Supercapacitor has been considered one of the most promising energy storage devices and has been widely used in new energy generation, electric vehicles, pulse power supply and other fields in these years. Because supercapacitor can charge and discharge at large current, it has been employed to output and absorb peak power in energy storage systems. In those applications, the state-of-charge(SOC) of supercapacitor is usually calculated in Amper-Hour integral (AHI) measurement. Though the nonlinearity of supercapacitor working process isn't as intense as that of lithium battery, the SOC estimation error of AHI for supercapacitor can't be ignored. In this paper, a SOC estimation method of supercapacitor with Kalman filtering algorithm is proposed. Firstly, the equivalent circuit model of supercapacitor is established, and the function relationship between its open circuit voltage and SOC is obtained by theoretical analysis and experimental test. Then parameters of the equivalent circuit model are updated with Forgetting Factor Least Square method. Finally Kalman filter operator is designed by using the state equation of charge and discharge of supercapacitor. The experiment result shows the estimation error is ranging from −0.51 % to 0.07% and RMSE is 0.0023, which indicates the accuracy of the SOC estimation algorithm.
We discuss the recent breakthrough in the field of photonic integrated circuits for generating high-quality photonic structures on lithium niobate (LN) on insulator (LNOI). This is enabled by the development of chemo-mechanical polish lithography (CMPL). We begin with a brief introduction of the background, followed by the description of the CMPL technique that holds the promise for realizing LNOI waveguides of ultralow propagation loss approaching the absorption limit of LN. We demonstrate fabrication of low loss optical waveguides with the CMPL and construction of beamsplitters with the fabricated LNOI waveguides. At last, some conclusions and future perspectives will be given. A video abstract of this article can be found at: https://youtu.be/sgnecU_QzcY
Abstract High-Q semi-2D-photonic crystal cavities with a tapered edge and side-coupled bus waveguide are demonstrated. With a quadratic design, the unloaded cavity presents a theoretical ultrahigh quality factor up to 6.7 × 10 7 for the condition that there are mere 34 holes in the propagated direction, which is pretty close to the 2D and 1D counterpart. Combined with a side-coupled bus waveguide, an all-pass-type cavity with a loaded quality factor (Q) of over 2.4 × 10 4 and an extinction ratio over 10 dB are experimentally demonstrated. An experimental loaded Q up to 1.1 × 10 5 are also achieved by tuning the coupling between the cavity and the bus waveguide, which is much larger than any reported surface-mode cavity. This cavity is quite suitable for sensors, filters and especially optomechanical devices thanks to the mechanical stability of the cavity and flexibility of the bus waveguide.
An on-chip 2*2 3dB coupler designed for multimode waveguide is demonstrated. The two modes from the input multimode waveguide can be simultaneously split in half to the two output multimode waveguides with a 21.8μm long coupling region.
We report on a nanostructured silicon resonator achieving optomechanical coupling between C-band photons and X-band phonons. We experimentally show the generation of 10GHz phonons, with decay rate of 3.49 MHz. This result opens new prospects for high-frequency silicon optomechanics with applications in communications, sensing and quantum-state control.
Periodically patterning silicon with a subwavelength period enables flexible control of the propagation of light and sound in silicon photonic circuits. In this invited presentation, we will show our most recent demonstration of supercontinuum generation in the near-IR and mid-IR using suspended silicon waveguides. We will also discuss our recent results on subwavelength engineering of photons and phonons in suspended and non-suspended silicon optomechanical cavities
Ca-mediated processes are known to be involved in transducing many developmental, hormonal, and environmental cues in plant cells. In this study, the role of Ca in the perception of anoxic stress signals by maize (Zea mays L. cv B73) roots was assessed by studying the effect of various Ca antagonists on the induction of alcohol dehydrogenase (ADH) and sucrose synthase mRNA as well as ADH activity under anoxia. The effect of these compounds on the poststress recovery of the seedlings was also monitored. Ruthenium red (RR), an inhibitor of organellar Ca fluxes, repressed the anoxic activation of the alcohol dehydrogenase1 and shrunken1 genes as measured by their transcript levels as well as ADH activity. Furthermore, RR-treated seedlings could not recover even after only 2 h of flooding, in contrast to untreated B73 seedlings that survived 72 h of submergence. Ca, when supplied along with RR, allowed normal anoxic gene expression and also prevented the RR-imposed death of the seedlings from short-term anoxia. Ca (45Ca) fluxes were measured in maize roots to elucidate the mode of action of RR. RR abolished anoxia-stimulated 45Ca influx into maize roots but did not affect aerobic Ca2+ uptake, unlike a few other antagonists that blocked both the aerobic and anoxic fluxes. However, Ca uptake across the plasma membrane was not necessary for the adaptive response to anoxia, since chelation of extracellular Ca by ethyleneglycol-bis([beta]-aminoethyl ether)-N,N[prime] -tetraacetic acid or 1,2-bis(2-aminophenoxy)ethane N,N,N[prime],N[prime] -tetraacetic acid did not affect the induction of ADH activity or poststress survival of flooded seedlings. The data suggest that RR may act on one of the intracellular stores of Ca and the Ca mobilized from this source is a physiological transducer of anoxic stress signals in maize roots.
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