Many nature materials have hierarchical structure, and its last cascade is
always on a molecule scale, e. g., double-stranded DNA, making the hierarchy
effective with minimal building blocks. Now ...artificial hierarchy can begin
with a nanoscale level to embody the material with remarkable and
fascinating properties which can be never achieved using non-hierarchical
structure. A strong desire to fabricate some biomimicking hierarchies from a
molecule level has been stimulating scientists. Herein we show that
molecular structure can be easily controlled by a long and narrow tube, and
self-assembly of macromolecules can be achieved to improve its crystallinity
with plenty of excellent properties. We anticipate this paper to be a
starting point for more sophisticated fabrication of fibers with
self-assembly of macromolecules.
nema
Nonlinear oscillator of an artificial bone Wang, Qingli; Shi, Xiangyang
Journal of low frequency noise, vibration, and active control,
12/2019, Letnik:
38, Številka:
3-4
Journal Article
Recenzirano
Odprti dostop
Artificial bone mimicking its living partner has porous structure and should have same fractal dimensions with the bone. This paper studies the transverse vibration of the artificial bones which is ...considered as a porous plate. The result is helpful for designing artificial bones for different uses.
A measuring instrument of the frequency and current dependences of the modulus and phase of the thermal impedance of LEDs and LED matrices of 100 W and higher is described. The principle of operation ...of the measuring instrument is based on the transmission through LEDs of a sequence of impulses of direct current that is pulse-width modulated under the harmonic law, and the determination of the variable component of the temperature of the p–n junction of the LED as the voltage changes during intervals between current impulses. An algorithm is presented to determine the component of full thermal resistance of an LED or an LED matrix from the results of processing the frequency dependences of the modulus and phase of the thermal impedance. Examples of implementation of the algorithm are given.
Decreasing friction force between a swimming suit and water is the key factor
to design swimming suits. Water continuum mechanics forbids discontinuous
fluids, but in angstrom scale water is indeed ...discontinuous. Swimming suit is
smooth on large scale, but it is discontinuous when the scale becomes
smaller. If fractal dimensions of swimming suit and water are the same, a
minimum of friction force is predicted, which means fractal harmonization. In
the paper, fractal harmonic law is introduced to design a swimsuit whose
surface fractal dimensions on a macroscopic scale should be equal to or
closed to the water's fractal dimensions on an Angstrom scale. Various
possible microstructures of fabric are analyzed and a method to obtain
perfect fractal structure of fabric is proposed by spraying nanofibers to its
surface. The fractal harmonic law can be used to design a moving surface with
a minimal friction.
nema
The present communication re-examines the basis of a previous model (E. S. Puchi-Cabrera: Surf. Coat. Technol., 2002, 160, 177 - 186) for the computation of the composite hardness of coated systems ...as a function of the relative indentation depth (RID), applicable to monolayer coatings. The results initially derived from simple geometrical considerations are compared with those obtained taking into account the volumes of the plastic zones of the coating and substrate under the indenter, as proposed by several models already published. A similar expression for the rate of change of the substrate volume fraction with the RID is obtained from both approaches. The consideration of the validity of a linear law of mixtures for the determination of the composite hardness is also reexamined, assuming that the composite hardness could be given by a harmonic law of mixtures. Both the previous model and the one developed from the introduction of a harmonic law of mixtures are extended to deal with multilayer coatings. In this case, the composite hardness as a function of the RID is calculated in terms of the volume fraction and hardness of each of the layer materials which compose the multilayer coating, and also two constants which characterise the behaviour of the coating. The results derived from the new model based on the harmonic law of mixtures are then compared with those obtained from the previous model, employing a number of systems involving both monolayer and multilayer coatings deposited onto different substrates.
Příspěvek, jako pokračování článku Hanzel (2009), poskytuje metodologickou zobecnění Newtonovy metody teorie konstrukce, jak je aplikováno v knize I a knize III jeho Principia. Rekonstruuje také ...metodu opatření uplatňovanou v těchto knihách. Nakonec ukazuje, jak pojem ,,harmonické právo'' mění svůj význam v Principii.
Igor Hanzel
The paper, as a continuation of the paper Hanzel (2009), provides a methodological generalization of Newton’s method of theory construction as applied in Book I and Book III of his Principia. It reconstructs also the method of measures applied in those books. Finally, it shows how the term ''harmonic law'' changes its meaning in the Principia.
The fractal harmonic law admits that the friction between the pure water and the moving surface is the minimum when fractal dimensions of water in Angstrom scale are equal to fractal dimensions of ...the moving surface in micro scale. In the paper, the fractal harmonic law is applied to demonstrate the mechanism of waterproof/ dustproof. The waterproof phenomenon of goose feathers and lotus leaves is illustrated to verify our results and experimental results agree well with our theoretical analysis.
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