Sustainable Layout Planning Methods for Taxi Service Centres: A Case Study of Jiangning District, Nanjing

Taxi fleet size has undergone a continuous rapid growth in Chinese cities, while the service facility layout planning has relatively lagged behind, causing a decrease in the service quality. Therefore, it is crucial to carry out taxi service centre layout planning. This study analyses the functional orientation and hierarchical layout mode of taxi service centres, and then proposes stepwise layout planning methods combining existing transportation facilities. Considering the demand for integrated service centres is relatively low and convenient service centres are highly flexible, their layout can be determined by qualitative analysis. The constrained layout model of functional service centres is established by optimizing the layout scheme among various alternative taxi service centres. The study finds the model is a mixed 0–1 integer programming problem, genetic algorithms are applied to solve it. Finally, the proposed methods are applied to a real case of Jiangning district, Nanjing. The results show that one integrated service centre, four functional service centres, and twenty-three convenient service centres could satisfy taxi drivers’ demand, which suggests that the proposed methods should effectively address the layout planning problem of taxi service centres, thus have important implications for other cities’ downtown areas in China and beyond

Electronic anisotropy in magic-angle twisted trilayer graphene

Due to its potential connection with nematicity, electronic anisotropy has been the subject of intense research effort on a wide variety of material platforms. The emergence of spatial anisotropy not only offers a characterization of material properties of metallic phases, which cannot be accessed via conventional transport techniques, but it also provides a unique window into the interplay between Coulomb interaction and broken symmetry underlying the electronic order. In this work, we utilize a new scheme of angle-resolved transport measurement (ARTM) to characterize electron anisotropy in magic-angle twisted trilayer graphene. By analyzing the dependence of spatial anisotropy on moir\'e band filling, temperature and twist angle, we establish the first experimental link between electron anisotropy and the cascade phenomenon, where Coulomb interaction drives a number of isospin transitions near commensurate band fillings. Furthermore, we report the coexistence between electron anisotropy and a novel electronic order that breaks both parity and time reversal symmetry. Combined, the link between electron anisotropy, cascade phenomenon and PT-symmetry breaking sheds new light onto the nature of electronic order in magic-angle graphene moir\'e systems.Comment: Main text 7 pages, 5 figures. Total 17 pages, 15 figures. arXiv admin note: text overlap with arXiv:2209.1296

Momentum-polarized superconductivity in twisted trilayer graphene

The spin-configuration of a Cooper pair is often informative of the pairing symmetry. According to the BCS theory, a conventional, s-wave superconductor arises from Cooper pairing in the singlet channel. Whereas a triplet Cooper pair is directly linked to a spatial wavefunction in the p- or f-wave channel, a hallmark of unconventional superconductivity. In multilayer graphene, the nature of the pairing instability is further complicated by emergent orders in the momentum-space, such as valley and momentum polarization. The presence of momentum-space instability suggests that the spin channel alone is insufficient to describe the superconducting pairing symmetry. In this work, we use angle-resolved nonreciprocal transport measurement to investigate the influence of momentum-space instabilities. We uncover a new cascade phenomenon across the moir\'e band fillings, where a series of transitions between momentum-polarized states appear outside the regular sequence of Dirac revivals. Moreover, we identify a new aspect of superconductivity, which is defined by its coexistence with spontaneous momentum polarization. Our findings point towards a direct link between spontaneously broken rotational and time-reversal symmetries, which has intriguing implications on the nature of the pairing instability.Comment: Main text pages 1-7, 4 figures. Method pages 8-11, 5 figures. SI page 12-22, 15 figure

Deciphering decadal observation of Fukushima-derived radiocesium in the most polluted port near the Fukushima Daiichi Nuclear Power Plant: from seawater to marine fish

The biological concentration effect of radionuclides in marine fish has exacerbated public anxiety about seafood security in the context of Fukushima nuclear-contaminated water discharged into the ocean. However, the most polluted port near the Fukushima Daiichi Nuclear Power Plant (FDNPP) has seldom been investigated, especially for radioactivity in marine fish. In this study, decadal observations of radiocesium in marine fish and seawater from the most polluted port were simultaneously established after the Fukushima Nuclear Accident. We found a generally decreasing trend of historical 137Cs activity in seawater, with seasonal variations modulated by precipitation. Seasonal variations were elucidated with finer detail and divided into exponential decline in the dry season and steady variation in the wet season. A novel method was proposed to estimate the continuing source term of 137Cs derived from the FDNPP, which was 3.9 PBq in 2011 and 19.3 TBq between 2012 and 2022 on the basis of historical 137Cs. The biological concentration effect of marine fish is quantitatively emphasized according to the higher ratio of over-standards for radiocesium in marine fish relative to that in seawater. Long-term observation and analysis of radiocesium in marine fish and seawater from the most polluted port would provide insights into the scientific evaluation of the effectiveness of the decommissioning of the FDNPP in the past and share lessons on the fate of Fukushima-derived radionuclides in the future

Visual identification and pose estimation algorithm of nut tightening robot system

Abstract To realize the automatic tightening of nuts, a nut tightening robot system strategy based on machine vision was designed in this work. The strategy was based on three stages: nut image calibration, nut identification and nut pose estimation. In the first stage, the template pose image of the nut and the coordinates of the nut center in this nut image were obtained by calibration. In the second stage, a nut identification algorithm based on improved the backbone feature extraction network and area generation network of Faster-RCNN was presented, which improved the efficiency and accuracy of nut identification. In the last stage, a nut pose estimation algorithm based on Fourier and log-polar coordinate transformation was presented to solve the rotation angle, translation and scale of the nut relative to the template nut image, and then obtain the rotation angle of the sleeve and the central coordinate of the nut. An experimental nut tightening robot platform was also set up in this work. The results of 50 tests showed that the proposed detection methods could identify nuts with 100% accuracy, and with this proposed pose estimation methods the average error of the rotation angle of the nut was 0.057, the average error of the center position of the nut in and directions was and of direction was . The experimental results showed that the nut tightening robot scheme and algorithm designed in this work were feasible in nut identification and pose estimation, and met the requirements of insertion accuracy in the process of nut tightening.</jats:p

Research on Assembly Method of Threaded Fasteners Based on Visual and Force Information

Threaded fastening operations are widely used in assembly and are typically time-consuming and costly. In low-volume, high-value manufacturing, fastening operations are carried out manually by skilled workers. The existing approaches are found to be less flexible and robust for performing assembly in a less structured industrial environment. This paper introduces a novel algorithm for detecting the position and orientation of threaded holes and a new method for tightening bolts. First, the elliptic arc fitting method and the three-point method are used to estimate the initial position and orientation of the threaded hole, and the force impact caused by switching from the free space to the constrained space during bolt tightening is solved. Second, by monitoring the deformation of passive compliance, the position information is introduced into the control process to better control the radial force between the bolt and the threaded hole in the tightening process. The constant force controller and orientation compliance controller are designed according to the adaptive control theory. A series of experiments are carried out. The results show that the proposed method can estimate the initial position and orientation of an M24 bolt with an average position error of 0.36 mm, 0.43 mm and 0.46 mm and an orientation error of 0.65°, 0.46° and 0.59°, and it can tighten the bolt with a success rate of 98.5%

The complete mitochondrial genome of ribbed gunnel Dictyosoma burgeri (van der Hoeven, 1855)

The complete mitochondrial genome of Dictyosoma burgeri collected from Yellow and Bohai Seas was determined by next-generation sequencing. The mitogenome is a circular molecule 16,513 bp in length, including the typical structure of 13 protein-coding genes, 2 ribosomal RNA genes, 22 transfer RNA genes, and a control region. The TAS, central CSB, and CSB were detected in the control region. The gene contents of the mitogenome are identical to those observed in most bony fishes

Analysing Urban Tourism Accessibility Using Real-Time Travel Data: A Case Study in Nanjing, China

This study aimed to evaluate the spatial accessibility of tourism attractions in the urban destination city. An analytical framework for assessing urban tourism accessibility at different spatial scales was proposed to provide references on the interaction of urban transport and tourism systems. In addition to the travel time-based measure, a modified gravity model integrating the tourism destination attractiveness, urban transport system characteristics, and tourist demand distribution was developed to evaluate tourism accessibility in this study. Real-time travel data obtained from the Web Maps service were used to take the actual road network operation conditions into consideration and improve the accuracy of estimation results. Taking Nanjing as an example, the analysis results revealed the spatial heterogeneity of tourism accessibility and inequality in tourism resource availability at different levels. Road transport service improvement plays a dominant role in increasing tourism accessibility in areas with insufficient tourism resources, such as the outskirts of the destination city. As for areas with abundant attractions, authorities could pay attention to destination attractiveness construction and demand management in addition to the organization and management of road network operations around attractions during holidays. The results of this study provide a potentially valuable source of information for urban tourism destination management and transport management departments

Inhaled RNA Therapeutics for Obstructive Airway Diseases: Recent Advances and Future Prospects

Obstructive airway diseases, e.g., chronic obstructive pulmonary disease (COPD) and asthma, represent leading causes of morbidity and mortality worldwide. However, the efficacy of currently available inhaled therapeutics is not sufficient for arresting disease progression and decreasing mortality, hence providing an urgent need for development of novel therapeutics. Local delivery to the airways via inhalation is promising for novel drugs, because it allows for delivery directly to the target site of action and minimizes systemic drug exposure. In addition, novel drug modalities like RNA therapeutics provide entirely new opportunities for highly specific treatment of airway diseases. Here, we review state of the art of conventional inhaled drugs used for the treatment of COPD and asthma with focus on quality attributes of inhaled medicines, and we outline the therapeutic potential and safety of novel drugs. Subsequently, we present recent advances in manufacturing of thermostable solid dosage forms for pulmonary administration, important quality attributes of inhalable dry powder formulations, and obstacles for the translation of inhalable solid dosage forms to the clinic. Delivery challenges for inhaled RNA therapeutics and delivery technologies used to overcome them are also discussed. Finally, we present future prospects of novel inhaled RNA-based therapeutics for treatment of obstructive airways diseases, and highlight major knowledge gaps, which require further investigation to advance RNA-based medicine towards the bedside.</jats:p