This paper proposes a dynamic synthetic inertia control method, considering the fatigue loads of the wind turbine. The control objectives include reducing the rate of change of frequency and frequency nadir of the power system and the fatigue load of the shaft and tower of the wind turbine. A frequency regulation model of the power system containing the primary operating dynamics of the wind turbine is established. The dynamic synthetic inertia control method is proposed according to the relationship between fatigue load, wind velocity, and frequency. Case studies are conducted with a wind turbine fatigue load under a synthetic inertia control with different weights for different wind velocities and system loads. Therefore, the dynamic weights are obtained. Comparing the rate of change of frequency and frequency nadir and equivalent damage load, the efficacy of the proposed method is verified.

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Antitumor Activity of New Artemisinin-Chalcone Hybrids. -A variety of new artemisinin-chalcone hybrids are designed, synthesized and tested for their antitumor activity. Compounds (Ic) and (IIc) are most active toward HeLa cells. Compounds (III) show only slight improvement compared to dehydroartemisinin. -(XIE, L.; ZHAI, X.; LIU, C.; LI, P.; LI, Y.; GUO, G.; GONG*, P.; Arch. Pharm. (Weinheim, Ger.) 344 (2011) 10, 639-647, http://dx.

Tetramethrin is a widely applied type I chiral pyrethroid insecticide that exists as a mixture of four isomers. In the present study, its stereoselective cytotoxicity, bioaccumulation, degradation, and metabolism were investigated for the first time at the enantiomeric level in detail by using a sensitive chiral high-performance liquid chromatography−tandem mass spectroscopy (HPLC-MS/MS) method. Results showed that among rac-tetramethrin and its four enantiomers, the trans (+)-1R,3R-tetramethrin had the strongest inhibition effect on the PC12 cells. In the earthworm exposure trial, the concentration of trans (−)-1S,3Stetramethrin was 0.94−8.92 times in earthworms (cultivated in natural soil) and 1.67−5.01 times (cultivated in artificial soil) higher than trans (+)-1R,3R-tetramethrin, respectively. In the greenhouse experiment, the trans (+)-1R,3R-tetramethrin and cis (+)-1R,3Stetramethrin were preferentially degraded. Furthermore, for rat liver microsome in vitro incubation, the maximum metabolism rate of cis (−)-1S,3R-tetramethrin was 1.50 times higher than its antipodes. Altogether, the aim of this study was to provide a scientific and reasonable reference for the possibility of developing a single enantiomer to replace the application of rac-tetramethrin, which could possess better bioactivity and lower ecotoxicity, and thus permit more reliable and accurate environmental monitoring and risk assessment.