Soft magnetic Fe-B-P ultrafine particles with amorphous structure were prepared by aqueous reduction method with variable pH values. The microstructure, compositions and the soft magnetic properties of Fe-B-P submicron particles were investigated by using field emission scanning electron microscope (FE-SEM), X-Ray Diffraction (XRD), mössbauer spectrum (MS), inductively coupled plasma atomic emission spectroscopy (ICP-AES), vibrating sample magnetometer (VSM). The results showed that a series of Fe-B-P amorphous particles with the average particle size of 0.26~0.42 μm were obtained depending on the pH value of solution. As pH value increased, the contents of B and P increased, and the specific saturation magnetization of the Fe-B-P submicron particles decreased. Some electrons, transferred from p-shell of B atoms and P atoms to 3d-shell of Fe atom, resulted in the decrease of the number of unpaired electron, which in turn led to reduction of the average hyperfine magnetic field of the Fe-B-P particles and the decrease of the magnetic torque of Fe atoms. The relation between hyperfine magnetic field (Hhf) and the specific saturation magnetization was in accord with the Marshall’s equation. At the same time, the enhancement of the shielding effect on 4s electron orbital, i.e., the density of 4s electron reduced, leading to the increase of Isomer Shift.
Through simulation research on hydraulic characteristics of precast interlocking concrete blocks, the stress condition, overall stability, the effect of filling gravels into the holes of the blocks in the water flow during the flood period and the resistance parameters of the blocks were studied, a comprehensive analysis on the mechanical stability and the scour-resisting characteristics of the blocks was made, and then the requirement and the safety degree of the gravel filling were given. The experiment shows that compared with the surface protection of the conventional dyke projects, besides convenience for manufacture at low cost, this new type of protective revetment has such merits as higher anti-shear stress, better stability and permeability as well as improving ecological environment in river course.
Through hydraulic model test of Tianqiao hydropower station reinforcement project, the empirical equations of the surface flow pattern critical water depth were proposed and validated. Some factors affecting the change of the surface flow pattern critical water depth were analyzed. The results show that the critical water depth values will decrease gradually when the nose angle change from zero degree to fifteen degrees. Lengthening the protection-apron and flow expansion will result in the ascent of the critical water depth values, which will descend if the bed level is reduced or the nose height is increased.
Aimed at the representative project which is protected by the downstream sediment storage dam, three dimensional flow velocity field in local scour area around the separate bridge pier via physical model test was studied. The influences of shaping the eroded pit caused by the velocities in different directions were analyzed. The distribution results of flow velocity field in local scour pit near the pier protected by the sediment storage dam, deduced from the paper, will provide references for the defensive design of bridge projects.
Sudden sedimentation is an important subject for building ports in silt-sandy coast. It elaborates calculation methods detailed about three-layer deposition mode and analogy analysis mode. And they are used to predict the deposition in outer channel of Binzhou Port. Comparative results show that they are basically same on the distribution of sudden sedimentation, deposition thickness and volume along the channel. And it is larger from three-layer deposition mode than analogy analysis mode. The formal mode is propitious to project security. By analyzing the characteristics and applicability about two methods, basic law is obtained for sediment movement and predicting methods under strong wind in the outer channel of silt-sandy coast.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.