沙苑子粗多糖的提取和脱蛋白方法的比较研究

用水提法提取沙苑子多糖,并对其脱蛋白方法进行了比较研究。结果表明,水提沙苑子多糖的最佳条件是:提取温度为65℃,提取时间为3h,料液比为1∶15,提取次数为3次。在该提取条件下,可以得到最高粗多糖得率96.9g/kg;分别采用sevag法、酶法、三氯乙酸(TCA)法和sevag法结合酶法等方法脱去沙苑子粗多糖提取物中的蛋白质。酶法脱蛋白的最佳条件为:温度为45℃,时间为1h,酶量为0.4g,pH值为7.0。结果表明,用sevag法结合酶法脱蛋白的效率最高,为87.5%,且多糖损失率较低,为14.9%。     

Use of saline aquaculture wastewater to irrigate salt-tolerant Jerusalem artichoke and sunflower in semiarid coastal zones of China

In 2004 and 2005, the feasibility of agricultural use of saline aquaculture wastewater for irrigation of Jerusalem artichoke and sunflower was conducted in the Laizhou region using saline aquaculture wastewater mixed with brackish groundwater at different ratios. Six treatments with different electrical conductivities (EC) were included in the experiment: CK1 (rainfed), CK2 (irrigation with freshwater, EC of 0.02 dS m⁻¹), and saline aquaculture wastewater (EC of 39.2 dS m⁻¹) mixed with brackish groundwater (EC of 4.4 dS m⁻¹) at volumetric ratios of 1:1, 1:2, 1:3, and 1:4 with corresponding EC of 22.0, 16.1, 13.2, and 11.4 dS m⁻¹. Soil electrical conductivity (ECe) in the saline aquaculture wastewater irrigation treatments was significantly higher (P ≤ 0.05) than that in the rainfed or freshwater irrigation treatments, and the maximum value occurred in the 22.0 dS m⁻¹ treatment. The sodium adsorption ratio (SAR) ranged from 4.1 to 11.7 mmol^1/2 L^−1/2 and increased with decreasing salinity of irrigation water. The biomass of Jerusalem artichoke significantly decreased (P ≤ 0.05) when irrigated with saline aquaculture wastewater compared to the rainfed or freshwater irrigation treatments; however, the effect of salinity on root biomass was much smaller than the aerial parts. Concomitantly, the highest tuber yield of Jerusalem artichoke occurred in the 11.4 dS m⁻¹ treatment, while the highest seed yield of sunflower occurred in the rainfed treatment. Additionally, nitrogen and phosphorus concentrations of Jerusalem artichoke were significantly higher in the 11.4 dS m⁻¹ treatment than the other treatments. This study demonstrated that properly diluted saline aquaculture wastewater can be used successfully to irrigate Jerusalem artichoke with higher economic yield and nutrient removal, but not sunflower due to the difference in salt tolerance.     

鲜食玉米果穗收获负压除杂装置参数优化与试验

针对现有鲜食玉米收获机在收获果穗时,果穗中含有茎叶等杂质,影响运输、贮存和后续加工等问题,采用轴流风机负压除杂技术去除果穗中的茎秆和茎叶等杂质,同时在除杂装置内增加动、定刀,切碎杂质,便于后续的打包回收利用,并对风机负压除杂装置进行了性能分析和参数优化。通过对动、定刀进行动力学分析,对动、定刀数和刀间隙进行分析,确定了该装置的风机转速范围为1326~1573r/min,动、定刀间隙20mm,定刀数为3~8。采用二次回归正交组合试验方案,以风机转速、定刀数、喂入量为试验因素,以果穗含杂率和茎秆切碎长度合格率为试验指标进行台架试验,通过分析各因素对指标贡献率,得到影响茎秆切碎长度合格率的主次顺序为喂入量、风机转速、定刀数,影响果穗含杂率的主次顺序为风机转速、喂入量、定刀数。建立了参数优化数学模型,利用Optimization模块优化得出,当风机转速为1524r/min、单排定刀数为4、喂入量为7.6kg/s时,茎秆切碎长度合格率为96.8%,果穗含杂率为0.69%。对优化后的参数组合进行了5组验证试验,得到茎秆切碎长度合格率平均值为96.2%,果穗含杂率平均值为0.71%。相比于传统收获机,该装置使果穗含杂率降低了23.3%,说明该优化参数能够满足鲜食玉米果穗收获和茎叶青贮相关技术要求。     

城市污水生物脱氮除磷技术的发展

生物脱氮除磷技术（Biological NutrientRemoval)的研究和应用已逾40年。本文围绕着脱氮除磷理论的发展和自控技术在污水处理领域的应用,论述了生物脱氮除磷技术的发展情况,并重点介绍了几项国内外最新的脱氮除磷技术。     

氧化塘深度对猪场厌氧消化液后处理的影响

采用小试装置对3个不同深度氧化塘处理猪场厌氧消化液的效果进行了研究,结果表明:当平均气温为21.9℃,停留时间在80 ～110天,进水负荷为0.05 m3·m-2d-1的条件下,氧化塘对NH4-N的去除率达到了90％以上,CODcr,TP的去除率分别为50％,40％.硝化作用和藻类的吸收是氧化塘去除NH4-N的主要方式,沉淀作用则是CODcr和TP的主要去除方式,在较长停留时间下,微生物对于溶解性CODcr的分解和同化也能提供一定的去除效果.当平均气温为21.9℃,在表面负荷为0.05 m3·m-2d-1的条件下,有效深度为0.3m和0.7m的氧化塘面积去除负荷分别为1.41 g·m-2d-1,1.49 g·m-2d-1,容积去除负荷分别为4.7g·m -3d-1,2.8g·m-3d-1.虽然较深氧化塘具有较高的面积去除负荷,但较浅的氧化塘却有更高的容积去除负荷.     

两种不同布水方式对生物砂滤池去除厌氧消化液氨氮的影响

在实验室条件下,采用试验生物砂滤柱模拟生物砂滤池系统,研究了雾化和滴渗布水方式对生物砂滤池去除猪场厌氧消化液氨氮的影响,结果表明:在进水水力负荷为0.057 m3.m-2d-1,氨氮平均浓度分别为293 mg.L-1,513 mg.L-1,553 mg.L-1时,雾化布水生物砂滤池对氨氮的平均去除率分别为98.8%,87.4%,75.1%,出水氨氮平均浓度分别为3.61 mg.L-1,64.7 mg.L-1,138 mg.L-1,平均去除负荷分别为16.4 g.m-2d-1,25.4g.m-2d-1,23.5 g.m-2d-1;滴渗布水生物砂滤池对氨氮的平均去除率分别为77.4%,71.4%,59.3%,出水氨氮平均浓度分别为66.3 mg.L-1,147 mg.L-1,225 mg.L-1,平均去除负荷分别为12.9 g.m-2d-1,20.7 g.m-2d-1,18.6 g.m-2d-1;雾化布水可以提高生物砂滤池氨氮的去除率、去除负荷,降低出水氨氮浓度;滴渗布水在进水氨氮平均浓度293 mg.L-1,雾化布水进水氨氮平均浓度293 mg.L-1,513 mg.L-1的条件下,出水氨氮平均浓度可达到《畜禽...     

半咸水人工湿地净化越冬养殖循环水的效果

为拓展人工湿地在水产养殖上的应用,该文研究了半咸水人工湿地的循环水越冬系统中暗纹东方鲀越冬养殖效果和净化效能。结果表明,经过166d越冬养殖,暗纹东方鲀越冬成活率(76.94±13.87)%,饵料系数5.49±1.77。在无任何外源能源加温的情况下,系统水温保持在暗纹东方鲀幼鱼的生存最低温度以上。在半咸水环境下(7.6‰～9.9‰),人工湿地对养殖水有良好的净化效果:总氮去除率为30.5%、总氨氮为69.6%、亚硝酸盐为96.1%、硝酸盐为9.7%、总磷为18.4%、COD为38.8%、总悬浮物为79.7%,循环水经过人工湿地后水质符合国家渔业用水标准;越冬期间,越冬养殖池水质状况良好;除TN和NO3-N在越冬期间的去除率比在夏季的明显低外,其他主要污染物的去除率与夏季比较没有明显变化。在试验负载范围内,系统去除量随进水污染负载量的增加而增加;通过建立预测模型预测出湿地养殖面积比值0.36～0.97,与实际值1.26相比,养殖密度尚有提高的空间。因此,人工湿地能持续有效地去除暗纹东方鲀越冬循环水养殖系统中的主要污染物,说明该系统能在越冬养殖生产实际应用。     

基于流固耦合的除杂风机应力应变及模态研究

叶轮是除杂风机的重要部件之一,叶轮在运行中的应力应变对除杂风机的安全运行有着重要的影响,而叶轮振动是风机的常见故障,所以流固耦合条件下的除杂风机叶轮变形及振动分析对甘蔗收获机除杂风机的安全有着重要的意义。为此,采用有限元分析软件Ansys Workbench对除杂风机叶轮进行了单向流固耦合计算分析,结果表明:叶轮在流固耦合作用下会发生弯曲扭振变形,最大应力分布在叶片与轮毂的交界处,最大应变分布在叶片外缘处;所设计的叶轮最大应力为21.48MPa,小于材料极限应力,而工作转速也远离振动转速,均满足工作要求。该研究为甘蔗收获机的除杂风机设计提供了参考。     

花生壳活性炭吸附染料废水中结晶紫的研究

利用磷酸处理微波照射制备花生壳活性炭,以一定浓度的结晶紫溶液为模拟染料废水,研究了吸附剂粒径、溶液pH值、结晶紫的初始浓度、吸附剂用量、吸附时间、吸附温度对结晶紫吸附性能的影响。结果表明花生壳活性炭是具有高去除率的廉价吸附剂,最大去除率达96%。结晶紫染料在花生壳活性炭上的吸附过程符合二级动力学模型和Freundlich等温吸附方程。     

Straw management and optimal N fertilization in seed production of timothy (Phleum Pratense L.) and Meadow Fescue (Festuca Pratensis Huds.)

The market for herbage seed straw has diminished in many seed-production areas due to less livestock. Seed growers are therefore looking for alternatives to straw removal, which up to now has been the most common practice. During 2000–2006, different alternative straw chopping methods, both at the back of the combiner and with a tractor-mounted flail-chopper, and field burning strategies were evaluated in seed crops of timothy (Phleum pratense) and meadow fescue (Festuca pratensis) in southeast Norway. The requirement for an extra N input in autumn (30–40?kg ha^-1) when practising straw chopping was also examined. Compared to straw removal, straw chopping at the back of the combiner during seed harvest did not reduce seed yield in the following year as long as stubble height was low (<10?cm in timothy) and the straw spread uniformly in the field. On average, seed yield was 1–4% and 1–9% higher compared to straw removal in timothy and meadow fescue, respectively. If the chopped straw was spread unevenly, or long stubble was left at combining, it is recommended to use a tractor-mounted flail-chopper after harvest. The experiments did not provide any support for an extra input of nitrogen in autumn, either in timothy or meadow fescue, when the straw was chopped rather than removed. Burning of stubble and straw soon after seed harvest was another efficient clean-up method after harvest, which increased seed yield 9–15% and 17–20% compared to straw removal in the two species, respectively. However, as the burning method is risky and causes smoke emissions, it is normally not recommended. It is concluded that for most seed growers, the most effective, least laborious and most environment-friendly alternative to straw removal will be to chop the straw at the back of the combiner during seed harvest.