Method for the fruit tree recognition and navigation in complex environment of an agricultural robot

To realize the visual navigation of agricultural robots in the complex environment of orchards,this study proposed a method for fruit tree recognition and navigation based on YOLOv5.The YOLOv5s model was selected and trained to identify the trunks of the left and right rows of fruit trees;the quadratic curve was fitted to the bottom center of the fruit tree recognition box,and the identified fruit trees were divided into left and right columns by using the extreme value point of the quadratic curve to obtain the left and right rows of fruit trees;the straight-line equation of the left and right fruit tree rows was further solved,the median line of the two straight lines was taken as the expected navigation path of the robot,and the path tracing navigation experiment was carried out by using the improved LQR control algorithm.The experimental results show that under the guidance of the machine vision system and guided by the improved LQR control algorithm,the lateral error and heading error can converge quickly to the desired navigation path in the four initial states of[0 m,−0.34 rad],[0.10 m,0.34 rad],[0.15 m,0 rad]and[0.20 m,−0.34 rad].When the initial speed was 0.5 m/s,the average lateral error was 0.059 m and the average heading error was 0.2787 rad for the navigation trials in the four different initial states.Its average driving was 5.3 m into the steady state,the average value of steady state lateral error was 0.0102 m,the average value of steady state heading error was 0.0253 rad,and the average relative error of the robot driving along the desired navigation path was 4.6%.The results indicate that the navigation algorithm proposed in this study has good robustness,meets the operational requirements of robot autonomous navigation in orchard environment,and improves the reliability of robot driving in orchard.

Adjuvant chemotherapy versus adjuvant concurrent chemoradiotherapy after radical surgery for early-stage cervical cancer:a randomized,non-inferiority,multicenter trial

We conducted a prospective study to assess the non-inferiority of adjuvant chemotherapy alone versus adjuvant concurrent chemoradiotherapy (CCRT) as an alternative strategy for patients with early-stage (FIGO 2009 stage IB–IIA) cervical cancer having risk factors after surgery. The condition was assessed in terms of prognosis, adverse effects, and quality of life. This randomized trial involved nine centers across China. Eligible patients were randomized to receive adjuvant chemotherapy or CCRT after surgery. The primary end-point was progression-free survival (PFS). From December 2012 to December 2014, 337 patients were subjected to randomization. Final analysis included 329 patients, including 165 in the adjuvant chemotherapy group and 164 in the adjuvant CCRT group. The median follow-up was 72.1 months. The three-year PFS rates were both 91.9%, and the five-year OS was 90.6% versus 90.0% in adjuvant chemotherapy and CCRT groups, respectively. No significant differences were observed in the PFS or OS between groups. The adjusted HR for PFS was 0.854 (95% confidence interval 0.415–1.757;P = 0.667) favoring adjuvant chemotherapy, excluding the predefined non-inferiority boundary of 1.9. The chemotherapy group showed a tendency toward good quality of life. In comparison with post-operative adjuvant CCRT, adjuvant chemotherapy treatment showed non-inferior efficacy in patients with early-stage cervical cancer having pathological risk factors. Adjuvant chemotherapy alone is a favorable alternative post-operative treatment.

Linear Strain-Gradient Effect on the Energy Bandgap in Bent CdS Nanowires

尽管在半导体的可能的非同类的紧张效果被调查了因为在一半上世纪和紧张坡度能每在灵活 nanostructures 的测微计是超过 1% ，我们仍然缺乏他们对精力乐队的影响的理解。这里，我们进行紧张坡度的系统的阴极射线发光光谱学研究在在低温度的有弹性地弄弯的 CdS nanowires 的导致的激子精力移动，并且发现在弄弯的 nanowires 的激子精力红移动与紧张坡度成正比，格子失真的一个索引。密度功能的计算在弄弯的 nanostructures 显示出乐队差距减小的一样的趋势并且揭示内在的机制。半导体的乐队差距上的重要线性紧张坡度效果应该在在 nanoelectronics 调节光电子的性质的方法上打开新灯。

Bending-Induced Conductance Increase in Individual Semiconductor Nanowires and Nanobelts

Reliable ohmic contacts were established in order to study the strain sensitivity of nanowires and nanobelts.Significant conductance increases of up to 113%were observed on bending individual ZnO nanowires or CdS nanobelts.This bending strain-induced conductance enhancement was confirmed by a variety of bending measurements,such as using different manipulating tips(silicon,glass or tungsten)to bend the nanowires or nanobelts,and is explained by bending-induced effective tensile strain based on the principle of the piezoresistance effect.