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Landslide is a common dynamic large-deformation disaster of mobilized soils, which poses a serious threat to the lives and economic properties of surrounding people. Both the strain-softening effect and spatial variability of soil are reported to have significant impacts on landslide behaviors. This study investigated the coupled effect of strain softening and spatial variability on the occurrence, evolution, and runout behavior of landslides induced by seismic loads, using three-dimensional (3D) large-deformation finite-element method. The results show that both the strain-softening behavior and spatial variability of soil dramatically affect the sliding velocity and runout distance. Their coupled effect further weakens the soil strength, resulting in a larger runout distance. Secondly, the runout distance in the 3D deterministic analysis is always smaller than the minimum value in the corresponding random analysis, which completely differs from the result from the two-dimensional (2D) analysis. This finding indicates that 2D analysis can result in a conservative estimation on the runout distance for spatially variable soils and highlights the advantages of 3D modeling on landslides. Thirdly, a linear formula was proposed to quantify the runout distance based on the horizontal peak acceleration, which can provide some guidelines for the safety design in practical slope engineering.

Reports have pointed out that nearly 50% of the global total energy demand for buildings is used for daily heating and cooling. Therefore, it is very important to develop various high-performance thermal management techniques with low energy consumption. In this work, we present an intelligent shape memory polymers (SMPs)-based device with programmable anisotropic thermal conductivity fabricated by a 4D printing technique to assist in thermal management with net zero energy. Highly thermal conductive BN nanosheets were textured in a poly (lactic acid) (PLA) matrix by 3D printing, and the printed composites lamina exhibited significant anisotropic thermal conductivity. The direction of heat flow in devices could be switched programmably, accompanying the light-activated deformation controlled by grayscale of composite, which was demonstrated by the “windows” arrays composed of in-plate thermal conductivity facets and SMPs-based hinge joints, achieving the programmable movement of opening and closing under different light conditions. Based on solar radiation-dependent SMPs coupled with the adjustment of heat flow along anisotropic thermal conductivity, the 4D printed device has been proved in concept for potential applications in thermal management in a building envelop for dynamic climate adaptation, taking place automatically based on the environment.

Landslide is a uniquely dynamic large-deformation process that can present serious threat to human lives and infrastructures. The natural soil properties often exhibit inherent spatial variability, which affects the landslide behavior significantly. This paper focuses on combined Monte Carlo simulation and three-dimensional (3D) dynamic large-deformation finite-element (LDFE) analysis using the coupled Eulerian-Lagrangian method to investigate the whole runout process of landslide induced by the earthquake in spatially varying soil. The results from LDFE analysis show that the mean value of runout distance in spatially varying soil is significantly higher than that of the deterministic value obtained from a homogeneous slope due to the slope failure developed along the weakest path in soils. The mean runout distance increases and converges with increasing slope length in 3D-LDFE stochastic analysis. The advantages and necessities of 3D-LDFE analysis were illustrated by comparing it with two-dimensional (2D) LDFE analysis of landslide in spatially varying soil. The results show that the calculated mean runout distance using 3D-LDFE method is at least 16.1% higher than that calculated using 2D-LDFE analysis. Finally, a linear regression formula was established to estimate the mean runout distance of landslide due to horizontal inertia acceleration. Such a formula may facilitate the risk assessment of landslide in practical engineering.

Thermodynamic interactions in binary blends of a copolymer containing diene and olefin repeat units and a polyolefin were explored, through measurements of the effective binary Flory–Huggins intera...

Herein, we study comparatively melt-memory effects on recrystallization of two sets of linear low-density polyethylenes (LLDPE) synthesized with Ziegler–Natta (ZN-LLDPE) and with metallocene cataly...

Earthwork excavator, as an all-terrain and high-efficiency earthwork excavation equipment, has been widely used in earthwork sites. It is very necessary to analyze the work of earthmoving excavator by means of machine vision. In this paper, the action segmentation method based on long video was applied to the analysis and recogniton of the excavator’s action, and compared with other two current best action segmentation models using the real construction site video. Firstly, the sequence features of the excavator’s work video obtained at the cnstruction site was extracted through 3D convolution method, and then two differernt networks with the extracted sequence features were trained and tested. The experimental results showed that the average frame accuracy of MS-TCN model and ASRF model in excavator action segmentation were 82.6490% and 86.1042% respectively. However, for the recognition task under different working environment, the performance of the two models is quite different. The experimental results manifest that the motion segmentation model based on long video reached good results in excavator motion recognition in earthmoving operation. And it is helpful to analyze the long video working behavior sequence of excavator. This research contributes to the identification of critical elements that explains serial action and to the development of a new application scenario for vision-based behavior segmentation network. Additionally, the results of this study were helpful to automatically analyze the working efficiency and monitor the productivity of earthmoving excavators. Using this kind of data-driven decision can improve the work efficiency of earthmoving excavator and promote the project progress.

Increasing the efficiency of cross-coupling reaction under mild condition and easy catalyst separation is a key issue in the realistically chemical industry application. Here, we report that the fiber-supported Pd catalyst shows a high activity and selectivity for the cross-coupling reaction of terminal alkynes. The yield of the asymmetric 1,3-diyne can reach 83% at 80 °C and 4 h reaction time in N,N-dimethylacetamide (DMAc), and about 87% selectivity. XPS, EDS and SEM results show that Pd metal ions are successfully loaded onto the fiber surface and are reduced to produce active component of Pd (0) by terminal alkyne in reaction. We consider that Pd (0) is the active center of the catalytic cycle, the coordination of the fibers can stabilize Pd particles on the supports and increases the catalytic activity of Pd catalysts. Cu (I) plays a synergistic catalytic role. This study provides an alternative pathway for the high efficient cross-coupling reaction.

Salmonella is a type of serious foodborne pathogenic bacterium that threatens the food safety worldwide. In this study, a fluorescence probe-based recombinase polymerase amplification analytical method (exo RPA) was developed for the sensitive and specific detection of Salmonella enterica (S. enterica). The primers and probe for this method were designed based on the iroB gene of the bacterium. The exo RPA reaction could detect as low as 102 copies of template DNA per reaction or 2.2 × 103 CFU/mL of S. enterica, and SPSS probit regression analysis indicated the limit of detection (LOD) at 95% probability of the exo RPA assay was 2.0 × 103 CFU/mL. Moreover, the exo RPA assay could successfully differentiate S. enterica from all the tested non-Salmonella strains. Importantly, this method is highly reliable; the DNA from other bacteria or food complex matrices has no obvious effect on the S. enterica exo RPA. Besides, positive signal could be obtained from the chicken or egg sample inoculated with 2.2 × 101 CFU/mL of S. enterica after 4- to 6-h enrichment at 36 °C. Therefore, this study describes a rapid test method for S. enterica, which is expected to be beneficial for monitoring trace S. enterica in real food products.

The high intra class diversity of remote sensing image scene often leads to the problem of difficult classification of remote sensing image scenes. Therefore, this paper proposes the CA-EfficientNetV2 model, embedding the coordinate attention into the head of the EfficientNetV2 network to enhance the classification effect. The coordinate attention is used to generate the position relationship between image spaces and channels so as to learn features efficiently. We trained three improved models CA-EfficientNetV2-S, CA-EfficientNetV2-M and CA-EfficientNetV2-L on UC Merced remote sensing dataset respectively. The classification accuracy reached 99.55%, 97.49% and 97.09% respectively. Among them, CA-EfficientNetV2-S had the best effect, which was improved by 0.8% compared with the original network.

The mechanism of liquid-liquid phase separation (LLPS) is investigated in a random ethylene 1-hexene copolymer (E/H) with a broad comonomer content distribution. SANS measurements were first carried out using the original resin with deuterium added via direct isotope exchange to preserve the original branching distribution. Upon lowering the melt temperature, the upshift of SANS profile observed only below a critical scattering vector is consistent with the signature of nucleation and growth during LLPS in the metastable region. Differences in branching distribution between the original broad resin and a broad multi-components blend of narrow E/H copolymers studied previously, result in slower LLPS dynamics in the former that has a more continuous change of comonomer content between molecules. Time-resolved light scattering and light transmittance measurements in the metastable region of the broad resin, reveal the nucleation and growth stages of LLPS. Dissolution of crystalline melt-memory, associated with an inversion of the crystallization rate with decreasing the temperature of the initial melt, is found to occur mainly within the LLPS induction period and is associated with concentration fluctuations prior to the LLPS nucleation step. The typical sea-island morphology associated with LLPS via nucleation and growth is observed under bright-field optical microscopy after one-day annealing in the metastable region.

Full-flow penetrometers (ball and T-bar) are widely used for measurements of strength characteristics of clayey soils in offshore field investigations and laboratory tests. However, the accuracy of the estimated undrained shear strength is hampered by: (1) the drastic variation of the bearing factor for the penetrometer at shallow and transitional penetration depths where full-flow mechanisms are not achieved; and (2) the strain-softening of the soil, which results in a degradation of the estimated strength. This study conducted LDFE analyses to simulate the entire penetration process of full-flow penetrometers in strain-softening soils from shallow to deep embedment depths. Parametric studies were performed to investigate the effects of varied factors on the bearing factor and failure mechanism during the penetrometer penetration. Based on the LDFE analyses, empirical formulas are established to represent the critical penetration depths in the strain-softening soil, which are used to correct the bearing factor at shallow penetration depths. The discrepancies of the transitional failure mechanism and the trapped cavity bearing factor between ball and T-bar are emphasized. Finally, a back-analyses framework is proposed to estimate the strength parameters (including the original undrained shear strength prior to any strain-softening, and the strain-softening parameters) based on the measurements of the penetrometer during the first penetration from shallow to deep embedment depths. Through a series of model tests, the reliability of the back-analyses framework is validated.

Aiming to understand the inversion of crystallization kinetics observed by DSC, detailed SANS investigations of the melt structure of a broadly distributed ethylene–1-hexene copolymer have been undertaken in a wide range of temperatures that were reached either by heating the solid or cooling from the homogeneous melt state. In both cases, the observed SANS signal transitions from a scattering cross section consistent with a homogeneous melt state (high temperature range) to an intensity that in the low Q region displays the characteristics of the Porod region for particles dispersed in a homogeneous matrix (low melt temperature range). The latter structure is consistent with demixing of the highly branched molecules and corroborates the postulated liquid–liquid phase separation (LLPS) as an explanation for the peculiar crystallization kinetics observed by DSC. The solution temperature is found at 160 °C by heating the solid and at 150 °C when cooling from the one-phase melt, thus denoting the effect of c...

A novel full-range soft-switching full-bridge (FSFB) cycloconverter-type high-frequency-link inverter (CHFLI) with active snubber network is proposed. By adding an auxiliary inductor in primary-side DC/AC converter and adopting centre-tapped transformer structure, the proposed FSFB-CHFLI achieves zero voltage switching (ZVS) for all switches under different operating conditions from light load to rated load, which benefits with high efficiency and high switching frequency. The secondary-side active snubber network is utilised to recycle leakage inductor energy and suppress voltage spikes caused by the resonance of the leakage inductor and the parasitic capacitance of switch. The commutation overlap strategy is adopted to guarantee complete ZVS turn-on and ZVS turn-off of bidirectional switches. Experimental results of a high efficient and high switching frequency (200 kHZ) prototype are presented to verify the analysis results of the proposed FSFB-CHFLI.

A novel soft-switching step-up/down DC–DC converter is proposed, which generates symmetric bipolar outputs while maintaining the grounded capability. The proposed converter consists of a zeta converter cell and a buck–boost converter cell, sharing an inductor and a power switch. High efficiency is achieved by zero voltage switching for all switches. Meanwhile, by connecting one load between positive and negative output terminals, high voltage gain can be achieved. Experimental results of a 3.7 V battery input and ±10 VDC/10 W outputs prototype are presented to verify the analysis results of the proposed converter.

A two-channel single-stage switching amplifier (SSA) based on high-frequency link inverter is proposed. The audio input signals are modulated by phase shift between primary-side switches and secondary-side switches, thus independent amplifications of two channels can be obtained. Benefiting from multiplexing of primary-side power switches for two channels, only a half bridge inverter is utilised at primary side. Clamp circuits at the secondary side of transformer eliminate spike voltages across the secondary-side switches during the current commutation of the cycloconverters. Zero voltage switching of primary-side switches and clamp switches are achieved by utilising magnetising inductor current. A 320 V/250W prototype is presented to verify the analysis results of the proposed two-channel SSA.

A high efficiency single-stage switching amplifier based on high-frequency link inverter is proposed. Bipolar phase shift modulation is adopted in the proposed switching amplifier. Auxiliary circuits including freewheeling diodes, clamp capacitors and active clamp bridge (ACB) are added to provide a current flowing path for the inductor current during the dead time of the bidirectional switches. The ACB is synchronised with primary-side switches to absorb the leakage inductor energy and clamp the secondary-side transformer voltages. With single-stage conversion and leakage inductor energy recycle, high efficiency of the proposed switching amplifier is achieved. A 5 V/25 W prototype is presented to verify the analysis results of the proposed switching amplifier.

The present study aimed to investigate the antiulcer activities and mechanisms of action of an active ingredient group (AIG) of Modified Xiao Chaihu Decoction (MXCD). The gastroprotective action of the AIG was studied in ethanol-induced, pylorus ligature-induced, and acetic acid-inducedin vivogastric ulcer models. The enzyme-linked immunoadsorbent assay (tumor necrosis factor-α(TNF-α), prostaglandin E2(PGE2), and epidermal growth factor (EGF)), nitrate reductase assay (nitric oxide (NO)), western blot analysis (Bax, Bcl-2, cleaved-caspase-3, and cleaved-PARP (poly (ADP-Ribose) polymerase)), histological analysis (HE), and immunohistochemical analysis (HSP-70, p-AKT, and PCNA) were used to evaluate the anti-inflammatory, antiapoptotic, and healing properties of AIG. Numerous mechanisms are involved in the antiulcer activity of AIG, including the increase of PGE2, NO, and EGF content and a reduction in TNF-αlevels. The upregulation of HSP-70, p-AKT, and PCNA seems to be directly linked to the healing effect of AIG. Bax, Bcl-2, cleaved-caspase-3, and cleaved-PARP also play a key role in this process. The AIG exerted gastroprotective effects by reducing antisecretory, anti-inflammatory, and antiapoptotic mechanisms. In addition, it promotes cell proliferation. Therefore, activation of the PI3K/AKT signaling pathway may play an important role in cell proliferation.

Narrow metallocene-made random ethylene copolymers display a strong memory effect of crystallization above their equilibrium melting point akin to the melt memory effect observed in model ethylene–1-butene copolymers. The onset temperature for self-nucleation or surviving self-seeds displays a bell shape with increasing comonomer content with a maximum at ∼2 mol % branches. Self-seeds do not survive at temperatures above the equilibrium melting point for homopolymers and copolymers either with very low branching or with a branching content >4.5 mol %. The self-seeds are associated with clusters of ethylene sequences that remain in the melt in close proximity and accelerate a subsequent crystallization, as observed by higher crystallization peak temperatures and higher nucleation density. Contrasting this behavior, commercial ethylene–1-alkene copolymers with a broad, bimodal comonomer distribution display an inversion of the crystallization rate in a range of melt temperatures where narrow copolymers show...

Full-flow penetrometers, Ball and T-bar, have been widely used to measure the undrained shear strength of offshore clayey soils in both laboratory and in situ tests. The penetration process of Ball or T-bar penetrometer is a large deformation geotechnical problem, which results in the surrounding soil partially remolding and softening. The soil disturbance influences the penetration resistance and hence leads to an underestimation of the undrained shear strength, which is a critical factor for offshore geotechnical design. To investigate the soil strain-softening behavior during the first penetration, large deformation finite element (LDFE) analyses were performed to simulate the penetration process of T-bar and Ball in the strain-softening clay. The thin layer element was employed to simulate the complex contact behavior between the penetrometer and the surrounding soil, thus the strain-softening behavior can be considered at the interface between penetrometer and soil. This study aims to investigate the effects of soil strain-softening and interface roughness on the penetration resistance during the first penetration of full-flow penetrometers. Based on the numerical results, relative comprehensive formulas considering the soil strain-softening parameters and the interface roughness factor have been proposed to evaluate the strain-softening factors, which can be used to estimate the soil intact undrained shear strength and the strain-softening parameters. Finally, the proposed formulas were verified by experimental results and were used to estimate the intact undrained strength of soft clay.

A Single-Stage isolated bi-directional power amplifier (SSA) is proposed which achieves high level of integration, high efficiency and low component without bulky dc link capacitors. The SSA comprises an input active bridge and an output cycloconverter with an active clamper circuit, linked by a high-frequency isolation transformer. The uni-polarity and bi-polarity phase-shifted modulation strategies are deeply and comparatively investigated. The operation principles of zero voltage switching (ZVS) and duty cycle loss are analyzed and derived specifically. The simulation and experimental results on a 80W single stage amplifier are presented to validate the theoretical analyses and operation principles.

Conventional polymers contain various chemical, geometrical, and stereo-optical sequence irregularities along the backbone chain, which can be treated as noncrystallizable comonomers in statistical copolymers. For statistical copolymers, the link between chemistry (copolymerization to characterize statistical copolymers) and physics (crystallization to determine structures and properties) has recently been enhanced. This review discusses how the crystallization behavior and resulting semicrystalline structure of statistical copolymers are affected by the various microstructure parameters of their comonomers, such as content, distribution along or even among polymer chains, and size (determining their inclusion in or exclusion from the crystallites). The discussion of crystallization is focused on its interplay with component segregation at three different length scales: monomer, monomer sequence, and macromolecule. The first two mainly occur in homogeneous copolymers, whereas the last one is only operative for heterogeneous copolymers. In addition, some unique phenomena such as strong memory effects and (cross)fractionation are discussed briefly.

Attention has been focused on long-distance pipeline disasters control for a long time. Summing up the lessons of the past, the Sino-Burma pipeline natural disaster control abandoned the idea of passive management and introduced a full life cycle and active protection concept. In the early stages of the construction, parties cooperated to select and optimize the pipeline and checked the survey reports carefully to make sure the preliminary data were right. In the design of geological disaster prevention, one should: (1) enhance communication with other professions and cooperate with each other in order to achieve optimal treatment results and cost savings; (2) create a dynamic design philosophy to make sure the design guides the construction and is optimized in the construction; (3) carry out the design evaluation, summarizing past experience in time; and (4) use run-time monitoring and real-time protection.