植保无人机对水稻病虫害防治条件与防效的研究

为了探索植保无人机对水稻病虫害防治条件和防治效果,研究了植保无人机飞行高度、飞行速度、飞防助剂等条件对农药雾滴特性的影响,同时研究了两种不同施药方式对水稻纹枯病、稻曲病、螟虫防效的影响。结果表明,在植保无人机飞行高度距离水稻冠层2 m、飞行速度3 m·s^-1时,雾滴沉降密度（22.3个·cm^-2）最大,雾滴在水稻冠层不同部位的沉降密度存在差异：上部＞中部＞下部;添加飞防助剂药液湿润面积增加764%,雾滴中直径、覆盖率由未添加助剂前 256.3 μm、5.56%增加至327.5 μm、9.82%,雾滴密度由未添加助剂前20.3个·cm^-2降低至16.4个·cm^-2。在水稻孕穗期,相同药剂配方条件下,植保无人机喷施化学药剂和生物药剂对水稻纹枯病的防治效果分别为86.20%、83.20%,显著优于传统人工电动喷雾器喷洒防治效果;而对稻曲病的防治效果分别为86.51%、84.01%,对螟虫的防治效果分别为89.32%、81.47%,两种喷药方式的防治效果无显著差异。研究结果表明,植保无人机在最适飞行高度、飞行速度和添加飞防助剂等条件下,对水稻病虫害防治效果显著,具有大面积推广应用价值。     

沉积作用及应力历史对自重应力和沉降的影响

土体的沉积作用和应力历史会影响土体自重应力的确定,也会影响地基最终沉降量的确定。鉴于e-lnp比e-lgp坐标图能更方便、精确地描述线性问题,根据e-lnp坐标图推导沉积作用对成层土、正常固结土、超固结土的自重应力与沉降影响的计算式。用该计算式对昆明滇池国际会展中心部分深厚软土地基的自重应力和最终沉降量进行计算,并用计算结果和不考虑沉积作用及应力历史影响的计算结果进行对比分析,结果表明,沉积作用对深厚软粘土自重应力和最终沉降量计算值的影响非常显著,并且土体厚度越厚、上覆荷载越大,其影响越明显。     

混凝法去除水中TiO2纳米颗粒

为了探讨混凝法去除水中纳米颗粒的可行性及最佳条件,研究了无机混凝剂（PAC、PFS、PAFC）和有机絮凝剂（CPAM、APAM、NPAM）对TiO₂纳米颗粒的去除效果,并考察了投加量、pH、沉淀时间、水力条件及有机无机复配对TiO₂纳米颗粒去除效率的影响。单独投加PAC、PFS和PAFC时,三者对应的最高去除率分别为92.51%、84.43%、95.66%。单独投加CPAM、APAM、NPAM时三者对应的去除率仅为61.72%、29.06%、55.37%。复配最佳混凝条件为：投加40 mg/LPAC和3 mg/LCPAM,pH值为9,G值143.5/s,沉淀时间15 min,此时,TiO₂纳米颗粒去除率为99.6%。     

水电站水库泥沙淤积的二维数学模型

通过二维数学模型模拟水电站水库泥沙淤积情况,模拟河段起于大坝上游约600 m,止于大坝下游约400 m.计算断面在1∶2 000地形图上剖分20个库区大断面,断面平均间距500 m,并通过模型试验论证数学模型模拟水库泥沙淤积变化可行性.结果表明:水库泥沙淤积形态为三角洲淤积形态,水库运行历时1 a,三角洲洲头不断地向下游前进,最终到达坝前,坝前泥沙淤积高程达1 347 m,而水库泥沙淤积则向库尾高边滩发展,“翘尾巴”现象明显.水库运行1 a后,排沙比均稳定在90%以上,水库冲淤达到平衡后,采用“蓄清排浑”的运行调度方式冲沙,在泄洪冲沙底孔前形成冲刷漏斗,漏斗为三维形态,漏斗顺水流方向坡降约为1∶5.0~1∶7.0,侧向边坡约为1∶3.5~1∶4.5.取水口基本在冲刷漏斗范围内,能保持取水“门前清”.泥沙淤积的数学模型与模型试验成果基本吻合,数学模型模拟水库泥沙淤积变化可行的.     

Detection of QTLs for bread‐making quality in wheat using a recombinant inbred line population

Whereas gluten fraction accounts for 30–60% of the variation in wheat bread‐making quality, there remains substantial variation determined by non‐gluten factors. The objective of this study was to detect new loci for wheat quality. The genetics of sodium dodecyl sulphate‐sedimentation volume (Ssd), grain hardness (GH), grain protein content, wet gluten content (WGC) and water absorption (Abs) in a set of 198 recombinant inbred lines derived from two commercial varieties was studied by quantitative trait loci (QTL) analysis. A genetic map based on 255 marker loci, consisting of 250 simple sequence repeat markers and five glutenin loci, Glu‐A1, Glu‐B1, Glu‐D1, Glu‐B3 and Glu‐D3, was constructed. A total of 73 QTLs were detected for all traits. A major QTL for GH was detected on chromosome 1B and its relative contribution to phenotypic variation was 27.7%. A major QTL for Abs on chromosome 5D explained more than 30% of the phenotypic variation. Variations in Ssd were explained by four kinds of genes. Some QTLs for correlated traits mapped to the same regions forming QTL clusters or indicated pleiotropic effects.     

饲料添加剂茶多酚提取工艺研究

采用相同的茶叶原料,对提取茶多酚的溶剂萃取法、离子沉淀法、树脂吸附法3种方法进行了对比试验。还研究出一套将离子沉淀法和吸附法相结合的新工艺,既避免了有毒溶剂的毒害和对环境的污染,又能获得质量较好、成本较低的茶多酚产品,适合于实验室或小批量生产茶多酚使用。     

三沙湾大黄鱼网箱养殖衍生有机物的沉降特征

为了解三沙湾大黄鱼（）网箱养殖衍生有机物（AOM）的沉降特征,采用原位实验方法,收集区域内使用颗粒饲料和冰鲜饵料两种典型饲喂方式下距离网箱200 m范围内AOM样品,分析其沉降量、营养物质[颗粒有机物（POM）、颗粒有机碳（POC）、颗粒态氮（PN）、总磷（TP）]沉降通量和扩散特点。研究结果表明,饲喂颗粒饲料状态下AOM沉降量显著高于投喂冰鲜饵料,两者均值分别为（563.66±119.18）g/（m²·d）和（266.07±139.15）g/（m²·d）。POM、POC、PN和TP沉降通量在两种饲喂方式下的差异与之相似,饲喂颗粒饲料时各参数均值分别为（27.25±2.43）g/（m²·d）、（6.03±0.58）g/（m²·d）、（0.66±0.06）g/（m²·d）和（0.39±0.04）g/（m²·d）;饲喂冰鲜饵料时各参数均值分别为（13.04±1.62）g/（m²·d）,（3.57±0.45）g/（m²·d）、（0.51±0.06）g/（m²·d）和（0.22±0.04）g/（m²·d）。沿近底层海流主导流向距离养殖网箱100 m的空间范围内,AOM沉降量和营养物质沉降通量均呈现自网箱处递减的变化特征,下降程度在饲喂冰鲜饵料时尤为显著。AOM中POC、PN和TP含量在饲喂冰鲜饵料时较高,在距离养殖网箱50 m范围内呈现递减趋势。综上,在三沙湾大黄鱼网箱养殖过程中,投喂颗粒饲料引发的环境污染程度高于冰鲜饵料,两种情形下的AOM沉降影响主要限于距离养殖网箱50~100 m的空间范围。三沙湾内饲喂颗粒饲料引发较高营养物质沉降通量源于较大的AOM沉降量,此现象说明养殖过程中可能存在颗粒饲料过度投喂、饵料利用效率较低等问题,围绕此类问题的针对性研究对于减缓区域内养殖活动的环境影响具有重要意义。     

Human modification of stream valleys in the western plateau of São Paulo,Brazil: implications for environmental narratives and management

Deforestation, agricultural land uses and urbanization have altered stream channels and floodplains in many regions of the world, yet occurrences of post‐settlement alluvium (PSA) and benchmark pre‐settlement horizons (Palaeosols) are unreported in many tropical and subtropical developing countries. Twentieth century land uses, motivated strongly by state subsidies in the cases of coffee and cotton cultivation and soy – wheat double cropping, caused soil erosion and the corresponding formation of PSA and stream‐channel changes in small catchments of the Western Plateau of São Paulo State, Brazil. Analysis of land‐use changes suggests necessary alteration of regional environmental management for restoration planning, water quality monitoring and control of gully erosion. Narratives of regional environmental change should address the impacts of agropastoral land uses on soil and water resources, rather than concentrating on deforestation and forest land cover. Copyright © 2000 John Wiley & Sons, Ltd.     

复合稳定剂对调配型酸性乳饮料稳定性的影响

[目的]解决调配型酸乳饮料因脂肪上浮和蛋白质沉淀而导致稳定性很差的问题。[方法]利用果胶、羧甲基纤维素钠、大豆水溶性多糖、海藻酸丙二醇酯进行复配对调配型酸乳饮料稳定性进行研究。[结果]研究得出,果胶浓度0.11%,羧甲基纤维素钠浓度0.05%,大豆水溶性多糖浓度0.11%,PGA浓度0.13%时,酸性乳饮料稳定性最好,离心沉淀率为2.5%。[结论]该研究可为生产出稳定性较好的调配型酸乳饮料提供技术支持。