Bøger af Lei Zhou

This book gathers relatively recent and significant topics in the field of ion channel research. Ion channels form the molecular basis for membrane excitability in cells present in the cardiovascular and nervous systems. In many non-excitable cells, ion channels contribute to diverse physiological functions, including the secretion of signaling compounds like hormones and insulin, cell volume regulation, intracellular signaling, especially Ca2+ signaling, etc. Many human diseases have been attributed to abnormal channel functions and defective membrane expression of channel proteins. On the other hand, ion channels are excellent models for studying protein biophysics, especially the allosteric regulation of protein function by miscellaneous stimuli. Therefore, research on ion channels carries significant meaning for the understanding of basic protein biophysics and diverse physiological functions. Such vital information also assists in developing novel and effective treatments for related human diseases. This book provides graduates and scientists in both basic and clinical levels a comprehensive understanding of cutting-edge advances and a useful and stimulating platform for tackling their own questions about ion channels.

In recent years, we have witnessed a rapid expansion of using super-thin metasurfaces to manipulate light or electromagnetic wave in a subwavelength scale. However, most designs are confined to a passive scheme and monofunctional operation, which hinders considerably the promising applications of the metasurfaces. Specifically, the tunable and multifunctional metasurfaces enable to facilitate switchable functionalities and multiple functionalities which are extremely essential and useful for integrated optics and microwaves, well alleviating aforementioned issues. In this book, we introduce our efforts in exploring the physics principles, design approaches, and numerical and experimental demonstrations on the fascinating functionalities realized. We start by introducing in Chapter 2 the "e;merging"e; scheme in constructing multi-functional metadevices, paying particular attention to its shortcomings issues. Having understood the merits and disadvantages of the "e;merging"e; scheme, we then introduce in Chapter 3 another approach to realize bifunctional metadevices under linearly polarized excitations, working in both reflection and transmission geometries or even in the full space. As a step further, we summarizes our efforts in Chapter 4 on making multifunctional devices under circularly polarized excitations, again including designing principles and devices fabrications/characterizations. Starting from Chapter 5, we turn to introduce our efforts on using the "e;active"e; scheme to construct multifunctional metadevices under linearly polarized wave operation. Chapter 6 further concentrates on how to employ the tunable strategy to achieve helicity/frequency controls of the circularly polarized waves in reflection geometry. We finally conclude this book in Chapter 7 by presenting our perspectives on future directions of metasurfaces and metadevices.

Avoiding excessive mathematical calculations, this volume nevertheless provides details on how to extend basic circuit theory to scenarios where currents lack spatial uniformity along the wires. It includes application exemplars and formulae derivation.