地质元及其在三轴压缩下的力学特性

本文提出了分析岩体结构的力学的各向异性的地质元概念。作者采用自己设计的三轴压缩装置,对完整结构、层状结构和碎裂结构地质元的力学性质进行了大量的研究。实例分析表明这一方法的可用性。     

所有制结构改革与制度创新

界定所有制结构内涵,提出了所有制逻辑结构,数量结构,整体结构,分体结构等新范畴;阐述了单一公有制的形成及其弊端;综述了公有制为主体的多元所有制结构形成的理论发展过程;提出了继续调整完善所有制结构的重点;剖析了所有制结构改革与制度创新的关系。     

主从结构系统的动态能量分析胶结构控制

从能量观点分析了主从系统在随机上的动力反应，说明了从属系统在地震作用下较主结构容易破坏的原因，并就其连接关系提出了改进建议，在此基础上，进一步分析了ＴＭＤ装置对主结构的耗能减震影响。     

地区交通运输结构优化研究

系统分析了地区交通运输结构优化的必要性与可行性，在提出合理的结构优化评价指标体系的基础上，建立了定性与定量方法相结合的地区交通运输结构优化模型，为交通运输复杂系统的结构优化提供了一种研究思路．     

论艺术设计人才的智能结构

艺术设计是一项复杂的创造性活动，而设计人才的智能在其中发挥着主导作用。面对复杂而多变的社会环境和经济环境，如何建构科学合理的智能结构对设计人才和施教者意义重大。本文从智能结构的基础系统、知识和能力系统及成就系统方面对设计人才的智能构成进行了较为详细的论述。     

公路教育结构研究

研究公路教育结构的主要目的，在于探求公路教育的层次(水平)结构、专业结构、类型结构、管理结构、地区布局结构等，使公路交通专门人才的培养和使用紧密地联系起来。     

钢筋混凝土结构裂缝与钢筋锈蚀的影响

通过对钢筋混凝土结构裂缝的成因和钢筋锈蚀的机理分析，深入研究探讨了不同的裂缝形态对钢筋锈蚀的相互关系，并提出了减少结构裂缝、提高结构耐久性的综合措施。     

Quantitative phase analysis of the calcium silicate slag as the residue of extracting alumina from high-alumina fly ash

Calcium silicate slag is the residue of process of pre-desilication alkali lime sintering applied in the high-alumina fly ash to extract the alumina. The quantitative phase analysis (QPA) of the calcium silicate slag has been performed by the Rietveld method based on the powder X-ray diffraction (XRD) with the aid of noncommercial software GSAS-EXPGUI. A known weight of crystalline internal standard (10% CaF₂) was added to the calcium silicate slag to calculate the fraction of amorphous phase and other crystalline phases on an absolute basis. Besides, the calcium silicate slag was characterized by X-ray fluorescence (XRF) and thermo gravimetric (TG) differential scanning calorimetry (DSC) to test the QPA results and investigate its other characters. Finally, the results show that the amorphous fraction is 17.5% (hereinafter, the percentages refer to the mass fraction), and the major crystalline phases detected in the calcium silicate slag consist of 23.5% Beta-Ca2SiO₄, 10.0% bredigite, 10.3% Ca₃Al₂O₆ (C₃A) and 21.6% CaCO₃.     

Effect of modified supplementary cementitious material on performance of mortar and concrete in marine environment

This study aims to explore the durability issues regarding chloride ion corrosion of concrete structures, and further investigates the modified supplementary cementitious material (MSCM) which acts as a significant enhancer of performance of mortar and concrete. The composition of MSCM includes mineral slag powder, fly ash and inhibitor. The microstructure, sulfate erosion resistance and electric flux of high-performance concrete are tested with MSCM, and the results show that the pore structure of concrete is improved significantly along with excellent electrochemical performance. It is observed that the substantiality of concrete after being mixed with 18% (mass fraction) MSCM is enhanced effectively. The sulfate resistance coefficient of concrete is found to be greater than 1.2, and the electric flux of concrete is less than 600C. These results have demonstrated that the MSCM possesses an excellent electrochemical performance and a wide applicative prospect in marine environment.     

Improvement the electrochemical performance of Li1.2Ni0.2Mn0.6O2 electrode with AlF3 added

Layered solid solution material Li_1.2Ni_0.2Mn_0.6O₂ is synthesized and the AlF₃ is added to improve the electrochemical performance. X-ray diffraction (XRD) results show that the Li_1.2Ni_0.2Mn_0.6O₂ samples exhibit layered characteristics. The AlF₃ additive is detected by transmission electron microscope (TEM) technology. The electrochemical tests show that Li_1.2Ni_0.2Mn_0.6O₂ electrode with AlF₃ added delivers better discharge capacity (240mA· h/g), first coulomb efficiency 79.2%, cyclic performance (capacity retention ratio of 100.6% after 50 cycles), and rate capacity (68mA · h/g at 10 capacity (C)) than the pristine sample. Electrochemical impedance spectroscopy (EIS) results show that the charge transfer resistance of Li_1.2Ni_0.2Mn_0.6O₂ electrode with AlF₃ added increases slower than that of pristine Li_1.2Ni_0.2Mn_0.6O₂ after cycling, which is responsible for better cyclic and rate performance.     

Grain refining mechanism of carbon inoculation on Mg-Al alloy

The processing parameters and refining mechanism of Mg-Al alloy treated with a newly developed carbon inoculant under different conditions were investigated experimentally in this work. Results show that the finest ??-Mg grain in AZ91D alloy can be obtained after processing at about 740°C, and the average grain size of ??-Mg grain decreases from about 180.4 to 85.6 ??m by adding mass fraction w _in = 1% inoculant into melt. However, no evident refinement was achieved with excessive inoculant for Mn-free Mg-9Al alloy. Scanning electron microscope (SEM) photo, energy dispersive spectroscopy (EDS) analysis on the Mn-contained intermediate phase and differential scanning calorimetry (DSC) results indicate that Mn element plays an important role in the heterogeneous nucleation of ??-Mg grain. In the early stage of solidification, Al-Mn-C compound particles formed on the surface of Al₄C₃ nano-particles should be the potential nuclei for primary ??-Mg and probably responsible for the grain refinement achieved in the carbon inoculation process.     

基于灰色系统理论的高寒盐沼泽区混凝土耐久性评估

依托青海省德香高速工程, 通过混凝土室内损伤试验, 分析了冻融干湿循环和盐腐蚀耦合作用下混凝土动弹性模量的演化过程与特征; 基于灰色系统理论, 建立了不同工况下混凝土相对动弹性模量GM (1, 1) 预测模型, 预测了2种损伤条件下3种配合比混凝土耐久年限; 依据室内损伤试验与灰色系统理论GM (1, 1) 模型预测结果分析了混凝土的组分, 研究了不同掺合料对混凝土耐久性的影响。研究结果表明: 混凝土耐久性GM (1, 1) 预测模型的相对误差在6%以内, 且后验差比值小于0.35, 小概率误差大于0.95, 预测精度较高; 不同使用环境对混凝土耐久性影响差异较大, 复合盐腐蚀-养护冻融循环的影响程度较复合盐腐蚀-浸泡冻融循环提高了42.8%~46.2%;掺加了粉煤灰、硅灰与膨胀剂的配合比Ⅲ的混凝土耐久性最好, 耐久年限较基准配合比混凝土提高了50%以上, 因此, 为了保证混凝土耐久性, 在类似地区工程实践中, 可参考配合比Ⅲ进行现场混凝土配比设计; 粉煤灰与矿渣同时使用将会生成钙矾石, 相比基准配合比, 不同配合比下混凝土耐久年限降低率均在50%以上, 严重损伤混凝土耐久性。      

孔结构对水泥混凝土抗冻性的影响

采用基于数字分析技术的测孔法及压汞法分别测试水泥混凝土的孔结构,研究水泥混凝土抗冻性与孔结构的关系,并对孔结构对混凝土冻融性能的影响加以分析。结果表明,掺入优质引气剞等外加剂可显著改善混凝土的孔结构,从而提高混凝土的抗冻耐久性。     

Improvements of elevated temperature strength and creep resistance of Mg-12Zn-4Al based alloy with calcium addition

A series of Mg-12Zn-4Al-0.3Mn (ZA124) based alloys with additions of calcium have been prepared and their microstructure and properties have been investigated. The results show that Mg-12Zn-4Al-0.3Mn alloy consists of the ??-Mg matrix and block quasicrystal and exhibits excellent creep resistance compared to commonly used AZ91 alloy. A small amount of calcium addition to the ZA124 based alloys increased the yield strenghth at both ambient and elevated temperatures as well as creep resistance, although the ductility decreased slightly. Microanalysis indicated that the addition of calcium decreased the quasicrystalline phase and caused the formation of some lamellar precipitates of Al₂Mg₅Zn₂ with orthorhombic crystal structure. This Ca-containing Al₂Mg₅Zn₂ phase with high stability straddled the grain boundaries and strengthened grain boundaries by inhibiting crack propagation during creep tests at elevated temperature.     

Purification effects of C2Cl6 on A00 aluminum

The effects of several fluxes on purification, microstructures and properties of A00 aluminum have been studied. The experimental results and analyses indicate that many cracks and large porosities exist in the surface film above the melt purified by C₂Cl₆ and that the film is floc and mostly composed of Al₂O₃ and pure aluminum, which carries many carbon particles and AlCl₃ not fully volatilized. And then over 50% (mass fraction) of the all-melting residue is pure aluminum, which is one of the major reasons for high melting loss. Moreover, because of a mass of gas bubbles and a state of seethe, there are many inclusions which size is under 10 ??m in the microstructure of A00 aluminum purified with C₂Cl₆ or fluxes containing C₂Cl₆. With this purifying method, the aluminum crystal grains are extended along the radius that was observed firstly and the average crystal size of A00 aluminum are about 100?C150 ??m. In addition, small size inclusions have little affected on tensile strength and micro inclusions under 10 ??m have little affected on elongation.     

Electronic structures and magneto-transport properties of co-based Heusler alloy based magneto-resistance junctions

A direct link between band structure and the ballistic transport property of full-Heusler alloys based Co₂ YZ/Al/Co₂ YZ trilayers (Y = Sc, Ti, V, Cr, Mn and Fe; Z = Al, Si and Ge) has been studied by firstprinciples calculations. It is found that the transport efficiency is determined primarily by three factors related to band structure: the shape of the band crossing Fermi energy E _F, the distance d of the two intersection points of Co₂ YZ and Al at E _F, and the absolute maximum of the energy lying in the E _F-crossing band, |E_max|. The transmission coefficient distribution patterns imply that the affected factor of magneto-resistance (MR) ratio is attributed to the band features around E _F. In general, an intuitively illustrated diagram is proposed to clarify the relationship between the probability of electron transition and the current magnitude.     

SAP内养生水泥混凝土综述

分析了超吸水性聚合物(SAP)的材料性能和SAP内养生混凝土配合比设计的关键参数，提出了内养生混凝土组成设计方法；从SAP吸释水行为和内养生混凝土水化特征角度，探讨了SAP内养生混凝土水分传输机制，综述了SAP内养生混凝土的收缩阻裂性能、力学性能和耐久性能；通过界面过渡区特征、水化产物和孔结构特征，探究了SAP内养生混凝土性能增强机理；总结了SAP内养生混凝土国内外工程应用情况，并展望了其未来的研究方向和应用前景。分析结果表明:SAP内养生原理为其本身的吸释水特性，但因SAP性能的差异和混凝土配合比等因素的不同，内养生水泥混凝土的各项性能有一定的差异性；SAP在渗透压和离子浓度的驱动下及时释水，补充混凝土内部水分丧失，降低早期水化热，并提升后期水化程度；SAP内养生混凝土的各项性能均受到其粒径、掺量和额外引水量的影响，在各参数均合适的条件下，SAP能够有效抑制混凝土的自收缩和干燥收缩，并增强混凝土的力学性能；SAP能够促进水化反应，生成更多的水化产物，填充混凝土的孔隙，增强混凝土的密实性，细化孔结构，切断连通孔隙，从而改善混凝土的抗冻、抗渗等耐久性能；SAP的再溶胀能力可阻塞混凝土裂缝，生成的CaCO₃等水化产物可使混凝土裂缝自愈合；SAP内养生作用能够增强水泥石与集料之间的黏结性，减少甚至消除界面过渡区微裂缝，提高界面过渡区强度；SAP内养生水泥混凝土在桥梁桥面整体化层、横隔梁、湿接缝、桥墩及隧道二次衬砌等部位已成功应用，抗裂效果优良。