Orthogonal Noise Annihilation for FTIR Spectroscopy in Fire Gas Analysis

Fourier Transformed Infrared (FTIR) spectroscopy may be used to monitor the evolved gases from a furniture calorimeter, but if concentration–time profiles are needed, compromises between spectral resolution, time resolution and sensitivity may have to be made, and the presence of significant noise levels limits the information that can be obtained from the infrared spectra. In this paper we demonstrate that the data may be satisfactorily treated by factor analysis to identify and reject factors attributable to noise. Subsequent reconstruction produces the original spectra with little or no noise and without significant loss of information. The reconstructed spectra were found to contain useful qualitative information even for the background spectra. By comparison, the traditional method of signal averaging for noise reduction not only leads to inferior spectra but also has a substantial disadvantage for fire gas monitoring because it leads to loss of information in poor time resolution, limiting the applicability of the FTIR spectroscopy to follow the combustion process.     

Elucidating the electro-catalytic oxidation of hydrazine over carbon nanotube-based transition metal single atom catalysts

Elucidating the reaction mechanism of hydrazine oxidation reaction (HzOR) over carbon-based catalysts is highly propitious for the rational design of novel electrocatalysts for HzOR. In present work, isolated first-row transition metal atoms have been coordinated with N atoms on the graphite layers of carbon nanotubes via a M-N₄-C configuration (MSA/CNT, M=Fe, Co and Ni). The HzOR over the three single atom catalysts follows a predominant 4-electron reaction pathway to emit N₂ and a negligible 1-electron pathway to emit trace of NH₃, while their electrocatalytic activity for HzOR is dominated by the absorption energy of N₂H₄ on them. Furthermore, FeSA/CNT reverses the passivation effect on Fe/C and shows superior performance than CoSA/CNT and NiSA/CNT with a recorded high mass activity for HzOR due to the higher electronic charge of Fe over Co and Ni in the M-N₄-C configuration and the lowest absorption energy of N₂H₄ on FeSA/CNT among the three MSA/CNT catalysts.

     

Shades of lightweight: supporting cross-generational communication through home messaging

Previous work suggests that older adults view communication with family as being worthy of time and dedication, and that they fail to understand the allure of lightweight contact. This paper presents findings from a field trial in which three generations of a family were linked through situated messaging devices, which, while designed to support lightweight messaging, also afford rich and expressive contact. Analysis suggests that communication via the devices provided a valuable additional dimension to the families’ existing practices, but that the type of messaging supported is best understood as one element in an amalgam of communication possibilities. Suggestions for complementary approaches are offered.     

脉冲CLVD+PIP联用工艺制备C/SiC复合材料

以液态聚碳硅烷(LPCS)为先驱体,采用脉冲化学液气相沉积(脉冲CLVD)与先驱体浸渍裂解(PIP)联用工艺制备了C/SiC复合材料。采用排煤油法测定了材料的密度,三点弯曲法测试材料的力学性能,采用扫描电子显微镜观察弯曲试样的断口形貌。结果表明:密度为1.76 g.cm-3的沉积试样在经过5轮PIP工艺处理后,材料的密度达到1.98 g.cm-3,抗弯强度达到321.9 MPa,和PIP工艺完全致密化的复合材料的密度及性能相当,但制备周期缩短到10天。材料中的PIP-SiC基体除了能填充纤维束间及层间的大孔隙,还能进一步填充纤维束内由于纤维束丝分布不均匀而在脉冲CLVD工艺过程中残留的大孔隙。     

Os(II) Based Green to Red Phosphors: A Great Prospect for Solution‐Processed,Highly Efficient Organic Light‐Emitting Diodes

Preparation and characterization of a new class of emissive Os(II) complexes ( 1 – 5 ) have been achieved using 3‐(thiazol‐2‐yl), 3‐(benzothiazol‐2‐yl), 3‐(imidazol‐2‐yl) and 3‐(benzimidazol‐2‐yl) azole chelates, together with the incorporation of one diphosphine ancillary for satisfying the octahedral coordination arrangement. The resulting Os(II) complexes, except for 5 , all show bright emission spanning visible region from green to saturated red, and their structural versus spectroscopic properties have been comprehended by absorption/emission together with computational approaches. Subsequently, a series of solution‐processed OLEDs using 1 – 4 as the dopant were successfully fabricated, demonstrating excellent device performances with external quantum efficiency (EQE) of 15%, current efficiency exceeding 48 cd/A, and power conversion efficiency up to 50 lm/W. Complex 4 is the only Os(II) based phosphor so far suitable for the fabrication of highly efficient green‐emitting OLEDs.     

机械作用对强碱三元乳状液稳定性的影响

油田强碱三元体系采出液运移和输送过程中产生乳化作用,造成输送能耗增加、油水分离难度增加.以室内模拟油水机械乳化方法,研究了水油体积比、乳化速率和乳化时间对强碱三元乳化体系乳状液稳定性的影响,并基于油相含水率和水相含油量对试验数据进行了分析.结果表明:水油体积比从9:1降低到1:4,乳状液的稳定性增强;乳化速率从10000 r/min增加到20000 r/min,静沉后油相含水率和水相含油量均增加;乳化时间从1 min增加到10 min,乳状液稳定性先增加后降低,乳化时间为3～5 min时乳状液稳定性最强;基于正交试验分析得出,乳化速率对乳状液稳定性的影响最大,说明采出体系流动过程中,管线变径、阀门等部位产生的扰动会导致采出液发生二次乳化.研究结果为现场判断乳化影响因素、采取治理措施提供了依据.     

超高温陶瓷及其复合材料的稀土改性研究进展

超高温陶瓷及其复合材料因具有耐超高温、轻质和抗氧化烧蚀等优点,目前已成为航空航天领域热结构材料研究的热点和前沿。基于稀土化合物在热障涂层等领域的优异性能和成功应用,研究人员将稀土化合物引入超高温陶瓷及其复合材料中,改善氧化层的结构和性质,以期解决超高温陶瓷基复合材料氧化层增长速度偏快和宽温域高低温循环氧化层易剥落等问题。本文综述了稀土改性超高温陶瓷及其复合材料的研究现状,分析探讨了改性机理,并展望了未来的研究发展方向。     

Exploring the Nature of Third Places and Local Social Ties in High-Density Areas: The Case of a Large Mixed-Use Complex

ABSTRACT

Evidence on the social sustainability of higher residential densities, as planned for in compact city policies, is mixed. Understanding the factors contributing to social sustainability in these contexts is key to compact cities' future success. This paper clarifies the concept of “third places”, spaces where people socialise and develop “weak tie” relationships, and appraises its relevance to social sustainability at high density. Findings around the form of third places and weak ties are presented from a mixed-use high-density complex in Sydney, Australia, facilitating the identification and development of spaces contributing to social sustainability at higher residential densities.