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51.
The main purpose of the study reported here was to investigate the relative importance of complexity of syllable structure and task differences in measuring phonological awareness in low-literacy adults. This study is a replication of a study with children conducted by S. A. Stahl and B. A. Murray (1994). Results indicated that the complexity of syllable structure did indeed better describe the construct of phonological awareness in low-literacy adults. At the same time, the authors also found some differences in the pattern of literacy acquisition for their Spanish adults in comparison with child literacy acquisition in English. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
52.
We present a fictitious domain decomposition method for the fast solution of acoustic scattering problems characterized by a partially axisymmetric sound‐hard scatterer. We apply this method to the solution of a mock‐up submarine problem, and highlight its computational advantages and intrinsic parallelism. A key component of our method is an original idea for addressing a Neumann boundary condition in the general framework of a fictitious domain method. This idea is applicable to many other linear partial differential equations besides the Helmholtz equation. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
53.
H. Oudadesse J. L. Irigaray Y. Barbotteau V. Brun Ph. Moretto 《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》2002,190(1-4):458-465
Bioactive glasses are used as coating biomaterials to facilitate anchorage of metallic prostheses implanted into the body. The aim of this work is to study the behavior of gel formed in contact with alloys and BVA and BVH bioactive glasses implanted. Cylinders of metallic implants composed by Ti, Al and V, are coated with bioactive glass. Three sheep were implanted for different time length: 3, 6 and 12 months in the femoral epiphysis. Results obtained with particle induced X-ray emission and scanning electron microscopy show that BVA coating induces a better contact between the metallic implant and bone. On the other hand, BVH coating prevents corrosion from the metallic implant. 相似文献
54.
In this paper, a unified method is presented: (i) to model delaminated stiffened laminated composite shells; (ii) for synthesising
accurate multiple post-buckling solution paths under compressive loading; and (iii) for predicting delamination growth. A
multi-domain modelling technique is used for modelling the delaminated stiffened shell structures. Error-free geometrically
nonlinear element formulations — a 2-noded curved stiffener element (BEAM2) and a 3-noded shell element (SHELL3) — are used
for the finite element analysis. An accurate and simple automated solution strategy based on Newton type iterations is used
for predicting the general geometrically nonlinear and postbuckling behaviour of structures. A simple method derived from
the 3-dimensionalJ-integral is used for computing the pointwise energy release rate at the delamination front in the plate/shell models. Finally,
the influence of post-buckling structural behaviour and the delamination growth on each other has been demonstrated. 相似文献
55.
建筑构件积木式CAD软件研究 总被引:4,自引:0,他引:4
西方以混凝土坝内廓道施工样图设计阶段为例,论述水工建筑件积木式CAD软件的必要性和积木模块CAD软件的具体实现方法。 相似文献
56.
Elias G. Abu‐Saba William M. McGinley Raymond C. Montgomery 《Canadian Metallurgical Quarterly》1991,4(4):347-354
As the manned exploration of space continues, many complex structural components are being developed to construct the orbital platforms that will be used to house communication hardware, personnel, and manufacturing complexes. These components are extremely flexible and complex in their behavior. There is a need for a simple method for determining the dynamic characteristics of these space structures with a minimum of effort. A mathematical model of one of these structural elements, an articulating truss beam, has been developed to predict its dynamic response. Assumptions of the force interaction between the beam elements and the joints have been made for using this model. Algorithms are provided to determine the flexibility matrix of the truss beam for use in the equation of motion. The natural frequencies obtained from using this method are compared with those obtained by the finite element method. An experimental procedure is planned to validate the results from the theoretical method. 相似文献
57.
Thomas J. R. Hughes Arif Masud Isaac Harari 《International journal for numerical methods in engineering》1995,38(19):3193-3210
Finite element methods for dynamic analysis employing elements with drilling degrees of freedom are presented. The formulation is based on a variational principle in which displacements and rotations are interpolated independently. The issue of zero masses corresponding to rotational degrees of freedom is addressed and techniques for defining consistent and lumped rotational mass matrices are presented. 相似文献
58.
Hoon C. Park Chahngmin Cho Sung W. Lee 《International journal for numerical methods in engineering》1995,38(24):4101-4122
The present paper describes an assumed strain finite element model with six degrees of freedom per node designed for geometrically non-linear shell analysis. An important feature of the present paper is the discussion on the spurious kinematic modes and the assumed strain field in the geometrically non-linear setting. The kinematics of deformation is described by using vector components in contrast to the conventional formulation which requires the use of trigonometric functions of rotational angles. Accordingly, converged solutions can be obtained for load or displacement increments that are much larger than possible with the conventional formulation with rotational angles. In addition, a detailed study of the spurious kinematic modes and the choice of assumed strain field reveals that the same assumed strain field can be used for both geometrically linear and non-linear cases to alleviate element locking while maintaining kinematic stability. It is strongly recommended that the element models, described in the present paper, be used instead of the conventional shell element models that employ rotational angles. 相似文献
59.
Tsai Jeanne L.; Miao Felicity F.; Seppala Emma; Fung Helene H.; Yeung Dannii Y. 《Canadian Metallurgical Quarterly》2007,92(6):1102
Previous studies have found that in American culture high-arousal positive states (HAP) such as excitement are valued more and low-arousal positive states (LAP) such as calm are valued less than they are in Chinese culture. What specific factors account for these differences? The authors predicted that when people and cultures aimed to influence others (i.e., assert personal needs and change others' behaviors to meet those needs), they would value HAP more and LAP less than when they aimed to adjust to others (i.e., suppress personal needs and change their own behaviors to meet others' needs). They test these predictions in 1 survey and 3 experimental studies. The findings suggest that within and across American and Chinese contexts, differences in ideal affect are due to specific interpersonal goals. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
60.