Early stages of soldering reactions

Early stages of soldering reactions

An experiment on the early stages of intermetallic compound layer growth during soldering and its theoretical analysis were conducted with the intent to study the controlling factors of the process. An experimental technique based on fast dipping and pulling of a copper coupon in liquid solder followed by optical microscopy allowed the authors to study the temporal behavior of the sample on a s...

Classification of Chemical Reactions: Stages of Expertise

In this study we explore the strategies that undergraduate and graduate chemistry students use when engaged in classification tasks involving symbolic and microscopic (particulate) representations of different chemical reactions. We were specifically interested in characterizing the basic features to which students pay attention when classifying chemical reactions at the symbolic and microscopi...

Early stages of homopolymer collapse

Interest in the protein folding problem has motivated a wide range of theoretical and experimental studies of the kinetics of the collapse of flexible homopolymers. In this paper, a phenomenological model is proposed for the kinetics of the early stages of homopolymer collapse following a quench from temperatures above to below the straight theta temperature. In the first stage, nascent droplet...

Selection of suitable reference genes for real-time PCR studies of early developmental stages of sturgeons

In quantitative real-time PCR, the mRNA level can be quantified in relative terms based on the expression ratio of mRNAs of the target gene and an internal reference gene. Since, an internal standard should be expressed at a constant level among different tissues of an organism at all stages of development, and should be unaffected by the experimental treatment, the stability of different refer...

Ersa wave soldering systems