Test method about transient characteristics of Relay protection calibration apparatus

AbstractRelay protection calibration apparatus is used to detect whether the Relay protection instrument satisfy their performance index. This article introduces the high-speed data acquisition system based on ADS930, proposes the interpolation algorithm aims to improve test accuracy in signal processing. It describes the method of filter smoothing to remove interference. Results illustrate the technique is correct and practical

Delineating urban functional zones using mobile phone data: A case study of cross-boundary integration in Shenzhen-Dongguan-Huizhou area

As cities continuously expand and with the emergence of mega-city regions, the urban functional zones (UFZs) have spread beyond their original administrative boundaries. An accurate and updated delineation of the UFZs is crucial for assessing the functional integration between cities within a mega-city region. Mobility data provides a chance to depict the UFZs from actual human activities at a finer spatial scale. Existing studies mostly adopted network-based approaches relying on the topological relationship but ignoring spatial factors, causing the lack of sensitivity in detecting the cross-cities integration of the functional region. This research proposed a novel regionalisation algorithm that redraws non-overlap boundaries of urban functional zones based on the commuting origin-destination matrix, representing the spatial interactions within cities and cross-cities. In particular, functional zones are drawn by searching for the best partition with the best goodness of fitting in the hierarchical spatial interaction model. The algorithm was applied to a case study of a mega-city region, Shenzhen-Dongguan-Huizhou (SDH) area in China using mobile phone signalling data. By adopting two different settings, this model evaluated the current status and predict the future trend of urban integration respectively. The results show the current boundary of UFZs in the SDH area almost coincides with administrative boundaries. Meanwhile, the results of long-term predictions might be utilised by policymakers to give more attention to the areas near the Dongguan-Huizhou boundary to promote industry cooperation and avoid mismatches between the functional and administrative regions

Literature Analysis of Energy Storage Research Based on Object Hierarchy

[Introduction] With the development of energy storage technology, technical schemes and application scenarios become more and more complex. For energy storage research, the conventional classification method based on technical route has certain limitations in some cases. [Method] A classification method of energy storage research based on object hierarchy was proposed: according to the hierarchy order of objects from micro to macro, energy storage researches were divided into material-level, device-level, system & power plant-level and power system-level. This method was applied to the quantitative analysis of 5 397 articles published in journals of energy storage research retrieved by CNKI. [Result] The results show that the number of power system-level research literatures in 2022 is obviously more than other types of literatures, and the number and cumulative citation times of power system-level research literatures in the top 200 literatures cited from 2001 to 2022 are absolutely superior. Before 2010, material-level and device-level research literatures account for a relatively high proportion. Since 2010, the proportion of system & power plant-level and power system-level research literatures has gradually increased, and the growth rate of power system-level research literatures is more obvious. The newly installed capacity of new energy storage from 2011 to 2022 is positively correlated with the number of literatures. Since the system & power plant-level research often directly focuses on actual projects, the number of such literatures is most closely related to the newly installed capacity. [Conclusion] A new way to summarize the research results of energy storage is provided, which could provide support for industrial policy formulation, industrial chain layout and other work

Antagonistic Actions of Juvenile Hormone and 20-Hydroxyecdysone Within the Ring Gland Determine Developmental Transitions in \u3cem\u3eDrosophila\u3c/em\u3e

In both vertebrates and insects, developmental transition from the juvenile stage to adulthood is regulated by steroid hormones. In insects, the steroid hormone, 20-hydroxyecdysone (20E), elicits metamorphosis, thus promoting this transition, while the sesquiterpenoid juvenile hormone (JH) antagonizes 20E signaling to prevent precocious metamorphosis during the larval stages. However, not much is known about the mechanisms involved in cross-talk between these two hormones. In this study, we discovered that in the ring gland (RG) of Drosophila larvae, JH and 20E control each other’s biosynthesis. JH induces expression of a Krüppel-like transcription factor gene Kr-h1 in the prothoracic gland (PG), a portion of the RG that produces the 20E precursor ecdysone. By reducing both steroidogenesis autoregulation and PG size, high levels of Kr-h1 in the PG inhibit ecdysteriod biosynthesis, thus maintaining juvenile status. JH biosynthesis is prevented by 20E in the corpus allatum, the other portion of the RG that produces JH, to ensure the occurrence of metamorphosis. Hence, antagonistic actions of JH and 20E within the RG determine developmental transitions in Drosophila. Our study proposes a mechanism of cross-talk between the two major hormones in the regulation of insect metamorphosis

Experiments on bright field and dark field high energy electron imaging with thick target material

Using a high energy electron beam for the imaging of high density matter with both high spatial-temporal and areal density resolution under extreme states of temperature and pressure is one of the critical challenges in high energy density physics . When a charged particle beam passes through an opaque target, the beam will be scattered with a distribution that depends on the thickness of the material. By collecting the scattered beam either near or off axis, so-called bright field or dark field images can be obtained. Here we report on an electron radiography experiment using 45 MeV electrons from an S-band photo-injector, where scattered electrons, after interacting with a sample, are collected and imaged by a quadrupole imaging system. We achieved a few micrometers (about 4 micrometers) spatial resolution and about 10 micrometers thickness resolution for a silicon target of 300-600 micron thickness. With addition of dark field images that are captured by selecting electrons with large scattering angle, we show that more useful information in determining external details such as outlines, boundaries and defects can be obtained.Comment: 7pages, 7 figure

Enhancing the biosynthesis of riboflavin in the recombinant Escherichia coli BL21 strain by metabolic engineering

In this study, to construct the riboflavin-producing strain R1, five key genes, ribA, ribB, ribC, ribD, and ribE, were cloned and ligated to generate the plasmid pET-AE, which was overexpressed in Escherichia coli BL21. The R1 strain accumulated 182.65 ± 9.04 mg/l riboflavin. Subsequently, the R2 strain was constructed by the overexpression of zwf harboring the constructed plasmid pAC-Z in the R1 strain. Thus, the level of riboflavin in the R2 strain increased to 319.01 ± 20.65 mg/l (74.66% increase). To further enhance ribB transcript levels and riboflavin production, the FMN riboswitch was deleted from E. coli BL21 with CRISPR/Cas9 to generate the R3 strain. The R4 strain was constructed by cotransforming pET-AE and pAC-Z into the R3 strain. Compared to those of E. coli BL21, the ribB transcript levels of R2 and R4 improved 2.78 and 3.05-fold, respectively. The R4 strain accumulated 437.58 ± 14.36 mg/l riboflavin, increasing by 37.17% compared to the R2 strain. These results suggest that the deletion of the FMN riboswitch can improve the transcript level of ribB and facilitate riboflavin production. A riboflavin titer of 611.22 ± 11.25 mg/l was achieved under the optimal fermentation conditions. Ultimately, 1574.60 ± 109.32 mg/l riboflavin was produced through fed-batch fermentation with 40 g/l glucose. This study contributes to the industrial production of riboflavin by the recombinant E. coli BL21