyacetylene flame

Diamond-like carbon (DLC) films were obtained by spinning a tungsten carbide substrate at a high speed using an oxyacetylene flame. The films deposited at a typical experimental condition of substrate temperature of 810 degrees C, rotation of 600 rpm and 3 h deposition time, exhibited an uniform, very smooth, hard and glassy surface covering the entire exposed face of the substrate. These films were identified as DLC by their characteristic broad Raman spectra centered at 1554 cm(-1) and micro-Vicker's hardness > 3400 kg mm(-2). For substrate temperatures < 800 degrees C the film started losing the uniform glassy surface and the hardness deteriorated. For temperatures > 950 degrees C the film was still hard and shiny, but black in color. DLC films were also obtained in a wide range of speeds of rotation (300-750 rpm), as long as the temperature remained close to 850 degrees C. (C) 1999 Elsevier B.V. S.A. All rights reserved.