An Improved Discharge Profile-based DC-link Capacitance Estimation for Traction Inverter in Electric Vehicle Applications

DC-link capacitor is an important part of traction inverters in electric vehicles (EVs), contributing to cost, size, and failure rate on a considerable scale. This paper proposes a non-invasive DC-link capacitance estimation method based on the capacitor discharge profile during the turning-off transition of a traction inverter. The proposed method relies on the existing control and measurement of the traction inverter without the need for software modifications and hardware updates. It minimizes the new risks introduced into the system operation because the estimation procedure is implemented after vehicles are parked. A novel correction solution is proposed to secure the estimation accuracy while also reducing the sampling requirements. Compared with conventional estimation methods, the proposed scheme outperforms in complexity and accuracy. The proof-of-concept experiments based on a scaled-down inverter prototype and a full-scale traction inverter for EV applications verify the feasibility of the proposed method.<br/

3,6-Dibromo-7-ethyl­amino-4-methyl-2H-chromen-2-one

In title compound, C12H11Br2NO2, the coumarin ring system is almost planar, the two rings being inclined to one another by 1.40 (15)°. There are two short intra­molecular inter­actions (N—H⋯Br and C—H⋯Br) involving the Br atoms. In the crystal, mol­ecules stack along the a-axis direction via π–π inter­actions; the centroid–centroid distances vary from 3.6484 (19) to 3.7942 (19) Å

Publication trends of primary angle-closure disease during 1991-2022: a bibliometric analysis

AIM: To perform a bibliometric analysis in the field of primary angle-closure disease (PACD) research to characterize current global trends and compare contributions from different countries, institutions, journals, and authors. METHODS: All PACD-related publications from 1991 to 2022 from the Web of Science Core Collection database were extracted. Microsoft Excel and VOSviewer were used to collect publication data, analyze publication trends, and visualize relevant results. RESULTS: A total of 1721 publications with 34 591 citations were identified. China produced the most publications (554) while ranking third in citations (8220 times). The United States contributed the most citations (12 315 times) with publications (362) ranking second. The Investigative Ophthalmology Visual Science was the most productive journal concerning PACD, and Aung Tin was the author with the highest number of publications in the field. Keywords were classified into three clusters, epidemiology and pathogenesis research, optical coherence tomography (OCT) and other imaging examinations, and glaucoma surgery treatment. Genome-wide association, susceptibility loci, OCT, and combined phacoemulsification have become new hot research topics in recent years since 2015. CONCLUSION: China, the United States, and Singapore make the most outstanding contributions in the field of PACD research. OCT, combined phacoemulsification, and gene mutation-related study, are considered the potential focus for future research

The First Photometric and Orbital Period Investigation of an Extremely Low Mass Ratio Contact Binary with a Sudden Period Change, TYC 4002-2628-1

Photometric observations for the totally eclipsing binary system TYC 4002-2628-1, were obtained between November 2020 and November 2021. To determine the stellar atmospheric parameters, a spectral image was taken with the 2.16 m telescope at National Astronomical Observatory of China (NAOC). TYC 4002-2628-1 is a low-amplitude (about 0.15 mag for $V$ band), short-period (0.3670495 d), contact eclipsing binary with a total secondary eclipse. Intrinsic light curve variations and the reversal of the O'Connell effect are detected in the light curves, which may be due to spot activity. Based on the photometric solutions derived from the multi-band time series light curves, TYC 4002-2628-1 is an extremely low mass ratio contact binary with a mass ratio of $q\sim$ 0.0482 and a fill-out factor of $f\sim5\%$. By analyzing the $O-C$ variations, we find that its orbital period remains unchanged when BJD < 2458321 . Then the orbital period changed suddenly around BJD 2458743 and has an increasing rate of $dP/dt=1.62\times{10^{-5}}day\cdot yr^{-1}=140$ $second\cdot century^{-1}$ . If confirmed, TYC 4002-2628-1 would be the contact binary with the highest orbital period increasing rate so far. By investigating the ratio of orbital angular momentum to the spin angular momentum ( $J_{orb}$/$J_{spin}$ $<3$) , the instability mass ratio ($q_{inst}/q=1.84$) and the instability separation ($A_{inst}/A=1.35$), TYC 4002-2628-1 can be regarded as a merger candidate.Comment: 9 page

Synthesis of renewable monomer 2, 5-bishydroxymethylfuran from highly concentrated 5-hydroxymethylfurfural in deep eutectic solvents

Abstract(#br)2, 5-Bishydroxymethylfuran (BHMF) has been currently emerged as a promising biomass-derived monomer. It is highly desirable to proceed a chemical process at a high substrate concentration, by which a facile and cost-effective separation of products can be expected. Herein, we report for the first time on the hydrogenation of highly concentrated 5-hydroxymethylfurfural (HMF) in deep eutectic solvents (DESs), giving a near quantitative selectivity towards BHMF in ChCl-glycerol DES at 25°C in 3h using NaBH 4 as the H-donor. DES is hailed as a new class of green solvent, in which HMF/BHMF could be stabilized by the strong hydrogen-bond interaction, and allowed the selective hydrogenation of HMF at high concentration up to 40wt%. Notably, the resulting BHMF could be facilely separated by extraction with ethyl acetate, and then high purity of BHMF with a desirable isolated yield around 80% was obtained after removing of ethyl acetate. Additionally, the reaction efficiency of HMF hydrogenation in DESs was verified to be strongly associated with the viscosity of DESs and the p K a value of hydrogen-bonding donor

Cascade conversion of furfural to fuel bioadditive ethyl levulinate over bifunctional zirconium-based catalysts

Abstract(#br)Biomass-derived ethyl levulinate (EL) is currently deemed as a promising fuel bioadditive to improve (bio)diesel combustion performance without the sacrifice of its octane number. In this contribution, a range of Zr–Al bimetallic catalysts were prepared for the cascade conversion of furfural to EL by the integration of transfer hydrogenation and ethanolysis in ethanol. The ratio of Lewis to Brønsted acid sites (L/B) could be tuned by the ratio of Al 2 O 3 to ZrO 2 over SBA-15 support. Among these catalysts, Zr–Al/SBA-15(30:10) with appropriate L/B ratio of 2.25 exhibited an outstanding catalytic performance to give a furfural (FF) conversion up to 92.8% with a EL selectivity as high as 71.4% at 453 K in 3 h

A flexible Cu-based catalyst system for the transformation of fructose to furanyl ethers as potential bio-fuels

Abstract(#br)Biomass-derived furanyl ethers, such as 5-alkoxymethylfurfurals (AMFs) and 2,5-bis(alkoxymethyl)furans (BAMFs), can be employed as promising biofuels or additives. The development of multifunctional catalysts for the efficient production of furanyl ethers from sugars through 5-hydroxymethylfurfural (HMF) as an intermediate is highly desirable but challenging, because multiple reactions including dehydration, etherification and hydrogenation get involved and the side reaction of sugars and HMF to form humins is inevitable. In this contribution, we found that the introduction of CuO resulted in the generation of Lewis acid sites at the cost of Bronsted acid sites over CuO-USY catalysts through the formation of Al-O-Cu(II) species. The dispersity of CuO particles and the amount of Lewis acid sites could be manipulated by adjusting the loading of CuO. If 5 wt% CuO was supported on USY zeolite to give a CuO(5)-USY catalyst, CuO particles with a high dispersity (36.4%) afforded abundant Lewis acid sites (457.1 μ mol/g). Lewis acid over CuO(5)-USY greatly promoted the acid-catalyzed dehydration of fructose to HMF and HMF etherification to AMFs, resulting in a HMF yield up to 86.2% from fructose and AMFs yields greater than 90% from HMF. Interestingly, a combination of CuO(5)-USY and a small amount of metallic Cu powder was able to offer desirable BAMFs yields by the reductive etherification of HMF under hydrogen atmosphere. As a result, 5-methoxymethylfurfural (MMF) of 79.6% and 2,5-bis(methoxymethyl)furan (BMMF) yield of 74.5% were achieved from fructose through HMF as an intermediate in the presence of CuO(5)-USY alone or with metallic Cu as a co-catalyst. Therefore, the above Cu-based catalyst system holds the promise to flexibly produce a family of AMFs or BAMFs from fructose via a facile two-step approach

A simulation study on the measurement of D0-D0bar mixing parameter y at BES-III

We established a method on measuring the \dzdzb mixing parameter $y$ for BESIII experiment at the BEPCII $e^+e^-$ collider. In this method, the doubly tagged $\psi(3770) \to D^0 \overline{D^0}$ events, with one $D$ decays to CP-eigenstates and the other $D$ decays semileptonically, are used to reconstruct the signals. Since this analysis requires good $e/\pi$ separation, a likelihood approach, which combines the $dE/dx$, time of flight and the electromagnetic shower detectors information, is used for particle identification. We estimate the sensitivity of the measurement of $y$ to be 0.007 based on a $20fb^{-1}$ fully simulated MC sample.Comment: 6 pages, 7 figure