Abstract To study the bond performance between fiber-reinforced seawater sea-sand concrete and corrosion-resistant rebars (glass fiber–reinforced polymer [GFRP] bars and epoxy resin–coated rebars) in extremely hot and humid marine environments, bond anchorage tests between reinforcement and seawater sea-sand concrete are conducted to study bond performance. The failure morphology of reinforced concrete was investigated, and the bond-slip curves of different types of rebar and concrete were compared. According to the research results, the addition of basalt and polypropylene fibers to seawater sea-sand concrete changed the distribution of bonding stress, which was conducive to an improvement in the anchorage efficiency of reinforcement and concrete. The chemical bonding performance between the fiber-reinforced seawater sea-sand concrete and rebar is improved, wherein the bond stress increases by 94.01 % at the beginning of the slip, and the residual bond stress increases by 91.72 %. Compared with ordinary seawater sea-sand concrete, the bonding strength between ordinary reinforced rebar and fiber-reinforced seawater sea-sand concrete increased by 20.75 %, and the bonding strength between the GFRP bar and fiber-reinforced concrete decreased by 15.37 %. Based on the friction mechanism of rebars and concrete, bonding strength models of ordinary rebar, epoxy resin–coated rebar, and GFRP bars with fiber-reinforced seawater sea-sand concrete are presented.
Large code models (LCMs) have remarkably advanced the field of code intelligence. Despite their impressive capabilities, they still face practical employment challenges, such as high costs, limited accessibility of proprietary LCMs, and adaptability issues of ultra-large LCMs. These challenges highlight the critical need for more accessible, lightweight yet effective LCMs. In this paper, we propose IterKD, an Iter Knowledge Distillation framework, which aims at continually transferring the programming capabilities of larger, advanced LCMs (Teacher) to smaller, less powerful LCMs (Student). IterKD consists of three stages in one cycle: (1) Correct-and-Fault Knowledge Delivery stage aims at improving the student models capability to recognize errors while ensuring its basic programming skill during the knowledge transferring, which involves correctness-aware supervised learning and fault-aware contrastive learning methods. (2) Multi-view Feedback stage aims at measuring the quality of results generated by the student model from two views, including model-based and static tool-based measurement; (3) Feedback-based Knowledge Update stage aims at updating the student model adaptively by generating new questions at different difficulty levels, in which the difficulty levels are categorized based on the feedback in the last stage. By performing the training cycle iteratively, the student model is continuously refined through learning more advanced programming skills from the teacher model. Finally, based on the proposed IterKD framework, we develop a lightweight yet effective LCM, named IterCoder, which is built upon CodeLlama-7B. Experimental results show that IterCoder achieves a Pass@1 score of 65.2 on the HumanEval benchmark, outperforming over-30B-sized LCMs by an average of 47.51% and surpassing comparable-sized LCMs by an average of 118.47%.
Multicompartment nanoparticles (MCBNs) constructed with the brush block terpolymer of [poly(p-chloromethylstyrene)-graft-poly(4-vinylpyridine)]-block-polystyrene (PCMS-g-P4VP)-b-PS are prepared through dispersion polymerization of styrene in the methanol/water mixture mediated by the brush macro-RAFT agent of poly(p-chloromethylstyrene)-graft-poly(4-vinylpyridine) trithiocarbonate. During the dispersion RAFT polymerization, the molecular weight of the brush (PCMS-g-P4VP)-b-PS block terpolymer linearly increases with the monomer conversion. Ascribed to the brush (PCMS-g-P4VP) block, MCBNs including a PS core and discrete subdomains of (PCMS-g-P4VP) on the PS core dispersed in water are formed. The reasons leading to formation of MCBNs are discussed, and the immiscibility of the brush (PCMS-g-P4VP) block with the PS core, the low number density of the brush (PCMS-g-P4VP25)21 chains tethered on per surface area of the PS core, and the high molecular weight but the low polymerization degree of the brush (PCMS-g-P4VP) block are ascribed. Au nanoparticles are immobilized on the bulgy PCMS-g-P4VP subdomains on MCBNs and show high catalytic efficiency in the aerobic alcohol oxidation.
Foamed lightweight soil is widely used in the reconstruction, with the rapid development of China’s economy, it is also widely used in road engineering. Besides, foamed lightweight soil has good mechanical properties, which can effectively reduce the project cost. In this paper, based on Shanxi loess, the mechanical properties of foamed lightweight soil with loess matrix are studied, and a mixture ratio of foamed lightweight soil is given. The compressive strength of the foamed lightweight soil increases rapidly, while the tensile strength increases slowly. The foamed lightweight soil should be added to improve the tensile strength of materials (such as reinforcement) in the road reconstruction and expansion. The strength of foamed lightweight soil is greatly affected by curing time, and the stronger the curing, the faster the strength increases. This research results can provide some reference for the reconstruction and expansion of loess road engineering.
A doubly thermo-responsive schizophrenic diblock copolymer, poly(tert-butyl methacrylate)-block-poly[N-(4-vinylbenzyl)-N,N-diethylamine], was synthesized and its flip-flop micellization was demonstrated.
A new multi-stimuli-responsive homopolymer of poly[N-[2-(diethylamino)ethyl]acrylamide] (PDEAEAM), which combines the thermoresponsive and pH/CO2-responsive moieties of the diethylamino and acrylamide groups, was proposed and synthesized by RAFT polymerization. Well-defined PDEAEAM was synthesized by solution RAFT polymerization as indicated by the linear increase in the polymer molecular weight with the monomer conversion and the narrow molecular weight distribution. The appending diethylamino group in the polymer backbone was found to be crucial to determine the thermoresponse of PDEAEAM in water. The parameters including the polymerization degree, the polymer concentration, the deuterated solvent, the terminal attached on the polymer backbone, the additives of salt and urea, and pH and bubbling CO2 affecting the thermoresponse of PDEAEAM in aqueous solution at the lower critical solution temperature (LCST) were investigated. The temperature-variable 1H NMR analysis suggests that the dehydration of PDEAEAM at temperature above LCST is ascribed to the weakened hydrogen bonding between the CONHCH2 and/or (CH2N(CH2CH3)2) moieties with the solvent of water. The proposed multi-stimuli-responsive homopolymer of PDEAEAM has two advantages of (1) the convenient and controllable RAFT synthesis and (2) the pH/CO2 tunable LCST at ∼36 °C being very close to body temperature.
Polymerization-induced self-assembly (PISA) is proven to be a powerful approach of in situ synthesis of block copolymer (BCP) nanoassemblies, and polymerization conditions are found to be correlative to the block copolymer morphology. In this study, three PISA formulations, e.g., the poly(ethylene glycol) macro-RAFT agent mediated dispersion RAFT polymerization, seeded dispersion RAFT polymerization, and seeded emulsion RAFT polymerization, are comparatively investigated. Our results reveal that dispersion RAFT polymerization undergoes much slower than other two PISA formulations of seeded dispersion RAFT polymerization and seeded emulsion RAFT polymerization. Besides, the results reveal that the BCP morphology of poly(ethylene glycol)-block-polystyrene (PEG45-b-PS) produced via three PISA cases is much different. That is, dispersion RAFT polymerization affords vesicles, seeded dispersion RAFT polymerization affords the mixture of vesicles and porous nanospheres, and seeded emulsion RAFT polymerization affords porous nanospheres of PEG45-b-PS. The reason for formation of porous nanospheres by seeded RAFT polymerization is discussed, and the fed styrene monomer swelling the seeded vesicles is ascribed. Our study clarifies how the PISA procedures affect the morphology of BCP nanoassemblies, and it is expected to be effective to prepare BCP nanoassemblies with interesting morphology.
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