喉管直径对文丘里施肥器性能影响的数值模拟

基于雷诺时均Navier-Stokes方程和标准k-ε湍流模型,利用Fluent软件对文丘里施肥器的内部流动进行了数值模拟,并对数值计算方法的正确性进行了验证.模拟分析了喉管进口直径为4,5,6 mm,以及出口直径与进口直径之比λ为1.0,1.1,1.2,1.3和1.4时15种结构方案的吸肥性能.结果表明：喉管直径对喉管及扩散段内流动特性、吸肥性能和效率均有一定影响,但出口直径与进口直径之比λ对文丘里施肥器性能的影响要明显甚于喉管进口直径.根据效率最高原则,喉管直径比应为1.2～1.3.建立了λ=1.2或1.3时文丘里施肥器吸肥效率与流量比之间的回归模型,并应用回归模型预测了吸肥效率最大值.喉管进口直径4 mm的文丘里施肥器当直径比为1.3时吸肥效率可达到15.5%,与直径比为1.0相比,前者的扩散段内部流动平顺、无漩涡出现,且相同横截面的平均湍动能值要小.该研究结果为文丘里施肥器的优化设计提供了一定的理论参考.     

镜鲤体重的QTL定位

本研究利用217个微卫星标记和336个SNPs标记对德国镜鲤F2代68个个体基因组DNA进行基因型检测。其中507个标记共组成62个连锁群,覆盖基因组总长度为2805．85cM,标记问平均距离为6-31cM;利用软件MapQTL4．0采用区间作图法对体重性状进行QTL定位分析。研究结果共检测到14个与体重性状有关的QTLs,分布于9个连锁群。其中BIV-5-J有最大的LOD值,为4．46;BIV—I-1的LOD值最小,为2．25。单个QTL平均解释表型变异介于14．10％～45．50％之间,其中贡献率大于20％的主效QTLs有9个。通过BLASTX与斑马鱼蛋白质序列数据库进行序列比对,找到了与斑马鱼酰基辅酶A脱氢酶蛋白、胰淀粉酶仅2蛋白、Apoebprotein和甘油醛-3-磷酸脱氢酶蛋白同源的分子标记。本研究结果对分子标记辅助育种具有重要应用价值。     

Metabolite profiles for Antrodia cinnamomea fruiting bodies harvested at different culture ages and from different wood substrates

Antrodia cinnamomea is a precious edible fungus endemic to Taiwan that has long been used as a folk remedy for health promotion and for treating various diseases. In this study, an index of 13 representative metabolites from the ethanol extract of A. cinnamomea fruiting body was established for use in quality evaluation. Most of the index compounds selected, particularly the ergostane-type triterpenoids and polyacetylenes, possess good anti-inflammation activity. A comparison of the metabolite profiles of different ethanol extracts from A. cinnamomea strains showed silmilar metabolites when the strains were grown on the original host wood (Cinnamomum kanehirai) and harvested after the same culture time period (9 months). Furthermore, the amounts of typical ergostane-type triterpenoids in A. cinnamomea increased with culture age. Culture substrates also influenced metabolite synthesis; with the same culture age, A. cinnamomea grown on the original host wood produced a richer array of metabolites than A. cinnamomea cultured on other wood species. We conclude that analysis of a fixed group of compounds including triterpenoids, benzolics, and polyacetylenes constitutes a suitable, reliable system to evaluate the quality of ethanol extract from A. cinnamomea fruiting bodies. The evaluation system established in this study may provide a platform for analysis of the products of A. cinnamomea.     

防御酶系对山茶灰斑病诱导抗性的响应

为揭示水杨酸(SA)诱导山茶产生抗病性反应机制,采用琼脂平板法测定了SA对山茶灰斑病菌Pestalotiopsis guepinii ( Desm.) Stey的影响.结果表明,浓度为0～5 mmol/L的SA对该菌的生长没有抑制作用.用SA喷雾涂布叶片诱导山茶抗性,其植株内过氧化物酶(POD)、多酚氧化酶(PPO )、过氧化氮酶(CAT)、苯丙氛酸解氨酶(PAL)等防御酶时山茶灰斑病菌诱导信号有不同响应.诱导并挑战接种处理的植株体内上述酶活性比只诱导不接种处理上升速度快,不同浓度的SA诱导及诱导后挑战接种植株体内的POD,PPO,CAT,PAL活性与SA浓度呈正相关.各防御酶活性与感病指数的相关性分析表明,CAT活性与感病指数显著负相关(r = - 0.9730),除PPO与感病指数的相关系数很低外,其它酶均较高,尽管未达到显著水平,但仍说明POD,PAL在诱导山茶抗病性中具有重要作用.     

Insecticidal compounds from the essential oil of Chinese medicinal herb Atractylodes chinensis

BACKGROUND: In a screening programme for new agrochemicals from Chinese medicinal herbs, the essential oil of Atractylodes chinensis (DC.) Koidz was found to possess strong insecticidal activity against the common vinegar fly, Drosophila melanogaster L. The essential oil was extracted via hydrodistillation, and its constituents were determined by GC‐MS analysis. RESULTS: The main components of A. chinensis essential oil were β‐eudesmol (21.05%), β‐selinene (11.75%), γ‐elemene (7.16%) and isopetasam (5.36%). Bioactivity‐directed chromatographic separation on repeated silica gel columns led to the isolation of five compounds, namely atractylon, α‐elemol, β‐eudesmol, hinesol and β‐selinene. β‐Selinene, α‐elemol and hinesol showed pronounced contact toxicity against D. melanogaster adults, with LD₅₀ values of 0.55, 0.65 and 0.71 µg adult^?1 respectively. Atractylon and β‐eudesmol were also toxic to the fruit flies (LD₅₀ = 1.63 and 2.65 µg adult^?1 respectively), while the crude oil had an LD₅₀ value of 2.44 µg adult^?1. CONCLUSION: The findings suggested that the essential oil of Atractylodes chinensis and its active constituents may be explored as natural potential insecticides. Copyright © 2011 Society of Chemical Industry     

电磁感应加热重熔Niwc25粉末涂层与基体结合机理的研究

介绍利用高频电磁感应加热重熔NiWC25金属合金粉末涂层与基体结合机理的有关研究结果。采用电子扫描显微镜、波谱分析及能谱分析等手段,证明了涂层与基体具有明显的钎焊特征;金属元素Fe,Ni,W在涂层与基体之间的扩散效应产生了冶金结合,扩散深度可达20—25μm。     

果园自动对靶静电喷雾机设计与试验研究

为适应果园病虫害防治的需要，研制了一种轻便、高效、省药、能减少对环境的污染、与国产小中型拖拉机配套的果园自动对靶静电喷雾机。通过多次结构改进和各种试验，采用基于红外传感探测技术，探测靶标的有无，将传统的连续喷雾改变为自动对靶控制喷雾，与风送式果园喷雾机连续喷雾相比，可以节省药液50%～75%以上，同时还解决了风送式低量与静电喷雾等关键技术问题。     

氮磷等比与以磷定氮条件下玉米的最大施肥量研究

以前的研究已认识到种植玉米的土壤具有平衡与不平衡的土壤养分供应类型,因而其高产施肥需要相应的养分配比。本研究以养分平衡供应的山西石灰性褐土为对象,按照同步增加氮磷用量和以磷定氮等两种施肥量确定方法设置氮磷施肥量,探讨高产玉米的最大施肥量和最佳施肥比例。研究表明,氮磷等比施肥下玉米最大施氮量较以磷定氮增大46 kg hm-2,产量增加738 kg hm-2;而玉米最佳施氮量较以磷定氮增加39 kg hm-2,产量增加723 kg hm-2。氮磷等比施肥下最佳施氮量氮素的增产效益极大。试验说明氮磷施用比例是影响玉米最大施氮量及其肥效的重要因素。在供试的氮磷养分平衡供应条件下同步增加氮磷用量可以得到两者统一的玉米高产最佳施肥量点。本研究提出,根据土壤养分平衡供应特征调整施肥养分比例可能是作物高产施肥且提高肥料利用率的途径。     

苏北滨海盐渍土的形成和演化

为了加速滨海盐渍土的垦殖和改良利用,建设高产稳产的农业生产基地,必须弄清滨海盐渍土的形成演化规律,提高我们认识自然,改造自然的自觉性,减少片面性和盲目性.