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This paper presents the design approach for 3-DOF (degrees-of-freedom) reconfigurable planar parallel mechanism (RPPM) with modular kinematic limbs and hybrid platform. Using the proposed approach, a series of kinematic models with rotatability are obtained. At first, the main models of PPMs are constructed. Then a series of configuration models of PPM modules are reconstructed. And the new configuration families of 3-DOF PPMs are obtained. Finally, the motion trajectories of three driven layout configurations are simulated, and the results show that the hybrid-loop platform can expand the workspace of PPM. Especially, the configurations of the PPM can transform from the two operations modes to the original mode.

The variation in the number of extreme low‐temperature days (NELD) during winter over China is examined. The NELD mainly has a significant decreasing trend across China. The leading NELD empirical orthogonal function (EOF) mode also shows consistent change characteristics over China, and a Mann–Kendall (MK) test of its time coefficients indicates that the NELD abruptly changed in approximately 1980. The impact of sea ice concentrations in the Arctic Ocean on the NELD is investigated. Sea ice concentration declines in the Barents Sea and the sea east of Greenland have significant negative effects on the NELD. Sea surface temperatures in these regions are negatively correlated with the NELD. The study analyses the influence mechanism by researching the composite atmosphere variable anomalies between years with below‐normal NELD and those with above‐normal NELD. [ABSTRACT FROM AUTHOR]

In order to develop the suitable technology for seedling nursery and increase the yield of mechanical transplanting middle-season indica hybrid rice, the experiment of two factors of uniconazole and sowing density was conducted in plastic tray seedling nursery using the variety 'Huiliangyou 6', and then the effects of uniconazole and sowing density on seedling quality, transplant quality and yield of rice were researched. The results showed that the seedling quality decreased rapidly with the increasing of sowing density in the same chemical regulation treatment. There existed a decreasing trend in the number of roots, dry weight per 100 plants, basal stem width and root vigor. Meanwhile, the MDA content of seedling leaf was significantly increased. There was no significant difference in seed setting rate and 1 000-grain weight among the different sowing density treatments. The number of effective panicles showed an increasing trend within the sowing density range from 8 000 to 18 000 grains.m-2, but decreasing from 18 000 to 30 000 grains.m-2. Finally, the yield of rice displayed the same trend as the number of effective panicles. The yield of 18 000 grains.m-2 treatment was significantly higher than that of other treatments. There existed significant effects of uniconazole on seedling quality and yield of different sowing density. The method of soaking seeds with 100 mg.L-1 uniconazole and spraying seedling leaf with 150 mg.L-1 uniconazole in 2.5 leaf age was better than the other chemical regulation method and control. It not only significantly increased the seedling quality and transplant quality, but also promoted seedling turn green and increased the number of effective panicles, grains per pancile and seed setting rate significantly, so that the yield was significantly increased. Accroding to the characters of mechanical transplanting middle-season indica hybrid rice, soaking seeds with 100 mg.L-1 uniconazole and spraying seedling leaf with 150 mg.L-1 uniconazole in 2.5 leaf age combined the sowing density of 18 000 grains.m-2 was the better seedling nursery method. It can help to keep great seedling quality, transplant quality, and stabliz 1 000-grain weight and increase the number of effective panicles, grains per pancile and seed setting rate. The sink and its effective filling rate were significantly enhanced. Finally, the yield was significantly increased. [ABSTRACT FROM AUTHOR]

The measurement of cutting force is an effective method for machining condition monitoring in intelligent manufacturing. Titanium nitride films and silicon nitride films were prepared on 304 stainless steel substrates by DC-reactive magnetron sputtering and plasma-enhanced chemical vapor deposition (PECVD). The effects of substrate negative bias and nitrogen flow on the surface microstructures of TiN film were investigated. The smoothness of the film is optimal when the bias voltage is −60 V. X-ray diffraction (XRD) analysis was performed on the samples with the optimal smoothness, and it was found that when the nitrogen flow rate was higher than 2 sccm, the titanium nitride film had a mixed phase of TiN(111) and (200). It is further revealed that the change of peak intensity of TiN(200) can be enhanced by nitrogen flow. Through atomic force microscopy (AFM), it is found that the stronger the intensity of the TiN (200) peak, the smoother the surface of the film is. Finally, the effect of different film thicknesses on the hardness and toughness of the TiN/Si3N4 film system was studied by nanoindentation experiments. The nanohardness (H) of the TiN/Si3N4 film can reach 39.2 GPa, the elastic modulus (E) is 480.4 GPa, the optimal toughness value (H3/E2) is 0.261 GPa, and the sample has good insulation performance. Linear fitting of the film's toughness to nanohardness shows that TiN/Si3N4 films with higher hardness usually have a higher H3/E2 ratio. [ABSTRACT FROM AUTHOR]