VMA: Divide-and-Conquer Vectorized Map Annotation System for Large-Scale Driving Scene

High-definition (HD) map serves as the essential infrastructure of autonomous driving. In this work, we build up a systematic vectorized map annotation framework (termed VMA) for efficiently generating HD map of large-scale driving scene. We design a divide-and-conquer annotation scheme to solve the spatial extensibility problem of HD map generation, and abstract map elements with a variety of geometric patterns as unified point sequence representation, which can be extended to most map elements in the driving scene. VMA is highly efficient and extensible, requiring negligible human effort, and flexible in terms of spatial scale and element type. We quantitatively and qualitatively validate the annotation performance on real-world urban and highway scenes, as well as NYC Planimetric Database. VMA can significantly improve map generation efficiency and require little human effort. On average VMA takes 160min for annotating a scene with a range of hundreds of meters, and reduces 52.3% of the human cost, showing great application value

Solvothermal synthesis and Curie temperature of monodispersed barium titanate nanoparticles

Barium titanate (BaTiO3) nanoparticles with various particle sizes were prepared by a solvothermal method X-ray powder diffraction (XRPD) patterns show that the as-prepared powders are of pure perovskite BaTiO3 Scanning electron microscopy (SEM) reveals that all the particles of BaTiO3 with different sizes are dispersed homogenously and have uniform size The room temperature and in situ high temperature XRD analyses indicate that both the proportion of the tetragonal phase and the Curie temperature of BaTiO3 Increase with increasing particles size The effects of the reaction parameters such as the concentration of reactants the polarity of solvent the reaction temperature and the amount of surfactant on the size morphology and uniformity of BaTiO3 nanoparticles are studied in detail (C) 2010 Elsevier B V All rights reservedNatural Science and Engineering Research Council of Canada (NSERC) ; National Natural Science Foundation of China [20725310, 91022020]; National Basic Research Program of China [2007CB815303

Room-temperature ferromagnetic/ferroelectric BiFeO3 synthesized by a self-catalyzed fast reaction process

Bismuth ferrite BiFeO3 has attracted a great deal of interest because of its multiferroic properties. However, BiFeO3 synthesized by conventional methods in the forms of single crystals, ceramics or thin films only exhibit ferroelectricity and antiferromagnetic order at room temperature, with weak ferromagnetism appearing at very low temperatures. To fully explore the potential of multiferroism in such applications as new memory devices, it is necessary to synthesize materials that show ferromagnetic order at room temperature as well, which will a priori allow for magnetoelectric coupling. In this paper, we report a new synthetic technique for the synthesis of BiFeO3 that exhibits unusual ferromagnetic properties. This method involves a low temperature fast solid state reaction based on tartaric acid. The mechanism of the reaction deduced from thermogravimetric analysis (TGA) and differential thermal analysis (TGA) suggests that a self-catalyzed process in the presence of iron and bismuth oxides triggers the oxidation of tartaric acid at low temperature and gives out a large amount of heat, which, in turn, leads to the formation of BiFeO3. The BiFeO3 synthesized in this way is ferromagnetic. The origin of the unusual ferromagnetism is supposed to be associated with point defects of oxygen vacancies generated during the self-catalyzed extremely fast exothermic reaction, which suppress the spin circular cycloid in BiFeO3. Ferroelectric hysteresis loops are displayed in the BiFeO3 samples. The presence of room temperature ferromagnetic and ferroelectric orders makes BiFeO3 a truly multiferroic material potentially interesting in such applications as magnetoelectric devices.Natural Science and Engineering Research Council of Canada (NSERC) ; National Natural Science Foundation of China [20725310, 20673085]; National Basic Research Program of China [2007CB815303

Polymorphic structures and properties of lead chromium phosphate Pb3Cr2(PO4)(4)

Single crystals of lead chromium phosphate Pb3Cr2(PO4)(4) were grown by a flux technique and characterized by X-ray powder and single crystal diffraction, differential thermal analysis, polarized light microscopy and magnetic measurements. Two polymorphic structures have been identified: a monoclinic Pb3Cr2(PO4)(4) of space group P2(1)/C (14) and a tetragonal Pb3Cr2(PO4)(4) of space group P4(1)2(1)2 (94), and their phase correlation is described. Both structures consist of a three-dimensional framework which is composed of PO4 tetrahedra and CrO6 octahedra connected via vertices. Lead ions are situated at the cavities of the framework, but the positions of lead ions in the monoclinic Pb3Cr2(PO4)(4) are different from those in the tetragonal Pb3Cr2(PO4)(4). The Pb3Cr2(PO4)(4) crystals are found to exhibit interesting physical properties. The ferroelastic domain structures reveal characteristic patterns of the tetragonal and the monoclinic symmetry of the crystals. The birefringence of the tetragonal crystals decreases with increasing temperature. The monoclinic crystal is found to undergo a series of magnetic phase transitions upon cooling, from a paramagnetic phase (from room temperature down), to an antiferromagnetic phase below T-N = 6K, and then to a weakly ferromagnetic phase below the Curie temperature T-C = 4 K, with a magnetic hysteresis loop displayed at 2 K.Natural Science and Engineering Research Council of Canada (NSERC) ; National Natural Science Foundation of China [20725310, 20673085]; National Basic Research Program of China [2007CB815303

Room-Temperature Weak Ferromagnetism Induced by Point Defects in alpha-Fe(2)O(3)

Natural Science and Engineering Research Council of Canada (NSERC); National Natural Science Foundation of China [20725310, 20673085]; National Basic Research Program of China [2007CB815303]Unusual room-temperature weak ferromagnetism alpha-Fe2O3 was prepared by heating the mixture of commercial alpha-Fe2O3 (as raw material) and tartaric acid at a mild temperature of 250 degrees C. This reaction involves a Fast heating and cooling process resulting from the self-catalyzed oxidation of tartaric acid. Careful chemical analyses confirmed that no any ferromagnetic impurities, such as Fe. Fe3O4, amorphous iron oxide and gamma-Fe2O3, were present in the treated sample. The unusual weak ferromagnetism was then attributed to the formation of a large amount of point defects in the treated sample during the peculiar synthetic process. Such a mechanism is supported by the result of annealing, which reduces the amount of point defects and thereby reestablishes the original antiferromagnetism in alpha-Fe2O3

A retrospective study of hepatitis B vaccination in preterm birth and low birth weight infants born to hepatitis B surface antigen-positive mothers: Time to close the policy-practice gap

National Immunization Program-version 2016 (ISIV-NIP-v2016) recommended a 4-dose hepatitis B vaccine (HepB) schedule for preterm birth (PTB) and low birth weight (LBW) infants born to HBsAg-positive mothers. However, the implementation of this immunization strategy in the past five years has not been fully evaluated in China. We reviewed the data of pregnant women and live-born infants from 24 hospitals between 2016 and 2021 in Lu’an, Anhui province, to estimate the prevalence of PTB, LBW, and hepatitis B virus (HBV) infected pregnant women. We analyzed the vaccination status of HepB and HBIG among PTB and LBW infants born to HBsAg-positive mothers. A total of 160 222 pregnant women and 159 613 live-born infants were included in this study. The estimated prevalence of PTB, LBW and HBV-infected pregnant women was 3.86% (range: 3.28%-5.10%), 2.77% (range: 2.12%-3.66%), and 3.27% (range: 3.03%-3.49%), respectively. We screened 340 PTB and LBW infants born to HBsAg-positive mothers between 2016 and 2020. We found that the coverage of HepB and HBIG among them was 100% and 99.39%. However, the timely vaccination rate of the HepB birth dose was only 78.59% and only four children (1.22%) received the 4-dose HepB as recommended by ISIV-NIP-v2016. The 4-dose of HepB for PTB and LBW infants born to HBsAg-positive mothers recommended by ISIV-NIP-v2016 was not fully implemented. A strong public health intervention should be taken to close the policy-practice gap in China in the future

Room-Temperature Weak Ferromagnetism Induced by Point Defects in alpha-Fe2O3

Unusual room-temperature weak ferromagnetism alpha-Fe2O3 was prepared by heating the mixture of commercial alpha-Fe2O3 (as raw material) and tartaric acid at a mild temperature of 250 degrees C. This reaction involves a Fast heating and cooling process resulting from the self-catalyzed oxidation of tartaric acid. Careful chemical analyses confirmed that no any ferromagnetic impurities, such as Fe. Fe3O4, amorphous iron oxide and gamma-Fe2O3, were present in the treated sample. The unusual weak ferromagnetism was then attributed to the formation of a large amount of point defects in the treated sample during the peculiar synthetic process. Such a mechanism is supported by the result of annealing, which reduces the amount of point defects and thereby reestablishes the original antiferromagnetism in alpha-Fe2O3.Natural Science and Engineering Research Council of Canada (NSERC) ; National Natural Science Foundation of China [20725310, 20673085]; National Basic Research Program of China [2007CB815303

Review on Detection and Analysis of Partial Discharge along Power Cables

Partial discharge (PD) detection and analysis plays a crucial role for acceptance testing and condition monitoring of power cables. Various aspects are related to PD in power cables from theory to practice. This paper first summarizes the PD mechanism and models used for PD analysis in power cables. Afterwards, PD detection is addressed in the aspects of off-line test, on-line test, and sensors. PD analysis is discussed in detail. Specifically, related quantities and algorithms for PD analysis are outlined. PD characteristics with affecting factors, e.g., dielectric type, load, and applied voltage are discussed. Experience on PD development trend with measurements in field is analyzed. Based on the comprehensive review, challenges of PD detection and analysis along a power cable are proposed

Low‐Cost Preparation of High‐Performance Na‐B‐H‐S Electrolyte for All‐Solid‐State Sodium‐Ion Batteries

Abstract All‐solid‐state sodium‐ion batteries have the potential to improve safety and mitigate the cost bottlenecks of the current lithium‐ion battery system if a high‐performance electrolyte with cost advantages can be easily synthesized. In this study, a one‐step dehydrogenation‐assisted strategy to synthesize the novel thio‐borohydride (Na‐B‐H‐S) electrolyte is proposed, in which both raw material cost and preparation temperature are significantly reduced. By using sodium borohydride (NaBH4) instead of B as a starting material, B atoms can be readily released from NaBH4 with much less energy and thus became more available to generate thio‐borohydride. The synthesized Na‐B‐H‐S (NaBH4/Na‐B‐S) electrolyte exhibits excellent compatibility with current cathode materials, including FeF3 (1.0–4.5 V), Na3V2(PO4)3 (2.0–4.0 V), and S (1.2–2.8 V). This novel Na‐B‐H‐S electrolyte will take a place in mainstream electrolytes because of its advantages in preparation, cost, and compatibility with various cathode materials

Upgrading the school entry vaccination record check strategy to improve varicella vaccination coverage: results from a quasi-experiment study

Background The school entry vaccination record check strategy (SECS) is an appropriate opportunity to recommend vaccines for students to improve vaccination coverage (VC). However, it is only utilized for providing necessary catch-up vaccination for students who are missing the Expanded Program on Immunization (EPI) vaccines in China. We aimed to address that gap and quantify the relationship between the SECS policy and the increase of coverage in varicella vaccine (VarV). Methods We employed a pretest and posttest quasi-experimental design to examine the effect of the upgraded SECS policy on the change of VarV coverage in newly enrolled students in Lu’an, 2019–2020. Results Eight hundred participants were randomly divided into the control group (C group, 31.8%), the telephone-based intervention group (T group, 31.2%), and the written notification intervention group (W group, 37.0%). Totally, 84 students received VarV during the study period, with a VC of 10.5%. The possibility of vaccination in the T group (RR = 4.9, 95% CI:2.2–10.9) and W group (RR = 5.2, 95% CI:2.4–11.5) was significantly higher than that in the C group (p< .001). Conclusions Our study demonstrates that the upgraded SECS produce a positive effect on improving the VC of VarV. This nudge strategy may decrease varicella outbreaks in schools in China, especially in provinces where VarV is not introduced into EPI