基于数据采集卡的转速测量方法及实现

为了研究柴油机相继增压系统的性能，实现相继增压柴油机涡轮增压器超速保护，需要实时测量多个涡轮增压器的转速以及柴油机的转速。本文给出了一种基于微机和数据采集卡测量涡轮增压器转速、内燃机转速的方法及其算法实现。该速度测量方法的测速精度、测速个数能够满足相继增压柴油机速度测量要求。     

车用柴油机涡轮增压器的匹配比较

采用国产和进口两种增压器,通过进行柴油机台架试验,测量了不同转速时,柴油机的功率、扭矩、中冷温度、中冷压力、燃油消耗率等性能参数,得到高、中、低转速时,进口增压器和国产增压器相关性能指标的比较结果。     

基于微机并口中断方式的转速测量系统设计

设计了一种水力测功机转速微机测量系统，该系统使用微型PC机并口中断方式计数测最外部转速信号，为发动机转速及功率测试试验提供了一种新的方法及手段。     

动态转速测量的方法

动态转速测量在内燃机试验研究中有着广泛的应用,如转速波动、调速率、起动过程、增压器转速的过渡过程、调速器速敏元件的动态特性等都要测量动态转速。本文简要介绍测量仪器及影响测量精度的主要因素。 为满足柴油机及其零部件试验对动态转速测量的要求,以及保证一定的测量精度,测量装置应满足以下要求:①转速范围。柴油机性     

废气涡轮增压器润滑条件的改进技术

废气涡轮增压器作为一种能够大幅度提升发动机功率质量比的装置,在发动机上获得了广泛应用。虽然该装置的结构较为简单,但在使用过程中,由于转速较高,所以对润滑提出了较高的要求,若是润滑不够充分,则会导致轴承损坏,从而缩短增压器的使用寿命。鉴于此,本文首先对废气涡轮增压器进行概括性介绍,在此基础上提出废气涡轮增压器润滑条件的改进技术,期望通过本文的研究能够对延长废气涡轮增压器的使用寿命有所帮助。     

增压中冷柴油机与增压器匹配试验分析

对1台6缸、直列、水冷、增压中冷、四冲程车用直喷式柴油机与两种带放气阀的增压器进行匹配试验,测量分析了柴油机经济性、动力性、排放及空燃比、进排气压力、温度等。增压器放气阀较早打开,其低速供气较好,高速供气较差,柴油机中低转速经济性较好,低速时动力性较好,高速时动力性及经济性基本不变,可满足车用柴油机的匹配要求。     

基于LabVIEW振动信号分析测量电机转速

以某大型电机为典型研究对象,比较了传统的电机转速测量方法的优劣。以LabVIEW作为软件开发平台,监测电机运行时的振动信号,对得到的信号进行频谱分析、低通滤波等。从实测振动信号中计算出电机转速,达到了由振动信号分析实现电机转速测量的目的。     

涡轮增压器的合理使用与维护

常见涡轮增压器的合理使用与维护方法如下: 柴油机启动后,涡轮增压器即开始运转.务必先低速运行3～5min,待机油温度上升、流动性能好转,涡轮增压器得到充分润滑后,再提高转速并带负荷作业,以确保在高转速下增压器涡轮转子轴及轴承的润滑,避免柴油机负荷加大时,增压器转子轴及轴承出现无油干摩擦或烧卡现象.     

谈谈柴油机几种故障的预防

1废气涡轮增压器故障的预防废气涡轮增压器利用发动机排气的压力波推动涡轮旋转,带动涡轮另一端的叶轮压气机,使叶轮以非常高的转速旋转,强制将空气压入气缸,以增加空气的充     

PM4025型柴油机转速表

为配合慈溪动力机总厂Z190F、285F／290F型柴油机的配套工作而研制的PM4025型柴油机转速表于1994年6月在浙江省慈溪市问世。这种转速表针对带飞轮发电机的小型柴油机工作特点，采用一种不同于传统的及目前流行的转速测量方法，利用柴油机工作时飞轮发电机发出的交流电频率严格与柴油机转速成正比的原理，把交流电频率信号送人频率表即测出柴油机相应的工作转速。基于这种原理设计了一种用于隔离充电干扰信号及自带稳压电源的专用变换器及相应的专用转速显示仪来测量柴油机转速。由于采用发电机作为传感器及转速表工作电源，因此与常规磁…     

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.     

农村剩余劳动力就业问题的探讨

论述了我国农村剩余劳动力就业的意义，并针对我国农村剩余劳动力的现状，提出多渠道促进农村剩余劳动力就业的途径和办法。     

车用发动机润滑油失效规律与更换周期研究

研究在正常使用条件下１０Ｗ／３０－ＱＣ级润滑油用于某型车用发动机时所表现的失效规律,确认期服从两参数Ｗｅｉｂｕｌｌ分布,并给出分布的尺度参数η和形状参数ｍ之最佳线性无偏估计（ＢＬＵＥ）同时,还为定量分析,计算车用发动机润滑油的使用可靠性和合理确定其更换周期提供了一套可供借鉴的方法,并给出了具体的计算实例。     

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。     

乡（镇）农业技术推广体系存在的问题及对策

乡（镇）农技推广体系是农业发展的关键。介绍朝阳市农业技术推广体系的现状,针对目前体制及运行机制、服务手段等方面存在的问题,提出适合朝阳市乡（镇）农技推广体系改革与发展的对策,以期对全省农技推广体系改革和发展起到一些借鉴作用。     

草莓的采收与贮藏

草莓果味酸甜爽口,营养价值高,为人们所喜爱的应市鲜果之一。由于草莓易受损伤和微生物侵染,因此其采收、贮藏过程极为重要。介绍草莓采收过程中的注意事项以及11种贮藏保鲜技术的实施步骤和操作方法,推介9种加工方式,为草莓产业化提供技术支持。     

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。     

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.