以培育知识创新区为导向的城市更新策略——对杨浦建设“知识创新区”的规划思考

杨浦既是大学城区,也是传统的老工业区,早在十多年前即确立了以校区、园区、社区“三区联动”建设“知识创新区”的发展目标,但面对老工业区转型过程,始终难以弥合理想与现实的落差.围绕对知识创新区特质和形成机制的认识,提出“三区联动”的关键是从形式向内涵转换.聚焦创新主体,激活创新资源,提升城区人文内涵,通过空间结构体系重组等策略,构建城市更新的行动框架,推动杨浦向知识创新区的转型.     

碳纤维增强复合刹车材料的基体改性

刹车材料的成分和结构设计影响其性能及服役寿命。从碳纤维增强复合刹车材料的性能要求出发,对基体改性的应用现状、改性填料的引入方法进行系统详细的论述,并展望了新型复合刹车材料的发展思路及浆料法浸渗三维纤维预制体引入改性填料的发展方向。     

新时期城市总体规划实施评估的框架与方法——以武汉市城市总体规划(2010-2020年)实施评估为例

总体规划实施评估作为优化规划编制和实施机制的重要环节,是完善总体规划制度和促进总体规划改革的重要内容.在当前城市转型和规划改革双重背景下,评估工作具有复杂性.结合《武汉市城市总体规划 (2010-2020年)实施评估》实践,从终期评估特点出发,对评估的作用、内容框架、技术方法及若干趋势等进行了探讨,提出新时期总体规划实施评估要在规划内容、实施状况和实施效果评价的基础上,加强对城市问题和运行质量的诊断,关注实施过程,并从未来适应性出发做出趋势研判,为总体规划调整修编提供支撑,同时还要加强新方法新技术的运用,提高对城市空间特征和运行过程的解析能力.     

Cyclic Oxidation Behavior of the Ti–6Al–4V Alloy

The cyclic oxidation behavior of the Ti–6Al–4V alloy has been studied under heating and cooling conditions within a temperature range from 550 to 850 °C in air for up to 12 cycles. The mass changes, phase, surface morphologies, cross-sectional morphologies and element distribution of the oxide scales after cyclic oxidation were investigated using electronic microbalance, X-ray diffractometry, scanning electron microscopy and energy dispersive spectroscopy. The results show that the rate of oxidation was close to zero at 550 °C, obeyed parabolic and linear law at 650 and 850 °C, respectively, while at 750 °C, parabolic—linear law dominated. The double oxide scales formed on surface of the Ti–6Al–4V alloy consisted of an inner layer of TiO₂ and an outer layer of Al₂O₃, and the thickness of oxide scales increased with an increasing oxidation temperature. At 750 and 850 °C, the cyclic oxidation resistance deteriorated owing to the formation of voids, cracks and the spallation of the oxide scales.     

FCC催化剂中锑含量

工业上经常采用锑金属钝化剂防止FCC催化剂失活,但必须严格控制钝化剂的添加量,否则会起副作用,本文采用高温盐消解法处理FCC平衡剂,然后用火焰原子吸收光谱法测定催化剂中锑含量,考察了消解温度、消解时间、酸度等对测量结果的影响,优选出了最佳分析测试条件。所建方法简便、灵敏、准确,该方法回收率在95％～99％之间,变异系数小于2．5％,最小检出限为0．092mg／L。     

西班牙的伊比利亚火腿

本文介绍了西班牙伊比利亚火腿的猪种、猪的饲养方式、加工过程、近年来的新发展以及其风味的形成。     

宝浪油田煤层水泥封堵体系室内研究

针对宝浪油田高温(83～110℃)、高矿化度(30 000～250 000 mg/L),此外,部分井层因与煤层相距较近或油层与水层间夹层厚度小,导致大量注入水没有注入油层,而是进入了煤层。因此,选用波特兰水泥来封堵煤层,通过实验数据表明,向波特兰水泥中加入促凝剂A后,当浓度在0.10%～0.35%范围时,随着促凝剂浓度A的增大,候凝时间急剧减小,由68.0 h降低到17.5 h。而且煤颗粒越小,水泥胶结物的耐压能力就越高。经过聚合物交联体系封堵以后,水泥浆滤失量明显降低,只有12.8 mL,并且在15～35 h之间,随着时间的延长,水泥浆的稠度急剧上升。因此,通过总体评价所选水泥浆体系可以满足实际施工需要。     

In situ toughened two-phase B12(C,Si, B)3–SiC ceramics fabricated via liquid silicon infiltration

In situ toughened B₁₂(C, Si, B)₃–SiC ceramics were successfully fabricated via the liquid silicon infiltration process. Two types of B₁₂(C, Si, B)₃ phases, with high and low Si contents, respectively, and plate-like SiC particles were formed by the reaction between B₄C and Si. The in situ toughening mechanism involved two effects: the multiple crack deflections caused by the increased grain boundaries, and the pullout and rupture of a significant amount of plate-like SiC particles. Block ceramics with a high fracture toughness of 6.5 ± 0.5 MPa·m^1/2 were fabricated via the in situ toughening mechanism. A strong interface bond was present between the high- and low-B₄C-content layers in the laminated ceramics, which led to residual compressive stress inside the materials. As a result, the laminated structural design enhanced the fracture toughness to 7.5 ± 0.5 MPa·m^1/2.     

Oxidation resistance and thermal shock properties of self-healing SiCN/borosilicate glass-B4C-Al2O3 coatings for C/C aircraft brake materials

SiCN/borosilicate glass-B₄C-Al₂O₃ coating was deposited on carbon fiber-reinforced carbon matrix (C/C) brake materials to protect them from oxidation. Microstructural analysis revealed that the coating was dense and uniform. Fabricated coating showed excellent oxidation resistance and significantly low weight losses after oxidation in dry air for 10?h than SiCN/borosilicate glass-B₄C coated samples (ca. 0.12%, 0.51%, and 0.29% at 700, 800, and 900?°C, respectively). B₄C is believed to react with the oxygen diffused into the coating to produce B₂O₃, which could heal cracks of the coating and improve its self-sealing ability and oxidation resistance. The Al₂O₃ present in the outer glass layer is believed to inhibit volatilization of B₂O₃, thereby reducing weight losses in air. Fabricated coating also possessed excellent oxidation resistance under fresh and sea water conditions, with cracks and pores generated during oxidization process being effectively healed. Prepared coating materials showed excellent thermal shock resistances after 50 thermal shock cycles, with weight losses being as low as 0.23%.     

Microstructures and improved wear resistance of 3D needled C/SiC composites with graphite filler

Three-dimensional (3D) needled carbon/carbon (C/C) composites with a lowest porosity of 15.6% were achieved after 1 cycle of impregnation by phenolic resin slurry containing graphite filler, hot-pressing curing and pyrolysis. Carbon/silicon carbide (C/SiC) composites were obtained by liquid silicon infiltrating C/C composites. The aim was to incorporate cost effectiveness and excellent performance of C/SiC braking material. Using filler content not exceeding 30 wt% in the slurry promised undamaged C/C segments in C/SiC composites. The linear wear rate of C/SiC using 30 wt% filler was 0.33 μm side⁻¹ cycle⁻¹ and displayed a fourfold decrease; its weight wear rate was 2.46 mg side⁻¹ cycle⁻¹ and minus 171%, compared with the previously reported values of C/SiC without filler, at a braking velocity of 28 m/s. Its friction coefficients and friction stability coefficients appeared relative insensitive to changes in braking velocities and displayed higher values at high braking velocities compared with the previous values.