Approximation of circular arcs by Bézier curves

AbstractFor the circular arc of angle 0<α<π we present the explicit form of the best GC3 quartic approximation and the best GC2 quartic approximations of various types, and give the explicit form of the Hausdorff distance between the circular arc and the approximate Bézier curves for each case. We also show the existence of the GC4 quintic approximations to the arc, and find the explicit form of the best GC3 quintic approximation in certain constraints and their distances from the arc. All approximations we construct in this paper have the optimal order of approximation, twice of the degree of approximate Bézier curves

Dual additives (lithium nitrate, lithium difluoro(bisoxalato)phosphate) to improve the electrochemical performance of Ni-rich cathode coupled with ultra-thin lithium metal anode

Department of Energy Engineering (Battery Science and Technology)Ni-rich layered oxide cathode (Ni> 80%) and lithium metal anode are strong candidates for high energy density batteries. However, the commercialization is limited due to the morphological instability of the Ni-rich cathode, low coulombic efficiency of lithium metal, and vertical growth of dendrites. Herein, we minimize the distance between the cathode and the anode to increase limit current density and add a dual additive to form a stable solid electrolyte interphase (SEI) layer on the anode and cathode surface. Concentrated ether-based electrolytes containing lithium nitrate (LiNO3) and lithium difluoro (bisoxalato) phosphate (LiDFBP) improves the capacity retention (80%) in a 20 ??m Li|LiNi0.8Co0.1Mn0.1O2 full cell, with a high Coulombic efficiency of 99.5% after 245 cycles at 0.9 C rate. This paper, which improves the battery performance through optimization of cell structure (distance between electrodes) and stabilization of the interface, is expected to help in various lithium metal battery research in the future.clos

Size distributions of atmospheric particulate matter and associated trace metals in the multi-industrial city of Ulsan, Korea

Particulate matter (PM) was collected using micro-orifice uniform deposit impactors from a residential (RES) site and an industrial (IND) site in Ulsan, South Korea, in September-October 2014. The PM samples were measured based on their size distributions (11 stages), ranging from 0.06 ??m to over 18.0 ??m. Nine trace metals (As, Se, Cr, V, Cd, Pb, Ba, Sb, and Zn) associated with PM were analyzed. The PM samples exhibited weak bimodal distributions irrespective of sampling sites and events, and the mean concentrations of total PM (TPM) measured at the IND site (56.7 ??g/m3) was higher than that measured at the RES site (38.2 ??g/m3). The IND site also showed higher levels of nine trace metals, reflecting the influence of industrial activities and traffic emissions. At both sites, four trace metals (Ba, Zn, V, and Cr) contributed to over 80% of the total concentrations in TPM. The modality of individual trace metals was not strong except for Zn; however, the nine trace metals in PM2.5 and PM10 accounted for approximately 50% and 90% of the total concentrations in TPM, respectively. This result indicates that the size distributions of PM and trace metals are important to understand how respirable PM affects public health

Fast track fed-batch culture development for COVID-19 vaccine clinical study

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Retrieval of NO2 Column Amounts from Ground-Based Hyperspectral Imaging Sensor Measurements

Total column amounts of NO2 (TCN) were estimated from ground-based hyperspectral imaging sensor (HIS) measurements in a polluted urban area (Seoul, Korea) by applying the radiance ratio fitting method with five wavelength pairs from 400 to 460 nm. We quantified the uncertainty of the retrieved TCN based on several factors. The estimated TCN uncertainty was up to 0.09 Dobson unit (DU), equivalent to 2.687 ?? 1020 molecules m???2) given a 1?? error for the observation geometries, including the solar zenith angle, viewing zenith angle, and relative azimuth angle. About 0.1 DU (6.8%) was estimated for an aerosol optical depth (AOD) uncertainty of 0.01. In addition, the uncertainty due to the NO2 vertical profile was 14% to 22%. Compared with the co-located Pandora spectrophotometer measurements, the HIS captured the temporal variation of the TCN during the intensive observation period. The correlation between the TCN from the HIS and Pandora also showed good agreement, with a slight positive bias (bias: 0.6 DU, root mean square error: 0.7 DU)