黑龙江省农用植保无人机运营作业服务现状综述

农用植保无人机作为一种先进的新型农机装备已在黑龙江省的农业生产中得到快速普及和应用,其市场保有量已达到2万余台,飞播飞防飞施作业面积迅猛增长,前景广阔。黑龙江省是农业大省,无人机的保有量占全国总量的40%以上。为此,通过实地调研及时获知目前黑龙江省农用植保无人机的市场运营和作业服务现状,并对后期的发展做出前景展望,以利相关产业政策的制定,更好地服务于“三农”事业。

我省农机科技创新及发展趋势

农业的根本出路在于机械化，农业机械化是农业生产力的重要组成部分，是农业生产力发展的重要标志，是促进农业现代化的动力。近年来，随着国家和我省相继实施了一系列强省惠农的政策，进一步激发了农民对新机具的渴望和新农艺、农机创新的认可。黑龙江省认真贯彻落实科学发展观，以科技创新为动力，不断强化农机科技创新与推广工作，有效推动了全省农机化事业又好又快发展。省农委立足省情，针对当地土壤、水文、气候等自然环境，把农业发展、技术提升作为工作的重中之重，逐步摸索出一套适合当地完整的农机科技创新技术体系。

BZ-6播种机各部位的调整方法

详细论述了播种机各部位的调整方法,对提高播种质量、作业效率、延长使用寿命有着至关重要的作用。

Influence of Downstream Flow on Conduction Phase of Coaxial Plasma Opening Switch

Plasma behaviour and the scaling relations in a coaxial plasma opening switch （POS） using hydrogen plasma are studied self-consistently based on the two-dimensional magnetohydrodynamic （MHD） equations in conjunction with the generalized Ohm＇s law. The vacuum region on the right of POS is included in the model and the influence of downstream flow on the conduction characteristics is discussed. It is found that with the penetration of magnetic field, the pure hydrogen plasma is pushed downstream significantly; and POS still conducts current after the magnetic field arrives at the load edge of POS, which is different from the previous experimental results in a multispecies POS. It is because that the noticeable downstream plasma in the pure hydrogen POS may continue to conduct the current, while in the multispecies POS, the downstream plasma is unimportant so that the conduction phase ends soon after the magnetic field reaches the load edge. The scaling relation obtained from the simulations including the downstream region is consistent with the experimental results.

细长轴车削加工的注意事项

细长轴本身刚度较差，在车削加工时极易产生弯曲变形和振动，车削难度大，保证精度难。在通常情况下使用中心架或跟刀架来提高轴的刚度，减小轴的弯曲变形，车削时尽量采用反走刀。对于精度要求不高的细长轴还可以调头车削；有的工件过于细长，或因其它原因不能先车出一段支承面，可以采用外固定辅助套筒的方法，用千分表校正套筒，中心架支承套筒进行车削。