Results 11 - 20 of 86062
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[en] Forming processes of thin-film fluoropolymer coating in the HF discharge reactor on the surface at various technological modes of deposition are considered. The molecular and structural characteristics of the films are studied. Areas of optimum technological modes of producing of nano-sized and thin fluoropolymer films with better electro physical properties are determined. (paper)
[en] Full text: Covalent organic frameworks (COFs) are polymer assemblies with high crystallinity, high porosity and configurable skeletal structure. They have potential applications in filtration, gas storage, and electronic devices among others. However, the realization of these applications requires a high degree of morphological control in their preparation, and permanent high crystallinity – bonds in these frameworks are easily reversed in humid atmospheres. The construction of substrate-confined COF materials that are simultaneously highly crystalline, well-oriented and functional remains a challenge due to insufficient understanding of the basic mechanisms controlling the nucleation and growth of covalent organic frameworks, particularly on a substrate. This knowledge is crucial to further progress the development of more concrete techniques that will ultimately lead to covalent organic frameworks that are crystallographically and structurally well-defined in film form. In this poster, I will describe some of our recent progress towards synthesizing dense, crystalline COF layers. (author)
[en] Growing demand for efficient, high-resolution surface processing has led to the emergence of a rich variety of plasma-based technologies underpinned by an equally wide range of technological setups, each optimized for a specific task, e.g. highly-selective removal of surface layers, precision surface functionalization and nanoscale structuring, or deposition of thin films and nanostructures. However, with increasing device integration and miniaturization, flexible processing technologies capable of delivering complex treatments, such as the growth of complex hierarchical single- and multi-component nanostructures within a single processing environment are highly desired. Yet, such systems are difficult to achieve due to the necessity of the in-process float, and limiting technological capabilities of individual plasma sources and treatment setups. Using a novel flexible platform as an example, this review presents a careful analysis of the physical principles, capabilities and limitations of existing plasma technologies with an ultimate aim to define key principles for the development of prospective flexible platforms for complex plasma-enabled material synthesis and processing. Such a platform would have a significant potential to increase the effectiveness of plasma technology with respect to productivity, material and energy consumption, cost and turnaround time.
[en] The dielectric loss in amorphous, thin-film oxide insulators produces a real part of the ac conductivity σ prime (ω) that scales as ωs with s∼1. Conventional models explain this frequency dependence by hopping or tunneling of charge between neighboring defect sites. These models fail at low temperatures since they predict that σ prime should vanish at T=0. We observe that the ac conductivity of Ta2O5, ZnO, and SiO2 has a nonzero extrapolated value at T=0. We propose that this behavior is consistent with the predictions of a Coulomb glass, an insulator with a random distribution of charged defects. [copyright] 2001 American Institute of Physics
[en] We consider random sequential adsorption on a lattice. We use analytical results on the Bethe lattice and cactus as references to develop systematic perturbationlike expansions which are very rapidly convergent. The latter produces the jamming density of a square lattice with an accuracy within 10-5. This expansion is based on both physical and mathematical considerations and is not restricted to random sequential adsorption
[en] The precessional switching process in magnetic recording thin films is investigated by means of micromagnetic simulations. The uniform mode theory is used to predict the right time instant to switch off the field and the time tolerance which still allows successful switching. This analysis is performed for different values of applied field and anisotropy constant. We verified that the uniform mode theory provides accurate information about the tolerance on the switching time for moderately soft materials
[en] We experimentally demonstrate that metal/oxide/floating-Schottky junction has multiple effective capacitances depending on the amount of electrons stored in the floating metal electrode. The oxide thin film covering the Schottky junction is used to trap electrons in the floating metal. The electron flow into and out of the floating metal is controlled by applying voltage pulses of opposite polarities onto the semiconductor substrate. With the amount of excess charges in the floating metal, the depletion capacitance of Schottky junction varies synchronously, which dominantly affects the effective capacitance of the whole junction. Interestingly, the capacitance of metal/oxide/floating- Schottky junction measured as a function of applied voltage pulse shows a hysteretic behavior, which supports its capacitive memory effect. It is expected that our metal/oxide/floating-Schottky junction can work as a memcapacitor capable of recording multiple switchable capacitance values and it can be readily fabricated with the current Si CMOS technology.
[en] Dye-doped hybrid silicate/titanium nanofilms on the glass substrate structures of asymmetrical waveguides were studied by way of laser systems. The threshold, spatial and spectral features of the laser oscillation of genuine and hollow waveguides were determined. The pattern of stimulated radiation included two concurrent processes: single-mode waveguide lasing and lateral small divergence emission. Comparison of the open angle of the lateral beams and grazing angles of the waveguide lasing mode provides an insight into the effect of leaky mode emission followed by Lummer–Gehrcke interference. (paper)