Magnetization and magnetoresistance of amorphous FexB1−x in high magnetic fields

The magnetization and magnetoresistance of ferromagnetic melt-quenched amorphous Fe_xB_1?x has been measured. The magnetization indicates no saturation to fields above 30 tesla. The absolute value of the negative magnetoresistivity increases by a factor of five with decreasing B content from x = 0.25 to 0.15. These results are discussed in terms of different models of the resistivity minimum behaviour of amorphous alloys.     

Coherent properties of a macroscopic weakly linked superconductor

A macroscopic weakly linked superconductor has been constructed by compacting aluminum particles which have oxide coatings. The system forms an array of weakly linked junctions and it appears that the whole system behaves in a cooperative fashion when r.f. radiation is incident on the sample.     

On the first factor of the class number of prime cyclotomic fields

Let H(l) be the first factor of the class number of the field $\text{Q}$(exp 2πi/l), l a prime. The best-known upper and lower bounds on H(l) are improved for small l. The methods would also improve the best-known bounds for large l. It is shown that H(l) is the absolute value of the determinant of an easily written down matrix whose only entries are 0 and 1. The upper bounds obtained on H(l) significantly improve the Hadamard bound on the determinant of this matrix. Results of Lehmer on the factors of H(l) are explained via class field theory.     

The interaction of oxygen and nitrogen with the niobium (100) surface: I. Morphology

Low energy electron diffraction has been used to investigate the reactions between nitrogen and oxygen and the (100) face of niobium. Several different oxygen containing surface structures were observed.     

Analysis of uranium-zinc alloys

Zinc can be determined in zinc-uranium alloys by titration with Versene (ethylcnediaminetetra-acetic acid), using Murexide as the indicator. Carbonate is added before the titration to mask the uranium.     

用数学模型计算生长大尺寸光学晶体加热系统结构第2部分-在Ф400mm CaF2晶体生长中计算辐射-传导热交换的方法和结果

大尺寸氟化物晶体的生长是基于对晶体炉热交换的实验研究和计算结果,在晶体生长过程的不同阶段解决了复杂结构生长容器的边界条件和温场的二维计算任务.我们在这里给出了晶体生长过程中温场设置和转变的具体数据.所有的计算都是根据晶体、熔体,容器材料的光学特性与光谱和温度的关系以及它们的热物理值与温度的关系做出的.这些结果包括了迄今有关氟化物晶体生长系统和过程的最精确的数据,可用于生长技术工艺的发展以及晶体生长炉和容器的设计.     

One‐Pot Transformation of Simple Furans into 4‐Hydroxy‐2‐cyclopentenones in Water

A highly efficient one‐pot transformation of readily accessible furans into 4‐hydroxy‐2‐cyclopentenones in H₂O, using singlet oxygen as oxidant, has been developed.