[Improving the effectiveness of orthodontic correction in children with malocclusion and musculoskeletal disorders]. / Povyshenie éffektivnosti ortodonticheskoi korrektsii u detei s anomaliiami prikusa i narusheniiami oporno-dvigatel'nogo apparata.

The article discusses the choice of methods and the type of orthodontic equipment for correction of bite anomalies of different degree of severity in children who have concomitant diseases in the form of disorders of the musculoskeletal system (acquired deformities of the spine and feet). To achieve this goal, the use of a decision-making program on the selection of therapeutic and prophylactic measures in children aged 6, 9 and 12 is proposed. The software was developed on the basis of a statistical analysis of the results of the examination and correction of dentoalveolar anomalies, taking into account the severity of the disorders, the age of the patients. The computer program allows you to predict the development of diseases, taking into account the implementation of treatment and prevention activities, as well as provide recommendations on the choice of methods and apparatus for correcting the pathology of bite in children with musculoskeletal disorders.

Harnessing heterogeneous nucleation to control tin orientations in electronic interconnections.

While many aspects of electronics manufacturing are controlled with great precision, the nucleation of tin in solder joints is currently left to chance. This leads to a widely varying melt undercooling and different crystal orientations in each joint, which results in a different resistance to electromigration, thermomechanical fatigue, and other failure modes in each joint. Here we identify a family of nucleants for tin, prove their effectiveness using a novel droplet solidification technique, and demonstrate an approach to incorporate the nucleants into solder joints to control the orientation of the tin nucleation event. With this approach, it is possible to change tin nucleation from a stochastic to a deterministic process, and to generate single-crystal joints with their c-axis orientation tailored to best combat a selected failure mode.

In situ imaging of microstructure formation in electronic interconnections.

The development of microstructure during melting, reactive wetting and solidification of solder pastes on Cu-plated printed circuit boards has been studied by synchrotron radiography. Using Sn-3.0Ag-0.5Cu/Cu and Sn-0.7Cu/Cu as examples, we show that the interfacial Cu6Sn5 layer is present within 0.05 s of wetting, and explore the kinetics of flux void formation at the interface between the liquid and the Cu6Sn5 layer. Quantification of the nucleation locations and anisotropic growth kinetics of primary Cu6Sn5 crystals reveals a competition between the nucleation of Cu6Sn5 in the liquid versus growth of Cu6Sn5 from the existing Cu6Sn5 layer. Direct imaging confirms that the ß-Sn nucleates at/near the Cu6Sn5 layer in Sn-3.0Ag-0.5Cu/Cu joints.