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The built-in electric field (BEF) has been considered as the key kinetic factor for facilitating efficient photoinduced carrier separation and migration of polymeric photocatalysts. Enhancing the BEF of the polymers could enable a directional migration of the photogenerated carriers to accelerate photogenerated charge separation and thus boost photocatalytic performances. However, achieving this approach remains a formidable challenge, which has never been realized in conjugated microporous polymers (CMPs). Herein, we developed a molecular dipole control strategy to modulate the BEF in CMPs by varying the nature of the core. As a result, a series of CMPs with a tunable BEF were designed and prepared via FeCl

Arc stud welding will melt the root of the stud to form a welding collar. For the purpose of exploring the influence of welding collar, numerical method is adopted for the theoretical analysis on shear resistance of the stud under several groups of different welding collar parameters. Firstly, the shear resistance between whether the headed studs considering the welding collars or not is compared. Then, the radius and height parameters of welding collar are changed. Finally, the increment ratio of bearing capacity by welding collars with the same height-diameter ratio is taken into consideration. Experimental data from three push-out test are adopted to validate the accuracy of the numerical method. The results show that the welding collar changes the yield area at the bottom of the stud. The height parameter has less influence than the radius. Under the condition that welding collars have the same height-diameter ratio, the improvement of shear resistance with different diameters roughly converges to 7.28%. The formulas of various countries show that at the height-diameter ratio of 0.25, the average value of bearing capacity of welding collar in various specification approach 7.1% of formula value.

The influence of compaction methods such as the Marshall compaction method (MCM), vibration compaction method (VCM) and gyration compaction method (GCM), on the performance of stone mastic asphalt (SMA-13) mixture has yet to be explored. Therefore, to compare the influences of compaction methods and work on the physical and mechanical properties of SMA-13 mixture, the volume parameters, mechanical properties, and gradation changes of SMA-13 mixture specimens prepared under different vibration compaction times, Marshall double-compaction numbers, and gyration compaction numbers were studied. The compaction method for SMA-13 mixture design was also proposed under the principle of optimum properties. Results demonstrate that the asphalt aggregate ratio and compaction work directly affect the volumetric properties (VV, VFA, and VMA) of asphalt mixture specimens while the raw material and mineral aggregate gradation were fixed. The influence of compaction work on physical properties is greater than that of asphalt aggregate ratio. The mechanical strength of VCM and GCM specimens is higher than that of MCM specimens under the same compaction work and the optimum asphalt aggregate ratio. With the increase in compaction work, the mechanical properties of SMA-13 mixture are improved at the same compaction method and the optimum asphalt aggregate ratio. The aggregate gradation of the SMA-13 mixture before and after compacted using VCM and GCM changes minimally compared with that of the SMA-13 mixture compacted by MCM. Thus, the compaction methods of VCM65 and GCM130 were recommended for SMA-13 mixture design.

The cable hoisting method is the most important construction method for long-span arch bridges. During the hoisting process of the arch rib, the incomplete consolidation of the segment joint due to the temporary connection of the bolts, the deflection of the tower caused by the temporary construction load of the main cable, and the free expansion and contraction of the anchor cable and the buckle caused by the temperature change will all affect the arch rib. The installation line has a greater impact. In this paper, the double-element model calculation method considering the stiffness loss can be used to calculate the correction value of the arch rib installation line more accurately when considering the incomplete consolidation of the arch rib segment joint; the geometric relationship between the cable and the tower is used to deduce the tower The correction calculation formula for the installation alignment of the deflection of the frame and the free expansion and contraction of the anchor cable and the buckle caused by the temperature change is calculated to calculate the correction value of the installation alignment of the arch rib due to the deviation of the tower and the temperature change of the anchor cable and the buckle; A calculation formula for the installation line shape of the arch rib of a largespan cable hoisting arch bridge is proposed, which comprehensively considers various influencing factors. The installation line shape of the arch rib is calculated. Taking the Yunnan Lancang River Bridge as an example, the arch line shape error meets the specification requirements. This article can provide a useful reference for the linear calculation of the arch rib installation of the cable-mounted arch bridge.

The increasing carbon dioxide (CO2) emissions from coal-fired power plants exacerbates the need for polymeric sorbents that can preferentially capture CO2 over nitrogen (N2). Herein we report two amine-functionalized microporous organic polymers (PTPNHs) through one-step facile modification of carboxyl-rich microporous organic polymers (PTPMA) that was prepared from a classic Friedel–Crafts coupling of commercially available monomers. The amidation chemistry enables an unprecedented morphology evolution of the microporous organic polymer from nanospheres to uniform nanorods and the choice of amidation agents allows a good control on the diameter and length of the as-made nanorods. More interestingly, the amine-appended PTPNHs show enhanced CO2 adsorption per unit surface area (0.281 mg/m2, at 273 K/1.0 bar) and exceptionally high ideal selectivity (CO2: N2 = 123) with high affinity towards CO2, despite of their decreased Brunauer–Emmett–Teller (BET) surface areas (554 m2 g−1). The CO2 adsorption per unit surface area of the nanorods is about 1.6 folds of that of pristine PTPMA. This study constitutes a step on regulating channel surface polarity and morphology control, and offers the prospect for low-cost direct CO2 capture technologies.

Developing stable open-pore sorbents with high porosity to efficiently capture radiotoxic iodine from the waste streams of nuclear is highly desirable in addressing the environmental issues. Here, we report three highly stable covalent triazine polymers with the same chemical composition while bearing different degree of crystallinity and pore structures toward iodine capture. The best adsorption capacity of 4.31 g g−1 towards iodine vapor is achieved by CTF-1@ZnCl2 composed of ordered skeletons and uniform 1D open channels. In comparison, the amorphous samples, i.e. CTF-1@ZnCl2·H2O and CTF-1@TFMS, display moderate uptakes of iodine up to 2.41 and 1.18 g g−1, respectively. Similar trend is also demonstrated in the case of iodine retaining in hexane, where the open pore array in the crystalline CTF-1@ZnCl2 contributes significantly to its high adsorption capacity when compared to those interpenetrated and/or low-degree-crosslinked networks. The CTF-1@ZnCl2 after treating by organic solvent/dilute base/acid still maintain the capacities in iodine adsorptions with good recyclability, demonstrating their excellent structural stability. This study illustrates the importance of ordered skeletons and uniform 1D open channels in the adsorption process, which may provide a potential platform targeting for solving key environmental issues.

Two series of flexible ketone-bridged nanoporous organic polymers (NOPs) are readily prepared through one-pot Friedel-Crafts acylation polymerization using pyromellitic dianhydride (PMDA) and terephthaloyl chloride (TC) as acylation reagents, respectively. The carboxyl-appended samples (termed NOP-52@COOH and NOP-53@COOH), derived from PMDA, feature a stable spherical morphology. Unexpectedly, our NOP-52@COOH and NOP-53@COOH deliver much higher surface areas (eg. 738 m2 g−1 for NOP-52@COOH) and pore volumes (eg. 0.53 cm3 g−1 for NOP-52@COOH) than the carboxyl-free samples (i.e. NOP-52 and NOP-53). This is significantly different from the reported trend that the introduction of appended group always leads to inferior surface area and pore volume. The enhancement in porosity originates from the hydrogen-bonding effect between carboxyl and the ketone linkage that effectively prevents the networks from collapsing. More importantly, the as-made carboxyl group-containing networks exhibit stronger affinity towards guest CO2 molecules after comparing to those carboxyl-free ones, and have a competitive CO2 capture capacity under ambient conditions (159 mg g−1, 273 K/1 bar). This provides a feasible pathway for both developing high-surface-area organic polymers with flexible linkages and engineering pore surface properties.

Poly(ionic liquid) membranes (PILMs) can be potentially applied as polyelectrolyte materials in the separation of ampholytes such as amino acids. Therefore, poly(amino acid ionic liquid) membranes (PAAILMs) were prepared by blending poly(amino acid ionic liquids) (PAAILs) and polyvinylidene fluoride (PVDF) in this study. These PAAILMs were characterized by Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), and thermal gravimetric analysis (TGA). Moreover, their mechanical properties, antibacterial and antifouling properties were evaluated. The zeta potential, pore size distribution, porosity, and specific surface area of these membranes were also measured. The membranes were used to separate the amino acid mixture of l-phenylalanine and l-aspartic acid, which are essential for the synthesis of aspartame. The PAAILMs can be used for the selective separation of l-phenylalanine and l-aspartic acid through the Donnan effect. A maximum selectivity of 65% was obtained for the mixed amino acids via one-step separation. These PAAILMs have the advantages of low operating pressure, high water flux, good antibacterial and antifouling properties, and excellent reusability, thereby indicating their potential for industrial application in the separation of l-phenylalanine and l-aspartic acid.

Mesoporous hollow carbon spheres have been considered as promising adsorbents for volatile organic compounds (VOCs) removal. However, the influence of the morphologies and structures on the adsorption performance of VOCs is still unclear. Herein, we developed a novel strategy for the controllable synthesis of nitrogen-doped mesoporous hollow carbon nanomaterials with adjustable morphologies and structures. By simply tuning tetraethyl orthosilicate addition time and ammonia amount in Stober system, bowl-like, hollow, and yolk-shell carbon nanomaterials can be obtained. When used as toluene adsorbents, the bowl-like materials exhibited a capacity of 190 mg/g, higher than other carbon materials with different morphologies. The high adsorption capacity and fast adsorption rate of the bowl-like structures can be attributed to the high surface area, rich microporous/mesoporous structure and unique morphology. Our work provides a new strategy for the designed synthesis of novel VOCs adsorbents with advanced adsorption performance.

Three donor-conjugated units (triphenylamine (TPA)) and phenothiazine (PTZ))-side chain acceptor (cyanoacrylic acid (CAA)) donor-π-acceptor (D-π-A) conjugated polymers with different conjugated units (thiophen and/or 3, 4-ethylenedioxythiophene) were rationally designed and synthesized. The electronic properties and energy levels could be effectively tuned via methodically altering the conjugated units of the resulted polymers (PTPAPTZ, PTPAPTZ-1 and PTPAPTZ-2). Regulating the molecular orbital energy levels can be considered as a direct and effective method to get bathchromic and broad spectra shifts in polymer dyes. Photoelectrochemical cells based on the dye sensitized solar cells (DSSCs) format were fabricated putting the polymers as sensitizers. Device based on PTPAPTZ-2 exhibits a power conversion efficiency of 4.71% with short circuit photocurrent density of 10.8 mA·cm−2, overrating all polymer DSSCs previously disclosed.

Task-specific carbazole-based covalent triazine frameworks (CTF-CSUs) have been designed and prepared. The obtained materials could serve as excellent catalysts for both CO2 chemical fixation and oxygen reduction reaction (ORR). Results shown that using CTF-CSUs as catalysts, the cycloaddition reactions between CO2 and epoxides were readily achieved with extremely high yields (99%) under mild conditions (0.1 MPa, 25 °C). The catalysts could be reused for five times without any obvious loss of catalytic activity. In addition, the as-made carbazole-containing CTFs catalysts delivered attractive ORR activity, superior durability and methanol tolerance relative to commercially available Pt/C reference electrocatalyst (E-TEK). Rich N contents (15.33 wt%) and large surface areas (982 m2 g−1) combining abundant mesopores favor a combination of two-electron and four-electron reduction pathway under alkaline condition. All these attracting characteristics were attributed to their unique structures and strong synergistic effect between carbazole and triazine moieties.

Rich heteroatom-doped conjugated nanoporous polymers with uniform microspherical morphology exhibit remarkably high capacity up to 450 wt% for removing iodine from the vapor phase (at 348 K and atmospheric pressure).

Three kinds of carbazole-based porous organic polymers were successfully prepared via simple Friedel-Crafts alkylation of 1,3,5-tri(9-carbazolyl)-benzene. External cross-linking agents named 1,4-bis(chloromethyl)-benzene, cyanuric chloride, and 1,4-dimethoxybenzene were selected, and the derived polymers (denoted as CSU-CPOPs-1, CSU-CPOPs-2, and CSU-CPOPs-3) gave high surface areas (up to 1032 m2/g) and good stability. Interestingly, varying the nature of "knitting" agents led to an unprecedented morphology evolution, and it is worth noting that a mulberry-like morphology was observed for the case of 1,4-bis(chloromethyl)-benzene. Taking advantage of the unique mulberry-like morphology as well as abundant porosity, CSU-CPOPs-1 showed ultrahigh iodine vapor adsorption performance with a capacity of 494 wt % at 348 K and 1 bar, which is the highest value reported to date for amorphous polymers. This study presented a feasible way to develop efficient iodine sorbents with tunable morphologies for addressing environmental issues.

Synthesis of adsorbents with permanent micro/mesoporous structures, tunable functional groups and processability is of great interest in industrial-scale processes for treating dye wastewater. Herein, a feasible crosslinking method has been employed to prepare porous ionic polymers (imidazolium and pyridinium-based) as adsorbents. The obtained materials have been utilized for the removal of methyl orange from aqueous solution and the maximum capacities of imidazolium-based adsorbents reached up to 1159 mg/g, which is superior to those of pyridinium-based ones and most known porous sorbents. The binding energies drawn from theoretical calculations based on density functional theory (DFT) proven the strong interactions between ionic units and dyes. Furthermore, freestanding porous membranes were fabricated from the adsorbents successfully by a step-by-step cross-linking process, implying their great potential in practical anionic dye removal.

With the emergence of asymmetric long-span suspension bridge, it is necessary to study the optimization of hoisting sequence of the main girder of this type of suspension bridge. According to the relationship between the lifting sequence of the main girder and the pushing scheme of the pylon, the method flow of optimizing the lifting sequence of the main girder of the asymmetric long-span suspension bridge is given. Taking an asymmetrical long-span suspension bridge in Guangdong Province as an example, this method is used to optimize the hoisting sequence of the main girder and put it into practice. Good results are obtained and verified: the hoisting of the main girder should be carried out from the middle of the span to the two pylons, and the hoisting speed of the middle side span should be consistent with the proportion of the standard beam sections of the middle side span, and the maximum allowable deviation of the pylon and the main girder should be used in the jacking scheme of the pylon The hoisting sequence shall be formulated based on. It can provide a useful reference for the hoisting of the main girder of the same type suspension bridge and the suspension bridge with slings on both sides of the bridge.

Mesoporous carbons are widely utilized as adsorbents for adsorptive removal of nitrogen-containing compounds in fuel. Herein, hollow mesoporous carbon nanospheres (HMCNs) were successfully synthesized via a facile silica-assisted sol-gel strategy and further oxidized by different acids (HNO3, H2SO4, and (NH4)2S2O8) to adjust their surface chemistry. The HMCNs oxidized with (NH4)2S2O8 contain the most oxygen-containing groups and exhibit the strongest acidity, resulting in high adsorption capacities towards quinoline (QUI, 29.78 mgN·g−1) and indole (IND, 26.59 mgN·g−1) in model fuel. The superior performance is attributed to the acid-base interaction and hydrogen bonding interaction between the adsorbent and QUI/IND molecules. Remarkably, the adsorption capacity towards nitrogen-containing compounds in real diesel is as high as 19.19 mgN·g−1 at 50 oC. Our work has paved the way to the rational design and synthesis of high-performance adsorbents for the removal of nitrogen-containing compounds in real diesel on a large scale.

Polymeric membranes with high permeability for oxygen separation are highly demanded for a variety of industrial sectors. We herein developed a novel multi-component membrane system with improved O2/N2 separation performance, through physical blending an azo-bridged porous organic polymers (AZOPOP) with commercially available poly(phthalazinone ether sulfone ketone) (PPESK). The AZOPOP, featuring an acceptable BET surface area and a dominant pore size centered at 0.95 nm and 27 nm, was facilely synthesized through Mills polycondensation between 2,6-dinitrosotriptycene and 2-(4-aniline)-4-(4-phenylamine) (2H) naphthyridin-1-one containing phthalazinone. The composite membrane AZOPOP/PPESK37 showed an excellent O2 permeability (e.g., PO2 = 1944 barrer) and ideal selectivity (PO2/PN2 = 2.6) for O2/N2 pair, which surpassed the 1991 Robeson upper bound and approached to the 2008 Robeson upper bound. Its higher flux over neat PPESK was attributed to abundant pores and good compatibility between the matrix resin and filler, while the decent selectivity for O2/N2 was induced by nitrogen-phobic functional groups incorporated. This work provides an alternative strategy to fabricate polymeric membranes that have great potentials for O2/N2 separations by taking advantages from the porous structures contributed by rigid chain conformations of AZOPOP.

Membrane technology has evolved as an alternative candidate for CO2 separation due to their inherent attributes, such as high energy efficiency, small capital investment, and environmentally benign characteristics. The key point of developing advanced membranes with satisfied performance is to find the balance between selectivity and permeability. Recently, advanced porous open framework materials, especially covalent organic frameworks (COFs), have attracted much attentions in academia and industry due to their high porosity, large surface area and regular pore size. Moreover, their adjustable pore size, diversify topological structure and sieving capacity further endowed them with unprecedented opportunities for efficient CO2 separation. This mini-review concluded and discussed the fabrication strategies as well as CO2 separation properties of COFs-based membranes in the past five years (from 2014 to present). The opportunities and challenges in the related fields are also summarized.

The development of new photocatalytic platforms using novel semiconductor material is an important challenge. Herein, a sp2 carbon-conjugated covalent triazine polymer (sp2 c-CTP-4), featuring a vinylene bridge and extended π-conjugation, is prepared as a highly efficient photocatalyst for degradation of methylene blue. sp2 c-CTP-4 exhibits substantial semiconducting properties such as enhanced charge transfer and prolonged lifetime of carriers compared to its counterparts with CN or CC connections, likely due to its extended π-delocalization with an unencumbered CC bridge. Moreover, benefiting from its high chemical stability, the as-made catalyst can be recycled five times with good retention of photocatalytic activity. This study provides a new pathway for constructing a robust platform for efficient photocatalysis and gives insight into the structure-property relationship of conjugated polymers.

A damage constitutive model with 3 independent parameters is derived from the two-order form of the general theory for elastic damage problems. Based on this damage constitutive model and by using damage mechanics – additional load – finite element method, a three dimensional finite element analysis computer program is established. The damaging process and failure of a reinforced concrete arch structure which was removed from a real old bridge is simulated numerically. The damage parameters of concrete are determined through a targeting calculation process. The values of element damage and the nodal displacements along three directions under different load level are obtained. The theoretical results of the failure mode, displacements are in good agreement with the experimental observations. Numerical results reveal the complicated behavior of concrete in a damaging process. The reinforced concrete structures exhibit pronounced nonlinearity at large loading levels.

Tetrakis(1-adamantanecarboxymethyl)methane was prepared by indirect esterification. DSC traces of tetrakis(1-adamantanecarboxymethyl)methane showed two endothermic peaks. Entropy ratio of these two...

New classes of nanoporous organic polymers based on 1,3,5-triazine units (NOP-1–6) were synthesized via a straightforward, methane-sulfonic acid-catalysed, cost-effective Friedel–Crafts reaction of 2,4,6-trichloro-1,3,5-triazine and tetrahedral building blocks. Among them, NOP-3 with a Brunauer–Emmet–Teller (BET) specific surface area up to 894 m2 g−1 and the total volume exceeding 0.41 m3 g−1 exhibits good hydrogen adsorption capacity (up to 1.14 wt% at 77 K/1.0 bar) and high carbon dioxide uptake (up to 11.03 wt% at 273 K/1.0 bar). Furthermore, it presents an effective selectivity for CO2 adsorption (NOP-6, CO2/N2 selectivity 38.7 at 273 K/1.0 bar), demonstrating potential applications in gas adsorption and separation.