摘要:

The principles involved in the transfer of low boiling liquids under their own vapor pressures are indicated and calculations are presented for the specific case of the transfer of liquid nitrogen. A convenient device for transferring liquid nitrogen by this procedure is described and its operating characteristics are compared with the calculations.

ISSN:0034-6748    

DOI:10.1063/1.1745660

出版商:AIP    

年代:1950

数据来源: AIP

摘要:

An analysis is made of the focusing characteristics of a magnetic spectrometer having an annular magnetic field which varies approximately with 1/r½, thus permitting axial as well as radial focusing of particles of a given energy. By considering the field angle and source location as independently variable, the analysis provides for an instrument more flexible in use than similar existing types.An optical analogy is developed from which a first approximation to the field shape is made, and from which the source and image location, magnification, dispersion and resolution can be readily obtained. Information thus obtained, combined with the results of an investigation into the image shape based on a series expansion, through second order, of expressions for the field strength and particle coordinates, yields more detailed information on the field shape which gives optimum focusing conditions and resolution for any chosen set of initial conditions.Comparisons are made with the homogeneous field spectrometer and with the spectrometer of Svartholm and Siegbahn.

ISSN:0034-6748    

DOI:10.1063/1.1745661

出版商:AIP    

年代:1950

数据来源: AIP

摘要:

A circuit for driving a long coaxial cable is described. Its response characteristics permit impedance matching of the coaxial line without sacrificing linearity of response, and make possible a relatively long line between the particle detector and the recording apparatus. The circuit was found to be reasonably stable for long periods of time, even under severe outdoor operating conditions.

ISSN:0034-6748    

DOI:10.1063/1.1745662

出版商:AIP    

年代:1950

数据来源: AIP

摘要:

A new vacuum gauge has been developed that is capable of measuring pressures from one atmosphere down to less than 10−5mm Hg. The principle and construction of the gauge and experimental results are given.

ISSN:0034-6748    

DOI:10.1063/1.1745663

出版商:AIP    

年代:1950

数据来源: AIP

摘要:

Total radiated heat loss and average surface temperature of living bodies have heretofore required laborious computation from numerous local measurements. The present study introduces the blackbody principle for this objective. Shieldless surface receivers have been designed, and built from identical and symmetrical sets of thermoelectric foil junctions, which were then made different only in their power to absorb or reflect radiation. By means of thermal shunting, they have been rendered stable against air motion up to 8 m/sec. A cavity, when uniformly lined with such receivers, will integrate the measurements of radiated output into every direction of space, permitting a direct recording of the total. The receivers have been developed specifically for application to the human gradient calorimeter now under construction. However, since the laws of radiation apply to cavities of any size or shape, the proper function of blackbody radiometry could be experimentally verified with a smaller number of receivers in a body of 8×8×16 cu. in. The 4&pgr;‐measurement is practically independent of location, size, or shape of the emittent source. The sensitivity is 76 &mgr;v/cal./sec. Full response is attained within 2.4 sec.

ISSN:0034-6748    

DOI:10.1063/1.1745664

出版商:AIP    

年代:1950

数据来源: AIP

摘要:

This instrument produces, automatically, a curve of torqueversusangle of orientation for a thin iron or steel disk in a strong magnetic field. A resistance strain gauge converts the torque acting on the disk specimen to a small d.c. voltage, which is recorded on a ``strip‐chart'' recording potentiometer. The specimen is rotated in synchronism with the translation of the chart paper, both being driven by synchronous motors. A torque curve is completed in six minutes.

ISSN:0034-6748    

DOI:10.1063/1.1745665

出版商:AIP    

年代:1950

数据来源: AIP

摘要:

A new device for the distribution of vapors across an electron beam for molecular diffraction studies is described. The efficiency of the new method has made it possible to obtain molecular diffraction patterns with an electron microscope without need of alterations.The vapors are ejected from a circular crest of a diffusion box immediately surrounding the beam to give a heavy concentration of vapors in contact with the beam while releasing a small amount of vapor. The method has been standardized with well known patterns of CCl4and CBr4.

ISSN:0034-6748    

DOI:10.1063/1.1745666

出版商:AIP    

年代:1950

数据来源: AIP

摘要:

This paper describes apparatus for measuring internal friction which satisfies the conditions (a) low induced stress amplitude to preclude any plastic flow of the specimen, (b) ability to install specimen within a few minutes after treatment, (c) rapidity of measurement, at a rate of ten to twenty per minute, (d) accuracy of at least one percent.Longitudinal vibrations are induced by an eddy‐current drive, similar to one previously described in the literature, satisfying (a) and (b). Conditions (c) and (d) are obtained by measuring the decay time of free vibrations using vacuum tube trigger circuits and a counter chronograph. Satisfactory measurements can be made with push‐button rapidity and simplicity.

ISSN:0034-6748    

DOI:10.1063/1.1745667

出版商:AIP    

年代:1950

数据来源: AIP

摘要:

A series of experiments designed to yield information on the mechanisms of ultra‐high frequency discharges which influence the operation of ion sources employing such discharges is described. The main conclusions are that such discharges exhibit a high negative space charge due principally to secondary emission from the walls of the discharge chamber and that ion production is inhibited by the space‐charge trap so formed, that under certain conditions extremely intense electron beams may be obtained from a resonant cavity containing a gas discharge, and that fairly large ion currents may be obtained by the interaction of the emergent gas and the emergent electron beam in the exit orifice of the cavity.

ISSN:0034-6748    

DOI:10.1063/1.1745668

出版商:AIP    

年代:1950

数据来源: AIP

摘要:

An apparatus for the power stabilization of medium‐level microwave power sources, intended for laboratory use, by means of a degenerative feed‐back network connected in tandem with the power source is described. An analysis of the operation of the network is presented, based on obtaining optimum stabilizing action and optimum transmission efficiency for the network. Design of an electrically‐operated attenuator (which is a servo device), and its effect on the stabilization characteristics of the network are discussed. A transmission efficiency of 70 percent and a stabilization factor of 21 were obtained in an experimental model.

ISSN:0034-6748    

DOI:10.1063/1.1745669

出版商:AIP    

年代:1950

数据来源: AIP