羟丙基甲基纤维素高吸水性树脂制备与性能表征

以羟丙基甲基纤维素为骨架材料,丙烯酸为接枝共聚单体,过硫酸铵-亚硫酸氢钠为引发剂,聚乙二醇200二丙烯酸酯为交联剂,在微波辐射的条件下通过接枝聚合反应制备高吸水性树脂,并对高吸水性树脂的吸液倍率、吸液速率、保水性能以及红外光谱、热稳定性、表观形态进行表征。结果表明,羟丙基甲基纤维素与丙烯酸质量比为1/7、中和度为65%、引发剂与丙烯酸质量分数为1%、交联剂与丙烯酸质量分数为0. 4%、反应时间为4. 5 min是较优的制备方法,该条件下制备的羟丙基甲基纤维素高吸水性树脂吸水倍率可达497. 13 g/g,吸盐倍率为61. 70 g/g;35℃条件下,该高吸水性树脂可保水48 h以上;重复使用6次后,该高吸水性树脂仍具有较高的吸液倍率。     

羟乙基纤维素与聚丙烯酸钠接枝共聚及其溶胀行为

采用微波法合成羟乙基纤维素/聚丙烯酸钠接枝共聚物(HEC-g-PAA),考察了单体中和度、单体用量、引发剂质量浓度等因素对接枝率和吸水率的影响,并研究了不同粒度HEC-g-PAA的溶胀行为.结果表明,HEC-g-PAA的溶胀过程属于非Fick扩散过程,链段松弛是树脂吸水的主要原因.     

四种不同类型保水剂的基本性能分析

为了对比不同类型保水剂的基本性能,以聚丙烯酰胺-无机矿物型、聚丙烯酰胺型、聚丙烯酸型和淀粉-丙烯酸共聚型为试验材料,通过室内试验,探究了不同保水剂的吸水能力、保水能力以及在不同离子溶液中的吸水性能.试验结果表明:保水剂在去离子水中吸水90 min后逐渐饱和,其中淀粉-丙烯酸共聚型吸水倍率为777.43 g/g,在所有处...     

玉米秸秆沼渣土壤保水剂制备与性能表征

以玉米秸秆沼渣为试验原料,采用硝酸-乙醇法提纯、丙烯酸为接枝单体、过硫酸钾为自由基引发剂、N,N'-亚甲基双丙烯酰胺为交联剂,在微波加热条件下,通过接枝聚合反应制备沼渣纤维素土壤保水剂,并对合成产物的吸液倍率、保水性能、红外光谱和表面形态进行表征。结果表明,单体丙烯酸与秸秆沼渣纤维素的质量比为7,中和度为70.0%,引发剂与单体质量比为2.0%,交联剂与单体质量比为0.1%,合成的秸秆纤维素保水剂具有较高的吸水倍率。红外吸收光谱中,沼渣纤维素保水剂在波数1 200 cm~(-1)出现了丙烯酸的C—O伸缩峰,在波数1 350 cm~(-1)附近出现了丙烯酸的O—H弯曲振动区。中和后的—COO-削弱了丙烯酸中的C=O,使C=O的吸收峰在波数1 557.98 cm~(-1)处出现,表明接枝成功。利用玉米秸秆沼渣中的纤维素进行接枝改性制备土壤保水剂,是实现农业废弃物资源化高效利用的一种新方法。     

一种新型保水剂的制备及对肥料吸附性能研究

以膨润土和丙烯酸为原料,N,N′-亚甲基双丙烯酰胺为交联剂,过硫酸钾为引发剂,在微波辐射下制备了一种新型保水剂,其吸蒸馏水倍率为890g/g,吸0.9%NaCl溶液倍率为95g/g,并用红外光谱、电镜扫描对产物进行了表征。同时,研究了几种肥料对该保水剂吸水倍率的影响及其对肥料的吸附规律。结果表明,在一定范围内,保水剂的吸水倍率随着肥料体积质量的增加而降低,保水剂对肥料的吸附量随体积质量的增大而增加。     

PAAM高吸水树脂吸水保水性能

采用自制聚(丙烯酸-丙烯酰胺)高吸水性树脂(PAAM)研究了0.9%食盐水、人工尿液、人工血液中吸液性能,室内自然环境下PAAM在泥土、河沙、泥土/河沙(1:1)中对自来水、0.9%食盐水的保水性能.结果表明,吸液初期(5 min内),PAAM在0.9%食盐水、人工尿液和人工血液中的吸水倍率随时间增加而迅速增加,10 min后吸水倍率达平衡,且吸水倍率顺序为0.9%食盐水>>人工血液>人工尿液.其他条件相同时,随PAAM的用量增加,土壤保水率增大;随时间增长,土壤保水性能下降;自来水中的保水率优于食盐水的.     

硼缓释型高吸水性树脂制备与性能表征

以硼酸、丙三醇为原料,通过微波酯化法制备了硼酸双甘酯。以硼酸双甘酯和丙烯酰氯为原料合成了硼酸甘油丙烯酯,以此作为含硼功能单体,成功制备了以羟丙基甲基纤维素为骨架的硼缓释型高吸水性树脂。根据吸水倍率筛选含硼功能单体最佳添加量,并对产物的吸液倍率、吸液速率、保水性能以及基团结构和表观形貌进行了表征。由红外光谱曲线可以看出,试验成功制备了具有双键结构的硼酸甘油丙烯酯,并通过接枝聚合反应合成了含硼高吸水性树脂;当含硼功能单体添加量为丙烯酸质量的1%时,羟丙基甲基纤维素含硼高吸水性树脂吸水倍率为344. 06 g/g、吸盐倍率为44. 71 g/g; 35℃条件下,该含硼高吸水性树脂可保水72 h;重复使用6次后,该高吸水性树脂重复吸水率仍可达到60%以上,重复吸盐率仍可达到40%以上;该高吸水性树脂具有良好的硼缓释性,在去离子水中可持续缓释10 d,缓释硼总质量达182. 77μg,在育苗基质中可持续释放25 d,当添加量为育苗基质质量的0. 5%时,混合基质淋溶硼量比普通基质多0. 80μg/g。此外,羟丙基甲基纤维素含硼高吸水性树脂还具有良好的热稳定性,其表观形貌特征有利于促进对液体的吸收。     

苯乙烯型阳离子交换树脂催化废煎炸油的酯化反应

以液体石蜡、邻苯二甲酸二丁酯为混合致孔剂,采用悬浮聚合法制备多孔聚苯乙烯-二乙烯苯,磺化后得到磺酸型阳离子交换树脂。利用SEM/EDS、BET、IR等手段对其形貌、磺化程度进行表征,并通过酸值为63.0 mg/g(以KOH计)煎炸油的酯化反应考察催化剂的活性。结果表明:磺酸根基团成功接到PS分子链上;在聚合条件为360 r/min、1.0%分散剂、1.0%引发剂、75℃保温4 h、升温至85℃保温6 h时,混合致孔剂的最佳添加量为40.0%液体石蜡、50.0%邻苯二甲酸二丁酯;在磺化条件为二氯乙烷1.0 m L/g、硫酸5.0 m L/g、70℃磺化1 h后升温至80~85℃磺化3 h时的最佳溶胀时间为1 h、硫酸体积分数98%,得到阳离子交换树脂W2的最大交换容量为5.2 mmol/g;在40.0%甲醇、10.0%W2、70℃搅拌下酯化反应1.5 h,W2的破碎率仅10.0%,FFA转化率达到86.8%,优于市售阳离子交换树脂PC101,且可重复使用5次。     

机械活化花生壳-丙烯酸接枝共聚合成高吸水性树脂

采用搅拌球磨对花生壳进行机械活化,以不同活化时间的花生壳为原料,过硫酸铵和亚硫酸钠为引发剂,通过水溶液聚合法花生壳接枝丙烯酸合成高吸水性树脂。考察了活化时间、单体与花生壳质量比、交联剂用量、引发剂用量和反应温度等因素对吸水率的影响。活化90min的花生壳制得的产品去离子吸水率和0.9%氯化钠溶液的吸水率分别为1276g/g和136g/g,相同条件下未活化的仅为675g/g与71g/g。     

颗粒活性炭用于城市污水的深度处理与活性炭的微波再生

利用颗粒活性炭连续流试验对城市污水处理厂的出水进行深度处理,COD出水浓度达到6.8mg/L,满足地表水环境质量标准(GB3838-88)Ⅱ类标准,深度处理是可行的。当活性炭达到饱和时,必须进行再生。本实验以碘吸附值作为指标,通过单因素实验考查了不同微波功率、不同微波辐照时间对颗粒活性炭的再生损耗率、性能恢复率、综合恢复率的影响,并分析其呈现的规律和原因。实验结果表明,在微波功率为464 W、辐照时间为2min时,活性炭(0.8g)性能恢复率达到最大值,为102.53%;在功率为464W、时间为2min时,活性炭(0.8g)综合恢复率最佳,为94.90%。     

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。