352 research outputs found

    Analysis and Introduction of Effective Permeability with Additional Air-Gaps on Wireless Power Transfer Coils for Electric Vehicle based on SAE J2954 Recommended Practice

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    The wireless power transfer (WPT) method for electric vehicles (EVs) is becoming more popular, and to ensure the interoperability of WPT systems, the Society of Automotive Engineers (SAE) established the J2954 recommended practice (RP). It includes powering frequency, electrical parameters, specifications, testing procedures, and other contents for EV WPT. Specifically, it describes the ranges of self-inductances of the transmitting coil, the receiving coil, and coupling coefficient (k), as well as the impedance matching values of the WPT system. Following the electrical parameters listed in SAE J2954 RP is crucial to ensure the EV wireless charging system is interoperable. This paper introduces a method for adjusting the effective permeability of the ferrite blocks in the standard model, to tune the self-inductance of the coils as well as the coupling coefficient. To guarantee the given values of the self-inductance of the coil and coupling coefficient matched those in the standard, we slightly modified the air-gap between the ferrite tiles in a specific region. Based on this method, it was possible to successfully tune the self-inductance of the transmitting coil and receiving coil as well as the coupling coefficient. The proposed method was verified by simulation and experimental measurements

    Preparation and characterization of \u3ba-carrageenase immobilized onto magnetic iron oxide nanoparticles

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    Background: Carboxyl-functionalized magnetic nanoparticles were synthesized via chemical co-precipitation method and modified with oleic acid which was oxidized by potassium permanganate, and \u3ba-carrageenase from Pseudoalteromonas sp. ASY5 was subsequently immobilized onto them. The immobilization conditions were further optimized, and the characterizations of the immobilized \u3ba-carrageenase were investigated. Results: The \u3ba-carrageenase was immobilized onto magnetic iron oxide nanoparticles, and the bonding was verified by Fourier transform infrared spectroscopy. The optimal conditions for \u3ba-carrageenase immobilization were 2.5% (w/v) glutaraldehyde, 13.9 U \u3ba-carrageenase for 20 mg of magnetic nanoparticles, a 2-h cross-linking time, and a 2-h immobilization time at 25\ub0C. Under these conditions, the activity of the immobilized enzyme and the enzyme recovery rate were 326.0 U \ub7 g-1 carriers and 46.9%, respectively. The properties of the immobilized \u3ba-carrageenase were compared with those of the free enzyme. The optimum temperatures of the free and immobilized \u3ba-carrageenase were 60 and 55\ub0C, respectively, and the optimum pH of \u3ba-carrageenase did not change before and after immobilization (pH 7.5). After immobilization, \u3ba-carrageenase exhibited lower thermal stability and improved pH stability, as well as better storage stability. The immobilized \u3ba-carrageenase maintained 43.5% of the original activity after being used 4 times. The kinetic constant value (Km) of \u3ba-carrageenase indicates that the immobilized enzyme had a lower binding affinity for the substrate. Conclusions: Under optimal conditions, the activity of the immobilized enzyme and enzyme recovery rate were 326.0 U \ub7 g-1\ub7\u3ba-carrageenase-CMNPs and 46.9%, respectively. The thermal, pH, and storage stabilities of \u3ba-carrageenase-CMNPs were relatively higher than those of free \u3ba-carrageenase

    Efficient immobilization of agarase using carboxyl-functionalized magnetic nanoparticles as support

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    Background: A simple and efficient strategy for agarase immobilization was developed with carboxyl-functionalized magnetic nanoparticles (CMNPs) as support. The CMNPs and immobilized agarase (agarase-CMNPs) were characterized by transmission electron microscopy, dynamic light scattering, vibrating sample magnetometry, scanning electron microscopy, X-ray diffraction, thermogravimetric analysis, and zeta-potential analysis. The hydrolyzed products were separated and detected by ESI-TOF-MS. Results: The agarase-CMNPs exhibited a regular spherical shape with a mean diameter of 12 nm, whereas their average size in the aqueous solution was 43.7 nm as measured by dynamic light scattering. These results indicated that agarase-CMNPs had water swelling properties. Saturation magnetizations were 44 and 29 emu/g for the carriers and agarase-CMNPs, respectively. Thus, the particles had superparamagnetic characteristics, and agarase was successfully immobilized onto the supports. Agaro-oligosaccharides were prepared with agar as substrate using agarase-CMNPs as biocatalyst. The catalytic activity of agarase-CMNPs was unchanged after six reuses. The ESI-TOF mass spectrogram showed that the major products hydrolyzed by agarase-CMNPs after six recycle uses were neoagarotetraose, neoagarohexaose, and neoagarooctaose. Meanwhile, the end-products after 90 min of enzymatic treatment by agarase-CMNPs were neoagarobiose and neoagarotetraose. Conclusions: The enhanced agarase properties upon immobilization suggested that CMNPs can be effective carriers for agarase immobilization. Agarase-CMNPs can be remarkably used in developing systems for repeated batch production of agar-derived oligosaccharides

    Multidifferential study of identified charged hadron distributions in ZZ-tagged jets in proton-proton collisions at s=\sqrt{s}=13 TeV

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    Jet fragmentation functions are measured for the first time in proton-proton collisions for charged pions, kaons, and protons within jets recoiling against a ZZ boson. The charged-hadron distributions are studied longitudinally and transversely to the jet direction for jets with transverse momentum 20 <pT<100< p_{\textrm{T}} < 100 GeV and in the pseudorapidity range 2.5<η<42.5 < \eta < 4. The data sample was collected with the LHCb experiment at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 1.64 fb−1^{-1}. Triple differential distributions as a function of the hadron longitudinal momentum fraction, hadron transverse momentum, and jet transverse momentum are also measured for the first time. This helps constrain transverse-momentum-dependent fragmentation functions. Differences in the shapes and magnitudes of the measured distributions for the different hadron species provide insights into the hadronization process for jets predominantly initiated by light quarks.Comment: All figures and tables, along with machine-readable versions and any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2022-013.html (LHCb public pages

    Study of the B−→Λc+Λˉc−K−B^{-} \to \Lambda_{c}^{+} \bar{\Lambda}_{c}^{-} K^{-} decay

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    The decay B−→Λc+Λˉc−K−B^{-} \to \Lambda_{c}^{+} \bar{\Lambda}_{c}^{-} K^{-} is studied in proton-proton collisions at a center-of-mass energy of s=13\sqrt{s}=13 TeV using data corresponding to an integrated luminosity of 5 fb−1\mathrm{fb}^{-1} collected by the LHCb experiment. In the Λc+K−\Lambda_{c}^+ K^{-} system, the Ξc(2930)0\Xi_{c}(2930)^{0} state observed at the BaBar and Belle experiments is resolved into two narrower states, Ξc(2923)0\Xi_{c}(2923)^{0} and Ξc(2939)0\Xi_{c}(2939)^{0}, whose masses and widths are measured to be m(Ξc(2923)0)=2924.5±0.4±1.1 MeV,m(Ξc(2939)0)=2938.5±0.9±2.3 MeV,Γ(Ξc(2923)0)=0004.8±0.9±1.5 MeV,Γ(Ξc(2939)0)=0011.0±1.9±7.5 MeV, m(\Xi_{c}(2923)^{0}) = 2924.5 \pm 0.4 \pm 1.1 \,\mathrm{MeV}, \\ m(\Xi_{c}(2939)^{0}) = 2938.5 \pm 0.9 \pm 2.3 \,\mathrm{MeV}, \\ \Gamma(\Xi_{c}(2923)^{0}) = \phantom{000}4.8 \pm 0.9 \pm 1.5 \,\mathrm{MeV},\\ \Gamma(\Xi_{c}(2939)^{0}) = \phantom{00}11.0 \pm 1.9 \pm 7.5 \,\mathrm{MeV}, where the first uncertainties are statistical and the second systematic. The results are consistent with a previous LHCb measurement using a prompt Λc+K−\Lambda_{c}^{+} K^{-} sample. Evidence of a new Ξc(2880)0\Xi_{c}(2880)^{0} state is found with a local significance of 3.8 σ3.8\,\sigma, whose mass and width are measured to be 2881.8±3.1±8.5 MeV2881.8 \pm 3.1 \pm 8.5\,\mathrm{MeV} and 12.4±5.3±5.8 MeV12.4 \pm 5.3 \pm 5.8 \,\mathrm{MeV}, respectively. In addition, evidence of a new decay mode Ξc(2790)0→Λc+K−\Xi_{c}(2790)^{0} \to \Lambda_{c}^{+} K^{-} is found with a significance of 3.7 σ3.7\,\sigma. The relative branching fraction of B−→Λc+Λˉc−K−B^{-} \to \Lambda_{c}^{+} \bar{\Lambda}_{c}^{-} K^{-} with respect to the B−→D+D−K−B^{-} \to D^{+} D^{-} K^{-} decay is measured to be 2.36±0.11±0.22±0.252.36 \pm 0.11 \pm 0.22 \pm 0.25, where the first uncertainty is statistical, the second systematic and the third originates from the branching fractions of charm hadron decays.Comment: All figures and tables, along with any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2022-028.html (LHCb public pages

    Measurement of the ratios of branching fractions R(D∗)\mathcal{R}(D^{*}) and R(D0)\mathcal{R}(D^{0})

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    The ratios of branching fractions R(D∗)≡B(Bˉ→D∗τ−Μˉτ)/B(Bˉ→D∗Ό−ΜˉΌ)\mathcal{R}(D^{*})\equiv\mathcal{B}(\bar{B}\to D^{*}\tau^{-}\bar{\nu}_{\tau})/\mathcal{B}(\bar{B}\to D^{*}\mu^{-}\bar{\nu}_{\mu}) and R(D0)≡B(B−→D0τ−Μˉτ)/B(B−→D0Ό−ΜˉΌ)\mathcal{R}(D^{0})\equiv\mathcal{B}(B^{-}\to D^{0}\tau^{-}\bar{\nu}_{\tau})/\mathcal{B}(B^{-}\to D^{0}\mu^{-}\bar{\nu}_{\mu}) are measured, assuming isospin symmetry, using a sample of proton-proton collision data corresponding to 3.0 fb−1{ }^{-1} of integrated luminosity recorded by the LHCb experiment during 2011 and 2012. The tau lepton is identified in the decay mode τ−→Ό−ΜτΜˉΌ\tau^{-}\to\mu^{-}\nu_{\tau}\bar{\nu}_{\mu}. The measured values are R(D∗)=0.281±0.018±0.024\mathcal{R}(D^{*})=0.281\pm0.018\pm0.024 and R(D0)=0.441±0.060±0.066\mathcal{R}(D^{0})=0.441\pm0.060\pm0.066, where the first uncertainty is statistical and the second is systematic. The correlation between these measurements is ρ=−0.43\rho=-0.43. Results are consistent with the current average of these quantities and are at a combined 1.9 standard deviations from the predictions based on lepton flavor universality in the Standard Model.Comment: All figures and tables, along with any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2022-039.html (LHCb public pages

    A Global Value Chain Analysis of Chinas Virtual Water Footprint Through Agricultural Trade

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    The use of the global value chain (GVC) method has been gaining traction in recent research on resource use for production and trade. China has become one of the largest centers for forward- and backward-linkages for trade in inputs for agricultural and food products. Traditional methods of virtual water (VW) trade show the overestimation of China’s use of foreign VW. Here, we use global value chain analysis based on the GTAP database to get the embodied trade of VW for China in the major agricultural sectors and agro-based industries. We find that China is a net importer of blue VW through its trade in primary and net exporter of blue VW through the processed agricultural commodities. It is a net importer of green VW through primary and processed agricultural commodities. The GVC method reveals that China is partially responsible for the imports of blue water, while the rest of the imports are caused by other countries through their imports of blue VW from China. We conclude that the sustainability of global water resources can be achieved through better estimates on VW trade and sharing the responsibility by the end-users
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