Search

［Objective］Since the implementation of the Shanghai Master Plan (2017-2035), with the development of five new Shanghai towns (Jiading, Qingpu, Songjiang, Fengxian, and Nanhui) and the Yangtze River Delta integration ascending to national strategies, Shanghai urban rail transit planning network is also undergoing further adjustments. Among them, circle lines and express lines (shorten as circle/express lines) are the focus of discussion, and it is necessary to study the functional planning, passenger flow characteristics and planning principles of circle/express lines. ［Method］Using the passenger flow data of existing urban rail transit lines, the characteristics and functions of circle/express lines passenger flow are analyzed; by comparing the previous research conclusions and actual operation status of circle/express lines, the planning experience of circle/express lines is summarized. Based on the urban development plan requirements in the new era, the shortcomings of circle/express lines in the existing plan are analyzed, and the functional requirements and planning principles of them in the new round of plan adjustments are proposed. ［Result & Conclusion］The passenger flow carried by the circle line is divided into three categories: passenger flow along line service range, transit passenger flow and arrival/departure passenger flow of the line. The corresponding circle line can play service functions for the above three scenarios. In addition to the existing circle line—Shanghai Rail Transit Line 4, the second circle line can be planned to meet the needs of passenger flow distribution along the line. It is recommended that the second circle line can be located between the middle and outer ring roads, making use of the planned Shanghai Rail Transit Line 26, and better closer to the middle ring line. The planning of express lines from suburbs to central urban area should be further strengthened. There are direct access and hub access two forms of express lines entering the central urban area network. Hub access requires highly convenient hub station for this purpose, while direct access to the network features relatively high cost. The corresponding indicator calculation method of express line travel time may be selected based on the connection closeness degree between new towns and the central urban area.

Herein, poly(pentanediamine terephthalamide) (PA5T) homopolymer was synthesized via a salt-forming reaction+solid state polycondensation method using bio-based 1,5-pentanediamine and terephthalic acid as the primary raw materials. To address the issue of its narrower processing window, poly(hexamethylene terephthalamide)(PA6T), which also cannot be melt processed due to the processing window is negative, was introduced into its molecular chain to synthesize poly (pentanediamine/hexanediamine terephthaloyl) (PA5T-co-6T) copolymers. The structures were investigated by Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance carbon spectroscopy (13C-NMR). Furthermore, the melting temperature, crystallization temperature, thermal stability, and crystal growth mode of the polymer were tested and analyzed using differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and wide-angle x-ray diffraction (WAXD), respectively. The results demonstrate that the crystal growth mode gradually changes from three-dimensional spherical growth to two-dimensional disk-like or three-dimensional spherical growth with the increase of 6T chain segment content. Simultaneously, the crystallization temperature, melting temperature, and crystallization rate of the polymer all showed a trend of decreasing first and then increasing, which was due to the combined effects of the increase in the content of 6T chain segments on the molecular-chain structure and crystal structure of the polymer. Bio-based PA5T-co-6T has excellent heat resistance and a wider processing window than PA5T and PA6T, which possesses great application prospects in the fields of automotive, electronic appliances, and LED optics. [ABSTRACT FROM AUTHOR]

High‐performance microwave absorption (MA) materials are attracting growing attention to solve the expanded electromagnetic interference problems. Herein, zeolitic imidazolate organic frameworks (MOF)‐67 (ZIF‐67) are grown in situ on the sheet of graphene oxide (GO) through the coordination of Co2+ with oxygen functional groups. Through carbonization in an inert atmosphere, Co@carbon polyhedra (Co@CP)‐decorated reduced GO composites (Co@CP‐rGO) with a large number of heterogeneous interfaces are successfully obtained. The composites demonstrate excellent MA performance. With a filler loading of 10 wt%, the optimal minimum reflection loss (RL) of the composite can reach −54.6 dB. More importantly, the composites with thickness of 3.5 and 2.5 mm show the effective absorption bandwidth (RL < −10 dB) of 4.75 GHz (8.18–12.93 GHz) and 6.56 GHz (11.44–18 GHz), fully covering the X‐ and Ku‐band. It is proposed that the synergistic effect of multiple dielectric loss, magnetic loss, reflections and scattering contributes to the high MA performance. [ABSTRACT FROM AUTHOR]

The structures and properties of the electric double layer (EDL) on zinc (Zn) anodes significantly influence the cycling and rate performance of aqueous Zn batteries (ZBs). Here, a strategy is reported to regulate the EDL structure through work function (Wf) engineering to effectively enhance the electrochemical performance of ZBs, which is enabled by electrolyte‐tailored growth of heterogenous metal with a large Wf on the Zn anode. The metal‐to‐metal charge transfer in heterostructured Zn metal induced by the disparity of Wf increases the surface charge density, which enriches the Zn ions and shortens the thickness of EDL. The compressed EDL weakens the repulsive force of Zn deposits to achieve a tightly stacked and dendrite‐free Zn deposition. Besides, the formed H2O‐deficient EDL structure enables the inorganic‐rich solid electrolyte interphase (SEI) with high Zn‐ion conductivity to inhibit the notorious parasitic reactions and improve the electrode reaction kinetics. Consequently, the Zn||Zn symmetric cells demonstrate an ultra‐long cycling life over 2700 cycles (the cumulative capacity reaches 5400 mA h cm−2) at a high current density of 50 mA cm−2. The Zn anodes show a high average Coulombic efficiency of 99.70% over 3650 cycles. The Zn||MnO2 full cells exhibit excellent practical‐level performance under cyclic continuous mode (3000‐cycle life at high rates) and cyclic intermittent mode (1170‐cycle life with 83.05% capacity retention). Practical pouch cells are also demonstrated with outstanding cycling performance. [ABSTRACT FROM AUTHOR]

High temperatures during a fire can lead to the evaporation of moisture and the degradation of hydration products within concrete, consequently compromising its mechanical properties. This paper thoroughly investigates the effect of fire-induced high temperatures on the residual load-bearing capacity of concrete structures, with a focus on prestressed concrete T-beams. By conducting constant temperature tests and residual load-bearing capacity tests, complemented by finite element modeling, this study examines the degradation of mechanical properties in prestressed concrete T-beams due to fire exposure and its impact on post-fire residual load-bearing capacity. Additionally, an equivalent concrete compressive strength method was employed to propose a calculation method for concrete material degradation under high temperatures and a corresponding concrete strength reduction factor. Simplified calculations were also performed for the high-temperature damage to reinforcement and prestressed tendons, leading to the derivation of a simplified formula for the residual load-bearing capacity of post-fire prestressed concrete T-beams. The results indicate that in prestressed concrete T-beams exposed to fire, an increase in holding time results in more severe damage modes, accelerated crack propagation, and wider crack widths during bending failure. Under the same load, a longer holding time corresponds to a more pronounced reduction in deflection. At holding times of 60 min, 120 min, and 180 min, the prestress losses were 48.17%, 85.16%, and 93.26%, respectively. The cracking load decreased by 15%, 27%, and 42%, while the residual load-bearing capacity decreased by 11%, 21%, and 28%. Comparison with experimental data demonstrates that both the finite element model and the simplified calculation formula exhibit high accuracy, offering a reliable reference for the performance evaluation of post-fire prestressed concrete T-beams. [ABSTRACT FROM AUTHOR]

The potential signal generated in the process of coal rock deformation and failure can better characterize the damage evolution process of coal rock, and has a good application prospect in the field of coal rock dynamic disaster monitoring and early warning. At present, most of the researches focus on the potential characteristics and laws of the same type of coal rock failure, and there is a lack of systematic research on the comparative analysis of potential characteristics of different types of coal rocks. At the same time, there are few comparative studies on the effect of different lithology coal rock structure failure process and components on the surface potential signal generation mechanism at the micro level. In order to deeply study the response law and difference of potential signal of coal and rock with different lithology, four kinds of samples, graphite, raw coal, sandstone and granite, are selected for uniaxial loading and the potential signals generated in the process of damage and failure are collected synchronously. The variation characteristics of potential signals of four samples under loading and failure are analyzed. The results show that the potential signal value of graphite sample is relatively low, and the potential signal fluctuates greatly during the crack damage and unstable crack propagation stages. The fluctuation of the potential signal of the raw coal sample is consistent with the fluctuation of the load, and the variation of the overall potential signal is relatively stable. The potential signal value of the sandstone sample increases rapidly in the compaction stage and the elastic deformation stage. The potential signal of the granite sample fluctuates greatly in the crack damage and unstable crack propagation stages, and the potential signal value increases faster. By scanning electron microscope and X-ray fluorescence spectrometer, the generation mechanism of potential signals of coal samples with different lithology is explained from the aspects of microstructure and components. The results show that there are more mylonic scratches from the microscopic point of view in the graphite and raw coal samples in the compaction and elastic deformation stages of coal rock loading, which indicates that the friction effect is the important reason for the electrification of the graphite and raw coal samples. The sandstone and granite samples contain more O and Si elements, and the piezoelectric effect is the key reason for the electrification of the sandstone and granite samples, and the potential signal of the sandstone sample is more affected by the piezoelectric effect. In the crack initiation and stable crack growth stage, crack damage and unstable crack propagation and unloading stage, the potential signal generation of each coal sample is mainly caused by the crack propagation and friction effect inside the sample. Among them, crack propagation is an important reason for the generation of coal-rock potential signals. The charge separation at the crack tip mainly includes three aspects, including electron escape caused by stress concentration at the crack tip, crack surface charge separation caused by crack propagation and crack tip discharge.

Binocular stereo vision relies on imaging disparity between two hemispherical retinas, which is essential to acquire image information in three dimensional environment. Therefore, retinomorphic electronics with structural and functional similarities to biological eyes are always highly desired to develop stereo vision perception system. In this work, a hemispherical optoelectronic memristor array based on Ag‐TiO2 nanoclusters/sodium alginate film is developed to realize binocular stereo vision. All‐optical modulation induced by plasmonic thermal effect and optical excitation in Ag‐TiO2 nanoclusters is exploited to realize in‐pixel image sensing and storage. Wide field of view (FOV) and spatial angle detection are experimentally demonstrated owing to the device arrangement and incident‐angle‐dependent characteristics in hemispherical geometry. Furthermore, depth perception and motion detection based on binocular disparity have been realized by constructing two retinomorphic memristive arrays. The results demonstrated in this work provide a promising strategy to develop all‐optically controlled memristor and promote the future development of binocular vision system with in‐sensor architecture. [ABSTRACT FROM AUTHOR]

In response to the requirements of national energy conservation and environmental protection, the establishment of green energy heating mine, it is proposed to eliminate the existing coal-fired boiler in 2# air shaft of Xiaobaodang Coal Mine and use the waste heat resources of the mine to solve the thermal insulation and anti-freezing of the wellhead of the air wellsite and the heat demand for building heating. Based on existing four technical routes of exhaust air waste heat utilization, through the comparative analysis of their technical characteristics, we finally proposed adopting direct cooling deep enthalpy exhaust air heat pump technology to solve the coal mine in hot demand, and introduced 2# well site general situation of Xiaobaodang Mine, wind heating demand and direct cooling deep enthalpy exhaust air heat pump system of technical route. Finally, we carried out the economic analysis, and completely solved the environmental protection problems caused by coal burning after the implementation of the project, and the existing waste heat of coal mine is recycled to reduce the waste of energy.

Previous research has shown that teacher–student relationships influence student engagement, which, in turn, plays a key role in academic achievement. However, few studies have focused on the mechanism between the teacher–student relationship and student engagement. To address this gap in the literature, this study examined the link between teacher–student relationships and college students' engagement via the mediator of peer relationships. The sample consisted of 222 university students in Southwest China. Results of structural equation modeling showed that a positive teacher–student relationship was positively related to student engagement, and peer relationships partially mediated this relationship. Our findings will help researchers and educators to better understand the mechanism of the link between teacher–student relationships and student engagement, and provide practical suggestions for improving college students' engagement. [ABSTRACT FROM AUTHOR]

The hole‐transporting material (HTM), poly (3,4‐ethylene dioxythiophene) poly(styrene sulfonate) (PEDOT : PSS), is the most widely used material in the realization of high‐efficiency organic solar cells (OSCs). However, the stability of PEDOT : PSS‐based OSCs is quite poor, arising from its strong acidity and hygroscopicity. In addition, PEDOT : PSS has an absorption in the infrared region and high highest occupied molecular orbital (HOMO) energy level, thus limiting the enhancement of short‐circuit current density (Jsc) and open‐circuit voltage (Voc), respectively. Herein, two asymmetric self‐assembled molecules (SAMs), namely BrCz and BrBACz, were designed and synthesized as HTM in binary OSCs based on the well‐known system of PM6 : Y6, PM6 : eC9, PM6 : L8‐BO, and D18 : eC9. Compared with BrCz, BrBACz shows larger dipole moment, deeper work function and lower surface energy. Moreover, BrBACz not only enhances photon harvesting in the active layer, but also minimizes voltage losses as well as improves interface charge extraction/ transport. Consequently, the PM6 : eC9‐based binary OSC using BrBACz as HTM exhibits a champion efficiency of 19.70 % with a remarkable Jsc of 29.20 mA cm−2 and a Voc of 0.856 V, which is a record efficiency for binary OSCs so far. In addition, the unencapsulated device maintains 95.0 % of its original efficiency after 1,000 hours of storage at air ambient, indicating excellent long‐term stability. [ABSTRACT FROM AUTHOR]