二氯喹啉酸氧化工艺探讨

本文提出了二氯喹啉酸氧化工艺的最佳条件。结果表明该法具有反应条件温和，反应时间短，操作成本低，废不减少和收率高等优点。     

The influence of scattering on magnetic breakdown

A study of magnetic breakdown between the third zone needles and second zone monster surfaces in the three zinc alloy systemsZnMn,ZnCr, andZnFe shows that the tunneling probability is strongly reduced by electron scattering and that the breakdown fieldH ₀ increases linearly with the Dingle temperatureX with a scaling factor of 0.36 kG/K for all alloys. This phenomenon may be understood if we allow the electrons to be scattered during their tunneling through the forbidden region ofk space. A simple semiclassical calculation of this effect yields an expression for the breakdown probability corrected from the conventional expression toP=exp[–(1/H)(H₀+X)], where is a constant dependent only on the band structure of the solvent.     

Precise lattice parameter determination of dislocation-free gallium arsenide—II: Chemical and electrical measurements

Precise lattice parameter measurements on dislocation-free gallium arsenide were described in Part I (preceding paper).² Detailed chemical and electrical analyses of the same samples are described here. The predictions of simple chemical models are developed in the light of the analytical results. The significant observed increase in lattice parameter due to silicon doping, in contrast to the predicted decrease, is discussed.     

Practice of computer use in radiotherapy planning

The main problems of radiotherapy planning are discussed with respect to use of computers now being available for a greater number of centers. One of the most essential premises is apart from clear ideas on a modern target volume concept - a sufficiently high speed in producing realistic summarized isodose contours for any radiation therapy arrangement in any individual patient's cross section outline. This problem being solved, those individual summarized isodose figures have to be critically evaluated and therefore the importance of applicable meaningful optimization criteria come into account. The properties of such criteria, which must be quantifiable, generally applicable and really relevant for judgement on quality of a plan, had to be accepted, before automatic optimization procedures could be developed; principles involved are presented. By means of a short series of examples, namely 60Co fixed field combinations with and without use of wedges, combinations of arc therapy for a number of clinical tasks. It has been pointed out, that most experienced estimate by the eye would have been by far insufficient when compared to the automized computer optimization when using such simple criteria as 1. homogeneity of absorbed dose within target volume, 2. numerically limited absorbed dose within areas of risk, 3. as low as possible radiation effects to all "outside areas". It seems to be a real danger, that so called isodose libraries, how high their merits might be estimated, may change into an "isodose bcemetery", unless we'll be successful for each individual clinical case by use of computers, which are now prepared to supply the best possible variant of the standard plan or the primary radiotherapy idea. Regular use of computers in such a way will furthermore give an incomparable documentation material.