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In the e-commerce last-mile delivery process, the asset operators (logistics service providers who own parcel locker facilities) support their delivery service with parcel lockers, while the non-asset operators (logistics service providers without parcel lockers) perform door-to-door delivery. Due to demand fluctuation, asset operators' parcel-locker slots may be left vacant, while non-asset operators are stuck with the high-cost door-to-door service. The exclusiveness of parcel-locker usage reduces resource utilization and service efficiency in last-mile delivery. Therefore, this paper proposes a parcel-locker-sharing model in which these two parties share the parcel-locker capacity in last-mile delivery. The asset operator rents the unused parcel lockers to the non-asset operator by charging a rental fee,while the non-asset operator rents the parcel lockers for delivery to save logistics costs. The motivation of this alliance is to increase the profits of both parties and that of the total supply chain. This study establishes the supply-chain profit model for the parcel-locker-sharing framework and finds that the profit or loss depends on the comparison of the operation cost savings and delivery-cost savings. A numerical analysis is conducted to validate the final result. The research further suggests the optimal rental quantity and price interval. This paper is the first to study the operational mechanism of sharing the parcel locker between two distinct types of logistics service providers and to offer recommendations for industrial application. [ABSTRACT FROM AUTHOR]

The outstanding advantages of lightweight and flexibility enable flexible perovskite solar cells (PSCs) to have great application potential in mobile energy devices. Due to the low cost, low-temperature processibility, and high electron mobility, SnO2 nanocrystals have been widely employed as the electron transport layer in flexible PSCs. To prepare high-quality SnO2 layers, a monodispersed nanocrystal solution is normally used. However, the SnO2 nanocrystals can easily aggregate, especially after long periods of storage. Herein, we develop a green and cost-effective strategy for the synthesis of high-quality SnO2 nanocrystals at low temperatures by introducing small molecules of glycerol, obtaining a stable and well-dispersed SnO2-nanocrystal isopropanol dispersion successfully. Due to the enhanced dispersity and super wettability of this alcohol-based SnO2-nanocrystal solution, large-area smooth and dense SnO2 films are easily deposited on the plastic conductive substrate. Furthermore, this contributes to effective charge transfer and suppressed non-radiative recombination at the interface between the SnO2 and perovskite layers. As a result, a greatly enhanced power conversion efficiency (PCE) of 21.8% from 19.2% is achieved for small-area flexible PSCs. A large-area 5 cm × 5 cm flexible perovskite solar mini-module with a champion PCE of 16.5% and good stability is also demonstrated via this glycerol-modified SnO2-nanocrystal isopropanol dispersion approach. [ABSTRACT FROM AUTHOR]

Converting PbI2 residues into low‐dimensional perovskites through post‐treatment with ammonium‐based large cations can passivate 3D perovskites, thus has emerged as an effective strategy to improve the performance of perovskite solar cells (PSCs). Herein, a dramatically improved efficiency is demonstrated for PSCs based on a two‐step‐processed FAPbI3 perovskite via post‐treatment with formamidinium (FA)‐based benzamidine hydrochloride (PFACl), outperforming the commonly used methylamine (MA)‐based benzylamine hydrochloride (PMACl). With an in‐depth exploration of the crystal structures and morphology changes of the FAPbI3 perovskite upon the PFACl post‐treatment, the preferential formation of 1D rather than 2D structures on the 3D perovskite film is identified. In contrast to the 2D counterpart, the more energetically favorable 1D structure enables a more effective elimination of PbI2 residues. As a consequence, the PFACl‐induced 1D/3D perovskite film is endowed with smoother morphology, more uniform surface potential distribution, lower trap density, faster charge transfer, and better film stability than the PMACl‐induced 2D/3D perovskite and control films, demonstrating champion efficiencies of 24.9% for a small‐size PSC, 23.6% for a 1 cm2 large‐size PSC, and 21.2% for a 5 × 5 cm2 mini‐module, which is the highest among the perovskite solar mini‐modules using the two‐step deposition method. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this study was to assess abnormal eye movement signs during different periods, namely, ictal periods and symptom-free intervals, in patients with vestibular migraine.Patients and Methods: We assessed oculomotor signs using videonystagmography in 90 patients with VM (40 during ictal periods and 50 during symptom-free intervals) according to validated diagnostic criteria.Results: Abnormal saccades, smooth pursuit and optokinetic test results; spontaneous nystagmus; and positional nystagmus were all observed in vestibular migraine patients, and there was no significant difference between different periods. Positional nystagmus was the most common in both the ictal and asymptomatic periods (60% and 36%, respectively). Positional nystagmus was induced in a variety of positions during both periods, and the slow-phase velocity ranged from < 2 to 10°/s. The duration of positional nystagmus was over 60s in most cases. Overall, central oculomotor dysfunctions occurred in 27.5% of patients during VM attacks and 4% of patients during symptom-free intervals; this difference was statistically significant (p = 0.002).Conclusion: In patients with VM, abnormal oculomotor signs can be found during both vertigo attacks and asymptomatic intervals. Positional nystagmus is the most common of these abnormalities and can be induced in different positions. The amplitude of these patients' positional nystagmus tends to be low, and the duration tends to be long. Observing changes in eye movements by videonystagmography may be helpful in the diagnosis of VM. [ABSTRACT FROM AUTHOR]