现浇预应力混凝土箱梁的施工质量控制

现浇连续混凝土箱梁是桥梁上部构造中的重点部位,其施工质量的好坏不仅影响了整个桥梁的外观形象,且很大程度上决定了桥梁的使用寿命。现浇箱梁的混凝土浇筑施工质量控制要求高,在施工过程中,要防止因地基沉降、模板支架的弹性、非弹性变形以及外部荷载引起的混凝土裂缝等问题。以昆山市中环快速化改造工程的现浇预应力混凝土箱梁施工为例,论述混凝土浇筑过程中的质量控制及关键技术措施,可为相似工程提供参考。     

Fouling Resistance on Chemically Etched Hydrophobic Surfaces in Nucleate Pool Boiling

Chemical etching, liquid phase deposition, and dipping techniques were utilized to fabricate highly hydrophobic micro‐ and nanoscale coating surfaces on stainless‐steel substrates. Heat transfer and fouling characteristics on these surfaces in pool boiling of deionized water and CaSO₄ solution were studied. High roughness and hydrophobicity of coated surfaces were obtained on chemically etched substrates. Compared to the polished stainless‐steel surface, the chemically etched coating surface provided a three times enhanced nucleate boiling coefficient at high heat flux. Obvious decrease of CaSO₄ fouling resistance was obtained on chemically etched surfaces due to the higher roughness and hydrophobicity before the fouling resistance reaches the asymptotic value. Slightly high asymptotic fouling resistance was observed compared with coating surfaces without chemical etching of substrates.     

Synergistic effects of modified TiO2/multifunctionalized graphene oxide nanosheets as functional hybrid nanofiller in enhancing the interface compatibility of PLA/starch nanocomposites

The aim of this study is to investigate the synergistic effects of modified TiO₂/multifunctionalized graphene oxide nanosheets at different ratios on the interface compatibility between starch and poly(lactic acid) (PLA). To this end, silanylated nano-TiO₂ (MTiO₂, 1 and 2%) and alkylated maleic anhydride grafted graphene oxide (f-GO, 0.1, 0.2, and 0.4%) at different combinations are blended with the PLA-starch composites using solution blending technique. Then, the synergistic effects of MTiO₂ and f-GO on PLA/starch matrix are investigated in terms of the morphology, crystallinity, structural characterization, thermal stability, dynamic mechanical, and antiaging properties, and the related mechanisms. The Raman and Fourier transform infrared spectroscopy spectra verify the successful synthesis of the two modified nanofillers (f-GO and MTiO₂) and the formation of strong hydrogen bond within the PLA-starch nanocomposites. Due to the strong interfacial interaction and the synergistic effect from the combination of 1% MTiO₂ and 0.2% f-GO, obvious improvement was observed in PLA-starch versus other nanocomposites in terms of morphology, thermal stability, surface hydrophobicity, storage modulus, ultraviolet-shielding capacity, and aging-resistance. Furthermore, differential scanning calorimeter (DSC), isothermal crystallization kinetic, and X-ray diffraction analysis demonstrate that f-GO and the M-TiO₂ significantly synergize in enhancing the crystallization rate and crystallinity of PLA/starch matrix. These results provide novel insights for constructing high-performance nanocomposites and facilitate their applications in food packaging.     

Preloading using fill surcharge and prefabricated vertical drains for an airport

This paper presents the field measurements and analysis of a preloading project with the installation of prefabricated vertical drains (PVDs) in Wenzhou, China. At the site, PVDs were installed to a depth of 22?m from the ground surface with a spacing of 1.5?m in a triangular pattern. The preloading fill thickness was 6?m with a unit weight of approximately 18 kN/m³. After a total elapsed time of 310 days, approximately 3?m thick fill was removed. The measured preloading settlement was approximately 1.5?m. The measurements and analytical results indicated that the soil layer with PVD improvement reached almost 100% primary consolidation when part of the fill was removed. After partial unloading, the PVD-improved zone was in an over-consolidated state. After the runway was opened for traffic, a settlement increment of approximately 7?mm was monitored over a period of 11 months. Analysis indicated that the settlement was mainly due to the consolidation of soil layers below the PVD-improved zone and post-surcharge secondary consolidation of the PVD-improved zone. The values of the parameters related to PVD improvement were back-estimated from the field measurements. These findings can be used to guide the design of PVDs improvement along the east coast of China.     

福清核电厂基于堆外核仪表系统中间量程测量的动态刻棒试验

通过分析堆外核仪表系统的功率量程和中间量程的性能，使用堆外核仪表中间量程的测量信号进行动态刻棒试验数据验证。验证结果表明，基于堆外核仪表系统中间量程的动态刻棒试验可作为传统动态刻棒试验的一种手段，其测量误差在验收准则允许范围内，且无需进行本底电流测量即可减少动态刻棒测量时间。      

Erratum to: Effects of redox-active interlayer anions on the oxygen evolution reactivity of NiFe-layered double hydroxide nanosheets

Nano Research - The labels in Fig. 8 in the original version of this article were unfortunately misplaced. The corrected figure is as follow.     

典型实验房间空调气流组织监测方案设计研究

有效地通风和合理的气流组织对于改善室内空气品质,控制室内污染物浓度,对实现健康建筑、舒适性空调有着重要的意义。室内空调气流组织方式多种多样,对其效果的研究也很多,但是多集中在理论分析,而对气流组织效果的监测方面的研究较少,且监测方法没有一个完成的体系。首先对空调气流组织现场监测和评价方法进行分析,得知现场检测方法多以工程标准,只是对室内气流组织的应用效果进行评价,并不能完全反映气流组织的轨迹特征。其次,为了更好的反映不同时刻空调气流组织的特征,建立气流组织的监测方法,以5m×3m×2.8m的一个典型实验房间为例,利用计算模拟方法,分析不同气流组织形式下温度、风速等衰减特征,为室内气流组织现场智能监测测点布置提供依据。     

The development of semiconductor-ionic conductor composite electrolytes for fuel cells with symmetrical electrodes

Lowering the operational temperature of solid oxide fuel cells (SOFCs) is a vital research challenge for achieving broad commercialization of SOFCs. However, there is currently a lack of suitable electrolyte materials with sufficient ionic conductivity. In this review, the recent progress in semiconductor-ionic conductor composite strategies and related key technologies for low temperature SOFCs (LT-SOFCs) applications is highlighted, in particular, emphasizing the demonstration of such composite materials sandwiched between semiconductor electrodes in a symmetrical configuration that has delivered a potent solution. Despite the co-existence of electronic and ionic conduction in the composite membrane, no electronic short-circuiting was displayed, but rather an enhanced device power output was achieved. Here, the recent progresses in the development of SOFCs, from single-layer fuel cells, to two-phase semiconductor-ionic conductor membrane fuel cells with symmetrical electrodes, are discussed. This review will furnish researchers within the SOFC community and beyond with a broader understanding of the theory, development and significance of composite materials for LT-SOFCs.     

Parameter identification for Wiener-finite impulse response system with output data of missing completely at random mechanism and time delay

In this paper, the parameter estimation issue of Wiener system with random time delay and missing output data is studied. The linear part of Wiener system is described by Finite Impulse Response (FIR) model. The mathematical formula of the Expectation Maximum algorithm to identify Wiener-FIR system that contains the random time delay and the nonlinear output data in missing completely at random mechanism is derived, which is never considered before. To obtain the unmeasurable intermediate variable in Wiener-FIR system, the idea of auxiliary model is adopted. The time delay and system parameters can be estimated simultaneously by this method. Numerical example and the identification of water tank system example are carried out, the effectiveness of the algorithm is proved.