摘要：In this article,the design of the hourglass truss sandwich structure is improved by optimizing the number of layers to enhance the compressive strength of both the core and the face sheet and then its mechanical performance. The hourglass truss structures characterized by three different numbers of layers are manufactured using an interlocking and vacuum brazing method. The effect of the layer number of the hourglass core panels on their out-of-plane compression and in-plane compression performance is investigated,and the results from calculations and experiments are in reasonable agreement. The results show that as the layer number of the hourglass core increases,the out-of-plane compressive strengths show little change,but their energy absorption properties are effectively increased. The in-plane compressive failure mechanism maps are constructed,and the specimens are designed to examine the local elastic and inelastic buckling failure modes of the face sheets. The results suggest that as the number of layers of the hourglass core increases,its maximum in-plane compressive load increases. The maximum in-plane compressive loads of the two-layer hourglass truss panels are 57%–70% higher than those of the single-layer panels. It can also be concluded that the out-of-plane and in-plane compression mechanical properties of the multilayer hourglass truss outperform those of the pyramidal truss. Furthermore,the number of layers of the hourglass core is optimized in consideration of both mechanical properties and fabrication cost.

摘要：A series of pyrrolo[2,1-c][1,4]benzodiazepine-3,11-dione derivatives was designed and synthesized,and their neuroprotective activity against SH-SY5Y cell injury induced by N-methyl-D-aspartic acid(NMDA)was *** the compounds showed significant neuroprotective effects,especially B16,which showed excellent performance and better activity than the positive control ifenprodil(B16:56.2%±0.6%;ifenprodil:41.0%±2.7%).Further investigation indicated that B16 could attenuate the Ca^(2+)influx induced by NMDA in SH-SY5Y cells and Western blotting also showed that B16 could attenuate the NR2B upregulation in SH-SY5Y cells induced by *** molecular docking results showed that compound B16 fitted in the binding pocket of NR2B-NMDAR well and could interact with binding sites of compounds 1 and 2 *** ADME/Tox prediction results suggested that compound B16 had good blood-brain barrier(BBB)permeability and the zero alert of Pan Assay Interference Structures(PAINS)indicated that B16 could not elicit false-positive *** results strongly suggest that B16 is a promising and effective candidate neuroprotective compound,and that NR2B-NMDAR is a potential target of B16.

摘要：The construction of interlocked topologies by metal-cation-template methods has been extensively ***,construction of these species using template-free chemical self-assembly methods is hard to rationally achieve due to the inherent unpredictability of self-assembly *** this work,a strategy to construct interlocked[2]catenanes by coordination-driven template-free self-assembly is demonstrated,whereby combining rigid bidentate ligands with large conjugated-πarea units and building blocks with appropriate lengths facilitated construction of interlocked[2]catenane *** rigid bidentate ligands,L1 and L2,were chosen to self-assemble with three dinuclear building blocks B1,B2 and ***,the successful construction of three[2]catenanes demonstrated the validity of the ***[2]catenanes are the simplest of all interlocked topologies,this motif is the basis for constructing more intricate *** successful strategy may therefore lead to construction of other,more intricate topologies in the future.

摘要：Empirical research is playing a significant role in software engineering （SE）, and it has been applied to evaluate software artifacts and technologies. There have been a great number of empirical research articles published recently. There is also a large research community in empirical software engineering （ESE）. In this paper, we identify both the overall landscape and detailed implementations of ESE, and investigate frequently applied empirical methods, targeted research purposes, used data sources, and applied data processing approaches and tools in ESE. The aim is to identify new trends and obtain interesting observations of empirical software engineering across different sub-fields of software engineering. We conduct a mapping study on 538 selected articles from January 2013 to November 2017, with four research questions. We observe that the trend of applying empirical methods in software engineering is continuously increasing and the most commonly applied methods are experiment, case study and survey. Moreover, open source projects are the most frequently used data sources. We also observe that most of researchers have paid attention to the validity and the possibility to replicate their studies. These observations are carefully analyzed and presented as carefully designed diagrams. We also reveal shortcomings and demanded knowledge/strategies in ESE and propose recommendations for researchers.

摘要：Liquid Droplet Radiator (LDR) system is regarded as a quite promising waste heat rejection system for aerospace engineering.A comprehensive review on the state-of-the-art of LDR system was carried *** thermal design considerations of crucial components such as working fluid,droplet generator and collector,intermediate heat exchanger,circulating pump and return pipe were *** state-of-the-art of existing mathematical models of radiation and evaporation characteristics of droplet layer from literatures were ***,thermal designs of three LDR systems were *** weight and required planform area between the rectangular and triangular LDR systems were respectively compared and the evaporation models for calculating the mass loss were *** on the review,some prospective studies of LDR system were put forward in this paper.

摘要：Polyl(lactide),PLA,suffers from bitleness and low heat deflection temperature(HDT),which limits its application as an engineering *** this work,poly(L-lactide)/poly(D-lactide)/ethylene-vinyl acetate glycidyl methacrylate random copolymer(PLLA/PDL A/EVM-GMA=1/1/x)composites were prepared by melt blending,and the in situ formed EVM-g PLA copolymers improved the compatibility between PLA and ***,the blends were subjected to a two-step annealing process during compression molding,*** annealing at 120℃ to rapidly form a certain amount of stereocomplex(sc)crystallites as nucleation sites,and then annealing at 200℃ to guide the formation of new *** differential scanning calorimetry(DSC)and wide angle X-ray dffrction(WAXD)measurements confirmed the formation of highly stereocomplexed PLA *** results showed that the PLLA/PDLA blend with 20 wt%of EVM-GMA had a notched impact strength up to 65 kJ/m2 and an elongation at break of 48%,while maintaining a tensile strength of 40 ***,dynamic mechanical analysis(DMA)and heat deflection tests showed that the PLA composite had an HDT up to 142℃ which is 90℃ higher than that of normal PLA *** electron microscopy(SEM)confirmed the fine dispersion of EVM-GMA particles,which facilitated to understand the toughening ***,the highly stereocomplexed PLA composites simultaneously exhibited excellent chemical and hydrolysis ***,these fascinating properties may extend the application range of sc PLA material as an engineering bioplastic.

摘要：This study proposes a new topology optimization solution providing designers with choices for feasible stiffener layouts inside large-scale containers of garbage trucks. Firstly, the mathematical expressions of loading conditions inside garbage containers are derived. Then, a growth-based layout optimization framework is built, taking inspiration from the morphology of plant ramifications. The principles of the highly effective but individual design rules of existent leaf venation layout problems are explored and transferred into analytical laws. Based on this, an evolutionary algorithm is developed to simulate the load-adapted growth of stiffener layouts, which provides an approximately homogeneous stress distribution along the surface of self-optimizing structures, Unlike the conventional methods, the new approach needs neither the densest ground structure nor the modification of the existing finite element programs, it is fast, easy to apply and nearly constraint free. Finally, a case study is provided showing how a large-scale container structure can be designed by this extremely intelligent CAD approach.

摘要：Marine biofouling is a major issue deteriorating the service performance and lifespan of marine *** development of a durable,long-term,and environment-friendly antifouling coating is therefore of significant importance but still a critical challenge in maritime ***,we developed a Cu-Ti composite antifouling coating with micron-sized alternating laminated-structure of Cu/Ti by plasma spraying of mechanically mixed Cu/Ti *** coating was designed to enable controlled release of Cu ions through galvanic dissolution of Cu laminates from the Cu/Ti micro-galvanic cell in aqueous *** showed that remarkable antifouling efficiency against bacterial survival and adhesion up to~100%was achieved for the Cu-Ti ***/Ti micro-galvanic cell was in-situ formed within Cu-Ti coating and responsible for its Cu ions *** successive dissolution of Cu laminates resulted in the formation of micro-channels under Ti laminates near surface,which contributed to controlled slow Cu ions release and self-polishing ***,environment-friendly antifouling capability and∼200%longer antifouling lifetime than that of the conventional organic antifouling coatings can be achieved for the Cu-Ti *** the other hand,as compared to the conventional organic antifouling coatings,the Cu-Ti composite coating presented much higher mechanical durability due to its strong adhesion strength,excellent mechanical properties,and two orders lower wear *** present laminated Cu-Ti coating exhibits combination of outstanding antifouling performance and high mechanical durability,which makes this coating very potentially candidates in marine antifouling application.

摘要：Although Alternate Parallel Receiver (APRX) could effectively improve the maximum demodulating rate of the receiver, its frequency domain processing module consumes a large amount of multiplication units when the number of parallel input channels is large, making it unsuitable for use on FPGA software defi ned radio platforms. This paper proposes an optimization scheme by introducing partitioned convolution and exploring the spectrum characteristic of the APRX input data, reducing the usage of multipliers greatly. After the optimization, the number of real multipliers used in the frequency-domain processing module of the 16-ary APRX is reduced from about 576 to 68, with little performance loss. This optimized APRX is fairly suitable for FPGA software defi ned radio platform applications.

摘要：Color tunable thin film polymer solar cells have demonstrated the potentials of a wide applications in photovoltaics printing, which is significant for ink pollution reduction and energy saving. This work presents a new effective approach to realize color-tuning photovoltaic cells with optical microcavity structures. Aluminum-doped zinc oxide is utilized as electron transport layer material. With its high electrical conductivity, the thickness tuning range can be quite large, which means the cavity length has a wide variation range. It thus provides sufficient space for optical thin film design to obtain multi colors. By the transfer matrix method, device reflection and absorption spectra are numerically investigated. Based on that, the optical principles for color tunability are explored. In further step, the relationship between device photovoltaics performance and reflective colors are also discussed. Finally, the color coordinates and luminosities are calculated. As results, the colors of the devices designed are capable to cover a relatively large region in Commission Internationale de l′Eclairage(CIE) 1931 x, y chromaticity diagram, which is available to be integrated into the advertisement poster boards, building wall printing and other display applications.