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At partial load, traditional automotive gasoline engines have high pumping losses due to the throttling of the intake charge for load control. Variable Valve Timing (VVT) and the introduction of externally cooled EGR could reduce the pumping losses but only with a very limited effect. On the other hand, in the medium to full load range, the engine cannot utilize a high compression ratio due to limitations in knocking. A variable displacement, variable compression ratio device which utilizes an asymmetric camshaft to realize the different closure times of the two intake valves is discussed in this paper. The large-scale change in the intake valve timing leads to the large-scale change in the effective cylinder volume at the intake valve closure, which realizes a variable cylinder volume and a variable effective compression ratio. The device is utilized to reduce the pumping losses and to increase the in-cylinder thermal efficiency at the same time. Engine dyno test results indicate that, in the low to medium load range, a later closure of the intake valve could reduce the effective cylinder volume, and the intake pressure could be significantly increased, and therefore pumping losses reduced. However, the reduced effective cylinder volume due to a later intake valve closure would lead to reduction in the effective compression ratio (ECR) and a drop in in-cylinder thermal efficiency. Therefore, there is a balance point between the pumping loss reduction and the drop in in-cylinder thermal efficiency. On the other side, in the medium to full load range, when avoiding knocking becomes the major controlling factor of the combustion phasing (degree of constant-volume combustion) and the effective expansion ratio (EER), too high of an effective compression ratio would lead to significant drop in the effective expansion ratio EER and also the in-cylinder thermal efficiency. Therefore, there exists a best compromise between the ECR and EER, and the best system would be one with a moderate ECR but an EER as high as possible. The quantitative equations which include both ECR and EER in the thermal efficiency calculations captured the above observations pretty well and can be utilized to optimize for the best compromise of IVC, EVO, ECR, EER and engine performances during the concept stage and/or the calibration stage of an engine.

Developing highly efficient and stable non-precious metal catalysts for water splitting is urgently required. In this work, we report a facile one-step molten salt method for the preparation of self-supporting Ni-doped Mo2C on carbon fiber paper (Ni-Mo2CCB/CFP) for hydrogen evolution reaction (HER). The effects of nickel nitrate concentration on the phase composition, morphology, and electrocatalytic HER performance of Ni-doped Mo2C@CFP electrocatalysts was investigated. With the continuous increase of Ni(NO3)2 concentration, the morphology of Mo2C gradually changes from granular to flower-like, providing larger specific surface area and more active sites. Doping nickel (Ni) into the crystal lattice of Mo2C largely reduces the impedance of the electrocatalysts and enhances their electrocatalytic activity. The as-developed Mo2C-3 M Ni(NO3)2/CFP electrocatalyst exhibits high catalytic activity with a small overpotential of 56 mV at a current density of 10 mA·cm−2. This catalyst has a fast HER kinetics, as demonstrated by a very small Tafel slope of 27.4 mV·dec−1, and persistent long-term stability. A further higher Ni concentration had an adverse effect on the electrocatalytic performance. Density functional theory (DFT) calculations further verified the experimental results. Ni doping could reduce the binding energy of Mo-H, facilitating the desorption of the adsorbed hydrogen (Hads) on the surface, thereby improving the intrinsic catalytic activity of Ni-doped Mo2C-based catalysts. Nevertheless, excessive Ni doping would inhibit the catalytic activity of the electrocatalysts. This work not only provides a simple strategy for the facile preparation of non-precious metal electrocatalysts with high catalytic activity, but also unveils the influence mechanism of the Ni doping concentration on the HER performance of the electrocatalysts from the theoretical perspective.

ZrSiO4 demonstrates applicability as the SiC/SiC interphase. Via a non-hydrolyzed sol-gel method, the pyrolysis product, synthesis condition, and the formation effectiveness of the ZrSiO4 coating on SiC fibers were investigated. Mini-SiC/SiC composites with two layers of ZrSiO4 interface coatings were oxidized to preliminarily verify their oxidation resistance effect.

SiC/SiC composites are the ideal candidates for hot-end components in aerospace and other high-tech fields. In recent years, as one type of material with simple structures, mini-composites have been widely used to study or initially verify the properties of ceramic matrix composites (CMC). Nevertheless, attentions were rarely paid on the influence of strain rate on the mechanical properties of mini-composites. In this study, based on mini-SiC/SiC composites, we investigated the effect of the strain rate on their tensile strength, initial tensile modulus, Weibull modulus, and fracture work. Furthermore, the underlying mechanisms were discussed and the exact constitutive model of the as-prepared mini-SiC/SiC composites was constructed according to the Michaelis-Menten and generalized linear models. This work can fill the gaps in the CMC research in some degree and provide a preliminary theoretical basis for the formulation of tensile properties test standards of mini-composites.

Background Heterosis has been widely used for breeding high-yield crops, changes crop breeding and agricultural production by increasing yield. Transcriptome profiles of sorghum spikes in hybrid Jinnuo 3 and its parents 10480A and L17R were performed by RNA sequencing technology at secondary branch and spikelet differentiation period. Results During above two differentiation period, there were 2,641 and 2,175 differentially expressed genes (DEGs) between Jinnuo 3 and 10480A, respectively. Meanwhile, there were 1,387 and 1,094 DEGs between Jinnuo 3 and L17R, respectively. These indicated that massive DEGs were existed between hybird and its parents, and a more similar expression pattern was presented between hybrid and male parent. Gene expression inheritance analysis showed that most of genes were expressed additively, suggesting that the complementary effect may play a foundation role in sorghum spike heterosis. Among non-additive expression genes, L17R-dominant genes were predominant, indicating that male parent may provide beneficial alleles with great contribution to heterosis. GO and KEGG analysis suggested that metabolic pathways, such as photosynthetic antenna protein, photosynthesis, carbon fixation in photosynthetic organisms, amino acid metabolism, glycolysis, and endoplasmic reticulum protein processing, would participate in yield heterosis formation in hybrid Jinnuo 3. Further analysis showed that photosynthesis-related genes PsbW, PsbR, Lhca2, Lhcb1 and LAX3, spike structure development-related genes MADS1, MADS7, MADS16 and MADS55, as well as stress resistance-related genes WRKY14, WRKY35, HSFB2C and HSP70, might play an important role in yield heterosis formation in hybrid Jinnuo 3. Conclusion Hybrids Jinnuo 3 increased yield by simultaneously increasing source (photosynthetic efficiency-related genes), library (spike development-related genes), and resistance (inresistance-related genes). This molecular mechanism could provide new clues for sorghum heterosis utilization and high-yield breeding.

Ion-based memristive switching has attracted widespread attention from industries owing to its outstanding advantages in storage and neuromorphic computing. Major issues for achieving brain-inspired computation of highly functional memory in redox-based ion devices are relatively large variability in their operating parameters and limited cycling endurance. In some devices, volatile and nonvolatile operations often replace each other without changing operating conditions. To address these issues, it is important to observe directly what is happening in repeated operations. Herein, we use a planar device that enables direct capturing of microscopic behaviors in the nucleation and growth of metal whiskers under repeated switching to verify the microscopic origin of the large parameter variability. We report direct observations that reveal the physical origin for the large cycle-to-cycle and device-to-device variability in memristive switching, which was achieved using planar polymer atomic switches with a gap1 μm. We find that the deposition location of metal atoms is closely related to the crystallinity of the ion transport layer (solid polymer electrolyte, SPE). The filament variability (shape, position, quantity, etc.) during different cycles and devices is indeed the main reason for the observed variability in the operating characteristics. The results shed unique light on the complexity of the operation of the ion device, that is, the evolution of the dielectric layer and metal filament must be considered.

Iron carbide (Fe3C) has gained significant attention for use in energy storage applications. Furthermore, using a nano-scale metal as the catalyst can reduce the formation of a solid electrolyte interface (SEI), thus enhancing capacity. For these reasons, hierarchical Fe/Fe3C/C nanofibers are prepared by electrospinning with subsequent thermal treatment and used as the anodes for lithium ion batteries (LIBs). These anodes demonstrate a good rate and high capacities. At 0.1 A g−1, the Fe/Fe3C/C nanofiber electrode maintains 518 mA h g−1 after 100 cycles. When tested at 1 A g−1, the discharge capacity gradually increases and reaches 663 mA h g−1 after 1200 cycles. This work demonstrates the possibility to design and develop transition metal carbides (TMCs) for use in energy storage.

SiO2-based anodes for lithium ion batteries (LIBs) suffer from low conductivity and volume change in charge/discharge processes. It is reported that reasonable amorphous and nanometric characteristics can effectively improve the activity of SiO2 for Li+ storage. So, highly active SiO2@C nanofibers were prepared by electrospinning. Using X-ray diffraction (XRD), its amorphous characteristics were revealed. The results from scanning electron microscopy (SEM) and transmission electron microscopy (TEM) showed that it was a nanofiber structure. As an anode for LIBs, the SiO2@C nanofibrous electrode showed the discharge capacities of 675 and 188 mAh g−1 at 1 A g−1 (1000the cycle) and 10 A g−1 (5000th cycle), respectively. Even at 50 A g−1, it still maintained 88 mA h g−1 at 60,000 cycles, showing excellent stability and high rate.

Herein, a novel method for the gram-scale synthesis of (E)-quinoxalinone oximes through a multicomponent reaction under mild conditions is described. Such a transformation was performed under transition-metal-free conditions, affording (E)-oximes in a moderate-to-good yield through recrystallization. Our methodology demonstrates a successful combination of a Mannich-type reaction and radical coupling, providing a green and practical approach for the synthesis of potentially bioactive quinoxalinone-containing molecules.

Solid polymer electrolyte (SPE) is one of the choices for many ionic devices, including organic transistors, ion batteries, memristors, and more. However, uncontrollable conductive filament formation seriously affects the performance of the device. In this paper, the PEDOT:PSS was doped to improve the electronic and ionic conductivity of amorphous polymer electrolyte poly(vinylpyrrolidone) (PVP), realizing the transition of the filaments growth from cathode to anode in atomic switch memristors. Based on the difference in ion and electron mobility and scanning electron microscope observation, the in situ reductions of metal ions inside the dielectric layer can effectively prevent the formation of uncontrollable filaments. The formation of uniformly distributed metal particles in the dielectric layer is similar to co-sputter doping technology, which enables the device to exhibit excellent performance, such as smaller set/reset bias distribution, endurance, and retention. Obviously, this innovative way improves the conductive mechanism of ionic devices.

To improve densification degree and reduce process time, microwave sintering and heat molding method were combined to prepared SiC matrix reinforced SiC (SiC/SiC) composite via polymer infiltration and pyrolysis process (PIP). The effects of heat molding pressures on the densification process, flexural behaviors and failure modes of the fabricated SiC/SiC were examined via scanning electron microscopy (SEM), computed tomography (CT) technique and mercury intrusion test. Results indicate that heat molding process promoted the densification degrees of SiC/SiC and adjusted the interphase bonding between SiC matrix and SiC fibers on the basis of rapid microwave heating. Owing to the appropriate interphase bonding, SiC/SiC composites fabricated under the heat molding pressure of 3 MPa had preferable flexural properties and failure mode.

An interesting cascade reaction of N-(2-(4,5-dihydrooxazol-2-yl)phenyl)benzamide in the presence of an acid ion exchange resin is described. In this reaction, a range of substrates bearing various substituent groups are well compatible. This work provides a green and atom-economical alternative approach for the synthesis of quinazolin-4-ones in good yields.

BackgroundAt present, the molecular mechanisms underlying inflammation remain unclear. In recent years, research on inflammation has focused on stimulating cell inflammation by using external pathogens such as LPS or inflammatory factors. To investigate the molecular mechanism of inflammation from a new perspective, we designed a nucleic acid nanoflowers (NFs) complex to directly activate inflammatory genes to study the inflammatory response without the need for external microbial factors to trigger an inflammatory response. ResultsAn RNAa-type target gene-activated NF was designed. Human umbilical vein endothelial cells (HUVECs) were transfected with NFs carrying saRNAs to directly co-activate microRNA (miR)-155 and SHIP1 genes. Inflammatory gene and protein expression in the HUVECs were evaluated to assess whether miR-155 overexpression can trigger inflammation. After RNAa-type NFs were transferred into HUVECs, the expression of miR-155 and pro-inflammatory and cancer-related factors increased, anti-inflammatory factors were reduced, cell proliferation increased, and cell migration was promoted. IL-1β protein levels were decreased and SHIP1 expression was downregulated. When miR-155 and its target SHIP1 were both activated, the expression of both was unaltered, maintaining cell homeostasis. ConclusionMiR-155 and its target genes act as a molecular switch role in the development of inflammation.

SiCf/SiC composites using KD-I and KD-II SiC fibers braided preforms as the reinforcements were fabricated by applying the polymer impregnation and pyrolysis (PIP) technique with a microwave heating assistance. The microwave heating temperature was 1100 °C, 1200 °C, 1300 °C, and 1400 °C, respectively. Microstructures, flexure properties, and fracture behaviors of the composites were investigated. The KD II SiCf/SiC composites exhibited higher flexure properties and improved non-brittle fracture characteristics than those of the KD-I SiCf/SiC composites. The differences in the flexural properties, fracture behaviors and microstructures between the KD-I and KD II SiCf/SiC composites were discussed based on the tensile properties of the SiC filaments and the interfacial bonding statues in the composites.

To deeply study the variation mechanisms of mechanical properties, flexural modulus of SiC fibers reinforced SiC matrix (SiC/SiC) composites prepared by conventional and microwave heating at 800 °C–1100 °C was discussed in detail. The elastic modulus of fibers and matrix, interface bonding strength and porosity of SiC/SiC composites were considered together to analyze the changing tendencies and differences in their flexural modulus. The elastic modulus of fiber and matrix was determined by nanoindentation technique and interface characteristics applying fiber push-out test. The porosity and microstructure examinations were characterized by mercury intrusion method, X-ray Diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscope (TEM). Moreover, two conflicts between the changing trends of elastic modulus and chemical compositions of composite components were focused and explained. Results indicate that three factors played different roles in the flexural modulus of SiC/SiC composites and residual tensile stress in composite components led to the conflicts between their elastic modulus and chemical compositions.

Herein, a novel method for the gram-scale synthesis of (

Non-uniformity of switching parameters, e.g., switching voltage and resistances of the high resistance state and low resistance state, could obstruct the practical application of electrochemical metallization cells. Higher switching voltages are also undesirable in terms of power consumption. The non-uniformity is usually related to the number of conductive filaments (CFs) and their degree of dissolution during the RESET process. The number of CFs can be ideally reduced to one by decreasing the device area. However, the degree and location of the dissolution of CFs are difficult to control. Here, we introduce a SiO2/Ta2O5 heterojunction to control the dissolution of CFs, in which the growth direction and the shape of CFs are controlled by the SiO2 layer, while the dissolution of CFs is controlled in the ultrathin Ta2O5 layer. Transmission electron microscopy analysis clearly suggested that the formation/dissolution of CFs occurs in the ultrathin Ta2O5 layer, resulting in low voltage operation (0.3 V) with high stability and uniformity (Vset distributes in the range smaller than 0.1 V and Vreset distributes in the range smaller than 0.08 V).

The active oxidation of C/C composites at high temperature is a great obstacle for its application. In this study, a method of preparing SiC/Si–ZrB2–CrSi2/SiC multilayer oxidation-resistant coating for C/C composites by combining preoxidation and chemical vapor deposition (CVD) was proposed, and the results show that the coating has excellent oxidation resistance at 1473 K, 1573 K and 1673 K. Moreover, based on the uniform deformation model, the track of phases transition, lattice strain and internal stress for the protection/failure mechanisms at different temperatures/time were investigated by the agents of strain compatibility and stress distribution soured from XRD and Raman spectra.

SiC/SiC composites coated with the pyrolytic carbon (PyC) interphase coatings of different thickness were fabricated by polymer infiltration and pyrolysis (PIP) process using microwave sintering at 1100 °C assisted with the hot mould pressing pressure of 3 MPa. The effects of the PyC coating thickness on the densification, the flexural properties and microstructures of the fabricated SiC/SiC composites were investigated via the mercury intrusion test, the computed tomography (CT) technique and scanning electron microscopy (SEM). The results indicate that the preforms coated with thinner PyC coatings, which have better flexibility under the hot mould pressing process, bring SiC/SiC composites with higher densification degrees, due to their better flexibility under the hot press moulding process. Simultaneously, thicker PyC coatings result in weaker interphase debonding between SiC fibers and matrix quantified by the single fiber push-out test. Too thick or too thin PyC coatings both make against the flexural properties, as they will cause the debonding between SiC fibers and matrix too early or too late. The PyC coating thickness-0.20 μm is approximate for the better flexural properties.

The first example of oxidative C–H fluoroalkoxylation of quinoxalinones with fluoroalkyl alcohols under transition-metal and solvent-free conditions is described. This approach provides the synthesis of fluoroalkoxylated quinoxaline derivatives with good to excellent yields under mild reactions conditions. This method can also be extended to the facile and efficient synthesis of histamine-4 receptor.

Flowering time control is critically important for the reproductive accomplishment of higher plants as floral transition can be affected by both environmental and endogenous signals. Flowering Locus T-like (FTL) genes are major genetic determinants of flowering in plants. In rice, 13 OsFTL genes have been annotated in the genome and amongst them, Hd3a (OsFTL2) and RFT1 (OsFTL3) have been studied extensively and their functions are confirmed as central florigens that control rice flowering under short day and long day environment, respectively. In this report, a rice OsFTL gene, OsFTL10, was characterized, and its function on flowering and abiotic stress was investigated. The expression level of OsFTL10 was high in young seedlings and shown to be induced by GA3 and drought stress. Overexpression of OsFTL10 resulted in earlier flowering in rice plants by up to 2 weeks, through up-regulation of the downstream gene OsMADS15. OsFTL10 also regulated Ehd1 and OsMADS51 through a feedback mechanism. The OsFTL10 protein was also detected in both nucleus and cytoplasm. Furthermore, yeast two hybrid (Y2H) and bimolecular fluorescence complementation (BiFC) results show that OsFTL10 could interact with multiple 14-3-3s, suggesting that OsFTL10 might function in a similar way to Hd3a in promoting rice flowering by forming a FAC complex with 14-3-3, and OsFD1. Further experiments revealed that constitutive expression of OsFTL10 improved the drought tolerance of transgenic plants by stimulating the expression of drought responsive genes. These results suggest that rice FTL genes might function in flowering promotion and responses to environmental signals.

While lithium-ion batteries (LIBs) have been widely used in commercial devices, finding suitable anode materials for alkali metal batteries is still challenging. Therefore, Ni3S2/Ni@N-doped carbon composite electrode was fabricated as the anode for alkali metal batteries. It was found that the Ni3S2/Ni@N-doped carbon electrode achieved a capacity of 742 mAh g−1 at the 1500th cycle at the current density of 1000 mA g−1 for LIBs, and obtained 275 mAh g−1 at the 250th cycle during 500 mA g−1 for Na+ storage. Moreover, it showed 52 mAh g−1 after 50 cycles at 100 mA g−1 for K+ storage. The excellent performances of this electrode is likely due to the combined effect of Ni and C layer. This work provides a simple approach approach for the design of high-performance materials that can be applied to commercial production as a potential substitute for the current alkali ion battery anodes.

The authors describe a method for the fabrication of a nanohybrid composed of carbon dots (C-dots) and gold nanoparticles (AuNPs) by in-situ reduction of C-dots and hydroauric acid under alkaline conditions. The process does not require the presence of surfactant, stabilizing agent, or reducing agent. The hybrid material was deposited in a glassy carbon electrode (GCE), and the modified GCE exhibited good electrocatalytic activity toward the oxidation of nitrite due to the synergistic effects between carbon dots and AuNPs. The findings were used to develop an amperometric sensor for nitrite. The sensor shows a linear response in the concentration range from 0.1 μmol⋅L-1 to 2 mmol⋅L-1 and a low detection limit of 0.06 μmol⋅L-1 at the signal-to-noise ratio of 3.

SiC/SiC composites were fabricated by polymer impregnation and pyrolysis (PIP) process via microwave and conventional heating at 800 °C, 900 °C, 1000 °C and 1100 °C. The effects of sintering heating types and sintering temperatures on the densification process and pore distributions of the fabricated SiC/SiC composites were studied. The densification processes were discussed in the form of the weight gain rates at each PIP cycle. The pore location distributions were observed by scanning electron microscopy (SEM) and computed tomography (CT) technique. The porosity and pore size distributions were quantified by the mercury intrusion test. The results indicate that lower heating rates and higher sintering temperatures are benefit to the densification of the SiC/SiC composites. But the more micro-cracks generated from higher heating rates of microwave sintering (∼40 °C/min) make the flexural strength and toughness of the SiC/SiC composites higher than that of the conventional sintered ones.

In order to investigate the effect of microwave sintering time on the mechanical properties of SiC/SiC composites, four groups of SiC/SiC composites were fabricated via polymer impregnation and pyrolysis (PIP) process using microwave heating with different sintering time‐ 0.5 h, 1.0 h, 1.5 h and 2.0 h (at 1100 °C) at each PIP cycle. The flexural properties, the interfacial debonding strength between SiC fiber and matrix of the fabricated SiC/SiC composites and the SiC fiber filament strength after heat treatment were investigated. The results indicated that after heat treatment the residual strength of SiC fibers as reinforcement decreased and the interfacial debonding strength increased with the increase of the microwave sintering time at each PIP cycle, which together resulted in the changing tendency that the flexural strength and toughness of the as-fabricated SiC/SiC composites increased firstly and then decreased.

Previous studies have focused on the role of a cultured red macroalga Bangia fuscopurpurea as a functional food; however, except for antioxidant activity, there are no reports directly regarding the potential cosmetic properties of this alga. Our present study explored the moisturizing effect of its ethanol extract (BFH1) and used the tyrosinase activity inhibition assay to evaluate its in vitro whitening effect. The in vitro moisture-retention ability of BFH1 was similar to that of glycerol (positive control), but its moisture-absorption ability was significantly higher. The overall in vivo moisturizing effect of topical application of BFH1 in mice was similar to that of glycerol, but BFH1 did not cause significant changes in the oil content of the skin, and there were no obvious side effects regarding skin appearance and external behavior during treatment. BFH1 exerted in vitro tyrosinase inhibitory activity with a half-maximal inhibitory concentration (IC50) of 48.3 μg/mL (IC50 of positive control, vitamin C: 19.6 μg/mL). The total phenolic content of BFH1 was determined as 10.8 % ± 0.07 %. Thus, BFH1 has high potential to be turned into a cosmetic ingredient with moisturizing and whitening effects.