基于SVR逆向模型的拖拉机导航纯追踪控制方法

针对行驶过程中轮胎侧滑量、路面性质等不确定性因素导致传统拖拉机二轮运动学模型难以准确描述拖拉机运动轨迹的问题,提出了一种基于SVR(Support vector regression)逆向模型的拖拉机导航纯追踪控制方法。采用粒度支持向量回归(Granular support vector regression,GSVR)方法建立了拖拉机前进航向的逆向模型,实时获得实际转弯曲率与运动学理论转弯曲率的函数关系,逆向模型对纯追踪导航模型输出进行,校正提高了纯追踪导航控制方法的适应性和动态性能。拖拉机导航系统的路径追踪路面试验结果表明:当行驶距离大于125 m、行驶速度为1.2 m/s时,直线追踪最大横向偏差小于0.061 4 m,较常规纯追踪模型导航方法具有更好的直线追踪性能;田间试验结果表明:该导航控制方法适用于2BFQ-6型油菜精量联合直播机自动对行作业。     

自走式果园风送喷雾机的研制

针对我国果园施药生产现状,研制一种自走式果园风送喷雾机。该机包括底盘、传动系统、液压系统和作业组件;传动系统采用分路传动,并实现各传动装置独立工作;作业组件包括雾化装置、风送装置及控制系统等;同时完成果园喷雾机底盘的抗侧翻设计。试验考核和示范应用结果表明:该机性能稳定、作业顺畅,在喷雾压力1.0MPa、风机转速1 450r/min、行驶速度1.13m/s作业条件下,树冠内部枝叶正、反面平均有61.22%、20.9%的药液附着率,树冠外部枝叶正、反面平均有77.22%、37.17%的药液附着率。     

基于电磁阀的喷嘴直接注入式农药喷洒系统

设计了一种喷嘴直接注入式农药喷洒系统。通过与传统喷雾机械比较,简述了喷嘴直接注入式喷雾系统的结构和喷雾执行单元。为了实现农药定量注入,设计一种基于电磁原理的快速响应阀,并论述其工作原理和闭环控制方式。通过试验测试了喷雾执行单元的喷雾特性和喷杆组内各喷雾单元的一致性。结果表明在一定喷洒速率范围内,喷雾执行单元的喷水量和水压强存在多项式关系,农药注入量和PWM信号的高电平时间存在指数关系,其决定系数均高于0.9,并且同一喷杆组内6个喷雾单元的喷雾效果大体一致。     

基于LVDS传输线延时检测技术的土壤含水率传感器

为实现土壤含水率的快速准确监测,设计了一种基于LVDS差分传输线延时检测技术的土壤含水率传感器。该传感器将高频振荡信号分路为两通道LVDS差分信号,一个通道用于测试土壤含水率,另一个通道用于提供参考信号。由于土壤中水分的变化改变土壤介电常数,从而导致测试通道LVDS差分总线上信号传输延时的变化,则传感器检测该通道信号的传输延时就可以确定土壤含水率。为了获得LVDS总线设计线宽和线间距的最优值,以LVDS总线阻抗值均方误差最小化为目标,构建了线宽和线间距的最优化计算模型,并通过遗传算法求解出了最优线宽为0.178 9 mm和最优线间距为0.223 8 mm。试验表明,根据该参数设计的传感器在50 MHz频率时,对体积含水率8.31%以上的砖红壤土和黄壤土的预测模型为线性模型,决定系数R2为0.964 2,绝对预测误差在2.45%以内。     

Lysozyme-glucose stearic acid monoester conjugate formed through the Maillard reaction as an antibacterial emulsifier

Lysozyme-glucose stearic acid monoester (HEL-GE) conjugate was prepared through the Maillard reaction as an antibacterial emulsifier. The molar ratio of GE to HEL was 1:1. The isoelectric point was 6-7, which is lower than that of native HEL. Spectroscopic studies indicated that the alpha-helix content was slightly lower but the conformation around Trp had not changed and that the surface of the conjugate was covered with the GE moiety. The conjugate maintained approximately 53-57% of the enzymatic activity of native HEL at 40-60 degrees C and exhibited considerable resistance to proteolysis. The denaturation temperature of the conjugate was approximately 74 degrees C, somewhat higher than that of control HEL, whereas the enthalpy was about one-third of that of control HEL. The emulsifying activity of the conjugate and the emulsion stability were much enhanced compared to those of native HEL, and the conjugate maintained approximately 70% of the bactericidal activity.     

黄花梨果实冷藏适温的研究

黄花梨果实在０℃、４℃、８℃下进行贮藏试验，试验结果表明：低温可以抑制果实的呼吸作用，延缓呼吸高峰的出现，减少果实营养物质的消耗和色素的降解，延缓果实的成熟衰老；黄花梨果实的冷藏适温是４℃，在本试验条件下可贮藏６０ｄ，基本上保持原果的风味、颜色和品质，好果率仍保持１００％，失重率１．５０％；冷藏出库后采取逐渐升温或加抗氧化剂处理，在常温下７ｄ内可有效地延长果实货架寿命，尤以加抗氧化剂处理效果显著；无包装的黄花梨果实随着贮藏温度的升高，贮藏时间的延长，果实的失重率增加；而用聚乙烯薄膜袋包装则能显著地减少水分损失     

水分类型对土壤排放的温室气体组成和综合温室效应的影响

实验室研究表明,土壤排放出的温室气体（ＣＯ２、ＣＨ４和Ｎ２Ｏ）组成及总理显著地受土壤水分类型和施用秸秆的影响。连续淹水条件下,土壤仅排放微理的Ｎ２Ｏ,但排放出大量的Ｃ睡Ｃ敢条件下,土壤不排放Ｃ上键合的但排放出大量的Ｎ２Ｏ;虽然淹水的土壤排水促进Ｎ２Ｏ排放,但显著抑制ＣＨ４的排放,淹水好气交替处理的土壤其排放的ＣＯ２、ＣＨ４和Ｎ２Ｏ均在好气和连续淹水之间。根据各种温室产生温室效应的相对潜力,计算土壤     

Impact of 1-methylcyclopropene and methyl jasmonate on apple volatile production.

Climacteric Fuji apples were treated with 10 microL x L(-1) MCP (1-methylcyclopropene), 2 mmol x L(-1) MJ (methyl jasmonate), or a combination of 10 microL x L(-1) MCP and 2 mmol x L(-1) MJ. Fruit were kept at 20 degrees C for 15 days after treatment. Production of ethylene and other volatile compounds was measured prior to and 3, 7, 11, and 15 days after treatment. Ethylene production decreased 3 days following MJ treatment and then increased. MCP treatment alone or in combination with MJ inhibited ethylene production. MJ and MCP inhibited production of many volatile alcohols and esters. The production of individual alcohols and esters appears to be differentially inhibited by MJ or MCP. MJ and MCP inhibited not only production of alcohols but also formation of esters from alcohols.     

Development of apple superficial scald, soft scald, core flush, and greasiness is reduced by MCP.

1-Methylcyclopropene (MCP) was used to evaluate the role of ethylene in development of apple (Malus x domestica Borkh.) physiological disorders during storage. Granny Smith, Red Chief Delicious, and Fuji apple fruit were treated with MCP at a concentration of 1 microL L(-)(1) for 12 h at 20 degrees C. For all varieties stored at 0 degrees C, ethylene production and respiration rates were reduced for several months following MCP treatment, and firmness and titratable acidity of treated fruit were higher compared to controls. Apples treated with MCP did not develop superficial scald or peel greasiness through 6 months storage plus ripening at 20 degrees C for 7 days. Core flush was not observed in MCP-treated fruit until 6 months after treatment when the incidence was still lower compared to control fruit. MCP delayed the rise in production of alpha-farnesene and reduced accumulation of its oxidation products.     

Determination of chlorate and chlorite and mutagenicity of seafood treated with aqueous chlorine dioxide.

The use of chlorine dioxide (ClO(2)) as a potential substitute for aqueous chlorine to improve the quality of seafood products has not been approved by regulatory agencies due to health concerns related to the production of chlorite (ClO(2)(-)) and chlorate (ClO(3)(-)) as well as possible mutagenic/carcinogenic reaction products. Cubes of Atlantic salmon (Salmo salar) and red grouper (Epinephelus morio) were treated with 20 or 200 ppm aqueous chlorine or ClO(2) solutions for 5 min, and extracts of the treated fish cubes and test solutions were checked for mutagenicity using the Ames Salmonella/microsome assay. No mutagenic activity was detected in the treated fish samples or test solutions with ClO(2). Only the sample treated with 200 ppm chlorine showed weak mutagenic activity toward S. typhimurium TA 100. No chlorite residue was detected in sea scallops, mahi-mahi, or shrimp treated with ClO(2) at 3.9-34.9 ppm. However, low levels of chlorate residues were detected in some of the treated samples. In most cases, the increase in chlorate in treated seafood was time- and dose-related.