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A method of designing beam-steerable patch antennas with wide stopband suppression is proposed in this article. The wide stopband suppression characteristic is realized by designing suitable parallel coupled lines and open-circuited stubs. The beam steering characteristic is achieved by using a driven patch and two pairs of metal walls vertically placed on both sides of the driven antenna. By controlling the different states of the switching PIN diodes loaded between metal walls, the stable beam steering characteristic can be obtained over the entire operating bandwidth. An experimental antenna is designed and manufactured to validate the approach. The beam steering angles of the simulation and measurement results are ±30°. Moreover, in the three proposed operating states, the out-of-band suppression from 2.6 GHz to 10 GHz is more than 16 dB. The proposed antenna can achieve the characteristic of both wide stopband suppression and beam steering. In addition, the proposed antenna is able to maintain good impedance characteristics during beam steering and maintain stable beam over the entire operating bandwidth. [ABSTRACT FROM AUTHOR]

Herein, the construction of 3-indolemalononitriles via base-promoted tandem decarboxylative propargylation/aromatization cascade of ethynyl benzoxazinanones with N,N -disubstituted aminomalononitriles has been developed. This protocol features mild reaction conditions, high efficiency and no need of transition metals. Various 3-indolemalononitriles can be obtained in moderate to excellent yields from readily available starting materials. More importantly, this method can be further applied to the synthesis of a wide range of indole products, paving the way for the development of new bioactive molecules. [Display omitted] Herein, the construction of 3-indolemalononitriles via base-promoted tandem decarboxylative propargylation/aromatization cascade of 4-ethynyl benzoxazinones with N,N -disubstituted aminomalononitriles has been developed. This protocol features mild reaction conditions, high efficiency and no need of transition metals. Various 3-indolemalononitriles can be obtained in moderate to excellent yields from readily available starting materials. More importantly, this method can be further applied to the synthesis of a wide range of complex indole products. [ABSTRACT FROM AUTHOR]

2D coordination complexes [Cd(1,3-pbpa)(1,3-PDA)] n , 1 and [Cd(1,3-pbpa)(OBA)·2H 2 O] n , 2 , exhibit rare {84·122}{8}2-2,4L2 topology, and [Cd(1,3-pbpa)(1,4-BDC)(H 2 O)·EtOH·H 2 O] n , 3 shows a new topology having point symbol {12}{4·125}{4}. Desolvated product of 2 exhibits a better H 2 and CO 2 sorption compared to the activated product of 1 , indicating the effect of ligand type on the adsorption properties of 2D complexes. Solvothermal reactions of Cd(CH 3 COO) 2 and 2,2′-(1,3-phenylene)-bis(N-pyridin-3-yl)acetamide (1,3-pbpa) with 1,3-phenylenediacetic acid (1,3-H 2 PDA), 4,4′-oxybis(benzoic acid) (4,4′-H 2 OBA) and 1,4-benzenedicarboxylic acid (1,4-H 2 BDC) afforded [Cd(1,3-pbpa)(1,3-PDA)] n , 1 , [Cd(1,3-pbpa)(OBA)·2H 2 O] n , 2 , and [Cd(1,3-pbpa)(1,4-BDC)(H 2 O)·EtOH·H 2 O] n , 3 , respectively, which were structurally characterized as two-dimensional (2D) coordination polymers. Complexes 1 and 2 show the rare {84·122}{8}2-2,4L2 topology, whereas complex 3 adopts a new topology with a point symbol of {12}{4·125}{4}, which can be further simplified as the 44- sql topology and the 63- hcb topology, respectively. Desolvated product of 2 shows a moderate uptake of CO 2 and a good selectivity over N 2 , which also exhibits a better H 2 and CO 2 sorption compared to the activated product of 1 , indicating the effect of ligand type on the adsorption properties of 2D complexes with the 44- sql topology. Thermal gravimetric analysis (TGA) and the solid state luminescence properties of 1 – 3 have also been investigated. [ABSTRACT FROM AUTHOR]

This paper proposes a duplex dual circularly polarized antenna, using four half-Vivaldi antennas to form a sequential rotation array, which can generate circular polarization by sequential feeding. A mental cavity and half of a Vivaldi antenna form a new Vivaldi antenna. The Vivaldi antenna has broadband characteristics to cover the uplink and downlink bands and is compact with an area of 0. 69 λ c × 0. 69 λ c . To achieve duplex dual circular polarization, a feeding network that can sequentially output + 90 ° and − 90 ° is designed. The feeding network, which contains two broadband power dividers, two directional couplers and two phase-shifters, generates the sequential feeding signals for sequential rotation group array with equal amplitude and ± 90 ° phase difference. Both the impedance bandwidth and the 3 dB axial ratio bandwidth of the transmitter and receiver can cover the band of 10–15 GHz. The gain of the antenna is higher than 5.75 dBi. The isolation between the receive and the transmit ports can reach 25.49 dB or higher in the uplink band. [ABSTRACT FROM AUTHOR]

Forest canopies play a vital role in scavenging airborne semi-volatile organic compounds. The present study measured polycyclic aromatic hydrocarbons (PAHs) in the understory air (at two heights), foliage, and litterfall in a subtropical rainforest (the Dinghushan mountain) in southern China. ∑ 17 PAH concentrations in the air ranged from 2.75 to 44.0 ng/m3 (mean = 8.91 ng/m3), showing a spatial variation depending on the forest canopy coverage. Vertical distributions of the understory air concentrations also indicated PAH inputs from the above-canopy air. The concentrations of PAHs in fresh litter (with a mean of 261 ± 163 ng/g dry weight (dw)) were slightly lower than those in the foliage (362 ± 291 ng/g dw). Unlike the stable air PAH concentrations for most of the time of the year, the temporal variations of foliage and litter concentrations were remarkable but generally similar. Higher or comparable leaf/litter-air partition coefficients (K LA) in fresh litter compared with living K LA in leaves suggest that the forest litter layer is an efficient storage media for PAHs. Degradation of three-ring PAHs in litter under the field conditions follows first-order kinetics (R2 = 0.81), while the degradation is moderate for four-ring PAHs and insignificant for five- and six-ring PAHs. The yearly net cumulative deposition of PAHs through forest litterfall in the whole Dinghushan forest area over the sampling year was about 1.1 kg, 46% of the initial deposition (2.4 kg). This spatial variations study provides the results of in-field degradation of litter PAHs and makes a quantitative assessment of the litter deposition of PAHs, deducing their residence dynamics in the litter layer in a subtropical rainforest. [Display omitted] • ∑ 17 PAH concentrations in the understory air depended on the forest communities. • Temporal variations of PAH levels in foliage and litter were generally similar. • Air-litter K LA suggests the forest litter layer is an efficient storage media of PAHs. • Degradation of three-ring PAHs in the litter follows first order kinetics. • An estimated deposition fluxes of 270 μg/m2·yr PAHs deposit to the forest ground via fresh litterfall. [ABSTRACT FROM AUTHOR]

This paper presents results from numerical studies on the effect of critical factors governing the axial compression mechanical properties on square cross-section concrete-encased concrete filled steel tubular (CFST) stub columns after fire exposure. A validated three dimensional finite element model is applied for evaluating axial compression mechanical properties of concrete-encased CFST stub columns after fire exposure under different factors. The factors varied in the parametric study include fire exposure time, steel tube area ratio, longitudinal bar ratio, compressive strength of concrete, yield strength of steel tube, and sectional core area ratio. Results from parametric studies show that axial compressive strength and axial stiffness of square concrete-encased CFST stub columns after fire decrease significantly. The decline of axial stiffness is higher than that of axial compression ultimate bearing capacity. Fire exposure time and sectional core area ratio have significant influence on the reduced level of axial compressive strength and axial stiffness of square concrete-encased CFST stub columns after fire exposure. Steel tube area ratio and reinforcement ratio have some influence on the reduced level. Compressive strength of concrete and yield strength of steel tube have limited influence on the reduced level. [ABSTRACT FROM AUTHOR]

A simple and convenient procedure for the preparation of valuable bis-1,3-dicarbonyl-substituted methane compounds and their derivatives has been developed using inert dichloromethane as one-carbon source in good to excellent yields. [Display omitted] A simple and convenient procedure for the preparation of valuable bis-1,3-dicarbonyl-substituted methane compounds and their derivatives has been developed using inert dichloromethane as one-carbon source in good to excellent yields. The advantages of this protocol are mild reaction conditions, easily scalable and good functional group compatibility. Moreover, the use of cyclic secondary amine as the promoter avoids the presence of transition metal catalysts and oxidants. [ABSTRACT FROM AUTHOR]

The synthesis, structures and properties of five new coordination polymers containing isomeric N , N ′-di(pyridyl)suberoamide and polycarboxylate ligands, {[Cd(1,3-BDC)( L 1 )]·H 2 O} n [ L 1 = N , N ′-di(3-pyridyl)suberoamide; 1,3-H 2 BDC = benzene-1,3-dicarboxylic Acid] 1 ; [Cd(5-OH-IPA)( L 1 )] n (5-OH-IPA = 5-hydroxyisophthalic Acid), 2 ; {[Cd 3 (1,3,5-BTC) 2 ( L 1 ) 3 (H 2 O) 3 ]·8H 2 O} n (1,3,5-H 3 BTC = 1,3,5-benzenetricarboxylic Acid), 3 ; [Cd(5-Br-IPA)( L 2 )] n [ L 2 = N , N′ -di(4-pyridyl)suberoamide; 5-Br-H 2 IPA = 5-bromoisophthalic Acid], 4 ; [Cd(5- tert -IPA)( L 2 ) 0.5 ] n (5- tert -H 2 IPA = 5- tert -butylisophthalic acid), 5 , are reported, which have been characterized by single crystal X-ray diffraction. Complexes 1 and 2 show 2D double layers with the 3,5L2 topology and 3 reveals a 3D structure with the rare 3,4,4T90 topology. Complex 4 is a twofold interpenetrated 2D layer with a 2,6L1 topology and 5 shows a 3D coordination network with a rare 4,6T136 topology. In 5 , the L 2 ligand adopts a unique tetradentate bonding mode through two pyridyl nitrogen and two amide oxygen atoms. The structure-directing role roles of the substituent groups on the polycarboxylate ligands in determining the structural diversity are discussed. Their thermal and luminescent properties are also investigated. [ABSTRACT FROM AUTHOR]

A series of coordination networks constructed from divalent metal ions, N,N ′-di(3-pyridyl)adipoamide ( L ) and phenylenediacetate ligands, including [Co( L ) 0.5 (1,2-pda)(H 2 O)] n (1,2-H 2 pda = 1,2-phenylenediacetic acid), 1 , [Co( L )(1,4-pda)] n (1,4-H 2 pda = 1,4-phenylenediacetic acid), 2 , [Ni 2 ( L ) 2 (1,2-pda) 2 (H 2 O) 2 ·4.5H 2 O] n , 3 , [Ni( L )(1,4-pda)(H 2 O) 0.5 ·2.5H 2 O] n , 4 , [Zn( L ) 0.5 (1,2-pda)] n , 5 , [CdBr( L )(1,2-pda) 0.5 ] n , 6 , and [CdI( L )(1,2-pda) 0.5 ] n , 7 , have been synthesized by hydrothermal reactions and structurally characterized by single crystal X-ray diffraction. Complexes 1 , 2 and 5 adopt the (4 2 ,6 3 ,8)(4 2 ,6)-3,4L83, (4 2 ,6 7 ,8)(4 2 ,6)-3,5L2 and (4 2 ,6 3 ,8)(4 2 ,6)-3,4L83 topologies, respectively, while 3 and 4 show the (4 8 ,6 7 )-6T2 and (4 8 ,6 7 )- sqc26 topologies, respectively, and both 6 and 7 display the (4 12 ,6 3 )- pcu topology. The L ligands in 3 adopt three different conformations, while the pda 2− ligands in 5 adopts the rare cis -conformation and those in the other complexes exhibit the trans -conformation. Moreover, the pda 2− ligands in complexes 1 , 2 and 5 display the μ 3 bonding mode to afford the 2D layer structures, in contrast to those in the other complexes that show the μ 4 and/or μ 2 bonding modes to form the 3D frameworks. The conformations of the L ligands are subject to the changes of metal ions and pda 2− ligands, resulting in various types of structure for 1 – 7 . Temperature-dependent PXRD patterns of complexes 1 , 3 and 4 indicate that their structural transformations upon removal of the water molecules are irreversible. The emission spectra of 6 and 7 reveal that the lower electronegativity of the iodide relative to the bromide has a significant effect on the bathochromic shift. [ABSTRACT FROM AUTHOR]

Abstract: The temperature distribution of concrete filled steel tube reinforced concrete (CFSTRC) square short columns was analyzed. Test results of four CFSTRC square short columns were reported in this paper. The specimens exposed to the ISO-834 standard fire without initial loads. The fire test lasted 180minutes. The influential factors included the side length of cross-section, slenderness ratio and steel tube area ratio. Finite element method (FEM) simulation was used to calculate temperature distribution of CFSTRC square short columns at elevated temperature. The test results show that the larger side length of cross-section, the lower temperature inside the specimens with the same fire exposure time and steel tube area ratio and height of specimens. Under the same fire exposure time and side length of cross- section and steel tube area ratio, the slenderness ratio was larger, and the temperature inside the specimens was lower. With the same fire exposure time and side length of cross-section and slenderness ratio, the steel tube area ratio had slight influence on temperature distribution inside the specimens. The FEM simulation results agreed well with the experimental results. The FEM simulation was capable of calculating temperature distribution of CFSTRC square short columns with an accuracy that was sufficient for design purposes. [Copyright &y& Elsevier]

Abstract: In order to research the calculating method of flexural strength of fire-damaged reinforced concrete (RC) beams with carbon fiber reinforced polymer (CFRP) sheets strengthening, the flexural strength of fire-damaged beam was analyzed with section analysis. The fire exposed region includes tensile region and compressive region. A procedure was developed for quantifying the amount of bending moment of fire-damaged RC beams section with an external strengthening CFRP sheets. An equation of CFRP sheets of effective strain was recommended. The proposed method was verified under the experimental results as well. The results show that the proposed approach is capable of predicting bending moment of fire- damaged RC beams with an accuracy that is sufficient for design purposes. [Copyright &y& Elsevier]

Abstract: For a finite simple edge-colored connected graph (the coloring may not be proper), a rainbow path in is a path without two edges colored the same; is rainbow connected if for any two vertices of , there is a rainbow path connecting them. Rainbow connection number, , of is the minimum number of colors needed to color its edges such that is rainbow connected. Chakraborty et al. (2011)  proved that computing is NP-hard and deciding if is NP-complete. When edges of are colored with fixed number of colors, Kratochvil proposed a question: what is the complexity of deciding whether is rainbow connected? is this an FPT problem? In this paper, we prove that any maximal outerplanar graph is rainbow connected for suitably large and can be given a rainbow coloring in polynomial time. [Copyright &y& Elsevier]

Abstract: A series of 4-hydroxybenzene acrylic acid derivatives were designed and synthesized based on the ferulic acid of natural active ingredients. The tested compound 5a, 5f and 6a have significant anti-inflammatory activity with suppression rates of 45.29%, 44.75% and 24.11%, respectively, compared with that of indomethacin, and their cardiac toxicity was not observed. The structure–function relationship shows that the p-hydroxyl group on the α-position benzene ring, particularly if acetylated, contributes to the considerable anti-inflammatory activity; that the carboxyl group on the double bond, if esterified, also contributes to the anti-inflammatory activity; that the p-methylsulfonyl group on the other benzene ring, whose introduction is due to the COX-2 selectivity, also contributes to anti-inflammatory activity surprisingly. [Copyright &y& Elsevier]

Abstract: A new set of 4-tert-butyldimethylsiloxy-substituted organocatalysts derived from N-prolylsulfonamide has been designed and proved to be effective in catalyzing the direct aldol reactions of cyclic ketones with a series of aromatic aldehydes. Furthermore, to the best of our knowledge, there are no reports on the aldol reaction generating the products in very good yields (>99%) and with excellent diastereoselectivities up to >99:1 and enantioselectivities up to >99% by using lower catalyst loadings (only 3mol%), without using any additives in a large amount of water under mild conditions. [Copyright &y& Elsevier]

Abstract: In graph , a vertex set is called a domination set if any vertex is connected to at least one vertex in . Generally, for any natural number , the -tuple domination set is a vertex set such that any vertex is connected to at least vertices in . The -tuple domination number is the minimum size of -tuple domination sets. It is known that the 1-tuple domination number (i.e. domination number) of classical random graphs with fixed asymptotically almost surely has a two-point concentration [B. Wieland, A.P. Godbole, On the domination number of a random graph, Electron. J. Combin. 8 (2001) R37]. In this work, we prove that the 2-tuple domination number of with fixed . has a two-point concentration. [Copyright &y& Elsevier]

Abstract: A rationally designed 4-phenoxy substituted prolinamide phenols as an efficient hydrophobic organocatalyst for direct asymmetric aldol reaction in water has been developed. High yield (up to 99%), diastereoselectivity (up to 99:1), and enantioselectivity (up to 97%) were obtained under optimal condition. The influence of substituent groups on the reactivity of catalysts was studied in detail. [Copyright &y& Elsevier]

In this study, an electrochemical actuator was prepared by porous nitrogen-doped carbon (NDC) electrode derived from a zeolitic imidazolate framework (ZIF). The microstructure, morphology, and composition of NDC were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM) and X-ray photoelectron spectroscopy (XPS). The NDC exhibited ZIF structures and the specific capacitance of NDC was 224.1 F∙g−1 in KOH aqueous solution (25 mV∙s−1). Furthermore, the electrochemical actuator based on NDC electrode displayed reliable and large bending deformations under low input voltages. The influence of NDC content on electromechanical performance of actuator was investigated. With the increase of NDC content, the actuating displacement of actuator first increased and then decreased, and the 20%NDC electrode based actuator showed the best actuating performance. The tip peak-to-peak displacement and bending strain of the 20%NDC based actuator were 17.5 mm and 0.20% under the applied voltage of ±3 V at a frequency of 0.1 Hz. Therefore, zeolitic imidazolate frameworks can be applied to provide significant improvements in electrochemical actuators, which can play key roles as technological advances toward bioinspired actuating devices for next-generation soft and wearable electronics. Unlabelled Image • Novel electrochemical actuator based on ZIF-structure carbon electrode was reported. • The synergistic effect of ZIF-structure carbon and PEDOT:PSS led to high actuating displacements. • The influence of amount of ZIF-structure carbon on actuating performance was investigated. [ABSTRACT FROM AUTHOR]

A broadband stacked patch antenna array with high port isolation is presented for in-band full-duplex (IBFD) applications in this article. A co-channel feeding scheme is proposed to simultaneously excite two ports of the patch antenna to achieve ± 45°dual polarization. An antenna system is then designed using a 2 × 2 stacked patch array, a parallel feeding network, and a hybrid coupler. The coupling between the Tx and Rx ports due to mismatch and coupling between the antenna elements is analysed in detail and shown to be eliminated completely. A demonstrator is fabricated and measured to endorse the accuracy of the proposed feeding scheme. The measured results show that the developed prototype can operate from 3.15 GHz to 4.0 GHz. The isolation level between Tx and Rx ports is higher than 45 dB within the operating band. The realized gains of two ports are higher than 10.5 dBi throughout the band of interest with the maximum gain of 13.9 dBi, which are congruent with the simulated ones. [ABSTRACT FROM AUTHOR]

Two-dimensional (2D) materials with a high solar to hydrogen (STH) conversion are in high demand due to the escalating energy crisis and environmental degradation. The STH efficiency is strongly correlated with the charge carrier separation, which can be improved by the inside electric dipole. Herein, the water-splitting capabilities of single-layer (SL) GaInS 3 are explored by employing first-principles calculations. Theoretical outcomes reveal that SL GaInS 3 exhibits a large intrinsic electric dipole and has a thermally stable structure at 300 K. SL GaInS 3 displays a direct bandgap of 1.83 eV, as well as suitable band edges and abundant visible absorption (105 cm−1) for solar-driven water-splitting. The electronic structure and carrier mobility calculations demonstrate the high separation efficiency of charge carriers, which is strongly affirmed by the quite long carrier lifetime of 8.26 ns. The overpotential analysis of charge carriers suggests that the oxygen generation of SL GaInS 3 can be accomplished without a cocatalyst, while hydrogen generation can be completed with the aid of cocatalysts. The STH efficiency of SL GaInS 3 reaches up to 16.8%, apparently surpassing the commercial standard (10%). In brief, the high STH and long carrier lifetime promise the possible application of SL GaInS 3 for solar water splitting. What's more, this work provides straight evidence that 2D photocatalysts with inside dipoles exhibit a long carrier lifetime. • Single-layer GaInS 3 has appropriate and edges and abundant visible absorption for solar water-splitting. • The electronic structure confirms the high charge carrier separation efficiency in single-layer GaInS 3. • The quite long carrier lifetime of 8.26 ns in single-layer GaInS 3 is predicted. • The solar to hydrogen conversion of single-layer GaInS 3 reaches up to 16.8%. [ABSTRACT FROM AUTHOR]

Abstract Because of the fluid viscous shear and the asperity contact friction, a temperature rise will occur in the sealing zone, which may cause rupturing of lubrication films or wear failure of seal rings. To investigate the influence of thermal effect on seal behavior, a thermo-elastohydrodynamic (TEHD) lubrication model for hydraulic rod O-ring seals under mixed-lubrication conditions is developed. The operation mechanism of thermal effect on seal behavior is revealed by checking the lubrication film. The TEHD characteristics of an O-ring seal under different operating conditions are analyzed and discussed. The numerical results show that the thermal effect should be taken into consideration in simulation analysis, and the generated heat tends to accumulate on the seal surface in the sealing zone. Highlights • A novel TEHD lubrication model for hydraulic rod O-ring seals under mixed lubrication conditions is developed. • The operation mechanism of thermal effect on seal behavior is revealed by checking the properties of the lubrication film. • Parameterized research results show that the generated heat tends to accumulate on the seal surface in the sealing zone. • The thermal effect would result in the viscosity wedge effect, which is responsible for the changed seal behavior. [ABSTRACT FROM AUTHOR]

By employing the flexible ligands, bis(3,5-dicarboxyphenyl)adipoamide, H 4 L 1 ; bis( N -pyrid-3-ylmethyl)adipoamide, L 2 ; and bis( N -pyrid-3-ylmethyl) suberoamide, L 3 , four coordination polymers of the types {[M( L 1 ) 0.5 ( L 2 )(H 2 O) 2 ]·H 2 O} n (M = Co, 1 ; Ni, 2 ) and {[M 2 ( L 1 )( L 3 ) 2 (H 2 O) 4 ]·3H 2 O} n (M = Co, 3 ; Ni, 4 ) have been hydrothermally synthesized and structurally characterized by single crystal X-ray diffraction. Complexes 1 – 4 are topologically identical coordination polymers having the 2-fold interpenetrating 3D net with the mog topology. Additionally, the Co(II) complexes exhibit the reversible structural transformation with color change on dehydration/rehydration but Ni(II) complexes are unable to show such a behavior. All four complexes display good photo-degradation performance and the Co(II) complexes show slightly higher efficiencies than the Ni(II) ones. [ABSTRACT FROM AUTHOR]