Prestressed Concrete Cylinder Pipe (PCCP) is a composite pipe structure commonly subjected to earth pressure, internal pressure, and ground loads. To confirm the bearing capacity of PCCP by using the ...in-direct design method, one of the most important experiments is the Three-Edge Bearing (TEB) test. A rational theoretical analysis method and Finite Element Analysis (FEA) are developed in this study because the TEB test is costly and difficult to conduct. The proposed theoretical analysis method and Finite Element (FE) method can be used to calculate the internal force, the displacement, the cracking load, and the bearing capacity of PCCP under the TEB load. In addition, a parametric study is carried out by using the validated theoretical analysis and FEA method. It is found that the concrete strength, the prestressing level, and the radius-to-thickness ratio of the steel cylinder affects the bearing capacity of PCCP under the TEB load. Furthermore, the proposed theoretical analysis method can be used to calculate the bearing capacity of other kinds of rigid pipes under the three-edge bearing load.
N-doped porous carbon materials (NPCs) were prepared by the carbonization of covalent-organic frameworks as precursors and used as anodes for lithium and sodium ion batteries (LIBs and SIBs) for the ...first time. The morphology, structure and electrochemical performance were characterized and evaluated by field emission scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, Raman spectroscopy, X-ray diffraction, nitrogen adsorption and desorption isotherms, galvanostatic charge/discharge tests, cyclic voltammetry and electrochemical impedance spectroscopy, respectively. The NPCs not only show high maximum reversible charge capacities of 488 mAh g−1 at 100 mA g−1 (LIBs) and 237.7 mAh g−1 at 50 mA g−1 (SIBs) after 100 cycles, but also deliver high reversible charge capacities of 143 mAh g−1 at 5 A g−1 (LIBs) and 88.8 mAh g−1 at 2.5 A g−1 (SIBs) and excellent rate performance. Moreover, superior long-life cycling stability is observed for 5000 cycles even at a very high current density of 5 A g−1 for LIBs and 2.5 A g−1 for SIBs. The excellent electrochemical performance of NPCs with superior reversible capacity, good rate performance, and long-life cycling stability is attributed to their N doping, high specific surface area and porous structure with large interlayer distance.
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Squaric-acid-linked zwitterionic covalent organic frameworks (Z-COFs), assembled through interlayer interactions, are emerging as potential materials in the field of photocatalysis. However, the ...study of their interlayer interactions has been largely overlooked. To address this, this work systematically calculated interlayer interactions via density functional theory (DFT) and analyzed the differences in interlayer interactions of different structures of Z-COFs through interlayer slippage, planarity, and an independent gradient model based on the Hirshfeld partition (IGMH). Furthermore, it revealed the relationship between the interactions and the macroscopic photocatalytic carrier transport performance of the material. The results indicated that both preventing interlayer slippage and enhancing planarity can enhance the interlayer interactions of Z-COFs, thereby improving their macroscopic carrier transport performance in photocatalysis.
Inspired by the repair of DNA through efficient reformation of hydrogen bonds (H-bonds), herein we report a facile one-step approach to construction of self-healing antifogging thin films on the ...basis of partly cross-linked poly(vinyl alcohol)(PVA) and poly(acrylic acid)(PAA). By designing the molar ratio of hydroxyl groups to carboxyl groups, the cross-linked polymer thin films maintain abundant free hydroxyl groups to present excellent antifogging property, which is derived from the hydrophilicity and hygroscopicity of the thin films. The thin films showed smart intrinsic self-healing characteristics towards wounds caused by external forces, which is attributed to sufficient free hydroxyl groups at the scratched interfaces to reform H-bonds across the interfaces and a sufficient chain mobility that is indispensable for chain diffusion across the interfaces and hydroxyl groups association to form H-bonds. No synthetic surfaces reported so far possess all the unique characteristics of the polymer thin films: intrinsic self-healing, long-term antifogging, excellent mechanical property, high transmittance and large-scale feasibility.
A diketopyrrolopyrrole‐based conjugated polymer, PDPP‐4FTVT, which exhibits ambipolar transport behavior in air with hole and electron mobilities up to 3.40 and 5.86 cm2 V−1 s−1, respectively, is ...synthesized via direct arylation polycondensation. Incorporation of F‐atoms in β‐positions of thiophene rings dramatically improves the efficiency of direct arylation polycondensation.
Proteins such as FUS phase separate to form liquid-like condensates that can harden into less dynamic structures. However, how these properties emerge from the collective interactions of many amino ...acids remains largely unknown. Here, we use extensive mutagenesis to identify a sequence-encoded molecular grammar underlying the driving forces of phase separation of proteins in the FUS family and test aspects of this grammar in cells. Phase separation is primarily governed by multivalent interactions among tyrosine residues from prion-like domains and arginine residues from RNA-binding domains, which are modulated by negatively charged residues. Glycine residues enhance the fluidity, whereas glutamine and serine residues promote hardening. We develop a model to show that the measured saturation concentrations of phase separation are inversely proportional to the product of the numbers of arginine and tyrosine residues. These results suggest it is possible to predict phase-separation properties based on amino acid sequences.
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•Phase separation of FUS requires both the N-terminal PLD and the C-terminal RBD•Tyrosine and arginine govern the saturation concentration of phase separation•Glycine maintains liquidity, whereas glutamine and serine promote hardening•An associative polymer model predicts the phase behavior of FUS family proteins
The phase-separation behavior of FUS family proteins can be predicted by the prevalence and position of specific amino acids.
Rational fabrication and structure design of anode materials with high specific capacity and excellent cycling stability are of significant importance for the development of high-performance ...lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs). In this paper, a zeolitic imidazolate framework-8 (ZIF-8) with a unique polyhedral morphology and large size (about 2 μm) was successfully synthesized through a facile co-precipitation method. After successive carbonization and sulfidation, ZnS nanoparticles decorated on nitrogen-doped porous carbon polyhedra (ZnS/NPC) were obtained. When applied as the anode material for LIBs, the ZnS/NPC hybrid displays the highest reversible specific capacity for ZnS-based electrodes reported so far (1067.4 mA h g −1 at 0.1 A g −1 after 200 cycles), excellent rate capability (364.6 mA h g −1 at 4 A g −1 ), and robust long-term cycling performance (856.8 mA h g −1 at 1 A g −1 after 1000 cycles). As for SIBs, the resultant ZnS/NPC also exhibits a desirable capacity of 370.6 mA h g −1 after 100 cycles at 0.1 A g −1 and 289.2 mA h g −1 after 1000 cycles at 1 A g −1 . Such superior lithium and sodium storage performances should be attributed to the distinctive structure advantages inherited from ZIF-8, where the Zn ions were in situ converted to ZnS with high reactivity upon electrochemical cycling and the organic linkers were pyrolyzed to nitrogen-doped porous carbon polyhedra to enhance the conductivity of the hybrid and keep the structure stability during cycling.
Aiming at the life data information of multiple types of testing sources for the same product, a mixed base distribution constructed to achieve three-source data fusion, and at the same time, the ...overall distribution density function of the life data source was estimated. And the iterative formula of the maximum likelihood estimation of each unknown parameter in the parameter vectors of the mixed basis distribution density function was obtained based on the EM algorithm. At the same time, the estimated value of each parameter was given by using the sample weighted by Bootstrap method, the density function analysis of the mixed basis distribution was determined, and the product reliability analysis was completed. The calculation example verified the feasibility and effectiveness of this type of model.
Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disorder involving both upper motor neurons (UMN) and lower motor neurons (LMN). Enormous research has been done in the past few ...decades in unveiling the genetics of ALS, successfully identifying at least fifteen candidate genes associated with familial and sporadic ALS. Numerous studies attempting to define the pathogenesis of ALS have identified several plausible determinants and molecular pathways leading to motor neuron degeneration, which include oxidative stress, glutamate excitotoxicity, apoptosis, abnormal neurofilament function, protein misfolding and subsequent aggregation, impairment of RNA processing, defects in axonal transport, changes in endosomal trafficking, increased inflammation, and mitochondrial dysfunction. This review is to update the recent discoveries in genetics of ALS, which may provide insight information to help us better understanding of the disease neuropathogenesis.
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