基于稳定切削点在线识别的切削颤振自动控制方法

通过试验研究了切削颤振自动控制的稳定切削点在线识别方法。结果表明,连续改变机床主轴转速时振动响应的最低点即为不发生颤振的稳定切削点。不同刀具几何形状下,发削点也可以由这种方法来准确识别。稳定切削点识别出以后,迅速调整主轴转速,以稳定切削点所对应的主轴转速进行切削,切削颤振就会得到有效控制。极限切深试验表明,以稳定切削点所对应的主轴转速进行切削可以提高机床的切削效率。     

基于神经网络专家系统的柴油机故障诊断系统

柴油机在农业机械中被广泛应用,由于运行状况复杂,故障类型和部位种类繁多.为此,提出了将神经网络技术与专家系统融合的集成式故障诊断专家系统,对柴油机进行不解体故障诊断.以燃油系统故障为例,介绍了神经网络专家系统特点、结构及诊断方法,并对295D柴油机在不同的工况下采集气缸盖的振动信号进行测试,用RBF神经网络对测试数据进行训练.训练测试结果表明,用此系统诊断295D柴油机常出现故障有良好的效果.     

基于HMM的机床切削颤振趋势预报软件的开发研究

为了准确地预报机床切削颤振趋势，在机床切削颤振趋势预报的理论和方法的基础上，开发了基于隐Markov的机床切削颤振趋势预报软件。介绍了软件系统的开发环境、应用工具以及采用VC^＋＋与Matlab语言混合编程的接口实现方法，阐述了整个软件系统的组成和基本功能。实际应用证明，该软件具有一定的理论价值和较强的实用性。     

基于机器视觉的槟榔分级方法研究

针对槟榔人工分级劳动生产率低、准确率低的问题,开展基于遗传神经网络的机器视觉槟榔分级研究。以4种类别的槟榔图像为研究对象,首先设计一个6层结构的遗传神经网络对槟榔进行分级,虽然分级准确率较高但是网络结构复杂。然后对运用主成分分析法降低图像特征的维数并将遗传神经网络简化为3层结构的方法进行研究。最后用400幅和100幅槟榔图像对这个3层神经网络进行训练和验证,经过调整网络的学习率等参数,训练和验证的准确率达到95%以上。通过神经网络模型测试试验,槟榔正确分级的准确率为90%。数据降维后的三层遗传神经网络能够实现对槟榔的实时分级,为机器分级提供了技术支持。     

基于迁移学习和改进残差神经网络的黄瓜叶部病害识别方法

针对在黄瓜叶部病害识别过程中使用传统卷积神经网络存在模型训练时间长、识别准确率低等问题,提出一种迁移学习和改进残差神经网络相结合的方法对黄瓜叶部病害进行识别。首先对数据集图像进行预处理,将数据集划分为训练集和测试集;然后对传统残差神经网络进行改进;最后使用迁移学习的方式对网络模型进行训练。利用该研究方法对不同的黄瓜叶部病害进行识别试验,结果表明该方法具有较高的识别准确率,可为其他作物的识别方法研究提供参考。      

预报机床切削颤振的新方法

提出利用机床主轴前后两转切削振动轨迹的相位差ψ来预报切削颤振的新方法，并且提出了利用等工件转角间隔采样，通过计算工件前后两转切削振动信号的互功率谱密度函数，精确确定相位差ψ的算法。理论分析和试验结果表明本文提出的颤振预报方法准确可靠，可望在实际中推广应用。     

采摘机器人自主采摘学习能力研究 —基于LM-BP神经网络

为了让采摘机器人更加快速和准确地识别目标水果的成熟度,提出了一种基于BP神经网络的自主学习方法。由于BP神经网络容易陷入局部最优值且训练效率较低,因此进行了改进,实现了LM-BP神经网络算法。测试结果表明:与BP神经网络算法相比,LM-BP神经网络算法训练学习速度更快,测试精度更高,能够满足采摘机器人对目标水果成熟度识别精度的要求,具有一定的应用价值。     

小直径钻削的稳态分析

为了反映小深孔钻削机床加工过程中枪钻的振动情况,对不同转速下的工件进行研究。基于速度型切削颤振理论、强迫再生颤振理论建立枪钻加工小深孔的动力学模型,从而得到枪钻系统的动力学方程。用MATLAB软件对动力学方程进行求解,得到在不同转速X,Y方向的振动偏移。将其结果运用到实践当中,取得了极好的加工效果。     

基于EMD与神经网络的内燃机气门间隙故障诊断

利用LabVIEW构建了基于EMD与神经网络的内燃机气门间隙故障诊断系统。用490BPG型发动机在转速为1200r/min、无负荷时进行了试验研究,采用经验模式分解EMD方法对气门振动信号进行分解,对分解得到的前4个固有模态函数IMF分别求其关联维数,将IMF1-IMF4的关联维数作为神经网络的输入向量,用4种工况的80组样本训练了内燃机气门故障诊断系统的网络模型。试验结果表明,20组测试样本的测试结果均与实际状况相一致,诊断准确率为100%,该系统能快速准确地识别内燃机气门间隙故障。     

基于RBF神经网络的拖拉机齿轮箱故障诊断

拖拉机作为一种动力机械被广泛应用于工农业生产,拖拉机结构比较复杂,故障种类繁多,本文针对拖拉机齿轮箱故障问题提出了一种基于径向基神经网络诊断方法。在MATLAB中,调用RBF软件包,选取网络设计函数为newrbe,网络输入变量为15维,将齿轮故障分为无故障、齿根裂纹、断齿三种模式,并作为网络的输出。利用训练样本集,对网络进行训练,用测试样本集对网络进测试,通过测试结果分析表明故障诊断无误,这说明了RBF神经网络对齿轮箱故障诊断的有效性。     

Overland water and salt flows in a set of rice paddies

Cultivation of paddy rice in semiarid areas of the world faces problems related to water scarcity. This paper aims at characterizing water use in a set of paddies located in the central Ebro basin of Spain using experimentation and computer simulation. A commercial field with six interconnected paddies, with a total area of 5.31 ha, was instrumented to measure discharge and water quality at the inflow and at the runoff outlet. The soil was classified as a Typic Calcixerept, and was characterized by a mild salinity (2.5 dS m⁻¹) and an infiltration rate of 5.8 mm day⁻¹. The evolution of flow depth at all paddies was recorded. Data from the 2002 rice-growing season was elaborated using a mass balance approach to estimate the infiltration rate and the evolution of discharge between paddies. Seasonal crop evapotranspiration, estimated with the surface renewal method, was 731 mm (5.1 mm day⁻¹), very similar to that of other summer cereals grown in the area, like corn. The irrigation input was 1874 mm, deep percolation was 830 mm and surface runoff was 372 mm. Irrigation efficiency was estimated as 41%. The quality of surface runoff water was slightly degraded due to evapoconcentration and to the contact with the soil. During the period 2001–2003, the electrical conductivity of surface runoff water was 54% higher than that of irrigation water. However, the runoff water was suitable for irrigation. A mechanistic mass balance model of inter-paddy water flow permitted to conclude that improvements in irrigation efficiency cannot be easily obtained in the experimental conditions. Since deep percolation losses more than double surface runoff losses, a reduction in irrigation discharge would not have much room for efficiency improvement. Simulations also showed that rice irrigation performance was not negatively affected by the fluctuating inflow hydrograph. These hydrographs are typical of turnouts located at the tail end of tertiary irrigation ditches. In fact, these are the sites where rice has been historically cultivated in the study area, since local soils are often saline-sodic and can only grow paddy rice taking advantage of the low salinity of the irrigation water. The low infiltration rate characteristic of these saline-sodic soils (an experimental value of 3.2 mm day⁻¹ was obtained) combined with a reduced irrigation discharge resulted in a simulated irrigation efficiency of 60%. Paddy rice irrigation efficiency can attain reasonable values in the local saline-sodic soils, where the infiltration rate is clearly smaller than the average daily rice evapotranspiration.     

瓦房店市水果生产标准化发展研究

瓦房店市是我国重要的水果生产基地,在国内水果生产领域占有重要地位。随着水果市场化的不断深入,如何满足和适应国内外市场需求成为瓦房店市水果生产的关键问题。从瓦房店市水果生产实际出发,阐述了实施水果生产标准化的必要性,提出了发展水果生产标准化的具体措施。     

金谷子耐旱TG118引种试种及推广应用

对引进的谷子新品种金谷子耐旱TG118进行品种比较试验和多点试种。结果表明：该品种抗旱、耐瘠、适应性强,稳产、高产、抗病抗风抗倒伏强,品质优良,粮草兼用,种植简单,省工易管;一般产量在6000kg/hm2以上,比当地主栽品种增产20%以上。最高产量达9450kg/hm2,适于在辽西北地区推广应用。     

对《种子法》存在问题的探讨

《种子法》是我国种植业第一部法律。自实施以来,为依法加强种子管理提供了有力的法律支撑,促进我国种子产业发生翻天覆地的变化。但随着依法管理工作的深入和种子产业的快速发展,《种子法》及配套规章的一些问题逐步显现出来。对《种子法》及配套规章存在的问题进行深入分析,对需要进一步补充的章节以及需要调整的内容进行深入探讨,以求更加完善和明确。     

Review of the Egyptian experience in implementing land drainage projects

About 30 years have passed since the Government of Egypt embarked on implementing a series of large scale drainage projects. At present, about 3.8 million acres have been provided with drainage systems on the basis of systematic pre-drainage investigations and designs. The target is to provide drains in approximately 6.4 million acres in the Nile Valley and Delta.The implementation of the subsurface drainage system is carried out by the public sector and private contractors under direct supervision of governmental regional departments. The implementation process depends on many factors related to the drainage material, machinery, manpower, site requirements, farmers and organizations involved. Problems and constraints are sometimes challenging, however, the annual rate of implementation has gradually increased to 170,000 acre/year.This paper discusses the different aspects involved in the implementation process of drainage systems. The development in materials, machinery and construction technologies will be reviewed. Institutional and management factors are going to be also considered.     

和谐社会理论建设的几点哲学思考

在新世纪,面对机遇和挑战,党的十六大把“社会更加和谐”作为全面建设更高水平的小康社会的一个重要目标。中国人素有社会和谐的理想;西方人自古也向往社会和谐;借鉴东西方两种和谐社会思想的经验、教训,构建社会主义和谐社会理论。     

A European irrigation map for spatially distributed agricultural modelling

We present a pan-European irrigation map based on regional European statistics, a European land use map and a global irrigation map. The map provides spatial information on the distribution of irrigated areas per crop type which allows determining irrigated areas at the level of spatial modelling units. The map is a requirement for a European scale assessment of the impacts of irrigated agriculture on water resources based on spatially distributed modelling of crop growth and water balance. The irrigation map was compiled in a two step procedure. First, irrigated areas were distributed to potentially irrigated crops at a regional level (European statistical regions NUTS3), combining Farm Structure Survey (FSS) data on irrigated area, crop-specific irrigated area for crops whenever available, and total crop area. Second, crop-specific irrigated area was distributed within each statistical region based on the crop distribution given in our land use map. A global map of irrigated areas with a 5′ resolution was used to further constrain the distribution within each NUTS3 based on the density of irrigated areas. The constrained distribution of irrigated areas as taken from statistics to a high resolution dataset enables us to estimate irrigated areas for various spatial entities, including administrative, natural and artificial units, providing a reasonable input scenario for large-scale distributed modelling applications. The dataset bridges a gap between global datasets and detailed regional data on the distribution of irrigated areas and provides information for various assessments and modelling applications.     

粉质仪和拉伸仪在面粉生产中的应用

在介绍粉质仪和拉伸仪结构和原理的基础上,探讨了粉质曲线中吸水率、形成时间、稳定时间、弱化度和评价值等指标与面粉品质的关系,以及如何根据拉伸曲线中面团最大拉伸阻力、延伸度和拉伸曲线面积等指标来评价面团品质,并结合生产实际,概述了粉质仪和拉伸仪在面粉生产中的作用。     

农村信息化服务的现状及建设措施

分析当前我国农村信息化服务的现状,提出加强农村信息化服务的新举措。     

车辆ABS控制算法的研究及探讨

对现代汽车的ABS控制算法作了一些简单的介绍,同时指出了它们的一些缺陷,相应地提出了几种对ABS的其它控制方法并加以探讨,其中着重论述了ABS门限值控制算法中参考车速的确定方法和基于附着系数的控制算法。