摘要:

A thermal conductivity apparatus based upon the increase of temperature of a receiver by heat transferred through the sample is described, and its modification to samples inclined to the horizontal. The temperature changes of the receiver are measured with thermocouples, the reference junction of which is at room temperature.

ISSN:0034-6748    

DOI:10.1063/1.1740853

出版商:AIP    

年代:1947

数据来源: AIP

摘要:

A system for analyzing the ion beam of an electrostatic generator is described. A weak magnetic field separates protons from heavier components and a 90° electrostatic deflection gives the required energy resolution. With the analyzer controlling the generator voltage, a proton beam of one microampere with an energy spread of the order of 300 volts in one million is obtained.

ISSN:0034-6748    

DOI:10.1063/1.1740854

出版商:AIP    

年代:1947

数据来源: AIP

摘要:

The laboratory oscilloscope is designed primarily for use in the nuclear physics laboratory but is a versatile instrument well suited to general circuit research. It contains a sweep generator with writing speeds ranging from 8 inches per microsecond to 1 inch per millisecond. The sweep is initiated by a voltage amplitude discriminator which may be triggered by: (a) an internal trigger generator operating at variable repetition rates, (b) a jitter‐free delayable trigger which may be generated at any time from minus 2 to plus 400 microseconds with respect to a fixed trigger from the master generator, (c) from any arbitrary signal greater than 5 volts, and (d), any input to the signal amplifier larger than 0.2 volt. A high fidelity delay line is incorporated in the amplifier circuit so that the sweep may be initiated by the input signal to the amplifier before the signal appears at the scope plates. A 1‐volt input to the amplifier will give a 1½‐inch screen deflection with a minimum rise time of 0.15 microsecond. The trigger generator, which starts the delay circuits, may be triggered externally by pulses of 15‐volts amplitude or more. Sufficient voltage is applied to the type‐5CP11 scope tube to permit photography of transients with writing speeds of 3 inches per microsecond using a camera with anf:2 lens opening and Ansco Fluorapid film or Eastman 103–0 plates.

ISSN:0034-6748    

DOI:10.1063/1.1740855

出版商:AIP    

年代:1947

数据来源: AIP

摘要:

An electrical network for determining the eigenvalues and eigenvectors of a real symmetric matrix of ordernis described. It consists ofn LC‐circuits, each one coupled to each of the others by two condensers. The values of the condensers are adjusted according to the elements of the matrix. Both positive and negative values of the elements can be dealt with by changing the connections of the coupling condensers. The network is excited by a variable frequency source, the resonance frequencies being observed on an oscillograph. The eigenvalues are given by these resonance frequencies and the components of the eigenvectors by the voltages across the coils. The construction of the network and the operating procedure are described. The theory of the network when losses in the coils are taken into account is also given, and the case of multiple roots is discussed. The accuracy of the eigenvalues obtained is better than 0.1 percent of the greatest eigenvalue, while the accuracy of each eigenvector is about one percent of its greatest component.

ISSN:0034-6748    

DOI:10.1063/1.1740856

出版商:AIP    

年代:1947

数据来源: AIP

摘要:

A method is described whereby a wide range recording system having good accuracy may be obtained with a 10‐inch chart. The peaks to be recorded are first obtained on a highly compressed scale which is approximately logarithmic. Immediately after reaching the peak top on the non‐linear scale, a system of relays selects a linear scale of the appropriate sensitivity, and the peak top is re‐recorded on the linear scale. With this system all peaks between 4″ and 500″ (i.e., between 24 mv and 3000 mv) are recorded between 4″ and 10″. As a result, measurement of peak heights becomes a simple process, and wide range is obtained without loss of accuracy. Complete details are given for construction of this system.

ISSN:0034-6748    

DOI:10.1063/1.1740857

出版商:AIP    

年代:1947

数据来源: AIP

摘要:

In a mercury‐vapor trap of appropriate design an alloy of sodium with 5 to 10 percent potassium is more satisfactory than either of the metals used alone. The trap does not need reactivation at intervals and, therefore, during its life affords continuous protection from mercury vapor. Over a period of twenty‐two days a vacuum system protected by this type of trap was pumped repeatedly from atmospheric pressure to 5×10−7mm of Hg; during this time the trap required no attention.

ISSN:0034-6748    

DOI:10.1063/1.1740858

出版商:AIP    

年代:1947

数据来源: AIP

摘要:

Nuclear radiofrequency absorption can be observed by means of a super‐regenerative detector. The sample is placed in the coil of the resonant circuit, and reacts to produce an observable signal by nuclear absorption when the external magnetic field is such as to produce a Larmor precession at the same frequency as that of the super‐regenerative detector. An autodyne detector, oscillating weakly, can also be used to observe nuclear resonance absorption.

ISSN:0034-6748    

DOI:10.1063/1.1740859

出版商:AIP    

年代:1947

数据来源: AIP

摘要:

The addition of a high resistance shield to the guard ring of a parallel‐plate condenser reduces the fringe effect to a negligible value so that the precise computation of capacitance is simplified.

ISSN:0034-6748    

DOI:10.1063/1.1740860

出版商:AIP    

年代:1947

数据来源: AIP

ISSN:0034-6748    

DOI:10.1063/1.1740861

出版商:AIP    

年代:1947

数据来源: AIP

ISSN:0034-6748    

DOI:10.1063/1.1740862

出版商:AIP    

年代:1947

数据来源: AIP