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181.
Li-Piin Sung Joan Jasmin Xiaohong Gu Tinh Nguyen Jonathan W. Martin 《Journal of Coatings Technology and Research》2004,1(4):267-276
Laser scanning confocal microscopy (LSCM) has been used to characterize the changes in film thickness and local surface morphology
of polymer coatings during the UV degradation process. With the noninvasive feature of LSCM, one can obtain thickness information
directly and nondestructively at various exposure times without destroying the specimens or deriving the thickness values
from IR measurement by assuming uniform film ablation. Two acrylic polymer coatings were chosen for the study, and the physical
and chemical changes of the two systems at various exposure times were measured and analyzed. Those measurable physical changes
caused by UV exposure include film ablation, formation of pits and other surface defects, and increases in surface roughness.
It was found in both coatings that changes in measured film thickness by LSCM were not correlated linearly to the predicted
thickness loss using the changes in the CH band obtained by the Fourier Transform Infrared (FTIR) spectroscopy measurements
in the later degradation stages. This result suggested it was not a uniform film ablation process during the UV degradation.
At later stages, where surface deformation became severe, surface roughness and profile information using LSCM were also proven
to be useful for analyzing the surface degradation process
Presented at the 81st Annual Meeting of the Federation of Societies for Coatings Technology, November 13–14, 2004 in Philadelphia,
PA. 相似文献
182.
Sophie Lakard Nadège Morrand-Villeneuve Boris Lakard Guillaume Herlem Bernard Fahys 《Electrochimica acta》2007,53(3):1114-1126
Up to today, several techniques have been used to maintain cells in culture for studying many aspects of cell biology and physiology. More often, cell culture is dependent on proper anchorage of cells to the growth surface. Thus, poly-l-lysine, fibronectin or laminin are the most commonly used substrates. In this study, electrosynthesized biocompatible polymer films are proposed as an alternative to these standard substrates. The electrosynthesized polymers tested were polyethylenimine, polypropylenimine and polypyrrole. Then, the adhesion, proliferation and morphology of rat neuronal cell lines were investigated on these polymer substrates in an attempt to develop new and efficient polymer materials for cell culture. During their growth on the polymers, the evolution of the cell morphology was monitored using both confocal microscopy and immunohistochemistry, leading to the conclusion of a normal development. An estimation of the adhesion and proliferation rates of rat neuronal cell cultures indicated that polyethylenimine and polypropylenimine were the best substrates for culturing olfactory neuronal cells. A method to favour the differentiation of the neuronal cells was also developed since the final aim of this work is to develop a biosensor for odour detection using differentiated neuronal cells as transducers. Consequently, a biosensor was microfabricated using silicon technology. This microsystem allowed us to culture the cells on a silicon wafer and to position the cells on certain parts of the silicon wafer. 相似文献
183.
The characterization of thin, selectively imprinted films of nylon‐6 was performed. Amino acids were used as template molecules. Spin‐cast films were prepared with sizes ranging from 2 μm to 300 nm, depending on the nylon and template concentration in the casting solution. The morphological characteristics of the film surface were examined by atomic force microscopy, and the structure within the films was observed by freeze‐fracture scanning electron microscopy. The film activity was clearly coordinated with the appearance of nanometer‐sized pores both on the surface and within the film. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 2919–2926, 2006 相似文献
184.
185.
《Calphad》2014
Experimental investigations and Gibbs energy modelling of KCl–LiCl–UCl3 system employing CALPHAD method are reported. Gibbs energy modelling of the subsystems KCl–UCl3 and LiCl–UCl3 was carried out primarily using phase diagram data from the literature. For the Gibbs energy modelling of the KCl–LiCl subsystem, new phase boundary data corresponding to four terminal compositions , 0.05, 0.95 and 0.97) obtained through differential thermal analysis data along with thermochemical and phase diagram data from the literature were used. Thermal analysis was also carried out for KCl–LiCl eutectic mixture containing small amounts of UCl3 and ). The liquidus temperatures for these compositions were found to be 637 K and 674 K. Electromotive force data for dilute solutions of UCl3 in the KCl–LiCl eutectic melt, measured in the temperature range 708–833 K in the present work, were found to be in good agreement with the literature data. These data were also used as input for the Gibbs energy modelling of the KCl–LiCl–UCl3 system. In order to improve the quality of the resulting Gibbs energy functions of the quasibinaries and the quasiternary, enthalpies of mixing of the corresponding melts estimated using an empirical correlation based on surrounded-ion model were also used as input. Finally, the generated Gibbs energy functions were used to compute phase equilibria. 相似文献
186.
杨磊 《水资源与水工程学报》2017,28(4):229-234
近年来,斜桩在桥梁、码头、海上钻井平台及大型输电线路塔架基础等工程中得到广泛应用,研究不同倾角斜桩的荷载传递及承载特性实用意义较大。基于ABAQUS软件,考虑桩土接触特性,模拟分析了不同倾角斜桩的承载特性。结果表明:桩身倾角不大于10°时,倾斜角对单桩的极限承载力影响不大,但会在桩身产生一定弯矩以及桩顶产生一定的水平位移;桩身轴力沿桩长方向的衰减速率随桩身倾角的增大而增大;斜桩桩身弯矩主要分布在桩顶下1/2桩长范围内,其最大值的位置不受桩身倾角以及桩顶竖向荷载的影响;斜桩桩身侧摩阻力沿桩长大致呈"S"型分布,其桩顶以下1/6桩长范围内侧摩阻力远远大于直桩。 相似文献
187.
Ahmed A. Busnaina 《The Journal of Adhesion》1995,51(1):167-180
Recent progress in particle capture and rebound and its effect on the adhesion force is reviewed in this paper. Particles rebound when the incident velocity is greater than a characteristic critical velocity. Lower impaction velocity particles experience elastic and plastic deformation. Recent models for particle rebound and capture are discussed and evaluated in terms of their restrictive assumptions and results. Recent experimental data of particle rebound and capture is also discussed, as is the hydrodynamic removal of captured particles. The removal of particles occurs when the applied hydrodynamic removal force overcomes the adhesion force. The effect of adhesion-induced deformation on the removal of particles is introduced and discussed. 相似文献
188.
Yiming Zeng Zhigang Wang Lijun Wan Yanqiao Shi Guanwen Chen Chunli Bai 《应用聚合物科学杂志》2003,88(5):1328-1335
By the use of atomic force microscopy (AFM), formation mechanism of nodular structure in cellulose acetate membranes was systematically investigated. Elementary factors affecting the nodule formation were delineated on the basis of both kinetic and thermodynamic considerations. It was shown that (1) the exact nature of nodular structure is thermodynamic equilibrium glassy state; nodular structure will vanish in the rubbery state; (2) the thermodynamic factor affecting nodule formation is the membrane formation temperature; with the membrane formation temperature decreasing, more chain segments are able to form nodular structures; (3) nodule formation is dependent on the segment rearrangement; variation of the solvent environment is the major kinetic factor affecting the segment rearrangement and nodule formation. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1328–1335, 2003 相似文献
189.
Giuseppe Placidi Danilo Avola Marco Ferrari Daniela Iacoviello Andrea Petracca Valentina Quaresima Matteo Spezialetti 《Computer methods and programs in biomedicine》2014
Background and objective
The degeneration of the balance control system in the elderly and in many pathologies requires measuring the equilibrium conditions very often. In clinical practice, equilibrium control is commonly evaluated by using a force platform (stabilometric platform) in a clinical environment.In this paper, we demonstrate how a simple movement analysis system, based on a 3D video camera and a 3D real time model reconstruction of the human body, can be used to collect information usually recorded by a physical stabilometric platform.Methods
The algorithm used to reconstruct the human body model as a set of spheres is described and discussed. Moreover, experimental measurements and comparisons with data collected by a physical stabilometric platform are also reported. The measurements were collected on a set of 6 healthy subjects to whom a change in equilibrium condition was stimulated by performing an equilibrium task.Results
The experimental results showed that more than 95% of data collected by the proposed method were not significantly different from those collected by the classic platform, thus confirming the usefulness of the proposed system.Conclusions
The proposed virtual balance assessment system can be implemented at low cost (about 500$) and, for this reason, can be considered a home use medical device. On the contrary, astabilometric platform has a cost of about 10,000$ and requires periodical calibration. The proposed system does not require periodical calibration, as is necessary for stabilometric force platforms, and it is easy to use. In future, the proposed system with little integration can be used, besides being an emulator of a stabilometric platform, also to recognize and track, in real time, head, legs, arms and trunk, that is to collect information actually obtained by sophisticated optoelectronic systems. 相似文献190.
Acquisition of the contact force at the instrument tip can enable better performance, e.g. transparency of the haptic feedback in the surgical robot systems. It is, however, difficult to measure the contact force directly due to technical limitations in attaching sensors to the tip of the instruments. This paper proposes a method to estimate the forces by installing the sensors away from the instrument tip. The proposed method employs specially designed mechanical parts of the slave robot, i.e. a slider cover plate for the z-axis translational force along the insertion direction, and docking clamps for the rotational pivot torques around the fulcrum point. Strain gauges are attached to specially designed places with enhancing shapes. The simulation results of the force estimation are presented to confirm the strain concentration area. The proposed method is validated with quantitative experimental results. Calibrated weights are determined upon the comparison of the strain value with a calibrated 6-axis force/torque sensor. The percentage error in the force calibration is about 5~8% calculated by the root mean square error (RMSE) of force-sensing performance. In addition, it can be computed by considering only the bending phase of each sensor although the hysteresis is observed from the calibration graph. 相似文献