The electrical breakdown and electrical conduction of ethylene copolymers have been studied. The electric strength of ethylene copolymers containing an optimum content of halogen moieties such as bromophenyl and fluoroethylene groups was found to be higher than that of LDPE over the wide temperature range from ?196°C to 90°C. Also, conduction currents in the copolymers were suppressed at high electric fields. X-ray-induced thermally stimulated currents (TSC) revealed that halogen comonomers act as carrier traps with a depth of about 0.4 eV. Consequently, the introduction of comonomer-containing halogen groups into polyethylene suppresses electron acceleration as a result of an increase in trapping and scattering of conduction electrons. This leads to an increase in electric strength which is determined by the electron avalanche breakdown. 相似文献
Two-dimensional statistical functions such as spectral density function, coherence function and phase angle are used to evaluate the single and joint segregation characteristics of alloying elements. Employing the latter two functions, the joint segregation index, defined elsewhere for a one-dimensional case, is redefined for a two-dimensional one. The effects of calcium treatment on center segregation (macrosegregation) and intergranular segregation (semi-macrosegregation) of MnS in three commercial calcium treated steel slabs, continuously cast under different operating conditions, are quantified by using the joint segregation index. The results are compared with those of a slab without calcium treatment. It is shown that both center segregation and intergranular segregation of MnS in all three calcium treated slabs are suppressed as compared with the slab without calcium treatment, and that the extent of the effect depends on the casting conditions. By reasoning on the basis of two-dimensional power spectra, it is shown that in a calcium treated slab sulfur and calcium are almost uniformly distributed throughout the slab, and that in the slab without calcium treatment sulfur and manganese appear together periodically only at largely spaced positions. 相似文献
This study deals with optical properties of the anisotropic C3A-form. With an increase in SiO2 or Fe2O3 in the orthorhombic form of C3A dispersion formula varies from v > r to v < r with different optic planes (010 and 100 respectively), so that for a certain intermediate content the optic planes for colors at the extremes of the visible spectrum are crossed. In the case of the monoclinic phase dispersion takes place by a rotation of the optic plane around the acute bisectrix X(=c). The characteristic abnormal interference color of the anisotropic C3A can be explained by these various types of dispersion. 相似文献
The free radicals trapped in oriented nylon 6 filaments after γ-irradiation under vacuum at room temperature were studied by ESR spectroscopy. The ESR spectrum measured after irradiation gradually changed to a broad singlet spectrum with decrease in the intensity. The ESR spectrum consisted of radicals with different orientation effects with respect to the outer magnetic field, and saturation effects in reference to microwave power. The simulation of the ESR spectrum from a Gaussian function gave a better fit to the observed spectrum than the calculation from a Lorentzian function. From the resolution of the spectrum from a Gaussian function, the observed spectrum is generated from three kinds of radicals: The relative radical concentration for the first, second, and third radical is about 75%, 6%, and 19% of the total radical concentration, respectively. With regard to the stability of the radicals, the third radical shows a comparatively long lifetime. The first and second radicals show almost identical lifetime, and their concentrations reduce to about 40% of the initial value during the 2 days at room temperature. 相似文献
Adherent natural soils on fiber surfaces have been studied with the scanning electron microscope. The soils on the fiber surface
resemble oily soil. 相似文献
This paper describes the precision continuous path tracking control by using a dual-actuated single stage. First, fine-drive mechanism and the dynamic model of the entire drive system are described. In the simulation model, the dynamic characteristic of the dual-actuated stage is investigated to see whether it can provide precise motion by using dual control. Second, the fine motion controller is designed. Adjusting the control parameters, a positioning resolution of 20 nm and a bandwidth of 260 Hz were obtained. Third, the frequency responses of coarse and fine drives are experimentally investigated. After that, the dual controller is designed based on the investigated dynamics. Finally, whether coarse motion and fine motion could work complimentarily by the dual servo is examined in the experiments. By using the simultaneous dual controller, tracking errors were reduced sufficiently compared to the single coarse control. 相似文献
The quantitative measurement of a crystal bending effect is performed using low-order zone-axis convergent beam electron diffraction (CBED) patterns. Although the accuracy of the present method is inferior to that of the method of using split higher order Laue zone lines, this method enables us to estimate the crystal bending effect at a region very close to the interface and to easily judge whether the crystal bending effect results in a tensile bend or a compressive bend. As an application of the present method, the crystal bending effect at a region close to the SiGe/Si interface was measured. It was found that the crystal bending effect is due to a thin-foil relaxation of almost 0.3 degrees at a region that is approximately 10 nm away from the interface. 相似文献