A Novel Robot of Manufacturing Space Solar Cell Arrays

This paper presents a novel robot employed to manufacture space solar cell arrays. First of all including the mechanical configuration and control system, the architecture of the robot is described. Then the flow velocity field of adhesive in the dispensing needles is acquired based on hydrodynamics. The accurate section form model of adhesive dispensed on the solar cells is obtained, which is essential for the robot to control the uniformity of dispensing adhesive. Finally the experiment validates the feasibility and reliability of the robot system. The application of robots instead of manual work in manufacturing space solar cell arrays will enhance the development of space industry

How Stand Age Affects Soil Nitrification and Nitrogen Gas Emissions in Tropical and Subtropical Tea Plantations

Tea plants prefer NH4+-N to NO3−-N, and thus nitrification would be detrimental to the N uptake of tea. However, the effects of different stand ages on nitrification and nitrogen oxide (NO and N2O) emissions in tropical and subtropical regions remain unclear. We performed an incubation experiment with tea field soils from different stand ages (5, 15, and 30 years) under different water contents in subtropical (Changsha, Hunan; C5L, C15L, C30L, C5H, C15H, C30H) and tropical regions (Baisha, Hainan; B5L, B15L, B30L, B5H, B15H, B30H). The results showed that the highest net nitrification rate was in C15L and B15. The results indicated that there was more NO3−-N loss in the 15-y tea field soil in both regions. The highest nitrogen oxide emissions from the subtropical and tropical plots were in C15H and B30H. Available K was the key variable for NO and N2O emissions in Changsha county, whereas SOM, pH, and available P were the key factors affecting NO and N2O emissions in Baisha county. Our findings suggest that more attention should be paid to NO3−-N loss in middle-aged (10–30 years) tea fields. Similarly, the focus should be given to nitrogen oxide emissions from middle-aged tea plantations in subtropical regions and old tea plantations (≥30 stand years) in tropical regions

Bias Stability Investigation of a Triaxial Navigation-Compatible Accelerometer with an Electrostatic Spring

The bias stability performance of accelerometers is essential for an inertial navigation system. The traditional pendulous accelerometer usually has a flexible connection structure, which could limit the long-term bias stability. Here, based on the main technologies employed in previous space missions of our group, we developed a terrestrial triaxial navigation-compatible accelerometer. Because there is no mechanical connection between the inertial test mass and the frame, the bias performance relies on the stability of the equivalent electrostatic spring, where further sources are analyzed to get the optimal electrostatic force scheme. To investigate the bias stability under different ranges, the vertical and horizontal measurement ranges are designed at 5 g and ±10 mg, respectively. A low-noise high-voltage levitation scheme is adopted to extend the vertical measurement range from sub-mg to more than earth’s 1-g gravity. Finally, the experimental validation results show that the 24-h bias stability of vertical and two horizontal directions come to 13.8 μg, 0.84 μg, and 0.77 μg, respectively

Which Is Better in Clinical and Radiological Outcomes for Lumbar Degenerative Disease of Two Segments: MIS-TLIF or OPEN-TLIF?

Objective: To compare the clinical and radiological outcomes of minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) and traditional open transforaminal lumbar interbody fusion (OPEN-TLIF) in the treatment of two-level lumbar degenerative diseases. Methods: The clinical data of 112 patients were retrospectively analyzed, and were divided into an MIS-TLIF group and OPEN-TLIF group. The operative time, intraoperative fluoroscopy, blood loss, postoperative drainage volume, bed rest time, the content of creatine kinase(CK) and complications, were recorded. VAS score and ODI index were used to evaluate clinical efficacy. Bridwell grading was used to evaluate postoperative interbody fusion. Screw position was evaluated by Rao grading. Results: Compared with the OPEN-TLIF group, the MIS-TLIF group had longer operation times, more intraoperative fluoroscopy times, but shorter postoperative bed times (p p > 0.05). There was no difference in VAS score and ODI index during the follow-up (p > 0.05). There was no significant difference in the interbody fusion rate between the two groups (p > 0.05). There was no significant difference in the distribution of type A screws, but the type B screw in the MIS-TLIF group was higher (p p > 0.05). Conclusion: The postoperative quality of life score and radiological outcomes of the two types of surgery in two-level lumbar degenerative diseases was similar, and there was no significant difference in muscle injury and complications, but the operation time and intraoperative radiation exposurewere higher than in the OPEN-TLIF group, and the pedicle screws were more likely to deviate laterally out of the vertebral body. Therefore, OPEN-TLIF is recommended for patients with lumbar degenerative diseases of two segments