Design and experiment of the side insertion horizontal transplanting device for sweet potato(Ipomoea batatas Lam.)seedlings on mulch film

Side insertion horizontal transplanting sweet potato seedlings on mulch film is one kind of new planter pattern,which keeps the soil warm and moist restraining the infestation of pests and weeds,realizing dense transplanting and ensuring uniformity of sweet potato sizes.Therefore,a side insertion horizontal transplanting device for sweet potato seedlings on mulch film was designed,including the details and parameters of the reciprocating mechanism and the seedling clamping mechanism.Both the two mechanisms and the whole device were simulated and the test bench was built for field experiments to detect if this device can meet the agronomic requirements.The simulation results show that the designed device is in accordance with the agronomic requirements of horizontal transplanting,transplanting depth and transplanting length,and is potential for achieving rational close planting.The lateral length of the designed transplanting device is extended at about 90 mm compared with previous machine,which will promote the number of soil nodules of sweet potato seedlings and the growth of production enormously.The horizontal velocity of the transplanting claw is−17 mm/s when picking the seedling,the horizontal velocity of the transplanting claw 645 mm/s and the vertical velocity 83 mm/s when releasing the seedling.These data could ensure the accuracy requirements of horizontal transplanting trajectory.The field experiment results show the expulsion rate of sweet potato seedlings at 1.38%,the qualified rate of transplanting length and depth at 94.17%and 95.11%respectively,the average length and width of the mulch film breaking hole at 44.67 mm and 43.00 mm in several.The postures of the actual transplanted seedlings are consistent with the simulation results,meeting the requirements of horizontal transplanting with less damage to the mulch film.The designed transplanting device lays a foundation for the development of sweet potato seedlings side transplanting machine.

间歇性外斜视儿童视觉功能及阅读学习障碍临床分析

目的:比较间歇性外斜视(IXT)患者与眼位正常儿童在双眼视功能、发生阅读学习障碍方面的差异并分析其相关性。方法:前瞻性临床研究。采用随机数字抽样法收集2021年7月至2022年3月在广州市妇女儿童医疗中心眼科门诊就诊的IXT儿童(39例,作为IXT组)和眼位正常儿童(44例,作为对照组)。检查并记录2组性别、年龄、最佳矫正视力(BCVA)、等效球镜度(SE)、远近水平眼位、集合近点、近立体视、调节幅度、单双眼调节灵活度,完成《儿童汉语阅读障碍量表》和《儿童学习障碍筛查量表》。使用独立样本t检验、非参数检验法差异性检验(曼-惠特尼法)、卡方检验、K-W检验、Spearman相关系数对数据进行统计分析。结果:IXT组与对照组性别、年龄、BCVA、SE比较差异无统计学意义(均P>0.05)。2组儿童远近眼位、近立体视、集合近点、双眼调节灵活度差异均有统计学意义(均P<0.001)。调节幅度和单眼调节灵活度在2组中差异无统计学意义(P>0.05)。IXT组的年龄组间各指标差异无统计学意义(P>0.05)。IXT组和对照组在阅读障碍发生率和学习障碍评分方面差异有统计学意义(χ^(2)=8.45,P=0.004;t=-4.07;P<0.001)。阅读障碍与远近水平眼位、近立体视、集合近点、双眼Flipper检查结果和学习障碍评分显著相关(r=-0.43、-0.37、-0.57、0.41、-0.54、-0.62,均P<0.05)。结论:IXT患儿与眼位正常儿童相比,存在部分双眼视觉功能异常,容易出现阅读困难及学习障碍。