冷冻干燥中升华界面的临界温度实验

利用冻干显微镜（FDM）研究了二元水溶液冷冻干燥过程中升华界面的临界温度,采用差示扫描量热法（DSC）测量了溶液的共晶熔融温度和最大冻结浓缩溶液的玻璃化转变温度。实验结果表明,对于降温时发生共晶的溶液,临界温度为共晶熔融温度,否则将发生融化;对于降温时发生玻璃化转变的溶液,临界温度为塌陷温度,否则将发生塌陷。对于质量分数为5%蔗糖、10%葡萄糖、10%麦芽糖、10%聚乙烯吡咯烷酮（PVP）二元水溶液,微塌陷温度与塌陷温度的差值在2℃以内,微塌陷温度比玻璃化转变温度高     

冷冻干燥中升华界面的临界温度实验

利用冻干显微镜(FDM)研究了二元水溶液冷冻干燥过程中升华界面的临界温度,采用差示扫描量热法(DSC)测量了溶液的共晶熔融温度和最大冻结浓缩溶液的玻璃化转变温度.实验结果表明,对于降温时发生共晶的溶液,临界温度为共晶熔融温度,否则将发生融化;对于降温时发生玻璃化转变的溶液,临界温度为塌陷温度,否则将发生塌陷.对于质量分数为5%蔗糖、10%葡萄糖、10%麦芽糖、10%聚乙烯吡咯烷酮(PVP)二元水溶液,微塌陷温度与塌陷温度的差值在2℃以内,微塌陷温度比玻璃化转变温度高1～3℃.     

中空纤维超滤膜分离菜籽饼粕中蛋白质的试验

研究了利用中空纤维超滤膜分离菜籽饼粕中蛋白质的可行性。基于超滤机理分析了超滤过程中的操作压力、溶液的温度、质量分数以及pH值等参数对膜通量的影响。在用5%的食盐溶液提取的基础上,通过超滤试验得到最佳工艺条件,操作压力为0.2MPa,溶液的温度、质量分数和pH值分别为40℃、7%和10。最后提出了超滤膜污染的预防及清洗方法。试验结果表明利用中空纤维超滤膜分离菜籽饼粕中蛋白质的方法是可行的。     

不同质量分数NaCl和温度对黄原胶减阻特性影响的试验研究

为研究NaCl环境中黄原胶的减阻特性及温度对其性能的影响,通过在光滑圆管内进行不同质量分数NaCl的黄原胶溶液减阻特性试验,得到不同质量分数XG/NaCl溶液的减阻率随流动雷诺数的变化关系,并与黄原胶水溶液的减阻特性进行了对比.结果表明：当黄原胶稀溶液质量分数0.01%～0.02%时,NaCl质量分数对溶液减阻率随雷诺数变化的影响较大,当黄原胶浓溶液质量分数0.05%～0.06%时,该影响变小;高质量分数NaCl条件下,黄原胶质量分数低于0.03%时大致遵循B型减阻类型;当黄原胶溶液质量分数大于或等于0.03%时,溶液具有从低雷诺数下A型减阻到高雷诺数下B型减阻的转换特征;黄原胶溶液的减阻率在低雷诺数时对温度的变化较为敏感,高雷诺数下的减阻效果受温度影响较小.     

秸秆水解液还原糖组分特征及产甲烷特性

为认识预处理方式对秸秆水解液中还原糖组分特征和产甲烷特性的影响,对稻秸分别进行酸、碱预处理：在HCl质量分数较高（9%和7%）时,所得还原糖中木糖所占比例大;在Ca(OH)2质量浓度（2 g/L和4 g/L）较低时,前48 h葡萄糖比例较高。以配水实验研究不同比例的葡萄糖和木糖混合液的产甲烷特性,混合物中葡萄糖摩尔分数对产气特性影响显著,随葡萄糖摩尔分数的增加,产气速率增加,葡萄糖摩尔分数100%时对应最低的产气率191.75 mL/g,25%实验组获得最高产气率633.14 mL/g和最高能量转换效率26.40%,纯木糖发酵存在一定的初期产气迟滞。     

不同溶氧量对油麦菜生长、光合指标和产量的影响

通过大棚立体种植油麦菜试验,以灌溉水中溶氧量为试验因素,研究不同溶氧量(T1处理6.8 mg/L、T2处理8 mg/L、T3处理7.4 mg/L、T4处理1.2 mg/L)对油麦菜生长量、光合指标、植株鲜质量、干质量和产量的影响。结果表明,(1)不同溶氧量对油麦菜株高、叶片数和茎粗有显著性影响;各处理株高均值次序为:T2处理T3处理T1处理T4处理,叶片数均值次序与株高的相同;(2)不同溶氧量对叶绿素质量分数、净光合速率、蒸腾速率、气孔开度有显著性影响,但是对胞间CO2摩尔分数影响并不显著;(3)不同溶氧量对单株鲜质量和干质量影响显著,T2处理的单株鲜质量和干质量最大,分别为56.25、10.71 g;T4处理的最小,分别为42.64、3.52 g;T1、T2、T3处理与T4处理相比产量分别提高了13.2%、22.6%、28.3%。以产量为研究目标时,7.4 mg/L溶氧量+灌水定额45 m3/hm2为最佳组合。     

黄糊精/秸秆纤维增强复合材料的吸湿性能分

试验分析了黄糊精/秸秆纤维复合材料在不同相对湿度下的吸湿率,并对复合材料的吸湿率数据进行一元非线性回归拟合得ω=α+bt~c,吸湿速率v=dw/dt=bct~(c-1),建立了吸湿率和吸湿速率的数学模型,分析了每种秸秆纤维复合材料在相同的相对湿度下的吸湿率曲线.在100 g秸秆纤维、40 g水、20 g黄糊精、热压温度为170℃、热压压力为4.2MPa、热压时间为30min和100 g秸秆纤维、40 g水、10 g黄糊精、热压温度为170℃、热压压力为9.8 MPa、热压时间为20 min两种条件下制备了的两种黄糊精/秸秆纤维复合材料,试验得出上述两种复合材料吸湿率较小,表明两种秸秆纤维复合材料耐水性好.在黄糊精/秸秆纤维复合材料制备中,应重点注意热压温度因素,它对复合材料的耐水性影响较大.     

水磁化处理对水肥溶液中黏性颗粒絮凝沉降的影响

【目的】探究水磁化处理对富含黏性颗粒水肥溶液絮凝沉降过程的影响。【方法】配置5种质量浓度的高岭土悬浮液（0.5、1.0、1.5、3.0、5.0 g/L）和3种质量浓度（0.25、0.5 g/L和0.75 g/L）的硫酸钾、尿素、复合肥混合液共14种,分别在4种不同磁化强度（W0:0 T、W1:0.2 T、W2:0.4 T和W3:0.6 T）下,测定4 h内沉降量筒底端10cm高处的浊度、中值沉速、沉降泥沙机械组成、水样zeta电位、p H值、电导率和黏滞系数等的变化。【结果】与未磁化处理相比,磁化后黏性颗粒的絮凝作用有所增强、沉降速率加快（p<0.01）;磁化强度为0.4 T(W2)时,黏性颗粒的絮凝作用最强,沉降泥沙的中值粒径比未磁化处理最高可增加14.7%,其黏粒占比最高可减少25.0%,zeta电位最高可降低68.7%。当水中加入不同肥料时,磁化对沉降泥沙中值粒径、黏粒占比和水样zeta电位值的影响不同,施加硫酸钾肥时磁化的影响效果最大,施加尿素时的影响效果最小。【结论】灌溉水磁化处理可显著促进黏性颗粒的絮凝作用和沉降速率,建议用磁化水灌溉或者输水时,应定期冲洗管网系统,排...     

电子舌在甜菊糖甜味特性评价中的应用

采用电子舌技术结合主成分分析,以蔗糖为参比物,对5种不同组成的甜菊糖样品(RA95、RA97、RA99、RA/RB(90/10)、RA/RD(90/7)),进行了甜味特性评价研究,将评价结果与感官评价结果进行了对比。甜菊糖溶液质量浓度0.2~0.8 g/L时,等同甜度的蔗糖溶液质量溶度为0.03~0.09 g/m L,相对蔗糖甜度倍数为90~220,在口腔内的甜味持续时间为10~60 s,质量浓度1.2 g/L的5种甜菊糖溶液均呈现出明显苦味。电子舌可以准确识别5种不同类型甜菊糖样品,判别指数为100。在主成分分析得分图的PC1和PC2轴上,电子舌能够识别不同质量浓度的蔗糖和甜菊糖溶液,电子舌对相同质量浓度的甜菊糖溶液甜味强度识别结果从大到小依次为RA/RD(90/7)、RA95、RA/RB(90/10)和RA99、RA97、RA95,识别结果与感官评价结果一致。通过计算主成分得分图上的组间距离,电子舌判定3种RA系列甜菊糖与蔗糖的相似度最高的为RA99,其次为RA97和RA95。结果表明,电子舌技术在代替人工感官进行甜味评价方面有很好的应用前景。     

响应面法优化改性玉米粉的复合酶法制备工艺

本试验采用复合酶法制备改性玉米粉,以改性玉米粉的综合感官评分作为评价指标对复合酶法制备工艺进行优化。运用SAS软件及响应面法得到最佳工艺参数:恒定试验底物质量浓度0.5g/mL、中性蛋白酶质量分数0.12%和pH值6.5,将中性蛋白酶和一定质量分数的α-淀粉酶同时加入溶液,浸泡温度59.9℃、α-淀粉酶质量分数0.043%和酶解时间1.18h。     

蕨菜真空冷冻干燥工艺参数的优化试验

考察干燥因子对真空冷冻干燥蕨菜品质的影响,用二次正交旋转组合设计的试验方法,分析搁板加热温度、干燥室压力和物料层厚度对蕨菜Vc含量的影响规律,建立了冻干因子与Vc含量的回归模型.利用双因素分析法分析了各因素与试验指标的关系,确定各因素在二次非线性模型中的主次顺序.试验结果分析表明.干燥室压力对蕨菜冻干制品的品质影响最大,搁板加热温度次之.物料厚度的影响最小.并利用非线性优化理论确定了搁板加热温度为42.5℃、干燥室压力为55 Pa、物料厚度为16.3mm时,蕨菜的Vc质量比可达2.387mg/g.     

基于干燥动力学特性的冷冻干燥过程判

判断冷冻干燥过程的升华干燥结束点和解吸干燥结束点,对冷冻干燥过程的优化控制有重要意义.以富士苹果为试验材料,在JDG-0.2型真空冻干试验机上进行了冷冻干燥动力学特性试验.采用自制的物料水分在线测量系统,实时测量和绘制苹果块在冷冻干燥过程中的含水率及其变化曲线,根据测量数据分析了物料冷冻干燥动力学特性,提出了升华干燥结束点和解吸干燥结束点的判别方法,便于冷冻干燥过程参数的优化控制.     

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。