A physical model for the stress-induced electromagnetic effect in metals

Observations of the fracture-induced electromagnetic effect in metals have recently been reported by the author. This paper presents a physical model for explaining this new effect. The reasoning attributes the observed electromagnetic effect to dislocationelectron interactions in a metal. The frequency of the emitted radiation has been calculated from Bohr's correspondence principle and potential on the basis of Hertzian dipole radiation. The proposed physical model predicts emission of electromagnetic waves at distinct transition stages of elastic-plastic deformations. The paper also presents some of the experimental results, being obtained by the author, which confirm the practicability of this approach.     

Furfuroxides of lanthanum,praseodymium, neodymium,and samarium

Ln(R)₃, Ln(R)₂(OPrⁱ), and Ln(R)(OPrⁱ)₂ (where Ln = La, Pr, Nd, and Sm; R = deprotonated furfuryl alcohol, RH) were prepared from lanthanide isopropoxide and furfuryl alcohol in 1:3, 1:2 and 1:1 stoichiometric ratios respectively in anhydrous benzene under reflux. Ln(R)₂-(OPrⁱ) and Ln(R)(OPrⁱ)₂ were also obtained at room temperature. The isopropoxy group(s) of these derivatives were replaced by tertiary butoxy group(s) during the alcohol exchange reactions with tertiary butanol. All these derivatives are soluble in benzene except the tertiary butoxy derivatives which are only sparingly soluble. However, they become insoluble on standing. These furfuroxides did not distil at ～300°C/10² torr but decomposed. Isopropoxy/butoxy furfuroxides were characterized by the elemental analysis and also by estimating the liberated isopropanol. The i.r. spectra of Ln(R)₃ clearly supports the presence of furfuroxide groups in these derivatives.     

Evidence of incipient bond-stretching isomerism in Sr2.04(1)Ca0.96(1)Sn5 from variable-temperature structural studies

The title compound was found to crystallize in the Pu3Pd5 structure type (SG Cmcm) with cell dimensions of a = 10.5179(9) A, b = 8.4789(8) A, and c = 10.7623(10) A. The structure consists of isolated Sn5(6-) square-pyramidal units surrounded by cations that seem to play a crucial role in stabilizing the Zintl polyanions. The square pyramids contract at low temperatures (100 K) leading to the shortening of the basal intracluster Sn-Sn bond (2.74 A), while the intercluster bonds become very large, indicating features of bond stretching isomerism as is known for Ba3Ge4. A study of different crystals shows a slight variation in the lattice parameters, suggesting the presence of a definite phase width which was substantiated by the successful synthesis of monophasic samples of Sr(3-x)CaxSn5 (0.5 相似文献   

A novel rearrangement from eudesmanolide to adamantanone

A novel cyclization-skeletal rearrangement from a eudesmanolide, 3-desoxy-4β, 5αH-hexahydro-?-α-santonin(1) to an adamantanone, 2, 5, 9-trimethyltetracyclo [6. 3. 1. 0^1,6. 0^5,10]dodecan-11-one(2) was found to occur as the result of a most unusual reaction. The structure of 2 was elucidated by the X-ray diffraction method.     

Purification of orthodiphenol oxidoreductase from potatoes by affinity chromatography on coir pith lignin

Orthodiphenol oxidoreductase, ODOR (E.C.I.10.3.1) from potato tubers (Solanurn tuberosum) has been purified on coir pith lignin by affinity chromatography. All isozymes get adsorbed and can be eluted with 70% recovery. The enzyme shows high purity, as judged by specific activity and polyacrylamide gel electrophoresis.     

Plasmon excitation in the x ray absorption process

A simple approach is developed to study the excitation of a plasmon due to valence electronic correlations in the x ray absorption process. Assuming a complete separation between the core and the valence electrons, we introduce the plasmons in the system Hamiltonian externally according to the Bohm-Pines collective formalism and carry out the corresponding canonical transformations to separate the x ray photonplasmon-electron term. According to our calculations, the relative intensity of the plasmon process with respect to the main absorption, which represents single particle excitations is 0·12 times the interelectronic separation measured in Bohr radii. The theoretical estimates of the plasmon intensity agree satisfactorily with the experimental values for the Mn K and the Re L_III absorption discontinuities. The shape of the plasmon absorption band resembles the main absorption edge, if the wave vector dependence of the plasmon frequency is neglected. The intensity of the second plasmon harmonic is about 3 per cent of the first plasmon satellite spectrum. The electron plasmon interaction modifies the shape of the plasmon spectrum.