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Six new polyketides including four oxepinochromenones, conioxepinols A-D (1-4), one furochromenone, coniofurol A (5), and one xanthone, conioxanthone A (6), have been isolated from the crude extract of the endolichenic fungus Coniochaeta sp. The absolute configurations of C-7 in 1 and the 7,8-diol moiety in 3 were assigned using the modified Mosher's and(More)
A novel ultrasonic levitating bearing excited by three piezoelectric transducers is presented in this work. The transducers are circumferentially equispaced in a housing, with their center lines going through the rotation center of a spindle. This noncontact bearing has the ability to self-align and carry radical and axial loads simultaneously. A finite(More)
Mitochondrial DNA (mtDNA) has been widely used in species identification and genetic diversification. Comparisons among mtDNAs of closely related species are valuable for phylogenetic studies. However, only the partial mtDNA Cytb gene and the D-loop sequences were used to analysis the phylogenetic relationship between donkey breeds due to lack of complete(More)
Conventional ultrasonic drills can drill into rocks using high frequency axial vibration, which feature lower power and lower preload force, thus they could become a very attractive solution for future deep-space exploration. However, drill cuttings cannot be removed effectively with the increase of drilling depth by conventional ultrasonic drills that only(More)
The posture-adjustable turntable is playing an important part in testing equipments and other industrial devices. As well known, universal joint is employed to couple two parts that are aligned with a certain angle to transmit torque and speed. There are three major parts in a U-joint: active hinge, cross shaft, and passive hinge. Power is transmitted from(More)
China is launching the lunar exploration mission, namely "Chang'e" project. In the third phase of the project, a probe will be sent to the moon to acquire the lunar regolith through automated drilling device. The drilling sample is expected to be sealed into a storing container which will be brought back to the earth by return capsule. Drilling sample(More)
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