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991.
The near tip stress intensity factor KItip for an edge-crack in a Pb(ZrxTi1−x)O3 thin film was investigated by superposition of the applied stress intensity factor KIapp under a continuous laser irradiation and the shielding stress intensity factor ΔKI for 90° domain switching. Both KIapp and ΔKI were solved by the weight function method, and switching toughening was analyzed based on the small scale domain switching theory. Results show that KItip of the edge-crack in the thin film is significantly affected by the initial poling angle, and the edge-crack tip is toughened by the domain switching area with the increase of the initial poling angle. The methodology can predict the fracture toughening of Pb(ZrxTi1−x)O3 thin films quantitatively. 相似文献
992.
993.
Li Huijun; Lee Donghyuck; Pfeiffer Steven I.; Kamata Akihito; Kumtepe Alper T.; Rosado Javier 《Canadian Metallurgical Quarterly》2009,24(3):186
This study examined measurement invariance of the Gifted Rating Scales—School Form (GRS–S) across the United States, Puerto Rico, China, South Korea, and Turkey, using multigroup confirmatory factor analysis. A total of 1,817 students were rated by 287 teachers using either translated versions of GRS–S or the original English GRS–S. Results indicate a similar factor structure for the GRS–S across the five locations; six factors with each of the 72 items equivalently loaded to the same latent variable across groups. The metric invariance test and the factor variance and covariance invariance tests reveal that the patterns of factor loadings and the factor variances and covariances are invariant across the five groups. Moreover, the scalar invariance test indicates that item means are equivalent across the groups. These results suggest that the GRS–S has intercultural utility and can be similarly interpreted. Implications and limitations of the present research for gifted identification are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
994.
995.
财务状况综合评价的常用方法存在的指标信息重迭和主观赋权两点明显不足;因子分析法不仅能消除指标信息重叠的不利影响,而且能弥补主观赋权的不足;其方法的实际运用能取得较好的效果。 相似文献
996.
Tapio Salmi Henrik GrénmanJohan Wärnå Dmitry Yu. Murzin 《Chemical Engineering Research and Design》2013
Typical features of liquid–solid reactions were reviewed: reaction kinetics, mass transfer effects and particle morphology. It was concluded that classical liquid–solid models based on ideal, non-porous geometries (sphere, infinite cylinder, slab) cannot satisfactorily describe real reactive solid particles with various surface defects, such as cracks, craters and limited porosity. Typically a too low reaction order for the reactive solid is predicted by the classical models. The surface morphology can be revealed by electron microscopy, which gives inspiration to develop new mathematical models for reactive solids. 相似文献
997.
Succinic acid has been pertracted with TOA using free liquid membranes without or with 1‐octanol. The addition of the alcohol led to the increase of up to 2.8–3 times of the acid's initial and final mass flows. At the same time, the influence of 1‐octanol on the transport capacity of the pertraction system was negative, its addition inducing the accumulation of succinic acid into the liquid membrane. A mathematical model describing the acid accumulation inside the liquid membrane has been developed for pertraction systems without and with 1‐octanol and offers good concordance with the experimental data. © 2012 Canadian Society for Chemical Engineering 相似文献
998.
高锰酸盐指数是一个相对的条件性指标,其测定结果与标准溶液浓度、加热时间与温度、滴定条件、空白值等因素有关.全面总结分析了实际监测中各因素对CODMn测定的影响情况,并指出测定过程中应当注意的关键问题,对高锰酸盐指数的准确测定具有非常重要的意义. 相似文献
999.
Two-crack propagation paths in a ceramic/metal functionally graded material plate (FGP) under one-cycle temperature change of heating and cooling are considered. When the FGP is subjected to thermal shock, a single crack or multiple cracks often initiate on the ceramic surface during the cooling process and propagate in the FGP. Crack paths are influenced by the heating temperature conditions, a compositional profile of the FGP, the fracture toughness, interaction among multiple cracks, and so on. Transient thermal stresses are treated as a linear quasi-static thermoelastic problem for a plane-strain state. The crack paths are treated under fracture mechanics using the finite-element method. The effects of heating temperature conditions, a compositional profile of the FGP, the fracture toughness, and a crack space on the crack propagation pattern are discussed and are shown in figures. 相似文献
1000.
文中从项目设施过程中造价控制的具体做法出发,体现项目建设阶段的造价控制指导思想和基本原则,以期对同类建设工程能有所借鉴。 相似文献