各向异性介质中周期性界面裂纹的弹塑性问题

应用富里叶积分变换方法将裂纹边值问题化为对偶积分方程组,再用定积分变换法将问题进一步化为奇异积分方程组,求得了双材料各向异性弹塑性介质中周期性界面裂纹反平面问题的封闭形式解,并作为特例讨论了各向同性双材料问题、各向异性单一材料问题及各向同性—各向异性双材料问题.结果表明:裂纹尖端前沿的塑性区尺寸、裂纹的张开位移(COD)均决定于两种材料流动极限中的较小者及裂纹的长度和相邻两裂纹的间距,此外,COD还与材料模量有关.     

非线性偶极-交换表面自旋波的包络孤立子解

介绍了非线性表面自旋波理论研究的新进展 ,并对前人的理论做了推广 ,针对具有非均匀交换各向异性的偶极 交换铁磁介质的非线性表面自旋波的性质和行为进行了较为系统的理论研究. The new progress in the theoretical investigation on nonlinear surface spin waves is reviewed, and the theory mentioned above is generalized. A relatively systematical investigation on the behaviors and properties of the nonlinear surface spin waves in dipole-exchange ferromagnetic media with inhomogeneous exchange anisotropy is developed.     

聚乙烯醇对锌镉铅溶出增敏作用及应用

在０．０５ｍｏｌ／Ｌ（ｐＨ６．５）乙二妥－盐酸介质中,聚乙烯醇－１２４ＰＶＡ－１２４）对锌,镉,铅的电位溶出有显著的增敏作用。当富集６０ｓ时,其检出限均达６．０μｇ／Ｌ,线性范围：锌０．６－３５μｇ／Ｌ,镉０．６－４５μｇ／Ｌ,铅０．６－５０μｇ／Ｌ。标准加入回收率为９２．４％－１１０％。ＲＳＤ（ｎ－４）〈７．０％。     

STRUCTURE AND M?SSBAUER STUDY OF NANOCRYSTALLINE Ni-Zn FERRITE

Ni_1-xZn_xFe₂O₄ (0.0≤x≤1.0) nanoparticles have been prepared by the polyvinyl alcohol (PVA) sol-gel method. The lattice parameter of Ni-Zn ferrite nanoparticles is larger than that of the bulk material. The variation of saturation magnetization (M_s) as a function of x has been studied. The M?ssbauer spectra of the samples at room temperature showed the presence of ultrafine particles, exhibiting superparamagnetic relaxation. At higher annealing temperature, the portion of the ferromagnetic ultrafine particles increased.     

Discussion on the SIF for points on border of elliptical flat crack inside infinite solid under uniform tension

Using the results of crack surface displacement field in Green-Sneddon’s solution[1] and coordinate transformation, this paper has derived an expression K₁(x₁,z₁,a) for SIF at any point and at any orientation on the border of elliptical flat crack inside infinite solid under uniform tension. As a complement of Irwin’s work[3], it is shown that for any pointed point on the elliptical border the SIF defined on normal plane takes the maximum value. And it should be pointed out that in some works some idea concerning Irvin’s contents is open to question. An expression K₁ in terms of polar angle which is more intuitional than centrifugal angle is proposed for SIF at any point on the elliptical border.     

γ'-Fe4N软磁复合材料的磁性及损耗特性

软磁复合材料在光伏逆变器、新能源汽车及充电桩等新兴电力电子行业的应用前景广阔.目前研究者们聚焦于开发新型软磁复合材料,达到匹配以SiC和GaN为主的第3代高频宽禁带半导体的目标.本文利用氨气氮化羰基铁粉制备得到高电阻率的γ’-Fe₄N,并证实其具备优异的软磁性能,对γ’-Fe₄N进行球磨处理使其成为静磁易面γ’-Fe₄N粉体,所获得的易面粉体与聚氨酯(PU)混合制成软磁复合材料.与未球磨静磁易面化处理的非易面γ’-Fe₄N复合材料相比,静磁易面γ’-Fe₄N软磁复合材料具有更高的磁导率,更低的功率损耗.与同类软磁复合材料相比,通过氮化工艺降低磁性铁颗粒内涡流效应,静磁易面γ’-Fe₄N软磁复合材料具有优异的高频软磁性能.静磁易面γ’-Fe₄N为软磁复合材料匹配第3代宽禁带半导体的高频应用提供了一种新思路.