In earlier papers the second author and Charles Read have introduced and studied a new notion of positivity for operator algebras, with an eye to extending certain C * -algebraic results and theories to more general algebras. The present paper consists of complements to some facts in the just mentioned papers, concerning this notion of positivity. For example we prove a result on the numerical range of products of the roots of commuting operators with numerical range in a sector.

A transistor that can be stretchable biaxially is a basic and indispensable component for many emerging applications ranging from wearables to organ implants and to soft robotics. A general approach to enable mechanical stretchability in transistors from existing non-stretchable materials is to create certain mechanical architectures such as in-plane serpentines, out-of-plane wavy structures, kirigami structures, and the hybridization of elastic interconnectors and rigid components. Different from general stretchable transistors, we report the development of elastic transistors based on rubbery semiconductors nanocomposite of poly(3-hexylthiophene-2,5-diyl) nanofibrils percolated in silicone rubber matrix. The transistor is fully with elastic materials and manufactured all by solution process. The transistor exhibits a field-effect mobility of 3.3 cm 2 /V•s.The elastic transistor can be stretched biaxially with 50% linear strain and 125% areal strain and it retains its electrical performances. The exhibited reliable electrical functions upon mechanically poked or expanded as a skin for pneumatically actuated soft robots illustrate some practical applications of such biaxially stretchable transistors.

In article number 1800043, Cunjiang Yu and co-workers develope fully elastic stretchable transistors. The transistors are fabricated based on a solution process and can be stretched bi-axially with 125% areal strain while retaining stable operation and device characteristics. This Frontispiece illustrates the rubbery semiconductor from polythiophene nanofibrils in a percolated fashion and the transistor array in a deformed format.

This paper is a continuation of the program started by Ruan in [11] and [12], of developing real operator space theory. In particular, we develop the theory of real operator algebras. We also show among other things that the injective envelope, C * -envelope and non-commutative Shilov boundary exist for a real operator space. We develop real one-sided M -ideal theory and characterize one-sided M -ideals in real C * -algebras and real operator algebras with contractive approximate identity.

No abstract