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新疆新型高效节能日光温室标准化设计探讨 总被引:4,自引:0,他引:4
日光温室标准化设计的目的是为了提高新疆南北疆日光温室的综合性能,根据新疆的自然条件和气候特征,对两地区的日光温室建造参数进行标准化设计,通过对这两种结构日光温室的测试结果,分析在新疆独特气候下温室参数对日光温室性能的影响。温室保温性能验证实验表明:标准化设计的温室在南北疆喀什塔城两地分别在外界-10.7℃、-8.1℃低温环境下,其温室内冬至日的平均温度可达到19.9℃、22.8℃,最低温度为15.3℃、18.8℃,最高气温达到33℃、30.1℃,标准化设计温室保温效果好,并从实际生产角度充分验证了节能日光温室的使用性能。 相似文献
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日光温室建筑参数的多目标模糊优选 总被引:2,自引:1,他引:1
在日光温室设计中,建筑参数的选择要考虑温室建造成本、室内透光量、保温性能、冬季燃料费用、结构承载力、使用年限、土地利用率等因素。采用多目标模糊决策法对沈阳地区跨度7.5m、后坡长度2.0m、后坡仰角在25°~45°之间变化的不同日光温室建筑参数方案进行了优选。结果显示,围护结构材料相同、建筑参数不同的8个方案中跨度7.5m、后坡长度2.0m、后墙高2.2m、脊高3.7m的温室最优。 相似文献
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不同跨度组装式日光温室光热环境性能研究 总被引:1,自引:0,他引:1
为研究跨度对组装式日光温室温光环境的影响,选取8m、9m和10m跨度的组装式日光温室,以当地普通日光温室为对照,进行温室环境温度、光照性能观测和墙体热工性能分析。结果表明:各组装式日光温室墙体热稳定性远低于普通温室,平均最低温度较普通日光温室低1.27℃~5.30℃;组装式温室保温和采光性能随跨度增加而减小,1月份,8m跨度组装温室平均最低温度较9m和10m跨度温室高1.33℃和4.04℃,透光率高1.93%和7.67%,室内外最低温度差可达30.09℃;组装温室随跨度增大,室内温度变化越剧烈。综合分析认为,冬季组装式温室中8m跨度温室综合保温性能最好,组装式温室的保温性能随温室跨度的增加而下降,组装温室在没有辅助热源加温的情况下,不宜过度增加跨度。 相似文献
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日光温室冬季保温性能的好坏是制约菜农经济收入的重要因素之一,提高温室的保温性能、降低能耗是提高温室生产效益的最直接手段。该文以北京市延庆县为例,对当地土墙温室、土墙包砖温室和砖墙温室3种类型日光温室的温度进行了监测,对保温性能进行了对比分析,提出了日光温室增温保温效果的技术改进措施。 相似文献
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山东冬暖式日光温室建造技术及应用 总被引:1,自引:0,他引:1
山东冬暖式日光温室是在冬季以太阳光为主要能源,利用透明塑料薄膜、保温墙体等材料,人为创造蔬菜设施栽培的小气候环境,实现蔬菜等农作物反季节栽培的温室。近年来,随着设施农业的快速发展,山东冬暖式日光温室的建造技术不断改进和提高,应用面积越来越广。下面以山东近年来较有代表性的第Ⅳ代、第Ⅴ代冬暖式日光温室为例,对其建造技术及应用进行介绍。1.温室类型及结构山东省作为冬暖式日光 相似文献
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Overland water and salt flows in a set of rice paddies 总被引:1,自引:0,他引:1
E. Playn O. Prez-Coveta A. Martínez-Cob J. Herrero P. García-Navarro B. Latorre P. Brufau J. Garcs 《Agricultural Water Management》2008,95(6):645-658
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. 相似文献
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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。 相似文献
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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。 相似文献
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对《种子法》存在问题的探讨 总被引:1,自引:0,他引:1
李鹏 《农业机械化与电气化》2011,(6):129-130
《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。 相似文献
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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. 相似文献
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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。 相似文献
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Gunter Wriedt Marijn van der Velde Alberto Aloe Fayçal Bouraoui 《Agricultural Water Management》2009,96(5):771-789
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. 相似文献
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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。 相似文献
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车辆ABS控制算法的研究及探讨 总被引:1,自引:0,他引:1
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。 相似文献