可重构机床模块划分研究

综合考虑重构需求、结构功能和生命周期的影响,使用柔性模块划分方法对可重构机床模块划分进行了研究。采用层次分析法对影响模块形成的因素进行了权重分配,得到了机床零件之间的交互值并形成了相关矩阵,使用模糊聚类法对相关矩阵进行操作;考虑到可重构机床的特殊性,对其控制系统也进行了模块划分,最后得到了可重构机床模块划分的总体方案。     

可重构机床模块划分研究

综合考虑重构需求、结构功能和生命周期的影响,使用柔性模块划分方法对可重构机床模块划分进行了研究.采用层次分析法对影响模块形成的因素进行了权重分配,得到了机床零件之间的交互值并形成了相关矩阵,使用模糊聚类法对相关矩阵进行操作;考虑到可重构机床的特殊性,对其控制系统也进行了模块划分,最后得到了可重构机床模块划分的总体方案.     

集成复杂网络和可拓聚类的复杂产品系统模块划分方法

模块生产理念和方式如今已成为农机企业的高度需求。针对复杂产品系统模块划分方法进行研究,基于梯形直觉模糊数理论对加权复杂网络的边权进行了定量分析。构建了产品的结构、功能及客户参与度3个维度的相关性矩阵,并确定综合相关矩阵。对关联矩阵利用可拓聚类进行处理,选取阈值得到了模块划分方案。以玉米收割机为例,验证了方法的实用性与有效性。      

基于UG的组合机床模块化设计

根据模块化设计原理,在功能分析的基础上划分组合机床的各级模块。以三维设计软件UG为开发平台,建立了组合机床各级模块的参数化三维造型模板库,同时还建立了存放设计过程中所需数据的数据库。用户在系统的引导下可完成设计过程中的模块选择、模块组合和设计计算等环节,从而实现了计算机辅助组合机床模块化设计,提高了设计效率。     

考虑零部件间间接连接关系的模块划分方法

模块化的产品架构可以缩短研发周期、提高研发效率和产品可靠性,有效解决大规模生产和多样化客户需求之间的矛盾。针对现有模块划分方法常忽略零部件间间接连接关系对模块划分的影响,造成重要设计依赖信息遗失的问题,建立了基于电容类比法的节点相似度模型,量化了零部件间直接和间接连接关系共同作用的效果,实现了模块的精确划分。首先,采用区间直觉模糊集分析了零部件之间的综合关联关系,将综合关联自相关矩阵映射为复杂网络;然后,建立了基于电容类比法的节点相似度模型,并以该相似度模型为中心度测度,提出了一种网络层次聚类(Network hierarchical clustering,NHC)算法,实现了复杂农机装备的模块精确划分;最后,对联合收获机脱粒装置进行模块划分,验证了NHC算法的有效性。采用NHC算法获得的划分方案的平均模块度比改进的GN算法提高了24.6%,获得的产品结构树比改进的GN算法更合理。     

面向零件群加工的可重构制造工艺设计方法

将可重构制造工艺方案设计与可重构机床结构特点相结合,以所建立的工序单元、工序段概念为出发点,通过对零件族加工信息的程式化处理,建立了加工信息矩阵,给出了工序单元创建方法和工序段方案的划分方法,通过交叉双向组配方式获得了多种满足加工要求的工艺方案;以所建立的工艺方案相似性判定模型为基础,找出可供可重构机床结构重构的合理工艺方案,为实现零件群内部加工柔性化提供了科学依据。最后以发动机缸盖零件群加工工艺设计为例,验证了方法的有效性。     

面向设计的产品模块划分方

提出了面向产品设计的模块划分方法.首先对产品子结构间的功能和结构相关性进行了分析,应用模糊树图聚类算法,探讨了模块的聚类形成过程,得到多种模块划分方案.然后,基于信息熵理论,以模块化产品设计中的横系列设计复杂度、纵系列设计复杂度和更新换代设计复杂度为优化目标,建立了面向设计的模块划分方案数学评价模型,对模糊树图法聚类得到的多个方案进行评价,从而得到最合理的模块划分方案.最后,以石材花线制品加工设备为例,验证了该方法的有效性和合理性.     

基于F-B-S模型的SAM产品可重构模块设计

提出了一种小型农业作业机(SAM)产品可重构模块开发的新方法,将公理化设计技术(AD)应用于产品模块设计过程中,针对模块功能分解进行了F-B-S模型的构建和分析,以SAM产品核心模块变速箱为实例,进行了公理化设计和可重构模块的F-B-S模型验证。结果证明上述设计方法在SAM可重构模块开发中能实现模块的快速设计和重组,为产品的快速设计和建立SAM产品可重构模块资源提供了一种开发方法。     

数控成形磨齿机计算机辅助模块化设计

将CAD技术与模块化技术相结合,开发了数控成形磨齿机模块化CAD系统.根据模块化设计原理,在功能分析的基础上划分机床的各级模块.以三维设计软件UG为开发平台,建立机床各级模块的参数化三维造型模板库,同时还建立了存放设计数据的数据库.用户在系统界面的引导下可完成设计过程中的模块选择、模块组合和设计计算等环节,从而实现数控成形磨齿机计算机辅助模块化设计.     

一种可重构轮式机器人的对接机构设计

为了让机器人具有良好的环境适应性,本研究设计了一种可重构的轮式机器人系统,系统中的每个单元模块都可以作为独立个体进行作业或与其他单元模块重构连接进行协同工作;单个模块主要由对接箱体、三轮全向轮底盘等组成,模块间通过对接箱体侧面设计的对接机构组合连接;使用SolidWorks和ADAMS对单模块机器人进行三维建模以及对接机构的运动仿真。仿真结果表明,电推杆的位移量约为7.7 mm,小于所选择的电推杆的最大位移量10 mm,验证了对接机构设计的合理性,为进一步实现多模块机器人的自重构打下基础。     

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。