An Improved Wavelet Packet-Chaos Model for Life Prediction of Space Relays Based on Volterra Series

<div><p>In this paper, an improved algorithm of wavelet packet-chaos model for life prediction of space relays based on volterra series is proposed. In the proposed method, the high and low frequency time sequence components of performance parameters are obtained by employing the improved wavelet packet transform to decompose the performance parameters of the relay into multiple scales. Then the optimization algorithm of parameters in volterra series is improved, and is used to construct a chaotic forecasting model for the high and low frequency time sequence components gained by the wavelet packet transform. At last, the chaotic forecasting results of the high and low frequency components are combined by taking the wavelet packet reconstruction approach, so as to predict the lifetime of the studied space relay. The algorithm can predict the life curve of the relay accurately and reflect the characteristics of the relay performance with sufficient accuracy. The proposed method is validated via a case study of a space relay.</p></div

Linum perrenne L.

原著和名: シュッコンアマナ科名: アマ科 = Linaceae採集地: 千葉県 千葉市 千葉大学 (下総 千葉市 千葉大学)採集日: 1955/9/1採集者: 萩庭丈壽整理番号: JH045219国立科学博物館整理番号: TNS-VS-99521

The high and low frequency components of wavelet packet decomposition.

<p>The high and low frequency components of wavelet packet decomposition.</p

Partial discharge chart of prediction results.

<p>Partial discharge chart of prediction results.</p

Optimal wavelet packet decomposition tree.

<p>Optimal wavelet packet decomposition tree.</p

The Lyapunov index values of eight high-low frequency component.

<p>The Lyapunov index values of eight high-low frequency component.</p

The schematic diagram of the three-level wavelet packet decomposition tree.

<p>The schematic diagram of the three-level wavelet packet decomposition tree.</p

Optimization and purification of glucansucrase produced by <i>Leuconostoc mesenteroides</i> DRP2-19 isolated from Chinese Sauerkraut

<p>Strain DRP2-19 was detected to produce high yield of glucansucrase in MRS broth, which was identified to be <i>Leuconostoc mesenteroides</i>. In order for industrial glucansucrase production of <i>L. mesenteroides</i> DRP2-19, a one-factor test was conducted, then response surface method was applied to optimize its yield and discover the best production condition. Based on Plackett–Burman (PB) experiment, sucrose, Ca²⁺, and initial pH were found to be the most significant factors for glucansucrase production. Afterwards, effects of the three main factors on glucansucrase activity were further investigated by central composite design and the optimum composition was sucrose 35.87 g/L, Ca²⁺ 0.21 mmol/L, and initial pH 5.56. Optimum results showed that glucansucrase activity was increased to 3.94 ± 0.43 U/mL in 24 hr fermentation, 2.66-fold higher than before. In addition, the crude enzyme was purified using ammonium sulfate precipitation, ion-exchange chromatography, and gel filtration. The molecular weight of glucansucrase was determined as approximately 170 kDa by Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The enzyme was purified 15.77-fold and showed a final specific activity of 338.56 U/mg protein.</p

PRISMA-P checklist.

(DOC)</p