Levelcrossing Experimente im Tm I-Spektrum

A semi phenomenological dynamical theory for the rotations of the BO₆ octahedra in ABO₃ perovskites is proposed, which accounts for the soft mode and the central peak forT≧T _c observed by neutron scattering in SrTiO₃. The neutron scattering cross section is discussed. The EPR line width is predicted to diverge as ?^?ν(1–2η) and as ?^?ν(2–2η) for three- and two dimensional correlations with ?=(T-T _c )/T _c . The theory is generalized to other structural transitions.     

Experimente und Modellrechnungen zur Emission im UV-Stickstofflaser

Experiments and Model Calculations on the Emission in the UV-nitrogen Laser Experiments are described which deal with emission in nitrogen lasers. The experimental results have been discussed with known models of emission. The influence of plasma on the radiation has been considered. With the model of amplified spontaneous emission the measured starting point of the beam, and the divergence of the stimulated radiation field could be described. The discrepancy between measured laser pulse energy as a function of laser length and calculation has been interpreted as the influence of decreased group velocity of laser pulse in the non-saturated laser medium. Radiation with small divergence and relatively high power has been generated with a telescope between laser tube and mirror.     

爱因斯坦:机遇与眼光

各位同学，大家好。今天我们很高兴能请杨振宁先生来给我们作报告。大家都知道，今年是世界物理年，1905年爱因斯坦发表了5篇划时代的重要论文，为相对论的建立和发展奠定了基础，为量子理论的发展做出了重要贡献，从根本上改变了物理学的面貌。今年恰好就是这几篇重要论文发表100周年，所以联合国教科文组织把今年定为世界物理年。     

Experimente und Berechnungen zur Hyperfeinstruktur der 3d 9 5g-Konfiguration im Kupfer II-Spektrum

The 3d ⁹ 5g-configuration in the Cu II-spectrum is an example for extreme(j _d l _g )K-coupling. It is shown how under these circumstances experimental hyperfinestructure separations can be explained and calculated by means of the concept of intermediate coupling between two basic coupling schemes. The basic schemes used are built on the vectorK coupled either to the spins of the outer 5g-electron or to the nuclear spinI. The value of the experimental magnetic separation factorya _j (3d) can be understood as the consequence of the core polarization of the inners-electrons by the spin of the unfilled 3d-shell. — The measured effective spin-orbit-constantζ _5g is three times larger than the theoretical result. Reasons for this discrepancy will be discussed.     

Experimente an einem Plasmabetatron

Recently reported measurements on a plasma betatronM II were continued and under certain conditions bremsstrahlung produced by relativistic electrons was observed associated with conduction currents of some 100 A. But also early beam disruption occured. The time τ_gg of disruption of the stream has been measured as a function of gas pressure and acceleration field strength. Most of the electrons were lost during an early stage of the acceleration process but also beam loss was observed over a long period of the acceleration time. The expected increase of the circulating runaway current due to improved parameters was not found.     

Experimente zur Elektronenoptik elektrostatischer Beschleuniger

RecentlySonoda and coworkers found discrepancies betweenTimm's theory of electrostatic lenses and experiments. Very few experimental data having been available, measurements were made of the cardinal elements of electron lenses, using the method described byKlemperer. This method is based on the exact measurement of the small cross section of an electron beam. The beam was scanned by means of an electronic equipment and was made visible on a television screen. The results proved to be approximated byTimm's theory only roughly. Consequences for the calculation of accelerating tubes are discussed.