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51.
This paper discusses a multivariable array whose elements are multivariable homogeneous polynomials which may have missing terms in any of the variables. This array permits one to obtain conditions for the realizability of a driving-point function or a transfer function as a resistively terminated low-pass ladder network. By reac- tance transformations, other forms of ladder structures can be obtained. The case of cascade-separable ladder networks is discussed in detail.  相似文献   
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This paper discusses stress intensity factor (SIF) calculations for surface cracks in round bars subjected to combined torsion and bending loadings. Different crack aspect ratios, a/b, ranging from 0.0 to 1.2 and relative crack depths, a/D, ranging from 0.1 to 0.6 were considered. Since the loading was non-symmetrical for torsion loadings, a whole finite element model was constructed. Then, the individual and combined bending and torsion loadings were remotely applied to the model. The equivalent SIF method, F*EQ, was then used explicitly to combine the individual SIFs from the bending and torsion loadings. A comparison was then carried out with the combined SIF, F*FE, obtained using the finite element analysis (FEA) under similar loadings. It was found that the equivalent SIF method successfully predicted the combined SIF for Mode I. However, discrepancies between the results determined from the different approaches occurred when F III was involved. It was also noted that the predicted F*FE using FEA was higher than the F*EQ predicted through the equivalent SIF method due to the difference in crack face interactions.  相似文献   
54.
This paper introduces a new way of evaluating instructional strategies by using computers. Two basic theories, instructivism and constructivism, are discussed and critically evaluated in terms of their effectiveness in conceptual learning. Despite the current popularity of constructivism, the radical form of it is criticized in this paper. The advantages and limitations of these two approaches, especially the radical forms of constructivism, are outlined. After borrowing some ideas from other effective conceptual change models, an integrative model for conceptual learning (the Inventive Model) is introduced. Two versions of multimedia physics software are developed by the authors. The first version is based on the Inventive Model and the second version based on a radical constructivist model. The effectiveness of the Inventive Model was compared with the radical constructivist approach and conventional science instruction. Students' log files were analyzed to investigate the nature and the processes of the conceptual change. A conceptual test and a knowledge test were used to compare the groups. The quantitative results showed the superiority of the Inventive Model over the other models in conceptual learning and the superiority of conventional instruction in learning the basic knowledge. The qualitative analysis showed that only the Inventive Model lead to coherent conceptual learning. It was concluded that the process of conceptual change is gradual and continuous. Analysis of students' log files revealed no moments of dramatic change in students' conceptions.  相似文献   
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This study examined intra‐ and interindividual variations in parental legitimacy beliefs in a sample of 883 Arab refugee adolescents (Mage = 15.01 years, SD = 1.60), 277 Iraqis, 275 Syrians, and 331 Palestinians in Amman, Jordan. Confirmatory factor analyses showed distinct latent factors for moral–conventional, prudential, and personal legitimacy items. Older adolescents rated legitimacy lower for personal issues, but higher for prudential issues. Beliefs were associated with socioeconomic status (fathers' education, family size), particularly for personal issues, but were more pervasively associated with displacement‐related experiences. Greater war trauma was associated with less prudential legitimacy for all youth and more authority legitimacy over moral–conventional issues for Syrian youth. Greater hopefulness was associated with more authority legitimacy over all but personal issues.  相似文献   
57.
There is an ongoing debate over the activities of brands and companies in social media. Some researchers believe social media provide a unique opportunity for brands to foster their relationships with customers, while others believe the contrary. Taking the perspective of the brand community building plus the brand trust and loyalty literatures, our goal is to show how brand communities based on social media influence elements of the customer centric model (i.e., the relationships among focal customer and brand, product, company, and other customers) and brand loyalty. A survey-based empirical study with 441 respondents was conducted. The results of structural equation modeling show that brand communities established on social media have positive effects on customer/product, customer/brand, customer/company and customer/other customers relationships, which in turn have positive effects on brand trust, and trust has positive effects on brand loyalty. We find that brand trust has a fully mediating role in converting the effects of enhanced relationships in brand community to brand loyalty. The implications for marketing practice and future research are discussed.  相似文献   
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This study compared uses of U.S. television by foreign children residing in the U.S. and their American counterparts in light of theories of acculturation, cultivation, and uses and gratifications. Compared with U.S. children, foreign children: used television more for learning purposes, were relatively more interested in television programs, spent more time watching television, identified more frequently with television characters, and expressed stronger beliefs in the social reality portrayed by television.  相似文献   
59.
Corrosion is one of the main causes of deterioration in steel structures. Loss of thickness in flanges and web of corroded steel beams leads to reduction in section properties which can reduce the lateral torsional buckling capacity of the member. In this paper, thickness loss data were compiled from four samples of corrosion damaged I-beams removed from a petro-chemical plant. Visual examination of the four corroded beams showed that they were corroded uniformly. To improve the accuracy of the results, a large number of measurements for surface roughness were taken for each beam, totally 770 values to obtain the average thickness of flanges and web of each beam. The data was used to develop a corrosion decay model in order to calculate the percentage remaining lateral torsional buckling capacity of long and short span beams which are laterally unrestrained. To estimate the percentage of remaining lateral torsional buckling capacity in the corroded damaged I-beams, the readily available minimum curves for different types of universal beams in conj unction with information on the thickness loss were used. The results can be used by practicing engineers for better estimation on the service life of deteriorated steel structures.  相似文献   
60.
Surprisingly little is known about the relationship between perceived work success and information behavior. This study shows that holistic (versus organization-centric) information behavioral preferences are related to interaction and exchange oriented perceptions of the success of work. The findings were drawn from a partial least square structural equation modeling (PLS-SEM) based analysis of the survey data (N?=?305) collected from employees of a large multinational corporation. The findings suggest that holistic information behavior is more strongly related to social measures of success, whereas their association with quantitative measures tends to be lower. From the perspective of information behavior research, the findings suggest that holism seems to be a similar factor to, for instance, task complexity or personality, which influences human information behavior and, for instance, perceptions of relevance. From a practical perspective, the study suggests that the promotion of specific facets of measuring success and patterns of information behavior can be used to influence the orientation of working between centrifugality and openness.  相似文献   
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