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51.
半正弦波冲击时瓦楞纸板破损边界研究   总被引:1,自引:0,他引:1  
根据瓦楞纸板平压静态模型,研究瓦楞纸板缓冲衬垫简化模型的包装材料在半正弦波激励下的冲击响应,建立动力学方程.应用四阶龙格-库塔数值法求解,从而得到瓦楞纸板包装系统的冲击谱和破损边界曲线,讨论了相关参数对它们的影响.结果表明,瓦楞纸板缓冲衬垫的系统参数(α、β、γ)对系统冲击谱和破损边界曲线有显著的影响。  相似文献   
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图像分形编码压缩率大且质量较高,但实时性不好,因此难以推广应用.提出使用GPU对编码进行加速的方案.以图像FW算法为基础,在CUDA规范下,使用GPU并行地对图像中所有的待编码子树同时进行最优父树搜索.实验表明,该文编码方案在保持原有算法图像解码质量的情况下,可将编码时间缩短至毫秒级,满足了实时性的要求.  相似文献   
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Mitochondrial carriers are membrane-embedded proteins consisting of a tripartite structure, a three-fold pseudo-symmetry, related sequences, and similar folding whose main function is to catalyze the transport of various metabolites, nucleotides, and coenzymes across the inner mitochondrial membrane. In this study, the evolutionary rate in vertebrates was screened at each of the approximately 50,000 nucleotides corresponding to the amino acids of the 53 human mitochondrial carriers. Using this information as a starting point, a scoring system was developed to quantify the evolutionary pressure acting on each site of the common mitochondrial carrier structure and estimate its functional or structural relevance. The degree of evolutionary selection varied greatly among all sites, but it was highly similar among the three symmetric positions in the tripartite structure, known as symmetry-related sites or triplets, suggesting that each triplet constitutes an evolutionary unit. Based on evolutionary selection, 111 structural sites (37 triplets) were found to be important. These sites play a key role in structure/function of mitochondrial carriers and are involved in either conformational changes (sites of the gates, proline–glycine levels, and aromatic belts) or in binding and specificity of the transported substrates (sites of the substrate-binding area in between the two gates). Furthermore, the evolutionary pressure analysis revealed that the matrix short helix sites underwent different degrees of selection with high inter-paralog variability. Evidence is presented that these sites form a new sequence motif in a subset of mitochondrial carriers, including the ADP/ATP translocator, and play a regulatory function by interacting with ligands and/or proteins of the mitochondrial matrix.  相似文献   
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对φ-截曲率为常数的Sasaki统计流形中的子流形建立关于广义标准δ-Casorati曲率的不等式, 并给出不等式中等号成立的条件.  相似文献   
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In this analysis, the classical problem of Hermann von Helmholtz's (1821–1894) Kantianism is explored from a particular vantage point, that to my knowledge, has not received the attention it deserves notwithstanding its possible key role in disentangling Helmholtz's relation to Kant's critical project. More particularly, we will focus on Helmholtz's critical engagement with Kant's concept of intuition [Anschauung] and (the related issue of) his dissatisfaction with Kant's doctrinal dualism. In doing so, it soon becomes clear that both (i) crucially mediated Helmholtz's idiosyncratic appropriation and criticism of (certain aspects of) Kant's critical project, and (ii) can be considered as a common denominator in a variety of issues that are usually addressed separately under the general header of (the problem of) Helmholtz's Kantianism. The perspective offered in this analysis can not only shed interesting new light on some interpretive issues that have become commonplace in discussions on Helmholtz's Kantianism, but also offers a particular way of connecting seemingly unrelated dimensions of Helmholtz's engagement with Kant's critical project (e.g. Helmholtz's views on causality and space). Furthermore, it amounts to the rather surprising conclusion that Helmholtz's most drastic revision of Kant's project pertains to his assumption of free will as a formal condition of experience and knowledge.  相似文献   
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There is ample empirical evidence that expert‐adjusted model forecasts can be improved. One way to potential improvement concerns providing various forms of feedback to the sales forecasters. It is also often recognized that the experts (forecasters) might not constitute a homogeneous group. This paper provides a data‐based methodology to discern latent clusters of forecasters, and applies it to a fully new large database with data on expert‐adjusted forecasts, model forecasts and realizations. For the data at hand, two clusters can clearly be identified. Next, the consequences of having clusters are discussed. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   
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经济系统发展动力结构优化模型与评价方法   总被引:2,自引:0,他引:2  
以产出型生产函数为基础构建了目标函数为人均增长速度最大的经济系统发展动力结构优化模型 ,给出了最优动力结构的特征和条件以及实际动力结构与最优动力结构之间差异程度的评价方法.  相似文献   
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