摘要:

As a result of the improvements made in the Faraday Effect Apparatus as described, our results indicate an attainable precision of ±0.02 percent for visual measurements. Comparing this value with those reported by other investigators, indicates that a definite increase in precision has been achieved. As soon as our method for making measurements photoelectrically is fully developed, it is expected that the precision will be still higher. This will be especially true in the shorter wave‐lengths where the eye is insensitive, and also where eye fatigue in general would be eliminated.

ISSN:0034-6748    

DOI:10.1063/1.1745507

出版商:AIP    

年代:1950

数据来源: AIP

摘要:

The basic theory of the seismic pick‐up is developed and interpreted to show that it is theoretically possible to make a simple seismic system directly amplitude‐sensitive to velocity as well as acceleration and/or displacement. This is accomplished by appropriate control of the damping.

ISSN:0034-6748    

DOI:10.1063/1.1745508

出版商:AIP    

年代:1950

数据来源: AIP

摘要:

Ilford C‐2 unloaded and C‐2 boron loaded plates, subjected to temperature changes varying from −66°C to +66°C, were bombarded with 10‐Mev neutrons. The recoil protons showed that the temperature change had caused an increase in grain density which varied as much as ⅓ from −66°C to +25°C. Although the C‐2 boron loaded plates showed a greater initial grain density than the unloaded plates, the ⅓ increase was preserved.

ISSN:0034-6748    

DOI:10.1063/1.1745509

出版商:AIP    

年代:1950

数据来源: AIP

摘要:

A detailed description of a Stark‐modulation (see reference 1) microwave spectrograph which has been designed and constructed in this laboratory is given. Circuit diagrams and values of the components are given for all the custom‐built equipment. The frequency range is from 17 to 28 kmc/s.Peak Stark‐modulation voltages up to 1500 volts sine wave and 800 volts square wave are used. The sensitivity is better than 1×10−8cm−1. The absorption lines are about 300 kc wide at half‐power and the practical limit of resolution is between ½ and 1 mc. Frequencies may be measured to better than ±0.08 mc.

ISSN:0034-6748    

DOI:10.1063/1.1745510

出版商:AIP    

年代:1950

数据来源: AIP

摘要:

The aerodynamic heating experienced by thermometers exposed from airplanes can be very nearly eliminated over a wide range of operating conditions by mounting the thermometer in the center of an air vortex created by a simple housing. This method has been found to simplify air temperature measurements over the operating range of a B‐17 airplane. The instrument has promise for measuring temperatures in clouds.True air speeds can be measured by the difference between the temperature of the vortex thermometer and a thermometer exposed in the usual manner. Designs and flight data are presented for several vortex thermometers and a simple true air speed indicator.

ISSN:0034-6748    

DOI:10.1063/1.1745511

出版商:AIP    

年代:1950

数据来源: AIP

摘要:

A time delay circuit is described for timing and sequencing the operations of a cloud chamber. By magnetizing a moving section of recording wire and at a later time using the magnetized section to actuate a sensitive relay, delays from 0.01 to 0.25 second are obtained. The delay can be adjusted visually to an accuracy of 0.001 second.

ISSN:0034-6748    

DOI:10.1063/1.1745512

出版商:AIP    

年代:1950

数据来源: AIP

摘要:

The problem of measuring the phase angle between two sinusoidal voltages is an important one in laboratory procedure. Phasemeters which can make this measurement accurately over a substantial frequency range have heretofore been bulky and relatively stationary. This paper describes a circuit which results in a phasemeter which is accurate to about 30 minutes, has a dial adjustment which is independent of frequency, operates over a range of from 20 c.p.s. to 100 kc and is relatively small and inexpensive. The principle used is to match the phase shift between the unknown voltages with a calibrated phase shift in the meter channel. This phase equalization is observed on a standard oscillograph which is used only as a comparison instrument. The oscillograph amplifier phase shifts are balanced out with an uncalibrated phase shifter cascaded in the meter channel and do not affect the measurement.

ISSN:0034-6748    

DOI:10.1063/1.1745513

出版商:AIP    

年代:1950

数据来源: AIP

摘要:

A positive displacement‐type pump in which there are no metal parts exposed to the fluids has been built and tested. Gases, liquids, or mixtures of both can be pumped without any corrosive effects on the pump.

ISSN:0034-6748    

DOI:10.1063/1.1745514

出版商:AIP    

年代:1950

数据来源: AIP

摘要:

A simple frequency‐modulated pressure gauge employing a variable capacity pick‐up element has been devised to measure the oscillating pressures of burning gases. It has been used to measure pressures in pulse jet engines ranging from −5 to +60 p.s.i. gauge, under conditions where the gas temperatures ranged from approximately 300°K to 2450°K and the gauge mount vibrated with an amplitude of approximately 0.125 inch. The fundamental frequencies of temperature variation, pressure variation and mechanical vibration were 40 cycles and 220 cycles per second. Under these conditions the pressure response is essentially linear from 0 to 5500 cycles per second.

ISSN:0034-6748    

DOI:10.1063/1.1745515

出版商:AIP    

年代:1950

数据来源: AIP

摘要:

The exact equations are derived for operational amplifiers used in analog computers. These exact equations are replaced by simpler equations based upon certain approximations. These approximations are discussed and it is shown, when applied to servo mechanism problems, the operational amplifiers may be designed with greater ease and less complexity than those to be used for more general problems.

ISSN:0034-6748    

DOI:10.1063/1.1745516

出版商:AIP    

年代:1950

数据来源: AIP