气力输送技术在农业机械中的应用

气力输送技术可在很大程度对农业机械进行结构简化,降低成本和提高作业效率,越来越多地被用于播种、施肥和捡拾收获等物料输送装置中。了解气力输送技术的特性以及在农业机械中的应用现状,对于提高农机作业效率、促进先进农业机械化技术研发具有重要意义。为此,在农业物料气力输送特性、气力输送技术在农机领域的应用情况等方面进行大量文献调研分析和归纳总结。根据正负压输送的不同特点,对气力播种、施肥、收获捡拾机械装备的主要结构、工作原理和特点进行分析和阐述。在此基础上,指出农业领域气力输送应用和研究中存在的问题,包括：气力输送方式存在易堵塞、精度稍低的问题,能耗较大的问题以及相关基础研究不足的问题。针对以上存在的问题,提出针对性的建议：优化结构、配套监测系统,提高工作可靠性;改用效率较高的智能风机,降低能耗;加强基础研究,充分利用仿真等研究手段,进一步促进气力输送技术的应用。     

融合路面特征的大型喷雾机多工况悬架控制与试验

大型高地隙喷雾机的作业工况复杂,不同路况对悬架的性能要求不尽相同,传统悬架系统已无法满足喷雾机多工况作业的不同减振需求。为有效提高大型喷雾机各工况下的减振性能并有效降低能耗,提出了一种基于路况识别的多工况主动悬架控制系统。首先,分析喷雾机典型作业工况,建立路面特征与悬架模型的映射关系;然后,搭建喷雾机油气悬架的上下层控制系统,采用变步长萤火虫算法优化控制系统中各工况下的阻尼系数;最终将搭载该控制算法的喷雾机进行田间动态性能试验。试验结果表明,相比传统悬架,主动悬架在水泥及田间路面的行驶平顺性分别提升11.0%和22.8%,操控稳定性分别提升24.5%和3.4%。本研究所提出的控制系统可以有效解决不同工况下驾驶平顺性和操纵稳定性的矛盾关系,满足喷雾机各工况的特定减振需求。     

Effect of fibers on the flow property of turbulent fiber suspensions in a contraction

In the flow of turbulent fiber suspensions flowing through a contraction with rectangular cross-section, the Reynolds averaged Navier-Stokes equation with the term of additional stress resulting from fibers was solved with the Reynolds stress model to get distributions of the mean velocity, mean pressure, turbulent kinetic energy and turbulent dissipation. It is found that the mean velocities at exit are small around the center and large near the wall for higher concentration. Fibers reduce turbulent intensity and turbulent dissipation at central line, but enhance them over the cross section at exit. Fibers have no effect of restraint on the turbulence in the contraction flow. The additional stress resulting from fibers plays a role in the increase of drag.     

马铃薯清选机气力悬浮薯石分离装置设计与试验

针对以联合收获为主的北方马铃薯主产区,马铃薯收获后薯石分离人工捡拾工作量大、清选效率低,且清选洁净率较低等问题,利用薯块和石块密度不同的特点,采用气力悬浮输送技术设计了马铃薯清选机气力悬浮薯石分离装置,并基于该装置研究了不同参数调整条件下的清选特性。利用高速气流悬浮与振动筛的摆动作用,发挥气力悬浮和振动筛分离的双重优势,使薯块与石块在运动过程中实现自动分离。试验表明：当气流速度为35m/s、筛面倾角为18°和曲柄角速度为30rad/s时,马铃薯选出率均值为96.71%,清选洁净率均值为98.34%,各项性能指标均满足马铃薯清选作业要求。     

基于代码生成的电控空气悬架系统电子控制单元

为提高某型SUV车辆的行驶平顺性、通过性等,对其进行空气悬架改装,并设计了由最小系统、车速信号调理模块、电动气泵控制模块、组合电磁阀控制模块、车身高度检测模块、CAN总线模块、车身加速度测量模块等组成的以Freescale XDP512为核心芯片的电控空气悬架系统电子控制单元,利用Real-Time Workshop(RTW)代码生成技术将所制定电控空气悬架系统控制策略转化为ANSI C代码并下载至电子控制单元,然后对安装电控空气悬架系统的试验车辆进行了车身高度与车速耦合试验、转向试验、急加速试验、急减速试验、平顺性试验,结果表明所设计的电控空气悬架系统控制单元能够实现车速信号调理、车身高度与车速耦合、电动气泵控制及组合阀控制等功能。     

Behavioural interactions of seabirds with suspended mussel longlines

Increased abundances of a number of seabird species have been found in areas of mussel longline aquaculture (compared to control sites) in a recent study at Bantry Bay, southwest Ireland. The aim of this study was to investigate whether this form of mussel aquaculture also affects the activity budgets and foraging behaviour of these seabirds. Scan-sampling was used to compare seabird activity budgets between three areas of mussel longline aquaculture and three control sites. Foraging activities of Great-Northern Divers Gavia immer, an Annex 1 species under the Euopean Union's Birds Directive, were also compared between sites using focal sampling. The behaviour of gulls (Larus sp.), Cormorants Phalacrocorax carbo, Shags Phalacrocorax aristotelis and Great-Northern Divers (but not auks, Alcidae) differed significantly between areas of mussel aquaculture and control sites in this study. Mussel suspension buoys were heavily utilized by gulls, cormorants and shags as safe perching platforms for preening activities. Gulls also fed extensively on epifauna attached to the buoys. Great-Northern Divers spent more time snorkelling (head submerged in search of food) in mussel sites than in the control sites, however dive duration and visible foraging success rates did not differ significantly between sites. Overall, the environmental impact of mussel suspension culture appears to be positive or neutral on marine bird species occurring at this study site.     

Cytotoxicity of surfactants to the FHM-sp cell line

Cytotoxicity of eight surfactants was determined by the neutral red assay with the fathead minnow (FHM)-sp cell line, a cell line in suspension culture from fish. The toxicity ranking of the surfactants was benzalkonium chloride > benzethonium chloride > sodium linear - dodecylbenzene–sulfonate (LAS) > potassium laurate > sodium dodecylsulfate > polyoxyethylene(20)sorbitan monolaurate > polyoxyethylene(20)sorbitan monooleate > betaine. The toxicity ranking of the surfactants classified into four groups based on the ion of the hydrophilic group was cationic surfactants > anionic surfactants > non-ionic surfactants > amphipathic surfactants. The FHM-sp cells, as well as the chinook salmon embryo (CHSE)-sp cells, could be inoculated directly to the microplate wells without dispersion by trypsin treatment of cell sheets at room temperature. Therefore, the cytotoxicity assay of the surfactants could be carried out quickly by using the FHM-sp cell line. The FHM-sp cell line had similar or higher sensitivity to sodium dodecylsulfate compared with several cell lines from mammals. The cytotoxicity assay could be shortened by the procedure exposing the surfactants to the FHM-sp cells before the cell monolayer formation in the microplate wells. To use the FHM-sp cell line as a screening tool prior to in vivo testing, studies on the correlation between in vivo data and in vitro data on the toxicity of surfactants are necessary.     

FSAE赛车悬架系统的设计及分析

根据FSAE大赛规则要求,对赛车悬架系统的类型进行了选择,并对其进行了设计,确定了悬架的基本参数,在此基础上,在CATIA软件中建立了悬架总成的三维模型,对其关键零件前悬架摇臂进行了有限元分析,结果表明,其强度满足要求,对实车的制造提供了一定的参考.     

辛硫磷和毒死蜱微囊悬浮剂释放机制及其主要影响因素研究

[目的]明确辛硫磷微囊悬浮剂和毒死蜱微囊悬浮剂的主要释放机制和影响因素。[方法]利用液相色谱分析方法,测定2种微囊悬浮剂在2种湿度、温度和通风状态下的土壤释放(消解)动态。[结果]在35℃干燥土壤中,辛硫磷微囊悬浮剂吹风处理的T0.5是2.2 d;而密闭处理的T0.5是859.2 d。在35℃吹风条件下,辛硫磷微囊悬浮剂和毒死蜱微囊悬浮剂在干燥土壤和水饱和土壤中的T0.5分别是2.2和5 800 d;8 d和206.1 d;而当温度为35和25℃(其他条件相同)时,前者的T0.5分别是2.2和18.6 d;后者的T0.5分别是8.0和28.8 d。[结论]辛硫磷微囊悬浮剂和毒死蜱微囊悬浮剂释放机制都是以气化释放为主;湿度和温度是影响两者释放的最主要因素。     

5％氟虫腈悬浮种衣剂拌种防治玉米田蛴螬效果及使用技术

[目的]了解5％氟虫腈悬浮种衣剂拌种防治玉米田蛴螬的效果,为该制剂的进一步推广应用提供参考.[方法]通过小区试验研究了5％氟虫腈悬浮种衣剂拌种对玉米田蟒螬的防治效果、最佳使用剂量及安全性.[结果]5％氟虫腈悬浮种衣剂玉米拌种后播种是防治玉米田蛴螬的较好药剂,建议每100kg种子用5％氟虫腈悬浮种表剂2 000 ～3 000 ml进行机械或人工拌种,田间蛴螬常年发生较重田块,100 kg种子可用5％氟虫腈悬浮种衣剂4 000 ml进行拌种,拌种时按100 kg种子所用药量用水2L的比例稀释,将药剂和种子拌匀放阴凉通风处稍晾后即可播种.[结论]为玉米田蛴螬的防治提供了理论依据.