ISSN:0021-8979    

DOI:10.1063/1.1707471

出版商:AIP    

年代:1944

数据来源: AIP

摘要:

The transmission spectrum of natural rubber has been studied in the region between 1&mgr; and 15&mgr; and the effects of linear and radial stretch have been observed. Linear extension greater than 400 percent of the original length produces an increase in the C&sngbnd;C vibrational frequency. Both linear and radial stretch produce an increase in absorption coefficient and a decrease in reflection coefficient. The changes in absorption and reflection coefficients are greatest at short wave‐lengths.

ISSN:0021-8979    

DOI:10.1063/1.1707472

出版商:AIP    

年代:1944

数据来源: AIP

摘要:

A method is presented whereby both the modulus of elasticity in tension and compressionEand the modulus of elasticity in shearGmay be obtained simultaneously from a simple test on a cantilever specimen subjected to combined bending and twist. By means of the relation &ngr; = (E/2G) − 1, values of Poisson's ratio at various temperatures from ambient to 1000°F were obtained for five common steels.

ISSN:0021-8979    

DOI:10.1063/1.1707473

出版商:AIP    

年代:1944

数据来源: AIP

摘要:

In this paper a numerical method is presented for the determination of the characteristic numbers and modes of vibrating (conservative) systems. The method for continuous bodies is based on a finite difference approximation and is a ``relaxation method'' in the same sense as the term is used by R. V. Southwell. No claim is made of theoretical advancement in the subject; the paper purports to present a thoroughly practical method of obtaining numerical answers speedily. Detailed computations are carried out for the transverse vibrations of a quadrangular elastic membrane. The nature of the method is such that it can be easily extended to other vibrating systems of finite or infinite number of degrees of freedom. It is to be emphasized that the quadrangular shape is just a simple example; the real strength of the method lies in the fact that numerical results can be obtained for bodies with more complicated and irregular boundaries.

ISSN:0021-8979    

DOI:10.1063/1.1707474

出版商:AIP    

年代:1944

数据来源: AIP

ISSN:0021-8979    

DOI:10.1063/1.1707475

出版商:AIP    

年代:1944

数据来源: AIP

摘要:

This paper describes a new and simpler method for the determination of orientations of cubic single crystals from back reflection x‐ray photographs by use of vectors in the reciprocal lattice. An example is given to illustrate the usefulness of the method.

ISSN:0021-8979    

DOI:10.1063/1.1707476

出版商:AIP    

年代:1944

数据来源: AIP

摘要:

The group of formulae of Euler and Rodriguez describing the (finite) rotation of a rigid body is written under absolute (coordinate—free) tensor form. Formulae for the products and powers of certain tensors appearing in the transformation formulae are established. By their application, it is shown that the tensor which, operating on a radius vector defining the position of a point of a rigid body with respect to a point0defining the position of the same point after the body has been subjected to a rotation of amplitude &thgr; around an axis containing0, and parallel to the unit vectorh, can be written under the forme&thgr;h×. This representation is compared to the one obtained using quaternions.

ISSN:0021-8979    

DOI:10.1063/1.1707477

出版商:AIP    

年代:1944

数据来源: AIP

摘要:

Single‐ and double‐stub impedance matching on transmission‐line feeders are described. Formulae determining the position and the length of a single matching stub for any load impedance or any observed standing‐wave voltage distribution are derived, neglecting losses in the matching sections. Conditions for minimum length of stub and minimum distance between load and stub are specified. For the double‐stub arrangement, expressions for the lengths of and distance between stubs are derived for any possible combination of load and distance between stubs. A double‐stub tuner with any fixed distance between stubs cannot match all loads to the feeder, and the limits are specified. The optimum location on the feeder of the double‐stub tuner is discussed. A graphical method employing a circle diagram for computing the lengths and position of the stubs is explained. The graphical determination of the stub lengths of the double‐stub tuner is facilitated by auxiliary circular loci which also indicate the range of admittances over which an impedance match may be effected.

ISSN:0021-8979    

DOI:10.1063/1.1707478

出版商:AIP    

年代:1944

数据来源: AIP

ISSN:0021-8979    

DOI:10.1063/1.1707480

出版商:AIP    

年代:1944

数据来源: AIP

ISSN:0021-8979    

DOI:10.1063/1.1707481

出版商:AIP    

年代:1944

数据来源: AIP