Andrew J. Fleming – författare

Intercellular communication in plants plays a vital role in the co-ordination of processes leading to the formation of a functional organism. The signalling systems must function at a local level to co-ordinate events of cellular differentiation, over long distances to co-ordinate developmental and physiological responses in different parts of the plant, and they must even operate between separate individuals - for example, to control fertilization as part of the evolutionary strategy of a particular species. To cope with the diverse requirements for intercellular signalling, plants have evolved a spectrum of molecular mechanisms, and significant progress has been made over the last few years in our understanding of these processes.

This volume provides an overview of our current understanding of intercellular communication in plants, with an emphasis on those research areas showing significant recent progress and promise. It is directed at researchers and professionals in plant biochemistry, physiology, cell biology and molecular biology.

Flexible mechanical systems experience undesirable vibration in response to environmental and operational forces. Vibrations can limit the accuracy of sensitive instruments or cause significant errors in applications where high-precision positioning is essential so their control is often a necessity.

Piezoelectric transducers have been used in countless applications as sensors and actuators. When traditional passive vibration control techniques won''t do, piezoelectric transducers in conjunction with feedback controllers can suppress vibrations effectively.

This monograph presents recent developments in vibration control systems that employ embedded piezoelectric sensors and actuators. It covers various ways in which active vibration control systems can be designed for piezoelectric laminated structures, high-lighting real-time implementation. The text contains numerous examples and experimental results obtained from laboratory-scale apparatus, with details of how similar setups can be built.

Covering the complete design cycle of nanopositioning systems, this is the first comprehensive text on the topic. The book first introduces concepts associated with nanopositioning stages and outlines their application in such tasks as scanning probe microscopy, nanofabrication, data storage, cell surgery and precision optics. Piezoelectric transducers, employed ubiquitously in nanopositioning applications are then discussed in detail including practical considerations and constraints on transducer response. The reader is then given an overview of the types of nanopositioner before the text turns to the in-depth coverage of mechanical design including flexures, materials, manufacturing techniques, and electronics. This process is illustrated by the example of a high-speed serial-kinematic nanopositioner. Position sensors are then catalogued and described and the text then focuses on control.

Several forms of control are treated: shunt control, feedback control, force feedback control and feedforward control (including an appreciation of iterative learning control). Performance issues are given importance as are problems limiting that performance such as hysteresis and noise which arise in the treatment of control and are then given chapter-length attention in their own right. The reader also learns about cost functions and other issues involved in command shaping, charge drives and electrical considerations. All concepts are demonstrated experimentally including by direct application to atomic force microscope imaging.

Design, Modeling and Control of Nanopositioning Systems will be of interest to researchers in mechatronics generally and in control applied to atomic force microscopy and other nanopositioning applications. Microscope developers and mechanical designers of nanopositioning devices will find the text essential reading.