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Chemical doping is verified to be a promising strategy to regulate local electron distribution and further promote the poor intrinsic catalytic activity of graphdiyne. However, the current doping approach still faces problems such as precise doping for creating active sites and the destruction of graphdiyne skeleton calling for high temperature. Here, we achieved charge redistribution on graphdiyne surface through molecule functionalization. A p-type molecule–F4TCNQ (2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane) was introduced and the site-defined functionalization was accomplished. Theoretical calculations showed that the charge transfer ability is improved and graphdiyne becomes positively charged. The oxygen reduction electrocatalysis was conducted as a proof of principle, where the electronic states of sp hybridized C active site was tuned toward favorable reaction intermediates’ adsorption. Such work from both theoretical prediction and experimental validation, found that molecule functionalization is effective to promote the electrocatalytic oxygen reduction, which creates new possibilities for graphdiyne’s applications in different electrochemical reactions.

Due to the limited reserves of metals, scientists are devoted to exploring high-performance metal-free catalysts based on carbon materials to solve environment-related issues. Doping would build up inhomogeneous charge distribution on surface, which is an efficient approach for boosting the catalytic performance. However, doping sites are difficult to control in traditional carbon materials, thus hindering their development. Taking the advantage of unique sp-C in graphdiyne (GDY), a new N doping configuration of sp-hybridized nitrogen (sp-N), bringing a Pt-comparable catalytic activity in oxygen reduction reaction is site-defined introduced. However, the reaction intermediate of this process is never captured, hindering the understanding of the mechanism and the precise synthesis of metal-free catalysts. After the four-year study, the fabrication of intermediate-like molecule is realized, and finally sp-N doped GDY via the pericyclic reaction is obtained. Compared with GDY doped with other N configurations, the designed sp-N GDY shows much higher catalytic activity in electroreduction of CO

The liver plays an essential role in multiple biological functions including metabolism, detoxification, digestion, coagulation, and homeostasis in vertebrates. The specification and differentiation of embryonic hepatoblasts, the proliferation of hepatocytes, and the hepatic tissue architecture are well documented, but molecular events governing the maturation of hepatocytes during liver development remain largely unclear. In this study, we performed a comparative transcriptome analysis of hepatocytes that were sorted by flow cytometry from developing zebrafish embryos at 60, 72, and 96 hpf. We identified 667 up-regulated and 3640 down-regulated genes in hepatocytes between 60 and 72 hpf, 606 up-regulated and 3924 down-regulated genes between 60 and 96 hpf, and 1693 up-regulated genes and 1508 down-regulated genes between 72 and 96 hpf. GO enrichment analysis revealed that key biological processes, cellular components, and molecular functions in hepatocytes between 60 to 72 hpf, such as cell cycle, DNA replication, DNA repair, RNA processing, and transcription regulation, are mainly associated with the proliferation of hepatocytes. In addition to biological processes, cellular components, and molecular functions for cell proliferation, molecular functions for carbohydrate metabolism were enriched in hepatocytes during 72 to 96 hpf. KEGG enrichment analysis identified key signaling pathways, such as cell cycle, RNA degradation, ubiquitin-mediated proteolysis, ErbB and Hedgehog signaling, basal transcription factors, Wnt signaling, and glycan degradation, which are closely associated with cell proliferation or carbohydrate metabolism in hepatocytes between 60 to 72 hpf. Newly enriched signaling pathways in hepatocytes during 72 to 96 hpf include metabolisms of pyrimidine, purine, nicotinate and nicotinamide, caffeine, glycine, serine and threonine, ABC transporters, and p53 signaling that function in metabolisms of lipid, protein and energy, cellular secretion, or detoxification, indicating the functional maturation of hepatocytes between 72 to 96 hpf. These findings provide novel clues for further understanding the functional differentiation and maturation of hepatocytes during liver development.

The recently discovered carbon allotrope GDY possesses rich acetylenic bonds and unique pore structures, prompting GDY as an ideal candidate, tuning its electronic structure by introducing heteroatoms, broadening its usage in catalysis, energy storage and other fields. In this paper, we review different approaches to introduce heteroatoms into GDYs, including monodoping and co-doping, predesigned bottom-up synthesis of GDY, the anchoring of metal atoms into GDYs. Furthermore, we introduce the electronic properties' modification caused by these heteroatoms, including reduced diffusion barrier and adsorption energy, abundant active sites, high reversible capacity and cyclic stability, better rate performance and longer lifespan. Furthermore, the topological molecular structure of GDYs can be tuned through bottom-up synthesis methods with different monomers. GDY has great prospects for inclusion in energy storage devices such as sodium-ion batteries, lithium-ion batteries, lithium/magnesium sulfur batteries, and in electrocatalytic processes such as hydrogen evolution reactions, oxygen reduction reactions, and electrocatalytic nitrogen reduction reactions in important industrial reactions. At the end of this review, challenges and prospects of heteroatoms' introduction into GDY are discussed.

Zn–air batteries have drawn extensive attention owing to their high specific energy, light weight, convenient operation, and environmental friendliness. However, their practical application remains a challenge due to unsatisfactory performance and high-cost. Engineering highly efficient electrocatalysts, especially metal-free ones, for Zn–air batteries is crucially important. Doping heteroatoms can provide more active sites by the modification of electron distribution, and thus the rational design of the doping form and amount is an effective approach for performance enhancement. Herein, the unique sp-hybridized nitrogen atoms (sp-N) are site-specifically doped into graphdiyne (GDY) at a higher amount and with good selectivity. The precisely constructed sp-N doped GDY displays superior electrocatalytic activity and durability, which make it a distinctive air cathode for Zn–air batteries. Importantly, as an air cathode, sp-N doped GDY displays outstanding performance and robust stability, affording a peak power density of 195.7 mW cm−2, exceeding that of the commercial Pt/C catalyst (180.3 mW cm−2), and prominent stability. This work provides an extraordinary route for advancing metal–air cathode materials.

SMC2 (structural maintenance of chromosomes 2) is the core subunit of condensins, which play a central role in chromosome organization and segregation. However, the functions of SMC2 in embryonic development remain poorly understood, due to the embryonic lethality of homozygous SMC2−/− mice. Herein, we explored the roles of SMC2 in the liver development of zebrafish. The depletion of SMC2, with the CRISPR/Cas9-dependent gene knockout approach, led to a small liver phenotype. The specification of hepatoblasts was unaffected. Mechanistically, extensive apoptosis occurred in the liver of SMC2 mutants, which was mainly associated with the activation of the p53-dependent apoptotic pathway. Moreover, an aberrant activation of a series of apoptotic pathways in SMC2 mutants was involved in the defective chromosome segregation and subsequent DNA damage. Therefore, our findings demonstrate that SMC2 is necessary for zebrafish liver development.

SMC2 (structural maintenance of chromosomes 2) is the core subunit of condensins, which play a central role in chromosome organization and segregation. However, the functions of SMC2 in embryonic development remain poorly understood, due to the embryonic lethality of homozygous SMC2−/− mice. Herein, we explored the roles of SMC2 in the liver development of zebrafish. The depletion of SMC2, with the CRISPR/Cas9-dependent gene knockout approach, led to a small liver phenotype. The specification of hepatoblasts was unaffected. Mechanistically, extensive apoptosis occurred in the liver of SMC2 mutants, which was mainly associated with the activation of the p53-dependent apoptotic pathway. Moreover, an aberrant activation of a series of apoptotic pathways in SMC2 mutants was involved in the defective chromosome segregation and subsequent DNA damage. Therefore, our findings demonstrate that SMC2 is necessary for zebrafish liver development.

Concrete structures in salt lakes of western China and South China Sea deteriorate dramatically because of the aggressive salt, high temperature and low relative humidity (RH). In order to study the deterioration mechanism of cement-based materials in these severe environments, the damage progress of mortar specimens that partially exposed to sulfate solutions and under different ambient RH and temperatures was examined. The results indicate that the driving deterioration mechanism for cement mortars that partially exposed to Na2SO4 solution is physical attacks in drying portions, while it is chemical attacks in immersed portions for cement mortars that partially exposed to MgSO4 solution. Besides, lowering the ambient RH (e.g., from 80% to 50% and 30%) would promote a narrow but supersaturated evaporation interface zone, which accelerates the salt crystallization and eventually surface scaling. While the relatively high ambient RH (80%) causes a broad diffusion zone where the chemical related expansion and cracking formed. Moreover, an intermediate temperature of 35 °C is proved to produce the most severely deterioration when compared to the temperature of 20 and 50 °C.

Recycled clay brick powder (CBP) from waste clay bricks was utilized as a supplementary cementitious material to partially replace cement to prepare cement pastes or mortars. The compressive strength, hydration products and microstructure of these blended samples under different curing time were investigated to explore the pozzolanic reaction of CBP. The results showed that the compressive strength of mortars contained CBP decreased gradually with the replacement level of CBP increasing at early age. However, the compressive strength of blended mortars developed gradually at later curing time and the mortar contained 20% achieved the highest compressive strength of 62.2 MPa at 90 days. The XRD results demonstrated that the addition of CBP resulted in the formation of C-A-H gel in blended pastes after 28 days. SEM pictures also found that the microstructure of blended pastes became more compact with curing time increasing, and SEM-EDS demonstrated that C-A-S-H gel was produced in blended pastes. Finally, it could be concluded that C-A-H and C-A-S-H gel were produced due to the pozzolanic reaction of CBP and the microstructure of specimens with CBP became more compact, which lead to compressive strength of blended specimens increasing gradually.

Developing metal-free catalysts with high catalytic activity for oxygen evolution reaction (OER) is essentially important for energy and environment-related techniques. Compared with individual element doping, doping carbon materials with multiple heteroelements has more advantages for enhancing the OER performance. However, doped sites for the different atoms are highly uncontrollable under the reported methods, which hinder the deeper understanding on the relationship between structure and property, and also limit the enhancement of catalytic activity. Our latest research has reported a method to site-controlled introducing a new form of nitrogen atoms, i.e. sp-hybridized nitrogen (sp-N), into graphdiyne, showing its potential advantages in OER catalysis. Since the sites of sp-N atoms are defined in graphdiyne, and the doping sites for S atoms are well understood, the relative position between N and S can be further defined. It gives us a chance to understand deeply the mechanism in the N, S heteroelements doped metal-free catalyst. Experimental results present that the codoping of sp-N and S atoms brought an excellent OER performance with low overpotential and high current density owning to the effectively synergistic effect of the stereodefined heteroatoms. This work was supported by the National Key Research and Development Program of China (2016YFB0600903) and the National Natural Science Foundation of China (21590795, 21820102002), the Scientific Instrument Developing Project of the Chinese Academy of Sciences (Grant No. YZ201623), Queensland-Chinese Academy of Sciences Collaborative Science Fund (122111KYSB20170001), and Chinese Academy of Sciences (CAS) Interdisciplinary Innovation Team.

The dehydration products of gypsum under different temperature and water vapor pressure were investigated by thermodynamic theory. Additionally, the rehydration mechanism of soluble anhydrite was also studied by Monte Carlo (MC) simulations. The thermodynamic calculation results reveal that the dehydration mechanism of gypsum significantly depended on ambient temperature and water vapor pressure. In the high-temperature and low water vapor pressure region, gypsum dehydrates to form γ-CaSO4 in a single-step process (CaSO4·2H2O → γ-CaSO4); with increasing water vapor pressure, gypsum undergoes the CaSO4·2H2O → γ-CaSO4 → β-CaSO4·0.5H2O reaction path and as water vapor pressure increases further, the occurrence of a two-step conversion path CaSO4·2H2O → β-CaSO4·0.5H2O → γ-CaSO4 was observed. It was also found that gypsum is stable in the low-temperature and high water vapor pressure region and does not dehydrate to form any calcium sulfate hemihydrate. Finally, the rehydration mechanism of soluble anhydrite was studied by MC simulations. The simulation results are in agreement with the experimental data and support the finding that γ-CaSO4 rehydration forms CaSO4·0.67H2O in high relative humidity. Another important result revealed by the MC simulation is that γ-CaSO4 has an extraordinary ability to capture water molecules from an extremely dry atmosphere, which is very useful in some fields, such as in drying processes and even for extracting liquid water from extremely dry atmosphere.

Structure and facet control are considered to be effective routes to enhance catalytic performance. We successfully synthesized hollow multi-shelled structures (HoMSs) of a Co3O4 dodecahedron by adopting metal–organic frameworks (MOFs) as templates and using the sequential templating approach (STA). Importantly, owing to the topological arrangement of metal atoms in MOFs, the Co3O4 nanocrystals in HoMSs are assembled in the desired orientation, forming a unique shell with dominant exposure of (111) facets. This process is defined as “genetic inheritance” in this work. In addition, these exposed facets possess high activity for photocatalytic CO2 reduction. Adding this to the properties inherited from HoMSs, i.e., multiple interfaces and strong solar light harvesting, these Co3O4 HoMSs present high catalytic activity for CO2 photoreduction. The catalytic activity of quadruple-shelled (QS) Co3O4 HoMSs was about 5 and 3 times higher than that of Co3O4 nanoparticles and Co3O4 HoMSs without facet control, resp...

Most currently available bioreactors have some defects in the expression, activity, or purification of target protein and peptide molecules, whereas the mucus gland of fish can overcome these defects to become a novel bioreactor for the biopharmaceutical industry. In this study, we have evaluated the practicability of developing a mucus gland bioreactor in loach (Paramisgurnus dabryanus). A transgenic construct pT2-krt8-IFN1 was obtained by subcloning the promoter of zebrafish keratin 8 gene and the type I interferon (IFN1) cDNA of grass carp into the SB transposon. The IFN1 expressed in CIK cells exhibited an antiviral activity against the replication of GCRV873 and activated two genes downstream of JAK-STAT signaling pathway. A transgenic loach line was then generated by microinjection of the pT2-krt8-IFN1 plasmids and in vitro synthesized capped SB11 mRNA. Southern blots indicated that a single copy of IFN1 gene was stably integrated into the genome of transgenic loach. The expression of grass carp IFN1 in transgenic loaches was detected with RT-PCR and Western blots. About 0.0825 &micro, g of grass carp IFN1 was detected in 20 &micro, L mucus from transgenic loaches. At a viral titer of 1 &times, 103 PFU/mL, plaque numbers on plates containing mucus from transgenic loaches reduced by 18% in comparison with those of the control, indicating that mucus of IFN1-transgenic loaches exhibited an antiviral activity. Thus, we have successfully created a mucus gland bioreactor that has great potential for the production of various proteins and peptides.

Early hydration and microstructure of gypsum plaster (G) paste in different compositions and hydration time were studied by environment scanning electron microscope (ESEM) coupled with liquid nitrogen cooling. It was observed that small hemihydrate particles rapidly dissolved and hydrated, forming dihydrate crystals network around large hemihydrate particles, which makes an increasingly dense microstructure and promotes the setting of G paste. Besides, different chemical admixtures such as polycarboxylate (PC), hydroxy propyl methyl cellulose (HPMC) and starch ether (SE) would promote the flocculating or deflocculating between particles and therefore modify the fluidity of the paste. This work paves the way to the understanding the setting and rheology of hydraulic materials in the perspective of microstructure evolution.

The amount of waste clay bricks has been increasing as the demolition of old buildings in China, which has caused the serious environmental problem. Utilizing waste clay bricks as lightweight aggregates for preparing concrete is a new idea to consume them and save natural resources. Based on this concept, an experimental study was carried out to evaluate the feasibility of preparing lightweight aggregate concrete with waste clay bricks by testing the properties of prepared lightweight aggregate concrete. The results indicate that the dry densities of all mixtures are about 1700 kg/m3∼1850 kg/m3, meeting the standard requirement for lightweight aggregate concrete (≤1950 kg/m3), the 28-day compressive strength could reach up to 40 MPa, and corresponding static elasticity modulus is about 26 GPa. Moreover, both freeze-thaw resistance and carbonation resistance of all mixtures could satisfy the service requirements of Chinese standard (JGJ 51), and the chloride migration coefficient varies from 5.0 × 10−12 m2/s and 19.0 × 10−12 m2/s, corresponding with chloride penetration resistance of concrete from high to low. It has been proved that consuming waste clay bricks by preparing lightweight aggregate concrete with waste clay bricks as coarse and fine aggregates is a promising way and has application potentials.

Phosphogypsum (PG) which is a waste byproduct of fertilizer production is the promising source of the gypsum industry. In order to explore the application of hemihydrate PG (HPG) as a substitute of hemihydrate gypsum, the setting and hardening characters of HPG plaster at different pH after neutralization were examined and contrasted with hemihydrate flue gas desulfurization gypsum (HFGD) plaster. Results showed that HPG plaster sets slow with a fall in strength and this effect was more pronounced after retarders were added when pH increased from 5.85 to 11.08. By contrast, HFGD plaster sets fast and without strength variation in the similar alkaline range. Microscopic studies including chemically combined water and temperature evolution curves of HPG plaster revealed that with the increase of the pH, the hydration reaction mechanism of hemihydrate and the gypsum crystal morphology were radically changed due to the fact of interaction between impurities and alkali. Consequently, HPG plaster is very different from HFGD plaster and its application in the alkaline condition was restricted.

The oxygen reduction reaction (ORR) is a fundamental reaction for energy storage and conversion. It has mainly relied on platinum-based electrocatalysts, but the chemical doping of carbon-based materials has proven to be a promising strategy for preparing metal-free alternatives. Nitrogen doping in particular provides a diverse range of nitrogen forms. Here, we introduce a new form of nitrogen doping moieties —sp-hybridized nitrogen (sp-N) atoms into chemically defined sites of ultrathin graphdiyne, through pericyclic replacement of the acetylene groups. The as-prepared sp-N-doped graphdiyne catalyst exhibits overall good ORR performance, in particular with regards to peak potential, half-wave potential and current density. Under alkaline conditions it was comparable to commercial Pt/C, and showed more rapid kinetics. And although its performances are a bit lower than those of Pt/C in acidic media they surpass those of other metal-free materials. Taken together, experimental data and density functional theory calculations suggest that the high catalytic activity originates from the sp-N dopant, which facilitates O2 adsorption and electron transfer on the surface of the catalyst. This incorporation of chemically defined sp-N atoms provides a new synthetic route to high-performance carbon-based and other metal-free catalysts.

As a new member of the carbon allotrope family, graphdiynes (GDs) consist of both sp- and sp(2)-hybridized carbon atoms, possessing unique pi-conjugated carbon skeletons and expanded 18C-hexagonal pores in two dimensions. In contrast with the zero band gap graphene (GR), GD is a semiconductor with a direct band gap of 1.22 eV calculated according to the density functional theory (DFT) using the HSE06 method; this makes it a potential semiconductor material that can supplant silicon in the integrated circuit industry. Moreover, owing to the presence of diacetylenic linkages between its hexagonal carbon rings, GD shows electron-deficient properties, which lead to its electron-accepting tendency. Graphdiynes exhibit unusual semiconducting properties with excellent charge mobilities and electron transport properties that are associated with its distinct topological and electronic structures. Graphdiynes play the role of not only electron-acceptors that efficiently collect the electrons from other materials but also electron-donors that inject electrons into other systems, thus exhibiting excellent electron-transfer enhancement characteristics. The unique electron-transfer enhancement property of GDs inspired us to summarize the interactions between GDs and other materials including metal oxides, metal nano-particles, and organic molecules. In this review paper, we first introduce the TiO2/GD nanocomposite, because the linking of GDs and titania nanoparticles (P25) through the Ti-O-C bond sets an important precedent for exploring the electron-transfer behaviors involving GDs and the metal oxide. These results indicate that the GDs can act as acceptors of the photogenerated electrons in the TiO2/GD system, effectively suppressing charge recombination and resulting in excellent photocatalytic properties. Nevertheless, the GDs in CdSe quantum dots (QDs)/GD composites are able to collect photogenerated holes from the QDs and perform as promising hole-transfer materials in the photoelectrochemical cell for water splitting. As a result, the interactions between GDs and various metal compounds should be explored to deeply understand the electron-transfer properties of GDs. Furthermore, GDs can be also used as electron donors to reduce PdCl42- to Pd nanoparticles that can subsequently be used for the electroless deposition of highly dispersed Pd nanoparticles. Based on electrostatic potential surface analysis over the Pt-2/GD, GDs can attract the electron cloud from the Pt nanoparticles and produce a positive polarization of the metal atom surface. However, due to its large pi-conjugated system, GD can also collect and transfer electrons from the electrode under a bias voltage, making it a new type of electrocatalyst material, especially for single-atom catalysts. The interactions between GDs and metal particles/clusters/atoms have attracted the broad attention of the rapidly developing field of single-atom catalysis. Finally, research on the interactions between GDs and organic molecules, especially biomolecules, is still in its infancy and requires development. In summary, we overview the recent research progress on GD and its enhanced ability for electron transfer in this review paper, including metal oxides/GD, metal nano-particles/GD, polymers/GD, and organic molecules/GD, from both experimental and theoretical perspectives, and emphasize the interactions and electron-transfer enhancement properties.

The slag from industrial byproduct and clay brick powder (CBP) from construction waste were used to replace 30% Portland cement for preparing blended cement. This research investigated the hydration heat, hydration products, microstructure and macro-mechanical properties of blended cement to reveal the combined effect of slag and CBP on hydration. The test results indicate that 30% slag and CBP can increase 11.4 ~ 13.7% peak value of C3S hydration, but the C3A hydration is more affected by slag than CBP. Meanwhile, the 144-h cumulative heat of blended cement hydration is reduced by 4.1 ~ 21.3% compared to Portland cement. The slag and CBP have an improvement effect on the mechanical strength of mortars before and after 90 d, respectively. The mechanical strength of mortars containing both slag and CBP can develop continuously for a long time and reaches the highest value of 53.5 MPa. The slag can consume more portlandite than CBP before 90 d, the portlandite contents in C7B0 and C7B100 at 90 d are 11.6% and 13.3%, respectively. But after 90 d, the CBP will react with more portlandite for its pozzolanic activity. Some different morphologies of CASH can be observed in blended cement paste due to the variation of Al/Si and Ca + Mg/Al + Si in CASH. It could be concluded the combined effect of slag and CBP will led to a high hydration degree at an early stage and continuous hydration for a long time in blended cement.

Zebrafish has become an excellent model for studying the development and function of inner ear. We report here a zebrafish line in which claudin 7b (cldn7b) locus is interrupted by a Tol2 transposon at its first intron. The homozygous mutants have enlarged otocysts, smaller or no otoliths, slowly formed semicircular canals, and insensitiveness to sound stimulation. These abnormal phenotypes and hearing loss of inner ear could be mostly rescued by injection of cldn7b-mRNA into one-cell stage homozygous mutant embryos. Mechanistically, cldn7b-deficiency interrupted the formation of apical junction complexes (AJCs) in otic epithelial cells of inner ear and the ion-homeostasis of endolymph, which then led to the loss of proper contact between otoliths and normally developed hair cells in utricle and saccule or aberrant mechanosensory transduction. Thus, Cldn7b is essential for the formation and proper function of inner ear through its unique role in keeping an initial integrity of otic epithelia during zebrafish embryogenesis.

Structure and facet control are considered to be effective routes to enhance catalytic performance. We successfully synthesized hollow multi-shelled structures (HoMSs) of a Co

Hydrogen evolution reaction (HER) catalysts based on noble metals traditionally suffered from high cost, low activity, and poor stability. Metal-free catalysts originating from heteroatom-doped carbon materials have been proposed to address these problems, in which the doping configurations and electronic structures are critical for modulating the electrocatalytic activity. Herein, we reported a sequential approach for the co-doping of B and N atoms into graphdiyne (GDY). We noticed that the configurations of heteroatoms are strongly related to the doping process, and the subsequent HER test shows that a certain sp-N can decrease the overpotential, and further introduction of B atoms can continuously enhance the current density owing to the synergistic effect of chemical and electronic couplings on proton adsorption/reduction kinetics. This work provides a deeper understanding of developing dual heteroatom doped non-metallic catalysts.

This study focuses on the blended cement containing ground granulated blast furnace slag (GGBFS) and waste clay brick (CBP), with 30% and 50% Portland cement contents. The compressive strength, hydration kinetics, hydration products and microstructure of blended cement up to 365 d were investigated to explore GGBFS and CBP interaction in the blended cement. The results show that both GGBFS and CBP reduce the hydration heat of blended cement, but the GGBFS will accelerate the C3A hydration more significantly due to consuming more sulfate than CBP. The improvement effect of GGBFS on compressive strength mainly occurs before 90 d, while the reaction of CBP continues to improve the compressive strength after its drastic reduction at early age. The X-ray diffraction and thermogravimetry results prove that the blended cement containing both GGBFS and CBP shows a high hydration degree at early age and will continue to hydrate. Furthermore, the chemically bound water content and porosity in blended cement containing both GGBFS and CBP at 365 d are almost the same as those in Portland cement.

This paper aims to systematically investigate the impacts of hybrid fibers on properties of high strength fiber-reinforced self-consolidating concrete (FRSCC). In total, nine mixtures with different fiber types (Polyvinyl Alcohol/PVA, and hybrid fibers) and fiber factors (λ = 0 ~ 70) were fabricated with same basic mix proportioning. Workability tests include slump flow, T50 time, and J-ring tests were carried out to quantify the effects of fiber factor. The compressive strength, four-point bending tests, drying shrinkage, and compressive creep tests were performed on hardened concrete to reveal the intrinsic effects of single/hybrid fibers. Finally, a hyperbolic drying shrinkage prediction model with fiber factor was proposed. Experiment results indicated that single PVA fibers displayed identical influences on slump flow as steel fiber with similar fiber factor, however, can result in higher viscosity. Meanwhile, PVA fibers reduced the compressive strength and displayed limited restraining effects on the specific creep. However, the positive synergetic effects of hybrid fibers can reverse the reductions in compressive strength caused by the PVA fiber and increase flexural performances with multi-scale bridge effects. Moreover, hybrid fibers are more effective in inhibiting the time-dependent strains of FRSCC, followed by steel fiber and synthetic PVA fiber. The proposed hyperbolic drying shrinkage model is capable of predicting the drying shrinkage of FRSCC with a suitable shrinkage halftime.

In this study, the effect of two polysaccharides including hydroxypropyl starch (HPS) and hydroxypropyl methyl cellulose (HPMC) on setting and rheological behavior of gypsum-based materials (GM) pastes were investigated through a series of setting and rheological property tests and microstructure characterization. The results show that HPS is mainly adsorbed on hemihydrate gypsum particles and can promote flocculation or deflocculation structures in different dosages range, as a consequence behaving as a thickener and setting accelerator below the critical dosage of 0.02 wt%, while acting as a retarder beyond this dosage. Besides, the excess HPS would be also selectively adsorbed on dihydrate gypsum crystals and result in the oriented growth. By comparison, HPMC tends to disperse in interstitial solutions and can wrap plenty of free water inside their structures, viscosifying interstitial solutions and strengthening flocculation structures simultaneously. Therefore HPMC has thickening and setting accelerating effects in all dosages range.

Different from other carbon allotropes, graphdiyne (GDY) features topological sp- and sp2-hybridized carbon atoms. With the unique structural advances, a charming electronic behavior has been presented by GDY, which has shown great improvement for various energy-related fields. Inspired by this, it is time to summarize the structure-induced property enhancement. Firstly, different stacking configurations in GDY can induce specific electronic properties, bringing promising energy application. Secondly, uniform pores provide enough sites for anchoring atoms and nanoparticles, enriching the diversity of materials. Thirdly, the sufficient alkynyl groups offer active sites for doping and grafting, providing possibilities for the precise design at the molecular level. Lastly, we propose some perspectives for future trends on GDY. Through this review, we hope to provide a guideline for rational design on GDY-based materials and reveal the structure-performance relationship between functionalized GDY and energy conversion/storage.

The creep behavior of polyvinyl alcohol (PVA) fiber reinforced engineered cementitious composite (PVA-ECC) was experimentally investigated through long-term uniaxial compressive creep experiments. Eight types of specimens were fabricated and studied with a hydraulic loading equipment with different parameters, including water-to-binder ratio and fiber volume fraction. Based on the rheology theory, a fractional-differential linear model was introduced and successfully simulated the long-term responses of the PVA-ECC. Two existed fractional order Maxwell and integer-order linear models are compared. The experimental results demonstrate that the long-term creep magnitude increase rapidly within the first week and then tends to converge at 90 d under low stress level. The increase in w/b ratio has a negative effect on the specific creep of PVA-ECC. Moreover, PVA fiber can reduce the ultimate specific strain remarkably, and the specimens with 1% and 2% PVA fibers exhibit obviously decline of 29% and 34% in comparison with that of the specimen without PVA fibers. The whole linear viscoelastic behaviors of PVA-ECC can be fitted accurately with the proposed fractional order linear model and the fitting parameters present a clear mechanical significance. Rheological parameters viscosity ηA and fractional order α can reflect the time-depend features and flowing tendency of such multi-phase composites.

The manufacture of cement is considered as a high energy consumption and environmental pollution process, and it is necessary to figure out a way to reduce the consumption of cement in construction industry. The waste clay brick is a kind of construction waste with pozzolanic activity, which could be used to prepare blended cement after grinding. However, the particle size of clay brick powder (CBP) will influence its pozzolanic activity and properties of blended cement, which needs to be clarified. Therefore, in this study, the pozzolanic activity of CBP and properties of blended cement containing CBP were investigated. The results show that with the increase of grinding time, the CBP particles tend to be refined and spherical, which will increase the specific surface area and pozzolanic activity of CBP. The decrease of CBP particle size in blended cement paste can accelerate the early-age hydration and decrease the setting time since the ultrafine CBP could become the crystallization nucleus. The compressive strength of mortars with 30% CBP is 10%–35% lower than that without CBP, and the smaller the CBP particle size, the faster the compressive strength grows. Moreover, the hydration products and pore structure results also prove that the CBP with smaller particle size will consume more calcium hydroxide to react, which could make the microstructure denser and obtain stronger compressive strength growth at later ages. Meanwhile, the environmental impact and cost calculations indicate that the energy intensity and CO2 emissions of blended cement are obviously lower than Portland cement. It could be concluded that the pozzolanic activity of CBP will be enhanced with the decrease of particle size, and this research provided the reference for application of waste clay brick to produce green construction materials.

Pretreatment is very important for the application of phosphogypsum (PG), but it is seldom adopted in practise due to high investment and costs. In order to promote the application of PG, post treatment of hemihydrate phosphogypsum (HPG) by addition of slaked lime (SL) was investigated. As an alkaline additive, SL can neutralize HPG. In addition, the interaction of HPG and SL can not possibly be avoided, because SL is generally presented in composite binder and it is also the hydration product of cement based materials which are widely used. Therefore, the hydration process, setting and hardening characters of HPG with different SL contents at a constant water/powder ratio were studied in detail. It was found that small amounts of SL can neutralize HPG but lead to super retardation and strength degradation due to the formation of calcium phosphate which would hinder the dissolution of HPG and alter the morphology of gypsum from needle-like to tiny crystal with little interlocking. Surprisingly, the addition of excessive SL regardless of pH would promote the rehydration of HPG and eliminate the influence of calcium phosphate contributing to the comparable strength and normal setting possibly due to the preferential precipitation mechanism of calcium phosphate. This important finding could be translated into specific design guidelines for post treatment.

Graphdiyne can serve as both the electron‐acceptor and electron‐donor due to its distinct topological and electronic structure. The unique electron‐transfer behavior promotes its widespread applications. In article number 1800959, Dan Wang and co‐workers discuss advances in how graphdiyne and its composite materials are used for photo‐ and electrochemical energy conversion areas, such as solar cells, photocatalysis, water splitting, and fuel cells.

As a rising star of carbon allotropes, graphynes (GYs) merely consist of sp‐ and sp2‐hybridized carbon atoms, which endow them a large conjugated network and expanded 2D porous structure. With unique topological structure, GYs display unusual semiconducting properties, especially in the aspects of charge mobility and electron transport. Among the members of the GY family, only graphdiyne (GD) can be successfully synthesized in large quantities. The advanced properties of GD make it promising in various applications. Here, the recent progress in the synthesis of GD and GD‐based composites is reviewed as well as their applications in photorelated and electrocatalytic applications. It is hoped that this Review will promote the development and applications of carbon chemistry.