某LNG/柴油双燃料发动机排放性测试应用研究

为了减少汽车尾气排放造成的大气污染,以某柴油发动机为母机开发LNG/柴油双燃料发动机,搭建发动机试验台架,对改装后发动机进行排放性测试,利用最小二乘法对试验结果分析得出,改装后发动机各项排放指标均优于原柴油发动机,为今后双燃料发动机在商用汽车上的应用提供一定的参考.     

起动电动机常见故障分析

起动电动机作为发动机的起动装置,广泛应用于拖拉机、联合收割机、汽车等机动车上。现就起动电动机的常见故障分析如下,仅供参考。     

起动电动机的常见故障及原因分析

起动电动机作为发动机的起动装置广泛应用于拖拉机、联合收割机、汽车等机动车上。现就起动电动机的常见故障及其产生原因加以分析,仅供参考。     

陶瓷涡流室柴油机低温起动性的试验研究

将柴油机的金属型涡流室镶块改成氮化硅陶瓷型涡流室镶块,并在同机上进行了对比试验.试验结果表明陶瓷涡流室柴油机改善了冷机的起动性,提高了发动机的起动性能.     

陶瓷涡流室柴油机低温起动机的试验研究

将柴油机的金属型涡流室镶块改成氮化硅陶瓷型涡流室镶块，并在同机上进行了对比试验，试验结果表明陶瓷涡流室柴油机改善了冷机的起动性，提高了发动机的起动性能。     

轻油基燃料蒸发性及其对火花点火发动机性能影响研究

轻油基燃料蒸发性与普通车用汽油相比差别较大，必然影响火花点火发动机及汽车的性能。作者通过理论分析和试验研究证实：轻油基燃料蒸发性好，可显著改善发动机低温起动、预热和加速性；在正常环境条件下，燃用2号轻油基燃料的发动机及车辆不发生气阻；1、3号轻油基燃料由于蒸气压较高，在夏季使用时采用电动燃油泵或性能良好的机械式燃油泵，可消除气阻。     

突破传统局限 创新低碳未来 锡柴首创天然气机多点喷射燃气系统技术

正近期,由一汽解放汽车有限公司无锡柴油机厂(以下简称锡柴)与一汽技术中心联合自主研发成功的国内首创天然气发动机多点喷射燃气系统,已顺利完成多轮功能和机械耐久等试验,并成功搭载在锡柴天然气发动机上。该系统为国内在天然气发动机首次应用,它不仅打破了国外对其系统的垄断局势,更在提升     

起动电动机的使用与维护

起动电动机在拖拉机、联合收割机、汽车等机车上广泛应用作为发动机的起动装置。电力起动有操纵灵活、起动迅速可靠等优点,但往往由于机手对起动电动机的使用维护知识缺乏全面了解,从而造成起动电动机过早报废。为便于机手掌握起动电动机的正确使用与维护,延长其使用寿命,现分述如下: 一、使用注意事项 起动机连续工作时间不应超过30秒;再次起动时应停歇2分钟以上;三次起动不成功应检查故障的原因,排除后方可起动。发动机起动     

添加剂对压燃式天然气发动机起动性能的影响

在压燃式天然气发动机上采用二叔丁基过氧化物(DTBP)添加剂进行改善发动机起动性能的试验研究.结果表明,加入一定的DTBP可使压燃式天然气发动机起动性能得到较大的改善.在起动工况下,当添加的DTBP质量分数达到14.2%(J喷射模式)时,仅需750℃的电热塞温度就能实现常温起动;当电热塞温度高于1120℃时,常温起动的DTBP质量分数可减少到6.7%以下;过量的添加剂会导致发动机工作敲缸.     

天然气汽车的未来

■大趋势提起天然气汽车,人们不禁联想起上世纪50年代末的情景。那时,我国不少解放牌卡车的驾驶室上架着方木板,板上放一个鼓鼓囊囊的大气包。这些背着气包的汽车代表着原始的燃气汽车,或者说是第一代燃气汽车。如果说上世纪50年代用燃气代替燃油是被动的     

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。