ISSN:0034-6748    

DOI:10.1063/1.1751892

出版商:AIP    

年代:1935

数据来源: AIP

ISSN:0034-6748    

DOI:10.1063/1.1751893

出版商:AIP    

年代:1935

数据来源: AIP

ISSN:0034-6748    

DOI:10.1063/1.1751894

出版商:AIP    

年代:1935

数据来源: AIP

ISSN:0034-6748    

DOI:10.1063/1.1751895

出版商:AIP    

年代:1935

数据来源: AIP

摘要:

Straight line, thick film interference fringes are formed between the quartz surface whose normal components of displacement are being measured and an auxiliary optical flat which is supported above this surface by means of a suitable holder. It is advantageous to form these fringes between the auxiliary optical flat and a small optical flat which is attached directly to the quartz surface. With this method one can measure periodic displacements whose amplitudes are even less than a wave‐length of light with an accuracy greater than 99 percent. In measuring the piezoelectric modulusd11, oneYface of a conventional rectangularXcut is rigidly held, an alternating (60 cycles/sec.) electric field applied alongX,and the corresponding displacements of the otherYface measured in the above manner. As required by theory, the normal component of displacement is found to be uniform over theYface. This permitsd11to be measured with an accuracy which is considerably greater than 99 percent. It is necessary to employ electrode arrangements which produce a uniform electric field. The modulusd14is measured from forced extensional vibrations in specially orientedXcuts. Its measurement is found to be more difficult than that ofd11. The final values ofd11andd14are, respectively, −6.22 ±0.03×10−8cm/e.s.u. and +2.24±0.05×10−8cm/e.s.u. These experiments show thatd11andd14are constant in optically and mechanically flawless &agr;‐quartz and that the variations reported by Dawson and by Fox and Fink should be attributed to their experimental error and perhaps to the quality of the quartz employed. A comparison of our values ofd11andd14with those of Pockels shows that the measurements of these moduli by the direct and converse methods agree within the error of experiment. The presence of the strain componentsexyandezxis verified by direct experiment. Their magnitude is of the order predicted by the theory. It is shown that the effect of electrostriction upon the measured values ofd11andd14is negligible. The effect of viscosity is negligible. These measurements can be improved when better means have been devised for generating and measuring high sinusoidal voltages.

ISSN:0034-6748    

DOI:10.1063/1.1751896

出版商:AIP    

年代:1935

数据来源: AIP

摘要:

A two‐crystal x‐ray spectrometer for use in the wave‐length region 0.030<&lgr;<0.215A is described. Transmission and reflection of the x‐rays through the body of the crystal, instead of the usual reflection from the surface, is employed. An ionization chamber containing argon at 80 atmospheres, and an FP‐54 electrometer tube system is used to measure the intensity of the reflected radiation. A source of short wave‐length x‐rays, consisting of two specially designed induction coils and a cascade Coolidge tube, is described. Rocking curves in the (1, −1) position at 50 X.U., theKlimits of lead and of uranium, and theK&agr; andK&bgr;‐lines of tungsten were observed for the purpose of calibrating the spectrometer. The resolving power of the instrument with the present crystals is discussed.

ISSN:0034-6748    

DOI:10.1063/1.1751897

出版商:AIP    

年代:1935

数据来源: AIP

ISSN:0034-6748    

DOI:10.1063/1.1751899

出版商:AIP    

年代:1935

数据来源: AIP

摘要:

The McLeod, Pirani, Knudsen and ionization gauges have been studied as to their suitability in the operation of large metal vacuum systems with organic vapor pumps now coming into extensive use in modern physics. Advantages and disadvantages of each type based on our experience are critically discussed. The superiority of a gauge on the Knudsen principle for this work is stressed and we present a new design and a simpler mode of operation of such a gauge together with a full discussion of its construction, calibration and characteristics.

ISSN:0034-6748    

DOI:10.1063/1.1751900

出版商:AIP    

年代:1935

数据来源: AIP

ISSN:0034-6748    

DOI:10.1063/1.1751902

出版商:AIP    

年代:1935

数据来源: AIP

ISSN:0034-6748    

DOI:10.1063/1.1751903

出版商:AIP    

年代:1935

数据来源: AIP