Helical milling of CFRP/Ti-6Al-4V stacks with varying machining parameters

The hole-making process in stack materials consisting of carbon fiber reinforced plastics(CFRP) and Ti-6Al-4V remains a critical challenge. In this paper, an experimental study on the helical milling of CFRP/Ti-6Al-4V stacks was conducted by using two different machining strategies. Helical milling strategyⅠ machines both materials with identical machining parameters, while machining strategyⅡ uses two sets of machining parameters to machine each material. Helical milling performance was evaluated by the following indicators: tool life, cutting forces, hole quality(including diameter deviation, roundness, roughness, and hole edge quality). The results demonstrate that helical milling strategy Ⅱ outperformed strategy Ⅰ, leading to longer tool life(up to 48 holes), smaller cutting forces and better hole quality with higher geometric accuracy and smoother surface finish(Ra≤ 0.58 μm for Ti-6Al-4V and Ra ≤ 0.81 μm for CFRP), eliminating the need for reaming or de-burring.     

组织·动力·成果:我国大学跨学科演进的三重维度与协同逻辑

本文从组织、动力、成果三重维度分析大学跨学科演进的历程,探讨跨学科的协同创新逻辑,有利于进一步强化大学跨学科活动的校内外认同,推动跨学科发展,促进协同创新中心建设和培育。     

Rumen fermentation and acetogen population changes in response to an exogenous acetogen TWA4 strain and Saccharomyces cerevisiae fermentation product

The presence of yeast cells could stimulate hydrogen utilization of acetogens and enhance acetogenesis. To understand the roles of acetogens in rumen fermentation, an in vitro rumen fermentation experiment was conducted with addition of acetogen strain (TWA4) and/or Saccharomyces cerevisiae fermentation product (XP). A 2×2 factorial design with two levels of TWA4 (0 or 2×10⁷ cells/ml) and XP (0 or 2 g/L) was performed. Volatile fatty acids (VFAs) were increased (P<0.05) in XP and TWA4XP, while methane was increased only in TWA4XP (P<0.05). The increase rate of microorganisms with formyltetrahydrofolate synthetase, especially acetogens, was higher than that of methanogens under all treatments. Lachnospiraceae was predominant in all acetogen communities, but without close acetyl-CoA synthase (ACS) amino acid sequences from cultured isolates. Low-Acetitomaculum ruminis-like ACS was predominant in all acetogen communities, while four unique phylotypes in XP treatment were all amino acid identified low-Eubacterium limosum-like acetogens. It differs to XP treatment that more low-A. ruminis-like and less low-E. limosum-like sequences were identified in TWA4 and TWA4XP treatments. Enhancing acetogenesis by supplementation with an acetogen strain and/or yeast cells may be an approach to mitigate methane, by targeting proper acetogens such as uncultured low-E. limosum-like acetogens.     

新兴技术企业产品创新与商业模式创新的组合对企业绩效的影响

根据创新理论、商业生态系统理论和社会资本理论构建了研究模型。分析了产品创新与商业模式创新的四种组合对企业绩效的影响以及社会资本的调节作用。采用174个新兴技术企业的样本,对模型进行了实证检验。研究发现,产品创新与商业模式创新的不同组合会有不同的绩效结果。理论和实证数据分析发现,混合策略比纯策略更加有利于提高企业绩效。更重要的是,研究发现不同类型社会关系对各类组合与企业绩效的关系有不同的调节作用。新兴技术企业应该选择混合策略而不是纯策略来提高绩效,应该根据不同的策略构建不同类型的社会关系。     

线粒体起源和蛋白含量进化

线粒体是真核生物重要的细胞器,为细胞提供大部分能量,同时也是活性氧(ROS)产生场所及细胞凋亡控制中心。线粒体来自与宿主共生的α-变形菌(α-Protobacteria),在形成细胞器的过程中α-变形菌蛋白组逐渐变小,将大部分遗传物质转移到核的同时与宿主建立了稳定的内共生关系。大多数现存真核生物的线粒体仍保留有少量来自α-变形菌的基因,其功能非常保守,仅编码线粒体蛋白合成相关的t RNA、r RNA、核糖体蛋白和氧化磷酸化复合物亚基蛋白。本文将从线粒体起源及蛋白含量进化进行综述。     

浅谈下一代互联网技术--网格技术

传统因特网实现了计算机硬件的连通，Web实现了网页的连通，而网格试图实现互联网上所有资源的全面连通，包括计算资源、存储资源、通信资源、软件资源、信息资源、知识资源等。网格作为一个集成的计算与资源环境，能够吸收各种计算资源，将它们转化成一种随处可得的、可靠的、标准的且相对经济的计算能力，其吸收的计算资源包括各种类型的计算机、网络通信能力、数据资料、仪器设备甚至有操作能力的人等各种相关资源。     

基于FIP的欧美在线隐私保护立法模式的比较研究

本文以美国联邦贸易委员会提出的公平信息原则（FP）为基础，对欧盟和美国在线隐私保护的立法模式及其相关法律进行比较分析；并在此基础上，对我国在线隐私保护的立法问题提出了作者的思考和建议。     

浅析高校计算机辅助教学存在问题及对策

教育要面向现代化，就必须实现教育手段的现代化，计算机是促进教育管理和教学手段现代化的最有效工具。各高等学校计算机基础课教学更是走在计算机辅助教学的前列，但从目前情况来看，各高校应用计算机辅助教学存在的问题还比较多，一些旧观念也需要更新，否则将影响计算机辅助教学的进一步开展和教学效果。     

低温冷冻干燥山楂果片的分析研究和营养评价

山楂果实营养非常丰富，且有特殊医疗保健功效。我们利用北方产区自然低温的特点，根据水的相变规律，提出了自然低温干燥加工山楂果片，使其成品的有效成分得以大量保存，远远高于晒干法等其它方法制成的果片。本文把这种冻干片与晒干片从几个方面进行化学分析对比。分析结果表明，冻干片中果胶、总酸、总糖、总黄酮以及维生素C\B1