Structure design and fabrication for resonant accelerometer based on electrostatic stiffness

The introduced resonant accelerometer makes use of the equivalent electrostatic stiffness to sense the acceleration. The sensitivity can be adjusted by changing the applied sensing voltage and it is robust for the fabrication error. According to the sensing principle,the dynamic model of the single beam accelerometer is built along with the no-linear relationship of the output frequency and the displacement of all positive components. When the stiffness of the vibrating beam is much bigger than the stiffness of the fold beam, the sensitivity can effective achieve. It is the restriction for the structure design. For the differential structure, mode analysis shows it is a lower mode in plane for the work mode. Decreasing the stiffness of connected end for the double vibrating beam can reduce the disturbance error. The bulk micromachining for the resonant accelerometer can achieve high depth width ration etching. The experiment find the structure is not broken and there is the same frequency disturbance problem. FM is suggested to deal with the disturbance. Theory analysis and test provides some important conclusions for the design of the novel type resonant accelerometer.     

马铃薯在高压静电场中冻结后贮藏的试验研究

微能源在食品工业中的应用日益广泛。本文对不同高夺静电场强冻结的马薯在－20℃下贮藏的品质变化进行了实验研究。研究发现：无电场冻结的样品的质地在相同的贮藏期内最差；经较低场强冻结的样品之间的质地特性差别不大，但较无电场冻结的要高；经强电场250kV/m冻结的样品的质地较好。在较低场强下冻结的样品的持水能力较无电场冻结的要差；经250kV/m电场处理的样品失水率低，品质较好。     

除草剂变量施药技术的研究现状与进展

除草剂的田间大面积均匀喷洒不仅造成了浪费,而且加剧了环境污染,作为精确农业关键技术的除草剂的变量施药能够精确地对准杂草喷洒除草剂,从而有效地减少除草剂用量,降低了农业生产成本、减轻了环境污染压力。文章介绍了基于颜色、形状、纹理、光谱、位置特征的计算机视觉杂草识别技术;给出了变量施药技术的概念和介绍了变量施药技术的国内和国外的研究概况,并探讨了该技术的实施难点和未来研究发展方向。     

OS-施特灵的防病效果及其防病机理初探

采用灌根和叶面喷施2种处理,调查病害的发生情况.研究结果表明,OS-施特灵对番茄、茄子、黄瓜和辣椒的主要真菌病害具有较好的防治效果;通过不同浓度的OS-施特灵对几种病原真菌的菌丝生长和孢子萌发作用的试验,结果表明,OS-施特灵对病原菌孢子萌发和菌丝生长具有明显的抑制作用.     

M增产素对小麦抗旱性的影响

通过Ｍ增产素对小麦进行浸种和抽穗开花期喷洒处理，重点研究了对小麦后期水分生理指标、叶绿素含量、外渗电导值以及产量等的影响．结果表明，处理明显地改善了小麦的水分状况、降低了电解质外渗率，有明显的保绿作用，防止叶片早衰、增产效果显著。     

电除尘器中供电方法的研究

对电除尘器中的恒定火花率供电以及最佳工作点探测供电进行剖析，从中找出几种烟尘条件下的控制方案，使之工作在最佳状态。     

高压静电场对老化水稻种子活力的影响

用高压静电场处理吸水萌动的老化水稻种子,研究了高压静电场对种子活力的影响。结果表明,老化水稻种子经高压静电场处理后,发芽率、发芽指数、幼苗干重、活力指数比对照显著增加;高压静电场处理还显著提高了幼苗根系活力、叶绿素含量、淀粉酶活性;经高压静电场处理后种子浸出液电导率比对照组显著下降。而且高压静电场处理55 min幼苗淀粉酶活性、种子浸出液电导率、叶绿素含量都优于处理30 min。可见适宜的高压静电场处理可以提高老化水稻种子的活力,促进种子的生长发育。     

果树树冠静电喷雾的空间电荷效应分析

以风送静电喷雾机为例,描述了杀虫剂药液被气流剪切式喷嘴雾化时雾滴的诱导充电过程,建立了一个树冠静电喷雾过程的电子—机械简化模型,用于分析雾滴沉积过程中作用于荷电雾滴的静电力(镜像力、空间电荷力和空间电荷引力)和机械力(重力和拉力)。静电力的相对大小是通过与机械力的力比值作比较的,50μm和100μm两种充电雾滴的典型的力比值说明空间电荷引力在雾滴沉积过程中起着重要的作用。     

叶面喷施硒肥对烤烟的影响

通过大田叶面喷施硒肥试验,研究了硒肥对烤烟生长、叶绿素含量、烟叶硒含量等的影响。结果表明：硒肥有促进烟株生长的作用,施用硒肥时间越早,促进作用越大。第5叶的叶绿素a、叶绿素b、叶绿素a＋b、类胡萝卜素含量,喷施硒肥的处理极显著大于对照;第10叶的叶绿素a含量喷施硒肥的处理显著大于对照;第14叶的叶绿素a含量喷施硒肥的处理显著小于对照。喷施硒肥时期越迟,叶片平均硒含量越高。叶面喷施硒肥的利用率为1.41%-3.27%,平均为2.37%。     

The Economic Impact of Site-Specific Weed Control

In order to evaluate economic and ecological benefits, site-specific weed control was realised in a 4-year experiment on five fields with a GPS-guided sprayer. An average of 54% of the herbicides could be saved. Savings were strongly dependent on crop and year. For grass weed herbicides, the savings were 90% in winter cereals, 78% in maize, and 36% in sugar beet. For herbicides against broadleaf weeds, 60% were saved in winter cereals, 11% in maize, and 41% in sugar beet. The monetary savings resulting from the reduction in herbicide use varied between the crops, depending on the amount of herbicides saved and the price of the herbicides. In maize, savings of 42euro/ha were realised, in winter wheat of 32euro/ha, in winter barley of 27euro/ha and in sugar beet of 20euro/ha. Large sections of the fields needed herbicide treatment significantly less frequently. In those areas where weed density remained below the weed control threshold, flora and fauna were allowed to establish largely without disturbance.