摘要:

Although crystallization is a very familiar phenomenon the mechanisms whereby it occurs have proved to be subtle and difficult to establish. For this reason the subject has held great interest, both scientifically and technologically, for a long time.

ISSN:0031-9228    

DOI:10.1063/1.3060635

出版商:AIP    

年代:1959

数据来源: AIP

摘要:

A meeting of the Radiofrequency Spectroscopy Group was held in Newcastle on September 22nd and 23rd to discuss recent work on “Magnetic Resonance of the Solid State”. The number attending this meeting and the keen interest in the work reported were striking evidence of the increasing power of these new techniques as a probe into the details of solid‐state structure and interactions. The general theme of the discussion was the study of impurities and defects in ionic crystals, which appropriately linked with the research being carried out by Dr. Schneider's group at Newcastle itself. The study of impurity and defect centers is a subject in which magnetic resonance is making very considerable contributions at the moment, in a somewhat similar way to its applications in detailed organic analysis and the investigation of free‐radical systems on the more chemical side.

ISSN:0031-9228    

DOI:10.1063/1.3060636

出版商:AIP    

年代:1959

数据来源: AIP

摘要:

The first Symposium on Nonhomogeneity in Elasticity and Plasticity was held in Warsaw, Poland, from the 2nd to the 8th of September. It was the first meeting in Poland sponsored by IUTAM (the International Union of Theoretical and Applied Mechanics) and our hosts, led by W. Olszak, spared no effort to make the occasion both memorable and pleasant. Social events and sightseeing trips interlaced and surrounded the very full technical program. From the time of personal greeting upon our arrival at the airport to the time of waved goodbyes, help and advice were available instantly if needed. On the other hand, we were completely free to look around on our own and to visit any place we pleased by foot or by taxi.

ISSN:0031-9228    

DOI:10.1063/1.3060637

出版商:AIP    

年代:1959

数据来源: AIP

摘要:

The current discussion about a unified scale of nuclidic masses and atomic weights * grew out of a desire to correct the indefiniteness of the chemical scale of atomic weights which results from variations in the isotopic composition of natural oxygen. Oxygen, with a defined atomic weight of 16, has been the universally accepted reference element for atomic weights since early in the present century. Earlier many chemists favored a scale based on hydrogen, with a definite atomic weight of unity. The hydrogen scale originated with Dalton and doubtless enjoyed support on the basis of Prout's hypothesis that the hydrogen atom is the structural unit in the atoms of all other elements. However, the operational advantages of oxygen in stoichiometric determinations of atomic weights offset the logical arguments for hydrogen and in time brought about the general acceptance of the oxygen scale. It was natural to assign a whole number, sixteen, to oxygen, rather than the nonintegral number representing its atomic weight on the hydrogen scale. Thus the unit of atomic weight became one‐sixteenth the weight of an atom of oxygen.

ISSN:0031-9228    

DOI:10.1063/1.3060638

出版商:AIP    

年代:1959

数据来源: AIP

摘要:

There exist at present three scales of atomic masses or weights: (1) the absolute scale based on the gram, (2) that defined by taking the mass of one atom of the nuclideO16equal to 16 units (the “physical scale” of “atomic masses” or “nuclidic masses”), and (3) that taking the average atomic mass of the isotope mixture of “natural” oxygen as 16 units (the “chemical scale” of “atomic weights”). Of these, only the last two are in common and extensive use. The chemical scale is indefinite to the extent of the variation in the average atomic mass of oxygen from various natural sources (some IS parts per million) resulting from variations in the relative proportions ofO16,O17,andO18.

ISSN:0031-9228    

DOI:10.1063/1.3060639

出版商:AIP    

年代:1959

数据来源: AIP

摘要:

New physics buildings or renovated quarters for physics departments are now being planned by nearly half of the colleges and universities in the United States that offer a major in physics. In recognition of the importance to physicists of this anticipated construction activity, a systematic study of factors to be considered in designing physics buildings will be carried out during the next eighteen months under the joint auspices of the American Association of Physics Teachers and the American Institute of Physics. Made possible by a grant of $75 850 from the Educational Facilities Laboratories, Inc., the study will be directed by R. Ronald Palmer of Beloit College, a former president of the AAPT who is currently a member of the Institute's Governing Board.

ISSN:0031-9228    

DOI:10.1063/1.3060640

出版商:AIP    

年代:1959

数据来源: AIP

ISSN:0031-9228    

DOI:10.1063/1.3060643

出版商:AIP    

年代:1959

数据来源: AIP

ISSN:0031-9228    

DOI:10.1063/1.3060646

出版商:AIP    

年代:1959

数据来源: AIP

ISSN:0031-9228    

DOI:10.1063/1.3060647

出版商:AIP    

年代:1959

数据来源: AIP

ISSN:0031-9228    

DOI:10.1063/1.3060648

出版商:AIP    

年代:1959

数据来源: AIP