共查询到20条相似文献，搜索用时 62 毫秒
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通过单因素试验和均匀试验,分别考察了超临界CO2萃取黑芝麻和脱皮白芝麻的最佳工艺条件。结果表明:在CO2流量18L/h、原料粒径范围20～40目,超临界CO2萃取黑芝麻的最佳工艺条件为萃取压力25MPa、萃取温度50℃和萃取时间240min;超临界CO2萃取脱皮白芝麻的最佳工艺条件为萃取压力25.5MPa、萃取温度53℃和萃取时间240min。在最佳工艺条件下,油脂萃取率分别为87.7%和95.3%,脱皮白芝麻油色泽Y12.1、R0.5,酸值<0.6(KOH)/(mg/g),过氧化值2.7mmol/kg均优于黑芝麻油。超临界CO2萃取的芝麻毛油品质明显优于压榨法和浸出法制取油。 相似文献
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牡丹籽油超临界二氧化碳萃取工艺 总被引：3，自引：1，他引：2
以牡丹籽为原料,利用超临界CO_2萃取提取牡丹籽油.采用单因素试验对影响牡丹籽油得率的5个影响因素(筛分粒度、CO_2流量、压力、温度和时间)进行考察.以油得率为响应目标,对3个主要影响因素(筛分粒度、压力和温度)运用中心复合设计法,并经响应面法优化分析得到二次多项式回归方程预测模型,确定了超临界C_O2萃取牡丹籽油的最佳条件为:筛分粒度60目,CO_2流量20L/h,压力35MPa,温度45℃,时间120min.在较优提取条件下,牡丹籽油得率可达到24.22%.GC-MS结果表明牡丹籽油中富含不饱和脂肪酸,其中亚油酸和亚麻酸的含量分别为23.34%和66.85%. 相似文献
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本文采用CO2超临界流体萃取技术对沙棘籽及果渣进行脱脂,通过正交试验确定萃取的最佳工艺条件:萃取压力25MPa、萃取温度为40℃、萃取120min和CO2流量为15L/min,在此工艺下能够脱除脂肪17.82%,萃取率可达到94.18%,并着重探讨了各萃取条件对沙棘籽及果渣脱脂效果的影响。 相似文献
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本研究以哈密瓜籽油的最大提取率为目标,研究了超临界CO2萃取哈密瓜籽油的提取工艺,分析了萃取压力、萃取温度、萃取时间对哈密瓜籽油提取率的影响,并通过正交试验得到了最佳的提取条件:萃取压力为30MPa、萃取温度为40℃、萃取时间为2h,在此条件下哈密瓜籽油的萃取得率为25.93%。对超临界萃取哈密瓜籽油进行物理化学分析和GC-MS分析表明,超临界萃取哈密瓜籽油工艺稳定可靠,具有极高的应用价值。 相似文献
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大豆异黄酮超临界流体萃取工艺与动力学模型 总被引：1，自引：0，他引：1
通过单因素和L9(34)正交试验确定了超临界流体萃取大豆异黄酮最佳萃取条件为：CO2流量8L/h,静萃取120min,动萃取60min,每克脱脂豆粕的乙醇用量3mL,萃取温度55℃,萃取压力30MPa。借鉴固定床层吸附/脱附理论建立了萃取动力学模型,并采用BP神经网络和试差法确定了模型参数kLa,确定参数后的动力学模型较为精确地定量描述了萃取床层的溶质分布。 相似文献
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基于超临界流体萃取原理,通过单因素和正交试验研究了超临界CO2萃取玫瑰精油的最佳工艺条件。原料粒度60目,流量18L/h,萃取时间1.5h,温度40℃,压力16MPa。GC/MS联用仪对产物进行分析,共检测出60种化合物,并给出它们的百分含量,通过谱库检索,结合裂解机理,参照ISO9842-2003标准对其中17种重要化合物进行鉴别,主要产物含量与ISO标准要求的含量基本相当。 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