Event-triggered distributed receding horizon control for tracking and formation of homogeneous multi-agent systems

This paper proposes an event-triggered distributed receding horizon control (DRHC) approach for the formation and tracking problems of homogeneous multi-agent systems. For each agent, an event-triggering condition, based on assumed predictive information of the neighbours, is derived from stability analysis. Considering the uncertain deviation between the assumed and true predictive information, we design a time-varying compatibility constraint for the individual optimization problem. In the event-triggered DRHC algorithm, each agent solves the optimization problem and communicates with its neighbours only when the event-triggering condition is satisfied, so the communication and computation burden are reduced. Moreover, guarantees for the recursive feasibility and asymptotic stability of the overall system are proved. A simulation example is provided to illustrate effectiveness of the proposed approach.     

In-situ preparation of cross-linked hybrid anion exchange membrane of quaternized poly (styrene-b-isobutylene-b-styrene) covalently bonded with graphene

Introducing graphene into polymer matrix is an effective way to enhance performances of anion exchange membrane (AEM). However, utilizing the advantages of graphene by physical approach is limited due to the weak interface interaction between graphene and polymer matrix. Herein, we report an effective strategy to covalently bond graphene with polymer matrix to improve the interface interaction and further to improve the properties of AEM. A series of cross-linked quaternized graphene-based hybrid AEM were fabricated by covalently bonding poly (vinylbenzyl chloride) grafted graphene (GN-g-PVBC) copolymer with chloromethyl functionalized poly (styrene-b-isobutylene-b-styrene) (SIBS) through the cross-linker (N,N,N′,N′-tetramethyl-1,6-hexanediamine) by in-situ synthetic approach. The interface interaction between graphene and QSIBS is greatly enhanced according to micromorphology characterization of the hybrid membrane. The cross-linked quaternized hybrid AEM containing 0.55 wt% of GN-g-PVBC exhibits obviously improved dynamical mechanical properties (storage modulus: 418 MPa), ion conductivity (1.81 × 10² S cm^?1), methanol barrier property (5.19 × 10^?7 cm² s^?1), selectivity (3.49 × 10⁴ S s cm^?3) at 60 °C and especially a comparably excellent chemical stability to that of Nafion 115 due to the enhanced interface interaction between graphene and the polymer matrix.     

Preparation of mixed matrix composite membrane for hydrogen purification by incorporating ZIF-8 nanoparticles modified with tannic acid

The incompatibility between nanofillers and polymer, caused by the agglomeration of nanoparticles and their weak interaction with each other, is still a challenge to develop mixed matrix composite membrane. Herein, we introduced the ZIF-8-TA nanoparticles synthesized by in situ hydrophilic modification into the hydrophilic poly(vinylamine) (PVAm) matrix to prepare composite membranes for H₂ purification. The dispersion of ZIF-8 in water was improved by tannic acid modification, and the compatibility between ZIF-8 particles and PVAm matrix was enhanced by chemical crosslinking between the quinone groups in oxidized tannic acid (TA) and the amino groups in PVAm. Moreover, the compatibility between hydrophobic polydimethylsiloxane (PDMS) gutter layer and hydrophilic separation layer was achieved by the adhesion of TA-Fe³⁺ complex to the surface of PDMS layer during membrane preparation. The interlayer hydrophilic modification and the formation of separation layer were accomplished in one step, which simplified the preparation process. The experimental results indicated that when the TA addition used for modification was 0.5 g and the ZIF-8-TA_0.5 content in membrane was 12 wt%, the prepared membrane showed the best separation performance with the CO₂ permeance of 987 GPU and the CO₂/H₂ selectivity of 31, under the feed gas pressure of 0.12 MPa.     

Synthesis and Properties of Fumaric Copolymers as Potential Bitumen Modifiers

New copolymers of dioctyl fumarate (DOF) and styrene (S) were synthetized by radical polymerization and used to modify bitumen. The poly(dioctyl fumarate-co-styrene) copolymers, PFS, were characterized by ¹H-NMR and FTIR spectroscopies and size exclusion chromatography (SEC) in order to determine their monomer composition and weight average molecular weights, respectively. The polymer-bitumen blending conditions were optimized and the samples analyzed by different methodologies. Fluorescence microscopy, rotational viscosity and differential scanning calorimetry (DSC) were used to study the morphological changes of blends during their manufacturing and the rheological and thermal behavior, respectively. All modified bitumen (MB) exhibited higher viscosity than the based bitumen (BB) under studied conditions and this effect was more evident for the MB containing the higher molecular weight polymer. The addition of polymers to BB enhances the bitumen viscosity and thus increased the energy required for the flowing (activation energy calculated by Arrhenius equation). Thermal and morphological analysis showed that all MB exhibited good polymer- bitumen compatibility, which could be consider as a good starting point for a potential applications of this new material in road engineering.     

依坡就势,兼容并蓄——邵阳学院体育教学中心设计理念

高校体育建筑兼有文化性和时代性,它既要强调文化传统和校园文脉,又要体现体育建筑的时代特色。建筑设计应注重简洁、朴实和高品格,而不在于材料、装修的豪华及过分做作的造型。本案设计将定位于突出高校体育建筑特殊性以区别公共体育建筑,体现其实用性、兼容性与高效性,同时应节约土地和成本,充分利用建筑空间,营造宜人的校园氛围。     

RDP对SEBS/IFR共混体系性能的影响

向苯乙烯-乙烯/丁烯-苯乙烯嵌段共聚物(SEBS)/膨胀型阻燃剂(IFR)共混体系中加入间苯二酚双(二苯基)磷酸酯(RDP),通过扫描电镜、热失重分析仪和万能材料试验机等研究了RDP对SEBS/IFR共混体系相容性以及阻燃效率与力学性能的影响.当加入2％的RDP时,由于体系可能产生弱氢键,拉伸强度由6.665 MPa提高至6.773 MPa,但随着RDP含量的增加,体系的拉伸强度会明显下降,这主要由于RDP对于体系中SEBS的增塑作用.高压毛细管测试结果表明,当RDP含量大于6％时,体系黏度下降十分明显,利于体系加工流动性.随着RDP的加入,SEBS/IFR共混体系的热分解温度由最初的239℃提高至255℃并且趋于稳定,残炭率由13.28％提高至19.89％.扫描电镜测试结果显示,RDP可以通过“包覆”阻燃剂颗粒提高SEBS/IFR共混体系的相容性.     

便携式加固计算机结构综合防护设计研究

机箱作为电子设备正常稳定工作的基础设施,对电子元器件免于各种不良因素的影响具有重要保护作用。深入探讨一种下翻便携式紧凑型外设部件互连标准(CPCI)加固计算机的综合防护设计,主要从热设计、电磁兼容和抗振3个方面逐步介绍了该机的设计方案和思路,并通过试验进行验证。试验结果表明,该加固计算机质量轻,体积小,且具备优良的三防(防热、防磁和抗振)性能,能够在恶劣的环境中稳定可靠地运行。     

Use of tree pruning wastes for manufacturing of wood reinforced cement composites

Tree pruning wastes from six woody species, namely Acacia salicina, Conocarpus erectus, Ficus altissima, Leucaena glauca, Pithecellobium dulce and Tamarix aphylla, were used to manufacture high-quality wood reinforced cement composites (WRCCs). Hydrations experiments were conducted to screen the compatibility of the selected tree pruning wastes with cement. Additionally, various particle pretreatments and chemical additives were applied to enhance the compatibility of wood with cement. The best treatment for each species was selected and used to manufacture the WRCCs. The panels were produced under specific manufacturing variables and the mechanical properties and dimensional stability of the panels were determined. The results indicated that both board density and wood/cement (W/C) ratio had significant effects on the properties of WRCCs. With few exceptions, a W/C ratio of 1/2 and either 1200 kg m⁻³ or 1300 kg m⁻³ produced the optimal strength properties. The tree pruning wastes are suitable for use as raw materials in the manufacturing of WRCCs after pre-treatment of the wood particles with either cold or hot water and with addition 3% of CaCl₂, Al₂(SO₄)₃ or MgCl₂. Therefore, these wastes could be used as an alternative wood source for WRCCs.     

Another test of sensor lines on control panels

In this experiment all panels had four circular displays arranged in a square on a vertical surface and four controls aligned vertically to the right of the displays. Two panels had linkages between controls and displays which earlier research had shown to be compatible, the other two had incompatible linkages. Each of these four panels was tested with and without sensor lines showing the linkages between controls and displays. Ninety-six subjects each made 128 trials on one of the eight panels. A subject's task was to respond as quickly as possible by pushing the correct control to extinguish a light when it appeared in one of the displays. Sensor lines had no effect on performance with the compatible panels but impaired performance on the incompatible panels. The results also confirm again the potency of the compatibility principle: responses were faster and fewer errors were made when using the compatible panels.     

汽车电磁兼容技术及其发展趋势

汽车电子技术在汽车上的广泛应用带来了电磁干扰的问题,介绍了电磁干扰带来的危害和解决电磁兼容的重要性。从车载系统干扰源和外部环境干扰源两方面对汽车电磁环境进行分析,简介汽车电磁兼容性标准,并提出解决电磁兼容的方法和防止电磁干扰一系列措施。讨论了电动汽车的电磁抗干扰问题,最后,分析了汽车电磁兼容技术的未来发展趋势。