18世纪法国的现代先声——部雷建筑语言的来源和演变

艾蒂安-路易·部雷(étienne-Louis Boullée)是 18 世纪法国建筑界不容忽视的建筑师。部雷的建筑设计既折射了他的政治立场，也表现出建筑师为公民设计的热忱， 在 20 世纪中叶以后，又以其作品的先锋性和现代性启发了阿尔多·罗西等建筑师的创作和理论。欧美国家对部雷的研究已有一定的规模和深度，但目前关于部雷的中文出版物还极少。本文依据已公开的史料及相关历史背景，综述了有关研究者的观点，并在此基础上对部雷的创作动机及设计语言的来源作了进一步探索。对部雷作品的研究有助于理解 18 世纪的法国建筑史，对当代中国建筑师思考自身的社会责任及如何建构建筑的意义亦有启发。     

无降水条件下CRD暗挖工程洞内轻型井点止水措施的应用

北京地铁17号线盾构接收井横通道开挖施工中,发现下层导洞含水量大,虽采用全断面注浆残余水仍难以控制.对此将小型潜水泵接入轻型井点作为暗挖隧道止水措施,经计算根据隧道的最大涌水量确定了轻型井的各项参数;采用倾斜成孔等施工工艺,取得了良好的止水效果.     

广播电视技术与互联网技术融合的优势

随着互联网时代的发展,互联网技术逐渐延伸覆盖至各个领域.作为人们生产生活不可或缺的元素,广播电视与互联网技术不断融合,能优化传统业态,带给人们优质的服务体验.当前,如何在全新的发展形势下打破广播电视在传播信息、传播形式、传播媒介等方面的局限性,适应人们碎片化、快节奏生活的信息需求,积极融合互联网技术,成为媒体从业者亟待解决的课题.     

阻隔PET的合成及性能研究

聚对苯二甲酸乙二醇酯(PET)因其环保性能和低成本在食品包装领域应用越来越大,随着食品包装市场的不断升级,对包装材料也提出了更高的需求.近年,特别是在高阻隔包装材料领域需求量日益增多.PET本身具备一定阻隔性能属于中等阻隔材料,但在高阻隔领域其性能显得不足.为进一步提高PET的阻隔性能,同时保持其力学性能不受影响,选用反式富马酸为改性单体,通过利用其基团柔性、憎水性和不饱和键配合催化母粒后氧化消耗氧气,获得了高阻隔改性共聚酯,提升了PET阻隔能力和保证了其冲击强度等性能.力学性能测试表明:添加少量的富马酸可以提升PET冲击强度,但富马酸含量增加后冲击强度有所下降,拉伸强度随着富马酸含量增加反而降低.共聚酯的水蒸汽透过量和氧气透过率均较PET有较大提升,改性后能够适用于有高阻隔要求的食品包装领域.     

Large domain-wall currents in epitaxial Au/BiFeO3/SrRuO3 thin-film capacitors with modulated oxygen vacancy and wall densities

Large domain wall (DW) conductivity in an insulating ferroelectric plays an important role in the future nanosensors and nonvolatile memories. However, the wall current was usually too small to drive high-speed memory circuits and other agile nanodevices requiring high output-powers. Here, a large domain-wall current of 67.8 μA in a high on/off ratio of ~4460 was observed in an epitaxial Au/BiFeO₃/SrRuO₃ thin-film capacitor with the minimized oxygen vacancy concentration. The studies from read current-write voltage hysteresis loops and piezo-response force microscope images consistently showed remaining of partially unswitched domains after application of an opposite poling voltage that increased domain wall density and wall current greatly. A theoretical model was proposed to explain the large wall current. According to this model, the domain reversal occurs with the appearance of head-to-head and tail-to-tail 180° domain walls (DWs), resulting in the formation of highly conductive wall paths. As the applied voltage increased, the domain-wall number increased to enhance the on-state current, in agreement with the measurements of current-voltage curves. This work paves a way to modulate DW currents within epitaxial Au/BiFeO₃/SrRuO₃ thin-film capacitors through the optimization of both oxygen vacancy and domain wall densities to achieve large output powers of modern domain-wall nanodevices.     

Solution-Synthesized Multifunctional Janus Nanotree Microswimmer

Synthetic active matters are perfect model systems for non-equilibrium thermodynamics and of great potential for novel biomedical and environmental applications. However, most applications are limited by the complicated and low-yield preparation, while a scalable synthesis for highly functional microswimmers is highly desired. In this paper, an all-solution synthesis method is developed where the gold-loaded titania-silica nanotree can be produced as a multi-functional self-propulsion microswimmer. By applying light, heat, and electric field, the Janus nanotree demonstrated multi-mode self-propulsion, including photochemical self-electrophoresis by UV and visible light radiation, thermophoresis by near-infrared light radiation, and induced-charge electrophoresis under AC electric field. Due to the scalable synthesis, the Janus nanotree is further demonstrated as a high-efficiency, low-cost, active adsorbent for water decontamination, where the toxic mercury ions can be reclaimed with enhanced efficiency.     

英寸级少层MoS2薄膜的低温可控制备

大面积二硫化钼(MoS2)薄膜的可控制备是其走向应用的关键环节,尤其是少层及P型电导的MoS2,对于器件应用具有重要意义,但鲜有文献报道.本工作采用室温射频(RF)磁控溅射法,在玻璃衬底上制备了英寸级的少层MoS2薄膜,并经低温退火,实现了大面积较高质量的MoS2薄膜可控制备.原子力显微镜(AFM)、拉曼光谱(Raman)、X射线光电子能谱(XPS)、高分辨透射电子显微镜(HRTEM)和紫外可见吸收光谱(UV-vis)分析结果表明:所制得的大面积超薄薄膜为3层的多晶膜,厚度约2.2 nm,且均匀、平整、可控,薄膜结晶性好、稳定性高.使用同样的工艺在Si/SiO2基片上制备少层MoS2薄膜,并将其制成背栅场效应晶体管(TFT),电学表征表明该薄膜呈现P型导电特征,载流子迁移率为0.183 cm2·V-1·s-1.本工作提供了一种大面积少层MoS2薄膜的可控制备方法,而且制备温度低,工艺简单且兼容性强,易实现大规模工业化生产.     

Recent advances during CH4 dry reforming for syngas production: A mini review

Given the continuing issues of environment and energy, methane dry reforming for syngas production have sparked interest among researchers, but struggled with the process immaturity owing to catalyst deactivation. This review summarizes the recent advances in the development of efficient and stable catalysts with strong resistance to coking and metal sintering, including the application of novel materials, the assessment of advanced characterizations and the compatibility to improved reaction system. One feasible option is the crystalline oxide catalysts (perovskite, pyrochlore, spinel and LDHs), which feature a fine metal dispersion and surface confinement effect via a metal exsolution strategy and exhibit superior reactivity and stability. Some new materials (h-BN, clays and MOFs) also extend the option because of their unique morphology and microstructure. It also is elaborated that progresses were achieved in advanced characterizations application, leading to success in the establishment of reaction mechanisms and attributions to the formed robust catalysts. In addition, the perspective described the upgrade of reaction system to a higher reaction efficiency and milder reaction conditions. The combination of efficient reaction systems and robust catalysts paves a way for a scaling-up application of the process.     

Effect of cooking temperature on texture and flavour binding of braised sauce porcine skin

To investigate the effect of cooking temperature (55, 65, 75, 85 and 95 °C) on texture and flavour binding of braised sauce porcine skin (BSPS), sensory acceptance, microstructure and flavour-binding capacity were investigated during the processing of BSPS. Samples cooked at 85 and 95 °C showed better texture and aroma scores. Hardness and chewiness of BSPS were obviously improved at 85 and 95 °C than control group. Collagen structure was significantly destroyed over 85 °C. The porcine skin collagen heated at 85 and 95 °C showed relatively higher flavour-binding capacity than other samples. The improvement of texture of BSPS was mainly attributed to the degradation of collagen. Higher aroma scores of BSPS were related to intense binding abilities with aroma compounds at 85 and 95 °C. Cooking at 85 or 95 °C could be an optimal cooking temperature for BSPS.