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According to the needs of ultrasonic vibration feeding, we developed an ultrasonic piezoelectric feeding device. The device with unrestricted length and width and the feeding speed is uniform. we analyzed feeding the boundary conditions and calculated the expression of the average feeding speed. Using ANSYS to analyze the relevant parameters of feeding vibrator, we made the piezoelectric feeding vibrator and carried out a series of experiments to test the feeding effect by using Laser Doppler vibrometry. The results showed that the amplitude of the first order longitudinal vibration is maximum when the excitation frequency is 34.7kHz; When the feeding device is at the excitation frequency and the driving voltage is 130V, the feeding effect of the heavy material with smooth surface is very good (M10×30 bolts, M20 nuts); Materials with rough surface and lighter than 0.5g have almost no feeding capacity (tablets and grains), and the feeding device has certain selectivity for materials; When the mass of material is 72g, the feeding speed can reach 60.45mm/s. The study provides a reference for the research of ultrasonic feeding device.

Cassava/peanut intercropping is a popular cultivation method in the south China, with the advantage of apparent yield increase. In order to analyze the effect of cassava/peanut intercropping on physical and chemical properties in peanut rhizosphere soil, the physical and chemical properties were investigated under the biochar application and straw mulching. The result showed that the Ph, organic materials content, available phosphorus content, available potassium content in peanut rhizosphere under the biochar application increased by 7.06%, 94.52%, 17.53%, 25.08% (monoculture peanut) and 8.47%, 89.94%, 17.93%, 22.87% (cassava/peanut intercropping) compared with Ck in the same planting patterns. In addition, the available nitrogen content, organic materials content, available phosphorus content, and available potassium content in peanut rhizosphere under the straw mulching increased by 89.80%, 60.92%, 5.95%, 9.98% (monoculture peanut) and 67.09%, 52.34%, 6.96%, 11.94% (cassava/peanut intercropping) compared with Ck in the same planting patterns. In the same treatment conditions, bulk density in peanut rhizosphere soil decreased and porosity and saturated permeability coefficient increased slightly. But there was no significant difference between the two. At the same time, cassava/peanut intercropping could increase soil nutrients. Therefore, it is beneficial to apply biochar and straw mulching, and the suitable intercropping row spacing is more beneficial to increase soil nutrient contents.

The growth of Ge quantum dots (QDs) using the ion beam sputtering deposition technique has been successfully conducted directly on single-layer graphene supported by SiO2/Si substrate. The results show that the morphology and size of Ge QDs on graphene can be modulated by tuning the Ge coverage. Charge transfer behavior, i.e. doping effect in graphene has been demonstrated at the interface of Ge/graphene. Compared with that of traditional Ge dots grown on Si substrate, the positions of both corresponding photoluminescence (PL) peaks of Ge QDs/graphene hybrid structure undergo a large red-shift, which can probably be attributed to the lack of atomic intermixing and the existence of surface states in this hybrid material. According to first-principles calculations, the Ge growth on the graphene should follow the so-called Volmer-Weber mode instead of the Stranski-Krastanow one which is observed generally in the traditional Ge QDs/Si system. The calculations also suggest that the interaction between Ge and graphene layer can be enhanced with the decrease of the Ge coverage. Our results may supply a prototype for fabricating novel optoelectronic devices based on a QDs/graphene hybrid nanostructure.

A new compound of overall composition NdCo8B3Si with a tetragonal structure has been synthesized by arc-melting, and identified by X-ray powder diffraction and analytical electron microscopy.

In rare-earth (R) intermetallics, the molecular field coefficient nRR describing exchange interactions between R spin moments decreases, in a given series, by almost an order of magnitude from compounds with light R to those with heavy R elements. Simultaneously a decrease is observed in the transferred hyperfine field at nonmagnetic sites. These results are compared to the recent observation in R-transition metal (M) compounds of a decrease of the molecular field coefficient nRM across a given series of compounds (M fixed, R varied). These behaviours are coherently understood by considering that both R-R and R-M indirect exchange interactions in R intermetallics occur via 5d conduction electrons and that the 4f-5d exchange at R sites decreases from Pr to Tm.

A new method for the determination of crystal field and exchange parameters in rare-earth/transition-metal compounds, involving the analysis of magnetisation curves, is described. Rather than trying to reproduce directly the magnetisation curves by computer diagonalisation using crystal field and exchange parameters, the method uses experimentally determined anisotropy constants. These constants are parameters which reproduce the magnetisation curves but to which no special physical significance is attached. The energy expansion in terms of these anisotropy constants allows one to avoid long iterative computing. Application of this method to Nd2Fe14B results in an excellent description of the complex magnetic behavior of this compound.