万物互联时代背景下的居住空间模式探索

当前我们迈入了一个新科技、新信息时代——万物互联,生活状况、社会形态、社会秩序都发生了巨大转变,给予了事物变幻的可能性.居住区是一个城市的基本发展单元和治理单元,社区要根据科技的发展、生活模式的变化,打造人类可持续发展的人性化社区.为了适应这个多元的时代,提升社区居住空间的舒适性,文章基于复杂适应系统理论,通过对万物互联时代的特点及对社会生活的转变的分析,主要讨论万物互联时代的居住空间的发展,总结出复合、开放、多中心、共享、移动等空间状态.     

PdAg bimetallic electrocatalyst for highly selective reduction of CO2 with low COOH* formation energy and facile CO desorption

Nano Research - For electrocatalytic reduction of CO2 to CO, the stabilization of intermediate COOH* and the desorption of CO* are two key steps. Pd can easily stabilize COOH*, whereas the strong...     

Fracture behaviour of ceramic–metallic glass gradient transition coating

A new composite coating material of ceramic (Al₂O₃-40?wt% TiO₂)–metallic glass (Fe₅₆Cr₂₃Mo₁₃B₈) gradient transition coating was successfully prepared by atmospheric plasma spraying technology, and a new theory of laminar–columnar structure gradient transition synergistic enhancement effect was proposed. The microstructure and element distribution of the composite coating were studied by scanning electron microscopy (SEM), X-ray diffraction (XRD), and electron probe microanalysis (EPMA). The fracture toughness and fracture behaviour of the composite coating were analysed via micro-hardness and three-point bending (3PB) tests. The results showed that the stress release of the ceramic–metallic glass gradient transition coating was stable compared with that of the conventional gradient coating in the stage of acute deformation, and the coating exhibited better fracture toughness. Different areas of the ceramic–metallic glass gradient transition coating exhibited different fracture behaviours. Additionally, the ceramic layer was made of columnar crystals, and the metal–glass layer was lamellar. The laminar–columnar structure gradient transition synergistic enhancement effect improved the anti-crack growth and fracture toughness. This study provides a new and viable option for the improvement of thermal spraying ceramic composite coatings.     

修复方式对墩身混凝土裂缝修复效果的影响

采用环氧树脂、纯微生物修复液、一次性灌砂加微生物修复液和三次均段灌砂加微生物修复液四种修复方式修复墩身混凝土裂缝，然后对4种修复方式下试样进行修复速率、面积修复率、声时下降率、抗压强度、矿物组成和微观形貌等内容分析。试验结果表明：①环氧树脂修复裂缝效率最高，仅需两次，且面积修复率能达到100%，微生物参与修复的方式中一次性灌砂修复裂缝效率最高，修复次数为40次，面积修复率能达到96.38%；②环氧树脂修复后的混凝土试样抗压强度提升最大，修复后可达基准混凝土力学性能的88.90%；一次性灌砂加微生物修复裂缝效果比环氧树脂略差，但修复后可达到基准混凝土力学性能的87.17%，修复效果相当；③一次性灌砂加微生物修复液修复裂缝后声时下降率最大，平均声时下降率15.91%，比环氧树脂修复深度更深；但相比环氧树脂，混凝土裂缝经纯微生物修复液和三次均段灌砂加微生物修复液修复后存在较多的孔隙，经一次性灌砂加微生物修复液修复后均匀性较差。     

考虑用户出行成本预算的电力-交通耦合网络充电站定价策略

随着电动汽车的规模化发展,研究如何有效考虑用户的出行行为机理并制定合理的充电站充电价格,对电力-交通网络的协同优化调度具有重大意义。针对此问题,提出了考虑用户出行成本预算的电力-交通耦合网络充电站定价策略。首先,建立考虑出行成本预算的交通用户均衡模型,将均衡状态通过变分不等式进行等效描述,从而对电动汽车出行需求和充电行为进行刻画。其次,构建考虑功率削减的配电网二阶锥优化模型,将充电站定价问题转化为含有变分不等式约束的优化问题,并根据问题设计交替迭代算法和外梯度算法进行求解。最后,通过算例对所提模型和方法的有效性进行验证,结果表明了考虑出行成本预算对耦合网络充电定价的必要性。     

Fabrication of Cross‐Linked Anion Exchange Membranes Using a Pillar[5]arene Bearing Multiple Alkyl Bromide Head Groups as Cross‐Linker

A pillararene‐based macrocycle with up to 10 flexible chains bearing alkyl bromide head groups is synthesized and investigated for the first time as a multiarm cross‐linker for tertiary‐amine functionalized polyethersulfone. Different from any previously reported cross‐linker, this has a unique pillar‐shaped structure and abundant reactive sites to form multifunctional clusters in the conductive domain. This advantage enables cross‐linking to occur smoothly at the membrane‐casting stage and endows the cross‐linked membranes with improved performance. The cross‐linked anion exchange membranes are found to possess high conductivities and excellent alkaline stability. With a controllable swelling ratio of 19.5%, the maximum conductivity of a membrane can reach 155 mS cm^–1 at 80 °C. Due to its local high‐density cross‐linked structure, a delay in degradation kinetics under alkaline condition can be observed, and the loss of conductivity is <10% after 400 h of alkaline stability test at 80 °C.     

Boosting the Catalytic Performance by Confining Rich Carbon Atoms over Graphite Carbon Nitride Structure

In this study, the porous ultrathin graphitic carbon nitride (CN) nanosheets with rich C and nitrogen defects were prepared by one-step calcining the mixture of melamine and glucose (Glu) in air atmosphere (Glu-CN). Introducing simultaneously rich C atoms and nitrogen defects into CN structures continuously modulates the bandgaps from 2.67 to 1.81 eV of CN photocatalysts. Due to large surface area, more active sites, remarkably longer lifetime of charge carriers and adjustable band gap structure, the prepared ultrathin porous CN nanosheets show the enhanced photocatalytic performance for the degradation of methyl orange (MO) under visible light. The degradation efficiency of optimal CN nanosheet photocatalyst for MO is 5.75 times that of bulk CN. This work provides a facile and universal relevance approach to engineer the band structures of CN by introduction of rich C and porous morphology for high-performance photocatalytic, which can provide informative principles for the design of efficient photocatalysis systems for solar energy conversion.

Graphic Abstract

     

Residual stress and adhesion experiment on the capacitive MEMS power sensor based on GaAs MMIC process

This article investigates the failure due to collapse of the MEMS beams in capacitive MEMS power sensor based on GaAs MMIC process. Generally, the residual stress and adhesion are the main causes of the collapse of the MEMS beams. So, this article investigates the residual stress of the MEMS beams with an improved rotating technique. In addition, a resonant method has been used to investigate the adhesion of the MEMS beams. The measurement result shows that the buckling due to the residual stress is very small. Also, the finite analysis results show the rotating angle θ should be less than 0.12°. Thus, the collapse of the MEMS beams is mainly caused by adhesion.     

基于液质联用和分子对接技术对薄蒴草抗炎活性成分的筛选

目的:基于液质联用及分子对接技术筛选薄蒴草中的抗炎活性成分。方法:通过研究薄蒴草不同极性萃取部位对脂多糖（LPS）诱导的小鼠巨噬细胞RAW 264.7产生一氧化氮（NO）、肿瘤坏死因子-α（TNF-α）、白细胞介素-6（IL-6）的影响,筛选薄蒴草抗炎活性部位。通过高效液相色谱-质谱联用技术（high performance liquid chromatography-mass spectrometry,HPLC-MS）分析抗炎活性部位的化学成分。选择5个重要的炎症因子TNF-α、IL-6、白细胞介素-1β（IL-1β）、前列腺素E₂（PGE₂）、核转录因子-κB（NF-κB）分别与活性部位中的有效成分通过Autodock Vina软件进行分子对接。结果:体外抗炎实验结果显示薄蒴草的乙酸乙酯萃取部位具有一定的抗炎活性,与模型组相比在最高实验浓度75 μg/mL下对NO、TNF-α、IL-6的产生均有极显著抑制作用（P<0.01）,抑制率分别为63.53%、34.23%、34.58%;液质联用鉴定出11个化学成分,包括8个黄酮类成分芦丁、牡荆素、山奈酚、鼠李秦素、槲皮素、芹菜素、芹菜素-6-C-葡萄糖-8-C-木糖苷、槲皮苷和3个香豆素类成分伞形花内酯、7-甲氧基香豆素、5,7-二羟基香豆素;分子对接结果显示,与TNF-α、IL-6、IL-1β、PGE₂、NF-κB结合最好的成分分别是槲皮苷、山奈酚、芦丁、槲皮苷、牡荆素,结合能为?8.5、?7.8、?8.0、?7.2和?10.0 kcal/mol,均优于阳性对照地塞米松,说明这些成分与5个靶点具有较好的亲和力。结论:薄蒴草的乙酸乙酯萃取部位为抗炎活性部位,通过液质联用结合分子对接技术能快速、便捷地筛选出薄蒴草的抗炎活性成分。