A volume-perturbation approach to the problem of Rayleigh wave scattering at a rectangular groove

The problem of scattering of Rayleigh waves at a rectangular groove is addressed. Grooves are known to excite bulk waves upon scattering and, hence, are potential sources (albeit secondary) in bulk-acoustic-wave (BAW) devices. The groove is formulated as a volume perturbation of the geometry. A modal method is used, and the results of Rayleigh wave reflection as well as bulk wave radiation are obtained and compared with the results available in the literature. The method is compared with the boundary perturbation formulation. The equivalence of the boundary perturbation method and the volume perturbation method is shown.     

Analysis of weakly guiding cladded acoustic fibers of hexagonal crystal symmetry

An approximate analysis of the weakly guiding cladded acoustic fiber consisting of a core and infinite thick cladding both with hexagonal crystal symmetry is presented. The crystalline Z axis is parallel to the fiber axis. Weak guidance conditions require that the stiffness constants of the core are slightly less than those of the cladding, and the density of the core and cladding are almost the same. Approximate dispersion and cutoff equations are derived for all pure guided modes. Dispersion curves of several lower-order guided torsional, radial-axial and flexural modes are evaluated using both exact and approximate formulas and they are in good agreement. A simple approximate dispersion equation for leaky (longitudinal-type) modes is also obtained.     

STUDY ON THE TENSILE FATIGUE DAMAGE OF QUASI—ISOTROPIC COMPOSITE LAMINATES

Quasi-isotropic. laminates have isotropic elastic properties in all in-plane directions. Therefore, this kind of laminate is widely used for structural elements. The simplest stacking sequence of quasi-isotropic laminates is [0/-60/60]s. When the direction of applied axial load to [0/-60/60]s laminate is inclined at a 30-degree angle, we have the other quasi-isotropic laminate [30/-30/90]s under axial load. The failure mechanisms of these two laminates are, however, entirely different from each other because these two laminates have different distribution of the interlaminar stresses. It was confirmed by tensile fatigue tests that the [0/-60/60]s laminate does not show any visible fatigue damage, but the [30/-30/90]s laminate develops edge-delamination during cyclic loading. The analytical results were in good agreement with the experimental results.     

用爆炸法消除残余应力的机理

本文着重分析用表面线状药包爆炸消除残余应力后的金属焊接接头结构变化的物理过程。     

低压反渗透和纳滤在水的净化和脱盐中的应用

研究了低压余ESPA-1膜和纳滤UPMN-P膜的工作特点。所使用的模拟溶液中含有不同浓度的NaCl、CaCl2、CsCl和SrCl2，OPMN-P膜显示出可以减少水的硬度，而ESPA-1膜既成功地从微碱水中去除了二价离子，又成功地去除了单价离子。研究结果已经被应用于正在开发的工业设备。     

园艺泥炭标准化问题

工业制造的园艺泥炭成了一种很普通的商品,此时,泥炭制品质量也获得了更大的关注。用户必须知道能以某种方式用于某种目的的制品的质量。另一方面,生产厂也必须知道用户想买哪些种类的制品。在一些国家,泥炭制品的销售很快受到了法令的控制。     

低能耗合成氨生产的联合能量回收系统

采用氨生产能量回收系统的现有装置,可以使每吨氨的能耗从8.4×10~6千卡降为7.0×10~6千卡。     

Fluor SOx净化工艺--为俄罗斯绿色环境开发的将SO2转化为元素硫的经济技术

Fluor公司开发的Fluor SO_2净化工艺具有广泛多样的工艺布局,可以通过经济的方式定制脱除烟气中的有害组成。该工艺几乎能去除全部SO_2并减少CO排放。Fluor SO_x净化工艺的主要步骤已在多套工业装置中得到成功的证实。除技术可行、经济合理之外,Fluor SO_x净化工艺不会产生任何有害副产物,也不会遇到与SO_3 有关的腐蚀问题。此外,该工艺生产高纯度可市售的元素硫。论述了Fluor SO_x净化工艺的特征、技术和成本优势、设计和操作的简易性以及实施的便利性。