摘要:

The author describes an apparatus for obtaining clear and informative cinematograph records of the movements of parts of the human body as revealed by X-rays. He also outlines his experimental work on incorporating in the cinematographic record of the heart beat a synchronous tracing of the electrical output of the heart as recorded by the Cossor-Robertson and Cambridge electrocardiographs. He suggests future development of indirect X-ray cinematography, especially in the use of the sound track for the study of the heart, respiration, and speech.

DOI:10.1049/jiee-1.1936.0165

出版商:IEE    

年代:1936

数据来源: IET

摘要:

The insulation of high-tension lines in industrial areas is one of the major problems in the operation of high-tension systems. This paper gives the results of an investigation into the electrical characteristics of 132-kV insulators under various weather conditions in a district subject to atmospheric pollution. It was found that the steady value of the leakage current of an insulator chain varies between 0.2 and 1.0 mA, depending on the weather conditions. In fog or with dirty insulators under humid conditions the leakage current is very unsteady and continuous surging usually takes place, the magnitude of the current-surges often reaching 100 mA. These current-surges are due to surface discharges on the insulators and are usually self-extinguishing owing to the resistance of their path being increased by the heating effect of the current, but a severe surge may develop into a complete flashover. The frequency and magnitude of these current-surges provide a criterion by which to judge the performance of insulators. Information is also given on the surface resistivity of porcelain, the characteristics of some special types of insulators, and the cleaning of insulators.

DOI:10.1049/jiee-1.1936.0168

出版商:IEE    

年代:1936

数据来源: IET

摘要:

This paper gives a description of the methods developed at the National Physical Laboratory for the manufacture of selenium rectifier photocells, followed by results showing the characteristics of these and a number of other cells of this class which are available commercially. The characteristics of the cells are discussed in the light of the requirements essential for accurate photometry.The paper is intended as a general survey of the present state of the subject.

DOI:10.1049/jiee-1.1936.0170

出版商:IEE    

年代:1936

数据来源: IET

摘要:

This paper is devoted to a detailed study of the selenium rectifier type of photo-electric cell, only brief reference being made to the development of the dry rectifier cell from the original “Lange” cell. It is mainly an investigation into the difficulties met with and the precautions necessary when employing this type of photo-electric cell for photometric measurements. Hence experiments were carried out to show:—(1) The effect of illumination and current generated on the internal resistance.(2) The effect of the external resistance on the linearity of the current response.(3) The effect of temperature on the current generated, internal resistance, and voltage developed, for a given illumination.(4) The effect of intermittent illumination on the cell sensitivity, etc.In an endeavour to overcome the effect of the external resistance and temperature the possibilities of the Campbell- Freeth compensation circuit were investigated. The results obtained indicate that the generated current is strictly proportional to the illumination and that it is unaffected by temperature.Further, the effect of applying an external voltage was investigated for different values of the illumination. The advantages of the slightly increased sensitivity gained are greatly outweighed by the disadvantages of having auxiliary apparatus.It should be noted that only a limited number of cells were available for test, and as cells vary considerably between one another the numerical results must only be taken as a guide to the values to be expected.

DOI:10.1049/jiee-1.1936.0171

出版商:IEE    

年代:1936

数据来源: IET

摘要:

The first section deals briefly with the experimental confirmation of the theory of the axial focusing coil.It is shown in the second section that the supposed difference between the actual and the calculated electrostatic sensitivities in the gas-focused oscillograph is non-existent when the necessary allowance is made for the fringing field a t the edge of the deflecting plates. The agreement between the magnetic sensitivities is also confirmed.The investigations described in the third section show that the screen materials are insulators and that the potential of the fluorescent spot is about 60 volts below that of the anode and independent of the beam current or energy over a wide range. The influence of this potential on the sensitivity of the beam is almost negligible.

DOI:10.1049/jiee-1.1936.0174

出版商:IEE    

年代:1936

数据来源: IET

摘要:

With the advance in the technique of producing plastic mixtures which are suitable for the manufacture of moulded articles, an acute desire has arisen amongst engineers for some ge'neral guidance in the selection of materials which will be found suitable for definite purposes.This contribution contains an account of the various materials available and the characteristics associated with them; and finally a descriptive classification is suggested where recommended types of materials with typical examples are given, which will be found suitable for nearly every purpose required in both electrical and mechanical engineering.The descriptive classification should prove of special value, owing to the absence of a comprehensive British Standard Specification covering the whole range of uses dealt with.

DOI:10.1049/jiee-1.1936.0175

出版商:IEE    

年代:1936

数据来源: IET

摘要:

The instruments described were developed in the course of a research in which steady measurements of high peak voltages were necessary. For this purpose the ionic wind voltmeter was found to be most suitable and has been used in works practice to provide a means of observing test voltages without the surge set up by the passage of a spark across a measuring gap. Wimshurst voltages were used on an X-ray research and were readily measured by the same instrument. The ballistic ellipsoid instruments were designed to deal with transient X-ray voltages and currents.

DOI:10.1049/jiee-1.1936.0176

出版商:IEE    

年代:1936

数据来源: IET