Pre-harvest spraying of oxalic acid improves postharvest quality associated with increase in ascorbic acid and regulation of ethanol fermentation in kiwifruit cv. Bruno during storage

The kiwifruit trees(Actinidia deliciosa cv.Bruno)were sprayed with 5 mmol L-1 oxalic acid(OA)or water(as control)at 130,137 or 144 d after full-blossom,and then the fruit were harvested at commercial maturity and stored at room temperature(20±1)℃ for 13 d.The effect of pre-harvest spraying of OA on postharvest quality of kiwifruit was evaluated during storage.The OA spraying slowed the increase in soluble solids content(SSC)and decrease in titratable acid(TA),as well as increased contents of ascorbic acid(AsA)and total-AsA accompanied with higher AsA/DHA ratio in kiwifruit during storage.Moreover,the OA spraying significantly reduced the contents of acetaldehyde and ethanol in kiwifruit,along with significant decrease in activities of enzymes involved in ethanol fermentation metabolism during the later period of storage,which was beneficial to control off-flavor associated with over accumulation of ethanol during postharvest.It was suggested that pre-harvest spraying of OA might maintain the postharvest quality of kiwifruit in relation to delay in fruit ripening,AsA maintenance and regulation of ethanol fermentation.

Spraying Arginine at 5 Days before Harvest Delays Postharvest Broccoli Senescence via Nutrient Accumulation

To determine the effects of preharvest arginine spraying on the nutritional level of broccoli and the mechanism of action of arginine in improving the storage quality of broccoli,arginine spraying(5 mmol/L)was conducted at 0,1,3,and 5 days before harvest.The appearance,respiration rate,mass-loss rate,electrolyte leakage,glucosinolate,ascorbic acid,total phenol,total flavonoid,total sugar and sucrose contents,and sucrose phosphate synthase(SPS),invertase(INV),sucrose synthase synthesis(SSS)and cleavage(SSC)activities of broccoli samples were observed after 0,2,4,6,8,and 10 days of storage.The results showed that spraying arginine at 5 days preharvest(5-ARG)helped to inhibit broccoli respiration during storage,delay electrolyte leakage,and maintain broccoli color.Furthermore,during the growth stage,total sugar accumulation was higher in the 5-ARG group.In addition,during the storage period,sucrose synthesis was accelerated,while sucrose cleavage was inhibited,resulting in more sucrose retention in postharvest broccoli.In conclusion,5-ARG resulted in the accumulation of more nutrients during the growth process and effectively delayed the quality decline during storage,thereby prolonging the shelf life of broccoli.Therefore,this study provides a theoretical basis for improving postharvest storage characteristics of broccoli through preharvest treatments.

CsABF3-activated CsSUT1 pathway is implicated in pre-harvest water deficit inducing sucrose accumulation in citrus fruit

Pre-harvest water deficit(PHWD)plays an important role in sugar accumulation of citrus fruit.However,the mechanism is not known well.Here,it was confirmed that PHWD promoted sucrose accumulation of citrus fruit,but had limited effect on fructose,glucose and total acid.A sucrose transporter,Cs SUT1,which localizes to the plasma membrane,was demonstrated to function in sucrose transport induced by PHWD.Compared to wild-type,Cs SUT1 overexpression in citrus calli stimulated sucrose,fructose and glucose accumulation,while its silencing in juice sacs reduced sucrose accumulation.Increased sugar accumulation in transgenic lines enhanced plant drought tolerance,and resulted in decreased electrolyte leakage,malondialdehyde and hydrogen peroxide contents,as well as increased superoxide dismutase activity and proline contents.An abscisic acid(ABA)-responsive transcription factor,Cs ABF3,was found with a same expression pattern with Cs SUT1 under PHWD.Yeast one-hybrid,electrophoretic mobility shift assay and dual-luciferase assays all revealed that Cs ABF3 directly bound with the Cs SUT1 promoter by ABA responsive elements.When Cs ABF3 was overexpressed in citrus calli,the sucrose,fructose and glucose concentration increased correspondingly.Further,transgenic studies demonstrated that Cs ABF3 could affect sucrose accumulation by regulating Cs SUT1.Overall,this study revealed a regulation of Cs ABF3 promoting Cs SUT1 expression and sucrose accumulation in response to PHWD.Our results provide a detail insight into the quality formation of citrus fruit.

Development of Spraying Devices for Interplantation in Forest

Honghuagang District,Zunyi City,Guizhou Province,develops the characteristic industry of crispy peaches,and at the same time develops the forest economy and promotes the model of planting soybeans in peach orchards to promote rural revitalization.However,due to the different pests and diseases occurring in peach trees and soybeans,the control drugs used are also different,and the existing technology for spraying and controlling peach or soybean seedlings is operated separately and cannot be sprayed together at the same time.This study,based on the actual situation of forest land,develops a spraying device for interplantation in forest(peach tree and soybean)from the aspects of technical solutions,working principles and beneficial effects,in order to solve the problem of low spraying efficiency of spraying control of peach tree or soybean seedlings in the existing technology.

3WF-1300型悬挂式喷杆喷雾机的设计与试验

针对我国目前大田喷雾机仍以中小型机具为主,产品技术含量相对较低,使用可靠性差,施药过程存在雾滴飘移、喷洒不均匀、农药有效利用率低等问题,在分析悬挂式喷杆喷雾机工作原理的基础上设计并研制了一种高效、安全的3WF-1300型悬挂式喷杆喷雾机。该机配套动力为88.2~117.6 kW,药箱容量1 300 L,喷幅18 m,可液压控制喷杆折叠、展开和升降,有效降低了驾驶人员的操控难度,能够实现舒适、精准、高效的农药喷施作业,提高了农药有效利用率、降低了农药施用量、减少了环境污染,极大地保护了操控人员的身体健康。田间试验结果表明:喷雾机结构参数设计合理,喷杆的折叠、展开和升降过程平稳顺滑,无卡顿现象;喷雾均匀,作业效率高,达到了设计指标的要求;田间试验中,沿喷杆方向喷雾分布变异系数为5.3%,结果优于国家标准。

喷雾助剂对乙基多杀菌素药液在杧果叶片润湿铺展行为的影响

乙基多杀菌素是防治杧果蓟马的常用药剂之一,农药喷雾助剂的添加可以提高农药的药效。合理选择和使用助剂产品,对提高农药利用率、减少农药使用量至关重要。本研究通过测定添加5种不同类型、不同浓度的农药助剂产品后乙基多杀菌素药液的静态、动态表面张力,以及药液在杧果叶片正面、背面的接触角、铺展面积和蒸发时间,探究不同类型农药助剂产品在杧果叶片表面的润湿铺展行为。结果表明:添加不同助剂产品均能有效降低乙基多杀菌素药液的静态、动态表面张力,同时降低药液在叶片表面的接触角,提高药液在杧果叶片表面的铺展面积。除高分子类助剂(诺普信天盾)在叶片背面表现出抗蒸发性外,其他助剂产品均缩短了蒸发时间。不同类型的助剂产品在杧果叶片上的润湿性表现并不一致,有机硅类助剂(极润)润湿性最好,其余依次为硅酸金属复合盐类助剂(迈道)、改性植物油(迈飞)、橙皮精油(丹罗丰)、高分子类助剂(诺普信天盾)。通过比较不同处理组药液在杧果叶片正面、背面的润湿铺展行为,得出叶片背面比正面更难以被农药药液润湿。药液的理化性质和叶片的表面结构是影响喷雾液滴在叶片上润湿行为的重要因素。杧果蓟马常常在叶片背面活动取食,因此在防治杧果蓟马时,应根据助剂的类型、蓟马的为害特点选择合适的浓度,才能取得较好的防治效果。研究结果揭示了不同类型助剂在杧果叶片上的润湿铺展行为,为合理选择使用农药喷雾助剂产品提供数据支撑。

自走式喷杆喷雾机喷雾沉积特性试验研究

为了探究各因素对喷杆喷雾机喷雾沉积的影响规律,进一步提高自走式喷杆喷雾机的作业效率,使用Box-Behnken响应面法,分析并得到前进速度v、工作高度h和喷雾压力p等影响因素与喷雾沉积特性的数学模型,根据回归分析结果得出各影响因素对喷雾沉积特性的影响程度以及喷雾机最佳工作参数.结果表明:前进速度、工作高度和喷雾压力均对喷雾沉积特性有显著影响,影响程度按因素排序由大到小为喷雾压力,工作高度,前进速度.单位面积雾滴沉积量均值与前进速度和喷头工作高度成负相关,与喷雾压力成正相关.沉积量变异系数与喷雾压力成负相关,与前进速度成正相关,与工作高度的增加呈先减小后增大的趋势,这说明在工作高度一定的情况下,增大喷雾压力或者减小前进速度可以有效提高喷雾机的雾滴沉积均匀性.

自识别高效智能植保装置设计

传统植保喷药方式存在喷洒不均匀、用药量大、成本高等问题。针对上述问题基于单片机设计了一款智能植保装置,该装置能够实现自动避障、遥控农药喷洒、植物图像识别区分及除草植保功能。装置由STM32系列单片机、OpenMV识别模块、光电自动避障模块、NRF24L01无线通讯模块、显示模块共同组成。测试结果表明,智能植保装置性能良好,可以满足农业生产的要求。

Corrosion resistance of Fe-based amorphous metallic matrix coating fabricated by HVOF thermal spraying

The Fe-based amorphous metallic matrix coating （Fe-AMMC） was fabricated with the powder mixtures of Fe-based metallic glass synthesized with industrial raw materials, NiCr alloy and WC particle by high velocity oxy-fuel （HVOF） spraying. The corrosion resistance of Fe-AMMC was investigated by potentiodynamic polarization tests in 1 mol/L HCl, NaCl, H2SO4 and NaOH solutions, respectively. The surface morphologies corroded were observed by SEM. The results indicate that Fe-AMMC exhibits excellent corrosion resistance, higher corrosion resistance than 304L stainless steel in the chloride solutions. The low corrosion current density and passive current density of Fe-AMMC with a wide spontaneous passivation region are about 132.0μA/cm2 and 9.0 mA/cm2 in HCl solution, and about 2.5 μA/cm2 and 2.3 mA/cm2 in NaCl solution. The excellent corrosion resistance demonstrates that Fe-based amorphous metallic matrix powder is a viable engineering material in practical anti-corrosion and anti-wear coating applications.

Effects of Spraying Nitrogen and Zinc Fertilizers after Flowering on Grain Weight and Nutritional Quality of Winter Wheat

In order to explore the effect of spraying fertilizers after flowering on grain weight and nutritional quality of different winter wheat cultivars, twenty wheat culti- vars in wheat zones along Yellow River and Huai River, were used to investigate the change of thousand kernel weight （TKW）, phytic acid content （PAC）, contents of Fe, Zn and Mg and bioavailability by spraying zinc and nitrogen fertilizers after flowering. The results showed that both of TKW and protein content in grains in- creased by spraying Zn and N fertilizers, and the effect of N fertilizer proved more significant. The PAC decreased significantly after Zn treatment, for example, PAC of ＂955159＂, a wheat cultivar, decreased by 27.95%. However, PAC was in- significantly influenced by N fertilizer. On the other hand, Zn content in wheat grains were improved after spraying Zn fertilizer and the increase aveaged 54.38%. Furthermore, Fe and Zn contents grew significantly after spraying N fertilizer, and the increase averaged 36.88% and 11.25% respectively. However, Mg content in grains declined by N fertilizer. Still, the bioavailability of zinc in grains was enhanced after spraying Zn fertilizer, and of Fe was also increased greatly after spraying N fertilizer. In conclusion, grain weight, and content and effectiveness of mineral ele-ments can be improved simultaneously by rational spraying of N and Zn fertilizers to improve quality of grains.

Application of New Slope Greening Technology——Reinforced Organic-Material and Plant Seeds Spraying

The research introduced the flowchart of organic-material and plant seeds spraying and a case of ＆quot;Dasi＆quot; Highway, the highway from Daxing to Sinan in Guizhou Province, a part of a National Highway from Hangzhou to Ruili, cal ed Hangrui Highway, slope protection. The flowchart included slope cleaning, net preparation, anchor fixation, adding vegetation-growth plate, spraying organic materi-als, coverage of non-woven fabrics, and maintenance. The technique is proved much efficient in protecting and greening road sideslopes consisting of weathered rocks or hard rocks, which provides a solution for abrupt slope greening technology.

Studies on GA_3 Spraying Dosage for eui TGMS Rice Changxuan 3S in Its Hybrid Seed Production

[Objective] Changxuan 3S was thermo-sensitive genicmale sterile（TGMS）rice selected from irradiated seeds of Peiai 64S by 350 Gy^（60）Coγ-ray.The aim of the study was to confirm GA3 spraying dosage of Changxuan 3S with eui gene in its hybrid seed production.[Method] Changxuan 3S possessing eui gene and its parent Peiai 64S were chosen as materials.Comparison studies on sensitivity to GA3 in their hybrid seed production were carried out.[Result] The suitable stage for spraying GA3 in the hybrid seed production of Changxuan 3S was at 10% of panicles headed;The optimal dosage was 90 g/hm2 with 2 split sprayings,the first spraying of 45 g/hm2 at heading of 10% panicles and the second one of 45 g/hm2 on the following day.Under the condition of spraying GA3 at the rate of 90 g/hm2,the panicle neck exsertions of Changxuan 3S was ＋1.78 cm,and exserted stigma rate and seed setting rate of Changxuan 3S were 96.87% and 36.44%,being 21.46% and 16.33% more than those of Peiai 64S,respectively.The theoretical yield of ＂Changxuan 3S/9311＂ reached 2 931.90 kg/hm2,which was increased by 1 259.40 kg/hm2 comparing with ＂Peiai 64S/9311＂.[Conclusion] Compared with Peiai 64S,Changxuan 3S is more sensitive to GA3,which results in no or little using GA3 in seed production of Changxuan 3S.Moreover,Changxuan 3S showed higher yield potential than Peiai 64S.

Growth of CuI buffer layer prepared by spraying method

CuI thin films with nano-scale grains of about 35nm were deposited via spraying method with using acetonitrile as solvent. The influence of iodine doping concentration in acetonitrile solution on the structure, topographic and optical properties of CuI thin films was investigated. X-ray diffraction results showed that CuI iodine-doped films doped CuI：I2 were in γ-phase of zinc blende structure with （111） preferential plane. Scanning electron microscopy revealed that the microstructure of CuI films depended on the relative amount of doping iodine in the solution. When the iodine doping amount in acetonitrile solution was 0.025 g, the film was uniform and compact, the optical transmittance was 75.4% in the part of visible region and the energy band gap was close to 2.96 eV.

喷雾与真空冷冻干燥方法对肉苁蓉红枣复合固体饮料品质的影响

该研究以甘肃特色资源荒漠肉苁蓉和红枣为原料,分别采用喷雾干燥(spray drying,SD)、真空冷冻干燥(vacuum freeze drying,VFD)制备固体饮料,探究不同干燥方法对固体饮料的微观结构、感官状态、物理性质、吸湿性、溶解能力及抗氧化能力的影响。结果表明,VFD较SD样品孔状结构小而多;SD样品ΔE为35.37,VFD样品ΔE为46.25,色差明显;感官发现饮料品质存在差异;物理指纹图谱分析得到SD较VFD样品具有良好的可压性、均一性,SD和VFD样品相似度为9.68%;SD样品吸湿率为19.64%,VFD样品吸湿率为18.99%,SD样品吸湿加速度小,为-0.0026 g/h^(2);SD样品溶解能力较VFD好,溶解性为96.58%,溶解时间为52.38 s,湿润下沉时间为89.85 s;模拟体外消化发现,SD较VFD样品DPPH自由基清除率好,消化结束后SD与VFD样品DPPH自由基清除率分别下降了50.64%、53.03%。分析得到干燥方法影响了固体饮料的微观结构,最终使不同干燥方法所得固体饮料的感官、物理性质与抗氧化能力等品质呈现出差异。该研究为荒漠肉苁蓉与红枣的开发提供了支撑和参考。

SIMULATION OF FLUIDIZED BED WITH TOP LIQUID SPRAYING

Simulation of the drying process in a top spraying fluidized bed is conducted.A wetting coefficient describing the wetted part of the particle surface is introduced.Using experimental data and the data regression method,the modified function of the wetting coefficient is calculated.And this function is introduced to the mathematical model,which describes the heat and mass transfer process in a liquid sprayed gas fluidized bed.Through modeling,the gas humidity and temperature profiles as well as the particle temperature profile can be obtained.Compared with the experimental results,the wetting coefficient and the mathematical model are verified.

花卉大棚喷药机器人远程控制系统设计——基于互联网

针对花卉薄膜大棚传统人工施药效率低、喷洒不均匀且漂浮药物对人体健康造成伤害等问题,设计了一种可实现远程手机控制的悬挂式喷药机器人系统。首先,根据花卉的生长特点和大棚空间结构,在不改变现有大棚结构的前提下,通过增设导轨的方式引入喷药机器人,并依据花卉精准施药的基本要求,在SolidWorks中建模并优化喷药机器人的机械结构;其次,以MCU esp8266模块作为核心控制单元,对继电器、电机、电磁阀和药液泵等硬件进行控制,采用PWM方式调节继电器的导通时间,进而实现喷药机器人根据不同行进速度作业;最后,通过WiFi无线通信模块结合物联网平台设计远程控制APP端,实现喷药机器人启停和环境数据采集等功能。系统测试表明:在无遮挡和有遮挡物环境中,数据传输的成功率分别约为98%和93%,丢包率分别约为1.98%和7%,且喷药机器人在不同的速度下运行稳定。测试结果能够为喷药机器人在大棚内行走稳定性和对花卉自动施药提供技术参考。

丘陵坡地自走式喷洒装置通过性能分析与试验

针对目前丘陵坡地中缺少适用灌溉机械现状,结合茶园种植特点及丘陵坡地的地形特征,设计了一种适用于丘陵坡地的自走式喷洒装置.对喷洒装置直线行驶、纵向爬坡及横向坡行走等常见喷洒行驶工况进行力学理论分析.采用RecurDyn多体动力学软件对装置进行建模,对常见喷洒行驶工况的装置行驶状态进行仿真分析,仿真结果表明,装置具有良好的直线行驶及爬坡性能,能顺利通过最大15°横向斜坡、最大15°纵向斜坡.研制出样机并进行了真机试验,实测样机平均行驶速度1.94 km/h,具有良好的直线行驶性能,行驶偏移率2.88%;且平稳通过坡角为13°纵向坡,并在坡度范围为8°~13°的横向坡安全稳定行驶,与仿真结果相符,满足自行走喷洒装置的坡地作业要求,为后续丘陵灌溉装备的设计提供了参考.

基于CFD的玉米田间吊喷装置仿真设计与试验

为了改善玉米作物生长至中后期时中下层叶片雾滴沉积效果差,不同冠层雾滴分布不均导致植株叶片整体雾滴覆盖率低,喷施农药方式不佳造成药害和环境污染的问题,设计了一种玉米田间吊喷装置。利用数学理论几何关系结合Fluent软件确定了关键参数,即吊杆长度为1950 mm、侧下喷头距吊杆底端高度为50 mm、侧上喷头距植株顶端高度为50 mm、侧下喷头与水平方向上夹角为38.8°、侧上喷头与水平方向上夹角为43.7°。利用Design-Expert软件以吊杆侧上喷口处压强、吊杆侧下喷口处压强、机具行进速度为试验因素,以叶片平均雾滴覆盖率Y为试验指标设计三因素三水平正交试验,经方差分析后得到影响雾滴覆盖率大小因素主次顺序:行进速度>侧下压强>侧上压强。经田间试验后得到最终组合参数为机具行进速度0.8 m/s,侧上压强0.7 MPa,侧下压强0.5 MPa,雾滴覆盖率为26.54%,上、中、下层叶片雾滴覆盖率分别为28.32%、23.54%、27.75%,模型仿真与田间试验相对误差为5.05%。研究结果可为玉米植保机械的研发提供参考。

基于点云语义分割的猕猴桃冠层叶密度测量方法

提出了一种基于LiDAR的猕猴桃果园叶密度测量方法,旨在为猕猴桃果园冠层喷药提供更精确的指导。首先,使用激光雷达扫描10个密度不同的猕猴桃冠层建立点云数据集,利用RandLA-Net神经网络模型并通过6折交叉验证的方法对猕猴桃冠层的树叶、树枝和T型架点云进行语义分割;然后,计算仅包含树叶信息的冠层点云表面积,通过与人工落叶后的实测冠层叶属性(叶面积、叶片数)进行回归分析比较,得到冠层叶点云表面积与真实冠层叶属性的关系;最后,将3 m×3 m的猕猴桃冠层区域划分为400个225 cm^(2)的小网格区域,用以生成冠层叶密度图。结果表明:RandLA-Net网络模型能够有效地对猕猴桃冠层的树枝、树叶与T型架点云进行分割,模型平均总体精度OA达到92%以上,平均交并比mIoU为81.4%,冠层实测叶面积与冠层叶点云表面积的回归分析中获得了较高的相关性R=0.78,回归方程为y=1.491x+8315。对于每个猕猴桃冠层点云数据,通过Alpha-shape算法计算网格区域的冠层体积和预测网格真实叶面积的方法生成冠层叶密度图。所开发的基于点云语义分割的猕猴桃冠层叶密度测量方法,各项指标均符合预期要求,可以为果园冠层喷药提供更精准的指导。

不同受力状态下镁合金冷喷涂Al-Al_(2)O_(3)复合涂层变形及应力分析

为了更深入地研究镁合金冷喷涂Al-αAl_(2)O_(3)复合涂层在不同受力状态下的力学响应,利用ABAQUS有限元软件分别在AZ31B镁合金上构建了Al-Al_(2)O_(3)复合涂层的定点下压模型、拉伸模型和摩擦模型(其中Al_(2)O_(3)质量分数分别为0%、15%、30%、45%),且对于冷喷涂试验中出现的颗粒随机性进行相应的表征,分析了涂层在不同受力状态下的应力分布及其类型,以期获得复合涂层潜在的失效机制及在不同受力(拉伸、压缩、摩擦)状态下应力之间的联系。研究表明:3种不同受力工况下应力集中现象位于Al_(2)O_(3)颗粒的边缘或附近,且应力在靠近曲率半径最小处达到最大值,但不同的受力会导致应力的类型不同。经过摩擦后的涂层最表层的涂层残余应力为拉应力,次表层则为压应力,涂层最下层则为拉应力,且最表层的残余拉应力平均值随着Al_(2)O_(3)含量增多而增大。研究结果可为涂层设计和材料选择提供理论指导,同时也为相关应用领域提供参考依据。