大数据背景下智能监控在建筑施工安全管理中的应用研究

建筑行业作为基础产业,在我国国民经济中占据重要地位,但建筑施工安全事故屡见不鲜。在大数据背景下,如何提高建筑施工安全管理效果,制定出更加完善、系统的监管策略,是建筑行业实现高质量发展必须解决的重要问题。基于此,文章分析了大数据背景下,智能监控在建筑施工安全管理中的应用策略。

Efficient light-driven reductive amination of furfural to furfurylamine over ruthenium-cluster catalyst

Selective reductive amination of carbonyl compounds with high activity is very essential for the chemical and pharmaceutical industry,but scarcely successful paradigm was reported via efficient photocatalytic reactions.Herein,the ultrasmall Ru nanoclusters(~0.9 nm)were successfully fabricated over P25 support with positive charged Ru^(δ+)species at the interface.A new route was developed to achieve the furfural(FAL)to furfurylamine(FAM)by coupling the light-driven reductive amination and hydrogen transfer of ethanol over this type catalyst.Strikingly,the photocatalytic activity and selectivity are strongly dependent on the particle size and electronic structure of Ruthenium.The Ru^(δ+)species at the interface promote the formation of active imine intermediates;moreover,the Ru nanoclusters facilitate the separation efficiency of electrons and holes as well as accelerate the further hydrogenation of imine intermediates to product primary amines.In contrast Ru particles in larger nanometer size facilitate the formation of the furfuryl alcohol and excessive hydrogenation products.In addition,the coupling byproducts can be effectively inhibited via the construction of sub-nanocluster.This study offers a new path to produce the primary amines from biomass-derived carbonyl compounds over hybrid semiconductor/metal-clusters photocatalyst via light-driven tandem catalytic process.

银纳米线柔性电极的制备及电化学方法测定水中微量铜离子

以聚二甲基硅氧烷(Polydimethylsiloxane,PDMS)为柔性基底材料、银纳米线为导电层,制备了一种银纳米线柔性电极。此柔性电极具有良好的拉伸性和弯折性,可方便地改变电极的形状和大小。以其为工作电极,建立了方波溶出伏安法检测水中Cu^(2+)的方法。自制银纳米线柔性电极的微观表面均匀,平均电阻为1.03Ω,电化学性质优于商品金电极及商品银电极。考察了Bi3+浓度、支持电解质溶液及p H值、富集电位和富集时间对Cu^(2+)方波溶出伏安曲线峰电流的影响。结果表明,在Bi3+浓度为0.5 mg/L、0.1 mol/L酒石酸-酒石酸钠缓冲溶液(p H 4.8)为支持电解质、富集电位为0.6 V、富集时间为600 s的条件下,在-0.3~0.3 V范围内,Cu^(2+)的方波溶出伏安曲线峰形最尖锐,峰电流最高,检测最灵敏。在优化条件下,Cu^(2+)的线性检测范围为0.10~0.001 mg/L,检出限为9.27×10^(-5)mg/L。本方法检测Cu^(2+)速度快、灵敏度高、检测范围宽,可满足水样中Cu^(2+)的检测要求,同时为利用本方法检测水中的其它金属离子提供了参考和依据。自制银纳米线柔性电极具有良好的柔韧性以及生物相容性,在一些特殊场合的检测或即时检测中具有较大的应用潜力。

谷物联合收获机夹带损失监测方法研究进展

联合收获机作业过程中的粮食损失直接关系到农户的经济效益,掌握准确实时的谷物损失信息,不仅可为机手调整联合收获机工作参数、保证作业质量、提高作业效率提供直观依据,而且便于农户或有关政府部门跟踪、监测和统计各区域的收获损失。谷物损失主要包括割台损失、未脱损失、夹带损失、清洗损失和漏粮损失。其中夹带损失和清选损失在总损失中占有很大比例,因此有必要对其进行实时监控。国内对夹带损失监测方法的研究还处于理论和初步试验阶段,与国外的研究有所差距。提高夹带损失传感器的精度、可靠性和适应性是我国谷物联合收获机信息化发展过程中的难点和关键点。本文从夹带损失监测原理、传感器信号处理系统、传感器减振方法、夹带损失概率分布模型等方面综述了国内外谷物联合收获机夹带损失监测方法和装置的研究进展及其发展趋势。这些将有助于夹带损失传感器的不断改进和升级,为我国实现信息化收获作业奠定坚实的基础。

社交媒体积极自我呈现与生活满意度:自我效能感和乐商的中介作用

为了探讨社交媒体积极自我呈现对生活满意度的作用机制,采用社交媒体积极自我呈现量表、一般自我效能感量表、乐商量表和生活满意度量表对广东某高校412名在校生施测。结果显示,社交媒体积极自我呈现与一般自我效能感、乐商和生活满意度呈正相关;社交媒体积极自我呈现显著正向预测生活满意度,还可以通过一般自我效能感和乐商的中介作用来预测生活满意度。表明社交媒体积极自我呈现不仅能直接正向影响生活满意度,还能通过提高乐商和一般自我效能感产生间接影响。

Effect of the surface microstructure of arsenopyrite on the attachment of Sulfobacillus thermosulfidooxidans in the presence of dissolved As(Ⅲ)

Understanding bacterial adsorption and the evolution of biofilms on arsenopyrite with different surface structures is of great signific-ance to clarifying the mechanism of microbe-mineral interfacial interactions and the production of acidic mine drainage impacting the environ-ment.In this study,the attachment of Sulfobacillus thermosulfidooxidans cells and subsequent biofilm formation on arsenopyrite with different surface structures in the presence of dissolved As(Ⅲ)was studied.Arsenopyrite slices with a specific surface were obtained by electrochemic-al corrosion at 0.26 V.The scanning electronic microscopy-energy dispersion spectra analyses indicated that the arsenopyrite surface deficient in sulfur and iron obtained by electrochemical treatment was not favorable for the initial adsorption of bacteria,and the addition of As(Ⅲ)in-hibited the adsorption of microbial cells.Epifluorescence microscopy showed that the number of cells attaching to the arsenopyrite surface in-creased with time;however,biofilm formation was delayed significantly when As(Ⅲ)was added.

一种分布式的基于预留的多信道MAC协议

无线传感器网络(wireless sensor networks,WSNs)已经广泛应用于各个领域。许多领域利用了周期性数据汇聚,传感器节点周期性地产生数据包,通过一系列中继节点传输到汇聚节点。提出了一种分布式的基于预留的多信道MAC协议,称为R-MMAC协议,其中利用了预留机制和多信道通信机制,在多信道条件下,每个节点传输数据包时都将预留下一个数据包的传输,根据接收信号强度指示(received signal strength indication,RSSI)值选择自己的最佳信道进行预留。另外,还提出了针对预留时发生冲突的解决算法,利用信干噪比(signal to interference and noise ratio,SINR)和数据包接收率(packet reception rate,PRR)得到了预留的传输时间,从而降低了传感器节点到汇聚节点的传输时延和未来数据包的冲突概率。利用OMNET++5.3仿真工具对R-MMAC协议、X-MAC和EM-MAC协议进行了比较,结果表明R-MMAC协议实现了更低的端到端时延。

Public Agenda, Media Agenda and Policy Communication Process of Government Annual Reports:Based on the Survey in 19 Chinese Cities

Promoting direct policy communication between policy makers and the public is both an important function of government annual reports (GARs) and a key issue in democratic politics.According to this survey,conducted in 19 major cities in China,to promote the policy communication function of the GARs the government should make full use of changes in public policy communication habits and the convergence of public policy preferences in different groups while dealing with routine problems such as “public opinion deficits” and “being popular among the institutional staff but unnoticed the non-institutional staff.”

Co-thermal in-situ reduction of inorganic carbonates to reduce carbon-dioxide emission

Thermal decomposition of inorganic metal carbonates is the main path to prepare metal oxides;nonetheless,it is always accompanied by the emission of large amounts of CO_(2) as one of the gas products.This study reports a concept of co-thermal insitu reduction of inorganic carbonates by using the energy released by carbonate decomposition under pure hydrogen atmosphere,which reduces the decarboxylation temperature and significantly inhibits the CO_(2) emissions.A combination of hydrogen–deuterium exchange,isotope experiment,and density functional theory calculations demonstrates that the CO results from the selective cleavage of Ca–O bonds at the surface of CaCO_(3) via the direct hydrogenation mechanism at relatively low temperature.However,it undergoes the reverse water–gas shift reaction path at high temperature,i.e.,CO being produced by the reduction of CO_(2) released by the decomposition of carbonates.This study sheds light on the potential of green hydrogen technology for inorganic carbonate valorization toward high value-added products,which can facilitate the large-scale industrial applications.

面向B5G/6G大规模机器通信系统新型多址技术研究进展

大规模机器通信作为第五代移动通信系统的三大应用场景之一,也是支撑未来第四次工业革命的关键技术.其主要通过部署大量的机器设备,以实现智能型社会.由于低功耗要求,人们引入了免授权随机接入来减少设备与基站间的信令交互过程.加之无线电资源的匮乏,如何实现大规模机器设备的免授权随机接入成为挑战.在B5G以及6G中,这一挑战将变得尤为显著.因此有必要研究出一种行之有效的多址接入技术.串联扩频多址技术是一种实现大规模机器设备高效连接的新型非正交多址接入技术,并且能够以较低的复杂度实现高连接性和高可靠性.本文首先综述了大规模机器通信的特点及多址技术的研究现状.然后,介绍了串联扩频多址技术的收发机设计和性能权衡性分析.最后,介绍了串联扩频多址技术的研究进展和应用进展.

Spin-canting and weak ferromagnetism in two novel 1D alternating chains with single cis-end-to-end azido bridges

By combining trans-4-styrylprydine (tsp) with azide system, we obtained two rare 1D cis-EE-azido-bridged compounds of [M2(N3)4(tsp)4(H2O)2] [M = Mn (1), Co (2)]. The magnetic study reveals that metal ions are anti-ferromagnetically coupled by cis-EE-azido-bridges and they show weak ferromagnetism below 4.0 K (1) and 4.2 K (2) due to the spin-canting caused by asymmetric magnetic interaction.

Spin-canting and weak ferromagnetism in two novel 1D alternating chains with single cis-end-to-end azido bridges

By combining trans-4-styrylprydine (tsp) with azide system, we obtained two rare 1D cis-EE-azido-bridged compounds of [M2(N3)4(tsp)4(H2O)2] [M = Mn (1), Co (2)]. The magnetic study reveals that metal ions are anti-ferromagnetically coupled by cis-EE-azido-bridges and they show weak ferromagnetism below 4.0 K (1) and 4.2 K (2) due to the spin-canting caused by asymmetric magnetic interaction.