ISSN:0021-8979    

DOI:10.1063/1.1712762

出版商:AIP    

年代:1940

数据来源: AIP

ISSN:0021-8979    

DOI:10.1063/1.1712763

出版商:AIP    

年代:1940

数据来源: AIP

ISSN:0021-8979    

DOI:10.1063/1.1712766

出版商:AIP    

年代:1940

数据来源: AIP

ISSN:0021-8979    

DOI:10.1063/1.1712767

出版商:AIP    

年代:1940

数据来源: AIP

摘要:

The inter‐relation between the chemical constitution and structure of plasticizers and plastics is discussed. The results obtained with sulfonamide, phthalate and phosphate plasticizers in cellulose acetate compositions are used as examples and the author speculates on the possibility of formulating general rules from such data.

ISSN:0021-8979    

DOI:10.1063/1.1712768

出版商:AIP    

年代:1940

数据来源: AIP

摘要:

Using a metal radio tube having a steel shell as an ionization gage, the diffusion of hydrogen through the steel into the interior was measured. This results from the fundamental corrosion reaction on the exterior, when it is dipped into water:Fe+H2O=FeO+H2.The protective paint on the tube prevents this, but a bare sandblasted iron surface admits hydrogen at 0.13 micron per hour with the shell in water at 25°C. Hydrogen does not diffuse into the tube when water vapor alone surrounds it. Rates of diffusion were measured through plain and composite metal shells, varying surface treatment and temperature.

ISSN:0021-8979    

DOI:10.1063/1.1712769

出版商:AIP    

年代:1940

数据来源: AIP

摘要:

In an attempt to determine the fraction of ions lost by recombination in an x‐ray ionization chamber, a theory has been developed for the processes involved in preferential and initial ionic and electronic recombination. The theory considers the change of the energy distribution of the electrons as they diffuse away from the parent atom. From this, together with a knowledge of the electron capture process, the space distribution of negative ions formed may be obtained. The probability of the initial electron recombining preferentially with the parent positive ion is considered as well as the preferential process for the negative ion. Knowing the initial spacing of the ions, it is possible to calculate the recombination occurring during the diffusion process until random distribution is reached. The final volume recombination may then be calculated in the usual manner. The theory may be employed in both electronegative and free electron gases and to ions formed in the presence or absence of an electric field.

ISSN:0021-8979    

DOI:10.1063/1.1712770

出版商:AIP    

年代:1940

数据来源: AIP

摘要:

This paper describes experiments on the birefringence of a strip of plastic material, first when the stretched strip is maintained at constant length and second when it carries a constant load. The results indicate that in neither case is the birefringence proportional to the tension. The data are further examined, and the argument is presented to show that in the constant length experiment the ratio of tensionTat any time after the initial tension,T1, is established should be the same function of the time as is the expression[1−2&mgr;logeLL1]for the constant load experiment. Finally it is shown that the tension ratio data can be represented by a curve of the type,T′T1=Ae−at+Be−bt+Ce−ct.

ISSN:0021-8979    

DOI:10.1063/1.1712771

出版商:AIP    

年代:1940

数据来源: AIP

摘要:

The Lagrangian equations of motion of a general mechanical system ofndegrees of freedom that is executing small motions about a position of equilibrium are subjected to a Laplacian transformation. The transformed equations are then subjected to a similarity transformation. By means of this transformation, a separation of the transformed equations is effected provided the system has the special type of symmetry under consideration. The solution of the usual determinantal equation is avoided. The methods of the Laplacian transformation and matrix algebra as presented in (1) and (2) are assumed in the discussion.

ISSN:0021-8979    

DOI:10.1063/1.1712772

出版商:AIP    

年代:1940

数据来源: AIP

摘要:

This paper considers numerical methods for the solution of Poisson's equation in an arbitrary two‐dimensional region with given boundary values. The methods are similar to those discussed by Shortley and Weller for Laplace's equation. It is shown that the entire theory of networks may be applied to Poisson's equation without change. Formulas for the treatment of irregular points and for blocks of points are developed. In addition to the mathematical considerations, the application of the methods to the case of torsion in shafts of any cross section is described. Additional formulas are derived for the determination of the maximum shear at any point in a shaft as well as the torsional stiffness of such a shaft.

ISSN:0021-8979    

DOI:10.1063/1.1712773

出版商:AIP    

年代:1940

数据来源: AIP