In the process of scheme optimization, in order to eliminate the influence of random factor, it needs to conduct computer simulation of Monte Carlo. Therefore, it is proposed to introduce confidence ...interval into systemof-systems combat simulation, and confirm whether the Monte Carlo simulation finishes according to data sample generated in simulation process. According to characteristic of data sample, extend correspondingly confidence interval method, and under the condition of obtaining the solution meeting accuracy requirements, reduce simulation experiment times as far as possible. The simulation experiment results show that confidence interval extension method is able to possess self-adaptation control to Monte Carlo simulation.
The size and number density of Ω phase significantly affect the heat resistance of Al-Cu-Mg-Ag alloys and the ageing temper was reported to affect the heat resistance of Al-Cu-Mg-Ag alloy by changing ...the size and distribution of Ω phase. In this study, the over ageing heat treatment has been confirmed to notably affect the heat resistance of different Al-Cu-Mg-Ag alloys even when the solute contents are significantly different. However, slight over ageing can enhance the heat resistance of the alloy, while sever over ageing will decrease that. By combining systematic statistical quantitative characterization with guidance from the KWN modeling, the critical size of Ω at high thermal exposure temperature (rthermal*) is clarified to be the key factor influencing the coarsening of Ω. The closer the size of Ω after artificial aging is to the rthermal*, the better the heat resistance of the alloy. Therefore, the heat resistance of the alloy can be improved by adjusting the aging process to tune the size of the Ω phase to be close to the critical size at service temperature.
Functionalized polyamide 6 (PA 6) filament fabric with excellent thermal stability and UV resistance was copolymerized with methyl methacrylate (MMA) via in-situ grafting initiated by immobilized ...ascorbic acid and hydrogen peroxide. Grafting modification process was determined at 30 % of H2O2, at 70 °C for 60 min of duration, and the grafting degree could be tuned by adjusting the amount of MMA. Microscopic investigations confirmed the granular MMA was immobilized on the surface of PA 6 fibers. A strong peak at 1729 cm−1, assigning to CO stretching of ester bond of MMA, demonstrated MMA was successful grafted. The decomposition temperature of grafted PA 6 occurring at 444.6 °C, was 40 °C higher than that of pristine PA 6 (403.4 °C). Additionally, the introduction of MMA also improved the UV resistance of PA, more than 80 % decrease in transmittance of UVA band and UVB band with only 0.34 % grafting degree. Therefore, it can be concluded that in-situ grafting of MMA can endow PA 6 with excellent thermal stability and UV resistance. We believe that in-situ grafting of MMA would have important guiding significance for the fabrication of PA 6 based textiles with excellent thermal stability and UV resistance.
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•Functionalized PA6 was copolymerized with MMA via in-situ grafting initiated by immobilized H2A and H2O2 in aqueous solution.•The grafting degree can be tuned by the amount of MMA and the process parameters of in-situ grafting.•Thermal stability of grafted PA6 was promoted greatly with the Td 40 °C higher than that of pristine PA 6.•UUV resistance of grafted PA 6 was enhanced dramatically.
Research on CRISPR-Cas（clustered regularly interspaced short palindromic repeats-CRISPR associated protein） systems has led to the revolutionary CRISPR/Cas9 genome editing technique. However, for ...most archaea and half of bacteria, exploitation of their native CRISPR-Cas machineries may be more straightforward and convenient. In this study, we harnessed the native type I-B CRISPR-Cas system for precise genome editing in the polyploid haloarchaeon Haloarcula hispanica. After testing different designs, the editing tool was optimized to be a single plasmid that carries both the self-targeting miniCRISPR and a 600-800 bp donor. Significantly, chromosomal modifications, such as gene deletion, gene tagging or single nucleotide substitution, were precisely introduced into the vast majority of the transformants. Moreover, we showed that simultaneous editing of two genomic loci could also be readily achieved by one step. In summary, our data demonstrate that the haloarchaeal CRISPR-Cas system can be harnessed for genome editing in this polyploid archaeon, and highlight the convenience and efficiency of the native CRISPR-based genome editing strategy.
The stability of crown pillar is critical during the transition from open pit to underground mining. Mining-induced fractures in the pillar form water seepage channels, which can cause potential ...water inrush hazards. A microseismicity-based method to establish seepage channel network and assess damage state of rock mass in the pillar is proposed. The formation processes of seepage channels and associated rock failure mechanism were analyzed. First, the spatiotemporal evolution of the microseismic (MS) events was presented, based on which the development process of the fractured zone was determined. Second, moment tensor inversion (MTI) was utilized to interpret the focal mechanism of the MS events. A 3D rose diagram was utilized to measure the fracture orientations and determine the main fracture surfaces, and a fracture network was subsequently established. Meanwhile, the distribution characteristics of the fracture radii and volumes were discussed. The results show that shear fractures were dominant in pillar and accounted for more than 90% of all MS events. The overall damage tensor of the pillar was subsequently assessed based on the MS-derived fractures, and the maximum damage direction was determined. Third, a fast chronological expansion method was proposed to iteratively build a connected network with a combination of MS event locations and the corresponding fracture orientations. The MS-derived connected network was used to estimate the distances of event-to-event seepage, from which the shortest seepage channel from each individual event to the network was determined in chronological order. Seepage channels between hydraulic recharge and discharge points were inferred. These results could be helpful for better characterization of seepage channel development and the implementation of pillar reinforcement.
Red mud (RM) is a kind of industrial solid waste that is difficult to utilize，but it contains much alkali and has the ability of adsorbing some heavy metal ions. Due to these characteristics, red mud ...could be used as a raw material to develop a geopolymer based pervious concrete having rainwater purification function with granulated blast furnace slag (GBFS). Following this, influence of different factors including RM content, the sodium hydroxide to silicate (Na2O/SiO2) mole ratio, and the alkali concentration of the activator on the mechanical properties and ability of adsorbing heavy metal ions were investigated. XRD, SEM and EDS were then used to characterize the microstructure and morphology in attempt to reveal the mechanisms on the strength formation and on the adsorption of heavy metal ions. The results show that both the Na2O/SiO2 mole ratio and the alkali concentration of the activator had an obvious effect on the strength of the RM-GBFS-based geopolymer pervious concrete, but little effect on the adsorption of heavy metal ions. Moreover, with the increasing content of RM, the strength of the RM-GBFS-based geopolymer pervious concrete decreased, while the adsorption of heavy metal ions improved significantly. The possible reason for the excellent ability of adsorbing heavy metal ions can be attributed to the composition of the hardened RM-GBFS-based geopolymer system including geopolymeric gel, C-S-H gel with a lower Ca/Si ratio and some raw RM particles that have great ability of adsorbing heavy metal ions. As the compressive strength at 28 d of the RM-GBFS based geopolymer pervious concrete (containing 30 wt% RM in the geopolymer) can reach 18.53 MPa, it can applied in the light road pavement in China, and this pervious concrete has been demonstrated to have the function of rainwater purification due to its higher removal of heavy metal ions from solution that can reach 53%–77%. Therefore, it can be concluded that it is feasible to employ RM for manufacturing geopolymer-based pervious concrete with function of rainwater purification.
Coal tar residue (CTR) is acknowledged as hazardous industrial waste with high contents of carbon and toxic polycyclic aromatic hydrocarbons (PAHs). Microwave-assisted extraction for separating tar ...and residue in CTR was investigated to reduce the content of PAHs. The key operating factors such as solvent type, solvent addition amount, radiation temperature, and radiation time in the extraction process were evaluated. Results showed that extreme extraction performance in the solvent with cyclic structure was attained, and an enhancement in extraction efficiency was achieved in elevated solvent addition amount, radiation temperature, or radiation time in a certain range. The optimized conditions were determined as benzene was chosen as extractant, solvent-solid ratio of 5:1 mL/g, radiation temperature of 75 °C, and radiation time of 10 min. Relative extraction efficiency of CTR and reduction efficiency of 16 priority control PAHs were 28.70% and 92.82%, respectively. According to the characterizations of extracted residue (MCTR) and tar (MCT) under optimum experimental conditions, it is possible to convert them into value-added products (carbon materials, solid fuels, or chemicals). Solid-oil separation via microwave-assisted extraction is a safe and high-valued utilization approach for CTR.
•Reducing the content of PAHs in coal tar residue by microwave-assisted extraction was studied.•Extraction yield of microwave-assisted extraction was up to 28.70%.•The highest reduction efficiency of 16 priority control PAHs was 92.82%.
Recent progress on visual question answering has explored the merits of grid features for vision language tasks. Meanwhile, transformer-based models have shown remarkable performance in various ...sequence prediction problems. However, the spatial information loss of grid features caused by flattening operation, as well as the defect of the transformer model in distinguishing visual words and non visual words, are still left unexplored. In this paper, we first propose Grid-Augmented (GA) module, in which relative geometry features between grids are incorporated to enhance visual representations. Then, we build a BERT-based language model to extract language context and propose Adaptive-Attention (AA) module on top of a transformer decoder to adaptively measure the contribution of visual and language cues before making decisions for word prediction. To prove the generality of our proposals, we apply the two modules to the vanilla transformer model to build our Relationship-Sensitive Transformer (RSTNet) for image captioning task. The proposed model is tested on the MSCOCO benchmark, where it achieves new state-of-art results on both the Karpathy test split and the online test server. Source code is available at GitHub 1 .
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