基于响应曲面法的苦荞麸皮总黄酮提取工艺优化

测定了苦荞麸皮总黄酮的含量,并采用响应曲面法的Box-Behnken模式,对苦荞麸皮总黄酮超声波辅助提取工艺进行了研究。试验结果表明:苦荞麸皮总黄酮的质量分数为6.01%;超声波辅助提取苦荞麸皮总黄酮的各因素显著程度依次为乙醇体积分数、液料比、时间、温度;在本试验条件范围内建立的回归模型准确有效。采用响应曲面法优化得出的最佳工艺条件为温度65℃、乙醇体积分数90%、液料比40、超声时间30min,该工艺条件下苦荞麸皮总黄酮的提取率达95.10%。     

响应面法优化微波提取冬枣叶总黄酮及其抗氧化活性

采用微波法提取冬枣叶中总黄酮,研究了微波温度、微波时间、微波功率、液料比和乙醇体积分数对总黄酮提取率的影响。在单因素试验的基础上,采用Box-Behnken试验设计及响应面分析法对冬枣叶总黄酮的微波提取工艺进行优化,建立回归方程。得最佳提取工艺条件:微波温度70 ℃、微波时间6 min、微波功率500 W、液料比60∶1、乙醇体积分数50%,在此条件下,总黄酮提取率为3.760%,与响应面拟合所得方程的预测值3.757%符合良好。对提取的总黄酮抗氧化性研究表明,冬枣叶总黄酮对于羟基自由基清除能力较强,有一定的抗氧化活性。      

真姬菇菌丝体多糖碱提取工艺优化

借助Design-expert统计系统,采用中心组合试验法对真姬菇菌丝体多糖的碱提取工艺进行了优化研究.结果表明.以提取温度、提取时间、液料比、乙醇用量四因素为自变量,以多糖提取率为因变量,回归得到二次多项式模型极显著,模型校正决定系数为0.949 5,相关系数为0.984 7.当提取温度为73～76℃、提取时间为2.6～3.5 h、液料比为18.25--25 mL/g、乙醇用量为提取液体积的2.5～3.5倍时,多糖提取率最低为4.45%.当提取温度为76℃、提取时间3.24 h、液料比为23 mL/g、乙醇用量为提取液体积的3.5倍时,多糖提取率达最高值5.23%.     

山核桃外果皮黄酮提取与纯化

采用有机溶剂萃取法提取山核桃外果皮黄酮化合物,通过单因素和正交试验确定了最佳工艺参数.结果表明,提取溶剂为体积分数70％乙醇、提取时间4h、提取温度60℃、液料比15 mL/g条件下得黄酮化合物最高提取率为1.14％.采用硅胶色谱柱层析法纯化黄酮化合物,在液固比3 mL/g的条件下,体积分数70％乙醇以2 mL/min...     

花生根中白藜芦醇提取工艺的优化

白藜芦醇是一种重要的植物活性物质,具有多种生物活性.以白藜芦醇提取率为考察指标,探讨了花生根白藜芦醇的提取工艺.从4种常用试剂中选出乙醇作为提取剂,并在单因素试验的基础上.通过二次回归旋转组合设计试验,优化白藜芦醇提取的工艺参数.结果表明:乙醇体积分数61.48%、温度69.97℃、液料比38.94mL/g、浸提时间1 h、提取次数1次为最佳提取条件,在此条件下提取率为0.32%.     

青钱柳叶总黄酮超声辅助提取工艺优

为研究以乙醇为溶剂超声波辅助提取青钱柳叶总黄酮的工艺,在单因素试验的基础上,采用四因素二次回归正交旋转组合设计,以液料比、超声处理时间、超声功率、溶剂体积分数为考察因素,优选了超声波辅助提取青钱柳叶总黄酮的最佳工艺.结果表明各因素对提取率的影响大小依次为:超声处理时间、溶剂体积分数、液料比、超声功率.最佳工艺条件为液料比55mL/g,超声处理时间34min,超声功率720W,溶剂体积分数60%,在此最佳条件下,总黄酮的得率为86.63%,优化工艺稳定,提取率也较高,试验验证结果与模型预测值相符.     

苦瓜黄酮提取及抑菌性研究

采用超声波提取苦瓜黄酮,并对其抑菌性做了研究。通过单因素和正交试验得出最佳提取工艺为:乙醇体积分数80%、提取时间30min和料液比1∶45,此条件下苦瓜黄酮提取率为4.3%。采用滤纸片扩散法进行抑菌试验,结果表明:苦瓜黄酮对金黄色葡萄球菌和枯草芽孢杆菌均有很好的抑菌性。     

牛蒡叶抗氧化物质的提取工艺

为优化牛蒡叶抗氧化活性物质的提取工艺,通过单因素试验考察了乙醇体积分数、提取时间、提取温度和液料比对提取物清除DPPH自由基活性能力的影响,在单因素试验的基础上,通过Box-Behnken中心组合试验设计对提取工艺进行优化,获得了牛蒡叶抗氧化活性物质提取条件的最佳工艺。结果表明:最佳提取工艺条件为乙醇体积分数58.6%、提取时间36.3min、提取温度52℃和液料比22mL/g,在此条件下牛蒡叶提取物对DPPH自由基清除率的最大理论值为97.40%。对此优化条件进行验证,重复3次,实测平均清除率为97.34%,表明该回归模型具有较好的预测性能,可用于指导生产实践。     

高效生物膜反应装置中加热恒温系统的设计

沼气料液合适的发酵温度是中温发酵和高温发酵。与传统的常温发酵相比,中温发酵和高温发酵产生沼气具有稳定性和高效性的特点,但却对温度的稳定性要求极为严格。为此,基于沼气在发酵过程中对温度高稳定性的要求,结合新疆地区光照时间长、干旱少雨、适于开发利用太阳能等独特的地域特征,设计了以太阳能为热源的自动加热恒温系统,以确保反应装置能够高效地生成沼气。     

油用萝卜籽中黄酮提取工艺优化

以油用萝卜籽为研究对象,以乙醇为溶剂,采用超声波辅助法提取油用萝卜籽中的总黄酮化合物,利用紫外分光光度法测定总黄酮的提取含量。在单因素试验的基础上,用响应面法优化提取工艺条件。通过分析料液比、乙醇浓度、超声温度和超声时间4个因素及两两因素间对总黄酮提取含量的影响,得出影响最大的是超声温度,其次是超声时间,接着是料液比,最后是乙醇浓度。当料液比1∶25 g/mL,乙醇浓度70%,超声温度53 ℃,超声时间28 min时,提取率最高,此时总黄酮含量为15.18 mg/g。与模型预测值15.15 mg/g接近,表明此工艺较为可靠,有一定的参考价值。      

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。