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• Considering the effects of frequency coupling and cascade transformer, this paper establishes the frequency coupling impedance model of GCWPS and applies the generalized Nyquist criterion to analyze the stability of the whole system as the grid strength, PLL bandwidth and output power change. • Aiming at the power oscillation problem of GCWPS under weak grid, a composite feedforward damping oscillation suppression strategy is proposed, and the output impedance characteristic of GCWPS is reconstructed. • The frequency coupling impedance model of GCWPS adopting the oscillation suppression strategy proposed in this paper is constructed, and a comparison between its stability and that of the GCWPS adopting the traditional control strategy is made. It is proved that the system has stronger adaptability to the increase of output power and PLL bandwidth under weak grid when adopting the proposed oscillation suppression strategy. The stability of grid-connected wind power system (GCWPS) is prone to deteriorate due to the impedance interaction between wind turbines and the weak grid. For purpose of finding out the cause of power oscillation and effectively improving the stability of GCWPS under weak grid, firstly of all, a frequency coupling impedance model (FCIM) for GCWPS is established. Through analyzing the impedance characteristic of GCWPS, a significant coupling effect between GCWPS impedance and grid impedance in the middle-low frequency region under weak grid is observed, which is easy to cause power oscillation. For purpose of restraining the power oscillation of GCWPS under weak grid, this paper proposes an oscillation suppression strategy based on composite feedforward damping. Virtual damping is incorporated into the feedforward loop to rectify the impedance characteristic curve of GCWPS. Then, a FCIM of GCWPS that adopts the proposed oscillation suppression strategy is established, and the stability analysis demonstrates that the proposed strategy effectively enhances the GCWPS stability under weak grid. Additionally, compared with conventional control strategy, GCWPS exhibits enhanced adaptability to the increased output power and phase-locked loop (PLL) bandwidth under weak grid. Finally, experiments are undertaken to evidence the feasibility of the proposed oscillation suppression strategy. [ABSTRACT FROM AUTHOR]

Understanding urban dynamics requires comprehensive building analysis, yet current methods focusing on specific aspects hinder the production of unified and large-scale inventories. This study introduces a multi-task deep learning network with a flexible architecture for simultaneously extracting spatial and attributional building information from high-resolution satellite images. This method efficiently segments rooftops and classifies buildings by urban function and architectural style of rooftops. Moreover, a strategic spatial sampling scheme from a data-centric perspective, informed by geographic and environmental diversity, optimizes the selection of representative samples to improve training efficiency and predictive accuracy. Comparative analyses demonstrate the framework's superior performance, achieving an F1 score of 84.30% and an intersection over union of 72.86% in rooftop segmentation, and Kappa scores of 74.67% and 70.04% in classifying urban functions and architectural types, outperforming other advanced models by 2% to 25% across various metrics. Additionally, the adaptability of the network ensures that the framework meets diverse accuracy and efficiency requirements. By applying the proposed methodology to Shanghai, a unified city-scale dataset is generated. This dataset underscores the practical applicability and potential influence of the proposed methods in the fields of urban studies and sustainable development. • A multi-task network extracting diverse building details from high-resolution satellite images is proposed. • Spatial sampling from a data centric perspective for representative sample selection is designed. • Large-scale applications prove generalization, and building-related datasets are released. [ABSTRACT FROM AUTHOR]

In the construction of roadbeds in mountainous areas, crushed rock slag (CRS) generated by tunnel blasting is usually reused as road construction material to reduce environmental pollution and construction costs. A series of large-scale drained triaxial tests were conducted to investigate the mechanical behavior of CRS subjected to static and traffic loading. The static triaxial tests determined the maximum stress level that can be applied to the cyclic test. The cyclic triaxial test analyses the influence of cyclic stress amplitude and confining pressure on the cumulative strain of CRS material. The particle breakage of the sample under various conditions after cyclic loading was discussed, and the relationship between the relative breakage index and the final accumulated strain was analyzed. Test results indicated that with the increase in confining pressure, the peak strength of the material exhibits a continual enhancement, while the expansion behavior experiences a gradual attenuation. In the range of static failure strength, the increase of cyclic stress level will significantly increase the accumulated axial strain rate. After the cyclic loading, the particle breakage patterns are similar under different confining pressures. A good power function relationship exists between the relative breakage index and final axial strain, and further derivation of the functional expression of the relative breakage index and both cyclic stress ratio and confining pressure. • It is confirmed that the tunnel slag material is a strain softening type material, and the degree of softening decreases as the confining pressure increases. • Under cyclic loading, the accumulated strain of CRS material is influenced by cyclic stress and confining pressure, and the final strain shows exponential growth with the both factors. • Under cyclic loading, the main forms of breakage of CRS are grinding and surface crushing. The degree of breakage increases with the increase of confining pressure and cyclic stress ratio. • The relative breakage index shows a good linear relationship with the cyclic stress ratio. A model was established to represent the relative breakage index using confining pressure and cyclic stress ratio. [ABSTRACT FROM AUTHOR]

Summary Selective block of Na V 1.7 promises to produce non-narcotic analgesic activity without motor or cognitive impairment. Several Na V 1.7-selective blockers have been reported, but efficacy in animal pain models required high multiples of the IC 50 for channel block. Here, we report a target engagement assay using transgenic mice that has enabled the development of a second generation of selective Nav1.7 inhibitors that show robust analgesic activity in inflammatory and neuropathic pain models at low multiples of the IC 50. Like earlier arylsulfonamides, these newer acylsulfonamides target a binding site on the surface of voltage sensor domain 4 to achieve high selectivity among sodium channel isoforms and steeply state-dependent block. The improved efficacy correlates with very slow dissociation from the target channel. Chronic dosing increases compound potency about 10-fold, possibly due to reversal of sensitization arising during chronic injury, and provides efficacy that persists long after the compound has cleared from plasma. Graphical Abstract Highlights • Aconitine-induced pain in IEM mice enables assay for target engagement of hNa V 1.7 • Acylsulfonamides inhibit pain at low multiples of the IC 50 for inhibition of Na V 1.7 • Improvement versus arylsulfonamides correlates with longer residency time on Na V 1.7 • Repeat dosing of acylsulfonamides results in a 10-fold decrease in EC 50 for analgesia Bankar et al. show that acylsulfonamides produce analgesic activity at low multiples of the IC 50 for inhibition of Na V 1.7, in contrast to studies with arylsulfonamides that required >10 times the IC 50. The improvement correlates with longer residency time on the target channels. [ABSTRACT FROM AUTHOR]

Novel citric acid based photoluminescent dyes and biodegradable polymers are synthesized via a facile “one-pot” reaction. A comprehensive understanding of the fluorescence mechanisms of the resulting citric acid-based fluorophores is reported. Two distinct types of fluorophores are identified: a thiozolopyridine family with high quantum yield, long lifetime, and exceptional photostability, and a dioxopyridine family with relatively lower quantum yield, multiple lifetimes, and solvent-dependent band shifting behavior. Applications in molecular labeling and cell imaging were demonstrated. The above discoveries contribute to the field of fluorescence chemistry and have laid a solid foundation for further development of new fluorophores and materials that show promise in a diversity of fluorescence-based applications. Statement of Significance Photoluminescent materials are pivotal for fluorescence based imaging, labeling and sensing applications. Understanding their fluorescence mechanism is challenging and imperative. We develop a new class of citric acid-derived fluorescent materials in forms of polymers and small molecular dyes by a one-step solvent free reaction. We discovered two different classes of citric acid-derived fluorophores. A two-ring thiozolopyridine structure demonstrates strong fluorescence and exceptional resistance to photo-bleaching. A one-ring dioxopyridine exhibits relative weak fluorescence but with intriguing excitation and solvent-dependent emission wavelength shifting. Our methodology of synthesizing citric acid-derived fluorophores and the understanding on their luminescence are instrumental to the design and production of a large number of new photoluminescent materials for biological and biomedical applications. [ABSTRACT FROM AUTHOR]

Fluorescent biomaterials have attracted significant research efforts in the past decades. Herein, we report a new series of biodegradable, fluorescence imaging-enabled copolymers, biodegradable photoluminescent poly(lactide-co-glycolide) (BPLP-co-PLGA). Photoluminescence characterization shows that BPLP-co-PLGA solutions, films and nanoparticles all exhibit strong, tunable and stable photoluminescence. By adjusting the molar ratios of l -lactide (LA)/glycolide (GA) and (LA + GA)/BPLP, full degradation of BPLP-co-PLGA can be achieved in 8–16 weeks. The fluorescence decay behavior of BPLP-co-PLGA can be used for non-invasive monitoring of material degradation. In vitro cytotoxicity and in vivo foreign body response evaluations demonstrate that BPLP-co-PLGA exhibits similar biocompatibility to poly(lactide-co-glycolide) (PLGA). The imaging-enabled BPLP-co-PLGA was fabricated into porous scaffolds whose degradation can be monitored through non-invasive imaging and nanoparticles that show theranostic potential demonstrated by fluorescent cellular labeling, imaging and sustained 5-fluorouracil delivery. The development of inherently fluorescent PLGA copolymers is expected to impact the use of already widely accepted PLGA polymers for applications where fluorescent properties are highly desired but limited by the conventional use of cytotoxic quantum dots and photobleaching organic dyes. Statement of significance This manuscript describes a novel strategy of conferring intrinsic photoluminescence to the widely used biodegradable polymers, poly(lactide-co-glycolide) without introducing any cytotoxic quantum dots or photo-bleaching organic dyes, which may greatly expand the applications of these polymers in where fluorescent properties are highly desired. Given the already significant impact generated by the use of PLGA and alike, this work contributes to fluorescence chemistry and new functional biomaterial design and will potentially generate significant impact on many fields of applications such as tissue engineering, molecular imaging and labeling, and drug delivery. [ABSTRACT FROM AUTHOR]

Abstract: The objective of this research is to develop a dual growth factor-releasing nanoparticle-in-nanofiber system for wound healing applications. In order to mimic and promote the natural healing procedure, chitosan and poly(ethylene oxide) were electrospun into nanofibrous meshes as mimics of extracellular matrix. Vascular endothelial growth factor (VEGF) was loaded within nanofibers to promote angiogenesis in the short term. In addition, platelet-derived growth factor-BB (PDGF-BB) encapsulated poly(lactic-co-glycolic acid) nanoparticles were embedded inside nanofibers to generate a sustained release of PDGF-BB for accelerated tissue regeneration and remodeling. In vitro studies revealed that our nanofibrous composites delivered VEGF quickly and PDGF-BB in a relayed manner, supported fibroblast growth and exhibited anti-bacterial activities. A preliminary in vivo study performed on normal full thickness rat skin wound models demonstrated that nanofiber/nanoparticle scaffolds significantly accelerated the wound healing process by promoting angiogenesis, increasing re-epithelialization and controlling granulation tissue formation. For later stages of healing, evidence also showed quicker collagen deposition and earlier remodeling of the injured site to achieve a faster full regeneration of skin compared to the commercial Hydrofera Blue® wound dressing. These results suggest that our nanoparticle-in-nanofiber system could provide a promising treatment for normal and chronic wound healing. [Copyright &y& Elsevier]

Engaging children in describing real-life scenes provides an effective approach to fostering language production and developing their language skills, enabling them to establish meaningful connections between their language proficiency and authentic contexts. However, for such learning tasks, there has been a lack of research focusing on promoting self-directed language learning by using artificial intelligence techniques, primarily due to the challenges of handling multimodal information involved in such tasks. To address this gap, this study introduced a two-stage automated evaluation method that employed emerging cross-modal matching AI techniques. Firstly, an automated scoring model was developed to evaluate the quality of students' responses to scene description tasks. Compared with manually assigned human scores, our model scored students' descriptions accurately, as evidenced by a small testing mean absolute error of 0.3969 for a total score of 10 points. Based on the scoring results, immediate feedback was then provided to students by generating targeted comments and suggestions. The goal of this feedback was to assist students in progressively improving their descriptions of daily-life scenes, thereby enabling them to practice their language skills independently. To assess the effectiveness of the feedback, a comprehensive investigation was conducted involving 157 students from middle schools in China, and both qualitative and quantitative experimental data were collected from the students. It is found that the quality of students' descriptions was improved significantly with the assistance of immediate feedback. On average, students achieved an increase of 1.48 points in their scores after making revisions based on the feedback. In addition, students reported positive learning experiences and expressed favorable opinions regarding the language learning tasks with the automated evaluation. The findings of this study have significant implications for future research and educational practice. They not only highlighted the potential of emerging cross-modal matching AI techniques in automatically evaluating learning tasks involving multimodal data but also suggested that providing immediate targeted feedback based on automated scoring results can effectively promote students' self-directed language learning. • Generating descriptions from real-life visuals enhances authentic language learning. • Feasible to provide automated feedback in self-directed language learning using AI. • Automated feedback motivates students to improve and engage in language learning. [ABSTRACT FROM AUTHOR]

• A small-signal sequence impedance model of the island power system is built by harmonic linearization method. It is found that the output sequence impedance of the source PWM inverter in the system is not affected by the stable operating point. • Based on the impedance model, the influence of load type and load power on the stability of the island power system is analyzed. The essential reason of the high-frequency oscillation is that the capacitive output impedance of the source PWM inverter does not match the inductive output impedance of the load PWM rectifier at high-frequency areas. • An impedance reconstruction control for the source PWM inverter is proposed, which improves the phase of the output sequence impedance of the source PWM inverter at high-frequency areas to effectively suppress the high-frequency oscillation of the island power system. In island power system with strong mutual interaction of power electronic devices, stability problems such as high-frequency oscillation are prone to occur. Firstly, a small-signal sequence impedance model of an island power system is built by harmonic linearization method. It is found that the output sequence impedance of the source PWM inverter in the system is not affected by the stable operating point, but the input sequence impedance of the load PWM rectifier will decrease with the increase of power. Then, based on the sequence impedance model and Nyquist stability criterion, the influence of load type and load power on stability of the island power system is analyzed, which can reveal that high-frequency oscillation occurs when the source PWM inverter interacts with the load PWM rectifier. The essential reason of the high-frequency oscillation is that the capacitive output impedance of the source PWM inverter does not match the inductive output impedance of the load PWM rectifier at high-frequency areas. Aiming at this issue, an impedance reconstruction control for the source PWM inverter is proposed, which improves the phase of the output sequence impedance of the source PWM inverter at high-frequency areas to effectively suppress the high-frequency oscillation of the system. Finally, experiment results verify the correctness of analysis and effectiveness of the proposed control strategy. [ABSTRACT FROM AUTHOR]

• A small-signal model of the grid-connected system of SSVSI is established. The model fully considers the power coupling phenomenon in the system and provides a basis for in-depth analysis of the system characteristics. • The effects of grid equivalent resistance and SSVSI control parameters on the system are comprehensively analyzed. The effects of power coupling on the stable region of control parameters are quantitatively analyzed. In addition, the contradiction between SFR suppression and power coupling is analyzed when the virtual resistance is introduced. • An SFR suppression method based on band-stop filters is proposed. The proposed method effectively suppresses the resonance peaks without changing the original control parameters of the system, and improves the power response speed of the system. In addition, the proposed method avoids exacerbating the power coupling of the system compared to the virtual resistance method. Self-synchronizing voltage source inverter (SSVSI) can effectively improve grid frequency stability. However, the synchronous frequency resonance (SFR) inevitably exists in SSVSI. In this paper, a small-signal model considering power coupling is established to analyze the system characteristics. It is found that the control parameter adjustment and the virtual resistance method can suppress the SFR. However, the control parameter adjustment will change the dynamic and steady-state characteristics of the system, and the virtual resistance method will exacerbate the power coupling of the system. For this reason, based on the idea of eliminating the resonance peaks, this paper proposes an SFR suppression method based on band-stop filters. By connecting band-stop filters in series in the active power control loop (APCL) and the reactive power control loop (RPCL), the proposed method effectively suppresses the resonance peaks without changing the original control parameters of the system, and the control bandwidth is wider, which improves the power response speed of the system. In addition, the proposed method avoids exacerbating the power coupling of the system compared with the virtual resistance method. Finally, the simulation and experimental results verify the correctness of the theoretical analysis and the effectiveness of the control method. [ABSTRACT FROM AUTHOR]

• The effect of the internal power-sharing ratio of WTGs on the admittance characteristics of wind farms is investigated. • The identification method of the AOP-admittance model considering frequency-coupling for wind farms is proposed. • This method can identify the AOP-admittance model of wind farms by measurement data of WTGs under several operating points. • The identification method can avoid the dimension disaster in admittance modeling for the wind farm. Admittance identification is an effective tool to solve the issue of black-box admittance modeling in wind farms. However, due to the large operating range of wind farms, it is difficult to accurately identify the admittance model of wind farms under all operating conditions, which limits the research on wideband oscillation caused by the interaction between wind farms and the power grid. This paper analyses the characteristics of the frequency-coupling admittance for wind farms. It is found that the power-sharing ratio of wind turbine generators (WTGs) affects the admittance characteristic of the wind farm, which leads to a huge number of operating points for the wind farm. The all-operating-point (AOP) admittance model of wind farms considering frequency-coupling characteristics is hard to directly identify. Aiming for this problem, this paper proposes to first identify the AOP-admittance model for WTGs. Then, based on the operating points of each WTG and the network structure, the AOP-admittance model of the wind farm is obtained via the admittance aggregation and model reduction method. This proposed method solves the problem of black-box admittance modeling and addresses the problem of dimension disaster in admittance modeling for wind farms. The identified model of the wind farm can be used to accurately assess the stability of the wind power integration system under various operating conditions. Finally, the effectiveness of the proposed method is verified through the admittance measurement and stability analysis of the wind farm. [ABSTRACT FROM AUTHOR]

Imaging optics play a crucial role in the angle measurement system. However, the field of view (FOV) is inversely proportional to the focal length in the optical imaging system, meaning that the detection distance and FOV cannot be considered simultaneously. This paper presents a non-imaging angle detection system incorporating an optical model using a compound paraboloid collector (CPC) and data processing based on a backpropagation (BP) neural network. This method has a detection capability of 200 km, with the FOV of azimuth and pitch angles being 60°. The angle detection resolution is 1°, while the angle error is less than 0.1°. A detector array absorbs the far-field light reflected by the CPC. Changing the pitch and azimuth angles establishes the nonlinear relationship between the number of rays each detector receives and the angle. Then, a BP neural network is used to train the nonlinear relationship into a linear one. Based on the light flux data on the detector array, the simulation results show that the system can effectively predict the angle. [ABSTRACT FROM AUTHOR]

Offshore wind turbines are subjected to significant combination environmental loads from wind and wave action. Under such conditions, the directions of these environmental loads vary over the structure's service life, and the stress directions of subsoil rotates during the wind turbine operating process. Tests were conducted on saturated soft clay using multi-directional cyclic simple apparatus to investigate the influence of stress rotation angle. All test results implied that both the stress rotation angles and cyclic stress ratios influence the dynamic responses of the reconstituted clay greatly and regularly: shear strain and pore pressure decrease as θ values vary from 0° to 90° and increase as θ changes between 120° and 180°. Shear strain accumulative ratio for θ = 0°, 30°, 150°, and 180° is more incredible than that of 60°, 120°, and 90°. Increasing the cyclic shear stress ratio will enhance the effect of θ on the cyclic strain and excess pore water pressure. • Shear paths varies lead bidirectional shear stress fluctuate range changed with stress rotate angle. The x -directional stress fluctuate range is about two times of that y -direction. And the stress fluctuate of x direction is also varied with θ. • The shear strain and excess pore pressure decrease as θ increases from 0° to 90° and increase as θ increases from 90° to 180°, which is related to the shear stress fluctuate range. • All γd – N and u – N curves depend on the cyclic stress ratio and the principal stress rotation angles and the effect of the principal stress rotation angle on the strain and excess pore pressure will be enhanced as the increasing CSR s. [ABSTRACT FROM AUTHOR]

In consideration of skyrocketing price in pavement materials and ever-increasing attention to environment preservation, the utilization of reclaimed asphalt pavement (RAP) into asphalt mixtures has gained more and more favor. However, the uniformity of virgin and RAP aggregate in recycled asphalt mixtures (RAM) has not yet been studied due to the difficulty in informational extraction of multi-structures. To address this, white dolomite was used as virgin aggregate to be distinguished from RAP aggregate based on their color difference. The shear gyratory compactor specimens of RAM were prepared and saw-cut, and then meso-structures including virgin aggregate, RAP aggregate and asphalt mortar were extracted using digital image processing (DIP) technology. The DIP processes mainly involved retention of blue channel for image graying, newly proposed double-threshold OTSU method for image segmentation and image morphology processing. The aggregate uniformity index (AUI) was proposed based on the coefficient of variation of aggregate area ratio. The influences of RAP that were pre-processed by refined decomposition (RD) and routine crushing (RC) and its content on the aggregate uniformity were evaluated. The results demonstrate the efficacy of the improved DIP approach, as evidenced by the maximum mean absolute error between laboratory-measured and image-estimated gradation that is lower than 7.8 %. The addition of RAP into asphalt mixtures is adverse to the aggregate uniformity. The higher the RAP content, the inferior the aggregate uniformity of RAM, which attributes to the agglomeration of RAP materials. RAP agglomeration leads to the heterogeneity of RAP aggregate and thus dominates the heterogeneity of the whole aggregate. Therefore, the aggregate uniformity of RAM produced by RD-RAP is superior to that produced by RC-RAP. The superior degree is 9 %. • Dolomite is used as virgin aggregate to distinguish from RAP aggregate. • Double-threshold OTSU method for image segmentation in the recycled asphalt mixtures is proposed. • RAP has adverse effect on the aggregate uniformity due to its agglomeration. • Recycled asphalt mixtures with refined decomposed RAP show superior aggregate uniformity than routine crushed RAP. [ABSTRACT FROM AUTHOR]

Air booster vacuum preloading is a newly improved method applied in land reclamation projects. Highly pressurized air can provide an additional pressure difference between the prefabricated vertical drain (PVD) and injection point, thereby increasing the hydraulic gradient and generating small fractures that can improve the soil permeability and the transmission efficiency of the vacuum pressure. However, with a premature activation time, the pressurized air can create air channels connected to the PVD, which may drastically decrease the vacuum pressure. With a delayed activation time, the strength of the dredged clay may be too high to permit fractures, thus limiting the permeability improvement. In this study, soils with degrees of consolidation (DOCs) of 0%, 40%, 60%, and 80% were selected for testing the efficacy of initial booster activation times in four tests. The results show that the pressurizing groups were more effective in improving the consolidation of soils, and the best effect of the use of air booster is obtained when soil has been consolidated to a DOC of 60%. The lower soils of the pressurized groups showed greater increase rates than those demonstrated by conventional vacuum preloading. [ABSTRACT FROM AUTHOR]

Abstract In this study, Cu 2 ZnSnS 4 (CZTS) thin films were fabricated by periodically sequential depositions of metallic precursors by magnetron sputtering followed by sulfurization. The element compositions, crystal structures, and surface morphologies of the single-period precursor (Zn/Sn/Cu) and four-period precursor (Zn/Sn/Cu/Zn/Sn/Cu/Zn/Sn/Cu/Zn/Sn/Cu) during the sulfurization process were investigated. The experimental results showed that in the initial stage of sulfurization, the single-period precursor had a more efficient reaction with sulfur vapor below 300 °C because of its thicker metal layers. During the process of sulfurization, the CZTS phase first formed in the four-period film at 400 °C, owing to the wide distribution of the internal layer in the periodic thin film. With a further increase in temperature, the crystallinity of CZTS was enhanced and the secondary phases were reduced. A CZTS phase with Cu-poor and Zn-rich composition was confirmed in both thin films after complete sulfurization. The CZTS thin film with a four-period precursor showed a better degree of crystallization, and a single phase of CZTS was obtained more easily than in the single-period thin film. Therefore, using a periodic structure can promote the sulfurization reaction of Cu-Zn-Sn precursors and enhance the properties of CZTS thin films. [ABSTRACT FROM AUTHOR]

Dependence on the crystallization behavior, thermal ability and soft magnetic properties of the Fe 84.7 Si x B 10.5-x P 4 Cu 0.5 C 0.3 (x = 0–2.0 at.%) alloys with high Fe content were investigated. The results show that the addition of minor Si significantly weakens the crystallization peaks and increases the amorphous forming ability of the alloys. With the increase of Si content, it improves the second crystallization peak temperature and greatly enlarges the temperature interval between the two crystallization peaks, which broadens the annealing range. When Si content is up to 1.5 at.%, the alloy can effectively inhibit the precipitation of Fe-B compounds during the process of annealing. The addition of Si contributes to the formation of stable nano-structure, leading to a good soft magnetic properties for the amorphous alloy. Through the optimum annealing treatments, the nanocrystalline alloy exhibits the high Ms of 206.5 emu/g (Bs ≈ 1.92 T) and low Hc of 12.5 A/m. [ABSTRACT FROM AUTHOR]

• True triaxial unloading tests were performed on sandstone with various moisture contents. • Slabbing is more prone to occur in higher moisture conditions for a constant σ 2 level. • Moisture contents and σ 2 may affect the failure intensity and fragmentation degree of sandstone. • The cracking mode was evaluated via AE features and microscopic morphological characteristics. • The cracking mechanism of immersed sandstone was revealed under true triaxial unloading condition. The presence of water has been confirmed to play an important role in affecting the failure properties of underground surrounding rock when subjected to complicated stress circumstances. In the current study, the crack propagation behavior of red sandstone affected by various moisture contents and intermediate principal stresses were investigated by using the QKX-YB200 true triaxial test system with unloading minimum principal stress. The experimental results demonstrate that the failure mode can be divided into shear, tension with shear, and slabbing. A clear observation of the fractured specimen shows that the extensional cracks tend to increase while shear cracks gradually diminish with the increase of moisture content and intermediate principal stress. For natural sandstone (with lower moisture content), the transition of failure mode from shear to slabbing requires higher intermediate principal stress. However, with the increase of moisture content, the occurrence of slabbing failure requires lower intermediate principal stress. The analysis of failure process indicates that the presence of water may restrain the possibility of rockburst, and the intermediate principal stress exhibits distinct functions in the failure behavior of natural and saturated sandstone. The surface microscopic morphological characteristics and acoustic emission signal feature were also analyzed to validate the transformation of the cracking mode. The current research indicated that the water-induced micro defect and damage effect, "water wedge" effect, intermediate principal stress effect are the key factors that contribute to the final slabbing failure in immersed hard rocks under true‑triaxial unloading conditions. [ABSTRACT FROM AUTHOR]

The single-crystalline silicon substrate has close lattice constant with Cu 2 ZnSnS 4 (CZTS), which is beneficial to the crystalline growth of CZTS thin films. In this work, the CZTS thin films were deposited on silicon substrates by sputtering and post-sulfurization to form CZTS/Si heterojunctions. The experimental results indicate the formation of CZTS with preferred orientation of (1 1 2) plane. The crystallinity of CZTS enhances and the secondary phases reduce with increasing sulfurization temperature. The fabricated CZTS/Si heterojunctions show rectifying and photovoltaic properties. The photovoltaic properties of CZTS/Si heterojunctions are further analyzed by the absorption of incident photons in the CZTS thin films and silicon substrates. [ABSTRACT FROM AUTHOR]

Abstract: We have synthesized multi-wall carbon nanotubes by catalytic chemical vapour deposition (CCVD) method using an AB5 hydrogen storage alloy with diameter ranging from 38 to 150μm as a catalyst. The H2 uptake capacity of the carbon nanotubes prepared using an AB5 alloy as a catalyst is about 4wt.% through to the pressure of 8MPa at room temperature. Differential thermal analysis–thermogravimetric analysis (DTA–TGA) technique has been applied to investigate the effect of the diameters of the AB5 alloy catalyst of micrometer magnitude and the technique conditions in the CCVD process on the thermal properties of carbon nanotubes. As the catalyst diameter increases from 38 to 150μm, the average diameter of the prepared carbon nanotubes increases and the diameter distribution also enlarges. Electron microscope, Raman spectrum and thermal analysis all indicated that the catalyst sizes affect the diameter and the thermal properties of the carbon nanotubes. When the catalyst diameter increases, the initial weight loss temperature and the differential thermal peak temperature of the carbon nanotubes increases, which shows that the lager the diameter of the carbon nanotubes is, the higher the oxidation temperature, and the better the anti-oxidizablity. However, if the diameter of the catalyst is larger than 100μm, the anti-oxidizablity does not rise anymore but tend to be invariableness. In the CCVD preparation process, the anti-oxidizability of the carbon nanotubes increases, when raising the ratio of the hydrogen gas in the reaction gas in our experimental range (4:1, 3:1, and 2:1, respectively). [Copyright &y& Elsevier]

[Display omitted] • A series of novel aryl sulfonamide Na V 1.5 inhibitors were described. • Compound (-)-6 is a potent Na V 1.5 inhibitor with high selectivity over hERG and other cardiac ion channels. • Compound (-)-6 is effective in shortening prolonged APDs induced by ATX-II in human iPSC-CMs. • These potent Na V 1.5 inhibitors bind to the local anesthetic binding site in the pore domain. • An efficient method for preparation of trans -3-arylpiperidin-4-ols was developed. We describe the synthesis and biological evaluation of a series of novel aryl sulfonamides that exhibit potent inhibition of Na V 1.5. Unlike local anesthetics that are currently used for treatment of Long QT Syndrome 3 (LQT-3), the most potent compound (-)- 6 in this series shows high selectivity over hERG and other cardiac ion channels and has a low brain to plasma ratio to minimize CNS side effects. Compound (-)- 6 is also effective in shortening prolonged action potential durations (APDs) in a pharmacological model of LQT-3 syndrome in pluripotent stem cell-derived cardiomyocytes (iPSC-CMs). Unlike most aryl sulfonamide Na V inhibitors that bind to the channel voltage sensors, these Na V 1.5 inhibitors bind to the local anesthetic binding site in the central pore of the channel. [ABSTRACT FROM AUTHOR]

Improve the Finemet alloy properties by adding Ni elements, and through change the Ni content to control the composition of the alloy system, the alloy has resistance to DC bias characteristics and excellent soft magnetic properties. In the Fe 79.5-X Si 6 B 12 Cu 1 Nb 1.5 Ni X (X = 0, 1, 3, 5, 7, 10) alloy, increasing the content of Ni improves the amorphous forming ability of the alloy, and increased thermal stability, the soft magnetic performance has also been improved. with X is about 10 at.% the nanocrystalline core of alloy ribbon annealed show μ is about 3.4 k, and Hc is about 17.51 A/m. The addition of Ni is beneficial to improve the linearity of the hysteresis loop, when the amount of Ni content increases, the linearity is significantly improved, Ni10at.% alloy shows good DC bias resistance in the magnetic field. And tensile stress has also been improved linearity of the hysteresis loop, make the alloy shows good DC bias resistance in the magnetic field of 0–600 A/m. So it has constant magnetic permeability in this magnetic field, the alloys to be a kind of promising material for current transformer with direct current tolerance. ● When the Ni content is between 0at% and 10at%, increasing the content Ni improves the amorphous forming ability of the alloy. ● Increasing the content Ni improve the hysteresis loop linearity of the alloy. ● Tensile stress are beneficial to improve the DC bias resistance of the alloy. [ABSTRACT FROM AUTHOR]

Low-carbon design is a sustainable method, which coordinates the carbon footprint, cost and performance of each stage in product lifecycle from the design source to satisfying low-carbon demand. It is also a significant technology to reduce the carbon emission before manufacturing. To effectively and efficiently reduce the carbon emission, a low carbon-oriented design method is studied in product lifecycle. A product is modularized to function units for obtaining carbon footprint, which are quantified based on the framework of PAS2050. In order to identify the high-emission parts, an activity-based method is used to allocate the carbon footprint. Through the lifecycle analysis, the major parts and components characterized with high carbon emission are picked out according to allocation result. Due to the close relationship and conflict between the carbon emission and cost of product, an improved genetic algorithm with a novel selection mechanism, which used the correlation function, is presented to optimize these parts in order to reduce both the carbon footprint and cost. In the end of the paper, a vacuum pump is taken as a case to verify the allocation method and the improved genetic algorithm, and the result shows the effective reduction of carbon footprint and cost. [ABSTRACT FROM AUTHOR]