钠离子对仔猪小肠刷状缘膜囊二肽跨膜转运的影响

为研究Na 在仔猪小肠Gly-Pro跨膜转运中的作用,采用同位素示踪及体外孵育技术,观察在不同Na 浓度梯度条件下Gly-Pro在仔猪小肠刷状缘膜囊(brush border membrane vesicles,BBMV)的跨膜转运量。结果表明:(1)用K 替代Na ,并没有降低Gly-Pro在BBMV中的转运量,在孵育前20min时间内,Gly-Pro的转运量稍稍提高;(2)Na 可使BBMV对L-丙氨酸的转运量提高到4.6倍,但不影响Gly-Pro的转运;二氢骆驼蓬碱显著地降低L-丙氨酸的转运,但对Gly-Pro的转运无影响。研究提示,Gly-Pro在仔猪小肠BBMV体系中的转运与Na 不存在依赖性的关系。     

信油2709喷施不同浓度普罗单效果研究

为探讨叶面肥对油菜生长的影响,进行了不同浓度叶面肥在杂交油菜信油2709上的效果研究.结果表明：在油菜苗期、蕾薹期、盛花期喷施不同浓度的叶面肥,均可提高油菜的产量和增强油菜的抗逆性.喷施3％浓度叶面肥对增加油菜产量及提高抗逆性效果最明显.     

文丘里施肥器控制性能试验分析

在水肥一体化滴灌设施中,为优选文丘里施肥器的最佳控制方式,以规格为32mm的并联式文丘里施肥器为对象,在文丘里施肥器的进水口、出水口和与水管的并联连接处3个位置安装球阀调节压差进行试验。试验结果表明,在进水口处调节压差,肥液质量分数低于13％时不能调节;在与水管的并联连接处调节压差,可实现对肥液质量分数的调节,但当压差...     

基于应力集中理论的磨削力模型

将应力集中理论引入磨削过程研究,分析了磨削过程中的应力集中现象,建立了基于应力集中的单颗磨粒磨削力模型,应用该模型分析了磨削力随磨粒磨损面积率的变化机理,并分别建立了单颗磨粒磨削法向力、切向力随磨粒磨损面积率变化的解析式,由解析式可知磨削法向力、切向力都与磨粒磨损面积率呈二次函数关系,得出了磨削后工件材料的累积残切厚度增大是磨削法向力增大的重要原因.在此基础上,结合实际生产中使用的砂轮特点,推导出了适用于实际磨削过程的基于应力集中的多颗磨粒砂轮磨削力随磨粒磨损面积率变化的解析式,用所建模型计算的结果与试验数据吻合较好.     

济南市鹊山水库氨氮污染模拟分析与应对方案

对济南市鹊山水库氨氮污染进行模拟分析,分析在不同工况与不同温度下,氨氮污染物的降解运移规律,预测了典型工况下,氨氮突发污染情况,并给出了相应的应对方案,为水库管理者对水库进行水量水质联合调度提供了依据。     

Deficit irrigation based on drought tolerance and root signalling in potatoes and tomatoes

Agriculture is a big consumer of fresh water in competition with other sectors of the society. Within the EU-project SAFIR new water-saving irrigation strategies were developed based on pot, semi-field and field experiments with potatoes (Solanum tuberosum L.), fresh tomatoes (Lycopersicon esculentum Mill.) and processing tomatoes as model plants. From the pot and semi-field experiments an ABA production model was developed for potatoes to optimize the ABA signalling; this was obtained by modelling the optimal level of soil drying for ABA production before re-irrigation in a crop growth model. The field irrigation guidelines were developed under temperate (Denmark), Mediterranean (Greece, Italy) and continental (Serbia, China) climatic conditions during summer. The field investigations on processing tomatoes were undertaken only in the Po valley (North Italy) on fine, textured soil. The investigations from several studies showed that gradual soil drying imposed by deficit irrigation (DI) or partial root zone drying irrigation (PRD) induced hydraulic and chemical signals from the root system resulting in partial stomatal closure, an increase in photosynthetic water use efficiency, and a slight reduction in top vegetative growth. Further PRD increased N-mineralization significantly beyond that from DI, causing a stay-green effect late in the growing season. In field potato and tomato experiments the water-saving irrigation strategies DI and PRD were able to save about 20-30% of the water used in fully irrigated plants. PRD increased marketable yield in potatoes significantly by 15% due to improved tuber size distribution. PRD increased antioxidant content significantly by approximately 10% in both potatoes and fresh tomatoes. Under a high temperature regime, full irrigation (FI) should be undertaken, as was clear from field observations in tomatoes. For tomatoes full irrigation should be undertaken for cooling effects when the night/day average temperature >26.5 °C or when air temperature >40 °C to avoid flower-dropping. The temperature threshold for potatoes is not clear. From three-year field drip irrigation experiments we found that under the establishment phase, both potatoes and tomatoes should be fully irrigated; however, during the later phases deficit irrigation might be applied as outlined below without causing significant yield reduction:

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Potatoes

°

After the end of tuber initiation, DI or PRD is applied at 70% of FI. During the last 14 days of the growth period, DI or PRD is applied at 50% of FI.

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Fresh tomatoes

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From the moment the 1st truce is developed, DI is applied at 85-80% of FI for two weeks. In the middle period, DI or PRD is applied at 70% of FI. During the last 14 days of the growth period, DI or PRD is applied at 50% of FI.

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Processing tomatoes

°

From transplanting to fruit setting at 4th-5th cluster, the PRD and DI threshold for re-irrigation is when the plant-available soil water content (ASWC) equals 0.7 (soil water potential, Ψ_soil = −90 kPa). During the late fruit development/ripening stage, 10% of red fruits, the threshold for re-irrigation for DI is when ASWC = 0.5 (Ψ_soil = −185 kPa) and for PRD when ASWC (dry side) = 0.4 (Ψ_{soil, dry side} = −270 kPa).

The findings during the SAFIR project might be used as a framework for implementing water-saving deficit irrigation under different local soil and climatic conditions.     

英德市农村饮水安全工程设计

英德市是广东省农村饮水安全工程的示范点,在饮水安全工程的建设过程中克服了诸多困难,取得了良好的效果,积累了不少经验。在水源点选择、管网布置、高水压处理等方面,设计人员都花费了大量时间进行调查、分析和研究,提出了适合于当地复杂条件的设计方案。对设计中遇到的问题和解决方法进行简要的总结,以供参考。     

不同地面结构育肥猪舍的恶臭排放影响因素分析

研究了冷、暖季节下生物发酵床、水泥实心、全缝隙3种不同地面结构的机械通风育肥猪舍的恶臭浓度、排放系数及地面结构、舍内温湿度、猪体重对恶臭浓度的影响.研究表明:猪舍的恶臭浓度与舍内温度、猪体重呈显著正相关(p＜0.05),恶臭浓度与相对湿度无显著相关性(p＞0.1);地面结构不同,恶臭浓度存在显著差异(p＜0.05);生物发酵床猪舍有助于恶臭减排,恶臭浓度最低,水泥实心地面猪舍的恶臭浓度最高,全缝隙地面猪舍的恶臭浓度居中;生物发酵床、全缝隙、水泥实心地面育肥猪舍的恶臭排放系数分别为(3.39±3.33)、(3.70±1.31)、(4.33±2.39) OU/(m2·s).     

单栋塑料温室内多因子综合CFD稳态模拟分析

为分析单栋塑料温室内的综合环境:气流场、温度场、湿度场、CO2浓度场,建立了包括温室内外空间、室内作物和土壤层等的温室环境几何模型。将温室内的湿空气看作水蒸气、CO2和干空气的混合气体,在分析温室中太阳辐射、作物与环境的质热交换,动量及质能传递过程的基础上,对单栋塑料温室内的环境因子进行了稳态模拟。温室内热辐射传递过程采用蒙特卡罗法模拟方法;将室内作物简化为连续固体换热模型,采用剪应力输运模型(SST)表述温室内的空气紊流。结果显示:温室通风对温度、湿度和CO2分布的影响很大,温室内部上风向温度低,湿度小,同时CO2浓度也不高;温室下风向作物冠层的环境未达到优化状态;模型的预测值低于实测值,但变化规律相似,温度、湿度、CO2含量的预测相对误差分别低于8%、6%和7%。     

电容式水流泥沙含量传感器温度补偿技术的研究

采用自行研制的电容传感器测量了水流中泥沙含量与传感器输出电压，研究了测量水流泥沙含量的温度补偿技术。结果表明，水流泥沙含量与传感器的输出电压呈线性关系，传感器的输出随温度的升高而逐渐增大；通过对温度的监测并由软件实现补偿的方法，可大大提高测量的精度；该方法能得到工作温度范围非标定条件下任一温度状态的输入－输出特性，可显著提高其温度稳定性。