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Research on asphalt fatigue and self-healing performance can more accurately model the damage and self-healing evolution principles in practical applications. In order to analyze the rationality of evaluation indexes based on rheology to evaluate the self-healing properties of TPU modified asphalt, a dynamic shear rheometer (DSR) was used in this study to perform time, temperature, and frequency sweep tests of TPU modified asphalt for analyzing the fatigue self-healing properties of TPU modified asphalt over a broader range of temperatures and loading frequencies. This method can improve the accuracy of the fatigue failure determination criteria of TPU modified asphalt and clarify the material performance parameters of TPU asphalt modifiers. The results showed that the increase in hard segment content (C h) and isocyanate radical index (r) can effectively alleviate the decrease in shear deformation resistance of modified asphalt caused by the increase in N (load repetition). N f50 (the number of loads when the normalized modulus drops to 0.5) is more suitable to evaluate the fatigue life of TPU modified asphalt compared with N p20 (the number of loads when the DER - N curve is offset by 20% deviation from the linear undamaged line) and N 2 (the number of load times corresponding to the intersection point of the tangent line of the DER – N fitted curve and the undamaged line). The degree of self-healing will also increase with the increase in C h and r. Besides, the higher the healing temperature and the healing time, the longer the fatigue life. The effects of the self-healing evaluation index (HI) on the self-healing index of TPU modified asphalt were as follows: healing temperature > healing time > soft segment > C h > r > degree of damage > degree of aging > deg r ee of self-healing. • The effects of different segments of polyurethanes on the fatigue self-healing ability of modified asphalt were analyzed. • A viscoelastic master curve for comprehensive analysis of wide temperature and wide frequency bands was established. • The versatility and accuracy of N f50 as an evaluation index for the fatigue life of TPU modified asphalt were determined. • Through comparative experiments, the appropriate synthesis parameters and dosage of TPU asphalt modifier were determined. • The effects of factors on the self-healing index HI were analyzed and sorted by gray correlation coefficient. [ABSTRACT FROM AUTHOR]

• Numerical analysis of the performance of a new fishtail-type stirrer. • PIV experiments validate the correctness of the model. • Compared to the RT impellers, fishtail impeller reduce power consumption by 16.4 %. • Compared to the RT impeller, fishtail impellers are effective in reducing mixing times and increasing mixing efficiency. • The fishtail impeller increases the pumping flow by 13.5 % and the pumping efficiency by 27.66 % compared to the RT impeller. In this study, a new fishtail impeller was introduced to improve the mixing of fluids in the stirred tank. The validity of the numerical model was first demonstrated by PIV experiments. Secondly, the CFD technique was used to analyze and predict the flow field characteristics in the stirred tank. Also, the effect of blade inclination on the mixing effect is analyzed. Finally, a comparative Analysis with the whale tail impeller is carried out to demonstrate the superiority of this research work. The results show that The results of the study showed that the power number of the fishtail impeller was reduced by 16.4 % compared to the RT impeller. The pumping efficiency of the fishtail impeller was increased by 25.52 %. The results also show that increasing the blade inclination increases the turbulent kinetic energy in the stirred tank. Comparative analysis with the whale-tail impeller reveals that the power number of the fish-tail impeller is reduced by 17.2 % and the pumping efficiency is increased by 19.97 %. [Display omitted] [ABSTRACT FROM AUTHOR]

Two novel bipolar isomers, namely 3,5-bis(3-(9 H -carbazol-9-yl)phenyl)isonicotinonitrile ( m -DCzPyCN), and 3,5-bis(9-phenyl-9 H -carbazol-3-yl)isonicotinonitrile (3-DCzPyCN), are designed and synthesized by selecting cyanopyridine as n-type unit and N -phenylcarbazole as p-type unit. Two peripheral carbazoles are conjugated through their C-3 atom with the central cyanopyridine in 3-DCzPyCN but are indirectly linked through the N-9 atom via meta -phenylene bridges in m -DCzPyCN. The linking strategy had significant effect on the physical properties of the isomers. The single-carrier device study reveals that 3-DCzPyCN has much better positive and negative charge balancing ability than m -DCzPyCN. The 3-DCzPyCN hosted green phosphorescent organic light-emitting diode exhibits superior performance over m -DCzPyCN, with the maximum current efficiency of 84.1 cd A −1 and external quantum efficiencies of 24.2% and low efficiency roll-off. At an extremely high brightness of 10000 cd m −2 , the efficiency still remained at 78.4 cd A −1 , which corresponds to a roll-off of 6.7% from the maximum value. Even at an ultra-high brightness of 100000 cd m −2 , the efficiency is reduced by 47.0%. The superior performance of 3-DCzPyCN is ascribed to its remarkable charge balancing capability, which is the combined result of the cyanopyridine as n-type unit and the conjugated linking strategy between p- and n-type moieties. [ABSTRACT FROM AUTHOR]

• Hosts with TADF, conventional fluorescence and RTP characters are developed. • Exciton utilization efficiency is improved by the host with TADF character. • An EQE of 36.1% was achieved for sky blue OLED with DspiroAc-TRZ as emitter. • An EQE of 34.0% was achieved for the sensitized device with v -DABNA dopant. Spiral donor units have attracted extensive research focuses in designing highly emissive thermally activated delayed fluorescence (TADF) emitters. Herein, to reveal the significance of spiral donor units for constructing highly efficient host materials, several spiral donor-based host materials are developed. With the incorporation of spiral donor, increased intermolecular distance is achieved to reduce the concentration quenching effect of dopant. Moreover, the high triplet energy level of spiral donor can provide an additional energy transfer channel to further improve the device performance. Noteworthy, by connecting spiral donors or conventional carbazole unit with different electron-withdrawing units phenoxathiine 10,10-dioxide (PX) or phenoxathiine (PA), these hosts are given different photophysical properties of TADF, room-temperature phosphorescence (RTP) and conventional fluorescence (CF). The strong electron-withdrawing ability of PX is beneficial to the TADF character of spiral donor-based molecules, while the weak electron-withdrawing ability of PA is beneficial to the RTP property. Consequently, the blue OLEDs with DspiroAc-TRZ as a dopant emitter based on the hosts with TADF characters exhibit higher performance than those with RTP and CF properties, and excellent external quantum efficiency (EQE) of 36.1 % and current efficiency of 84.6 cd/A are achieved in a simple device structure. Furthermore, peak EQEs of 34.0 % and 33.0 % are achieved, when DspiroS-PX and DspiroS-PA hosted DspiroAc-TRZ are used to sensitize blue multi-resonance TADF emitter v -DABNA. Our work may shed new light on designing highly efficient host materials for TADF emitters. [ABSTRACT FROM AUTHOR]

For bootstrap sample sums resulting from a sequence of random variables { X n , n ≥ 1 } , a very general central limit theorem is established. The random variables { X n , n ≥ 1 } do not need to be independent or identically distributed or to be of any particular dependence structure. Furthermore, no conditions, including moment conditions, are imposed in general on the marginal distributions of the { X n , n ≥ 1 } . As a special case of the main result, a result of Liu (1988) concerning independent but non-identically distributed { X n , n ≥ 1 } is extended to a larger class of parent sequences. A version of the main result is also presented wherein the bootstrap sample sums have random bootstrap sample sizes. [ABSTRACT FROM AUTHOR]

A cubic Mn 0.6 Fe 0.4 S solid solution material has been synthesized using a scalable in situ sulfuration treatment of Prussian-blue analogs (PBAs), and its phase formation process and Li-storage mechanism were investigated. Increased treatment temperature and time encourage a phase transformation from hexagonal Fe 7 S 8 to cubic FeS 2 during the sulfuration process, which results in the formation of a solid solution between cubic FeS 2 and cubic MnS. The resulting Mn 0.6 Fe 0.4 S solid solution electrode exhibits high initial coulombic efficiency, excellent rate performance, and superior cycling stability (520 mA h g−1 after 1000 cycles at 1.0 A g–1). Ex-situ X-ray diffractometry and electro-kinetics tests show that the doping-induced structural phase transition in Mn 0.6 Fe 0.4 S solid solution creates a favorable electronic structure and ensures rapid charge transfer kinetics during the lithiation/delithiation process, simultaneously achieving high energy conversion efficiency and a long lifespan. [Display omitted] • Cubic Mn 0.6 Fe 0.4 S solid solution as anode material is successfully synthesized. • The phase transition from α-MnS to metastable β-MnS could be induced in the charge process. • The improvement in electrochemical performance is attributed to the doping-induced structural phase transition in Mn0.6Fe0.4S. [ABSTRACT FROM AUTHOR]

The steam-diluted oxyfuel combustion of the hydrogen-enriched fuels is promising to attain zero-emission in the energy system. One critical challenge for this technology is the flame stabilization, which was examined in this work mainly through the flame structure analysis. The burner adopted three swirlers to enhance the mixing, which leads to V-shaped diffusion-like flames. Starting from the purely hydrogen fuel, the CH 4 addition effects with fractions of 20% and 40% were studied. Meanwhile, combustion with different equivalence ratios were also compared, when the volume flowrate ratio of the O 2 and steam was kept constantly at 1:4. For these diffusion-like flames, the reaction zone was obtained using the OH-PLIF. Then, the flame structure statistics, such as the number and area of the broken reaction zone and its thickness, were all examined. Results show that the fuel properties and steam flowrate intensively affect the flame stabilization. With increased CH 4 addition in the hydrogen fuel, the reaction zone tends to be broken seriously. This is characterized by frequently appeared small reaction zone fragments, along with largely decreased reaction zone area. With a larger stream flow rate, the local flame extinction is also increased obviously and the flame branches can be completely distinguished due to the intensive straining effects. The extinction upstream is observed to promote an enveloped reaction zone downstream, due to the unburned fuel leakage. It is found that the mean reaction zone thickness is overall close, which varies from 1 to 2 mm, but can be modified by different factors. An analogical comparison of the reaction thickness to the laminar counter-flame thickness reveals that the CH 4 addition and flow straining can decrease the reaction zone thickness, but the accompanied turbulence effects can broaden it to at least about 1.2 times. These results are beneficial to attain a stable ultra-clean combustion utilizing hydrogen-based flexible fuels. [Display omitted] • Steam-diluted swirling CH 4 /H 2 /O 2 flames are studied. • The flame is a diffusional type and can be unstable. • Extinction is increased with either CH 4 addition or high steam flowrate. • Extinction and fuel leakage lead to enveloped reaction zone downstream. • The reaction zone thickness can be broadened by turbulence. [ABSTRACT FROM AUTHOR]

• Zn 2 Ti 3 O 8 /ZnTiO 3 and Zn 2 TiO 4 /R-TiO 2 heterostructures were prepared through a two-step chemical route. • The heterostructure catalysts showed improved photocatalytic activities for CO 2 reduction with H 2 O. • Zn 2 Ti 3 O 8 /ZnTiO 3 and Zn 2 TiO 4 /R-TiO 2 heterojunctions favor the separation and transfer of charge carriers. • The band gap structures and the working mechanisms of Zn 2 Ti 3 O 8 /ZnTiO 3 and Zn 2 TiO 4 /R-TiO 2 heterojuntions were proposed. Photocatalytic reduction of CO 2 with H 2 O on photocatalysts to produce fuels presents great potential to simultaneously address energy and environmental issues. Herein, zinc titanate-based heterostructured nanohybrids including Zn 2 Ti 3 O 8 /ZnTiO 3 and Zn 2 TiO 4 /R-TiO 2 were designed and prepared through a two-step chemical route. When used as photocatalyst for converting CO 2 with H 2 O under UV-light irradiation, the zinc titanate-based heterostructured nanohybrids show high photocatalytic performance, with CH 4 and CO yields significantly higher than those obtained with Zn 2 Ti 3 O 8 , Zn 2 TiO 4 , and rutile TiO 2 as the photocatalysts. The existence of heterojunctions in the nanohybrids was demonstrated by experimental results, and electrochemical impedance spectra also reveal a favorable zinc titanate-based heterostructure. Moreover, based on theoretical calculations, the observed reduced band gap further revealed the effective light-absorption of the heterostructured nanohybrids in CO 2 reduction. It is thus concluded that the synergistic effect of the heterostructure promotes charge separation and fast electron transport, resulting in its enhanced photocatalytic performance in CO 2 reduction. [ABSTRACT FROM AUTHOR]

Incorporating pyridyl uniquely from its 2-position onto 10-site of acridone ring generated intramolecular hydrogen bond in a group of acridone-carbazole hybrid thermally activated delayed fluorescence emitters, which universally pulled down non-radiative transition rates by three orders and elevated reverse intersystem crossing rates by two orders, and thus boosted PLQYs to almost unity and EQEs of OLEDs to 30+%, representing the state-of-the-art efficiencies of deep-blue TICT-TADF materials and devices with CIEy≤0.10. [Display omitted] • Intramolecular-hydrogen-bond boosts performance of deep blue TADF emitters. • H-bond reduces k nr by 3 orders and increases k RISC by 2 orders. • PLQYs≈100 %, k RISC s ≥ 105 s−1 and horizontal orientation ratios ≥90 % are obtained. • Deep blue OLEDs exhibit record-high EQEs of 31–33 % with CIE y of 0.09–0.12. A group of D-A-D type thermally activated delayed fluorescence (TADF) emitters were developed with 10-(pyridin-2-yl)acridin-9(10 H)-one as acceptor and substituted carbazoles as donors. The design was focused on incorporating pyridyl to the 10-site nitrogen atom of acridin-9(10 H)-one ring, which improved the reverse intersystem crossing rate constant k RISC from 103 s−1 to 105 s−1. More importantly, the linkage of pyridyl uniquely from its 2-position to acridin-9(10 H)-one ring induced intramolecular hydrogen bond, which suppressed nonradiative transition rates by three to four orders of magnitude and universally increased the photoluminescence quantum yields from 54 % to nearly 100 %. In combination with the intrinsic high horizontal orientation ratios over 90 % of acridin-9(10 H)-one based molecules, such pyridyl decoration boosted the external quantum efficiencies of simple-structure deep blue organic light-emitting diodes to 31–33 % with CIE x of 0.15 and CIE y of 0.09 ∼ 0.12, being double of that for hydrogen-bond-free parent emitter and representing the state-of-the-art efficiencies for the deep blue twisted intramolecular charge transfer type TADF materials with CIEy ≤ 0.10 so far. These TADF emitters are comparable with the prevailing multiresonance blue emitters in terms of distinctive efficiencies, but advantageous in much facile syntheses. [ABSTRACT FROM AUTHOR]

A simple and one-step solvothermal synthesis method has been developed to prepare two-dimensional (2-D) hydrohausmannite ((Mn 4-2x Mn x )Mn 8 O 16-x (OH) x ) nanoplates with radial length of 300 nm and thickness of about 25 nm in a binary ethanediamine/water solvent system. The formation mechanism of hydrohausmannite is suggested. As an anode material for electrochemical capacitors, the plate-shaped hydrohausmannite not only displays a high specific capacity (215 at 0.1 A g −1 ) and good rate capability, but also shows good stable performance along with 94% specific capacity retained after 3000 cycle tests. The method can be easily controlled and expected to be applicable for the large-scale preparation of the 2-D hydrohausmannite. [ABSTRACT FROM AUTHOR]

[Display omitted] • Coexistence of intra-CT and inter-CT processes is realized for DPA-XA-TRZ. • Dual CT processes can be simultaneously enhanced by planar molecular skeleton. • Organic light-emitting diodes with external quantum efficiency of 21.9% is realized. • Efficiency of 31.7% is realized by DPA-XA-TRZ sensitized device with DMAc-BN dopant. Intramolecular charge transfer (intra-CT) and intermolecular charge transfer (inter-CT) are two general molecular design strategies of thermally activated delayed fluorescence (TADF) materials for organic light-emitting diodes (OLEDs). Herein, a diphenylamine (DPA) donor and a 2,4-diphenyl-1,3,5-triazine (TRZ) acceptor are connected by two planar units, non-conjugated 9,9-dimethyl-9 H -xanthene (XA) and conjugated dibenzo[ b,d ]furan (FR), to give D-σ-A type emitter DPA-XA-TRZ and D-π-A type emitter DPA-FR-TRZ. Coexistence of intra- and inter-CT is found for DPA-XA-TRZ and is readily tuned by various doping concentrations owing to the non-conjugated linkage. In contrast, DPA-FR-TRZ shows a dominant intra-CT characteristic due to the strong molecular conjugation. The planar molecular skeleton of DPA-XA-TRZ could not only enhance intramolecular electronic coupling, but also reduce steric hindrance and shorten intermolecular distance to enhance inter-CT process. A maximum external quantum efficiency (EQE max) of 21.9 % is achieved for the OLED device based on DPA-XA-TRZ, which is 2.5 times higher than that of DPA-FR-TRZ (8.4 %). DPA-XA-TRZ can also be utilized as an assistant host to sensitize multiple resonance TADF emitter DMAc-BN, and an EQE max of 31.7 % is realized owing to its dual CT processes and high reverse intersystem crossing rate (k RISC), which is significantly superior to the conventional mCBP host and mCBP:PO-T2T exciplex cohost. [ABSTRACT FROM AUTHOR]

• Nonlinear thermoacoustic instability is studied under broad conditions. • Five kinds of stable or unstable flame modes are observed. • Hopf bifurcations for the instability are captured either by changing U in or Φ. • Appearance of ORZ flame is expected to trigger the instability. • Stable combustion regime is wider with lower swirl number S. The nonlinear behavior of thermoacoustic oscillation for premixed swirl flames fueled with CH 4 /air mixtures is experimentally studied by changing the equivalence ratio Φ , combustor inlet bulk velocity U in and swirl number S. The nonlinear dynamic characteristics of the system are analyzed by the methods of phase space reconstruction, recurrence plot, Poincaré section and 0–1 test for chaos. Five kinds of flame modes are observed in the combustion system with the change of Φ , U in , and S , which are lean/rich blow-off, stable combustion, quasi-periodic oscillation, and limit cycle oscillation. Subcritical Hopf bifurcation of the oscillation is captured either by changing Φ or U in , and Φ and U in are found to have similar effects on the flame mode transition under specific operating conditions. It is observed that the appearance of flame in the outer circulation zone (ORZ) and the enhancement of its burning intensity are matched with the occurrence of quasi-periodic and limit cycle oscillations, respectively. It is examined that the lean/rich blow-off limits and oscillation range are extended with a larger S , and the stable combustion regime is wider with a smaller S. This study contributes to understanding the nonlinear thermoacoustic instability of swirl flames under broad flame conditions, which helps to develop effective instability prediction and control methods in stable, efficient, and low-emission gas turbines. [ABSTRACT FROM AUTHOR]

Selenium (Se) is an essential microelement for humans and a beneficial element for plants. Increasing grain yield and Se content simultaneously in crop is of great significance. In the present study, we hypothesize that the delay in the application of appropriate concentrations of Se contributes to increased grain yield and Se content. A two-year field experiment was conducted to investigate the effects of three concentrations of selenite (0, 5, or 20 g ha−1) sprayed at two stages (initial or peak flowering stage) on the yield, yield components, agronomic traits, photosynthetic characteristics, dry matter, and Se accumulation and distribution of common buckwheat plants. Results indicated that low concentration of Se promoted leaf photosynthesis more than higher concentration. The grain dry matter weight and Se content increased linearly with increasing Se application concentration. Delayed growth stages resulted in 2.65 and 1.66 times higher grain Se content in plants sprayed with low and high Se concentrations, respectively. Both Se application rate and spray time contributed significantly to grain yield. The grain produced under low-concentration spraying of Se at the IFS was safe for human consumption. In the present study, we suggest that foliar application of Se at 5 g ha−1 at the IFS is the most efficient way to improve grain Se accumulation and yield in common buckwheat. Future research may focus on quantifying the species of Se and localizing the Se element distribution in grains. [Display omitted] • Low Se rate (5 g ha−1) promoted the growth and grain yield of common buckwheat. • The delay of spraying stage increased the Se content in common buckwheat grain. • The interaction of Se rates and spraying stage significantly affected grain yield. • Se content in common buckwheat grain correlated positively with Se application rates. [ABSTRACT FROM AUTHOR]

A multi-sensitization strategy is proposed to develop highly efficient and low efficiency roll-off solution-processed single-emission-layer all-fluorescence white organic light-emitting diodes, resulting in significantly boosted Förster energy transfer from blue emitter and green sensitizer to the orange-red dopant and thus a recorded external quantum efficiency of 22.8%. [Display omitted] • Multi-sensitization strategy to boost FRET and block exciton loss. • Exciton utilization efficiency was improved by BDP-C-Cz with HLCT character. • An EQE of 26.8% for blue s-OLED was achieved with 70% Θ// of spin-coated EML. • An EQE of 22.8% was achieved for the multi-sensitized all-fluorescence s-WOLED. Limited by the inefficient energy transfer from blue thermally activated delayed fluorescence (TADF) material to the complementary color fluorescent dopant and unwanted charge trapping effect, it is challenging to achieve a spectrally stable, high efficiency and low efficiency roll-off solution-processed single-emission-layer (SEL) white organic light-emitting diodes (WOLEDs). Herein, a highly efficient solution-processed all-fluorescence SEL-WOLED with suppressed efficiency roll-off and stable electroluminescence spectra is achieved by introducing a hybridized local and charge-transfer (HLCT) orange-red emitter (BDP-C-Cz) and a TADF sensitizer (4CziPN) into an optimized blue TADF OLED. Specially, the adopted BDP-C-Cz emitter has a high molar absorption coefficient, whose absorption spectrum has a significant overlap with the emission spectra of 4CziPN and blue emitter. By additionally introducing 4CziPN as an assistant sensitizer of blue emitter, Förster energy transfer can be enhanced to give favorable exciton allocation and thus effectively blocks triplet exciton loss. Accordingly, a recorded external quantum efficiency of 22.8% and current efficiency of 60.0 cd/A were realized for the solution-processed SEL-WOLEDs, with color coordinates of (0.33, 0.44) and good color stability, providing a valuable guidance for the future development of simplified, high-efficiency and low-cost WOLEDs. [ABSTRACT FROM AUTHOR]

The performance enhancement of laser additive manufactured components depends on structural innovation and tailored printing, and the naturally optimized structures can provide inspiration for design and manufacturing. In this work, a layered TiB 2 /Ti6Al4V structure inspired by the biological structure of the Crysomallon squamiferum shell was designed and built by multi-material laser powder bed fusion (LPBF). The mechanisms for material densification, element diffusion, interfacial reaction, crystal growth and performance enhancement of multi-material LPBF-processed layered TiB 2 /Ti6Al4V parts were revealed by experiments and simulations. A strategy of process optimization by alternating appropriate printing parameters for metallic and ceramic materials yielded fully dense multi-material parts without discernible interfacial defects. The microstructure control showed that TiB whiskers were generated by the in-situ reaction between TiB 2 and Ti matrix, yielding a sound metallurgical bonding between dissimilar materials. The gradient elements and microstructures induced the gradually changed microhardness at the interface, thereby reducing the abrupt change and incoordination of microstructure and properties at the interface. The excellent flexural performance with a strength of 2033.2 MPa and a strain of 7.8% was obtained for the laser printed of TiB 2 /Ti6Al4V multi-material parts, revealing the contribution of the high interfacial bonding between layers to the performance enhancement. The internal crack propagation in laser-fabricated parts was fulfilled by crack deflection and multistage cracking, which extended the propagation path and increased the crack propagation energy. The flexural strength and ductility of LPBF-fabricated TiB 2 /Ti6Al4V multi-material parts were enhanced by the combined effects of the bio-inspired layered composite structure and the interior whiskers-structured reinforcement. This study sheds light on the manufacturing and strengthening of ceramic/metal multi-material using laser additive manufacturing technology. [Display omitted] • Fully dense layered ceramic/metal structure with good interfacial bonding was prepared by multi-material 3D printing. • Formation mechanisms of layered TiB 2 /Ti6Al4V multi-material parts were investigated by experiments and simulations. • Gradient distributions of elements, microstructures and microhardness at the interface were determined. • Mechanical properties were enhanced by the combined effects of bio-inspired layered composite and the whiskers-structured reinforcement. [ABSTRACT FROM AUTHOR]

[Display omitted] • Multiple CT channels and 3LE states contribute to the speedy k r and RISC processes. • High Θ and small FWHM are realized due to the rigid disk-like structure. • η r and η out above 30% are achieved owing to triplet exciton utilization and high Θ. • EQE above 10% was realized for the standard blue device based on BO3N. The efficiency of pure blue Organic light-emitting diodes (OLEDs) still needs to be improved, which is limited by the utilization of the forbidden transition triplet excitons and low light-out-coupling efficiency in devices. Herein, two blue emitters were developed through combining multiple diphenylamine (DPA) donors with an oxygen-bridged boron (DBA) or triphenyl triazine (TRZ) acceptor. Notably, a narrow-band deep blue emission with a peak of 423 nm and a Full-width at half-maximum (FWHM) of 34 nm is realized for the boron-based emitter in toluene solution. Thanks to their multiple Charge transfer (CT) channels and high orientated disk-like structure, high radiative transition rates (k r > 108 s−1) and high horizontal emitting dipole ratios (Θ > 80%) can be realized simultaneously. Meanwhile, the introduction of the peripheral DPA units can also provide multiple localized triplet (3LE) states for spin up-conversion of forbidden transition triplet excitons. Owing to the effective up-conversion of triplet excitons and high light-out-coupling efficiency, maximum external quantum efficiency of more than 10% is achieved for the boron emitter-based pure blue OLEDs with a Commission Internationale de l'Eclairage (CIE) coordinates of (0.14, 0.08). [ABSTRACT FROM AUTHOR]

The non-doped organic light-emitting diodes (OLEDs) based on thermally activated delayed fluorescence (TADF) materials are attracting increasing attentions due to the excellent performance and simple fabrication. We report an effective design strategy of TADF emitters to improve the non-doped performance by adjusting the valence state of the S atom in TADF molecules and utilizing the steric hindrance effect. Two novel TADF materials PT-BZ-DMAC and PS-BZ-DMAC were designed and synthesized with benzophenone acceptor and acridine donor. In particular, the thioether or sulfone group was attached to benzophenone. Remarkably, the bluish-green TADF-OLED with non-doped PT-BZ-DMAC turned on at 2.5 V and realized a maximum external quantum efficiency (EQE) of 17.34%, which was comparable with its doped OLED (17.71%) but showed much slower roll-off. At 100 and 1000 cd m−2, the non-doped PT-BZ-DMAC device still maintained acceptable efficiencies at 14.65% and 12.59%. In contrast, sulfone-modified PS-BZ-DMAC exhibited good efficiency of 20.55% only in doped OLED. The single crystal analysis and DFT calculation revealed that the phenyl thioether unit in PT-BZ-DMAC hardly contributes to the LUMO or the electronic transitions, instead determines the highly twisted geometry and acts as the barrier group, finally improving the performance of PT-BZ-DMAC in neat film device. Two TADF emitters are developed by attaching thioether or sulfone groups to the benzophenone acceptor. Unlike the strong electron withdrawing sulfone group that contributes to the electronic transition and TADF, the phenyl thioether blocked the conjugation of molecular backbone. The steric hindrance effect of phenyl thioether moiety along with the intermolecular hydrogen bondings can effectively prevents exciton quenching, thus further raising the EQE of non-doped TADF-OLED to 17.34% with low efficiency roll-off. [Display omitted] • Thioether and sulfone were incorporated as substituents to design TADF molecules PT-BZ-DMAC and PS-BZ-DMAC. • Thioether was found to strongly suppress intermolecular interactions and prevent exciton quenching via steric hindrance effect. • Non-doped OLED of thioether based PT-BZ-DMAC exhibited comparably high efficiency (17.34%) to its doped device (17.71%), but with much slower roll-off. • Sulfone based PS-BZ-DMAC exhibited high efficiency of 20.55% only in doped OLED, while non-doped device did not work. [ABSTRACT FROM AUTHOR]

Saturated red iridium phosphors are strongly desired for application in organic light-emitting diodes (OLEDs). Most of the reported iridium complexes with 2-arylquinoline or its derivatives as cyclometalating ligands are orange-red phosphorescent with peak wavelength below 620 nm. Herein trifluoromethyl (CF 3) or Fluorine (F) is introduced into the 6-site of quinoline ring to design and synthesize the cyclometalated ligands 2-phenyl-6-CF 3 /F-quinoline (CF 3 -phq or F-phq) and heteroleptic iridium complexes Ir(CF 3 -phq) 2 (acac) (Ir-1), Ir(CF 3 -phq) 2 (tmd) (Ir-2), Ir(F-phq) 2 (acac) (Ir-3) and Ir(F-phq) 2 (tmd) (Ir-4). Owing to the electron-deficient feature of CF 3 and F, the electron affinity of these complexes are increased, the corresponding LUMOs are pulled downwards, and the phosphorescence of CF 3 -containing iridium complexes are saturated red with peaks at 627–632 nm in photoluminescence. At the same time, by varying the ancillary ligand from acetylacetonate (acac) to 2,2,6,6-tetrametylheptane-3,5-dionate (tmd), the emitting performance are dramatically improved. As a result, the Ir(CF 3 -phq) 2 (tmd) based red OLED realized pure red electroluminescence with Commision Internationale de L'Eclairage (CIE) coordinates of (0.67, 0.33) with a high brightness of 12695 cd m−2 and a maximum external quantum efficiency of 14.96%, respectively, which maintained as high as 9.62% at a practical luminance of 1000 cd m−2. This is the first example of saturated red iridium phosphors with structure modification at the 6-site of quinoline ring of 2-phenylquinoline ligand. By incorporating electron-withdrawing fluorine (-F) or trifluoromethyl (-CF 3) at the 6-site of quinoline ring of the 2-phenyl-quiniline cyclometalating ligands and changing the auxiliary ligand from acac to bulky tmd, the heteroleptic iridium complexes realize pure red phosphorescence with CIE coordinates of (0.67, 0.33) and high efficiency of 14.96% in doped organic light-emitting diodes, which still remains at 9.62% at a practical brightness of 1000 cd m−2. Image 1 [ABSTRACT FROM AUTHOR]

In order to develop the high efficiency and cost-effective particle removal technology, a novel particle removal unit combined flue gas condensation and acoustic agglomeration was designed based on theoretical analysis. The performance of the designed combined particle removal unit was evaluated by the laboratory scale experiments. Compared with the single external field of sound or condensation, the combination of the two external fields made the removal efficiency higher. The maximum total removal efficiency could be up to 70% when the sound frequency was 1500 Hz, the sound pressure level (SPL) was 141 dB, and the cooling water flow rate was 560 L/h. With the increase of flue gas temperature drop, the removal efficiency increased. In addition, more waste water and heat could be recovered from the flue gas. There was an optimal sound frequency range of 1500–2000 Hz for the combined particle removal unit, and the removal efficiency decreased whether the sound frequency increased or decreased. The removal efficiency increased with the rise of SPL, but the considerable improvement was obtained only when the SPL exceeded 120 dB. Therefore, there was an SPL threshold for the application of combined particle removal unit. Through the techno-economic comparisons with other technologies, the novel particle removal unit was proved to be a highly efficient and cost-effective particle removal technology. • A novel combined particle removal unit was designed based on theoretical analysis. • The performance was evaluated by laboratory scale experiments. • Effects of parameters on particle removal efficiency were analyzed. • An optimal sound frequency range for particle removal was determined. • There was a SPL threshold for the application of combined particle removal unit. [ABSTRACT FROM AUTHOR]

This approach is developed to achieving smaller bandgap values and a closer bracketing of the CO 2 /reduced-H 2 O/oxidized redox couples to drive the overall conversion reactions of CO 2 and H 2 O, and this is critical for efficient solar energy conversion. Highlights • A new type of spinel germanium and iron double-substituted ZnGa 2 O 4 solid-solution photocatalysts was prepared. • The solid-solution catalysts showed improved photocatalytic activities for CO 2 reduction with H 2 O. • Introducing ZnFe 2 O 4 and Zn 2 GeO 4 into ZnGa 2 O 4 can effectively expand the light-harvesting wavelength range. • A great difference in the mobility between the electrons and holes to lessen the electron–hole recombination rate. • This approach can achieve smaller bandgap values and a closer bracketing of the CO 2 /reduced-H 2 O/oxidized redox couples. The conversion of CO 2 into renewable fuels by artificial photosynthesis is an attractive solution for storing solar energy in the form of chemical fuel. Herein, we presented a general molten-salt route to synthesize spinel germanium and iron double-substituted ZnGa 2 O 4 solid solutions. Introducing ZnFe 2 O 4 and Zn 2 GeO 4 into ZnGa 2 O 4 can effectively expand the light-harvesting wavelength range to improve the ability of photocatalyst in CO 2 reduction and H 2 O oxidation. The solid solutions provide a larger effective mass of holes compared with electrons through the introduction of Fe3d, Ge4s and Ge4p orbitals according to DFT analysis. This leads to a great difference in the mobility between the electrons and holes to lessen the electron–hole recombination rate, and enhance the conversion of CO 2 and H 2 O in kinetics. This approach is developed to achieving smaller bandgap values and a closer bracketing of the CO 2 /reduced-H 2 O/oxidized redox couples to drive the overall conversion of CO 2 and H 2 O. [ABSTRACT FROM AUTHOR]

It is well-known that there is an interaction between biomass and coal in co-gasification process. In this paper, gasification of semi-coke (SC) and soybean straw char (SS) and their blends were carried out using non-isothermal thermogravimetric method. Interaction between SS and SC during co-gasification was investigated and synergy factors were calculated at different conversion stage. In order to explore whether the physical and chemical structure features have an effect on interaction, surface area analyzer, XRF and Raman spectrometer were adopted to determine the porous properties, ordering degree and ash composition for blends. The results show that the changes of porous properties and ordering degree for blends follow a linear law. The correlation expressions linking char characteristics to char reactivities indicate that the degree of graphitization is the main reason influencing the gasification reactivity. The interaction exhibits a negative synergetic effect at low conversion stage and a positive synergetic effect at high conversion stage. In addition, there are significant synergistic effects in the co-gasification of 75%SC/25%SS. Similar conclusions about synergetic effect are also observed from the kinetics data calculated by three kinetic models. • The biochar reactivities significantly greater than that of semi-coke. • The reactivities of biochar and semi-coke correlate well with their properties. • The increasing proportion of biochar weakens synergies during co-gasification. • Synergies on gasification of char vary with biochar/semi-coke mass ratio. • SF < 1 at low conversion stage and SF ＞1 at high conversion stage for co-gasification. [ABSTRACT FROM AUTHOR]