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The macro-invertebrate is an important part of the aquatic food web of urban rivers, and it is of great significance in understanding its ecological suitability for the stability of river ecosystems. Previous studies, such as those that have conducted suitability index and canonical correspondence analyses (CCAs), have widely used a macro-invertebrate suitability analysis; however, these studies can only confirm a few coupling relationships between the environment and macro-invertebrates. In our study, one-way ANOVA, HCA, PCA and GAM models were used to explain the differences in the spatial and temporal distribution of environmental factors, as well as to reduce data redundancy. A response curve of the critical environmental factors and macro-invertebrates was constructed, and the nonlinear relationship between these factors and benthic animals was quantified to analyze the ecological threshold of the macro-invertebrates. The study area was the Majiagou River, Harbin, China. The results show that COD had significant seasonal differences due to complex hydrological conditions, and most of the water quality factors had spatial differences. The GAM model explained 60% of the Margalef diversity index (MDI) variance. The relationship between chlorophyll-a and MDI was unimodal, and MDI and NH4+-N essentially showed a negative correlation; when the total nitrogen (TN) value reached 5.8 mg/L, MDI reached its peak. When MDI was higher than the mean value, the chlorophyll-a range was 18.1 μg/L~83 μg/L. The NH4+-N was less than 1.8 mg/L, and TN was 1.8~6.8 mg/L. This study provides a reference for the comprehensive management of urban river ecosystems.

The emergence of abnormal events (e.g. personnel abnormalities, equipment failures, etc.) on the assembly floor of complex products can seriously affect normal assembly progress. In response to the...

To realize the deep integration of complex product manufacturing and operation and maintenance processes, while eliminate the phenomenon of information islands generated in the manufacturing and operation and maintenance links, in the light of the lack of in-depth integration in the manufacturing and operation and maintenance process of complex products. With the help of digital twin technology, this paper puts forward the overall framework manufacturing and operation and maintenance integration of a complex product based on digital twin and the system integration mode of virtual and real integration. The solutions of complex product integration of manufacturing and operations and maintenance, data fusion, modeling and simulation, and manufacturing plant operation mode based on digital twin are analyzed. The key technologies based on digital twin deep integration of manufacturing and operation and maintenance, fault prediction, and knowledge base/case library construction are discussed. Finally, combined with the fault prediction case of a certain type of electric multiple units (EMU) bogie, the associated operation mode between the operation and maintenance process of the EMU and the manufacturer is demonstrated, which proves the feasibility and effectiveness of the integration method.

Development of multifunctional materials and devices has garnered enormous attention in the field of organic optoelectronics; nevertheless, achieving high mobility together with strong luminescence in a single semiconductor remains a major bottleneck. Here, a new multifunctional semiconductor molecule, 2,7-diphenylbenzo[4,5]thieno[3,2-b]benzofuran (BTBF-DPh), that integrates high charge transporting [1]benzothieno[3,2-b][1]benzothiophene with a strongly emissive furan group, is synthesized and applied in three types of optoelectronic devices, including organic light-emitting diodes (OLEDs), organic field-effect transistors (OFETs), and organic phototransistors (OPTs). OLEDs based on BTBF-DPh as the emissive layer showed a blue emission with CIE coordinates of (0.151, 0.069) and a maximum current efficiency of 2.96 cd A-1 with an external quantum efficiency of 4.23%. Meanwhile, OFETs fabricated with BTBF-DPh thin film manifested a carrier mobility of 0.181 cm2 V-1 s-1, which is comparable to that of thiophene-based counterparts. Additionally, BTBF-DPh-based OPTs exhibited a maximum responsivity and detectivity of 2.07 × 103 A W-1 and of 5.6 × 1015 Jones, respectively. On the one hand, our rationally designed material, BTBF-DPh, has a dense and close-packed structure with an extended π-conjugation, facilitating charge transport through adjacent molecules. On the other hand, the weakened dipole-dipole interactions between BTBF-DPh molecules that resulted from the unambiguous J-aggregation and reduced spin-orbit coupling caused by replacing sulfur atom significantly suppress the exciton quenching, contributing to the improved photoluminescence performance. These results validate that our newly developed BTBF-DPh is a promising multifunctional organic semiconductor for optoelectronic devices.

The emergence of uncertainty factors will exert a strong influence on the accuracy of workshop scheduling. Digital twin’ technology and planning and scheduling are integrated to form a planning and scheduling system based on digital twin, which can effectively use the concept of twin to carry out all-around management and control of the uncertain factors in production activities so that the planning and scheduling scheme in the production process can accurately guide the actual production. Firstly, the system establishes management and control mechanism of planning and scheduling system based on digital twin. Second, it establishes a digital twin model of the planning and scheduling system for the management and control mechanism. Finally, the key technology of the planning and scheduling system is expounded, which mainly includes the perception and collection of total production factor information and the planning and scheduling prediction. In order to verify the validity of the scheme, the planning and scheduling system suited for the enterprise is designed and developed in combination with the frame workshop.

Device integration is among the current research trends in the area of organic electronics and the development of multifunctional materials is crucial to accelerate the progress of integrated devices, such as organic light-emitting transistors (OLET), organic field-effect optical waveguides (OFEW) and organic electrofluorochromic (OEFC) devices. Herein, two multifunctional materials with different side chains, 2-(4-octyloxyphenyl)anthracene (AntPh-OC8) and 2-(4-octylphenyl)anthracene (AntPh-C8), based on the concept of combining liquid crystal (LC) materials featuring facile processability, highly ordered alignment and effective charge transport and an anthracene conjugated core with strong fluorescence, are designed and successfully synthesized. The photoluminescence quantum yield (PLQY) of AntPh-OC8 and AntPh-C8 is determined to be 40.9% and 37.6%, respectively, which approaches nearly 2-fold that of 2-phenylanthracene (AntPh). Organic light-emitting diodes (OLED) based on AntPh-OC8 confirmed its solid-state blue emission with a current efficiency (CE) of 1.82 cd A−1, whereas the corresponding organic field-effect transistors (OFET) demonstrated the highest hole mobility of up to 2.59 cm2 V−1 s−1. Organic phototransistors (OPT) comprising AntPh-OC8 and AntPh-C8 revealed efficient photoresponsive characteristics of these newly developed materials. These demonstrations indicate the widespread potential of our newly developed materials for applications in multifunctional integrated devices. Moreover, these results indicate the encouraging role of side-chain engineering in the improvement of charge transport and fluorescence characteristics of anthracene derivatives.

Aiming at the problems of poor periodicity of workshop material distribution, difficult prediction of station material demand time node and redundant distribution route, this paper proposes a model construction method of material distribution system based on digital twin. Build a material distribution control mode based on digital twin, and establish a full cycle material distribution mechanism on this basis to comprehensively optimize the distribution cycle from the material preparation stage, dynamic replenishment stage and data transmission stage of adjacent distribution cycles. Build the digital twin model of material distribution system, establish the material demand time node prediction operation mechanism based on LSTM, accurately predict the station material demand time node, establish the material distribution route optimization model with the lowest total cost, and optimize the AGV route. Finally, it is applied to the asynchronous card line workshop of A enterprise to verify the effectiveness of this method.

Development of multifunctional materials and devices has garnered enormous attention in the field of organic optoelectronics; nevertheless, achieving high mobility together with strong luminescence in a single semiconductor remains a major bottleneck. Here, a new multifunctional semiconductor molecule, 2,7-diphenylbenzo[4,5]thieno[3,2

Sodium penetration into carbon cathodes is an important cause of cell failure and efficiency loss, but it is a formidable task to unravel the detailed mechanism experimentally. Combined with MD simulation and DFT calculation, several diffusion coefficients were acquired to quantitatively analyze the behaviors of sodium penetration for the first time. Especially, the transport diffusion coefficient of sodium vapor in the large-scale realistic anthracite cathode model was calculated as 6.132 * 10−10 m2/s, which was in outstanding agreement with experimental results. Owing to lower diffusion energy barrier, sodium was found to migrate faster along the grain boundaries than the other two solid diffusion pathways. The striking difference of corresponding diffusion coefficients in the order of magnitude indicated that sodium may migrate predominantly by vapor migration, rather than through solid diffusion, at least in anthracite cathodes with high porosity. This fundamental research would contribute to the understanding of sodium penetration mechanism and the optimization of cathode industry in the future.

In this work, a novel hole transport material (HTM) based on benzo[4,5]thieno[3,2-b]benzofuran (BTBF) core with diphenylamine group, BTBF-DPA, was synthesized and systematically studied. BTBF-DPA showed high carrier mobility, good thermal stability and high triplet energy as 2.99 eV. Green phosphorescent organic light-emitting diodes (PhOLEDs) using BTBF-DPA were fabricated which displayed outstanding electroluminescent performance with a low turn-on voltage of 2.4 V, the maximum current efficiency (CE) of 123.6 cd A−1, power efficiency (PE) of 136.6 lm W−1, and external quantum efficiency (EQE) of 34.1%. Red PhOLEDs with BTBF-DPA also demonstrated a maximum PE of 40.1 lm W−1, and EQE of 24.9% with a low turn-on voltage of 2.3 V. Besides, blue fluorescence OLEDs presented a maximum PE of 4.9 lm W−1, EQE of 5.2% and small efficiency roll-off of 11.5% at 10000 cd m−2. RGB-OLEDs with BTBF-DPA outperformed the reference devices based on NPB as HTM that has been widely utilized. What's more, life-time of RGB OLEDs were T99 = 70 h at 10000 cd m−2, T70 = 60 h at 10000 cd m−2, T80 = 125 h at 5000 cd m−2, respectively. These results imply that BTBF-DPA is a promising HTM for OLEDs.

Human copper transporter 1 (hCtr1) transports copper and silver by a homotrimer. The protein contains three transmembrane domains in which the second transmembrane domain (TMD2) is a key component lining the central pore of the trimer. The MXXXM motif in the C-terminal end of TMD2 plays a significant role in the function of hCtr1. In this study, we characterized the structure and assembly of isolated TMD2 of hCtr1 in sodium dodecyl sulfate (SDS) micelles and the interaction of the micelle-bound peptide with silver ion using nuclear magnetic resonance, circular dichroism, isothermal titration calorimetry and electrophoresis techniques. We detected the formation of a trimer of the isolated hCtr1-TMD2 in SDS micelles and the binding of the trimer to Ag(I) by a chemical stoichiometry of 3:2 of peptide:Ag(I). We showed that either an intensive pretreatment of the TMD2 peptide by 1,1,1,3,3,3-hexafluoro-2-propanol solvent or a conversion from methionine to leucine in the MXXXM motif changes the aggregation structure of the peptide and decreases the binding affinity by 1 order of magnitude. Our results suggest that the intrinsic interaction of the second transmembrane domain itself may be closely associated with the formation of hCtr1 pore in cellular membranes, and two methionine residues in the MXXXM motif may be important for TMD2 both in the trimeric assembly and in a higher-affinity binding to Ag(I).

Silver is a toxic metal. It can accumulate in tissues as a contaminant in foods and air. The human copper transporter 1 (hCtr1), as an uptake protein of copper, plays an important role in the accumulation of silver in mammalian cells. The extracellular N-terminal domain of hCtr1 contains two methionine-rich motifs, in which the second methionine-rich motif (M2) has been demonstrated to be crucial for uptake of Ag(I) and Cu(I). In the present work, the structure of an M2-inclusive peptide from hCtr1 34–53 in SDS (sodium dodecyl sulfate) micellar solution and the interaction of the micelle-bound peptide with Ag(I) were studied using nuclear magnetic resonance (NMR), isothermal titration calorimetry (ITC) and circular dichroism (CD) methods. The details of the binding site, affinity, stoichiometry and thermodynamics of the interaction between the micelle-bound peptide and Ag(I) were explored using NMR and calorimetric measurements titrated by Ag(I), and the role of each methionine residue in the binding of M2 motif with Ag(I) was estimated by individual substitution of methionine by alanine. It was revealed that the hydrophobic C-terminal region of the peptide folds as an α-helix and is embedded in SDS micelles, while the N-terminal region containing the Met motif locates at the surface of the micelles and binds Ag(I) mostly by Met40, Met41, Met43 and Met45. Differences between the peptide in the micelle-bound state and the peptide in the solution state with regards to the binding affinity, stoichiometry and thermodynamics were observed. It is suggested that the interaction between the extracellular domain of hCtr1 and membrane surface may play an important role for the binding structure and binding affinity of the M2 motif with Ag(I).