大蒜根茎切割一体机设计

大蒜传统地去根、去茎,多采用手工操作,效率低,且容易伤蒜、伤手。该设计是将大蒜根、茎切割一次完成,主要由动力装置、传送装置、切割装置3部分组成。工作时由电动机带动,为多路皮带传动,分别带动载有带根、茎的大蒜输送带运动以及两个根、茎圆盘切割刀转动;为保证传动协调稳定,末端传动采用了齿轮传动;为保证切削精度,对蒜头实施了精确定位,对蒜茎采取上下皮带夹持输送的方式。该机型可以实现不同大蒜尺寸的调整,特别注重了须根的切除精度。     

低速载货汽车驱动桥的设计

本设计主要针对低速货车后驱动桥,对差速器、主减速器、驱动桥壳、半轴等零部件进行了设计与选择,重点计算选择了差速器和主减速器主要参数。对称式圆锥齿轮差速器、组合式桥壳的单级主减速器、分段式桥壳及悬浮式半轴的结构设计符合低速载货汽车对驱动桥的各项要求,对促进低速货车经济的发展具有积极作用。     

水轮式增氧机行星齿轮传动设计

通过对水轮式增氧机性能要求的分析,结合安装应用条件,对传动减速装置进行了选型设计,首先对2Z—X型行星齿轮传动原理进行分析,对主要参数进行分析计算,并进行结构设计。完成了外形尺寸小、质量轻、传动平稳、传动效率高、非标准的行星齿轮减速器的设计。     

牛羊饲料搅拌机构的设计

为提高牛羊饲料的加工质量,为牛羊饲喂车设计双螺旋饲料搅拌机构,采用2个方向相反的螺旋结构搅拌饲料。详细介绍料箱、螺旋搅龙、出料口等关键部件的设计思路,通过计算确定电动机的主要参数。搅拌机设计合理,结构简单,能耗低。     

机械设备中减速器的设计分析

减速器是各类机械设备中广泛应用的传动装置,安装在原动机和工作机之间,主要用来降低转速、增大转矩,在某些场合下也可作为增速器使用。所以,正确选择减速器类型和合理设计减速器将会直接影响机械设备的传动性能。     

温室智能通风控温机传动装置的设计

在简述温室智能控温机工作原理的基础上,分析其传动装置的总体设计思路,探讨传动装置设计过程中传动方案的确定、电动机的选择以及传动比、动力参数的计算,为设施农业高产稳产提供装备保障。     

双曲线齿轮油的特点及使用方法

1.5吨级四轮农用运输车后桥的主减速器多为双曲线螺旋齿轮传动。双曲线齿轮传动具有传动平稳、承载能力强、噪声小等特点,对润滑要求较高。 馏分型双曲线齿轮油具有氧化安定     

皮带输送机的设计计算

文章从设计计算皮带输送机已知条件入手,通过选择计算带速、带宽、运行阻力、电机功率、皮带张力等参数,介绍了皮带输送机参数的计算方法,为设计者设计皮带输送机提供了参考。     

皮带输送机的设计计算

文章从设计计算皮带输送机已知条件入手,通过选择计算带速、带宽、运行阻力、电机功率、皮带张力等参数,介绍了皮带输送机参数的计算方法,为设计者设计皮带输送机提供了参考。     

减小三环减速器振动的试验研究

对三环减速器传动机理进行了研究,根据动力分析计算结果提出了减小三环减速器振动的措施,并进行了试验研究。     

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。