共查询到20条相似文献,搜索用时 15 毫秒
1.
Wenjuan Yao Cuiping Guo Xuemei Luo 《Journal of materials science. Materials in medicine》2013,24(2):515-522
Numerical simulation method was used in this paper to study the effects of partial ossicular replacement prostheses (PORPs) with different materials on hearing restoration, from the biomechanical point of view. According to the CT scan imagery of the right ear from a normal human body, the CT data was digitalized and imported into PATRAN to establish a three dimension finite element model by self-compiling program, and then a frequency response analysis was made for the model. The calculated results were compared with experiment data to verify the correctness of the numerical model. Based on this, human numerical model of PORPs was established to make dynamic calculation of sound conduction and analyse the effects of PORPs with different materials on hearing restoration. The following conclusions are obtained : From the angle of dynamical behaviors in sound conduction process of human ear, in different frequency bands of the same sound pressure, PORPs with different materials have different effects on hearing restoration. A better sound transmission in low frequencies is obtained by PORPs with hydroxyapatite ceramics, stainless steel. In high frequencies, better sound transmission is gained by PORPs with porous polyethylene. In the 500–3,000 Hz range which is clinicians typically measure and pay attention to, better sound transmission is gained by PORPs with alumina ceramics, hydroxyapatite ceramics, EH composite materials and porous polyethylene. There are three materials which has an obvious potential to provide more hearing restoration than another between 500 and 3,000 Hz. The hearing restoration value of hydroxyapatite ceramics is 7.1 dB larger than that of stainless steel. The hearing restoration value of titanium is 4.9 dB larger than that of stainless steel. Hydroxyapatite ceramics has better effects on sound transmission than titanium and other materials. 相似文献
2.
3.
《Advanced Powder Technology》2007,18(5):489-501
To realize a highly efficient anaerobic treatment, it is necessary to immobilize high concentrations of methanogens within a fermenter. In this study, we experimentally examine the effect of the surface characteristics of the acetate-utilizing methanogen Methanosarcina barkeri (JCM 10043) on immobilization to support materials. To this aim, we measured the electrostatic and hydrophobic properties of M. barkeri. The electrophoretic mobility of M. barkeri decreased with increasing ionic strength of the cell suspension and was fitted by the Ohshima equation using two parameters: spatial charge density in the polyelectrolyte region (ZeN = –1.15 × 106 C/m3) and the softness parameter (1/λ = 3.35 × 10−9 m). M. barkeri showed an affinity to n-hexadecane, with adhesion of more than 60%. M. barkeri showed hydrophobicity relative to Escherichia coli. We also carried out a microbial adhesion test to support materials. M. barkeri showed better adhesion to the anion-exchange resin than to the hydrophobic resin. The microbial cells adhered uniformly to the anion-exchange resin, while coagulated cells adhered non-uniformly to the hydrophobic resin. M. barkeri showed poor adhesion to the cation-exchange resin. The anion-exchange resin is most effective in immobilizing M. barkeri within the fermenter. 相似文献
4.
Abdollahi A Jiang Z Arabshahi SA 《IEEE transactions on ultrasonics, ferroelectrics, and frequency control》2007,54(12):2446-2455
The mass sensitivity of the piezoelectric surface acoustic wave (SAW) sensors is an important factor in the selection of the best gravimetric sensors for different applications. To determine this value without facing the practical problems and the long theoretical calculation time, we have shown that the mass sensitivity of SAW sensors can be calculated by a simple three-dimensional (3-D) finite-element analysis (FEA) using a commercial finite-element platform. The FEA data are used to calculate the wave propagation speed, surface particle displacements, and wave energy distribution on different cuts of various piezoelectric materials. The results are used to provide a simple method for evaluation of their mass sensitivities. Meanwhile, to calculate more accurate results from FEA data, surface and bulk wave reflection problems are considered in the analyses. In this research, different cuts of lithium niobate, quartz, lithium tantalate, and langasite piezoelectric materials are applied to investigate their acoustic wave properties. Our analyses results for these materials have a good agreement with other researchers' results. Also, the mass sensitivity value for the novel cut of langasite was calculated through these analyses. It was found that its mass sensitivity is higher than that of the conventional Rayleigh mode quartz sensor. 相似文献
5.
6.
V. I. Sagadeev 《Journal of Engineering Physics and Thermophysics》1990,58(2):200-202
A method is suggested for determining the monochromatic reflectance of a multicomponent inorganic material with an optically smooth surface on the basis of its mineralogical and chemical composition.Translated from Inzhenerno-Fizicheski Zhurnal, Vol. 58, No. 2, pp. 261–264, February, 1990. 相似文献
7.
支承刚度对自动变速器齿轮副的啮合质量有着重要影响,研究支承刚度及齿面涂层对斜齿轮副啮合特性的影响具有重要意义。以某七挡双离合自动变速器的一挡斜齿轮副为研究对象,建立了2种不同支承刚度的齿轴系统刚柔耦合模型,分析了不同工况下支承刚度对斜齿轮副啮合特性的影响规律;通过FCL-250H齿轮精测试验台得到有/无磷酸锰转化涂层齿轮的齿形齿向参数,并将其代入有限元模型进行仿真分析;进行齿轮接触疲劳点蚀实验,对比齿面涂层处理前后齿轮的接触疲劳寿命,并从齿轮表面形貌、动力性能及跑合性能等角度进一步揭示了涂层的强化机理。研究结果表明:齿轴跨度增大,支承刚度减小,则齿轮单位长度所受最大载荷和啮合错位量对输入扭矩的变化更为敏感;有涂层齿轮跑合后更有利于啮合,其疲劳寿命得到提高。研究结果为汽车自动变速器齿轮传动系统的结构优化和齿轮疲劳寿命的提高提供了参考。 相似文献
8.
9.
10.
A thorough analysis is given of a process which is of great importance for the formation of many present day glass ceramic materials: sinter-crystallization. In the first part of the paper the problems determining surface induced nucleation of glasses are analyzed, emphasis being given to the influence of elastic strains and surface contamination by active substrates. The second stage of the analysis is centred on the dependence of crystal growth and overall crystallization kinetics on the mean size of an ensemble of sintering glass grains. Here a formalism is derived, connecting overall crystallization with the mean size of the crystallizing system of glass particles. In the third part the interdependence sintering – crystallization is investigated. Several cases of this interrelation are analyzed in details for different mechanisms of growth of nuclei, athermally formed on the grain surface. 相似文献
11.
12.
《Current Opinion in Solid State & Materials Science》2014,18(6):301-307
Designing electrodes for neural interfacing applications requires deep consideration of a multitude of materials factors. These factors include, but are not limited to, the stiffness, biocompatibility, biostability, dielectric, and conductivity properties of the materials involved. The combination of materials properties chosen not only determines the ability of the device to perform its intended function, but also the extent to which the body reacts to the presence of the device after implantation. Advances in the field of materials science continue to yield new and improved materials with properties well-suited for neural applications. Although many of these materials have been well-established for non-biological applications, their use in medical devices is still relatively novel. The intention of this review is to outline new material advances for neural electrode arrays, in particular those that interface with the surface of the nervous tissue, as well as to propose future directions for neural surface electrode development. 相似文献
13.
14.
C Manohar 《Bulletin of Materials Science》1994,17(7):1299-1306
This paper mostly describes the research on surfactant solutions performed at this centre in the past few years. A correlation
between microemulsion structure and precipitation reaction of AgCl is described. Experimental and theoretical research culminating
in the development of a theme for analysing the structure of colloidal systems is described. Recent results on the discovery
of new viscoelastic surfactant systems are presented. 相似文献
15.
Nine non-metallic friction material formulations contained fibers, fillers and binder without strong abrasives were designed using Golden Section sequence combined with least-square method. Seven ingredients used without strong abrasives were selected based on the combinatorial approach. Wear (w) and coefficient of friction (μ) are expressed as a function of volume fraction of the ingredients selected as and . The formulations were optimized using the sensitivity series obtained from least-square method. An optimized formulation (S-10) was obtained with a total wear loss of 6.69 wt% and an average μ of 0.375. Friction surface of both brake pad and disc was observed using SEM, EDX and XRD. The non-metallic friction materials without abrasives exhibit unique friction performance and phenomena compared with the non-metallic friction materials with abrasives and semi-metallic brake linings. The temperature measured during friction is lower and the oxidation of the cast iron disc is not rigorous. 相似文献
16.
Influence of atmospheric pressure plasma treatment on various fibrous materials: Performance properties and surface adhesion analysis 总被引:1,自引:0,他引:1
Atmospheric pressure plasma treatment using oxygen gas was applied to wool fibrous materials. The plasma-treated fibrous materials were characterised using advanced instrumental techniques including scanning electron microscopy and X-ray photoelectron spectroscopy. They were also tested for performance properties including tensile and tearing strength as well as change in yellowness using international standard testing methods. Wettability analysis was conducted to study the surface area and surface energy of the plasma-treated fibrous materials. Surface modification regarding the enhancement of their adhesion to other substance, i.e. microcapsule treatment, was investigated. 相似文献
17.
《Vacuum》2011,85(12):1466-1470
Atmospheric pressure plasma treatment using oxygen gas was applied to wool fibrous materials. The plasma-treated fibrous materials were characterised using advanced instrumental techniques including scanning electron microscopy and X-ray photoelectron spectroscopy. They were also tested for performance properties including tensile and tearing strength as well as change in yellowness using international standard testing methods. Wettability analysis was conducted to study the surface area and surface energy of the plasma-treated fibrous materials. Surface modification regarding the enhancement of their adhesion to other substance, i.e. microcapsule treatment, was investigated. 相似文献
18.
The present study is aimed at filling the gaps in scientific understanding of the burnishing process, and also to aid and arrive at technological solutions for the surface modifications based on Burnishing of some of the commonly employed engineering materials. The effects of various burnishing parameters on the surface characteristics, surface microstructure, micro hardness are evaluated, reported and discussed in the case of EN Series steels (EN 8, EN 24 and EN 31), Aluminum alloy (AA6061) and Alpha-beta brass. The burnishing parameters considered for studies principally are burnishing speed, burnishing force, burnishing feed and number of passes. Taguchi technique is employed in the present investigation to identify the most influencing parameters on surface roughness. Effort is also made to identify the optimal burnishing parameters and the factors for scientific basis of such optimization. Finally, a brief attempt is made to construct the Burnishing maps with respect to strength level (in this case, average micro hardness of unburnished material). 相似文献
19.
E. A. Artyukhin A. V. Nenarokomov 《Journal of Engineering Physics and Thermophysics》1985,49(4):1173-1177
The authors analyze the possible identification of the functional parameters in the energy balance equation on the disintegrating surface of a solid.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 49, No. 4, pp. 592–598, October, 1985. 相似文献
20.
The development of nanostructured materials offers new scientific and technological perspectives due to the specific interesting physical properties of these materials. These properties derive either from their reduced grain size or from the structure and properties of the grain boundaries, which constitute a significant volume fraction. Mechanical alloying, widely used to produce dispersion-strengthened and amorphous alloys, has been employed in recent years to synthesize nanocrystalline metallic, semiconductors, and covalent component-based materials. Based on statistical analysis of transmission and scanning electron microscopic images, the distribution and spatial repartition of the nanostructural material prepared by mechanical alloying and/or attrition are presented for some specific cases. 相似文献