为了确定AZ31镁合金轧制工艺参数,利用Gleeble-3500热模拟试验机进行热压缩试验以测试其热变形行为,并根据动态材料模型理论得到其热加工图.当变形温度为380~400℃、应变速率为3~12 s-1时,功率耗散效率大于30%,属于动态再结晶峰区;在该区域进行异步轧制变形退火处理后得到平均晶粒直径为2.3μm的细晶组织,抗拉强度为322.7 MPa,延伸率为19.6%.当应变速率大于15 s-1时,属于流变失稳区,250~300℃低温加工时合金的塑性显著降低,350~400℃高温加工时合金出现混晶组织

12.2 正交编码 12.2.1 正交编码的基本概念 12.2.2 阿达玛矩阵 12.2.3 沃尔什函数和沃尔什矩阵 12.3 伪随机序列 12.3.1 基本概念 12.3.2 m序列 【定理12.1】 【定理12.2】一个n级线性反馈移存器之相继状态具有周期性， 【定理12.3】若序列A = { ak }具有最长周期(p = 2n (x)产生的输出序列。而且，由定理12.2可知， 【定理12.4】一个n级移存器的特征多项式f (x)若为既约的， 由定理12.1可知，h(x)的次数比f (x)的低，而且现已假定f (x) 由定理12.4可以简单写出一个线性反馈移存器能产生m 现在我们讨论m序列的自相关函数。由12.2节互相关系数定 12.3.3 其他伪随机序列简介 12.4扩展频谱通信 12.5伪随机序列的其他应用 12.6 小结

§5—1 纯弯曲 §5—2 纯弯曲时的正应力 §5—3 横力弯曲时的正应力 M §5—4 弯曲切应力 §5—5提高弯曲强度的措施 §5—6开口薄壁杆件的切应力 弯曲中心

对采用转炉-RH精炼-连铸工艺生产的IF钢连铸板坯在不同浇铸阶段(开浇、正常、两炉交接及浇铸末期)的铸坯洁净度进行了较为细致地研究和对比分析.由于浇铸初期存在二次氧化及较大程度地增碳,开浇坯[C],[O]T,[N]含量远高于其他时间段的铸坯,并存在较大尺寸的簇群状Al2O3夹杂.正常坯夹杂主要为尺寸较小(≤ 30μm)的块状及少量簇群状Al2O3夹杂(≤ 40μm),交接坯及尾坯仍以较小尺寸的块状Al2O3夹杂为主,但存在极少量大于100μm的复合夹杂

1. 数制和脉冲信号 2. 基本门电路及其组合 3 . TTL 门电路 4 . C M O S 门电路 5. 逻辑代数 6. 组合逻辑电路的分析和设计 7. 加法器 8. 编码器 9. 译码器和数字显示 10. 数据分配器和数据选择器 11. 应用举例

The role of Mg in alloy/718 has been systematically investigated. Mg raises not only high temperature tensile and stress-rupture ductilities but also increases considerably smooth and notch stress-rupture life. Mg containing alloy 718M is free of stress-rupture notch sensitivity. Mg improves creep and fatigue interaction properties （LCF or cyclic stress rupture） at any grain size. The basic role of Mg is equilibrium segregation at grain boundaries which helps to change continuous grain beundary (5-Ni3Nb morphology to discrete globular form which has a retardation effect on intergranular fracture. Mg promotes the change from intergranular to transgranular fracture mode

第1节 引言 第2节 抽样定理 第3节 脉冲振幅调制 第4节 模划信号的量化 第5节 脉冲编码调制 第6节 增量调制 第7节 PCM与△M的性能比较 第9节 TDM和多路数字电话

Chapter 1 Introduction Chapter 2 Manufacture of 3D Fibre Preforms Chapter 3 Preform Consolidation Chapter 4 Micromechanics Models for Mechanical Properties Chapter 5 3D Woven Composites Chapter 6 Braided Composite Materials Chapter 7 Knitted Composite Materials Chapter 8 Stitched Composites Chapter 9 Z-Pinned Composites

Chapter 2 Water Chapter 3 Amino Acids, Peptides, and Proteins Chapter 4 The Three-Dimensional Structure of Proteins Chapter 5 Protein Function Chapter 6 Enzymes Chapter 8 Nucleotides and Nucleic Acids Chapter 9 DNA-Based Information Technologies Chapter 11 Biological Membranes and Transport Chapter 12 Biosignaling Chapter 13 Bioenergetics and Biochemical Reaction Types Chapter 14 Glycolysis, Gluconeogenesis, and the Pentose Chapter 16 The Citric Acid Cycle Chapter 17 Fatty Acid Catabolism Chapter 18 Amino Acid Oxidation and the Production of Urea Chapter 19 Oxidative Phosphorylation and Photophosphorylation Chapter 20 Carbohydrate Biosynthesis in Plants and Bacteria Chapter 22 Biosynthesis of Amino Acids, Nucleotides, and Related Molecules Chapter 24 Genes and Chromosomes Chapter 25 DNA Metabolism Chapter 26 RNA Metabolism Chapter 28 Regulation of Gene Expression

Part I Molecular Components of Cells 1 The Facts of Life: Chemistry Is the Logic of Biological Phenomena 2 Water: The Medium of Life 3 Thermodynamics of Biological Systems 4 Amino Acids and the Peptide Bond 5 Proteins: Their Primary Structure and Biological Functions 6 Proteins: Secondary, Tertiary, and Quaternary Structure 7 Carbohydrates and the Glycoconjugates of Cell Surfaces 8 Lipids 9 Membranes and Membrane Transport 10 Nucleotides and Nucleic Acids 11 Structure of Nucleic Acids 12 Recombinant DNA, Cloning, Chimeric Genes, and Synthetic Biology Part II Protein Dynamics 13 Enzymes—Kinetics and Specificity 14 Mechanisms of Enzyme Action 15 Enzyme Regulation 16 Molecular Motors Part III Metabolism and Its Regulation Part IV Information Transfer