15,009 research outputs found
Pervasive liquid metal direct writing electronics with roller-ball pen
A roller-ball pen enabled direct writing electronics via room temperature
liquid metal ink was proposed. With the rolling to print mechanism, the
metallic inks were smoothly written on flexible polymer substrate to form
conductive tracks and electronic devices. The contact angle analyzer and
scanning electron microscope were implemented to probe the inner property of
the obtained electronics. An ever high writing resolution with line width and
thickness as 200{\mu}m and 80{\mu}m, respectively was realized. Further, with
the administration of external writing pressure, GaIn24.5 droplets embody
increasing wettability on polymer which demonstrates the pervasive adaptability
of the roller-ball pen electronics
Combinatorial proofs of some properties of tangent and Genocchi numbers
The tangent number is equal to the number of increasing labelled
complete binary trees with vertices. This combinatorial interpretation
immediately proves that is divisible by . However, a stronger
divisibility property is known in the studies of Bernoulli and Genocchi
numbers, namely, the divisibility of by . The
traditional proofs of this fact need significant calculations. In the present
paper, we provide a combinatorial proof of the latter divisibility by using the
hook length formula for trees. Furthermore, our method is extended to -ary
trees, leading to a new generalization of the Genocchi numbers
Structural Change in an Open Economy
We develop a tractable, three-sector model to study structural change in an open
economy. The model features an endogenous pattern of trade dictated by comparative
advantage. We derive an intuitive expression linking sectoral employment shares to
sectoral expenditure shares and to sectoral net export shares of total GDP. Changes in
productivity and in trade barriers affect expenditure and net export shares, and thus,
employment shares, across sectors. We show how these driving forces can generate the "hump" pattern that characterizes the manufacturing employment share as a country
develops, even when manufacturing is the sector with the highest productivity growth.structural transformation, international trade, sectoral labor reallocation
Structural change in an open economy
We develop a tractable, three-sector model to study structural change in a two-country world. The model features an endogenous pattern of trade dictated by comparative advantage. We derive an intuitive expression linking sectoral employment shares to sectoral expenditure shares and to sectoral net export shares of total GDP. Changes in productivity and in trade barriers affect expenditure and net export shares, and thus, employment shares, across sectors. We show how these driving forces can generate the "hump" pattern that characterizes the manufacturing employment share as a country develops, even when manufacturing is the sector with the highest productivity growth.
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