Research of Active Power Filter Modeling with Grid Impedance in Feedback Linearization and Quasi-Sliding Mode Control

Active power filter (APF) is the most popular device in regulating power quality issues. Currently, most literatures ignored the impact of grid impedance and assumed the load voltage is ideal, which had not described the system accurately. In addition, the controllers applied PI control; thus it is hard to improve the compensation quality. This paper establishes a precise model which consists of APF, load, and grid impedance. The Bode diagram of traditional simplified model is obviously different with complete model, which means the descriptions of the system based on the traditional simplified model are inaccurate and incomplete. And then design exact feedback linearization and quasi-sliding mode control (FBL-QSMC) is based on precise model in inner current loop. The system performances in different parameters are analyzed and dynamic performance of proposed algorithm is compared with traditional PI control algorithm. At last, simulations are taken in three cases to verify the performance of proposed control algorithm. The results proved that the proposed feedback linearization and quasi-sliding mode control algorithm has fast response and robustness; the compensation performance is superior to PI control obviously, which also means the complete modeling and proposed control algorithm are correct

Petrography and mineralogy of new lunar meteorite MIL090036

MIL090036 is a previously unknown meteorite (a feldspathic lunar breccia) that was discovered in Antarctica. The detailed petrography and mineralogy of this meteorite forms the subject of this paper. It has a typical clastic texture that consists of various types of rock debris (e.g. anorthosite, gabbroic anorthosite, gabbro, regolith breccia, troctolite, microporphyritic crystalline impact melt and compound clasts), mineral crystal fragments (e.g. pyroxenes, plagioclase, olivine and ilmenite) and feldspathic glass clasts. The fine-grained recrystallized minerals and mineral clasts are cemented together in a glassy groundmass. The anorthite content of plagioclase in the gabbro (An81-83) and anorthosite (An88-93) both have relatively low calcium content compared to those from other breccias (An90-98). The pyroxene composition (Fs12-35 Wo3-44 En22-79) in the rock debris, crystal mineral clasts and anorthositic glass clasts are relatively iron-deficient compared to those from gabbro debris with melt glass (Fs37-65 Wo10-29 En21-49) and groundmass (Fs18-69 Wo3-45 En14-50). In contrast, the pyroxene grains in the gabbroic anorthosite display a narrow compositional range (Fs24-27 Wo7-14 En59-69). Olivine grains in mineral fragments and the groundmass have a wider compositional range (Fo57-79) than those in the rock debris (Fo67-77). The Fe/Mn ratio in olivine is in the range of 47 to 83 (average 76) and 76 to 112 (average 73) in pyroxenes, and hence classify within the lunar field. The characteristics of texture, mineral assemblage and compositions suggest that MIL090036 possibly originated from a region beyond that of the Apollo and Luna samples. Further study of MIL090036 is therefore likely to lead to a better understanding of the geological processes on the Moon and the chemical composition of the lunar crust

Lunar meteorites: witnesses of the composition and evolution of the Moon

Lunar meteorites are fragments of the Moon that escaped the gravity of the Moon following high-energy impacts by asteroids, subsequently fell to Earth. An inventory of 165 lunar meteorites has been developed since the discovery and identification of the first lunar meteorite, ALHA 81005, in 1979. Although the Apollo samples are much heavier in mass than lunar meteorites, the meteorites are still an important sample supplement for scientific research on the composition and history of the Moon. Apart from a small amount of unbrecciated crystalline rocks, the majority of lunar meteorites are breccias that can be classified into three groups: highland feldspathic breccia, mare basaltic breccia, and mingled(including fledspathic and basaltic clasts) breccia. The petrography of lunar rocks suggests that there are a series of rock types of anorthosite, basalt, gabbro, troctolite, norite and KREEP in the Moon. Although KREEP is rare in lunar rocks, KREEP components have been found in the increasing number of lunar meteorites. KREEP provides important information on lunar magmatic evolution, e.g., the VHK KREEP clasts in SaU 169 may represent the pristine lunar magma (urKREEP). Six launching pairs of lunar meteorites have been proposed now, along with ten possible lunar launching sites. In addition, symplectite is often found in lunar basalts, which is a significant record of shock metamorphism on the lunar surface. Furthermore, isotopic ages and noble gases not only provide information on crystallization processes in lunar rocks and the formation of lunar crust, but also provide insight into shock events on the lunar surface

Meteorite classification for building the Chinese Antarctic Meteorite Depository—Introduction of the classification of 500 Grove Mountains meteorites

Meteorites provide an important window into the origins and evolution of the solar system. Since the first four meteorites were recovered in Grove Mountains, Antarctica, in 1998, a further total of 12665 meteorites have been collected over seven polar seasons in the Grove Mountains. All of these meteorites are owned and managed by the Chinese Antarctic Meteorite Depository (CAMD) at the Polar Research Institute of China (PRIC). In recent years, another 500 Antarctic meteorites have been classified and characterized based on mineralogy and petrology. In this work we examine four samples that have been identified as terrestrial, and a further 496 samples that have been confirmed as meteorites. These meteorites are further divided into different types:488 ordinary chondrites, one eucrite, one ureilite, one CM2 carbonaceous chondrite, one EH4 enstatite chondrite, one mesosiderite and three iron meteorites. The classification of meteorites not only provides an abundance of fundamental scientific data, but is also significant for introducing meteorites and related scientific knowledge to the public, particularly via the website of Chinese Resource-sharing Platform of Polar Samples for scientific research and education

Purification, characterization and degradation performance of a novel dextranase from Penicillium cyclopium CICC-4022

A novel dextranase was purified from CICC-4022 by ammonium sulfate fractional precipitation and gel filtration chromatography. The effects of temperature, pH and some metal ions and chemicals on dextranase activity were investigated. Subsequently, the dextranase was used to produce dextran with specific molecular mass. Weight-average molecular mass () and the ratio of weight-average molecular mass/number-average molecular mass, or polydispersity index (/), of dextran were measured by multiple-angle laser light scattering (MALS) combined with gel permeation chromatography (GPC). The dextranase was purified to 16.09-fold concentration; the recovery rate was 29.17%; and the specific activity reached 350.29 U/mg. of the dextranase was 66 kDa, which is similar to dextranase obtained from other species reported previously. The highest activity was observed at 55 °C and a pH of 5.0. This dextranase was identified as an endodextranase, which specifically degraded the α-1,6 glucosidic bonds of dextran. According to metal ion dependency tests, Li⁺, Na⁺ and Fe were observed to effectively improve the enzymatic activity. In particular, Li⁺ could improve the activity to 116.28%. Furthermore, the dextranase was efficient at degrading dextran and the degradation rate can be well controlled by the dextranase activity, substrate concentration and reaction time. Thus, our results demonstrate the high potential of this dextranase from CICC-4022 as an efficient enzyme to produce specific clinical dextrans

Influences of microplastics types and size on soil properties and cadmium adsorption in paddy soil after one rice season

Microplastics (MPs) were considered as emerging pollutants in soil. Cadmium (Cd) is the typical heavy metal contaminant in paddy soil in China. It was not unraveled that the effects of the existence of MPs on soil properties and Cd adsorption after rice growth in paddy soil, one of the most important soil types in China. In this study, several typical MPs in dosage of 0.5% (w/w) with different particle sizes, including polyethylene (PE, 200μm), polyacrylonitrile (PAN, 200μm), and polyethylene terephthalate (PET, 200 and 10μm), were selected and aged for a rice season (∼6 months) in paddy soil by column experiments. Some essential physicochemical properties of paddy soil collected from different treatments and the adsorption performance of typical metal contaminants (cadmium, Cd) in paddy soil with MPs coexisting were compared. The results indicated that the 6-month existence of 200μmMPs increased water content (15.94% to 26.08-30.30%), pH value (7.05 to 7.16–7.33), organic matter (OM) content (15.1 gkg −1 to 18.2–22.9 gkg −1), the percentage of soil sand and Cd adsorption capacity of paddy soil, whereas decreased soil cation exchange capacity (CEC), the percentage of soil clay and silt. The adsorption experiments of Cd in soil showed that the adsorption behavior was consistent with the pseudo-second order and Langmuir isotherm model, and the addition of MPs would increase the adsorption capacity of Cd in soil. Besides, the particle size of MPs was found to be one of the dominant factors, in which MPs with smaller particle size (10μm) favored the increase of water content, pH, OM content, CEC, and adsorption performance with Cd. The results of this study could provide a supplemental understanding of the effect of MPs input on the paddy soil ecosystem, including the soil properties and the bioavailability and transport of metal in paddy soil

Cancer-associated fibroblasts induce growth and radioresistance of breast cancer cells through paracrine IL-6

Abstract In breast cancer, the most numerous stromal cells are cancer-associated fibroblasts (CAFs), which are associated with disease progression and chemoresistance. However, few studies have explored the function of CAFs in breast cancer cell radiosensitivity. Here, CAF-derived conditioned media was observed to induce breast cancer cell growth and radioresistance. CAFs secrete interleukin 6 (IL-6) which activates signal transducer and activator of transcription 3 (STAT3) signaling pathway, thus promoting the growth and radioresistance of breast cancer cells. Treatment with an inhibitor of STAT3 or an IL-6 neutralizing antibody blocked the growth and radioresistance induced by CAFs. In in vivo mouse models, tocilizumab (an IL-6 receptor monoclonal antibody) abrogated CAF-induced growth and radioresistance. Moreover, in breast cancer, a poor response to radiotherapy was associated with IL-6 and p-STAT3 expression. These results indicated that IL-6 mediates cross-talk between breast cancer cells and CAFs in the tumor microenvironment. Our results identified the IL-6/STAT3 signaling pathway as an important therapeutic target in breast cancer radiotherapy

Chemical Probes Reveal Sirt2’s New Function as a Robust “Eraser” of Lysine Lipoylation

10.1021/jacs.9b06913J. Am. Chem. Soc.1414618428–1843