Devices historical background

B. Experimental Determination of Detonation Velocity. Historical background for development of methods for exptl determination of deton velocities is already given in Vol 3 of this Encycl (Ref 75), pp C310-R and C311-L, under Chronographs and Other Devices Used for Measuring Detonation Velocities of Explosives. 

Scaling of the variables also has an historical background. In the past, (B.C. before computers), all calculations had to be carried out by hand or by mechanical devices. Least squares fitting of models was a cumbersome process with the natural variables, and more easily done with scaled variables. Natural variables would also have lead to large rounding-off errors. 

Historical Background in Relation to Multiplexed Liquid Crystal Devices... 

THIS article is an overview of time and frequency technology. It introduces basic time and frequency concepts and describes the devices that produce time and frequency signals and information. It explains how these devices work and how they are measured. Section I introduces the basic concepts of time and frequency and provides some historical background. Section II discusses time and frequency measurements and the specifications used to state the measurement results. Section III discusses time and frequency standards. These devices are grouped into two categories quartz and atomic oscillators. Section IV discusses time and frequency transfer, or the process of using a clock or frequency standard to measure or set a device at another location. 

Most scanning electrochemical microscopy (SECM) experiments are conducted in the amperometric mode, yet microelectrodes have for many years been used as potentiometric devices. Not surprisingly, several SECM articles have described how the tip operated in the potentiometric mode. In this chapter we aim to present the background necessary to understand the differences between amperometric and potentiometric SECM applications. Since many aspects of SECM are covered elsewhere in this monograph, we have focused on the progress made in the held of potentiometric microelectrodes and presented it in the context of SECM experiments. Starting with an historical perspective, the key discoveries that facilitated the development and applications of micro potentiometric probes are highlighted. Fabrication techniques and recipes are reviewed. Basic theoretical principles are covered as well as properties and technical operational details. In the second half of the chapter, SECM potentiometric applications are discussed. There the differences between the conventional amperometric mode are developed and emphasized. 

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