Nanostructured liquid crystalline particle assisted delivery of 2,4-dichlorophenoxyacetic acid to weeds,crops and model plants     

《Crop Protection》2016

Routine agricultural practices are heavily dependent on the use of surfactants, many of which are toxic to humans and detrimental to the environment. In proof of concept work we have previously shown the potential of nanostructured liquid crystalline particles (NLCP) to safely interact with plant leaf cuticular surfaces with minimal impact on epicuticular waxes. Here we demonstrate the use of NLCP to effectively deliver the auxin herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) to plant leaves in laboratory and field studies. In the laboratory, the physiological stress responses of lupin, Lupinus angustifolius (L.) (Fabaceae) towards NLCP spray applications were shown to be much reduced in comparison with application of two common surfactants. Phytotoxicity assays of 2,4-D loaded NLCP were used to validate the herbicidal effects on Arabidopsis thaliana (L.) Heynth. (Brassicaceae) and established a similarity with that of surfactant assisted 2,4-D delivery when tested at a concentration of 0.1%. Field trials were conducted to test the efficacy of NLCP-assisted delivery of 2,4-D in comparison with commercial surfactants for the control of the invasive weed wild radish, Raphanus raphanistrum (L.) (Brassicaceae), in wheat, Triticum aestivum (L.) (Poaceae) crop fields. Compared against Estercide 800, a commercially available 2,4-D formulation, NLCP assisted delivery of 2,4-D was effective at low concentrations of 0.03% and 0.06%. The crop yield remained similar for all the tested concentrations and formulations of 2,4-D loaded NLCP and Estercide 800. This is the first report to directly show that, as an alternative to conventional methods, NLCP can be used under both laboratory and field conditions to successfully delivery an agrochemical.  相似文献   

Effects of endurance racing on horse plasma extracellular particle miRNA     

Getúlio P. de Oliveira Jr  William F. Porto  Cintia C. Palu  Lydyane M. Pereira  Alessandra M. M. Reis  Tatiana G. Marçola  Antonio R. Teixeira-Neto  Octavio L. Franco  Rinaldo W. Pereira 《Equine veterinary journal》2021,53(3):618-627

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硅颗粒对Al-Si合金显微组织的影响     

陈刚  王宁  孙琴 《农业机械学报》2006,37(6):144-147

通过在不同温度下向亚共晶AlSi合金熔体中加入固体Al20%Si(质量分数)合金,研究了初生硅颗粒对Al7%Si合金显微组织产生的影响。结果表明:随着处理温度的降低,显微组织从树枝状α相加含针状硅的共晶相,转变成球形α相加含短针状硅的共晶相,最后变成硅颗粒加粗化的球形α相和更少的共晶相。当选择合适的Al20%Si合金组织和处理温度时,采用该工艺可有效地制备半固态成形用坯料。结合初生硅颗粒在亚共晶AlSi合金熔体中的变化过程,对Al7%Si显微组织的演化机理进行了分析。  相似文献   

锥-板环形水槽的研制及其在颗粒起动试验中的应用     

洪安宇  王正中  赵延风 《农业工程学报》2015,31(22):77-82

在颗粒起动观测试验中,传统长直型水槽及环形水槽试验无法观测流体长期作用下的颗粒运动,依据锥-板转子流变仪原理,设计了一种锥-板环形水槽装置;采用无量纲拖曳力作为起动时的流体力学指标,结合CCD(电荷耦合组件,charge coupled device)成像技术及PIV(粒子图像测速,particle image velocimetry)技术,运用该装置对层流时无黏性均匀颗粒在流体长期作用下的运动形态及起动规律进行了观测,观测发现流体长期作用下颗粒的起动为连续的起动过程,存在2个不同的临界状态,分别为初始临界状态和饱和临界状态,初始临界状态下的起动拖曳力和经典Shields曲线的取值基本一致,饱和临界状态下的起动拖曳力明显高于Shields曲线的取值,表明锥-板环形水槽是一种合理有效的颗粒起动观测装置,特别适用于流体长期作用下的颗粒起动规律研究。  相似文献   

植物–微生物联合对土壤不同粒径组分中 PAHs 的修复作用     

周妍  滕应  姚伦芳  任文杰  丁克强  李振高  刘方  骆永明  朱烨 《土壤》2015,47(4):711-718

采用温室盆栽试验,在种植紫花苜蓿的同时,分别施加木霉菌剂、根瘤菌菌剂以及木霉与根瘤菌复合菌剂,并采用离心分级法将处理后土壤分为4个粒径团聚体,即细黏粒(0.1~1μm)、粗黏粒(1~5μm)、粉粒(5~50μm)以及细砂粒(50~250μm),分析了植物–微生物联合作用对不同粒径土壤中PAHs的去除效应。研究结果表明:紫花苜蓿–根瘤菌联合作用对PAHs污染土壤的修复效果最优,其降解率达60%以上。不同粒径组分中PAHs含量的分布表现为细砂粒粉粒粗黏粒细黏粒,且PAHs在不同粒径团聚体中去除率差异性较大。低环(2、3环)PAHs在各粒径组分中去除率较低(20%以下),并在不同粒径组分间呈非均衡分配状态;4环PAHs的去除主要集中在粉粒和细砂粒中,而5环PAHs的去除主要发生在细黏粒上。可见,PAHs在土壤不同粒径组分中分布特征及降解效应为进一步阐明PAHs污染土壤的生物修复机制提供了科学依据。  相似文献   

不同填充颗粒半径水稻种子离散元模型参数标定   总被引：5，自引：0，他引：5  

张荣芳  焦伟  周纪磊  祁兵  刘虎  夏倩倩 《农业机械学报》2020,51(S1):227-235

气固两相流耦合仿真被广泛运用在气力式排种器工作过程的研究中,因确定性颗粒轨道数值计算模型的需求,种子多采用颗粒聚合的方法建模,该方法采用的填充球颗粒半径越小、数量越多就越能接近种子的真实形态,但会造成仿真计算资源过度消耗、仿真时间增长。为研究不同填充球半径的水稻种子模型对颗粒间的动力学响应特性的影响,寻找种子模型最佳的填充球颗粒数量,本文以水稻种子为研究对象,借助三维扫描与逆向拟合的方法获取种子外形轮廓,分别采用不同半径（0.30、0.21、0.18、0.16、0.15mm）的球颗粒对其进行填充,形成气固耦合的水稻颗粒粘结聚合模型。采用无底圆筒提升、滑落堆积的真实试验与仿真测定,采用曲面响应法,以休止角为指标,标定出不同填充球颗粒半径种子模型的种间静摩擦因数和动摩擦因数;通过圆筒提升和滑落堆积试验对参数进行验证,以仿真试验休止角的变异系数为指标,结果表明随着填充球半径的减小,仿真结果越接近真实值;通过水稻正压式排种器气固两相流耦合仿真进行验证,以充种率为指标,结果表明填充颗粒半径为0.21mm,仿真时长与仿真精度最优。  相似文献   

Inconel 718合金的磁性复合流体抛光工艺     

Oumar Souleymane A Kiari  姜晨  高睿  张瑞 《农业装备与车辆工程》2021,(1):27-31

针对Inconel 718合金材料加工中不断提高的表面质量需求,研究了采用磁性复合流体(Magneticcompound fluid)抛光Inconel718合金材料的加工工艺.根据磁性复合流体抛光原理搭建Inconel718合金抛光实验平台,进行不同抛光方向、抛光时间、抛光转速等工艺参数下的Inconel718合金抛...  相似文献   

不同动态水压模式下迷宫流道内颗粒物运动特性研究   总被引：4，自引：0，他引：4  

郑超  吴普特  张林  朱德兰  赵笑  安伯达 《农业机械学报》2017,48(3):294-301

采用PTV技术,观测三角函数、三角、台阶、矩形波形动态水压模式下迷宫流道内颗粒物的运动情况,分析不同动态水压模式下迷宫流道内单个颗粒物运动轨迹、运动速度及流体流场,揭示动态水压抗堵塞机理。结果表明:相对于三角、台阶及矩形波形动态水压模式,三角函数波形动态水压模式下颗粒物滞留滞止区内的时间最短,颗粒物的沉积概率最小,水流对颗粒物的输移能力最大;三角函数波形动态水压模式下流道内产生的水流波动效应不断冲击流道滞止区内存在的低速漩涡,加剧了滞止区水流紊动,进入滞止区的颗粒物随水流不断运动,并对滞留甚至沉积在滞止区内的颗粒物发生强烈冲击,使得颗粒物离底悬浮,返回主流区,并迅速通过流道,增大了水流对颗粒物的输移能力,增强了流道的抗堵塞性能。  相似文献   

Cigarette dust particles induced lung function injury of chronic obstructive pulmonary disease in mice     

JIA Min  FAN Wen-hua  QIN Qiao-hong  ZHANG Han  CHEN Yu-long 《园艺学报》2019,35(10):1915-1920

AIM: To investigate the pathogenesis of chronic obstructive disease (COPD) in mice by using nasal drip of cigarette dust particles (DSP) induced pulmonary function damage model.METHODS: BALB/c mice were randomly divided into control group, LPS 100 mg/L group, DSP 0.75 mL/L group, DSP 1.5 mL/L group and DSP 3 mL/L group for 30 days. The method of nasal drip was used for 30 days to establish the COPD model. Rrs, Ers, Crs, Est, Cst, P-3/8Rn, P-3/8G and P-3/8H were measured for evaluating lung function of the mice in each group by the method of FlexiVent. The effect on the increase of airway resistance induced by methacholine (Mach) was determined using main bronchial rings by Myograph method. The HE, Masson and Resorcinol fuchsin staining of mouse tracheas and lung tissues were conducted. RESULTS: Continuous nasal drip with DSP for 30 days increased Rrs, Ers, Est, P-3/8Rn and decreased Crs, Cst, P-3/8G and P-3/8H in the mice. DSP significantly shifted the dose-effect curve of tracheal contraction induced by Mach to the left, increased the sensitivity of the airway to Mach, and significantly increased the maximal contractile airway effect of Mach. Exposure to DSP caused fibrosis of airway subepithelial, deposition of collagen in the airway basement membrane under the reticular plate, induced reticular plate thickening, pulmonary bronchial lumen serious deformation, and the inflammatory cell infiltration in the lung of mice. Significantly increased alveolar wall muscle fibers and collagen fibers were also observed. CONCLUSION: The lung function and pathomorphological changes of COPD mice induced by 30 days nasal drip of cigarette dust particles were similar to those of human COPD.  相似文献   

油液污染颗粒引起的齿轮泵劣化失效研究   总被引：1，自引：0，他引：1  

刘勇  马彪  张赛飞  颜煜 《农业机械学报》2015,46(2):316-321,327

综合传动系统油液污染度较高,污染颗粒磨损极易引发齿轮泵流量劣化。基于齿轮泵流量劣化机理,从颗粒破碎的微观角度建立了端面间隙泄漏通道的污染颗粒破碎模型,确定了颗粒破碎常数与泄漏因子的取值。在此基础上推导齿轮泵流量劣化模型,建立了污染颗粒质量与磨损参数的线性关系,并分析了污染颗粒浓度、齿轮泵结构参数等影响因素。试验验证结果表明,齿轮泵流量劣化模型能较好地解释颗粒破碎、磨屑生成等污染磨损过程,并从理论角度提出齿轮泵污染耐受度的估算方法。该模型对于综合传动液压润滑系统设计与污染控制研究有重要的实用价值。  相似文献