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Photocatalytic oxygen reduction reactions and water oxidation reactions are extremely promising green approaches for massive H2O2 production. Nonetheless, constructing effective photocatalysts for H2O2 generation is critical and still challenging. Since the network topology has significant impacts on the electronic properties of two dimensional (2D) polymers, herein, for the first time, we regulated the H2O2 photosynthetic activity of 2D covalent organic frameworks (COFs) by topology. Through designing the linking sites of the monomers, we synthesized a pair of novel COFs with similar chemical components on the backbones but distinct topologies. Without sacrificial agents, TBD‐COF with cpt topology exhibited superior H2O2 photoproduction performance (6085 and 5448 μmol g−1 h−1 in O2 and air) than TBC‐COF with hcb topology through the O2‐O2⋅−‐H2O2, O2‐O2⋅−‐O21‐H2O2, and H2O‐H2O2 three paths. Further experimental and theoretical investigations confirmed that during the H2O2 photosynthetic process, the charge carrier separation efficiency, O2⋅− generation and conversion, and the energy barrier of the rate determination steps in the three channels, related to the formation of *OOH, *O21, and *OH, can be well tuned by the topology of COFs. The current study enlightens the fabrication of high‐performance photocatalysts for H2O2 production by topological structure modulation. [ABSTRACT FROM AUTHOR]

As the power‐conversion efficiency (PCE) of organic–inorganic lead halide perovskite solar cells (PSCs) is approaching the theoretical maximum, the most crucial issue concerns long‐term ambient stability. Here, the application of PCN‐224 quantum dots (QDs) is reported, a typical Zr‐based porphyrinic metal–organic framework (MOF), to enhance the ambient stability of PSCs. PCN‐224 QDs with abundant Lewis‐base groups (e.g., CO, C−N, CN) contribute to high‐quality perovskite films with enlarged grain size and reduced defect density by interaction with under‐coordinated Pb2+. Meanwhile, PCN‐224 QDs enable the well‐matched energy level at the perovskite/hole transport layer (HTL) interface, thereby facilitating hole extraction and transport. More importantly, PCN‐224 QDs‐treated HTL can capture Li+ from bis(trifluoromethanesulfonyl)imide additive, leading to the reduced aggregation and less direct contact with moisture for hygroscopic Li‐TFSI. Moreover, PCN‐224 QDs mitigated Li+ ion migration into the perovskite layer, thus avoiding the formation of deleterious defects. The resultant devices yield a champion PCE of 22.51%, along with substantially improved durability, including humidity, thermal and light soaking stabilities. The findings provide a new approach toward efficient and stable PSCs by applying MOF QDs. [ABSTRACT FROM AUTHOR]

By using the methods of bibliometric and content analysis, this paper conducted data mining and content research on the articles of advertising design research in China from 1992 to 2020 and analyzed the evolution context, hotspots, and sustainable development trends of advertising design research in recent 30 years. It was found that advertising design research has experienced four stages: embryonic, exploration, prosperous, integration and innovation. It mainly focused on four hotspots: collaborative research on relevant factors of advertising design, research on advertising design centered on plane media, renewal of concept and method of advertising design education, and research on advertising design and communication in the new media environment. This paper analyzed and predicted five future sustainable research directions: research on the profound transformation of advertising media in the digital age, research on nationalization theory and localization practice of advertising design, international academic dialog in the field of advertising design, research on advertising design education under the background of interdisciplinary, and sustainable social value innovation. [ABSTRACT FROM AUTHOR]

High‐entropy carbides (HECs) are of great interest as they are promising candidates for ultra‐high‐temperature and high‐hardness applications. To discover carbides with enhanced yield strength and hardness, mechanism‐based design approaches are needed. In this study, dislocation core atomic randomness as a mechanism for hardness enhancement is proposed, in which the random interactions between different elements at a dislocation core make it more difficult for the dislocation to slip. The Peierls stress of an a/2⟨11¯0⟩{110} edge dislocation is calculated based on density functional theory, in which atomic randomness is increased by increasing the number of elements at the dislocation core. The results show that the Peierls stress statistically increases with increasing number of elements, indicating that incorporating more elements is likely to produce higher hardness. Based on this guiding principle, three eight‐cation HECs are fabricated (Ti,Zr,Hf,V,Nb,Ta,X,Y)C (X,Y = Mo,W, Cr,Mo, or Cr,W), the composition of which is guided by ab initio calculations of their formation enthalpy and entropy forming ability. The single‐phase dense ceramics all show high nanoindentation hardness of around 40 GPa. The random interactions between different elements at a dislocation core provide a mechanism for improving the hardness of structural ceramics. [ABSTRACT FROM AUTHOR]

High entropy ceramics are novel materials with no less than four different cations or anions. The development of high entropy ceramics follows the 'configurational entropy stabilized single phase' concept, which was first demonstrated for high entropy metal alloys in 2004. The advantages of high entropy ceramics are their compositional and structural diversity, and many of them have a band gap, which makes them potential functional materials for a wide range of applications. They have recently generated significant interest with the publication of 70+ related papers since 2015. In this review we have summarized the recent progress in this rapidly growing field. We emphasize the progress by researchers to answer the following three fundamental questions for high entropy ceramics: (1) which combinations of cations or anions can be synthesized as single-phase materials; (2) are the component elements truly random down to the atomic scale; and (3) what new physics, properties and applications will the incorporation of multi-elements elements bring. These fundamental questions are still open at this stage and warrant further studies. The objective of this review is to give a comprehensive overview of the literature to date on high entropy ceramics and to guide further investigation in this emerging field. [ABSTRACT FROM AUTHOR]

We demonstrate the use of elemental precursors Cu, Fe, Sn, and S to obtain a mawsonite (Cu6Fe2SnS8)/stannite (Cu2FeSnS4) composite using a solid-state process at ambient temperature in an industrial eccentric vibration mill for up to 240 min in argon atmosphere. The samples were characterized using various analytical techniques such as x-ray diffractometry, scanning electron microscopy, energy-dispersive x-ray spectroscopy, and nitrogen adsorption and magnetic measurements. For thermoelectric measurements, the properties of samples densified via spark plasma sintering were measured using standard methods needed to calculate the figure of merit. The transformation of elemental precursors to a composite mixture proceeds relatively rapidly via several intermediate steps. The kinetics of this transformation is also in good agreement with the results for the unconsumed sulfur content in the reaction mixtures and can also be correlated with the magnetization results. Based on the thermoelectric measurements of the sample milled for 240 min, the calculated figure of merit reached a value of zT = 0.51 at 623 K due to a very low lattice thermal conductivity of 0.29 W/m-K and moderate power factor of 3.3 μW/cm-K2. The thermoelectric results obtained for the material are comparable to previously published values for pure mawsonite prepared from elements by laboratory ball milling. [ABSTRACT FROM AUTHOR]

TiO2/g-C3N4/MoS2 nanocomposite photocatalysts were synthesized via two-steps in situ solvothermal method. The nanocomposites exhibit an extended visible-light photoresponse, higher efficiency of charge carriers separation, and improved photocatalytic degradation of methylene blue (MB). TiO2/g-C3N4/MoS2 nanoparticles enjoys much higher degradation ratio (95%) under visible light illumination for 30 min than P25 (63%), TiO2/g-C3N4 (45%) and TiO2 (26%). The heterojunctions of TiO2/g-C3N4 and TiO2/MoS2 play a main role in the enhanced photocatalytic performance. The electrons generated in MoS2 and g-C3N4 under visible light migrate to the conduction band of TiO2 to degrade MB dye. The heterojunctions can enhance the separation of photogenerated electron-hole pairs and improve the utilization of photons. This work demonstrates that synergetic effect of g-C3N4 and MoS2, which is a good choice to improve the utilization of visible light of TiO2-based materials. [ABSTRACT FROM AUTHOR]

Cellular foams are widely applied as protective and energy absorption materials in both civil and military fields. A facile and simple one-step heating method to fabricate polymeric foams is measured by adopting thermally expandable microspheres (TEMs). The ideal foaming parameters for various density foams were determined. Moreover, a mechanical testing machine and split Hopkinson bar (SHPB) were utilized to explore the quasi-static and dynamic compressive properties. Results showed that the cell sizes of the as-prepared TEMs foams were in the micrometer range of 11 μm to 20 μm with a uniform cell size distribution. All the foams exhibited good compressive behavior under both quasi-static and high strain rate conditions, and were related to both foam densities and strain rates. The compressive strength of the TEMs foams at 8400 s−1 was up to 4 times higher than that at 10−4 s−1. The effects exerted by the strain rate and sample density were evaluated by a power law equation. With increasing density, the strain rate effect was more prominent. At quasistatic strain rates below 3000 s−1 regime, initial cell wall buckling and subsequent cellular structure flattening were the main failure mechanisms. However, in the high strain rate (HSR) regime (above 5000 s−1), the foams were split into pieces by the following transverse inertia force. [ABSTRACT FROM AUTHOR]

Cu–S based compounds are eco-friendly minerals, and some of them are potential thermoelectric materials for mid temperature range usage. These minerals belong to a large family, in which many compounds have never been investigated as thermoelectric materials. In this work, by using high-throughput screening based on several crystal structure features, we identified thirteen compounds as potential thermoelectric materials from the Inorganic Crystal Structure Database (ICSD), out of which nine of the compounds' thermoelectric properties have not been reported. Using ball milling mechanical alloying and spark plasmas sintering, Cu6Fe2S8Sn1 (mawsonite) and Cu16Fe4.3S24Sn4Zn1.7 (stannoidite) were successfully fabricated as single phase dense ceramics, and the zT values of these non-doped compounds are 0.43 and 0.24 @ 623 K, respectively. The screening criteria were also rationalized by establishing “structure–property relationships” and the topological similarity of the thirteen identified compounds was investigated. [ABSTRACT FROM AUTHOR]

Energy filtering effect is usually utilized in composites to enhance the thermoelectric performance, and a reliable theoretical approach is needed to predict the optimum parameters related to this effect. By taking Bi2Te3 as an example, we show that first principles calculations and Boltzmann transport equations can be used to evaluate energy filtering effect, and the optimal values for the maximum power factor of interfacial potential barrier height ( Eb) and carrier scattering probability ( p) can be calculated precisely. The calculation results show that the power factor can be greatly enhanced at high carrier concentrations by energy filtering. This enhancement is sensitive to Eb and p: to achieve 40% power factor enhancement, Eb must be in the range 0.06-0.10 eV, and p should be greater than 60%. The optimal Eb also shows weak dependence on p. Our approach can be easily applied to other materials due to the generality of first principles calculations, and will aid high throughput screening for new thermoelectric composites. [ABSTRACT FROM AUTHOR]

Biomass gasification is proving to be an alternative technology to the use of fossil fuels for energy production. The article considers the bench-scale, air-blown updraft gasification of biomass wood pellets. The objective of the study was to understand the characteristics of evolved gases from the gasifier that was built and assembled at the University Laboratory. Wood pellets of diameter 5 mm, length between 5 and 20 mm constitute the feedstock used. The experimental investigation reveals the major gases produced are CO2, CO, and H2, while CH4and other hydrocarbons are minor. However, the gasifier used is initially preheated to a temperature of about 800°C. This is indicated by the thermo-couple readings (T1–T8) with T6 as the standard thermo-couple. When T6 attains a steady state at 800°C, the gasifier is turned into a self-sustaining gasification condition. The entire experiment takes about four (4) hours to complete and this gives an understanding of evolved gases from the entire gasification process in the inside of the batch-scale updraft gasifier. [ABSTRACT FROM PUBLISHER]

Dioxins emission is a serious problem during thermal utilization of municipal solid waste (MSW). The key structure in dioxins is CACl bond, so controlling the formation of chlorinated hydrocarbons, which contain CACl bond, is very important. PVC, a main source of chlorine in MSW, was used as fuel in this work. Chlorinated hydrocarbons were released from PVC pyrolysis process. A hot-rod reactor combined with a homogeneous conversion stage was established in an attempt to realize the concept of utilizing the hydrogen, which was also released from PVC pyrolysis process, to control the formation of chlorinated hydrocarbons. In the experiments, the influences of temperature, concentration of hydrogen and residence time in the homogeneous conversion stage on the formation of chlorinated hydrocarbons were investigated. Some results were concluded as follows, first, during PVC pyrolysis progress, H2, Cl2, HCl, hydrocarbons and chlorinated hydrocarbons would be released so that the dechlorination reaction and the chlorination reaction occurred in the homogeneous conversion stage. Second, the concentration of hydrogen released during PVC pyrolysis process was enough as opposed to the release of chlorine. Third, elevating the temperature of homogeneous conversion could promote the dechlorination reaction. Increasing the concentration of hydrogen had the same effect. Fourth, enough residence time in the homogeneous conversion stage could ensure the dechlorination reaction completely to occur. In a word, the results suggested that utilizing hydrogen released from PVC pyrolysis could control the formation of chlorinated hydrocarbons effectively when the temperature of the homogeneous conversion stage was over 7008C with residence time more than 1.5 s. [ABSTRACT FROM AUTHOR]

Experiments of nitric oxide reduction by the tar-included syngas from a small biomass updraft gasifier have been carried out on a tubular reactor under a temperature range of 900 to 1200°C. The initial mole fraction of NO was 1000 ppm and that of the oxygen and gasification syngas were varied. Comparison of the reburning results of the present syngas with other fuels clarified the influence of tar. Under the conditions of this work, the participation of tar compounds in NO reduction mainly begins with cracking into light hydrocarbons which is sensitive to both the oxygen concentration and the temperature. Tar leads to a satisfactory NO-reduction improvement under relative oxygen-rich conditions, supplying extra hydrocarbon radicals and creating a more appropriate atmosphere for reburning reactions. As for a reductive environment, little benefit was gained from the presence of tar. The rise of temperature brings a clear promotion only to NO reduction with a high oxygen flow rate, while polymerization should be concerned for a low oxygen flow rate. It is believed that a substantial portion of tar converts to acetylene through cracking under suitable reburning conditions, resulting in an active NO-reduction reaction pathway. © 2013 American Institute of Chemical Engineers Environ Prog, 33: 602-608, 2014 [ABSTRACT FROM AUTHOR]

Perovskite SnTiO3 (SNO) was predicted to be ferroelectric with a large spontaneous polarization. However, the perovskite phase SNO was found to be metastable in experiments. Here, we show that SNO perovskite phase can be stabilized by the interfacial geometry in ATiO3/SNO superlattices (A = Ca, Sr, Ba) of short periodicity using first principles calculations. We found that CaTiO3/SNO superlattice has the largest polarization. In all the superlattices investigated, a phase transition from tetragonal to monoclinic structure was found with increasing in-plane lattice constants. Accompanying this phase transition, polarization directions rotate from [001] to [110], which is promising for achieving large piezoelectric responses. [ABSTRACT FROM AUTHOR]

Abstract: Boltzmann transport equations and density functional theory calculations were employed to calculate the thermoelectric transport coefficients of CaTiO3, SrTiO3 and BaTiO3. It was found that BaTiO3 has the largest Seebeck coefficient and power factor. Then the transport coefficients were analyzed using the ‘Tight Binding Model’. The band narrowing, caused by the increasing lattice constants from CaTiO3 to BaTiO3, was the main reason for the increasing Seebeck coefficients and the decreasing electrical conductivity. The calculated electrical conductivity and electronic thermal conductivity were in line with the Wiedemann–Franz law and the Lorenz factor was determined to be 2.45 for these oxides as degenerate semiconductors. Our theoretical results are helpful for seeking high performance thermoelectric oxides. [Copyright &y& Elsevier]

Abstract: A novel approach was developed to calculate temperature-dependent Seebeck coefficient of heavily doped systems. The electronic density of states (DOS) and Fermi energy were determined and then, using these two parameters, the Seebeck coefficient was calculated by using Boltzmann transport theory. This approach is applied to heavily La-doped SrTiO3. The calculated Seebeck coefficient agrees well with the experimental data. By analyzing the results, it was shown that Seebeck coefficient is greatly affected by the asymmetry of DOS with respect to Fermi energy. [Copyright &y& Elsevier]

Due to the promotion on Cl radical generation by enhanced oxidation, chlorination of hydrocarbon intermediates becomes a potential formation path for chloroaromatic precursors of PCDD/Fs (polychlorinated dibenzo-p-dioxins and dibenzofurans) in both MSW (municipal solid waste) incineration and gasification-combustion processes, in which intrinsic oxygen might have a significant effect on the competition between oxidation and chlorination. Thus, chlorination of benzene and phenol was experimentally studied on a homogeneous flow reaction system. Effects of temperature and ER (equivalence ratio) were assessed, and comparison was carried out to clarify the alteration in formation behaviors of chloroaromatics by extrinsic and intrinsic oxygen. At 600 °C, chlorobenzenes were already largely formed in benzene chlorination, and the addition of extrinsic oxygen barely affected it. On the contrary, with intrinsic oxygen, phenol tended to decompose to light compounds. With rising temperature, oxidation was promoted and extrinsic oxygen strongly inhibited the formation of chloroaromatics in benzene chlorination at 900 °C and higher temperature. For phenol chlorination, chlorobenzenes were still rarely generated. However, high proportions of octachloronaphthalene and octachlorodibenzofuran were observed, due to the enhancement in polymerization by high temperature. When increasing ER, oxidative decomposition was also promoted in both the chlorination of benzene and phenol. Extra extrinsic oxygen led to a further reduction of chloroaromatics during benzene chlorination, and till ER = 1.0 at 1000 °C, comparable performance to intrinsic oxygen could be achieved in the control of chloroaromatics. Based on these results, formation pathways of the major chloroaromatics from chlorination, oxidation and polymerization were summarized, and the roles of extrinsic and intrinsic oxygen in altering their formation behaviors were revealed. Image 103560 • Intrinsic O clearly inhibited the formation of chloroaromatic under low temperature. • High temperature clearly promoted the inhibition of chloroaromatic by extrinsic O 2. • With intrinsic O, high temperature led to high proportion of polymerization product. • O 2 achieved comparable performance to intrinsic O at high temperature and high ER. • Major formation pathways of chloroaromatics in chlorination reaction were concluded. [ABSTRACT FROM AUTHOR]

We present a modified surrounding-gate metal–oxide–semiconductor field effect transistor (MOSFET), in which the gate consists of two metals with different work functions, and single-halo doping is added to the channel near the source end. The performance of the modified structure was studied by developing physics-based analytical models for the surface potential, electric field, and threshold voltage. It is shown that the novel MOSFET could significantly reduce threshold voltage roll-off and drain-induced barrier lowering, and simultaneously improve carrier transport efficiency by carefully configuring the halo doping and work functions of the dual-material gate. The results predicted using the models are compared with those obtained with the three-dimensional simulator Davinci to verify the accuracy of the proposed analytical models. [ABSTRACT FROM AUTHOR]

Photocatalytic oxygen reduction reactions and water oxidation reactions are extremely promising green approaches for massive H 2 O 2 production. Nonetheless, constructing effective photocatalysts for H 2 O 2 generation is critical and still challenging. Since the network topology has significant impacts on the electronic properties of two dimensional (2D) polymers, herein, for the first time, we regulated the H 2 O 2 photosynthetic activity of 2D covalent organic frameworks (COFs) by topology. Through designing the linking sites of the monomers, we synthesized a pair of novel COFs with similar chemical components on the backbones but distinct topologies. Without sacrificial agents, TBD-COF with cpt topology exhibited superior H 2 O 2 photoproduction performance (6085 and 5448 μmol g -1  h -1 in O 2 and air) than TBC-COF with hcb topology through the O 2 -O 2 ⋅ - -H 2 O 2 , O 2 -O 2 ⋅ - -O 2 1 -H 2 O 2 , and H 2 O-H 2 O 2 three paths. Further experimental and theoretical investigations confirmed that during the H 2 O 2 photosynthetic process, the charge carrier separation efficiency, O 2 ⋅ - generation and conversion, and the energy barrier of the rate determination steps in the three channels, related to the formation of *OOH, *O 2 1 , and *OH, can be well tuned by the topology of COFs. The current study enlightens the fabrication of high-performance photocatalysts for H 2 O 2 production by topological structure modulation., (© 2024 Wiley-VCH GmbH.)

Pinus is an economically and ecologically important genus whose members are dominant components globally in low-latitude mountainous and mid-latitude temperate forests. Pinus species richness is currently concentrated in subtropical mid-low latitudes of the Northern Hemisphere, differing from the latitudinal diversity gradient mostly recognized in woody angiosperms. How the present pattern was developing in Earth's past is still poorly studied, particularly in eastern Asia. Here, a new fossil species, Pinus shengxianica sp. nov. is described based on a fossil seed cone from the Late Miocene Shengxian Formation in Zhejiang, southeast China. A co-occurring cone is recognized as a known fossil species, Pinus speciosa Li. Extensive comparison of extant and fossil members of Pinus suggests P. shengxianica shares a striking cone similarity to Pinus merkusii and Pinus latteri (subsection Pinus ) from tropical Southeast Asia in having annular bulges around the umbo on the apophysis. The morphological resemblance indicates these two extant low-latitude pines probably possess a close affinity with the present newly-discovered P. shengxianica and originated from East Asian mid-low latitude ancestors during this generic re-diversification in the Miocene. This scenario is consistent with the evolutionary trajectory reflected by the pine fossil history and molecular data, marking the Miocene as a key period for the origin and evolution of most extant pines globally. The co-occurrences of diverse conifers and broadleaved angiosperms preferring diverse niches demonstrate Late Miocene eastern Zhejiang was one of the hot spots for coniferophyte diversity and hosted a needled-broadleaved mixed forest with complex vegetation structure and an altitudinal zonation., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2022 Kunming Institute of Botany, Chinese Academy of Sciences. Publishing services by Elsevier B.V. on behalf of KeAi Communications Co. Ltd.)