A numerical method to analyse the influence of assembly error on spur gear tooth contact load distribution considering bearing elasticity is formulated. In the proposed approach, a set of transformation matrices are used to define the deviation in tooth geometry orientation from the ideal position due to the bearing elasticity and assembly error. To calculate the gear tooth deflection, the theory of contact mechanics is applied to determine the micro deformation field at the surface layer of the contact region, while the finite element model is used to represent the bulk deformation in the rest of the gear structure. An efficient search strategy for obtaining the true contact points of the deformed tooth is employed. In this strategy, the tooth contact load distribution is determined based on the smallest distance between each pair of candidate contact points within a cross-section of the mating teeth, and as well as the corresponding force and moment balance conditions. Finally, the proposed model is applied to analyse the effect of assembly errors defined at eight circumferential positions on the tooth deformation in a geared rotor system comprising of four elastic bearings.
In this work, the initial growth process of a polypyrrole/oligonucleotide (PPy/ODN) nanocomposite electrochemically synthesized on an indium tin oxide (ITO)-coated glass surface was investigated by means of chronoamperometric measurements combined with optical microscopy and atomic force microscopy (AFM). It was found that the growth of PPy/ODN onto ITO was a three-stage process including incubation, rapid nucleation and growth, and constant nucleation and growth. The presence of ODN molecules significantly shortened the first stage. Further analysis showed that the nucleation and growth mechanism of PPy/ODN was progressive nucleation and 3D growth, which then changed to instantaneous nucleation and 3D growth before nucleus overlapping. In the third stage, the nucleation and growth mechanism of PPy/ODN was a combination of progressive nucleation and 3D growth and instantaneous nucleation and 3D growth.
In this paper, some factors governing the evaporation rate of aqueous microdroplets generated in a newly developed PDMS (polydimethylsiloxane) microchannel device were examined. Microdroplets of about 0.25 nL, composed of any one of the conventional solvents (including water, ethanol, and hexane) were found to be disappearing in about 1 h in a PDMS microchannel (diameter 80 mm) when exposed to heating under light microscopy, although this slightly slowed down when placed in an ambient environment. Furthermore, when the inner wall of the PDMS microchannel was microfluidic coated by phospholipid solution, aqueous microdroplets could be maintained with no volume-loss up to at least 1 h.
This paper presents evidence and some preliminary explanation for the existence of a steric effect in polypyrrole/oligonucleotide (PPy/ODN) nanocomposite film, which may be responsible for the high electrochemical sensing performance of that nanofilm when being used in DNA hybridization detection. When hybridization occurs in this nanocomposite film, the steric effect in the immediate interface of the hybrid film can damp the ion-flux penetrating through this interface, thus resulting in the signal differentiation on the electrode electrochemical property. Electrochemical cyclic voltammetry (CV) combined with atomic force microscope (AFM) were utilized to clarify the hindering mechanism occurring on such interface. Furthermore, the hybridization reaction of ODN probes in the hybrid PPy/ODN film with their complementary DNA sequences was measured via CV, with the target ODN concentrations as low as 5310 218 mol/L. Under optimized hybridization conditions the sensor response was almost linear, with the logarithm of the target ODN concentration ranging from 1310 218 to 1310 211 mol/L. These results may be useful in the development of a much simpler labelfree DNA sensor based on the PPy/ODN nanocomposite film.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.