农业机械化推广模式创新分析

随着农业生产规模的扩大和机械化水平的提高,人们在进行农业生产的时候,已经普遍接受并采用机械化的生产模式,文章就农业机械化发展出现的问题进行了介绍,并提出了在我国进行农业机械化的推广的具体措施。     

覆盖方式对旱地小麦花后旗叶抗氧化生理及粒重形成的影响

于2017—2018年和2018—2019年,在西北中部旱作雨养农业区以冬小麦‘康庄974’为试验材料,设秸秆带状覆盖(SM)、地膜覆盖(PM)和无覆盖对照(CK)共3个栽培处理,分析不同覆盖方式对小麦灌浆期土壤水分和温度及抗氧化能力的影响,探讨花后干物质积累量和粒重形成的关系。结果表明,随生育期推进,花后旗叶相对含水量(RWC)逐渐降低,丙二醛(MDA)含量逐渐升高,且PM较SM降、升幅度明显。与CK相比,覆盖显著提高花后旗叶抗氧化酶活性,增加渗透调节物质含量;开花时间越长,SM抗氧化酶活性升高的幅度越大,而PM主要提高花后7 d旗叶抗氧化能力。SM和PM的粒重分别较CK增加14.3%和19.1%(P<0.05)。相关分析表明,土壤水分(SW)是影响旗叶生理活性的关键因子,提高SW,有利于增加RWC(r=0.84^**),从而提高旗叶抗氧化能力,其中RWC和抗坏血酸酶(ASA)活性呈极显著正相关关系(r=0.82^**);ASA活性和脯氨酸(Pro)含量呈极显著正相关关系(r=0.94^**),和MDA含量呈极显著负相...     

石墨烯膜不同加温方式对设施高架基质草莓生长结果的影响

为探究石墨烯电热膜不同加温方式对草莓生长和结果的影响,本文以红颜草莓为试材,采用草莓顶部、基质表面和根系周边组合的7种加温方式,以电热线加温为对照,研究了不同石墨烯加温方式对设施高架基质草莓植株、叶片、果实和根系等相关性状的影响。结果表明：石墨烯膜放置草莓根系附近;石墨烯膜放置于根系附近和顶部20cm处组合;石墨烯膜放置于根系附近、基质表面和植株顶部20cm处组合在各个性状表现均优于其他处理,但石墨烯膜放置于根系附近和顶部20cm处组合;石墨烯膜放置于根系附近、基质表面和植株顶部20cm处组合耗电量相对较高,石墨烯膜放置草莓根系附近处理耗电量相对较低,可以作为石墨烯的加温方式进行推广应用。     

稀燃汽油机瞬态空燃比的滑模-神经网络控制

提出了稀燃汽油机空燃比滑模-神经网络控制方案,采用滑模变结构控制对稀燃工况的空燃比进行反馈控制,采用神经网络实现对进气量的精确预测和油膜动态特性的前馈补偿,进而实现对稀燃发动机瞬态空燃比的精确控制。采用自行开发的电控系统,在一台稀燃发动机上进行了瞬态空燃比实验。实验结果表明:节气门急速变化时空燃比超调可以控制在1个空燃比单位以内,调整时间不超过3s;转速越低,节气门变化越剧烈;空燃比超调越大,调整时间越长。     

北方农牧交错带种植业能值分析 ——以武川县为例

应用能值理论从农户生产的角度分析了武川县种植业不同作物生产能值。结果表明：该县种植业生产系统能值投入率与产出率“双低”，应增加系统投入以提高产出水平；系统环境负荷率不高，不可更新环境资源破坏严重，应提高可更新环境资源利用效率、加强水土保持工作；辅助能值投入中有机能值略高于无机能值，应按适当比例增加辅助能值投入以提高系统生态经济效益，粮食产出能值中玉米、油菜所占比重高，系统结构调整应遵循生态经济原则，压缩马铃薯面积、提高玉米、油菜等作物播种面积。     

Nonlinearity of Electronic Throttle and Its Control

This paper introduces the development of the electronic throttle control system (ETCS) , the structure and the principle of the system are also involved. After analyzing the nonlinearity problem existing in the mechanical structure of the system, a mathematical model of the ETCS is built up. Then three controllers (PID controller, Fuzzy controller, sliding mode controller) were designed and simulated in the matlab simulink. The result indicates that the PID controller has an overshoot,but the Fuzzy controller and the sliding mode controller can settle the nonlinearity problem better.     

Experimental Research on High-strength Inorganic Anchoring Material

A new type of inorganic anchoring material is developed as a substitution for anchoring adhesive to overcome some imperfections in the process of planting reinforcing steel bar.The mix proportion of the anchoring material is determined by experiments.The compressive strength,adhesive force to concrete,volume stability and anchoring force with steel bar are studied.The early strength of the anchoring inorganic material is quite high: for 1d up to 38.5MPa and 3d up to 60MPa.It is a good adhesive to concrete and the adhesive strength of 28d is about 2MPa.The anchoring material will have tiny volume expansion with the age,which is beneficial to enhancing the anchoring force.The essential component of the inorganic anchoring material is cement-based material,so some defects of the organic macromolecular material can be avoided,such as poor stability and requirement for vigorous construction conditions.Its characteristics in early strength,adhesive force to concrete and volume expansion can satisfy the requirement of the construction to the planting reinforcing steel bar and the loading force,thus it can be used as a substituting material for anchoring adhesive.     

Discussion on Second-order Analysis of Variable-Section Beam-Column

In this paper, based on the discussion of orthogonal decomposition method for the buckling mode of unsymmetrical structure, taking the variable-section beam-column as an example, a simple and direct method of the second order analysis is presented. In the new method, the conception of enlargement coefficient brought forward by Timoshenko is developed. To begin with the curvature of the variable-section beam-column, the linear equations are set up. With their solution, a group of orthogonal buckling mode can be obtained. The primary deflection can be decomposed to a group of homomorphic deflection similar to buckling mode. Then, the group of deflection is multiplied by corresponding enlargement coefficient and plus the result, finally, the second-order total deflection can be obtained.     

Optimum Planting System for Energy Saving and Healthy Demanded

It is proved that planting is effective to improve environment both indoor and outdoor resulted from the functions of plants to clean air and save energy. So the contradiction between saving energy and comfort,healthy demanded by people can be solved by planting. The planting have being emphasized and expanded during recent years,but in the planting plan,just the function of beautifying the environment is concerned and the function of ecological and saving energy are neglected. The analysis on the ooptimum system of planting is to make the planting system as an organic composition in the effectiveness structure and space layout of the city. Based on the study on equivalent relation of different effects on environment, the optimum system of planting structure will be determined in order to achieve the integrated effects of planting on environment.     

Nonlinear Finite Element Analysis of RC Deep Flexural Simply Supported Beams Using Disturbed Stress Field Model

A nonlinear finite element analysis of 4 RC deep flexural simply supported beams with the program VT2 is presented. Crack development and failure modes , longitudinal reinforcement strain distributions and load -deflection curves were compared as a result in order to evaluate the validity of the disturbed stress field model to analyse such deep simply supported beam.