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The multi-stages and narrow processing time window of injection molding process cause its complexity and difficulty for process control and product quality pledge. To explore these physical phenomena of molten polymer at nozzle location during the injection molding process, a T-shape extension nozzle for connecting the barrel and mold was designed in this paper. This T-shape extension nozzle could be easily installed and aligning the injection mechanism in the limited space of fixed plate without further modifying the injection molding machine or mold, and provide the space for installing sensors. It would be a useful diagnosing tool for parameters setting, verification, and stages validation. Two integrated high temperature ultrasonic transducers (HTUTs) were fabricated on both sides of diagnosing zone of T-shape extension nozzle for process monitoring at elevated temperature real-time, non-intrusively and non-destructively. The HTUTs on extension nozzle could be widely applied for diagnosing most of the polymer materials. The progression of the injection molding process, including mold close, injection, packing, screw back, metering and plasticating stages at the nozzle location, was clearly observed by ultrasonic signals. Ultrasonic amplitude and velocity could not only indicate these steps of process, but also correlate to the various injection pressure and flowing state of molten polymer in this paper. Therefore, the designed extension nozzle with HTUTs would provide a novel solution for diagnosis of injection molding process at nozzle location to distinguish the multi-stages of process and detect flowing state of material.

利用双时间格林函数讨论了S≥1/2情形的各向同性反铁磁性理论,对立方晶体得到了基态能量,次点阵自发磁矩及平行磁化率的表达式。所得结果在低温时与自旋波理论作了比较,在高温时与已有的结果比较接近。理论给出了S≥1/2时在整个温度范围内近似适用的统一结果。

The method of correlation function has been utilized to discuss the nonlinear effects in the ferromagnetic resonance at high power levels. For ordinary ferromagnetic crystals, the present theory includes the results of the semiclassical theory developed by H. Suhl as a classical limit. In the case of YIG doped with rare-earth ions, the frequency shift and the additional losses due to the rare-earth ions have been discussed. Besides, the threshold field of the so-called first order process with parallel pumping and the first and second order processes with perpendicular pumping have also been derived. The results obtained show that the rf critical magnetic field increases with the addition of rare-earth ions. In samples with small concentration of rare-earth ions, the influence on the threshold is attributed to the increase of the losses of spin waves. The temperature dependence and the anisotropy of the threshold field are entirely similar to those of the ferromagnetic resonance linewidth at low power level. The experimental results may be satisfactorily explained by the present theory.

The Lyons-Kaplan method is applied to the discussion of the change of spin configuration of a Bravias lattice in the presence of external magnetic field or magnetic anisotropy. It is shown that the antiferromagnetic structure transforms into ferromagnetic ones above a certain critical field and the formula for this critical field is derived. The stability of the corresponding spin configurations is also examined.

In this paper the influence of the scattering between spin waves on the ferromagnetic resonance absorption curves is discussed. The first order approximation of absorption curves and an exact expression for its 1-th moment are obtained.

By means of the algebraic method of the theory of angular momentum in quantum mechanics a detailed study is made for the model of s-f interaction of rare-eanth metals. A general form of the hamiltonian of s-f interaction is derived. By means of the method of the theory of perturbation in operator form the general expression for the effective hamiltonian of f-f interaction through s- f interaction was obtalned. Retaining terms to the second order of smallness, besides the isotropic exchange interaction the pseudo-dipole interaction is also obtained. On the basis of the results obtained, the magnetic crystalline anisotropy of the ferromagnetic phase of rare-earth metals wss discussed. Experimental facts that might be explalned by the results are indicated. (auth)