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1.
The study is on two component blends of high density polyethylenes, having normal and ultra-high molecular weight. The polyethylenes were homogenized by two routes: in powder state or by rolling in melt, then pressed at temperatures in the range from 140°C to 220°C. Comparative studies showed that the way of homogenizing of the components does practically not affect the main mechanical properties of the blends when pressed at temperatures ≥ 160°C. Of special interest are the characteristics of those systems where ultra-high molecular weight polyethylene is the matrix component.  相似文献   
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In this paper,we address the need for better hands-on learning materials in computing education and the need for integrating mobile computing education into computing curricular.We propose an innovative learning approach that uses state-of-the-art mobile computing technologies and devices to design a highly accessible and real-world relevant hands-on labware for computing education.The labware employs a modular design such that the learning materials can both be combined together into a single course of mobile program development and be integrated into the related computing courses as building blocks.The labware will help students understand the concepts,improve their problem solving skills,and prepare them for the mobile computing industrial workforce.The pilot modules of the labware have been presented to undergraduate students and have received positive feedbacks.  相似文献   
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Human handedness, a marker for language lateralization in the brain, continues to attract great research interest. A widely reported but not universal finding is a greater male tendency toward left-handedness. Here the authors present a meta-analysis of k = 144 studies, totaling N = 1,787,629 participants, the results of which demonstrate that the sex difference is both significant and robust. The overall best estimate for the male to female odds ratio was 1.23 (95% confidence interval = 1.19, 1.27). The widespread observation of this sex difference is consistent with it being related to innate characteristics of sexual differentiation, and its observed magnitude places an important constraint on current theories of handedness. In addition, the size of the sex difference was significantly moderated by the way in which handedness was assessed (by writing hand or by other means), the location of testing, and the year of publication of the study, implicating additional influences on its development. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
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This paper presents the development of an optimal interval Newton method for systems of nonlinear equations. The context of solving such systems of equations is that of optimization of nonlinear mathematical programs. The modifications of the interval Newton method presented in this paper provide computationally effective enhancements to the general interval Newton method. The paper demonstrates the need to compute an optimal step length in the interval Newton method in order to guarantee the generation of a sequence of improving solutions. This method is referred to as the optimal Newton method and is implemented in multiple dimensions. Secondly, the paper demonstrates the use of the optimal interval Newton method as a feasible direction method to deal with non-negativity constraints. Also, included in this implementation is the use of a matrix decomposition technique to reduce the computational effort required to compute the Hessian inverse in the interval Newton method. The methods are demonstrated on several problems. Included in these problems are mathematical programs with perturbations in the problem coefficients. The numerical results clearly demonstrate the effectiveness and efficiency of these approaches.  相似文献   
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Contaminants in sediments: remobilisation and demobilisation   总被引:12,自引:0,他引:12  
In this study, the contaminated anoxic sediment of the Mulde reservoir (Saxony, Germany) was investigated. Several sediment cores were analysed for heavy metals and organic chemicals such as chlorobenzenes and DDTs. The comparison between anoxic and oxidised sediment cores showed the potential danger for heavy metal (Zn and Cd) remobilisation from sediment due to bioturbation or resuspension by flooding. Chemical sequential extraction was used to describe partitioning of heavy metals among different mineralogical components in the sediments. Results showed remobilisation of Zn and Cd from the sediments. The stable fraction (organic/sulfidic-bound) of Zn and Cd decreased from 10 to 3%, and from 35 to 5%, respectively. Simultaneously, the carbonate fraction increased from 3 to 12% for Cd and from 10 to 22% for Zn. Furthermore, the simulation of the diffusion of organic pollutants showed remobilisation of 1,4-dichlorobenzene. The results confirmed the necessity of sediment remediation in the reservoir. Capping seems to be a promising approach for a low-cost remediation.  相似文献   
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A systems prioritization methodology (SPM) is under development for the Waste Isolation Pilot Plant (WIPP). The SPM is based on a large numerical integration problem that must be repeatedly evaluated to determine compliance probabilities associated with different experimental programs and design modifications. Due to the complexity and computational cost of the underlying integration problem, the implementation of the SPM must be planned very carefully. This presentation describes a preliminary application of the SPM, designated SPM-l, performed to provide insights to facilitate the development and implementation of the methodology. Topics illustrated by SPM-1 include definition of probability spaces on which the SPM is based, use of Latin hypercube sampling and simple random sampling to integrate over different probability spaces, selection of mechanistic calculations to be performed, efficient use of the limited number of mechanistic calculations that can be performed, and assembly of many individual calculations into a complete analysis.  相似文献   
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A 20-year-old woman was admitted complaining of lower abdominal pain. Transabdominal ultrasound revealed a fluid collection in the pouch of Douglas and an irregularly shaped ovary with cystic lesions. Malignant cystic mass of the right ovary was highly suspected from the ultrasound findings. Transvaginal peritoneal centesis yielded a bloody fluid, but the pregnancy test was negative. On the third day of admission, menstruation began. MR examination performed four days after the initial onset of pain showed a subacute hematoma just adjacent to the right ovary, and segmental interruption of the right ovarian cortex. Based on these MR findings and the patient's history, subacute hemorrhage from the right ovarian corpus luteum was suspected, and this was confirmed with surgical exploration.  相似文献   
10.
In this paper the impact of taxation and arrangements for owner occupiers on household finance expenses are compared. The countries included are the Netherlands, Belgium, Denmark, France, the UK and (West) Germany. To achieve this comparison, taxation, subsidies and prevalent financing possibilities for owner occupiers are discussed. The comparison is made on a micro‐level: four representative fictitious owner occupiers in each country are taken into account. Conclusions are concerned firstly with a comparison among countries on the extent to which government intervention influences mortgage expenditure. Secondly, differences in effects of instruments on different income groups are described.  相似文献   
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