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In the linear induction motor control system, the optical grating speed transducer is susceptible to strong magnetic field interference. What's more, it may reduce motor integration and raise device costs. Therefore a speed identification method to replace grating speed transducer is studied in this article. This speed identification method for linear induction motor mainly adopts Model Reference Adaptive Method (Abbreviated as MRAS) and Popov Hyperstability Theory. The research content of this paper can be divided into four parts. First, the mathematical model of the motor based on the model reference adaptive system structure is deduced. Second, the adaptive law of the estimated speed is solved by Popov hyper-stability theory, which ensures the stability of the system. Third, the simulation model of the linear induction motor speed identification control system based on model reference adaptation is built in the MATLAB environment. Finally, the simulation test and analysis are carried out. The simulation results show that the speed identification control system can track the actual speed of the linear induction motor well in the no-load operation and the load operation, and the stability of the system is guaranteed in the full speed range.

The microstructure and oxidation behaviour of the pure AlON ceramics and 8 wt.% SiC-AlON composite were investigated at 700-1500°C. With increasing oxidation temperature, the surface morphology of two ceramics showed a change from acicular to flaky-like and then to granular features. With the addition of nanosized SiC particles, the oxidation resistance of the ceramics was remarkably enhanced above 1100°C. This is attributed to the formation of a dense oxide layer composed of Al2O3, SiO2 and mullite, which could cover the whole matrix and suppress further penetration of oxygen. Due to the dense oxide layer, the oxidation kinetics of the 8 wt.% SiC-AlON composites conformed to a parabolic law, while that of the pure AlON conformed to a linear law. After oxidation at 1500 °C for 40 h, the weight gain of the 8 wt.% SiC-AlON composites was 3.07mg/cm2, which was only 22.5% of that of the pure AlON.

The synthesis and crystal structure of peptide 6,6′-dimethyl biphenyl hybrid are described. The title compound was synthesized by reaction between 6,6′-dimethyl-[1,1′-biphenyl]-2,2′-dicarbonyl dichloride in CH2Cl2, amine HN–proline–phenylalanine–alanine–COOMe and Et3N at 273 K under N2 atmosphere and characterized by single-crystal X-ray diffraction. The asymmetric unit contains one peptide molecule and a quarter of a water molecule. A disorder of a methyl and methoxycarbonyl group of one alanine residue is observed with occupancy ratio 0.502 (6):0.498 (6). The structure is consolidated by intra- and intermolecular hydrogen bonds.

A peptide biphenyl hybrid compound {systematic name: dimethyl 2,2′-[((2S,2′S)-2,2′-{[(2S,2′S)-1,1′-([1,1′-biphenyl]-2,2′-dicarbonyl)bis(pyrrolidine-1,2-diyl-2-carbonyl)]bis(azanediyl)}bis(3-phenylpropanoyl))bis(azanediyl)](2S,2′S)-dipropionate hemihydrate}, C50H56N6O10·0.5H2O, was prepared by coupling of [1,1′-biphenyl]-2,2′-dicarbonyl dichloride, triethylamine and the tripeptide Pro–Phe–Ala in CH2Cl2 at 273 K under an N2 atmosphere. In the crystal, the asymmetric unit contains the peptide biphenyl hybrid accompanied by one-half of a water molecule. A C atom of one of the proline rings is disordered between two positions in a 0.746 (11):0.254 (11) ratio. An important structural aspect of peptide compounds is their capacity to self-associate mediated by intermolecular and intramolecular hydrogen bonding. This characteristic can be useful in understanding the interactions between peptides and biomacromolecular targets, as well as to explain peptide properties.

Seeking a strategy for triggering the cryptic natural product biosynthesis to yield novel compounds in the plant-associated fungus Xylaria sp., the effect of culture conditions on metabolite production was investigated. A shift in the production of five known cytochalasin-type analogues 1–5 to six new α-pyrone derivatives, xylapyrones A–F (compounds 6–11), from a solid to a liquid medium was observed. These compounds were identified by analysis of 1D and 2D NMR and HRMS data. Compounds 1–3 showed moderate cytotoxicity against HepG2 and Caski cancer cell lines with IC50 values ranging from 25 to 63 μM and compounds 4–11 were found to be inactive, with IC50 values >100 μM.

Five new 2(5H)-furanone-type derivatives, pestalafuranones F–J (compounds 3–7), together with two known compounds, pestalafuranones A (1) and B (2), were isolated from the ethyl acetate extract from the fermentation broth of the endophytic fungus Nigrospora sp. BM-2 in a hypersaline medium. The structures of these metabolites were elucidated by EIMS, HREIMS and NMR spectroscopic data. Compounds 1–7 exhibited no cytotoxic activities against the MDA-MB-231 and Caski cancer cell lines.

Waste sorting in urban villages is a less developed while important issue in waste management and it is of great importance to environmental sustainability. China is now facing challenges of combating waste sorting while little attention has been paid to these challenges in urban villages. This article aims to add to this knowledge by examining how waste sorting has been implemented in urban villages via a case study of Shenzhen, China. A co-production theory perspective is adopted to explore how actors are engaged in the process of waste sorting and what are the results. The findings suggest coproduction approach is neither a top-down nor bottom-up approach. It is a much more complex process that involves intensive interactions between the government and residents. It concludes that the co-production approach to waste sorting exemplified by urban villages' sustainable development has great significance for general environmental management and policy making in the long term. [ABSTRACT FROM AUTHOR]